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.     

The extended interactions and Gla domain of blood coagulation factor Xa

The serine protease factor Xa (FXa) is inhibited by ecotin with picomolar affinity. The structure of the tetrameric complex of ecotin variant M84R (M84R) with FXa has been determined to 2.8 A. Substrate directed induced fit of the binding interactions at the S2 and S4 pockets modulates the discrimination of the protease. Specifically, the Tyr at position 99 of FXa changes its conformation with respect to incoming ligand, changing the size of the S2 and S4 pockets. The role of residue 192 in substrate and inhibitor recognition is also examined. Gln 192 from FXa forms a hydrogen bond with the P2 carbonyl group of ecotin. This confirms previous biochemical and structural analyses on thrombin and activated protein C, which suggested that residue 192 may play a more general role in mediating the interactions between coagulation proteases and their inhibitors. The structure of ecotin M84R-FXa (M84R-FXa) also reveals the structure of the Gla domain in the presence of Mg(2+). The first 11 residues of the domain assume a novel conformation and likely represent an intermediate folding state of the domain.     

A target within the target: probing cruzain's P1' site to define structural determinants for the Chagas' disease protease

BACKGROUND: Cysteine proteases of the papain superfamily are present in nearly all groups of eukaryotes and play vital roles in a wide range of biological processes and diseases, including antigen and hormone processing, bacterial infection, arthritis, osteoporosis, Alzheimer's disease and cancer-cell invasion. Because they are critical to the life-cycle progression of many pathogenic protozoa, they represent potential targets for selective inhibitors. Chagas' disease, the leading cause of death due to heart disease in Latin American countries, is transmitted by Trypanosoma cruzi. Cruzain is the major cysteine protease of T cruzi and has been the target of extensive structure-based drug design. RESULTS: High-resolution crystal structures of cruzain bound to a series of potent phenyl-containing vinyl-sulfone, sulfonate and sulfonamide inhibitors have been determined. The structures show a consistent mode of interaction for this family of inhibitors based on a covalent Michael addition formed at the enzyme's active-site cysteine, hydrophobic interactions in the S2 substrate-binding pocket and a strong constellation of hydrogen bonding in the S1' region. CONCLUSIONS: The series of vinyl-sulfone-based inhibitors examined in complex with cruzain was designed to probe recognition and binding potential of an aromatic-rich region of the enzyme. Analysis of the interactions formed shows that aromatic interactions play a less significant role, whereas the strength and importance of hydrogen bonding in the conformation adopted by the inhibitor upon binding to the enzyme was highlighted. A derivative of one inhibitor examined is currently under development as a therapeutic agent against Chagas' disease.     

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.