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Huang Z, Li Y, Yu K, Ma L, Pang B, Qin Q, Li J, Wang D, Gao H, Kan B. Genome-wide expanding of genetic evolution and potential pathogenicity in Vibrio alginolyticus. Emerg Microbes Infect 2024; 13:2350164. [PMID: 38687697 PMCID: PMC11132748 DOI: 10.1080/22221751.2024.2350164] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2024] [Accepted: 04/26/2024] [Indexed: 05/02/2024]
Abstract
Vibrio alginolyticus, an emergent species of Vibrio genus, exists in aquatic and marine environments. It has undergone genetic diversification, but its detailed genomic diversity is still unclear. Here, we performed a multi-dimensional comparative genomic analysis to explore the population phylogeny, virulence-related genes and potential drug resistance genes of 184 V. alginolyticus isolates. Although genetic diversity is complex, we analysed the population structure using three sub-datasets, including the subdivision for three lineages into sublineages and the distribution of strains in the marine ecological niche. Accessory genes, most of which reclassified V. alginolyticus genomes as different but with relatively close affinities, were nonuniformly distributed among these isolates. We demonstrated that the spread of some post-evolutionary isolates (mainly L3 strains isolated from Chinese territorial seas) was likely to be closely related to human activities, whereas other more ancestral strains (strains in the L1 and L2) tended to be locally endemic and formed clonal complex groups. In terms of pathogenicity, the potential virulence factors were mainly associated with toxin, adherence, motility, chemotaxis, and the type III secretion system (T3SS). We also found five types of antibacterial drug resistance genes. The prevalence of β-lactam resistance genes was 100%, which indicated that there may be a potential risk of natural resistance to β-lactam drugs. Our study reveals insights into genomic characteristics, evolution and potential virulence-associated gene profiles of V. alginolyticus.
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Affiliation(s)
- Zhenzhou Huang
- National Key Laboratory of Intelligent Tracking and Forecasting for Infectious Diseases, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, People’s Republic of China
- Hangzhou Center for Disease Control and Prevention, Zhejiang, People’s Republic of China
| | - Yanjun Li
- The Sixth Medical Center of PLA General Hospital, Beijing, People’s Republic of China
| | - Keyi Yu
- National Key Laboratory of Intelligent Tracking and Forecasting for Infectious Diseases, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, People’s Republic of China
| | - Lizhi Ma
- The Third Medical Center, Chinese PLA (People’s Liberation Army) General Hospital, Beijing, People’s Republic of China
| | - Bo Pang
- National Key Laboratory of Intelligent Tracking and Forecasting for Infectious Diseases, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, People’s Republic of China
| | - Qin Qin
- National Key Laboratory of Intelligent Tracking and Forecasting for Infectious Diseases, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, People’s Republic of China
| | - Jie Li
- National Key Laboratory of Intelligent Tracking and Forecasting for Infectious Diseases, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, People’s Republic of China
| | - Duochun Wang
- National Key Laboratory of Intelligent Tracking and Forecasting for Infectious Diseases, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, People’s Republic of China
| | - He Gao
- National Key Laboratory of Intelligent Tracking and Forecasting for Infectious Diseases, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, People’s Republic of China
| | - Biao Kan
- National Key Laboratory of Intelligent Tracking and Forecasting for Infectious Diseases, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, People’s Republic of China
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Abou-Okada M, Rashad MM, Ali GE, Abdel-Radi S, Hassan A. Oxidative stress, gene expression and histopathology of cultured gilthead sea bream (Sparus aurata) naturally co-infected with Ergasilus sieboldi and Vibrio alginolyticus. BMC Vet Res 2023; 19:277. [PMID: 38104092 PMCID: PMC10724927 DOI: 10.1186/s12917-023-03840-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2023] [Accepted: 12/01/2023] [Indexed: 12/19/2023] Open
Abstract
