1
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Mrnjavac N, Degli Esposti M, Mizrahi I, Martin WF, Allen JF. Three enzymes governed the rise of O 2 on Earth. BIOCHIMICA ET BIOPHYSICA ACTA. BIOENERGETICS 2024; 1865:149495. [PMID: 39004113 PMCID: PMC7616410 DOI: 10.1016/j.bbabio.2024.149495] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2024] [Revised: 06/30/2024] [Accepted: 07/02/2024] [Indexed: 07/16/2024]
Abstract
Current views of O2 accumulation in Earth history depict three phases: The onset of O2 production by ∼2.4 billion years ago; 2 billion years of stasis at ∼1 % of modern atmospheric levels; and a rising phase, starting about 500 million years ago, in which oxygen eventually reached modern values. Purely geochemical mechanisms have been proposed to account for this tripartite time course of Earth oxygenation. In particular the second phase, the long period of stasis between the advent of O2 and the late rise to modern levels, has posed a puzzle. Proposed solutions involve Earth processes (geochemical, ecosystem, day length). Here we suggest that Earth oxygenation was not determined by geochemical processes. Rather it resulted from emergent biological innovations associated with photosynthesis and the activity of only three enzymes: 1) The oxygen evolving complex of cyanobacteria that makes O2; 2) Nitrogenase, with its inhibition by O2 causing two billion years of oxygen level stasis; 3) Cellulose synthase of land plants, which caused mass deposition and burial of carbon, thus removing an oxygen sink and therefore increasing atmospheric O2. These three enzymes are endogenously produced by, and contained within, cells that have the capacity for exponential growth. The catalytic properties of these three enzymes paved the path of Earth's atmospheric oxygenation, requiring no help from Earth other than the provision of water, CO2, salts, colonizable habitats, and sunlight.
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Affiliation(s)
- Natalia Mrnjavac
- Department of Biology, Institute for Molecular Evolution, Heinrich Heine University of Duesseldorf, Duesseldorf, Germany
| | | | - Itzhak Mizrahi
- Department of Life Sciences, Ben-Gurion University of the Negev and the National Institute for Biotechnology in the Negev, Marcus Family Campus, Be'er-Sheva, Israel
| | - William F Martin
- Department of Biology, Institute for Molecular Evolution, Heinrich Heine University of Duesseldorf, Duesseldorf, Germany
| | - John F Allen
- Research Department of Genetics, Evolution and Environment, University College London, Gower Street, London, UK.
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2
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Ramesh Sawant A, Pagal S, Prashanth K. Role of the NtrC family response regulator in nitrogen metabolism of Acinetobacter baumannii. Gene 2024; 924:148552. [PMID: 38734189 DOI: 10.1016/j.gene.2024.148552] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2023] [Revised: 05/02/2024] [Accepted: 05/08/2024] [Indexed: 05/13/2024]
Abstract
Acinetobacter baumannii is an important Gram-negative nosocomial pathogen that causes opportunistic infections and employs different mechanisms to survive in the presence of antibiotics in the host. Nutrient limitation is one of the important defense mechanisms of the mammalian immune system to fight against the colonization of pathogens like A. baumannii. The present study describes an NtrC-type Response Regulator (RR) A1S_1978 involved in modulating the metabolism and cell morphology of A. baumannii via a two-component system. This RR was found to be highly conserved in the Acinetobacter and other important Gram-negative pathogens. Sequence analysis reveals that this RR contains an HTH_8 DNA-binding domain. It is also observed that deletion of this RR resulted in elongated cell phenotype and altered colony morphology of A. baumannii. We showed that the ability of A. baumannii to form biofilm and pellicle is partly abolished upon deletion of this response regulator. We showed that mutant strains lacking RR A1S_1978 have diminished growth in the absence of the nitrogen source. The transcriptome analysis of the A1S_1978 deletion mutant revealed that 253 genes were differentially expressed, including 80 genes that were upregulated by at least 2-fold and 173 genes that were down regulated in the ΔA1S_1978 strain. The transcriptome data showed an association between the A1S_1978 RR and key genes related to various nitrogen and amino acid metabolism processes, which was further confirmed by real time PCR analysis. The deletion of this RR leads to a reduction in persister cell formation against ciprofloxacin antibiotic. Taken together the results of this investigation provide significant evidence that the RR A1S_1978 is a global regulator in A. baumannii.
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Affiliation(s)
- Ajit Ramesh Sawant
- Department of Biotechnology, School of Life Sciences, Pondicherry University, Pondicherry, India
| | - Sudhakar Pagal
- Department of Biotechnology, School of Life Sciences, Pondicherry University, Pondicherry, India
| | - K Prashanth
- Department of Biotechnology, School of Life Sciences, Pondicherry University, Pondicherry, India.
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3
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Ou J, Xie Q, Zhong ZR, Wang F, Huang MZ, Fang ZX, Kuang XY, Qin ZL, Luo SW. Genomic analysis and metabolic characteristics provide insights into inorganic nitrogen metabolism of novel bacterium Acinetobacter pittii J08. BIORESOURCE TECHNOLOGY 2024; 408:131228. [PMID: 39117239 DOI: 10.1016/j.biortech.2024.131228] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2024] [Revised: 07/19/2024] [Accepted: 08/05/2024] [Indexed: 08/10/2024]
Abstract
A novel A. pittii J08 with heterotrophic nitrification and aerobic denitrification (HN-AD) isolated from pond sediments could rapidly degrade inorganic nitrogen (N) and total nitrogen (TN-N) with ammonium (NH4+-N) preference. N degradation rate of NH4+-N, nitrite (NO2--N) and nitrate (NO3--N) were 3.9 mgL-1h-1, 3.0 mgL-1h-1 and 2.7 mgL-1h-1, respectively. In addition, strain J08 could effectively utilize most of detected low-molecular-weight carbon (LMWC) sources to degrade inorganic N with a wide adaptability to various culture conditions. Whole genome sequencing (WGS) analysis revealed that assembled genome of stain J08 possessed the crucial genes involved in dissimilatory/assimilatory NO3--N reduction and NH4+-N assimilation. These results indicated that strain J08 could be applied to wastewater treatment in aquaculture.
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Affiliation(s)
- Jie Ou
- State Key Laboratory of Developmental Biology of Freshwater Fish, Engineering Research Center of Polyploidy Fish Reproduction and Breeding of the State Education Ministry, College of Life Science, Hunan Normal University, Changsha 410081, China
| | - Qing Xie
- State Key Laboratory of Developmental Biology of Freshwater Fish, Engineering Research Center of Polyploidy Fish Reproduction and Breeding of the State Education Ministry, College of Life Science, Hunan Normal University, Changsha 410081, China
| | - Zi-Rou Zhong
- State Key Laboratory of Developmental Biology of Freshwater Fish, Engineering Research Center of Polyploidy Fish Reproduction and Breeding of the State Education Ministry, College of Life Science, Hunan Normal University, Changsha 410081, China
| | - Fei Wang
- State Key Laboratory of Developmental Biology of Freshwater Fish, Engineering Research Center of Polyploidy Fish Reproduction and Breeding of the State Education Ministry, College of Life Science, Hunan Normal University, Changsha 410081, China
| | - Ming-Zhu Huang
- National R&D Center for Freshwater Fish Processing, Jiangxi Normal University, Nanchang 330022, China
| | - Zi-Xuan Fang
- State Key Laboratory of Developmental Biology of Freshwater Fish, Engineering Research Center of Polyploidy Fish Reproduction and Breeding of the State Education Ministry, College of Life Science, Hunan Normal University, Changsha 410081, China
| | - Xu-Ying Kuang
- State Key Laboratory of Developmental Biology of Freshwater Fish, Engineering Research Center of Polyploidy Fish Reproduction and Breeding of the State Education Ministry, College of Life Science, Hunan Normal University, Changsha 410081, China
| | - Zi-Le Qin
- State Key Laboratory of Developmental Biology of Freshwater Fish, Engineering Research Center of Polyploidy Fish Reproduction and Breeding of the State Education Ministry, College of Life Science, Hunan Normal University, Changsha 410081, China
| | - Sheng-Wei Luo
- State Key Laboratory of Developmental Biology of Freshwater Fish, Engineering Research Center of Polyploidy Fish Reproduction and Breeding of the State Education Ministry, College of Life Science, Hunan Normal University, Changsha 410081, China.
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4
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Maslać N, Cadoux C, Bolte P, Murken F, Gu W, Milton RD, Wagner T. Structural comparison of (hyper-)thermophilic nitrogenase reductases from three marine Methanococcales. FEBS J 2024; 291:3454-3480. [PMID: 38696373 DOI: 10.1111/febs.17148] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2023] [Revised: 01/17/2024] [Accepted: 04/17/2024] [Indexed: 05/04/2024]
Abstract
The nitrogenase reductase NifH catalyses ATP-dependent electron delivery to the Mo-nitrogenase, a reaction central to biological dinitrogen (N2) fixation. While NifHs have been extensively studied in bacteria, structural information about their archaeal counterparts is limited. Archaeal NifHs are considered more ancient, particularly those from Methanococcales, a group of marine hydrogenotrophic methanogens, which includes diazotrophs growing at temperatures near 92 °C. Here, we structurally and biochemically analyse NifHs from three Methanococcales, offering the X-ray crystal structures from meso-, thermo-, and hyperthermophilic methanogens. While NifH from Methanococcus maripaludis (37 °C) was obtained through heterologous recombinant expression, the proteins from Methanothermococcus thermolithotrophicus (65 °C) and Methanocaldococcus infernus (85 °C) were natively purified from the diazotrophic archaea. The structures from M. thermolithotrophicus crystallised as isolated exhibit high flexibility. In contrast, the complexes of NifH with MgADP obtained from the three methanogens are superposable, more rigid, and present remarkable structural conservation with their homologues. They retain key structural features of P-loop NTPases and share similar electrostatic profiles with the counterpart from the bacterial model organism Azotobacter vinelandii. In comparison to the NifH from the phylogenetically distant Methanosarcina acetivorans, these reductases do not cross-react significantly with Mo-nitrogenase from A. vinelandii. However, they associate with bacterial nitrogenase when ADP·AlF 4 - is added to mimic a transient reactive state. Accordingly, detailed surface analyses suggest that subtle substitutions would affect optimal binding during the catalytic cycle between the NifH from Methanococcales and the bacterial nitrogenase, implying differences in the N2-machinery from these ancient archaea.
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Affiliation(s)
- Nevena Maslać
- Microbial Metabolism Research Group, Max Planck Institute for Marine Microbiology, Bremen, Germany
| | - Cécile Cadoux
- Department of Inorganic and Analytical Chemistry, Faculty of Sciences, University of Geneva, Switzerland
- National Centre of Competence in Research (NCCR) Catalysis, University of Geneva, Switzerland
| | - Pauline Bolte
- Microbial Metabolism Research Group, Max Planck Institute for Marine Microbiology, Bremen, Germany
| | - Fenja Murken
- Microbial Metabolism Research Group, Max Planck Institute for Marine Microbiology, Bremen, Germany
| | - Wenyu Gu
- Laboratory of Microbial Physiology and Resource Biorecovery, School of Architecture, Civil and Environmental Engineering, École Polytechnique Fédéral de Lausanne, Switzerland
| | - Ross D Milton
- Department of Inorganic and Analytical Chemistry, Faculty of Sciences, University of Geneva, Switzerland
- National Centre of Competence in Research (NCCR) Catalysis, University of Geneva, Switzerland
| | - Tristan Wagner
- Microbial Metabolism Research Group, Max Planck Institute for Marine Microbiology, Bremen, Germany
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5
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Abdul Halim MF, Hanson EH, Costa KC. Methanococcus maripaludis. Trends Microbiol 2024; 32:823-824. [PMID: 38702257 DOI: 10.1016/j.tim.2024.04.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2024] [Revised: 04/17/2024] [Accepted: 04/18/2024] [Indexed: 05/06/2024]
Affiliation(s)
| | - Emily H Hanson
- Department of Plant and Microbial Biology, University of Minnesota, St Paul, MN, USA
| | - Kyle C Costa
- Department of Plant and Microbial Biology, University of Minnesota, St Paul, MN, USA.
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6
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Schuman Z, Xie Y, O'Keeffe S, Guan X, Sha J, Sun J, Wohlschlegel JA, Park JO, Liu C. Integrated Proteomics and Metabolomics Reveal Altered Metabolic Regulation of Xanthobacter autotrophicus under Electrochemical Water-Splitting Conditions. ACS APPLIED MATERIALS & INTERFACES 2024. [PMID: 39058742 DOI: 10.1021/acsami.4c07363] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/28/2024]
Abstract
Biological-inorganic hybrid systems are a growing class of technologies that combine microorganisms with materials for a variety of purposes, including chemical synthesis, environmental remediation, and energy generation. These systems typically consider microorganisms as simple catalysts for the reaction of interest; however, other metabolic activity is likely to have a large influence on the system performance. The investigation of biological responses to the hybrid environment is thus critical to the future development and optimization. The present study investigates this phenomenon in a recently reported hybrid system that uses electrochemical water splitting to provide reducing equivalents to the nitrogen-fixing bacteria Xanthobacter autotrophicus for efficient reduction of N2 to biomass that may be used as fertilizer. Using integrated proteomic and metabolomic methods, we find a pattern of differentiated metabolic regulation under electrochemical water-splitting (hybrid) conditions with an increase in carbon fixation products glycerate-3-phosphate and acetyl-CoA that suggests a high energy availability. We further report an increased expression of proteins of interest, namely, those responsible for nitrogen fixation and assimilation, which indicate increased rates of nitrogen fixation and support previous observations of faster biomass accumulation in the hybrid system compared to typical planktonic growth conditions. This work complicates the inert catalyst view of biological-inorganic hybrids while demonstrating the power of multiomics analysis as a tool for deeper understanding of those systems.
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Affiliation(s)
- Zachary Schuman
- Department of Chemistry and Biochemistry, University of California Los Angeles, Los Angeles, California 90095, United States
| | - Yongchao Xie
- Department of Chemistry and Biochemistry, University of California Los Angeles, Los Angeles, California 90095, United States
| | - Samantha O'Keeffe
- Department of Chemical and Biomolecular Engineering, University of California Los Angeles, Los Angeles, California 90095, United States
| | - Xun Guan
- Department of Chemistry and Biochemistry, University of California Los Angeles, Los Angeles, California 90095, United States
| | - Jihui Sha
- Department of Biological Chemistry, University of California Los Angeles, Los Angeles, California 90095, United States
| | - Jingwen Sun
- Department of Chemistry and Biochemistry, University of California Los Angeles, Los Angeles, California 90095, United States
| | - James A Wohlschlegel
- Department of Biological Chemistry, University of California Los Angeles, Los Angeles, California 90095, United States
| | - Junyoung O Park
- Department of Chemical and Biomolecular Engineering, University of California Los Angeles, Los Angeles, California 90095, United States
- California NanoSystems Institute, University of California Los Angeles, Los Angeles, California 90095, United States
| | - Chong Liu
- Department of Chemistry and Biochemistry, University of California Los Angeles, Los Angeles, California 90095, United States
- California NanoSystems Institute, University of California Los Angeles, Los Angeles, California 90095, United States
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7
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Liao HS, Lee KT, Chung YH, Chen SZ, Hung YJ, Hsieh MH. Glutamine induces lateral root initiation, stress responses, and disease resistance in Arabidopsis. PLANT PHYSIOLOGY 2024; 195:2289-2308. [PMID: 38466723 DOI: 10.1093/plphys/kiae144] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Revised: 02/06/2024] [Accepted: 02/20/2024] [Indexed: 03/13/2024]
Abstract
The production of glutamine (Gln) from NO3- and NH4+ requires ATP, reducing power, and carbon skeletons. Plants may redirect these resources to other physiological processes using Gln directly. However, feeding Gln as the sole nitrogen (N) source has complex effects on plants. Under optimal concentrations, Arabidopsis (Arabidopsis thaliana) seedlings grown on Gln have similar primary root lengths, more lateral roots, smaller leaves, and higher amounts of amino acids and proteins compared to those grown on NH4NO3. While high levels of Gln accumulate in Arabidopsis seedlings grown on Gln, the expression of GLUTAMINE SYNTHETASE1;1 (GLN1;1), GLN1;2, and GLN1;3 encoding cytosolic GS1 increases and expression of GLN2 encoding chloroplastic GS2 decreases. These results suggest that Gln has distinct effects on regulating GLN1 and GLN2 gene expression. Notably, Arabidopsis seedlings grown on Gln have an unexpected gene expression profile. Compared with NH4NO3, which activates growth-promoting genes, Gln preferentially induces stress- and defense-responsive genes. Consistent with the gene expression data, exogenous treatment with Gln enhances disease resistance in Arabidopsis. The induction of Gln-responsive genes, including PATHOGENESIS-RELATED1, SYSTEMIC ACQUIRED RESISTANCE DEFICIENT1, WRKY54, and WALL ASSOCIATED KINASE1, is compromised in salicylic acid (SA) biosynthetic and signaling mutants under Gln treatments. Together, these results suggest that Gln may partly interact with the SA pathway to trigger plant immunity.
