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Han S, Cheng X, Wang T, Li X, Cai Z, Zheng H, Xiao B, Zhou J. AI-2 quorum sensing signal disrupts coral symbiotic homeostasis and induces host bleaching. ENVIRONMENT INTERNATIONAL 2024; 188:108768. [PMID: 38788416 DOI: 10.1016/j.envint.2024.108768] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2024] [Revised: 04/19/2024] [Accepted: 05/20/2024] [Indexed: 05/26/2024]
Abstract
Symbiotic microorganisms play critical ecophysiological roles that facilitate the maintenance of coral health. Currently, information on the gene and protein pathways contributing to bleaching responses is lacking, including the role of autoinducers. Although the autoinducer AI-1 is well understood, information on AI-2 is insufficient. Here, we observed a 3.7-4.0 times higher abundance of the AI-2 synthesis gene luxS in bleached individuals relative to their healthy counterparts among reef-building coral samples from the natural environment. Laboratory tests further revealed that AI-2 contributed significantly to an increase in coral bleaching, altered the ratio of potential probiotic and pathogenic bacteria, and suppressed the antiviral activity of specific pathogenic bacteria while enhancing their functional potential, such as energy metabolism, chemotaxis, biofilm formation and virulence release. Structural equation modeling indicated that AI-2 influences the microbial composition, network structure, and pathogenic features, which collectively contribute to the coral bleaching status. Collectively, our results offer novel potential strategies for coral conservation based on a signal manipulation approach.
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Affiliation(s)
- Shuo Han
- Marine Ecology and Human Factors Assessment Technical Innovation Center of Natural Resources Ministry, Tsinghua Shenzhen International Graduate School, Shenzhen 518055, Guangdong Province, PR China; Shenzhen Public Platform for Screening and Application of Marine Microbial Resources, Institute for Ocean Engineering, Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, Guangdong Province, PR China; Shenzhen Key Laboratory of Advanced Technology for Marine Ecology, Institute for Ocean Engineering, Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, Guangdong Province, PR China
| | - Xueyu Cheng
- Marine Ecology and Human Factors Assessment Technical Innovation Center of Natural Resources Ministry, Tsinghua Shenzhen International Graduate School, Shenzhen 518055, Guangdong Province, PR China; Shenzhen Public Platform for Screening and Application of Marine Microbial Resources, Institute for Ocean Engineering, Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, Guangdong Province, PR China; Shenzhen Key Laboratory of Advanced Technology for Marine Ecology, Institute for Ocean Engineering, Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, Guangdong Province, PR China
| | - Tao Wang
- Marine Ecology and Human Factors Assessment Technical Innovation Center of Natural Resources Ministry, Tsinghua Shenzhen International Graduate School, Shenzhen 518055, Guangdong Province, PR China; Shenzhen Public Platform for Screening and Application of Marine Microbial Resources, Institute for Ocean Engineering, Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, Guangdong Province, PR China
| | - Xinyang Li
- Marine Ecology and Human Factors Assessment Technical Innovation Center of Natural Resources Ministry, Tsinghua Shenzhen International Graduate School, Shenzhen 518055, Guangdong Province, PR China; Shenzhen Public Platform for Screening and Application of Marine Microbial Resources, Institute for Ocean Engineering, Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, Guangdong Province, PR China; Shenzhen Key Laboratory of Advanced Technology for Marine Ecology, Institute for Ocean Engineering, Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, Guangdong Province, PR China
| | - Zhonghua Cai
- Marine Ecology and Human Factors Assessment Technical Innovation Center of Natural Resources Ministry, Tsinghua Shenzhen International Graduate School, Shenzhen 518055, Guangdong Province, PR China; Shenzhen Public Platform for Screening and Application of Marine Microbial Resources, Institute for Ocean Engineering, Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, Guangdong Province, PR China
| | - Huina Zheng
- Guangdong Ocean University Shenzhen Research Institute, Shenzhen 518055, PR China
| | - Baohua Xiao
- Guangdong Ocean University Shenzhen Research Institute, Shenzhen 518055, PR China
| | - Jin Zhou
- Marine Ecology and Human Factors Assessment Technical Innovation Center of Natural Resources Ministry, Tsinghua Shenzhen International Graduate School, Shenzhen 518055, Guangdong Province, PR China; Shenzhen Public Platform for Screening and Application of Marine Microbial Resources, Institute for Ocean Engineering, Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, Guangdong Province, PR China; Shenzhen Key Laboratory of Advanced Technology for Marine Ecology, Institute for Ocean Engineering, Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, Guangdong Province, PR China.
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2
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Li J, Dai H, Bashir A, Wang Z, An Y, Yu X, Xu L, Li L. Nematicidal activity and action mode of a methyl-accepting chemotaxis protein from Pseudomonas syringae against Caenorhabditis elegans. Heliyon 2024; 10:e30366. [PMID: 38707475 PMCID: PMC11068812 DOI: 10.1016/j.heliyon.2024.e30366] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2023] [Revised: 04/23/2024] [Accepted: 04/24/2024] [Indexed: 05/07/2024] Open
Abstract
The conventional phytopathogen Pseudomonas syringae reportedly possesses several virulence determinants against Caenorhabditis elegans; however, their action mechanisms remain elusive. This study reports the nematicidal activity and action receptor of a methyl-accepting chemotaxis protein (MCP03) of a wild-type P. syringae MB03 against C. elegans. Purified MCP03 exhibited nematicidal toxicity against C. elegans at a half-lethal concentration of 124.4 μg mL-1, alongside detrimental effects on the growth and brood size of C. elegans. Additionally, MCP03-treated worms exhibited severe pathological destruction of the intestine and depressed wrinkles of the cuticle. Yeast two-hybrid assays identified a subunit of COP9 signalosome, namely CSN-5, which functioned as an MCP03 action receptor. In vitro pull-down verified the binding interaction between MCP03 and CSN-5. RNA interference assays confirmed that MCP03 antagonizes CSN-5, thereby adversely affecting the brood size and cuticle integrity of C. elegans. Following MCP03 infection, the expression of genes related to reproduction, growth, and cuticle formation, such as kgb-1, unc-98, and col-117, was considerably downregulated, indicating pathological changes in MCP03-treated nematodes. Therefore, we proposed that MCP03 antagonizes CSN-5, causing lethality as well as detrimental effects on the fertility, growth, and morphogenesis of C. elegans, which can provide new insights into the signaling pathways and mechanisms underlying the nematicidal action of MCP03 toward C. elegans.
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Affiliation(s)
- Jiaoqing Li
- Guangdong Provincial Key Laboratory of Conservation and Precision Utilization of Characteristic Agricultural Resources in Mountainous Areas, School of Life Sciences, Jiaying University, Meizhou 514015, China
| | - Haiyan Dai
- National Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Anum Bashir
- National Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Zhiyong Wang
- National Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Yimin An
- Pomelo Engineering Technology Center, School of Life Sciences, Jiaying University, Meizhou 514015, China
| | - Xun Yu
- National Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Liangzheng Xu
- Guangdong Provincial Key Laboratory of Conservation and Precision Utilization of Characteristic Agricultural Resources in Mountainous Areas, School of Life Sciences, Jiaying University, Meizhou 514015, China
| | - Lin Li
- National Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
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3
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Chauhan R, Tall BD, Gopinath G, Azmi W, Goel G. Environmental risk factors associated with the survival, persistence, and thermal tolerance of Cronobacter sakazakii during the manufacture of powdered infant formula. Crit Rev Food Sci Nutr 2023; 63:12224-12239. [PMID: 35838158 DOI: 10.1080/10408398.2022.2099809] [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] [Indexed: 11/03/2022]
Abstract
Cronobacter sakazakii is an opportunistic foodborne pathogen of concern for foods having low water activity such as powdered infant formula (PIF). Its survival under desiccated stress can be attributed to its ability to adapt effectively to many different environmental stresses. Due to the high risk to neonates and its sporadic outbreaks in PIF, C. sakazakii received great attention among the scientific community, food industry and health care providers. There are many extrinsic and intrinsic factors that affect C. sakazakii survival in low-moisture foods. Moreover, short- or long-term pre-exposure to sub-lethal physiological stresses which are commonly encountered in food processing environments are reported to affect the thermal resistance of C. sakazakii. Additionally, acclimation to these stresses may render C. sakazakii resistance to antibiotics and other antimicrobial agents. This article reviews the factors and the strategies responsible for the survival and persistence of C. sakazakii in PIF. Particularly, studies focused on the influence of various factors on thermal resistance, antibiotic or antimicrobial resistance, virulence potential and stress-associated gene expression are reviewed.
