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Li L, Li Q, Xiao Y, Ma J, Liu GQ. H-NS involved in positive regulation of glycerol dehydratase gene expression in Klebsiella pneumoniae 2e. Appl Environ Microbiol 2024; 90:e0007524. [PMID: 38995045 PMCID: PMC11337852 DOI: 10.1128/aem.00075-24] [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: 01/14/2024] [Accepted: 06/13/2024] [Indexed: 07/13/2024] Open
Abstract
Glycerol dehydratase is the key and rate-limiting enzyme in the 1,3-propanediol synthesis pathway of Klebsiella pneumoniae, which determined the producing rate and yield of 1,3-propanediol. However, the expression regulation mechanism of glycerol dehydratase gene dhaB remains poorly unknown. In this study, a histone-like nucleoid-structuring (H-NS) protein was identified and characterized as the positive transcription regulator for dhaB expression in K. pneumoniae 2e, which exhibited high tolerance against crude glycerol in our previous study. Deletion of hns gene significantly decreased the transcription level of dhaB in K. pneumoniae 2e, which led to a remarkable defect on strain growth, glycerol dehydratase activity, and 3-hydroxypropanal production during glycerol fermentation. The transcription level of dhaB was significantly up-regulated in crude glycerol relative to pure glycerol, while the inactivation of H-NS resulted in more negative effect for transcription level of dhaB in the former. Though the H-NS expression level was almost comparable in both substrates, its multimer state was reduced in crude glycerol relative to pure glycerol, suggesting that the oligomerization state of H-NS might have contributed for positive regulation of dhaB expression. Furthermore, electrophoretic mobility shift and DNase I footprinting assays showed that H-NS could directly bind to the upstream promoter region of dhaB by recognizing the AT-rich region. These findings provided new insight into the transcriptional regulation mechanism of H-NS for glycerol dehydratase expression in K. pneumoniae, which might offer new target for engineering bacteria to industrially produce 1,3-propanediol.IMPORTANCEThe biological production of 1,3-propanediol from glycerol by microbial fermentation shows great promising prospect on industrial application. Glycerol dehydratase catalyzes the penultimate step in glycerol metabolism and is regarded as one of the key and rate-limiting enzymes for 1,3-propanediol production. H-NS was reported as a pleiotropic modulator with negative effects on gene expression in most studies. Here, we reported for the first time that the expression of glycerol dehydratase gene is positively regulated by the H-NS. The results provide insight into a novel molecular mechanism of H-NS for positive regulation of glycerol dehydratase gene expression in K. pneumoniae, which holds promising potential for facilitating construction of engineering highly efficient 1,3-propanediol-producing strains.
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Affiliation(s)
- Le Li
- International Cooperation Base of Science and Technology Innovation on Forest Resource Biotechnology, Central South University of Forestry and Technology, Changsha, China
- Hunan Provincial Key Laboratory of Forestry Biotechnology, Central South University of Forestry and Technology, Changsha, China
- Economic Forest Variety Creation Center, Yuelushan National Laboratory of Seed Industry, Changsha, China
| | - Qiang Li
- International Cooperation Base of Science and Technology Innovation on Forest Resource Biotechnology, Central South University of Forestry and Technology, Changsha, China
- Hunan Provincial Key Laboratory of Forestry Biotechnology, Central South University of Forestry and Technology, Changsha, China
- Economic Forest Variety Creation Center, Yuelushan National Laboratory of Seed Industry, Changsha, China
| | - Yuting Xiao
- International Cooperation Base of Science and Technology Innovation on Forest Resource Biotechnology, Central South University of Forestry and Technology, Changsha, China
- Hunan Provincial Key Laboratory of Forestry Biotechnology, Central South University of Forestry and Technology, Changsha, China
- Economic Forest Variety Creation Center, Yuelushan National Laboratory of Seed Industry, Changsha, China
| | - Jiangshan Ma
- International Cooperation Base of Science and Technology Innovation on Forest Resource Biotechnology, Central South University of Forestry and Technology, Changsha, China
- Hunan Provincial Key Laboratory of Forestry Biotechnology, Central South University of Forestry and Technology, Changsha, China