BACKGROUND Parasitic and bacterial co-infections have been associated with increasing fish mortalities and severe economic losses in aquaculture through the past three decades. The aim of this study was to evaluate the oxidative stress, histopathology, and immune gene expression profile of gilthead sea bream (Sparus aurata) co-infected with Ergasilus sieboldi and Vibrio alginolyticus. RESULTS Vibrio alginolyticus and Ergasilus sieboldi were identified using 16 S rRNA and 28 S rRNA sequencing, respectively. The collagenase virulence gene was found in all Vibrio alginolyticus isolates, and the multiple antimicrobial resistance index ranged from 0.286 to 0.857. Oxidant-antioxidant parameters in the gills, skin, and muscles of naturally infected fish revealed increased lipid peroxidation levels and a decrease in catalase and glutathione antioxidant activities. Moreover, naturally co-infected gilthead sea bream exhibited substantial up-regulation of il-1β, tnf-α, and cyp1a1. Ergasilus sieboldi encircled gill lamellae with its second antennae, exhibited severe gill architectural deformation with extensive eosinophilic granular cell infiltration. Vibrio alginolyticus infection caused skin and muscle necrosis in gilthead sea bream. CONCLUSION This study described some details about the gill, skin and muscle tissue defense mechanisms of gilthead sea bream against Ergasilus sieboldi and Vibrio alginolyticus co-infections. The prevalence of co-infections was 100%, and no resistant fish were detected. These co-infections imbalance the health status of the fish by hampering the oxidant-antioxidant mechanisms and proinflammatory/inflammatory immune genes to a more detrimental side. Our results suggest that simultaneous screening for bacterial and parasitic pathogens should be considered.
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Affiliation(s)
- Mahmoud Abou-Okada
- Department of Aquatic Animal Medicine and Management, Faculty of Veterinary Medicine, Cairo University, Giza, 12211, Egypt.
| | - Maha M Rashad
- Department of Biochemistry and Chemistry of Nutrition, Faculty of Veterinary Medicine, Cairo University, Giza, 12211, Egypt
| | - Ghada E Ali
- Department of Biochemistry and Chemistry of Nutrition, Faculty of Veterinary Medicine, Cairo University, Giza, 12211, Egypt
| | - Shimaa Abdel-Radi
- Department of Parasitology, Faculty of Veterinary Medicine, Cairo University, Giza, 12211, Egypt
| | - Azza Hassan
- Department of Pathology, Faculty of Veterinary Medicine, Cairo University, Giza, 12211, Egypt
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Yu M, Jiang C, Meng Y, Wang F, Qian J, Fei F, Yin Z, Zhao W, Zhao Y, Liu H. Effect of low temperature on the resistance of Listeria monocytogenes and Escherichia coli O157:H7 to acid electrolyzed water. Food Res Int 2023; 168:112776. [PMID: 37120223 DOI: 10.1016/j.foodres.2023.112776] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Revised: 02/13/2023] [Accepted: 03/24/2023] [Indexed: 03/29/2023]
Abstract
Low temperature can affect the resistance of pathogenic bacteria to other external stress. The present study was envisaged to assess the tolerance of L. monocytogenes and E. coli O157:H7 to acidic electrolyzed water (AEW) under low temperature stress. AEW treatment caused a damage to cell membrane of the pathogenic bacteria, which led to protein leakage and DNA damage. Compared with the pathogenic bacteria cultured at 37 °C (pure culture), the L. monocytogenes and E. coli O157:H7 cells cultivated at low temperature presented a less damage and had a higher survival rate when exposed to AEW. Therefore, 4 °C or 10 °C grown bacteria were less susceptible to AEW than those cultured at 37 °C. And this phenomenon was verified when AEW was used to treat the pathogenic bacteria inoculated in salmon. In addition, transcriptomic sequencing technology (RNA-seq) was used to reveal the mechanism of AEW tolerance of L. monocytogenes under low temperature stress. Transcriptomic analysis showed the expression of the cold shock protein, regulation of DNA-templated transcription, ribosome pathway, phosphotransferase system (PTS), bacteria chemotaxis, SOS response and DNA repair were involved in the resistance of L. monocytogenes to AEW. We speculated that the direct modulation of the expression of cold shock protein CspD, the indirect effect on the expression of cspD by inhibiting the expression of Crp/Fnr family transcriptional regulator or enhancing the level of cAMP by regulating PTS could reduce the resistance of L. monocytogenes cultivated at 4 °C to AEW. Our study contributes to solving the problem of the reduced bacteriostatic effect in cold storage environment.
