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Fan J, Mo X, Zhang H, Xu L, Yin J, Wan F. Identification of the organic peroxide scavenging system of Yersinia pseudotuberculosis and its regulation by OxyR. Appl Environ Microbiol 2024; 90:e0146824. [PMID: 39264182 PMCID: PMC11497825 DOI: 10.1128/aem.01468-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2024] [Accepted: 08/19/2024] [Indexed: 09/13/2024] Open
Abstract
Oxidative stress caused by reactive oxygen species (ROS) is inevitable for all aerobic microorganisms as ROS are the byproducts of aerobic respiration. For gut pathogens, ROS are an integrated part of colonization resistance which protects the host against bacteria invasion. Alkyl hydroperoxide reductase (AhpR) and organic hydroperoxide resistance (Ohr) proteins are considered as the main enzymes responsible for the degradation of organic peroxides (OPs) in most bacteria. To elucidate how enteric pathogen Yersinia pseudotuberculosis YPIII deals with oxidative stress induced by OPs, we performed transcriptomic analysis and identified the OP scavenging system, which is composed of glutathione peroxidase (Gpx), thiol peroxidase (Tpx), and AhpR. Gpx serves as the main scavenger of OPs, and Tpx assists in the degradation of OPs. Transcriptional factor OxyR regulates Gpx expression, suggesting that OxyR is the regulator mediating the cellular response to OPs. Although AhpR has little influence on OP degradation, its deletion would greatly impair the scavenging ability of OPs in the absence of gpx or tpx. In addition, we found that catalase KatG and KatE are responsive to OPs but do not participate in the removal of OPs.IMPORTANCEIn bacteria, oxidative stress caused by ROS is a continuously occurring cellular response and requires multiple genes to participate in this process. The elimination of OPs is mainly dependent on AhpR and Ohr protein. Here, we carried out transcriptomic analysis to search for enzymes responsible for the removal of organic peroxides in Yersinia pseudotuberculosis. We found that Gpx was the primary OP scavenger in bacteria, which was positively regulated by the oxidative stress regulator OxyR. The OP scavenging system in Y. pseudotuberculosis was composedof Gpx, Tpx, and AhpR. OxyR is the critical global regulator mediating gene expression involved in OPs and H2O2 stress. These findings suggest that Y. pseudotuberculosis has a unique defense system in response to oxidative stress.
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Affiliation(s)
- Junfeng Fan
- School of Laboratory Medicine and Biotechnology, Hangzhou Medical College, Hangzhou, China
- Key Laboratory of Biomarkers and In Vitro Diagnosis Translation of Zhejiang Province, Hangzhou, China
| | - Xiaofen Mo
- School of Laboratory Medicine and Biotechnology, Hangzhou Medical College, Hangzhou, China
- Key Laboratory of Biomarkers and In Vitro Diagnosis Translation of Zhejiang Province, Hangzhou, China
| | - Hui Zhang
- School of Laboratory Medicine and Biotechnology, Hangzhou Medical College, Hangzhou, China
- Key Laboratory of Biomarkers and In Vitro Diagnosis Translation of Zhejiang Province, Hangzhou, China
| | - Linna Xu
- School of Laboratory Medicine and Biotechnology, Hangzhou Medical College, Hangzhou, China
| | - Jianhua Yin
- Institute of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, China
| | - Fen Wan
- School of Laboratory Medicine and Biotechnology, Hangzhou Medical College, Hangzhou, China
- Key Laboratory of Biomarkers and In Vitro Diagnosis Translation of Zhejiang Province, Hangzhou, China
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2
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Xie P, Xu Y, Tang J, Wu S, Gao H. Multifaceted regulation of siderophore synthesis by multiple regulatory systems in Shewanella oneidensis. Commun Biol 2024; 7:498. [PMID: 38664541 PMCID: PMC11045786 DOI: 10.1038/s42003-024-06193-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2024] [Accepted: 04/15/2024] [Indexed: 04/28/2024] Open
Abstract
Siderophore-dependent iron uptake is a mechanism by which microorganisms scavenge and utilize iron for their survival, growth, and many specialized activities, such as pathogenicity. The siderophore biosynthetic system PubABC in Shewanella can synthesize a series of distinct siderophores, yet how it is regulated in response to iron availability remains largely unexplored. Here, by whole genome screening we identify TCS components histidine kinase (HK) BarA and response regulator (RR) SsoR as positive regulators of siderophore biosynthesis. While BarA partners with UvrY to mediate expression of pubABC post-transcriptionally via the Csr regulatory cascade, SsoR is an atypical orphan RR of the OmpR/PhoB subfamily that activates transcription in a phosphorylation-independent manner. By combining structural analysis and molecular dynamics simulations, we observe conformational changes in OmpR/PhoB-like RRs that illustrate the impact of phosphorylation on dynamic properties, and that SsoR is locked in the 'phosphorylated' state found in phosphorylation-dependent counterparts of the same subfamily. Furthermore, we show that iron homeostasis global regulator Fur, in addition to mediating transcription of its own regulon, acts as the sensor of iron starvation to increase SsoR production when needed. Overall, this study delineates an intricate, multi-tiered transcriptional and post-transcriptional regulatory network that governs siderophore biosynthesis.
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Affiliation(s)
- Peilu Xie
- Institute of Microbiology and College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, 310058, China
| | - Yuanyou Xu
- Institute of Microbiology and College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, 310058, China
| | - Jiaxin Tang
- Institute of Microbiology and College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, 310058, China
| | - Shihua Wu
- Institute of Microbiology and College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, 310058, China.
| | - Haichun Gao
- Institute of Microbiology and College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, 310058, China.
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Liu X, Li J, Zhang Z, He Y, Wang M, Zhao Y, Lin S, Liu T, Liao Y, Zhang N, Yuan K, Ling Y, Liu Z, Chen X, Chen Z, Chen R, Wang X, Gu B. Acetylation of xenogeneic silencer H-NS regulates biofilm development through the nitrogen homeostasis regulator in Shewanella. Nucleic Acids Res 2024; 52:2886-2903. [PMID: 38142446 PMCID: PMC11014242 DOI: 10.1093/nar/gkad1219] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Revised: 12/08/2023] [Accepted: 12/12/2023] [Indexed: 12/26/2023] Open
Abstract
Adjusting intracellular metabolic pathways and adopting suitable live state such as biofilms, are crucial for bacteria to survive environmental changes. Although substantial progress has been made in understanding how the histone-like nucleoid-structuring (H-NS) protein modulates the expression of the genes involved in biofilm formation, the precise modification that the H-NS protein undergoes to alter its DNA binding activity is still largely uncharacterized. This study revealed that acetylation of H-NS at Lys19 inhibits biofilm development in Shewanella oneidensis MR-1 by downregulating the expression of glutamine synthetase, a critical enzyme in glutamine synthesis. We further found that nitrogen starvation, a likely condition in biofilm development, induces deacetylation of H-NS and the trimerization of nitrogen assimilation regulator GlnB. The acetylated H-NS strain exhibits significantly lower cellular glutamine concentration, emphasizing the requirement of H-NS deacetylation in Shewanella biofilm development. Moreover, we discovered in vivo that the activation of glutamine biosynthesis pathway and the concurrent suppression of the arginine synthesis pathway during both pellicle and attached biofilms development, further suggesting the importance of fine tune nitrogen assimilation by H-NS acetylation in Shewanella. In summary, posttranslational modification of H-NS endows Shewanella with the ability to respond to environmental needs by adjusting the intracellular metabolism pathways.
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Affiliation(s)
- Xiaoxiao Liu
- Laboratory Medicine, Guangdong Provincial People's Hospital (Guangdong Academy of Medical Sciences), Southern Medical University, Guangzhou 510000, China
- Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, Innovation Academy of South China Sea Ecology and Environmental Engineering, South China Sea Institute of Oceanology, Chinese Academy of Sciences, No. 1119, Haibin Road, Nansha District, Guangzhou 511458, China
- Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), No. 1119, Haibin Road, Nansha District, Guangzhou 511458, China
| | - Jun Li
- Laboratory Medicine, Guangdong Provincial People's Hospital (Guangdong Academy of Medical Sciences), Southern Medical University, Guangzhou 510000, China
| | - Zhixuan Zhang
- Laboratory Medicine, Guangdong Provincial People's Hospital (Guangdong Academy of Medical Sciences), Southern Medical University, Guangzhou 510000, China
- School of Medicine, South China University of Technology, Guangzhou, Guangdong 510080, China
| | - Yizhou He
- Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, Innovation Academy of South China Sea Ecology and Environmental Engineering, South China Sea Institute of Oceanology, Chinese Academy of Sciences, No. 1119, Haibin Road, Nansha District, Guangzhou 511458, China
| | - Mingfang Wang
- Laboratory Medicine, Guangdong Provincial People's Hospital (Guangdong Academy of Medical Sciences), Southern Medical University, Guangzhou 510000, China
| | - Yunhu Zhao
- Laboratory Medicine, Guangdong Provincial People's Hospital (Guangdong Academy of Medical Sciences), Southern Medical University, Guangzhou 510000, China
| | - Shituan Lin
- Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, Innovation Academy of South China Sea Ecology and Environmental Engineering, South China Sea Institute of Oceanology, Chinese Academy of Sciences, No. 1119, Haibin Road, Nansha District, Guangzhou 511458, China
- Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), No. 1119, Haibin Road, Nansha District, Guangzhou 511458, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Tianlang Liu
- Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, Innovation Academy of South China Sea Ecology and Environmental Engineering, South China Sea Institute of Oceanology, Chinese Academy of Sciences, No. 1119, Haibin Road, Nansha District, Guangzhou 511458, China
- Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), No. 1119, Haibin Road, Nansha District, Guangzhou 511458, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yiwen Liao
- Laboratory Medicine, Guangdong Provincial People's Hospital (Guangdong Academy of Medical Sciences), Southern Medical University, Guangzhou 510000, China
| | - Ni Zhang
- Laboratory Medicine, Guangdong Provincial People's Hospital (Guangdong Academy of Medical Sciences), Southern Medical University, Guangzhou 510000, China
| | - Kaixuan Yuan
- Laboratory Medicine, Guangdong Provincial People's Hospital (Guangdong Academy of Medical Sciences), Southern Medical University, Guangzhou 510000, China
| | - Yong Ling
- Laboratory Medicine, Guangdong Provincial People's Hospital (Guangdong Academy of Medical Sciences), Southern Medical University, Guangzhou 510000, China
| | - Ziyao Liu
- Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, Innovation Academy of South China Sea Ecology and Environmental Engineering, South China Sea Institute of Oceanology, Chinese Academy of Sciences, No. 1119, Haibin Road, Nansha District, Guangzhou 511458, China
- Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), No. 1119, Haibin Road, Nansha District, Guangzhou 511458, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xiaozhong Chen
- Laboratory Medicine, Guangdong Provincial People's Hospital (Guangdong Academy of Medical Sciences), Southern Medical University, Guangzhou 510000, China
| | - Zhe Chen
- Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, Innovation Academy of South China Sea Ecology and Environmental Engineering, South China Sea Institute of Oceanology, Chinese Academy of Sciences, No. 1119, Haibin Road, Nansha District, Guangzhou 511458, China
- Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), No. 1119, Haibin Road, Nansha District, Guangzhou 511458, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Ran Chen
- Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, Innovation Academy of South China Sea Ecology and Environmental Engineering, South China Sea Institute of Oceanology, Chinese Academy of Sciences, No. 1119, Haibin Road, Nansha District, Guangzhou 511458, China
- Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), No. 1119, Haibin Road, Nansha District, Guangzhou 511458, China
| | - Xiaoxue Wang
- Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, Innovation Academy of South China Sea Ecology and Environmental Engineering, South China Sea Institute of Oceanology, Chinese Academy of Sciences, No. 1119, Haibin Road, Nansha District, Guangzhou 511458, China
- Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), No. 1119, Haibin Road, Nansha District, Guangzhou 511458, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Bing Gu
- Laboratory Medicine, Guangdong Provincial People's Hospital (Guangdong Academy of Medical Sciences), Southern Medical University, Guangzhou 510000, China
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Ren Y, Liu R, Zheng Y, Wang H, Meng Q, Zhu T, Yin J, Cao X, Yu Z. Biosynthetic mechanism of the yellow pigments in the marine bacterium Pseudoalteromonas sp. strain T1lg65. Appl Environ Microbiol 2024; 90:e0177923. [PMID: 38193673 PMCID: PMC10880671 DOI: 10.1128/aem.01779-23] [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: 10/06/2023] [Accepted: 11/28/2023] [Indexed: 01/10/2024] Open
Abstract
The Pseudoalteromonas genus marine bacteria have attracted increasing interest because of their abilities to produce bioactive metabolites. The pigmented Pseudoalteromonas group encodes more secondary metabolite biosynthetic gene clusters (BGCs) than the non-pigmented group. Here, we report a yellow pigmented bacterium Pseudoalteromonas sp. strain T1lg65, which was isolated from a mangrove forest sediment. We showed that the yellow pigments of T1lg65 belong to the group of lipopeptide alterochromides. Further genetic analyses of the alterochromide BGC revealed that the yellow pigments are biosynthesized by aryl-polyene synthases and nonribosomal peptide synthases. Within the gene cluster, altA encodes a tyrosine ammonia acid lyase, which catalyzes synthesis of the precursor 4-hydroxycinnamic acid (4-HCA) from tyrosine in the alterochromide biosynthetic pathway. In addition, altN, encoding a putative flavin-dependent halogenase, was proven to be responsible for the bromination of alterochromides based on gene deletion, molecular docking, and site mutagenesis analyses. In summary, the biosynthetic pathway, precursor synthesis, and bromination mechanism of the lipopeptide alterochromides were studied in-depth. Our results expand the knowledge on biosynthesis of Pseudoalteromonas pigments and could promote the development of active pigments in the future.IMPORTANCEThe marine bacteria Pseudoalteromonas spp. are important biological resources because they are producers of bioactive natural products, including antibiotics, pigments, enzymes, and antimicrobial peptides. One group of the microbial pigments, alterochromides, holds a great value for their novel lipopeptide structures and antimicrobial activities. Previous studies were limited to the structural characterization of alterochromides and genome mining for the alterochromide biosynthesis. This work focused on the biosynthetic mechanism for alterochromide production, especially revealing functions of two key genes within the gene cluster for the alterochromide biosynthesis. On the one hand, our study provides a target for metabolic engineering of the alterochromide biosynthesis; on the other hand, the 4-HCA synthase AltA and brominase AltN show potential in the biocatalyst industry.
