Succinate dehydrogenase activity in the wall of rabbit aorta

Summary An investigation of succinate dehydrogenase activity in the wall of rabbit aorta was carried out. The level of succinate dehydrogenase per se in the smooth muscle cells was found to be fairly high, while the mitochondrial level of carrier CoQ was low. The latter may explain the low level or lack of activity of succinate dehydrogenase in these cells as noticed by previous authors.A reliable image of the actual level of succinate dehydrogenase was obtained only by adding CoQ₁₀ to the incubation system. PMS should be avoided, as it induced a Nothing dehydrogenase reaction even at low concentrations.     

Succinate dehydrogenase activity of Escherichia coli cells after heat stress and during the reparative process

The resting cells of different E. coli cells remained viable after their heating at 48 degrees C for 30 min. The activity of their succinate dehydrogenase (SDH) (EC 1.3.99.1) was not more than 50% of the control one. When the cells were inoculated after a heat stress into a peptone medium, they started to grow at a high rate. However, their maximal specific growth rate mu and the overall biomass yield were less than in the control. The SDH activity of the cells reached the original level by the end of the logarithmic growth phase. This did not happen when the cells were incubated in 0.14 M NaCl for a time necessary for the culture to reach the end of the logarithmic growth phase. The SDH activity (in absolute values) of cell-free extracts was not greater than 35% of the cell SDH activity. The SDH activity of the cell-free extracts did not change after their heating at 48 degrees C. The SDH activity of E. coli cells is recommended to be used as a parameter indicative of their stress state.     

Succinate dehydrogenase activity in the developing molar of the hairless mouse Mus musculus

Synopsis Succinate dehydrogenase activity in the odontogenic tissues of the hairless mouse (hr/hr) has been studied from the initiation of the dental lamina through apposition. Enzyme activities were designated as negative, slight, moderate and strong as a function of intensity of the reaction product. Enzyme levels in the odontogenic tissues increased with advancing tooth morphogenesis. Greatest activity was observed in the ameloblastic layer which peaked on the fourth to sixth postnatal days. This cell layer displayed higher enzyme activity than the ectomesenchymally-derived odontoblasts. Succinate dehydrogenase activity appeared to be related to the degree of differentiation and functional competence on the odontogenic tissues of the hairless mouse.     

Succinate dehydrogenase mutant of Rhizobium meliloti.

A succinate dehydrogenase mutant strain of Rhizobium meliloti was isolated after nitrosoguanidine mutagenesis. It failed to grow on succinate, glutamate, acetate, pyruvate, or arabinose but grew on glucose, sucrose, fructose, and other carbohydrates. The mutant strain showed delayed nodulation of lucerne plants, and the nodules were white and ineffective. A spontaneous revertant strain of normal growth phenotype induced red and effective nodules.     

Succinate dehydrogenase activity in the developing molar of the Mongolian gerbilMeriones unguiculatus

Synopsis The distribution of succinate dehydrogenase in the odontogenic tissues in the Mongolian gerbil, ranging in age from 18 days prenatal to 8 days postnatal, was studied. Activity levels were designated negative, trace, slight, moderate, strong and very strong, dependent upon visual observations. The results indicated increased levels of activity as the tissue layers differentiated from the lamina stage through early apposition. The cell layer displaying the most succinate dehydrogenase activity was the ameloblastic layer while the stratum intermedium layer was the, next most active cell layer. Succinate dehydrogenase activity appeared to be related to the degree of differentiation and functional competency of the odontogenic tissues in the Mongolian gerbil.     

Succinate dehydrogenase activity in various parts of the rat heart in systole and diastole

After fixation of the rat heart at the state of systole and diastole, succinate dehydrogenase (SDH) activity has been revealed. In distributions of the muscle fibers according to their optic density, statistic characteristics connected with the first four moments have been taken into consideration. SDH activity is different in five cardiac parts. Individual changeability is more pronounced in the all cardiac parts at diastole. In comparison to the internal one at systole, it is lower in the all parts, and at diastole--in the atria only. The ratio of the internal and individual changeability is in such a state, that it should be taken into account in all statistical calculations, connected with SDH activity determination in cardiomyocytes.