Ultrastructural characteristics of the neocortex during rehabilitation from the sequelae of long-term protein-energy deficiency

Electron microscopy of mouse neocortex was carried out during rehabilitation following long-term protein-caloric deficiency. Food rehabilitation led to partial recovery of brain ultrastructure, however, a high neuronal level of secondary lysosoms and lipofuscin bodies was preserved, with the changes in the spine apparatus and synaptic contacts persisting in neuropile. Carnitine addition to food during rehabilitation increased the number of free ribosomes in cortical neurons. A substantial development of granular endoplasmic reticulum was observed. A greater number of spine apparatus cisterns was detected, however, like in conventional rehabilitation, the width of synaptic clefts and postsynaptic densities remained narrower than in control mice.     

immunocytochemical localization of urokinase-type plasminogen activator in lewis lung carcinoma

The invasively growing and metasizing Lewis lung carcinoma consistently contained urokinase-type plasminogen activator (u-PA) enzyme activity. When investigated immunocytochemically with antibodies against u-PA, different parts of individual tumors showed a pronounced heterogeneity in staining intensity. Strong staining was found in areas with invasive growth and degradation of surrounding normal tissue, while other areas were completely devoid of staining. Immunoreactivity occurred both with a perinuclear cytoplasmic localization in tumor cells and associated with apparently extracellular material. SDS PAGE of tumor extracts, under both reducing and nonreducing conditions, followed by immunoblotting, showed only one immunocytochemically stainable band with an electrophoretic mobility corresponding to that of purified proenzyme to u-PA, while no two-chain u-PA was detected. This indicates that the major part of the activator in Lewis lung carcinoma is present as one-chain pro-u-PA.     

Post-construction avian mortality monitoring at Project West Wind

Abstract

Post-construction avifauna investigations were undertaken at Project West Wind, Meridian Energy Limited's 62-turbine wind farm on the Wellington south coast. These investigations were required in accordance with the resource consent conditions to quantify the level of avian mortalities occurring at the wind farm, particularly in regard to New Zealand falcon (Falco novaeseelandiae), kākā (Nestor meridionalis) and kererū (Hemiphaga novaeseelandiae). This is the first comprehensive study at a New Zealand operating wind farm. The methods included three field components necessary to calculate annual estimates of mortalities across the wind farm site: routine turbine searches; carcass detection trials; and carcass removal trials. Results from years 1 and 2 of a three-year programme are presented. To date, mortalities have been recorded for 17 taxa at 18 of the 24 study turbines. There have been no recorded mortalities of falcon, kākā or kererū. Australasian harrier (Circus approximans) has been the species for which the most mortalities have been recorded. Overall estimated annual mortality rates for years 1 and 2 were calculated to be approximately six and five birds per turbine respectively.     

Genetic architecture of survival and fitness-related traits in two populations of Atlantic salmon

The additive genetic effects of traits can be used to predict evolutionary trajectories, such as responses to selection. Non-additive genetic and maternal environmental effects can also change evolutionary trajectories and influence phenotypes, but these effects have received less attention by researchers. We partitioned the phenotypic variance of survival and fitness-related traits into additive genetic, non-additive genetic and maternal environmental effects using a full-factorial breeding design within two allopatric populations of Atlantic salmon (Salmo salar). Maternal environmental effects were large at early life stages, but decreased during development, with non-additive genetic effects being most significant at later juvenile stages (alevin and fry). Non-additive genetic effects were also, on average, larger than additive genetic effects. The populations, generally, did not differ in the trait values or inferred genetic architecture of the traits. Any differences between the populations for trait values could be explained by maternal environmental effects. We discuss whether the similarities in architectures of these populations is the result of natural selection across a common juvenile environment.     

Mechanisms of Meiotic Restitution and Their Genetic Regulation in Wheat–Rye Polyhaploids

Meiosis has been studied in partially fertile wheat–rye F₁ hybrids yielded by crosses Triticum aestivum (Saratovskaya 29 variety) × Secale cereale L. (Onokhoiskaya variety) (4x =28). Hybrid self-fertility proved to be caused by formation of restituted nuclei, which appear after equational segregation of univalent chromosome in AI and sister chromatid non-separation in AII of meiosis, as well as after AI blockage in three different ways. Both types of meiotic restitution were found in each hybrid plant. Expression of the meiotic restitution trait varied significantly in polyhaploids of the same genotype (ears of the same plants, anthers of the same ear, microsporocytes of the same anther). Chromatin condensation in prophase proved to be related to the division type and univalent segregation in AI. During reduction segregation of univalents in AI, sister chromatid cohesion and chromosome supercondensation remained unchanged. The results obtained suggest that in the remote hybrids with haploid karyotype of the parental origin (polyhaploids), the program of two-stage meiosis may be fundamentally transformed to ensure one instead of two divisions. We propose that meiotic restitution is a result of special genetic regulation of the kinetochore organization (both structural and functional) and chromatin condensation, i.e. of major meiotic mechanisms.     