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Affiliation(s)
- Yixuan Ren
- College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, China
| | - Ruoyu Liu
- College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, China
| | - Yifan Zheng
- College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, China
| | - Hang Wang
- College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, China
| | - Qiu Meng
- College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, China
| | - Tingheng Zhu
- College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, China
| | - Jianhua Yin
- College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, China
| | - Xueqiang Cao
- College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, China
| | - Zhiliang Yu
- College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, China
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5
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Zhang J, Li F, Liu D, Liu Q, Song H. Engineering extracellular electron transfer pathways of electroactive microorganisms by synthetic biology for energy and chemicals production. Chem Soc Rev 2024; 53:1375-1446. [PMID: 38117181 DOI: 10.1039/d3cs00537b] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2023]
Abstract
The excessive consumption of fossil fuels causes massive emission of CO2, leading to climate deterioration and environmental pollution. The development of substitutes and sustainable energy sources to replace fossil fuels has become a worldwide priority. Bio-electrochemical systems (BESs), employing redox reactions of electroactive microorganisms (EAMs) on electrodes to achieve a meritorious combination of biocatalysis and electrocatalysis, provide a green and sustainable alternative approach for bioremediation, CO2 fixation, and energy and chemicals production. EAMs, including exoelectrogens and electrotrophs, perform extracellular electron transfer (EET) (i.e., outward and inward EET), respectively, to exchange energy with the environment, whose rate determines the efficiency and performance of BESs. Therefore, we review the synthetic biology strategies developed in the last decade for engineering EAMs to enhance the EET rate in cell-electrode interfaces for facilitating the production of electricity energy and value-added chemicals, which include (1) progress in genetic manipulation and editing tools to achieve the efficient regulation of gene expression, knockout, and knockdown of EAMs; (2) synthetic biological engineering strategies to enhance the outward EET of exoelectrogens to anodes for electricity power production and anodic electro-fermentation (AEF) for chemicals production, including (i) broadening and strengthening substrate utilization, (ii) increasing the intracellular releasable reducing equivalents, (iii) optimizing c-type cytochrome (c-Cyts) expression and maturation, (iv) enhancing conductive nanowire biosynthesis and modification, (v) promoting electron shuttle biosynthesis, secretion, and immobilization, (vi) engineering global regulators to promote EET rate, (vii) facilitating biofilm formation, and (viii) constructing cell-material hybrids; (3) the mechanisms of inward EET, CO2 fixation pathway, and engineering strategies for improving the inward EET of electrotrophic cells for CO2 reduction and chemical production, including (i) programming metabolic pathways of electrotrophs, (ii) rewiring bioelectrical circuits for enhancing inward EET, and (iii) constructing microbial (photo)electrosynthesis by cell-material hybridization; (4) perspectives on future challenges and opportunities for engineering EET to develop highly efficient BESs for sustainable energy and chemical production. We expect that this review will provide a theoretical basis for the future development of BESs in energy harvesting, CO2 fixation, and chemical synthesis.
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Affiliation(s)
- Junqi Zhang
- Frontier Science Center for Synthetic Biology (Ministry of Education), Key Laboratory of Systems Bioengineering, and School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, China.
| | - Feng Li
- Frontier Science Center for Synthetic Biology (Ministry of Education), Key Laboratory of Systems Bioengineering, and School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, China.
| | - Dingyuan Liu
- Frontier Science Center for Synthetic Biology (Ministry of Education), Key Laboratory of Systems Bioengineering, and School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, China.
| | - Qijing Liu
- Frontier Science Center for Synthetic Biology (Ministry of Education), Key Laboratory of Systems Bioengineering, and School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, China.
| | - Hao Song
- Frontier Science Center for Synthetic Biology (Ministry of Education), Key Laboratory of Systems Bioengineering, and School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, China.
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6
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Sun W, Xu Y, Liang Y, Yu Q, Gao H. A novel bacterial sulfite dehydrogenase that requires three c-type cytochromes for electron transfer. Appl Environ Microbiol 2023; 89:e0110823. [PMID: 37732808 PMCID: PMC10617556 DOI: 10.1128/aem.01108-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2023] [Accepted: 07/27/2023] [Indexed: 09/22/2023] Open
Abstract
c-type Cytochromes (c-Cyts), primarily as electron carriers and oxidoreductases, play a key role in energy transduction processes in virtually all living organisms. Many bacteria, such as Shewanella oneidensis, are particularly rich in c-Cyts, supporting respiratory versatility not seen in eukaryotes. Unfortunately, a large number of c-Cyts are underexplored, and their biological functions remain unknown. In this study, we identify SorCABD of S. oneidensis as a novel sulfite dehydrogenase (SDH), which catalyzes the oxidation of sulfite to sulfate. In addition to catalytic subunit SorA, this enzymatic complex includes three c-Cyt subunits, which all together carry out electron transfer. The electrons extracted from sulfite oxidation are ultimately delivered to oxygen, leading to oxygen reduction, a process relying on terminal oxidase cyt cbb3. Genomic analysis suggests that the homologs of this SDH are present in a small number of bacterial genera, Shewanella and Vibrio in particular. Because these bacteria are generally capable of reducing sulfite under anaerobic conditions, the co-existence of a sulfite oxidation system implies that they may play especially important roles in the transformation of sulfur species in natural environments.Importancec-type Cytochromes (c-Cyts) endow bacteria with high flexibility in their oxidative/respiratory systems, allowing them to extracellularly transform diverse inorganic and organic compounds for survival and growth. However, a large portion of the bacterial c-Cyts remain functionally unknown. Here, we identify three c-Cyts that work together as essential electron transfer partners for the catalytic subunit of a novel SDH in sulfite oxidation in Shewanella oneidensis. This characteristic makes S. oneidensis the first organism known to be capable of oxidizing and reducing sulfite. The findings suggest that Shewanella, along with a small number of other aquatic bacteria, would serve as a particular driving force in the biogeochemical sulfur cycle in nature.
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Affiliation(s)
- Weining Sun
- Key Laboratory of Aging and Cancer Biology of Zhejiang Province, Department of Immunology and Pathogen Biology, School of Basic Medical Sciences, Hangzhou Normal University, Hangzhou, China
- Institute of Microbiology and College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, China
| | - Yuanyou Xu
- Institute of Microbiology and College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, China
| | - Yawen Liang
- Institute of Microbiology and College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, China
| | - Qingzi Yu
- Institute of Microbiology and College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, China
| | - Haichun Gao
- Institute of Microbiology and College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, China
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7
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Han S, Guo K, Wang W, Tao YJ, Gao H. Bacterial TANGO2 homologs are heme-trafficking proteins that facilitate biosynthesis of cytochromes c. mBio 2023; 14:e0132023. [PMID: 37462360 PMCID: PMC10470608 DOI: 10.1128/mbio.01320-23] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2023] [Accepted: 06/05/2023] [Indexed: 09/02/2023] Open
Abstract
Heme, an essential molecule for virtually all living organisms, acts primarily as a cofactor in a large number of proteins. However, how heme is mobilized from the site of synthesis to the locations where hemoproteins are assembled remains largely unknown in cells, especially bacterial ones. In this study, with Shewanella oneidensis as the model, we identified HtpA (SO0126) as a heme-trafficking protein and homolog of TANGO2 proteins found in eukaryotes. We showed that HtpA homologs are widely distributed in all domains of living organisms and have undergone parallel evolution. In its absence, the cytochrome (cyt) c content and catalase activity decreased significantly. We further showed that both HtpA and representative TANGO2 proteins bind heme with 1:1 stoichiometry and a relatively low dissociation constant. Protein interaction analyses substantiated that HtpA directly interacts with the cytochrome c maturation system. Our findings shed light on cross-membrane transport of heme in bacteria and extend the understanding of TANGO2 proteins. IMPORTANCE The intracellular trafficking of heme, an essential cofactor for hemoproteins, remains underexplored even in eukaryotes, let alone bacteria. Here we developed a high-throughput method by which HtpA, a homolog of eukaryotic TANGO2 proteins, was identified to be a heme-binding protein that enhances cytochrome c biosynthesis and catalase activity in Shewanella oneidensis. HtpA interacts with the cytochrome c biosynthesis system directly, supporting that this protein, like TANGO2, functions in intracellular heme trafficking. HtpA homologs are widely distributed, but a large majority of them were found to be non-exchangeable, likely a result of parallel evolution. By substantiating the heme-trafficking nature of HtpA and its eukaryotic homologs, our findings provide general insight into the heme-trafficking process and highlight the functional conservation along evolution in all living organisms.
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Affiliation(s)
- Sirui Han
- Institute of Microbiology, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, China
| | - Kailun Guo
- Institute of Microbiology, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, China
| | - Wei Wang
- Institute of Microbiology, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, China
| | - Yizhi J. Tao
- Department of BioSciences, Rice University, Houston, Texas, USA
| | - Haichun Gao
- Institute of Microbiology, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, China
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8
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Li F, Tang R, Zhang B, Qiao C, Yu H, Liu Q, Zhang J, Shi L, Song H. Systematic Full-Cycle Engineering Microbial Biofilms to Boost Electricity Production in Shewanella oneidensis. RESEARCH (WASHINGTON, D.C.) 2023; 6:0081. [PMID: 36939407 PMCID: PMC10017123 DOI: 10.34133/research.0081] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Accepted: 01/31/2023] [Indexed: 02/04/2023]
Abstract
Electroactive biofilm plays a crucial rule in the electron transfer efficiency of microbial electrochemical systems (MES). However, the low ability to form biofilm and the low conductivity of the formed biofilm substantially limit the extracellular electron transfer rate of microbial cells to the electrode surfaces in MES. To promote biofilm formation and enhance biofilm conductivity, we develop synthetic biology approach to systematically engineer Shewanella oneidensis, a model exoelectrogen, via modular manipulation of the full-cycle different stages of biofilm formation, namely, from initial contact, cell adhesion, and biofilm growth stable maturity to cell dispersion. Consequently, the maximum output power density of the engineered biofilm reaches 3.62 ± 0.06 W m-2, 39.3-fold higher than that of the wild-type strain of S. oneidensis, which, to the best our knowledge, is the highest output power density that has ever been reported for the biofilms of the genetically engineered Shewanella strains.
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Affiliation(s)
- Feng Li
- Frontiers Science Center for Synthetic Biology (Ministry of Education), and Key Laboratory of Systems Bioengineering,
Tianjin University, Tianjin 300072, China
- Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), School of Chemical Engineering and Technology,
Tianjin University, Tianjin 300072, China
| | - Rui Tang
- Frontiers Science Center for Synthetic Biology (Ministry of Education), and Key Laboratory of Systems Bioengineering,
Tianjin University, Tianjin 300072, China
- Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), School of Chemical Engineering and Technology,
Tianjin University, Tianjin 300072, China
| | - Baocai Zhang
- Frontiers Science Center for Synthetic Biology (Ministry of Education), and Key Laboratory of Systems Bioengineering,
Tianjin University, Tianjin 300072, China
- Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), School of Chemical Engineering and Technology,
Tianjin University, Tianjin 300072, China
| | - Chunxiao Qiao
- Frontiers Science Center for Synthetic Biology (Ministry of Education), and Key Laboratory of Systems Bioengineering,
Tianjin University, Tianjin 300072, China
- Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), School of Chemical Engineering and Technology,
Tianjin University, Tianjin 300072, China
| | - Huan Yu
- Frontiers Science Center for Synthetic Biology (Ministry of Education), and Key Laboratory of Systems Bioengineering,
Tianjin University, Tianjin 300072, China
- Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), School of Chemical Engineering and Technology,
Tianjin University, Tianjin 300072, China
| | - Qijing Liu
- Frontiers Science Center for Synthetic Biology (Ministry of Education), and Key Laboratory of Systems Bioengineering,
Tianjin University, Tianjin 300072, China
- Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), School of Chemical Engineering and Technology,
Tianjin University, Tianjin 300072, China
| | - Junqi Zhang
- Frontiers Science Center for Synthetic Biology (Ministry of Education), and Key Laboratory of Systems Bioengineering,
Tianjin University, Tianjin 300072, China
- Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), School of Chemical Engineering and Technology,
Tianjin University, Tianjin 300072, China
| | - Liang Shi
- Department of Biological Sciences and Technology, School of Environmental Studies,
China University of Geoscience in Wuhan, Wuhan, Hubei 430074, China
| | - Hao Song
- Frontiers Science Center for Synthetic Biology (Ministry of Education), and Key Laboratory of Systems Bioengineering,
Tianjin University, Tianjin 300072, China
- Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), School of Chemical Engineering and Technology,
Tianjin University, Tianjin 300072, China
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9
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Wu Y, Zhu X, Wang X, Lin Z, Reinfelder JR, Li F, Liu T. A New Electron Shuttling Pathway Mediated by Lipophilic Phenoxazine via the Interaction with Periplasmic and Inner Membrane Proteins of Shewanella oneidensis MR-1. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:2636-2646. [PMID: 36652548 DOI: 10.1021/acs.est.2c07862] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Although it has been established that electron mediators substantially promote extracellular electron transfer (EET), electron shuttling pathways are not fully understood. Here, a new electron shuttling pathway was found in the EET process by Shewanella oneidensis MR-1 with resazurin, a lipophilic electron mediator. With resazurin, the genes encoding outer-membrane cytochromes (mtrCBA and omcA) were downregulated. Although cytochrome deletion substantially reduced biocurrent generation to 1-12% of that of wild-type (WT) cells, the presence of resazurin restored biocurrent generation to 168 μA·cm-2 (ΔmtrA/omcA/mtrC), nearly equivalent to that of WT cells (194 μA·cm-2), indicating that resazurin-mediated electron transfer was not dependent on the Mtr pathway. Biocurrent generation by resazurin was much lower in ΔcymA and ΔmtrA/omcA/mtrC/fccA/cctA mutants (4 and 6 μA·cm-2) than in WT cells, indicating a key role of FccA, CctA, and CymA in this process. The effectiveness of resazurin in EET of Mtr cytochrome mutants is also supported by cyclic voltammetry, resazurin reduction kinetics, and in situ c-type cytochrome spectroscopy results. The findings demonstrated that low molecular weight, lipophilic electron acceptors, such as phenoxazine and phenazine, may facilitate electron transfer directly from periplasmic and inner membrane proteins, thus providing new insight into the roles of exogenous electron mediators in electron shuttling in natural and engineered biogeochemical systems.