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Affiliation(s)
- Hong-Sheng Liao
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei 11529, Taiwan
| | - Kim-Teng Lee
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei 11529, Taiwan
- Molecular and Biological Agricultural Sciences, The Taiwan International Graduate Program, Academia Sinica, Taipei 11529, Taiwan
- Biotechnology Center, National Chung-Hsing University, Taichung 40227, Taiwan
| | - Yi-Hsin Chung
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei 11529, Taiwan
| | - Soon-Ziet Chen
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei 11529, Taiwan
| | - Yi-Jie Hung
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei 11529, Taiwan
- Department of Life Sciences, National Central University, Taoyuan 32001, Taiwan
| | - Ming-Hsiun Hsieh
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei 11529, Taiwan
- Molecular and Biological Agricultural Sciences, The Taiwan International Graduate Program, Academia Sinica, Taipei 11529, Taiwan
- Biotechnology Center, National Chung-Hsing University, Taichung 40227, Taiwan
- Department of Life Sciences, National Central University, Taoyuan 32001, Taiwan
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8
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Salinas P, Bibak S, Cantos R, Tremiño L, Jerez C, Mata-Balaguer T, Contreras A. Studies on the PII-PipX-NtcA Regulatory Axis of Cyanobacteria Provide Novel Insights into the Advantages and Limitations of Two-Hybrid Systems for Protein Interactions. Int J Mol Sci 2024; 25:5429. [PMID: 38791467 PMCID: PMC11121479 DOI: 10.3390/ijms25105429] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2024] [Revised: 05/11/2024] [Accepted: 05/12/2024] [Indexed: 05/26/2024] Open
Abstract
Yeast two-hybrid approaches, which are based on fusion proteins that must co-localise to the nucleus to reconstitute the transcriptional activity of GAL4, have greatly contributed to our understanding of the nitrogen interaction network of cyanobacteria, the main hubs of which are the trimeric PII and the monomeric PipX regulators. The bacterial two-hybrid system, based on the reconstitution in the E. coli cytoplasm of the adenylate cyclase of Bordetella pertussis, should provide a relatively faster and presumably more physiological assay for cyanobacterial proteins than the yeast system. Here, we used the bacterial two-hybrid system to gain additional insights into the cyanobacterial PipX interaction network while simultaneously assessing the advantages and limitations of the two most popular two-hybrid systems. A comprehensive mutational analysis of PipX and bacterial two-hybrid assays were performed to compare the outcomes between yeast and bacterial systems. We detected interactions that were previously recorded in the yeast two-hybrid system as negative, as well as a "false positive", the self-interaction of PipX, which is rather an indirect interaction that is dependent on PII homologues from the E. coli host, a result confirmed by Western blot analysis with relevant PipX variants. This is, to our knowledge, the first report of the molecular basis of a false positive in the bacterial two-hybrid system.
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Affiliation(s)
| | | | | | | | | | | | - Asunción Contreras
- Departamento. de Fisiología, Genética y Microbiología, Universidad de Alicante, 03690 San Vicente del Raspeig, Spain; (P.S.); (S.B.); (R.C.); (L.T.); (C.J.); (T.M.-B.)
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9
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Liu X, Li J, Zhang Z, He Y, Wang M, Zhao Y, Lin S, Liu T, Liao Y, Zhang N, Yuan K, Ling Y, Liu Z, Chen X, Chen Z, Chen R, Wang X, Gu B. Acetylation of xenogeneic silencer H-NS regulates biofilm development through the nitrogen homeostasis regulator in Shewanella. Nucleic Acids Res 2024; 52:2886-2903. [PMID: 38142446 PMCID: PMC11014242 DOI: 10.1093/nar/gkad1219] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Revised: 12/08/2023] [Accepted: 12/12/2023] [Indexed: 12/26/2023] Open
Abstract
Adjusting intracellular metabolic pathways and adopting suitable live state such as biofilms, are crucial for bacteria to survive environmental changes. Although substantial progress has been made in understanding how the histone-like nucleoid-structuring (H-NS) protein modulates the expression of the genes involved in biofilm formation, the precise modification that the H-NS protein undergoes to alter its DNA binding activity is still largely uncharacterized. This study revealed that acetylation of H-NS at Lys19 inhibits biofilm development in Shewanella oneidensis MR-1 by downregulating the expression of glutamine synthetase, a critical enzyme in glutamine synthesis. We further found that nitrogen starvation, a likely condition in biofilm development, induces deacetylation of H-NS and the trimerization of nitrogen assimilation regulator GlnB. The acetylated H-NS strain exhibits significantly lower cellular glutamine concentration, emphasizing the requirement of H-NS deacetylation in Shewanella biofilm development. Moreover, we discovered in vivo that the activation of glutamine biosynthesis pathway and the concurrent suppression of the arginine synthesis pathway during both pellicle and attached biofilms development, further suggesting the importance of fine tune nitrogen assimilation by H-NS acetylation in Shewanella. In summary, posttranslational modification of H-NS endows Shewanella with the ability to respond to environmental needs by adjusting the intracellular metabolism pathways.
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Affiliation(s)
- Xiaoxiao Liu
- Laboratory Medicine, Guangdong Provincial People's Hospital (Guangdong Academy of Medical Sciences), Southern Medical University, Guangzhou 510000, China
- Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, Innovation Academy of South China Sea Ecology and Environmental Engineering, South China Sea Institute of Oceanology, Chinese Academy of Sciences, No. 1119, Haibin Road, Nansha District, Guangzhou 511458, China
- Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), No. 1119, Haibin Road, Nansha District, Guangzhou 511458, China
| | - Jun Li
- Laboratory Medicine, Guangdong Provincial People's Hospital (Guangdong Academy of Medical Sciences), Southern Medical University, Guangzhou 510000, China
| | - Zhixuan Zhang
- Laboratory Medicine, Guangdong Provincial People's Hospital (Guangdong Academy of Medical Sciences), Southern Medical University, Guangzhou 510000, China
- School of Medicine, South China University of Technology, Guangzhou, Guangdong 510080, China
| | - Yizhou He
- Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, Innovation Academy of South China Sea Ecology and Environmental Engineering, South China Sea Institute of Oceanology, Chinese Academy of Sciences, No. 1119, Haibin Road, Nansha District, Guangzhou 511458, China
| | - Mingfang Wang
- Laboratory Medicine, Guangdong Provincial People's Hospital (Guangdong Academy of Medical Sciences), Southern Medical University, Guangzhou 510000, China
| | - Yunhu Zhao
- Laboratory Medicine, Guangdong Provincial People's Hospital (Guangdong Academy of Medical Sciences), Southern Medical University, Guangzhou 510000, China
| | - Shituan Lin
- Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, Innovation Academy of South China Sea Ecology and Environmental Engineering, South China Sea Institute of Oceanology, Chinese Academy of Sciences, No. 1119, Haibin Road, Nansha District, Guangzhou 511458, China
- Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), No. 1119, Haibin Road, Nansha District, Guangzhou 511458, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Tianlang Liu
- Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, Innovation Academy of South China Sea Ecology and Environmental Engineering, South China Sea Institute of Oceanology, Chinese Academy of Sciences, No. 1119, Haibin Road, Nansha District, Guangzhou 511458, China
- Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), No. 1119, Haibin Road, Nansha District, Guangzhou 511458, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yiwen Liao
- Laboratory Medicine, Guangdong Provincial People's Hospital (Guangdong Academy of Medical Sciences), Southern Medical University, Guangzhou 510000, China
| | - Ni Zhang
- Laboratory Medicine, Guangdong Provincial People's Hospital (Guangdong Academy of Medical Sciences), Southern Medical University, Guangzhou 510000, China
| | - Kaixuan Yuan
- Laboratory Medicine, Guangdong Provincial People's Hospital (Guangdong Academy of Medical Sciences), Southern Medical University, Guangzhou 510000, China
| | - Yong Ling
- Laboratory Medicine, Guangdong Provincial People's Hospital (Guangdong Academy of Medical Sciences), Southern Medical University, Guangzhou 510000, China
| | - Ziyao Liu
- Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, Innovation Academy of South China Sea Ecology and Environmental Engineering, South China Sea Institute of Oceanology, Chinese Academy of Sciences, No. 1119, Haibin Road, Nansha District, Guangzhou 511458, China
- Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), No. 1119, Haibin Road, Nansha District, Guangzhou 511458, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xiaozhong Chen
- Laboratory Medicine, Guangdong Provincial People's Hospital (Guangdong Academy of Medical Sciences), Southern Medical University, Guangzhou 510000, China
| | - Zhe Chen
- Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, Innovation Academy of South China Sea Ecology and Environmental Engineering, South China Sea Institute of Oceanology, Chinese Academy of Sciences, No. 1119, Haibin Road, Nansha District, Guangzhou 511458, China
- Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), No. 1119, Haibin Road, Nansha District, Guangzhou 511458, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Ran Chen
- Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, Innovation Academy of South China Sea Ecology and Environmental Engineering, South China Sea Institute of Oceanology, Chinese Academy of Sciences, No. 1119, Haibin Road, Nansha District, Guangzhou 511458, China
- Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), No. 1119, Haibin Road, Nansha District, Guangzhou 511458, China
| | - Xiaoxue Wang
- Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, Innovation Academy of South China Sea Ecology and Environmental Engineering, South China Sea Institute of Oceanology, Chinese Academy of Sciences, No. 1119, Haibin Road, Nansha District, Guangzhou 511458, China
- Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), No. 1119, Haibin Road, Nansha District, Guangzhou 511458, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Bing Gu
- Laboratory Medicine, Guangdong Provincial People's Hospital (Guangdong Academy of Medical Sciences), Southern Medical University, Guangzhou 510000, China
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10
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Wang H, Zhang L, Tian C, Fan S, Zheng D, Song Y, Gao P, Li D. Effects of nitrogen supply on hydrogen-oxidizing bacterial enrichment to produce microbial protein: Comparing nitrogen fixation and ammonium assimilation. BIORESOURCE TECHNOLOGY 2024; 394:130199. [PMID: 38092074 DOI: 10.1016/j.biortech.2023.130199] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2023] [Revised: 12/10/2023] [Accepted: 12/10/2023] [Indexed: 12/23/2023]
Abstract
To investigate the effects of nitrogen source supply on microbial protein (MP) production by hydrogen-oxidizing bacteria (HOB) under continuous feed gas provision, a sequencing batch culture comparison (N2 fixation versus ammonium assimilation) was performed. The results confirmed that even under basic cultivation conditions, N2-fixing HOB (NF-HOB) communities showed higher levels of CO2 and N2 fixation (190.45 mg/L Δ CODt and 11.75 mg/L Δ TNbiomass) than previously known, with the highest biomass yield being 0.153 g CDW/g COD-H2. Rich ammonium stimulated MP synthesis and the biomass accumulation of communities (increased by 7.4 ~ 14.3 times), presumably through the enhancement of H2 and CO2 absorption. The micro mechanism may involve encouraging the enrichment of species like Xanthobacter and Acinetobacter then raising the abundance of nitrogenase and glutamate synthase to facilitate the nitrogen assimilation. This would provide NF-HOB with ideas for optimizing their MP synthesis activity.
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Affiliation(s)
- Haoran Wang
- CAS Key Laboratory of Environmental and Applied Microbiology, Environmental Microbiology Key Laboratory of Sichuan Province, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041, China; College of Life Sciences, Sichuan University, Chengdu 610065, China
| | - Lixia Zhang
- CAS Key Laboratory of Environmental and Applied Microbiology, Environmental Microbiology Key Laboratory of Sichuan Province, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Chang Tian
- CAS Key Laboratory of Environmental and Applied Microbiology, Environmental Microbiology Key Laboratory of Sichuan Province, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Sen Fan
- CAS Key Laboratory of Environmental and Applied Microbiology, Environmental Microbiology Key Laboratory of Sichuan Province, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041, China; College of Life Sciences, Sichuan University, Chengdu 610065, China
| | - Decong Zheng
- CAS Key Laboratory of Environmental and Applied Microbiology, Environmental Microbiology Key Laboratory of Sichuan Province, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yuhan Song
- CAS Key Laboratory of Environmental and Applied Microbiology, Environmental Microbiology Key Laboratory of Sichuan Province, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Ping Gao
- College of Life Sciences, Sichuan University, Chengdu 610065, China
| | - Daping Li
- CAS Key Laboratory of Environmental and Applied Microbiology, Environmental Microbiology Key Laboratory of Sichuan Province, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041, China; University of Chinese Academy of Sciences, Beijing 100049, China.
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11
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Skoog EJ, Bosak T. Predicted metabolic roles and stress responses provide insights into candidate phyla Hydrogenedentota and Sumerlaeota as members of the rare biosphere in biofilms from various environments. ENVIRONMENTAL MICROBIOLOGY REPORTS 2024; 16:e13228. [PMID: 38192240 PMCID: PMC10866078 DOI: 10.1111/1758-2229.13228] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Accepted: 12/11/2023] [Indexed: 01/10/2024]
Abstract
Pustular mats from Shark Bay, Western Australia, host complex microbial communities bound within an organic matrix. These mats harbour many poorly characterized organisms with low relative abundances (<1%), such as candidate phyla Hydrogenedentota and Sumerlaeota. Here, we aim to constrain the metabolism and physiology of these candidate phyla by analyzing two representative metagenome-assembled genomes (MAGs) from a pustular mat. Metabolic reconstructions of these MAGs suggest facultatively anaerobic, chemoorganotrophic lifestyles of both organisms and predict that both MAGs can metabolize a diversity of carbohydrate substrates. Ca. Sumerlaeota possesses genes involved in degrading chitin, cellulose and other polysaccharides, while Ca. Hydrogenedentota can metabolize cellulose derivatives in addition to glycerol, fatty acids and phosphonates. Both Ca. phyla can respond to nitrosative stress and participate in nitrogen metabolism. Metabolic comparisons of MAGs from Shark Bay and those from various polyextreme environments (i.e., hot springs, hydrothermal vents, subsurface waters, anaerobic digesters, etc.) reveal similar metabolic capabilities and adaptations to hypersalinity, oxidative stress, antibiotics, UV radiation, nitrosative stress, heavy metal toxicity and life in surface-attached communities. These adaptations and capabilities may account for the widespread nature of these organisms and their contributions to biofilm communities in a range of extreme surface and subsurface environments.
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Affiliation(s)
- Emilie J. Skoog
- Department of Earth, Atmospheric and Planetary SciencesMassachusetts Institute of TechnologyCambridgeMassachusettsUSA
- Integrative Oceanography DivisionScripps Institution of Oceanography, UC San DiegoLa JollaCaliforniaUSA
| | - Tanja Bosak
- Department of Earth, Atmospheric and Planetary SciencesMassachusetts Institute of TechnologyCambridgeMassachusettsUSA
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12
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Qin W, Wei SP, Zheng Y, Choi E, Li X, Johnston J, Wan X, Abrahamson B, Flinkstrom Z, Wang B, Li H, Hou L, Tao Q, Chlouber WW, Sun X, Wells M, Ngo L, Hunt KA, Urakawa H, Tao X, Wang D, Yan X, Wang D, Pan C, Weber PK, Jiang J, Zhou J, Zhang Y, Stahl DA, Ward BB, Mayali X, Martens-Habbena W, Winkler MKH. Ammonia-oxidizing bacteria and archaea exhibit differential nitrogen source preferences. Nat Microbiol 2024; 9:524-536. [PMID: 38297167 DOI: 10.1038/s41564-023-01593-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2023] [Accepted: 12/15/2023] [Indexed: 02/02/2024]
Abstract
Ammonia-oxidizing microorganisms (AOM) contribute to one of the largest nitrogen fluxes in the global nitrogen budget. Four distinct lineages of AOM: ammonia-oxidizing archaea (AOA), beta- and gamma-proteobacterial ammonia-oxidizing bacteria (β-AOB and γ-AOB) and complete ammonia oxidizers (comammox), are thought to compete for ammonia as their primary nitrogen substrate. In addition, many AOM species can utilize urea as an alternative energy and nitrogen source through hydrolysis to ammonia. How the coordination of ammonia and urea metabolism in AOM influences their ecology remains poorly understood. Here we use stable isotope tracing, kinetics and transcriptomics experiments to show that representatives of the AOM lineages employ distinct regulatory strategies for ammonia or urea utilization, thereby minimizing direct substrate competition. The tested AOA and comammox species preferentially used ammonia over urea, while β-AOB favoured urea utilization, repressed ammonia transport in the presence of urea and showed higher affinity for urea than for ammonia. Characterized γ-AOB co-utilized both substrates. These results reveal contrasting niche adaptation and coexistence patterns among the major AOM lineages.
