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81.
Stereospecific hydroxylation of 3-deoxy-1,2:5,6-di-O-isopropylidene-3-C-trans-and 3-C-cis-(methoxycarbonylmethylene)-α-D-ribo-hexofuranose (2 and 3, respectively), with potassium permanganate in pyridine afforded 3-C-[S- and R-hydroxy-(methoxycarbonyl)methyl]-1,2:5,6-di-O-isopropylidene-α-D-glucofuranose, (6 and 7, respectively), in a combined yield, after chromatography, of 43%. Selective formation of monomethanesulfonates (9a and 10a) and p-toluenesulfonates (9b and 10b), followed by treatment with sodium azide and reduction of the azide, afforded the methyl 2-D-(and 2-L-)(3-deoxy-1,2:5,6-di-O-isopropylidene-α-D-glucofuranos-3-yl)-glycinates (12a and 13a, respectively). Basic hydrolysis of the latter compounds yielded 2-D- and 2-L-(3-deoxy-1,2:5,6-di-O-isopropylidene-α-D-glucofuranos-3-yl)glycine (12b and 13b, respectively). The structures of the glycosyl amino acids were correlated with that of L-alanine by circular dichroism. 相似文献
82.
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84.
Koichi Iijima 《Cell and tissue research》1970,103(4):460-474
Summary Detailed histochemical studies have been conducted on the morphology of the Golgi apparatus by applying the thiamine pyrophosphatase technique (Novikoff and Goldfisher, 1961) to the neurons of supraoptic and paraventricular nuclei of normal and dehydrated rabbits. The neurons in both nuclei were classified into five categories on the basis of the morphology of the Golgi apparatus. The number of cells in individual categories were counted to evaluate the percentage of each category in the whole nucleus.Neurons have many vesicles which show the tendency to form clusters. Such clusters are present also in the basal bodies. The Golgi apparatus is localized near one side of the nucleus in many neurons. The neurons indicate phasic activity of resting, anabolic and catabolic stages under normal conditions.During dehydration, the Golgi apparatus went through the three stages of network formation, the increase of the budding-off process and later on disintegration. The supraoptic nucleus reacted to the TPPase test more severely than the paraventricular nucleus, whereas the former went through the stages more slowly than the latter. The paraventricular nucleus also revealed sensitivity to osmotic stress. 相似文献
85.
Summary The effect of competition pressure on the sequential pattern of adult emergence was studied by using the experimental population
of the azuki bean weevil. The density and pattern of emergence curves of the parental adult induced the changes in the shape
of emergence curve of the progeny as well as the number of progeny individuals. In order to explain these changes, a simple
mathematical model which has two independent variables, the population density and the capacity of environment, was introduced.
The model generated basically similar patterns of emergene curves as observed in the present experiments. This means that
the model displayed well the competition pressure which differentially acted upon early-born and late-born individuals in
the populations being at different densities and which were differentially received by individual progeny according to the
sequential distributions of parents. This different severity of competition pressure resulted in the difference of time when
the pressure compelled influences on the sequential distribution of adult emergence. Therefore, early developed individuals
may have good chance to survive, but the competition pressure works as a factor modifying their fundamental superiority, especially
in the scramble type of competition.
Intense crowding of the azuki bean weevil gave rise to the scramble type of competition in the relation between the numbers
of adults emerged in two successive generations. When parental emergence concentrated in a short term and at high density,
the competition becomes intense, resulting in the inferiority of early developed individuals, in the decrease in number at
the next generation and in the increase of duration for emergence. 相似文献
86.
Participation of P-450 in 7 alpha-hydroxylation of cholesterol 总被引:1,自引:0,他引:1
87.
Physiological role of malic enzymes in the liver 总被引:2,自引:0,他引:2
88.
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90.
Koichi Fujii 《Population Ecology》1965,7(2):118-125
- A theoretical model for the competition curve, which stands on a few simple assumptions, was proposed.
- Some applications were done to actual data, and during these applications the validity of the present model and its assumptions was discussed.
- From the present model it can be expected that there is a discrete competition mechanism even in the appearently continuous medium.