Consumption of aquatic subsidies by soil invertebrates in coastal ecosystems

Routes of aquatic allochthonous inputs (aquatic subsidies) to detrital food webs are studied, as is the effect of aquatic subsidies on the functional and taxonomic structure of soil invertebrate communities in coastal ecosystems. The study took place in the coastal zone of an oxbow lake of the Pra River in the Oka Reserve. The results indicate a strong dependence of soil animals in the coastal habitats on aquatic subsidies. Isotopic analysis shows that aquatic resources enter soil food webs not only via predators feeding on flying insects or aquatic prey, but also via saprophages decomposing organic debris of aquatic origin. The contribution of aquatic subsidies to the energy balance of soil invertebrates decreases rapidly with increasing distance from the lake. The fraction of aquatic carbon in tissues of collembolans and saprophages is negligible already a few meters from the water edge. The dependence of predatory invertebrates on aquatic resources can be traced at somewhat greater distance (tens of meters).     

A new role for PGRP-S (Tag7) in immune defense: lymphocyte migration is induced by a chemoattractant complex of Tag7 with Mts1

PGRP-S (Tag7) is an innate immunity protein involved in the antimicrobial defense systems, both in insects and in mammals. We have previously shown that Tag7 specifically interacts with several proteins, including Hsp70 and the calcium binding protein S100A4 (Mts1), providing a number of novel cellular functions. Here we show that Tag7–Mts1 complex causes chemotactic migration of lymphocytes, with NK cells being a preferred target. Cells of either innate immunity (neutrophils and monocytes) or acquired immunity (CD4⁺ and CD8⁺ lymphocytes) can produce this complex, which confirms the close connection between components of the 2 branches of immune response.     

Ultrastructural and functional changes in the myocardium and coronary vessels after massive blood loss

The ultrastructure of cardiomyocytes and circulatory bed has been compared to transmembrane cAMP-dependent Ca2+ transport in experiments on the hearts of 14 dogs immediately after massive blood loss. The results an hour after non-compensatory hemorrhage have shown extra- and intracellular myocardial edema, central destruction of sarcomers, steep increase in the volume of agranular sarcomplasmic reticulum and T-system, different degree of damage of other organoids, and also disturbances in the ultrastructure of venous capillary and postcapillary section. The biochemical techniques used have shown a decrease in Ca2+ transporting ability of sarcolemma due to its AMP-dependent regulation of cardiomyocytes. Excessive Ca2+ storage in cytosole promoted the appearance of "constriction bands" in myofibrils.     

The effect of Mg 2+ ions on the properties of various strains of Yersinia pestis

The strains of Yersinia pestis that restrict their growth on the media deficient for Mg2+ ions at 37 degrees C have been found. The bacterial cell lysis is registered under these conditions. The effect of Yersinia pestis own plasmids on the level of growth restriction in the absence of Mg2+ ions has been studied. The phenomenon is not connected with the presence of the plasmid determining Ca2(+)-dependence. The presence of 6Md plasmid coding for pesticinogenicity increased the frequency of colony formation, while the heavy plasmid determining the production of "mouse" toxin favoured the increase in growth restriction on Mg2(+)-less media. The clones growing under the latter conditions acquire the rearrangements in the DNA of the plasmid coding for the "mouse" toxin.     

Effects of ovariectomy on the composition of fatty acids of phospholipids in Java macaques with cholestasis

Bilateral ovariectomy carried out in Java macaques with simultaneous dosed ligation of common bile duct distally to duodenum in order to induce acalculous hepato-cholecystitis, does not alter the lithogenic index of the bile. Phospholipids present in enterohepatic organs and tissues (hepatocytes, enterocytes, chyme, blood and bile) of gonadectomized animals with hepato-cholecystitis acquire a specific fatty acid pattern which is characterized by prevailing palmitic, stearic and oleic acids, unaffected level of arachidonic acid and traces of essential linoleic acid.     

Effect of immobilization stress on the gonadotropic function of the hypophysis in male hamadryas baboons (Papio hamadryas)

The plasma levels of luteinizing hormone (LH) and testosterone were studied in intact and castrated male baboons exposed to 2- and 10-hour periods of immobilization. Presented data have shown that immobilization stress induced a marked decrease in LH concentration both in intact and castrated monkeys. Changes in LH concentration positively correlated with plasma levels of testosterone only during the experimental procedures. During three days after immobilization there was a sharp dissociation in the dynamics of testosterone levels remained low and LH returned to normal values. We can suggest that it is not absolute LH level that is responsible for the changes in testosterone secretion during the immobilization stress.     

Cytotoxic Effects of the Selective Ligands of Membrane Progesterone Receptors in Human Pancreatic Adenocarcinoma Cells BxPC3

Biochemistry (Moscow) - Progesterone and its synthetic analogues act on cells through different types of receptors, affecting proliferation and apoptosis. These compounds exert their effect through...     

Interaction of intracellular signalling and metabolic pathways at inhibition of mitochondrial aconitase by fluoroacetate

Mitochondrial aconitase has been shown to be inactivated under the effects of many compounds and critical states. Fluoroacetate (FA) is the best-known aconitase-inhibiting toxic agent. The biochemistry of the toxic action of FA has been rather well studied; however, no effective therapy has been developed over the past six decades. To search for new approaches to the development of possible antidotes, experiments were carried out in vitro with rat liver mitochondria, Ehrlich ascite tumor (EAT) cells, and cardiomyocytes exposed to FA or fluorocitrate (FC). FA produced its effects at much higher concentrations as compared with FC; in experiments with mitochondria these effects depended on respiratory substrates: with pyruvate, FA induced a slow oxidation and/or a leak of pyridine nucleotides and inhibition of respiration. Oxidation of pyridine nucleotides (PN) was prevented by the incubation of mitochondria with cyclosporin A. Studies of the PN level and dynamics of Ca²⁺ in EAT cells during activation by ATP also revealed the PN leak from mitochondria, which led to a shift in the balance of mitochondrial and cytosolic NAD(P)H under action of FA. Moreover, an increase of cytosolic Ca²⁺ was revealed in the cells exposed to FA, which could be explained by the activation of plasma membrane calcium channels. This mechanism could affect the amplitude and rate of calcium waves in cardiomyocytes under the effects of FA. We emphasize the reciprocal relationship between intracellular PN dynamics and calcium balance and discuss possible pathways of metabolic modulation in the context of development of effective therapy of poisoning with FA and other aconitase inhibitors.