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Virulence Dec 2023Metals are nutrients essential for almost all lifeforms. Bacteria have evolved several mechanisms to overcome the metal restrictions imposed by the host. causes severe...
Metals are nutrients essential for almost all lifeforms. Bacteria have evolved several mechanisms to overcome the metal restrictions imposed by the host. causes severe threats to public health and significant economic losses in shrimp aquaculture. Herein, we report that ZrgA contributes to zinc acquisition in this pathogen. The operon to of encodes the putative Zn transporter ZrgABCDE, whose homologs are widely distributed in . RNA sequencing analysis revealed that modulates the transcriptome in response to Zn limitation. Genes in the Zinc uptake regulator (Zur) regulon are upregulated during Zn limitation, including three genes annotated to encode Zn-binding proteins. Significant upregulation of these three genes during Zn limitation was also confirmed by quantitative real-time PCR (qRT-PCR) analysis. However, only the mutants containing a () deletion exhibited impaired growth under Zn-deficient conditions, indicating that plays the predominant role in Zn acquisition. The deletion mutant displayed a false appearance of decreased swimming motility under Zn-deficient conditions, as revealed by the fact that the polar flagellar-related genes were not downregulated in the mutant. Moreover, deletion produced no noticeable impact on the swarming motility and virulence in mice. qRT-PCR analysis and β-galactosidase activity assays indicated that Zur negatively regulates expression in . Collectively, our findings suggest that ZrgA is required for Zn acquisition in and highlight the importance of detecting the expression of flagellar genes during analysis of motility of a mutant deficient in growth.
Topics: Animals; Mice; Vibrio parahaemolyticus; Zinc; Membrane Transport Proteins; Carrier Proteins; Transcriptome; Bacterial Proteins
PubMed: 36482737
DOI: 10.1080/21505594.2022.2156196 -
Environmental Microbiome Aug 2023Marine heat waves (MHWs) have increased in frequency and intensity worldwide, causing mass mortality of benthic organisms and loss of biodiversity in shallow waters. The...
Marine heat waves (MHWs) have increased in frequency and intensity worldwide, causing mass mortality of benthic organisms and loss of biodiversity in shallow waters. The Mediterranean Sea is no exception, with shallow populations of habitat-forming octocorals facing the threat of local extinction. The mesophotic zone, which is less affected by MHWs, may be of ecological importance in conservation strategies for these species. However, our understanding of the response of mesophotic octocoral holobionts to changes in seawater temperature remains limited. To address this knowledge gap, we conducted a study on an iconic Mediterranean octocoral, the red coral Corallium rubrum sampled at 60 m depth and 15 °C. We exposed the colonies to temperatures they occasionally experience (18 °C) and temperatures that could occur at the end of the century if global warming continues (21 °C). We also tested their response to extremely cold and warm temperatures (12 °C and 24 °C). Our results show a high tolerance of C. rubrum to a two-month long exposure to temperatures ranging from 12 to 21 °C as no colony showed signs of tissue loss, reduced feeding ability, stress-induced gene expression, or disruption of host-bacterial symbioses. At 24 °C, however, we measured a sharp decrease in the relative abundance of Spirochaetaceae, which are the predominant bacterial symbionts under healthy conditions, along with a relative increase in Vibrionaceae. Tissue loss and overexpression of the tumor necrosis factor receptor 1 gene were also observed after two weeks of exposure. In light of ongoing global warming, our study helps predict the consequences of MHWs on mesophotic coralligenous reefs and the biodiversity that depends on them.
PubMed: 37580830
DOI: 10.1186/s40793-023-00525-6 -
BioRxiv : the Preprint Server For... May 2024Marine bacteria experience fluctuations in osmolarity that they must adapt to, and most bacteria respond to high osmolarity by accumulating compatible solutes also known...
