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排序方式: 共有241条查询结果,搜索用时 15 毫秒
231.
Maeda I Delessert S Hasegawa S Seto Y Zuber S Poirier Y 《The Journal of biological chemistry》2006,281(17):11729-11735
The role of the Saccharomyces cerevisae peroxisomal acyl-coenzyme A (acyl-CoA) thioesterase (Pte1p) in fatty acid beta-oxidation was studied by analyzing the in vitro kinetic activity of the purified protein as well as by measuring the carbon flux through the beta-oxidation cycle in vivo using the synthesis of peroxisomal polyhydroxyalkanoate (PHA) from the polymerization of the 3-hydroxyacyl-CoAs as a marker. The amount of PHA synthesized from the degradation of 10-cis-heptadecenoic, tridecanoic, undecanoic, or nonanoic acids was equivalent or slightly reduced in the pte1Delta strain compared with wild type. In contrast, a strong reduction in PHA synthesized from heptanoic acid and 8-methyl-nonanoic acid was observed for the pte1Delta strain compared with wild type. The poor catabolism of 8-methyl-nonanoic acid via beta-oxidation in pte1Delta negatively impacted the degradation of 10-cis-heptadecenoic acid and reduced the ability of the cells to efficiently grow in medium containing such fatty acids. An increase in the proportion of the short chain 3-hydroxyacid monomers was observed in PHA synthesized in pte1Delta cells grown on a variety of fatty acids, indicating a reduction in the metabolism of short chain acyl-CoAs in these cells. A purified histidine-tagged Pte1p showed high activity toward short and medium chain length acyl-CoAs, including butyryl-CoA, decanoyl-CoA and 8-methyl-nonanoyl-CoA. The kinetic parameters measured for the purified Pte1p fit well with the implication of this enzyme in the efficient metabolism of short straight and branched chain fatty acyl-CoAs by the beta-oxidation cycle. 相似文献
232.
233.
The effect of urethan on artificial induction of cleavage in eggs of the sea urchin, Hemicentrotus pulcherrimus, was studied. When the eggs were exposed for 20 minutes to seawater containing urethan (final concentration, 0.08 M) after butyric acid-activation and then treated with hypertonic seawater, the cleavage rate was enchanced by about 1.5 times as compared with the nontreated eggs. In the eggs exposed to urethan–seawater for over 70 minutes many clear spots appeared throughout the cytoplasm. Simultaneously, the pigment granules, which had been embedded within the cortex, migrated to the inner cytoplasm and encircled a monastral centrosphere and clear spots. The clear spots were composed of microtubules much like cytasters, and in the central region of them centrioles were not yet found. The eggs in which the pigment granules disappeared from the cortex may be more susceptible to cleavage induction by succeeding hypertonic treatment. 相似文献
234.
Tomoko Tanaka Kazuo Koike Katsuyoshi Mitsunaga Keiko Narita Seiko Takano Akiko Kamioka Emi Sase Yishan Ouyang Taichi Ohmoto 《Phytochemistry》1995,40(6):1787-1790
Five new chromones, perforatins C-G, together with 10 known compounds were isolated from the wood of Harrisonia perforata. 相似文献
235.
236.
Seiko Yamaguchi Yoshiko Miyazaki Shiro Oka Ikuya Yano 《FEMS immunology and medical microbiology》1996,13(2):107-111
Abstract Recently, extensive attention has been paid to the physiological function of glycosphingolipids (GSLs) of mammalian cell membranes. Among a variety of GSLs, sulfatide (galactosylceramide-3-sulfate) has been proposed to be a specific receptor or binding molecule to microorganisms. However, no report has appeared on the direct stimulation by sulfatide for cellular function differentiation in phagocytic cells. We found that sulfatide showed a marked stimulation for phagocytic processes of human peripheral polymorphonuclear leukocytes (PMN) using heat-killed cells of Staphylococcus aureus coated with isolated lipid. Among mammalian acidic GSLs, sulfatide showed the highest stimulative activity for adhesion, phagocytosis and phagosome—lysosome (P-L) fusion by PMN. On the other hand, neutral GSLs did not stimulate essentially. Relative phagocytic rate of sulfatide-coated staphylococci was six times higher than that of the non-coated control and P-L fusion rate was ten times at maximum, respectively. Although the promotion mechanism of sulfatide for such phagocytosis or P-L fusion is not clear, it was strongly suggested that the existence of negative charges on carbohydrate moiety may be essential for the induction of differentiation of phagocytic cell function via signal transduction systems. 相似文献
237.
