scholarly journals Construction and Characterization of an Isogenic Mutant of Vibrio parahaemolyticus Having a Deletion in the Thermostable Direct Hemolysin-Related Hemolysin Gene (trh)

1994 ◽  
Vol 176 (21) ◽  
pp. 6781-6781
Author(s):  
Ming Xu ◽  
Koichiro Yamamoto ◽  
Takeshi Honda
Keyword(s):  
Vibrio Parahaemolyticus ◽  
Isogenic Mutant ◽  
Hemolysin Gene ◽  
Thermostable Direct Hemolysin

scholarly journals Characterization of a Vibrio alginolyticus Strain, Isolated from Alaskan Oysters, Carrying a Hemolysin Gene Similar to the Thermostable Direct Hemolysin-Related Hemolysin Gene (trh) of Vibrio parahaemolyticus

2006 ◽  
Vol 72 (12) ◽  
pp. 7925-7929 ◽  
Author(s):  
Narjol González-Escalona ◽  
George M. Blackstone ◽  
Angelo DePaola
Keyword(s):  
Stationary Phase ◽  
Vibrio Parahaemolyticus ◽  
Vibrio Alginolyticus ◽  
Early Stationary Phase ◽  
Biochemical Characteristics ◽  
First Report ◽  
Hemolysin Gene ◽  
Thermostable Direct Hemolysin

ABSTRACT A Vibrio strain isolated from Alaskan oysters and classified by its biochemical characteristics as Vibrio alginolyticus possessed a thermostable direct hemolysin-related hemolysin (trh) gene previously reported only in Vibrio parahaemolyticus. This trh-like gene was cloned and sequenced and was 98% identical to the trh2 gene of V. parahaemolyticus. This gene seems to be functional since it was transcriptionally active in early-stationary-phase growing cells. To our knowledge, this is the first report of V. alginolyticus possessing a trh gene.

Increased Sensitivity in PCR Detection of tdh-Positive Vibrio parahaemolyticus in Seafood with Purified Template DNA

2003 ◽  
Vol 66 (9) ◽  
pp. 1675-1680 ◽  
Author(s):  
Y. HARA-KUDO ◽  
Y. KASUGA ◽  
A. KIUCHI ◽  
T. HORISAKA ◽  
T. KAWASUMI ◽  
...  
Keyword(s):  
Glass Fiber ◽  
Vibrio Parahaemolyticus ◽  
Detection Sensitivity ◽  
Sea Bream ◽  
Silica Membrane ◽  
Membrane Method ◽  
Hemolysin Gene ◽  
Thermostable Direct Hemolysin ◽  
Increased Sensitivity ◽  
Template Dna

PCR is an important method for the detection of thermostable direct hemolysin gene (tdh)–positive (pathogenichemolysin-producing) strains of Vibrio parahaemolyticus in seafood because tdh-negative (nonpathogenic) V. parahaemolyticus strains often contaminate seafood and interfere with the direct isolation of tdh-positive V. parahaemolyticus. In this study, the use of PCR to detect the tdh gene of V. parahaemolyticus in various seafoods artificially contaminated with tdh-positive V. parahaemolyticus was examined. PCR was inhibited by substances in oysters, squid, mackerel, and yellowtail but not by cod, sea bream, scallop, short-necked clam, and shrimp. To improve detection, DNA was purified by either the silica membrane method, the glass fiber method, or the magnetic separation method, and the purified DNA was used as the PCR primer template. For all samples, the use of the silica membrane method and the glass fiber method increased detection sensitivity. The results of this study demonstrate that the use of properly purified template DNA for PCR markedly increases the effectiveness of the method in detecting pathogenic tdh-positive V. parahaemolyticus in contaminated seafood.

scholarly journals Genetic Characterization of DNA Region Containing the trh and ure Genes of Vibrio parahaemolyticus

2000 ◽  
Vol 68 (10) ◽  
pp. 5742-5748 ◽  
Author(s):  
Kwon-Sam Park ◽  
Tetsuya Iida ◽  
Yoshiharu Yamaichi ◽  
Tomohito Oyagi ◽  
Koichiro Yamamoto ◽  
...  
Keyword(s):  
Vibrio Parahaemolyticus ◽  
Open Reading Frames ◽  
The Other ◽  
Close Proximity ◽  
Mutant Strains ◽  
Thermostable Direct Hemolysin ◽  
Urease Production ◽  
Reading Frames ◽  
Type Nickel

