Population structure of chum salmon Oncorhynchus keta in the Russian Far East, as revealed by microsatellite markers

Chum salmon populations in the Russian Far East have a complex multi-level genetic structure. A total of 53 samples (2446 fish) were grouped into five major regional clusters: the southern Kurils, eastern Sakhalin, southwestern Sakhalin, the Amur River, and a northern cluster. The northern cluster consists of chum salmon populations from a vast geographical region, including Chukotka, Kamchatka, and the continental coast of the Sea of Okhotsk. However, the degree of its genetic differentiation is low, 1.9%. In contrast, the southern population cluster exhibits much higher variation; for example, differentiation between chum salmon groups within Sakhalin Island reaches 4.6%, and the differentiation between Iturup Island and Sakhalin Island chum salmon is 7.7%. This suggests that southern populations of Asian chum salmon have a more ancient evolutionary history than northern populations. In contrast to the available data, our study indicates a great deviation of southwestern Sakhalin populations from other Sakhalin chum salmon. The Russian Far East chum salmon are genetically diverse and show statistically significant differentiation even within small geographic localities. This can be used to assign samples of unknown origins to definite local populations.     

Mechanism of estradiol-induced block of voltage-gated K+ currents in rat medial preoptic neurons

The present study was conducted to characterize possible rapid effects of 17-β-estradiol on voltage-gated K(+) channels in preoptic neurons and, in particular, to identify the mechanisms by which 17-β-estradiol affects the K(+) channels. Whole-cell currents from dissociated rat preoptic neurons were studied by perforated-patch recording. 17-β-Estradiol rapidly (within seconds) and reversibly reduced the K(+) currents, showing an EC(50) value of 9.7 μM. The effect was slightly voltage dependent, but independent of external Ca(2+), and not sensitive to an estrogen-receptor blocker. Although 17-α-estradiol also significantly reduced the K(+) currents, membrane-impermeant forms of estradiol did not reduce the K(+) currents and other estrogens, testosterone and cholesterol were considerably less effective. The reduction induced by estradiol was overlapping with that of the K(V)-2-channel blocker r-stromatoxin-1. The time course of K(+) current in 17-β-estradiol, with a time-dependent inhibition and a slight dependence on external K(+), suggested an open-channel block mechanism. The properties of block were predicted from a computational model where 17-β-estradiol binds to open K(+) channels. It was concluded that 17-β-estradiol rapidly reduces voltage-gated K(+) currents in a way consistent with an open-channel block mechanism. This suggests a new mechanism for steroid action on ion channels.     

Phase Diagrams for DNA Crystallization Systems

Abstract

Phase diagrams for several oligonucleotide duplex -spermine systems have been constructed. These diagrams characterize the duplex and spermine concentrations ranges in which crystalline precipitates are formed. All of them are wedge-like form. The slope of the upper branch of the diagram is determined by the oligonucleotide length. The position of the lower branch depends on both the nucleotide sequence and its length. The position of the lower branch depends on both the nucleotide sequence and its length. It has been shown that the addition to the system ofMgCl₂ and NaCl salts and MPD results in specific changes in the diagrams. A model for oligonucleotide duplex-spermine system has been suggested which explains the main characteristic features of the obtained phase diagrams. The experimental phase diagrams for the (pGpT)_n · (pApC)_n-spermine system (n = 2,3,4) have been analyzed ion terms of this model and the values of the binding constants of spermine and Mg²⁺ions binding to duplexes have been determined. It permitted to identify the complexes that precipitated in different regions of the phase diagrams under various conditions. The diagram obtained in the presence of a cobalt hexammine counterion is also considered. It has been shown that this phase diagram, in general, is similar to those obtained for the oligonucleotide duplex-spermine system.     

IL10 deficiency promotes alveolar enlargement and lymphoid dysmorphogenesis in the aged murine lung

