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Nagraj AK, Shukla M, Kulkarni M, Patil P, Borgave M, Banerjee SK. Reversal of carbapenem resistance in Pseudomonas aeruginosa by camelid single domain antibody fragment (VHH) against the C4-dicarboxylate transporter. J Antibiot (Tokyo) 2024:10.1038/s41429-024-00748-w. [PMID: 38886486 DOI: 10.1038/s41429-024-00748-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2023] [Revised: 05/06/2024] [Accepted: 05/18/2024] [Indexed: 06/20/2024]
Abstract
Antimicrobial resistance is emerging as the new healthcare crisis necessitating the development of newer classes of drugs using non-traditional approaches. Pseudomonas aeruginosa, one of the most common pathogens involved in nosocomial infections, is extremely difficult to treat even with the last resort frontline drug, the carbapenems. As the pathogen has the ability to acquire resistance to new small-molecule antibiotics, being deployed, a novel biological approach has been tried using antibody fragments in combination with carbapenems and β-lactams as adjunct therapy for an enduring solution to the problem. In this study, we developed a camelid antibody fragment (VHH) library against P. aeruginosa and isolated a highly potent hit, PsC23. Mass spectrometry identified the target to be a component of the C4-dicarboxylate transporter that feeds metabolites to the glyoxylate shunt particularly under conditions of oxidative stress. PsC23 is bacteriostatic at a concentration of 1.66 µM (25 µg ml-1) and shows a synergistic effect with both the classes of drugs at an effective concentration of 100-200 nM (1.5-3.0 µg ml-1) when co administered with them. In combination with meropenem the VHH completely cleared the infection from a neutropenic mouse with a carbapenem-resistant P. aeruginosa systemic infection. Blocking the glyoxylate shunt by PsC23 resulted in disruption of energy transduction due to a respiratory shift to the oxygen-depleted TCA cycle causing inhibition of efflux and increased free radical generation from carbapenems and β-lactams exerting a strong bactericidal effect that reversed the resistance to multiple unrelated drugs.
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Affiliation(s)
| | | | | | - Pratik Patil
- AbGenics Life Sciences Pvt. Ltd, Pune, 411045, India
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2
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Schroven K, Putzeys L, Kerremans A, Ceyssens PJ, Vallino M, Paeshuyse J, Haque F, Yusuf A, Koch MD, Lavigne R. The phage-encoded PIT4 protein affects multiple two-component systems of Pseudomonas aeruginosa. Microbiol Spectr 2023; 11:e0237223. [PMID: 37962408 PMCID: PMC10714779 DOI: 10.1128/spectrum.02372-23] [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: 06/08/2023] [Accepted: 10/04/2023] [Indexed: 11/15/2023] Open
Abstract
IMPORTANCE More and more Pseudomonas aeruginosa isolates have become resistant to antibiotics like carbapenem. As a consequence, P. aeruginosa ranks in the top three of pathogens for which the development of novel antibiotics is the most crucial. The pathogen causes both acute and chronic infections, especially in patients who are the most vulnerable. Therefore, efforts are urgently needed to develop alternative therapies. One path explored in this article is the use of bacteriophages and, more specifically, phage-derived proteins. In this study, a phage-derived protein was studied that impacts key virulence factors of the pathogen via interaction with multiple histidine kinases of TCSs. The fundamental insights gained for this protein can therefore serve as inspiration for the development of an anti-virulence compound that targets the bacterial TCS.
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Affiliation(s)
- Kaat Schroven
- Laboratory of Gene Technology, KU Leuven, Leuven, Belgium
| | - Leena Putzeys
- Laboratory of Gene Technology, KU Leuven, Leuven, Belgium
| | | | | | - Marta Vallino
- Institute of Sustainable Plant Protection, National Research Council of Italy, Turin, Italy
| | - Jan Paeshuyse
- Host and Pathogen Interactions, KU Leuven, Leuven, Belgium
| | - Farhana Haque
- Department of Biology, Texas A&M University, College Station, Texas, USA
| | - Ahmed Yusuf
- Department of Biology, Texas A&M University, College Station, Texas, USA
| | - Matthias D. Koch
- Department of Biology, Texas A&M University, College Station, Texas, USA
| | - Rob Lavigne
- Laboratory of Gene Technology, KU Leuven, Leuven, Belgium
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3
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Zhang Z, Liu Y, Zhao W, Ji M. Radiation impacts gene redundancy and biofilm regulation of cryoconite microbiomes in Northern Hemisphere glaciers. MICROBIOME 2023; 11:228. [PMID: 37848997 PMCID: PMC10583317 DOI: 10.1186/s40168-023-01621-y] [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: 04/06/2023] [Accepted: 07/14/2023] [Indexed: 10/19/2023]
Abstract
BACKGROUND Glaciers harbor diverse microorganisms adapted to extreme conditions with high radiation, fluctuating temperature, and low nutrient availability. In glacial ecosystems, cryoconite granules are hotspots of microbial metabolic activity and could influences the biogeochemical cycle on glacier surface. Climate change could influence glacier dynamics by changing regional meteorological factors (e.g., radiation, precipitation, temperature, wind, and evaporation). Moreover, meteorological factors not only influence glacier dynamics but also directly or indirectly influence cryoconite microbiomes. However, the relationship of the meteorological factors and cryoconite microbiome are poorly understood. RESULTS Here, we collected 88 metagenomes from 26 glaciers distributed in the Northern Hemisphere with corresponding public meteorological data to reveal the relationship between meteorological factors and variation of cryoconite microbiome. Our results showed significant differences in taxonomic and genomic characteristics between cryoconite generalists and specialists. Additionally, we found that the biogeography of both generalists and specialists was influenced by solar radiation. Specialists with smaller genome size and lower gene redundancy were more abundant under high radiation stress, implying that streamlined genomes are more adapted to high radiation conditions. Network analysis revealed that biofilm regulation is a ubiquitous function in response to radiation stress, and hub genes were associated with the formation and dispersion of biofilms. CONCLUSION These findings enhance our understanding of glacier cryoconite microbiome variation on a hemispheric scale and indicate the response mechanisms to radiation stress, which will support forecasts of the ecological consequences of future climate change. Video Abstract.
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Affiliation(s)
- Zhihao Zhang
- State Key Laboratory of Tibetan Plateau Earth System, Resources and Environment (TPESRE), Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing, 100101, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Yongqin Liu
- State Key Laboratory of Tibetan Plateau Earth System, Resources and Environment (TPESRE), Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing, 100101, China.
- University of Chinese Academy of Sciences, Beijing, 100049, China.
- Center for Pan-Third Pole Environment, Lanzhou University, Lanzhou, 730000, China.
| | - Weishu Zhao
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China
- SJTU Yazhou Bay Institute of Deepsea Sci-Tech, Yongyou Industrial Park, Sanya, 572024, China
- International Center for Deep Life Investigation (IC-DLI), Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Mukan Ji
- Center for Pan-Third Pole Environment, Lanzhou University, Lanzhou, 730000, China
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4
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Madigan MT, Bender KS, Sanguedolce SA, Parenteau MN, Mayer MH, Kimura Y, Wang-Otomo ZY, Sattley WM. Genomic basis for the unique phenotype of the alkaliphilic purple nonsulfur bacterium Rhodobaca bogoriensis. Extremophiles 2023; 27:19. [PMID: 37481751 DOI: 10.1007/s00792-023-01304-4] [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: 04/07/2023] [Accepted: 07/14/2023] [Indexed: 07/25/2023]
Abstract
Although several species of purple sulfur bacteria inhabit soda lakes, Rhodobaca bogoriensis is the first purple nonsulfur bacterium cultured from such highly alkaline environments. Rhodobaca bogoriensis strain LBB1T was isolated from Lake Bogoria, a soda lake in the African Rift Valley. The phenotype of Rhodobaca bogoriensis is unique among purple bacteria; the organism is alkaliphilic but not halophilic, produces carotenoids absent from other purple nonsulfur bacteria, and is unable to grow autotrophically or fix molecular nitrogen. Here we analyze the draft genome sequence of Rhodobaca bogoriensis to gain further insight into the biology of this extremophilic purple bacterium. The strain LBB1T genome consists of 3.91 Mbp with no plasmids. The genome sequence supports the defining characteristics of strain LBB1T, including its (1) production of a light-harvesting 1-reaction center (LH1-RC) complex but lack of a peripheral (LH2) complex, (2) ability to synthesize unusual carotenoids, (3) capacity for both phototrophic (anoxic/light) and chemotrophic (oxic/dark) energy metabolisms, (4) utilization of a wide variety of organic compounds (including acetate in the absence of a glyoxylate cycle), (5) ability to oxidize both sulfide and thiosulfate despite lacking the capacity for autotrophic growth, and (6) absence of a functional nitrogen-fixation system for diazotrophic growth. The assortment of properties in Rhodobaca bogoriensis has no precedent among phototrophic purple bacteria, and the results are discussed in relation to the organism's soda lake habitat and evolutionary history.
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Affiliation(s)
- Michael T Madigan
- School of Biological Sciences, Southern Illinois University, Carbondale, IL, 62901, USA
| | - Kelly S Bender
- School of Biological Sciences, Southern Illinois University, Carbondale, IL, 62901, USA
| | - Sophia A Sanguedolce
- School of Biological Sciences, Southern Illinois University, Carbondale, IL, 62901, USA
| | - Mary N Parenteau
- Exobiology Branch, NASA Ames Research Center, Moffett Field, CA, 94035, USA
| | - Marisa H Mayer
- Exobiology Branch, NASA Ames Research Center, Moffett Field, CA, 94035, USA
| | - Yukihiro Kimura
- Department of Agrobioscience, Kobe University, Kobe, 657-8501, Japan
| | | | - W Matthew Sattley
- Division of Natural Sciences, Indiana Wesleyan University, Marion, IN, 46953, USA.
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5
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Dissecting key residues of a C4-dicarboxylic acid transporter to accelerate malate export in Myceliophthora. Appl Microbiol Biotechnol 2023; 107:609-622. [PMID: 36542100 DOI: 10.1007/s00253-022-12336-9] [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: 10/17/2022] [Revised: 12/05/2022] [Accepted: 12/08/2022] [Indexed: 12/24/2022]
Abstract
Efficient transporters are necessary for high concentration and purity of desired products during industrial production. In this study, we explored the mechanism of substrate transport and preference of the C4-dicarboxylic acid transporter AoMAE in the fungus Myceliophthora thermophila, and investigated the roles of 18 critical amino acid residues within this process. Among them, the residue Arg78, forming a hydrogen bond network with Arg23, Phe25, Thr74, Leu81, His82, and Glu94 to stabilize the protein conformation, is irreplaceable for the export function of AoMAE. Furthermore, varying the residue at position 100 resulted in changes to the size and shape of the substrate binding pocket, leading to alterations in transport efficiencies of both malic acid and succinic acid. We found that the mutation T100S increased malate production by 68%. Using these insights, we successfully generated an AoMAE variant with mutation T100S and deubiquitination, exhibiting an 81% increase in the selective export activity of malic acid. Simply introducing this version of AoMAE into M. thermophila wild-type strain increased production of malic acid from 1.22 to 54.88 g/L. These findings increase our understanding of the structure-function relationships of organic acid transporters and may accelerate the process of engineering dicarboxylic acid transporters with high efficiency. KEY POINTS: • This is the first systematical analysis of key residues of a malate transporter in fungi. • Protein engineering of AoMAE led to 81% increase of malate export activity. • Arg78 was essential for the normal function of AoMAE in M. thermophila. • Substitution of Thr100 affected export efficiency and substrate selectivity of AoMAE.
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Chen H, Wu X, Sun R, Lu H, Lin R, Gao X, Li G, Feng Z, Zhu R, Yao Y, Feng B, Liu Z. Dysregulation of CD177 + neutrophils on intraepithelial lymphocytes exacerbates gut inflammation via decreasing microbiota-derived DMF. Gut Microbes 2023; 15:2172668. [PMID: 36729914 PMCID: PMC9897772 DOI: 10.1080/19490976.2023.2172668] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Neutrophils synergize with intestinal resident intraepithelial lymphocytes (IELs) to serve as the first-line defense and maintain intestinal homeostasis. However, the underlying mechanisms whereby neutrophils regulate IELs to inhibit intestinal inflammation are still not completely understood. Here, we found that depletion of neutrophils (especially CD177+ subset) caused expansion of colitogenic TCRγδ+CD8αα+ IELs, increased intestinal inflammation, and dysbiosis after dextran sulfate sodium exposure or Citrobacter rodentium infection in mice. scRNA-seq analysis revealed a pyroptosis-related gene signature and hyperresponsiveness to microbiota in TCRγδ+CD8αα+ IELs from colitic Cd177-/- mice. Microbiota-derived fumarate and its derivative dimethyl fumarate (DMF), as well as fumarate-producing microbiotas, decreased in the feces of colitic Cd177-/- mice. Elimination of dysbiosis by antibiotics treatment or co-housing procedure and DMF supplementation restrained TCRγδ+CD8αα+ IEL activation. Consistently, DMF significantly alleviated intestinal mucosal inflammation in mice through restricting gasdermin D (GSDMD)-induced pyroptosis of TCRγδ+CD8αα+ IELs. Therefore, our data reveal that neutrophils inhibit intestinal inflammation by promoting microbiota-derived DMF to regulate TCRγδ+CD8αα+ IEL activation in a GSDMD-mediated pyroptosis-dependent manner, and that DMF may serve as a therapeutic target for the management of intestinal inflammation.
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Affiliation(s)
- Huimin Chen
- Center for Inflammatory Bowel Disease Research, The Shanghai Tenth People’s Hospital, Tongji University School of Medicine, Shanghai, China
| | - Xiaohan Wu
- Center for Inflammatory Bowel Disease Research, The Shanghai Tenth People’s Hospital, Tongji University School of Medicine, Shanghai, China
| | - Ruicong Sun
- Center for Inflammatory Bowel Disease Research, The Shanghai Tenth People’s Hospital, Tongji University School of Medicine, Shanghai, China
| | - Huiying Lu
- Center for Inflammatory Bowel Disease Research, The Shanghai Tenth People’s Hospital, Tongji University School of Medicine, Shanghai, China
| | - Ritian Lin
- Center for Inflammatory Bowel Disease Research, The Shanghai Tenth People’s Hospital, Tongji University School of Medicine, Shanghai, China
| | - Xiang Gao
- Center for Inflammatory Bowel Disease Research, The Shanghai Tenth People’s Hospital, Tongji University School of Medicine, Shanghai, China
| | - Gengfeng Li
- Center for Inflammatory Bowel Disease Research, The Shanghai Tenth People’s Hospital, Tongji University School of Medicine, Shanghai, China
| | - Zhongsheng Feng
- Center for Inflammatory Bowel Disease Research, The Shanghai Tenth People’s Hospital, Tongji University School of Medicine, Shanghai, China
| | - Ruixin Zhu
- Department of Bioinformatics, School of Life Sciences and Technology, Tongji University, Shanghai, China
| | - Yao Yao
- Department of Gastroenterology, The Second Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Baisui Feng
- Department of Gastroenterology, The Second Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Zhanju Liu
- Center for Inflammatory Bowel Disease Research, The Shanghai Tenth People’s Hospital, Tongji University School of Medicine, Shanghai, China,Department of Gastroenterology, The Second Affiliated Hospital of Zhengzhou University, Zhengzhou, China,Division of Immunology, School of Basic Medical Sciences, Henan University of Science and Technology, Luoyang, China,CONTACT Zhanju Liu Center for IBD Research, The Shanghai Tenth People’s Hospital of Tongji University, Shanghai, China
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7
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Systems-Wide Dissection of Organic Acid Assimilation in Pseudomonas aeruginosa Reveals a Novel Path To Underground Metabolism. mBio 2022; 13:e0254122. [PMID: 36377867 PMCID: PMC9765439 DOI: 10.1128/mbio.02541-22] [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] [Indexed: 11/16/2022] Open
Abstract
The human pathogen Pseudomonas aeruginosa (Pa) is one of the most frequent and severe causes of nosocomial infection. This organism is also a major cause of airway infections in people with cystic fibrosis (CF). Pa is known to have a remarkable metabolic plasticity, allowing it to thrive under diverse environmental conditions and ecological niches; yet, little is known about the central metabolic pathways that sustain its growth during infection or precisely how these pathways operate. In this work, we used a combination of 'omics approaches (transcriptomics, proteomics, metabolomics, and 13C-fluxomics) and reverse genetics to provide systems-level insight into how the infection-relevant organic acids succinate and propionate are metabolized by Pa. Moreover, through structural and kinetic analysis of the 2-methylcitrate synthase (2-MCS; PrpC) and its paralogue citrate (CIT) synthase (GltA), we show how these two crucial enzymatic steps are interconnected in Pa organic acid assimilation. We found that Pa can rapidly adapt to the loss of GltA function by acquiring mutations in a transcriptional repressor, which then derepresses prpC expression. Our findings provide a clear example of how "underground metabolism," facilitated by enzyme substrate promiscuity, "rewires" Pa metabolism, allowing it to overcome the loss of a crucial enzyme. This pathogen-specific knowledge is critical for the advancement of a model-driven framework to target bacterial central metabolism. IMPORTANCE Pseudomonas aeruginosa is an opportunistic human pathogen that, due to its unrivalled resistance to antibiotics, ubiquity in the built environment, and aggressiveness in infection scenarios, has acquired the somewhat dubious accolade of being designated a "critical priority pathogen" by the WHO. In this work, we uncover the pathways and mechanisms used by P. aeruginosa to grow on a substrate that is abundant at many infection sites: propionate. We found that if the organism is prevented from metabolizing propionate, the substrate turns from being a convenient nutrient source into a potent poison, preventing bacterial growth. We further show that one of the enzymes involved in these reactions, 2-methylcitrate synthase (PrpC), is promiscuous and can moonlight for another essential enzyme in the cell (citrate synthase). Indeed, mutations that abolish citrate synthase activity (which would normally prevent the cell from growing) can be readily overcome if the cell acquires additional mutations that increase the expression of PrpC. This is a nice example of the evolutionary utility of so-called "underground metabolism."