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Screening of Staphylococcus aureus for Disinfection Evaluation and Transcriptome Analysis of High Tolerance to Chlorine-Containing Disinfectants. Microorganisms 2023; 11:microorganisms11020475. [PMID: 36838440 PMCID: PMC9967416 DOI: 10.3390/microorganisms11020475] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Accepted: 02/07/2023] [Indexed: 02/16/2023] Open
Abstract
The nonstandard use of disinfectants can lead to the disinfectant resistance of bacteria and even increase antibiotic resistance. However, compared with the study of antibiotic resistance, studies of bacterial resistance to disinfectants are relatively few in number. In this study, we explored the standard strain screening procedure for the evaluation of disinfection efficacy. Staphylococcus aureus strains with different sources and substrates were selected from the National Pathogen Resource Center of China and screened the standard strains that could evaluate the long-term bacteriostatic effect of the chlorine-containing disinfectants through the determination of the physical properties, genome-based safety evaluation, and disinfection test evaluation. In this process, one S. aureus strain was more resistant to the long-term bacteriostasis of chlorine-containing disinfectants than the other strains. This strain and the standard strain ATCC 6538 were cultured in the medium containing a low concentration of chlorine-containing disinfectant synchronously. Then, comparative transcriptome analysis was carried out to investigate the potential mechanism of a high tolerance to chlorine-containing disinfectants. The pathway of significant differential expression is related to the oxocarboxylic acid metabolic mechanism, amino acid metabolic mechanism, and pyrimidine mechanism, which may be the molecular mechanism of S. aureus evolution to adapt to chlorine-containing disinfectants. Our study established a technical process for screening and evaluating standard strains for disinfection, which also provided a reference for studying the bacterial evolution mechanism toward chlorine tolerance.
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Genomic Analysis Reveals Adaptation of Vibrio campbellii to the Hadal Ocean. Appl Environ Microbiol 2022; 88:e0057522. [PMID: 35916502 PMCID: PMC9397096 DOI: 10.1128/aem.00575-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
The genus Vibrio is characterized by high metabolic flexibility and genome plasticity and is widely distributed in the ocean from euphotic layers to deep-sea environments. The relationship between genome features and environmental adaptation strategies of Vibrio has been extensively investigated in coastal environments, yet very little is known about their survival strategies in oligotrophic deep-sea. In this study, we compared genomes of five Vibrio campbellii strains isolated from the Mariana and Yap Trenches at different water depths, including two epipelagic strains and three hadopelagic strains, to identify genomic characteristics that facilitate survival in the deep sea. Genome streamlining is found in pelagic strains, such as smaller genome sizes, lower G+C contents, and higher gene densities, which might be caused by long-term residence in an oligotrophic environment. Phylogenetic results showed that these five Vibrio strains are clustered into two clades according to their collection depth. Indeed, hadopelagic isolates harbor more genes involved in amino acid metabolism and transport, cell wall/membrane/envelope biogenesis, and inorganic ion transport and metabolism through comparative genomics analysis. Specific macrolide export gene and more tellurite resistance genes present in hadopelagic strains by the annotation of antibiotic and metal resistance genes. In addition, several genes related to substrate degradation are enriched in hadopelagic strains, such as chitinase genes, neopullulanase genes, and biopolymer transporter genes. In contrast, epipelagic strains are unique in their capacity for assimilatory nitrate reduction. The genomic characteristics investigated here provide insights into how Vibrio adapts to the deep-sea environment through genomic evolution. IMPORTANCE With the development of deep-sea sampling technology, an increasing number of deep-sea Vibrio strains have been isolated, but the adaptation mechanism of these eutrophic Vibrio strains to the deep-sea environment is unclear. Here, our results show that the genome of pelagic Vibrio is streamlined to adapt to a long-term oligotrophic environment. Through a phylogenomic analysis, we find that genomic changes in marine Vibrio campbellii strains are related to water depth. Our data suggest that an increase in genes related to antibiotic resistance, degradation of macromolecular and refractory substrates, and utilization of rare ions is related to the adaptation of V. campbellii strains to adapt to hadal environments, and most of the increased genes were acquired by horizontal gene transfer. These findings may deepen our understanding of adaptation strategies of marine bacteria to the extreme environment in hadal zones.