The connection between aging‐related immune dysfunction and the lung manifestations of aging is poorly understood. A detailed characterization of the aging IL10‐deficient murine lung, a model of accelerated aging and frailty, reconciles features of both immunosenescence and lung aging in a coherent model. Airspace enlargement developed in the middle‐aged (12 months old) and aged (20–22 months old) IL10‐deficient lung punctuated by an expansion of macrophages and alveolar cell apoptosis. Compared to wild‐type (WT) controls, the IL10‐deficient lungs from young (4‐month‐old) mice showed increased oxidative stress which was enhanced in both genotypes by aging. Active caspase 3 staining was increased in the alveolar epithelial cells of aged WT and mutant lungs but was greater in the IL10‐deficient milieu. Lung macrophages were increased in the aged IL10‐deficient lungs with exuberant expression of MMP12. IL10 treatment of naïve and M2‐polarized bone marrow‐derived WT macrophages reduced MMP12 expression. Conditioned media studies demonstrated the secretome of aged mutant macrophages harbors reduced AECII prosurvival factors, specifically keratinocyte growth factor (KGF) and hepatocyte growth factor (HGF), promotes cell death, and reduces survival of primary alveolar epithelial cells. Compared to WT controls, aged IL10‐deficient mice have increased parenchymal lymphoid collections comprised of a reduced number of apoptotic cells and B cells. We establish that IL10 is a key modulator of airspace homeostasis and lymphoid morphogenesis in the aging lung enabling macrophage‐mediated alveolar epithelial cell survival and B‐cell survival within tertiary lymphoid structures.     

Global remodelling of cellular microenvironment due to loss of collagen VII

The mammalian cellular microenvironment is shaped by soluble factors and structural components, the extracellular matrix, providing physical support, regulating adhesion and signalling. A global, quantitative mass spectrometry strategy, combined with bioinformatics data processing, was developed to assess proteome differences in the microenvironment of primary human fibroblasts. We studied secreted proteins of fibroblasts from normal and pathologically altered skin and their post‐translational modifications. The influence of collagen VII, an important structural component, which is lost in genetic skin fragility, was used as model. Loss of collagen VII had a global impact on the cellular microenvironment and was associated with proteome alterations highly relevant for disease pathogenesis including decrease in basement membrane components, increase in dermal matrix proteins, TGF‐β and metalloproteases, but not higher protease activity. The definition of the proteome of fibroblast microenvironment and its plasticity in health and disease identified novel disease mechanisms and potential targets of intervention.     

Differentiation of chum salmon Oncorhynchus keta Walbaum populations as revealed with microsatellite and allozyme markers: a comparison

The character and extent of population differentiation in chum salmon Oncorhynchus keta from Sakhalin and Iturup were comparatively studied with 10 microsatellite and 12 allozyme markers. It was demonstrated with the example of allozyme polymorphism at the EstD locus that the effect of an individual locus with one major allele is capable of distorting the total picture of population differentiation. Multiallelic microsatellites were more efficient in revealing the genetic structure of chum salmon populations at the levels of differences between regional populations and between the stocks of individual rivers of the same region.     

Interregional differentiation of chum salmon from Sakhalin and South Kurils infered from microsatellite markers

Variability at ten microsatellite loci was examined in wild and hatchery populations of chum salmon from the Sakhalin Island and Southern Kuril Islands, Iturup and Kunashir. Substantial genetic differences between Sakhalin and South Kurils chum salmon (the differentiation theta reached 6.0%) were revealed. Statistically significant differences between chum salmon from Iturup and that from Kunashir were demonstrated, as well as between the chum salmon populations from different rivers within the islands. It was shown that in different types of population comparisons, required different marker sets most informative were.     

The dynamics of the activity parameters of the neuronal populations in the dorsal hyperstriatum of hens depending on the afferent input in ontogeny]

Studies have been made on the properties of neuronal populations of the dorsal hyperstriatum of the forebrain in hens beginning from the 18th day incubation up to the 7th day after hatching, which were incubated and kept either in darkness or under periodic illumination. Among the investigated parameters of multicellular activity, mean frequency of the discharge activity was found to be most susceptible to the level of external light afferentation in ontogenesis. The discharge activity was more intense in the left hemisphere of chick embryos and chicks from illuminated group, which may be associated with asymmetrical visual afferentation resulting from embryonic position within the egg, and its modulating effect on synchronization processes in the adjacent neurones of the given structure.     

Tendencies in auditory physiology

Main tendencies in studying of human and animals auditory system with psychoacoustical and electrophysiologycal methods are considered. Concerning psychoacoustical studies some basic data are presented as well as contemporary tendencies in hearing physiology in analysis of the intensity, frequency, temporal characteristics of the sound signals and data related to such phenomena as masking and adaptation. Data concerning directional hearing are presented in detail as a basis of auditory virtual reality. In electrophysiological studies of the auditory system detailed analysis of mapping in auditory centers and mechanisms concerning localization of unmoved and moving auditory stimuli was performed. Special attempt was paid to consider the reflection of different types of auditory signals in human evoked potentials.