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Ke N, Kumka JE, Fang M, Weaver B, Burstyn JN, Bauer CE. RedB, a Member of the CRP/FNR Family, Functions as a Transcriptional Redox Brake. Microbiol Spectr 2022; 10:e0235322. [PMID: 36106751 PMCID: PMC9603854 DOI: 10.1128/spectrum.02353-22] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Accepted: 08/25/2022] [Indexed: 01/04/2023] Open
Abstract
Phylogenetic and sequence similarity network analyses of the CRP (cyclic AMP receptor protein)/FNR (fumarate and nitrate reductase regulatory protein) family of transcription factors indicate the presence of numerous subgroups, many of which have not been analyzed. Five homologs of the CRP/FNR family are present in the Rhodobacter capsulatus genome. One is a member of a broadly disseminated, previously uncharacterized CRP/FNR family subgroup encoded by the gene rcc01561. In this study, we utilize mutational disruption, transcriptome sequencing (RNA-seq), and chromatin immunoprecipitation sequencing (ChIP-seq) to determine the role of RCC01561 in regulating R. capsulatus physiology. This analysis shows that a mutant strain disrupted for rcc01561 exhibits altered expression of 451 genes anaerobically. A detailed analysis of the affected loci shows that RCC01561 represses photosynthesis and favors catabolism over anabolism and the use of the Entner-Doudoroff shunt and glycolysis over that of the tricarboxylic acid (TCA) cycle to limit NADH and ATP formation. This newly characterized CRP/FNR family member with a predominant role in reducing the production of reducing potential and ATP is given the nomenclature RedB as it functions as an energy and redox brake. Beyond limiting energy production, RedB also represses the expression of numerous genes involved in protein synthesis, including those involved in translation initiation, tRNA synthesis and charging, and amino acid biosynthesis. IMPORTANCE CRP and FNR are well-characterized members of the CRP/FNR family of regulatory proteins that function to maximize cellular energy production. In this study, we identify several new subgroups of the CRP/FNR family, many of which have not yet been characterized. Using Rhodobacter capsulatus as a model, we have mutationally disrupted the gene rcc01561, which codes for a transcription factor that is a member of a unique subgroup of the CRP/FNR family. Transcriptomic analysis shows that the disruption of rcc01561 leads to the altered expression of 451 genes anaerobically. Analysis of these regulated genes indicates that RCC01561 has a novel role in limiting cellular energy production. To our knowledge, this is first example of a member of the CRP/FNR family that functions as a brake on cellular energy production.
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Affiliation(s)
- Nijia Ke
- Molecular and Cellular Biochemistry Department, Indiana University, Bloomington, Indiana, USA
| | - Joseph E. Kumka
- Molecular and Cellular Biochemistry Department, Indiana University, Bloomington, Indiana, USA
| | - Mingxu Fang
- Molecular and Cellular Biochemistry Department, Indiana University, Bloomington, Indiana, USA
| | - Brian Weaver
- Department of Chemistry, University of Wisconsin—Madison, Madison, Wisconsin, USA
| | - Judith N. Burstyn
- Department of Chemistry, University of Wisconsin—Madison, Madison, Wisconsin, USA
| | - Carl E. Bauer
- Molecular and Cellular Biochemistry Department, Indiana University, Bloomington, Indiana, USA
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9
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Ke N, Kumka JE, Fang M, Weaver B, Burstyn JN, Bauer CE. Redox Brake Regulator RedB and FnrL Function as Yin-Yang Regulators of Anaerobic-Aerobic Metabolism in Rhodobacter capsulatus. Microbiol Spectr 2022; 10:e0235422. [PMID: 36106752 PMCID: PMC9603517 DOI: 10.1128/spectrum.02354-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Accepted: 08/25/2022] [Indexed: 01/04/2023] Open
Abstract
We recently described a new member of the CRP (cyclic AMP receptor protein)/FNR (fumarate and nitrate reductase regulatory protein) family called RedB, an acronym for redox brake, that functions to limit the production of ATP and NADH. This study shows that the RedB regulon significantly overlaps the FnrL regulon, with 199 genes being either directly or indirectly regulated by both of these global regulatory proteins. Among these 199 coregulated genes, 192 are divergently regulated, indicating that RedB functions as an antagonist of FnrL. Chromatin immunoprecipitation sequencing (ChIP-seq) analysis indicates that RedB and Fnr directly coregulate only 4 out of 199 genes. The primary mechanism for the divergent regulation of target genes thus involves indirect regulation by both RedB and FnrL (156 cases). Additional regulation involves direct binding by RedB and indirect regulation by FnrL (36 cases) or direct binding by FnrL and indirect regulation by RedB (3 cases). Analysis of physiological pathways under direct and indirect control by these global regulators demonstrates that RedB functions primarily to limit energy production, while FnrL functions to enhance energy production. This regulation includes glycolysis, gluconeogenesis, photosynthesis, hydrogen oxidation, electron transport, carbon fixation, lipid biosynthesis, and protein synthesis. Finally, we show that 75% of genomes from diverse species that code for RedB proteins also harbor genes coding for FNR homologs. This cooccurrence indicates that RedB likely has an important role in buffering FNR-mediated energy production in a broad range of species. IMPORTANCE The CRP/FNR family of regulatory proteins constitutes a large collection of related transcription factors, several of which globally regulate cellular energy production. A well-characterized example is FNR (called FnrL in Rhodobacter capsulatus), which is responsible for regulating the expression of numerous genes that promote maximal energy production and growth under anaerobic conditions. In a companion article (N. Ke, J. E. Kumka, M. Fang, B. Weaver, et al., Microbiol Spectr 10:e02353-22, 2022, https://doi.org/10.1128/Spectrum02353-22), we identified a new subgroup of the CRP/FNR family and demonstrated that a member of this new subgroup, called RedB, has a role in limiting cellular energy production. In this study, we show that numerous genes encompassing the RedB regulon significantly overlap genes that are members of the FnrL regulon. Furthermore, 97% of the genes that are members of both the RedB and FnrL regulons are divergently regulated by these two transcription factors. RedB thus functions as a buffer limiting the amount of energy production that is promoted by FnrL.
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Affiliation(s)
- Nijia Ke
- Molecular and Cellular Biochemistry Department, Indiana University, Bloomington, Indiana, USA
| | - Joseph E. Kumka
- Molecular and Cellular Biochemistry Department, Indiana University, Bloomington, Indiana, USA
| | - Mingxu Fang
- Molecular and Cellular Biochemistry Department, Indiana University, Bloomington, Indiana, USA
| | - Brian Weaver
- Department of Chemistry, University of Wisconsin—Madison, Madison, Wisconsin, USA
| | - Judith N. Burstyn
- Department of Chemistry, University of Wisconsin—Madison, Madison, Wisconsin, USA
| | - Carl E. Bauer
- Molecular and Cellular Biochemistry Department, Indiana University, Bloomington, Indiana, USA
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Xiong W, Perna A, Jacob IB, Lundgren BR, Wang G. The Enhancer-Binding Protein MifR, an Essential Regulator of α-Ketoglutarate Transport, Is Required for Full Virulence of Pseudomonas aeruginosa PAO1 in a Mouse Model of Pneumonia. Infect Immun 2022; 90:e0013622. [PMID: 36125307 PMCID: PMC9584295 DOI: 10.1128/iai.00136-22] [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] [Indexed: 11/20/2022] Open
Abstract
The opportunistic human pathogen Pseudomonas aeruginosa PAO1 has an extensive metabolism, enabling it to utilize a wide range of structurally diverse compounds to meet its nutritional and energy needs. Interestingly, the utilization of some of the more unusual compounds often associated with a eukaryotic-host environment is regulated via enhancer-binding proteins (EBPs) in P. aeruginosa. Whether the utilization of such compounds and the EBPs involved contribute to the pathogenesis of P. aeruginosa remains to be fully understood. To narrow this gap, we investigated the roles of the EBPs EatR (regulator of ethanolamine catabolism), DdaR (regulator of methylarginine catabolism), and MifR (regulator of α-ketoglutarate or α-KG transport) in the virulence of P. aeruginosa PAO1 in a pneumonia-induced septic mouse model. Deletion of genes encoding EatR and DdaR had no significant effect on the mortality of P. aeruginosa PAO1-infected mice compared to wide-type (WT) PAO1-infected mice. In contrast, infected mice with ΔmifR mutant exhibited a significant reduction (~50%) in the mortality rate compared with WT PAO1 (P < 0.05). Infected mice with ΔmifR PAO1 had lower lung injury scores, fewer inflammatory cells, decreased proinflammatory cytokines, and decreased apoptosis and cell death compared to mice infected with WT PAO1 (P < 0.05). Furthermore, molecular analysis revealed decreased NLRP3 inflammasome activation in infected mice with ΔmifR PAO1 compared to WT PAO1 (P < 0.05). These results suggested that the utilization of α-KG was a contributing factor in P. aeruginosa-mediated pneumonia and sepsis and that MifR-associated regulation may be a potential therapeutic target for P. aeruginosa infectious disease.
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Affiliation(s)
- Weichuan Xiong
- Department of Surgery, State University of New York (SUNY) Upstate Medical University, Syracuse, New York, USA
- Department of Respiratory and Critical Care Medicine, The First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi, People’s Republic of China
| | - Alexander Perna
- Department of Surgery, State University of New York (SUNY) Upstate Medical University, Syracuse, New York, USA
| | - Ikechukwu B. Jacob
- Department of Surgery, State University of New York (SUNY) Upstate Medical University, Syracuse, New York, USA
- Department of Microbiology and Immunology, State University of New York (SUNY) Upstate Medical University, Syracuse, New York, USA
| | | | - Guirong Wang
- Department of Surgery, State University of New York (SUNY) Upstate Medical University, Syracuse, New York, USA
- Department of Microbiology and Immunology, State University of New York (SUNY) Upstate Medical University, Syracuse, New York, USA
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Visser AN, Wankel SD, Frey C, Kappler A, Lehmann MF. Unchanged nitrate and nitrite isotope fractionation during heterotrophic and Fe(II)-mixotrophic denitrification suggest a non-enzymatic link between denitrification and Fe(II) oxidation. Front Microbiol 2022; 13:927475. [PMID: 36118224 PMCID: PMC9478938 DOI: 10.3389/fmicb.2022.927475] [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: 04/24/2022] [Accepted: 07/29/2022] [Indexed: 11/13/2022] Open
Abstract
Natural-abundance measurements of nitrate and nitrite (NOx) isotope ratios (δ15N and δ18O) can be a valuable tool to study the biogeochemical fate of NOx species in the environment. A prerequisite for using NOx isotopes in this regard is an understanding of the mechanistic details of isotope fractionation (15ε, 18ε) associated with the biotic and abiotic NOx transformation processes involved (e.g., denitrification). However, possible impacts on isotope fractionation resulting from changing growth conditions during denitrification, different carbon substrates, or simply the presence of compounds that may be involved in NOx reduction as co-substrates [e.g., Fe(II)] remain uncertain. Here we investigated whether the type of organic substrate, i.e., short-chained organic acids, and the presence/absence of Fe(II) (mixotrophic vs. heterotrophic growth conditions) affect N and O isotope fractionation dynamics during nitrate (NO3–) and nitrite (NO2–) reduction in laboratory experiments with three strains of putative nitrate-dependent Fe(II)-oxidizing bacteria and one canonical denitrifier. Our results revealed that 15ε and 18ε values obtained for heterotrophic (15ε-NO3–: 17.6 ± 2.8‰, 18ε-NO3–:18.1 ± 2.5‰; 15ε-NO2–: 14.4 ± 3.2‰) vs. mixotrophic (15ε-NO3–: 20.2 ± 1.4‰, 18ε-NO3–: 19.5 ± 1.5‰; 15ε-NO2–: 16.1 ± 1.4‰) growth conditions are very similar and fall within the range previously reported for classical heterotrophic denitrification. Moreover, availability of different short-chain organic acids (succinate vs. acetate), while slightly affecting the NOx reduction dynamics, did not produce distinct differences in N and O isotope effects. N isotope fractionation in abiotic controls, although exhibiting fluctuating results, even expressed transient inverse isotope dynamics (15ε-NO2–: –12.4 ± 1.3 ‰). These findings imply that neither the mechanisms ordaining cellular uptake of short-chain organic acids nor the presence of Fe(II) seem to systematically impact the overall N and O isotope effect during NOx reduction. The similar isotope effects detected during mixotrophic and heterotrophic NOx reduction, as well as the results obtained from the abiotic controls, may not only imply that the enzymatic control of NOx reduction in putative NDFeOx bacteria is decoupled from Fe(II) oxidation, but also that Fe(II) oxidation is indirectly driven by biologically (i.e., via organic compounds) or abiotically (catalysis via reactive surfaces) mediated processes co-occurring during heterotrophic denitrification.
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Affiliation(s)
- Anna-Neva Visser
- Aquatic and Isotope Biogeochemistry, Department of Environmental Sciences, Basel University, Basel, Switzerland
- *Correspondence: Anna-Neva Visser,
| | - Scott D. Wankel
- Stable Isotope Biogeochemistry, Marine Chemistry and Geochemistry, Woods Hole Oceanographic Institution, Falmouth, MA, United States
| | - Claudia Frey
- Aquatic and Isotope Biogeochemistry, Department of Environmental Sciences, Basel University, Basel, Switzerland
| | - Andreas Kappler
- Geomicrobiology, Center for Applied Geosciences, Eberhard Karls University, Tuebingen, Germany
- Cluster of Excellence: EXC 2124: Controlling Microbes to Fight Infection, Tuebingen, Germany
| | - Moritz F. Lehmann
- Aquatic and Isotope Biogeochemistry, Department of Environmental Sciences, Basel University, Basel, Switzerland
- Moritz F. Lehmann,
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12
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Tena-Garitaonaindia M, Ceacero-Heras D, Montoro MDMM, de Medina FS, Martínez-Augustin O, Daddaoua A. A Standardized Extract of Lentinula edodes Cultured Mycelium Inhibits Pseudomonas aeruginosa Infectivity Mechanisms. Front Microbiol 2022; 13:814448. [PMID: 35369436 PMCID: PMC8966770 DOI: 10.3389/fmicb.2022.814448] [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] [Received: 11/13/2021] [Accepted: 02/14/2022] [Indexed: 12/03/2022] Open
Abstract
The priority pathogen list of the World Health Organization classified Pseudomonas aeruginosa as the second top critical pathogen. Hence, the development of novel antibacterial strategies to tackle this bacterium is highly necessary. Herein we explore the potential antibacterial effect of a standardized extract of cultured mycelium of Lentinula edodes (AHCC®) on P. aeruginosa. AHCC® was found to inhibit the growth rate and biofilm formation of strain PAO1. No change in swarming was observed, but AHCC® hampered swimming and twitching motility. In accordance, a decreased expression of metabolism, growth, and biofilm formation genes was shown. AHCC® also diminished the levels of exotoxin A and bacteria inside IEC18 cells and the secretion of IL-6, IL-10 and TNF by infected macrophages. This effect was related to a reduced phosphorylation of MAPKs and to bacteria internalization. Taken together, our data suggest that AHCC® has a potential role to prevent P. aeruginosa infections and may lead to the development of new therapies.