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Affiliation(s)
- Yundang Wu
- National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China, Guangdong Key Laboratory of Integrated Agro-environmental Pollution Control and Management, Institute of Eco-environmental and Soil Sciences, Guangdong Academy of Sciences, Guangzhou 510650, China
| | - Xiao Zhu
- National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China, Guangdong Key Laboratory of Integrated Agro-environmental Pollution Control and Management, Institute of Eco-environmental and Soil Sciences, Guangdong Academy of Sciences, Guangzhou 510650, China
- Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, P. R. China
- University of Chinese Academy of Sciences, Beijing 100049, P. R. China
| | - Xinxin Wang
- National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China, Guangdong Key Laboratory of Integrated Agro-environmental Pollution Control and Management, Institute of Eco-environmental and Soil Sciences, Guangdong Academy of Sciences, Guangzhou 510650, China
- College of Materials and Energy, South China Agricultural University, Guangzhou 510642, China
| | - Zhixin Lin
- National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China, Guangdong Key Laboratory of Integrated Agro-environmental Pollution Control and Management, Institute of Eco-environmental and Soil Sciences, Guangdong Academy of Sciences, Guangzhou 510650, China
| | - John R Reinfelder
- Department of Environmental Sciences, Rutgers University, New Brunswick, New Jersey 08901, United States
| | - Fangbai Li
- National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China, Guangdong Key Laboratory of Integrated Agro-environmental Pollution Control and Management, Institute of Eco-environmental and Soil Sciences, Guangdong Academy of Sciences, Guangzhou 510650, China
| | - Tongxu Liu
- National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China, Guangdong Key Laboratory of Integrated Agro-environmental Pollution Control and Management, Institute of Eco-environmental and Soil Sciences, Guangdong Academy of Sciences, Guangzhou 510650, China
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10
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Zhang J, Wu D, Zhao Y, Liu D, Guo X, Chen Y, Zhang C, Sun X, Guo J, Yuan D, Xiao D, Li F, Song H. Engineering Shewanella oneidensis to efficiently harvest electricity power by co-utilizing glucose and lactate in thin stillage of liquor industry. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 855:158696. [PMID: 36108833 DOI: 10.1016/j.scitotenv.2022.158696] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2022] [Revised: 09/07/2022] [Accepted: 09/07/2022] [Indexed: 06/15/2023]
Abstract
Thin stillage, rich in glucose and lactate, can seriously pollute water resources when directly discharged into the natural environment. Microbial fuel cells (MFC), as a green and sustainable technology, could utilize exoelectrogens to break down organics in wastewater and harvest electricity. Nevertheless, Shewanella oneidensis MR-1, cannot utilize thin stillage for efficient power generation. Here, to enable S. oneidensis to co-utilize glucose and lactate from thin stillage, an engineered S. oneidensis G7∆RSL1 was first created by constructing glucose metabolism pathway, promoting glucose and lactate co-utilization, and enhancing biofilm formation. Then, to enhance biofilm conductivity, we constructed a 3D self-assembled G7∆RSL1-rGO/CNT biohybrid with maximum power density of 560.4 mW m-2 and 373.7 mW m-2 in artificial and actual thin stillage, respectively, the highest among the reported genetically engineered S. oneidensis with thin stillage as carbon source. This study provides a new strategy to facilitate practical applications of MFC in wastewater remediation and efficient power recovery.
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Affiliation(s)
- Junqi Zhang
- School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China; Frontiers Science Center for Synthetic Biology (Ministry of Education), Key Laboratory of Systems Bioengineering, Tianjin University, Tianjin 300072, PR China; Synthetic Biology Research Platform, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China
| | - Deguang Wu
- Key Laboratory of Industrial Fermentation Microbiology (Ministry of Education), Tianjin Industrial Microbiology Key Lab, College of Biotechnology, Tianjin University of Science and Technology, Box 08, No. 29, 13ST. TEDA, Tianjin 300457, PR China; Department of Brewing Engineering, Moutai Institute, Luban Ave, Renhuai 564507, Guizhou, PR China
| | - Yakun Zhao
- School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China; Synthetic Biology Research Platform, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China; Qingdao Institute of Ocean Engineering, Tianjin University, Qingdao 266200, Shandong, China
| | - Dingyuan Liu
- School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China; Frontiers Science Center for Synthetic Biology (Ministry of Education), Key Laboratory of Systems Bioengineering, Tianjin University, Tianjin 300072, PR China; Synthetic Biology Research Platform, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China
| | - Xuewu Guo
- Key Laboratory of Industrial Fermentation Microbiology (Ministry of Education), Tianjin Industrial Microbiology Key Lab, College of Biotechnology, Tianjin University of Science and Technology, Box 08, No. 29, 13ST. TEDA, Tianjin 300457, PR China
| | - Yefu Chen
- Key Laboratory of Industrial Fermentation Microbiology (Ministry of Education), Tianjin Industrial Microbiology Key Lab, College of Biotechnology, Tianjin University of Science and Technology, Box 08, No. 29, 13ST. TEDA, Tianjin 300457, PR China
| | - Cuiying Zhang
- Key Laboratory of Industrial Fermentation Microbiology (Ministry of Education), Tianjin Industrial Microbiology Key Lab, College of Biotechnology, Tianjin University of Science and Technology, Box 08, No. 29, 13ST. TEDA, Tianjin 300457, PR China
| | - Xi Sun
- College of Biological Engineering, Tianjin Agricultural University, Tianjin, PR China
| | - Ju Guo
- Department of Brewing Engineering, Moutai Institute, Luban Ave, Renhuai 564507, Guizhou, PR China
| | - Dezhi Yuan
- Department of Brewing Engineering, Moutai Institute, Luban Ave, Renhuai 564507, Guizhou, PR China
| | - Dongguang Xiao
- Key Laboratory of Industrial Fermentation Microbiology (Ministry of Education), Tianjin Industrial Microbiology Key Lab, College of Biotechnology, Tianjin University of Science and Technology, Box 08, No. 29, 13ST. TEDA, Tianjin 300457, PR China
| | - Feng Li
- School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China.
| | - Hao Song
- Frontiers Science Center for Synthetic Biology (Ministry of Education), Key Laboratory of Systems Bioengineering, Tianjin University, Tianjin 300072, PR China; Synthetic Biology Research Platform, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China; Qingdao Institute of Ocean Engineering, Tianjin University, Qingdao 266200, Shandong, China.
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11
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Effects of UV stress on Shewanella azerbaijanica bioremediation response. RADIOCHIM ACTA 2022. [DOI: 10.1515/ract-2022-0059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Abstract
Shewanella azerbaijanica roles as a live electrode, passing electrons from electron donors to electron acceptors, to gain energy from the extracellular electron transfer (EET) pathway. The present study, considered the quantitative expressions of the major EET reductase genes (mtr cluster), together with uranium removal, live-cell counting, and spectrophotometry in UV-C treated bacteria (0, 60, 120 and 180 s). The simultaneous decline in the uranium removal and cell counting, along with major mtr gene expression patterns (mtrABDEF), approved the negative effects of UV-C radiation on uranium bioreduction in S. azerbaijanica. Uranium removal and cell counting decreased to 25.49% and 0.45 × 109 cells/mL in the 180s UV-C treated sample, respectively at 2 mM uranium concentration, while no decline trend found in 0.5 mM for the counted cells and uranium removal tests. No considerable expression of omcA and omcB (mtrC) genes were traced due to spontaneous mutagenesis during the in vitro serial passages, proposing a novel alternative EET pathway in S. azerbaijanica during uranium bioreduction process. The results could pave the way for further researches to modify the bioremediation process through genetic manipulation.
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12
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Lou J, Cai J, Hu X, Liang Y, Sun Y, Zhu Y, Meng Q, Zhu T, Gao H, Yu Z, Yin J. The stringent starvation protein SspA modulates peptidoglycan synthesis by regulating the expression of peptidoglycan synthases. Mol Microbiol 2022; 118:716-730. [PMID: 36308522 DOI: 10.1111/mmi.14996] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2022] [Revised: 10/19/2022] [Accepted: 10/22/2022] [Indexed: 01/18/2023]
Abstract
The peptidoglycan (PG) layer of bacterial cells is essential for maintaining the cell shape and survival of cells; therefore, the synthesis of PG needs to be spatiotemporally controlled. While it is well established that PG synthesis is mediated posttranslationally through interactions between PG synthases and their cognate partners, much less is known about the transcriptional regulation of genes encoding these synthases. Based on a previous finding that the Gram-negative bacterium Shewanella oneidensis lacking the prominent PG synthase exhibits impaired cell wall integrity, we performed genetic selections to isolate the suppressors. We discovered that disrupting the sspA gene encoding stringent starvation protein A (SspA) is sufficient to suppress compromised PG. SspA serves as a transcriptional repressor that regulates the expression of the two types of PG synthases, class A penicillin-binding proteins and SEDS/bPBP protein complexes. SspA is an RNA polymerase-associated protein, and its regulation involves interactions with the σ70 -RNAP complex and an antagonistic effect of H-NS, a global nucleoid-associated protein. We also present evidence that the regulation of PG synthases by SspA is conserved in Escherichia coli, adding a new dimension to the current understanding of PG synthesis and its regulation.
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Affiliation(s)
- Jie Lou
- College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, China
| | - Jingxiao Cai
- College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, China
| | - Xiao Hu
- College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, China
| | - Yanqun Liang
- College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, China
| | - Yijuan Sun
- College of Life Sciences, Zhejiang University, Hangzhou, China
| | - Yiling Zhu
- College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, China
| | - Qiu Meng
- College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, China
| | - Tingheng Zhu
- College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, China
| | - Haichun Gao
- College of Life Sciences, Zhejiang University, Hangzhou, China
| | - Zhiliang Yu
- College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, China
| | - Jianhua Yin
- College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, China
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13
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Ding DW, Huang WF, Lei LL, Wu P. Co-fitness analysis identifies a diversity of signal proteins involved in the utilization of specific c-type cytochromes. ANN MICROBIOL 2022. [DOI: 10.1186/s13213-022-01694-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Abstract
Purpose
c-Type cytochromes are essential for extracellular electron transfer (EET) in electroactive microorganisms. The expression of appropriate c-type cytochromes is an important feature of these microorganisms in response to different extracellular electron acceptors. However, how these diverse c-type cytochromes are tightly regulated is still poorly understood.
Methods
In this study, we identified the high co-fitness genes that potentially work with different c-type cytochromes by using genome-wide co-fitness analysis. We also constructed and studied the co-fitness networks that composed of c-type cytochromes and the top 20 high co-fitness genes of them.
Results
We found that high co-fitness genes of c-type cytochromes were enriched in signal transduction processes in Shewanella oneidensis MR-1 cells. We then checked the top 20 co-fitness proteins for each of the 41 c-type cytochromes and identified the corresponding signal proteins for different c-type cytochromes. In particular, through the analysis of the high co-fitness signal protein for CymA, we further confirmed the cooperation between signal proteins and c-type cytochromes and identified a novel signal protein that is putatively involved in the regulation of CymA. In addition, we showed that these signal proteins form two signal transduction modules.
Conclusion
Taken together, these findings provide novel insights into the coordinated utilization of different c-type cytochromes under diverse conditions.
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14
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A Common Target of Nitrite and Nitric Oxide for Respiration Inhibition in Bacteria. Int J Mol Sci 2022; 23:ijms232213841. [PMID: 36430319 PMCID: PMC9697910 DOI: 10.3390/ijms232213841] [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: 10/29/2022] [Revised: 11/07/2022] [Accepted: 11/08/2022] [Indexed: 11/12/2022] Open
Abstract
Nitrite and nitric oxide (NO) are well-known bacteriostatic agents with similar biochemical properties. However, many studies have demonstrated that inhibition of bacterial growth by nitrite is independent of NO. Here, with Shewanella oneidensis as the research model because of its unusually high cytochrome (cyt) c content, we identify a common mechanism by which nitrite and NO compromise cyt c biosynthesis in bacteria, and thereby inhibit respiration. This is achieved by eliminating the inference of the cyclic adenosine monophosphate-catabolite repression protein (cAMP-Crp), a primary regulatory system that controls the cyt c content and whose activity is subjected to the repression of nitrite. Both nitrite and NO impair the CcmE of multiple bacteria, an essential heme chaperone of the System I cyt c biosynthesis apparatus. Given that bacterial targets of nitrite and NO differ enormously and vary even in the same genus, these observations underscore the importance of cyt c biosynthesis for the antimicrobial actions of nitrite and NO.
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15
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Stringent Starvation Protein SspA and Iron Starvation Sigma Factor PvdS Coordinately Regulate Iron Uptake and Prodiginine Biosynthesis in
Pseudoalteromonas
sp. R3. Appl Environ Microbiol 2022; 88:e0116422. [PMID: 36326244 PMCID: PMC9680616 DOI: 10.1128/aem.01164-22] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
Both deficiency and excess of intracellular iron can be harmful, and thus, the iron homeostasis needs to be tightly regulated in organisms. At present, the ferric uptake regulator (Fur) is the best-characterized regulator involved in bacterial iron homeostasis, while other regulators of iron homeostasis remain to be further explored.
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16
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Pleiotropic Effects of Hfq on the Cytochrome c Content and Pyomelanin Production in Shewanella oneidensis. Appl Environ Microbiol 2022; 88:e0128922. [PMID: 36073941 PMCID: PMC9499022 DOI: 10.1128/aem.01289-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Shewanella oneidensis is the best understood model microorganism for the study of diverse cytochromes (cytos) c that support its unparallel respiratory versatility. Although RNA chaperone Hfq has been implicated in regulation of cyto c production, little is known about the biological pathways that it affects in this bacterium. In this study, from a spontaneous mutant that secretes pyomelanin and has a lowered cyto c content, we identified Hfq to be the regulator that critically associates with both phenotypes in S. oneidensis. We found that expression of the key genes in biosynthesis and degradation of heme is differentially affected by Hfq at under- and overproduced levels, and through modulating heme levels, Hfq influences the cyto c content. Although Hfq in excess results in overproduction of the enzymes responsible for both generation and removal of homogentisic acid (HGA), the precursor of pyomelanin, it is compromised activity of HmgA that leads to excretion and polymerization of HGA to form pyomelanin. We further show that Hfq mediates HmgA activity by lowering intracellular iron content because HmgA is an iron-dependent enzyme. Overall, our work highlights the significance of Hfq-mediated posttranscriptional regulation in the physiology of S. oneidensis, unraveling unexpected mechanisms by which Hfq affects cyto c biosynthesis and pyomelanin production. IMPORTANCE In bacteria, Hfq has been implicated in regulation of diverse biological processes posttranslationally. In S. oneidensis, Hfq affects the content of cytos c that serve as the basis of its respiratory versatility and potential application in bioenergy and bioremediation. In this study, we found that Hfq differentially regulates heme biosynthesis and degradation, leading to altered cyto c contents. Hfq in excess causes a synthetic effect on HmgA, an enzyme responsible for pyomelanin formation. Overall, the data presented manifest that the biological processes in a given bacterium regulated by Hfq are highly complex, amounting to required coordination among multiple physiological aspects to allow cells to respond to environmental changes promptly.