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Affiliation(s)
- Wei Qin
- School of Biological Sciences, Institute for Environmental Genomics, University of Oklahoma, Norman, OK, USA.
- Department of Civil and Environmental Engineering, University of Washington, Seattle, WA, USA.
| | - Stephany P Wei
- Department of Civil and Environmental Engineering, University of Washington, Seattle, WA, USA
| | - Yue Zheng
- State Key Laboratory of Marine Environmental Science, College of the Environment and Ecology, Xiamen University, Xiamen, Fujian, China
| | - Eunkyung Choi
- Department of Microbiology and Cell Science, Fort Lauderdale Research and Education Center, University of Florida, Davie, FL, USA
| | - Xiangpeng Li
- School of Biological Sciences, Institute for Environmental Genomics, University of Oklahoma, Norman, OK, USA
| | | | - Xianhui Wan
- Department of Geosciences, Princeton University, Princeton, NJ, USA
| | - Britt Abrahamson
- Department of Civil and Environmental Engineering, University of Washington, Seattle, WA, USA
| | - Zachary Flinkstrom
- Department of Civil and Environmental Engineering, University of Washington, Seattle, WA, USA
| | - Baozhan Wang
- College of Life Sciences, Nanjing Agricultural University, Nanjing, Jiangsu, China
| | - Hanyan Li
- School of Biological Sciences, Institute for Environmental Genomics, University of Oklahoma, Norman, OK, USA
| | - Lei Hou
- School of Biological Sciences, Institute for Environmental Genomics, University of Oklahoma, Norman, OK, USA
- State Key Laboratory of Marine Environmental Science, College of the Environment and Ecology, Xiamen University, Xiamen, Fujian, China
| | - Qing Tao
- School of Biological Sciences, Institute for Environmental Genomics, University of Oklahoma, Norman, OK, USA
| | - Wyatt W Chlouber
- School of Biological Sciences, Institute for Environmental Genomics, University of Oklahoma, Norman, OK, USA
| | - Xin Sun
- Department of Ecology and Evolutionary Biology, Yale University, New Haven, CT, USA
| | - Michael Wells
- School of Biological Sciences, Institute for Environmental Genomics, University of Oklahoma, Norman, OK, USA
| | - Long Ngo
- School of Biological Sciences, Institute for Environmental Genomics, University of Oklahoma, Norman, OK, USA
| | - Kristopher A Hunt
- Department of Civil and Environmental Engineering, University of Washington, Seattle, WA, USA
| | - Hidetoshi Urakawa
- Department of Ecology and Environmental Studies, Florida Gulf Coast University, Fort Myers, FL, USA
| | - Xuanyu Tao
- School of Biological Sciences, Institute for Environmental Genomics, University of Oklahoma, Norman, OK, USA
| | - Dongyu Wang
- School of Biological Sciences, Institute for Environmental Genomics, University of Oklahoma, Norman, OK, USA
| | - Xiaoyuan Yan
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, China
| | - Dazhi Wang
- State Key Laboratory of Marine Environmental Science, College of the Environment and Ecology, Xiamen University, Xiamen, Fujian, China
| | - Chongle Pan
- School of Biological Sciences, Institute for Environmental Genomics, University of Oklahoma, Norman, OK, USA
| | - Peter K Weber
- Lawrence Livermore National Laboratory, Livermore, CA, USA
| | - Jiandong Jiang
- College of Life Sciences, Nanjing Agricultural University, Nanjing, Jiangsu, China
| | - Jizhong Zhou
- School of Biological Sciences, Institute for Environmental Genomics, University of Oklahoma, Norman, OK, USA
| | - Yao Zhang
- State Key Laboratory of Marine Environmental Science, College of Ocean and Earth Sciences, Xiamen University, Xiamen, Fujian, China
| | - David A Stahl
- Department of Civil and Environmental Engineering, University of Washington, Seattle, WA, USA
| | - Bess B Ward
- Department of Geosciences, Princeton University, Princeton, NJ, USA
| | - Xavier Mayali
- Lawrence Livermore National Laboratory, Livermore, CA, USA
| | - Willm Martens-Habbena
- Department of Microbiology and Cell Science, Fort Lauderdale Research and Education Center, University of Florida, Davie, FL, USA.
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13
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Müller MC, Lemaire ON, Kurth JM, Welte CU, Wagner T. Differences in regulation mechanisms of glutamine synthetases from methanogenic archaea unveiled by structural investigations. Commun Biol 2024; 7:111. [PMID: 38243071 PMCID: PMC10799026 DOI: 10.1038/s42003-023-05726-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Accepted: 12/19/2023] [Indexed: 01/21/2024] Open
Abstract
Glutamine synthetases (GS) catalyze the ATP-dependent ammonium assimilation, the initial step of nitrogen acquisition that must be under tight control to fit cellular needs. While their catalytic mechanisms and regulations are well-characterized in bacteria and eukaryotes, only limited knowledge exists in archaea. Here, we solved two archaeal GS structures and unveiled unexpected differences in their regulatory mechanisms. GS from Methanothermococcus thermolithotrophicus is inactive in its resting state and switched on by 2-oxoglutarate, a sensor of cellular nitrogen deficiency. The enzyme activation overlays remarkably well with the reported cellular concentration for 2-oxoglutarate. Its binding to an allosteric pocket reconfigures the active site through long-range conformational changes. The homolog from Methermicoccus shengliensis does not harbor the 2-oxoglutarate binding motif and, consequently, is 2-oxoglutarate insensitive. Instead, it is directly feedback-inhibited through glutamine recognition by the catalytic Asp50'-loop, a mechanism common to bacterial homologs, but absent in M. thermolithotrophicus due to residue substitution. Analyses of residue conservation in archaeal GS suggest that both regulations are widespread and not mutually exclusive. While the effectors and their binding sites are surprisingly different, the molecular mechanisms underlying their mode of action on GS activity operate on the same molecular determinants in the active site.
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Affiliation(s)
- Marie-Caroline Müller
- Microbial Metabolism Research Group, Max Planck Institute for Marine Microbiology, Celsiusstraße 1, 28359, Bremen, Germany
| | - Olivier N Lemaire
- Microbial Metabolism Research Group, Max Planck Institute for Marine Microbiology, Celsiusstraße 1, 28359, Bremen, Germany
| | - Julia M Kurth
- Department of Microbiology, Radboud Institute for Biological and Environmental Sciences, Radboud University, Heyendaalseweg 135, 6525 AJ, Nijmegen, The Netherlands
- Microcosm Earth Center, Philipps-University Marburg and Max Planck Institute for Terrestrial Microbiology, Hans-Meerwein-Str. 4, 35032, Marburg, Germany
| | - Cornelia U Welte
- Department of Microbiology, Radboud Institute for Biological and Environmental Sciences, Radboud University, Heyendaalseweg 135, 6525 AJ, Nijmegen, The Netherlands
| | - Tristan Wagner
- Microbial Metabolism Research Group, Max Planck Institute for Marine Microbiology, Celsiusstraße 1, 28359, Bremen, Germany.
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14
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Habenicht T, Weidenbach K, Velazquez-Campoy A, Buey RM, Balsera M, Schmitz RA. Small protein mediates inhibition of ammonium transport in Methanosarcina mazei-an ancient mechanism? Microbiol Spectr 2023; 11:e0281123. [PMID: 37909787 PMCID: PMC10714827 DOI: 10.1128/spectrum.02811-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2023] [Accepted: 09/29/2023] [Indexed: 11/03/2023] Open
Abstract
IMPORTANCE Small proteins containing fewer than 70 amino acids, which were previously disregarded due to computational prediction and biochemical detection challenges, have gained increased attention in the scientific community in recent years. However, the number of functionally characterized small proteins, especially in archaea, is still limited. Here, by using biochemical and genetic approaches, we demonstrate a crucial role of the small protein sP36 in the nitrogen metabolism of M. mazei, which modulates the ammonium transporter AmtB1 according to nitrogen availability. This modulation might represent an ancient archaeal mechanism of AmtB1 inhibition, in contrast to the well-studied uridylylation-dependent regulation in bacteria.
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Affiliation(s)
- Tim Habenicht
- Institut für allgemeine Mikrobiologie, Christian-Albrechts-Universität zu Kiel, Kiel, Germany
| | - Katrin Weidenbach
- Institut für allgemeine Mikrobiologie, Christian-Albrechts-Universität zu Kiel, Kiel, Germany
| | - Adrian Velazquez-Campoy
- Institute of Biocomputation and Physics of Complex Systems (BIFI), Universidad de Zaragoza, Zaragoza, Spain
- Departamento de Bioquímica y Biología Molecular y Celular, Universidad de Zaragoza, Zaragoza, Spain
- Instituto de Investigaciones Sanitarias de Aragón (IIS Aragón), Zaragoza, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBEREHD), Madrid, Spain
| | - Ruben M. Buey
- Departamento de Microbiología y Genética, Universidad de Salamanca, Salamanca, Spain
| | - Monica Balsera
- Instituto de Recursos Naturales y Agrobiología de Salamanca, Spanish National Research Council (IRNASA-CSIC), Salamanca, Spain
| | - Ruth A. Schmitz
- Institut für allgemeine Mikrobiologie, Christian-Albrechts-Universität zu Kiel, Kiel, Germany
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15
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Turk-Kubo KA, Gradoville MR, Cheung S, Cornejo-Castillo FM, Harding KJ, Morando M, Mills M, Zehr JP. Non-cyanobacterial diazotrophs: global diversity, distribution, ecophysiology, and activity in marine waters. FEMS Microbiol Rev 2023; 47:fuac046. [PMID: 36416813 PMCID: PMC10719068 DOI: 10.1093/femsre/fuac046] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Revised: 09/15/2022] [Accepted: 11/17/2022] [Indexed: 12/17/2023] Open
Abstract
Biological dinitrogen (N2) fixation supplies nitrogen to the oceans, supporting primary productivity, and is carried out by some bacteria and archaea referred to as diazotrophs. Cyanobacteria are conventionally considered to be the major contributors to marine N2 fixation, but non-cyanobacterial diazotrophs (NCDs) have been shown to be distributed throughout ocean ecosystems. However, the biogeochemical significance of marine NCDs has not been demonstrated. This review synthesizes multiple datasets, drawing from cultivation-independent molecular techniques and data from extensive oceanic expeditions, to provide a comprehensive view into the diversity, biogeography, ecophysiology, and activity of marine NCDs. A NCD nifH gene catalog was compiled containing sequences from both PCR-based and PCR-free methods, identifying taxa for future studies. NCD abundances from a novel database of NCD nifH-based abundances were colocalized with environmental data, unveiling distinct distributions and environmental drivers of individual taxa. Mechanisms that NCDs may use to fuel and regulate N2 fixation in response to oxygen and fixed nitrogen availability are discussed, based on a metabolic analysis of recently available Tara Oceans expedition data. The integration of multiple datasets provides a new perspective that enhances understanding of the biology, ecology, and biogeography of marine NCDs and provides tools and directions for future research.
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Affiliation(s)
- Kendra A Turk-Kubo
- Ocean Sciences Department, University of California, Santa Cruz, 1156 High Street, Santa Cruz, CA 95064, United States
| | - Mary R Gradoville
- Ocean Sciences Department, University of California, Santa Cruz, 1156 High Street, Santa Cruz, CA 95064, United States
- Columbia River Inter-Tribal Fish Commission, Portland, OR, United States
| | - Shunyan Cheung
- Ocean Sciences Department, University of California, Santa Cruz, 1156 High Street, Santa Cruz, CA 95064, United States
| | - Francisco M Cornejo-Castillo
- Ocean Sciences Department, University of California, Santa Cruz, 1156 High Street, Santa Cruz, CA 95064, United States
- Department of Marine Biology and Oceanography, Institute of Marine Sciences (ICM-CSIC), Pg. Marítim Barceloneta, 37-49 08003 Barcelona, Spain
| | - Katie J Harding
- Ocean Sciences Department, University of California, Santa Cruz, 1156 High Street, Santa Cruz, CA 95064, United States
- Marine Biology Research Division, Scripps Institute of Oceanography, 9500 Gilman Drive, La Jolla, CA 92093, United States
| | - Michael Morando
- Ocean Sciences Department, University of California, Santa Cruz, 1156 High Street, Santa Cruz, CA 95064, United States
| | - Matthew Mills
- Department of Earth System Science, Stanford University, 473 Via Ortega, Stanford, CA 94305, United States
| | - Jonathan P Zehr
- Ocean Sciences Department, University of California, Santa Cruz, 1156 High Street, Santa Cruz, CA 95064, United States
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16
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Sieradzki ET, Nuccio EE, Pett-Ridge J, Firestone MK. Rhizosphere and detritusphere habitats modulate expression of soil N-cycling genes during plant development. mSystems 2023; 8:e0031523. [PMID: 37754554 PMCID: PMC10654102 DOI: 10.1128/msystems.00315-23] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Accepted: 08/07/2023] [Indexed: 09/28/2023] Open
Abstract
IMPORTANCE Plant roots modulate microbial nitrogen (N) cycling by regulating the supply of root-derived carbon and nitrogen uptake. These differences in resource availability cause distinct micro-habitats to develop: soil near living roots, decaying roots, near both, or outside the direct influence of roots. While many environmental factors and genes control the microbial processes involved in the nitrogen cycle, most research has focused on single genes and pathways, neglecting the interactive effects these pathways have on each other. The processes controlled by these pathways determine consumption and production of N by soil microorganisms. We followed the expression of N-cycling genes in four soil microhabitats over a period of active root growth for an annual grass. We found that the presence of root litter and living roots significantly altered gene expression involved in multiple nitrogen pathways, as well as tradeoffs between pathways, which ultimately regulate N availability to plants.
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Affiliation(s)
- Ella T. Sieradzki
- Department of Environmental Science, Policy and Management, University of California Berkeley, Berkeley, California, USA
| | - Erin E. Nuccio
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, California, USA
| | - Jennifer Pett-Ridge
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, California, USA
- Life & Environmental Sciences Department, UC Merced, Merced, California, USA
- Innovative Genomics Institute, UC Berkeley, Berkeley, California, USA
| | - Mary K. Firestone
- Department of Environmental Science, Policy and Management, University of California Berkeley, Berkeley, California, USA
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17
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North H, McLaughlin M, Fiebig A, Crosson S. The Caulobacter NtrB-NtrC two-component system bridges nitrogen assimilation and cell development. J Bacteriol 2023; 205:e0018123. [PMID: 37791753 PMCID: PMC10601693 DOI: 10.1128/jb.00181-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Accepted: 09/03/2023] [Indexed: 10/05/2023] Open
Abstract
A suite of molecular sensory systems enables Caulobacter to control growth, development, and reproduction in response to levels of essential elements. The bacterial enhancer-binding protein (bEBP) NtrC and its cognate sensor histidine kinase, NtrB, are key regulators of nitrogen assimilation in many bacteria, but their roles in Caulobacter metabolism and development are not well defined. Notably, Caulobacter NtrC is an unconventional bEBP that lacks the σ54-interacting loop commonly known as the GAFTGA motif. Here we show that deletion of Caulobacter crescentus ntrC slows cell growth in complex medium and that ntrB and ntrC are essential when ammonium is the sole nitrogen source due to their requirement for glutamine synthetase expression. Random transposition of a conserved IS3-family mobile genetic element frequently rescued the growth defect of ntrC mutant strains by restoring transcription of the glnBA operon, revealing a possible role for IS3 transposition in shaping the evolution of Caulobacter populations during nutrient limitation. We further identified dozens of direct NtrC-binding sites on the C. crescentus chromosome, with a large fraction located near genes involved in polysaccharide biosynthesis. The majority of binding sites align with those of the essential nucleoid-associated protein, GapR, or the cell cycle regulator, MucR1. NtrC is therefore predicted to directly impact the regulation of cell cycle and cell development. Indeed, loss of NtrC function led to elongated polar stalks and elevated synthesis of cell envelope polysaccharides. This study establishes regulatory connections between NtrC, nitrogen metabolism, polar morphogenesis, and envelope polysaccharide synthesis in Caulobacter. IMPORTANCE Bacteria balance cellular processes with the availability of nutrients in their environment. The NtrB-NtrC two-component signaling system is responsible for controlling nitrogen assimilation in many bacteria. We have characterized the effect of ntrB and ntrC deletion on Caulobacter growth and development and uncovered a role for spontaneous IS element transposition in the rescue of transcriptional and nutritional deficiencies caused by ntrC mutation. We further defined the regulon of Caulobacter NtrC, a bacterial enhancer-binding protein, and demonstrate that it shares specific binding sites with essential proteins involved in cell cycle regulation and chromosome organization. Our work provides a comprehensive view of transcriptional regulation mediated by a distinctive NtrC protein, establishing its connection to nitrogen assimilation and developmental processes in Caulobacter.