- Economic Forest Variety Creation Center, Yuelushan National Laboratory of Seed Industry, Changsha, China
| | - Gao-Qiang Liu
- International Cooperation Base of Science and Technology Innovation on Forest Resource Biotechnology, Central South University of Forestry and Technology, Changsha, China
- Hunan Provincial Key Laboratory of Forestry Biotechnology, Central South University of Forestry and Technology, Changsha, China
- Economic Forest Variety Creation Center, Yuelushan National Laboratory of Seed Industry, Changsha, China
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2
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Qiu X, Hu XM, Tang XX, Huang CH, Jian HH, Lin DH. Metabolic adaptations of Microbacterium sediminis YLB-01 in deep-sea high-pressure environments. Appl Microbiol Biotechnol 2024; 108:170. [PMID: 38265689 DOI: 10.1007/s00253-023-12906-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2023] [Revised: 10/30/2023] [Accepted: 11/07/2023] [Indexed: 01/25/2024]
Abstract
The deep-sea environment is an extremely difficult habitat for microorganisms to survive in due to its intense hydrostatic pressure. However, the mechanisms by which these organisms adapt to such extreme conditions remain poorly understood. In this study, we investigated the metabolic adaptations of Microbacterium sediminis YLB-01, a cold and stress-tolerant microorganism isolated from deep-sea sediments, in response to high-pressure conditions. YLB-01 cells were cultured at normal atmospheric pressure and 28 ℃ until they reached the stationary growth phase. Subsequently, the cells were exposed to either normal pressure or high pressure (30 MPa) at 4 ℃ for 7 days. Using NMR-based metabolomic and proteomic analyses of YLB-01 cells exposed to high-pressure conditions, we observed significant metabolic changes in several metabolic pathways, including amino acid, carbohydrate, and lipid metabolism. In particular, the high-pressure treatment stimulates cell division and triggers the accumulation of UDP-glucose, a critical factor in cell wall formation. This finding highlights the adaptive strategies used by YLB-01 cells to survive in the challenging high-pressure environments of the deep sea. Specifically, we discovered that YLB-01 cells regulate amino acid metabolism, promote carbohydrate metabolism, enhance cell wall synthesis, and improve cell membrane fluidity in response to high pressure. These adaptive mechanisms play essential roles in supporting the survival and growth of YLB-01 in high-pressure conditions. Our study offers valuable insights into the molecular mechanisms underlying the metabolic adaptation of deep-sea microorganisms to high-pressure environments. KEY POINTS: • NMR-based metabolomic and proteomic analyses were conducted on Microbacterium sediminis YLB-01 to investigate the significant alterations in several metabolic pathways in response to high-pressure treatment. • YLB-01 cells used adaptive strategies (such as regulated amino acid metabolism, promoted carbohydrate metabolism, enhanced cell wall synthesis, and improved cell membrane fluidity) to survive in the challenging high-pressure environment of the deep sea. • High-pressure treatment stimulated cell division and triggered the accumulation of UDP-glucose, a critical factor in cell wall formation, in Microbacterium sediminis YLB-01 cells.
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Affiliation(s)
- Xu Qiu
- Key Laboratory for Chemical Biology of Fujian Province, MOE Key Laboratory of Spectrochemical Analysis and Instrumentation, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, China
| | - Xiao-Min Hu
- Key Laboratory for Chemical Biology of Fujian Province, MOE Key Laboratory of Spectrochemical Analysis and Instrumentation, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, China
| | - Xi-Xiang Tang
- State Key Laboratory Breeding Base of Marine Genetic Resources, Key Laboratory of Marine Genetic Resources, Fujian Key Laboratory of Marine Genetic Resources, Third Institute of Oceanography, Ministry of Natural Resources, Xiamen, China.
| | - Cai-Hua Huang
- Research and Communication Center of Exercise and Health, Xiamen University of Technology, Xiamen, China
| | - Hua-Hua Jian
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Dong-Hai Lin
- Key Laboratory for Chemical Biology of Fujian Province, MOE Key Laboratory of Spectrochemical Analysis and Instrumentation, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, China.