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Affiliation(s)
- Rajni Chauhan
- Department of Biotechnology, Himachal Pradesh University, Shimla, India
| | | | - Gopal Gopinath
- Center for Food Safety and Applied Nutrition, U. S. Food and Drug Administration, Laurel, MD, USA
| | - Wamik Azmi
- Department of Biotechnology, Himachal Pradesh University, Shimla, India
| | - Gunjan Goel
- Department of Microbiology, School of Interdisciplinary and Applied Sciences, Central University of Haryana, Mahindra, India
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4
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Zhu D, Fan Y, Wang X, Li P, Huang Y, Jiao J, Zhao C, Li Y, Wang S, Du X. Characterization of Molecular Chaperone GroEL as a Potential Virulence Factor in Cronobacter sakazakii. Foods 2023; 12:3404. [PMID: 37761113 PMCID: PMC10528849 DOI: 10.3390/foods12183404] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2023] [Revised: 09/04/2023] [Accepted: 09/06/2023] [Indexed: 09/29/2023] Open
Abstract
The molecular chaperone GroEL of C. sakazakii, a highly conserved protein encoded by the gene grol, has the basic function of responding to heat shock, thus enhancing the bacterium's adaptation to dry and high-temperature environments, which poses a threat to food safety and human health. Our previous study demonstrated that GroEL was found in the bacterial membrane fraction and caused a strong immune response in C. sakazakii. In this study, we tried to elucidate the subcellular location and virulent effects of GroEL. In live C. sakazakii cells, GroEL existed in both the soluble and insoluble fractions. To study the secretory mechanism of GroEL protein, a non-reduced Western immunoblot was used to analyze the form of the protein, and the result showed that the exported GroEL protein was mainly in monomeric form. The exported GroEL could also be located on bacterial surface. To further research the virulent effect of C. sakazakii GroEL, an indirect immunofluorescence assay was used to detect the adhesion of recombinant GroEL protein to HCT-8 cells. The results indicated that the recombinant GroEL protein could adhere to HCT-8 cells in a short period of time. The recombinant GroEL protein could activate the NF-κB signaling pathway to release more pro-inflammatory cytokines (TNF-α, IL-6 and IL-8), downregulating the expression of tight-junction proteins (claudin-1, occluding, ZO-1 and ZO-2), which collectively resulted in dose-dependent virulent effects on host cells. Inhibition of the grol gene expression resulted in a significant decrease in bacterial adhesion to and invasion of HCT-8 cells. Moreover, the deficient GroEL also caused slow growth, decreased biofilm formation, defective motility and abnormal filamentation of the bacteria. In brief, C. sakazakii GroEL was an important virulence factor. This protein was not only crucial for the physiological activity of C. sakazakii but could also be secreted to enhance the bacterium's adhesion and invasion capabilities.
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Affiliation(s)
- Dongdong Zhu
- State Key Laboratory of Food Nutrition and Safety, College of Food Science and Engineering, Tianjin University of Science and Technology, Tianjin 300457, China; (D.Z.); (Y.F.); (X.W.); (P.L.); (Y.H.); (J.J.); (C.Z.); (Y.L.); (S.W.)
| | - Yufei Fan
- State Key Laboratory of Food Nutrition and Safety, College of Food Science and Engineering, Tianjin University of Science and Technology, Tianjin 300457, China; (D.Z.); (Y.F.); (X.W.); (P.L.); (Y.H.); (J.J.); (C.Z.); (Y.L.); (S.W.)
| | - Xiaoyi Wang
- State Key Laboratory of Food Nutrition and Safety, College of Food Science and Engineering, Tianjin University of Science and Technology, Tianjin 300457, China; (D.Z.); (Y.F.); (X.W.); (P.L.); (Y.H.); (J.J.); (C.Z.); (Y.L.); (S.W.)
| | - Ping Li
- State Key Laboratory of Food Nutrition and Safety, College of Food Science and Engineering, Tianjin University of Science and Technology, Tianjin 300457, China; (D.Z.); (Y.F.); (X.W.); (P.L.); (Y.H.); (J.J.); (C.Z.); (Y.L.); (S.W.)
| | - Yaping Huang
- State Key Laboratory of Food Nutrition and Safety, College of Food Science and Engineering, Tianjin University of Science and Technology, Tianjin 300457, China; (D.Z.); (Y.F.); (X.W.); (P.L.); (Y.H.); (J.J.); (C.Z.); (Y.L.); (S.W.)
| | - Jingbo Jiao
- State Key Laboratory of Food Nutrition and Safety, College of Food Science and Engineering, Tianjin University of Science and Technology, Tianjin 300457, China; (D.Z.); (Y.F.); (X.W.); (P.L.); (Y.H.); (J.J.); (C.Z.); (Y.L.); (S.W.)
| | - Chumin Zhao
- State Key Laboratory of Food Nutrition and Safety, College of Food Science and Engineering, Tianjin University of Science and Technology, Tianjin 300457, China; (D.Z.); (Y.F.); (X.W.); (P.L.); (Y.H.); (J.J.); (C.Z.); (Y.L.); (S.W.)
| | - Yue Li
- State Key Laboratory of Food Nutrition and Safety, College of Food Science and Engineering, Tianjin University of Science and Technology, Tianjin 300457, China; (D.Z.); (Y.F.); (X.W.); (P.L.); (Y.H.); (J.J.); (C.Z.); (Y.L.); (S.W.)
| | - Shuo Wang
- State Key Laboratory of Food Nutrition and Safety, College of Food Science and Engineering, Tianjin University of Science and Technology, Tianjin 300457, China; (D.Z.); (Y.F.); (X.W.); (P.L.); (Y.H.); (J.J.); (C.Z.); (Y.L.); (S.W.)
- Tianjin Key Laboratory of Food Science and Health, School of Medicine, Nankai University, Tianjin 300071, China
| | - Xinjun Du
- State Key Laboratory of Food Nutrition and Safety, College of Food Science and Engineering, Tianjin University of Science and Technology, Tianjin 300457, China; (D.Z.); (Y.F.); (X.W.); (P.L.); (Y.H.); (J.J.); (C.Z.); (Y.L.); (S.W.)
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5
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Li P, Zong W, Zhang Z, Lv W, Ji X, Zhu D, Du X, Wang S. Effects and molecular mechanism of flagellar gene flgK on the motility, adhesion/invasion, and desiccation resistance of Cronobacter sakazakii. Food Res Int 2023; 164:112418. [PMID: 36738023 DOI: 10.1016/j.foodres.2022.112418] [Citation(s) in RCA: 15] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Revised: 12/21/2022] [Accepted: 12/26/2022] [Indexed: 12/29/2022]
Abstract
Cronobacter sakazakii (C. sakazakii), a food-borne pathogen, can infect neonates, elderly and immunocompromised populations with a high infection and mortality rate. However, the specific molecular mechanism of its motility, biofilm formation, cell adhesion, and desiccation resistance remains unclear, and flagellum hook associated protein (FlgK), a main component of the flagellar complex, may be an important determinant of its virulence and desiccation resistance. In this study, the flgK mutant strain (ΔflgK) was constructed using the homologous recombination method, and the cpflgK complementary strain was obtained by gene complementation, followed by analysis of the difference between the wild type (WT), mutant, and complementary strains in mobility, biofilm formation, cell adhesion, and desiccation resistance. Results indicated that flgK gene played a positive role in motility and invasion, with no significant effect on biofilm formation. Interestingly, flagellar assembly gene deletion showed increased resistance of C. sakazakii to dehydration. The mechanism underlying the negative correlation of flgK gene with dehydration resistance was further investigated by using the high-throughput sequencing technology to compare the gene expression between WT and ΔflgK strains after drying. The results revealed up-regulation in the expression of 54 genes, including genes involved in osmosis and formate dehydrogenase, while down-regulation in the expression of 50 genes, including genes involved in flagellum hook and nitrate reductase. qRT-PCR analysis of the RNA-seq data further indicated that the flgK gene played an important role in the environmental stress resistance of C. sakazakii by up-regulating the formate dehydrogenase, betaine synthesis, and arginine deiminase pathways, due to dynamic proton imbalance caused by lack of flagella. This study facilitates our understanding of the roles of flgK in motion-related functions and the molecular mechanism of desiccation resistance in C. sakazakii.
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Affiliation(s)
- Ping Li
- State Key Laboratory of Food Nutrition and Safety, College of Food Science and Engineering, Tianjin University of Science and Technology, Tianjin 300457, China
| | - Wenyue Zong
- State Key Laboratory of Food Nutrition and Safety, College of Food Science and Engineering, Tianjin University of Science and Technology, Tianjin 300457, China
| | - Zhengyang Zhang
- State Key Laboratory of Food Nutrition and Safety, College of Food Science and Engineering, Tianjin University of Science and Technology, Tianjin 300457, China
| | - Wen Lv
- State Key Laboratory of Food Nutrition and Safety, College of Food Science and Engineering, Tianjin University of Science and Technology, Tianjin 300457, China
| | - Xuemeng Ji
- Tianjin Key Laboratory of Food Science and Health, College of Medicine, Nankai University, Tianjin 300071, China
| | - Dongdong Zhu
- State Key Laboratory of Food Nutrition and Safety, College of Food Science and Engineering, Tianjin University of Science and Technology, Tianjin 300457, China
| | - Xinjun Du
- State Key Laboratory of Food Nutrition and Safety, College of Food Science and Engineering, Tianjin University of Science and Technology, Tianjin 300457, China.
| | - Shuo Wang
- State Key Laboratory of Food Nutrition and Safety, College of Food Science and Engineering, Tianjin University of Science and Technology, Tianjin 300457, China; Tianjin Key Laboratory of Food Science and Health, College of Medicine, Nankai University, Tianjin 300071, China.