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Affiliation(s)
- Hunter North
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan, USA
| | - Maeve McLaughlin
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan, USA
| | - Aretha Fiebig
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan, USA
| | - Sean Crosson
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan, USA
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18
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Flanagan LM, Horton JS, Taylor TB. Mutational hotspots lead to robust but suboptimal adaptive outcomes in certain environments. MICROBIOLOGY (READING, ENGLAND) 2023; 169:001395. [PMID: 37815519 PMCID: PMC10634368 DOI: 10.1099/mic.0.001395] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2023] [Accepted: 09/19/2023] [Indexed: 10/11/2023]
Abstract
The observed mutational spectrum of adaptive outcomes can be constrained by many factors. For example, mutational biases can narrow the observed spectrum by increasing the rate of mutation at isolated sites in the genome. In contrast, complex environments can shift the observed spectrum by defining fitness consequences of mutational routes. We investigate the impact of different nutrient environments on the evolution of motility in Pseudomonas fluorescens Pf0-2x (an engineered non-motile derivative of Pf0-1) in the presence and absence of a strong mutational hotspot. Previous work has shown that this mutational hotspot can be built and broken via six silent mutations, which provide rapid access to a mutation that rescues swimming motility and confers the strongest swimming phenotype in specific environments. Here, we evolved a hotspot and non-hotspot variant strain of Pf0-2x for motility under nutrient-rich (LB) and nutrient-limiting (M9) environmental conditions. We observed the hotspot strain consistently evolved faster across all environmental conditions and its mutational spectrum was robust to environmental differences. However, the non-hotspot strain had a distinct mutational spectrum that changed depending on the nutrient environment. Interestingly, while alternative adaptive mutations in nutrient-rich environments were equal to, or less effective than, the hotspot mutation, the majority of these mutations in nutrient-limited conditions produced superior swimmers. Our competition experiments mirrored these findings, underscoring the role of environment in defining both the mutational spectrum and the associated phenotype strength. This indicates that while mutational hotspots working in concert with natural selection can speed up access to robust adaptive mutations (which can provide a competitive advantage in evolving populations), they can limit exploration of the mutational landscape, restricting access to potentially stronger phenotypes in specific environments.
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Affiliation(s)
| | - James S. Horton
- Department of Life Sciences, University of Bath, Bath, BA2 7AY, UK
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19
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Chanderban M, Hill CA, Dhamad AE, Lessner DJ. Expression of V-nitrogenase and Fe-nitrogenase in Methanosarcina acetivorans is controlled by molybdenum, fixed nitrogen, and the expression of Mo-nitrogenase. Appl Environ Microbiol 2023; 89:e0103323. [PMID: 37695043 PMCID: PMC10537573 DOI: 10.1128/aem.01033-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2023] [Accepted: 07/07/2023] [Indexed: 09/12/2023] Open
Abstract
All nitrogen-fixing bacteria and archaea (diazotrophs) use molybdenum (Mo) nitrogenase to reduce dinitrogen (N2) to ammonia, with some also containing vanadium (V) and iron-only (Fe) nitrogenases that lack Mo. Among diazotrophs, the regulation and usage of the alternative V-nitrogenase and Fe-nitrogenase in methanogens are largely unknown. Methanosarcina acetivorans contains nif, vnf, and anf gene clusters encoding putative Mo-nitrogenase, V-nitrogenase, and Fe-nitrogenase, respectively. This study investigated nitrogenase expression and growth by M. acetivorans in response to fixed nitrogen, Mo/V availability, and CRISPRi repression of the nif, vnf, and/or anf gene clusters. The availability of Mo and V significantly affected growth of M. acetivorans with N2 but not with NH4Cl. M. acetivorans exhibited the fastest growth rate and highest cell yield during growth with N2 in medium containing Mo, and the slowest growth in medium lacking Mo and V. qPCR analysis revealed the transcription of the nif operon is only moderately affected by depletion of fixed nitrogen and Mo, whereas vnf and anf transcription increased significantly when fixed nitrogen and Mo were depleted, with removal of Mo being key. Immunoblot analysis revealed Mo-nitrogenase is detected when fixed nitrogen is depleted regardless of Mo availability, while V-nitrogenase and Fe-nitrogenase are detected only in the absence of fixed nitrogen and Mo. CRISPRi repression studies revealed that V-nitrogenase and/or Fe-nitrogenase are required for Mo-independent diazotrophy, and unexpectedly that the expression of Mo-nitrogenase is also required. These results reveal that alternative nitrogenase production in M. acetivorans is tightly controlled and dependent on Mo-nitrogenase expression. IMPORTANCE Methanogens and closely related methanotrophs are the only archaea known or predicted to possess nitrogenase. Methanogens play critical roles in both the global biological nitrogen and carbon cycles. Moreover, methanogens are an ancient microbial lineage and nitrogenase likely originated in methanogens. An understanding of the usage and properties of nitrogenases in methanogens can provide new insight into the evolution of nitrogen fixation and aid in the development nitrogenase-based biotechnology. This study provides the first evidence that a methanogen can produce all three forms of nitrogenases, including simultaneously. The results reveal components of Mo-nitrogenase regulate or are needed to produce V-nitrogenase and Fe-nitrogenase in methanogens, a result not seen in bacteria. Overall, this study provides a foundation to understand the assembly, regulation, and activity of the alternative nitrogenases in methanogens.
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Affiliation(s)
- Melissa Chanderban
- Department of Biological Sciences, University of Arkansas-Fayetteville, Fayetteville, Arkansas, USA
| | - Christopher A. Hill
- Department of Biological Sciences, University of Arkansas-Fayetteville, Fayetteville, Arkansas, USA
| | - Ahmed E. Dhamad
- Department of Biological Sciences, University of Arkansas-Fayetteville, Fayetteville, Arkansas, USA
- Department of Biological Sciences, Wasit University, Wasit, Iraq
| | - Daniel J. Lessner
- Department of Biological Sciences, University of Arkansas-Fayetteville, Fayetteville, Arkansas, USA
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20
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North H, McLaughlin M, Fiebig A, Crosson S. The Caulobacter NtrB-NtrC two-component system bridges nitrogen assimilation and cell development. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.06.06.543975. [PMID: 37333394 PMCID: PMC10274813 DOI: 10.1101/2023.06.06.543975] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/20/2023]
Abstract
A suite of molecular sensory systems enables Caulobacter to control growth, development, and reproduction in response to levels of essential elements. The bacterial enhancer binding protein (bEBP) NtrC, and its cognate sensor histidine kinase NtrB, are key regulators of nitrogen assimilation in many bacteria, but their roles in Caulobacter metabolism and development are not well defined. Notably, Caulobacter NtrC is an unconventional bEBP that lacks the σ54-interacting loop commonly known as the GAFTGA motif. Here we show that deletion of C. crescentus ntrC slows cell growth in complex medium, and that ntrB and ntrC are essential when ammonium is the sole nitrogen source due to their requirement for glutamine synthetase (glnA) expression. Random transposition of a conserved IS3-family mobile genetic element frequently rescued the growth defect of ntrC mutant strains by restoring transcription of the glnBA operon, revealing a possible role for IS3 transposition in shaping the evolution of Caulobacter populations during nutrient limitation. We further identified dozens of direct NtrC binding sites on the C. crescentus chromosome, with a large fraction located near genes involved in polysaccharide biosynthesis. The majority of binding sites align with those of the essential nucleoid associated protein, GapR, or the cell cycle regulator, MucR1. NtrC is therefore predicted to directly impact the regulation of cell cycle and cell development. Indeed, loss of NtrC function led to elongated polar stalks and elevated synthesis of cell envelope polysaccharides. This study establishes regulatory connections between NtrC, nitrogen metabolism, polar morphogenesis, and envelope polysaccharide synthesis in Caulobacter .
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Affiliation(s)
- Hunter North
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan USA
| | - Maeve McLaughlin
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan USA
| | - Aretha Fiebig
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan USA
| | - Sean Crosson
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan USA
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21
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Vlasova V, Lapina T, Statinov V, Ermilova E. N-Acetyl-L-glutamate Kinase of Chlamydomonas reinhardtii: In Vivo Regulation by PII Protein and Beyond. Int J Mol Sci 2023; 24:12873. [PMID: 37629055 PMCID: PMC10454706 DOI: 10.3390/ijms241612873] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2023] [Revised: 08/10/2023] [Accepted: 08/13/2023] [Indexed: 08/27/2023] Open
Abstract
N-Acetyl-L-glutamate kinase (NAGK) catalyzes the rate-limiting step in the ornithine/arginine biosynthesis pathway in eukaryotic and bacterial oxygenic phototrophs. NAGK is the most highly conserved target of the PII signal transduction protein in Cyanobacteria and Archaeplastida (red algae and Chlorophyta). However, there is still much to be learned about how NAGK is regulated in vivo. The use of unicellular green alga Chlamydomonas reinhardtii as a model system has already been instrumental in identifying several key regulation mechanisms that control nitrogen (N) metabolism. With a combination of molecular-genetic and biochemical approaches, we show the existence of the complex CrNAGK control at the transcriptional level, which is dependent on N source and N availability. In growing cells, CrNAGK requires CrPII to properly sense the feedback inhibitor arginine. Moreover, we provide primary evidence that CrPII is only partly responsible for regulating CrNAGK activity to adapt to changing nutritional conditions. Collectively, our results suggest that in vivo CrNAGK is tuned at the transcriptional and post-translational levels, and CrPII and additional as yet unknown factor(s) are integral parts of this regulation.
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Affiliation(s)
| | | | | | - Elena Ermilova
- Biological Faculty, Saint-Petersburg State University, 199034 Saint-Petersburg, Russia; (V.V.); (T.L.); (V.S.)
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22
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Sun Y, Zhang Y, Zhao T, Luan Y, Wang Y, Yang C, Shen B, Huang X, Li G, Zhao S, Zhao G, Wang Q. Acetylation coordinates the crosstalk between carbon metabolism and ammonium assimilation in Salmonella enterica. EMBO J 2023; 42:e112333. [PMID: 37183585 PMCID: PMC10308350 DOI: 10.15252/embj.2022112333] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2022] [Revised: 02/21/2023] [Accepted: 04/28/2023] [Indexed: 05/16/2023] Open
Abstract
Enteric bacteria use up to 15% of their cellular energy for ammonium assimilation via glutamine synthetase (GS)/glutamate synthase (GOGAT) and glutamate dehydrogenase (GDH) in response to varying ammonium availability. However, the sensory mechanisms for effective and appropriate coordination between carbon metabolism and ammonium assimilation have not been fully elucidated. Here, we report that in Salmonella enterica, carbon metabolism coordinates the activities of GS/GDH via functionally reversible protein lysine acetylation. Glucose promotes Pat acetyltransferase-mediated acetylation and activation of adenylylated GS. Simultaneously, glucose induces GDH acetylation to inactivate the enzyme by impeding its catalytic centre, which is reversed upon GDH deacetylation by deacetylase CobB. Molecular dynamics (MD) simulations indicate that adenylylation is required for acetylation-dependent activation of GS. We show that acetylation and deacetylation occur within minutes of "glucose shock" to promptly adapt to ammonium/carbon variation and finely balance glutamine/glutamate synthesis. Finally, in a mouse infection model, reduced S. enterica growth caused by the expression of adenylylation-mimetic GS is rescued by acetylation-mimicking mutations. Thus, glucose-driven acetylation integrates signals from ammonium assimilation and carbon metabolism to fine-tune bacterial growth control.
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Affiliation(s)
- Yunwei Sun
- Department of Gastroenterology of Ruijin Hospital, Shanghai Institute of ImmunologyShanghai Jiao Tong University School of MedicineShanghaiChina
| | - Yuebin Zhang
- Laboratory of Molecular Modeling and Design, State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical PhysicsChinese Academy of SciencesDalianChina
| | - Tingting Zhao
- Department of Gastroenterology of Ruijin Hospital, Shanghai Institute of ImmunologyShanghai Jiao Tong University School of MedicineShanghaiChina
| | - Yi Luan
- Department of Pharmacology, Vascular Biology and Therapeutic ProgramYale University School of MedicineNew HavenCTUSA
| | - Ying Wang
- Department of Gastroenterology of Ruijin Hospital, Shanghai Institute of ImmunologyShanghai Jiao Tong University School of MedicineShanghaiChina
| | - Chen Yang
- CAS‐Key Laboratory of Synthetic Biology, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological SciencesChinese Academy of SciencesShanghaiChina
| | - Bo Shen
- Department of Gastroenterology of Ruijin Hospital, Shanghai Institute of ImmunologyShanghai Jiao Tong University School of MedicineShanghaiChina
| | - Xi Huang
- Department of Gastroenterology of Ruijin Hospital, Shanghai Institute of ImmunologyShanghai Jiao Tong University School of MedicineShanghaiChina
| | - Guohui Li
- Laboratory of Molecular Modeling and Design, State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical PhysicsChinese Academy of SciencesDalianChina
| | - Shimin Zhao
- State Key Lab of Genetic Engineering & Institutes of Biomedical SciencesFudan UniversityShanghaiChina
- Department of Microbiology and Microbial Engineering, School of Life SciencesFudan UniversityShanghaiChina
- Collaborative Innovation Center for Biotherapy, West China HospitalSichuan UniversityChengduChina
| | - Guo‐ping Zhao
- CAS‐Key Laboratory of Synthetic Biology, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological SciencesChinese Academy of SciencesShanghaiChina
- State Key Lab of Genetic Engineering & Institutes of Biomedical SciencesFudan UniversityShanghaiChina
- Department of Microbiology and Microbial Engineering, School of Life SciencesFudan UniversityShanghaiChina
- Shanghai‐MOST Key Laboratory of Disease and Health GenomicsChinese National Human Genome Center at ShanghaiShanghaiChina
- Department of Microbiology and Li KaShing Institute of Health SciencesThe Chinese University of Hong Kong, Prince of Wales HospitalShatin, New Territories, Hong Kong SARChina
| | - Qijun Wang
- Department of Gastroenterology of Ruijin Hospital, Shanghai Institute of ImmunologyShanghai Jiao Tong University School of MedicineShanghaiChina
- Department of Pharmacology, Vascular Biology and Therapeutic ProgramYale University School of MedicineNew HavenCTUSA
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23
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Tian J, Yang Y, Du X, Xu W, Zhu B, Huang Y, Ye Y, Zhao Y, Li Y. Effects of dietary soluble β-1,3-glucan on the growth performance, antioxidant status, and immune response of the river prawn (Macrobrachium nipponense). FISH & SHELLFISH IMMUNOLOGY 2023; 138:108848. [PMID: 37230308 DOI: 10.1016/j.fsi.2023.108848] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Revised: 05/18/2023] [Accepted: 05/23/2023] [Indexed: 05/27/2023]
Abstract
The effects of dietary β-1,3-glucan on the growth performance, body composition, hepatopancreas tissue structure, antioxidant activities, and immune response of the river prawn (Macrobrachium nipponense) were investigated. In total, 900 juvenile prawns were fed one of five diets with different contents of β-1,3-glucan (0%, 0.1%, 0.2%, and 1.0%) or 0.2% curdlan for 6 weeks. The growth rate, weight gain rate, specific growth rate, specific weight gain rate, condition factor, and hepatosomatic index of juvenile prawns fed 0.2% β-1,3-glucan were significantly higher than those fed 0% β-1,3-glucan and 0.2% curdlan (p < 0.05). The whole-body crude lipid content of prawns supplemented with curdlan and β-1,3-glucan was significantly higher than that of the control group (p < 0.05). The antioxidant and immune enzyme activities of superoxide dismutase (SOD), total antioxidant capacity (T-AOC), catalase (CAT), lysozyme (LZM), phenoloxidase (PO), acid phosphatase (ACP), and alkaline phosphatase (AKP) in the hepatopancreas of juvenile prawns fed 0.2% β-1,3-glucan were significantly higher than those of the control and 0.2% curdlan groups (p < 0.05), and tended to increase and then decrease with increasing dietary β-1,3-glucan. The highest malondialdehyde (MDA) content was observed in juvenile prawns without β-1,3-glucan supplementation. The results of real-time quantitative PCR indicated that dietary β-1,3-glucan promoted expression of antioxidant and immune-related genes. Binomial fit analysis of weight gain rate and specific weight gain rate showed that the optimum β-1,3-glucan requirement of juvenile prawns was 0.550%-0.553%. We found that suitable dietary β-1,3-glucan improved juvenile prawns growth performance, antioxidant capacity, and non-specific immunity, which provide reference for shrimp healthy culture.
