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Proceedings of the National Academy of... May 2021Bacterial cells can self-organize into structured communities at fluid-fluid interfaces. These soft, living materials composed of cells and extracellular matrix are...
Bacterial cells can self-organize into structured communities at fluid-fluid interfaces. These soft, living materials composed of cells and extracellular matrix are called pellicles. Cells residing in pellicles garner group-level survival advantages such as increased antibiotic resistance. The dynamics of pellicle formation and, more generally, how complex morphologies arise from active biomaterials confined at interfaces are not well understood. Here, using as our model organism, a custom-built adaptive stereo microscope, fluorescence imaging, mechanical theory, and simulations, we report a fractal wrinkling morphogenesis program that differs radically from the well-known coalescence of wrinkles into folds that occurs in passive thin films at fluid-fluid interfaces. Four stages occur: growth of founding colonies, onset of primary wrinkles, development of secondary curved ridge instabilities, and finally the emergence of a cascade of finer structures with fractal-like scaling in wavelength. The time evolution of pellicle formation depends on the initial heterogeneity of the film microstructure. Changing the starting bacterial seeding density produces three variations in the sequence of morphogenic stages, which we term the bypass, crystalline, and incomplete modes. Despite these global architectural transitions, individual microcolonies remain spatially segregated, and thus, the community maintains spatial and genetic heterogeneity. Our results suggest that the memory of the original microstructure is critical in setting the morphogenic dynamics of a pellicle as an active biomaterial.
Topics: Biofilms; Biomechanical Phenomena; Computer Simulation; Fractals; Genetic Heterogeneity; Models, Biological; Optical Imaging; Vibrio cholerae
PubMed: 33972433
DOI: 10.1073/pnas.2023504118 -
Environmental Microbiology Oct 2022The Splendidus clade is the largest clade in Vibrionaceae, and its members are often related to mortality of marine animals with huge economic losses. The molecular...
The Splendidus clade is the largest clade in Vibrionaceae, and its members are often related to mortality of marine animals with huge economic losses. The molecular bases of their pathogenicity and virulence, however, remain largely unknown. In particular, the complete genome sequences of the Splendidus clade species are rarely registered, which is one of the obstacles to predict core and/or unique genes responsible for their adaptation and pathogenicity, and to perform a fine scale meta-transcriptome during bacterial infection to their hosts. In this study, we obtained the complete genomes of all type strains in the Splendidus clade and revealed that (1) different genome sizes (4.4-5.9 Mb) with V. lentus the biggest and most of them had several big plasmids, likely because of the different features on mobilome elements; (2) the Splendidus clade consists of 19 species except V. cortegadensis, and 3 sub-clades (SC) were defined with the 15 most closely related members as SC1; (3) different carbohydrate degradation preferences may be the result of environmental adaptation; and (4) a broad prediction of virulence factors (VFs) revealed core and species unique VF genes.
Topics: Animals; Carbohydrates; Evolution, Molecular; Genome, Bacterial; Phylogeny; Vibrionaceae; Virulence; Virulence Factors; Genome
PubMed: 36106979
DOI: 10.1111/1462-2920.16209 -
Applied and Environmental Microbiology Feb 2018and are naturally occurring estuarine bacteria and are the leading causes of seafood-associated infections and mortality in the United States. Though...
and are naturally occurring estuarine bacteria and are the leading causes of seafood-associated infections and mortality in the United States. Though multiple-antibiotic-resistant and strains have been reported, resistance patterns in vibrios are not as well documented as those of other foodborne bacterial pathogens. Salinity relaying (SR) is a postharvest processing (PHP) treatment to reduce the abundances of these pathogens in shellfish harvested during the warmer months. The purpose of this study was to evaluate the antimicrobial susceptibility (AMS), pathogenicity, and genetic profiles of and recovered from oysters during an oyster relay study. Isolates ( [ = 296] and [ = 94]) were recovered from oysters before and during the 21-day relaying study to detect virulence genes ( and ) and genes correlated with virulence () using multiplex quantitative PCR (qPCR). AMS to 20 different antibiotics was investigated using microbroth dilution, and pulsed-field gel electrophoresis (PFGE) was used to study the genetic profiles of the isolates. Twenty percent of isolates were , while 1 and 2% of were and , respectively. More than 77% of the isolates and 30% of the isolates were resistant to at least one antimicrobial. Forty-eight percent of and 8% of isolates were resistant to two or more antimicrobials. All isolates demonstrated a high genetic diversity, even among those isolated from the same site and having a similar AMS profile. No significant effects of the relaying process on AMS, virulence genes, or PFGE profiles of and were observed. Analysis of the antibiotic resistance profiles of and isolated from oysters during this study indicated that more than 48% of isolates were resistant to two or more antimicrobials, including those recommended by the CDC for treating infections. Also, the isolates showed high MICs for some of the infection treatment antibiotics. Monitoring of AMS profiles of this bacterium is important to ensure optimal treatment of infections and improve food safety. Our study showed no significant differences in the AMS profiles of ( = 0.26) and ( = 0.23) isolated from the oysters collected before versus after relaying. This suggests that the salinity of the relaying sites did not affect the AMS profiles of the isolates, although it did reduce the numbers of these bacteria in oysters (S. Parveen et al., J Food Sci 82:484-491, 2017, https://doi.org/10.1111/1750-3841.13584).