UNLABELLED
Marine bacteria experience fluctuations in osmolarity that they must adapt to, and most bacteria respond to high osmolarity by accumulating compatible solutes also known as osmolytes. The osmotic stress response and compatible solutes used by the coral and oyster pathogen were unknown. In this study, we showed that to alleviate osmotic stress biosynthesized glycine betaine (GB) and transported into the cell choline, GB, ectoine, dimethylglycine, and dimethylsulfoniopropionate, but not -inositol. -inositol is a stress protectant and a signaling molecule that is biosynthesized and used by algae. Bioinformatics identified -inositol ( ) catabolism clusters in and other and species. Growth pattern analysis demonstrated that utilized -inositol as a sole carbon source, with a short lag time of 3 h. An deletion mutant, which encodes an inositol dehydrogenase, was unable to grow on -inositol. Within the clusters were an MFS-type ( and an ABC-type ( transporter and analyses showed that both transported -inositol. IolG and IolA phylogeny among species showed different evolutionary histories indicating multiple acquisition events. Outside of , IolG was most closely related to IolG from a small group of fish and human pathogens and species. However, IolG from hypervirulent strains clustered with IolG from and divergently from and plant pathogens. The cluster was also present within and of which many species were associated with marine flora and fauna.
IMPORTANCE
Host associated bacteria such as encounter competition for nutrients and have evolved metabolic strategies to better compete for food. Emerging studies show that -inositol is exchanged in the coral-algae symbiosis, is likely involved in signaling, but is also an osmolyte in algae. The bacterial consumption of -inositol could contribute to a breakdown of the coral-algae symbiosis during thermal stress or disrupt the coral microbiome. Phylogenetic analyses showed that the evolutionary history of -inositol metabolism is complex, acquired multiple times in but acquired once in many bacterial plant pathogens. Further analysis also showed that a conserved cluster is prevalent among many marine species (commensals, mutualists, and pathogens) associated with marine flora and fauna, algae, sponges, corals, molluscs, crustaceans, and fish.
PubMed: 38766061
DOI: 10.1101/2024.01.16.575920 -
Microbiology Spectrum Aug 2023Empiric probiotics are commonly consumed by healthy individuals as a means of disease prevention, pathogen control, etc. However, controversy has existed for a long time...
Empiric probiotics are commonly consumed by healthy individuals as a means of disease prevention, pathogen control, etc. However, controversy has existed for a long time regarding the safety and benefits of probiotics. Here, two candidate probiotics, Lactiplantibacillus plantarum and Pediococcus acidilactici, which are antagonistic to and species , were tested on under conditions. In the bacterial community of Artemia nauplii, reduced the abundance of the genera and and significantly increased the abundance of species in a positive dosage-dependent manner, while higher and lower dosages of increased and decreased the abundance of the genus , respectively. Based on the liquid chromatography-mass spectrometry (LC-MS) and gas chromatography-mass spectrometry (GC-MS) analyses of the metabolite of and , pyruvic acid was used in an test to explain such selective antagonism; the results showed that pyruvic acid was conducive or suppressive to V. parahaemolyticus and beneficial to A. hydrophila. Collectively, the results of this study demonstrate the selective antagonism of probiotics on the bacterial community composition of aquatic organisms and the associated pathogens. Over the last decade, the common preventive method for controlling potential pathogens in aquaculture has been the use of probiotics. However, the mechanisms of probiotics are complicated and mostly undefined. At present, less attention has been paid to the potential risks of probiotic use in aquaculture. Here, we investigated the effects of two candidate probiotics, and , on the bacterial community of Artemia nauplii and the interactions between these two candidate probiotics and two pathogens, and species. The results demonstrated the selective antagonism of probiotics on the bacterial community composition of an aquatic organism and its associated pathogens. This research contributes to providing a basis and reference for the long-term rational use of probiotics and to reducing the inappropriate use of probiotics in aquaculture.
Topics: Humans; Animals; Pediococcus acidilactici; Aeromonas; Artemia; Pyruvic Acid; Vibrio; Probiotics
PubMed: 37428079
DOI: 10.1128/spectrum.00533-23 -
Emerging Infectious Diseases Sep 2023In Haiti in 2017, the prevalence of serum vibriocidal antibody titers against Vibrio cholerae serogroup O1 among adults was 12.4% in Cerca-la-Source and 9.54% in...