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6
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Li QC, Wang B, Zeng YH, Cai ZH, Zhou J. The Microbial Mechanisms of a Novel Photosensitive Material (Treated Rape Pollen) in Anti-Biofilm Process under Marine Environment. Int J Mol Sci 2022; 23:ijms23073837. [PMID: 35409199 PMCID: PMC8998240 DOI: 10.3390/ijms23073837] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2022] [Revised: 03/18/2022] [Accepted: 03/24/2022] [Indexed: 02/01/2023] Open
Abstract
Marine biofouling is a worldwide problem in coastal areas and affects the maritime industry primarily by attachment of fouling organisms to solid immersed surfaces. Biofilm formation by microbes is the main cause of biofouling. Currently, application of antibacterial materials is an important strategy for preventing bacterial colonization and biofilm formation. A natural three-dimensional carbon skeleton material, TRP (treated rape pollen), attracted our attention owing to its visible-light-driven photocatalytic disinfection property. Based on this, we hypothesized that TRP, which is eco-friendly, would show antifouling performance and could be used for marine antifouling. We then assessed its physiochemical characteristics, oxidant potential, and antifouling ability. The results showed that TRP had excellent photosensitivity and oxidant ability, as well as strong anti-bacterial colonization capability under light-driven conditions. Confocal laser scanning microscopy showed that TRP could disperse pre-established biofilms on stainless steel surfaces in natural seawater. The biodiversity and taxonomic composition of biofilms were significantly altered by TRP (p < 0.05). Moreover, metagenomics analysis showed that functional classes involved in the antioxidant system, environmental stress, glucose−lipid metabolism, and membrane-associated functions were changed after TRP exposure. Co-occurrence model analysis further revealed that TRP markedly increased the complexity of the biofilm microbial network under light irradiation. Taken together, these results demonstrate that TRP with light irradiation can inhibit bacterial colonization and prevent initial biofilm formation. Thus, TRP is a potential nature-based green material for marine antifouling.
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Affiliation(s)
- Qing-Chao Li
- Shenzhen Public Platform for Screening and Application of Marine Microbial Resources, Institute for Ocean Engineering, Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, China; (Q.-C.L.); (Y.-H.Z.); (Z.-H.C.)
| | - Bo Wang
- CAS Key Laboratory of Quantitative Engineering Biology, Shenzhen Institute of Synthetic Biology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China;
| | - Yan-Hua Zeng
- Shenzhen Public Platform for Screening and Application of Marine Microbial Resources, Institute for Ocean Engineering, Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, China; (Q.-C.L.); (Y.-H.Z.); (Z.-H.C.)
| | - Zhong-Hua Cai
- Shenzhen Public Platform for Screening and Application of Marine Microbial Resources, Institute for Ocean Engineering, Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, China; (Q.-C.L.); (Y.-H.Z.); (Z.-H.C.)
| | - Jin Zhou
- Shenzhen Public Platform for Screening and Application of Marine Microbial Resources, Institute for Ocean Engineering, Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, China; (Q.-C.L.); (Y.-H.Z.); (Z.-H.C.)
- Correspondence:
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7
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Posautz A, Szostak MP, Cabal Rosel A, Allerberger F, Stöger A, Rab G, Feßler AT, Spergser J, Kübber-Heiss A, Schwarz S, Forsythe SJ, Ruppitsch W, Loncaric I. Outbreak of Cronobacter turicensis in European brown hares (Lepus europaeus). Lett Appl Microbiol 2022; 74:1008-1015. [PMID: 35263446 DOI: 10.1111/lam.13685] [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: 01/13/2022] [Revised: 02/21/2022] [Accepted: 02/24/2022] [Indexed: 11/30/2022]
Abstract
This is the first report of acute deaths in five European brown hares (Lepus europaeus) attributed to mucoid and necrotizing typhlocolitis caused by genetically different Cronobacter (C.) turicensis strains in northeastern Austria. As this opportunistic pathogen is mainly known for causing disease in immunocompromised humans and neonates, this previously unrecognized potential for a spillover from a wildlife reservoir to humans warrants further attention.
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Affiliation(s)
| | | | | | | | - Anna Stöger
- Austrian Agency for Health and Food Safety, Vienna, Austria
| | - Gerhard Rab
- Institute of Hydraulic Engineering and Water Resources Management, University of Technology Vienna, Austria.,Institute for Land and Water Management Research, Federal Agency for Water Management, Petzenkirchen, Austria
| | - Andrea T Feßler
- Freie Universität Berlin, Berlin, Germany; Veterinary Centre for Resistance Research (TZR), Department of Veterinary Medicine, Freie Universität Berlin, 14163, Berlin, Germany
| | | | | | - Stefan Schwarz
- Freie Universität Berlin, Berlin, Germany; Veterinary Centre for Resistance Research (TZR), Department of Veterinary Medicine, Freie Universität Berlin, 14163, Berlin, Germany
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8
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Cao Y, Li L, Zhang Y, Liu F, Xiao X, Li X, Yu Y. Evaluation of Cronobacter sakazakii biofilm formation after sdiA knockout in different osmotic pressure conditions. Food Res Int 2022; 151:110886. [PMID: 34980413 DOI: 10.1016/j.foodres.2021.110886] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Revised: 11/23/2021] [Accepted: 12/02/2021] [Indexed: 12/26/2022]
Abstract
This study characterizes the impact of sdiA on biofilm formation under normal or osmotic stress conditions in Cronobacter sakazakii by constructing a sdiA deletion mutant (ΔsdiA). Here, the downregulation of flagellar assembly-related genes and upregulation of capsular, cellulose and lipopolysaccharide biosynthesis-associated genes in ΔsdiA were observed when compared to the wild type strain (WT) through transcriptomic analysis. Meanwhile, reduced ability of motility, enhanced cell surface hydrophobicity and stronger biofilms with extracellular matrix were observed in WT with deletion of sdiA. Both WT and ΔsdiA formed more biofilm in low osmotic stress medium, while in hyperosmolarity conditions, formation of biofilm was dramatically reduced. Our findings supported that sdiA might suppress biofilm formation of C. sakazakii by regulating biosynthesis of flagellar and extracellular polymeric substances. This study investigates the role of sdiA on biofilm formation in C. sakazakii, and provides the basis for the inhibition of C. sakazakii in food industry and infant-feeding.
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Affiliation(s)
- Yifang Cao
- School of Food Science and Engineering, South China University of Technology, Guangzhou City, Guangdong Province 510640, China
| | - Li Li
- School of Food Science and Engineering, South China University of Technology, Guangzhou City, Guangdong Province 510640, China
| | - Yan Zhang
- School of Food Science and Engineering, South China University of Technology, Guangzhou City, Guangdong Province 510640, China
| | - Fengsong Liu
- School of Food Science and Engineering, South China University of Technology, Guangzhou City, Guangdong Province 510640, China
| | - Xinglong Xiao
- School of Food Science and Engineering, South China University of Technology, Guangzhou City, Guangdong Province 510640, China.
| | - Xiaofeng Li
- School of Food Science and Engineering, South China University of Technology, Guangzhou City, Guangdong Province 510640, China
| | - Yigang Yu
- School of Food Science and Engineering, South China University of Technology, Guangzhou City, Guangdong Province 510640, China.
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9
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Ji X, Lu P, Hu Y, Xue J, Wu J, Zhang B, Zhang Y, Dong L, Lv H, Wang S. Function Characterization of Endogenous Plasmids in Cronobacter sakazakii and Identification of p-Coumaric Acid as Plasmid-Curing Agent. Front Microbiol 2021; 12:687243. [PMID: 34248908 PMCID: PMC8267800 DOI: 10.3389/fmicb.2021.687243] [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: 03/29/2021] [Accepted: 05/25/2021] [Indexed: 11/13/2022] Open
Abstract
Virulence traits and antibiotic resistance are frequently provided by genes located on plasmids. However, experimental verification of the functions of these genes is often lacking due to a lack of related experimental technology. In the present study, an integrated suicide vector was used to efficiently and specifically delete a bacterial endogenous plasmid in Cronobacter sakazakii. The pESA3 plasmid was removed from C. sakazakii BAA-894, and we confirmed that this plasmid contributes to the invasion and virulence of this strain. In addition, the pGW1 plasmid was expunged from C. sakazakii GZcsf-1, and we confirmed that this plasmid confers multidrug resistance. We further screened plasmid-curing agents and found that p-coumaric acid had a remarkable effect on the curing of pESA3 and pGW1 at sub-inhibitory concentrations. Our study investigated the contribution of endogenous plasmids pESA3 and pGW1 by constructing plasmid-cured strains using suicide vectors and suggested that p-coumaric acid can be a safe and effective plasmid-curing agent for C. sakazakii.
