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41.
Long-term potentiation and depression of synaptic transmission have been considered as cellular mechanisms of memory in studies conducted in recent decades. These studies were predominantly focused on mechanisms underlying plasticity at excitatory synapses. Nevertheless, normal central nervous system functioning requires maintenance of a balance between inhibition and excitation, suggesting existence of similar modulation of glutamatergic and GABAergic synapses. Here we review the involvement of G-protein-coupled receptors in the generation of long-term changes in synaptic transmission of inhibitory synapses. We considered the role of endocannabinoid and glutamate systems, GABAB and opioid receptors in the induction of long-term potentiation and long-term depression in inhibitory synapses. The preand postsynaptic effects of activation of these receptors are also discussed. 相似文献
42.
E. Reynaud V. N. Bolshakov V. Barajas F. C. Kafatos M. Zurita 《Molecular genetics and genomics : MGG》1997,256(4):462-467
The Drosophila melanogaster homologue of the Anopheles gambiae C3 cDNA has been isolated and characterized by sequence analysis. The encoded protein was localized by immunochemical and immunocytochemical methods. The Drosophila C3 protein is highly similar to homologues of disputed function, which have previously been identified in fungi, plants and animals. The protein is ubiquitous and localized in the cytoplasm. Cell fractionation followed by detection with a specific antibody preparation shows that the protein is associated with the 40S ribosomal subunit. The C3 gene is located in section 101F of chromosome 4. Antisense transgenic analysis shows that this gene is essential for oogenesis. The most prominent phenotype resulting from antisense depletion of C3 RNA is disappearance of the follicular cells of the ovary (where the concentration of C3 protein is normally high) and abnormalities of the associated germline derivatives, leading to failure of egg production. 相似文献
43.
Rafael AP Guércio Anna Shevchenko Andrej Shevchenko Jorge L López-Lozano Jaime Paba Marcelo V Sousa Carlos AO Ricart 《Proteome science》2006,4(1):11-14
Background
Bothrops atrox is responsible for the majority of snakebite accidents in the Brazilian Amazon region. Previous studies have demonstrated that the biological and pharmacological activities of B. atrox venom alter with the age of the animal. Here, we present a comparative proteome analysis of B. atrox venom collected from specimens of three different stages of maturation: juveniles, sub-adults and adults. 相似文献44.
I. F. Zhimulev E. S. Belyaeva O. V. Fomina M. O. Protopopov V. N. Bolshakov 《Chromosoma》1986,94(6):492-504
A new genetic model system for studying position effect variegation in Drosophila melanogaster was found. It allows the analysis of genetic inactivation and changes in chromosome morphology in the same cells. In T(1;2)dor
var7 strains the 2B5 early ecdysone puff, and the ecs locus which maps in this puff are translocated into the vicinity of centromeric heterochromatin. The ecs locus plays a key role in the system of ecdysone puffs: genetic damage to this locus results in loss of sensitivity of cells to the hormone and, as a consequence, ecdysone-induced puffs do not develop. In the T(1;2)dor
var7 chromosome the ecs and at least five adjoining loci are inactivated in a variegated fashion. In the salivary gland cells of T(1;2)dor
var7/ ecslt435 0 h prepupae which do not show the ecdysone puffs, the morphology of the 2B region was analysed. In all cases where the ecs locus was inactivated, a dense block of chromatin reminiscent of a solid band was found in the 2B region instead of the four bands 2B1–2, 3–4, 5 and 6. Sometimes compaction of the chromatin reached the 2A1–2 or even 1E1–4 bands. Formation of the compact block of chromatin coincided with late replication in this region. In situ hybridization of polytene chromosomes with a DNA clone from the ecs locus showed that when the dense chromatin block was present, no DNA was accessible for hybridization in 2B5. Hybridization of DNA of another clone located in the region of the translocation breakpoint (2B7–8) was found only in polytene chromosomes of larvae grown at 25° C, and never in those grown at 18° C, independently of the morphology of the 2B5 puff. The possibility that in the case of block formation both late replication and, as a consequence, underreplication of chromosome DNA take place, is discussed.Dedicated to Professor W. Beermann on the occasion of his 65th birthday 相似文献
45.
