Differences in the fatty acid composition of soybean seed produced in northern and southern areas of the U.S.A.

The fatty acid composition of soybean (Glycine max) seeds was sensitive to the influence of both genotype and environment. To quantify their relative environmental sensitivities, four soybean cultivars, Wells, Wayne, Cutler and Union, plus two experimental lines, 9656 and 9686, developed for lower concentrations of linolenate, were grown in Indiana (northern area) and Mississippi (southern area) in 1981. Seeds produced in the two environments were analysed for total oil content and for fatty acid composition. Seeds produced in the southern area were slightly higher (20% vs 16%) in oil content, but weighed significantly less than those produced in the north. The oil content per seed of seeds produced in the south was only 51% of the oil content of seeds produced in the north. Seeds produced in the south were significantly lower in both myristate and linolenate, but significantly higher in oleate than seeds produced in the north. Genotype by environment interactions for many oil quality measurements were largely attributable to the responses of the lines 9656 and 9686. These results indicate that higher environmental temperature reduced the linolenate concentration of soybean oil.     

A stabilized demethoxyviridin derivative inhibits PI3 kinase

The viridins like demethoxyviridin (Dmv) and wortmannin (Wm) are nanomolar inhibitors of the PI3 kinases, a family of enzymes that play key roles in a host of regulatory processes. Central to the use of these compounds to investigate the role of PI3 kinase in biological systems, or as scaffolds for drug development, are the interrelated issues of stability, chemical reactivity, and bioactivity as inhibitors of PI3 kinase. We found that Dmv was an even more potent inhibitor of PI3 kinase than Wm. However, Dmv was notably less stable than Wm in PBS, with a half-life of 26 min versus Wm’s half-life of 3470 min. Dmv, like Wm, disappeared in culture media with a half-life of less than 1 min. To overcome Dmv’s instability, it was esterified at the C1 position, and then reacted with glycine at the C20 position. The resulting Dmv derivative, termed SA–DmvC20-Gly had a half-life of 218 min in PBS and 64 min in culture media. SA–DmvC20-Gly underwent an exchange reaction at the C20 position with N-acetyl lysine in a manner similar to a WmC20 derivative, WmC20-Proline. SA–DmvC20-Gly inhibited PI3 kinase with an IC₅₀ of 44 nM, compared to Wm’s IC₅₀ of 12 nM. These results indicate that the stability of Dmv can be manipulated by reactions at the C1 and C20 positions, while substantially maintaining its ability to inhibit PI3 kinase. Our results indicate it may be possible to obtain stabilized Dmv derivatives for use as PI3 kinase inhibitors in biological systems.     

Sécrétions apocrines dans le tractus génital mâle: Roles potentiels dans la maturation des gamètes

Apocrine secretory vesicles have been observed in the lumen of several ducts of the male genital tract, namely the epididymis and vas deferens. Initially considered to be tissue-fixation artefacts, they are now recognized as genuine elements, which might play physiological roles in terms of sperm maturation. The aim of this review is to present these vesicles observed in various mammalian species and to describe their respective organization, content and putative roles.     

Evaluating the Metal Tolerance Capacity of Microbial Communities Isolated from Alberta Oil Sands Process Water

Anthropogenic activities have resulted in the intensified use of water resources. For example, open pit bitumen extraction by Canada’s oil sands operations uses an estimated volume of three barrels of water for every barrel of oil produced. The waste tailings–oil sands process water (OSPW)–are stored in holding ponds, and present an environmental concern as they are comprised of residual hydrocarbons and metals. Following the hypothesis that endogenous OSPW microbial communities have an enhanced tolerance to heavy metals, we tested the capacity of planktonic and biofilm populations from OSPW to withstand metal ion challenges, using Cupriavidus metallidurans, a known metal-resistant organism, for comparison. The toxicity of the metals toward biofilm and planktonic bacterial populations was determined by measuring the minimum biofilm inhibitory concentrations (MBICs) and planktonic minimum inhibitory concentrations (MICs) using the MBEC ™ assay. We observed that the OSPW community and C. metallidurans had similar tolerances to 22 different metals. While thiophillic elements (Te, Ag, Cd, Ni) were found to be most toxic, the OSPW consortia demonstrated higher tolerance to metals reported in tailings ponds (Al, Fe, Mo, Pb). Metal toxicity correlated with a number of physicochemical characteristics of the metals. Parameters reflecting metal-ligand affinities showed fewer and weaker correlations for the community compared to C. metallidurans, suggesting that the OSPW consortia may have developed tolerance mechanisms toward metals present in their environment.     