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Affiliation(s)
- Jiangtao Tian
- School of Life Science, East China Normal University, Shanghai, 200241, China
| | - Ying Yang
- School of Life Science, East China Normal University, Shanghai, 200241, China
| | - Xinglin Du
- School of Life Science, East China Normal University, Shanghai, 200241, China
| | - Wenyue Xu
- School of Life Science, East China Normal University, Shanghai, 200241, China
| | - Bihong Zhu
- School of Life Science, East China Normal University, Shanghai, 200241, China
| | - Yizhou Huang
- School of Life Science, East China Normal University, Shanghai, 200241, China
| | - Yucong Ye
- School of Life Science, East China Normal University, Shanghai, 200241, China
| | - Yunlong Zhao
- School of Life Science, East China Normal University, Shanghai, 200241, China; State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai, 200241, China.
| | - Yiming Li
- Fishery Machinery and Instrument Research Institute, Chinese Academy of Fisheries Sciences, Shanghai, 200092, China.
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24
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Xu Y, Ma S, Huang Z, Wang L, Raza SHA, Wang Z. Nitrogen metabolism in mycobacteria: the key genes and targeted antimicrobials. Front Microbiol 2023; 14:1149041. [PMID: 37275154 PMCID: PMC10232911 DOI: 10.3389/fmicb.2023.1149041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Accepted: 05/05/2023] [Indexed: 06/07/2023] Open
Abstract
Nitrogen metabolism is an important physiological process that affects the survival and virulence of Mycobacterium tuberculosis. M. tuberculosis's utilization of nitrogen in the environment and its adaptation to the harsh environment of acid and low oxygen in macrophages are closely related to nitrogen metabolism. In addition, the dormancy state and drug resistance of M. tuberculosis are closely related to nitrogen metabolism. Although nitrogen metabolism is so important, limited research was performed on nitrogen metabolism as compared with carbon metabolism. M. tuberculosis can use a variety of inorganic or organic nitrogen sources, including ammonium salts, nitrate, glutamine, asparagine, etc. In these metabolic pathways, some enzymes encoded by key genes, such as GlnA1, AnsP2, etc, play important regulatory roles in the pathogenesis of TB. Although various small molecule inhibitors and drugs have been developed for different nitrogen metabolism processes, however, long-term validation is needed before their practical application. Most importantly, with the emergence of multidrug-resistant strains, eradication, and control of M. tuberculosis will still be very challenging.
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Affiliation(s)
- Yufan Xu
- Shanghai Collaborative Innovation Center of Agri-Seeds, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China
- Shanghai Key Laboratory of Veterinary Biotechnology, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China
| | - Shiwei Ma
- Shanghai Collaborative Innovation Center of Agri-Seeds, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China
- Shanghai Key Laboratory of Veterinary Biotechnology, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China
| | - Zixin Huang
- Shanghai Collaborative Innovation Center of Agri-Seeds, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China
- Shanghai Key Laboratory of Veterinary Biotechnology, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China
| | - Longlong Wang
- Shanghai Collaborative Innovation Center of Agri-Seeds, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China
- Shanghai Key Laboratory of Veterinary Biotechnology, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China
| | - Sayed Haidar Abbas Raza
- Guangdong Provincial Key Laboratory of Food Quality and Safety/Nation-Local Joint Engineering Research Center for Machining and Safety of Livestock and Poultry Products, South China Agricultural University, Guangzhou, China
| | - Zhe Wang
- Shanghai Collaborative Innovation Center of Agri-Seeds, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China
- Shanghai Key Laboratory of Veterinary Biotechnology, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China
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25
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Ortega AD. Real-Time Assessment of Intracellular Metabolites in Single Cells through RNA-Based Sensors. Biomolecules 2023; 13:biom13050765. [PMID: 37238635 DOI: 10.3390/biom13050765] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2023] [Revised: 04/24/2023] [Accepted: 04/26/2023] [Indexed: 05/28/2023] Open
Abstract
Quantification of the concentration of particular cellular metabolites reports on the actual utilization of metabolic pathways in physiological and pathological conditions. Metabolite concentration also constitutes the readout for screening cell factories in metabolic engineering. However, there are no direct approaches that allow for real-time assessment of the levels of intracellular metabolites in single cells. In recent years, the modular architecture of natural bacterial RNA riboswitches has inspired the design of genetically encoded synthetic RNA devices that convert the intracellular concentration of a metabolite into a quantitative fluorescent signal. These so-called RNA-based sensors are composed of a metabolite-binding RNA aptamer as the sensor domain, connected through an actuator segment to a signal-generating reporter domain. However, at present, the variety of available RNA-based sensors for intracellular metabolites is still very limited. Here, we go through natural mechanisms for metabolite sensing and regulation in cells across all kingdoms, focusing on those mediated by riboswitches. We review the design principles underlying currently developed RNA-based sensors and discuss the challenges that hindered the development of novel sensors and recent strategies to address them. We finish by introducing the current and potential applicability of synthetic RNA-based sensors for intracellular metabolites.
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Affiliation(s)
- Alvaro Darío Ortega
- Department of Cell Biology, Faculty of Biological Sciences, Complutense University of Madrid, 28040 Madrid, Spain
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26
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He J, Kang X, Wu J, Shao Z, Zhang Z, Wu Y, Yuan H, Zhao G, Wang J. Transcriptional Self-Regulation of the Master Nitrogen Regulator GlnR in Mycobacteria. J Bacteriol 2023; 205:e0047922. [PMID: 36943048 PMCID: PMC10127674 DOI: 10.1128/jb.00479-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Accepted: 02/27/2023] [Indexed: 03/23/2023] Open
Abstract
As a master nitrogen regulator in most actinomycetes, GlnR both governs central nitrogen metabolism and regulates many carbon, phosphate, and secondary metabolic pathways. To date, most studies have been focused on the GlnR regulon, while little is known about the transcriptional regulator for glnR itself. It has been observed that glnR transcription can be upregulated in Mycobacterium smegmatis under nitrogen-limited growth conditions; however, the detailed regulatory mechanism is still unclear. Here, we demonstrate that the glnR gene in M. smegmatis is transcriptionally activated by its product GlnR in response to nitrogen limitation. The precise GlnR binding site was successfully characterized in its promoter region using the electrophoretic mobility shift assay and the DNase I footprinting assay. Site mutagenesis and genetic analyses confirmed that the binding site was essential for in vivo self-activation of glnR transcription. Moreover, based on bioinformatic analyses, we discovered that most of the mycobacterial glnR promoter regions (144 out of 147) contain potential GlnR binding sites, and we subsequently proved that the purified M. smegmatis GlnR protein could specifically bind 16 promoter regions that represent 119 mycobacterial species, including Mycobacterium tuberculosis. Together, our findings not only elucidate the transcriptional self-regulation mechanism of glnR transcription in M. smegmatis but also indicate the ubiquity of the mechanism in other mycobacterial species. IMPORTANCE In actinomycetes, the nitrogen metabolism not only is essential for the construction of life macromolecules but also affects the biosynthesis of secondary metabolites and even virulence (e.g., Mycobacterium tuberculosis). The transcriptional regulation of genes involved in nitrogen metabolism has been thoroughly studied and involves the master nitrogen regulator GlnR. However, the transcriptional regulation of glnR itself remains elusive. Here, we demonstrated that GlnR functions as a transcriptional self-activator in response to nitrogen starvation in the fast-growing model Mycobacterium species Mycobacterium smegmatis. We further showed that this self-regulation mechanism could be widespread in other mycobacteria, which might be beneficial for those slow-growing mycobacteria to adapt to the nitrogen-starvation environments such as within human macrophages for M. tuberculosis.
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Affiliation(s)
- Juanmei He
- CAS Key Laboratory of Synthetic Biology, Centre of Excellence for Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Xiaoman Kang
- CAS Key Laboratory of Synthetic Biology, Centre of Excellence for Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Jiacheng Wu
- CAS Key Laboratory of Synthetic Biology, Centre of Excellence for Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Zhihui Shao
- CAS Key Laboratory of Synthetic Biology, Centre of Excellence for Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai, China
| | | | - Yuqian Wu
- Institute of Synthetic Biology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
| | - Hua Yuan
- College of Life Sciences, Shanghai Normal University, Shanghai, China
| | - Guoping Zhao
- CAS Key Laboratory of Synthetic Biology, Centre of Excellence for Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Jin Wang
- Department of Clinical Laboratory, Shenzhen Second People’s Hospital & Institute of Translational Medicine/the First Affiliated Hospital of Shenzhen University Health Science Center, Shenzhen, China
- Guangdong Provincial Key Laboratory of Systems Biology and Synthetic Biology for Urogenital Tumors, The First Affiliated Hospital of Shenzhen University, Shenzhen Second People’s Hospital (Shenzhen Institute of Translational Medicine), Shenzhen, China
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27
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Lü J, Wang S, Liu B, Song X. Spatiotemporal heterogeneity of nitrogen transformation potentials in a freshwater estuarine system. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 859:160335. [PMID: 36414069 DOI: 10.1016/j.scitotenv.2022.160335] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Revised: 10/31/2022] [Accepted: 11/16/2022] [Indexed: 06/16/2023]
Abstract
Under the influence of water diversion, the microbial community composition of estuarine waters and sediments might have complex spatiotemporal variations. Microbial interactions with N are significant for lake water quality. Therefore, the largest lake receiving seasonal water diversion in the North China Plain was selected as the study area. Based on 16S rRNA high-throughput sequencing and metagenomic sequencing techniques, this study analysed temporal (June-December) and spatial (estuary-pelagic zone) changes in the microbial community and functional gene composition of water and sediment. The results showed that the water microbial community composition had temporality, while sediment microbes had spatiality. The main causes of temporality in the aquatic microbial community were temperature and nitrate-N concentration, while those of sediment were flow velocity and N content. Additionally, there were complex interactions between microbial communities and N. In water, temporal variation in the relative abundance of N-related functional genes might have indirectly contributed to inorganic N composition in June (nitrite-N > ammonia-N > nitrate-N) and August (nitrite-N > nitrate-N > ammonia-N). High nitrate-N concentrations in December influenced the microbial community composition. In sediment, the estuary had higher N functional genes than the pelagic estuary, creating a relatively active N cycle and reducing total N levels in the estuary. This study revealed a potentially overlooked N sink and a flow velocity threshold that has great impacts on microbial community composition. This research contributes to a deeper understanding of the estuarine N cycle under the influence of water diversions, with implications for the calculation of global N balances and the management of lake water environments.
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Affiliation(s)
- Jiali Lü
- Key Laboratory of Agricultural Water Resources, Center for Agricultural Resources Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Shijiazhuang 050021, China; Sino-Danish College of University of Chinese Academy of Sciences, Beijing 101408, China; Sino-Danish Centre for Education and Research, Beijing 101408, China; Key Laboratory of Water Cycle & Related Land Surface Processes, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China; Department of Plant and Environmental Sciences, University of Copenhagen, Copenhagen 999017, Denmark
| | - Shiqin Wang
- Key Laboratory of Agricultural Water Resources, Center for Agricultural Resources Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Shijiazhuang 050021, China; Xiongan Institute of Innovation, Chinese Academy of Science, China.
| | - Binbin Liu
- Key Laboratory of Agricultural Water Resources, Center for Agricultural Resources Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Shijiazhuang 050021, China; Xiongan Institute of Innovation, Chinese Academy of Science, China
| | - Xianfang Song
- Sino-Danish College of University of Chinese Academy of Sciences, Beijing 101408, China; Sino-Danish Centre for Education and Research, Beijing 101408, China; Key Laboratory of Water Cycle & Related Land Surface Processes, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China
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28
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Ma T, Zhang Y, Yan C, Zhang C. Phenotypic and Genomic Difference among Four Botryosphaeria Pathogens in Chinese Hickory Trunk Canker. J Fungi (Basel) 2023; 9:204. [PMID: 36836318 PMCID: PMC9963396 DOI: 10.3390/jof9020204] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2023] [Revised: 01/25/2023] [Accepted: 01/31/2023] [Indexed: 02/09/2023] Open
Abstract
Botryosphaeria species are amongst the most widespread and important canker and dieback pathogens of trees worldwide, with B. dothidea as one of the most common Botryosphaeria species. However, the information related to the widespread incidence and aggressiveness of B. dothidea among various Botryosphaeria species causing trunk cankers is still poorly investigated. In this study, the metabolic phenotypic diversity and genomic differences of four Chinese hickory canker-related Botryosphaeria pathogens, including B. dothidea, B. qingyuanensis, B. fabicerciana, and B. corticis, were systematically studied to address the competitive fitness of B. dothidea. Large-scale screening of physiologic traits using a phenotypic MicroArray/OmniLog system (PMs) found B. dothidea has a broader spectrum of nitrogen source and greater tolerance toward osmotic pressure (sodium benzoate) and alkali stress among Botryosphaeria species. Moreover, the annotation of B. dothidea species-specific genomic information via a comparative genomics analysis found 143 B. dothidea species-specific genes that not only provides crucial cues in the prediction of B. dothidea species-specific function but also give a basis for the development of a B. dothidea molecular identification method. A species-specific primer set Bd_11F/Bd_11R has been designed based on the sequence of B. dothidea species-specific gene jg11 for the accurate identification of B. dothidea in disease diagnoses. Overall, this study deepens the understanding in the widespread incidence and aggressiveness of B. dothidea among various Botryosphaeria species, providing valuable clues to assist in trunk cankers management.
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Affiliation(s)
| | | | | | - Chuanqing Zhang
- Department of Plant Pathology, Zhejiang Agriculture and Forest University, Hangzhou 311300, China
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Genomic, probiotic, and metabolic potentials of Liquorilactobacillus nagelii AGA58, a novel bacteriocinogenic motile strain isolated from lactic acid-fermented shalgam. J Biosci Bioeng 2023; 135:34-43. [PMID: 36384719 DOI: 10.1016/j.jbiosc.2022.10.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Revised: 10/19/2022] [Accepted: 10/19/2022] [Indexed: 11/15/2022]
Abstract
This study aimed to perform genomic, probiotic, and metabolic characterization of a novel Liquorilactobacillus nagelii AGA58 isolated from a lactic acid-fermented shalgam beverage to understand its metabolic potentials and probiotic features. AGA58 is gram-positive, motile, catalase-negative and appears as short rods under the light-microscope. The AGA58 chromosome comprises a single linear chromosome of 2,294,635 bp that is predicted to carry 2135 coding sequences, including 45 tRNA genes, 3 mRNA, and 3 rRNA operons. The genome has a G+C content of 36.9%, including 55 pseudogenes and a single intact prophage. AGA58 is micro-anaerobic due to achieving a shorter doubling time and faster growth rate than micro-aerophilic conditions. It carries flagellar biosynthesis protein-encoding genes predicting motile behavior, which was confirmed with the in vitro motility test. AGA58 is an obligatory homofermentative lactobacillus that can ferment hexose sugars such as galactose, glucose, fructose, sucrose, mannose, N-acetyl glucosamine, maltose, and trehalose to lactate through glycolysis. No acid production from pentoses implies that five-carbon sugars are being utilized for purine and pyrimidine synthesis. Putative pyruvate metabolism revealed formate, malate, oxaloacetate, acetate, acetaldehyde, acetoin, and lactate forms from pyruvate. AGA58 is predicted to encode the LuxS gene and biosynthesis of class IIa and Blp family class-II bacteriocins suggesting this bacterium's antimicrobial potential, linked to antagonism tests that AGA58 can inhibit Escherichia coli ATCC 43895, Salmonellaenterica serovar Typhimurium ATCC 14028, and Klebsiellapneumonia ATCC 13883. Moreover, AGA58 is tolerant to acid and bile concentrations simulating the human gastrointestinal conditions depicting the probiotic potential of the organism as the first report in literature within the same species.
