Mechanisms of plasmid-mediated antibiotic resistances in Vibrio parahaemolyticus

The mechanisms of drug resistance of clinical isolate, Vibrio (V.) parahaemolyticus ST550, resistant to chloramphenicol (CP), aminoglycoside antibiotics (AGs) and beta-lactam antibiotics were investigated. The mechanisms of resistance to CP, AGs and beta-lactam antibiotics were dependent on chloramphenicol acetyltransferase (CAT), aminoglycoside-3"-adenylyltransferase AAD(3") and aminoglycoside-3'-phosphotransferase APH(3') and TEM type penicillinase, respectively.     

Estimates of Denitrification and Nitrification in Coastal and Estuarine Sediments

Denitrification and nitrification in sediments of Tama Estuary and Odawa Bay, Japan, were investigated by the combined use of a continuous-flow sediment-water system and a ¹⁵N tracer technique. At Odawa Bay, the nitrification rate was comparable to the nitrate reduction rate, and 70% of the N₂ evolved originated from nitrogenous oxides (nitrate and nitrite) which were produced by the action of nitrifying bacteria in the sediments. At Tama Estuary, the nitrate reduction rate was 11 to 17 times higher than the nitrification rate, and nitrogenous oxides derived from ammonium accounted for only 6 to 9% of the N₂ evolution by denitrification.     

Caprolactam,a light-promoted growth inhibitor in sunflower seedlings

A neutral growth inhibitor, isolated from methanolic extracts of sunflower seedlings, was characterized by spectral data as caprolactam. Light-grown se     

Value of chemical mixture in multiple supralethal X-irradiation of mice

A chemical mixture containing 25 Amoles of MEA, 7 pmoles of AET, and 2 micromoles of 5-HT was found to be of significant value in protecting mice against repeated exposures of 800 R, 1100 R, or 1400 R given at intervals of 28 days. Dose-reduction factors of 2.17, 2.18, 1.95, 2.14, and 1.58 were obtained for the first five exposures. Following the first exposure there was no chemical mortality. The beneficial value of this mixture, however, was limited by the incidence of chemical toxicity which was more prevalent in mice with higher cumulative doses of radiation.     

Xenobrama microlepis,a new genus and species of bramid fish,from subantarctic waters of the South Pacific

Xenobrama microlepis gen. et sp. nov. is described on the basis of 17 adult and subadult specimens collected by surface gill nets, bottom trawl and midwater trawl from the subantarctic waters of the South Pacific Ocean. This monotypic new genus is distinguished from other bramid genera by the following characters: inner lower edges of mandible touching each other (except near symphysis); gill rakers short, thick, and stout; subpectoral region very narrow; interpelvic space flat and wide; vertebrae 49–51; and scales in longitudinal series more than 83. The new taxon is widely distributed in the high seas of the South Pacific, 38–54°S, 79–176°W, but is rather rare compared toBrama spp. in catches of drift gill nets.     

Nematodes of the family Heligmonellidae (Trichostrongyloidea) collected from rodents of the Ryukyu archipelago and Taiwan

Six species of the family Heligmonellidae (Nematoda: Trichostrongyloidea), including 3 new species, are recorded from rodents of the subfamily Murinae in the Ryukyu Archipelago and Taiwan. Heligmonoides ikeharai n. sp. from Tokudaia osimensis muenninki on Mt. Yonaha, Okinawa Island, is characterized by extremely long spicules and hypertrophied ridges in the prevulval region. Heligmonoides taiwanensis n. sp. from Apodemus draco on Mt. Alishan, Taiwan, is distinguished from other members of the genus in having a markedly asymmetrical bursa and stout bursal rays. Heligmonoides alishanensis n. sp. from Niviventer confucianus on Mt. Alishan differs from the allied forms in lacking hypertrophied ridges at the level of the middle of the spicules and in having longer spicules and a smaller body. Nippostrongylus sp. from N. confucianus on Mt. Alishan resembles Nippostrongylus brasiliensis but is distinguishable in that the externolateral ray is almost the same length as the lateroventral ray in the left lobe, and the fused tips of the spicules are thin and straight. Heligmonoides ryukyensis from Mus caroli and Orientostrongylus tenorai from Bandicota indica are first recorded from Taiwan. Heligmonellid nematodes parasitic in wild rodents in these areas are considered to have been introduced with their hosts from the mainlands of China and Japan through land connections in the Pleistocene.