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排序方式: 共有428条查询结果,搜索用时 31 毫秒
1.
Participation of microsomal aldehyde reductase in long-chain fatty alcohol synthesis in the rat brain 总被引:1,自引:0,他引:1
The participation of microsomal aldehyde reductase in long-chain fatty alcohol synthesis in the rat brain was examined. A reaction mixture of [1-14C]hexadecanoic acid with brain microsomes and NADPH formed two radioactive products having the same mobilities as pure hexadecanal (RF 0.61) and hexadecanol (RF 0.22), respectively, on TLC plates. The product of the RF 0.61 spot was further identified as hexadecanal using gas-liquid chromatography after methylation and TLC of its reduced product with LiAlH4 and semicarbazide. The ratio of hexadecanal to hexadecanol varied from 0.4 to 1.2 under the present experimental conditions. When solubilized rat brain microsomes were applied to a Sepharose 4B column coupled with the rabbit antibody raised against rat liver microsomal NADPH-cytochrome-c reductase, which reacts with aldehyde reductase from rat brain, the eluted fraction ceased to form [14C]hexadecanol but continued to form [14C]hexadecanal from [14C]hexadecanoic acid. These results strongly indicate that hexadecanal is the intermediate in the synthesis of hexadecanol from hexadecanoic acid in rat brain microsomes with the participation of microsomal aldehyde reductase. 相似文献
2.
3.
N Yuasa T Taniguchi M Goda M Shibatani T Imada H Hihara 《National Institute of Animal Health quarterly》1983,23(3):75-77
An attempt was made to isolate chicken anemia agent (CAA) from chickens suffering from anemia in the field by using MDCC - MSB1 , which was an established cell line derived from Marek's disease lymphoma. When 99 chickens of 15 flocks were examined, CAA was isolated from 58 chickens of 12 flocks. The rate of CAA isolation with MDCC - MSB1 cells was almost the same as that determined by an in vivo method by chick inoculation. It was shown that CAA was more closely concerned with anemic diseases of chickens in the field than fowl adenoviruses. 相似文献
4.
Takeo Yoshimura Takuro Kobayashi Shuichiro Goda Ikuo Goto 《Neurochemical research》1994,19(6):735-741
The repetitive passages of a Schwann cell culture results in the appearance of immortalized cells. In order to investigate the direct effects of cyclic AMP (cAMP) on Schwann cell proliferation, we used the immortalized Schwann cells because the responses of a short-term Schwann cell culture to agents increasing the intracellular cAMP are more complicated and it does not seem that all of them are due to the direct effects of cAMP. By adding up to 200 M of forskolin, an adenylate cyclase activator, to the culture medium, Schwann cell proliferation was inhibited and the intracellular 1,2-diacylglycerol (DG) level was decreased in a dose-dependent manner to 44 and 53% of the control values, respectively. The protein phosphorylation activity in the cytosol from the cell treated with 100 M forskolin, assayed with myelin basic protein as the acceptor, decreased to 78% and this inhibition was then reversed by the addition of 1-oleoyl-2-acetyl-sn-glycerol (OAG), a membrane-permeable DG, to the assay mixture. The cell proliferation inhibited by forskolin was also restored by the addition of OAG. These data suggest that cAMP inhibits both the activity of protein kinase C (PKC) and consequently cell proliferation through suppression of intracellular DG level, an activator of PKC. Since the inositol 1,4,5-triphosphate level and the hydrolysis of phosphatidylcholine to DG and phosphorylcholine were not affected, forskolin therefore appears to suppress the de novo synthesis of DG. 相似文献
5.
Nielsen J; Peixoto AA; Piccin A; Costa R; Kyriacou CP; Chalmers D 《Molecular biology and evolution》1994,11(6):839-853
The region of the clock gene period (per) that encodes a repetitive tract
of threonine-glycine (Thr-Gly) pairs has been compared between Dipteran
species both within and outside the Drosophilidae. All the non-
Drosophilidae sequences in this region are short and present a remarkably
stable picture compared to the Drosophilidae, in which the region is much
larger and extremely variable, both in size and composition. The
accelerated evolution in the repetitive region of the Drosophilidae appears
to be mainly due to an expansion of two ancestral repeats, one encoding a
Thr-Gly dipeptide and the other a pentapeptide rich in serine, glycine, and
asparagine or threonine. In some drosophilids the expansion involves a
duplication of the pentapeptide sequence, but in Drosophila pseudoobscura
both the dipeptide and the pentapeptide repeats are present in larger
numbers. In the nondrosophilids, however, the pentapeptide sequence is
represented by one copy and the dipeptide by two copies. These observations
fulfill some of the predictions of recent theoretical models that have
simulated the evolution of repetitive sequences.
