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91.
Cytosolic isocitrate dehydrogenase in humans, mice, and voles and phylogenetic analysis of the enzyme family 总被引:3,自引:0,他引:3
Nekrutenko A; Hillis DM; Patton JC; Bradley RD; Baker RJ 《Molecular biology and evolution》1998,15(12):1674-1684
In this study, we report cDNA sequences of the cytosolic NADP-dependent
isocitrate dehydrogenase for humans, mice, and two species of voles
(Microtus mexicanus and Microtus ochrogaster). Inferred amino acid
sequences from these taxa display a high level of amino acid sequence
conservation, comparable to that of myosin beta heavy chain, and share
known structural features. A Caenorhabditis elegans enzyme that was
previously identified as a protein similar to isocitrate dehydrogenase is
most likely the NADP-dependent cytosolic isocitrate dehydrogenase enzyme
equivalent, based on amino acid similarity to mammalian enzymes and
phylogenetic analysis. We also suggest that NADP-dependent isocitrate
dehydrogenases characterized from alfalfa, soybean, and eucalyptus are most
likely cytosolic enzymes. The phylogenetic tree of various isocitrate
dehydrogenases from eukaryotic sources revealed that independent gene
duplications may have given rise to the cytosolic and mitochondrial forms
of NADP-dependent isocitrate dehydrogenase in animals and fungi. There
appears to be no statistical support for a hypothesis that the
mitochondrial and cytosolic forms of the enzyme are orthologous in these
groups. A possible scenario of the evolution of NADP-dependent isocitrate
dehydrogenases is proposed.
相似文献
92.
Mitogenic properties of the insulin derived from pig brain were compared with the action of pancreatic (standard) pig insulin and epidermal growth factor (EGF) using the culture of Swiss 3T3 cells. The brain insulin, likely as the pancreatic insulin, induced uptake of 14C-thymidine by resting cells in a dose-dependent manner at concentration of 0.5-2.0 micrograms/ml in culture medium. However, at equal concentrations of these hormones the proliferating effect of the brain insulin appeared to be 2-fold higher than the effect of the pancreatic hormone. At the same time the mitogenic action of both hormones was lower than that of EGF (10 ng/ml). The additive effect of the brain insulin and EGF, administered in combination, was more pronounced than the effect of the pancreatic insulin combined with EGF. The data obtained suggest a possible participation of brain insulin in the process of nerve cell proliferation. 相似文献
93.
This article further develops a statistical/stereological model for estimating 3-dimensional population characteristics of cell elements based on analysis of random (2-dimensional) cross section of planes. This model was used to conduct morphometric electron microscope research on presynaptic terminals (PT) at lateral sites at the base of the dorsal horn of the cat spinal cord. Estimated distributions of PT volumes were thus found, as well as areas of PT axolemma with "corrugation" size of synaptic zones (AZ), and estimates of mean numbers of AZ on a 3-dimensional PT and statistical parameters of AZ location in relation to the point at which the axon passes into the synaptic bouton.Dnepropetrovsk State University. A. A. Bogomolets Institute of Physiology, Academy of Sciences of the Ukrainian SSR, Kiev. Translated from Neirofiziologiya, Vol. 22, No. 6, pp. 803–811, November–December, 1990. 相似文献
94.
NGF and Neurotrophin-3 Both Activate TrkA on Sympathetic Neurons but Differentially Regulate Survival and Neuritogenesis 总被引:9,自引:1,他引:8
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Daniel J. Belliveau Irena Krivko Judi Kohn Christian Lachance Christine Pozniak Dmitri Rusakov David Kaplan Freda D. Miller 《The Journal of cell biology》1997,136(2):375-388
In this report we examine the biological and molecular basis of the control of sympathetic neuron differentiation and survival by NGF and neurotrophin-3 (NT-3). NT-3 is as efficient as NGF in mediating neuritogenesis and expression of growth-associated genes in NGF-dependent sympathetic neurons, but it is 20–40fold less efficient in supporting their survival. Both NT-3 and NGF induce similar sustained, long-term activation of TrkA, while NGF is 10-fold more efficient than NT-3 in mediating acute, short-term TrkA activity. At similar acute levels of TrkA activation, NT-3 still mediates neuronal survival two- to threefold less well than NGF. However, a mutant NT-3 that activates TrkC, but not TrkA, is unable to support sympathetic neuron survival or neuritogenesis, indicating that NT3–mediated TrkA activation is necessary for both of these responses. On the basis of these data, we suggest that NGF and NT-3 differentially regulate the TrkA receptor both with regard to activation time course and downstream targets, leading to selective regulation of neuritogenesis and survival. Such differential responsiveness to two ligands acting through the same Trk receptor has important implications for neurotrophin function throughout the nervous system. 相似文献
95.
O. L. Berezovskaya D. A. Rusakov G. G. Skibo A. V. Bulavka J. -F. Leterrier 《Neurophysiology》1995,27(1):1-7
Interaction between neurofilaments and mitochondria was studied on the model of cultured hippocampal cells of newborn rats. A treatment by specific toxins -iminodipropionitril or hexanedione resulted in a disintegration and translocation of neurofilaments in the cultured neurons. These effects were accompanied by a considerable decrease in dimensions of mitochondria, an increase in their elongation coefficient, a noticeable increase in spatial density of these organelles, and their translocation within the perinuclear layer of cytoplasm. The role of neurofilaments in the intraneuronal distribution of mitochondria and modifications of their functional state is discussed. The neurofilament system is supposed to considerably influence the processes of division, growth, and translocation of the mitochondria.Neirofiziologiya/Neurophysiology, Vol. 27, No. 1, pp. 3–10, January–February, 1995. 相似文献
96.