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3
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Cai W, Tang F, Jiang L, Li R, Wang Z, Liu Y. Histone-Like Nucleoid Structuring Protein Modulates the Fitness of tet(X4)-Bearing IncX1 Plasmids in Gram-Negative Bacteria. Front Microbiol 2021; 12:763288. [PMID: 34858374 PMCID: PMC8632487 DOI: 10.3389/fmicb.2021.763288] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Accepted: 10/14/2021] [Indexed: 11/13/2022] Open
Abstract
The emergence of plasmid-mediated tigecycline resistance gene tet(X4) poses a challenging threat to public health. Based on the analysis of tet(X4)-positive plasmids in the NCBI database, we found that the IncX1-type plasmid is one of the most common vectors for spreading tet(X4) gene, but the mechanisms by which these plasmids adapt to host bacteria and maintain the persistence of antibiotic resistance genes (ARGs) remain unclear. Herein, we investigated the underlying mechanisms of how host bacteria modulate the fitness cost of IncX1 plasmids carrying tet(X4) gene. Interestingly, we found that the tet(X4)-bearing IncX1 plasmids encoding H-NS protein imposed low or no fitness cost in Escherichia coli and Klebsiella pneumoniae; instead, they partially promoted the virulence and biofilm formation in host bacteria. Regression analysis revealed that the expression of hns gene in plasmids was positively linked to the relative fitness of host bacteria. Furthermore, when pCE2::hns was introduced, the fitness of tet(X4)-positive IncX1 plasmid pRF55-1 without hns gene was significantly improved, indicating that hns mediates the improvement of fitness. Finally, we showed that the expression of hns gene is negatively correlated with the expression of tet(X4) gene, suggesting that the regulatory effect of H-NS on adaptability may be attributed to its inhibitory effect on the expression of ARGs. Together, our findings suggest the important role of plasmid-encoded H-NS protein in modulating the fitness of tet(X4)-bearing IncX1 plasmids, which shed new insight into the dissemination of tet(X4) gene in a biological environment.
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Affiliation(s)
- Wenhui Cai
- College of Veterinary Medicine, Yangzhou University, Yangzhou, China
| | - Feifei Tang
- College of Veterinary Medicine, Yangzhou University, Yangzhou, China
| | - Lijie Jiang
- College of Veterinary Medicine, Yangzhou University, Yangzhou, China
| | - Ruichao Li
- College of Veterinary Medicine, Yangzhou University, Yangzhou, China.,Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, China.,Joint International Research Laboratory of Agriculture and Agri-Product Safety, The Ministry of Education of China, Yangzhou University, Yangzhou, China.,Institute of Comparative Medicine, Yangzhou University, Yangzhou, China
| | - Zhiqiang Wang
- College of Veterinary Medicine, Yangzhou University, Yangzhou, China.,Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, China.,Joint International Research Laboratory of Agriculture and Agri-Product Safety, The Ministry of Education of China, Yangzhou University, Yangzhou, China
| | - Yuan Liu
- College of Veterinary Medicine, Yangzhou University, Yangzhou, China.,Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, China.,Joint International Research Laboratory of Agriculture and Agri-Product Safety, The Ministry of Education of China, Yangzhou University, Yangzhou, China.,Institute of Comparative Medicine, Yangzhou University, Yangzhou, China
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4
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Jian H, Xu G, Yi Y, Hao Y, Wang Y, Xiong L, Wang S, Liu S, Meng C, Wang J, Zhang Y, Chen C, Feng X, Luo H, Zhang H, Zhang X, Wang L, Wang Z, Deng Z, Xiao X. The origin and impeded dissemination of the DNA phosphorothioation system in prokaryotes. Nat Commun 2021; 12:6382. [PMID: 34737280 PMCID: PMC8569181 DOI: 10.1038/s41467-021-26636-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2018] [Accepted: 10/18/2021] [Indexed: 12/13/2022] Open
Abstract
Phosphorothioate (PT) modification by the dnd gene cluster is the first identified DNA backbone modification and constitute an epigenetic system with multiple functions, including antioxidant ability, restriction modification, and virus resistance. Despite these advantages for hosting dnd systems, they are surprisingly distributed sporadically among contemporary prokaryotic genomes. To address this ecological paradox, we systematically investigate the occurrence and phylogeny of dnd systems, and they are suggested to have originated in ancient Cyanobacteria after the Great Oxygenation Event. Interestingly, the occurrence of dnd systems and prophages is significantly negatively correlated. Further, we experimentally confirm that PT modification activates the filamentous phage SW1 by altering the binding affinity of repressor and the transcription level of its encoding gene. Competition assays, concurrent epigenomic and transcriptomic sequencing subsequently show that PT modification affects the expression of a variety of metabolic genes, which reduces the competitive fitness of the marine bacterium Shewanella piezotolerans WP3. Our findings strongly suggest that a series of negative effects on microorganisms caused by dnd systems limit horizontal gene transfer, thus leading to their sporadic distribution. Overall, our study reveals putative evolutionary scenario of the dnd system and provides novel insights into the physiological and ecological influences of PT modification.