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17
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Development of Whole-Cell Biosensors for Screening of Peptidoglycan-Targeting Antibiotics in a Gram-Negative Bacterium. Appl Environ Microbiol 2022; 88:e0084622. [PMID: 36040151 PMCID: PMC9499016 DOI: 10.1128/aem.00846-22] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
There is an urgent need to develop novel antibiotics since antibiotic resistance is an increasingly serious threat to global public health. Whole-cell biosensors are one of the promising strategies for new antibiotic discovery. The peptidoglycan (PG) of the bacterial cell wall is one of the most important targets for antibiotics. However, the biosensors for the detection of PG-targeting antibiotics in Gram-negative bacteria have not been developed, mainly because of the lack of the regulatory systems that sense and respond to PG stress. Recently, we identified a novel two-component signal transduction system (PghKR) that is responsible for sensing and responding to PG damage in the Gram-negative bacterium Shewanella oneidensis. Based on this system, we developed biosensors for the detection of PG-targeting antibiotics. Using ampicillin as an inducer for PG stress and the bacterial luciferase LuxCDABE as the reporter, we found that the PghKR biosensors are specific to antibiotics targeting PG synthesis, including β-lactams, vancomycin, and d-cycloserine. Deletion of genes encoding PG permease AmpG and β-lactamase BlaA improves the sensitivity of the biosensors substantially. The PghKR biosensor in the background of ΔblaA is also functional on agar plates, providing a simple method for screening bacteria that produce PG-targeting antibiotics. IMPORTANCE The growing problem of antibiotic resistance in Gram-negative bacteria urgently needs new strategies so that researchers can develop novel antibiotics. Microbial whole-cell biosensors are capable of sensing various stimuli with a quantifiable output and show tremendous potential for the discovery of novel antibiotics. As the Achilles' heel of bacteria, the synthesis of the peptidoglycan (PG) is targeted by many antibiotics. However, the regulatory systems that sense and respond to PG-targeting stress in Gram-negative bacteria are reported rarely, restricting the development of biosensors for the detection of PG-targeting antibiotics. In this study, we developed a highly sensitive and specific biosensor based on a novel two-component system in the Gram-negative bacterium Shewanella oneidensis that is responsible for the sensing and responding to PG stress. Our biosensors have great potential for discovering novel antibiotics and determining the mode of action of antibiotics.
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18
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Wang Y, Fan J, Shen Y, Ye F, Feng Z, Yang Q, Wang D, Cai X, Mao Y. Bromate reduction by Shewanella oneidensis MR-1 is mediated by dimethylsulfoxide reductase. Front Microbiol 2022; 13:955249. [PMID: 36110297 PMCID: PMC9468665 DOI: 10.3389/fmicb.2022.955249] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2022] [Accepted: 08/09/2022] [Indexed: 11/13/2022] Open
Abstract
Microbial bromate reduction plays an important role in remediating bromate-contaminated waters as well as biogeochemical cycling of bromine. However, little is known about the molecular mechanism of microbial bromate reduction so far. Since the model strain Shewanella oneidensis MR-1 is capable of reducing a variety of oxyanions such as iodate, which has a high similarity to bromate, we hypothesize that S. oneidensis MR-1 can reduce bromate. Here, we conducted an experiment to investigate whether S. oneidensis MR-1 can reduce bromate, and report bromate reduction mediated by a dimethylsulfoxide reductase encoded with dmsA. S. oneidensis MR-1 is not a bromate-respiring bacterium but can reduce bromate to bromide under microaerobic conditions. When exposed to 0.15, 0.2, 0.25, 0.5, and 1 mM bromate, S. oneidensis MR-1 reduced bromate by around 100, 75, 64, 48, and 23%, respectively, within 12 h. In vivo evidence from gene deletion mutants and complemented strains of S. oneidensis MR-1 indicates that MtrB, MtrC, CymA, GspD, and DmsA are involved in bromate reduction, but not NapA, FccA, or SYE4. Based on our results as well as previous findings, a proposed molecular mechanism for bromate reduction is presented in this study. Moreover, a genomic survey indicates that 9 of the other 56 reported Shewanella species encode proteins highly homologous to CymA, GspD, and DmsA of S. oneidensis MR-1 by sequence alignment. The results of this study contribute to understanding a pathway for microbial bromate reduction.
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Affiliation(s)
- Yicheng Wang
- College of Chemistry and Environmental Engineering, Shenzhen University, Shenzhen, China
| | - Jiale Fan
- College of Chemistry and Environmental Engineering, Shenzhen University, Shenzhen, China
| | - Yonglin Shen
- College of Chemistry and Environmental Engineering, Shenzhen University, Shenzhen, China
| | - Fan Ye
- College of Chemistry and Environmental Engineering, Shenzhen University, Shenzhen, China
| | - Zhiying Feng
- College of Chemistry and Environmental Engineering, Shenzhen University, Shenzhen, China
| | - Qianning Yang
- College of Chemistry and Environmental Engineering, Shenzhen University, Shenzhen, China
| | - Dan Wang
- College of Chemistry and Environmental Engineering, Shenzhen University, Shenzhen, China
| | - Xunchao Cai
- College of Chemistry and Environmental Engineering, Shenzhen University, Shenzhen, China
- Department of Gastroenterology and Hepatology, Shenzhen University General Hospital, Shenzhen, China
| | - Yanping Mao
- College of Chemistry and Environmental Engineering, Shenzhen University, Shenzhen, China
- *Correspondence: Yanping Mao,
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19
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Li S, Xiao J, Sun T, Yu F, Zhang K, Feng Y, Xu C, Wang B, Cheng L. Synthetic microbial consortia with programmable ecological interactions. Methods Ecol Evol 2022. [DOI: 10.1111/2041-210x.13894] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Shuyao Li
- MOE Key Laboratory of Biosystems Homeostasis & Protection, College of Life Sciences Zhejiang University Hangzhou 310058 China
| | - Jing Xiao
- MOE Key Laboratory of Biosystems Homeostasis & Protection, College of Life Sciences Zhejiang University Hangzhou 310058 China
| | - Tianzheng Sun
- MOE Key Laboratory of Biosystems Homeostasis & Protection, College of Life Sciences Zhejiang University Hangzhou 310058 China
| | - Fangjian Yu
- MOE Key Laboratory of Biosystems Homeostasis & Protection, College of Life Sciences Zhejiang University Hangzhou 310058 China
| | - Kaihang Zhang
- MOE Key Laboratory of Biosystems Homeostasis & Protection, College of Life Sciences Zhejiang University Hangzhou 310058 China
| | - Yuantao Feng
- MOE Key Laboratory of Biosystems Homeostasis & Protection, College of Life Sciences Zhejiang University Hangzhou 310058 China
| | - Chenchao Xu
- MOE Key Laboratory of Biosystems Homeostasis & Protection, College of Life Sciences Zhejiang University Hangzhou 310058 China
| | - Baojun Wang
- Hangzhou Innovation Center & College of Chemical and Biological Engineering Zhejiang University Hangzhou 311200 China
- Research Centre for Biological Computation, Zhejiang Laboratory Hangzhou 311100 China
| | - Lei Cheng
- MOE Key Laboratory of Biosystems Homeostasis & Protection, College of Life Sciences Zhejiang University Hangzhou 310058 China
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20
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Shen S, Sun W, Yang K, Gao H, Lin D. Biotransformation of 2D Nanomaterials through Stimulated Bacterial Respiration-Produced Extracellular Reactive Oxygen Species: A Common but Overlooked Process. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:5508-5519. [PMID: 35420416 DOI: 10.1021/acs.est.1c08481] [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: 06/14/2023]
Abstract
The biotransformation of 2D nanomaterials is still poorly understood, although their environmental fates are becoming an increasing concern with their broad applications. Here, we found that Ti3C2Tx nanosheets, a typical 2D nanomaterial, could be oxidized by reactive oxygen species (ROS) produced by both Gram-negative (Escherichia coli and Shewanella oneidensis) and Gram-positive (Bacillus subtilis) bacteria, with the formation of titanium dioxide (TiO2) on the nanosheet surfaces and impairment of structural integrity. Specifically, Ti3C2Tx nanosheets stimulated bacterial respiration Complex I, leading to increased generation of extracellular O2•- and the formation of H2O2 and •OH via Fenton-like reactions, which intensified the oxidation of the nanosheets. Surface modifications with KOH and hydrazine (HMH), especially HMH, could limit bacterial oxidation of the nanosheets. These findings reveal a common but overlooked process in which oxygen-respiring bacteria are capable of oxidizing 2D nanosheets, providing new knowledge for environmental fate evaluation and future design of functional 2D nanomaterials.
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Affiliation(s)
- Shuyi Shen
- Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control, Department of Environmental Science, Zhejiang University, Hangzhou 310058, China
| | - Weining Sun
- Institute of Microbiology, College of Life Sciences, Zhejiang University, Hangzhou 310058, China
| | - Kun Yang
- Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control, Department of Environmental Science, Zhejiang University, Hangzhou 310058, China
| | - Haichun Gao
- Institute of Microbiology, College of Life Sciences, Zhejiang University, Hangzhou 310058, China
| | - Daohui Lin
- Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control, Department of Environmental Science, Zhejiang University, Hangzhou 310058, China
- Zhejiang Ecological Civilization Academy, Anji 313300, China
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Functional Irreplaceability of Escherichia coli and Shewanella oneidensis OxyRs Is Critically Determined by Intrinsic Differences in Oligomerization. mBio 2022; 13:e0349721. [PMID: 35073744 PMCID: PMC8787470 DOI: 10.1128/mbio.03497-21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
LysR-type transcriptional regulators (LTTRs), which function in diverse biological processes in prokaryotes, are composed of a conserved structure with an N-terminal DNA-binding domain (DBD) and a C-terminal signal-sensing regulatory domain (RD). LTTRs that sense and respond to the same signal are often functionally exchangeable in bacterial species across wide phyla, but this phenomenon has not been demonstrated for the H2O2-sensing and -responding OxyRs. Here, we systematically examined the biochemical and structural determinants differentiating activator-only OxyRs from dual-activity ones by comparing OxyRs from two Gammaproteobacteria, Escherichia coli and Shewanella oneidensis. Our data show that EcOxyR could function as neither an activator nor a repressor in S. oneidensis. Using SoOxyR-based OxyR chimeras and mutants, we demonstrated that residues 283 to 289, which form the first half of the last C-terminal α-helix (α10), are critical for the proper function of SoOxyR and cannot be replaced with the EcOxyR counterpart. Crystal structural analysis reveals that α10 is important for the oligomerization of SoOxyR, which, unlike EcOxyR, forms several high-order oligomers upon DNA binding. As the mechanisms of OxyR oligomerization vary substantially among bacterial species, our findings underscore the importance of subtle structural features in determining regulatory activities of structurally similar proteins descending from a common ancestor. IMPORTANCE Evolution may drive homologous proteins to be functionally nonexchangeable in different organisms. However, much is unknown about the mechanisms underlying this phenomenon beyond amino acid substitutions. Here, we systematically examined the biochemical and structural determinants differentiating functionally nonexchangeable OxyRs, H2O2-responding transcriptional regulators from two Gammaproteobacteria, Escherichia coli and Shewanella oneidensis. Using SoOxyR-based OxyR chimeras and mutants, we demonstrated that residues 283 to 289, which form the first half of the last C-terminal α-helix (α10), are critical for the proper function of SoOxyR and cannot be replaced with the EcOxyR counterpart. Crystal structural analysis reveals that this last helix is critical for formation of high-order oligomers upon DNA binding, a phenomenon not observed with EcOxyR. Our findings provide a new dimension to differences in sequence and structural features among bacterial species in determining regulatory activities of homologous regulators.
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Guo K, Feng X, Sun W, Han S, Wu S, Gao H. NapB Restores cytochrome c biosynthesis in bacterial dsbD-deficient mutants. Commun Biol 2022; 5:87. [PMID: 35064202 PMCID: PMC8782879 DOI: 10.1038/s42003-022-03034-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Accepted: 01/05/2022] [Indexed: 11/10/2022] Open
Abstract
Cytochromes c (cyts c), essential for respiration and photosynthesis in eukaryotes, confer bacteria respiratory versatility for survival and growth in natural environments. In bacteria having a cyt c maturation (CCM) system, DsbD is required to mediate electron transport from the cytoplasm to CcmG of the Ccm apparatus. Here with cyt c-rich Shewanella oneidensis as the research model, we identify NapB, a cyt c per se, that suppresses the CCM defect of a dsbD mutant during anaerobiosis, when NapB is produced at elevated levels, a result of activation by cAMP-Crp. Data are then presented to suggest that NapB reduces CcmG, leading to the suppression. We further show that NapB proteins capable of rescuing CCM in the dsbD mutant form a small distinct clade. The study sheds light on multifunctionality of cyts c, and more importantly, unravels a self-salvation strategy through which bacteria have evolved to better adjust to the natural world. The DsbD protein is normally required for cytochrome c maturation (Ccm) in bacteria. With cytochrome c-rich Shewanella oneidensis as the research model, NapB, the small subunit of the nitrate reductase which is a cytochrome c per se, was found to suppress the Ccm defect resulting from DsbD loss under anaerobic conditions.
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23
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Zarei M, Mir-Derikvand M, Hosseinpour H, Samani TR, Ghasemi R, Fatemi F. U (VI) tolerance affects Shewanella sp. RCRI7 biological responses: growth, morphology and bioreduction ability. Arch Microbiol 2021; 204:81. [PMID: 34958431 DOI: 10.1007/s00203-021-02716-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Revised: 10/30/2021] [Accepted: 11/19/2021] [Indexed: 11/27/2022]
Abstract
Native Shewanella sp. RCRI7 is recently counted as an operative bacterium in the uranium bio-reduction. The aim of this study was to investigate the effects of uranium tolerance on the morphology and population of RCRI7, following its potential removal capacity in different time intervals. In this research, the bacterial growth and uranium removal kinetic were evaluated in aerobic TSB medium, uranium-reducing condition (URC), aerobic uranium-containing (AUC) and anaerobic uranium-free (AUF) solution, following evaluations of omcAB gene expressions. In addition, spectrophotometry analyses were performed in URC confirming the bio-reduction mechanism. It was found that the bacteria can grow efficiently in the presence of 0.5 mM uranium anaerobically, unlike AUC and AUF solutions. Since the bacterium's adsorption capacity is quickly saturated, it can be deduced that uranium reduction should be dominant as incubation times proceed up to 84 h in URC. In 92 h incubation, the adsorbed uranium containing unreduced and reduced (U (IV) monomeric), was released to the solution due to either increased pH or bacterial death. In AUC and AUF, improper conditions lead to the reduced bacterial size (coccus-shape formation) and increased bacterial aggregations; however, membrane vesicles produced by the bacteria avoid the uranium incrustation in AUC. In overall, this study implies that Shewanella sp. RCRI7 are well tolerated by uranium under anaerobic conditions and the amount of regenerated uranium increases over time in the reduced form.
