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991.
Katharina S. Buser Bernhard Kopp Peter Gehr Ewald R. Weibel Dr. Hans Hoppeler 《Cell and tissue research》1982,225(2):427-436
Summary Growing rats (4 weeks old) were kept for 3 weeks at 11° C and 24° C respectively. The cold-adapted animals showed a significantly higher oxygen consumption (64%). Volume density of subsarcolemmal and interfibrillar mitochondria as well as volume density of fat droplets were estimated in M. soleus and the diaphragm of both groups. In cold-adapted animals, the total volume of mitochondria was significantly increased by 24% in diaphragm and 37% in M. soleus. The volume of subsarcolemmal mitochondria was almost doubled in each muscle, but the volume of interfibrillar mitochondria did not change significantly. The surface of the inner mitochondrial membranes per unit volume of mitochondrion in M. soleus was significantly increased both in interfibrillar and subsarcolemmal mitochondria, whereas the surface of the outer mitochondrial membranes per unit volume of mitochondrion was increased only in the subsarcolemmal mitochondria. The volume of fat droplets in the diaphragm and M. soleus of cold adapted animals increased significantly by 62% and 150% respectively. 相似文献
992.
T. P. Afanasieva S. Yu. Filippovich V. Yu. Sokolovsky M. S. Kritsky 《Archives of microbiology》1982,133(4):307-311
The specific activity of NAD+ kinase (ATP:NAD+ 2-phosphotransferase, EC 2.7.1.23) from Neurospora crassa shows sharp peaks when the organism enters a new developmental stage of the asexual life cycle: the peaks are observed during hydration and germination of conidia, at the transition from exponential to stationary growth and at the photostimulated conidiation. As stimulation of NAD+ kinase activity by light in conidiating mycelium is not sensitive to translation inhibitors, the activiation of pre-existing molecules, rather than induction of protein synthesis de novo may be supposed. Enzyme electrophoresis revealed the presence of four forms of NAD+ kinase having different apparent molecular weights (I=333,000; II=306,000; III=229,000 and IV=203,000). Manifestation of the activity of individual forms of NAD+ kinase is developmentally controlled: form III is most abundant during vegetative growth, forms I and II prevail in conidia. At the conidial germination the increase of NAD+ kinase activity is associated with the activation of form III, whereas during photostimulation of conidiation form II is the most activated one. Therefore, certain molecular forms of the enzyme may be regarded as biochemical markers for different developmental stages of N. crassa. 相似文献
993.
994.
The ubiquinone protein, QP-C, in reduced ubiquinone-cytochrome c reductase (the b?c1-III complex) shows a stable ubisemiquinone radical when the enzyme is reduced by succinate in the presence of catalytic amounts of succinate dehydrogenase and QP-S. At room temperature using EPR technique the redox titration of the b?c1-III complex in the presence of redox dyes or succinate/fumarate couple reveals that the ubisemiquinone radical has a midpoint potential of approximately +67 mV at pH 8.0. Further analysis yields E1 of +83 mV and E2 of +51 mV corresponding to () and () or other electronated forms, respectively. The equilibrium radical concentration has been found to be affected both by pH and succinate/fumarate couple. At pH 9.0 the radical shows the maximal amplitude and stability. Below pH 7.0, little radical was detected. The electron spin relaxation behavior of ubisemiquinone radical, as examined by microwave power saturation, indicates that the ubisemiquinone radical of QP-C is somewhat isolated from other paramagnetic centers. The effects of phospholipids, QP-S, and other agents on ubisemiquinone radical formation as well as the enzymatic activity of QP-C have been studied in detail. 相似文献
995.
996.
Factors affecting population density, group size and territory size of the European badger, Meles meles 总被引:4,自引:0,他引:4
This paper discusses the relationship between the distribution and biomass of the main prey of European badgers, Meles meles and the badgers group size, territory size and population density. The distribution of areas rich in earthworms, Lumbricus spp., is correlated with badger range size, whilst badger group size increases with the biomass of worms per badger territory and badger density increases with overall worm biomass. Regulation of badger density in an area is likely to take place through regulation of group size, in the absence of other factors such as persecution and lack of suitable sett-sites. 相似文献
997.
998.
Hans Bisgaard Johannes Kristensen Jrgen Sndergaard 《Prostaglandins & other lipid mediators》1982,23(6):797-801
Using a laser-Doppler-flowmeter the microvascular response to LTC4 and LTD4 was measured. Intradermal injection of 1 Ug LTC4 and LTD4 caused an increase in the microvascular cutaneous bloodflow. The increase in flow was equal to that caused by histamine in equimolar amounts. Blocking the triple-response did not change the response. The values measured after injection of histamine and leucotrienes were about 10–15 times the values found in undisturbed skin and represents probably a maximally dilated vascular bed. Injection of the leucotrienes caused a slight sensation of pain. 相似文献
999.
David End Nathaniel Tolson Mei-Ying Yu Gordon Guroff 《Journal of cellular physiology》1982,111(2):140-148
The phorbol ester tumor promoter 12-0-tetradecanoylphorbol-13-acetate (TPA) specifically inhibited the binding of radioiodinated epidermal growth factor (125I-EGF) to rat pheochromocytoma (PC12) cells in a noncompetitive fashion with an apparent Ki of 11–26 nM. Both TPA and EGF elicited similar biological responses in PC12 cells including enhanced incorporation of 3H-choline and 32P-orthophosphate into macromolecules, induction of ornithine decarboxylase, and stimulation of the phosphorylation of a 30,000 MW nonhistone, chromosome-associated protein. These effects were also elicited by nerve growth factor (NGF) which, in contrast to the former agents, is a differentiating stimulus for the PC12 cells. The effects of TPA were additive or more than additive to the effects of NGF and EGF. When PC12 cells were induced to differentiate by treatment with NGF for 72 hours, the binding of 125I-EGF and responses to EGF were reduced by approximately 70%. The response of PC12 cells to the tumor promoter TPA was unaffected by treatment with NGF. Thus, the qualitatively similar effects of TPA and EGF seemed to be mediated through separate receptor systems with only the EGF receptor system reduced by NGF treatment. 相似文献
1000.
Myelin Gangliosides in Vertebrates 总被引:3,自引:3,他引:0
Frederick B. Cochran Jr. Robert K. Yu Robert W. Ledeen 《Journal of neurochemistry》1982,39(3):773-779
Abstract: A phylogenetic survey of brain myelin ganglioside patterns and concentrations has been carried out on 16 vertebrate species. Gangliosides were isolated from purified myelin and found to vary in concentration from 25 μg of sialic acid per 100 mg of myeh for goldfish to a value of 395 for turkey. The latter species had approximately equivalent amounts of GM1 and GM4 as the two major gangliosides. The 11 mammals studied all had GM1 as the major ganglioside, with variable amounts of GM4 ; rhesus monkey and human had 20-25% GM4 , whereas the others had less than 10%. Amphibia and fish myelin contained the least total ganglioside, with patterns that showed relatively little GM1 and no detectable GM4 . Alligator myelin was unique in having a total concentration as high as the avian species, but a pattern with predominantly diand trisialo gangliosides. 相似文献