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Journal of Bacteriology Feb 2024Multicellular communities of adherent bacteria known as biofilms are often detrimental in the context of a human host, making it important to study their formation and... (Review)
Review
Multicellular communities of adherent bacteria known as biofilms are often detrimental in the context of a human host, making it important to study their formation and dispersal, especially in animal models. One such model is the symbiosis between the squid and the bacterium . Juvenile squid hatch aposymbiotically and selectively acquire their symbiont from natural seawater containing diverse environmental microbes. Successful pairing is facilitated by ciliary movements that direct bacteria to quiet zones on the surface of the squid's symbiotic light organ where forms a small aggregate or biofilm. Subsequently, the bacteria disperse from that aggregate to enter the organ, ultimately reaching and colonizing deep crypt spaces. Although transient, aggregate formation is critical for optimal colonization and is tightly controlled. studies have identified a variety of polysaccharides and proteins that comprise the extracellular matrix. Some of the most well-characterized matrix factors include the symbiosis polysaccharide (SYP), cellulose polysaccharide, and LapV adhesin. In this review, we discuss these components, their regulation, and other less understood biofilm contributors. We also highlight what is currently known about dispersal from these aggregates and host cues that may promote it. Finally, we briefly describe discoveries gleaned from the study of other isolates. By unraveling the complexities involved in 's control over matrix components, we may begin to understand how the host environment triggers transient biofilm formation and dispersal to promote this unique symbiotic relationship.
Topics: Animals; Humans; Aliivibrio fischeri; Biofilms; Bacterial Proteins; Adhesins, Bacterial; Decapodiformes; Symbiosis; Polysaccharides
PubMed: 38270381
DOI: 10.1128/jb.00370-23 -
Fish & Shellfish Immunology Nov 2023In this study, a strain (recorded as Y6) was isolated from the biofloc pool, its DNA was extracted for 16S rDNA sequencing and compared in the NCBI database, and it was...
In this study, a strain (recorded as Y6) was isolated from the biofloc pool, its DNA was extracted for 16S rDNA sequencing and compared in the NCBI database, and it was identified as Vibrio fortis. The V. fortis was activated, cultured, and artificially injected into Penaeus monodon to observe the symptoms and calculate the semi-lethal concentration (LC). It was found that the symptoms of the red leg, an empty stomach, and enlarged hepatopancreas of P. monodon after infection with V. fortis. The LC was 4.00 × 10, 2.24 × 10, 1.82 × 10, 1.41 × 10, 7.52 × 10 and 3.31 × 10 CFU/mL at 16, 24, 32, 48, 128, and 144 hpi, respectively. The K-B disk method was used to detect the sensitivity of V. fortis to various antibiotic drugs. V. fortis resisted Ampicillin, Piperacillin, Cefazolin, Cephalothin and Cefoxitin. Highly sensitive to Polymyxin B, Tobramycin, Gentamicin, Cefepime, Cefoperazone and Streptomycin. To explore the molecular response mechanism of V. fortis infection in P. monodon, the hepatopancreas of P. monodon infected with V. fortis at 24 and 48 hpi by transcriptome sequencing, and a total of 347 DEGs were obtained (214 up-regulated DEGs and 133 down-regulated DEGs). In the KEGG pathway enrichment analysis of DEGs, significant changes were found in genes and signaling pathways related to immune system and substance metabolism, including NOD-like receptor signaling pathways, Toll and Imd signaling pathways, C-type lectin receptor signaling pathways and pyruvate metabolism. This study initially revealed the immune response of P. monodon to V. fortis infection from the molecular level and provided a reference for further understanding of the study and control of the vibriosis of shrimp.