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Affiliation(s)
- Xuemeng Ji
- Tianjin Key Laboratory of Food Science and Health, School of Medicine, Nankai University, Tianjin, China
| | - Ping Lu
- Institute of Radiation Medicine, Chinese Academy of Medical Sciences and Peking Union Medical Collage, Tianjin, China
| | - Yaozhong Hu
- Tianjin Key Laboratory of Food Science and Health, School of Medicine, Nankai University, Tianjin, China
| | - Juan Xue
- Institute of Infection and Immunity, Taihe Hospital, Hubei University of Medicine, Shiyan, China
| | - Jing Wu
- Tianjin Key Laboratory of Food Science and Health, School of Medicine, Nankai University, Tianjin, China
| | - Bowei Zhang
- Tianjin Key Laboratory of Food Science and Health, School of Medicine, Nankai University, Tianjin, China
| | - Yan Zhang
- Tianjin Key Laboratory of Food Science and Health, School of Medicine, Nankai University, Tianjin, China
| | - Lu Dong
- Tianjin Key Laboratory of Food Science and Health, School of Medicine, Nankai University, Tianjin, China
| | - Huan Lv
- Tianjin Key Laboratory of Food Science and Health, School of Medicine, Nankai University, Tianjin, China
| | - Shuo Wang
- Tianjin Key Laboratory of Food Science and Health, School of Medicine, Nankai University, Tianjin, China
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10
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Xu Z, Liu Z, Soteyome T, Hua J, Zhang L, Yuan L, Ye Y, Cai Z, Yang L, Chen L, Harro JM, Kjellerup BV, Liu J, Li Y. Impact of pmrA on Cronobacter sakazakii planktonic and biofilm cells: A comprehensive transcriptomic study. Food Microbiol 2021; 98:103785. [PMID: 33875213 DOI: 10.1016/j.fm.2021.103785] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2020] [Revised: 12/30/2020] [Accepted: 03/05/2021] [Indexed: 10/21/2022]
Abstract
Cronobacter sakazakii is an emerging opportunistic foodborne pathogen causing rare but severe infections in neonates. Furthermore, the formation of biofilm allows C. sakazakii to persist in different environments. We have demonstrated that the mutator phenotype ascribed to deficiency of the pmrA gene results in more biomass in the first 24 h but less during the post maturation stage (7-14 d) compared with BAA 894. The present study aimed to investigate the regulatory mechanism modulating biofilm formation due to pmrA mutation. The transcriptomic analyses of BAA 894 and s-3 were performed by RNA-sequencing on planktonic and biofilm cells collected at different time points. According to the results, when comparing biofilm to planktonic cells, expression of genes encoding outer membrane proteins, lysozyme, etc. were up-regulated, with LysR family transcriptional regulators, periplasmic proteins, etc. down-regulated. During biofilm formation, cellulose synthase operon genes, flagella-related genes, etc. played essential roles in different stages. Remarkably, pmrA varies the expression of a number of genes related to motility, biofilm formation, and antimicrobial resistance, including srfB, virK, mviM encoding virulence factor, flgF, fliN, etc. encoding flagellar assembly, and marA, ramA, etc. encoding AraC family transcriptional regulators in C. sakazakii. This study provides valuable insights into transcriptional regulation of C. sakazakii pmrA mutant during biofilm formation.
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Affiliation(s)
- Zhenbo Xu
- School of Food Science and Engineering, Guangdong Province Key Laboratory for Green Processing of Natural Products and Product Safety, South China University of Technology, Guangzhou, 510640, China; Department of Clinical Pharmacy and Translational Science, College of Pharmacy, University of Tennessee Health Science Center, Memphis, TN, 38103, USA; Home Economics Technology, Rajamangala University of Technology Phra Nakhon, Bangkok, Thailand; National Institute of Fundamental Studies, Hantana Road, Kandy, Sri Lanka; Overseas Expertise Introduction Center for Discipline Innovation of Food Nutrition and Human Health (111 Center), Guangzhou, 510640, China
| | - Ziqi Liu
- School of Food Science and Engineering, Guangdong Province Key Laboratory for Green Processing of Natural Products and Product Safety, South China University of Technology, Guangzhou, 510640, China
| | - Thanapop Soteyome
- National Institute of Fundamental Studies, Hantana Road, Kandy, Sri Lanka
| | - Jingjing Hua
- National Engineering Laboratory for Cereal Fermentation Technology, Jiangnan University, 1800 Lihu Road, Wuxi, 214122, China
| | - Liang Zhang
- National Engineering Laboratory for Cereal Fermentation Technology, Jiangnan University, 1800 Lihu Road, Wuxi, 214122, China.
| | - Lei Yuan
- College of Food Science and Engineering, Yangzhou University, Yangzhou, China
| | - Yanrui Ye
- School of Biological Science and Engineering, South China University of Technology, Guangzhou, 510640, China
| | - Zhao Cai
- School of Medicine, Southern University of Science and Technology, Shenzhen, 518055, Guangdong, China
| | - Liang Yang
- School of Medicine, Southern University of Science and Technology, Shenzhen, 518055, Guangdong, China
| | - Ling Chen
- School of Food Science and Engineering, Guangdong Province Key Laboratory for Green Processing of Natural Products and Product Safety, South China University of Technology, Guangzhou, 510640, China
| | - Janette M Harro
- Department of Microbial Pathogenesis, School of Dentistry, University of Maryland, Baltimore, MD, 21201, USA
| | - Birthe Veno Kjellerup
- Department of Civil and Environmental Engineering, University of Maryland, College Park, MD, 20742, USA
| | - Junyan Liu
- Department of Civil and Environmental Engineering, University of Maryland, College Park, MD, 20742, USA
| | - Yanyan Li
- Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, 18 Shilongshan Road, Xihu District, Hangzhou, 310024, Zhejiang Province, China.
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11
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Yokoyama F, Imai T, Aoki W, Ueda M, Kawamoto J, Kurihara T. Identification of a Putative Sensor Protein Involved in Regulation of Vesicle Production by a Hypervesiculating Bacterium, Shewanella vesiculosa HM13. Front Microbiol 2021; 12:629023. [PMID: 33679653 PMCID: PMC7930318 DOI: 10.3389/fmicb.2021.629023] [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: 11/13/2020] [Accepted: 01/29/2021] [Indexed: 11/20/2022] Open
Abstract
Bacteria secrete and utilize nanoparticles, called extracellular membrane vesicles (EMVs), for survival in their growing environments. Therefore, the amount and components of EMVs should be tuned in response to the environment. However, how bacteria regulate vesiculation in response to the extracellular environment remains largely unknown. In this study, we identified a putative sensor protein, HM1275, involved in the induction of vesicle production at high lysine concentration in a hypervesiculating Gram-negative bacterium, Shewanella vesiculosa HM13. This protein was predicted to possess typical sensing and signaling domains of sensor proteins, such as methyl-accepting chemotaxis proteins. Comparison of vesicle production between the hm1275-disrupted mutant and the parent strain revealed that HM1275 is involved in lysine-induced hypervesiculation. Moreover, HM1275 has sequence similarity to a biofilm dispersion protein, BdlA, of Pseudomonas aeruginosa PAO1, and hm1275 disruption increased the amount of biofilm. Thus, this study showed that the induction of vesicle production and suppression of biofilm formation in response to lysine concentration are under the control of the same putative sensor protein.
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Affiliation(s)
| | - Tomoya Imai
- Research Institute for Sustainable Humanosphere, Kyoto University, Uji, Japan
| | - Wataru Aoki
- Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Kyoto, Japan.,Kyoto Integrated Science and Technology Bio-Analysis Center, Kyoto, Japan
| | - Mitsuyoshi Ueda
- Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Kyoto, Japan.,Kyoto Integrated Science and Technology Bio-Analysis Center, Kyoto, Japan
| | - Jun Kawamoto
- Institute for Chemical Research, Kyoto University, Uji, Japan
| | - Tatsuo Kurihara
- Institute for Chemical Research, Kyoto University, Uji, Japan
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12
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Karmakar R. State of the art of bacterial chemotaxis. J Basic Microbiol 2021; 61:366-379. [PMID: 33687766 DOI: 10.1002/jobm.202000661] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2020] [Revised: 02/09/2021] [Accepted: 02/25/2021] [Indexed: 12/13/2022]
Abstract
Bacterial chemotaxis is a biased movement of bacteria toward the beneficial chemical gradient or away from a toxic chemical gradient. This movement is achieved by sensing a chemical gradient by chemoreceptors. In most of the chemotaxis studies, Escherichia coli has been used as a model organism. E. coli have about 4-6 flagella on their surfaces, and the motility is achieved by rotating the flagella. Each flagellum has reversible flagellar motors at its base, which rotate the flagella in counterclockwise and clockwise directions to achieve "run" and "tumble." The chemotaxis of bacteria is regulated by a network of interacting proteins. The sensory signal is processed and transmitted to the flagellar motor by cytoplasmic proteins. Bacterial chemotaxis plays an important role in many biological processes such as biofilm formation, quorum sensing, bacterial pathogenesis, and host infection. Bacterial chemotaxis can be applied for bioremediation, horizontal gene transfer, drug delivery, or maybe some other industry in near future. This review contains an overview of bacterial chemotaxis, recent findings of the physiological importance of bacterial chemotaxis in other biological processes, and the application of bacterial chemotaxis.
