Ciliary activity under normal conditions and under viscous load

Ciliary metachronism and motility were examined optically in muco-ciliary tissue cultures from three different systems: a) frog's palate epithelium, b) frog's oesophagus, and c) human nasal polyps. In addition, lateral cilia of Mytilus edulis (water transporting cilia) were examined. It was revealed that the degree of synchronization between muco-ciliary systems is lower than that of water transporting cilia. There are no significant differences between different muco-ciliary systems, within the accuracy of our measurement although relatively large statistical ensembles were used. In addition the wavelength and wave direction of the metachronal wave was examined. All four systems exhibit similar wavelength. The metachronal parameters of muco-ciliary systems exhibit fluctuations (as was demonstrated by the degree of synchronization), however, the magnitude and repetitivity of these fluctuations, is dependent on the loading of the ciliary system. We have loaded the system by increasing the viscosity of the medium. Under viscous load the frequency of the beating decreased. The metachronal wavelength became longer and the metachronal coordination type more orthoplectic.     

Effect of NMDA receptor activity on histone H3 methylation and its asymmetry in the hippocampal pyramidal neurons of rats with different excitability thresholds under normal and stress conditions

Process of methylation of histone H3 for lysine 4 (H3K4) was studied in hippocampal pyramidal neurons of rats—intact and submitted to emotional-pain stress with active and inactivated channels of NMDA-receptors with taking into account the interhemisphere lateralization and in connection with the genetically determined level of excitability of the animals’ nervous system. There were revealed interstrain differences in the basal level of the H3K4 methylation whose direction depends on structural-functional peculiarities of hippocampal fields and lateralization. Under action of stress the direction of the observed changes in the degree of the H3K4 methylation depended on the functional states of channels of NMDA-receptors. On the background of active receptors the proportion of immunopositive cells predominantly increased. In the CA1 field this change was not connected with excitability and lateralization, whereas in the CA3 field it had a complex character and depended on these two factors. At inactivation of channels of NMDA-receptors the portion of immunopositive nuclei as a result of the stress action, on the contrary, predominantly decreased; interstrain specificity of these changes was connected with lateralization, while its direction in different hippocampal fields was different. Action of the short-time emotional-pain stress did not lead to a change of shape of interhemisphere at active state of receptors, whereas at inactivation of receptors it changes depending on the structural-functional organization of hippocampus and on excitability of the nervous system.     

Effects of juvenile hormone and 20-hydroxyecdysone on alkaline phosphatase activity in Drosophila under normal and heat stress conditions

The effect of 20-hydroxyecdysone (20E) and the juvenile hormone (JH) on the activity of the alkaline phosphatase (ALP) has been studied in young females of wild-type Drosophila virilis and Drosophila melanogaster under normal conditions and under heat stress (38 degrees C). Both 20E feeding of the flies and JH application led to a substantial rise in ALP activity. ALP activity was also measured in young females of a JH-deficient strain of D. melanogaster, apterous(56f). A decrease in the enzyme activity was observed in the mutant females as compared to wild type. A rise in JH and 20E levels was found not to prevent the response of ALP to heat stress, but to change its stress-reactivity. Mechanisms of regulation of dopamine (DA) level by gonadotropins in Drosophila are discussed.     

Globulin transport in the microcirculatory system under normal and stress conditions

Biomicroscopic studies of rat mesentery during 24-hours immobilization have shown phasic changes in globulin-FITC transport in the system: venule-interstitial-lymphatic microvessel. During short immobilization we have discovered the increasing contraction of lymphatic microvessels; during long immobilization--the decreasing contraction has been discovered.     

The activity of Krebs cycle enzymes in the visual analyzer of normal rats and under stress]

In the visual analyzer of the intact animals higher activity of NAD-dependent dehydrogenases of tricarbonic acids cycle is observed in the retina and of FAD-dependent dehydrogenases in the occipital brain lobes. The influence of stress by Desiderato method elicits compensatory increase of the succinatedegidrogenase activity. The acute stress elicits a change of regulation of the activity of dehydrogenase of tricarbonic acids cycle, estimated by the reaction to functional load. Animals staying in the darkness after stress promotes restoration of the tricarbonic acids cycle of the enzymes activity up to the normal level.     