Porcine kidney extract contains a specific inhibitor of the ouabain-sensitive alpha2-isoform of Na, K-ATPase present in rat diaphragm fibres

In experiments on isolated rat diaphragm muscle, acetylcholine (100 nmol/l) hyperpolarized muscle fibres due to activation of the alpha 2 isoform of Na,K-ATPase. This hyperpolarization was blocked in a dose-dependent manner by ouabain (K0.5 = 8 +/- 4 nmol/l) as well as by a solution of porcine kidney extract (10 kDa cut-off filtration), with the K0.5 approximately equal to a 1:20,000-fold dilution. The inhibitory activity of the developed slowly over a period of 3 hours and, in contrast to ouabain, was still present after 1 hour of washing. Ouabain, but not the extract, inhibits Rb+ uptake in human erythrocytes that only express the alpha = 1 isoform of Na, K-ATPase. Our data suggest that in rat skeletal muscle the alpha 1 isoform of Na,K-ATPase is primarily responsible for ionic homeostasis, while the alpha 2 isoform provides a "regulatable" function and may be controlled by cholinergic stimulation and/or endogenous digitalis-like factors (EDLFs). Porcine kidney extract contains a factor (M. W. < 10 kDa) that selectively inhibits the rat alpha 2 isoform and differs from ouabain. Our experimental protocol can be used as a highly sensitive physiological assay for factors that selectively inhibit the alpha 2 isoform of Na,K-ATPase.     

Leptin activation of mTOR pathway in intestinal epithelial cell triggers lipid droplet formation,cytokine production and increased cell proliferation

Accumulating evidence suggests that obesity and enhanced inflammatory reactions are predisposing conditions for developing colon cancer. Obesity is associated with high levels of circulating leptin. Leptin is an adipocytokine that is secreted by adipose tissue and modulates immune response and inflammation. Lipid droplets (LD) are organelles involved in lipid metabolism and production of inflammatory mediators, and increased numbers of LD were observed in human colon cancer. Leptin induces the formation of LD in macrophages in a PI3K/mTOR pathway-dependent manner. Moreover, the mTOR is a serine/threonine kinase that plays a key role in cellular growth and is frequently altered in tumors. We therefore investigated the role of leptin in the modulation of mTOR pathway and regulation of lipid metabolism and inflammatory phenotype in intestinal epithelial cells (IEC-6 cells). We show that leptin promotes a dose- and time-dependent enhancement of LD formation. The biogenesis of LD was accompanied by enhanced CXCL1/CINC-1, CCL2/MCP-1 and TGF-β production and increased COX-2 expression in these cells. We demonstrated that leptin-induced increased phosphorylation of STAT3 and AKT and a dose and time-dependent mTORC activation with enhanced phosphorilation of the downstream protein P70S6K protein. Pre-treatment with rapamycin significantly inhibited leptin effects in LD formation, COX-2 and TGF-β production in IEC-6 cells. Moreover, leptin was able to stimulate the proliferation of epithelial cells on a mTOR-dependent manner. We conclude that leptin regulates lipid metabolism, cytokine production and proliferation of intestinal cells through a mechanism largely dependent on activation of the mTOR pathway, thus suggesting that leptin-induced mTOR activation may contribute to the obesity-related enhanced susceptibility to colon carcinoma.     

Zoobenthos communities and their seasonal dynamics in nonfreezing springs of Baikal region

The faunal composition, structure of the zoobenthos communities, and seasonal changes in two springs in the south of Irkutsk area are investigated. Both springs have the water temperature 4–5°C all year round. The fauna consists of widely distributed hydrobionts, crenobionts, stygobionts, and near-water organisms. Arctic relicts and elements of the Lake Baikal fauna are found. In macroinvertebrate communities, chironomid larvae dominate (by abundance and biomass), as do oligochaetes (by abundance). The lowest quantitative parameters are recorded in autumn-winter, and the highest parameters, in spring (March–April). Then they abruptly decline owing to emergence of amphibiotic insects. The structure of spring communities has regional specificity. By biomass of macrozoobenthos, the springs are comparable with mesotrophic and even eutrophic lakes.     

Effect of functional unloading and dystrophin deficit on the local hyperpolarization of the postsynaptic membrane of a skeletal muscle fiber

The data have been obtained that confirm the identity of the electrogenic mechanism of hyperpolarization by nanomolar concentrations of cholinergic ligands in the extrasynaptic region and endogenous nonquantal acetylcholine in the synaptic region of a skeletal muscle fiber. In both cases, this mechanism is realized through the involvement of the alpha2 isoform of Na, K-ATPase and operates in the absence of Na+ entry through membrane channels. At the same time, there are peculiar properties which take place under functional disorders. Thus, the effectiveness of this mechanism in the synaptic region selectively increases under rat hindlimb unloading and decreases in case of dystrophin deficit in mdx mice. The last fact suggests that dystrophin is a molecular component that is essential for the functioning of the electrogenic mechanism of local hyperpolarization of the end-plate membrane.