Density, production and life cycle of Brachycentrus subnubilus Curtis (Trichoptera : Brachycentridae) in a lowland river, Central Poland

The annual mean density of Brachycentrus subnubilus a trichopteran species with a univoltine life-cycle was 572 ind. m(-2). It constituted of only 2.1% of the total macrozoobenthos abundance, while this species in terms of biomass exceeded 11.9% of the total benthic biomass. Production of Brachycentrus subnubilus was estimated by size-frequency method was 26.56 g wet weight m(-2) and the turnover ratio was 5.7

Factors shaping species richness and biodiversity of riverine macroinvertebrate assemblages at the local and regional scale

The biodiversity and species richness of benthic macroinvertebrate assemblages are under the strong pressure of environmental variables compounded with geographical and historical processes. Numerous studies that have investigated biodiversity and assemblage stability have shown the importance of choosing proper methodologies and paradigms. Consequently, the use of diversity measures and the partitioning of biodiversity at different spatial and temporal scales are of particular significance. Within habitats, only those species whose preferences remain within a tolerable range of the variability of abiotic factors are able to survive. The structure of biocoenosis at the local scale is determined mainly by current velocity/discharge, granulometry of the inorganic bottom substrate, quantity and quality of particulate organic matter, as well as water quality variables. Dispersion plays a key role in shaping regional diversity gradients, which supports the permanent inflow of individuals and their exchange between riverine basins. However, dispersion is also one of the basic aspects of the saturation/non-saturation of local communities with species from the regional species pool; a respective concept tries to determine how, why and to what degree local species richness is dependent on regional species richness

Compound-specific chlorine isotope fractionation in biodegradation of atrazine

Atrazine is a frequently detected groundwater contaminant. It can be microbially degraded by oxidative dealkylation or by hydrolytic dechlorination. Compound-specific isotope analysis is a powerful tool to assess its transformation. In previous work, carbon and nitrogen isotope effects were found to reflect these different transformation pathways. However, chlorine isotope fractionation could be a particularly sensitive indicator of natural transformation since chlorine isotope effects are fully represented in the molecular average while carbon and nitrogen isotope effects are diluted by non-reacting atoms. Therefore, this study explored chlorine isotope effects during atrazine hydrolysis with Arthrobacter aurescens TC1 and oxidative dealkylation with Rhodococcus sp. NI86/21. Dual element isotope slopes of chlorine vs. carbon isotope fractionation (ΛArthroCl/C = 1.7 ± 0.9 vs. ΛRhodoCl/C = 0.6 ± 0.1) and chlorine vs. nitrogen isotope fractionation (ΛArthroCl/N = −1.2 ± 0.7 vs. ΛRhodoCl/N = 0.4 ± 0.2) provided reliable indicators of different pathways. Observed chlorine isotope effects in oxidative dealkylation (εCl = −4.3 ± 1.8 ) were surprisingly large, whereas in hydrolysis (εCl = −1.4 ± 0.6 ) they were small, indicating that C-Cl bond cleavage was not the rate-determining step. This demonstrates the importance of constraining expected isotope effects of new elements before using the approach in the field. Overall, the triple element isotope information brought forward here enables a more reliable identification of atrazine sources and degradation pathways

Habitats and trophic relationships of Chironomidae insect larvae from the Sepotuba River basin, Pantanal of Mato Grosso, Brazil

Benthic habitats are linked by physical processes and are essential elements in assessing of the distribution dynamics of Chironomidae dipteran insects and their role in aquatic ecosystems. This work presents results of distribution patterns of chironomids larvae in 38 sites that are abundant in the study site, inhabiting the substrate of the main river channel, rapids, tributary brook, floodplain lakes and reservoir along the Sepotuba River from its mouth at the Paraguay River to the headwater region. A total of 1,247 larvae was registered. The most abundant taxa were Polypedilum (Tripodura) sp. (25.2%), Cricotopus sp.3 (23.0%) and Tanytarsus sp. (15.0%). Fissimentum desiccatum were found only in the reservoir; Fissimentum sp.2 and Tanytarsus cf. T. obiriciae sp.2 in floodplain lakes, and Goeldichironomus sp. in the main channel. The low diversity of the sites S06 and S35 is caused by the near-exclusive presence of the species Cricotopus sp.3, alone or together with one or another taxon (Tanytarsus sp., Djalmabatista sp.3). Collectors-filterers represent 16%, collectors-gatherers 15%, predators 11% and scrapers only 1%. The predators dominated in the secondary channel (±88 ind/m2), corresponding to 40% of the total of this group. Cryptochironomus sp.2 (34%) and Ablasbemyia gr. annulata (26%) were the most abundant among the predators. The differences along the river course are decisive for the formation of distinct or discontinuous communities and the limits become obvious though the interrelations between the populations in the community, as for instance, competition for food and habitats