In Haiti in 2017, the prevalence of serum vibriocidal antibody titers against Vibrio cholerae serogroup O1 among adults was 12.4% in Cerca-la-Source and 9.54% in Mirebalais, suggesting a high recent prevalence of infection. Improved surveillance programs to monitor cholera and guide public health interventions in Haiti are necessary.
Topics: Adult; Humans; Haiti; Seroepidemiologic Studies; Cholera; Vibrio cholerae O1; Public Health
PubMed: 37610182
DOI: 10.3201/eid2909.230401 -
Nature Communications Aug 2023Although enzyme catalysis is typified by high specificity, enzymes can catalyze various substrates (substrate promiscuity) and/or different reaction types (catalytic...
Although enzyme catalysis is typified by high specificity, enzymes can catalyze various substrates (substrate promiscuity) and/or different reaction types (catalytic promiscuity) using a single active site. This interesting phenomenon is widely distributed in enzyme catalysis, with both fundamental and applied importance. To date, the mechanistic understanding of enzyme promiscuity is very limited. Herein, we report the structural mechanism underlying the substrate and catalytic promiscuity of Vibrio dual lipase/transferase (VDLT). Crystal structures of the VDLT from Vibrio alginolyticus (ValDLT) and its fatty acid complexes were solved, revealing prominent structural flexibility. In particular, the "Ser-His-Asp" catalytic triad machinery of ValDLT contains an intrinsically flexible oxyanion hole. Analysis of ligand-bound structures and mutagenesis showed that the flexible oxyanion hole and other binding residues can undergo distinct conformational changes to facilitate substrate and catalytic promiscuity. Our study reveals a previously unknown flexible form of the famous catalytic triad machinery and proposes a "catalytic site tuning" mechanism to expand the mechanistic paradigm of enzyme promiscuity.
Topics: Catalytic Domain; Lipase; Transferases; Catalysis; Vibrio; Substrate Specificity
PubMed: 37558668
DOI: 10.1038/s41467-023-40455-y -
Biomedical and Environmental Sciences :... Oct 2023This study aimed to investigate whether the VCA0560 gene acts as an active diguanylate cyclase (DGC) in and how its transcription is regulated by Fur and HapR.
OBJECTIVE
This study aimed to investigate whether the VCA0560 gene acts as an active diguanylate cyclase (DGC) in and how its transcription is regulated by Fur and HapR.
METHODS
The roles of VCA0560 was investigated by utilizing various phenotypic assays, including colony morphological characterization, crystal violet staining, Cyclic di-GMP (c-di-GMP) quantification, and swimming motility assay. The regulation of the VCA0560 gene by Fur and HapR was analyzed by luminescence assay, electrophoretic mobility shift assay, and DNase I footprinting.
RESULTS
VCA0560 gene mutation did not affect biofilm formation, motility, and c-di-GMP synthesis in , and its overexpression remarkably enhanced biofilm formation and intracellular c-di-GMP level but reduced motility capacity. The transcription of the VCA0560 gene was directly repressed by Fur and the master quorum sensing regulator HapR.
CONCLUSION
Overexpressed VCA0560 functions as an active DGC in , and its transcription is repressed by Fur and HapR.
Topics: Vibrio cholerae; Biofilms; Quorum Sensing; Mutation; Gene Expression Regulation, Bacterial; Bacterial Proteins
PubMed: 37932063
DOI: 10.3967/bes2023.080 -
MicrobiologyOpen Oct 2023Rifampicin resistance, which is genetically linked to mutations in the RNA polymerase β-subunit gene rpoB, has a global impact on bacterial transcription and cell...
