Age and growth of kaluga Acipenser dauricus from the estuary of the Amur and its lagoon

Age composition and the rate of growth of kaluga Acipenser dauricus from the estuary of the Amur and the Amur lagoon have been analyzed. Differences in the distribution of juvenile and mature individuals of kaluga in the river estuary and the lagoon were revealed. Males are dominant among mature individuals aged 18–26 years, and females are dominanat at an age 27–43 years. Females and males of the same age do not differ in length and body weight. A decrease in the rate of linear and gravimetric growth of mature individuals at the modern stage (2005–2008) compared to the period of 1965–1982 was revealed. Juvenile individuals of kaluga from the near-estuarine part of the Amur and its lagoon are inferior in the rate of growth to fish of the same age caught in the river channel, 500 km to the south.     

Early environment influences later performance in fishes

Conditions fish encounter during embryogenesis and early life history can leave lasting effects not only on morphology, but also on growth rate, life‐history and behavioural traits. The ecology of offspring can be affected by conditions experienced by their parents and mother in particular. This review summarizes such early impacts and their ecological influences for a variety of teleost species, but with special reference to salmonids. Growth and adult body size, sex ratio, egg size, lifespan and tendency to migrate can all be affected by early influences. Mechanisms behind such phenotypically plastic impacts are not well known, but epigenetic change appears to be one central mechanism. The thermal regime during development and incubation is particularly important, but also early food consumption and intraspecific density can all be responsible for later life‐history variation. For behavioural traits, early experiences with effects on brain, sensory development and cognition appear essential. This may also influence boldness and other social behaviours such as mate choice. At the end of the review, several issues and questions for future studies are given.     

Lowland river reference condition: spatial and temporal patterns of the zoobenthos community in the Volga headwaters (2006–2010)

The Volga, the largest river in Europe, has experienced multiple stressors from human activities. Recently we showed that its upper course (about 500 km, from its source to Tver) still has large sections with low impact and a natural type-specific potamal flora and fauna. Our present research in the East European lowlands aim to define reference conditions for mid-sized to large lowland rivers in order to build a basis for future management and conservation. Three monitoring sites were selected based on the results from intensive sampling in 2005. In subsequent field campaigns between 2006 and 2010 regular surveys were carried out each year in summer and additional ones in spring. A taxon-rich macroinvertebrate fauna, including several rare potamal relict species, was recorded and the data was used to provide an overview of annual and interannual variation in community indices and metrics. The conditions described for the headwaters of the Volga River system can be used as a reference state for medium-sized and large lowland rivers in regions where reference sites of these types are lacking.     

Selection analysis on the rapid evolution of a secondary sexual trait

Evolutionary analyses of population translocations (experimental or accidental) have been important in demonstrating speed of evolution because they subject organisms to abrupt environmental changes that create an episode of selection. However, the strength of selection in such studies is rarely measured, limiting our understanding of the evolutionary process. This contrasts with long-term, mark–recapture studies of unmanipulated populations that measure selection directly, yet rarely reveal evolutionary change. Here, we present a study of experimental evolution of male colour in Trinidadian guppies where we tracked both evolutionary change and individual-based measures of selection. Guppies were translocated from a predator-rich to a low-predation environment within the same stream system. We used a combination of common garden experiments and monthly sampling of individuals to measure the phenotypic and genetic divergence of male coloration between ancestral and derived fish. Results show rapid evolutionary increases in orange coloration in both populations (1 year or three generations), replicating the results of previous studies. Unlike previous studies, we linked this evolution to an individual-based analysis of selection. By quantifying individual reproductive success and survival, we show, for the first time, that males with more orange and black pigment have higher reproductive success, but males with more black pigment also have higher risk of mortality. The net effect of selection is thus an advantage of orange but not black coloration, as reflected in the evolutionary response. This highlights the importance of considering all components of fitness when understanding the evolution of sexually selected traits in the wild.     

Functional linear models for region-based association analysis

Regional association analysis is one of the most powerful tools for gene mapping because instead analysis of individual variants it simultaneously considers all variants in the region. Recent development of the models for regional association analysis involves functional data analysis approach. In the framework of this approach, genotypes of variants within region as well as their effects are described by continuous functions. Such approach allows us to use information about both linkage and linkage disequilibrium and reduce the influence of noise and/or observation errors. Here we define a functional linear mixed model to test association on independent and structured samples. We demonstrate how to test fixed and random effects of a set of genetic variants in the region on quantitative trait. Estimation of statistical properties of new methods shows that type I errors are in accordance with declared values and power is high especially for models with fixed effects of genotypes. We suppose that new functional regression linear models facilitate identification of rare genetic variants controlling complex human and animal traits. New methods are implemented in computer software FREGAT which is available for free download at http://mga.bionet.nsc.ru/soft/FREGAT/.     

Processing of lipid-modified prolipoprotein requires energy and sec gene products in vivo.

The kinetics of processing of glyceride-modified prolipoprotein that accumulated in globomycin-treated Escherichia coli has been found to be affected by sec mutations, i.e., secA, secE, secY, secD, and secF, and by metabolic poisons which affect proton motive force (PMF). The effect of sec mutations on processing of glyceride-modified prolipoprotein in vivo was not due to a secondary effect on PMF. Neither a secF mutation nor metabolic poisons affected the processing of previously accumulated proOmpA protein in vivo, suggesting that the requirements for functional sec gene products and PMF are specific to the processing of lipoprotein precursors by signal peptidase II.     

Chemical and microbiological solubilization of silicates

The solubilization of silicates was investigated using kaolin and quartz sand as model substances. The mineral solubilization was studied in the concentration of solubilized Si and Al. The chemical leaching of the silicates was carried out using inorganic and organic acids as well as sodium hydroxide. The process was more effective in the alkine than in the acid pH range. In the acid medium, oxalic acid showed maximum acidity and a tendency to form complex structures, especially with aluminium, and was most effective in leaching. The microbiological influence on solubilization reactions was tested using a number of microorganisms among them acid, alkali and slime-forming species. The highest leaching activity was observed in the case of Thiobacillus thiooxidans, whereas the heterotrophic microorganisms (among them Bacillus mucilaginosus) did not exercise a sollubilizing effect on the silicates. X-ray phase analysis of leached kaolin samples did not show any differences from the non-leached mineral.     

Evaluation of a trapping ELISA for the differentiation of foot-and-mouth disease virus strains using monoclonal antibodies.

A trapping enzyme-linked immunosorbent assay (ELISA) has been evaluated for the differentiation of foot-and-mouth disease virus (FMDV) strains using a panel of seven anti-serotype O monoclonal antibodies (MAbs). The variation of results within and between tests performed on the same day and on different days was examined using three strains of FMDV. Criteria for establishing antigenic differences between the strains as defined by the individual MAbs are proposed based on the variability measured, which can be used as standards by workers performing this test with other MAbs and FMDV strains.     

Immunogenesis and axoplasmic transport in Wistar rats]

Immunization of Wistar rats with thymus dependent antigens (sheep red blood cells-SRBC) is accompanied by a reliable increase in the synthesis of RNA and proteins in thalamic cerebral cortex and spinal marrow (48 hrs after antigen injection) and also in an increase in the intensity of rapid axoplasmic transport (RAT) along motor fibers of sciatic nerve (5,48,72 hrs following the beginning of immunization). There was a consecutive augmentation in AFC number in mesenteric and partly in inguinal lymph nodes (96 hrs after SRBC injection). Thus, time dependence between immunogenesis and axoplasmic transport in experimental animals (Wistar rats) was determined for the first time. It identifies another, previously unstudied, channel in interactions of immune and nervous systems.