Communities of hydrobionts and the physical-chemical characteristics of the estuary area of inflow of a flat water basin

The transitive and stable sites in the zone of changeable backup waters of inflow in the Ribinsk reservoir are determined on their physical-chemical parameters. The distribution of bacterioplankton and zooplankton and the density of the fish population are described. The similarities and distinctions of hydrobionts in the river, reservoir, and the zone of their water contact are shown. The zone of changeable backup waters (CBWs) is determined as ecotone according to its number of typical features.     

Antibodies and thermolabile opsonins in the phagocytosis of human red and white blood cells pretreated with formaldehyde

Erythrophagocytosis is conditioned by serum immunoglobulins. The extent of phagocytosis depends on the haematocrit of the red cell suspension pretreated with formaldehyde. The higher the haematocrit value, the lower will be the extent of phagocytosis. Phagocytosis of white blood cells pretreated with formaldehyde by granulocytes and monocytes is conditioned mainly by a thermolabile fraction of the serum, probably the complement.     

First evidence for active carnivorous predation in the European ground squirrel

acta ethologica - The Sciuridae family is generally referred to as herbivorous and occasionally omnivorous. Although sciurids are known to opportunistically feed on carcasses of other vertebrates...     

Thermodynamics of calmodulin and tubulin binding to the vinca-alkaloid vinorelbine

Vinca-alkaloids, such as vinblastine, and some of their derivatives, for example vinorelbine, are widely used in clinical therapy of leukemia and several types of tumors. Their effects are associated with the disfunctioning of the mitotic spindle, which leads to mitosis blockage and a shutting down of the cell cycle. Their primary target is tubulin; however, recent research has shown that some of the vinca-alkaloids inhibit calmodulin binding to its targets. Vinca-alkaloids binding with other proteins could be responsible for their efficiency and neuroprotection. Here, we investigated the thermodynamics of vinorelbine interactions with calmodulin and tubulin. It was determined that, unlike the other vinca-alkaloids, both vinorelbine binding sites are located in the C-domain of calmodulin and they are characterized by association constants of 4.0 × 10⁵ and 5.4 × 10⁴ M⁻¹. At the same time, the thermodynamics of vinorelbine binding to tubulin are not much different from that of other vinca-alkaloids. These results will allow us to get a better insight on the reaction mechanisms of vinca-alkaloids on a secondary protein target.     

Transmitter Sensitivity of Primary Afferent Cells of the Lamprey Lampetra fluviatilis Spinal Cord

Using dorsal sensory cells (primary afferents) of the spinal cord of the lamprey Lampetra fluviatilis, isolated by an enzymatic-mechanical method, their responses have been studied to application of excitatory amino acids (EAA), glutamate, aspartate, kainate, N-methyl-D-aspartate (NMDA), and of inhibitory amino acids, GABA and glycine, as well as of neuromodulator serotonin (5-hydroxytryptamine, 5-HT). The patch-clamp method was applied to fix either potential or current through membranes of studied cells. It was shown that of all the above substances, only NMDA and kainate could produce in dorsal cells depolarization, input current with maximal amplitude up to 16 nA, and action potential. The main attention in this work was paid to NMDA-current properties. The dose–effect curves were obtained; a blocking effect of specific antagonist of NMDA-receptors, 2-amino-5-phosphonovalerian acid (APV), was shown; passage of Ba ions through Ca²⁺-channels of dorsal sensory cell membranes at NMDA application was proven. It has been established that in a half of the studied cells under effect of NMDA there is an increase of the maximal amplitude of the potential-activated current through Ca²⁺-channels, on average, by 22.5 ± 10.5% (n = 21). It was suggested that this variation might be essential for an increase of amount of the transmitter released in synapses formed by processes dorsal sensory cells, while NMDA could be considered a modulator facilitating synaptic activity of these cells.     

Stress-induced changes in accumulation of sorbitol and in activities of concomitant enzymes in digestive gland of freshwater snail

Sorbitol content was determined in the digestive gland of freshwater snail (Viviparus viviparus L.) in different seasons and in a short-term experiment on the water temperature decrease and on intoxication with cadmium chloride. In the model experiments, changes in activities of enzymes involved in sorbitol metabolism (acid phosphatases, sorbitol dehydrogenase, and aldose reductase) were also studied. Sorbitol was accumulated by the snail in response to the temperature decrease (as a cryoprotectant) and under conditions of acute intoxication (as a probable metabolic regulator or a nonspecific protective factor). However, the mechanisms of this accumulation are different: on cold adaptation sorbitol is produced as a result of reduction of glucose under the influence of aldose reductase, and on intoxication sorbitol is mainly produced from fructose under the influence of sorbitol dehydrogenase. Pathways of the sorbitol accumulation and its re-involvement into metabolism are not always the same, and this might be a mechanism for regulation of carbohydrate metabolism (at the initial stage of glycolysis) on adaptation to unfavorable factors of the environment.     

Orthologs of the Arabidopsis CLAVATA1 Gene in the Cultivated Brassicaceae Plants

In Arabidopsis thaliana, the CLAVATA1 (CLV1) gene is involved in maintaining the balance between the stem cells in the central zone of the stem apical meristem and the determined cells at its periphery. However, CLV1 has not been previously characterized in other Brassicaceae. Using the direct amplification of genomic DNA, we obtained a full-length CLV1 ortholog from canola plants (Brassica napus), and also three CLV1 fragments from rape (B. rapa), canola (B. napus), and false flax (Camelina sativa), which corresponded to the transmembrane domain and a part of the kinase domain of the CLAVATA1 protein. The nucleotide and deduced amino acid sequences of the full-size CLV1 ortholog from B. napus were similar by 81 and 87% to the prototype gene from arabidopsis; in the case of shorter gene fragments, the similarity was as high as 91–93 and 98%, respectively. By their primary structure, the CLV1 genes in the Brassicaceae considerably differ from their putative structural homologs beyond this family.     

Preservation of integrity of the inner mitochondrial membrane after freeze-thawing and freeze-drying

The results of this paper illustrate that trehalose partially preserves inner mitochondrial membrane integrity after freeze-thawing and freeze-drying with subsequent rehydration in water. The 2,4-dinitrophenol stimulation of ATPase activity was used as a criterion for membrane integrity. The results show that ATPase activity of lyophilized-rehydrated mitochondria was stimulated up to two to three times.