Search results for "vibrio"
showing 10 items of 233 documents
Vibrio pelagius: differences of the type strain deposited at various culture collections.
2000
A critical evaluation of published and own taxonomic and phylogenetic studies on Vibrio pelagius showed substantial diversity of strains received as type strains from various Culture Collections. The comparison of data based upon 16S rRNA sequence analyses, earlier genomic DNA-DNA similarity studies as well as physiological investigations and the original description indicate that Vibrio pelagius strains CECT 4202T and ATCC 25916T really represent the originally described type species whereas strains NCIMB 1900T and CIP 102762T highly likely are representatives of Vibrio natriegens.
Genome size reduction through multiple events of gene disintegration in Buchnera APS
2001
The evolution of the endosymbiont Buchnera during its adaptation to intracellular life involved a massive reduction in its genome. By comparing the orthologous genes of Buchnera, Escherichia coli and Vibrio cholerae, we show that the minimal genome size of Buchnera arose from multiple events of gene disintegration dispersed over the whole genome. The elimination of the genes was a continuous process that began with gene inactivation and progressed until the DNA corresponding to the pseudogenes were completely deleted.
Phylogeny and life cycle of the zoonotic pathogen Vibrio vulnificus
2020
Vibrio vulnificus is a zoonotic pathogen able to cause diseases in humans and fish that occasionally result in sepsis and death. Most reviews about this pathogen (including those related to its ecology) are clearly biased towards its role as a human pathogen, emphasizing its relationship with oysters as its main reservoir, the role of the known virulence factors as well as the clinic and the epidemiology of the human disease. This review tries to give to the reader a wider vision of the biology of this pathogen covering aspects related to its phylogeny and evolution and filling the gaps in our understanding of the general strategies that V. vulnificus uses to survive outside and inside its …
Evaluation of genotypic and phenotypic methods to distinguish clinical from environmental Vibrio vulnificus strains.
2009
ABSTRACT Vibrio vulnificus is a heterogeneous bacterial species that comprises virulent and avirulent strains from environmental and clinical sources that have been grouped into three biotypes. To validate the typing methods proposed to distinguish clinical from environmental isolates, we performed phenotypic (API 20E, API 20NE, and BIOLOG tests) and genetic (ribotyping and DNA polymorphism at several loci) studies with a large strain collection representing different biotypes, origins, and host ranges. No phenotypic method was useful for biotyping or grouping strains with regard to the origin of an isolate, and only the BIOLOG system was reliable for identifying the strains at the species …
Genome-Wide SNP-Genotyping Array to Study the Evolution of the Human Pathogen Vibrio vulnificus Biotype 3
2014
Vibrio vulnificus is an aquatic bacterium and an important human pathogen. Strains Of V. vulnificus are classified into three different biotypes. The newly emerged biotype 3 has been found to be clonal and restricted to Israel. In the family Vibrionaceae , horizontal gene transfer is the main mechanism responsible for the emergence of new pathogen groups. To better understand the evolution of the bacterium, and in particular to trace the evolution of biotype 3, we performed genome-wide SNP genotyping of 254 clinical and environmental V. vulnificus isolates with worldwide distribution recovered over a 30-year period, representing all phylogeny groups. A custom single-nucleotide polymorphism …
Ecotoxicity assessment of boreal lake sediments affected by metal mining: Sediment quality triad approach complemented with metal bioavailability and…
2019
Highlights • Ecological risk assessment of metal-contaminated boreal lakes and sediments. • Sediment Quality Triad complemented with bioavailability and body residue studies. • Toxicity studies for natural sediments with several organisms and endpoints • Adverse effects observed. High variation on results between different methods. • Standard toxicity tests not suitable for testing, too low pH hampers the results. There are several methods for studying metal-contaminated freshwater sediments, but more information is needed on which methods to include in ecological risk assessment. In this study, we compliment the traditional Sediment Quality Triad (SQT) approach – including information on c…
Ecotoxicity of sediments in rivers: Invertebrate community, toxicity bioassays and the toxic unit approach as complementary assessment tools
2015
The determination of the real toxicity of sediments in aquatic ecosystems is challenging and necessary for an appropriate risk assessment. Different approaches have been developed and applied over the last several decades. Currently, the joint implementation of chemical, ecological and toxicological tools is recommended for an appropriate and successful toxicity risk assessment. We chose the combination of the toxic unit approach with acute pore water tests (Vibrio fischeri, Pseudokirchneriella subcapitata and Daphnia magna) and whole-sediment exposure tests (V. fischeri, Chironomus riparius), together with invertebrate community composition (multivariate analyses) to detect short and long-…
Bacteria associated with winter mortalities in laboratory-reared common dentex (Dentex dentex L.)
2007
A pathological study was conducted on laboratory-reared juvenile common dentex (Dentex dentex) suffering trickling and continuous mortalities. During a 3-month period (October-December), water temperature, clinical signs and mortalities were recorded. Moribund or dead fish were examined for bacteria and parasites. Bacteria were isolated from head kidney and external ulcers, and samples from the gills, intestine, stomach, trunk kidney, gall bladder and liver were taken for histology. Cumulative mortality reached 73%, and 80% of fish examined were positive for bacteria (102 isolates). Vibrio splendidus was the most prevalent in head kidney (59.7%) and ulcers (88.9%), and it was frequently iso…
Role of the metalloprotease Vvp and the virulence plasmid pR99 of Vibrio vulnificus serovar E in surface colonization and fish virulence.
2007
The virulence for eels of Vibrio vulnificus biotype 2 serovar E (VSE) is conferred by a plasmid that codifies ability to survive in eel serum and cause septicaemia. To find out whether the plasmid and the selected chromosomal gene vvp plays a role in the initial steps of infection, the VSE strain CECT4999, the cured strain CT218 and the Vvp-deficient mutant CT201 (obtained in this work by allelic exchange) were used in colonization and virulence experiments. The eel avirulent biotype 1 (BT1) strain YJ016, whose genome has been sequenced, was used for comparative purposes. The global results demonstrate that the plasmid does not play a significant role in surface colonization because (i) CEC…
A comparative epizootiologic study of the two fish-pathogenic serovars ofVibrio vulnificusbiotype 2
2010
Vibrio vulnificus biotype 2 is subdivided into two main serovars, serovar E, able to infect fish and humans, and serovar A, only virulent for fish. Serovar E emerged in 1976 as the causative agent of a haemorrhagic septicaemia (warm-water vibriosis) affecting eels cultured in brackish water. Serovar A emerged in 2000 in freshwater-cultured eels vaccinated against serovar E, causing warm-water vibriosis with fish showing a haemorrhagic intestine as the main differential sign. The aim of the present work was to compare the disease caused by both serovars in terms of transmission routes, portals of entry and host range. Results of bath, patch-contact and oral-anal challenges demonstrated that …