INCREASED LEVELS OF INTERLEUKIN-10 EXPRESSION COMPARED TO INTERLEUKIN-6 IN LEUKOCYTES OF HEALTHY SUBJECTS. COULD IT BE USEFUL IN THE FUTURE OF THE DEPRESSION DIAGNOSIS?

It is a well known, that the physical activity promotes mental health. Physically active people relatively rarely suffer from psychosomatic and depressive disorders. It is possible that the differences in gene activity in peripheral blood leukocytes may be associated with depression, especially genes participating in inflammatory response. Thus, the aim of our study was to investigate the levels of IL6 and IL10 mRNA and IL10/IL6 ratio in peripheral blood leukocytes in healthy, physically active individuals. One hundred healthy young men (20-23 years old) participated in this study. All of them declared regular physical activity. Participants were non-smokers, and consumed alcohol occasionally. To access genes expression, 2 ml of venous blood was collected. RNA isolation was performed and then the relative expression of IL6 and IL10 was calculated using quantitative real-time polymerase chain reaction (Q-RT-PCR). Pro and anti-inflammatory balance was calculated as 2^relative of IL10/ 2^relative expression of IL6. Low expression of tested genes was found in healthy young men. Mean expression for IL6 was 2^0.051 (n=90) and for IL10 2^0.08 (n=98). Mean ratio IL10/IL6 was 2^1.58. Higher expression of IL10 compared to IL6 may be essential not only for the physical performance but also for the mental health. Diverse reports in the literature may be associated with choosing various control groups, i.e. sedentary or older individuals. It is possible, that measuring the expression of IL6 and IL10 (especially the ratio IL10/IL6) in peripheral blood leukocytes may be useful in the assessment of depressive disorders. Thus, molecular study of active young men can confirm the need for physical activity among people suffering from depression, but further studies are needed, particularly among people with psychosomatic disorders

Habitats and trophic relationships of Chironomidae insect larvae from the Sepotuba River basin, Pantanal of Mato Grosso, Brazil

Benthic habitats are linked by physical processes and are essential elements in assessing of the distribution dynamics of Chironomidae dipteran insects and their role in aquatic ecosystems. This work presents results of distribution patterns of chironomids larvae in 38 sites that are abundant in the study site, inhabiting the substrate of the main river channel, rapids, tributary brook, floodplain lakes and reservoir along the Sepotuba River from its mouth at the Paraguay River to the headwater region. A total of 1,247 larvae was registered. The most abundant taxa were Polypedilum (Tripodura) sp. (25.2%), Cricotopus sp.3 (23.0%) and Tanytarsus sp. (15.0%). Fissimentum desiccatum were found only in the reservoir; Fissimentum sp.2 and Tanytarsus cf. T. obiriciae sp.2 in floodplain lakes, and Goeldichironomus sp. in the main channel. The low diversity of the sites S06 and S35 is caused by the near-exclusive presence of the species Cricotopus sp.3, alone or together with one or another taxon (Tanytarsus sp., Djalmabatista sp.3). Collectors-filterers represent 16%, collectors-gatherers 15%, predators 11% and scrapers only 1%. The predators dominated in the secondary channel (±88 ind/m2), corresponding to 40% of the total of this group. Cryptochironomus sp.2 (34%) and Ablasbemyia gr. annulata (26%) were the most abundant among the predators. The differences along the river course are decisive for the formation of distinct or discontinuous communities and the limits become obvious though the interrelations between the populations in the community, as for instance, competition for food and habitats