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991.
Mice were fed a diet containing 1.5% cholesterol, and the total cholesterol balance and the distribution of the consumed sterol among excreta, liver, and carcass were determined, using experimental periods of 9–14 days. It was observed that an average of approximately 12% of the cholesterol was either destroyed or chemically modified. When, however, 1% sulfasuxidine and 0.04% streptomycin were added to the diet, all the sterol “put in” was recovered, within the limits of error of the method. These results were tentatively interpreted to indicate that under the conditions of these experiments, microorganisms of the intestine were primarily responsible for the destruction or modification of the consumed sterol, as observed in the absence of antibacterial drugs. 相似文献
992.
V jarovisovaných a nejarovisovaných obilkách jedné ozimé a jedné jarní odr?dy p?enice byly chromatograficky stanoveny látky typu auxin? a giberelin?. Chromatogramy byly vyhodnoceny pomocí biologických test?. U ozimé odr?dy jsme nena?li rozdíly v rozlo?ení r?stových látek mezi jarovisovanou a nejarovisovanou variantou. U jarní odr?dy jsme rozdíly na?li. Na základě výsledk? soudíme, ?e rozdíly mezi oběma variantami jarní odr?dy byly zp?sobeny nespecifickým p?sobením nízké teploty a ?e proces jarovisace není kausálně spjat se změnami hladiny r?stových látek. 相似文献
993.
994.
995.
996.
VICTOR G. BRUCE 《The Journal of eukaryotic microbiology》1970,17(2):328-334
SYNOPSIS. Chlamydomonas reinhardi has a biological clock regulating phototaxis in dividing and non-dividing cultures; it also can exert some control on growth of continuous cultures. The period length is ∼ 24 hr; it is temperature-compensated and not dependent on the average growth rate. The rhythm can be entrained or phased by light-dark conditions. In dividing cultures a periodic fluctuation in cell number and total protein persists in continuous light. 相似文献
997.
Richard A. Popham 《Biotechnic & histochemistry》1948,23(2):49-54
Selected current ideas on the mordanting of plant tissues are presented in the hope that they will be of practical assistance, especially to the beginner. The nature of the mordanting process and the results which may be expected following mordanting are briefly described. Specific technics are presented for the mordanting of natural dyes, synthetic dyes generally, the basic synthetic dyes and the acid synthetic dyes. 相似文献
998.
999.
Summary The iliofibularis muscle ofXenopus laevis is reported to contain five types of fibres which have different force—velocity relationships. Ten fibres of each type were selected on the basis of succinate dehydrogenase activity, cross-sectional area and location in the muscle, in order to assess the validity of the fibre type classification.Maximum calcium-stimulated myofibrillar ATPase activity (V
max) and apparent Michaelis constant (K
m) for ATP were determined for these 50 fibres from serial sections. The values obtained varied according to the type of fibre. Type 1 had the highest and type 5 the lowest values forK
m andV
max.In a separate experiment, single freeze-dried fibres were used to determine the relationship between their ATP content and apparentK
m for ATP. There was a tendency for high ATP concentrations in fibres with highK
m values.When myofibrillar ATPase activity was related to the maximum velocity of shortening of the five fibre types, a significant correlation was found. It is concluded that calcium-stimulated myofibrillar ATPase histochemistry allows an estimate of the maximum shortening velocity of muscle fibres fromXenopus laevis. 相似文献
1000.