Two sulfur-containing ansamycin antibiotics fromStreptomyces albolongus

Summary Two sulfur-containing ansamycin antibiotics were isolated from the culture broth ofStreptomyces albolongus C-46366; the major one was identical with awamycin and the minor one was a new ansamycin antibiotic, ansathiazin. Their structures were elucidated from their reactions and spectroscopic analyses. These antibiotics were active against gram-positive bacteria, acid-fast bacteria and a protozoan.We thank Dr I. Umezawa for his generous gift of awamycin. We are grateful to Drs K. Morita, Y. Nakao, H. Okazaki and H. Ono for their interest throughout this work. Thanks are also due to Messrs Y. Kono, K. Koyama, H. Fujiuchi and Y. Nakano, and Mrs K. Jinno for their skillful technical assistance.     

Simultaneous determination of antibody to Epstein-Barr virus in prenatal mothers and new-born infants

Zusammenfassung Antikörpertiter gegen EBV wurden in 40 gepaarten Seren von pränatalen Müttern und Neugeborenen gleichzeitig mit indirekter Immunofluoreszenz bestimmt. In 95% hatten sowohl Mütter als auch Neugeborene den Antikörper. Die Titer der Mütter waren mehrheitlich gleich oder höher jenen der Neugeborenen, woraus geschlossen wird, dass der Antikörper gegen EBV von der Mutter diaplacentar auf den Fetus übertragen werden kann.     

Sequence of a novel simian immunodeficiency virus from a wild-caught African mandrill

Since the isolation of an HIV-2-related virus from captive macaques (SIVMAC), the origin of human immunodeficiency viruses, a much debated subject, has been attributed to monkeys. The sequence of SIVAGM, which is derived from a naturally infected African green monkey, shows equal relatedness to HIV-1 and HIV-2, suggesting that the derivation of these viruses from SIVAGM is unlikely. Recent sequence analysis of SIV from a captive sooty mangabey (SIVMAC), however, shows its close relatedness to HIV-2 and SIVMAC, indicating a possible origin of HIV-2 and SIVMAC from SIVSM (refs 4, 7, 9). We report here the sequence of a novel simian lentivirus, SIVMND, isolated from a wild-caught mandrill in Africa. It is distinct from the three other main groups, HIV-1, HIV-2/SIVMAC/SIVSM and SIVAGM, and therefore represents a fourth main group of primate lentiviruses. Phylogenetic analysis indicates that these four main virus groups might have diverged from a common ancestor at about the same time, long before the spread of AIDS in humans.     

Chondroitin proteoglycans are involved in cell division of Caenorhabditis elegans

Glycosaminoglycans such as heparan sulphate and chondroitin sulphate are extracellular sugar chains involved in intercellular signalling. Disruptions of genes encoding enzymes that mediate glycosaminoglycan biosynthesis have severe consequences in Drosophila and mice. Mutations in the Drosophila gene sugarless, which encodes a UDP-glucose dehydrogenase, impairs developmental signalling through the Wnt family member Wingless, and signalling by the fibroblast growth factor and Hedgehog pathways. Heparan sulphate is involved in these pathways, but little is known about the involvement of chondroitin. Undersulphated and oversulphated chondroitin sulphate chains have been implicated in other biological processes, however, including adhesion of erythrocytes infected with malaria parasite to human placenta and regulation of neural development. To investigate chondroitin functions, we cloned a chondroitin synthase homologue of Caenorhabditis elegans and depleted expression of its product by RNA-mediated interference and deletion mutagenesis. Here we report that blocking chondroitin synthesis results in cytokinesis defects in early embryogenesis. Reversion of cytokinesis is often observed in chondroitin-depleted embryos, and cell division eventually stops, resulting in early embryonic death. Our findings show that chondroitin is required for embryonic cytokinesis and cell division.     

Formation of lipoperoxide in the retina of rabbit exposed to high concentration of oxygen

Summary When rabbit was exposed to high concentration of oxygen, lipoperoxide in the retina was increased at 12 h of the exposure, after which period amplitude of electro-retinogram decreased. The degeneration was observed in the visual cell layer of the retina of the exposed animal. The exposure increased lipoperoxide in isolated retina. These data show the intervention of lipoperoxide in retinal degeneration induced by exposure to high concentration of oxygen.     

Interaction of BW755C,a potent inhibitor of lipoxygenase and cyclo-oxygenase,with mitochondrial cytochrome oxidase

Summary The interaction between BW755C (3-amino-1-[m-(trifluoromethyl)phenyl]-2-pyrazoline), a potent inhibitor of both lipoxygenase and cyclo-oxygenase, and respiratory chain in mitochondria and electron transport particles (ETP) from rat livers was examined. BW755C accelerated the oxygen uptake by mitochondria without the addition of substrate for the respiratory chain. Spectrophotometric study revealed that BW755C was quickly oxidized by cytochrome oxidase in mitochondria to a compound possessing an absorption maximum at 524 nm. p-Phenylenediamine (p-diaminobenzene, PPDA), which, like BW755C, serves as an electron donor to cytoschrome oxidase, was shown to inhibit the generation of active oxygen in macrophages; the inhibition was stronger than that of BW755C. These results strongly suggest that the oxidative conversion of BW755C by mitochondrial cytochrome oxidase is associated with its potentially inhibitory action on the active oxygen-generating system in phagocytes.The authors are indebted to Dr M. Hori, Gifu College of Pharmacy and to Dr Y. Orii, Kyoto University for their kind supplies of BW755C and pure cytochrome oxidase, respectively.