PubMed Health⌕ Search

Biomedical subjects

A A Krichevskaia

Publications and source records attributed to A A Krichevskaia.

At least 19 recordsLinked to original sources
PubMed1989

[Interaction of products of su(Hw) and su(f) genes with MDG4 region regulating its transcription suppresses mutations in Drosophila caused by insertion of this gene].

The mdg4 (gypsy) mobile element of Drosophila contains two closely situated regions binding to proteins from nuclear extracts. One of these is an imperfect palindrome having homology with the lac operator of Escherichia coli, the other contains a reiterated sequence (5'PyPuTCTGCATACTPyPy) homologous to the octamer which is the core of many enhancers and upstream promoter elements. The transient expression of deletion mutants has shown that these DNA regions are negative and positive regulators, respectively, of mdg4 transcription. As was demonstrated earlier, mutations induced by the presence of mdg4 at different loci are suppressed, owing to either repression or activation of mdg4 transcription in Drosophila lines carrying unlinked mutations in su(Hw) or su(f) genes. We have shown that binding to a negative regulator (silencer) is weakened in nuclear extracts isolated from cell lines carrying su(f) mutations which activate mdg4 transcription; therefore, the su(f) gene codes for a protein capable of mdg4 repression. Furthermore, binding to a positive regulator is weakened in nuclear extracts isolated from cell lines carrying su(Hw) gene mutations which decrease the level of mdg4 transcription; hence, the su(Hw) gene encodes a protein which activates mdg4 transcription.

Animals↗
PubMed1988

[The Drosophila mobile element jockey, being a typical LINE, is transcribed from the internal promoter by RNA polymerase II].

Two polyadenylated transcripts of the jockey are detected at different stages of Drosophila melanogaster ontogenesis and in the cell culture. They have the same length as complete and deleted copies of jockey and correspond to the DNA strand containing open reading frames coding for polypeptides which are homologous to retroviral RNA-(DNA)-binding proteins and to their reverse transcriptases. The results of the experiments, where transcription was inhibited with alpha-amanitin in vivo, indicate that jockey is transcribed by RNA polymerase II. The analysis of expression of CAT constructions made on the basis of jockey, and the detection of a fixed site for transcription initiation in jockey genomic and transfected copies have shown that jockey transcription is controlled by an internal promoter located not farther than 12 nucleotides from the beginning of the element. Such an inward location of the promoter allows it to be preserved in replication via reverse transcription and accounts for the distribution of jockey and probably other LINEs throughout the genome. This is the case of the first internal promoter described for RNA polymerase II. The comparison of starting sequences of LINEs in Drosophila makes it possible to detect core sequences of such a promoter.

Amanitins↗
PubMed1987

[Biochemical indices of the sensitivity of cold-adapted animals to hyperoxic exposure].

It has been established that white rats adapted to the low temperature of the environment (45 days 2-4 degrees C) in contrast to the animals undergoing such action during 3 days (cold stress) show resistance to the toxic action of the high oxygen pressure. The considerable removal of convulsions under the action of oxygen, the absence of increase of erythrocyte membrane permeability in the preconvulsive stage of hyperoxia and prevention of changes in the substrate specificity of type A monoamine oxidase both in preconvulsive and convulsive periods of oxygen intoxication are their characteristics.

Adaptation, Physiological↗
PubMed1985

[Effect of the delta-sleep peptide on erythrocyte membrane function during low-temperature exposure].

3-day effect of low temperature increases the amount of extraerythrocyte hemoglobin by 64% in the blood serum, the activity of glucose-6-phosphatedehydrogenase increasing by 231%. Administration of 6.12 or 18 micrograms/100 g body weight of the delta-sleep peptide (DSIP) induces on change in amount of extraerythrocyte hemoglobin in the blood serum of intact rats. 6 micrograms/100 g DSIP increases the activity of glucose-6-phosphatedehydrogenase by 251.6%; 12 micrograms/100 g-- by 165.6%; 18 micrograms/100 g--by 90.6%. The normalizing effect on the level of extraerythrocyte hemoglobin and activity of glucose-6-phosphatedehydrogenase in low ambient temperature occurs at the dose of DSIP 12 micrograms/100 g body weight. The DSIP stabilizes the erythrocyte membranes in low temperature.