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Affiliation(s)
- Mireia Tena-Garitaonaindia
- Department of Biochemistry and Molecular Biology II, Pharmacy School, University of Granada, Granada, Spain
| | - Diego Ceacero-Heras
- Department of Biochemistry and Molecular Biology II, Pharmacy School, University of Granada, Granada, Spain
| | - María Del Mar Maldonado Montoro
- Clinical Analysis Service, Hospital Campus de la Salud, Granada, Spain.,Instituto de Investigación Biosanitaria (IBS), Granada, Spain
| | - Fermín Sánchez de Medina
- Department of Pharmacology, School of Pharmacy, University of Granada, Granada, Spain.,Department of Pharmacology, Pharmacy School, University of Granada, Granada, Spain
| | - Olga Martínez-Augustin
- Department of Biochemistry and Molecular Biology II, Pharmacy School, University of Granada, Granada, Spain.,Instituto de Investigación Biosanitaria (IBS), Granada, Spain.,Department of Pharmacology, Pharmacy School, University of Granada, Granada, Spain.,Institute of Nutrition and Food Technology "José Mataix," Center of Biomedical Research, University of Granada, Granada, Spain
| | - Abdelali Daddaoua
- Department of Biochemistry and Molecular Biology II, Pharmacy School, University of Granada, Granada, Spain.,Instituto de Investigación Biosanitaria (IBS), Granada, Spain.,Institute of Nutrition and Food Technology "José Mataix," Center of Biomedical Research, University of Granada, Granada, Spain
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13
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Zhang Y, Tan H, Yang S, Huang Y, Cai S, Jian J, Cai J, Qin Q. The role of dctP gene in regulating colonization, adhesion and pathogenicity of Vibrio alginolyticus strain HY9901. JOURNAL OF FISH DISEASES 2022; 45:421-434. [PMID: 34931326 DOI: 10.1111/jfd.13571] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2021] [Revised: 11/29/2021] [Accepted: 12/03/2021] [Indexed: 06/14/2023]
Abstract
Vibriosis caused by Vibrio alginolyticus has severely affected the development of mariculture industry in recent decades. DctP, a tripartite ATP-independent periplasmic transporter solute-binding subunit, is thought to be one of the virulence factors in Vibrio. In this study, the results displayed no difference in morphological characteristics and growth between ΔdctP (dctP mutant strain) and WT (wild-type strain). Nevertheless, the ability of swarming motility, biofilm formation, ECPase formation, cell adhesion and colonized ability of ΔdctP significantly decreased compared to those of WT. The LD50 of ΔdctP significantly increased by 40-fold compared to that of WT. The transcriptome analysis demonstrated the deletion mutation of dctP could regulate the expression levels of 22 genes related to colonization, adhesion and pathogenicity in V. alginolyticus. The analysis of qRT-PCR showed the transcriptome data were reliable. These results reveal the effect of attenuated function of DctP on colonization, adherence and pathogenicity by controlling the expression of related gene.
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Affiliation(s)
- Yilin Zhang
- Guangdong Provincial Key Laboratory of Pathogenic Biology and Epidemiology for Aquatic Economic Animals & Key Laboratory of Control for Diseases of Aquatic Economic Animals of Guangdong Higher Education Institutes, Southern Marine Science and Engineering Guangdong Laboratory (Zhanjiang), Fisheries College of Guangdong Ocean University, Zhanjiang, China
| | - Huimin Tan
- Guangdong Provincial Key Laboratory of Pathogenic Biology and Epidemiology for Aquatic Economic Animals & Key Laboratory of Control for Diseases of Aquatic Economic Animals of Guangdong Higher Education Institutes, Southern Marine Science and Engineering Guangdong Laboratory (Zhanjiang), Fisheries College of Guangdong Ocean University, Zhanjiang, China
| | - Shiping Yang
- Guangdong Provincial Key Laboratory of Pathogenic Biology and Epidemiology for Aquatic Economic Animals & Key Laboratory of Control for Diseases of Aquatic Economic Animals of Guangdong Higher Education Institutes, Southern Marine Science and Engineering Guangdong Laboratory (Zhanjiang), Fisheries College of Guangdong Ocean University, Zhanjiang, China
| | - Yucong Huang
- Guangdong Provincial Key Laboratory of Pathogenic Biology and Epidemiology for Aquatic Economic Animals & Key Laboratory of Control for Diseases of Aquatic Economic Animals of Guangdong Higher Education Institutes, Southern Marine Science and Engineering Guangdong Laboratory (Zhanjiang), Fisheries College of Guangdong Ocean University, Zhanjiang, China
| | - Shuanghu Cai
- Guangdong Provincial Key Laboratory of Pathogenic Biology and Epidemiology for Aquatic Economic Animals & Key Laboratory of Control for Diseases of Aquatic Economic Animals of Guangdong Higher Education Institutes, Southern Marine Science and Engineering Guangdong Laboratory (Zhanjiang), Fisheries College of Guangdong Ocean University, Zhanjiang, China
- Guangdong Provincial Engineering Research Center for Aquatic Animal Health Assessment, Shenzhen Institute of Guangdong Ocean University, Shenzhen, China
| | - Jichang Jian
- Guangdong Provincial Key Laboratory of Pathogenic Biology and Epidemiology for Aquatic Economic Animals & Key Laboratory of Control for Diseases of Aquatic Economic Animals of Guangdong Higher Education Institutes, Southern Marine Science and Engineering Guangdong Laboratory (Zhanjiang), Fisheries College of Guangdong Ocean University, Zhanjiang, China
- Guangdong Provincial Engineering Research Center for Aquatic Animal Health Assessment, Shenzhen Institute of Guangdong Ocean University, Shenzhen, China
| | - Jia Cai
- Guangdong Provincial Key Laboratory of Pathogenic Biology and Epidemiology for Aquatic Economic Animals & Key Laboratory of Control for Diseases of Aquatic Economic Animals of Guangdong Higher Education Institutes, Southern Marine Science and Engineering Guangdong Laboratory (Zhanjiang), Fisheries College of Guangdong Ocean University, Zhanjiang, China
- Guangdong Provincial Engineering Research Center for Aquatic Animal Health Assessment, Shenzhen Institute of Guangdong Ocean University, Shenzhen, China
| | - Qiwei Qin
- College of Marine Sciences, South China Agricultural University, Guangzhou, China
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14
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Ducret V, Perron K, Valentini M. Role of Two-Component System Networks in Pseudomonas aeruginosa Pathogenesis. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2022; 1386:371-395. [PMID: 36258080 DOI: 10.1007/978-3-031-08491-1_14] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Two-component systems (TCS) are the largest family of signaling systems in the bacterial kingdom. They enable bacteria to cope with a wide range of environmental conditions via the sensing of stimuli and the transduction of the signal into an appropriate cellular adaptation response. Pseudomonas aeruginosa possesses one of the richest arrays of TCSs in bacteria and they have been the subject of intense investigation for more than 20 years. Most of the P. aeruginosa TCSs characterized to date affect its pathogenesis, via the regulation of virulence factors expression, modulation of the synthesis of antibiotic/antimicrobial resistance mechanisms, and/or via linking virulence to energy metabolism. Here, we give an overview of the current knowledge on P. aeruginosa TCSs, citing key examples for each of the above-mentioned regulatory actions. We then conclude by mentioning few small molecule inhibitors of P. aeruginosa TCSs that have shown an antimicrobial action in vitro.
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Affiliation(s)
- Verena Ducret
- Microbiology Unit, Department of Botany and Plant Biology, University of Geneva, Geneva, Switzerland
| | - Karl Perron
- Microbiology Unit, Department of Botany and Plant Biology, University of Geneva, Geneva, Switzerland
| | - Martina Valentini
- Department of Microbiology and Molecular Medicine, CMU, Faculty of Medicine, University of Geneva, Geneva, Switzerland.
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15
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Phylogenetic Analysis with Prediction of Cofactor or Ligand Binding for Pseudomonas aeruginosa PAS and Cache Domains. Microbiol Spectr 2021; 9:e0102621. [PMID: 34937179 PMCID: PMC8694187 DOI: 10.1128/spectrum.01026-21] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
PAS domains are omnipresent building blocks of multidomain proteins in all domains of life. Bacteria possess a variety of PAS domains in intracellular proteins and the related Cache domains in periplasmic or extracellular proteins. PAS and Cache domains are predominant in sensory systems, often carry cofactors or bind ligands, and serve as dimerization domains in protein association. To aid our understanding of the wide distribution of these domains, we analyzed the proteome of the opportunistic human pathogen Pseudomonas aeruginosa PAO1 in silico. The ability of this bacterium to survive under different environmental conditions, to switch between planktonic and sessile/biofilm lifestyle, or to evade stresses, notably involves c-di-GMP regulatory proteins or depends on sensory pathways involving multidomain proteins that possess PAS or Cache domains. Maximum likelihood phylogeny was used to group PAS and Cache domains on the basis of amino acid sequence. Conservation of cofactor- or ligand-coordinating amino acids aided by structure-based comparison was used to inform function. The resulting classification presented here includes PAS domains that are candidate binders of carboxylic acids, amino acids, fatty acids, flavin adenine dinucleotide (FAD), 4-hydroxycinnamic acid, and heme. These predictions are put in context to previously described phenotypic data, often generated from deletion mutants. The analysis predicts novel functions for sensory proteins and sheds light on functional diversification in a large set of proteins with similar architecture. IMPORTANCE To adjust to a variety of life conditions, bacteria typically use multidomain proteins, where the modular structure allows functional differentiation. Proteins responding to environmental cues and regulating physiological responses are found in chemotaxis pathways that respond to a wide range of stimuli to affect movement. Environmental cues also regulate intracellular levels of cyclic-di-GMP, a universal bacterial secondary messenger that is a key determinant of bacterial lifestyle and virulence. We study Pseudomonas aeruginosa, an organism known to colonize a broad range of environments that can switch lifestyle between the sessile biofilm and the planktonic swimming form. We have investigated the PAS and Cache domains, of which we identified 101 in 70 Pseudomonas aeruginosa PAO1 proteins, and have grouped these by phylogeny with domains of known structure. The resulting data set integrates sequence analysis and structure prediction to infer ligand or cofactor binding. With this data set, functional predictions for PAS and Cache domain-containing proteins are made.
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16
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Brandão A, Pires DP, Coppens L, Voet M, Lavigne R, Azeredo J. Differential transcription profiling of the phage LUZ19 infection process in different growth media. RNA Biol 2021; 18:1778-1790. [PMID: 33448239 PMCID: PMC8583145 DOI: 10.1080/15476286.2020.1870844] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2020] [Revised: 12/21/2020] [Accepted: 12/23/2020] [Indexed: 10/22/2022] Open
Abstract
RNA sequencing of phage-infected bacterial cultures offers a snapshot of transcriptional events occurring during the infection process, providing insights into the phage transcriptional organization as well as the bacterial response. To better mimic real environmental contexts, we performed RNA-seq of Pseudomonas aeruginosa PAO1 cultures infected with phage LUZ19 in a mammalian cell culture medium to better simulate a phage therapy event and the data were compared to lysogeny broth medium. Regardless of the media, phage LUZ19 induces significant transcriptional changes in the bacterial host over time, particularly during early infection (t = 5 min) and gradually shuts down bacterial transcription. In a common response in both media, 56 P. aeruginosa PAO1 genes are differentially transcribed and clustered into several functional categories such as metabolism, translation and transcription. Our data allowed us to tease apart a medium-specific response during infection from the identified infection-associated responses. This reinforces the concept that phages overtake bacterial transcriptome in a strict manner to gain control of the bacterial machinery and reallocate resources for infection, in this case overcoming the nutritional limitations of the mammalian cell culture medium. From a phage therapy perspective, this study contributes towards a better understanding of phage-host interaction in human physiological conditions and demonstrates the versatility of phage LUZ19 to adapt to different environments.
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Affiliation(s)
- Ana Brandão
- Centre of Biological Engineering, University of Minho, Braga, Portugal
- Laboratory of Gene Technology, KU Leuven, Leuven, Belgium
| | - Diana P. Pires
- Centre of Biological Engineering, University of Minho, Braga, Portugal
| | - Lucas Coppens
- Laboratory of Gene Technology, KU Leuven, Leuven, Belgium
| | - Marleen Voet
- Laboratory of Gene Technology, KU Leuven, Leuven, Belgium
| | - Rob Lavigne
- Laboratory of Gene Technology, KU Leuven, Leuven, Belgium
| | - Joana Azeredo
- Centre of Biological Engineering, University of Minho, Braga, Portugal
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17
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Wei Z, Xu Y, Xu Q, Cao W, Huang H, Liu H. Microbial Biosynthesis of L-Malic Acid and Related Metabolic Engineering Strategies: Advances and Prospects. Front Bioeng Biotechnol 2021; 9:765685. [PMID: 34660563 PMCID: PMC8511312 DOI: 10.3389/fbioe.2021.765685] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Accepted: 09/16/2021] [Indexed: 11/13/2022] Open
Abstract
Malic acid, a four-carbon dicarboxylic acid, is widely used in the food, chemical and medical industries. As an intermediate of the TCA cycle, malic acid is one of the most promising building block chemicals that can be produced from renewable sources. To date, chemical synthesis or enzymatic conversion of petrochemical feedstocks are still the dominant mode for malic acid production. However, with increasing concerns surrounding environmental issues in recent years, microbial fermentation for the production of L-malic acid was extensively explored as an eco-friendly production process. The rapid development of genetic engineering has resulted in some promising strains suitable for large-scale bio-based production of malic acid. This review offers a comprehensive overview of the most recent developments, including a spectrum of wild-type, mutant, laboratory-evolved and metabolically engineered microorganisms for malic acid production. The technological progress in the fermentative production of malic acid is presented. Metabolic engineering strategies for malic acid production in various microorganisms are particularly reviewed. Biosynthetic pathways, transport of malic acid, elimination of byproducts and enhancement of metabolic fluxes are discussed and compared as strategies for improving malic acid production, thus providing insights into the current state of malic acid production, as well as further research directions for more efficient and economical microbial malic acid production.
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Affiliation(s)
- Zhen Wei
- MOE Key Laboratory of Industrial Fermentation Microbiology, College of Biotechnology, Tianjin University of Science & Technology, Tianjin, China
| | - Yongxue Xu
- MOE Key Laboratory of Industrial Fermentation Microbiology, College of Biotechnology, Tianjin University of Science & Technology, Tianjin, China
| | - Qing Xu
- School of Food Science and Pharmaceutical Engineering, Nanjing Normal University, Nanjing, China
| | - Wei Cao
- MOE Key Laboratory of Industrial Fermentation Microbiology, College of Biotechnology, Tianjin University of Science & Technology, Tianjin, China.,Tianjin Engineering Research Center of Microbial Metabolism and Fermentation Process Control, Tianjin University of Science & Technology, Tianjin, China
| | - He Huang
- School of Food Science and Pharmaceutical Engineering, Nanjing Normal University, Nanjing, China
| | - Hao Liu
- MOE Key Laboratory of Industrial Fermentation Microbiology, College of Biotechnology, Tianjin University of Science & Technology, Tianjin, China.,Tianjin Engineering Research Center of Microbial Metabolism and Fermentation Process Control, Tianjin University of Science & Technology, Tianjin, China
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18
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Sarwar Z, Wang MX, Lundgren BR, Nomura CT. MifS, a DctB family histidine kinase, is a specific regulator of α-ketoglutarate response in Pseudomonas aeruginosa PAO1. MICROBIOLOGY-SGM 2021; 166:867-879. [PMID: 32553056 DOI: 10.1099/mic.0.000943] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
The C5-dicarboxylate α-ketoglutarate (α-KG) is a preferred nutrient source for the opportunistic pathogen Pseudomonas aeruginosa. However, very little is known about how P. aeruginosa detects and responds to α-KG in the environment. Our laboratory has previously shown that the MifS/MifR two-component signal transduction system regulates α-KG assimilation in P. aeruginosa PAO1. In an effort to better understand how this bacterium detects α-KG, we characterized the MifS sensor histidine kinase. In this study we show that although MifS is a homologue of the C4-dicarboxylate sensor DctB, it specifically responds to the C5-dicarboxylate α-KG. MifS activity increased >10-fold in the presence of α-KG, while the related C5-dicarboxylate glutarate caused only a 2-fold increase in activity. All other dicarboxylates tested did not show any significant effect on MifS activity. Homology modelling of the MifS sensor domain revealed a substrate binding pocket for α-KG. Using protein modelling and mutational analysis, we identified nine residues that are important for α-KG response, including one residue that determines the substrate specificity of MifS. Further, we found that MifS has a novel cytoplasmic linker domain that is required for α-KG response and is probably involved in signal transduction from the sensor domain to the cytoplasmic transmitter domain. Until this study, DctB family histidine kinases were known to only respond to C4-dicarboxylates. Our work shows that MifS is a novel member of the DctB family histidine kinase that specifically responds to α-KG.