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Affiliation(s)
- Mahsa Zarei
- Department of Life Science Engineering, Faculty of New Sciences and Technologies, University of Tehran, Tehran, Iran
| | - Mohammad Mir-Derikvand
- Department of Life Science Engineering, Faculty of New Sciences and Technologies, University of Tehran, Tehran, Iran
| | | | | | - Razieh Ghasemi
- Department of Life Science Engineering, Faculty of New Sciences and Technologies, University of Tehran, Tehran, Iran
| | - Faezeh Fatemi
- Nuclear Fuel Cycle Research School, Nuclear Science and Technology Research Institute, Tehran, Iran.
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Sun W, Lin Z, Yu Q, Cheng S, Gao H. Promoting Extracellular Electron Transfer of Shewanella oneidensis MR-1 by Optimizing the Periplasmic Cytochrome c Network. Front Microbiol 2021; 12:727709. [PMID: 34675900 PMCID: PMC8524038 DOI: 10.3389/fmicb.2021.727709] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2021] [Accepted: 09/13/2021] [Indexed: 11/13/2022] Open
Abstract
The low efficiency of extracellular electron transfer (EET) is a major bottleneck for Shewanella oneidensis MR-1 acting as an electroactive biocatalyst in bioelectrochemical systems. Although it is well established that a periplasmic c-type cytochrome (c-Cyt) network plays a critical role in regulating EET efficiency, the understanding of the network in terms of structure and electron transfer activity is obscure and partial. In this work, we attempted to systematically investigate the impacts of the network components on EET in their absence and overproduction individually in microbial fuel cell (MFC). We found that overexpression of c-Cyt CctA leads to accelerated electron transfer between CymA and the Mtr system, which function as the primary quinol oxidase and the outer-membrane (OM) electron hub in EET. In contrast, NapB, FccA, and TsdB in excess severely impaired EET, reducing EET capacity in MFC by more than 50%. Based on the results from both strategies, a series of engineered strains lacking FccA, NapB, and TsdB in combination while overproducing CctA were tested for a maximally optimized c-Cyt network. A strain depleted of all NapB, FccA, and TsdB with CctA overproduction achieved the highest maximum power density in MFCs (436.5 mW/m2), ∼3.62-fold higher than that of wild type (WT). By revealing that optimization of periplasmic c-Cyt composition is a practical strategy for improving EET efficiency, our work underscores the importance in understanding physiological and electrochemical characteristics of c-Cyts involved in EET.
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Affiliation(s)
- Weining Sun
- Institute of Microbiology and College of Life Sciences, Zhejiang University, Hangzhou, China
| | - Zhufan Lin
- Department of Energy Engineering, State Key Laboratory of Clean Energy, Zhejiang University, Hangzhou, China
| | - Qingzi Yu
- Institute of Microbiology and College of Life Sciences, Zhejiang University, Hangzhou, China
| | - Shaoan Cheng
- Department of Energy Engineering, State Key Laboratory of Clean Energy, Zhejiang University, Hangzhou, China
| | - Haichun Gao
- Institute of Microbiology and College of Life Sciences, Zhejiang University, Hangzhou, China
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25
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Yu Q, Sun W, Gao H. Thiosulfate oxidation in sulfur-reducing Shewanella oneidensis and its unexpected influences on the cytochrome c content. Environ Microbiol 2021; 23:7056-7072. [PMID: 34664382 DOI: 10.1111/1462-2920.15807] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Revised: 09/04/2021] [Accepted: 10/07/2021] [Indexed: 12/13/2022]
Abstract
Thiosulfate, an important form of sulfur compounds, can serve as both electron donor and acceptor in various microorganisms. In Shewanella oneidensis, a bacterium renowned for respiratory versatility, thiosulfate reduction has long been recognized but whether it can catalyse thiosulfate oxidation remains elusive. In this study, we discovered that S. oneidensis is capable of thiosulfate oxidation, a process specifically catalysed by two periplasmic cytochrome c (cyt c) proteins, TsdA and TsdB, which act as the catalytic subunit and the electron transfer subunit respectively. In the presence of oxygen, oxidation of thiosulfate has priority over reduction. Intriguingly, thiosulfate oxidation negatively regulates the cyt c content in S. oneidensis cells, largely by reducing intracellular levels of cAMP, which as the cofactor modulates activity of global regulator Crp required for transcription of many cyt c genes. This unexpected finding provides an additional dimension to interplays between the respiration regulator and the respiratory pathways in S. oneidensis. Moreover, the data presented here identified S. oneidensis as the first bacterium known to date owning both functional thiosulfate reductase and dehydrogenase, and importantly, genomics analyses suggested that the number of bacterial species possessing this feature is rather limited.
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Affiliation(s)
- Qingzi Yu
- Institute of Microbiology and College of Life Sciences, Zhejiang University, Zhejiang, Hangzhou, 310058, China
| | - Weining Sun
- Institute of Microbiology and College of Life Sciences, Zhejiang University, Zhejiang, Hangzhou, 310058, China
| | - Haichun Gao
- Institute of Microbiology and College of Life Sciences, Zhejiang University, Zhejiang, Hangzhou, 310058, China
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26
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Piper SEH, Edwards MJ, van Wonderen JH, Casadevall C, Martel A, Jeuken LJC, Reisner E, Clarke TA, Butt JN. Bespoke Biomolecular Wires for Transmembrane Electron Transfer: Spontaneous Assembly of a Functionalized Multiheme Electron Conduit. Front Microbiol 2021; 12:714508. [PMID: 34484155 PMCID: PMC8415449 DOI: 10.3389/fmicb.2021.714508] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2021] [Accepted: 07/12/2021] [Indexed: 11/13/2022] Open
Abstract
Shewanella oneidensis exchanges electrons between cellular metabolism and external redox partners in a process that attracts much attention for production of green electricity (microbial fuel cells) and chemicals (microbial electrosynthesis). A critical component of this pathway is the outer membrane spanning MTR complex, a biomolecular wire formed of the MtrA, MtrB, and MtrC proteins. MtrA and MtrC are decaheme cytochromes that form a chain of close-packed hemes to define an electron transfer pathway of 185 Å. MtrA is wrapped inside MtrB for solubility across the outer membrane lipid bilayer; MtrC sits outside the cell for electron exchange with external redox partners. Here, we demonstrate tight and spontaneous in vitro association of MtrAB with separately purified MtrC. The resulting complex is comparable with the MTR complex naturally assembled by Shewanella in terms of both its structure and rates of electron transfer across a lipid bilayer. Our findings reveal the potential for building bespoke electron conduits where MtrAB combines with chemically modified MtrC, in this case, labeled with a Ru-dye that enables light-triggered electron injection into the MtrC heme chain.
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Affiliation(s)
- Samuel E H Piper
- School of Chemistry and School of Biological Sciences, University of East Anglia, Norwich, United Kingdom
| | - Marcus J Edwards
- School of Chemistry and School of Biological Sciences, University of East Anglia, Norwich, United Kingdom
| | - Jessica H van Wonderen
- School of Chemistry and School of Biological Sciences, University of East Anglia, Norwich, United Kingdom
| | - Carla Casadevall
- Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, United Kingdom
| | | | - Lars J C Jeuken
- School of Biomedical Sciences, University of Leeds, Leeds, United Kingdom
| | - Erwin Reisner
- Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, United Kingdom
| | - Thomas A Clarke
- School of Chemistry and School of Biological Sciences, University of East Anglia, Norwich, United Kingdom
| | - Julea N Butt
- School of Chemistry and School of Biological Sciences, University of East Anglia, Norwich, United Kingdom
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27
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Xie P, Wang J, Liang H, Gao H. Shewanella oneidensis arcA Mutation Impairs Aerobic Growth Mainly by Compromising Translation. Life (Basel) 2021; 11:life11090926. [PMID: 34575075 PMCID: PMC8470723 DOI: 10.3390/life11090926] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Revised: 08/30/2021] [Accepted: 08/30/2021] [Indexed: 12/27/2022] Open
Abstract
Arc (anoxic redox control), one of the most intensely investigated two-component regulatory systems in γ-proteobacteria, plays a major role in mediating the metabolic transition from aerobiosis to anaerobiosis. In Shewanella oneidensis, a research model for respiratory versatility, Arc is crucial for aerobic growth. However, how this occurs remains largely unknown. In this study, we demonstrated that the loss of the response regulator ArcA distorts the correlation between transcription and translation by inhibiting the ribosome biosynthesis. This effect largely underlies the growth defect because it concurs with the effect of chloramphenicol, which impairs translation. Reduced transcription of ArcA-dependent ribosomal protein S1 appears to have a significant impact on ribosome assembly. We further show that the lowered translation efficiency is not accountable for the envelope defect, another major defect resulting from the ArcA loss. Overall, our results suggest that although the arcA mutation impairs growth through multi-fold complex impacts in physiology, the reduced translation efficacy appears to be a major cause for the phenotype, demonstrating that Arc is a primary system that coordinates proteomic resources with metabolism in S. oneidensis.
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28
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Lipopolysaccharide Transport System Links Physiological Roles of σ E and ArcA in the Cell Envelope Biogenesis in Shewanella oneidensis. Microbiol Spectr 2021; 9:e0069021. [PMID: 34406804 PMCID: PMC8552667 DOI: 10.1128/spectrum.00690-21] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
The bacterial cell envelope is not only a protective structure that surrounds the cytoplasm but also the place where a myriad of biological processes take place. This multilayered complex is particularly important for electroactive bacteria such as Shewanella oneidensis, as it generally hosts branched electron transport chains and numerous reductases for extracellular respiration. However, little is known about how the integrity of the cell envelope is established and maintained in these bacteria. By tracing the synthetic lethal effect of Arc two-component system and σE in S. oneidensis, in this study, we identified the lipopolysaccharide transport (Lpt) system as the determining factor. Both Arc and σE, by regulating transcription of lptFG and lptD, respectively, are required for the Lpt system to function properly. The ArcA loss results in an LptFG shortage that triggers activation of σE and leads to LptD overproduction. LptFG and LptD at abnormal levels cause a defect in the lipopolysaccharide (LPS) transport, leading to cell death unless σE-dependent envelope stress response is in place. Overall, our report reveals for the first time that Arc works together with σE to maintain the integrity of the S. oneidensis cell envelope by participating in the regulation of the LPS transport system. IMPORTANCE Arc is a well-characterized global regulatory system that modulates cellular respiration by responding to changes in the redox status in bacterial cells. In addition to regulating expression of respiratory enzymes, Shewanella oneidensis Arc also plays a critical role in cell envelope integrity. The absence of Arc and master envelope stress response (ESR) regulator σE causes a synthetic lethal phenotype. Our research shows that the Arc loss downregulates lptFG expression, leading to cell envelope defects that require σE-mediated ESR for viability. The complex mechanisms revealed here underscore the importance of the interplay between global regulators in bacterial adaption to their natural inhabits.
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29
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Liu X, Lin S, Liu T, Zhou Y, Wang W, Yao J, Guo Y, Tang K, Chen R, Benedik MJ, Wang X. Xenogeneic silencing relies on temperature-dependent phosphorylation of the host H-NS protein in Shewanella. Nucleic Acids Res 2021; 49:3427-3440. [PMID: 33693785 PMCID: PMC8034616 DOI: 10.1093/nar/gkab137] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Revised: 02/17/2021] [Accepted: 02/20/2021] [Indexed: 12/20/2022] Open
Abstract
Lateral gene transfer (LGT) plays a key role in shaping the genome evolution and environmental adaptation of bacteria. Xenogeneic silencing is crucial to ensure the safe acquisition of LGT genes into host pre-existing regulatory networks. We previously found that the host nucleoid structuring protein (H-NS) silences prophage CP4So at warm temperatures yet enables this prophage to excise at cold temperatures in Shewanella oneidensis. However, whether H-NS silences other genes and how bacteria modulate H-NS to regulate the expression of genes have not been fully elucidated. In this study, we discovered that the H-NS silences many LGT genes and the xenogeneic silencing of H-NS relies on a temperature-dependent phosphorylation at warm temperatures in S. oneidensis. Specifically, phosphorylation of H-NS at Ser42 is critical for silencing the cold-inducible genes including the excisionase of CP4So prophage, a cold shock protein, and a stress-related chemosensory system. By contrast, nonphosphorylated H-NS derepresses the promoter activity of these genes/operons to enable their expression at cold temperatures. Taken together, our results reveal that the posttranslational modification of H-NS can function as a regulatory switch to control LGT gene expression in host genomes to enable the host bacterium to react and thrive when environmental temperature changes.