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Affiliation(s)
- Richa Karmakar
- Department of Physics, University of California San Diego, La Jolla, California, USA
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13
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Zhou A, Cao Y, Zhou D, Hu S, Tan W, Xiao X, Yu Y, Li X. Global transcriptomic analysis of Cronobacter sakazakii CICC 21544 by RNA-seq under inorganic acid and organic acid stresses. Food Res Int 2019; 130:108963. [PMID: 32156398 DOI: 10.1016/j.foodres.2019.108963] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2019] [Revised: 12/23/2019] [Accepted: 12/25/2019] [Indexed: 01/07/2023]
Abstract
Cronobacter sakazakii is a common foodborne pathogen that can tolerate various stress conditions. Acidic environment is a common stress condition encountered by bacteria in food processing and gastrointestinal digestion, including both inorganic and organic acids. In order to elucidate the Acid Tolerance Response (ATR) of C. sakazakii, we performed high-throughput RNA-seq to compare gene expression under hydrochloric acid and citric acid stresses. In this study, 107 differentially expressed genes (DEGs) were identified in both acids, of which 85 DEGs were functionally related to the regulation of acid tolerance. Multiple layers of mechanisms may be applied by C. sakazakii in response to acid stress: Firstly, in order to reduce excessive intracellular protons, C. sakazakii pumps them out through trans-membrane proteins or consumes them through metabolic reactions. Secondly, under acidic conditions, a large amount of reactive oxygen species and hydroxyl radicals accumulate in the cells, resulting in oxidative damage. C. sakazakii protects cells by up-regulating the antioxidant stress genes such as soxS and madB. Thirdly, C. sakazakii chooses energy efficient metabolic pathways to reduce energy consumption and maintain necessary processes. Finally, genes involved in chemotaxis and motility were differentially expressed to respond to different acidic conditions. This study systematically analyzed the acid-resistant mechanism of C. sakazakii under the stress of organic and inorganic acids, and provided a theoretical basis for better control of its contamination in food.
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Affiliation(s)
- Ailian Zhou
- School of Food Sciences and Engineering, South China University of Technology, Guangzhou City, Guangdong Province 510640, China
| | - Yifang Cao
- School of Food Sciences and Engineering, South China University of Technology, Guangzhou City, Guangdong Province 510640, China
| | - Donggen Zhou
- Ningbo International Travel Healthcare Center. No. 336 Liuting Street, Haishu District, Ningbo City, Zhejiang Province 315012, China
| | - Shuangfang Hu
- Key Laboratory of Molecular Epidemiology of Shenzhen, Shenzhen Center for Disease Control and Prevention, Shenzhen City, Guangdong Province 518055, China
| | - Wanjing Tan
- School of Food Sciences and Engineering, South China University of Technology, Guangzhou City, Guangdong Province 510640, China
| | - Xinglong Xiao
- School of Food Sciences and Engineering, South China University of Technology, Guangzhou City, Guangdong Province 510640, China.
| | - Yigang Yu
- School of Food Sciences and Engineering, South China University of Technology, Guangzhou City, Guangdong Province 510640, China
| | - Xiaofeng Li
- State Key Laboratory of Pulp and Paper Engineering, College of Light Industry and Food Sciences, South China University of Technology, 381 Wusan Road, Tianhe District, Guangzhou City 510640, Guangdong Province, China.
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14
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Sheng S, Xin L, Yam JKH, Salido MM, Khong NZJ, Liu Q, Chea RA, Li HY, Yang L, Liang ZX, Xu L. The MapZ-Mediated Methylation of Chemoreceptors Contributes to Pathogenicity of Pseudomonas aeruginosa. Front Microbiol 2019; 10:67. [PMID: 30804897 PMCID: PMC6370697 DOI: 10.3389/fmicb.2019.00067] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Accepted: 01/15/2019] [Indexed: 12/22/2022] Open
Abstract
The pathogenic bacterium Pseudomonas aeruginosa is notorious for causing acute and chronic infections in humans. The ability to infect host by P. aeruginosa is dependent on a complex cellular signaling network, which includes a large number of chemosensory signaling pathways that rely on the methyl-accepting chemotaxis proteins (MCPs). We previously found that the second messenger c-di-GMP-binding adaptor MapZ modulates the methylation of an amino acid-detecting MCP by directly interacting with a chemotaxis methyltransferase CheR1. The current study further expands our understanding of the role of MapZ in regulating chemosensory pathways by demonstrating that MapZ suppresses the methylation of multiple MCPs in P. aeruginosa PAO1. The MCPs under the control of MapZ include five MCPs (Aer, CtpH, CptM, PctA, and PctB) for detecting oxygen/energy, inorganic phosphate, malate and amino acids, and three MCPs (PA1251, PA1608, and PA2867) for detecting unknown chemoattractant or chemorepellent. Chemotaxis assays showed that overexpression of MapZ hampered the taxis of P. aeruginosa toward chemoattractants and scratch-wounded human cells. Mouse infection experiments demonstrated that a dysfunction in MapZ regulation had a profound negative impact on the dissemination of P. aeruginosa and resulted in attenuated bacterial virulence. Together, the results imply that by controlling the methylation of various MCPs via the adaptor protein MapZ, c-di-GMP exerts a profound influence on chemotactic responses and bacterial pathogenesis.
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Affiliation(s)
- Shuo Sheng
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou, China.,Guangdong Innovative and Entrepreneurial Research Team of Sociomicrobiology, South China Agricultural University, Guangzhou, China
| | - Lingyi Xin
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore.,Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
| | - Joey Kuok Hoong Yam
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore.,Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore.,Interdisciplinary Graduate School, Nanyang Technological University, Singapore, Singapore
| | - May Margarette Salido
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore.,Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore.,Interdisciplinary Graduate School, Nanyang Technological University, Singapore, Singapore
| | - Nicole Zi Jia Khong
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| | - Qiong Liu
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou, China.,Guangdong Innovative and Entrepreneurial Research Team of Sociomicrobiology, South China Agricultural University, Guangzhou, China
| | - Rachel Andrea Chea
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| | - Hoi Yeung Li
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| | - Liang Yang
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore.,Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore.,Interdisciplinary Graduate School, Nanyang Technological University, Singapore, Singapore
| | - Zhao-Xun Liang
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore.,Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
| | - Linghui Xu
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou, China.,Guangdong Innovative and Entrepreneurial Research Team of Sociomicrobiology, South China Agricultural University, Guangzhou, China
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15
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Wang Z, Wang C, You Y, Xu W, Lv Z, Liu Z, Chen W, Shi Y, Wang J. Response of Pseudomonas fluorescens to dimethyl phthalate. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2019; 167:36-43. [PMID: 30292974 DOI: 10.1016/j.ecoenv.2018.09.078] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2018] [Revised: 09/14/2018] [Accepted: 09/18/2018] [Indexed: 06/08/2023]
Abstract
Dimethyl phthalate (DMP) is a ubiquitous pollutant that is very harmful to organisms due to its mutagenicity, teratogenicity and carcinogenicity. Pseudomonas fluorescens (P. fluorescens) is one of the most important bacteria in the environment. In this study, the response of P. fluorescens to DMP was investigated. It was found that DMP greatly inhibited the growth and glucose utilization of P. fluorescens when the concentration of DMP was ranged from 20 to 40 mg/l. The surface hydrophobicity and membrane permeability of P. fluorescens were also increased by DMP. DMP could lead to the deformations of cell membrane and the mis-opening of membrane channels. RNA-Seq and RT-qPCR results showed that the expression of some genes in P. fluorescens were altered, including the genes involved in energy metabolism, ATP-binding cassette (ABC) transporting and two-component systems. Additionally, the productions of lactic acid and pyruvic acid were reduced and the activity of hexokinase was inhibited in P. fluorescens by DMP. Clearly, the results suggested that DMP contamination could alter the biological function of P. fluorescens in the environment.