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Affiliation(s)
- Zaara Sarwar
- Department of Biology, The College of New Jersey, Ewing, New Jersey, USA
| | - Michael X Wang
- Present address: Biomedical Sciences Graduate Program, University of California, San Diego, California, USA.,Department of Chemistry, The State University of New York, College of Environmental Science and Forestry, Syracuse, New York, USA
| | - Benjamin R Lundgren
- Department of Chemistry, The State University of New York, College of Environmental Science and Forestry, Syracuse, New York, USA
| | - Christopher T Nomura
- Center for Applied Microbiology, The State University of New York, College of Environmental Science and Forestry, Syracuse, New York, USA.,Department of Chemistry, The State University of New York, College of Environmental Science and Forestry, Syracuse, New York, USA
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19
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Lundgren BR, Shoytush JM, Scheel RA, Sain S, Sarwar Z, Nomura CT. Utilization of L-glutamate as a preferred or sole nutrient in Pseudomonas aeruginosa PAO1 depends on genes encoding for the enhancer-binding protein AauR, the sigma factor RpoN and the transporter complex AatJQMP. BMC Microbiol 2021; 21:83. [PMID: 33722201 PMCID: PMC7962211 DOI: 10.1186/s12866-021-02145-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Accepted: 03/04/2021] [Indexed: 11/10/2022] Open
Abstract
Background Glutamate and aspartate are preferred nutrients for a variety of microorganisms. In the case for many Pseudomonas spp., utilization of these amino acids is believed to be dependent on a transporter complex comprised of a periplasmic-solute binding protein (AatJ), two permease domains (AatQM) and an ATP-binding component (AatP). Notably, expression of this transporter complex is hypothesized to be regulated at the transcriptional level by the enhancer-binding protein AauR and the alternative sigma factor RpoN. The purpose of the current study was to determine the biological significance of the putative aatJ-aatQMP operon and its regulatory aauR and rpoN genes in the utilization of L-glutamate, L-glutamine, L-aspartate and L-asparagine in Pseudomonas aeruginosa PAO1. Results Deletion of the aatJ-aatQMP, aauR or rpoN genes did not affect the growth of P. aeruginosa PAO1 on L-glutamate, L-glutamine, L-aspartate and L-asparagine equally. Instead, only growth on L-glutamate as the sole carbon source was abolished with the deletion of any one of these genes. Interestingly, growth of the aauR mutant on L-glutamate was readily restored via plasmid-based expression of the aatQMP genes, suggesting that it is the function of AatQMP (and not AatJ) that is limiting in the absence of the aauR gene. Subsequent analysis of beta-galactosidase reporters revealed that both aatJ and aatQ were induced in response to L-glutamate, L-glutamine, L-aspartate or L-asparagine in a manner dependent on the aauR and rpoN genes. In addition, both aatJ and aatQ were expressed at reduced levels in the absence of the inducing-amino acids and the regulatory aauR and rpoN genes. The expression of the aatJ-aatQMP genes is, therefore, multifaceted. Lastly, the expression levels of aatJ were significantly higher (> 5 fold) than that of aatQ under all tested conditions. Conclusions The primary function of AauR in P. aeruginosa PAO1 is to activate expression of the aatJ-aatQMP genes in response to exogenous acidic amino acids and their amide derivatives. Importantly, it is the AauR-RpoN mediated induction of the aatQMP genes that is the pivotal factor enabling P. aeruginosa PAO1 to effectively utilize or consume L-glutamate as a sole or preferred nutrient.
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Affiliation(s)
- Benjamin R Lundgren
- Department of Chemistry, State University of New York - College of Environmental Science and Forestry, Syracuse, 1 Forestry Drive, Syracuse, New York, 13210, USA.
| | - Joseph M Shoytush
- Department of Chemistry, State University of New York - College of Environmental Science and Forestry, Syracuse, 1 Forestry Drive, Syracuse, New York, 13210, USA
| | - Ryan A Scheel
- Department of Chemistry, State University of New York - College of Environmental Science and Forestry, Syracuse, 1 Forestry Drive, Syracuse, New York, 13210, USA
| | - Safreen Sain
- Department of Biology, The College of New Jersey, 2000 Pennington Road, Ewing, NJ, 08628, USA
| | - Zaara Sarwar
- Department of Biology, The College of New Jersey, 2000 Pennington Road, Ewing, NJ, 08628, USA
| | - Christopher T Nomura
- Department of Biological Sciences, University of Idaho, 875 Perimeter Drive, Moscow, ID, 83844, USA
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20
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Song Y, Luo G, Zhu Y, Li T, Li C, He L, Zhao N, Zhao C, Yang J, Huang Q, Mu X, Tang X, Kang M, Wu S, He Y, Bao R. Pseudomonas aeruginosa antitoxin HigA functions as a diverse regulatory factor by recognizing specific pseudopalindromic DNA motifs. Environ Microbiol 2020; 23:1541-1558. [PMID: 33346387 DOI: 10.1111/1462-2920.15365] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Revised: 12/15/2020] [Accepted: 12/16/2020] [Indexed: 02/05/2023]
Abstract
Type II toxin-antitoxin (TA) systems modulate many essential cellular processes in prokaryotic organisms. Recent studies indicate certain type II antitoxins also transcriptionally regulate other genes, besides neutralizing toxin activity. Herein, we investigated the diverse transcriptional repression properties of type II TA antitoxin PaHigA from Pseudomonas aeruginosa. Biochemical and functional analyses showed that PaHigA recognized variable pseudopalindromic DNA sequences and repressed expression of multiple genes. Furthermore, we presented high resolution structures of apo-PaHigA, PaHigA-PhigBA and PaHigA-Ppa2440 complex, describing how the rearrangements of the HTH domain accounted for the different DNA-binding patterns among HigA homologues. Moreover, we demonstrated that the N-terminal loop motion of PaHigA was associated with its apo and DNA-bound states, reflecting a switch mechanism regulating HigA antitoxin function. Collectively, this work extends our understanding of how the PaHigB/HigA system regulates multiple metabolic pathways to balance the growth and stress response in P. aeruginosa and could guide further development of anti-TA oriented strategies for pathogen treatment.
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Affiliation(s)
- Yingjie Song
- Center of Infectious Diseases, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University and Collaborative Innovation Center, Chengdu, China
| | - Guihua Luo
- Center of Infectious Diseases, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University and Collaborative Innovation Center, Chengdu, China
| | - Yibo Zhu
- Center of Infectious Diseases, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University and Collaborative Innovation Center, Chengdu, China
| | - Tao Li
- Center of Infectious Diseases, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University and Collaborative Innovation Center, Chengdu, China
| | - Changcheng Li
- Center of Infectious Diseases, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University and Collaborative Innovation Center, Chengdu, China
| | - Lihui He
- Center of Infectious Diseases, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University and Collaborative Innovation Center, Chengdu, China
| | - Ninglin Zhao
- Center of Infectious Diseases, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University and Collaborative Innovation Center, Chengdu, China
| | - Chang Zhao
- Center of Infectious Diseases, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University and Collaborative Innovation Center, Chengdu, China
| | - Jing Yang
- Center of Infectious Diseases, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University and Collaborative Innovation Center, Chengdu, China
| | - Qin Huang
- Center of Infectious Diseases, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University and Collaborative Innovation Center, Chengdu, China
| | - Xingyu Mu
- Center of Infectious Diseases, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University and Collaborative Innovation Center, Chengdu, China
| | - Xinyue Tang
- Center of Infectious Diseases, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University and Collaborative Innovation Center, Chengdu, China
| | - Mei Kang
- Department of Laboratory medicine, West China Hospital, Sichuan University, Chengdu, China
| | - Siying Wu
- Department of Laboratory medicine, West China Hospital, Sichuan University, Chengdu, China
| | - Yongxing He
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, China
| | - Rui Bao
- Center of Infectious Diseases, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University and Collaborative Innovation Center, Chengdu, China
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21
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Cao W, Yan L, Li M, Liu X, Xu Y, Xie Z, Liu H. Identification and engineering a C4-dicarboxylate transporter for improvement of malic acid production in Aspergillus niger. Appl Microbiol Biotechnol 2020; 104:9773-9783. [DOI: 10.1007/s00253-020-10932-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2020] [Revised: 08/12/2020] [Accepted: 09/23/2020] [Indexed: 12/13/2022]
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22
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Takeuchi M, Kuwahara H, Murakami T, Takahashi K, Kajitani R, Toyoda A, Itoh T, Ohkuma M, Hongoh Y. Parallel reductive genome evolution in Desulfovibrio ectosymbionts independently acquired by Trichonympha protists in the termite gut. THE ISME JOURNAL 2020; 14:2288-2301. [PMID: 32483307 PMCID: PMC7608387 DOI: 10.1038/s41396-020-0688-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/05/2020] [Revised: 05/13/2020] [Accepted: 05/21/2020] [Indexed: 12/13/2022]
Abstract
Several Trichonympha protist species in the termite gut have independently acquired Desulfovibrio ectosymbionts in apparently different stages of symbiosis. Here, we obtained the near-complete genome sequence of Desulfovibrio phylotype ZnDsv-02, which attaches to the surface of Trichonympha collaris cells, and compared it with a previously obtained genome sequence of 'Candidatus Desulfovibrio trichonymphae' phylotype Rs-N31, which is almost completely embedded in the cytoplasm of Trichonympha agilis. Single-nucleotide polymorphism analysis indicated that although Rs-N31 is almost clonal, the ZnDsv-02 population on a single host cell is heterogeneous. Despite these differences, the genome of ZnDsv-02 has been reduced to 1.6 Mb, which is comparable to that of Rs-N31 (1.4 Mb), but unlike other known ectosymbionts of protists with a genome similar in size to their free-living relatives. Except for the presence of a lactate utilization pathway, cell-adhesion components and anti-phage defense systems in ZnDsv-02, the overall gene-loss pattern between the two genomes is very similar, including the loss of genes responsive to environmental changes. Our study suggests that genome reduction can occur in ectosymbionts, even when they can be transmitted horizontally and obtain genes via lateral transfer, and that the symbiont genome size depends heavily on their role in the symbiotic system.
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Affiliation(s)
- Mariko Takeuchi
- School of Life Science and Technology, Tokyo Institute of Technology, Tokyo, 152-8550, Japan
| | - Hirokazu Kuwahara
- School of Life Science and Technology, Tokyo Institute of Technology, Tokyo, 152-8550, Japan.
| | - Takumi Murakami
- School of Life Science and Technology, Tokyo Institute of Technology, Tokyo, 152-8550, Japan
- Department of Informatics, National Institute of Genetics, Shizuoka, 411-8540, Japan
- Advanced Genomics Center, National Institute of Genetics, Shizuoka, 411-8540, Japan
| | - Kazuki Takahashi
- School of Life Science and Technology, Tokyo Institute of Technology, Tokyo, 152-8550, Japan
| | - Rei Kajitani
- School of Life Science and Technology, Tokyo Institute of Technology, Tokyo, 152-8550, Japan
| | - Atsushi Toyoda
- Advanced Genomics Center, National Institute of Genetics, Shizuoka, 411-8540, Japan
- Department of Genomics and Evolutionary Biology, National Institute of Genetics, Shizuoka, 411-8540, Japan
| | - Takehiko Itoh
- School of Life Science and Technology, Tokyo Institute of Technology, Tokyo, 152-8550, Japan
| | - Moriya Ohkuma
- Japan Collection of Microorganisms, RIKEN BioResource Research Center, Tsukuba, 305-0074, Japan
| | - Yuichi Hongoh
- School of Life Science and Technology, Tokyo Institute of Technology, Tokyo, 152-8550, Japan.
- Japan Collection of Microorganisms, RIKEN BioResource Research Center, Tsukuba, 305-0074, Japan.
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23
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Paraburkholderia phymatum STM815 σ54 Controls Utilization of Dicarboxylates, Motility, and T6SS-b Expression. NITROGEN 2020. [DOI: 10.3390/nitrogen1020008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Rhizobia have two major life styles, one as free-living bacteria in the soil, and the other as bacteroids within the root/stem nodules of host legumes where they convert atmospheric nitrogen into ammonia. In the soil, rhizobia have to cope with changing and sometimes stressful environmental conditions, such as nitrogen limitation. In the beta-rhizobial strain Paraburkholderia phymatum STM815, the alternative sigma factor σ54 (or RpoN) has recently been shown to control nitrogenase activity during symbiosis with Phaseolus vulgaris. In this study, we determined P. phymatum’s σ54 regulon under nitrogen-limited free-living conditions. Among the genes significantly downregulated in the absence of σ54, we found a C4-dicarboxylate carrier protein (Bphy_0225), a flagellar biosynthesis cluster (Bphy_2926-64), and one of the two type VI secretion systems (T6SS-b) present in the P. phymatum STM815 genome (Bphy_5978-97). A defined σ54 mutant was unable to grow on C4 dicarboxylates as sole carbon source and was less motile compared to the wild-type strain. Both defects could be complemented by introducing rpoNin trans. Using promoter reporter gene fusions, we also confirmed that the expression of the T6SS-b cluster is regulated by σ54. Accordingly, we show that σ54 affects in vitro competitiveness of P. phymatum STM815 against Paraburkholderia diazotrophica.
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24
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Mould DL, Botelho NJ, Hogan DA. Intraspecies Signaling between Common Variants of Pseudomonas aeruginosa Increases Production of Quorum-Sensing-Controlled Virulence Factors. mBio 2020; 11:e01865-20. [PMID: 32843558 PMCID: PMC7448281 DOI: 10.1128/mbio.01865-20] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Accepted: 07/17/2020] [Indexed: 12/18/2022] Open
Abstract
The opportunistic pathogen Pseudomonas aeruginosa damages hosts through the production of diverse secreted products, many of which are regulated by quorum sensing (QS). The lasR gene, which encodes a central QS regulator, is frequently mutated in clinical isolates from chronic infections, and loss of LasR function (LasR-) generally impairs the activity of downstream QS regulators RhlR and PqsR. We found that in cocultures containing LasR+ and LasR- strains, LasR- strains hyperproduce the RhlR/RhlI-regulated antagonistic factors pyocyanin and rhamnolipids in diverse models and media and in different strain backgrounds. Diffusible QS autoinducers produced by the wild type were not required for this effect. Using transcriptomics, genetics, and biochemical approaches, we uncovered a reciprocal interaction between wild-type and lasR mutant pairs wherein the iron-scavenging siderophore pyochelin produced by the lasR mutant induced citrate release and cross-feeding from the wild type. Citrate, a metabolite often secreted in low iron environments, stimulated RhlR signaling and RhlI levels in LasR-but not in LasR+ strains. These studies reveal the potential for complex interactions between recently diverged, genetically distinct isolates within populations from single chronic infections.IMPORTANCE Coculture interactions between lasR loss-of-function and LasR+ Pseudomonas aeruginosa strains may explain the worse outcomes associated with the presence of LasR- strains. More broadly, this report illustrates how interactions within a genotypically diverse population, similar to those that frequently develop in natural settings, can promote unpredictably high virulence factor production.
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Affiliation(s)
- Dallas L Mould
- Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA
| | - Nico J Botelho
- Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA
| | - Deborah A Hogan
- Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA
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Szczerba H, Dudziak K, Krawczyk M, Targoński Z. A Genomic Perspective on the Potential of Wild-Type Rumen Bacterium Enterobacter sp. LU1 as an Industrial Platform for Bio-Based Succinate Production. Int J Mol Sci 2020; 21:ijms21144835. [PMID: 32650546 PMCID: PMC7402333 DOI: 10.3390/ijms21144835] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Revised: 07/03/2020] [Accepted: 07/05/2020] [Indexed: 12/31/2022] Open
Abstract
Enterobacter sp. LU1, a wild-type bacterium originating from goat rumen, proved to be a potential succinic acid producer in previous studies. Here, the first complete genome of this strain was obtained and analyzed from a biotechnological perspective. A hybrid sequencing approach combining short (Illumina MiSeq) and long (ONT MinION) reads allowed us to obtain a single continuous chromosome 4,636,526 bp in size, with an average 55.6% GC content that lacked plasmids. A total of 4425 genes, including 4283 protein-coding genes, 25 ribosomal RNA (rRNA)-, 84 transfer RNA (tRNA)-, and 5 non-coding RNA (ncRNA)-encoding genes and 49 pseudogenes, were predicted. It has been shown that genes involved in transport and metabolism of carbohydrates and amino acids and the transcription process constitute the major group of genes, according to the Clusters of Orthologous Groups of proteins (COGs) database. The genetic ability of the LU1 strain to metabolize a wide range of industrially relevant carbon sources has been confirmed. The genome exploration indicated that Enterobacter sp. LU1 possesses all genes that encode the enzymes involved in the glycerol metabolism pathway. It has also been shown that succinate can be produced as an end product of fermentation via the reductive branch of the tricarboxylic acid cycle (TCA) and the glyoxylate pathway. The transport system involved in succinate excretion into the growth medium and the genes involved in the response to osmotic and oxidative stress have also been recognized. Furthermore, three intact prophage regions ~70.3 kb, ~20.9 kb, and ~49.8 kb in length, 45 genomic islands (GIs), and two clustered regularly interspaced short palindromic repeats (CRISPR) were recognized in the genome. Sequencing and genome analysis of Enterobacter sp. LU1 confirms many earlier results based on physiological experiments and provides insight into their genetic background. All of these findings illustrate that the LU1 strain has great potential to be an efficient platform for bio-based succinate production.
