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51.
The preparation and antigenic property of 3 beta-hydroxy-5-cholen-24-oic acid-bovine serum albumin (BSA) conjugate in which the hapten is linked to the carrier protein through an (O-carboxymethyl) oxime bridge at the C-19 position on the steroid nucleus is described. Antibody raised against antigen in the rabbit possessed high titer and specificity to 3 beta-hydroxy-5-cholen-24-oic acid, exhibiting no significant cross-reactions with various bile acids. 相似文献
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Inhibition of Thiamine Pyrophosphate Utilization by Thiamine or Its Monophosphate in Escherichia coli 下载免费PDF全文
The growth of a thiamine pyrophosphate auxotroph of Escherichi coli was inhibited by either thiamine or thiamine monophosphate, and the growth of a thiamine monophosphate auxotroph was inhibited by thiamine. The thiamine pyrophosphate-dependent oxidation of pyruvate was inhibited by thiamine with whole cells of the thiamine pyrophosphate auxotroph but not with cell extracts prepared from the same organism. In addition, the thiamine pyrophosphate uptake of the thiamine pyrophosphate auxotroph was inhibited by either thiamine or thiamine monophosphate. Although the thiamine pyrophosphate uptake of a revertant, selected for prototrophy from the thiamine monophosphate auxotroph, was inhibited by thiamine to an extent comparable to that observed with the thiamine monophosphate auxotroph, its growth was no longer inhibited by thiamine. A possible mechanism for the inhibition by thiamine and thiamine monophosphate in the utilization of thiamine pyrophosphate is discussed. 相似文献
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Serum levels of 7 alpha-hydroxycholesterol and activities of hepatic microsomal cholesterol 7 alpha-hydroxylase in surgical patients were analyzed by capillary gas-liquid chromatography-selected ion monitoring technique using a new internal standard, 5 alpha-cholestane-3 beta, 7 beta-diol. We found that concentrations of 7 alpha-hydroxycholesterol obtained after alkaline hydrolysis were higher than those without alkaline hydrolysis, indicating that a considerable amount of 7 alpha-hydroxycholesterol in human serum is present in esterified form. Esterified 7 alpha-hydroxycholesterol could also be quantitatively hydrolyzed with cholesterol esterase, suggesting that fatty acid is bound at the 3 beta-position of the cholestenediol. The serum levels of esterified and free 7 alpha-hydroxycholesterol in patients with cholelithiasis were 198.0 +/- 90.3 and 48.3 +/- 19.8 pmol/ml (mean +/- SD), respectively, and were similar to those in patients without hepatobiliary diseases. After treatment with chenodeoxycholic acid (300 mg per day) for 7 to 10 days, esterified and free 7 alpha-hydroxycholesterol levels decreased to 64.9 +/- 33.6 and 20.5 +/- 11.1 pmol/ml, respectively. Activity of cholesterol 7 alpha-hydroxylase was also inhibited. Treatment with ursodeoxycholic acid (600 mg per day) for 7 to 10 days had no inhibitory effect on serum 7 alpha-hydroxycholesterol levels and the enzyme activity. In all groups, high correlations were found between the activity of cholesterol 7 alpha-hydroxylase and serum levels of 7 alpha-hydroxycholesterol: free (r = 0.71, n = 38, P less than 0.001); esterified (r = 0.87, n = 38, P less than 0.001); total (r = 0.87, n = 38, P less than 0.001). Esterified and total 7 alpha-hydroxycholesterol was more highly correlated with the enzyme activity than the free form. We conclude that a significant amount of 3 beta-acyl esters of 7 alpha-hydroxycholesterol is present in human serum and that serum levels of esterified and/or total 7 alpha-hydroxycholesterol are likely to reflect the activity of hepatic cholesterol 7 alpha-hydroxylase and thus the amount of primary bile acids synthesized in the liver. 相似文献
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M H Kim R Nakayama P Manos J E Tomlinson E Choi J D Ng D Holten 《Journal of lipid research》1989,30(5):663-671
Rats were fasted or fasted and refed simple purified diets so the effects of individual carbohydrates or fats could be studied. Freshly isolated hepatocytes from these animals were used to measure both apoE synthesis and mRNA levels so any changes in apoE synthesis that might occur without changes in its mRNA could be detected. Some of these experiments were done with both sexes. Both fasting and fasting and refeeding a 60% glucose fat-free diet significantly increased spoE synthesis. However, cyclic AMP is not likely to rapidly mediate the effect of fasting since dibutyryl cAMP slightly lowered (rather than increased) apoE synthesis and mRNA when injected into rats for 4.5 h. Dietary fat had no effect either in the absence of carbohydrate or when consumption of carbohydrate was constant in pair-fed rats. ApoE mRNA levels remained normal for 4 days in primary hepatocytes cultured in medium that had only amino acids as an energy source. Added hormones or fructose had no significant effect. Thus, only fasting and fasting and refeeding glucose were able to significantly change apoE synthesis or mRNA levels. Synthesis of apoE may be regulated to increase when apoE is secreted with very low density lipoprotein or when apoE in secreted high density lipoprotein is needed to acquire cholesteryl esters for the synthesis of bile salts and acids by liver. 相似文献
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Differentiation of germ cells in seminiferous tubules transplanted to testes of germ cell-deficient mice of W/Wv and Sl/Sld genotypes 总被引:1,自引:0,他引:1
H Kuroda H Nakayama M Namiki K Matsumoto Y Nishimune Y Kitamura 《Journal of cellular physiology》1989,139(2):329-334
(WB X C57BL/6)F1-W/Wv (hereafter, WBB6F1-W/Wv) mice and (WC X C57BL/6)F1-Sl/Sld (hereafter, WCB6F1-Sl/Sld) mice are sterile due to the deficient spermatogenesis in the testes. The cause of deficient spermatogenesis in WBB6F1-W/Wv mice is considered to be a defect in germ cells themselves, whereas that in WCB6F1-Sl/Sld mice is considered to be a defect in tissue environment necessary for differentiation of germ cells. Seminiferous tubules isolated from cryptorchid testes of C57BL/6- +/+ mice were transplanted into the testes of WBB6F1-W/Wv and WCB6F1-Sl/Sld mice to clarify that the extratubular environment of these mice was intact or not. Type A spermatogonia in the transplanted tubules normally differentiated into spermatids, suggesting that the extratubular environment is intact in both WBB6F1-W/Wv and WCB6F1-Sl/Sld mice. 相似文献
59.
Nakayama Ishizue; Miyazawa Takeshige; Kobayashi Masatomo; Kamiya Yuji; Abe Hiroshi; Sakurai Akira 《Plant & cell physiology》1990,31(2):195-200
The effects of a novel plant growth regulator (PGR) prohexadionecalcium (BX-112; calcium 3,5-dioxo-4-propionylcyclohexanecarboxylate)on shoot elongation caused by exogenously applied GA1, GA3,GA4) GA19 and GA20 were investigated in rice (Oryza sativa L.cv. Nihonbare and cv. Tan-ginbozu) seedling test. Dependingon the dose, BX-112 reduced shoot elongation in both cultivarscaused by GA19 and GA20, but not by GA1. When a high dose ofBX-112 (e.g. 250 ng/plant and over) was applied with GA1, orGA4, shoot elongation was even promoted. This promotive effect,however, was not observed with GA3. These results suggest thatBX-112 inhibits gibberellin (GA) biosynthesis in the rice plantat the 3ß- and 2ß-hydroxylation of GAs,namely steps of activation and inactivation, respectively. (Received September 6, 1989; Accepted November 27, 1989) 相似文献
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