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Comparative Transcriptomics Sheds Light on Remodeling of Gene Expression during Diazotrophy in the Thermophilic Methanogen Methanothermococcus thermolithotrophicus. mBio 2022; 13:e0244322. [PMID: 36409126 PMCID: PMC9765008 DOI: 10.1128/mbio.02443-22] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Some marine thermophilic methanogens are able to perform energy-consuming nitrogen fixation despite deriving only little energy from hydrogenotrophic methanogenesis. We studied this process in Methanothermococcus thermolithotrophicus DSM 2095, a methanogenic archaeon of the order Methanococcales that contributes to the nitrogen pool in some marine environments. We successfully grew this archaeon under diazotrophic conditions in both batch and fermenter cultures, reaching the highest cell density reported so far. Diazotrophic growth depended strictly on molybdenum and, in contrast to other diazotrophs, was not inhibited by tungstate or vanadium. This suggests an elaborate control of metal uptake and a specific metal recognition system for the insertion into the nitrogenase cofactor. Differential transcriptomics of M. thermolithotrophicus grown under diazotrophic conditions with ammonium-fed cultures as controls revealed upregulation of the nitrogenase machinery, including chaperones, regulators, and molybdate importers, as well as simultaneous upregulation of an ammonium transporter and a putative pathway for nitrate and nitrite utilization. The organism thus employs multiple synergistic strategies for uptake of nitrogen nutrients during the early exponential growth phase without altering transcription levels for genes involved in methanogenesis. As a counterpart, genes coding for transcription and translation processes were downregulated, highlighting the maintenance of an intricate metabolic balance to deal with energy constraints and nutrient limitations imposed by diazotrophy. This switch in the metabolic balance included unexpected processes, such as upregulation of the CRISPR-Cas system, probably caused by drastic changes in transcription levels of putative mobile and virus-like elements. IMPORTANCE The thermophilic anaerobic archaeon M. thermolithotrophicus is a particularly suitable model organism to study the coupling of methanogenesis to diazotrophy. Likewise, its capability of simultaneously reducing N2 and CO2 into NH3 and CH4 with H2 makes it a viable target for biofuel production. We optimized M. thermolithotrophicus cultivation, resulting in considerably higher cell yields and enabling the successful establishment of N2-fixing bioreactors. Improved understanding of the N2 fixation process would provide novel insights into metabolic adaptations that allow this energy-limited extremophile to thrive under diazotrophy, for instance, by investigating its physiology and uncharacterized nitrogenase. We demonstrated that diazotrophic growth of M. thermolithotrophicus is exclusively dependent on molybdenum, and complementary transcriptomics corroborated the expression of the molybdenum nitrogenase system. Further analyses of differentially expressed genes during diazotrophy across three cultivation time points revealed insights into the response to nitrogen limitation and the coordination of core metabolic processes.
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Ngashangva N, Mukherjee PK, Sharma C, Kalita MC, Sarangthem I. Integrated genomics and proteomics analysis of Paenibacillus peoriae IBSD35 and insights into its antimicrobial characteristics. Sci Rep 2022; 12:18861. [PMID: 36344671 PMCID: PMC9640621 DOI: 10.1038/s41598-022-23613-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2022] [Accepted: 11/02/2022] [Indexed: 11/09/2022] Open
Abstract
Antimicrobial resistance has been developing fast and incurring a loss of human life, and there is a need for new antimicrobial agents. Naturally occurring antimicrobial peptides offer the characteristics to counter AMR because the resistance development is low or no resistance. Antimicrobial peptides from Paenibacillus peoriae IBSD35 cell-free supernatant were salted out and purified using chromatography and characterized with liquid chromatography-tandem-mass spectrometry. The extract has shown a high and broad spectrum of antimicrobial activity. Combining the strain IBSD35 genome sequence with its proteomic data enabled the prediction of biosynthetic gene clusters by connecting the peptide from LC-MS/MS data to the gene that encode. Antimicrobial peptide databases offered a platform for the effective search, prediction, and design of AMPs and expanded the studies on their isolation, structure elucidation, biological evaluation, and pathway engineering. The genome-based taxonomy and comparisons have shown that P. peoriae IBSD35 is closely related to Paenibacillus peoriae FSL J3-0120. P. peoriae IBSD35 harbored endophytic trait genes and nonribosomal peptide synthases biosynthetic gene clusters. The comparative genomics revealed evolutionary insights and facilitated the discovery of novel SMs using proteomics from the extract of P. peoriae IBSD35. It will increase the potential to find novel bio-molecules to counter AMR.
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Affiliation(s)
- Ng Ngashangva
- grid.464584.f0000 0004 0640 0101A National Institute of Department of Biotechnology, Institute of Bioresources and Sustainable Development (IBSD), Govt. of India, Takyelpat, Imphal, Manipur 795001 India
| | - Pulok K. Mukherjee
- grid.464584.f0000 0004 0640 0101A National Institute of Department of Biotechnology, Institute of Bioresources and Sustainable Development (IBSD), Govt. of India, Takyelpat, Imphal, Manipur 795001 India
| | - Chandradev Sharma
- grid.464584.f0000 0004 0640 0101A National Institute of Department of Biotechnology, Institute of Bioresources and Sustainable Development (IBSD), Govt. of India, Takyelpat, Imphal, Manipur 795001 India
| | - Mohan C. Kalita
- grid.411779.d0000 0001 2109 4622Department of Biotechnology, Gauhati University, Jalukbari, Guwahati, Assam 781014 India
| | - Indira Sarangthem
- grid.464584.f0000 0004 0640 0101A National Institute of Department of Biotechnology, Institute of Bioresources and Sustainable Development (IBSD), Govt. of India, Takyelpat, Imphal, Manipur 795001 India
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Walling LR, Kouse AB, Shabalina SA, Zhang H, Storz G. A 3' UTR-derived small RNA connecting nitrogen and carbon metabolism in enteric bacteria. Nucleic Acids Res 2022; 50:10093-10109. [PMID: 36062564 PMCID: PMC9508815 DOI: 10.1093/nar/gkac748] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2022] [Revised: 08/11/2022] [Accepted: 08/26/2022] [Indexed: 11/13/2022] Open
Abstract
Increasing numbers of small, regulatory RNAs (sRNAs) corresponding to 3' untranslated regions (UTR) are being discovered in bacteria. One such sRNA, denoted GlnZ, corresponds to the 3' UTR of the Escherichia coli glnA mRNA encoding glutamine synthetase. Several forms of GlnZ, processed from the glnA mRNA, are detected in cells growing with limiting ammonium. GlnZ levels are regulated transcriptionally by the NtrC transcription factor and post-transcriptionally by RNase III. Consistent with the expression, E. coli cells lacking glnZ show delayed outgrowth from nitrogen starvation compared to wild type cells. Transcriptome-wide RNA-RNA interactome datasets indicated that GlnZ binds to multiple target RNAs. Immunoblots and assays of fusions confirmed GlnZ-mediated repression of glnP and sucA, encoding proteins that contribute to glutamine transport and the citric acid cycle, respectively. Although the overall sequences of GlnZ from E. coli K-12, Enterohemorrhagic E. coli and Salmonella enterica have significant differences due to various sequence insertions, all forms of the sRNA were able to regulate the two targets characterized. Together our data show that GlnZ impacts growth of E. coli under low nitrogen conditions by modulating genes that affect carbon and nitrogen flux.
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Affiliation(s)
- Lauren R Walling
- Division of Molecular and Cellular Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, MD 20892-4417, USA
| | - Andrew B Kouse
- Division of Molecular and Cellular Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, MD 20892-4417, USA
| | - Svetlana A Shabalina
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD 20894, USA
| | - Hongen Zhang
- Bioinformatics and Scientific Programming Core, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, MD 20892-4417, USA
| | - Gisela Storz
- Division of Molecular and Cellular Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, MD 20892-4417, USA
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Duan H, He P, Zhang H, Shao L, Lü F. Metabolic Regulation of Mesophilic Methanosarcina barkeri to Ammonium Inhibition. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:8897-8907. [PMID: 35588324 DOI: 10.1021/acs.est.2c01212] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Undesirable ammonium concentrations can lead to unstable anaerobic digestion processes, and Methanosarcina spp. are the representative methanogens under inhibition. However, no known work seems to exist for directly exploring the detailed metabolic regulation of pure cultured representative Methanosarcina spp. to ammonium inhibition. We used transcriptomics and proteomics to profile the metabolic regulation of Methanosarcina barkeri to 1, 4, and 7 g N/L of total ammoniacal nitrogen (TAN), where free ammonia concentrations were between 1.5 and 36.1 mg N/L. At the initial stages of ammonium inhibition, the genes participating in the acquisition and assimilation of reduced nitrogen sources showed significant upregulation where the minimal fold change of gene transcription was about 2. Apart from nitrogen metabolism, the transcription of some genes in methanogenesis also significantly increased at the initial stages. For example, the genes encoding alternative heterodisulfide reductase subunits (HdrAB), energy-converting hydrogenase subunit (EchC), and methanophenazine-dependent hydrogenase subunits (VhtAC) were significantly upregulated by at least 2.05 times. For the element translocation at the initial stages, the genes participating in the uptake of ferrous iron, potassium ion, and molybdate were significantly upregulated with a minimal fold change of 2.10. As the cultivation proceeded, the gene encoding the cell division protein subunit (FtsH) was significantly upregulated by 13.0 times at 7 g N/L of TAN; meanwhile, an increment in OD600 was observed at the terminal sampling point of 7 g N/L of TAN. The present study explored the metabolic regulation of M. barkeri in stress response, protein synthesis, signal transduction, nitrogen metabolism, methanogenesis, and element translocation. The results would contribute to the understanding of the metabolic effects of ammonium inhibition on methanogens and have significant practical implication in inhibited anaerobic digestion.
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Affiliation(s)
- Haowen Duan
- State Key Laboratory of Pollution Control and Resource Reuse, Tongji University, Shanghai 200092, China
| | - Pinjing He
- Institute of Waste Treatment and Reclamation, Tongji University, Shanghai 200092, China
- Shanghai Multi-Source Solid Waste Collaborative Treatment and Energy Engineering Technology Research Center, Shanghai 200092, China
| | - Hua Zhang
- State Key Laboratory of Pollution Control and Resource Reuse, Tongji University, Shanghai 200092, China
- Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, China
| | - Liming Shao
- Institute of Waste Treatment and Reclamation, Tongji University, Shanghai 200092, China
| | - Fan Lü
- State Key Laboratory of Pollution Control and Resource Reuse, Tongji University, Shanghai 200092, China
- Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, China
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Du R, Gao D, Wang Y, Liu L, Cheng J, Liu J, Zhang XH, Yu M. Heterotrophic Sulfur Oxidation of Halomonas titanicae SOB56 and Its Habitat Adaptation to the Hydrothermal Environment. Front Microbiol 2022; 13:888833. [PMID: 35774465 PMCID: PMC9237845 DOI: 10.3389/fmicb.2022.888833] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2022] [Accepted: 05/24/2022] [Indexed: 11/23/2022] Open
Abstract
Halomonas bacteria are ubiquitous in global marine environments, however, their sulfur-oxidizing abilities and survival adaptations in hydrothermal environments are not well understood. In this study, we characterized the sulfur oxidation ability and metabolic mechanisms of Halomonas titanicae SOB56, which was isolated from the sediment of the Tangyin hydrothermal field in the Southern Okinawa Trough. Physiological characterizations showed that it is a heterotrophic sulfur-oxidizing bacterium that can oxidize thiosulfate to tetrathionate, with the Na2S2O3 degradation reaching 94.86%. Two potential thiosulfate dehydrogenase-related genes, tsdA and tsdB, were identified as encoding key catalytic enzymes, and their expression levels in strain SOB56 were significantly upregulated. Nine of fifteen examined Halomonas genomes possess TsdA- and TsdB-homologous proteins, whose amino acid sequences have two typical Cys-X2-Cys-His heme-binding regions. Moreover, the thiosulfate oxidation process in H. titanicae SOB56 might be regulated by quorum sensing, and autoinducer-2 synthesis protein LuxS was identified in its genome. Regarding the mechanisms underlying adaptation to hydrothermal environment, strain SOB56 was capable of forming biofilms and producing EPS. In addition, genes related to complete flagellum assembly system, various signal transduction histidine kinases, heavy metal transporters, anaerobic respiration, and variable osmotic stress regulation were also identified. Our results shed light on the potential functions of heterotrophic Halomonas bacteria in hydrothermal sulfur cycle and revealed possible adaptations for living at deep-sea hydrothermal fields by H. titanicae SOB56.
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Affiliation(s)
- Rui Du
- College of Marine Life Sciences, and Frontiers Science Center for Deep Ocean Multispheres and Earth System, Ocean University of China, Qingdao, China
- Laboratory for Marine Ecology and Environmental Science, Pilot National Laboratory for Marine Science and Technology, Qingdao, China
- Institute of Evolution and Marine Biodiversity, Ocean University of China, Qingdao, China
| | - Di Gao
- College of Marine Life Sciences, and Frontiers Science Center for Deep Ocean Multispheres and Earth System, Ocean University of China, Qingdao, China
| | - Yiting Wang
- College of Marine Life Sciences, and Frontiers Science Center for Deep Ocean Multispheres and Earth System, Ocean University of China, Qingdao, China
| | - Lijun Liu
- College of Marine Life Sciences, and Frontiers Science Center for Deep Ocean Multispheres and Earth System, Ocean University of China, Qingdao, China
| | - Jingguang Cheng
- College of Marine Life Sciences, and Frontiers Science Center for Deep Ocean Multispheres and Earth System, Ocean University of China, Qingdao, China
| | - Jiwen Liu
- College of Marine Life Sciences, and Frontiers Science Center for Deep Ocean Multispheres and Earth System, Ocean University of China, Qingdao, China
- Laboratory for Marine Ecology and Environmental Science, Pilot National Laboratory for Marine Science and Technology, Qingdao, China
- Institute of Evolution and Marine Biodiversity, Ocean University of China, Qingdao, China
| | - Xiao-Hua Zhang
- College of Marine Life Sciences, and Frontiers Science Center for Deep Ocean Multispheres and Earth System, Ocean University of China, Qingdao, China
- Laboratory for Marine Ecology and Environmental Science, Pilot National Laboratory for Marine Science and Technology, Qingdao, China
- Institute of Evolution and Marine Biodiversity, Ocean University of China, Qingdao, China
| | - Min Yu
- College of Marine Life Sciences, and Frontiers Science Center for Deep Ocean Multispheres and Earth System, Ocean University of China, Qingdao, China
- Laboratory for Marine Ecology and Environmental Science, Pilot National Laboratory for Marine Science and Technology, Qingdao, China
- Institute of Evolution and Marine Biodiversity, Ocean University of China, Qingdao, China
- *Correspondence: Min Yu,
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35
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Huang P, Chen S, Chiang W, Ho M, Wu K. Structural basis for the helical filament formation of Escherichia coli glutamine synthetase. Protein Sci 2022; 31:e4304. [PMID: 35481643 PMCID: PMC8996467 DOI: 10.1002/pro.4304] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Revised: 03/15/2022] [Accepted: 03/17/2022] [Indexed: 02/01/2023]
Abstract
Escherichia coli glutamine synthetase (EcGS) spontaneously forms a dodecamer that catalytically converts glutamate to glutamine. EcGS stacks with other dodecamers to create a filament-like polymer visible under transmission electron microscopy. Filamentous EcGS is induced by environmental metal ions. We used cryo-electron microscopy (cryo-EM) to decipher the structure of metal ion (nickel)-induced EcGS helical filament at a sub-3Å resolution. EcGS filament formation involves stacking of native dodecamers by chelating nickel ions to residues His5 and His13 in the first N-terminal helix (H1). His5 and His13 from paired parallel H1 helices provide salt bridges and hydrogen bonds to tightly stack two dodecamers. One subunit of the EcGS filament hosts two nickel ions, whereas the dodecameric interface and the ATP/Mg-binding site both host a nickel ion each. We reveal that upon adding glutamate or ATP for catalytic reactions, nickel-induced EcGS filament reverts to individual dodecamers. Such tunable filament formation is often associated with stress responses. Our results provide detailed structural information on the mechanism underlying reversible and tunable EcGS filament formation.
