Lefua tokaiensis,a new species of nemacheilid loach from central Japan (Teleostei: Nemacheilidae)

Ichthyological Research - A new nemacheilid loach, Lefua tokaiensis sp. nov., is described from the small mountain streams in the Tokai region, central Honshu, Japan. Lefua tokaiensis is...     

Osteoactivin fragments produced by ectodomain shedding induce MMP-3 expression via ERK pathway in mouse NIH-3T3 fibroblasts

Intact osteoactivin, a novel type I membrane glycoprotein, were shed at a dibasic motif in the juxtamembrane region in C2C12 myoblasts. Extracellular fragments were secreted into the culture media by a putative metalloprotease. Extracellular fragments of osteoactivin, but not control protein, induced matrix metalloprotease-3 (MMP-3) expression in NIH-3T3 fibroblasts. Epidermal growth factor (ERK) kinase inhibitors inhibited the osteoactivin-mediated MMP-3 expression, whereas the extracellular fragment of osteoactivin activated ERK1/2 and p38 in the mitogen-activated protein kinase pathway. Our results suggest that the extracellular fragments of osteoactivin produced by shedding act as a growth factor to induce MMP-3 expression via the ERK pathway in fibroblasts.     

Anaerobic degradation of benzene in BTX mixtures dependent on sulfate reduction

Abstract Enrichment cultures from marine sediments mineralized benzene while using sulfate as the terminal electron acceptor. Parallel cultures using river marsh sediment displayed no activity. Mineralization was confirmed by release of ¹⁴CO₂ from radiolabeled benzene. The dependence on sulfate reduction was demonstrated by stoichiometric balances and the use of specific inhibitors. This work supports recent observations that anaerobic benzene degradation takes place coupled to sulfate reduction.     

Gene-centromere mapping of medaka sex chromosomes using triploid hybrids between Oryzias latipes and O. luzonensis

Four sex-linked genetic markers (SL1, SL2, B2.38 and stsOPQ05-1) on the sex chromosomes of the medaka, O. latipes, were mapped in relation to the centromere by means of triploid hybrids between O. latipes and O. luzonensis. Female F₁ hybrid O. latipes of two inbred strains, Hd-rR and HNI, were crossed with male O. luzonensis. Triploidization was induced by heat-shock treatment. Hatching rate of heat-shock treated eggs was 59%, and that of untreated hybrid eggs was 2%, indicating that most of the hatched fry were triploid. Using these triploid hatched fry, the map distances between the four loci and the centromere were examined. The order was SL2 – centromere – SL1 – B2.38 – stsOPQ05-1 and the map distances were: SL2 – centromere, 1%; centromere – SL1, 18%; SL1 – B2.38, 19%; B2.38 – stsOPQ05-1, 9%. Previous studies using FISH showed that SL2 is located on the short arm of large submetacentric chromosomes, and SL1 was closely linked to SDF (sex-determining factor). The results of gene-centromere mapping of this study show that SL1, B2.38 and stsOPQ05-1 are located on the long arm, and that, SDF is thus also on the long arm of the sex chromosomes.     

Leukotriene B4: metabolism and signal transduction

Leukotriene B4 (LTB4) is known as one of the most potent chemoattractants and activators of leukocytes and is involved in inflammatory diseases. Enzymes involved in the biosynthesis and metabolism of LTB4 have been cloned, and their properties are well understood. Two G-protein-coupled receptors (BLT1 and BLT2) have been cloned and characterized. BLT1 and BLT2 are high- and low-affinity LTB4 receptors, respectively, and form a gene cluster in human and mouse. In this article recent findings on the metabolism of and the receptors for LTB4 are reviewed. We also discuss briefly a coreceptor role of BLT in HIV infection, and ion channel modification by LTB4.     

Accumulation of anthranilic acid and N-glucosylanthranilic acid by a Corynebacterium glutamicum mutant resistant to DL-serine hydroxamate

During a study on the effect of DL-serine hydroxamate on Corynebacterium glutamicum (JCM1318, a wild strain), a mutant resistant to the drug, strain TO3002, was isolated. This mutant accumulated five Ehrlich's reagent positive fluorescent substances in the culture medium. Two major and one minor fluorescent products were isolated by preparative high-performance liquid chromatography following charcoal column chromatography from the culture supernatant. One major product was identified as anthranilic acid whose molecular ion was confirmed to be 137 by a measurement of liquid chromatography-mass spectrometry (LC-MS), and NMR spectrum coincided with that of anthranilic acid. LC-MS spectra of another major and the minor product showed that they had the same molecular weight of 299. This major product was supported to be N-glucosylanthranilic acid (N-o-carboxyphenyl-1-beta-glucosylamine) by two-dimensional (1)H and (13)C NMR analyses. The minor product was speculated to be an Amadori compound derived from N-glucosylanthranilic acid. N-Glucosylanthranilic acid accumulated in the early phase, then decreased in the late phase of the culture. In contrast, the accumulation of anthranilic acid increased remarkably in the late phase of the fermentation. Based on this phenomenon, it was assumed that N-glucosylanthranilic acid once accumulated was decomposed to form anthranilic acid, at least in large part, with the progress of fermentation. The strain TO3002 showed a leaky requirement for L-tryptophan or indole (but did not for anthranilic acid) and resistance to DL-serine hydroxamate.