Coordination complexes as molecular glue for immobilization of antibodies on cyclic olefin copolymer surfaces

A novel metal-based chelating method has been used to provide an order of magnitude increase in immunoassay performance on cyclic olefin copolymer (COC) plastics compared with passive binding. COCs are hydrophobic, and without surface modification they are often unsuitable for applications where protein adhesion is desired. When interacting with the bare plastic, the majority of the bound proteins will be denatured and become nonfunctional. Many of the surface modification techniques reported to date require costly equipment setup or the use of harsh reaction conditions. Here, we have successfully demonstrated the use of a simple and quick metal chelation method to increase the sensitivity, activity, and efficiency of protein binding to COC surfaces. A detailed analysis of the COC surfaces after activation with the metal complexes is presented, and the immunoassay performance was studied using three different antibody pairs.     

ULTRASTRUCTURE OF EARLY DEVELOPMENT IN THE FEMALE REPRODUCTIVE SYSTEM OF POLYSIPHONIA HARVEYI BAILEY (CERAMIALES,RHODOPHYTA)1

Prefertilization and immediate postfertilization development in the female reproductive branch of Polysiphonia harveyi (Bailey) was studied with the electron microscope. Results pertaining to prefertilization morphology and development are consistent with those established in earlier light microscopic studies, but several unexpected ultrastructural characteristics were discovered. The mature carpogonium was found to have double membrane-bound vacuoles of nuclear origin and the carpogonial nucleus contained a nucleolus with a distinctive crystalline lattice. Trichogynes lacked a nucleus. Of particular interest was the discovery of a highly structured channel of smooth endoplasmic reticulum (SER) which extended uninterrupted, except for pit connections, through the carpogonial branch. It is suggested that the message of fertilization is conducted through the SER channel from the carpogonium to the support cell. Few observations were made on postfertilization branches, but evidence of direct fusion between the carpogonium and auxiliary cell was fairly conclusive. Pit plugs in the female branch were found to be of three morphological types differing by the presence and number of pit membranes. We have designated these plugs Type I–III since differential functioning was not fully ascertained. Our data suggest that pit membranes may serve to stabilize the plug and that those plugs without membranes are more readily dismantled to allow cytoplasmic continuity between cells.     

TRACHEID LENGTH AS AN ECOTYPIC CHARACTER IN ACER NEGUNDO L.

Laboratory germinated seedlings of Acer negundo grown under controlled environmental conditions showed patterns of decreasing cell length (tracheids) with decrease in length of growing season of parental tree's habitat. Populations tested represented a range in latitude of 15 degrees (Texas to Canada) and the results indicate populational response to shorter growing seasons being reflected in xylem development.     

Active Vision during Action Execution,Observation and Imagery: Evidence for Shared Motor Representations

The concept of shared motor representations between action execution and various covert conditions has been demonstrated through a number of psychophysiological modalities over the past two decades. Rarely, however, have researchers considered the congruence of physical, imaginary and observed movement markers in a single paradigm and never in a design where eye movement metrics are the markers. In this study, participants were required to perform a forward reach and point Fitts’ Task on a digitizing tablet whilst wearing an eye movement system. Gaze metrics were used to compare behaviour congruence between action execution, action observation, and guided and unguided movement imagery conditions. The data showed that participants attended the same task-related visual cues between conditions but the strategy was different. Specifically, the number of fixations was significantly different between action execution and all covert conditions. In addition, fixation duration was congruent between action execution and action observation only, and both conditions displayed an indirect Fitts’ Law effect. We therefore extend the understanding of the common motor representation by demonstrating, for the first time, common spatial eye movement metrics across simulation conditions and some specific temporal congruence for action execution and action observation. Our findings suggest that action observation may be an effective technique in supporting motor processes. The use of video as an adjunct to physical techniques may be beneficial in supporting motor planning in both performance and clinical rehabilitation environments.