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Affiliation(s)
- Hubert Szczerba
- Department of Biotechnology, Microbiology and Human Nutrition, University of Life Sciences in Lublin, 20-704 Lublin, Poland;
- Correspondence: ; Tel.: +48-81-462-3402
| | - Karolina Dudziak
- Chair and Department of Biochemistry and Molecular Biology, Medical University of Lublin, 20-093 Lublin, Poland;
| | | | - Zdzisław Targoński
- Department of Biotechnology, Microbiology and Human Nutrition, University of Life Sciences in Lublin, 20-704 Lublin, Poland;
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A Disjointed Pathway for Malonate Degradation by Rhodopseudomonas palustris. Appl Environ Microbiol 2020; 86:AEM.00631-20. [PMID: 32220835 DOI: 10.1128/aem.00631-20] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2020] [Accepted: 03/17/2020] [Indexed: 11/20/2022] Open
Abstract
The purple nonsulfur phototrophic bacterium Rhodopseudomonas palustris strain CGA009 uses the three-carbon dicarboxylic acid malonate as the sole carbon source under phototrophic conditions. However, this bacterium grows extremely slowly on this compound and does not have operons for the two pathways for malonate degradation that have been detected in other bacteria. Many bacteria grow on a spectrum of carbon sources, some of which are classified as poor growth substrates because they support low growth rates. This trait is rarely addressed in the literature, but slow growth is potentially useful in biotechnological applications where it is imperative for bacteria to divert cellular resources to value-added products rather than to growth. This prompted us to explore the genetic and physiological basis for the slow growth of R. palustris with malonate as a carbon source. There are two unlinked genes annotated as encoding a malonyl coenzyme A (malonyl-CoA) synthetase (MatB) and a malonyl-CoA decarboxylase (MatA) in the genome of R. palustris, which we verified as having the predicted functions. Additionally, two tripartite ATP-independent periplasmic transporters (TRAP systems) encoded by rpa2047 to rpa2049 and rpa2541 to rpa2543 were needed for optimal growth on malonate. Most of these genes were expressed constitutively during growth on several carbon sources, including malonate. Our data indicate that R. palustris uses a piecemeal approach to growing on malonate. The data also raise the possibility that this bacterium will evolve to use malonate efficiently if confronted with an appropriate selection pressure.IMPORTANCE There is interest in understanding how bacteria metabolize malonate because this three-carbon dicarboxylic acid can serve as a building block in bioengineering applications to generate useful compounds that have an odd number of carbons. We found that the phototrophic bacterium Rhodopseudomonas palustris grows extremely slowly on malonate. We identified two enzymes and two TRAP transporters involved in the uptake and metabolism of malonate, but some of these elements are apparently not very efficient. R. palustris cells growing with malonate have the potential to be excellent biocatalysts, because cells would be able to divert cellular resources to the production of value-added compounds instead of using them to support rapid growth. In addition, our results suggest that R. palustris is a candidate for directed evolution studies to improve growth on malonate and to observe the kinds of genetic adaptations that occur to make a metabolic pathway operate more efficiently.
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Ma Y, Li L, Awasthi MK, Tian H, Lu M, Megharaj M, Pan Y, He W. Time-course transcriptome analysis reveals the mechanisms of Burkholderia sp. adaptation to high phenol concentrations. Appl Microbiol Biotechnol 2020; 104:5873-5887. [PMID: 32415321 DOI: 10.1007/s00253-020-10672-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2020] [Revised: 04/28/2020] [Accepted: 05/05/2020] [Indexed: 01/02/2023]
Abstract
Microbial tolerance to phenolic pollutants is the key to their efficient biodegradation. However, the metabolic mechanisms that allow some microorganisms to adapt to high phenol concentrations remain unclear. In this study, to reveal the underlying mechanisms of how Burkholderia sp. adapt to high phenol concentrations, the strain's tolerance ability and time-course transcriptome in combination with cell phenotype were evaluated. Surprisingly, Burkholderia sp. still grew normally after a long adaptation to a relatively high phenol concentration (1500 mg/L) and exhibited some time-dependent changes compared to unstressed cells prior to the phenol addition. Time-course transcriptome analysis results revealed that the mechanism of adaptations to phenol was an evolutionary process that transitioned from tolerance to positive degradation through precise gene regulation at appropriate times. Specifically, basal stress gene expression was upregulated and contributed to phenol tolerance, which involved stress, DNA repair, membrane, efflux pump and antioxidant protein-coding genes, while a phenol degradation gene cluster was specifically induced. Interestingly, both the catechol and protocatechuate branches of the β-ketoadipate pathway contributed to the early stage of phenol degradation, but only the catechol branch was used in the late stage. In addition, pathways involving flagella, chemotaxis, ATP-binding cassette transporters and two-component systems were positively associated with strain survival under phenolic stress. This study provides the first insights into the specific response of Burkholderia sp. to high phenol stress and shows potential for application in remediation of polluted environments. KEY POINTS: • Shock, DNA repair and antioxidant-related genes contributed to phenol tolerance. • β-Ketoadipate pathway branches differed at different stages of phenol degradation. • Adaptation mechanisms transitioned from negative tolerance to positive degradation.
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Affiliation(s)
- Yinghui Ma
- Microbiology Institute of Shaanxi, Shaanxi Academy of Sciences, Xi'an, 710043, Shaanxi, PR China.,College of Natural Resources and Environment, Key Laboratory of Plant Nutrition and Agro-environment in Northwest China, Ministry of Agriculture, Northwest A&F University, Yangling, 712100, Shaanxi, PR China
| | - Lijun Li
- Microbiology Institute of Shaanxi, Shaanxi Academy of Sciences, Xi'an, 710043, Shaanxi, PR China.
| | - Mukesh Kumar Awasthi
- College of Natural Resources and Environment, Key Laboratory of Plant Nutrition and Agro-environment in Northwest China, Ministry of Agriculture, Northwest A&F University, Yangling, 712100, Shaanxi, PR China
| | - Haixia Tian
- College of Natural Resources and Environment, Key Laboratory of Plant Nutrition and Agro-environment in Northwest China, Ministry of Agriculture, Northwest A&F University, Yangling, 712100, Shaanxi, PR China
| | - Meihuan Lu
- Microbiology Institute of Shaanxi, Shaanxi Academy of Sciences, Xi'an, 710043, Shaanxi, PR China
| | - Mallavarapu Megharaj
- Global Centre for Environmental Remediation, Faculty of Science, University of Newcastle, University Drive, Callaghan, NSW, 2308, Australia
| | - Yalei Pan
- Shaanxi Collaborative Innovation Center of Chinese Medicine Resources Industrialization, Shaanxi University of Chinese Medicine, Xianyang, 712046, PR China
| | - Wenxiang He
- College of Natural Resources and Environment, Key Laboratory of Plant Nutrition and Agro-environment in Northwest China, Ministry of Agriculture, Northwest A&F University, Yangling, 712100, Shaanxi, PR China.
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28
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Briki A, Kaboré K, Olmos E, Bosselaar S, Blanchard F, Fick M, Guedon E, Fournier F, Delaunay S. Corynebacterium glutamicum, a natural overproducer of succinic acid? Eng Life Sci 2020; 20:205-215. [PMID: 32874184 PMCID: PMC7447883 DOI: 10.1002/elsc.201900141] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Revised: 01/03/2020] [Accepted: 01/03/2020] [Indexed: 01/09/2023] Open
Abstract
Corynebacterium glutamicum is well known as an important industrial amino acid producer. For a few years, its ability to produce organic acids, under micro-aerobic or anaerobic conditions was demonstrated. This study is focused on the identification of the culture parameters influencing the organic acids production and, in particular, the succinate production, by this bacterium. Corynebacterium glutamicum 2262, used throughout this study, was a wild-type strain, which was not genetically designed for the production of succinate. The oxygenation level and the residual glucose concentration appeared as two critical parameters for the organic acids production. The maximal succinate concentration (4.9 g L-1) corresponded to the lower kLa value of 5 h-1. Above 5 h-1, a transient accumulation of the succinate was observed. Interestingly, the stop in the succinate production was concomitant with a lower threshold glucose concentration of 9 g L-1. Taking into account this threshold, a fed-batch culture was performed to optimize the succinate production with C. glutamicum 2262. The results showed that this wild-type strain was able to produce 93.6 g L-1 of succinate, which is one of the highest concentration reported in the literature.
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Affiliation(s)
- Amani Briki
- Laboratoire Réactions et Génie des ProcédésCNRSVandoeuvre CedexFrance
- Laboratoire Réactions et Génie des ProcédésUniversité de LorraineVandoeuvre CedexFrance
| | - Karim Kaboré
- Laboratoire Réactions et Génie des ProcédésCNRSVandoeuvre CedexFrance
- Laboratoire Réactions et Génie des ProcédésUniversité de LorraineVandoeuvre CedexFrance
| | - Eric Olmos
- Laboratoire Réactions et Génie des ProcédésCNRSVandoeuvre CedexFrance
- Laboratoire Réactions et Génie des ProcédésUniversité de LorraineVandoeuvre CedexFrance
| | - Sabine Bosselaar
- Laboratoire Réactions et Génie des ProcédésCNRSVandoeuvre CedexFrance
- Laboratoire Réactions et Génie des ProcédésUniversité de LorraineVandoeuvre CedexFrance
| | - Fabrice Blanchard
- Laboratoire Réactions et Génie des ProcédésCNRSVandoeuvre CedexFrance
- Laboratoire Réactions et Génie des ProcédésUniversité de LorraineVandoeuvre CedexFrance
| | - Michel Fick
- Laboratoire Réactions et Génie des ProcédésCNRSVandoeuvre CedexFrance
- Laboratoire Réactions et Génie des ProcédésUniversité de LorraineVandoeuvre CedexFrance
| | - Emmanuel Guedon
- Laboratoire Réactions et Génie des ProcédésCNRSVandoeuvre CedexFrance
- Laboratoire Réactions et Génie des ProcédésUniversité de LorraineVandoeuvre CedexFrance
| | - Frantz Fournier
- Laboratoire Réactions et Génie des ProcédésCNRSVandoeuvre CedexFrance
- Laboratoire Réactions et Génie des ProcédésUniversité de LorraineVandoeuvre CedexFrance
| | - Stéphane Delaunay
- Laboratoire Réactions et Génie des ProcédésCNRSVandoeuvre CedexFrance
- Laboratoire Réactions et Génie des ProcédésUniversité de LorraineVandoeuvre CedexFrance
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29
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Albuquerque L, Castelhano N, Raposo P, Froufe HJC, Tiago I, Severino R, Roxo I, Gregório I, Barroso C, Egas C, da Costa MS. Comparative genome sequence analysis of several species in the genus Tepidimonas and the description of a novel species Tepidimonas charontis sp. nov. Int J Syst Evol Microbiol 2020; 70:1596-1604. [PMID: 32228748 PMCID: PMC7386788 DOI: 10.1099/ijsem.0.003942] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2019] [Revised: 10/22/2019] [Accepted: 12/06/2019] [Indexed: 11/18/2022] Open
Abstract
We performed high-quality genome sequencing of eight strains of the species of the genus Tepidimonas and examined the genomes of closely related strains from the databases to understand why Tepidimonas taiwanensis is the only strain of this genus that utilizes glucose and fructose for growth. We found that the assimilation of these hexoses by T. taiwanensis was due to the presence of two transporters that are absent in all other genomes of strains of members of the genus Tepidimonas examined. Some strains lack genes coding for glucokinase, but the Embden-Meyerhof-Parnas pathway appears to be otherwise complete. The pentose phosphate pathway has a complete set of genes, but genes of the Entner-Doudoroff pathway were not identified in the genomes of any of the strains examined. Genome analysis using average nucleotide identity (ANIb), digital DNA-DNA hybridization (dDDH), average amino acid identity (AAI) and phylogenetic analysis of 400 conserved genes was performed to assess the taxonomic classification of the organisms. Two isolates of the genus Tepidimonas from the hot spring at São Pedro do Sul, Portugal, designated SPSP-6T and SPSPC-18 were also examined in this study. These organisms are mixotrophic, have an optimum growth temperature of about 50 ºC, utilize several organic acids and amino acids for growth but do not grow on sugars. Distinctive phenotypic, 16S rRNA gene sequence and genomic characteristics of strains SPSP-6T and SPSPC-18 lead us to propose a novel species based on strain SPSP-6T for which we recommend the name Tepidimonas charontis sp. nov. (=CECT 9683T=LMG 30884T).
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Affiliation(s)
- Luciana Albuquerque
- Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504 Coimbra, Portugal
| | - Nadine Castelhano
- Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504 Coimbra, Portugal
| | - Pedro Raposo
- Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504 Coimbra, Portugal
| | - Hugo J. C. Froufe
- Next Generation Sequencing Unit, Biocant, BiocantPark, Núcleo 04, Lote 8, 3060-197 Cantanhede, Portugal
| | - Igor Tiago
- Center for Functional Ecology, University of Coimbra, 3000-456, Coimbra, Portugal
| | - Rita Severino
- Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504 Coimbra, Portugal
| | - Inês Roxo
- Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504 Coimbra, Portugal
| | - Inês Gregório
- Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504 Coimbra, Portugal
| | - Cristina Barroso
- Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504 Coimbra, Portugal
- Next Generation Sequencing Unit, Biocant, BiocantPark, Núcleo 04, Lote 8, 3060-197 Cantanhede, Portugal
| | - Conceição Egas
- Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504 Coimbra, Portugal
- Next Generation Sequencing Unit, Biocant, BiocantPark, Núcleo 04, Lote 8, 3060-197 Cantanhede, Portugal
| | - Milton S. da Costa
- Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504 Coimbra, Portugal
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30
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Rubio-Gómez JM, Santiago CM, Udaondo Z, Garitaonaindia MT, Krell T, Ramos JL, Daddaoua A. Full Transcriptomic Response of Pseudomonas aeruginosa to an Inulin-Derived Fructooligosaccharide. Front Microbiol 2020; 11:202. [PMID: 32153524 PMCID: PMC7044273 DOI: 10.3389/fmicb.2020.00202] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Accepted: 01/28/2020] [Indexed: 01/22/2023] Open
Abstract
Pseudomonas aeruginosa is an ubiquitous gram-negative opportunistic human pathogen which is not considered part of the human commensal gut microbiota. However, depletion of the intestinal microbiota (Dysbiosis) following antibiotic treatment facilitates the colonization of the intestinal tract by Multidrug-Resistant P. aeruginosa. One possible strategy is based on the use of functional foods with prebiotic activity. The bifidogenic effect of the prebiotic inulin and its hydrolyzed form (fructooligosaccharide: FOS) is well established since they promote the growth of specific beneficial (probiotic) gut bacteria such as bifidobacteria. Previous studies of the opportunistic nosocomial pathogen Pseudomonas aeruginosa PAO1 have shown that inulin and to a greater extent FOS reduce growth and biofilm formation, which was found to be due to a decrease in motility and exotoxin secretion. However, the transcriptional basis for these phenotypic alterations remains unclear. To address this question we conducted RNA-sequence analysis. Changes in the transcript level induced by inulin and FOS were similar, but a set of transcript levels were increased in response to inulin and reduced in the presence of FOS. In the presence of inulin or FOS, 260 and 217 transcript levels, respectively, were altered compared to the control to which no polysaccharide was added. Importantly, changes in transcript levels of 57 and 83 genes were found to be specific for either inulin or FOS, respectively, indicating that both compounds trigger different changes. Gene pathway analyses of differentially expressed genes (DEG) revealed a specific FOS-mediated reduction in transcript levels of genes that participate in several canonical pathways involved in metabolism and growth, motility, biofilm formation, β-lactamase resistance, and in the modulation of type III and VI secretion systems; results that have been partially verified by real time quantitative PCR measurements. Moreover, we have identified a genomic island formed by a cluster of 15 genes, encoding uncharacterized proteins, which were repressed in the presence of FOS. The analysis of isogenic mutants has shown that genes of this genomic island encode proteins involved in growth, biofilm formation and motility. These results indicate that FOS selectively modulates bacterial pathogenicity by interfering with different signaling pathways.
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Affiliation(s)
- José Manuel Rubio-Gómez
- Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas, Department of Pharmacology, School of Pharmacy, University of Granada, Granada, Spain
| | - Carlos Molina Santiago
- Department of Microbiology, Instituto de Hortofruticultura Subtropical y Mediterránea "La Mayora", University of Málaga, Málaga, Spain
| | - Zulema Udaondo
- Department of Biomedical Informatics, University of Arkansas for Medical Sciences, Little Rock, AR, United States
| | - Mireia Tena Garitaonaindia
- Department of Biochemistry and Molecular Biology II, School of Pharmacy, University of Granada, Granada, Spain
| | - Tino Krell
- Department of Environmental Protection, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, Granada, Spain
| | - Juan-Luis Ramos
- Department of Environmental Protection, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, Granada, Spain
| | - Abdelali Daddaoua
- Department of Biochemistry and Molecular Biology II, School of Pharmacy, University of Granada, Granada, Spain
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Dutta S, Yu SM, Jeong SC, Lee YH. High-throughput analysis of genes involved in biocontrol performance of Pseudomonas fluorescens NBC275 against Gray mold. J Appl Microbiol 2019; 128:265-279. [PMID: 31574191 DOI: 10.1111/jam.14475] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2019] [Revised: 09/01/2019] [Accepted: 09/17/2019] [Indexed: 01/16/2023]
Abstract
AIMS Many physiological and microbial characteristics influence the biocontrol performance of the biological control agents (BCAs) in agricultural fields. To implement effective biocontrol, the contribution of specific genes, mechanisms and traits to the biocontrol performance of BCAs need to be characterized and explored in greater detail. METHODS AND RESULTS In this study, a transposon (Tn) mutant library using the BCA Pseudomonas fluorescens NBC275 (Pf275) was generated to explore genes and bacterial characteristics involved in antifungal activity and biocontrol performance. Among the Tn mutants, 205 strains showing variations in antifungal activity compared to wild-type (WT) were selected and further analysed for biocontrol efficacy against gray mold in pepper fruits. The genes involved in pyoverdine biosynthesis (pvdI and pvdD) and chitin-binding protein (gbpA) played essential roles in the antifungal activity and biocontrol capacity of Pf275. In addition, a mutation in phlD completely abolished the antifungal activity and significantly suppressed the biocontrol ability of the strain. Genes affecting antifungal activity of Pf275 significantly influenced swimming motility, which was identified as an important trait for the biocontrol ability of the bacterial strain. CONCLUSIONS Overall, our results suggest that antifungal compound production, siderophore biosynthesis and swimming motility synergistically contribute to Pf275 biocontrol performance. The utility of this library was demonstrated by identifying genes for antagonism and biocontrol ability in this BCA strain. The functional roles of many genes identified as contributing to antagonism and in vivo biocontrol activity require further study. SIGNIFICANCE AND IMPACT OF THIS STUDY Genes contributing to antifungal activity and biocontrol performance of P. fluorescens were identified and highlighted by Tn mutagenesis, which will give insight to improve the biocontrol performance of this BCA.
