Macrozoobenthos communities in the area of marine pipeline route at Piltun-Astokhskoye oil field (shelf of northeastern Sakhalin) and their long-term variability

Results of macrozoobenthos surveys (in total 86 stations, 432 sediment samples) in the area of marine pipeline route at Piltun-Astokhskoye oil field in July of 2007-2010 are presented. The sediment samples were collected by van Veen sampler (1-3 samples per site from the area 0.05 m2, 0.11 m2, or 0.25 m2) at the depth 0-45 m. The samples were washed by sea water through the sieve with mesh 1 mm, and the residues including macrobenthos were preserved by 4 % buffered formaldehyde for later processing with total identification of macrozoobenthos (species composition, abundance and biomass) in the laboratories of Far-Eastern Research Hydrometeorological Institute and Institute of Marine Biology in Vladivostok, following to standard techniques. The data were analysed using the PRIMER software including multidimensional cluster analysis of samples by hierarchical agglomerative method of group-average linking based on Bray-Curtis similarity of the macrozoobenthos species composition by biomass. In total, 272 species of macrozoobenthos are identified at the surveyed area, with the highest species number for amphipods (86 species) and polychaetes (72 species). Mean total abundance of macrozoobenthos is 26556.4 ± 2660.9 ind/m2, its mean total biomass is 669.7 ± 40.3 g/m2. Cumaceans and amphipod crustaceans are the most numerous groups; sea-urchins, bivalves and cumaceans have the highest biomass. Five benthic communities are defined by cluster analysis. There is concluded that the bottom sediments and depth are the main factors determining the characteristics and distribution patterns of benthic assemblages at present time

In vivo dynamics of acidosis and oxidative stress in the acute phase of an ischemic stroke in a rodent model

Ischemic cerebral stroke is one of the leading causes of death and disability in humans. However, molecular processes underlying the development of this pathology remain poorly understood. There are major gaps in our understanding of metabolic changes that occur in the brain tissue during the early stages of ischemia and reperfusion. In particular, it is generally accepted that both ischemia (I) and reperfusion (R) generate reactive oxygen species (ROS) that cause oxidative stress which is one of the main drivers of the pathology, although ROS generation during I/R was never demonstrated in vivo due to the lack of suitable methods. In the present study, we record for the first time the dynamics of intracellular pH and H2O2 during I/R in cultured neurons and during experimental stroke in rats using the latest generation of genetically encoded biosensors SypHer3s and HyPer7. We detect a buildup of powerful acidosis in the brain tissue that overlaps with the ischemic core from the first seconds of pathogenesis. At the same time, no significant H2O2 generation was found in the acute phase of ischemia/reperfusion. HyPer7 oxidation in the brain was detected only 24 h later. Comparison of in vivo experiments with studies on cultured neurons under I/R demonstrates that the dynamics of metabolic processes in these models significantly differ, suggesting that a cell culture is a poor predictor of metabolic events in vivo