Topics: Animals; Anti-Bacterial Agents; Bacterial Proteins; Colony Count, Microbial; Drug Resistance, Multiple, Bacterial; Food Handling; Food Safety; Genetic Variation; Microbial Sensitivity Tests; Ostreidae; Polymerase Chain Reaction; Salinity; Shellfish; Vibrio Infections; Vibrio parahaemolyticus; Vibrio vulnificus; Virulence
PubMed: 29150510
DOI: 10.1128/AEM.01790-17 -
Advances in Experimental Medicine and... 2023One of the best studied aspects of pathogenic Vibrios are the virulence cascades that lead to the production of virulence factors and, ultimately, clinical outcomes. In...
One of the best studied aspects of pathogenic Vibrios are the virulence cascades that lead to the production of virulence factors and, ultimately, clinical outcomes. In this chapter, we will examine the regulation of Vibrio virulence gene networks from a structural and biochemical perspective. We will discuss the recent research into the numerous proteins that contribute to regulating virulence in Vibrio spp such as quorum sensing regulator HapR, the transcription factors AphA and AphB, or the virulence regulators ToxR and ToxT. We highlight how insights gained from these studies are already illuminating the basic molecular mechanisms by which the virulence cascade of pathogenic Vibrios unfold and contend that understanding how protein interactions contribute to the host-pathogen communications will enable the development of new antivirulence compounds that can effectively target these pathogens.
Topics: Trans-Activators; Virulence; Gene Regulatory Networks; Bacterial Proteins; Vibrio cholerae; Vibrio; Gene Expression Regulation, Bacterial
PubMed: 36792881
DOI: 10.1007/978-3-031-22997-8_14 -
Current Microbiology Mar 2018A Gram-reaction negative, aerobic, motile, non-pigmented and rod-shaped bacterium, designated as 168GH5-2-16, was isolated from seawater Jeju island. Phylogenetic...
A Gram-reaction negative, aerobic, motile, non-pigmented and rod-shaped bacterium, designated as 168GH5-2-16, was isolated from seawater Jeju island. Phylogenetic analysis based on 16S rRNA gene sequence comparison revealed that the strain formed a distinct lineage within the genus Vibrio and was most closely related to Vibrio variabilis R-40492 (96.0%). The DNA G+C content was 49.3 mol%. The major polar lipids were phosphatidylethanolamine (PE) and phosphatidylglycerol (PG). The predominant quinone was ubiquinone-8 (Q-8). The major fatty acids were C, summed feature 3 (comprising C ω7c/C ω6c) and summed feature 8 (C ω7c/C ω6c) supported the affiliation of 168GH5-2-16 to the genus Vibrio. Moreover, the physiological, biochemical, and taxonomic analysis allowed the phenotypic and genotypic differentiation of strain 168GH5-2-16 from the recognized species of the genus Vibrio. Therefore, strain 168GH5-2-16 represents a novel species of the genus Vibrio, for which the name Vibrio hannami sp. nov. is proposed, with the type strain 168GH5-2-16 (=KACC 19277 = DSM105032).
Topics: Bacterial Typing Techniques; Base Composition; DNA, Bacterial; DNA, Ribosomal; Fatty Acids; Phylogeny; RNA, Ribosomal, 16S; Seawater; Vibrio
PubMed: 29090323
DOI: 10.1007/s00284-017-1376-x -
Journal of Applied Microbiology Jul 2020Several virulence factors of three new Photobacterium species: Photobacterium toruni, Photobacterium malacitanum and Photobacterium andalusiense associated with diseases...
AIMS
Several virulence factors of three new Photobacterium species: Photobacterium toruni, Photobacterium malacitanum and Photobacterium andalusiense associated with diseases of cultured redbanded seabream (Pagrus auriga) were studied. The exoenzymatic activities, adherence and cytotoxic capabilities, and iron-uptake mechanisms were determined both in bacterial extracellular products (ECP) and whole bacterial cells. The histopathology damages provoked on redbanded seabream by the ECP was also studied.