Topics: Animals; Transcriptome; Penaeidae; Virulence; Vibrio
PubMed: 37751788
DOI: 10.1016/j.fsi.2023.109097 -
Journal of Applied Microbiology Jul 2023Aquaculture, a noteworthy food production sector, is confronted with disease occurrences. Treatment of aquaculture pathogens with antibiotics is often rendered... (Review)
Review
Aquaculture, a noteworthy food production sector, is confronted with disease occurrences. Treatment of aquaculture pathogens with antibiotics is often rendered ineffective due to biofilm formation and the development of resistant strains. Marine ecosystems encompass unusual microorganisms that produce novel bioactive compounds, including agents that could be used as alternatives to antibiotics. Moreover, biomass and/or biomolecules associated with these microorganisms could act as feed supplements to enhance the overall health of aquaculture species' and improve water quality parameters. The present review summarizes the contents of studies on such marine microorganisms with the potential to be developed as agents for tackling bacterial diseases in the aquaculture segment. Bioactive compounds produced by marine bacteria are known to inhibit biofilm-associated infections mediated by their bactericidal properties (produced by Bacillus, Vibrio, Photobacterium, and Pseudoalteromonas species), surfactant activity (obtained from different species of Bacillus and Staphylococcus lentus), anti-adhesive activity (derived from Bacillus sp. and Brevibacterium sp.), and quorum sensing inhibition. Several marine fungal isolates capable of producing antibacterial agents have also been effective in inhibiting aquaculture-associated pathogens. Another strategy followed by investigators to reduce the severity of infections is the use of bacterial, yeast, and microalgae biomass as feed supplements, probiotics, and immunostimulants. In some cases, marine microalgae have been employed as sustainable alternatives to fish oil and fish meal without compromising on nutritional quality. Their inclusion in aquaculture feed has enhanced growth, favored better survival of cultured species, and improved water quality parameters. Marine microorganisms (by providing effective bioactive compounds and being used as feed supplements) could enable aquaculture practices to be more sustainable in the future.
Topics: Ecosystem; Aquaculture; Anti-Infective Agents; Bacillus; Vibrio; Anti-Bacterial Agents
PubMed: 37365690
DOI: 10.1093/jambio/lxad128 -
Food Research International (Ottawa,... Nov 2023There is little known about the growth and survival of naturally-occurring Vibrio parahaemolyticus in harvested raw shrimps. In this study, the fate of...
There is little known about the growth and survival of naturally-occurring Vibrio parahaemolyticus in harvested raw shrimps. In this study, the fate of naturally-occurring V. parahaemolyticus in post-harvest raw shrimps was investigated from 4℃ to 30℃ using real-time PCR combined with propidium monoazide (PMA-qPCR). The Baranyi-model was used to fit the growth and survival data. A square root model and non-linear Arrhenius model was then used to quantify the parameters derived from the Baranyi-model. The results showed that naturally-occurring V. parahaemolyticus were slowly inactivated at 4℃ and 7℃ with deactivation rates of 0.019 Log CFU/g/h and 0.025 Log CFU/g/h. Conversely, at 15, 20, 25, and 30 °C, the average maximum growth rates (μ) of naturally-occurring V. parahaemolyticus were determined to be 0.044, 0.105, 0.179 and 0.336 Log CFU/g/h, accompanied by the average lag phases (λ) of 15.5 h, 7.3 h, 4.4 h and 3.7 h. The validation metrics, A and B, for both the square root model and non-linear, indicating that the model had a good ability to predict the growth behavior of naturally-occurring V. parahaemolyticus in post-harvest raw shrimps. Furthermore, a comparative exploration between the growth of artificially contaminated V. parahaemolyticus in cooked shrimps and naturally-occurring V. parahaemolyticus in post-harvest raw shrimps revealed intriguing insights. While no substantial distinction in deactivation rates emerged at 4 °C and 7 °C (P > 0.05), a discernible disparity in growth rates was observable at 15 °C, 20 °C, 25 °C, and 30 °C, with the former surpassing the latter. Which indicated the risk of V. parahaemolyticus using models derived from cooked shrimps may be biased. Our study also unveiled a discernible seasonal effect. The μ and λ of V. parahaemolyticus in shrimps harvested in summer were similar to those harvested in autumn, while the initial and maximum bacterial concentration harvested in summer were higher than those harvested in autumn. This predictive microbiology model of naturally-occurring V. parahaemolyticus in raw shrimps provides relevance to modelling growth in situ.
Topics: Animals; Vibrio parahaemolyticus; Colony Count, Microbial; Food Microbiology; Seafood; Decapoda; Penaeidae
PubMed: 37803786
DOI: 10.1016/j.foodres.2023.113462 -
EcoSal Plus Dec 2023To preserve the integrity of their genome, bacteria rely on several genome maintenance mechanisms that are co-ordinated with the cell cycle. All members of the family... (Review)
Review
To preserve the integrity of their genome, bacteria rely on several genome maintenance mechanisms that are co-ordinated with the cell cycle. All members of the family have a bipartite genome consisting of a primary chromosome (Chr1) homologous to the single chromosome of other bacteria such as and a secondary chromosome (Chr2) acquired by a common ancestor as a plasmid. In this review, we present our current understanding of genome maintenance in , which is the best-studied model for bacteria with multi-partite genomes. After a brief overview on the diversity of genomic architecture, we describe the specific, common, and co-ordinated mechanisms that control the replication and segregation of the two chromosomes of . Particular attention is given to the unique checkpoint mechanism that synchronizes Chr1 and Chr2 replication.