46.
A. G. Vasil’ev V. N. Bolshakov N. G. Evdokimov N. V. Sineva 《Doklady biological sciences》2016,468(1):118-121
The ecological “compensation principle” enunciated by Yu.I. Chernov, who suggested a higher level of compensatory diversity in communities depleted in composition, proved to be also applicable to a single population, as demonstrated in a model rodent species, mole vole with mono- and polymorphic coat color, using the methods of geometric morphometrics. The mandible shape diversity was significantly increased in the monomorphic as compared to polymorphic populations, in which the division of foraging activities between animals of different morphs led to a suppression of general morphological diversity. 相似文献
47.
48.
The relative amount of DNA in defined segments of salivary gland chromosomes of Drosophila melangogaster from the Oregon R stock was determined by autoradiography. The data obtained were then used to estimate the possible correlation between DNA content and the degree of manifestation of charcters such as weak-point behavior, late replication, strong synapsis, breaks of chromosome rearrangements, hybridization with cRNA, and localization of mobile elements. Of 380 regions investigated 274 have showed deviations in the degree of manifestation of these features from that predicted on the basis of the DNA content of these regions. Regions, previously shown to consist of intercalary heterochromatin (IH, Zhimulev et al. 1982), were found to have a significantly higher frequency of the simultaneous manifestation of several of the above-mentioned features, with the exception of localization of mobile elements. These findings support the earlier suggestion that a high frequency and a simultaneous manifestation of IH features depend on some peculiarities of the molecular organization of IH regions, but not on a high DNA content. 相似文献
49.
Bolshakov IA Vygodina TV Gennis R Karyakin AA Konstantinov AA 《Biochemistry. Biokhimii?a》2010,75(11):1352-1360
An iron-hexacyanide-covered microelectrode sensor has been used to continuously monitor the kinetics of hydrogen peroxide
decomposition catalyzed by oxidized cytochrome oxidase. At cytochrome oxidase concentration ≈1 μM, the catalase activity behaves
as a first order process with respect to peroxide at concentrations up to ≈300–400 μM and is fully blocked by heat inactivation
of the enzyme. The catalase (or, rather, pseudocatalase) activity of bovine cytochrome oxi- dase is characterized by a second
order rate constant of ≈2•102 M-1•sec-1 at pH 7.0 and room temperature, which, when divided by the number of H2O2 molecules disappearing in one catalytic turnover (between 2 and 3), agrees reasonably well with the second order rate constant
for H2O2-dependent conversion of the oxidase intermediate FI-607 to FII-580. Accordingly, the catalase activity of bovine oxidase may be explained by H2O2 procession in the oxygen-reducing center of the enzyme yielding superoxide radicals. Much higher specific rates of H2O2 decomposition are observed with preparations of the bacterial cytochrome c oxidase from Rhodobacter sphaeroides. The observed
second order rate constants (up to ≈3000 M-1•sec-1) exceed the rate constant of peroxide binding with the oxygen-reducing center of the oxidized enzyme (≈500 M-1•sec-1) several-fold and therefore cannot be explained by catalytic reaction in the a
3/CuB site of the enzyme. It is proposed that in the bacterial oxidase, H2O2 can be decomposed by reacting with the adventitious
transition metal ions bound by the polyhistidine-tag present in the enzyme, or by virtue of reaction with the tightly-bound
Mn2+, which in the bacterial enzyme substitutes for Mg2+ present in the mitochondrial oxidase. 相似文献
50.
Audrey Leprince Mark WJ van Passel Vitor AP Martins dos Santos 《Current opinion in biotechnology》2012,23(5):651-658
Highlights? Top-down and bottom-up approaches to genome streamlining. ? Computational support for constructing and refactoring streamlined genomes. ? From genome engineering to metabolic reprogramming. ? Perspectives in applied genome engineering. 相似文献