Biological effects of contaminated bottom sediments of water bodies in Central and South Vietnam on aquatic organisms

The levels of metal content and toxicity have been determined in bottom sediments of water bodies in Central and South Vietnam. It is found that the concentration of metals (As, Cr, Cu, Hg, Ni, Pb, and Zn) exceed the value of the abundance of elements in the Earth’s crust, which may be associated with geochemical features of the province. Acute toxicity of water-extracted sediment elutriate for Ceriodaphnia and whole (native) sediments for chironomid larvae is not recorded in any investigated water bodies. An increase in the relative abundance of Chironomus riparius larvae with deformations of mouthpart structures compared to the control was observed for most of the water bodies. This index reaches the value in the Khe River (Cân Th? city). Antenna anomalies prevailed in pathomorphological disorders.     

Toxicological and teratogenic assessment of bottom sediments from the Rybinsk Reservoir

The toxicity of bottom sediments (BSs) from different parts of the Rybinsk Reservoir has been determined by biotesting. Neither acute nor chronic toxicity are detected for ceriodaphnia Ceriodaphnia affinis Lillijeborg in tests with water extracts of sediments from all the investigated stations. The relative number of Chironomus riparius Meigen larvae with deformed mouth structures in the specimens exposed to the BSs of the reservoir is higher than in the control. Abnormalities of the mentum and mandibules (heavily chitinized structures) were the most often observed pathomorphological disturbances. The results of this study suggest that BSs from the stations located near the Cherepovets Industrial Complex (CIC) may be classified as contaminated.     

The effect of zinc oxide nano- and microparticles and zinc ions on freshwater organisms of different trophic levels

Data on the effects of various forms of zinc compounds on the biological parameters of freshwater animals (Ceriodaphnia affinis Lillijeborg, 1862; Chironomus riparius Meigen, 1804; and Brachydanio rerio Hamilton-Buchanan, 1822) are presented. Crustacean Ceriodaphnia affinis is the most sensitive test object studied.     

Peripheral circulation in the hand during natural ontogeny and under the conditions of prolonged graded traction

On the basis of the data of rheovasography (RVG) and laser Doppler flowmetry, comparative analysis of age-related changes in the peripheral blood circulation in hand tissues has been performed in 36 apparently healthy subjects aged 4–30 years and in 19 patients aged 18–50 years under the conditions of prolonged traction during surgical lengthening of finger bone stumps. The age-related changes in RVG are characterized by a higher volumetric blood content of tissues in children and adolescents, a decrease in the peripheral vascular tone, and wavelike recovery of capillary blood flow during reactive hyperemia, which is evidence for an unstable capillary tone. The dynamics of RVG indices during graded stretching in vivo (distraction) shows the dominance of an enhanced peripheral tone of arterioles and venules, and the response of the hand skin capillary bed to a 3-min ischemic test is analogous to the dynamics of indices of capillary blood flow in the hand skin of children.     

Backpropagating action potentials enable detection of extrasynaptic glutamate by NMDA receptors

Synaptic NMDA receptors (NMDARs) are crucial for neural coding and plasticity. However, little is known about the adaptive function of extrasynaptic NMDARs occurring mainly on dendritic shafts. Here, we find that in CA1 pyramidal neurons, back-propagating action potentials (bAPs) recruit shaft NMDARs exposed to ambient glutamate. In contrast, spine NMDARs are "protected," under baseline conditions, from such glutamate influences by peri-synaptic transporters: we detect bAP-evoked Ca(2+) entry through these receptors upon local synaptic or photolytic glutamate release. During theta-burst firing, NMDAR-dependent Ca(2+) entry either downregulates or upregulates an h-channel conductance (G(h)) of the cell depending on whether synaptic glutamate release is intact or blocked. Thus, the balance between activation of synaptic and extrasynaptic NMDARs can determine the sign of G(h) plasticity. G(h) plasticity in turn regulates dendritic input probed by local glutamate uncaging. These results uncover a metaplasticity mechanism potentially important for neural coding and memory formation.     

Freshwater sponge silicateins: Comparison of gene sequences and exon-intron structure

Silicateins found in spicules of siliceous sponges are proteins that take part in biogenic silica precipitation and determine the morphological features of spicules. The exon-intron structure of the genes encoding four silicatein-α isoforms (−α1, −α2, −α3, and −α4) from an endemic Baikalian sponge Lubomirskia baicalensis was studied. For eight sponge species, including both cosmopolitan (Spongilla lacustris, Ephydatia muelleri, E. fluviatilis) and endemic Baikalian (L. baicalensis, L. incrustans, Baikalospongia intermedia, B. fungiformis, Sw. papyracea) species, seventeen partial sequences of different silicatein isoform genes were determined. It was shown that cosmopolitan and endemic Baikalian sponges differ from each other in gene structure, in particular, in intron length. Among Baikalian sponges, silicatein-α1 genes had the highest variation of intron length, and silicatein-α4 genes were the most conservative. A phylogenetic analysis based on amino acid sequences of different silicatein isoforms identified four distinct clusters within the freshwater sponge clade. An analysis based on exon-intron gene sequences enables discrimination between different sponge species within the clusters.     

The Influence of the Superoxide Dismutase Preparation Rexod® on Survival of CFU–S in С57ВL/6 Mice Exposed to Irradiation

Biology Bulletin - The radioprotective efficiency of the Rexod® drug (State Research Institute of Highly Pure Biopreparations of the Federal Medical-Biological Agency of Russia) containing...     

The Effect of the Chronic Peripheral Circulatory Deficiency on Muscle Function in Lower Extremities

The muscle strength of the lower extremities was measured in 52 subjects between 30 to 48 years of age with chronic peripheral circulatory deficiency (grade endarteritis obliterans II–IV). The dynamometry was used to record the moments of strength of the flexor and extensor muscles of the crus and the dorsal and plantar flexors of foot. The transverse stiffness of the gastrocnemic muscles and the relationship between the strength of the crural muscles and the angle of talocrural articulation were investigated. The maximum moments of strength of the femoral and crural muscles in subjects with chronic peripheral circulatory deficiency were lower than those in the age-matched healthy subjects; as the pathological process increased, this difference became more significant. In subjects with endarteritis obliterans, the functions of the femoral and crural muscles decreased to the same extent.     

Modulation of ATP-induced LTP by cannabinoid receptors in rat hippocampus

Cannabinoids exert powerful action on various forms of synaptic plasticity. These retrograde messengers modulate GABA and glutamate release from presynaptic terminals by acting on presynaptic CB1 receptors. In particular, they inhibit long-term potentiation (LTP) elicited by electrical stimulation of excitatory pathways in rat hippocampus. Recently, LTP of the field excitatory postsynaptic potential (fEPSP) induced by exogenous ATP has been thoroughly explored. The present study demonstrates that cannabinoids inhibit ATP-induced LTP in hippocampal slices of rat. Administration of 10 μM of ATP led to strong inhibition of fEPSPs in CA1/CA3 hippocampal synapses. Within 40 min after ATP removal from bath solution, robust LTP was observed (fEPSP amplitude comprised 130.1 ± 3.8% of control, n = 10). This LTP never appeared when ATP was applied in addition to cannabinoid receptor agonist WIN55,212-2 (100 nM). Selective CB1 receptor antagonist, AM251 (500 nM), completely abolished this effect of WIN55,212-2. Our data indicate that like canonical LTP elicited by electrical stimulation, ATP-induced LTP is under control of CB1 receptors.

Electronic supplementary material

The online version of this article (doi:10.1007/s11302-012-9296-5) contains supplementary material, which is available to authorized users.