Topics: DNA Replication; Bacterial Proteins; Chromosomes, Bacterial; Cell Cycle; Vibrio cholerae; Bacteria
PubMed: 38277776
DOI: 10.1128/ecosalplus.esp-0008-2022 -
Gut Microbes Dec 2023In many species, virulence is regulated by quorum sensing, which is regulated by a complex, multichannel, two-component phosphorelay circuit. Through this circuit,...
In many species, virulence is regulated by quorum sensing, which is regulated by a complex, multichannel, two-component phosphorelay circuit. Through this circuit, sensor kinases transmit sensory information to the phosphotransferase LuxU via a phosphotransfer mechanism, which in turn transmits the signal to the response regulator LuxO. For , type III secretion system 1 (T3SS1) is required for cytotoxicity, but it is unclear how quorum sensing regulates T3SS1 expression. Herein, we report that a hybrid histidine kinase, ArcB, instead of LuxU, and sensor kinase LuxQ and response regulator LuxO, collectively orchestrate T3SS1 expression in . Under high oxygen conditions, LuxQ can interact with ArcB directly and phosphorylates the Hpt domain of ArcB. The Hpt domain of ArcB phosphorylates the downstream response regulator LuxO instead of ArcA. LuxO then activates transcription of the T3SS1 gene cluster. Under hypoxic conditions, ArcB autophosphorylates and phosphorylates ArcA, whereas ArcA does not participate in regulating the expression of T3SS1. Our data provides evidence of an alternative regulatory path involving the quorum sensing phosphorelay and adds another layer of understanding about the environmental regulation of gene expression in .
Topics: Vibrio parahaemolyticus; Quorum Sensing; Type III Secretion Systems; Bacterial Proteins; Gastrointestinal Microbiome; Phosphotransferases; Gene Expression Regulation, Bacterial
PubMed: 37982663
DOI: 10.1080/19490976.2023.2281016 -
Cell Reports Nov 2023Vibrio cholerae is an aquatic bacterium that causes severe and potentially deadly diarrheal disease. Despite the impact on global health, our understanding of host...
Vibrio cholerae is an aquatic bacterium that causes severe and potentially deadly diarrheal disease. Despite the impact on global health, our understanding of host mucosal responses to Vibrio remains limited, highlighting a knowledge gap critical for the development of effective prevention and treatment strategies. Using a natural infection model, we combine physiological and single-cell transcriptomic studies to characterize conventionally reared adult zebrafish guts and guts challenged with Vibrio. We demonstrate that Vibrio causes a mild mucosal immune response characterized by T cell activation and enhanced antigen capture; Vibrio suppresses host interferon signaling; and ectopic activation of interferon alters the course of infection. We show that the adult zebrafish gut shares similarities with mammalian counterparts, including the presence of Best4 cells, tuft cells, and a population of basal cycling cells. These findings provide important insights into host-pathogen interactions and emphasize the utility of zebrafish as a natural model of Vibrio infection.
Topics: Animals; Cholera; Zebrafish; Vibrio cholerae; Intestines; Interferons; Mammals
PubMed: 37948182
DOI: 10.1016/j.celrep.2023.113407 -
Applied and Environmental Microbiology Oct 2023Cholera is a major public health problem in developing and underdeveloped countries; however, it remains of concern to developed countries such as Australia as...