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Affiliation(s)
- Huahua Jian
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Development Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
- Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai, China
| | - Guanpeng Xu
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Development Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Yi Yi
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Development Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Yali Hao
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Development Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Yinzhao Wang
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Development Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Lei Xiong
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministry of Education, School of Pharmaceutical Sciences, Wuhan University, Wuhan, China
| | - Siyuan Wang
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Development Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Shunzhang Liu
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Development Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Canxing Meng
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Development Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Jiahua Wang
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Development Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Yue Zhang
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Development Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Chao Chen
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministry of Education, School of Pharmaceutical Sciences, Wuhan University, Wuhan, China
| | - Xiaoyuan Feng
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Development Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
- Simon F. S. Li Marine Science Laboratory, School of Life Sciences, The Chinese University of Hong Kong, Hong Kong, China
| | - Haiwei Luo
- Simon F. S. Li Marine Science Laboratory, School of Life Sciences, The Chinese University of Hong Kong, Hong Kong, China
| | - Hao Zhang
- Simon F. S. Li Marine Science Laboratory, School of Life Sciences, The Chinese University of Hong Kong, Hong Kong, China
| | | | - Lianrong Wang
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministry of Education, School of Pharmaceutical Sciences, Wuhan University, Wuhan, China
| | - Zhijun Wang
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Development Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Zixin Deng
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Development Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Xiang Xiao
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Development Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China.
- Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai, China.
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5
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A Histone-Like Nucleoid Structuring Protein Regulates Several Virulence Traits in Burkholderia multivorans. Appl Environ Microbiol 2021; 87:e0036921. [PMID: 33931418 PMCID: PMC8231446 DOI: 10.1128/aem.00369-21] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Burkholderia cepacia complex bacteria comprise opportunistic pathogens causing chronic respiratory infections in cystic fibrosis (CF) patients. These microorganisms produce an exopolysaccharide named cepacian, which is considered a virulence determinant. To find genes implicated in the regulation of cepacian biosynthesis, we characterized an evolved nonmucoid variant (17616nmv) derived from the ancestor, Burkholderia multivorans ATCC 17616, after prolonged stationary phase. Lack of cepacian biosynthesis was correlated with downregulation of the expression of bce genes implicated in its biosynthesis. Furthermore, genome sequencing of the variant identified the transposition of the mobile element IS406 upstream of the coding sequence of an hns-like gene (Bmul_0158) encoding a histone-like nucleoid structuring (H-NS) protein, a known global transcriptional repressor. This insertion sequence (IS) element upregulated the expression of Bmul_0158 by 4-fold. Transcriptome analysis identified the global effects of this mutation on gene expression, with major changes in genes implicated in motility, pilus synthesis, type VI secretion, and chromosome-associated functions. Concomitant with these differences, the nonmucoid variant displays reduced adherence to a CF lung bronchial cell line and reduced surface hydrophobicity and forms smaller cellular aggregates but has an increase in swimming and swarming motilities. Finally, analysis of the GC content of the upstream region of differentially expressed genes led to the identification of various genomic regions, possibly acquired by horizontal gene transfer, which were transcriptionally repressed by the increased expression of the Bmul_0158 gene in the 17616nmv strain. Taken together, the results revealed a significant role for this H-NS protein in the regulation of B. multivorans persistence- and virulence-associated genes. IMPORTANCE Members of the histone-like nucleoid structuring (H-NS) family of proteins, present in many bacteria, are important global regulators of gene expression. Many of the regulated genes were acquired horizontally and include pathogenicity islands and prophages, among others. Additionally, H-NS can play a structural role by bridging and compacting DNA, fulfilling a crucial role in cell physiology. Several virulence phenotypes have been frequently identified in several bacteria as dependent on H-NS activity. Here, we describe an H-NS-like protein of the opportunistic pathogen Burkholderia multivorans, a species commonly infecting the respiratory tract of cystic fibrosis patients. Our results indicate that this protein is involved in regulating virulence traits such as exopolysaccharide biosynthesis, adhesion to biotic surfaces, cellular aggregation, and motility. Furthermore, this H-NS-like protein is one out of eight orthologs present in the B. multivorans ATCC 17616 genome, posing relevant questions to be investigated on how these proteins coordinate the expression of virulence traits.