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Affiliation(s)
- Pei‐Chi Huang
- Institute of Biological ChemistryAcademia SinicaTaipeiTaiwan
- Department of ChemistryNational Taiwan Normal UniversityTaipeiTaiwan
| | - Shao‐Kang Chen
- Institute of Biological ChemistryAcademia SinicaTaipeiTaiwan
| | - Wei‐Hung Chiang
- Institute of Biological ChemistryAcademia SinicaTaipeiTaiwan
| | - Meng‐Ru Ho
- Institute of Biological ChemistryAcademia SinicaTaipeiTaiwan
| | - Kuen‐Phon Wu
- Institute of Biological ChemistryAcademia SinicaTaipeiTaiwan
- Institute of Biochemical ScienceCollege of Life Science, National Taiwan UniversityTaipeiTaiwan
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36
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Transition of Dephospho-DctD to the Transcriptionally Active State via Interaction with Dephospho-IIA
Glc. mBio 2022; 13:e0383921. [PMID: 35311533 PMCID: PMC9040800 DOI: 10.1128/mbio.03839-21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Exopolysaccharides (EPSs), biofilm-maturing components of Vibrio vulnificus, are abundantly produced when the expression of two major EPS gene clusters is activated by an enhancer-binding transcription factor, DctD2, whose expression and phosphorylation are induced by dicarboxylic acids. Surprisingly, when glucose was supplied to V. vulnificus, similar levels of expression of these clusters occurred, even in the absence of dicarboxylic acids. This glucose-dependent activation was also mediated by DctD2, whose expression was sequentially activated by the transcription regulator NtrC. Most DctD2 in cells grown without dicarboxylic acids was present in a dephosphorylated state, known as the transcriptionally inactive form. However, in the presence of glucose, a dephosphorylated component of the glucose-specific phosphotransferase system, d-IIAGlc, interacted with dephosphorylated DctD2 (d-DctD2). While d-DctD2 did not show any affinity to a DNA fragment containing the DctD-binding sequences, the complex of d-DctD2 and d-IIAGlc exhibited specific and efficient DNA binding, similar to the phosphorylated DctD2. The d-DctD2-mediated activation of the EPS gene clusters’ expression was not fully achieved in cells grown with mannose. Furthermore, the degrees of expression of the clusters under glycerol were less than those under mannose. This was caused by an antagonistic and competitive effect of GlpK, whose expression was increased by glycerol, in forming a complex with d-DctD2 by d-IIAGlc. The data demonstrate a novel regulatory pathway for V. vulnificus EPS biosynthesis and biofilm maturation in the presence of glucose, which is mediated by d-DctD2 through its transition to the transcriptionally active state by interacting with available d-IIAGlc.
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Zhong Z, Wang C, Zhang H, Mi J, Liang JB, Liao X, Wu Y, Wang Y. Sodium butyrate reduces ammonia emissions through glutamate metabolic pathways in cecal microorganisms of laying hens. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2022; 233:113299. [PMID: 35176673 DOI: 10.1016/j.ecoenv.2022.113299] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2021] [Revised: 01/25/2022] [Accepted: 02/07/2022] [Indexed: 06/14/2023]
Abstract
Ammonia emission is an important problem that needs to be solved in laying hen industries. Sodium butyrate (SB) is considered to have potential for reducing ammonia production because of its ability to improve nitrogen metabolism. In this in vitro fermentation study, we presented a correlation analysis of the metatranscriptome and metaproteome of lay hen cecal microorganisms, in order to identify important proteins and pathways involved in ammonia production reduction due to sodium butyrate supplementation. The results showed that sodium butyrate supplement decreased the production of ammonia by 26.22% as compared with the non-sodium butyrate supplementation (CK) group. The SB group exhibited a lower concentration of ammonium nitrogen (NH4+-N) and a decreased pH. Sodium butyrate promoted the uric acid concentration and lowered the uricase activity in the fermentation broth of laying hens cecal content. Notably, the 'alanine, aspartate and glutamate metabolism' category was more abundant in the SB group. The addition of sodium butyrate increased the expression of glutamate dehydrogenase (GDH) gene in cecal microbiota (e.g., Ruminococcus sp. and Bacteroides sp.) in vitro. The metaproteome analysis results showed that the expression of GDH with NADPH as coenzyme (NADPH-GDH) was up-regulated in cecal microbiota by sodium butyrate supplement. Our results indicate that sodium butyrate can affect glutamate metabolism through regulating the expression of glutamate dehydrogenase in cecal microorganisms, thereby reducing ammonia production. This study reveals that glutamate dehydrogenase-mediated glutamate metabolism play a key role in ammonia emission reduction in laying hen and provide theoretical basis for further developing ammonia production reduction approach.
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Affiliation(s)
- Zhikang Zhong
- College of Animal Science, National Engineering Research Center for Breeding Swine Industry, South China Agricultural University, Guangzhou 510642, China
| | - Chao Wang
- College of Animal Science, National Engineering Research Center for Breeding Swine Industry, South China Agricultural University, Guangzhou 510642, China
| | - Huaidan Zhang
- College of Animal Science, National Engineering Research Center for Breeding Swine Industry, South China Agricultural University, Guangzhou 510642, China
| | - Jiandui Mi
- College of Animal Science, National Engineering Research Center for Breeding Swine Industry, South China Agricultural University, Guangzhou 510642, China
| | - Juan Boo Liang
- Institute of Tropical Agriculture, University Putra Malaysia, Serdang 43400, Malaysia
| | - Xindi Liao
- College of Animal Science, National Engineering Research Center for Breeding Swine Industry, South China Agricultural University, Guangzhou 510642, China
| | - Yinbao Wu
- College of Animal Science, National Engineering Research Center for Breeding Swine Industry, South China Agricultural University, Guangzhou 510642, China
| | - Yan Wang
- College of Animal Science, National Engineering Research Center for Breeding Swine Industry, South China Agricultural University, Guangzhou 510642, China.
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38
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Taylor JA, Díez-Vives C, Nielsen S, Wemheuer B, Thomas T. Communality in microbial stress response and differential metabolic interactions revealed by time-series analysis of sponge symbionts. Environ Microbiol 2022; 24:2299-2314. [PMID: 35229422 DOI: 10.1111/1462-2920.15962] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2021] [Revised: 02/13/2022] [Accepted: 02/26/2022] [Indexed: 11/03/2022]
Abstract
The diversity and function of sponge-associated symbionts is now increasingly understood, however, we lack an understanding on how they dynamically behave to ensure holobiont stability in the face of environmental variation. Here we performed a metatransciptomics analysis of three microbial symbionts of the sponge Cymbastela concentrica in situ over 14 months and through differential gene expression and correlation analysis to environmental variables uncovered differences that speak to their metabolic activities and level of symbiotic and environmental interactions. The nitrite-oxidising Ca. Porinitrospira cymbastela maintained a seemingly stable metabolism, with the few differentially expressed genes related only to stress responses. The heterotrophic Ca. Porivivens multivorans displayed differential use of holobiont-derived compounds and respiration modes, while the ammonium-oxidising archaeon Ca. Nitrosopumilus cymbastelus differentially expressed genes related to phosphate metabolism and symbiosis effectors. One striking similarity between the symbionts was their similar variation in expression of stress-related genes. Our timeseries study showed that the microbial community of C. concentrica undertakes dynamic gene expression adjustments in response to the surroundings, tuned to deal with general stress and metabolic interactions between holobiont members. The success of these dynamic adjustments likely underpins the stability of the sponge holobiont and may provide resilience against environmental change. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Jessica A Taylor
- Centre for Marine Science and Innovation, University of New South Wales, Sydney, Australia.,School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, Australia
| | - Cristina Díez-Vives
- Centre for Marine Science and Innovation, University of New South Wales, Sydney, Australia.,Department of Biodiversity and Evolutionary Biology, Museo Nacional de Ciencias Naturales, Madrid, Spain
| | - Shaun Nielsen
- Centre for Marine Science and Innovation, University of New South Wales, Sydney, Australia
| | - Bernd Wemheuer
- Centre for Marine Science and Innovation, University of New South Wales, Sydney, Australia.,School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, Australia
| | - Torsten Thomas
- Centre for Marine Science and Innovation, University of New South Wales, Sydney, Australia.,School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, Australia
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Murphy ARJ, Scanlan DJ, Chen Y, Bending GD, Hammond JP, Wellington EMH, Lidbury IDEA. 2-aminoethylphosphonate utilisation in Pseudomonas putida BIRD-1 is controlled by multiple master regulators. Environ Microbiol 2022; 24:1902-1917. [PMID: 35229442 PMCID: PMC9311074 DOI: 10.1111/1462-2920.15959] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Accepted: 02/24/2022] [Indexed: 11/30/2022]
Abstract
Bacteria possess various regulatory mechanisms to detect and coordinate a response to elemental nutrient limitation. In pseudomonads, the two‐component system regulators CbrAB, NtrBC and PhoBR, are responsible for regulating cellular response to carbon (C), nitrogen (N) and phosphorus (P) respectively. Phosphonates are reduced organophosphorus compounds produced by a broad range of biota and typified by a direct C‐P bond. Numerous pseudomonads can use the environmentally abundant phosphonate species 2‐aminoethylphosphonate (2AEP) as a source of C, N, or P, but only PhoBR has been shown to play a role in 2AEP utilization. On the other hand, utilization of 2AEP as a C and N source is considered substrate inducible. Here, using the plant‐growth‐promoting rhizobacterium Pseudomonas putida BIRD‐1 we present evidence that 2AEP utilization is under dual regulation and only occurs upon depletion of C, N, or P, controlled by CbrAB, NtrBC, or PhoBR respectively. However, the presence of 2AEP was necessary for full gene expression, i.e. expression was substrate inducible. Mutation of a LysR‐type regulator, termed AepR, upstream of the 2AEP transaminase‐phosphonatase system (PhnWX), confirmed this dual regulatory mechanism. To our knowledge, this is the first study identifying coordination between global stress response and substrate‐specific regulators in phosphonate metabolism.
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Affiliation(s)
- Andrew R J Murphy
- School of Life Sciences, University of Warwick, Gibbet Hill Road, Coventry, UK
| | - David J Scanlan
- School of Life Sciences, University of Warwick, Gibbet Hill Road, Coventry, UK
| | - Yin Chen
- School of Life Sciences, University of Warwick, Gibbet Hill Road, Coventry, UK
| | - Gary D Bending
- School of Life Sciences, University of Warwick, Gibbet Hill Road, Coventry, UK
| | - John P Hammond
- School of Agriculture, Policy, and Development, University of Reading, Earley Gate, Whiteknights, Reading, UK
| | | | - Ian D E A Lidbury
- Plants, Photosynthesis and Soil Research Cluster, School of Biosciences, University of Sheffield, Sheffield, UK
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40
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Zhu Y, Wang J, Su W, Lu T, Li A, Pang X. Effects of dual deletion of glnR and mtrA on expression of nitrogen metabolism genes in Streptomyces venezuelae. Microb Biotechnol 2022; 15:1795-1810. [PMID: 35148463 PMCID: PMC9151340 DOI: 10.1111/1751-7915.14016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Revised: 01/28/2022] [Accepted: 01/30/2022] [Indexed: 11/30/2022] Open
Abstract
GlnR activates nitrogen metabolism genes under nitrogen‐limited conditions, whereas MtrA represses these genes under nutrient‐rich conditions in Streptomyces. In this study, we compared the transcription patterns of nitrogen metabolism genes in a double deletion mutant (ΔmtrA‐glnR) lacking both mtrA and glnR and in mutants lacking either mtrA (ΔmtrA) or glnR (ΔglnR). The nitrogen metabolism genes were expressed similarly in ΔmtrA‐glnR and ΔglnR under both nitrogen‐limited and nutrient‐rich conditions, with patterns distinctly different from that of ΔmtrA, suggesting a decisive role for GlnR in the control of nitrogen metabolism genes and further suggesting that regulation of these genes by MtrA is GlnR‐dependent. MtrA and GlnR utilize the same binding sites upstream of nitrogen metabolism genes, and we showed stronger in vivo binding of MtrA to these sites under nutrient‐rich conditions and of GlnR under nitrogen‐limited conditions, consistent with the higher levels of MtrA or GlnR under those respective conditions. In addition, we showed that both mtrA and glnR are self‐regulated. Our study provides new insights into the regulation of nitrogen metabolism genes in Streptomyces.
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Affiliation(s)
- Yanping Zhu
- The State Key Laboratory of Microbial Technology, Shandong University, Qingdao, 266237, China
| | - Jiao Wang
- The State Key Laboratory of Microbial Technology, Shandong University, Qingdao, 266237, China
| | - Wenya Su
- The State Key Laboratory of Microbial Technology, Shandong University, Qingdao, 266237, China
| | - Ting Lu
- The State Key Laboratory of Microbial Technology, Shandong University, Qingdao, 266237, China
| | - Aiying Li
- The State Key Laboratory of Microbial Technology, Shandong University, Qingdao, 266237, China
| | - Xiuhua Pang
- The State Key Laboratory of Microbial Technology, Shandong University, Qingdao, 266237, China
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41
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Hagberg KL, Price JP, Yurgel SN, Kahn ML. The Sinorhizobium meliloti Nitrogen Stress Response Changes Radically in the Face of Concurrent Phosphate Stress. Front Microbiol 2022; 13:800146. [PMID: 35154051 PMCID: PMC8829014 DOI: 10.3389/fmicb.2022.800146] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2021] [Accepted: 01/06/2022] [Indexed: 11/13/2022] Open
Abstract
Expression of hundreds of S. meliloti genes changed more than two-fold in response to either nitrogen or phosphate limitation. When these two stresses were applied together, stress responsive gene expression shifted dramatically. In particular, the nitrogen stress response in the presence of phosphate stress had only 30 of about 350 genes in common with the 280 genes that responded to nitrogen stress with adequate phosphate. Expression of sRNAs was also altered in response to these stresses. 82% of genes that responded to nitrogen stress also responded to phosphate stress, including 20 sRNAs. A subset of these sRNAs is known to be chaperoned by the RNA binding protein, Hfq. Hfq had previously been shown to influence about a third of the genes that responded to both nitrogen and phosphate stresses. Phosphate limitation influenced changes in gene expression more than nitrogen limitation and, when both stresses were present, phosphate stress sometimes reversed the direction of some of the changes induced by nitrogen stress. These nutrient stress responses are therefore context dependent.
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Affiliation(s)
- Kelly L. Hagberg
- School of Molecular Biosciences, Institute of Biological Chemistry, Washington State University, Pullman, WA, United States
| | - Jason P. Price
- School of Molecular Biosciences, Institute of Biological Chemistry, Washington State University, Pullman, WA, United States
| | - Svetlana N. Yurgel
- School of Molecular Biosciences, Institute of Biological Chemistry, Washington State University, Pullman, WA, United States
- Department of Plant, Food and Environmental Sciences, Dalhousie University, Truro, NS, Canada
| | - Michael L. Kahn
- School of Molecular Biosciences, Institute of Biological Chemistry, Washington State University, Pullman, WA, United States
- *Correspondence: Michael L. Kahn,
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42
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Bolay P, Hemm L, Florencio FJ, Hess WR, Muro-Pastor MI, Klähn S. The sRNA NsiR4 fine-tunes arginine synthesis in the cyanobacterium Synechocystis sp. PCC 6803 by post-transcriptional regulation of PirA. RNA Biol 2022; 19:811-818. [PMID: 35678613 PMCID: PMC9196836 DOI: 10.1080/15476286.2022.2082147] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022] Open
Abstract
As the only oxygenic phototrophs among prokaryotes, cyanobacteria employ intricate mechanisms to regulate common metabolic pathways. These mechanisms include small protein inhibitors exerting their function by protein-protein interaction with key metabolic enzymes and regulatory small RNAs (sRNAs). Here we show that the sRNA NsiR4, which is highly expressed under nitrogen limiting conditions, interacts with the mRNA of the recently described small protein PirA in the model strain Synechocystis sp. PCC 6803. In particular, NsiR4 targets the pirA 5'UTR close to the ribosome binding site. Heterologous reporter assays confirmed that this interaction interferes with pirA translation. PirA negatively impacts arginine synthesis under ammonium excess by competing with the central carbon/nitrogen regulator PII that binds to and thereby activates the key enzyme of arginine synthesis, N-acetyl-L-glutamate-kinase (NAGK). Consistently, ectopic nsiR4 expression in Synechocystis resulted in lowered PirA accumulation in response to ammonium upshifts, which also affected intracellular arginine pools. As NsiR4 and PirA are inversely regulated by the global nitrogen transcriptional regulator NtcA, this regulatory axis enables fine tuning of arginine synthesis and conveys additional metabolic flexibility under highly fluctuating nitrogen regimes. Pairs of small protein inhibitors and of sRNAs that control the abundance of these enzyme effectors at the post-transcriptional level appear as fundamental building blocks in the regulation of primary metabolism in cyanobacteria.