Cholera is a major public health problem in developing and underdeveloped countries; however, it remains of concern to developed countries such as Australia as international travel-related or locally acquired cholera or diarrheal disease cases are still reported. Cholera is mainly caused by cholera toxin (CT) producing toxigenic O1 and O139 serogroup strains. While most toxigenic cases in Australia are thought to be caused by international-acquired infections, Australia has its own indigenous toxigenic and non-toxigenic O1 and non-O1, non-O139 (NOVC) strains. In Australia, in the 1970s and again in 2012, it was reported that south-east Queensland riverways were a reservoir for toxigenic strains that were linked to local cases. Further surveillance on environmental reservoirs, such as riverways, has not been reported in the literature in the last 10 years. Here we present data from sites previously related to outbreaks and surveillance sampling to detect the presence of using PCR in conjunction with MALDI-TOF and whole-genome sequencing. In this study, we were able to detect NOVC at all 10 sites with all sites having toxigenic non-O1, non-O139 strains. Among 133 NOVC isolates, 22 were whole-genome sequenced and compared with previously sequenced Australian O1 and NOVC strains. None of the samples tested grew toxigenic or non-toxigenic O1 or O139, responsible for epidemic disease. Since NOVC can be pathogenic, continuous surveillance is required to assist in theclinical and envir rapid identification of sources of any outbreaks and to assist public health authorities in implementing control measures. IMPORTANCE is a natural inhabitant of aquatic environments, both freshwater and seawater, in addition to its clinical significance as a causative agent of acute diarrhea and extraintestinal infections. Previously, both toxigenic and non-toxigenic, clinical, and environmental strains have been reported in Queensland, Australia. This study aimed to characterize recent surveillance of environmental NOVC strains isolated from Queensland River waterways to understand their virulence, antimicrobial resistance profile and to place genetic current strains from Australia in context with international strains. The findings from this study suggest the presence of unique toxigenic in Queensland river water systems that are of public health concern. Therefore, ongoing monitoring and genomic characterization of strains from the Queensland environment is important and would assist public health departments to track the source of cholera infection early and implement prevention strategies for future outbreaks. The genomics of environmental could assist us to understand the natural ecology and evolution of this bacterium in natural environments with respect to global warming and climate change.
Topics: Humans; Australia; Cholera; Queensland; Rivers; Travel-Related Illness; Vibrio cholerae
PubMed: 37800954
DOI: 10.1128/aem.00472-23 -
Proceedings of the National Academy of... Jul 2023ToxR, a transmembrane one-component signal transduction factor, lies within a regulatory cascade that results in the expression of ToxT, toxin coregulated pilus, and...
ToxR, a transmembrane one-component signal transduction factor, lies within a regulatory cascade that results in the expression of ToxT, toxin coregulated pilus, and cholera toxin. While ToxR has been extensively studied for its ability to activate or repress various genes in , here we present the crystal structures of the ToxR cytoplasmic domain bound to DNA at the and promoters. The structures confirm some predicted interactions, yet reveal other unexpected promoter interactions with implications for other potential regulatory roles for ToxR. We show that ToxR is a versatile virulence regulator that recognizes diverse and extensive, eukaryotic-like regulatory DNA sequences, that relies more on DNA structural elements than specific sequences for binding. Using this topological DNA recognition mechanism, ToxR can bind both in tandem and in a twofold inverted-repeat-driven manner. Its regulatory action is based on coordinated multiple binding to promoter regions near the transcription start site, which can remove the repressing H-NS proteins and prepares the DNA for optimal interaction with the RNA polymerase.
Topics: Vibrio cholerae; Transcription Factors; DNA-Binding Proteins; Virulence; Bacterial Proteins; DNA; Gene Expression Regulation, Bacterial
PubMed: 37428913
DOI: 10.1073/pnas.2304378120 -
Archives of Microbiology Nov 2023The marine bacteria of the Vibrionaceae family are significant from the point of view of their role in the marine geochemical cycle, as well as symbionts and... (Review)
Review
The marine bacteria of the Vibrionaceae family are significant from the point of view of their role in the marine geochemical cycle, as well as symbionts and opportunistic pathogens of aquatic animals and humans. The well-known pathogens of this group, Vibrio cholerae, V. parahaemolyticus, and V. vulnificus, are responsible for significant morbidity and mortality associated with a range of infections from gastroenteritis to bacteremia acquired through the consumption of raw or undercooked seafood and exposure to seawater containing these pathogens. Although generally regarded as susceptible to commonly employed antibiotics, the antimicrobial resistance of Vibrio spp. has been on the rise in the last two decades, which has raised concern about future infections by these bacteria becoming increasingly challenging to treat. Diverse mechanisms of antimicrobial resistance have been discovered in pathogenic vibrios, the most important being the membrane efflux pumps, which contribute to antimicrobial resistance and their virulence, environmental fitness, and persistence through biofilm formation and quorum sensing. In this review, we discuss the evolution of antimicrobial resistance in pathogenic vibrios and some of the well-characterized efflux pumps' contributions to the physiology of antimicrobial resistance, host and environment survival, and their pathogenicity.
Topics: Animals; Humans; Anti-Bacterial Agents; Vibrionaceae; Drug Resistance, Bacterial; Vibrio; Vibrio cholerae; Vibrio parahaemolyticus
PubMed: 38017151
DOI: 10.1007/s00203-023-03731-5