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Sanches-Fernandes GMM, Sá-Correia I, Costa R. Vibriosis Outbreaks in Aquaculture: Addressing Environmental and Public Health Concerns and Preventive Therapies Using Gilthead Seabream Farming as a Model System. Front Microbiol 2022; 13:904815. [PMID: 35898915 PMCID: PMC9309886 DOI: 10.3389/fmicb.2022.904815] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2022] [Accepted: 06/20/2022] [Indexed: 11/29/2022] Open
Abstract
Bacterial and viral diseases in aquaculture result in severe production and economic losses. Among pathogenic bacteria, species belonging to the Vibrio genus are one of the most common and widespread disease-causing agents. Vibrio infections play a leading role in constraining the sustainable growth of the aquaculture sector worldwide and, consequently, are the target of manifold disease prevention strategies. During the early, larval stages of development, Vibrio species are a common cause of high mortality rates in reared fish and shellfish, circumstances under which the host organisms might be highly susceptible to disease preventive or treatment strategies such as vaccines and antibiotics use, respectively. Regardless of host developmental stage, Vibrio infections may occur suddenly and can lead to the loss of the entire population reared in a given aquaculture system. Furthermore, the frequency of Vibrio-associated diseases in humans is increasing globally and has been linked to anthropic activities, in particular human-driven climate change and intensive livestock production. In this context, here we cover the current knowledge of Vibrio infections in fish aquaculture, with a focus on the model species gilthead seabream (Sparus aurata), a highly valuable reared fish in the Mediterranean climatic zone. Molecular methods currently used for fast detection and identification of Vibrio pathogens and their antibiotic resistance profiles are addressed. Targeted therapeutic approaches are critically examined. They include vaccination, phage therapy and probiotics supplementation, which bear promise in supressing vibriosis in land-based fish rearing and in mitigating possible threats to human health and the environment. This literature review suggests that antibiotic resistance is increasing among Vibrio species, with the use of probiotics constituting a promising, sustainable approach to prevent Vibrio infections in aquaculture.
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Affiliation(s)
- Gracinda M. M. Sanches-Fernandes
- Institute for Bioengineering and Biosciences, Biological Sciences Research Group, Instituto Superior Técnico, Universidade de Lisboa, Lisbon, Portugal
- Department of Bioengineering, Instituto Superior Técnico, Universidade de Lisboa, Lisbon, Portugal
- Associate Laboratory i4HB—Institute for Health and Bioeconomy at Instituto Superior Técnico, Universidade de Lisboa, Lisbon, Portugal
| | - Isabel Sá-Correia
- Institute for Bioengineering and Biosciences, Biological Sciences Research Group, Instituto Superior Técnico, Universidade de Lisboa, Lisbon, Portugal
- Department of Bioengineering, Instituto Superior Técnico, Universidade de Lisboa, Lisbon, Portugal
- Associate Laboratory i4HB—Institute for Health and Bioeconomy at Instituto Superior Técnico, Universidade de Lisboa, Lisbon, Portugal
| | - Rodrigo Costa
- Institute for Bioengineering and Biosciences, Biological Sciences Research Group, Instituto Superior Técnico, Universidade de Lisboa, Lisbon, Portugal
- Department of Bioengineering, Instituto Superior Técnico, Universidade de Lisboa, Lisbon, Portugal
- Associate Laboratory i4HB—Institute for Health and Bioeconomy at Instituto Superior Técnico, Universidade de Lisboa, Lisbon, Portugal
- Centre of Marine Sciences, University of Algarve, Faro, Portugal
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Recent Insights into Escherichia coli and Vibrio spp. Pathogenicity and Responses to Stress. Microorganisms 2021; 10:microorganisms10010038. [PMID: 35056488 PMCID: PMC8779644 DOI: 10.3390/microorganisms10010038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Accepted: 12/24/2021] [Indexed: 11/17/2022] Open
Abstract
The ubiquitous presence of microorganisms is largely attributed to their tremendous capacity to successfully adapt and survive in highly adverse environments [...].