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Affiliation(s)
- Xiaoxiao Liu
- Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, Innovation Academy of South China Sea Ecology and Environmental Engineering, South China Sea Institute of Oceanology, Chinese Academy of Sciences, No. 1119, Haibin Road, Nansha District, Guangzhou 511458, China.,Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), No.1119, Haibin Road, Nansha District, Guangzhou 511458, China
| | - Shituan Lin
- Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, Innovation Academy of South China Sea Ecology and Environmental Engineering, South China Sea Institute of Oceanology, Chinese Academy of Sciences, No. 1119, Haibin Road, Nansha District, Guangzhou 511458, China.,Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), No.1119, Haibin Road, Nansha District, Guangzhou 511458, China.,University of Chinese Academy of Sciences, Beijing 100049, China
| | - Tianlang Liu
- Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, Innovation Academy of South China Sea Ecology and Environmental Engineering, South China Sea Institute of Oceanology, Chinese Academy of Sciences, No. 1119, Haibin Road, Nansha District, Guangzhou 511458, China.,Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), No.1119, Haibin Road, Nansha District, Guangzhou 511458, China.,University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yiqing Zhou
- Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, Innovation Academy of South China Sea Ecology and Environmental Engineering, South China Sea Institute of Oceanology, Chinese Academy of Sciences, No. 1119, Haibin Road, Nansha District, Guangzhou 511458, China.,Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), No.1119, Haibin Road, Nansha District, Guangzhou 511458, China.,University of Chinese Academy of Sciences, Beijing 100049, China
| | - Weiquan Wang
- Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, Innovation Academy of South China Sea Ecology and Environmental Engineering, South China Sea Institute of Oceanology, Chinese Academy of Sciences, No. 1119, Haibin Road, Nansha District, Guangzhou 511458, China.,Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), No.1119, Haibin Road, Nansha District, Guangzhou 511458, China.,University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jianyun Yao
- Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, Innovation Academy of South China Sea Ecology and Environmental Engineering, South China Sea Institute of Oceanology, Chinese Academy of Sciences, No. 1119, Haibin Road, Nansha District, Guangzhou 511458, China.,Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), No.1119, Haibin Road, Nansha District, Guangzhou 511458, China
| | - Yunxue Guo
- Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, Innovation Academy of South China Sea Ecology and Environmental Engineering, South China Sea Institute of Oceanology, Chinese Academy of Sciences, No. 1119, Haibin Road, Nansha District, Guangzhou 511458, China.,Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), No.1119, Haibin Road, Nansha District, Guangzhou 511458, China.,University of Chinese Academy of Sciences, Beijing 100049, China
| | - Kaihao Tang
- Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, Innovation Academy of South China Sea Ecology and Environmental Engineering, South China Sea Institute of Oceanology, Chinese Academy of Sciences, No. 1119, Haibin Road, Nansha District, Guangzhou 511458, China.,Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), No.1119, Haibin Road, Nansha District, Guangzhou 511458, China
| | - Ran Chen
- Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, Innovation Academy of South China Sea Ecology and Environmental Engineering, South China Sea Institute of Oceanology, Chinese Academy of Sciences, No. 1119, Haibin Road, Nansha District, Guangzhou 511458, China.,Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), No.1119, Haibin Road, Nansha District, Guangzhou 511458, China
| | - Michael J Benedik
- Department of Biology, Texas A&M University, College Station, TX 77843, USA
| | - Xiaoxue Wang
- Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, Innovation Academy of South China Sea Ecology and Environmental Engineering, South China Sea Institute of Oceanology, Chinese Academy of Sciences, No. 1119, Haibin Road, Nansha District, Guangzhou 511458, China.,Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), No.1119, Haibin Road, Nansha District, Guangzhou 511458, China.,University of Chinese Academy of Sciences, Beijing 100049, China
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Wan F, Feng X, Yin J, Gao H. Distinct H 2O 2-Scavenging System in Yersinia pseudotuberculosis: KatG and AhpC Act Together to Scavenge Endogenous Hydrogen Peroxide. Front Microbiol 2021; 12:626874. [PMID: 34025596 PMCID: PMC8139631 DOI: 10.3389/fmicb.2021.626874] [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: 11/07/2020] [Accepted: 03/22/2021] [Indexed: 01/09/2023] Open
Abstract
To colonize in the digestive tract of animals and humans, Yersinia pseudotuberculosis has to deal with reactive oxygen species (ROS) produced by host cells and microbiota. However, an understanding of the ROS-scavenging systems and their regulation in this bacterium remains largely elusive. In this study, we identified OxyR as the master transcriptional regulator mediating cellular responses to hydrogen peroxide (H2O2) in Y. pseudotuberculosis through genomics and transcriptomics analyses. OxyR activates transcription of diverse genes, especially the core members of its regulon, including those encoding catalases, peroxidases, and thiol reductases. The data also suggest that sulfur species and manganese may play a particular role in the oxidative stress response of Y. pseudotuberculosis. Among the three H2O2-scavenging systems in Y. pseudotuberculosis, catalase/peroxidase KatE functions as the primary scavenger for high levels of H2O2; NADH peroxidase alkyl hydroperoxide reductase (AhpR) and catalase KatG together are responsible for removing low levels of H2O2. The simultaneous loss of both AhpC (the peroxidatic component of AhpR) and KatG results in activation of OxyR. Moreover, we found that AhpC, unlike its well-characterized Escherichia coli counterpart, has little effect on protecting cells against toxicity of organic peroxides. These findings provide not only novel insights into the structural and functional diversity of bacterial H2O2-scavenging systems but also a basic understanding of how Y. pseudotuberculosis copes with oxidative stress.
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Affiliation(s)
- Fen Wan
- College of Laboratory Medicine, Hangzhou Medical College, Hangzhou, China
| | - Xue Feng
- Institute of Microbiology and College of Life Sciences, Zhejiang University, Hangzhou, China
| | - Jianhua Yin
- College of Biotechnology and Bioengineering, Zhenjiang University of Technology, Hangzhou, China
| | - Haichun Gao
- Institute of Microbiology and College of Life Sciences, Zhejiang University, Hangzhou, China
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31
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Stringent Starvation Protein Regulates Prodiginine Biosynthesis via Affecting Siderophore Production in Pseudoalteromonas sp. Strain R3. Appl Environ Microbiol 2021; 87:AEM.02949-20. [PMID: 33483309 DOI: 10.1128/aem.02949-20] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Accepted: 01/17/2021] [Indexed: 12/18/2022] Open
Abstract
Prodiginines are a family of red-pigmented secondary metabolites with multiple biological activities. The biosynthesis of prodiginines is affected by various physiological and environmental factors. Thus, prodiginine biosynthesis regulation is highly complex and multifaceted. Although the regulatory mechanism for prodiginine biosynthesis has been extensively studied in Serratia and Streptomyces species, little is known about that in the marine betaproteobacterium Pseudoalteromonas In this study, we report that stringent starvation protein A (SspA), an RNA polymerase-associated regulatory protein, is required for the biosynthesis of prodiginine in Pseudoalteromonas sp. strain R3. The strain lacking sspA (ΔsspA) fails to produce prodiginine, which resulted from the downregulation of the prodiginine biosynthetic gene (pig) cluster. The effect of SspA on prodiginine biosynthesis is independent of histone-like nucleoid structuring protein (H-NS) and RpoS (σS). Further analysis demonstrates that the ΔsspA strain has a significant decrease in the transcription of the siderophore biosynthesis gene (pvd) cluster, leading to the inhibition of siderophore production and iron uptake. The ΔsspA strain regains the ability to synthesize prodiginine by cocultivation with siderophore producers or the addition of iron. Therefore, we conclude that SspA-regulated prodiginine biosynthesis is due to decreased siderophore levels and iron deficiency. We further show that the iron homeostasis master regulator Fur is also essential for pig transcription and prodiginine biosynthesis. Overall, our results suggest that SspA indirectly regulates the biosynthesis of prodiginine, which is mediated by the siderophore-dependent iron uptake pathway.IMPORTANCE The red-pigmented prodiginines are attracting increasing interest due to their broad biological activities. As with many secondary metabolites, the biosynthesis of prodiginines is regulated by both environmental and physiological factors. At present, studies on the regulation of prodiginine biosynthesis are mainly restricted to Serratia and Streptomyces species. This work focused on the regulatory mechanism of prodiginine biosynthesis in Pseudoalteromonas sp. R3. We found that stringent starvation protein A (SspA) positively regulates prodiginine biosynthesis via affecting the siderophore-dependent iron uptake pathway. The connections among SspA, iron homeostasis, and prodiginine biosynthesis were investigated. These findings uncover a novel regulatory mechanism for prodigiosin biosynthesis.
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Evidence for Horizontal and Vertical Transmission of Mtr-Mediated Extracellular Electron Transfer among the Bacteria. mBio 2021; 13:e0290421. [PMID: 35100867 PMCID: PMC8805035 DOI: 10.1128/mbio.02904-21] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Some bacteria and archaea have evolved the means to use extracellular electron donors and acceptors for energy metabolism, a phenomenon broadly known as extracellular electron transfer (EET). One such EET mechanism is the transmembrane electron conduit MtrCAB, which has been shown to transfer electrons derived from metabolic substrates to electron acceptors, like Fe(III) and Mn(IV) oxides, outside the cell. Although most studies of MtrCAB-mediated EET have been conducted in Shewanella oneidensis MR-1, recent investigations in Vibrio and Aeromonas species have revealed that the electron-donating proteins that support MtrCAB in Shewanella are not as representative as previously thought. This begs the question of how widespread the capacity for MtrCAB-mediated EET is, the changes it has accrued in different lineages, and where these lineages persist today. Here, we employed a phylogenetic and comparative genomics approach to identify the MtrCAB system across all domains of life. We found mtrCAB in the genomes of numerous diverse Bacteria from a wide range of environments, and the patterns therein strongly suggest that mtrCAB was distributed through both horizontal and subsequent vertical transmission, and with some cases indicating downstream modular diversification of both its core and accessory components. Our data point to an emerging evolutionary story about metal-oxidizing and -reducing metabolism, demonstrates that this capacity for EET has broad relevance to a diversity of taxa and the biogeochemical cycles they drive, and lays the foundation for further studies to shed light on how this mechanism may have coevolved with Earth's redox landscape. IMPORTANCE While many metabolisms make use of soluble, cell-permeable substrates like oxygen or hydrogen, there are other substrates, like iron or manganese, that cannot be brought into the cell. Some bacteria and archaea have evolved the means to directly "plug in" to such environmental electron reservoirs in a process known as extracellular electron transfer (EET), making them powerful agents of biogeochemical change and promising vehicles for bioremediation and alternative energy. Yet the diversity, distribution, and evolution of EET mechanisms are poorly constrained. Here, we present findings showing that the genes encoding one such EET system (mtrCAB) are present in a broad diversity of bacteria found in a wide range of environments, emphasizing the ubiquity and potential impact of EET in our biosphere. Our results suggest that these genes have been disseminated largely through horizontal transfer, and the changes they have accrued in these lineages potentially reflect adaptations to changing environments.
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Bao X, Wang F, Yang R, Zhang Y, Fu L, Wang Y. Ornithine Decarboxylation System of Shewanella baltica Regulates Putrescine Production and Acid Resistance. J Food Prot 2021; 84:303-309. [PMID: 33003195 DOI: 10.4315/jfp-20-227] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Accepted: 09/30/2020] [Indexed: 01/18/2023]
Abstract
ABSTRACT Shewanella baltica, one of the dominant spoilers of seafoods, can synthesize putrescine from ornithine under acidic conditions, which could result in food spoilage and health problems. We identified three regulatory enzymes (SpeC, SpeF, and PotE) in the ornithine decarboxylation (ODC) pathway of S. baltica by searching the NCBI database and exploring their functional roles through gene knock-out technology. The ornithine decarboxylase SpeC is an auxiliary adjustor of the ODC system, whereas the ornithine-putrescine transporter SpeE and ornithine decarboxylase SpeF participate in the production of extracellular putrescine. Exogenous addition of ornithine and putrescine promotes the extracellular secretion of putrescine by upregulating the expression of speF and potE. The putrescine biosynthesis and alkalization of cytoplasm is enhanced at weak acidic pH compared with neutral pH, especially at pH 6.0. The maximum upregulation of ODC genes and the optimum decarboxylation activity of SpeF are achieved in a weak acidic environment (pH 6.0), suggesting that the ODC pathway plays an important role in putrescine production and the cytoplasmic acid counteraction of S. baltica. This study contributes to a wider understanding of spoilage mechanisms in food systems and provides theoretical support for developing novel seafood preservation methods. HIGHLIGHTS
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Affiliation(s)
- Xingyue Bao
- Food Safety Key Laboratory of Zhejiang Province, School of Food Science and Biotechnology, Zhejiang Gongshang University, Hangzhou 310018, People's Republic of China
| | - Feifei Wang
- Food Safety Key Laboratory of Zhejiang Province, School of Food Science and Biotechnology, Zhejiang Gongshang University, Hangzhou 310018, People's Republic of China
| | - Rendi Yang
- Food Safety Key Laboratory of Zhejiang Province, School of Food Science and Biotechnology, Zhejiang Gongshang University, Hangzhou 310018, People's Republic of China
| | - Yan Zhang
- Hebei Food Inspection and Research Institute, Shijiazhuang 050091, People's Republic of China
| | - Linglin Fu
- Food Safety Key Laboratory of Zhejiang Province, School of Food Science and Biotechnology, Zhejiang Gongshang University, Hangzhou 310018, People's Republic of China
| | - Yanbo Wang
- Food Safety Key Laboratory of Zhejiang Province, School of Food Science and Biotechnology, Zhejiang Gongshang University, Hangzhou 310018, People's Republic of China
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Liu L, Feng X, Wang W, Chen Y, Chen Z, Gao H. Free Rather Than Total Iron Content Is Critically Linked to the Fur Physiology in Shewanella oneidensis. Front Microbiol 2020; 11:593246. [PMID: 33329474 PMCID: PMC7732582 DOI: 10.3389/fmicb.2020.593246] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Accepted: 09/29/2020] [Indexed: 11/30/2022] Open
Abstract
Ferric uptake regulator (Fur) is a transcriptional regulator playing a central role in iron homeostasis of many bacteria, and Fur inactivation commonly results in pleiotropic phenotypes. In Shewanella oneidensis, a representative of dissimilatory metal-reducing γ-proteobacteria capable of respiring a variety of chemicals as electron acceptors (EAs), Fur loss substantially impairs respiration. However, to date the mechanism underlying the physiological phenomenon remains obscure. This investigation reveals that Fur loss compromises activity of iron proteins requiring biosynthetic processes for their iron cofactors, heme in particular. We then show that S. oneidensis Fur is critical for maintaining heme homeostasis by affecting both its biosynthesis and decomposition of the molecule. Intriguingly, the abundance of iron-containing proteins controlled by H2O2-responding regulator OxyR increases in the fur mutant because the Fur loss activates OxyR. By comparing suppression of membrane-impermeable, membrane-permeable, and intracellular-only iron chelators on heme deficiency and elevated H2O2 resistance, our data suggest that the elevation of the free iron content by the Fur loss is likely to be the predominant factor for the Fur physiology. Overall, these results provide circumstantial evidence that Fur inactivation disturbs bacterial iron homeostasis by altering transcription of its regulon members, through which many physiological processes, such as respiration and oxidative stress response, are transformed.