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Affiliation(s)
- S Dutta
- Division of Biotechnology, Chonbuk National University, Iksan-si, Jeollabuk-do, Republic of Korea
| | - S-M Yu
- Freshwater Bioresources Utilization Division, Nakdonggang National Institute of Biological Resources, Sangju-si, Gyeongsangbuk-do, Republic of Korea
| | - S C Jeong
- Freshwater Bioresources Utilization Division, Nakdonggang National Institute of Biological Resources, Sangju-si, Gyeongsangbuk-do, Republic of Korea
| | - Y H Lee
- Division of Biotechnology, Chonbuk National University, Iksan-si, Jeollabuk-do, Republic of Korea.,Advanced Institute of Environment and Bioscience, Plant Medical Research Center, and Institute of Bio-industry, Chonbuk National University, Ikansi-si, Jeollabuk-do, Republic of Korea
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Potentiation of Aminoglycoside Lethality by C 4-Dicarboxylates Requires RpoN in Antibiotic-Tolerant Pseudomonas aeruginosa. Antimicrob Agents Chemother 2019; 63:AAC.01313-19. [PMID: 31383655 DOI: 10.1128/aac.01313-19] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2019] [Accepted: 07/29/2019] [Indexed: 01/26/2023] Open
Abstract
Antibiotic tolerance contributes to the inability of standard antimicrobial therapies to clear the chronic Pseudomonas aeruginosa lung infections that often afflict patients with cystic fibrosis (CF). Metabolic potentiation of bactericidal antibiotics with carbon sources has emerged as a promising strategy to resensitize tolerant bacteria to antibiotic killing. Fumarate (FUM), a C4-dicarboxylate, has been recently shown to resensitize tolerant P. aeruginosa to killing by tobramycin (TOB), an aminoglycoside antibiotic, when used in combination (TOB+FUM). Fumarate and other C4-dicarboxylates are taken up intracellularly by transporters regulated by the alternative sigma factor RpoN. Once in the cell, FUM is metabolized, leading to enhanced electron transport chain activity, regeneration of the proton motive force, and increased TOB uptake. In this work, we demonstrate that a ΔrpoN mutant displays impaired FUM uptake and, consequently, nonsusceptibility to TOB+FUM treatment. RpoN was also found to be essential for susceptibility to other aminoglycoside and C4-dicarboxylate combinations. Importantly, RpoN loss-of-function mutations have been documented to evolve in the CF lung, and these loss-of-function alleles can also result in TOB+FUM nonsusceptibility. In a mixed-genotype population of wild-type and ΔrpoN cells, TOB+FUM specifically killed cells with RpoN function and spared the cells that lacked RpoN function. Unlike C4-dicarboylates, both d-glucose and l-arginine were able to potentiate TOB killing of ΔrpoN stationary-phase cells. Our findings raise the question of whether TOB+FUM will be a suitable treatment option in the future for CF patients infected with P. aeruginosa isolates that lack RpoN function.
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Singh VS, Tripathi P, Pandey P, Singh DN, Dubey BK, Singh C, Singh SP, Pandey R, Tripathi AK. Dicarboxylate Transporters of Azospirillum brasilense Sp7 Play an Important Role in the Colonization of Finger Millet ( Eleusine coracana) Roots. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2019; 32:828-840. [PMID: 30688544 DOI: 10.1094/mpmi-12-18-0344-r] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Azospirillum brasilense is a plant growth-promoting bacterium that colonizes the roots of a large number of plants, including C3 and C4 grasses. Malate has been used as a preferred source of carbon for the enrichment and isolation Azospirillum spp., but the genes involved in their transport and utilization are not yet characterized. In this study, we investigated the role of the two types of dicarboxylate transporters (DctP and DctA) of A. brasilense in their ability to colonize and promote growth of the roots of a C4 grass. We found that DctP protein was distinctly upregulated in A. brasilense grown with malate as sole carbon source. Inactivation of dctP in A. brasilense led to a drastic reduction in its ability to grow on dicarboxylates and form cell aggregates. Inactivation of dctA, however, showed a marginal reduction in growth and flocculation. The growth and nitrogen fixation of a dctP and dctA double mutant of A. brasilense were severely compromised. We have shown here that DctPQM and DctA transporters play a major and a minor role in the transport of C4-dicarboxylates in A. brasilense, respectively. Studies on inoculation of the seedlings of a C4 grass, Eleusine corcana, with A. brasilense and its dicarboxylate transport mutants revealed that dicarboxylate transporters are required by A. brasilense for an efficient colonization of plant roots and their growth.
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Affiliation(s)
- Vijay Shankar Singh
- 1 School of Biotechnology, Institute of Science, Banaras Hindu University, Varanasi-221005, India
| | - Prajna Tripathi
- 1 School of Biotechnology, Institute of Science, Banaras Hindu University, Varanasi-221005, India
| | - Parul Pandey
- 1 School of Biotechnology, Institute of Science, Banaras Hindu University, Varanasi-221005, India
| | - Durgesh Narain Singh
- 2 Laboratory of Synthetic Biology, Division of Biotechnology, CSIR-Central Institute of Medicinal and Aromatic Plants, Lucknow-226015, India
| | - Basant Kumar Dubey
- 2 Laboratory of Synthetic Biology, Division of Biotechnology, CSIR-Central Institute of Medicinal and Aromatic Plants, Lucknow-226015, India
| | - Chhaya Singh
- 1 School of Biotechnology, Institute of Science, Banaras Hindu University, Varanasi-221005, India
| | - Surendra Pratap Singh
- 3 Department of Botany, Dayanand Anglo-Vedic (PG) College (Affiliated to CSJM University, Kanpur), Civil Lines, Kanpur-208001, India
| | - Rachana Pandey
- 4 Dr D Y Patil Biotechnology and Bioinformatics Institute, Dr D. Y. Patil Vidyapeeth Pune-411033, India
| | - Anil Kumar Tripathi
- 1 School of Biotechnology, Institute of Science, Banaras Hindu University, Varanasi-221005, India
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Bhagirath AY, Li Y, Patidar R, Yerex K, Ma X, Kumar A, Duan K. Two Component Regulatory Systems and Antibiotic Resistance in Gram-Negative Pathogens. Int J Mol Sci 2019; 20:E1781. [PMID: 30974906 PMCID: PMC6480566 DOI: 10.3390/ijms20071781] [Citation(s) in RCA: 83] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2019] [Revised: 04/05/2019] [Accepted: 04/08/2019] [Indexed: 12/17/2022] Open
Abstract
Gram-negative pathogens such as Klebsiella pneumoniae, Acinetobacter baumannii, and Pseudomonas aeruginosa are the leading cause of nosocomial infections throughout the world. One commonality shared among these pathogens is their ubiquitous presence, robust host-colonization and most importantly, resistance to antibiotics. A significant number of two-component systems (TCSs) exist in these pathogens, which are involved in regulation of gene expression in response to environmental signals such as antibiotic exposure. While the development of antimicrobial resistance is a complex phenomenon, it has been shown that TCSs are involved in sensing antibiotics and regulating genes associated with antibiotic resistance. In this review, we aim to interpret current knowledge about the signaling mechanisms of TCSs in these three pathogenic bacteria. We further attempt to answer questions about the role of TCSs in antimicrobial resistance. We will also briefly discuss how specific two-component systems present in K. pneumoniae, A. baumannii, and P. aeruginosa may serve as potential therapeutic targets.
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Affiliation(s)
- Anjali Y Bhagirath
- Department of Oral Biology, Rady Faculty of Health Sciences, University of Manitoba, 780 Bannatyne Ave, Winnipeg, MB R3E 0J9, Canada.
| | - Yanqi Li
- Department of Oral Biology, Rady Faculty of Health Sciences, University of Manitoba, 780 Bannatyne Ave, Winnipeg, MB R3E 0J9, Canada.
| | - Rakesh Patidar
- Department of Microbiology, Faculty of Sciences, University of Manitoba, Winnipeg, MB R3E 0J9, Canada.
| | - Katherine Yerex
- Department of Oral Biology, Rady Faculty of Health Sciences, University of Manitoba, 780 Bannatyne Ave, Winnipeg, MB R3E 0J9, Canada.
| | - Xiaoxue Ma
- Department of Oral Biology, Rady Faculty of Health Sciences, University of Manitoba, 780 Bannatyne Ave, Winnipeg, MB R3E 0J9, Canada.
| | - Ayush Kumar
- Department of Microbiology, Faculty of Sciences, University of Manitoba, Winnipeg, MB R3E 0J9, Canada.
| | - Kangmin Duan
- Department of Oral Biology, Rady Faculty of Health Sciences, University of Manitoba, 780 Bannatyne Ave, Winnipeg, MB R3E 0J9, Canada.
- Department of Medical Microbiology & Infectious Diseases, Rady Faculty of Health Sciences, University of Manitoba, 780 Bannatyne Ave, Winnipeg, MB R3E 0J9, Canada.
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Raneri M, Pinatel E, Peano C, Rampioni G, Leoni L, Bianconi I, Jousson O, Dalmasio C, Ferrante P, Briani F. Pseudomonas aeruginosa mutants defective in glucose uptake have pleiotropic phenotype and altered virulence in non-mammal infection models. Sci Rep 2018; 8:16912. [PMID: 30442901 PMCID: PMC6237876 DOI: 10.1038/s41598-018-35087-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2018] [Accepted: 10/30/2018] [Indexed: 01/09/2023] Open
Abstract
Pseudomonas spp. are endowed with a complex pathway for glucose uptake that relies on multiple transporters. In this work we report the construction and characterization of Pseudomonas aeruginosa single and multiple mutants with unmarked deletions of genes encoding outer membrane (OM) and inner membrane (IM) proteins involved in glucose uptake. We found that a triple ΔgltKGF ΔgntP ΔkguT mutant lacking all known IM transporters (named GUN for Glucose Uptake Null) is unable to grow on glucose as unique carbon source. More than 500 genes controlling both metabolic functions and virulence traits show differential expression in GUN relative to the parental strain. Consistent with transcriptomic data, the GUN mutant displays a pleiotropic phenotype. Notably, the genome-wide transcriptional profile and most phenotypic traits differ between the GUN mutant and the wild type strain irrespective of the presence of glucose, suggesting that the investigated genes may have additional roles besides glucose transport. Finally, mutants carrying single or multiple deletions in the glucose uptake genes showed attenuated virulence relative to the wild type strain in Galleria mellonella, but not in Caenorhabditis elegans infection model, supporting the notion that metabolic functions may deeply impact P. aeruginosa adaptation to specific environments found inside the host.
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Affiliation(s)
- Matteo Raneri
- Dipartimento di Bioscienze, Università degli Studi di Milano, Milano, Italy
| | - Eva Pinatel
- Istituto di Tecnologie Biomediche-CNR, Segrate, Italy
| | - Clelia Peano
- Istituto di Tecnologie Biomediche-CNR, Segrate, Italy
- Istituto Clinico Humanitas-CNR, Rozzano, Italy
| | - Giordano Rampioni
- Dipartimento di Scienze, Università degli Studi Roma Tre, Roma, Italy
| | - Livia Leoni
- Dipartimento di Scienze, Università degli Studi Roma Tre, Roma, Italy
| | - Irene Bianconi
- Centre for Integrative Biology, Università degli Studi di Trento, Trento, Italy
| | - Olivier Jousson
- Centre for Integrative Biology, Università degli Studi di Trento, Trento, Italy
| | - Chiara Dalmasio
- Dipartimento di Bioscienze, Università degli Studi di Milano, Milano, Italy
| | - Palma Ferrante
- Dipartimento di Bioscienze, Università degli Studi di Milano, Milano, Italy
| | - Federica Briani
- Dipartimento di Bioscienze, Università degli Studi di Milano, Milano, Italy.
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Gill EE, Chan LS, Winsor GL, Dobson N, Lo R, Ho Sui SJ, Dhillon BK, Taylor PK, Shrestha R, Spencer C, Hancock REW, Unrau PJ, Brinkman FSL. High-throughput detection of RNA processing in bacteria. BMC Genomics 2018; 19:223. [PMID: 29587634 PMCID: PMC5870498 DOI: 10.1186/s12864-018-4538-8] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2017] [Accepted: 02/12/2018] [Indexed: 01/19/2023] Open
Abstract
Background Understanding the RNA processing of an organism’s transcriptome is an essential but challenging step in understanding its biology. Here we investigate with unprecedented detail the transcriptome of Pseudomonas aeruginosa PAO1, a medically important and innately multi-drug resistant bacterium. We systematically mapped RNA cleavage and dephosphorylation sites that result in 5′-monophosphate terminated RNA (pRNA) using monophosphate RNA-Seq (pRNA-Seq). Transcriptional start sites (TSS) were also mapped using differential RNA-Seq (dRNA-Seq) and both datasets were compared to conventional RNA-Seq performed in a variety of growth conditions. Results The pRNA-Seq library revealed known tRNA, rRNA and transfer-messenger RNA (tmRNA) processing sites, together with previously uncharacterized RNA cleavage events that were found disproportionately near the 5′ ends of transcripts associated with basic bacterial functions such as oxidative phosphorylation and purine metabolism. The majority (97%) of the processed mRNAs were cleaved at precise codon positions within defined sequence motifs indicative of distinct endonucleolytic activities. The most abundant of these motifs corresponded closely to an E. coli RNase E site previously established in vitro. Using the dRNA-Seq library, we performed an operon analysis and predicted 3159 potential TSS. A correlation analysis uncovered 105 antiparallel pairs of TSS that were separated by 18 bp from each other and were centered on single palindromic TAT(A/T)ATA motifs (likely − 10 promoter elements), suggesting that, consistent with previous in vitro experimentation, these sites can initiate transcription bi-directionally and may thus provide a novel form of transcriptional regulation. TSS and RNA-Seq analysis allowed us to confirm expression of small non-coding RNAs (ncRNAs), many of which are differentially expressed in swarming and biofilm formation conditions. Conclusions This study uses pRNA-Seq, a method that provides a genome-wide survey of RNA processing, to study the bacterium Pseudomonas aeruginosa and discover extensive transcript processing not previously appreciated. We have also gained novel insight into RNA maturation and turnover as well as a potential novel form of transcription regulation. NOTE: All sequence data has been submitted to the NCBI sequence read archive. Accession numbers are as follows: [NCBI sequence read archive: SRX156386, SRX157659, SRX157660, SRX157661, SRX157683 and SRX158075]. The sequence data is viewable using Jbrowse on www.pseudomonas.com. Electronic supplementary material The online version of this article (10.1186/s12864-018-4538-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Erin E Gill
- Department of Molecular Biology and Biochemistry, Simon Fraser University, 8888 University Drive, Burnaby, BC, V5A 1S6, Canada
| | - Luisa S Chan
- Department of Molecular Biology and Biochemistry, Simon Fraser University, 8888 University Drive, Burnaby, BC, V5A 1S6, Canada
| | - Geoffrey L Winsor
- Department of Molecular Biology and Biochemistry, Simon Fraser University, 8888 University Drive, Burnaby, BC, V5A 1S6, Canada
| | - Neil Dobson
- Department of Molecular Biology and Biochemistry, Simon Fraser University, 8888 University Drive, Burnaby, BC, V5A 1S6, Canada
| | - Raymond Lo
- Department of Molecular Biology and Biochemistry, Simon Fraser University, 8888 University Drive, Burnaby, BC, V5A 1S6, Canada
| | - Shannan J Ho Sui
- Department of Molecular Biology and Biochemistry, Simon Fraser University, 8888 University Drive, Burnaby, BC, V5A 1S6, Canada
| | - Bhavjinder K Dhillon
- Department of Molecular Biology and Biochemistry, Simon Fraser University, 8888 University Drive, Burnaby, BC, V5A 1S6, Canada
| | - Patrick K Taylor
- Centre for Microbial Diseases and Immunity Research, University of British Columbia, Vancouver, BC, Canada
| | - Raunak Shrestha
- Department of Molecular Biology and Biochemistry, Simon Fraser University, 8888 University Drive, Burnaby, BC, V5A 1S6, Canada
| | - Cory Spencer
- Department of Molecular Biology and Biochemistry, Simon Fraser University, 8888 University Drive, Burnaby, BC, V5A 1S6, Canada
| | - Robert E W Hancock
- Centre for Microbial Diseases and Immunity Research, University of British Columbia, Vancouver, BC, Canada
| | - Peter J Unrau
- Department of Molecular Biology and Biochemistry, Simon Fraser University, 8888 University Drive, Burnaby, BC, V5A 1S6, Canada.
| | - Fiona S L Brinkman
- Department of Molecular Biology and Biochemistry, Simon Fraser University, 8888 University Drive, Burnaby, BC, V5A 1S6, Canada.