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Zhang Y, Deng Y, Feng J, Hu J, Chen H, Guo Z, Su Y. LuxS modulates motility and secretion of extracellular protease in fish pathogen Vibrio harveyi. Can J Microbiol 2021; 68:215-226. [PMID: 34855458 DOI: 10.1139/cjm-2021-0311] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In this study, an in-frame deletion of the luxS gene was constructed to reveal the role of LuxS in the physiology and virulence of V. harveyi. The statistical analysis showed no significant differences in the growth ability, biofilm formation, antibiotic susceptibility, virulence by intraperitoneal injection, and the ability of V. harveyi to colonize the spleen and liver of the pearl gentian grouper between the wild-type (WT) and the luxS mutant. However, the deletion of luxS decreased the secretion of extracellular protease, while increased the ability of swimming and swarming. Simultaneously, a luxS-deleted mutant showed overproduction of lateral flagella, and an intact luxS complemented the defect. Since motility is flagella dependent, 16 of V. harveyi flagella biogenesis related genes were selected for further analysis. Based on quantitative real-time reverse transcription-PCR (qRT-PCR), the expression levels of these genes, including the polar flagella genes flaB, flhA, flhF, flhB, flhF, fliS, and flrA and the lateral flagella genes flgA, flgB, fliE, fliF, lafA, lafK, and motY, were significantly up-regulated in the ΔluxS: pMMB207 (ΔluxS+) strain as compared with the V. harveyi 345: pMMB207 (WT+) and C-ΔluxS strains during the early, mid-exponential, and stationary growth phase.
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Affiliation(s)
- Yaqiu Zhang
- South China Sea Fisheries Research Institute, 271781, Guangzhou, Guangdong, China;
| | - Yiqing Deng
- South China Sea Fisheries Research Institute, 271781, Guangzhou, Guangdong, China;
| | - Juan Feng
- South China Sea Fisheries Research Institute, 271781, Guangzhou, Guangdong, China;
| | - Jianmei Hu
- South China Sea Fisheries Research Institute, 271781, Guangzhou, Guangdong, China;
| | - Haoxiang Chen
- South China Sea Fisheries Research Institute, 271781, Guangzhou, Guangdong, China;
| | - Zhixun Guo
- South China Sea Fisheries Research Institute, 271781, Guangzhou, Guangdong, China;
| | - Youlu Su
- Zhongkai University of Agriculture and Engineering, 47894, Guangzhou, China, 510225;
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Islam MT, Nasreen T, Kirchberger PC, Liang KYH, Orata FD, Johura FT, Hussain NAS, Im MS, Tarr CL, Alam M, Boucher YF. Population Analysis of Vibrio cholerae in Aquatic Reservoirs Reveals a Novel Sister Species ( Vibrio paracholerae sp. nov.) with a History of Association with Humans. Appl Environ Microbiol 2021; 87:e0042221. [PMID: 34132593 PMCID: PMC8357300 DOI: 10.1128/aem.00422-21] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Accepted: 06/04/2021] [Indexed: 12/12/2022] Open
Abstract
Most efforts to understand the biology of Vibrio cholerae have focused on a single group, the pandemic-generating lineage harboring the strains responsible for all known cholera pandemics. Consequently, little is known about the diversity of this species in its native aquatic environment. To understand the differences in the V. cholerae populations inhabiting regions with a history of cholera cases and those lacking such a history, a comparative analysis of population composition was performed. Little overlap was found in lineage compositions between those in Dhaka, Bangladesh (where cholera is endemic), located in the Ganges Delta, and those in Falmouth, MA (no known history of cholera), a small coastal town on the United States east coast. The most striking difference was the presence of a group of related lineages at high abundance in Dhaka, which was completely absent from Falmouth. Phylogenomic analysis revealed that these lineages form a cluster at the base of the phylogeny for the V. cholerae species and were sufficiently differentiated genetically and phenotypically to form a novel species. A retrospective search revealed that strains from this species have been anecdotally found from around the world and were isolated as early as 1916 from a British soldier in Egypt suffering from choleraic diarrhea. In 1935, Gardner and Venkatraman unofficially referred to a member of this group as Vibrio paracholerae. In recognition of this earlier designation, we propose the