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21.
The duality of teleost gonadotropins 总被引:5,自引:0,他引:5
Hiroshi Kawauchi Kunimasa Suzuki Hiromichi Itoh Penny Swanson Nobuko Naito Yoshitaka Nagahama Masumi Nozaki Yasumitu Nakai Seiga Itoh 《Fish physiology and biochemistry》1989,7(1-6):29-38
The duality of salmon gonadotropins has been proved by biochemical, biological, and immunological characterization of two
chemically distinc gonadotropins. GTH I and GTH II were equipotent in stimulating estradiol production, whereas GTH II appears
to be more potent in stimulating maturational steroid synthesis. The ratio of plasma levels and pituitary contents of GTHs
and the secretory control by a GnRH suggest that GTH I is the predominant GTH during vitellogenesis and early stages of spermatogenesis
in salmonids, whereas GTH II is predominant at the time of spermiation and ovulation. GTH I and GTH II are found in distinctly
separate cells. In trout, GTH I is expressed first in ontogeny, whereas GTH II cells appear coincident with the onset of spermatogenesis
and vitellogenesis, and increase dramatically at the time of final reproductive maturation. Comparison of the amino acid sequences
of polypeptides and the base sequences of cDNA revealed that salmon GTH I β is more similar to bovine FSHβ than bovine LHβ
and salmon GTH II β shows higher homology to bovine LHβ than to bovine FSHβ. The existence of two pituitary gonadotropins
in teleosts as well as tetrapods suggests that the divergence of the GTH gene took place earlier than the time of divergence
of teleosts from the main line of evolution leading to tetrapods. 相似文献
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Weller GR Kysela B Roy R Tonkin LM Scanlan E Della M Devine SK Day JP Wilkinson A d'Adda di Fagagna F Devine KM Bowater RP Jeggo PA Jackson SP Doherty AJ 《Science (New York, N.Y.)》2002,297(5587):1686-1689
In eukaryotic cells, double-strand breaks (DSBs) in DNA are generally repaired by the pathway of homologous recombination or by DNA nonhomologous end joining (NHEJ). Both pathways have been highly conserved throughout eukaryotic evolution, but no equivalent NHEJ system has been identified in prokaryotes. The NHEJ pathway requires a DNA end-binding component called Ku. We have identified bacterial Ku homologs and show that these proteins retain the biochemical characteristics of the eukaryotic Ku heterodimer. Furthermore, we show that bacterial Ku specifically recruits DNA ligase to DNA ends and stimulates DNA ligation. Loss of these proteins leads to hypersensitivity to ionizing radiation in Bacillus subtilis. These data provide evidence that many bacteria possess a DNA DSB repair apparatus that shares many features with the NHEJ system of eukarya and suggest that this DNA repair pathway arose before the prokaryotic and eukaryotic lineages diverged. 相似文献
28.
Gelfand MJ Raver JL Nishii L Leslie LM Lun J Lim BC Duan L Almaliach A Ang S Arnadottir J Aycan Z Boehnke K Boski P Cabecinhas R Chan D Chhokar J D'Amato A Ferrer M Fischlmayr IC Fischer R Fülöp M Georgas J Kashima ES Kashima Y Kim K Lempereur A Marquez P Othman R Overlaet B Panagiotopoulou P Peltzer K Perez-Florizno LR Ponomarenko L Realo A Schei V Schmitt M Smith PB Soomro N Szabo E Taveesin N Toyama M Van de Vliert E Vohra N Ward C Yamaguchi S 《Science (New York, N.Y.)》2011,332(6033):1100-1104
With data from 33 nations, we illustrate the differences between cultures that are tight (have many strong norms and a low tolerance of deviant behavior) versus loose (have weak social norms and a high tolerance of deviant behavior). Tightness-looseness is part of a complex, loosely integrated multilevel system that comprises distal ecological and historical threats (e.g., high population density, resource scarcity, a history of territorial conflict, and disease and environmental threats), broad versus narrow socialization in societal institutions (e.g., autocracy, media regulations), the strength of everyday recurring situations, and micro-level psychological affordances (e.g., prevention self-guides, high regulatory strength, need for structure). This research advances knowledge that can foster cross-cultural understanding in a world of increasing global interdependence and has implications for modeling cultural change. 相似文献
29.
Sobolev VS Khan SI Tabanca N Wedge DE Manly SP Cutler SJ Coy MR Becnel JJ Neff SA Gloer JB 《Journal of agricultural and food chemistry》2011,59(5):1673-1682
The peanut plant (Arachis hypogaea L.), when infected by a microbial pathogen, is capable of producing stilbene-derived compounds that are considered antifungal phytoalexins. In addition, the potential health benefits of other stilbenoids from peanuts, including resveratrol and pterostilbene, have been acknowledged by several investigators. Despite considerable progress in peanut research, relatively little is known about the biological activity of the stilbenoid phytoalexins. This study investigated the activities of some of these compounds in a broad spectrum of biological assays. Since peanut stilbenoids appear to play roles in plant defense mechanisms, they were evaluated for their effects on economically important plant pathogenic fungi of the genera Colletotrichum, Botrytis, Fusarium, and Phomopsis. We further investigated these peanut phytoalexins, together with some related natural and synthetic stilbenoids (a total of 24 compounds) in a panel of bioassays to determine their anti-inflammatory, cytotoxic, and antioxidant activities in mammalian cells. Several of these compounds were also evaluated as mammalian opioid receptor competitive antagonists. Assays for adult mosquito and larvae toxicity were also performed. The results of these studies reveal that peanut stilbenoids, as well as related natural and synthetic stilbene derivatives, display a diverse range of biological activities. 相似文献
30.
A survey of 2000 farms in south-west Scotland revealed that 3.5% of the cereal area had been treated with pesticides for the control of leatherjackets (Tipula spp.) in 1975. A small area of recently established grass and some turnip fields were also treated. DDT and gamma-HCH were the most commonly used compounds with an estimated use respectively of 1863 and 376 kg of active ingredient. Pesticide usage in 1975 appeared to have been consistent with the generally low leatherjacket population in that year. 相似文献