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Gellatly SL, Bains M, Breidenstein EBM, Strehmel J, Reffuveille F, Taylor PK, Yeung ATY, Overhage J, Hancock REW. Novel roles for two-component regulatory systems in cytotoxicity and virulence-related properties in Pseudomonas aeruginosa. AIMS Microbiol 2018; 4:173-191. [PMID: 31294209 PMCID: PMC6605022 DOI: 10.3934/microbiol.2018.1.173] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2017] [Accepted: 02/26/2018] [Indexed: 11/18/2022] Open
Abstract
The rapid adaptation of the opportunistic bacterial pathogen Pseudomonas aeruginosa to various growth modes and environmental conditions is controlled in part through diverse two-component regulatory systems. Some of these systems are well studied, but the majority are poorly characterized, even though it is likely that several of these systems contribute to virulence. Here, we screened all available strain PA14 mutants in 50 sensor kinases, 50 response regulators and 5 hybrid sensor/regulators, for contributions to cytotoxicity against cultured human bronchial epithelial cells, as assessed by the release of cytosolic lactate dehydrogenase. This enabled the identification of 8 response regulators and 3 sensor kinases that caused substantial decreases in cytotoxicity, and 5 response regulators and 8 sensor kinases that significantly increased cytotoxicity by 15-58% or more. These regulators were additionally involved in motility, adherence, type 3 secretion, production of cytotoxins, and the development of biofilms. Here we investigated in more detail the roles of FleSR, PilSR and WspR. Not all cognate pairs contributed to cytotoxicity (e.g. PhoPQ, PilSR) in the same way and some differences could be detected between the same mutants in PAO1 and PA14 strain backgrounds (e.g. FleSR, PhoPQ). This study highlights the potential importance of these regulators and their downstream targets on pathogenesis and demonstrates that cytotoxicity can be regulated by several systems and that their contributions are partly dependent on strain background.
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Affiliation(s)
- Shaan L Gellatly
- Centre for Microbial Diseases and Immunity Research, Department of Microbiology & Immunology, University of British Columbia, Vancouver, BC, Canada
| | - Manjeet Bains
- Centre for Microbial Diseases and Immunity Research, Department of Microbiology & Immunology, University of British Columbia, Vancouver, BC, Canada
| | - Elena B M Breidenstein
- Centre for Microbial Diseases and Immunity Research, Department of Microbiology & Immunology, University of British Columbia, Vancouver, BC, Canada
| | - Janine Strehmel
- Microbiology of Natural and Technical Interfaces Department, Institute of Functional Interfaces (IFG), Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
| | - Fany Reffuveille
- Centre for Microbial Diseases and Immunity Research, Department of Microbiology & Immunology, University of British Columbia, Vancouver, BC, Canada
| | - Patrick K Taylor
- Centre for Microbial Diseases and Immunity Research, Department of Microbiology & Immunology, University of British Columbia, Vancouver, BC, Canada
| | - Amy T Y Yeung
- Centre for Microbial Diseases and Immunity Research, Department of Microbiology & Immunology, University of British Columbia, Vancouver, BC, Canada
| | - Joerg Overhage
- Microbiology of Natural and Technical Interfaces Department, Institute of Functional Interfaces (IFG), Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
| | - Robert E W Hancock
- Centre for Microbial Diseases and Immunity Research, Department of Microbiology & Immunology, University of British Columbia, Vancouver, BC, Canada
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Francis VI, Stevenson EC, Porter SL. Two-component systems required for virulence in Pseudomonas aeruginosa. FEMS Microbiol Lett 2018; 364:3828290. [PMID: 28510688 PMCID: PMC5812489 DOI: 10.1093/femsle/fnx104] [Citation(s) in RCA: 108] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2017] [Accepted: 05/15/2017] [Indexed: 11/13/2022] Open
Abstract
Pseudomonas aeruginosa is a versatile opportunistic pathogen capable of infecting a broad range of hosts, in addition to thriving in a broad range of environmental conditions outside of hosts. With this versatility comes the need to tightly regulate its genome to optimise its gene expression and behaviour to the prevailing conditions. Two-component systems (TCSs) comprising sensor kinases and response regulators play a major role in this regulation. This minireview discusses the growing number of TCSs that have been implicated in the virulence of P. aeruginosa, with a special focus on the emerging theme of multikinase networks, which are networks comprising multiple sensor kinases working together, sensing and integrating multiple signals to decide upon the best response. The networks covered in depth regulate processes such as the switch between acute and chronic virulence (GacS network), the Cup fimbriae (Roc network and Rcs/Pvr network), the aminoarabinose modification of lipopolysaccharide (a network involving the PhoQP and PmrBA TCSs), twitching motility and virulence (a network formed from the Chp chemosensory pathway and the FimS/AlgR TCS), and biofilm formation (Wsp chemosensory pathway). In addition, we highlight the important interfaces between these systems and secondary messenger signals such as cAMP and c-di-GMP.
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Affiliation(s)
- Vanessa I Francis
- Biosciences, Geoffrey Pope Building, College of Life and Environmental Sciences, University of Exeter, Exeter EX 4QD, UK
| | - Emma C Stevenson
- Biosciences, Geoffrey Pope Building, College of Life and Environmental Sciences, University of Exeter, Exeter EX 4QD, UK
| | - Steven L Porter
- Biosciences, Geoffrey Pope Building, College of Life and Environmental Sciences, University of Exeter, Exeter EX 4QD, UK
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Li G, Lu CD. Molecular characterization and regulation of operons for asparagine and aspartate uptake and utilization in Pseudomonas aeruginosa. MICROBIOLOGY-SGM 2018; 164:205-216. [PMID: 29293081 DOI: 10.1099/mic.0.000594] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Pseudomonas aeruginosa can utilize proteogenic amino acids as the sole source of carbon and nitrogen. In particular, utilization of l-Asp and l-Asn is insensitive to carbon catabolite repression as strong growth remains in the mutants devoid of the essential CbrAB activators of most catabolic genes. Transcriptome analysis was conducted to identify genes for the catabolism, uptake and regulation of these two amino acids. Gene inactivation and growth phenotype analysis established two asparaginases AsnA and AsnB for the degradation of l-Asn to l-Asp, whereas only AnsB is required for the deamidation of d-Asn to d-Asp. While d-Asp is a dead-end product, conversion of l-Asp to fumarate is catalysed by an aspartase AspA as further evidenced by enzyme kinetics. The results of measuring promoter-lacZ expression in vivo and mobility shift assays in vitro demonstrated that asnR and aspR encode two transcriptional regulators in response to l-Asn and l-Asp, respectively, for the induction of the ansPA operon and the aspA gene. Exogenous l-Glu also caused induction of the aspA gene, most likely due to its conversion to l-Asp by the aspartate transaminase AspC. Expression of several transporters were found inducible by l-Asn and/or l-Asp, including AatJQMP for acid amino acids, DctA and DctPQM for C4-dicarboxylates, and PA5530 for C5-dicarboxylates. In summary, a complete pathway and regulation for l-Asn and l-Asp catabolism was established in this study. Cross induction of three transport systems for dicarboxylic acids may provide a physiological explanation for the insensitivity of l-Asn and l-Asp utilization to carbon catabolite repression.
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Affiliation(s)
- Guoqing Li
- Department of Biomedical and Nutritional Sciences, University of Massachusetts at Lowell, Lowell, MA 01854, USA.,Institute of Medical Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, PR China
| | - Chung-Dar Lu
- Department of Biomedical and Nutritional Sciences, University of Massachusetts at Lowell, Lowell, MA 01854, USA
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An Antipersister Strategy for Treatment of Chronic Pseudomonas aeruginosa Infections. Antimicrob Agents Chemother 2017; 61:AAC.00987-17. [PMID: 28923873 DOI: 10.1128/aac.00987-17] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2017] [Accepted: 09/08/2017] [Indexed: 12/21/2022] Open
Abstract
Bacterial persisters are a quasidormant subpopulation of cells that are tolerant to antibiotic treatment. The combination of the aminoglycoside tobramycin with fumarate as an antibacterial potentiator utilizes an antipersister strategy that is aimed at reducing recurrent Pseudomonas aeruginosa infections by enhancing the killing of P. aeruginosa persisters. Stationary-phase cultures of P. aeruginosa were used to generate persister cells. A range of tobramycin concentrations was tested with a range of metabolite concentrations to determine the potentiation effect of the metabolite under a variety of conditions, including a range of pH values and in the presence of azithromycin or cystic fibrosis (CF) patient sputum. In addition, 96-well dish biofilm and colony biofilm assays were performed, and the cytotoxicity of the tobramycin-fumarate combination was determined utilizing a lactate dehydrogenase (LDH) assay. Enhanced killing of up to 6 orders of magnitude of P. aeruginosa persisters over a range of CF isolates, including mucoid and nonmucoid strains, was observed for the tobramycin-fumarate combination compared to killing with tobramycin alone. Furthermore, significant fumarate-mediated potentiation was seen in the presence of azithromycin or CF patient sputum. Fumarate also reduced the cytotoxicity of tobramycin-treated P. aeruginosa to human epithelial airway cells. Finally, in mucoid and nonmucoid CF isolates, complete eradication of P. aeruginosa biofilm was observed in the colony biofilm assay due to fumarate potentiation. These data suggest that a combination of tobramycin with fumarate as an antibacterial potentiator may be an attractive therapeutic for eliminating recurrent P. aeruginosa infections in CF patients through the eradication of bacterial persisters.
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Starke R, Bastida F, Abadía J, García C, Nicolás E, Jehmlich N. Ecological and functional adaptations to water management in a semiarid agroecosystem: a soil metaproteomics approach. Sci Rep 2017; 7:10221. [PMID: 28860535 PMCID: PMC5579227 DOI: 10.1038/s41598-017-09973-w] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2017] [Accepted: 08/02/2017] [Indexed: 01/14/2023] Open
Abstract
Climate change models point to a decrease in water availability in semiarid areas that would compromise the maintenance of sustainable agriculture. Here, we used a grapefruit agroecosystem model to evaluate the responses of the active soil microbial community – as a microbial subset directly involved in soil functionality- undergoing strategies to cope with the low water availability in south-east Spain. For this purpose, we tested the impacts of: (i) water quality: transfer-water from a river (TW) or reclaimed-water from a wastewater-treatment plant (RW); and (ii) water quantity: continuous optimal amount of water or reduced irrigation (RDI) in the temporal frame when the crop is less sensitive; and their interactions. Metaproteomics revealed that the phylogenetic diversity of the active community and its functional diversity were lowered in soils with RW. RDI lowered soil respiration and functional diversity while the phylogenetic diversity remained constant. The reestablishment of full irrigation after RDI led to a recovery of soil respiration that was accompanied by an enhanced abundance of resilient bacterial populations. Bacterial populations displayed molecular mechanisms against water stress that have been conserved evolutionarily in plants. Protein-based studies shed light on ecological and functional mechanisms that govern the adaptive responses of soil microbial communities to climate-change friendly water management.
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Affiliation(s)
- Robert Starke
- Helmholtz-Centre for Environmental Research - UFZ, Department of Molecular Systems Biology, Permoserstrasse 15, 04318, Leipzig, Germany
| | - Felipe Bastida
- Centro de Edafología y Biología Aplicada del Segura. Spanish Research Council (CEBAS-CSIC). Campus Universitario de Espinardo, CP 30100 PO Box 164, Murcia, Spain.
| | - Joaquín Abadía
- Centro de Edafología y Biología Aplicada del Segura. Spanish Research Council (CEBAS-CSIC). Campus Universitario de Espinardo, CP 30100 PO Box 164, Murcia, Spain
| | - Carlos García
- Centro de Edafología y Biología Aplicada del Segura. Spanish Research Council (CEBAS-CSIC). Campus Universitario de Espinardo, CP 30100 PO Box 164, Murcia, Spain
| | - Emilio Nicolás
- Centro de Edafología y Biología Aplicada del Segura. Spanish Research Council (CEBAS-CSIC). Campus Universitario de Espinardo, CP 30100 PO Box 164, Murcia, Spain
| | - Nico Jehmlich
- Helmholtz-Centre for Environmental Research - UFZ, Department of Molecular Systems Biology, Permoserstrasse 15, 04318, Leipzig, Germany
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Tomada S, Sonego P, Moretto M, Engelen K, Pertot I, Perazzolli M, Puopolo G. Dual RNA-Seq of Lysobacter capsici
AZ78 - Phytophthora infestans
interaction shows the implementation of attack strategies by the bacterium and unsuccessful oomycete defense responses. Environ Microbiol 2017; 19:4113-4125. [DOI: 10.1111/1462-2920.13861] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2017] [Revised: 07/14/2017] [Accepted: 07/17/2017] [Indexed: 01/03/2023]
Affiliation(s)
- Selena Tomada
- Department of Sustainable Agro-Ecosystems and Bioresources, Research and Innovation Centre; Fondazione Edmund Mach (FEM); San Michele all'Adige Italy
- Agricultural Science and Biotechnology, Department of Agricultural, Food, Environmental and Animal Sciences; University of Udine; Udine Italy
| | - Paolo Sonego
- Department of Computational Biology, Research and Innovation Centre; Fondazione Edmund Mach (FEM); San Michele all'Adige Italy
| | - Marco Moretto
- Department of Computational Biology, Research and Innovation Centre; Fondazione Edmund Mach (FEM); San Michele all'Adige Italy
| | - Kristof Engelen
- Department of Computational Biology, Research and Innovation Centre; Fondazione Edmund Mach (FEM); San Michele all'Adige Italy
| | - Ilaria Pertot
- Department of Sustainable Agro-Ecosystems and Bioresources, Research and Innovation Centre; Fondazione Edmund Mach (FEM); San Michele all'Adige Italy
- Center Agriculture Food Environment; University of Trento; San Michele all'Adige Italy
| | - Michele Perazzolli
- Department of Sustainable Agro-Ecosystems and Bioresources, Research and Innovation Centre; Fondazione Edmund Mach (FEM); San Michele all'Adige Italy
| | - Gerardo Puopolo
- Department of Sustainable Agro-Ecosystems and Bioresources, Research and Innovation Centre; Fondazione Edmund Mach (FEM); San Michele all'Adige Italy
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Liu Y, Gokhale CS, Rainey PB, Zhang XX. Unravelling the complexity and redundancy of carbon catabolic repression in Pseudomonas fluorescens SBW25. Mol Microbiol 2017; 105:589-605. [PMID: 28557013 DOI: 10.1111/mmi.13720] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/24/2017] [Indexed: 12/11/2022]
Abstract
The two-component system CbrAB is the principal regulator for cellular metabolic balance in Pseudomonas fluorescens SBW25 and is necessary for growth on many substrates including xylose. To understand the regulatory linkage between CbrAB and genes for xylose utilization (xut), we performed transposon mutagenesis of ΔcbrB to select for Xut+ suppressors. This led to identification of crc and hfq. Subsequent genetic and biochemical analysis showed that Crc and Hfq are key mediators of succinate-provoked carbon catabolite repression (CCR). Specifically, Crc/Hfq sequentially bind to mRNAs of both the transcriptional activator and structural genes involved in xylose catabolism. However, in the absence of succinate, repression is relieved through competitive binding by two ncRNAs, CrcY and CrcZ, whose expression is activated by CbrAB. These findings provoke a model for CCR in which it is assumed that crc and hfq are functionally complementary, whereas crcY and crcZ are genetically redundant. Inactivation of either crcY or crcZ produced no effects on bacterial fitness in laboratory media, however, results of mathematical modelling predict that the co-existence of crcY and crcZ requires separate functional identity. Finally, we provide empirical evidence that CCR is advantageous in nutrient-complex environments where preferred carbon sources are present at high concentrations but fluctuate in their availability.