Nathalie Durut Mohamed Abou-Ellail Frédéric Pontvianne Sadhan Das Hisae Kojima Seiko Ukai Anne de Bures Pascale Comella Sabine Nidelet Stéphanie Rialle Remy Merret Manuel Echeverria Philippe Bouvet Kenzo Nakamura Julio Sáez-Vásquez 《The Plant cell》2014,26(3):1330-1344
In plants as well as in animals, hundreds to thousands of 45S rRNA gene copies
localize in Nucleolus Organizer Regions (NORs), and the activation or repression of
specific sets of rDNA depends on epigenetic mechanisms. Previously, we reported that
the Arabidopsis thaliana nucleolin protein NUC1, an abundant and
evolutionarily conserved nucleolar protein in eukaryotic organisms, is required for
maintaining DNA methylation levels and for controlling the expression of specific
rDNA variants in Arabidopsis. Interestingly, in contrast with animal
or yeast cells, plants contain a second nucleolin gene. Here, we report that
Arabidopsis NUC1 and NUC2 nucleolin genes are
both required for plant growth and survival and that NUC2 disruption
represses flowering. However, these genes seem to be functionally antagonistic. In
contrast with NUC1, disruption of NUC2 induces CG
hypermethylation of rDNA and NOR association with the nucleolus. Moreover, NUC2 loss
of function triggers major changes in rDNA spatial organization, expression, and
transgenerational stability. Our analyses indicate that silencing of specific rRNA
genes is mostly determined by the active or repressed state of the NORs and that
nucleolin proteins play a key role in the developmental control of this process. 相似文献
238.
Yoshiaki Kawamura Junko Tomida Yuji Morita Takashi Naka Seiko Mizuno & Nagatoshi Fujiwara 《FEMS microbiology letters》2009,298(1):118-123
' Lysobacter enzymogenes ssp. cookii ' was proposed by Christensen and Cook in 1978; however, this subspecies name has not been cited in the Approved Lists of Bacterial Names and therefore the nomenclature has not been validated. In our genetic approach to clarify the relationships of the designated type strain of ' L. enzymogenes ssp. cookii ' PAGU 1119 (GenBank accession number ATCC29488 ) within the genus Lysobacter revealed that the strain was closely related to Lysobacter capsici YC5194 T (99.4%) rather than L. enzymogenes DSM2043 T (97.2%). The value for whole genome DNA–DNA relatedness between strain PAGU 1119 and L. enzymogenes DSM 2043T or L. capsici YC5194 T was 20.7–26.1% or 60.9–62.0%, respectively. Although PAGU 1119 and L. capsici YC5194 T showed relatively high DNA relationships, the fatty acid profiles and some phenotypic characteristics were different, and we concluded that PAGU 1119 should be placed in a new species. We therefore propose a new species with the name Lysobacter cookii sp. nov. The type strain is PAGU 1119T ( ATCC29488 ). 相似文献
239.
Hiroyuki Kawahara Ryo Tamura Seiko Ajioka Yoshikazu Shizuri 《Marine biotechnology (New York, N.Y.)》1999,1(1):98-101
A convenient assay method for estimation of barnacle, Balanus amphitrite, settlement inductive activity was developed. To avoid the inductive effect by comrades and laborious observation requirements,
cyprid larvae were put individually into wells of a 96-well plate. The settlement ratio from the experiment without any inducers
was quite low; therefore this assay allowed easy estimation of settlement inductive activities. Some known inductive agents,
such as serotonin and barnacle extracts, clearly showed inductive activities. This assay method is proven to be suitable for
estimation of barnacle settlement-inducing activities of both water-soluble and -insoluble compounds.
Received October 31, 1997; accepted July 10, 1998. 相似文献
240.