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Proteomic and Systematic Functional Profiling Unveils Citral Targeting Antibiotic Resistance, Antioxidant Defense, and Biofilm-Associated Two-Component Systems of Acinetobacter baumannii To Encumber Biofilm and Virulence Traits. mSystems 2020; 5:5/6/e00986-20. [PMID: 33203690 PMCID: PMC7677002 DOI: 10.1128/msystems.00986-20] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Acinetobacter baumannii is a nosocomial-infection-causing bacterium and also possesses multidrug resistance to a wide range of conventional antibiotics. The biofilm-forming ability of A. baumannii plays a major role in its resistance and persistence. There is an alarming need for novel treatment strategies to control A. baumannii biofilm-associated issues. The present study demonstrated the strong antibiofilm and antivirulence efficacy of citral against A. baumannii. In addition, proteomic analysis revealed the multitarget potential of citral against A. baumannii. Furthermore, citral treatment enhances the susceptibility of A. baumannii to the host innate immune system and reactive oxygen species (ROS). Cytotoxicity analysis revealed the nonfatal effect of citral on human PBMCs. Therefore, citral could be the safest therapeutic compound and can be taken for further clinical evaluation for the treatment of biofilm-associated infections by A. baumannii. Acinetobacter baumannii has been reported as a multidrug-resistant bacterium due to biofilms and antimicrobial resistance mechanisms. Hence, novel therapeutic strategies are necessary to overcome A. baumannii infections. This study revealed that citral at 200 μg/ml attenuated A. baumannii biofilms by up to 90% without affecting viability. Furthermore, microscopic analyses and in vitro assays confirmed the antibiofilm efficacy of citral. The global effect of citral on A. baumannii was evaluated by proteomic, transcriptional, and in silico approaches. Two-dimensional (2D) gel electrophoresis and matrix-assisted laser desorption ionization–time of flight/time of flight (MALDI-TOF/TOF) analyses were used to assess the effect of citral on the A. baumannii cellular proteome. Quantitative real-time PCR (qPCR) analysis was done to validate the proteomic data and identify the differentially expressed A. baumannii genes. Protein-protein interactions, gene enrichment, and comparative gene network analyses were performed to explore the interactions and functional attributes of differentially expressed proteins of A. baumannii. Global omics-based analyses revealed that citral targeted various mechanisms such as biofilm formation, antibiotic resistance, antioxidant defense, iron acquisition, and type II and type IV secretion systems. The results of antioxidant analyses and antibiotic sensitivity, blood survival, lipase, and hemolysis assays validated the proteomic results. Cytotoxicity analysis showed a nontoxic effect of citral on peripheral blood mononuclear cells (PBMCs). Overall, the current study unveiled that citral has multitarget efficacy to inhibit the biofilm formation and virulence of A. baumannii. IMPORTANCEAcinetobacter baumannii is a nosocomial-infection-causing bacterium and also possesses multidrug resistance to a wide range of conventional antibiotics. The biofilm-forming ability of A. baumannii plays a major role in its resistance and persistence. There is an alarming need for novel treatment strategies to control A. baumannii biofilm-associated issues. The present study demonstrated the strong antibiofilm and antivirulence efficacy of citral against A. baumannii. In addition, proteomic analysis revealed the multitarget potential of citral against A. baumannii. Furthermore, citral treatment enhances the susceptibility of A. baumannii to the host innate immune system and reactive oxygen species (ROS). Cytotoxicity analysis revealed the nonfatal effect of citral on human PBMCs. Therefore, citral could be the safest therapeutic compound and can be taken for further clinical evaluation for the treatment of biofilm-associated infections by A. baumannii.