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Affiliation(s)
- Yunhao Liu
- Institute of Natural and Mathematical Sciences, Massey University at Albany, Auckland, 0745, New Zealand.,New Zealand Institute for Advanced Study, Massey University at Albany, Auckland, 0745, New Zealand
| | - Chaitanya S Gokhale
- New Zealand Institute for Advanced Study, Massey University at Albany, Auckland, 0745, New Zealand.,Department of Evolutionary Theory, Max Planck Institute for Evolutionary Biology, Plön 24306, Germany
| | - Paul B Rainey
- New Zealand Institute for Advanced Study, Massey University at Albany, Auckland, 0745, New Zealand.,Department of Microbial Population Biology, Max Planck Institute for Evolutionary Biology, Plön, 24306, Germany.,Ecole Supérieure de Physique et de Chimie Industrielles de la Ville de Paris (ESPCI ParisTech), CNRS UMR 8231, PSL Research University, 75231 Paris Cedex 05, France
| | - Xue-Xian Zhang
- Institute of Natural and Mathematical Sciences, Massey University at Albany, Auckland, 0745, New Zealand
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Overexpression of a C 4-dicarboxylate transporter is the key for rerouting citric acid to C 4-dicarboxylic acid production in Aspergillus carbonarius. Microb Cell Fact 2017; 16:43. [PMID: 28288640 PMCID: PMC5348913 DOI: 10.1186/s12934-017-0660-6] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Accepted: 03/08/2017] [Indexed: 11/24/2022] Open
Abstract
Background C4-dicarboxylic acids, including malic acid, fumaric acid and succinic acid, are valuable organic acids that can be produced and secreted by a number of microorganisms. Previous studies on organic acid production by Aspergillus carbonarius, which is capable of producing high amounts of citric acid from varieties carbon sources, have revealed its potential as a fungal cell factory. Earlier attempts to reroute citric acid production into C4-dicarboxylic acids have been with limited success. Results In this study, a glucose oxidase deficient strain of A. carbonarius was used as the parental strain to overexpress a native C4-dicarboxylate transporter and the gene frd encoding fumarate reductase from Trypanosoma brucei individually and in combination. Impacts of the introduced genetic modifications on organic acid production were investigated in a defined medium and in a hydrolysate of wheat straw containing high concentrations of glucose and xylose. In the defined medium, overexpression of the C4-dicarboxylate transporter alone and in combination with the frd gene significantly increased the production of C4-dicarboxylic acids and reduced the accumulation of citric acid, whereas expression of the frd gene alone did not result in any significant change of organic acid production profile. In the wheat straw hydrolysate after 9 days of cultivation, similar results were obtained as in the defined medium. High amounts of malic acid and succinic acid were produced by the same strains. Conclusions This study demonstrates that the key to change the citric acid production into production of C4-dicarboxylic acids in A. carbonarius is the C4-dicarboxylate transporter. Furthermore it shows that the C4-dicarboxylic acid production by A. carbonarius can be further increased via metabolic engineering and also shows the potential of A. carbonarius to utilize lignocellulosic biomass as substrates for C4-dicarboxylic acid production.
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Wösten MMSM, van de Lest CHA, van Dijk L, van Putten JPM. Function and Regulation of the C4-Dicarboxylate Transporters in Campylobacter jejuni. Front Microbiol 2017; 8:174. [PMID: 28223978 PMCID: PMC5293742 DOI: 10.3389/fmicb.2017.00174] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2016] [Accepted: 01/24/2017] [Indexed: 01/13/2023] Open
Abstract
C4-dicarboxylates are important molecules for the human pathogen C.jejuni, as they are used as carbon and electron acceptor molecules, as sugars cannot be utilized by this microaerophilic organism. Based on the genome analysis, C. jejuni may possess five different C4–dicarboxylate transporters: DctA, DcuA, DcuB, and two homologs of DcuC. Here, we investigated the regulation and function of various C4–dicarboxylate transporters in C. jejuni. Transcription of the dctA and dcuC homologs is constitutive, while dcuA and dcuB are both directly regulated by the two-component RacR/RacS system in response to limited oxygen availability and the presence of nitrate. The DctA transporter is the only C4-dicarboxylate transporter to allow C. jejuni to grow on C4-carbon sources such as aspartate, fumarate, and succinate at high oxygen levels (10% O2) and is indispensable for the uptake of succinate from the medium under these conditions. Both DcuA and DcuB can sequester aspartate from the medium under low-oxygen conditions (0.3% O2). However, under these conditions, DcuB is the only transporter to secrete succinate to the environment. Under low-oxygen conditions, nitrate prevents the secretion of succinate to the environment and was able to overrule the phenotype of the C4-transporter mutants, indicating that the activity of the aspartate–fumarate–succinate pathway in C. jejuni is strongly reduced by the addition of nitrate in the medium.
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Affiliation(s)
- Marc M S M Wösten
- Department of Infectious Diseases and Immunology, Utrecht University Utrecht, Netherlands
| | - Chris H A van de Lest
- Department of Biochemistry and Cell Biology, Utrecht University Utrecht, Netherlands
| | - Linda van Dijk
- Department of Infectious Diseases and Immunology, Utrecht University Utrecht, Netherlands
| | - Jos P M van Putten
- Department of Infectious Diseases and Immunology, Utrecht University Utrecht, Netherlands
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Zhang Y, Jiang T, Sheng B, Long Y, Gao C, Ma C, Xu P. Coexistence of two d-lactate-utilizing systems in Pseudomonas putida KT2440. ENVIRONMENTAL MICROBIOLOGY REPORTS 2016; 8:699-707. [PMID: 27264531 DOI: 10.1111/1758-2229.12429] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2016] [Revised: 05/13/2016] [Accepted: 05/24/2016] [Indexed: 06/05/2023]
Abstract
It is advantageous for rhizosphere-dwelling microorganisms to utilize organic acids such as lactate. Pseudomonas putida KT2440 is one of the most widely studied rhizosphere-dwelling model organisms. The P. putida KT2440 genome contains an NAD-dependent d-lactate dehydrogenase encoding gene, but mutation of this gene does not play a role in d-lactate utilization. Instead, it was found that d-lactate utilization in P. putida KT2440 proceeds via a multidomain NAD-independent d-lactate dehydrogenase with a C-terminal domain containing several Fe-S cluster-binding motifs (Fe-S d-iLDH) and glycolate oxidase, which is widely distributed in various microorganisms. Both Fe-S d-iLDH and glycolate oxidase were identified to be membrane-bound proteins. Neither Fe-S d-iLDH nor glycolate oxidase is constitutively expressed but both of them can be induced by either enantiomer of lactate in P. putida KT2440. This study shows a case in which an environmental microbe contains two types of enzymes specific for d-lactate utilization.
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Affiliation(s)
- Yingxin Zhang
- State Key Laboratory of Microbial Technology and School of Life Sciences, Shandong University, Jinan, 250100, People's Republic of China
| | - Tianyi Jiang
- State Key Laboratory of Microbial Technology and School of Life Sciences, Shandong University, Jinan, 250100, People's Republic of China
- School of Municipal and Environmental Engineering, Shandong Jianzhu University, Jinan, 250101, People's Republic of China
| | - Binbin Sheng
- State Key Laboratory of Microbial Technology and School of Life Sciences, Shandong University, Jinan, 250100, People's Republic of China
| | - Yangdanyu Long
- State Key Laboratory of Microbial Technology and School of Life Sciences, Shandong University, Jinan, 250100, People's Republic of China
| | - Chao Gao
- State Key Laboratory of Microbial Technology and School of Life Sciences, Shandong University, Jinan, 250100, People's Republic of China
| | - Cuiqing Ma
- State Key Laboratory of Microbial Technology and School of Life Sciences, Shandong University, Jinan, 250100, People's Republic of China
| | - Ping Xu
- State Key Laboratory of Microbial Metabolism and School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, People's Republic of China
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Iyer B, Rajput MS, Jog R, Joshi E, Bharwad K, Rajkumar S. Organic acid mediated repression of sugar utilization in rhizobia. Microbiol Res 2016; 192:211-220. [PMID: 27664739 DOI: 10.1016/j.micres.2016.07.006] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2016] [Revised: 07/20/2016] [Accepted: 07/25/2016] [Indexed: 01/17/2023]
Abstract
Rhizobia are a class of symbiotic diazotrophic bacteria which utilize C4 acids in preference to sugars and the sugar utilization is repressed as long as C4 acids are present. This can be manifested as a diauxie when rhizobia are grown in the presence of a sugar and a C4 acid together. Succinate, a C4 acid is known to repress utilization of sugars, sugar alcohols, hydrocarbons, etc by a mechanism termed as Succinate Mediated Catabolite Repression (SMCR). Mechanism of catabolite repression determines the hierarchy of carbon source utilization in bacteria. Though the mechanism of catabolite repression has been well studied in model organisms like E. coli, B. subtilis and Pseudomonas sp., mechanism of SMCR in rhizobia has not been well elucidated. C4 acid uptake is important for effective symbioses while mutation in the sugar transport and utilization genes does not affect symbioses. Deletion of hpr and sma0113 resulted in the partial relief of SMCR of utilization of galactosides like lactose, raffinose and maltose in the presence of succinate. However, no such regulators governing SMCR of glucoside utilization have been identified till date. Though rhizobia can utilize multitude of sugars, high affinity transporters for many sugars are yet to be identified. Identifying high affinity sugar transporters and studying the mechanism of catabolite repression in rhizobia is important to understand the level of regulation of SMCR and the key regulators involved in SMCR.
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Affiliation(s)
- Bhagya Iyer
- Institute of Science, Nirma University, Ahmedabad, Gujarat, India
| | | | - Rahul Jog
- Institute of Science, Nirma University, Ahmedabad, Gujarat, India; Environmental Molecular Biology Laboratory, Division of Biosphere, Faculty of Environmental Earth Science, Hokkaido University, Sapporo, Hokkaido, Japan
| | - Ekta Joshi
- Institute of Science, Nirma University, Ahmedabad, Gujarat, India
| | - Krishna Bharwad
- Institute of Science, Nirma University, Ahmedabad, Gujarat, India
| | - Shalini Rajkumar
- Institute of Science, Nirma University, Ahmedabad, Gujarat, India.
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Xiao M, Lai Y, Sun J, Chen G, Yan A. Transcriptional Regulation of the Outer Membrane Porin Gene ompW Reveals its Physiological Role during the Transition from the Aerobic to the Anaerobic Lifestyle of Escherichia coli. Front Microbiol 2016; 7:799. [PMID: 27303386 PMCID: PMC4886647 DOI: 10.3389/fmicb.2016.00799] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2016] [Accepted: 05/11/2016] [Indexed: 11/13/2022] Open
Abstract
Understanding bacterial physiology relies on elucidating the regulatory mechanisms and cellular functions of those differentially expressed genes in response to environmental changes. A widespread Gram-negative bacterial outer membrane protein OmpW has been implicated in the adaptation to stresses in various species. It is recently found to be present in the regulon of the global anaerobic transcription factor FNR and ArcA in Escherichia coli. However, little is known about the physiological implications of this regulatory disposition. In this study, we demonstrate that transcription of ompW is indeed mediated by a series of global regulators involved in the anaerobiosis of E. coli. We show that FNR can both activate and repress the expression of ompW through its direct binding to two distinctive sites, -81.5 and -126.5 bp respectively, on ompW promoter. ArcA also participates in repression of ompW under anaerobic condition, but in an FNR dependent manner. Additionally, ompW is also subject to the regulation by CRP and NarL which senses the availability and types of carbon sources and respiration electron acceptors in the environment respectively, implying a role of OmpW in the carbon and energy metabolism of E. coli during its anaerobic adaptation. Molecular docking reveals that OmpW can bind fumarate, an alternative electron acceptor in anaerobic respiration, with sufficient affinity. Moreover, supplement of fumarate or succinate which belongs to the C4-dicarboxylates family of metabolite, to E. coli culture rescues OmpW-mediated colicin S4 killing. Taken together, we propose that OmpW is involved in anaerobic carbon and energy metabolism to mediate the transition from aerobic to anaerobic lifestyle in E. coli.
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Affiliation(s)
- Minfeng Xiao
- School of Biological Sciences, The University of Hong Kong Hong Kong, China
| | - Yong Lai
- School of Biological Sciences, The University of Hong Kong Hong Kong, China
| | - Jian Sun
- Department of Chemistry, The University of Hong Kong Hong Kong, China
| | - Guanhua Chen
- Department of Chemistry, The University of Hong Kong Hong Kong, China
| | - Aixin Yan
- School of Biological Sciences, The University of Hong Kong Hong Kong, China
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GcsR, a TyrR-Like Enhancer-Binding Protein, Regulates Expression of the Glycine Cleavage System in Pseudomonas aeruginosa PAO1. mSphere 2016; 1:mSphere00020-16. [PMID: 27303730 PMCID: PMC4894688 DOI: 10.1128/msphere.00020-16] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2016] [Accepted: 04/06/2016] [Indexed: 02/01/2023] Open
Abstract
Glycine is required for various cellular functions, including cell wall synthesis, protein synthesis, and the biosynthesis of several important metabolites. Regulating levels of glycine metabolism allows P. aeruginosa to maintain the metabolic flux of glycine through several pathways, including the metabolism of glycine to produce other amino acids, entry into the trichloroacetic acid cycle, and the production of virulence factors such as hydrogen cyanide. In this study, we characterized GcsR, a transcriptional regulator that activates the expression of genes involved in P. aeruginosa PAO1 glycine metabolism. Our work reveals that GcsR is the founding member of a novel class of TyrR-like EBPs that likely regulate glycine metabolism in Pseudomonadales. Glycine serves as a major source of single carbon units for biochemical reactions within bacterial cells. Utilization of glycine is tightly regulated and revolves around a key group of proteins known as the glycine cleavage system (GCS). Our lab previously identified the transcriptional regulator GcsR (PA2449) as being required for catabolism of glycine in the opportunistic pathogen Pseudomonas aeruginosa PAO1. In an effort to clarify and have an overall better understanding of the role of GcsR in glycine metabolism, a combination of transcriptome sequencing and electrophoretic mobility shift assays was used to identify target genes of this transcriptional regulator. It was found that GcsR binds to an 18-bp consensus sequence (TGTAACG-N4-CGTTCCG) upstream of the gcs2 operon, consisting of the gcvH2, gcvP2, glyA2, sdaA, and gcvT2 genes. The proteins encoded by these genes, namely, the GCS (GcvH2-GcvP2-GcvT2), serine hydroxymethyltransferase (GlyA2), and serine dehydratase (SdaA), form a metabolic pathway for the conversion of glycine into pyruvate, which can enter the central metabolism. GcsR activates transcription of the gcs2 operon in response to glycine. Interestingly, GcsR belongs to a family of transcriptional regulators known as TyrR-like enhancer-binding proteins (EBPs). Until this study, TyrR-like EBPs were only known to function in regulating aromatic amino acid metabolism. GcsR is the founding member of a new class of TyrR-like EBPs that function in the regulation of glycine metabolism. Indeed, homologs of GcsR and its target genes are present in almost all sequenced genomes of the Pseudomonadales order, suggesting that this genetic regulatory mechanism is a common theme for pseudomonads. IMPORTANCE Glycine is required for various cellular functions, including cell wall synthesis, protein synthesis, and the biosynthesis of several important metabolites. Regulating levels of glycine metabolism allows P. aeruginosa to maintain the metabolic flux of glycine through several pathways, including the metabolism of glycine to produce other amino acids, entry into the trichloroacetic acid cycle, and the production of virulence factors such as hydrogen cyanide. In this study, we characterized GcsR, a transcriptional regulator that activates the expression of genes involved in P. aeruginosa PAO1 glycine metabolism. Our work reveals that GcsR is the founding member of a novel class of TyrR-like EBPs that likely regulate glycine metabolism in Pseudomonadales.
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50
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Unden G, Wörner S, Monzel C. Cooperation of Secondary Transporters and Sensor Kinases in Transmembrane Signalling: The DctA/DcuS and DcuB/DcuS Sensor Complexes of Escherichia coli. Adv Microb Physiol 2016; 68:139-67. [PMID: 27134023 DOI: 10.1016/bs.ampbs.2016.02.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Many membrane-bound sensor kinases require accessory proteins for function. The review describes functional control of membrane-bound sensors by transporters. The C4-dicarboxylate sensor kinase DcuS requires the aerobic or anaerobic C4-dicarboxylate transporters DctA or DcuB, respectively, for function and forms DctA/DcuS or DcuB/DcuS sensor complexes. Free DcuS is in the permanent (ligand independent) ON state. The DctA/DcuS and DcuB/DcuS complexes, on the other hand, control expression in response to C4-dicarboxylates. In DctA/DcuS, helix 8b of DctA and the PASC domain of DcuS are involved in interaction. The stimulus is perceived by the extracytoplasmic sensor domain (PASP) of DcuS. The signal is transmitted across the membrane by a piston-type movement of TM2 of DcuS which appears to be pulled (by analogy to the homologous citrate sensor CitA) by compaction of PASP after C4-dicarboxylate binding. In the cytoplasm, the signal is perceived by the PASC domain of DcuS. PASC inhibits together with DctA the kinase domain of DcuS which is released after C4-dicarboxylate binding. DcuS exhibits two modes for regulating expression of target genes. At higher C4-dicarboxylate levels, DcuS is part of the DctA/DcuS complex and in the C4-dicarboxylate-responsive form which stimulates expression of target genes in response to the concentration of the C4-dicarboxylates (catabolic use of C4-dicarboxylates, mode I regulation). At limiting C4-dicarboxylate concentrations (≤0.05mM), expression of DctA drops and free DcuS appears. Free DcuS is in the permanent ON state (mode II regulation) and stimulates low level (C4-dicarboxylate independent) DctA synthesis for DctA/DcuS complex formation and anabolic C4-dicarboxylate uptake.
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Affiliation(s)
- G Unden
- Institute for Microbiology and Wine Research, University of Mainz, Mainz, Germany.
| | - S Wörner
- Institute for Microbiology and Wine Research, University of Mainz, Mainz, Germany
| | - C Monzel
- Institute for Microbiology and Wine Research, University of Mainz, Mainz, Germany
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