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Affiliation(s)
- Zhigang Wang
- School of Life Science and Agriculture and Forestry, Qiqihar University, Qiqihar, Heilongjiang, 161006, China.
| | - Chunlong Wang
- School of Life Science and Agriculture and Forestry, Qiqihar University, Qiqihar, Heilongjiang, 161006, China.
| | - Yimin You
- School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai 200240, China.
| | - Weihui Xu
- School of Life Science and Agriculture and Forestry, Qiqihar University, Qiqihar, Heilongjiang, 161006, China.
| | - Zhihang Lv
- School of Life Science and Agriculture and Forestry, Qiqihar University, Qiqihar, Heilongjiang, 161006, China.
| | - Zeping Liu
- School of Life Science and Agriculture and Forestry, Qiqihar University, Qiqihar, Heilongjiang, 161006, China.
| | - Wenjing Chen
- School of Life Science and Agriculture and Forestry, Qiqihar University, Qiqihar, Heilongjiang, 161006, China.
| | - Yiran Shi
- School of Life Science and Agriculture and Forestry, Qiqihar University, Qiqihar, Heilongjiang, 161006, China.
| | - Junhe Wang
- Qiqihar Branch of Heilongjiang Academy of Agricultural Sciences, Qiqihar, Heilongjiang, 161006, China.
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16
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Balaraman P, Plettner E. Chemotaxis by Pseudomonas putida (ATCC 17453) towards camphor involves cytochrome P450 cam (CYP101A1). Biochim Biophys Acta Gen Subj 2018; 1863:304-312. [PMID: 30391161 DOI: 10.1016/j.bbagen.2018.10.018] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2018] [Revised: 10/27/2018] [Accepted: 10/29/2018] [Indexed: 11/29/2022]
Abstract
The camphor-degrading microorganism, Pseudomonas putida strain ATCC 17453, is an aerobic, gram-negative soil bacterium that uses camphor as its sole carbon and energy source. The genes responsible for the catabolic degradation of camphor are encoded on the extra-chromosomal CAM plasmid. A monooxygenase, cytochrome P450cam, mediates hydroxylation of camphor to 5-exo-hydroxycamphor as the first and committed step in the camphor degradation pathway, requiring a dioxygen molecule (O2) from air. Under low O2 levels, P450cam catalyzes the production of borneol via an unusual reduction reaction. We have previously shown that borneol downregulates the expression of P450cam. To understand the function of P450cam and the consequences of down-regulation by borneol under low O2 conditions, we have studied chemotaxis of camphor induced and non-induced P. putida strain ATCC 17453. We have tested camphor, borneol, oxidized camphor metabolites and known bacterial attractants (d)-glucose, (d) - and (l)-glutamic acid for their elicitation chemotactic behavior. In addition, we have used 1-phenylimidazole, a P450cam inhibitor, to investigate if P450cam plays a role in the chemotactic ability of P. putida in the presence of camphor. We found that camphor, a chemoattractant, became toxic and chemorepellent when P450cam was inhibited. We have also evaluated the effect of borneol on chemotaxis and found that the bacteria chemotaxed away from camphor in the presence of borneol. This is the first report of the chemotactic behaviour of P. putida ATCC 17453 and the essential role of P450cam in this process.
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Affiliation(s)
- Priyadarshini Balaraman
- Department of Chemistry, Simon Fraser University, 8888 University Drive, Burnaby, BC, V5A 1S6, Canada
| | - Erika Plettner
- Department of Chemistry, Simon Fraser University, 8888 University Drive, Burnaby, BC, V5A 1S6, Canada.
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17
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Matilla MA, Krell T. The effect of bacterial chemotaxis on host infection and pathogenicity. FEMS Microbiol Rev 2018; 42:4563582. [PMID: 29069367 DOI: 10.1093/femsre/fux052] [Citation(s) in RCA: 152] [Impact Index Per Article: 25.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2017] [Accepted: 10/19/2017] [Indexed: 12/26/2022] Open
Abstract
Chemotaxis enables microorganisms to move according to chemical gradients. Although this process requires substantial cellular energy, it also affords key physiological benefits, including enhanced access to growth substrates. Another important implication of chemotaxis is that it also plays an important role in infection and disease, as chemotaxis signalling pathways are broadly distributed across a variety of pathogenic bacteria. Furthermore, current research indicates that chemotaxis is essential for the initial stages of infection in different human, animal and plant pathogens. This review focuses on recent findings that have identified specific bacterial chemoreceptors and corresponding chemoeffectors associated with pathogenicity. Pathogenicity-related chemoeffectors are either host and niche-specific signals or intermediates of the host general metabolism. Plant pathogens were found to contain an elevated number of chemotaxis signalling genes and functional studies demonstrate that these genes are critical for their ability to enter the host. The expanding body of knowledge of the mechanisms underlying chemotaxis in pathogens provides a foundation for the development of new therapeutic strategies capable of blocking infection and preventing disease by interfering with chemotactic signalling pathways.
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Affiliation(s)
- Miguel A Matilla
- Department of Environmental Protection, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, 18008 Granada, Spain
| | - Tino Krell
- Department of Environmental Protection, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, 18008 Granada, Spain
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18
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Kim S, Yoon H, Ryu S. New virulence factor CSK29544_02616 as LpxA binding partner in Cronobacter sakazakii. Sci Rep 2018; 8:835. [PMID: 29339761 PMCID: PMC5770445 DOI: 10.1038/s41598-018-19306-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2017] [Accepted: 12/29/2017] [Indexed: 01/13/2023] Open
Abstract
Cronobacter sakazakii is an opportunistic pathogen that can cause meningitis and necrotizing enterocolitis in premature infants, but its virulence determinants remain largely unknown. In this study, a transposon-mediated random-mutant library of C. sakazakii was used to identify new virulence factors. Compared to wild-type bacteria, a mutant lacking CSK29544_02616 (referred to as labp) was defective in invasion into intestinal epithelial cells (by at least 1000-fold) and showed less phagocytosis by macrophages (by at least 50-fold). The lack of labp in C. sakazakii changed the profile of outer membrane proteins, decreased the production of lipopolysaccharides, and increased the production of membrane phospholipids. Bacterial physiological characteristics including surface hydrophobicity and motility were also altered in the absence of labp, presumably because of changes in the bacterial-envelope structure. To systematically determine the role of labp, ligand fishing was conducted using Labp as a bait, which revealed LpxA as a binding partner of Labp. LpxA is UDP-N-acetylglucosamine (GlcNAc) acyltransferase, the first enzyme in the pathway of lipid A biosynthesis. Labp increased the enzymatic activity of LpxA without influencing lpxA expression. Considering multifaceted roles of lipopolysaccharides in virulence regulation, Labp is a novel virulence factor that promotes the production of lipid A by LpxA in Cronobacter.
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Affiliation(s)
- Seongok Kim
- Department of Food and Animal Biotechnology, Department of Agricultural Biotechnology, Research Institute for Agriculture and Life Sciences, and Center for Food and Bioconvergence, Seoul National University, Seoul, 08826, Korea.,Department of Molecular Science and Technology, Department of Applied Chemistry and Biological Engineering, Ajou University, Suwon, 16499, South Korea
| | - Hyunjin Yoon
- Department of Molecular Science and Technology, Department of Applied Chemistry and Biological Engineering, Ajou University, Suwon, 16499, South Korea.
| | - Sangryeol Ryu
- Department of Food and Animal Biotechnology, Department of Agricultural Biotechnology, Research Institute for Agriculture and Life Sciences, and Center for Food and Bioconvergence, Seoul National University, Seoul, 08826, Korea.
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19
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Gao JX, Li P, Du XJ, Han ZH, Xue R, Liang B, Wang S. A Negative Regulator of Cellulose Biosynthesis, bcsR, Affects Biofilm Formation, and Adhesion/Invasion Ability of Cronobacter sakazakii. Front Microbiol 2017; 8:1839. [PMID: 29085341 PMCID: PMC5649176 DOI: 10.3389/fmicb.2017.01839] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2017] [Accepted: 09/08/2017] [Indexed: 12/17/2022] Open
Abstract
Cronobacter sakazakii is an important foodborne pathogen that causes neonatal meningitis and sepsis, with high mortality in neonates. However, very little information is available regarding the pathogenesis of C. sakazakii at the genetic level. In our previous study, a cellulose biosynthesis-related gene (bcsR) was shown to be involved in C. sakazakii adhesion/invasion into epithelial cells. In this study, the detailed functions of this gene were investigated using a gene knockout technique. A bcsR knockout mutant (ΔbcsR) of C. sakazakii ATCC BAA-894 showed decreased adhesion/invasion (3.9-fold) in human epithelial cell line HCT-8. Biofilm formation by the mutant was reduced to 50% of that exhibited by the wild-type (WT) strain. Raman spectrometry was used to detect variations in biofilm components caused by bcsR knockout, and certain components, including carotenoids, fatty acids, and amides, were significantly reduced. However, another biofilm component, cellulose, was increased in ΔbcsR, suggesting that bcsR negatively affects cellulose biosynthesis. This result was also verified via RT-PCR, which demonstrated up-regulation of five crucial cellulose synthesis genes (bcsA, B, C, E, Q) in ΔbcsR. Furthermore, the expression of other virulence or biofilm-related genes, including flagellar assembly genes (fliA, C, D) and toxicity-related genes (ompA, ompX, hfq), was studied. The expression of fliC and ompA in the ΔbcsR mutant was found to be remarkably reduced compared with that in the wild-type and the others were also affected excepted ompX. In summary, bcsR is a negative regulator of cellulose biosynthesis but positively regulates biofilm formation and the adhesion/invasion ability of C. sakazakii.