name Vibrio paracholerae sp. nov. for this bacterium. Genomic analysis suggests a link with human populations for this novel species and substantial interaction with its better-known sister species. IMPORTANCE Cholera continues to remain a major public health threat around the globe. Understanding the ecology, evolution, and environmental adaptation of the causative agent (Vibrio cholerae) and tracking the emergence of novel lineages with pathogenic potential are essential to combat the problem. In this study, we investigated the population dynamics of Vibrio cholerae in an inland locality, which is known as endemic for cholera, and compared them with those of a cholera-free coastal location. We found the consistent presence of the pandemic-generating lineage of V. cholerae in Dhaka, where cholera is endemic, and an exclusive presence of a lineage phylogenetically distinct from other V. cholerae lineages. Our study suggests that this lineage represents a novel species that has pathogenic potential and a human link to its environmental abundance. The possible association with human populations and coexistence and interaction with toxigenic V. cholerae in the natural environment make this potential human pathogen an important subject for future studies.
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Affiliation(s)
| | - Tania Nasreen
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada
| | - Paul C. Kirchberger
- Department of Integrative Biology, University of Texas at Austin, Austin, Texas, USA
| | - Kevin Y. H. Liang
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada
| | - Fabini D. Orata
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada
| | - Fatema-Tuz Johura
- Infectious Diseases Division, International Centre for Diarrheal Disease Research, Bangladesh (icddr,b), Dhaka, Bangladesh
| | - Nora A. S. Hussain
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada
| | - Monica S. Im
- National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Cheryl L. Tarr
- National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Munirul Alam
- Infectious Diseases Division, International Centre for Diarrheal Disease Research, Bangladesh (icddr,b), Dhaka, Bangladesh
| | - Yann F. Boucher
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada
- Saw Swee Hock School of Public Health, National University of Singapore, Singapore
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Aunkham A, Suginta W. Probing the physiological roles of the extracellular loops of chitoporin from Vibrio campbellii. Biophys J 2021; 120:2124-2137. [PMID: 33812846 PMCID: PMC8390830 DOI: 10.1016/j.bpj.2021.03.034] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Revised: 03/11/2021] [Accepted: 03/19/2021] [Indexed: 12/20/2022] Open
Abstract
VhChiP, a sugar-specific porin found on the outer membrane of Vibrio campbellii, is responsible for the transport of chitooligosaccharides, allowing the bacterium to thrive in aquatic environments using chitin as a nutrient. We previously showed that VhChiP is composed of three identical subunits, each containing a 16-stranded β-barrel connected by eight extracellular loops and eight short periplasmic turns. This study is focused on the specific roles of three prominent extracellular loops of VhChiP-L2, L3, and L8. The deletion of L2 completely disrupted the L2-L2 interactions, thus destabilizing the protein trimers as well as the integrity of the secondary structure. The deletion of L3 caused a drastic loss in the binding affinity for sugar substrates because of the absence of a cluster of key amino acid residues that form the affinity sites. The removal of L8 induced pronounced gating, which is highly responsive to elevated potentials. Our data provide further information on the important roles of the three prominent loops of VhChiP: loop L2 maintains the trimeric structure and the integrity of secondary structure, loop L3 controls the binding affinity for sugar substrates, and loop L8 retains the stably open state of the channel.
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Affiliation(s)
- Anuwat Aunkham
- School of Biomolecular Science and Engineering (BSE), Vidyasirimedhi Institute of Science and Technology (VISTEC), Rayong, Thailand
| | - Wipa Suginta
- School of Biomolecular Science and Engineering (BSE), Vidyasirimedhi Institute of Science and Technology (VISTEC), Rayong, Thailand.
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