The 3D structure of the heart tissue of Wistar rats from different age groups has been reconstructed by light microscopy of consecutive series of semithin sections. At the histological resolution level, connective tissue segments in the myocardium of aged (18 months) animals were found, while in the myocardium of young (2 months) animals no connective tissue segments were observed. A mathematical model and the results of the 3D reconstruction were used to simulate the formation of excitation wave circulation in the myocardium. The values of conductivity and the excitability threshold, and the pulse frequency rates were found at which the disturbances of the heart rhythm resulting from the excitation wave circulation are predicted by the mathematical modeling. 相似文献
97.
Jeroen Lakerveld Sandra DM Bot Marijke J Chinapaw Maurits W van Tulder Patricia van Oppen Jacqueline M Dekker Giel Nijpels 《BMC endocrine disorders》2008,8(1):1-11
Background
Insulin resistance and diabetes are associated with increased oxidative stress and impairment of cellular defence systems. Our purpose was to investigate the interaction between glucose metabolism, antioxidative capacity and heat shock protein (HSP) defence in different skeletal muscle phenotypes among middle-aged obese subjects during a long-term exercise and dietary intervention. As a sub-study of the Finnish Diabetes Prevention Study (DPS), 22 persons with impaired glucose tolerance (IGT) taking part in the intervention volunteered to give samples from the vastus lateralis muscle. Subjects were divided into two sub-groups (IGTslow and IGTfast) on the basis of their baseline myosin heavy chain profile. Glucose metabolism, oxidative stress and HSP expressions were measured before and after the 2-year intervention.Results
Exercise training, combined with dietary counselling, increased the expression of mitochondrial chaperones HSP60 and glucose-regulated protein 75 (GRP75) in the vastus lateralis muscle in the IGTslow group and that of HSP60 in the IGTfast group. In cytoplasmic chaperones HSP72 or HSP90 no changes took place. In the IGTslow group, a significant positive correlation between the increased muscle content of HSP60 and the oxygen radical absorbing capacity values and, in the IGTfast group, between the improved VO2max value and the increased protein expression of GRP75 were found. Serum uric acid concentrations decreased in both sub-groups and serum protein carbonyl concentrations decreased in the IGTfast group.Conclusion
The 2-year intervention up-regulated mitochondrial HSP expressions in middle-aged subjects with impaired glucose tolerance. These improvements, however, were not correlated directly with enhanced glucose tolerance. 相似文献98.
Background
Life Science Identifiers (LSIDs) are persistent, globally unique identifiers for biological objects. The decentralised nature of LSIDs makes them attractive for identifying distributed resources. Data of interest to biodiversity researchers (including specimen records, images, taxonomic names, and DNA sequences) are distributed over many different providers, and this community has adopted LSIDs as the identifier of choice. 相似文献99.
M Ozkan SG Desai Y Zhang DM Stevenson J Beane EA White ML Guerinot LR Lynd 《Journal of industrial microbiology & biotechnology》2001,27(5):275-280
Characteristics of 13 newly isolated thermophilic, anaerobic, and cellulolytic strains were compared with previously described
strains of Clostridium thermocellum: ATCC 27405 and JW20 (ATCC 31549). Colony morphology, antibiotic sensitivity, fermentation end-products, and cellulose degradation
were documented. All 13 strains were sensitive to erythromycin (5 μg/ml) and chloramphenicol (25 μg/ml), and all strains but
one were sensitive to kanamycin (20 μg/ml). Polymerase chain reaction (PCR) amplification using primers based on gene sequences
from C. thermocellum ATCC 27405 was successful for all 13 strains in the case of the hydrogenase gene and 11 strains in the case of phosphotransacetylase/acetate
kinase genes. Ten strains amplified a product of the expected size with primers developed to be specific for C. thermocellum 16SrRNA primers. Two of the 13 strains did not amplify any product with the PCR primers designed for the phosphotransacetylase/acetate
kinase and 16SrRNA primers. A MboI-like GATC- recognizing restriction activity was present in all of the five strains examined. The results of this study have
several positive implications with respect to future development of a transformation system for cellulolytic thermophiles.
Journal of Industrial Microbiology & Biotechnology (2001) 27, 275–280.
Received 12 September 2000/ Accepted in revised form 20 November 2000 相似文献
100.
D. A. Rusakov Ming-Yuan Min G. G. Skibo L. P. Savchenko M. G. Stewart D. M. Kullmann 《Neurophysiology》1999,31(2):79-81
Experiments on hippocampal slices showed that perfusion with a dextran solution more effectively facilitates AMPA-mediated
transmission in structurally complex synapses of mossy fibers of Shaffer collaterals. Estimates for changes in the extracellular
Ca2+ concentration in the close vicinity of a reconstructed synapse during the action potential development are obtained. The
results together with data about the rather small (0.5 μm) characteristics distance between neighboring synapses showed that
the probability of mutual intersynaptic influence via the microenvironment is high. A probable functional role of such influences
is discussed. 相似文献