Studies on the inhibition of methanogenesis and dechlorination by (4-hydroxyphenyl) chloromethanesulfonate

The purpose of this study was to demonstrate the inhibitory effect of chemicals on methane emissions in paddy soil. We found that (4-hydroxyphenyl) chloromethanesulfonate (C-1) has a methanogenic inhibition activity, and we studied its inhibition mechanism using laboratory tests. The study found that C-1 treatment of flooded soil did not significantly affect the bacterial community but rather the archaeal community; particularly, Methanosarcina spp. C-1 strongly inhibited the aceticlastic methanogenesis route. It was suggested that the inhibitory target of C-1 was different from the well-known methanogenic inhibitor 2-bromoethanesulfonate, which targets methyl-coenzyme M reductase of methanogen. In addition, C-1 had a secondary effect of inhibiting the dechlorination of chlorophenols. Although field trials are required as the next development step, C-1 can be used to reduce methane emissions from paddy fields, one of the largest sources in the agricultural sector.     

Characterization of gelatinolytic enzymes in the skeletal muscle of red sea bream Pagrus major

Gelatinolytic enzymes were partially purified from the skeletal muscle of red sea bream Pagrus major and characterized to obtain information on post mortem tenderization of fish muscle. Four gelatinolytic activities, G1 (90 kDa), G2 (65 kDa), G3 (60 kDa), and G4 (100 kDa), were detected in the Q Sepharose column. G1, the major gelatinolytic enzyme, and G4 were identified as serine proteinases from results of inhibitor spectrum and substrate specificity. By contrast, G2 and G3 were found to be metalloproteinases since these were inhibited by ethylenediamine tetraacetic acid and o-phenanthroline, and activated by 4-aminophenylmercuric acetate. The optimum pH and temperature of these enzymes were in the ranges of 7–9 and 20–40°C, respectively.     

Possession of identical nonconjugative plasmids by different isolates of Pasteurella multocida does not imply clonality

Experiments were performed to test the hypothesis that possession of the same nonconjugative R plasmid by different isolates of Pasteurella multocida implied that they were of the same clone. Seven isolates of P. multocida were studied, two possessed an identical nonconjugative R plasmid (pVM109), four possessed another (pVM110), and one isolate possessed a nonconjugative R plasmid related to pVM110. Phenotypic and genotypic characteristics of the isolates were determined and compared. Isolates possessing the same nonconjugative R plasmid were shown to be different, and isolates possessing a different nonconjugative R plasmid were shown to be the same. We conclude that possession of an identical nonconjugative R plasmid by two isolates of P. multocida does not imply clonality.