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Affiliation(s)
| | | | | | | | | | - Haichun Gao
- Institute of Microbiology, College of Life Sciences, Zhejiang University, Hangzhou, China
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Evaluation of mtr cluster expression in Shewanella RCRI7 during uranium removal. Arch Microbiol 2020; 202:2711-2726. [DOI: 10.1007/s00203-020-01981-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2020] [Revised: 07/03/2020] [Accepted: 07/10/2020] [Indexed: 11/30/2022]
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Feng X, Guo K, Gao H. Plasticity of the peroxidase AhpC links multiple substrates to diverse disulfide-reducing pathways in Shewanella oneidensis. J Biol Chem 2020; 295:11118-11130. [PMID: 32532818 DOI: 10.1074/jbc.ra120.014010] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2020] [Revised: 05/29/2020] [Indexed: 12/25/2022] Open
Abstract
AhpC is a bacterial representative of 2-Cys peroxiredoxins (Prxs) with broad substrate specificity and functional plasticity. However, details underpinning these two important attributes of AhpC remain unclear. Here, we studied the functions and mechanisms of regulation of AhpC in the facultative Gram-negative anaerobic bacterium Shewanella oneidensis, in which AhpC's physiological roles can be conveniently assessed through its suppression of a plating defect due to the genetic loss of a major catalase. We show that successful suppression can be achieved only when AhpC is produced in a dose- and time-dependent manner through a complex mechanism involving activation of the transcriptional regulator OxyR, transcription attenuation, and translation reduction. By analyzing AhpC truncation variants, we demonstrate that reactivity with organic peroxides (OPs) rather than H2O2 is resilient to mutagenesis, implying that OP reduction is the core catalytic function of AhpC. Intact AhpC could be recycled only by its cognate reductase AhpF, and AhpC variants lacking the Prx domain or the extreme C-terminal five residues became promiscuous electron acceptors from the thioredoxin reductase TrxR and the GSH reductase Gor in addition to AhpF, implicating an additional dimension to functional plasticity of AhpC. Finally, we show that the activity of S. oneidensis AhpC is less affected by mutations than that of its Escherichia coli counterpart. These findings suggest that the physiological roles of bacterial AhpCs are adapted to different oxidative challenges, depending on the organism, and that its functional plasticity is even more extensive than previously reported.
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Affiliation(s)
- Xue Feng
- Institute of Microbiology, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, China
| | - Kailun Guo
- Institute of Microbiology, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, China
| | - Haichun Gao
- Institute of Microbiology, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, China
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Liang H, Zhang Y, Wang S, Gao H. Mutual interplay between ArcA and σ E orchestrates envelope stress response in Shewanella oneidensis. Environ Microbiol 2020; 23:652-668. [PMID: 32372525 DOI: 10.1111/1462-2920.15060] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2019] [Accepted: 05/03/2020] [Indexed: 01/15/2023]
Abstract
To survive and thrive in harsh and ever-changing environments, intricate mechanisms have evolved for bacterial cells to monitor perturbations impacting the integrity of their envelope and to mount an appropriate response to contain or repair the damage. In this study, we report in Shewanella oneidensis a previously undescribed mechanism for the envelope defect resulting from the loss of Arc, a two-component transcriptional regulatory system crucial for respiration. We uncovered σE , a master regulator establishing and maintaining the integrity of the cell envelope in γ-proteobacteria, as the determining factor for the cell envelope defect of the arcA mutant. When ArcA is depleted, σE activity is compromised by enhanced production of anti-σE protein RseA. Surprisingly, S. oneidensis σE is not essential for viability, but becomes so in the absence of ArcA. Furthermore, we demonstrated that there is an interplay between these two regulators as arcA expression is affected by availability of σE . Overall, our results underscore functional interplay of regulatory systems for envelope stress response: although each of the systems may respond to perturbation of particular components of the envelope, they are functionally intertwined, working together to form an interconnected safety net.
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Affiliation(s)
- Huihui Liang
- Institute of Microbiology and College of Life Sciences, Zhejiang University, Zhejiang, Hangzhou, 310058, China
| | - Yongting Zhang
- Institute of Microbiology and College of Life Sciences, Zhejiang University, Zhejiang, Hangzhou, 310058, China
| | - Sijing Wang
- Institute of Microbiology and College of Life Sciences, Zhejiang University, Zhejiang, Hangzhou, 310058, China
| | - Haichun Gao
- Institute of Microbiology and College of Life Sciences, Zhejiang University, Zhejiang, Hangzhou, 310058, China
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Nitrite modulates aminoglycoside tolerance by inhibiting cytochrome heme-copper oxidase in bacteria. Commun Biol 2020; 3:269. [PMID: 32461576 PMCID: PMC7253457 DOI: 10.1038/s42003-020-0991-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Accepted: 05/05/2020] [Indexed: 01/23/2023] Open
Abstract
As a bacteriostatic agent, nitrite has been used in food preservation for centuries. When used in combination with antibiotics, nitrite is reported to work either cooperatively or antagonistically. However, the mechanism underlying these effects remains largely unknown. Here we show that nitrite mediates tolerance to aminoglycosides in both Gram-negative and Gram-positive bacteria, but has little interaction with other types of antibiotics. Nitrite directly and mainly inhibits cytochrome heme-copper oxidases (HCOs), and by doing so, the membrane potential is compromised, blocking uptake of aminoglycosides. In contrast, reduced respiration (oxygen consumption rate) resulting from nitrite inhibition is not critical for aminoglycoside tolerance. While our data indicate that nitrite is a promising antimicrobial agent targeting HCOs, cautions should be taken when used with other antibiotics, aminoglycosides in particular.
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Promiscuous Enzymes Cause Biosynthesis of Diverse Siderophores in Shewanella oneidensis. Appl Environ Microbiol 2020; 86:AEM.00030-20. [PMID: 32005730 DOI: 10.1128/aem.00030-20] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2020] [Accepted: 01/23/2020] [Indexed: 02/05/2023] Open
Abstract
The siderophore synthetic system in Shewanella species is able to synthesize dozens of macrocyclic siderophores in vitro with synthetic precursors. In vivo, however, although three siderophores are produced naturally in Shewanella algae B516, which carries a lysine decarboxylase (AvbA) specific for siderophore synthesis, only one siderophore can be detected from many other Shewanella species. In this study, we examined a siderophore-overproducing mutant of Shewanella oneidensis which lacks an AvbA counterpart, and we found that it can also produce these three siderophores. We identified both SpeC and SpeF as promiscuous decarboxylases for both lysine and ornithine to synthesize the siderophore precursors cadaverine and putrescine, respectively. Intriguingly, putrescine is mainly synthesized from arginine through an arginine decarboxylation pathway in a constitutive manner, not liable to the concentrations of iron and siderophores. Our results provide further evidence that the substrate availability plays a determining role in siderophore production. Furthermore, we provide evidence to suggest that under iron starvation conditions, cells allocate more putrescine for siderophore biosynthesis by downregulating the expression of the enzyme that transforms putrescine into spermidine. Overall, this study provides another example of the great flexibility of bacterial metabolism that is honed by evolution to better fit living environments of these bacteria.IMPORTANCE The simultaneous production of multiple siderophores is considered a general strategy for microorganisms to rapidly adapt to their ever-changing environments. In this study, we show that some Shewanella spp. may downscale their capability for siderophore synthesis to facilitate adaptation. Although S. oneidensis lacks an enzyme specifically synthesizing cadaverine, it can produce it by using promiscuous ornithine decarboxylases. Despite this ability, this bacterium predominately produces the primary siderophore while restraining the production of secondary siderophores by regulating substrate availability. In addition to using the arginine decarboxylase (ADC) pathway for putrescine synthesis, cells optimize the putrescine pool for siderophore production. Our work provides an insight into the coordinated synthesis of multiple siderophores by harnessing promiscuous enzymes in bacteria and underscores the importance of substrate pools for the biosynthesis of natural products.
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Regulation and Maturation of the Shewanella oneidensis Sulfite Reductase SirA. Sci Rep 2020; 10:953. [PMID: 31969587 PMCID: PMC6976685 DOI: 10.1038/s41598-020-57587-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Accepted: 12/27/2019] [Indexed: 01/12/2023] Open
Abstract
Shewanella oneidensis, a metal reducer and facultative anaerobe, expresses a large number of c-type cytochromes, many of which function as anaerobic reductases. All of these proteins contain the typical heme-binding motif CXXCH and require the Ccm proteins for maturation. Two c-type cytochrome reductases also possess atypical heme-binding sites, the NrfA nitrite reductase (CXXCK) and the SirA sulfite reductase (CX12NKGCH). S. oneidensis MR-1 encodes two cytochrome c synthetases (CcmF and SirE) and two apocytochrome c chaperones (CcmI and SirG). SirE located in the sir gene cluster is required for the maturation of SirA, but not NrfA. Here we show that maturation of SirA requires the combined function of the two apocytochrome c chaperones CcmI and SirG. Loss of either protein resulted in decreased sulfite reductase. Furthermore, SirA was not detected in a mutant that lacked both chaperones, perhaps due to misfolding or instability. These results suggest that CcmI interacts with SirEFG during SirA maturation, and with CcmF during maturation of NrfA. Additionally, we show that CRP regulates expression of sirA via the newly identified transcriptional regulatory protein, SirR.
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Su L, Fukushima T, Prior A, Baruch M, Zajdel TJ, Ajo-Franklin CM. Modifying Cytochrome c Maturation Can Increase the Bioelectronic Performance of Engineered Escherichia coli. ACS Synth Biol 2020; 9:115-124. [PMID: 31880923 DOI: 10.1021/acssynbio.9b00379] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Genetic circuits that encode extracellular electron transfer (EET) pathways allow the intracellular state of Escherichia coli to be electronically monitored and controlled. However, relatively low electron flux flows through these pathways, limiting the degree of control by these circuits. Since the EET pathway is composed of multiple multiheme cytochromes c (cyts c) from Shewanella oneidensis MR-1, we hypothesized that lower expression levels of cyt c may explain this low EET flux and may be caused by the differences in the cyt c maturation (ccm) machinery between these two species. Here, we constructed random mutations within ccmH by error-prone PCR and screened for increased cyt c production. We identified two ccmH mutants, ccmH-132 and ccmH-195, that exhibited increased heterologous cyt c expression, but had different effects on EET. The ccmH-132 strain reduced WO3 nanoparticles faster than the parental control, whereas the ccmH-195 strain reduced more slowly. The same trend is reflected in electrical current generation: ccmH-132, which has only a single mutation from WT, drastically increased current production by 77%. The percentage of different cyt c proteins in these two mutants suggests that the stoichiometry of the S. oneidensis cyts c is a key determinant of current production by Mtr-expressing E. coli. Thus, we conclude that modulating cyt c maturation effectively improves genetic circuits governing EET in engineered biological systems, enabling better bioelectronic control of E. coli.
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Affiliation(s)
- Lin Su
- State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, Southeast University, Nanjing, 210018, China
- Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Tatsuya Fukushima
- Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Andrew Prior
- Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Moshe Baruch
- Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Tom J. Zajdel
- Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Caroline M. Ajo-Franklin
- Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
- Molecular Biophysics and Integrated Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
- Synthetic Biology Institute, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
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Wang F, Wang Y, Cen C, Fu L, Wang Y. A tandem GGDEF-EAL domain protein-regulated c-di-GMP signal contributes to spoilage-related activities of Shewanella baltica OS155. Appl Microbiol Biotechnol 2020; 104:2205-2216. [PMID: 31927761 DOI: 10.1007/s00253-020-10357-w] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Revised: 12/23/2019] [Accepted: 01/05/2020] [Indexed: 11/26/2022]
Abstract
Cyclic diguanylate (c-di-GMP) is a second messenger involved in the regulation of various physiological processes in bacteria. However, its function in spoilage bacteria has not yet been addressed. Here, we studied the function of a tandem GGDEF-EAL domain protein, Sbal_3235, in the spoilage bacterium Shewanella baltica OS155. The deletion of sbal_3235 significantly reduced the c-di-GMP level, biofilm formation, and exopolysaccharide, trimethylamine (TMA), and putrescine production; sbal_3235 deletion also downregulated the expression of the torS and speF genes and affected membrane fatty acid composition. Site-directed mutagenesis in conserved GGDEF and EAL motifs abolished diguanylate cyclase (DGC) and phosphodiesterase (PDE) activity, respectively. These data indicate that Sbal_3235 is an essential contributor to the c-di-GMP pool with bifunctional DGC and PDE activity, which is involved in the biofilm formation and spoilage activity of S. baltica OS155. Our findings expand the biochemical role of c-di-GMP and uncover its link to spoilage activities, providing novel targets for food quality and safety controlling.
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Affiliation(s)
- Feifei Wang
- Food Safety Key Laboratory of Zhejiang Province, School of Food Science and Biotechnology, Zhejiang Gongshang University, Hangzhou, 310018, People's Republic of China
| | - Yongzheng Wang
- Food Safety Key Laboratory of Zhejiang Province, School of Food Science and Biotechnology, Zhejiang Gongshang University, Hangzhou, 310018, People's Republic of China
| | - Congnan Cen
- Food Safety Key Laboratory of Zhejiang Province, School of Food Science and Biotechnology, Zhejiang Gongshang University, Hangzhou, 310018, People's Republic of China
| | - Linglin Fu
- Food Safety Key Laboratory of Zhejiang Province, School of Food Science and Biotechnology, Zhejiang Gongshang University, Hangzhou, 310018, People's Republic of China.
- Zhejiang Engineering Institute of Food Quality and Safety, Zhejiang Gongshang University, Hangzhou, 310018, People's Republic of China.
| | - Yanbo Wang
- Food Safety Key Laboratory of Zhejiang Province, School of Food Science and Biotechnology, Zhejiang Gongshang University, Hangzhou, 310018, People's Republic of China.
- Zhejiang Engineering Institute of Food Quality and Safety, Zhejiang Gongshang University, Hangzhou, 310018, People's Republic of China.
