Tokai University Junior College

About: Tokai University Junior College is a based out in . It is known for research contribution in the topics: Vibrio parahaemolyticus & Reperfusion injury. The organization has 33 authors who have published 48 publications receiving 732 citations.

Prevalence of Pandemic Thermostable Direct Hemolysin-Producing Vibrio parahaemolyticus O3:K6 in Seafood and the Coastal Environment in Japan

Abstract: Although thermostable direct hemolysin (TDH)-producing Vibrio parahaemolyticus has caused many infections in Asian countries, the United States, and other countries, it has been difficult to detect the same pathogen in seafoods and other environmental samples. In this study, we detected and enumerated tdh gene-positive V. parahaemolyticus in Japanese seafoods with a tdh-specific PCR method, a chromogenic agar medium, and a most-probable-number method. The tdh gene was detected in 33 of 329 seafood samples (10.0%). The number of tdh-positive V. parahaemolyticus ranged from <3 to 93/10 g. The incidence of tdh-positive V. parahaemolyticus tended to be high in samples contaminated with relatively high levels of total V. parahaemolyticus. TDH-producing strains of V. parahaemolyticus were isolated from 11 of 33 tdh-positive samples (short-necked clam, hen clam, and rock oyster). TDH-producing strains of V. parahaemolyticus were also isolated from the sediments of rivers near the coast in Japan. Representative strains of the seafood and sediment isolates were examined for the O:K serovar and by the PCR method specific to the pandemic clone and arbitrarily primed PCR and pulsed-field gel electrophoresis techniques. The results indicated that most O3:K6 tdh-positive strains belonged to the pandemic O3:K6 clone and suggested that serovariation took place in the Japanese environment.

Improved method for detection of Vibrio parahaemolyticus in seafood.

Abstract: We have developed a new, effective procedure for detecting Vibrio parahaemolyticus in seafoods using enrichment and plating onto a chromogenic agar medium. Samples were cultured in salt Trypticase soy broth, which is a nonselective medium, and then a portion of the culture was cultured with salt polymyxin broth, which is a selective medium for V. parahaemolyticus. This two-step enrichment was more effective than the one-step enrichment in salt polymyxin broth alone. The enrichment cultures were then plated onto a new chromogenic agar containing substrates for beta-galactosidase. The V. parahaemolyticus colonies developed a purple color on this growth medium that distinguished them from other related bacterial strains. V. parahaemolyticus was isolated more frequently from naturally contaminated seafood samples using the chromogenic agar than thiosulfate citrate bile salts sucrose agar medium, which is currently used for the isolation of V. parahaemolyticus. Our findings suggest that this new enrichment and isolation scheme is more sensitive and accurate for identifying V. parahaemolyticus in seafood samples than previously used methods.

Dielectric study on hydration of B-, A-, and Z-DNA.

Abstract: Dielectric relaxation peak due to bound water was found around 100 MHz in poly(dG-dC).poly(dG-dC) and calf thymus DNA in water-ethanol mixtures with NaCl buffer. Relaxation time and strength show a transition for poly(dG-dC).poly(dG-dC) at an ethanol composition Cw = 0.45 (w/w) where the structural transition from B- to Z-DNA takes place. It has been suggested that the transition is caused by removal of the bound water molecules preferentially from the phosphate groups. If the bound water molecules are removed equally from the phosphate groups and the grooves, the structural transition from B to A takes place. By analogy with hydration of tropocollagen, it was found that 19 water molecules per one nucleotide are at least necessary to keep B-DNA. Thirteen molecules are bound to A-DNA and 9 molecules to Z-DNA. Stringlike multimers are proposed as available structures of the bound water.

Organic vapor sensitivity in a porous silicon device

Abstract: An organic vapor sensitive device using anodized porous silicon has been developed The device consists of two pn junctions surrounded by the porous silicon layer as a vapor sensing element The devices show an increase of current for exposure to thousands ppm of organic vapor at room temperature A high sensitivity is observed for ethanol vapor The porous silicon combined with the reverse biased pn junction plays an important role for vapor sensing It is discussed that the adsorption of polar molecules in the vicinity of pn junction induces a ‘soft’ breakdown in the reverse biased pn junction