Animals↗
PubMed1985

[Homocarnosine in the brain of rats during cold adaptation].

24-hr effect of 2 degrees C-cold decreased the content of homocarnosin by 47.5% in the rat brain. 3-day effect decreased it by 51.2% and 7-day action decreased it by 62.2%. In cold-adapted rats (45 days) the homocarnosin content in the brain remains decreased by 56.5% and practically does not differ from the control level on the 7th day of cold-adaptation.

Adaptation, Physiological↗
PubMed1985

[Effect of arginine on the arginase activity and urea content of the brain and liver of rats acclimating to cold].

At cold stress (3 days exposition at 2--4 degrees C) the urea formation in rats brain and liver does not become more active, the content of extraerythrocytic hemoglobin and the total peroxydase activity increase in blood serum, the animals sensitivity to the action of hyperbaric oxygenation (HB0) grows. At cold adaptation (45 days at 2--4 degrees C) the urea content in tissues and the activity of arginase in liver increase, the concentration of extraerythrocytic hemoglobin and the total peroxydase activity normalize, animals become more resistant to HB0. Every day administration of arginine during 3-day cold effect makes the brain and liver arginase on 42 and 28% more active, increases the urea content on 26 and 19%, stabilizes the erythrocytic membranes. The animals protected by arginine against cold are more resistant to the action of HB0.

Acclimatization↗
PubMed1984

[Posttranslational deamidation of crystalline lens proteins during animal aging].

The amide content of total proteins and protein fractions (alpha-, beta-, gamma-cristallins and albuminoid) from cortex and nuclear lens zones of cattle has been investigated. The amide content in proteins of cortex and nuclear lens of young animals (1,5-2 years old) is the same. The decrease of the amide content in the proteins of nuclear lenz zone of old animals (6-12 years old) is due to fraction of readily hydrolysed amides. The data obtained prove the posttranslational desamidation of lens proteins at ageing. beta-Cristallines--the proteins with the highest amides content is exposed to posttranslational desamidation most of all.

Aging↗
PubMed1983

[Iron-containing proteins and the proteolytic activity in the blood serum in hyperbaric oxygenation and the protective action of urea].

The number and composition of ferro-containing proteins, the total number of iron, summary peroxidase activity and peptide-hydrolase activity have been determined under different hyperbaro-oxygenation (HBO) in blood serum. It has been established that under HBO the concentration of ferro-containing proteins increases, the fraction composition of serum and erythrocyte haemoglobin changes, the activity of acid peptide-hydrolases increases and the protamine-splitting peptide-hydrolase activity lowers. The administration of urea before HBO-experiments leads to the normalization of the most biochemical indicators of blood serum. The tests of oxygen intoxication depth assessment have been suggested.

Animals↗
PubMed1982

[Mechanisms of the effect of cold adaptation on the resistance to hyperoxia].

Hyperoxia after 3-day exposure at 2-4 degrees C induces more obvious disturbance of metabolites in rats than each of the factors separately. Along with decreased arginase activity in the brain and liver by 23 and 32% resp., the urine content decreases as well by 36 and 37% resp. Resistance of these animals against hyperoxia is reduced. But a preliminary 45-day cold-adaptation at 2-4 degrees C leads to a considerable activation of liver arginase and to increased content of urine in brain and liver by 32 and 30%, resp. The activation of arginase--urine system preserves under hyperoxia: the cold-adapted animals prove more resistant against hyperoxia effect. The above dynamic changes seem to be one of possible unspecific biochemical mechanisms of increasing the organism resistance against effects of extreme factors.

Adaptation, Physiological↗
PubMed1981

[Effect of low temperature on monoamine oxidase and substrate specificity in the mitochondrial fraction of rat brain].

Maintenance of animals for three days at 2 degrees C produces changes in the substrate specificity of type I monoamine oxidase (MAO). These changes manifest in serotonin and noradrenaline deamination and in a several-times increase in deamination of glucosamine, putrescine and gamma-aminobutyric acid. The cold-induced increase in AMP deamination is not related to MAE. The activity of type B MAO does not change on cold stress.

