Phytoindicational properties of the vegetation in landscape transformation studies on Sibay chalcopyrite deposits (Southern Urals)

Changes in biogeochemical, morphological, floristic, and phytocenotic vegetation properties around Sibay chalcopyrite deposits at different distances from mining facilities have been studied. Heavy metal (HM) (Cu, Zn, Fe, Pb, Cd, Ni, Co, Cr, and Mn) content has been measured in samples of soils, waters, bottom sediments, total aboveground phytomass, and several plant species (Artemisia austriaca, Salvia stepposa, Thymus marschallianus, Veronica incana, Caragana frutex, Phlomis tuberosa, Achilea setacea, Galium verum, and Phragmites australis). Groups (pleiadas) of species have been identified based on interspecific contingency coefficient. These pleiadas correspond to ecological conditions and level of anthropogenic stress of the habitats. The set of features for evaluating natural territorial transformations of complexes by means of phytoindication is proposed.     

Effect of cultivation temperature on nucleic acid level in bacteria Listeria monocytogenes and Yersinia pseudotuberculosis

The relationship between the multiplication of bacteria, the content of nucleic acid and the specific rate of their growth during their batch cultivation in nutrient broth and mineral medium at temperatures of 37 degrees C and 4-6 degrees C was studied in the causative agents of saprozoonotic infections with L. monocytogenes and Y. pseudotuberculosis used as typical representatives of such bacteria. The content of DNA was shown to remain practically unchanged after the alteration of cultivation temperature and the conditions of nutrition. The linear relationship between the content of RNA and specific growth rate was registered both at 37 degrees C and 4-6 degrees C. However a higher content of RNA at low temperatures was found to correspond to one and the same specific growth rate, which was linked with the additional synthesis of this nucleic acid.     

The biochemical mechanisms of energy support in Yersinia pseudotuberculosis cells at a low cultivation temperature

The object of the study was the first stage of biological oxidation: the transfer of hydrogen electrons to the components of the respiratory chain of Y. pseudotuberculosis cells by NAD and NADF, coenzymes of pyridine-dependent dehydrogenases, having labile redox properties. The study revealed that in the low-temperature cultivation of Y. pseudotuberculosis an increase in the content of NAD and NADF was 1.5- to 2.0-fold greater than that observed at 37 degrees C, which was indicative of the fact that at low environmental temperature pyridine-dependent dehydrogenases played a more important role than at high temperature (37 degrees C). This, in combination with other mechanisms, made it possible for bacterial cells to maintain the level of energy metabolism, necessary for their survival, in the environment with low and constantly changing temperature.     

Respiratory activity of isolated rat hepatocytes following cold storage and subsequent rewarming: a comparison of sucrose-based and University of Wisconsin solutions

Investigations were carried out on the respiratory function of isolated rat hepatocytes after cold storage alone for periods up to 48 h in either sucrose-based solution (SBS) or University of Wisconsin (UW) solution and after subsequent normothermic preincubation. In both SBS and UW, cold storage for 24 h depressed respiratory function (to 21 +/- 3 and 23 +/- 3 nmol O(2)/min/10(6) cells, respectively) compared to control cell values (31 +/- 3 and 33 +/- 5 nmol O(2)/min/10(6) cells; P < 0.01 in each case). However, normothermic preincubation for 60 min returned respiratory activity to control values (for SBS and UW storage: 41 +/- 6 and 40 +/- 5 nmol O(2)/min/10(6) cells; for control cells: 43 +/- 5 and 46 +/- 6 nmol O(2)/min/10(6) cells). Storage for 48 h in both SBS and UW allowed further depression of respiratory activity, with no recovery after preincubation. Stimulation of respiration by succinate in hepatocytes stored for longer periods was suggestive of increased membrane permeability. Both SBS and UW are effective storage solutions for isolated hepatocytes for up to 24 h as judged by aerobic metabolism, but significant damage was expressed in both solutions when preservation was extended.     

Cytokinin oxidase is key enzyme of cytokinin degradation

Cytokinin oxidase (EC 1.5.99.12) is an enzyme that catalyzes the irreversible degradation of cytokinin phytohormones that are extremely necessary for growth, development, and differentiation of plants. Cytokinin oxidase plays an important role in the regulation of quantitative level of cytokinins and their distribution in plant tissues. This review generalizes the available information on the structure, properties, and functional role of this enzyme in plant ontogeny under conditions of normal growth and under the influence of unfavorable environmental factors.     

The miR‐379/miR‐410 cluster at the imprinted Dlk1‐Dio3 domain controls neonatal metabolic adaptation

In mammals, birth entails complex metabolic adjustments essential for neonatal survival. Using a mouse knockout model, we identify crucial biological roles for the miR‐379/miR‐410 cluster within the imprinted Dlk1‐Dio3 region during this metabolic transition. The miR‐379/miR‐410 locus, also named C14MC in humans, is the largest known placental mammal‐specific miRNA cluster, whose 39 miRNA genes are expressed only from the maternal allele. We found that heterozygote pups with a maternal—but not paternal—deletion of the miRNA cluster display partially penetrant neonatal lethality with defects in the maintenance of energy homeostasis. This maladaptive metabolic response is caused, at least in part, by profound changes in the activation of the neonatal hepatic gene expression program, pointing to as yet unidentified regulatory pathways that govern this crucial metabolic transition in the newborn's liver. Not only does our study highlight the physiological importance of miRNA genes that recently evolved in placental mammal lineages but it also unveils additional layers of RNA‐mediated gene regulation at the Dlk1‐Dio3 domain that impose parent‐of‐origin effects on metabolic control at birth and have likely contributed to mammal evolution.     

Reversible mitochondrial uncoupling in the cold phase during liver preservation/reperfusion reduces oxidative injury in the rat model

Reversible uncoupling of the mitochondrial electron-transport chain may be one strategy to prevent intracellular oxidative stress during liver cold preservation/warm reperfusion (CP/WR) injury. 2,4-Dinitrophenol (DNP) is a potent water-soluble uncoupling agent for supplementation of the hepatic CP solution. The aim of this work was to investigate the possible influence of DNP in the CP solution on the isolated rat liver state during CP/WR. Livers were subjected to CP at 4 °C in sucrose–phosphate based solution (SPS) for 18 h, followed by WR for 60 min in vitro. The final concentration of DNP was 100 μM. DNP presence during the CP stage led to partial ATP level decrease accompanied by a significant diminution in liver TBARS and a prevention of antioxidant enzyme activity decrease (catalase, GSH-PO, GSH-Red) when compared with livers stored without DNP. After DNP wash-out during WR, an improvement in the mitochondrial functional state (higher respiratory control indices and ATP levels, and a decrease in V₄ respiration rates) were observed. This was concurrent with lower TBARS levels, higher antioxidant enzyme activities and significant increase of bile production. The results suggest that reversible uncoupling may be one way to influence oxidative stress associated with hepatic cold preservation.