Oxidative stress in normal and diabetic rats.

Parameters related to oxidative stress were studied in a group of 10 Wistar diabetic rats and 10 control rats. The levels of total erythrocyte catalase activity in the diabetic animals were significantly (p<0.001) greater than the control levels. The diabetic animals presented an amount of vitamin E far greater (p<0.0001) than the controls, as was also the case for the vitaminE/polyunsaturated fatty acid (PUFA) and vitaminE/linoleic acid (C18:2) ratios. Greater vitaminE/triglyceride (TG) ratio, however, appeared in the control group. The corresponding vitamin A ratios (vitaminA/TG, vitaminA/PUFA, vitaminA/C 18:2) were higher in the control group. Our work corroborates the findings that fatty acid metabolism presents alterations in the diabetes syndrome and that the antioxidant status is affected.     

Effect of different carbohydrates on in vitro fermentation activity and bacterial numbers of porcine inocula under osmotic stress conditions

The bacteria of the intestine have to cope with varying osmotic conditions in their ecosystem. In this in vitro study, the modified Hohenheim gas test (HGT) was used to determine fermentation activity and bacterial composition of pig's faecal microbial inoculum, when fermenting different carbohydrates (inulin, corn starch, potato starch, cellulose, pectin), under normal buffered and osmotic stress conditions (elevated medium salinity). After 24 h of fermentation, gas, ammonia and short-chain fatty acid (SCFA) production was measured, and the cell numbers of total eubacteria, Lactobacillus spp., Bifidobacterium spp. and enterobacteria were analysed, using real-time polymerase chain reaction. There was a significant reduction in gas production after 24 h when comparing osmotic stress conditions with normal buffered conditions, and there were also differences among carbohydrates under both conditions. The content of SCFA was significantly lower when comparing osmotic stress with normal buffered conditions. Under osmotic stress, inulin and corn starch increased (p < 0.05) cell numbers of total eubacteria, while Bifidobacterium spp. and enterobacteria were higher (p < 0.05) when corn starch and pectin were fermented, respectively, in comparison to the other carbohydrates. The in vitro system of the modified HGT appears to be suitable to scrutinise effects of carbohydrates on the metabolic activity and composition of the microbial community under osmotic stress conditions, as they might occur during situations of osmotic diarrhoea.     

Seasonal dynamics of cellular mitotic activity in the adenohypophysis and adrenal cortex of normal rats and under the stress reaction

The experiments have been performed in 162 white non-inbred male rats. The animals are sacrificed on the third week of every month between 11 A. M. and 13 P. M. Some essential changes in the mitotic coefficient (MC) are noted in the organs of the hypophysis-adrenal system during 1 year. In the intact rats adenohypophysis the MC reaches its maximum in March, and in September in drops to its minimal value. In the glomerular and the fascicular-retinal zones of the intact animal adrenal cortex, two periods with an elevated mitotic activity are noted during the annual cycle (in spring and in autumn). Formalin stress produces a decrease in the adenohypophysis, and in the fascicular-retinal zone of the adrenal cortex--an increase of the MC. In the fascicular-retinal zone there is not any reaction only in May and June. Perhaps, the reason is in some seasonal changes of reactivity of the zone mentioned to ACTH. The seasonal dynamics of the MC in the hypophysis-adrenal system organs is in general maintained under the stress.     

Degradation of Cdc25A phosphatase in HeLa cells under normal and stress conditions

Cdc25A phosphatase regulates cell cycle progression by removing the inhibitory phosphates from cyclin-dependent kinases. Activity of Cdc25A depends on its phosphorylation status. During normal cell cycle progression and after DNA damage phosphorylation by Chk1 (or Chk2) triggers Cdc25A degradation via ubiquitin-proteasome pathway. In this study we investigate the role of various phosphorylation sites (Ser123, Ser75, Ser17 and Ser115) in the regulation of Cdc25A stability. We have shown that only S75A mutation abrogates Cdc25A degradation both in normal and stress conditions. We also studied the influence of stable form of Cdc25A on checkpoint progression after DNA damage. We have found out that delay in DNA synthesis after UV and IR does not depend on Cdc25A activity. However, the presence of stable Cdc25A increases the number of mitotic cells after these stresses.     