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Tang X, Yu L, Yi Y, Wang J, Wang S, Meng C, Liu S, Hao Y, Zhang Y, Cao X, Jian H, Xiao X. Phylogenomic analysis reveals a two-stage process of the evolutionary transition of Shewanella from the upper ocean to the hadal zone. Environ Microbiol 2020; 23:744-756. [PMID: 32657519 DOI: 10.1111/1462-2920.15162] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Revised: 06/21/2020] [Accepted: 07/10/2020] [Indexed: 12/17/2022]
Abstract
Shewanella strains are characterized by versatile metabolic capabilities, resulting in their wide distribution in the ocean at different depths. Considering that particle sedimentation is an important dynamic process in the ocean, we hypothesized that hadal Shewanella species evolved from the upper ocean. In this study, we isolated three novel Shewanella strains from deep-sea sediments in the Southwest Indian Ocean. Genome sequencing indicated that strains YLB-06 and YLB-08 represent two novel species in the genus Shewanella. Through phylogenomic analysis, we showed that speciation and genomic changes in marine Shewanella strains are related to water depth. We further confirmed the aforementioned hypothesis and revealed a two-stage process of the evolutionary transition of Shewanella from the upper ocean to the hadal zone by comparative genomics and gene gain/loss analysis. Finally, the transcriptomic analysis demonstrated that recently obtained genes are strictly repressed and may thus play a minor role in the response to environmental changes.
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Affiliation(s)
- Xixiang Tang
- Key Laboratory of Marine Genetic Resources, Third Institute of Oceanography, Ministry of Natural Resources, Xiamen, 361005, China.,China Ocean Sample Repository (Biology), Xiamen, 361005, China
| | - Libo Yu
- Key Laboratory of Marine Genetic Resources, Third Institute of Oceanography, Ministry of Natural Resources, Xiamen, 361005, China.,China Ocean Sample Repository (Biology), Xiamen, 361005, China
| | - Yi Yi
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Jiahua Wang
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Siyuan Wang
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Canxing Meng
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Shunzhang Liu
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Yali Hao
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Yue Zhang
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Xiaorong Cao
- Key Laboratory of Marine Genetic Resources, Third Institute of Oceanography, Ministry of Natural Resources, Xiamen, 361005, China.,China Ocean Sample Repository (Biology), Xiamen, 361005, China
| | - Huahua Jian
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Xiang Xiao
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China.,State Key Laboratory of Ocean Engineering, School of Naval Architecture, Ocean and Civil Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China.,Laboratory for Marine Biology and Biotechnology, Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao, 266237, China
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8
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Imam N, Alam A, Ali R, Siddiqui MF, Ali S, Malik MZ, Ishrat R. In silico characterization of hypothetical proteins from Orientia tsutsugamushi str. Karp uncovers virulence genes. Heliyon 2019; 5:e02734. [PMID: 31720472 PMCID: PMC6838952 DOI: 10.1016/j.heliyon.2019.e02734] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Revised: 04/29/2019] [Accepted: 10/23/2019] [Indexed: 11/20/2022] Open
Abstract
Scrub typhus also known as bush typhus is a disease with symptoms similar to Chikungunya infection. It is caused by a gram-negative bacterium Orientia tsutsugamushi which resides in its vertebrate host, Mites. The genome of Orientia tsutsugamushi str. Karp encodes for 1,563 proteins, of which 344 are characterized as hypothetical ones. In the present study, we tried to identify the probable functions of these 344 hypothetical proteins (HPs). All the characterized hypothetical proteins (HPs) belong to the various protein classes like enzymes, transporters, binding proteins, metabolic process and catalytic activity and kinase activity. These hypothetical proteins (HPs) were further analyzed for virulence factors with 62 proteins identified as the most virulent proteins among these hypothetical proteins (HPs). In addition, we studied the protein sequence similarity network for visualizing functional trends across protein superfamilies from the context of sequence similarity and it shows great potential for generating testable hypotheses about protein structure-function relationships. Furthermore, we calculated toplogical properties of the network and found them to obey network power law distributions showing a fractal nature. We also identifed two highly interconnected modules in the main network which contained five hub proteins (KJV55465, KJV56211, KJV57212, KJV57203 and KJV57216) having 1.0 clustering coefficient. The structural modeling (2D and 3D structure) of these five hub proteins was carried out and the catalytic site essential for its functioning was analyzed. The outcome of the present study may facilitate a better understanding of the mechanism of virulence, pathogenesis, adaptability to host and up-to-date annotations will make unknown genes easy to identify and target for experimentation. The information on the functional attributes and virulence characteristic of these hypothetical proteins (HPs) are envisaged to facilitate effective development of novel antibacterial drug targets of Orientia tsutsugamushi.
