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1.
Yuichiro Arai Se KyungKim Hiroyasu Kinemuchi Takeshi Tadano Shinetsu Satoh Nobunori Satoh Katsuyuki Oyama Kensuke Kisara 《Neurochemistry international》1990,17(4):587-592
The present study was carried out mainly to clarify whether the two amphetamine metabolites, p-hydroxyamphetamine (P-OHA) and p-hydroxynorephedrine (p-OHN) are taken up by mouse brain 5-hydroxytryptamine (5-HT) nerve terminals to inhibit type A monoamine oxidase (MAO-A) and then potentiate the abnormal behavior, head-twitch. Of the two metabolites, only intracerebroventricular p-OHA, at 80 μg/mouse, sufficient to cause a head-twitch response (HTR), appreciably inhibited MAO-A activity without affecting MAO-B activity in homogenates of the mouse striatum, hypothalamus and the rest of the forebrain; and p-OHN did not inhibit either type of MAO at the dose tested. Estimation of intra- and extrasynaptosomal MAO-A activity showed that both metabolites significantly inhibited only the intrasynaptosomal deamination of 5-HT by MAO-A with p-OHA being more potent. Taken together with our previous findings, these present results clearly indicate that p-OHA may accumulate in the 5-HT nerve terminals through the uptake system, and concomitantly inhibit MAO-A activity. These actions of p-OHA may increase intraneuronal 5-HT levels and then potentiate 5-HT release to cause interaction with the post-synaptic 5-HT receptors. 相似文献
2.
Resuscitation of Vibrio cholerae O1 strain TSI-4 from a viable but nonculturable state by heat shock 总被引:3,自引:0,他引:3
Sun Nyunt Wai Tetsuhiro Moriya Katsuhiko Kondo Hiroyasu Misumi Kazunobu Amako 《FEMS microbiology letters》1996,136(2):187-191
Abstract Vibrio cholerae strain TSI-4 was incubated in an M9 salt solution at 15 °C for more than 100 days. The plate counts showed no viable cells on day 30, but a broth culture from that day showed the growth of bacteria. However, after 35 days the bacteria entered the nonculturable state, based on the assessment of both the plate counts and broth culture. A portion of the culture was heated at 45 °C for 1 min in a water bath and subsequently plated onto a nutrient agar plate. More than 1000 colonies were recovered after this heat-shock treatment. The recovered cells showed the same chromosomal DNA pattern in the restriction map and the same outer membrane protein pattern in SDS-PAGE. Recovery of viable cells by heat-shock was achieved in cultures grown on M9 salt but not from cultures grown in phosphate-buffered saline. This suggests that the presence of NH4 Cl in the M9 salt solution may support the growth of the bacteria in a low nutrient medium, while also playing an important role in resuscitation. 相似文献
3.
Summary Transgenic cucumber (Cucumis sativus L.) plants were successfully obtained from hypocotyl explants inoculated with Agrobacterium tumefaciens, which harbored a binary vector plasmid with NOS-nptII, CaMV 35S-I-gus and CaMV 35S-hph genes. Acetosyringone enhanced the efficiency of transformation at the cut surface cells of hypocotyl explants during five days of co-cultivation. Transformed cells were more effectively selected using 20–30 mg/l hygromycin B than using 50–100 mg/l kanamycin. Shoot regeneration occurred within 4–6 wks, and 12 of 21 regenerated plantlets displayed strong GUS expression in the very young leaves. All of 8 GUS-positive R0 plants examined showed single or a few positive bands by Southern blot analysis. The expression of the CaMV 35S-I-gus gene was observed in various tissues and organs of R0 and R1 transgenic cucumber plants. 相似文献
4.
Hiroyasu Kitashiba Takayoshi Iwai Kinya Toriyama Masao Watanabe Kokichi Hinata 《Sexual plant reproduction》1996,9(3):186-188
The vegetative-to-floral transition ofBrassica campestris cv. Osome was induced by vernalization. Poly(A)+RNA was isolated from the transition shoot apex after 6 weeks of vernalization, the floral apex after 12 weeks of vernalization and the expanded leaves just before vernalization, and cDNAs were synthesized. These cDNAs were used for subtraction and differential screening to select cDNA preferentially present in the transition and floral apices. Nucleotide sequences of the resulting 14 cDNA clones were determined, and northern blot analysis was carried out on six cDNAs. Two cDNA clones which did not show significant similarity to known genes were shown to be preferentially expressed in the floral apex. 相似文献
5.
A mutation at proline-115 in the A-factor receptor protein of Streptomyces griseus abolishes DNA-binding ability but not ligand-binding ability. 总被引:2,自引:0,他引:2 下载免费PDF全文
A-factor (2-isocapryloyl-3R-hydroxymethyl-gamma-butyrolactone) and its specific receptor protein (ArpA) are required for streptomycin production and aerial mycelium formation in Streptomyces griseus. A mutant strain HO1 that produced streptomycin and formed aerial mycelium and spores was derived from an A-factor-deficient mutant, S. griseus HH1. The phenotypes of mutant HO1 were found to result from a single amino acid replacement of ArpA; the proline residue at position 115 in the wild-type ArpA was replaced by serine, yielding mutant ArpA (P115S). The mutant ArpA (P115S) was still able to form a homodimer and possessed A-factor-binding ability but lost the ability to bind DNA. The properties of P115S suggest that ArpA consists of two independently functional domains, one for A-factor binding and one for DNA binding, and that proline-115 plays an important role in DNA binding. This is in agreement with the idea that A-factor binding to the COOH-terminal domain of ArpA causes a subtle conformational change of the distal NH2-terminal DNA-binding domain, resulting in dissociation of ArpA from DNA. 相似文献
6.