ABSTRACT We have demonstrated that possession of the gene for thermostable direct hemolysin-related hemolysin (trh) coincides with the presence of the urease gene among clinical Vibrio parahaemolyticus strains and that the location of the two genes are in close proximity on the chromosome. Here, we cloned and sequenced the 15,754-bp DNA region containing the trh gene and the gene cluster for urease production from the chromosome of clinicalV. parahaemolyticus (TH3996). We found 16 open reading frames (ORFs) and a lower G+C content (41%) compared with the total genome of this bacterium (46 to 47%). The ure cluster consisted of eight genes, namely, ureDABCEFG andureR. ureR was located 5.2 kb upstream of the other seven genes in the opposite direction. The genetic organization and sequences of the ure genes resembled those found in Proteus mirabilis. Between ureR and the other uregenes, there were five ORFs, which are homologous with the nickel transport operon (nik) of Escherichia coli. We disrupted each of the ureR, ureC, andnikD genes in TH3996 by homologous recombination and analyzed the phenotype of the mutants. In the presence of urea these mutant strains had dramatically less urease activity than the strain they were derived from. Disruption of ureR,nikD, or ureC, however, had no effect on TRH production. The DNA region containing the trh,nik, and ure genes was found in onlytrh-positive strains and not in Kanagawa phenomenon-positive and environmental V. parahaemolyticusstrains. At the end of the region, an insertion sequence-like element existed. These results suggest that the DNA region was introduced intoV. parahaemolyticus in the past through a mechanism mediated by insertion sequences. This is the first reported case that the genes for an ATP-binding cassette-type nickel transport system, which may play a role in nickel transport through bacterial cytoplasmic membrane, are located adjacent to the ure cluster on the genome of an organism.

scholarly journals Hfq regulates the expression of the thermostable direct hemolysin gene in Vibrio parahaemolyticus

2008 ◽  
Vol 8 (1) ◽  
pp. 155 ◽  
Author(s):  
Masayuki Nakano ◽  
Akira Takahashi ◽  
Zehong Su ◽  
Nagakatsu Harada ◽  
Kazuaki Mawatari ◽  
...  
Keyword(s):  
Vibrio Parahaemolyticus ◽  
Hemolysin Gene ◽  
Thermostable Direct Hemolysin

Effects of Dry Storage and Resubmersion of Oysters on Total Vibrio vulnificus and Total and Pathogenic (tdh+/trh+) Vibrio parahaemolyticus Levels

2015 ◽  
Vol 78 (8) ◽  
pp. 1574-1580 ◽  
Author(s):  
THOMAS P. KINSEY ◽  
KERI A. LYDON ◽  
JOHN C. BOWERS ◽  
JESSICA L. JONES
Keyword(s):  
Vibrio Parahaemolyticus ◽  
Storage Time ◽  
Vibrio Vulnificus ◽  
Ambient Air ◽  
Most Probable Number ◽  
Probable Number ◽  
Ambient Temperatures ◽  
Dry Storage ◽  
Hemolysin Gene ◽  
Thermostable Direct Hemolysin

Vibrio vulnificus (Vv) and Vibrio parahaemolyticus (Vp) are the two leading causes of bacterial illnesses associated with raw shellfish consumption. Levels of these pathogens in oysters can increase during routine antifouling aquaculture practices involving dry storage in ambient air conditions. After storage, common practice is to resubmerge these stored oysters to reduce elevated Vv and Vp levels, but evidence proving the effectiveness of this practice is lacking. This study examined the changes in Vv and in total and pathogenic (thermostable direct hemolysin gene and the tdh-related hemolysin gene, tdh+ and trh+) Vp levels in oysters after 5 or 24 h of dry storage (28 to 32°C), followed by resubmersion (27 to 32°C) for 14 days. For each trial, replicate oyster samples were collected at initial harvest, after dry storage, after 7 days, and after 14 days of resubmersion. Oysters not subjected to dry storage were collected and analyzed to determine natural undisturbed vibrio levels (background control). Vibrio levels were measured using a most-probable-number enrichment followed by real-time PCR. After storage, vibrio levels (excluding tdh+ and trh+ Vp during 5-h storage) increased significantly (P < 0.001) from initial levels. After 7 days of resubmersion, Vv and total Vp levels (excluding total Vp in oysters stored for 5 h) were not significantly different (P > 0.1) from levels in background oysters. Vv and total and pathogenic Vp levels were not significantly different (P > 0.1) from levels in background oysters after 14 days of resubmersion, regardless of dry storage time. These data demonstrate that oyster resubmersion after dry storage at elevated ambient temperatures allows vibrio levels to return to those of background control samples. These results can be used to help minimize the risk of Vv and Vp illnesses and to inform the oyster industry on the effectiveness of routine storing and resubmerging of aquaculture oysters.

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