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991.
992.
Location and nucleotide sequence of frdB, the gene coding for the iron-sulphur protein subunit of the fumarate reductase of Escherichia coli 总被引:30,自引:0,他引:30
S T Cole T Grundstr?m B Jaurin J J Robinson J H Weiner 《European journal of biochemistry》1982,126(1):211-216
The frdB gene, encoding the iron-sulphur protein subunit of fumarate reductase, has been located and its complete nucleotide sequence determined. The identity of the gene was confirmed by protein chemical studies and determination of the NH2-terminal sequence of the FrdB protein. The frdB gene is situated distal to and partially overlapped by frdA which codes for the flavoprotein subunit of the reductase. Its reading frame contains 244 codons and predicts a protein of Mr 27092. In composition, the FrdB protein is strikingly similar to the corresponding subunit of the related flavoenzyme, succinate dehydrogenase. Analysis of the protein's primary structure revealed several features characteristic of iron-sulphur proteins. 相似文献
993.
On the basis of the early results of the use of intradiscal injection of chymopapain in 15 patients with degenerative lumbar disc disease, the following statements are warranted: The injection can be beneficial in selected patients with lumbar disc disease. The relief of leg symptoms seems to be more striking than that of the accompanying low back symptoms although both are apparent. The exact mechanism by which pain is relieved is still obscure, but helpful information has been obtained from the early results of this investigation. The failure of chymopapain in carefully selected patients has resulted in only a brief time delay in operative intervention. 相似文献
994.
Three behavioral tests, spontaneous locomotor activity (SLMA), exploratory behavior (EB) and rotarod performance (RP), a measure of neuromuscular coordination, were used to study the interaction of PGE1 (1 mg/kg i.p., 10 min. pretreatment) with DBcAMP (25 mg/kg i.p., 25 min. pretreatment) in mice. A dose-response relationship of PGE1 (0.01–5.0 mg/kg) to SLMA was determined, with a significant decrease in SLMA produced by a dose of 0.1 mg/kg. Decreases in SLMA were produced by PGE1 (79%), DBcAMP (41%) and DBcAMP-PGE1 combination (71%). Similar decreases in EB were observed. Although no significant difference between controls and DBcAMP was observed in RP, 52% of mice tested were RP failures following PGE1 and a 100% failure rate was induced by the combination. Mice were treated with a second injection of DBcAMP or PGE1 or the combination 24 hr following the first injection. Behavioral activity of these mice was observed 25 min (DBcAMP) or 10 min (PGE1) after the second dose was administered. A second injection of DBcAMP failed to decrease SLMA and EB from controls; moreover, SLMA began to return towards control levels as early as 2 hr between injections. The second injection of PGE1 or DBcAMP+PGE1 produced the same behavior as that produced by the first injection. On the basis of these results, the relationship of cyclic nucleotides and PGs to behavioral activity is discussed. 相似文献
995.
996.
The hemispheric asymmetry of brain activity is well established, and there in increasing evidence of a relationship between phenomena of asymmetry and personality, arousal status, and the existence of mental and emotional disease.Differences in individual sensitivity to drugs may relate to hemispheric asymmetric patterns. Several mechanisms may contribute to the unequal influence of systematically administered drugs on each hemisphere, including effect of hemispheric activity status on 1) speed and degree of local uptake of drug; 2) differential in synaptic sensitivity; 3) degree of competition with local endogenous neurohumors.Adequate knowledge concerning normal and abnormal hemispheric asymmetry, and the effects of spontaneous or manipulative changes in the activity of each hemisphere should lead to more rational and effective choices and patterns of administration of therapeutic agents. 相似文献
997.
Timing of swarmer cell cycle morphogenesis and macromolecular synthesis by Hyphomicrobium neptunium in synchronous culture. 总被引:4,自引:4,他引:0 下载免费PDF全文
The swarmer cycle of Hyphomicrobium neptunium consists of a temporal sequence of discrete developmental events. To time morphogenesis and to investigate modulations in macromolecular synthesis, we attempted methods for synchronous culture. During synchrony, swarmer maturation occurred over 32%, hyphal growth occurred over 36%, and bud maturation occurred over 32% of the time required to complete the swarmer cycle. Daughter cells were released after 265 min. Deoxyribonucleic acid replication was discontinuous, having a G1 period of approximately 180 min. In addition, ribonucleic acid and protein syntheses were depressed during the earlier phases of development. 相似文献
998.
999.
Thirty forest bird communities were studied with regard to the changes in structural indices (number of species, density, biomass, species diversity H') and in energetics (energy flow A, production P, ecological efficiency P/A) in temporal and spatial gradients. All these characteristics increase during temporal succession; in natural deciduous forest there is a two-peak pattern of the increase, with the maximum in 15–20 yr old forest ("time ecotone"; A = 692.9 Megajoules ha−1 season−1 , H'= 4.2 bits), In artificially managed pine forest these indices rise monotonically, reaching a maximum in sub-climax (A = 426.2 MJ ha−1 season−1 , H'= 4.2 bits). In a deciduous forest a tendency exists to decrease the ecological efficiency (from 8% to 2%), while in a coniferous stand this variable remains low (2%) and almost constant during succession. In a spatial gradient, the highest values of energy flow and species diversity occur in forest stands with moderate soil/water regime and of ecotonal character (A = 851.2 MJ ha−1 season−1 , H'= 4.5 bits). All mature forest bird communities show similar values of diversity (4.2–4.5 bits) and ecological efficiency (appr. 2%), though they differ in the rate of energy flow. The relation of these findings to the current concepts of ecological succession are discussed. 相似文献
1000.
A simple experimental demonstration is described to show that photon correlation spectroscopy can be used to measure simultaneously the diffusion coefficient and, by the Doppler effect, the sedimentation coefficient of a small suspended particle. Calculation shows that the method should be readily extendable to particles with sedimentation coefficients of 5 S. 相似文献