Activity of glutathione-dependent enzymes, catalase and superoxide dismutase in the liver and myocardium of rats with vitamin A deficiency

The alimentary deficiency of vitamin A causes marked shifts in the metabolism of GSH: the levels of GSH, GSSG and cysteine in the liver increase, while the activities of glutathione-S-transferase (using glycerol as substrate) and gamma-glutamyltransferase in the liver show a rise. At the same time, vitamin A deficiency causes a decrease of the glutathione peroxidase and catalase activity in the liver. The data obtained are discussed in terms of the role of GSH and enzymes of GSH metabolism in the protection of cells against the damaging influence of lipid peroxidation.     

A quantitative evaluation of the reactive and dystrophic changes in the cerebellar cortex of mice during malnutrition and subsequent food rehabilitation]

Neurones with chromatolysis, hyperchromatism and numerous nucleus have been counted of the paraffin cerebellar cortex sections coloured with kresil-violet and metil-green pironin. The alimentary deficiency has been shown to result in increase of cell number with chromatolysis and hyperchromatism and decrease of the number of numerous nucleus. The food rehabilitation doesn't take off completely damages caused by malnutrition. The use of carnitine leads to the complete rehabilitation that is due to the normalization of protein metabolism in cerebellum.     

ONTOGENETIC NICHE SHIFT IN THE BRACHIOPOD TEREBRATALIA TRANSVERSA: RELATIONSHIP BETWEEN THE LOSS OF ROTATION ABILITY AND ALLOMETRIC GROWTH

Abstract: Many articulated brachiopods experience marked life habit variations during ontogeny because they experience their fluid environment at successively higher Reynolds numbers, and they can change the configuration of their inhalant and exhalant flows as body size increases. We show that the extant brachiopod Terebratalia transversa undergoes a substantial ontogenetic change in reorientation governed by rotation around the pedicle. T. transversa′s reorientation angle (maximum ability to rotate on the pedicle) decreases during ontogeny, from 180 degrees in juveniles to 10–20 degrees in individuals exceeding 5 mm, to complete cessation of rotation in individuals larger than 10 mm. Rotation ability is substantially reduced after T. transversa achieves the adult lophophore configuration and preferred orientation with respect to ambient water currents at a length of 2.5–5 mm. We hypothesize that the rotation angle of T. transversa is determined mainly by the position of ventral and dorsal points of attachment of dorsal pedicle muscles relative to the pedicle. T. transversa shows a close correlation between the ontogenetic change in reorientation angle and ontogeny of morphological traits that are related to points of attachment of dorsal pedicle muscles, although other morphological features can also limit rotation in the adult stage. The major morphological change in cardinalia shape and the observed reduction of rotation affect individuals 2.5–10 mm in length. The position of ventral insertions of dorsal pedicle muscles remains constant, but contraction of dorsal pedicle muscles is functionally handicapped because dorsal insertions shift away from the valve midline, rise above the dorsal valve floor, and become limited by a wide cardinal process early in ontogeny (<5 mm). The rate of increase of cardinal process width and of distance between dorsal pedicle muscle scars substantially decreases in the subadult stage (5–10 mm), and most of the cardinalia shell traits grow nearly isometrically in the adult stage (>10 mm). T. transversa attains smaller shell length in crevices than on exposed substrates. The proportion of small‐sized individuals and population density is lower on exposed substrates than in crevices, indicating higher juvenile mortality on substrates prone to grazing and physical disturbance. The loss of reorientation ability can be a consequence of morphological changes that strengthen substrate attachment and maximize protection against biotic or physical disturbance (1) by minimizing torques around the pedicle axis and/or (2) by shifting energy investments into attachment strength at the expense of the cost involved in reorientation.     

Himasthla elongata: Effect of infection on expression of the LUSTR-like receptor mRNA in common periwinkle haemocytes

The first mollusc mRNA coding G-protein-coupled transmembrane receptor (GPСR), homologous to human receptors LUSTR 1 (GPR107) and LUSTR 2 (GPR108), was isolated from haemocytes of common periwinkle Littorina littorea. The analyses showed that the full-length cDNA is 1935 bp long and is predicted to encode a 614 amino acid protein (named Lit-LUSTR) with a calculated molecular mass of 69.6 kDa and theoretical isoelectric point 7.59. Pair-wise comparisons between Lit-LUSTR and LUSTR proteins from human or mouse have approximately 38% identity and 56% similarity. Lit-LUSTR clusters with LUSTR-A sub-family proteins and is a first characterization of proteins containing Lung7TM-R domain in Mollusca. Significant differences were found between the Lit-LUSTR mRNA levels in haemocytes of healthy periwinkles and those naturally infected with the echinostome trematode Himasthla elongata. Down regulated expression of the LUSTR-like receptor caused by infection illustrates modification of the haemocyte receptor system and may be attributed to the previously demonstrated greater numbers of “immature” haemocytes in the circulation of infected snails.     

Performance index as an indicator of the physiological state of trees in urban forest ecosystems

Based on the measurements of fluorescence of bark chloroplasts by means of PAM and PEA fluorometers, the information capacity of the methods for assessing the physiological state of Tilia cordata L. from the maximum quantum efficiency of PS II photochemistry (Fv/Fm) and the performance index (PI) has been compared. The measurements were performed on annual shoots of linden trees growing in different environment. It was shown that the chlorophyll content in the bark of shoots growing near the busy urban street was twice less compared with trees growing out of the city. On the trees from the unsafe environment, a small decrease in the relative fluorescence variable (Fv/Fm) was registered, and there was a significant statistical deviation of this value compared to control trees. It was found that the PI and its constituent parameters calculated on the basis of light fluorescence induction curve (PEA-method) are more informative and allow one to recognize changes in the primary energy transformation processes in PS II when they are comparatively small. The results of our work show that PI can be used as a sensitive and a rapid test to evaluate the physiological state of trees and other plant objects even under minor environmental changes.     

Lipid interacting regions in phosphate stress glycosyltransferase atDGD2 from Arabidopsis thaliana

Membrane lipid glycosyltransferases (GTs) in plants are enzymes that regulate the levels of the non-bilayer prone monogalactosyldiacylglycerol (GalDAG) and the bilayer-forming digalactosyldiacylglycerol (GalGalDAG). The relative amounts of these lipids affect membrane properties such as curvature and lateral stress. During phosphate shortage, phosphate is rescued by replacing phospholipids with GalGalDAG. The glycolsyltransferase enzyme in Arabidopsis thaliana responsible for this, atDGD2, senses the bilayer properties and interacts with the membrane in a monotopic manner. To understand the parameters that govern this interaction, we have identified several possible lipid-interacting sites in the protein and studied these by biophysical techniques. We have developed a multivariate discrimination algorithm that correctly predicts the regions in the protein that interact with lipids, and the interactions were confirmed by a variety of biophysical techniques. We show by bioinformatic methods and circular dichroism (CD), fluorescence, and NMR spectroscopic techniques that two regions are prone to interact with lipids in a surface-charge dependent way. Both of these regions contain Trp residues, but here charge appears to be the dominating feature governing the interaction. The sequence corresponding to residues 227-245 in the protein is seen to be able to adapt its structure according to the surface-charge density of a bilayer. All results indicate that this region interacts specifically with lipid molecules and that a second region in the protein, corresponding to residues 130-148, also interacts with the bilayer. On the basis of this, and sequence charge features in the immediate environment of S227-245, a response model for the interaction of atDGD2 with the membrane bilayer interface is proposed.