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Complex Oxidation of Apocytochromes c during Bacterial Cytochrome c Maturation. Appl Environ Microbiol 2019; 85:AEM.01989-19. [PMID: 31585997 DOI: 10.1128/aem.01989-19] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2019] [Accepted: 09/30/2019] [Indexed: 12/22/2022] Open
Abstract
c-Type cytochromes (cyts c) are proteins that contain covalently bound heme and that thus require posttranslational modification for activity, a process carried out by the cytochrome c (cyt c) maturation system (referred to as the Ccm system) in many Gram-negative bacteria. It has been established that during cyt c maturation (CCM), two cysteine thiols of the heme binding motif (CXXCH) within apocytochromes c (apocyts c) are first oxidized largely by DsbA to form a disulfide bond, which is later reduced through a thio-reductive pathway involving DsbD. However, the physiological impacts of DsbA proteins on CCM in fact vary significantly among bacteria. In this work, we used the cyt c-rich Gram-negative bacterium Shewanella oneidensis as the research model to clarify the roles of DsbA proteins in CCM. We show that in terms of the oxidation of apocyts c, DsbA proteins are an important but not critical factor, and, strikingly, oxygen is not either. By exploiting the DsbD-independent pathway, we identify DsbA1, DsbA2, and DsbA3 as oxidants contributing to the oxidation of apocyts c and reductants, such as cysteine, to be an effective antagonist against DsbA-independent oxidation. We further show that DsbB proteins are partially responsible for the reoxidization of reduced DsbA proteins. Overall, our results indicate that the DsbA-DsbB redox pair has a limited role in CCM, challenging the established notion that it is the main oxidant for apocyts c IMPORTANCE DsbA is a powerful oxidase that functions in the bacterial periplasm to introduce disulfide bonds in many proteins, including apocytochromes c It has been well established that although DsbA is not essential, it plays a primary role in cytochrome c maturation, based on studies in bacteria hosting several cyts c Here, with cyt c-rich S. oneidensis as a research model, we show that this is not always the case. Moreover, we demonstrate that DsbB is also not essential for cytochrome c maturation. These results underscore the need to identify oxidants other than DsbA/DsbB that are crucial in the oxidation of apocyts c in bacteria.
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Sun Y, Meng Q, Zhang Y, Gao H. Derepression of bkd by the FadR loss dictates elevated production of BCFAs and isoleucine starvation. Biochim Biophys Acta Mol Cell Biol Lipids 2019; 1865:158577. [PMID: 31759173 DOI: 10.1016/j.bbalip.2019.158577] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2019] [Accepted: 11/13/2019] [Indexed: 12/21/2022]
Abstract
In many γ-proteobacteria, FadR is recognized as a global transcriptional regulator: in addition to being the most prominent regulator for FA biosynthesis and degradation, the protein also mediates expression of many genes in diverse biological processes. In Shewanella oneidensis, a bacterium renowned for its respiratory versatility, FadR directly controls only a few genes. However, the FadR loss substantially increases BCFA contents and impairs growth. In this study, we showed that FadR is required to activate a number of important FA biosynthesis genes, including fabA, fabB, and fabH1. Although most of these genes are controlled by FadR in a direct manner, they are not critically responsible for the phenotypes resulting from the FadR depletion. Subsequent investigations identified BKD encoded by the bkd operon as the critical factor for enhanced BCFA production. In the absence of FadR, the bkd operon is derepressed, resulting in elevated conversion of 3MOP to 3-methylbutanoyl-CoA, one of the direct substrates for BCFA synthesis. We further showed that the growth defect of the fadR mutant is due to BCAA shortage, a scenario also attributable to excessive BKD: 3MOP, the common substrate for both BCFA and BCAA, is disproportionately used for BCFA synthesis, leading to reduced production of BCAA. Collectively, our findings reveal that the S. oneidensis FadR regulon is surely larger than previously proposed and a new mechanism by which FadR impacts bacterial physiology.
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Affiliation(s)
- Yijuan Sun
- Institute of Microbiology College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Qiu Meng
- Institute of Microbiology College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang 310058, China; College of Biotechnology and Bioengineering, Zhejiang University of Technology, 18 Chaowang Rd, Hangzhou, 310014, Zhejiang, China
| | - Yongting Zhang
- Institute of Microbiology College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Haichun Gao
- Institute of Microbiology College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang 310058, China.
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Wu G, Jin F. Pellicle development of Shewanella oneidensis is an aerotaxis-piloted and energy-dependent process. Biochem Biophys Res Commun 2019; 519:127-133. [PMID: 31481239 DOI: 10.1016/j.bbrc.2019.08.144] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2019] [Accepted: 08/26/2019] [Indexed: 11/19/2022]
Abstract
Pellicles are biofilms found at the air-liquid interface and are widely distributed in natural environments. In this study, a simple pellicle detection method was established, and using this new method, the pellicle formation activities of Shewanella oneidensis MR-1 and its 42 cytochrome c mutants were analysed. The results showed that the pellicle was initiated at very early stages of incubation. Aerotaxis was the major external factor, while energy acquirement was the main internal factor for pellicle initiation. Among the 42 cytochrome c mutants, 17 mutants, including those deficient in aerobic respiration, sulfur or sulfite/sulfate respiration, nitrite respiration, metal respiration, DMSO respiration and fumarate respiration, exhibited delayed pellicle initiation. The results suggest that S. oneidensis utilizes the electron acceptors simultaneously under anoxic conditions and that the disruption of any of these anaerobic respiration routes would retard pellicle initiation.
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Affiliation(s)
- Genfu Wu
- College of Life Sciences, Zhejiang University, Hangzhou, 310058, China.
| | - Feifei Jin
- College of Life Sciences, Zhejiang University, Hangzhou, 310058, China
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Distinct Roles of Shewanella oneidensis Thioredoxin in Regulation of Cellular Responses to Hydrogen and Organic Peroxides. Appl Environ Microbiol 2019; 85:AEM.01700-19. [PMID: 31444207 DOI: 10.1128/aem.01700-19] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2019] [Accepted: 08/21/2019] [Indexed: 12/26/2022] Open
Abstract
The thioredoxin (Trx) and glutaredoxin (Grx) antioxidant systems are deeply involved in bacterial response to oxidative stress, but to date, we know surprisingly little about the roles of these systems in response to reactive oxygen species (ROS) other than hydrogen peroxide (H2O2). In this study, we used Shewanella oneidensis, an environmental bacterium, as a research model to investigate the roles of Trx and Grx in oxidative stress response because it has functionally intertwined ROS responsive regulators OxyR and OhrR. We found that Trx1 is the major thiol/disulfide redox system and that in its absence a Grx system becomes essential under normal conditions. Although overshadowed by Trx1 in the wild type, Trx2 can fully replace Trx1 in physiology when overproduced. Trx1 is required for OxyR to function as a repressor but, more importantly, plays a critical role in the cellular response to organic peroxide (OP) by mediating the redox status of OhrR but not OP scavenger OhrA. While none of the trx and grx genes are OxyR dependent, trxA and trxC are affected by OhrR indirectly. Additional data suggest that depletion of glutathione is likely the cue to trigger induced expression of trxA and trxC These findings underscore the particular importance of Trx in the bacterial OP stress response.IMPORTANCE The Trx and Grx systems are deeply involved in bacterial responses to H2O2-induced oxidative stress. However, little is known about their roles in response to other ROS, such as organic peroxides (OPs). In this study, we used S. oneidensis as a research model to investigate the interplay between Trx/Grx and OxyR/OhrR. We show that Trxs mediate the redox status of transcriptional OP-responding regulator OhrR. Although none of the trx or grx genes are directly controlled by OxyR or OhrR, expression of trxA and trxC is induced by tert-butyl hydroperoxide (t-BHP). We further show that the trxA and trxC genes respond to effects of glutathione (GSH) depletion rather than oxidation. These findings underscore the particular importance of Trx in the bacterial OP stress response.
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Liang H, Mao Y, Sun Y, Gao H. Transcriptional regulator ArcA mediates expression of oligopeptide transport systems both directly and indirectly in Shewanella oneidensis. Sci Rep 2019; 9:13839. [PMID: 31554843 PMCID: PMC6761289 DOI: 10.1038/s41598-019-50201-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2019] [Accepted: 09/09/2019] [Indexed: 11/09/2022] Open
Abstract
In γ-proteobacterial species, such as Escherichia coli, the Arc (anoxic redox control) two-component system plays a major role in mediating the metabolic transition from aerobiosis to anaerobiosis, and thus is crucial for anaerobic growth but dispensable for aerobic growth. In Shewanella oneidensis, a bacterium renowned for respiratory versatility, Arc (SoArc) primarily affects aerobic growth. To date, how this occurs has remained largely unknown although the growth defect resulting from the loss of DNA-binding response regulator SoArcA is tryptone-dependent. In this study, we demonstrated that the growth defect is in part linked to utilization of oligopeptides and di-tripeptides, and peptide uptake but not peptide degradation is significantly affected by the SoArcA loss. A systematic characterization of major small peptide uptake systems manifests that ABC peptide transporter Sap and four proton-dependent oligopeptide transporters (POTs) are responsible for transport of oligopeptides and di-tripeptides respectively. Among them, Sap and DtpA (one of POTs) are responsive to the SoarcA mutation but only dtpA is under the direct control of SoArcA. We further showed that both Sap and DtpA, when overproduced, improve growth of the SoarcA mutant. While the data firmly establish a link between transport of oligopeptides and di-tripeptides and the SoarcA mutation, other yet-unidentified factors are implicated in the growth defect resulting from the SoArcA loss.
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Affiliation(s)
- Huihui Liang
- Institute of Microbiology, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, 310058, China
| | - Yinting Mao
- Institute of Microbiology, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, 310058, China
| | - Yijuan Sun
- Institute of Microbiology, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, 310058, China.,Research Center of Siyuan Natural Pharmacy and Biotoxicology, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, 310058, China
| | - Haichun Gao
- Institute of Microbiology, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, 310058, China. .,Research Center of Siyuan Natural Pharmacy and Biotoxicology, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, 310058, China.
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Yu Z, Yu D, Mao Y, Zhang M, Ding M, Zhang J, Wu S, Qiu J, Yin J. Identification and characterization of a LuxI/R-type quorum sensing system in Pseudoalteromonas. Res Microbiol 2019; 170:243-255. [DOI: 10.1016/j.resmic.2019.07.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Revised: 07/04/2019] [Accepted: 07/09/2019] [Indexed: 12/30/2022]
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Liu X, Tang K, Zhang D, Li Y, Liu Z, Yao J, Wood TK, Wang X. Symbiosis of a P2‐family phage and deep‐sea
Shewanella putrefaciens. Environ Microbiol 2019; 21:4212-4232. [DOI: 10.1111/1462-2920.14781] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2019] [Revised: 07/12/2019] [Accepted: 08/13/2019] [Indexed: 11/30/2022]
Affiliation(s)
- Xiaoxiao Liu
- Key Laboratory of Tropical Marine Bio‐resources and Ecology, Guangdong Key Laboratory of Marine Materia Medica RNAM Center for Marine Microbiology, South China Sea Institute of Oceanology, Chinese Academy of Sciences Guangzhou 510301 China
| | - Kaihao Tang
- Key Laboratory of Tropical Marine Bio‐resources and Ecology, Guangdong Key Laboratory of Marine Materia Medica RNAM Center for Marine Microbiology, South China Sea Institute of Oceanology, Chinese Academy of Sciences Guangzhou 510301 China
| | - Dali Zhang
- Key Laboratory of Tropical Marine Bio‐resources and Ecology, Guangdong Key Laboratory of Marine Materia Medica RNAM Center for Marine Microbiology, South China Sea Institute of Oceanology, Chinese Academy of Sciences Guangzhou 510301 China
| | - Yangmei Li
- Key Laboratory of Tropical Marine Bio‐resources and Ecology, Guangdong Key Laboratory of Marine Materia Medica RNAM Center for Marine Microbiology, South China Sea Institute of Oceanology, Chinese Academy of Sciences Guangzhou 510301 China
- University of Chinese Academy of Sciences Beijing 100049 China
| | - Zhe Liu
- Guangdong Provincial Center for Disease Control and Prevention Guangdong Provincial Institute of Public Health Guangzhou 511430 China
| | - Jianyun Yao
- Key Laboratory of Tropical Marine Bio‐resources and Ecology, Guangdong Key Laboratory of Marine Materia Medica RNAM Center for Marine Microbiology, South China Sea Institute of Oceanology, Chinese Academy of Sciences Guangzhou 510301 China
| | - Thomas K. Wood
- Department of Chemical Engineering Pennsylvania State University University Park PA 16802‐4400 USA
| | - Xiaoxue Wang
- Key Laboratory of Tropical Marine Bio‐resources and Ecology, Guangdong Key Laboratory of Marine Materia Medica RNAM Center for Marine Microbiology, South China Sea Institute of Oceanology, Chinese Academy of Sciences Guangzhou 510301 China
- University of Chinese Academy of Sciences Beijing 100049 China
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Adaptive Responses of Shewanella decolorationis to Toxic Organic Extracellular Electron Acceptor Azo Dyes in Anaerobic Respiration. Appl Environ Microbiol 2019; 85:AEM.00550-19. [PMID: 31175185 DOI: 10.1128/aem.00550-19] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2019] [Accepted: 05/29/2019] [Indexed: 12/18/2022] Open
Abstract
Bacterial anaerobic respiration using an extracellular electron acceptor plays a predominant role in global biogeochemical cycles. However, the mechanisms of bacterial adaptation to the toxic organic pollutant as the extracellular electron acceptor during anaerobic respiration are not clear, which limits our ability to optimize the strategies for the bioremediation of a contaminated environment. Here, we report the physiological characteristics and the global gene expression of an ecologically successful bacterium, Shewanella decolorationis S12, when using a typical toxic organic pollutant, amaranth, as the extracellular electron acceptor. Our results revealed that filamentous shift (the cells stretched to fiber-like shapes as long as 18 μm) occurred under amaranth stress. Persistent stress led to a higher filamentous cell rate and decolorization ability in subcultural cells compared to parental strains. In addition, the expression of genes involved in cell division, the chemotaxis system, energy conservation, damage repair, and material transport in filamentous cells was significantly stimulated. The detailed roles of some genes with significantly elevated expressions in filamentous cells, such as the outer membrane porin genes ompA and ompW, the cytochrome c genes arpC and arpD, the global regulatory factor gene rpoS, and the methyl-accepting chemotaxis proteins genes SHD_2793 and SHD_0015, were identified by site-directed mutagenesis. Finally, a conceptual model was proposed to help deepen our insights into both the bacterial survival strategy when toxic organics were present and the mechanisms by which these toxic organics were biodegraded as the extracellular electron acceptors.IMPORTANCE Keeping toxic organic pollutants (TOPs) in tolerable levels is a huge challenge for bacteria in extremely unfavorable environments since TOPs could serve as energy substitutes but also as survival stresses when they are beyond some thresholds. This study focused on the underlying adaptive mechanisms of ecologically successful bacterium Shewanella decolorationis S12 when exposed to amaranth, a typical toxic organic pollutant, as the extracellular electron acceptor. Our results suggest that filamentous shift is a flexible and valid way to solve the dilemma between the energy resource and toxic stress. Filamentous cells regulate gene expression to enhance their degradation and detoxification capabilities, resulting in a strong viability. These novel adaptive responses to TOPs are believed to be an evolutionary achievement to succeed in harsh habitats and thus have great potential to be applied to environment engineering or synthetic biology if we could picture every unknown node in this pathway.
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