Mutagenic activity of antineoplastic agents under conditions of normal and artificial modification

Mutagenic effect of vincristine, vinblastine, thiophosphamide, sarcolysine and the supermutagen ethyleneimine was studied in Crepis capillaris germinating seeds at the G phase. Metabolic conditions, prolongation of cell cycle, specific activity of preparation as well as inhibition of DNA synthesis were found to modify the mutagenic process induced by antitumour agents.     

Hemodynamics (general and cerebral) and mental activity under normal conditions

Interrelations between the mental work efficiency and changes in total and cerebral hemodynamics during mental activity are considered. Five subgroups of the efficiency are distinguished. Changes in the vegetative reactions considerably differ in the type as well. Basic four types of such reactions are distinguished with allowance for changes in the character of minute blood circulation volume and cerebral blood flow. Comparison of changes in the efficiency of the activity with vegetative changes shows that in the process of the mental activity the vegetative changes are determined by interrelation between the intensity of the mental activity and its efficiency. It was concluded that the higher the activity efficiency, the lower the mental intensity and changes in the total and cerebral hemodynamics and, vice versa.     

Effect of the preparation baliz-2 on the integrative brain activity and biogenic amine metabolism in rats under stress

Effects of balis-2 on exploratory activity in the open field and elevated plus-maze, attention to sensory stimuli of different modalities, elaboration and retention of conditioned reflexes with food reinforcement, were studied in rats under stress. Prolonged treatment of rats with balis-2 seems to normalise integrative activity and metabolism of serotonine and dopamine in the animal brain.     

Calorimetric techniques for metabolic studies of cells and organisms under normal conditions and stress

When cells are subjected to stress, an early result is a shift in type and rate of metabolism to reflect their new conditions. The availability of metabolites, their endogenous vs exogenous origins, and the rates at which they can be used, besides availability of oxygen, dictate cell and tissue response. Measurement of heat output in such a response is a means for monitoring cells and tissues. Differential heat conduction calorimeters are reviewed to provide a listing of instrument parameters important in optimum practical use. Data obtained with one cell system, mammalian sperm, are presented to provide an example of how the combination of calorimetry and carbon balance, plus calculation from thermodynamic constants, permit an assessment of the importance of endogenous metabolism to total cellular metabolism.     

Uric acid inhibits liver phosphorylase a activity under simulated in vivo conditions

We have reported that glycogen synthesis and degradation can occur in vivo without a significant change in the amount of phosphorylase a present. These data suggest the presence of a regulatable mechanism for inhibiting phosphorylase a activity in vivo. Several effectors have been described. AMP stimulates, whereas ADP, ATP, and glucose inhibit activity. Of these effectors, only the glucose concentration changes under normal conditions; thus it could regulate phosphorylase a activity in vivo. We previously have reported that, when all of these effectors were present at physiological concentrations, the net effect was no change in phosphorylase a activity. Addition of caffeine, an independent inhibitor of activity, to the above effectors not only resulted in inhibition but also restored a glucose concentration-dependent inhibition. Because uric acid is an endogenous xanthine derivative, we decided to determine whether it had an effect on phosphorylase a activity. Independently, uric acid did not affect activity; however, when added at a presumed physiological concentration in combination with AMP, ADP, ATP, and glucose, it inhibited activity. A modest but not statistically significant glucose concentration-dependent inhibition was also present. Thus uric acid may play an important role in regulating phosphorylase a activity in vivo.     

Level of dehydrogenase activity in chipmunks under normal conditions and during chronic external gamma-irradiation

Chipmunks were chronically exposed to gamma-radiation at an average dose rate of 46 pA/kg. Changes in activity of succinate dehydrogenase (EC 1.3.99.1), pyruvate dehydrogenase (EC 1.2, 4.1) and lactate dehydrogenase (EC 1.1.1.27) were detected in the homogenates of the cardiac muscle, liver and brain at different physiological periods (before, during and after hibernation). The changes observed were related to the impairment of coordination between the processes of tissue respiration and glycolysis.