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Affiliation(s)
- Nikhat Imam
- Institute of Computer Science and Information Technology, Magadh University, Bodhgaya, India
- Centre for Interdisciplinary Research in Basic Science, Jamia Millia Islamia, New Delhi, India
| | - Aftab Alam
- Centre for Interdisciplinary Research in Basic Science, Jamia Millia Islamia, New Delhi, India
| | - Rafat Ali
- Centre for Interdisciplinary Research in Basic Science, Jamia Millia Islamia, New Delhi, India
| | - Mohd Faizan Siddiqui
- International Medical Faculty, Osh State University, Osh City, 723500, Kyrgyz Republic (Kyrgyzstan)
| | - Sher Ali
- Centre for Interdisciplinary Research in Basic Science, Jamia Millia Islamia, New Delhi, India
| | - Md. Zubbair Malik
- School of Computational and Integrative Sciences, Jawaharlal Nehru University, New Delhi, Delhi, 110067, India
| | - Romana Ishrat
- Centre for Interdisciplinary Research in Basic Science, Jamia Millia Islamia, New Delhi, India
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9
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Multiple Mechanisms Are Involved in Repression of Filamentous Phage SW1 Transcription by the DNA-Binding Protein FpsR. J Mol Biol 2019; 431:1113-1126. [DOI: 10.1016/j.jmb.2019.01.040] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2018] [Revised: 01/16/2019] [Accepted: 01/31/2019] [Indexed: 01/21/2023]
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10
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Partially Reciprocal Replacement of FlrA and FlrC in Regulation of Shewanella oneidensis Flagellar Biosynthesis. J Bacteriol 2018; 200:JB.00796-17. [PMID: 29358496 DOI: 10.1128/jb.00796-17] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2017] [Accepted: 01/17/2018] [Indexed: 12/23/2022] Open
Abstract
In some bacteria with a polar flagellum, an established regulatory hierarchy controlling stepwise assembly of the organelle consists of four regulators: FlrA, σ54, FlrBC, and σ28 Because all of these regulators mediate the expression of multiple targets, they are essential to the assembly of a functional flagellum and therefore to motility. However, this is not the case for the gammaproteobacterium Shewanella oneidensis: cells lacking FlrB, FlrC, or both remain flagellated and motile. In this study, we unravel the underlying mechanism, showing that FlrA and FlrC are partially substitutable for each other in regulating flagellar assembly. While both regulators are bacterial enhancer binding proteins (bEBPs) for σ54, FlrA differs from FlrC in its independence of σ54 for its own transcription and its inability to activate the flagellin gene flaA These differences largely account for the distinct phenotypes resulting from the loss or overproduction of FlrA and FlrC.IMPORTANCE The assembly of a polar flagellum in bacteria has been characterized as relying on four regulators, FlrA, σ54, FlrBC, and σ28, in a hierarchical manner. They all are essential to the process and therefore to motility, except in S. oneidensis, in which FlrB, FlrC, or both together are not essential. Here we show that FlrA and FlrC, as bEBPs, are partially reciprocal in functionality in this species. As a consequence, the presence of one allows flagellar assembly and motility in the other's absence. Despite this, there are significant differences in the physiological roles played by these two regulators: FlrA is the master regulator of flagellar assembly, whereas FlrC fine-tunes motility. These intriguing observations open up a new avenue to further exploration of the regulation of flagellar assembly.