METHODS AND RESULTS
The highest exoenzymatic activities of the ECP were alkaline- and acid-phosphatase, phosphohydrolase and lipase. The ECP were strongly lethal for fish at 4-96 h post-inoculation (p.i). Histological changes were evident at 96 hpi of ECP, affecting head kidney, splenic parenchyma and heart. Cytotoxicity assays, on three fish lines and one human cell line, were conducted using whole bacterial cells and their ECP. The new species tested were cytotoxic only for fish cell lines using whole bacterial cells. Bacterial adherence showed an adherence index moderate on CHSE-214 cell line. All strains showed variable haemolytic activity, and were able to grow under iron-limiting conditions, although the CAS reactivitiy was very low. However, all strains produced high amounts of extracelullar citrate that could be used as iron carrier, and use haem as iron source, except the P. toruni strains because a deletion in the genomic region encoding this ability in all Vibrionaceae members.
CONCLUSIONS
The toxic activity of the bacterial ECPs was thermolabile, and not associated with their thermoresistant lipopolysaccharide content. The virulence of the strains tested could not be related to the haemolytic activity. Iron uptake could be based on the use of endogenous citrate as iron carrier and P. toruni lacks the ability to use haem as iron source.
SIGNIFICANCE AND IMPACT OF THE STUDY
The study analyses for the first time the virulence properties of three new species of Photobacterium pathogenic for fish.
Topics: Animals; Aquaculture; Cell Line; Fish Diseases; Gram-Negative Bacterial Infections; Humans; Photobacterium; Sea Bream; Virulence; Virulence Factors
PubMed: 31505106
DOI: 10.1111/jam.14437 -
Journal of Applied Microbiology Feb 2022To investigate the relationships between individual health status of oysters, particularly with regard to parasitic infection, and variability in abundance of...
AIMS
To investigate the relationships between individual health status of oysters, particularly with regard to parasitic infection, and variability in abundance of human-pathogenic Vibrio species.
METHODS AND RESULTS
Aquacultured eastern oysters, Crassostrea virginica, were analysed individually for infection by the protozoan parasite Perkinsus marinus through quantitative PCR, and total Vibrio vulnificus and total and pathogenic Vibrio parahaemolyticus abundance was assessed using a most probable number (MPN)-qPCR approach. Additionally, perspective on general oyster health and other parasitic infections was obtained through histopathology. Perkinsus marinus infection and human-pathogenic Vibrio species levels were not correlated, but through histology, analyses revealed that oysters infected by Haplosporidium nelsoni harboured more V. vulnificus.
CONCLUSIONS
The highly prevalent parasite P. marinus had little influence on human-pathogenic Vibrio species levels in eastern oysters, but the less prevalent parasite, H. nelsoni, may influence V. vulnificus levels, highlighting the potential nuances of within-oyster dynamics of Vibrio species.
SIGNIFICANCE AND IMPACT OF THE STUDY
Human-pathogenic bacteria continue to be a concern to the oyster industry and causes for individual oyster variation in bacterial levels remain unknown. The major oyster pathogen P. marinus does not appear to affect levels of these bacteria within oysters, suggesting that other factors may influence Vibrio spp. levels in oysters.
Topics: Animals; Crassostrea; Humans; Ostreidae; Seafood; Vibrio parahaemolyticus; Vibrio vulnificus
PubMed: 34487403
DOI: 10.1111/jam.15287 -
International Journal of Systematic and... Jun 2023Strain 020920N was isolated from the estuary of the Kaeda river in the Miyazaki prefecture in Japan. Phylogenetic analysis based on the 16S rRNA gene showed the strain's...
Strain 020920N was isolated from the estuary of the Kaeda river in the Miyazaki prefecture in Japan. Phylogenetic analysis based on the 16S rRNA gene showed the strain's close evolutionary relationship with bacteria from the genus , in the family . Phenotypic and chemotaxonomic features of the strain were investigated. Whole genome sequencing revealed that the strain 020920N genome consists of two chromosomes and a plasmid, for a total of 5.52 Mbp. Calculations of whole genome average nucleotide identity and phylogenetic analysis based on the whole genome sequence showed that the strain represents a new species in the genus , for which we propose the name sp. nov. with the type strain 020920N (=LMG 32507=JCM 34978).
Topics: Sequence Analysis, DNA; Seawater; Fatty Acids; Estuaries; Rivers; Phylogeny; RNA, Ribosomal, 16S; Japan; DNA, Bacterial; Bacterial Typing Techniques; Base Composition; Vibrionaceae
PubMed: 37358383
DOI: 10.1099/ijsem.0.005946 -
Evolutionary Model of Cluster Divergence of the Emergent Marine Pathogen : From Genotype to Ecotype.MBio Feb 2019, an opportunistic pathogen, is the causative agent of a life-threatening septicemia and a rising problem for aquaculture worldwide. The genetic factors that...
