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991.
Summary Pentoses in aqueous acidic solutions were analysed by conversion to furfurals in a gas chromatograph containing a porous polymer packed column at 200°C. Hexoses, volatile fatty acids and fermentation media did not interfere with the measurement of pentoses. 相似文献
992.
Intracellular free Ca2+ concentrations [Ca2+]i were measured in ovine anterior pituitary cells using the quin 2 technique. Thyrotropin-releasing hormone (TRH) increased, dopamine decreased and growth hormone-releasing hormone (GHRH) had no detectable effect on [Ca2+]i. Loading the cells with quin 2, at an intracellular concentration less than that used during calcium determination, reduced both basal growth hormone (GH) and (to a small extent) prolactin secretion. Loading cells with quin 2 also markedly reduced GHRH-stimulated GH secretion. However, TRH-stimulated prolactin secretion was 3-times basal irrespective of quin 2 loading. The results indicate that the use of quin 2 to measure [Ca2+]i in some cell types may be complicated by actions of quin 2 on cellular function. 相似文献
993.
994.
995.
The nucleotide sequence data reported in this paper have been submitted to the GenBank nucleotide sequence database and have
been assigned the accession numbers M25913 and M25914. 相似文献
996.
The effect of pentamidine on ribosomes of the parasitic flagellate Crithidia (Strigomonas) oncopelti 总被引:2,自引:0,他引:2
O C Wallis 《The Journal of protozoology》1966,13(2):234-239
997.
Phillip A. Morin Janette Wallis James J. Moore Ranajit Chakraborty David S. Woodruff 《Primates; journal of primatology》1993,34(3):347-356
Genetic studies of free-ranging primates have been seriously impeded by difficulties of sampling tissues, including the undesirability
of bleeding habituated animals, of transporting frozen samples to the laboratory, and of the inherent inadequacies of accessible
variation including allozymes, mtDNA RFLP patterns and DNA fingerprints. We have developed methods of non-invasive DNA sampling
and DNA-level genotyping which, when combined with a hierarchical analysis of mtDNA sequences and hypervariable nDNA simple
sequence repeat (microsatellite) loci size length polymorphisms, facilitate the resolution of most questions at the individual,
social group (community), population, and species (phylogenetic) levels. This approach, based on DNA amplified from shed hair,
represents an important new tool for the acquisition of genetic information and will facilitate the study and management of
both captive and free-ranging chimpanzees (Pan troglodytes). Our hierarchical analysis of population genetics of chimpanzees has revealed high historical levels of gene flow and large
effective population sizes, as well as substantial divergence between the West African subspecies and chimpanzees from central
and East Africa. At the community level, closer relatedness among philopatric males than among females supports the view that
kin selection has been an evolutionary force shaping male-male cooperation in this species. Results from our study of the
now relatively isolated Gombe community suggest that habitat fragmentation affects population genetic structure and possibly
population viability. 相似文献
998.
999.
J E Bleasdale P Wallis P C MacDonald J M Johnston 《Biochimica et biophysica acta》1979,575(1):135-147
CDPdiacylglycerol:inositol transferase activity in rabbit lung tissue has been characterized and the optimum conditions for assaying this enzyme in vitro were determined. Rabbit lung tissue CDPdiacylglycerol:inositol transferase activity was found primarily in the microsomal fraction. The pH optimum of the enzyme activity was between 8.8 and 9.4, and the reaction was dependent on either Mn2+ or Mg2+. Detergents and Ca2+ inhibited the activity of the enzyme. The apparent Km values of the enzyme for CDPdioleoylglycerol and myoinositol were 0.18 mM and 0.10 mM, respectively. The reversibility of the reaction catalyzed by CDPdiacylglycerol:inositol transferase in microsomes prepared from rabbit lung tissue was demonstrated by the synthesis of [3H]CMPdiacylglycerol when [3H]CMP and phosphatidylinositol were present in the incubation mixture. The reverse reaction was characterized and its importance in the regulation of the acidic phospholipid composition of surfactant during lung development is discussed. The pH optimum for the reverse reaction was 6.2, and the reverse reaction was also dependent on Mn2+ or Mg2+. The apparent Km value of CDPdiacylglycerol:inositol transferase for CMP was found to be 2.8 mM. 相似文献
1000.
Tetradecanoyl phorbol acetate (TPA) stimulates growth hormone (GH) and prolactin secretion from ovine anterior pituitary cells. Pretreatment of the cells with TPA abolishes this effect, presumably due to down-regulation of protein kinase C. Such pretreatment did not alter effects of thyrotropin-releasing hormone or dopamine on prolactin secretion, suggesting no involvement of protein kinase C. Pretreatment with TPA attenuated actions of GH-releasing hormone on GH release (but not actions on cyclic AMP levels), possibly due to depletion of cellular stores of GH. Such pretreatment also attenuated inhibition of GH release by somatostatin, possibly due to phosphorylation of receptors or associated proteins by protein kinase C. 相似文献