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11
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Wang Y, Zhang Y, Yin Z, Wang J, Zhu Y, Peng H, Zhou D, Qi Z, Yang W. H-NS represses transcription of the flagellin gene lafA of lateral flagella in Vibrio parahaemolyticus. Can J Microbiol 2017; 64:69-74. [PMID: 29091745 DOI: 10.1139/cjm-2017-0315] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Swarming motility is ultimately mediated by the proton-powered lateral flagellar (laf) system in Vibrio parahaemolyticus. Expression of laf genes is tightly regulated by a number of environmental conditions and regulatory factors. The nucleoid-associated DNA-binding protein H-NS is a small and abundant protein that is widely distributed in bacteria, and H-NS-like protein-dependent expression of laf genes has been identified in Vibrio cholerae and V. parahaemolyticus. The data presented here show that H-NS acts as a repressor of the swarming motility in V. parahaemolyticus. A single σ28-dependent promoter was detected for lafA encoding the flagellin of the lateral flagella, and its activity was directly repressed by H-NS. Thus, H-NS represses swarming motility by directly acting on lafA. Briefly, this work revealed a novel function for H-NS as a repressor of the expression of lafA and swarming motility in V. parahaemolyticus.
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Affiliation(s)
- Yan Wang
- a Department of Biological Defence (Microbiology), Faculty of Tropical Medicine and Public Health, Second Military Medical University, Shanghai, 200433, China
| | - Yiquan Zhang
- b School of Medicine, Jiangsu University, Zhenjiang 212013, Jiangsu, China
| | - Zhe Yin
- c State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China
| | - Jie Wang
- c State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China
| | - Yongzhe Zhu
- a Department of Biological Defence (Microbiology), Faculty of Tropical Medicine and Public Health, Second Military Medical University, Shanghai, 200433, China
| | - Haoran Peng
- a Department of Biological Defence (Microbiology), Faculty of Tropical Medicine and Public Health, Second Military Medical University, Shanghai, 200433, China
| | - Dongsheng Zhou
- c State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China
| | - Zhongtian Qi
- a Department of Biological Defence (Microbiology), Faculty of Tropical Medicine and Public Health, Second Military Medical University, Shanghai, 200433, China
| | - Wenhui Yang
- c State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China
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12
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Jian H, Li S, Tang X, Xiao X. A transcriptome resource for the deep-sea bacterium Shewanella piezotolerans WP3 under cold and high hydrostatic pressure shock stress. Mar Genomics 2016; 30:87-91. [PMID: 27720170 DOI: 10.1016/j.margen.2016.09.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2016] [Revised: 09/27/2016] [Accepted: 09/27/2016] [Indexed: 11/27/2022]
Abstract
Low temperature and high hydrostatic pressure (HHP) are two of the most remarkable environmental factors influencing deep-sea ecosystem. The adaptive mechanisms of microorganisms which live in these extreme environments to low temperature and high pressure warrant investigation. In this study, the global gene expression patterns of the deep-sea bacterium Shewanella piezotolerans WP3 in response to cold (0 °C) and HHP (50 MPa) shock were evaluated through DNA microarray analysis. Results revealed that 22, 66, and 106 genes were differentially expressed after WP3 was respectively exposed to cold shock for 30, 60, and 90 min. Of these genes, 16 genes were identified as common differentially expressed genes (DEGs). After 30 min and 120 min of HHP shock, 5 and 10 genes were respectively identified as DEGs. The hierarchical clustering analysis of the DEG pattern indicated that WP3 may employ different adaptive strategies to cope with cold and HHP shock stress. Taken together, our study provided a transcriptome resource for deep-sea bacterial responses to cold and HHP stress. This study also established a basis for further investigations on environmental adaptive mechanisms utilized by benthic bacteria.
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Affiliation(s)
- Huahua Jian
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, PR China
| | - Shengkang Li
- Guangdong Provincial Key Laboratory of Marine Biology, Shantou University, Shantou, PR China; Marine Biology Institute, Shantou University, Shantou, PR China
| | - Xixiang Tang
- Key Laboratory of Marine Biogenetic Resources, Third Institute of Oceanography, State Oceanic Administration, Xiamen, PR China; South China Sea Bio-Resource Exploitation and Utilization Collaborative Innovation Center, Xiamen, PR China
| | - Xiang Xiao
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, PR China; State Key Laboratory of Ocean Engineering, School of Naval Architecture, Ocean and Civil Engineering, Shanghai Jiao Tong University, Shanghai, PR China.
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