Animals↗
PubMed1981

[Cerebral and hepatic arginase and polyamines in the mechanisms of the protective effect of arginine in hyperoxia].

The effect of protective concentrations of arginine on the arginase activity and the content of rat brain and liver spermidine and spermine was studied under hyperoxia (6 atmospheres). Intraperitoneal injection of arginine to intact animals increases the arginase activity and the brain content of spermidine and spermine by 15, 19 and 25%, respectively. The liver arginase activity rises by 55%, while the level of the polyamines remains almost unchanged. Arginine injection before hyperoxic exposure prevents the significant lowering of the arginase activity and polyamine content seen in the unprotected animals. The relationship between the arginase activity and the polyamine level in the brain and liver is discussed with emphasis on arginine efficacy as protective agent in hyperoxia.

Animals↗
PubMed1981

[Monoamine oxidase activity in the brain during adaptation to cold and simultaneous exposure to cold and hyperbaric oxygenation].

One--day cold exposure decreases the monoamine oxidase type A activity by 52--54% (serotonin and noradrenaline substrates); the monoamine oxidase type B activity by 14%. Three--day cold exposure leaves the monoamine oxidase type B activity unchanged and decreases the monoamine oxidase type A activity by 29--32%; the enzyme of the latter type acquires the ability for deamination of glucosamine, putrescine and GABA. Under cold adaptation (45 days, 2 degrees C) the monoamine oxidase type A activity remains reduced as on the 3rd day, the type B activity decreases by 19%; enzyme substrate specificity does not change at all. Preliminary cold adaptation prevents alteration of the monoamine oxidase substrate specificity under hyperbaric oxygenation.

Acclimatization↗
PubMed1979

[Hemoglobin, transferrin and total iron content in the blood serum in hyperoxia and during the protective action of urea].

A rise of hemoglobin concentration accompanied by an increase of the total iron in the blood serum of white mice was found under oxygen pressure of 4 atm for an hour (preconvulsive state) and 6 atm (convulsive state). Changes in correlations of hemoglobin fractions in the blood serum were detected in both stages of oxygen poisoning by disc-electrophoresis in 7.5% polyacrylamide gel. A rise of transferrin concentration under these conditions (hyperoxia) was observed. The deflections occurred were less pronounced following administration of urea to the animals before hyperbaric oxygenation.

Animals↗
PubMed1978

[Nonenzymatic deamidation as a factor in protein aging].

Amidation of two protein fractions of brain, heart and liver of senite rats was found to decrease by 15--21% as compared with that of young animals. This decrease was shown to be due to unstable amide groups. Strong evidence is presented favouring the preposition that in proteins the unstable amide groups are those of asparagine and the stable ones those of glutamine. The possibility of the nonenzymatic deamidation of proteins was investigated. Deaminated proteins were found to be more easily attacked by proteinases which could be one of the possible ways of breakdown of aging proteins.

Aging↗
PubMed1977

[Investigation of rat brain prealbumins].

12 prealbumines of rat brain water-soluble fraction were studied. Neither lipid components nor carbohydrate ones were found out in the proteins. Three of the proteins appeared to be RNA-proteids. Their subcellular distribution was investigated. The effects of temperature, salts, acids and ethanol on disc electrophoretic spectrum of brain prealbumines were closely observed. The amino acid composition, properties, compartmentation, tissue and species specificity of one of the prealbumines were studied in detail. The protein is marked as BTB-protein, as it migrates under disc electrophoresis in 7,5% polyacrylamide gel with the "witness" front of bromothemol blue (BTB). The content of BTB-protein is 0.06--0.08 gr per 100 gr of wet tissue. The protein is RNA-proteid. Its molecular weight is 10,000--20,000. BTB-protein contains 42 mole % of acidic amino acids and 5.4 mole % of alkaline ones. The protein was found in nuclear and cytoplasmic fractions. It is mainly an all-organs protein. Small amount of this protein is found in blood serum. BTB-protein can be found on the disc electrophoregramms of embryo and newborn rats brain proteins, as well as of the brain of other mammals, birds and amphibia. BTB-protein is resistant to boiling and to the effects of salts, acids, ethanol. It is suggested that BTB-protein has heterogenous structure and may be of neurophysin nature.

Amino Acids↗