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Affiliation(s)
- Jian-Xin Gao
- Key Laboratory of Food Nutrition and Safety, Ministry of Education, Tianjin University of Science and Technology, Tianjin, China
| | - Ping Li
- Key Laboratory of Food Nutrition and Safety, Ministry of Education, Tianjin University of Science and Technology, Tianjin, China
| | - Xin-Jun Du
- Key Laboratory of Food Nutrition and Safety, Ministry of Education, Tianjin University of Science and Technology, Tianjin, China
| | - Zhong-Hui Han
- Key Laboratory of Food Nutrition and Safety, Ministry of Education, Tianjin University of Science and Technology, Tianjin, China
| | - Rui Xue
- Key Laboratory of Food Nutrition and Safety, Ministry of Education, Tianjin University of Science and Technology, Tianjin, China
| | - Bin Liang
- Key Laboratory of Food Nutrition and Safety, Ministry of Education, Tianjin University of Science and Technology, Tianjin, China
| | - Shuo Wang
- Key Laboratory of Food Nutrition and Safety, Ministry of Education, Tianjin University of Science and Technology, Tianjin, China.,Beijing Advanced Innovation Center for Food Nutrition and Human Health, Beijing Technology and Business University, Beijing, China
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20
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Salah Ud-Din AIM, Roujeinikova A. Methyl-accepting chemotaxis proteins: a core sensing element in prokaryotes and archaea. Cell Mol Life Sci 2017; 74:3293-3303. [PMID: 28409190 PMCID: PMC11107704 DOI: 10.1007/s00018-017-2514-0] [Citation(s) in RCA: 110] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2016] [Revised: 03/06/2017] [Accepted: 03/24/2017] [Indexed: 11/29/2022]
Abstract
Chemotaxis is the directed motility by means of which microbes sense chemical cues and relocate towards more favorable environments. Methyl-accepting chemotaxis proteins (MCPs) are the most common receptors in bacteria and archaea. They are arranged as trimers of dimers that, in turn, form hexagonal arrays in the cytoplasmic membrane or in the cytoplasm. Several different classes of MCPs have been identified according to their ligand binding region and membrane topology. MCPs have been further classified based on the length and sequence conservation of their cytoplasmic domains. Clusters of membrane-embedded MCPs often localize to the poles of the cell, whereas cytoplasmic MCPs can be targeted to the poles or distributed throughout the cell body. MCPs play an important role in cell survival, pathogenesis, and biodegradation. Bacterial adaptation to diverse environmental conditions promotes diversity among the MCPs. This review summarizes structure, classification, and structure-activity relationship of the known MCP receptors, with a brief overview of the signal transduction mechanisms in bacteria and archaea.
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Affiliation(s)
- Abu Iftiaf Md Salah Ud-Din
- Infection and Immunity Program, Monash Biomedicine Discovery Institute and Department of Microbiology, Monash University, Clayton, VIC, Australia
| | - Anna Roujeinikova
- Infection and Immunity Program, Monash Biomedicine Discovery Institute and Department of Microbiology, Monash University, Clayton, VIC, Australia.
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, VIC, Australia.
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Chen X, Wang L, Zhou J, Wu H, Li D, Cui Y, Lu B. Exiguobacterium sp. A1b/GX59 isolated from a patient with community-acquired pneumonia and bacteremia: genomic characterization and literature review. BMC Infect Dis 2017; 17:508. [PMID: 28732529 PMCID: PMC5521131 DOI: 10.1186/s12879-017-2616-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2017] [Accepted: 07/18/2017] [Indexed: 11/10/2022] Open
Abstract
Background Bacterial species belonging to the genus Exiguobacterium are facultative anaerobic, non-spore-forming, Gram-positive bacilli, and rarely associated with human infections. Herein, we reported the first case of community-acquired pneumonia (CAP) and bacteremia due to Exiguobacterium spp. in China. Case presentation An adult male with severe CAP was hospitalized. The pathogen was isolated from his bloodstream and broncho-alveolar lavage fluid. The correct identification of the micro-organism was achieved using 16S rRNA sequencing, and its antibiotic susceptibility test was performed by microdilution method. The Whole Genome Sequencing (WGS) was used to characterize its genetic features and to elucidate its potential pathogenic mechanisms. Furthermore, its genome sequence was also compared with those of 3 publicly-available Exiguobacterium strains. A PubMed search was performed for further understanding the features of Exiguobacterium infections. Phylogenetic analysis of the 16S rRNA gene sequence showed that the strain GX59 was most closely related to Exiguobacterium AT1b (99.7%). The genome of GX59 was 2,727,929 bp in size, harbouring 2855 putative protein-coding genes, 5 rRNA operons, 37 tRNA genes and 1 tmRNA. The multiple genome comparison of 4 Exiguobacterium strains demonstrated that Exiguobacterium contained 37 genes of secretion systems, including sec, tat, FEA, Type IV Pili and competence-related DNA transformation transporter (Com). Virulence factors of the micro-organism included tlyC, NprR, MCP, Dam, which might play a critical role in causing lethal infection. Conclusions The study highlighted the potential pathogenicity of the genus Exiguobacterium for its unique genes encoding various virulence factors and those associated with antibiotic resistance, therefore, its clinical significance should be valued.
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Affiliation(s)
- Xingchun Chen
- Department of Laboratory Medicine, People's Hospital of Guangxi Zhuang Autonomous Region, Nanning, 530021, China
| | - Lijun Wang
- Department of Laboratory Medicine, Beijing Tsinghua Chang Gung Hospital, Tsinghua University, Beijing, 102218, China
| | | | | | - Dong Li
- Department of Laboratory Medicine, Civil Aviation General Hospital, Peking University Civil Aviation School of Clinical Medicine, No1. Gaojing Street, Chaoyang District, Beijing, 100123, China
| | - Yanchao Cui
- Department of Laboratory Medicine, Civil Aviation General Hospital, Peking University Civil Aviation School of Clinical Medicine, No1. Gaojing Street, Chaoyang District, Beijing, 100123, China
| | - Binghuai Lu
- Department of Laboratory Medicine, Civil Aviation General Hospital, Peking University Civil Aviation School of Clinical Medicine, No1. Gaojing Street, Chaoyang District, Beijing, 100123, China.
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22
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Draft Genome Sequences of Pandrug-Resistant Serratia marcescens Clinical Isolates Harboring blaNDM-1. GENOME ANNOUNCEMENTS 2017; 5:5/3/e01481-16. [PMID: 28104656 PMCID: PMC5255929 DOI: 10.1128/genomea.01481-16] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The draft genome sequences of two clonal, pandrug-resistant Serratia marcescens clinical isolates were determined. The resistance phenotype was plasmid driven, as 14 of 17 resistance genes were present on large IncFIB(K), IncHI2, and IncA/C2 plasmids indicating a large pool of transmissible antibiotic resistance genes.
