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1.
Y Shinoda A Shouji T Yamane A Suzuki T Ashida H Kihara M Ohno 《Journal of biochemistry》1990,107(1):84-86
Crystallization and a preliminary crystallographic study of Trimeresurus flavoviridis (habu snake) phospholipase A2 (PLA2) were carried out. Although crystals were obtained from various solutions, crystals suitable for X-ray analysis could be obtained from polyethylene glycol solutions only when a repeated seeding technique was applied starting from twinned crystals. The crystal is monoclinic with space group P21, with a = 44.1, b = 55.7, c = 48.8 A, and beta = 92.4 degrees. An asymmetric unit contains a dimer consisting of two identical subunits made of 122 amino acids. The crystal reflects X-rays beyond 2.5 A. A Pt derivative gave a good isomorphous crystal. 相似文献
2.
Mannitol-1-phosphate dehydrogenase (MtlD) is required for mannitol and glucitol assimilation in Bacillus subtilis: possible cooperation of mtl and gut operons 下载免费PDF全文
Watanabe S Hamano M Kakeshita H Bunai K Tojo S Yamaguchi H Fujita Y Wong SL Yamane K 《Journal of bacteriology》2003,185(16):4816-4824
3.
Okada Y Makino S Tobe T Okada N Yamazaki S 《Applied and environmental microbiology》2002,68(4):1541-1547
Transposon insertional mutants of Listeria monocytogenes were constructed to identify genes involved in osmotolerance, and one mutant that showed reduced growth under high osmotic pressure was obtained. The cloned gene from the transposon insertion site of the mutant, named rel, was 2,214 bp in length and had very high homology to relA of Bacillus subtilis, which encodes guanosine tetraphosphate (ppGpp) and guanosine pentaphosphate (pppGpp) [collectively designated (p)ppGpp] synthetase during stringent response. The mutant showed a deficiency in (p)ppGpp accumulation. In the parental strain, the amount of intracellular (p)ppGpp was not increased after an osmotic upshift but was slightly decreased compared with the level before the upward shift. The reduced osmotolerance of the mutant was restored to a level almost equal to that of the parent strain when the chromosomal region that included rel of L. monocytogenes was introduced into the mutant. After exposure to methyl glucoside, the rel mutant accumulated (p)ppGpp at a higher level than the basal level and partially restored the ability to grow in NaCl-supplemented brain heart infusion broth. The mutant was found to grow in chemically defined minimal medium supplemented with glycine betaine or carnitine, so-called compatible solutes, and 4% NaCl. Our results suggest that the appropriate intracellular concentration of (p)ppGpp is essential for full osmotolerance in L. monocytogenes and that its mechanism is different from that for the accumulation of compatible solutes. 相似文献
4.
Tomoo Kamiya A-Hon Kown Toshiki Kanemaki Yoichi Matsui Shouji Uetsuji Tadayoshi Okumura Yasuo Kamiyama 《In vitro cellular & developmental biology. Animal》1998,34(2):131-137
Summary The Anaeropack system for cell culture, which was originally designed for the growth of anaerobic bacteria, was used to produce
a hypoxic atmosphere for cultured hepatocytes. We measured changes in the oxygen and carbon dioxide concentrations and the
atmospheric temperature in an airtight jar. We also measured changes in the pH of the medium during hypoxia to assess the
accuracy of this system. Moreover, we used three durations (2, 3, and 4 h) of hypoxia and 8 h of reoxygenation in cultured
rat hepatocytes, and then measured the lactate dehydrogenase (LDH), ketone body concentration (acetoacetate + β-hydroxybutyrate),
and the ketone body ratio (KBR: acetoacetate/β-hydroxybutyrate) in the medium in order to assess the suitability of this system
as a model for reperfusion following liver ischemia. The oxygen concentration dropped to 1% or less within 1 h. The concentration
of carbon dioxide rose to about 5% at 30 min after the induction of the hypoxic conditions, and was maintained at this level
for 5 h. No effect of the reaction heat produced by the oxygen absorbent in the jar was recognized. The extent of cell injury
produced by changing the hypoxic parameters was satisfactorily reflected by the KBR, the ketone body concentration, and the
LDH activity released into the medium. Because this model can duplicate the conditions of the hepatocytes during revascularization
following ischemic liver, and the Anaeropack system for cell culture is easy to manipulate, it seems suitable for the experimental
study of hypoxic injury and revascularization in vitro. 相似文献
5.
Shibata K Sugaya N Ono W Abe K Takahashi S Kera Y 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》2011,879(29):3229-3234
We describe a method for the detection and quantification of D-aspartate N-methyltransferase activity. The enzyme catalyzes the S-adenosyl-L-methionine-dependent N-methylation of D-aspartate to form N-methyl-D-aspartate (NMDA). NMDA is detected directly by high-performance liquid chromatography (HPLC) of their (+)- and/or (-)-1-(9-fluorenyl)ethyl chloroformate fluorescent derivatives. The NMDA production in the assay mixture is linearly proportional to the incubation time and the amount of tissue homogenate. Using a 10 min incubation time, the method allows detection of the enzyme activity below 10 fmol/min. It can be used to analyze kinetic behavior and to quantify the enzyme from a wide variety of organisms. 相似文献
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8.
