Unusual isozyme patterns of glucose-6-phosphate isomerase in polydorids (Polychaeta: Spionidae) and the possible mechanisms of their formation

The isozyme patterns of glucose-6-phosphate isomerase (GPI) have been analyzed in ten species of polychaetes of the genera Polydora and Dipolydora (Polychaeta: Spionidae). The GPI patterns of these species have been found to have some specific characteristics that cannot be explained in terms of the generally accepted views on the nature of isozymes. The patterns are represented by two hybridizing isozymes with different expression specificities that exhibit coordinated allozymic variation in most individuals of each species studied. Involvement of alternative splicing in the expression of the GPI gene is considered to be the most probable mechanism of the formation of the unusual GPI isozyme patterns in polydorids.     

Microchromatographic study of proteins in hippocampal field CA3 during prolonged posttetanic potentiation in surviving sections

A study was made of 3H-leucine incorporation into water- and tween-soluble proteins of the hippocampal CA3 field under the development of prolonged post-tetanic potentiation (PPTP) because of stimulation of mossy fibers. The mixture of supernatant proteins was assayed by ion-exchange microchromatography while each fraction was evaluated for the radioactive label incorporation. In the course of the assay of the chromatograms obtained, no significant alterations in the protein spectrum were found during the development of the PPTP. Substantial changes were identified in the rate of the labeled leucine incorporation in the acid part of the spectrum represented by acid proteins and polypeptides including brain specific ones. It is assumed that the development of the PPTP in the hippocampal pyramids is associated with activation of the proteins under consideration.     

Changes in the behavior and EEG of rats administered penicillin and a physiological solution into the amygdalar basal nuclei]

Three weeks after implantation of the electrodes for EEG recording, hyperactivation of the basal nucleus of rat's amygdala was produced by a local injection of penicillin (0.5 mcl, 1% solution). Saline injection of the same volume served as control. The hyperactivation of the amygdala resulted in a long-lasting (at least for 3 weeks) increase in the locomotor activity against the background and deficit in exploratory behavior and rise of the level of anxiety and fear. The behavioral changes were accompanied by a long-term disruption of the hippocampal theta rhythm, appearance and slowing of the immobility-related high-voltage spindles, and increase in the EEG dominant frequency in the state of emotional tension. Saline injection led to a short-time (up to 1 week) decrease in locomotor and exploratory activity and increase in anxiety. These phenomena were accompanied by a short-time disruption of the theta rhythm and appearance of the 10-13-Hz oscillations characteristic for the state of emotional tension.     

Studies of the Processes of the Trypsin Interactions with Ion Exchange Fibers and Chitosan

Russian Journal of Bioorganic Chemistry - A localization of charged and hydrophobic amino acid residues in the trypsin molecule was studied, and a percentage of the amino acids of different types...     

Intact endothelial autophagy is required to maintain vascular lipid homeostasis

The physiological role of autophagic flux within the vascular endothelial layer remains poorly understood. Here, we show that in primary endothelial cells, oxidized and native LDL stimulates autophagosome formation. Moreover, by both confocal and electron microscopy, excess native or modified LDL appears to be engulfed within autophagic structures. Transient knockdown of the essential autophagy gene ATG7 resulted in higher levels of intracellular ¹²⁵I‐LDL and oxidized LDL (OxLDL) accumulation, suggesting that in endothelial cells, autophagy may represent an important mechanism to regulate excess, exogenous lipids. The physiological importance of these observations was assessed using mice containing a conditional deletion of ATG7 within the endothelium. Following acute intravenous infusion of fluorescently labeled OxLDL, mice lacking endothelial expression of ATG7 demonstrated prolonged retention of OxLDL within the retinal pigment epithelium (RPE) and choroidal endothelium of the eye. In a chronic model of lipid excess, we analyzed atherosclerotic burden in ApoE^?/?mice with or without endothelial autophagic flux. The absence of endothelial autophagy markedly increased atherosclerotic burden. Thus, in both an acute and chronic in vivo model, endothelial autophagy appears critically important in limiting lipid accumulation within the vessel wall. As such, strategies that stimulate autophagy, or prevent the age‐dependent decline in autophagic flux, might be particularly beneficial in treating atherosclerotic vascular disease.     

Fish growth hormone genes: Divergence of intron sequence in charrs of Salvelinus genus

Sequences of the two large introns (C and D) from two paralogous growth hormone genes, GH1 and GH2, were compared in eight charr species of the Salvelinus genus (Osteichthes, Salmonidae). It was demonstrated that the rates of intron divergence in these two genes were remarkably different. Introns in the GH1 gene appeared to be more conservative, while the rate of intron variations was considerably higher in the GH2 gene. These data suggest that noncoding regions of nuclear genes under the selective pressure. The lower congruence of phylogenetic scheme constructed based on an analysis of the GH1 introns compared to that based on the GH2 data, as well as with the traditional views on the evolution of charr species, also favors the supposition on differences in the forces and directions of the selective pressure on the introns.     

Circadian rhythms in zebrafish (Danio rerio) behaviour and the sources of their variability

Over recent decades, changes in zebrafish (Danio rerio) behaviour have become popular quantitative indicators in biomedical studies. The circadian rhythms of behavioural processes in zebrafish are known to enable effective utilization of energy and resources, therefore attracting interest in zebrafish as a research model. This review covers a variety of circadian behaviours in this species, including diurnal rhythms of spawning, feeding, locomotor activity, shoaling, light/dark preference, and vertical position preference. Changes in circadian activity during zebrafish ontogeny are reviewed, including ageing-related alterations and chemically induced variations in rhythmicity patterns. Both exogenous and endogenous sources of inter-individual variability in zebrafish circadian behaviour are detailed. Additionally, we focus on different environmental factors with the potential to entrain circadian processes in zebrafish. This review describes two principal ways whereby diurnal behavioural rhythms can be entrained: (i) modulation of organismal physiological state, which can have masking or enhancing effects on behavioural endpoints related to endogenous circadian rhythms, and (ii) modulation of period and amplitude of the endogenous circadian rhythm due to competitive relationships between the primary and secondary zeitgebers. In addition, different peripheral oscillators in zebrafish can be entrained by diverse zeitgebers. This complicated orchestra of divergent influences may cause variability in zebrafish circadian behaviours, which should be given attention when planning behavioural studies.