Rifampicin resistance, which is genetically linked to mutations in the RNA polymerase β-subunit gene rpoB, has a global impact on bacterial transcription and cell physiology. Previously, we identified a substitution of serine 522 in RpoB (i.e., RpoB ) conferring rifampicin resistance to Vibrio vulnificus, a human food-borne and wound-infecting pathogen associated with a high mortality rate. Transcriptional and physiological analysis of V. vulnificus expressing RpoB showed increased basal transcription of stress-related genes and global virulence regulators. Phenotypically these transcriptional changes manifest as disturbed osmo-stress responses and toxin-associated hypervirulence as shown by reduced hypoosmotic-stress resistance and enhanced cytotoxicity of the RpoB strain. These results suggest that RpoB-linked rifampicin resistance has a significant impact on V. vulnificus survival in the environment and during infection.
Topics: Humans; Rifampin; Vibrio vulnificus; Bacterial Proteins; Mutation; Virulence; DNA-Directed RNA Polymerases
PubMed: 37877661
DOI: 10.1002/mbo3.1379 -
Archives of Microbiology Dec 2023Vibrio parahaemolyticus is a significant cause of seafood-associated gastroenteritis and pestilence in aquaculture worldwide. Despite extensive research, strategies for...
Vibrio parahaemolyticus is a significant cause of seafood-associated gastroenteritis and pestilence in aquaculture worldwide. Despite extensive research, strategies for protein depletion in this pathogen remain limited. Herein, we constructed a new CRISPR interference (CRISPRi) system for gene repression based on the combination of a shuttle vector pVv3 and the nuclease-null Cas9 variant (dead Cas9, or dCas9) from Streptococcus pyrogens. This CRISPRi is induced by adding both IPTG and arabinose. We showed that gene repression is scalable via the use of multiple sgRNAs. We also demonstrated that this gene repression can be precisely tuned by adjusting the amount of two different inducers and can be reversed by removing the inducers. This system provides a simple approach for selective gene repression on a genome-wide scale in V. parahaemolyticus. Application of this system will dramatically accelerate investigations of this bacterium, including studies of physiology, pathogenesis, and drug target discovery.
Topics: Vibrio parahaemolyticus; RNA, Guide, CRISPR-Cas Systems; Aquaculture; Arabinose; Drug Discovery
PubMed: 38147133
DOI: 10.1007/s00203-023-03770-y -
Infection, Genetics and Evolution :... Aug 2023Diarrheal cases caused by non-toxigenic Vibrio cholerae have been reported globally. Lineages L3b and L9, characterized as ctxAB-negative and tcpA-positive (CNTP), pose...
Diarrheal cases caused by non-toxigenic Vibrio cholerae have been reported globally. Lineages L3b and L9, characterized as ctxAB-negative and tcpA-positive (CNTP), pose the highest risk and have caused long-term epidemics in different regions worldwide. From 2001 to 2018, two waves (2001-2012 and 2013-2018) of epidemic caused by non-toxigenic V. cholerae occurred in the developed city of Hangzhou, China. In this study, through the integrated analysis of 207 genomes of Hangzhou isolates from these two waves (119 and 88) and 1573 publicly available genomes, we showed that L3b and L9 lineages together caused the second wave as had happened in the first wave, but the dominant lineage shifted from L3b (first wave: 69%) to L9 (second wave: 50%). We further found that the genotype of a key virulence gene, tcpF, in the L9 lineage during the second wave shifted to type I, which may have enhanced bacterial colonization in humans and potentially promoted the pathogenic lineage shift. Moreover, we found that 21% of L3b and L9 isolates had changed to predicted cholera toxin producers, providing evidence that gain of complete CTXφ-carrying ctxAB genes, rather than ctxAB gain in pre-CTXφ-carrying isolates, led to the transition. Taken together, our findings highlight the possible public health risk associated with L3b and L9 lineages due to their potential to cause long-term epidemics and turn into high-virulent cholera toxin producers, which necessitates a more comprehensive and unbiased sampling in further disease control efforts.
Topics: Humans; Vibrio cholerae; Cholera Toxin; Metagenomics; Public Health; Virulence; Cholera
PubMed: 37146742
DOI: 10.1016/j.meegid.2023.105441