Matsushima S Kinugawa S Ide T Matsusaka H Inoue N Ohta Y Yokota T Sunagawa K Tsutsui H 《American journal of physiology. Heart and circulatory physiology》2006,291(5):H2237-H2245
Oxidative stress plays an important role in the structural and functional abnormalities of diabetic heart. Glutathione peroxidase (GSHPx) is a critical antioxidant enzyme that removes H(2)O(2) in both the cytosol and mitochondia. We hypothesized that the overexpression of GSHPx gene could attenuate left ventricular (LV) remodeling in diabetes mellitus (DM). We induced DM by injection of streptozotocin (160 mg/kg ip) in male GSHPx transgenic mice (TG+DM) and nontransgenic wildtype littermates (WT+DM). GSHPx activity was higher in the hearts of TG mice compared with WT mice, with no significant changes in other antioxidant enzymes. LV thiobarbituric acid-reactive substances measured in TG+DM at 8 wk were significantly lower than those in WT+DM (58 +/- 3 vs. 71 +/- 5 nmol/g, P < 0.05). Heart rate and aortic blood pressure were comparable between groups. Systolic function was preserved normal in WT+DM and TG+DM mice. In contrast, diastolic function was impaired in WT+DM and was improved in TG+DM as assessed by the deceleration time of peak velocity of transmitral diastolic flow and the time needed for relaxation of 50% maximal LV pressure to baseline value (tau; 13.5 +/- 1.2 vs. 8.9 +/- 0.7 ms, P < 0.01). The TG+DM values were comparable with those of WT+Control (tau; 7.8 +/- 0.2 ms). Improvement of LV diastolic function was accompanied by the attenuation of myocyte hypertrophy, interstitial fibrosis, and apoptosis. Overexpression of GSHPx gene ameliorated LV remodeling and diastolic dysfunction in DM. Therapies designed to interfere with oxidative stress might be beneficial to prevent cardiac abnormalities in DM. 相似文献
9.
Cloning of rel from Listeria monocytogenes as an Osmotolerance Involvement Gene 总被引:2,自引:0,他引:2 下载免费PDF全文
Yumiko Okada Sou-ichi Makino Toru Tobe Nobuhiko Okada Shouji Yamazaki 《Applied microbiology》2002,68(4):1541-1547
Transposon insertional mutants of Listeria monocytogenes were constructed to identify genes involved in osmotolerance, and one mutant that showed reduced growth under high osmotic pressure was obtained. The cloned gene from the transposon insertion site of the mutant, named rel, was 2,214 bp in length and had very high homology to relA of Bacillus subtilis, which encodes guanosine tetraphosphate (ppGpp) and guanosine pentaphosphate (pppGpp) [collectively designated (p)ppGpp] synthetase during stringent response. The mutant showed a deficiency in (p)ppGpp accumulation. In the parental strain, the amount of intracellular (p)ppGpp was not increased after an osmotic upshift but was slightly decreased compared with the level before the upward shift. The reduced osmotolerance of the mutant was restored to a level almost equal to that of the parent strain when the chromosomal region that included rel of L. monocytogenes was introduced into the mutant. After exposure to methyl glucoside, the rel mutant accumulated (p)ppGpp at a higher level than the basal level and partially restored the ability to grow in NaCl-supplemented brain heart infusion broth. The mutant was found to grow in chemically defined minimal medium supplemented with glycine betaine or carnitine, so-called compatible solutes, and 4% NaCl. Our results suggest that the appropriate intracellular concentration of (p)ppGpp is essential for full osmotolerance in L. monocytogenes and that its mechanism is different from that for the accumulation of compatible solutes. 相似文献
10.
Kimihiko Shibata Atsuko Tarui Natsumi Todoroki Shinjiro Kawamoto Shouji Takahashi Yoshio Kera Ryo-hei Yamada 《Comparative biochemistry and physiology. Part B, Biochemistry & molecular biology》2001,130(4)
The presence of N-methyl-
-aspartate (NMLA) was demonstrated in bivalves, Corbicula sandai and Tapes japonica. To our knowledge, this is the first report on the occurrence of NMLA in animal tissues. NMLA in bivalve tissues was identified according to the following findings; (a) its derivatives with (+)- and (−)- 1-(9-fluorenyl)ethyl chloroformate (FLEC) behaved identically with those of authentic NMLA, respectively, on high-performance liquid chromatography (HPLC), (b) its derivatives with (+)- and (−)- FLEC behaved identically with (−)- and (+)-FLEC derivatives of authentic N-methyl-
-aspartate (NMDA), respectively, on HPLC and (c) its behavior on thin-layer chromatography was the same as those of authentic NMLA. We also describe the distribution of NMDA, and
- and
-aspartate, to which N-methylaspartate enantiomers are structurally related. NMDA was more widely dirtributed than NMLA in bivalves. These bivalves containing NMLA showed lower
-aspartate contents and
/(
+
) ratios of aspartate, than the bivalves containing NMDA. 相似文献