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Kim S, Kim YT, Yoon H, Lee JH, Ryu S. The complete genome sequence of Cronobacter sakazakii ATCC 29544 T, a food-borne pathogen, isolated from a child's throat. Gut Pathog 2017; 9:2. [PMID: 28053670 PMCID: PMC5209807 DOI: 10.1186/s13099-016-0150-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/11/2016] [Accepted: 12/07/2016] [Indexed: 11/10/2022] Open
Abstract
Background Cronobacter sakazakii is an emerging opportunistic pathogen that is associated with rare but life-threatening cases of severe diseases: meningitis, necrotizing enterocolitis, and sepsis in premature and full-term infants. However, the pathogenesis mechanism of this pathogen remains largely unknown. To determine its pathogenesis at the genomic level, the genome of C. sakazakii ATCC 29544T was completely sequenced and analyzed. Results The genomic DNA, containing a circular chromosome and three plasmids, is composed of 4,511,265 bp with a GC content of 56.71%, containing 4380 predicted open reading frames (ORFs), 22 rRNA genes, and 83 tRNA genes. The plasmids, designated pCSK29544_p1, pCSK29544_p2, and pCSK29544_p3, were 93,905-bp, 4938-bp, and 53,457-bp with GC contents of 57.02, 54.88, and 50.07%, respectively. They were also predicted to have 72, 6, and 57 ORFs without RNA genes. Conclusions The strain ATCC 29544T genome has ompA and ibeB-homologous cusC genes, probably associated with the invasion of human brain microvascular endothelial cells (BMECs). In addition, gene clusters for siderophore production (iucABCD/iutA) and the related transport system (eitCBAD) were detected in pCSK29544_p1 plasmid, indicating better iron uptake ability for survival. Furthermore, to survive under extremely dry condition like milk powder, this genome has gene clusters for biosynthesis of capsular proteins (CSK29544_00281-00284) and cellulose (CSK29544_01124-01127) for biofilm formation and a gene cluster for utilization of sialic acid in the milk (nanKTAR). The genome information of C. sakazakii ATCC 29544T would provide further understanding of its pathogenesis at the molecular level for the regulation of pathogenicity and the development of a rapid detection method using biomarkers. Electronic supplementary material The online version of this article (doi:10.1186/s13099-016-0150-0) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Seongok Kim
- Department of Food and Animal Biotechnology, Department of Agricultural Biotechnology, Research Institute for Agriculture and Life Sciences, and Center for Food and Bioconvergence, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826 Republic of Korea.,Department of Applied Chemistry and Biological Engineering, Ajou University, 206 Worldcup-ro, Yeongtong-gu, Suwon, 16499 Republic of Korea
| | - You-Tae Kim
- Department of Food Science and Biotechnology and Institute of Life Science and Resources, Kyung Hee University, 1732 Deogyeong-daero, Giheung-gu, Yongin-si, Gyeonggi-do, 17104 Republic of Korea
| | - Hyunjin Yoon
- Department of Applied Chemistry and Biological Engineering, Ajou University, 206 Worldcup-ro, Yeongtong-gu, Suwon, 16499 Republic of Korea
| | - Ju-Hoon Lee
- Department of Food Science and Biotechnology and Institute of Life Science and Resources, Kyung Hee University, 1732 Deogyeong-daero, Giheung-gu, Yongin-si, Gyeonggi-do, 17104 Republic of Korea
| | - Sangryeol Ryu
- Department of Food and Animal Biotechnology, Department of Agricultural Biotechnology, Research Institute for Agriculture and Life Sciences, and Center for Food and Bioconvergence, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826 Republic of Korea
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McEvoy K, Hayes J, Kealey C, Brady D. Influence of sweet whey protein concentrate and its hydrolysates on host-pathogen interactions in the emerging foodborne pathogen Cronobacter sakazakii. J Appl Microbiol 2016; 121:873-82. [PMID: 27337492 DOI: 10.1111/jam.13212] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2016] [Revised: 06/17/2016] [Accepted: 06/17/2016] [Indexed: 11/30/2022]
Abstract
AIMS Antimicrobial resistance poses a significant global healthcare predicament. An attractive approach to the dilemma of drug-resistant bacteria is the development and use of agents that interfere with the ability of pathogens to adhere to human tissue. The influence of sweet whey protein concentrate (SWPC), and selected hydrolysates of this material, on host-pathogen interactions of Cronobacter sakazakii (ATCC 29544) was investigated. METHODS AND RESULTS CaCo-2 cell line was selected as a suitable model for the human intestinal epithelium. Cronobacter sakazakiiATCC 29544 was identified as the strain with the highest adhesion efficiency. SWPC reduced its association by 80% (P < 0·01), invasion 35% (P < 0·01), and translocation >95% (P < 0·001). SWPC enzymatically modified with lipase, trypsin and pepsin had variable effects on these behaviours with the most significant effect exhibited with the lipase treatment. SWPC produced an almost total inhibition of translocation of C. sakazakii across a CaCo-2 cell monolayer. Lipase and pepsin treated SWPC also reduced translocation by 75% and 90% respectively. However, trypsin treatment nullified the effect SWPC had on translocation. The presence of viable bacterial cells and SWPC both increased expression of IL-8 following Cronobacter invasion into CaCo-2 cells. CONCLUSIONS Factors governing adherence, invasion and translocation of Cronobacter spp. to human intestinal cells are multi-factorial and digested milk products exhibit varying effects dependant on their enzyme modification and protein lipid content. SIGNIFICANCE AND IMPACT OF THE STUDY These findings contribute to our, as yet, incomplete understanding of Cronobacter pathogenesis, and suggest that SWPC in whole and enzymatically hydrolysed forms, may provide a cost-effective source of bioactive materials with inhibitory effects on bacterial virulence.
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Affiliation(s)
- K McEvoy
- Bioscience Research Institute, Athlone Institute of Technology, Athlone, Ireland.,Department of Life and Physical Sciences, Faculty of Science and Health, Athlone Institute of Technology, Athlone, Ireland
| | - J Hayes
- Bioscience Research Institute, Athlone Institute of Technology, Athlone, Ireland
| | - C Kealey
- Bioscience Research Institute, Athlone Institute of Technology, Athlone, Ireland.,Department of Life and Physical Sciences, Faculty of Science and Health, Athlone Institute of Technology, Athlone, Ireland
| | - D Brady
- Bioscience Research Institute, Athlone Institute of Technology, Athlone, Ireland.,Department of Life and Physical Sciences, Faculty of Science and Health, Athlone Institute of Technology, Athlone, Ireland
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25
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Abstract
Chemotaxis affords motile cells the ability to rapidly respond to environmental challenges by navigating cells to niches favoring growth. Such a property results from the activities of dedicated signal transduction systems on the motility apparatus, such as flagella, type IV pili, and gliding machineries. Once cells have reached a niche with favorable conditions, they often stop moving and aggregate into complex communities termed biofilms. An intermediate and reversible stage that precedes commitment to permanent adhesion often includes transient cell-cell contacts between motile cells. Chemotaxis signaling has been implicated in modulating the transient aggregation of motile cells. Evidence further indicates that chemotaxis-dependent transient cell aggregation events are behavioral responses to changes in metabolic cues that temporarily prohibit permanent attachment by maintaining motility and chemotaxis. This minireview discusses a few examples illustrating the role of chemotaxis signaling in the initiation of cell-cell contacts in bacteria moving via flagella, pili, or gliding.
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26
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Singh N, Goel G, Raghav M. Insights into virulence factors determining the pathogenicity of Cronobacter sakazakii. Virulence 2015; 6:433-40. [PMID: 25950947 PMCID: PMC4601314 DOI: 10.1080/21505594.2015.1036217] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2015] [Revised: 03/25/2015] [Accepted: 03/26/2015] [Indexed: 02/07/2023] Open
Abstract
Cronobacter sakazakii is an opportunistic pathogen associated with outbreaks of life-threatening necrotizing enterocolitis, meningitis and sepsis in neonates and infants. The pathogen possesses an array of virulence factors which aid in tissue adhesion, invasion and host cell injury. Although the identification and validation of C. sakazakii virulence factors has been hindered by availability of suitable neonatal animal model, various studies has reported outer membrane protein A (ompA) as a potential virulence marker. Various other plasmid associated genes such as filamentous hemagglutinin (fhaBC), Cronobacter plasminogen activator (cpa) and genes responsible for iron acquisition (eitCBAD and iucABD/iutA) have been reported in different strains of C. sakazakii. Besides these proposed virulence factors, several biophysical growth factors such as formation of biofilms and resistance to various environmental stresses also contributes to the pathogenic potential of this pathogen. This review provides an update on virulence determinants associated with the pathogenesis of C. sakazakii. The potential reservoirs of the pathogen, mode of transmission and epidemiology are also discussed.
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Affiliation(s)
- Niharika Singh
- Department of Biotechnology and Bioinformatics; Jaypee University of Information Technology; Waknaghat, Solan, India
| | - Gunjan Goel
- Department of Biotechnology and Bioinformatics; Jaypee University of Information Technology; Waknaghat, Solan, India
| | - Mamta Raghav
- Department of Biotechnology and Bioinformatics; Jaypee University of Information Technology; Waknaghat, Solan, India
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Yin L, Xue Y, Ma Y. Global Microarray Analysis of Alkaliphilic Halotolerant Bacterium Bacillus sp. N16-5 Salt Stress Adaptation. PLoS One 2015; 10:e0128649. [PMID: 26030352 PMCID: PMC4452262 DOI: 10.1371/journal.pone.0128649] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2015] [Accepted: 04/29/2015] [Indexed: 11/29/2022] Open
Abstract
The alkaliphilic halotolerant bacterium Bacillus sp. N16-5 is often exposed to salt stress in its natural habitats. In this study, we used one-colour microarrays to investigate adaptive responses of Bacillus sp. N16-5 transcriptome to long-term growth at different salinity levels (0%, 2%, 8%, and 15% NaCl) and to a sudden salt increase from 0% to 8% NaCl. The common strategies used by bacteria to survive and grow at high salt conditions, such as K+ uptake, Na+ efflux, and the accumulation of organic compatible solutes (glycine betaine and ectoine), were observed in Bacillus sp. N16-5. The genes of SigB regulon involved in general stress responses and chaperone-encoding genes were also induced by high salt concentration. Moreover, the genes regulating swarming ability and the composition of the cytoplasmic membrane and cell wall were also differentially expressed. The genes involved in iron uptake were down-regulated, whereas the iron homeostasis regulator Fur was up-regulated, suggesting that Fur may play a role in the salt adaption of Bacillus sp. N16-5. In summary, we present a comprehensive gene expression profiling of alkaliphilic Bacillus sp. N16-5 cells exposed to high salt stress, which would help elucidate the mechanisms underlying alkaliphilic Bacillus spp. survival in and adaptation to salt stress.
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Affiliation(s)
- Liang Yin
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Yanfen Xue
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Yanhe Ma
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
- * E-mail: (YM)
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