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.     

Study on the role of SH-groups in the activity of muscle pyruvate dehydrogenase

The kinetics of inactivation of the pyruvate dehydrogenase component of the pigeon breast muscle pyruvate dehydrogenase complex in the presence of 5,5'-dithiobis (2-nitrobenzoate) is biphasic. The rate constants for the fast and slow phases of the inactivation reaction are close to those for modification of two classes of SH-groups differing in their reactivities towards the inhibitor. The reaction order with respect to the inhibitor concentration suggests that the two distinct SH-groups are essential for the enzyme activity. Modification of these SH-groups results in inhibition of the overall activity of the pyruvate dehydrogenase complex and of the 2-hydroxyethyl thiamine pyrophosphate - acceptor oxidoreductase activity of its decarboxylating component. Thiamine pyrophosphate exerts a protective effect on the enzyme only at the slow phase of the enzyme inactivation and SH-modification. As a result of interaction between the holoenzyme and pyruvate (or apoenzyme and 2-hydroxyethyl thiamine pyrophosphate) the rate of the enzyme inactivation is increased. This is associated with masking of non-essential SH-groups and with an increase of the accessibility of two essential SH-groups to the inhibitor. The data obtained suggest the interrelationship between the essential SH-groups and the 2-hydroxyethyl thiamine pyrophosphate-acceptor oxidoreductase activity of pyruvate dehydrogenase.     

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.     

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.     

Selected anthropometric variables and aerobic fitness as predictors of cardiovascular disease risk in children

The aim of this study was to assess the suitability of body mass index, waist circumference, waist-to-height ratio and aerobic fitness as predictors of cardiovascular risk factor clustering in children. A cross-sectional study was conducted with 290 school boys and girls from 6 to 10 years old, randomly selected. Blood was collected after a 12-hour fasting period. Blood pressure, waist circumference (WC), height and weight were evaluated according to international standards. Aerobic fitness (AF) was assessed by the 20-metre shuttle-run test. Clustering was considered when three of these factors were present: high systolic or diastolic blood pressure, high low-density lipoprotein (LDL) cholesterol, high triglycerides, high plasma glucose, high insulin concentrations and low high-density lipoprotein (HDL) cholesterol. A ROC curve identified the cut-off points of body mass index (BMI), WC, waist-to-height ratio (WHtR) and AF as predictors of risk factor clustering. BMI, WC and WHR resulted in significant areas under the ROC curves, which was not observed for AF. The anthropometric variables were good predictors of cardiovascular risk factor clustering in both sexes, whereas aerobic fitness should not be used to identify cardiovascular risk factor clustering in these children.     

Functional Identification of H<Superscript>+</Superscript>-ATPase and Na<Superscript>+</Superscript>/H<Superscript>+</Superscript> Antiporter in the Plasma Membrane Isolated from the Root Cells of Salt-Accumulating Halophyte <Emphasis Type="Italic">Suaeda altissima</Emphasis>

A membrane fraction enriched in plasma membrane (PM) vesicles was isolated from the root cells of a salt-accumulating halophyte Suaeda altissima (L.) Pall. by means of centrifugation in discontinuous sucrose density gradient. The PM vesicles were capable of generating ΔpH at their membrane and the transmembrane electric potential difference (Δψ). These quantities were measured with optical probes, acridine orange and oxonol VI, sensitive to ΔpH and Δψ, respectively. The ATP-dependent generation of ΔpH was sensitive to vanadate, an inhibitor of P-type ATPases. The results contain evidence for the functioning of H⁺-ATPase in the PM of the root cells of S. altissima. The addition of Na⁺ and Li⁺ ions to the outer medium resulted in dissipation of ΔpH preformed by the H⁺-ATPase, which indicates the presence in PM of the functionally active Na⁺/H⁺ antiporter. The results are discussed with regard to involvement of the Na⁺/H⁺ antiporter and the PM H⁺-ATPase in loading Na⁺ ions into the xylem of S. altissima roots.     

