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991.
992.
The phytocenotic diversity of the Altai steppe piedmont is described. Plant communities were ordinated along the moisture gradient. The results were used to analyze the structure of vegetation of steppe hill massifs. Distribution of steppe vegetation over an ideal hill was simulated, and the main patterns of distribution were typified.  相似文献   
993.
Lipid synthesis in permeabilized cultured rat hepatocytes   总被引:1,自引:0,他引:1  
Hepatic lipid synthesis was verified and studied in lysolecithin-permeabilized cultured rat hepatocytes and compared to that of intact liver cells. Triacylglycerol synthesis in permeabilized cells incubated in the presence of glycerol 3-phosphate and long chain fatty acids approached that of intact hepatocytes. Similarly, phosphatidylcholine synthesis in permeable cells incubated in the presence of exogenous CDP-choline was similar to that of intact hepatocytes and at the expense of microsomal neutral lipid synthesis. Phosphatidic acid accumulation in lysolecithin-permeabilized liver cells was remarkably increased as compared to that of intact cells, and its synthesis was mostly accounted for by the activity of mitochondrial glycerol-3-phosphate acyltransferase. Mitochondrial-generated phosphatidate was found to migrate to the endoplasmic reticulum, thus establishing a novel lipid esterification pathway which begins in mitochondrial glycerol 3-phosphate acylation and results in microsomal triacylglycerol and phospholipid synthesis. The free access of permeabilized liver cells to substrates and modulators of lipid synthesis, while maintaining an overall synthetic pattern similar to that of intact hepatocytes, makes them a system of choice for studying hepatic lipid synthesis in general and the microsomal/mitochondrial distribution of fluxes in particular.  相似文献   
994.
N.C. Lee 《CMAJ》1990,142(11):1176-1177
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995.
Yellow lupine seeds were found to contain two proteins and a low molecular weight fraction possessing the ability to bind Mo, W and radionuclides from the Chernobyl nuclear power in vivo and the 185W isotope in vitro. These proteins differ in their electrophoretic mobility. The electrophoretically less mobile protein undergoes proteolytic degradation; the proteolytic product retains the ability to accumulate microelements.  相似文献   
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Spontaneous aggregation of glycosylated, desialated, oxidized and malondialdehyde modified low density lipoprotein (LDL) as well as LDL of coronary heart disease patients has been discovered using methods for determination of light transmission fluctuations in suspensions and gel filtration. At the same time; LDL of healthy donors failed to aggregate under conditions of cellular culture. On the other hand, human aortic cells from unaffected intima incubated with modified LDL, but not native LDL of healthy donors, showed a rise in esterified cholesterol levels. There was a strong correlation between the degree of LDL aggregation and intracellular cholesterol ester accumulation (r-0.86, p 0.001, n-21). Removal of aggregates by passing preparations through and 0.1 um filter significantly inhibited the accumulation of cholesterol esters. The obtained data point to the essential, if not decisive, role of LDL aggregation in the processes of lipid accumulation by intimal cells in vitro.  相似文献   
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