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Affiliation(s)
- Paul Bolay
- Department of Solar Materials, Helmholtz Centre for Environmental Research, Leipzig, Germany
| | - Luisa Hemm
- Genetics and Experimental Bioinformatics, Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Francisco J Florencio
- de Sevilla, Instituto de Bioquímica Vegetal Y FotosíntesisCSIC-Universidad, Sevilla, Spain
| | - Wolfgang R Hess
- Genetics and Experimental Bioinformatics, Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - M Isabel Muro-Pastor
- de Sevilla, Instituto de Bioquímica Vegetal Y FotosíntesisCSIC-Universidad, Sevilla, Spain
| | - Stephan Klähn
- Department of Solar Materials, Helmholtz Centre for Environmental Research, Leipzig, Germany
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43
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New views on PII signaling: from nitrogen sensing to global metabolic control. Trends Microbiol 2022; 30:722-735. [DOI: 10.1016/j.tim.2021.12.014] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2021] [Revised: 12/21/2021] [Accepted: 12/22/2021] [Indexed: 11/20/2022]
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Hu X, Zhang T, Ji K, Luo K, Wang L, Chen W. Transcriptome and metabolome analyses of response of Synechocystis sp. PCC 6803 to methyl viologen. Appl Microbiol Biotechnol 2021; 105:8377-8392. [PMID: 34668984 DOI: 10.1007/s00253-021-11628-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Revised: 09/21/2021] [Accepted: 09/28/2021] [Indexed: 10/20/2022]
Abstract
The toxicity of methyl viologen (MV) to organisms is mainly due to the oxidative stress caused by reactive oxygen species produced from cell response. This study mainly investigated the response of Synechocystis sp. PCC 6803 to MV by combining transcriptomic and metabolomic analyses. Through transcriptome sequencing, we found many genes responding to MV stress, and analyzed them by weighted gene co-expression network analysis (WGCNA). Meanwhile, many metabolites were also found by metabolomic analysis to be regulated post MV treatment. Based on the analysis results of Kyoto encyclopedia of genes and genomes (KEGG) of the differentially expressed genes (DEGs) in the transcriptome and the differential metabolites in the metabolome, the dynamic changes of genes and metabolites involved in ten metabolic pathways in response to MV were analyzed. The results indicated that although the oxidative stress caused by MV was the strongest at 6 h, the proportion of the upregulated genes and metabolites involved in these ten metabolic pathways was the highest. Photosynthesis positively regulated the response to MV-induced oxidative stress, and the regulation of environmental information processing was inhibited by MV. Other metabolic pathways played different roles at different times and interacted with each other to respond to MV. This study comprehensively analyzed the response of Synechocystis sp. PCC 6803 to oxidative stress caused by MV from a multi-omics perspective, with providing key data and important information for in-depth analysis of the response of organisms to MV, especially photosynthetic organisms. KEY POINTS: • Methyl viologen (MV) treatment caused regulatory changes in genes and metabolites. • Proportion of upregulated genes and metabolites was the highest at 6-h MV treatment. • Photosynthesis and environmental information processing involved in MV response.
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Affiliation(s)
- Xinyu Hu
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, 430070, Hubei, China
| | - Tianyuan Zhang
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, 430070, Hubei, China
| | - Kai Ji
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, 430070, Hubei, China
| | - Ke Luo
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, 430070, Hubei, China
| | - Li Wang
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, 430070, Hubei, China
| | - Wenli Chen
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, 430070, Hubei, China.
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45
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Gardner JG, Schreier HJ. Unifying themes and distinct features of carbon and nitrogen assimilation by polysaccharide-degrading bacteria: a summary of four model systems. Appl Microbiol Biotechnol 2021; 105:8109-8127. [PMID: 34611726 DOI: 10.1007/s00253-021-11614-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Revised: 09/20/2021] [Accepted: 09/21/2021] [Indexed: 11/24/2022]
Abstract
Our current understanding of enzymatic polysaccharide degradation has come from a huge number of in vitro studies with purified enzymes. While this vast body of work has been invaluable in identifying and characterizing novel mechanisms of action and engineering desirable traits into these enzymes, a comprehensive picture of how these enzymes work as part of a native in vivo system is less clear. Recently, several model bacteria have emerged with genetic systems that allow for a more nuanced study of carbohydrate active enzymes (CAZymes) and how their activity affects bacterial carbon metabolism. With these bacterial model systems, it is now possible to not only study a single nutrient system in isolation (i.e., carbohydrate degradation and carbon metabolism), but also how multiple systems are integrated. Given that most environmental polysaccharides are carbon rich but nitrogen poor (e.g., lignocellulose), the interplay between carbon and nitrogen metabolism in polysaccharide-degrading bacteria can now be studied in a physiologically relevant manner. Therefore, in this review, we have summarized what has been experimentally determined for CAZyme regulation, production, and export in relation to nitrogen metabolism for two Gram-positive (Caldicellulosiruptor bescii and Clostridium thermocellum) and two Gram-negative (Bacteroides thetaiotaomicron and Cellvibrio japonicus) polysaccharide-degrading bacteria. By comparing and contrasting these four bacteria, we have highlighted the shared and unique features of each, with a focus on in vivo studies, in regard to carbon and nitrogen assimilation. We conclude with what we believe are two important questions that can act as guideposts for future work to better understand the integration of carbon and nitrogen metabolism in polysaccharide-degrading bacteria. KEY POINTS: • Regardless of CAZyme deployment system, the generation of a local pool of oligosaccharides is a common strategy among Gram-negative and Gram-positive polysaccharide degraders as a means to maximally recoup the energy expenditure of CAZyme production and export. • Due to the nitrogen deficiency of insoluble polysaccharide-containing substrates, Gram-negative and Gram-positive polysaccharide degraders have a diverse set of strategies for supplementation and assimilation. • Future work needs to precisely characterize the energetic expenditures of CAZyme deployment and bolster our understanding of how carbon and nitrogen metabolism are integrated in both Gram-negative and Gram-positive polysaccharide-degrading bacteria, as both of these will significantly influence a given bacterium's suitability for biotechnology applications.
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Affiliation(s)
- Jeffrey G Gardner
- Department of Biological Sciences, University of Maryland, Baltimore County, Baltimore, MD, USA.
| | - Harold J Schreier
- Department of Biological Sciences, University of Maryland, Baltimore County, Baltimore, MD, USA.,Department of Marine Biotechnology, Institute of Marine and Environmental Technology, University of Maryland, Baltimore County, Baltimore, MD, USA
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Sakamoto T, Takatani N, Sonoike K, Jimbo H, Nishiyama Y, Omata T. Dissection of the Mechanisms of Growth Inhibition Resulting from Loss of the PII Protein in the Cyanobacterium Synechococcus elongatus PCC 7942. PLANT & CELL PHYSIOLOGY 2021; 62:721-731. [PMID: 33650637 PMCID: PMC8474142 DOI: 10.1093/pcp/pcab030] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/28/2020] [Accepted: 02/18/2021] [Indexed: 05/08/2023]
Abstract
In cyanobacteria, the PII protein (the glnB gene product) regulates a number of proteins involved in nitrogen assimilation including PipX, the coactivator of the global nitrogen regulator protein NtcA. In Synechococcus elongatus PCC 7942, construction of a PII-less mutant retaining the wild-type pipX gene is difficult because of the toxicity of uncontrolled action of PipX and the other defect(s) resulting from the loss of PIIper se, but the nature of the PipX toxicity and the PipX-independent defect(s) remains unclear. Characterization of a PipX-less glnB mutant (PD4) in this study showed that the loss of PII increases the sensitivity of PSII to ammonium. Ammonium was shown to stimulate the formation of reactive oxygen species in the mutant cells. The ammonium-sensitive growth phenotype of PD4 was rescued by the addition of an antioxidant α-tocopherol, confirming that photo-oxidative damage was the major cause of the growth defect. A targeted PII mutant retaining wild-type pipX was successfully constructed from the wild-type S. elongatus strain (SPc) in the presence of α-tocopherol. The resulting mutant (PD1X) showed an unusual chlorophyll fluorescence profile, indicating extremely slow reduction and re-oxidation of QA, which was not observed in mutants defective in both glnB and pipX. These results showed that the aberrant action of uncontrolled PipX resulted in an impairment of the electron transport reactions in both the reducing and oxidizing sides of QA.
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Affiliation(s)
- Takayuki Sakamoto
- Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, 464-8601 Japan
| | - Nobuyuki Takatani
- Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, 464-8601 Japan
| | - Kintake Sonoike
- Faculty of Education and Integrated Arts and Sciences, Waseda University, Tokyo, 162-8480 Japan
| | - Haruhiko Jimbo
- Graduate School of Science and Engineering, Saitama University, Saitama, 338-8570 Japan
- Graduate School of Arts and Sciences, University of Tokyo,Tokyo 153-8902Japan
| | - Yoshitaka Nishiyama
- Graduate School of Science and Engineering, Saitama University, Saitama, 338-8570 Japan
| | - Tatsuo Omata
- * Corresponding author: E-mail, ; Fax, +81-52-789-4107
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47
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The Classical, Yet Controversial, First Enzyme of Lipid Synthesis: Escherichia coli Acetyl-CoA Carboxylase. Microbiol Mol Biol Rev 2021; 85:e0003221. [PMID: 34132100 DOI: 10.1128/mmbr.00032-21] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Escherichia coli acetyl-CoA carboxylase (ACC), the enzyme responsible for synthesis of malonyl-CoA, the building block of fatty acid synthesis, is the paradigm bacterial ACC. Many reports on the structures and stoichiometry of the four subunits comprising the active enzyme as well as on regulation of ACC activity and expression have appeared in the almost 20 years since this subject was last reviewed. This review seeks to update and expand on these reports.
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48
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The Oxoglutarate Binding Site and Regulatory Mechanism Are Conserved in Ammonium Transporter Inhibitors GlnKs from Methanococcales. Int J Mol Sci 2021; 22:ijms22168631. [PMID: 34445335 PMCID: PMC8395244 DOI: 10.3390/ijms22168631] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Revised: 08/04/2021] [Accepted: 08/05/2021] [Indexed: 11/16/2022] Open
Abstract
Protein inhibition is a natural regulatory process to control cellular metabolic fluxes. PII-family signal-transducing effectors are in this matter key regulators of the nitrogen metabolism. Their interaction with their various targets is governed by the cellular nitrogen level and the energy charge. Structural studies on GlnK, a PII-family inhibitor of the ammonium transporters (Amt), showed that the T-loops responsible for channel obstruction are displaced upon the binding of 2-oxoglutarate, magnesium and ATP in a conserved cleft. However, GlnK from Methanocaldococcus jannaschii was shown to bind 2-oxoglutarate on the tip of its T-loop, causing a moderate disruption to GlnK-Amt interaction, raising the question if methanogenic archaea use a singular adaptive strategy. Here we show that membrane fractions of Methanothermococcus thermolithotrophicus released GlnKs only in the presence of Mg-ATP and 2-oxoglutarate. This observation led us to structurally characterize the two GlnK isoforms apo or in complex with ligands. Together, our results show that the 2-oxoglutarate binding interface is conserved in GlnKs from Methanococcales, including Methanocaldococcus jannaschii, emphasizing the importance of a free carboxy-terminal group to facilitate ligand binding and to provoke the shift of the T-loop positions.
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49
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Kang S, Park H, Lee KJ, Lee KH. Transcription activation of two clusters for exopolysaccharide biosynthesis by phosphorylated DctD in Vibrio vulnificus. Environ Microbiol 2021; 23:5364-5377. [PMID: 34110060 DOI: 10.1111/1462-2920.15636] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 05/28/2021] [Accepted: 06/08/2021] [Indexed: 11/28/2022]
Abstract
NtrC-mediated production of exopolysaccharides (EPS), essential components for Vibrio vulnificus biofilms, is highly increased in the presence of dicarboxylic or tricarboxylic acids. Gel-shift assays showed that regulation of the EPS-gene cluster I (EPS-I cluster) by NtrC was direct via binding of phosphorylated NtrC (p-NtrC) to the regulatory region of the EPS-I cluster. In contrast, p-NtrC did not bind to the EPS-II and EPS-III clusters, suggesting that NtrC regulation was not direct and another transcription factor belonging to an NtrC-regulon might play a role in activating their transcription. A candidate transcription factor, DctD, of which expression was induced by NtrC, activated the expression of the EPS-II and EPS-III clusters via direct binding to their upstream regions. Under growth conditions with either dicarboxylic or tricarboxylic acids, the expression of NtrC was induced and the transcription of dctD was activated. Furthermore, DctD exhibited higher transcriptional activity under the conditions with dicarboxylic acids than with tricarboxylic acids. Therefore, this study demonstrates that under dicarboxylate-rich conditions, both the abundance and activity of DctD were markedly induced, which activates the expression of two EPS clusters to maximize biosynthesis of EPS facilitating biofilm maturation in V. vulnificus.
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Affiliation(s)
- Sebin Kang
- Department of Life Science, Sogang University, Seoul, South Korea
| | - Hana Park
- Department of Life Science, Sogang University, Seoul, South Korea
| | - Kyung-Jo Lee
- Department of Life Science, Sogang University, Seoul, South Korea
| | - Kyu-Ho Lee
- Department of Life Science, Sogang University, Seoul, South Korea
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50
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Ghenov F, Gerhardt ECM, Huergo LF, Pedrosa FO, Wassem R, Souza EM. Characterization of glutamine synthetase from the ammonium-excreting strain HM053 of Azospirillum brasilense. BRAZ J BIOL 2021; 82:e235927. [PMID: 34076164 DOI: 10.1590/1519-6984.235927] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Accepted: 07/29/2020] [Indexed: 11/21/2022] Open
Abstract
Glutamine synthetase (GS), encoded by glnA, catalyzes the conversion of L-glutamate and ammonium to L-glutamine. This ATP hydrolysis driven process is the main nitrogen assimilation pathway in the nitrogen-fixing bacterium Azospirillum brasilense. The A. brasilense strain HM053 has poor GS activity and leaks ammonium into the medium under nitrogen fixing conditions. In this work, the glnA genes of the wild type and HM053 strains were cloned into pET28a, sequenced and overexpressed in E. coli. The GS enzyme was purified by affinity chromatography and characterized. The GS of HM053 strain carries a P347L substitution, which results in low enzyme activity and rendered the enzyme insensitive to adenylylation by the adenilyltransferase GlnE.
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Affiliation(s)
- Fernanda Ghenov
- Universidade Federal do Paraná - UFPR, Departamento de Bioquímica e Biologia Molecular, Núcleo de Fixação Biológica de Nitrogênio, Curitiba, PR, Brasil
| | - Edileusa Cristina Marques Gerhardt
- Universidade Federal do Paraná - UFPR, Departamento de Bioquímica e Biologia Molecular, Núcleo de Fixação Biológica de Nitrogênio, Curitiba, PR, Brasil
| | | | - Fabio Oliveira Pedrosa
- Universidade Federal do Paraná - UFPR, Departamento de Bioquímica e Biologia Molecular, Núcleo de Fixação Biológica de Nitrogênio, Curitiba, PR, Brasil
| | - Roseli Wassem
- Universidade Federal do Paraná - UFPR, Departamento de Genética, Curitiba, PR, Brasil
| | - Emanuel Maltempi Souza
- Universidade Federal do Paraná - UFPR, Departamento de Bioquímica e Biologia Molecular, Núcleo de Fixação Biológica de Nitrogênio, Curitiba, PR, Brasil
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