, an opportunistic pathogen, is the causative agent of a life-threatening septicemia and a rising problem for aquaculture worldwide. The genetic factors that differentiate its clinical and environmental strains remain enigmatic. Furthermore, clinical strains have emerged from every clade of In this work, we investigated the underlying genomic properties and population dynamics of the species from an evolutionary and ecological point of view. Genome comparisons and bioinformatic analyses of 113 isolates indicate that the population of is made up of four different clusters. We found evidence that recombination and gene flow between the two largest clusters (cluster 1 [C1] and C2) have drastically decreased to the point where they are diverging independently. Pangenome and phenotypic analyses showed two markedly different lifestyles for these two clusters, indicating commensal (C2) and bloomer (C1) ecotypes, with differences in carbohydrate utilization, defense systems, and chemotaxis, among other characteristics. Nonetheless, we identified frequent intra- and interspecies exchange of mobile genetic elements (e.g., antibiotic resistance plasmids, novel "chromids," or two different and concurrent type VI secretion systems) that provide high levels of genetic diversity in the population. Surprisingly, we identified strains from both clusters in the mucosa of aquaculture species, indicating that manmade niches are bringing strains from the two clusters together. We propose an evolutionary model of that could be broadly applicable to other pathogenic vibrios and facultative bacterial pathogens to pursue strategies to prevent their infections and emergence. is an emergent marine pathogen and is the cause of a deadly septicemia. However, the genetic factors that differentiate its clinical and environmental strains and its several biotypes remain mostly enigmatic. In this work, we investigated the underlying genomic properties and population dynamics of the species to elucidate the traits that make these strains emerge as a human pathogen. The acquisition of different ecological determinants could have allowed the development of highly divergent clusters with different lifestyles within the same environment. However, we identified strains from both clusters in the mucosa of aquaculture species, indicating that manmade niches are bringing strains from the two clusters together, posing a potential risk of recombination and of emergence of novel variants. We propose a new evolutionary model that provides a perspective that could be broadly applicable to other pathogenic vibrios and facultative bacterial pathogens to pursue strategies to prevent their infections.
Topics: Aquaculture; Aquatic Organisms; Cluster Analysis; Computational Biology; Ecotype; Evolution, Molecular; Gene Flow; Gene Transfer, Horizontal; Genetic Variation; Genome, Bacterial; Genotype; Phenotype; Recombination, Genetic; Vibrio vulnificus
PubMed: 30782660
DOI: 10.1128/mBio.02852-18 -
Applied and Environmental Microbiology Feb 2017Vibrio species are widely distributed in warm estuarine and coastal environments, and they can infect humans through the consumption of raw and mishandled contaminated...
UNLABELLED
Vibrio species are widely distributed in warm estuarine and coastal environments, and they can infect humans through the consumption of raw and mishandled contaminated seafood. In this study, we aimed to isolate and observe the distribution of enteropathogenic Vibrio spp. from environments of the southern coast of South Korea over a season cycle. A total of 10,983 isolates of Vibrio spp. were obtained from tidal water and mud samples over a 1-year period from five sampling sites along the southwest coast of South Korea. We found that Vibrio alginolyticus (n = 6,262) and Vibrio parahaemolyticus (n = 1,757) were ubiquitous in both tidal water and mud year round, whereas Vibrio cholerae (n = 24) and Vibrio vulnificus (n = 130) were seasonally specific to summer. While all V. cholerae isolates were nontoxigenic (non-O1 and non-O139), more than 88% of V. vulnificus isolates possessed the virulence factor elastolytic protease (encoded by vvp). Interestingly, V. parahaemolyticus, which was omnipresent in all seasons, contained the virulence factors thermostable direct hemolysin (encoded by tdh) and thermostable direct hemolysin-related hemolysin (encoded by trh) in larger amounts in June (29 trh-positive strains) and September (14 tdh-, 36 trh-, and 12 tdh- and trh-positive strains) than in December (4 trh-positive strains) and February (3 tdh-positive strains), and virulence factors were absent from isolates detected in April. To understand why virulence factors were detected only in the warm season and were absent in the cold season although the locations are static, long-term monitoring and particularly seasonal study are necessary.
IMPORTANCE
The presence of enteropathogenic Vibrio species (Vibrio cholerae, Vibrio parahaemolyticus, and Vibrio vulnificus), which cause acute diarrheal infection, septicemia, and wound infections upon ingestion through food and water, is usually associated with temperature. The World Health Organization (WHO) has estimated that there are 1.4 to 4.3 million cases and 28,000 to 142,000 deaths per year worldwide caused by cholera disease. In South Korea alone, consumption is as much as 52.4 kg of fish and shellfish per year per capita. Our findings suggested that seasonally specific acceleration of these possible pathogenic Vibrio spp. may threaten seafood safety and increase the risk of illness in South Korea, where local people consume raw fish during warmer months.
Topics: Genotype; Geologic Sediments; Republic of Korea; Seasons; Seawater; Vibrio; Virulence
PubMed: 27836844
DOI: 10.1128/AEM.02680-16