相似文献
6.
Rab9 functions in transport between late endosomes and the trans Golgi network. 总被引:33,自引:5,他引:28 下载免费PDF全文
Rab proteins represent a large family of ras-like GTPases that regulate distinct vesicular transport events at the level of membrane targeting and/or fusion. We report here the primary sequence, subcellular localization and functional activity of a new member of the rab protein family, rab9. The majority of rab9 appears to be located on the surface of late endosomes. Rab9, purified from Escherichia coli strains expressing this protein, could be prenylated in vitro in the presence of cytosolic proteins and geranylgeranyl diphosphate. In vitro-prenylated rab9 protein, but not C-terminally truncated rab9, stimulated the transport of mannose 6-phosphate receptors from late endosomes to the trans Golgi network in a cell-free system that reconstitutes this transport step. Rab7, a related rab protein that is also localized to late endosomes, was inactive in the in vitro transport assay, despite its efficient prenylation and capacity to bind and hydrolyze GTP. These results strongly suggest that rab9 functions in the transport of mannose 6-phosphate receptors between late endosomes and the trans Golgi network. Moreover, our results confirm the observation that a given organelle may bear multiple rab proteins with different biological functions. 相似文献
7.
Tomomi Hidaka Masao Goda Tomohisa Kuzuyama Naomi Takei Makoto Hidaka Haruo Seto 《Molecular & general genetics : MGG》1995,249(3):274-280
The biosynthetic pathway for production of the antibiotic fosfomycin by Streptomyces wedmorensis consists of four steps including the formation of a C-P bond and an epoxide. Fosfomycin production genes were cloned from genomic DNA using S. wedmorensis mutants blocked at different steps of the biosynthetic pathway. Four genes corresponding to each of the biosynthetic steps were found to be clustered in a DNA fragment of about 5 kb. Nucleotide sequencing of a large fragment revealed the presence of ten open reading frames, including the four biosynthetic genes and six genes with unknown functions. 相似文献
8.
Evolutionary origin of human and primate malarias: evidence from the circumsporozoite protein gene 总被引:8,自引:1,他引:7
We have analyzed the conserved regions of the gene coding for the
circumsporozoite protein (CSP) in 12 species of Plasmodium, the malaria
parasite. The closest evolutionary relative of P. falciparum, the agent of
malignant human malaria, is P. reichenowi, a chimpanzee parasite. This is
consistent with the hypothesis that P. falciparum is an ancient human
parasite, associated with humans since the divergence of the hominids from
their closest hominoid relatives. Three other human Plasmodium species are
each genetically indistinguishable from species parasitic to nonhuman
primates; that is, for the DNA sequences included in our analysis, the
differences between species are not greater than the differences between
strains of the human species. The human P. malariae is indistinguishable
from P. brasilianum, and P. vivax is indistinguishable from P. simium; P.
brasilianum and P. simium are parasitic to New World monkeys. The human P.
vivax-like is indistinguishable from P. simiovale, a parasite of Old World
macaques. We conjecture that P. malariae, P. vivax, and P. vivax-like are
evolutionarily recent human parasites, the first two at least acquired only
within the last several thousand years, and perhaps within the last few
hundred years, after the expansion of human populations in South America
following the European colonizations. We estimate the rate of evolution of
the conserved regions of the CSP gene as 2.46 x 10(-9) per site per year.
The divergence between the P. falciparum and P. reichenowi lineages is
accordingly dated 8.9 Myr ago. The divergence between the three lineages
leading to the human parasites is very ancient, about 100 Myr old between
P. malariae and P. vivax (and P. vivax-like) and about 165 Myr old between
P. falciparum and the other two.
相似文献
9.
Dietary-induced increase in lactase activity and in immunoreactive lactase in adult rat jejunum. 总被引:4,自引:2,他引:2 下载免费PDF全文
Adult rats that had been fed on a low-starch high-fat diet for 7 days were force-fed with either the same diet or isoenergetic diets containing 40% of energy as either sucrose or lactose. Within 12h, the increase in jejunal lactase activity in sucrose- and lactose-fed rats was accompanied by a corresponding increase in immunoreactive lactase protein. 相似文献
10.
Photosynthetic enhancement studies performed at 619 nm (excitation of Systems I and II) and at 446 nm (mainly excitation of System I) revealed an 18% photosynthetic enhancement simultaneously with a 31% reduction in glycolate excretion. This observation supports the hypothesis that some glycolate may be consumed in an oxidation process associated with System I when System II is poorly excited and the supply of electrons from the water splitting process of photosynthesis is low. 相似文献