Involvement of Long-Distance Na<Superscript>+</Superscript> Transport in Maintaining Water Potential Gradient in the Medium-Root-Leaf System of a Halophyte <Emphasis Type="Italic">Suaeda altissima</Emphasis>

The aim of this study was to determine the range of NaCl concentrations in the nutrient solution that allow Suaeda altissima (L.) Pall., a salt-accumulating halophyte, to maintain the upward gradient of water potential in the “medium-root-leaf” system. We evaluated the contribution of Na⁺ ions in the formation of water potential gradient and demonstrated that Na⁺ loading into the xylem is involved in this process. Plants were grown in water culture at NaCl concentrations ranging from zero to 1 M. The water potential of leaf and root cells was measured with the method of isopiestic thermocouple psychrometry. When NaCl concentration in the growth medium was raised in the range of 0–500 mM (the medium water potential was lowered accordingly), the root and leaf cells of S. altissima decreased their water potential, thus promoting the maintenance of the upward water potential gradient in the medium-root-leaf system. Growing S. altissima at NaCl concentrations f 750 mM and 1 M disordered water homeostasis and abolished the upward gradient of water potential between roots and leaves. At NaCl concentrations of 0–250 mM, the detached roots of S. altissima were capable of producing the xylem exudate. The concentration of Na⁺ in the exudate was 1.3 to 1.6 times higher than in the nutrient medium; the exudate pH was acidic and was lowered from 5.5 to 4.5 with the rise in the salt concentration. The results indicate that the long-distance Na⁺ transport and, especially, the mechanism of Na⁺ loading into the xylem play a substantial role in the formation of water potential gradient in S. altissima. The accumulation of Na⁺ in the xylem and acidic pH values of the xylem sap suggest that Na⁺ loading into the xylem is carried out by the Na⁺/H⁺ antiporter of the plasma membrane in parenchymal cells of the root stele.__________Translated from Fiziologiya Rastenii, Vol. 52, No. 4, 2005, pp. 549–557.Original Russian Text Copyright © 2005 by Balnokin, Kotov, Myasoedov, Khailova, Kurkova, Lun’kov, Kotova.     

Conversion of quaternary ammonium compounds in the whole plant system of the halophyte Suaeda altissima

The total content of quaternary ammonium compounds (QAC) and the choline content in roots, leaves, and xylem exudates of the halophyte Suaeda altissima (L.) Pall. were determined after growing plants at various NaCl concentrations in the nutrient solution (1, 50, 100, and 250 mM). Based on the results obtained, the content of glycine betaine in organs and xylem exudates of S. altissima was estimated as the difference between the total content of QAC and the choline content. In roots choline accounted for the largest portion of QAC (from 69 to 96% at various NaCl concentrations in nutrient media), whereas in leaves it contributed only 12–23%. The contribution of choline to QAC content in the xylem exudates was 84–90%. It is concluded that choline in S. altissima is mainly synthesized in roots and is delivered with the ascending water flow to leaves where it is utilized as a substrate for glycine betaine synthesis. The content of glycine betaine in leaves increased with elevation of NaCl concentration in the nutrient solution, thus contributing appreciably to the maintenance of osmotic balance in the cytoplasm of S. altissima at high salinity.     

Substrate-dependent inactivation of muscle pyruvate dehydrogenase: identification of the acetyl-substituted enzyme form

The properties of the pyruvate dehydrogenase component isolated from the pigeon breast muscle pyruvate dehydrogenase complex were studied upon inactivation of the enzyme in an incomplete reaction mixture: in the presence of cofactors and pyruvate, and in the absence of electron acceptors. The substrate-dependent inactivation was shown to result in the modification of two sulfhydryl groups per mole of the enzyme, in the appearance of a maximum at 235 nm in the protein absorption spectrum, and in the involvement of 1.5 moles of the [2-14C]-pyruvate fragment per mole of the pyruvate dehydrogenase. The fragment-protein bond is acid-stable, labile in alkali, and breaks up in the presence of performic acid, neutral hydroxylamine and dithiothreitol. An acetyl-substituted form of pyruvate dehydrogenase appearing with the participation of sulfhydryl enzyme groups is suggested.