The response characteristics of an electronic neuron model proposed by the authors are investigated. Periodic stimulating pulse sequences with a fixed frequency are applied to the analog neuron model and the response pulse sequences are studied. In the degenerate case, the state transition of the neuron model during one period of the stimulating pulse sequence is described by a first order piecewise linear difference equation with a jump. It is shown that the periodic response pulse sequences of the neuron model belong to a special class of pulse sequences generated by a simple algorithm, and that the relation between the pulse width (or amplitude) of the stimulating pulse and the firing rate of the neuron model takes the form of an extended Cantor function. 相似文献
7.
Preparation of Uridine Diphosphate-N-Acetylgalactosamine from Uridine Diphosphate-N-Acetylglucosamine by Using Microbial Enzymes 下载免费PDF全文
A method was developed for the large scale preparation of uridine diphosphate-N-acetylgalactosamine (UDP-GalNAc) from uridine diphosphate-N-acetylglucosamine (UDP-GlcNAc) by means of microbial enzymes. With Bacillus subtilis cell-free extract as a source of UDP-GlcNAc 4-epimerase, about 35% of the UDP-GlcNAc added was converted to UDP-GalNAc. After the residual UDP-GlcNAc was degraded to uridine triphosphate and N-acetylglucosamine-1-phosphate with a protamine-treated extract of bakers' yeast as a source of UDP-GlcNAc pyrophosphorylase, UDP-GalNAc was separated by anion-exchange column chromatography. The nucleotide was recovered by adsorption on charcoal and elution with ammoniacal ethanol. The final yield was about 100 μmol. 相似文献
8.
Activation of peroxisome proliferator-activated receptor-alpha stimulates both differentiation and fatty acid oxidation in adipocytes 总被引:1,自引:0,他引:1
Goto T Lee JY Teraminami A Kim YI Hirai S Uemura T Inoue H Takahashi N Kawada T 《Journal of lipid research》2011,52(5):873-884
Peroxisome proliferator-activated receptor-α (PPARα) is a dietary lipid sensor, whose activation results in hypolipidemic effects. In this study, we investigated whether PPARα activation affects energy metabolism in white adipose tissue (WAT). Activation of PPARα by its agonist (bezafibrate) markedly reduced adiposity in KK mice fed a high-fat diet. In 3T3-L1 adipocytes, addition of GW7647, a highly specific PPARα agonist, during adipocyte differentiation enhanced glycerol-3-phosphate dehydrogenase activity, insulin-stimulated glucose uptake, and adipogenic gene expression. However, triglyceride accumulation was not increased by PPARα activation. PPARα activation induced expression of target genes involved in FA oxidation and stimulated FA oxidation. In WAT of KK mice treated with bezafibrate, both adipogenic and FA oxidation-related genes were significantly upregulated. These changes in mRNA expression were not observed in PPARα-deficient mice. Bezafibrate treatment enhanced FA oxidation in isolated adipocytes, suppressing adipocyte hypertrophy. Chromatin immunoprecipitation (ChIP) assay revealed that PPARα was recruited to promoter regions of both adipogenic and FA oxidation-related genes in the presence of GW7647 in 3T3-L1 adipocytes. These findings indicate that the activation of PPARα affects energy metabolism in adipocytes, and PPARα activation in WAT may contribute to the clinical effects of fibrate drugs. 相似文献
9.
Kumio Yokoigawa Yoko Okubo Hiroyasu Kawai Nobuyoshi Esaki Kenji Soda 《Journal of Molecular Catalysis .B, Enzymatic》2001,12(1-6):27-35
We describe the structure and function of psychrophilic alanine racemases from Bacillus psychrosaccharolyticus and Pseudomonas fluorescens. These enzymes showed high catalytic activities even at 0°C and were extremely labile at temperatures over 35°C. The enzymes were also found to be less resistant to organic solvents than alanine racemases from thermophilic and mesophilic bacteria, both in vivo and in vitro. Both enzymes have a dimeric structure and contain 2 mol of pyridoxal 5′-phosphate (PLP) per mol as a coenzyme. The enzyme from B. psychrosaccharolyticus was found to have a markedly large Km value (5.0 μM) for PLP in comparison with other reported alanine racemases, and was stable at temperatures up to 50°C in the presence of excess amounts of PLP. The dissociation of PLP from the P. fluorescens enzyme may trigger the unfolding of the secondary structure. The enzyme from B. psychrosaccharolyticus has a distinguishing hydrophilic region around residue no. 150 in its deduced amino acid sequence, whereas the corresponding regions of other Bacillus alanine racemases are hydrophobic. The position of this region in the three dimensional structure of this enzyme was predicted to be in a surface loop surrounding the active site. This hydrophilic region may interact with solvent, reduce the compactness of the active site, and destabilize the enzyme. 相似文献
10.
Vasculogenesis, the in-situ assembly of angioblast or endothelial progenitor cells (EPCs), may persist into adult life, contributing to new blood vessel formation. However, EPCs are scattered throughout newly developed blood vessels and cannot be solely responsible for vascularization. Here, we identify an endothelial progenitor/stem-like population located at the inner surface of preexisting blood vessels using the Hoechst method in which stem cell populations are identified as side populations. This population is dormant in the steady state but possesses colony-forming ability, produces large numbers of endothelial cells (ECs) and when transplanted into ischaemic lesions, restores blood flow completely and reconstitutes de-novo long-term surviving blood vessels. Moreover, although surface markers of this population are very similar to conventional ECs, and they reside in the capillary endothelium sub-population, the gene expression profile is completely different. Our results suggest that this heterogeneity of stem-like ECs will lead to the identification of new targets for vascular regeneration therapy. 相似文献