Effect of estradiol-17β on glucose and proline uptake in plasma membrane vesicles from the R3230AC rat mammary carcinoma

Purified plasma membrane vesicles isolated from R3230AC rat mammary tumors displayed carrier-mediated and stereospecific uptake. Uptake was shown to be proportional to protein concentration, sensitive to increasing osmolarity, and inhibited only by substrates entering by the same carrier. Carrier-mediated glucose uptake was inhibited rapidly by estradiol-17β and phloretin in a dose-dependent manner, whereas proline uptake was not affected by estradiol-17β. The data suggest that the inhibition of glucose by estradiol and phloretin, originally observed in whole cells, occurs by an interaction of the steroid with a component on the plasma membrane. In contrast, the lack of effects of estradiol on proline transport into vesicles implies that intracellular components may have mediated the estrogen-induced effects observed in whole cells.     

Sorting out the functional role(s) of peroxisome proliferator-activated receptor-β/δ (PPARβ/δ) in cell proliferation and cancer

Peroxisome proliferator-activated receptor-β/δ (PPARβ/δ) has many beneficial physiological functions ranging from enhancing fatty acid catabolism, improving insulin sensitivity, inhibiting inflammation and increasing oxidative myofibers allowing for improved athletic performance. Thus, given the potential for targeting PPARβ/δ for the prevention and/or treatment of diseases including diabetes, dyslipidemias, metabolic syndrome and cancer, it is critical to clarify the functional role of PPARβ/δ in cell proliferation and associated disorders such as cancer. However, there is considerable controversy whether PPARβ/δ stimulates or inhibits cell proliferation. This review summarizes the literature describing the influence of PPARβ/δ on cell proliferation, with an emphasis toward dissecting the data that give rise to opposing hypotheses. Suggestions are offered to standardize measurements associated with these studies so that interlaboratory comparisons can be accurately assessed.     

Spring migration phenology of birds in the Northern Prairie region is correlated with local climate change

ABSTRACT In apparent response to recent periods of global warming, some migratory birds now arrive earlier at stopover sites and breeding grounds. However, the effects of this warming on arrival times vary among locations and species. Migration timing is generally correlated with temperature, with earlier arrival during warm years than during cold years, so local variation in climate change might produce different effects on migration phenology in different geographic regions. We examined trends in first spring arrival dates (FADs) for 44 species of common migrant birds in South Dakota (1971–2006) and Minnesota (1964–2005) using observations compiled by South Dakota and Minnesota Ornithologists’ Unions. We found significant trends in FAD over time for 20 species (18 arriving earlier and two later) in South Dakota and 16 species (all earlier) in Minnesota. Of these species, 10 showed similar significant trends for both states. All 10 of these species exhibited significantly earlier arrival, and all were early spring migrants, with median FADs before 10 April in both states. Eighteen of the 44 species showed significant negative correlations of FADs with either winter (December–February) or spring (arrival month plus previous month) temperatures in one or both states. Interestingly, spring temperatures in both South Dakota and Minnesota did not warm significantly from 1971–2006, but winter temperatures in both states warmed significantly over the same time period. This suggests that the warmer winters disproportionately affected early spring migrants, especially those associated with aquatic habitats (seven of the 10 species showing significantly earlier spring arrival in both states). The stronger response to climate change by early spring migrants in our study is consistent with the results of several other studies, and suggests that migrants, especially early migrants, are capable of responding to local temperature conditions experienced on wintering grounds or along the migration route.     

Developing the wool proteome

The wool proteome has been largely uncharted due to a lack of database coverage, poor protein extractability and dynamic range issues. Yet, investigating correlations between wool physical properties and protein content, or characterising UV-, heat- or processing-induced protein damage requires the availability of an identifiable and identified proteome.In this study we have achieved unprecedented wool proteome identification through a strategy of comprehensive data acquisition, iterative protein identification/validation and concurrent augmentation of the sequence database. Data acquisition comprised a range of different hyphenated MS techniques including LC–MS/MS, LC–MALDI, 2D-LC–MS/MS and SDS-PAGE LC–MS. Using iterative searching of databases and search result combination using ProteinScape, a systematic expansion of identifiable proteins in the sequence database was achieved. This was followed by extensive validation and rationalisation of the protein identifications. In total, 72 complete and 30 partial ovine-specific protein sequences were added to the database, and 113 wool proteins were identified.Enhanced access to ovine-specific protein identification and characterisation will facilitate all wool fibre protein chemistry and proteomics research.     

Thin‐Film Solar Cells with InP Absorber Layers Directly Grown on Nonepitaxial Metal Substrates

The design and performance of solar cells based on InP grown by the nonepitaxial thin‐film vapor–liquid–solid (TF‐VLS) growth technique is investigated. The cell structure consists of a Mo back contact, p‐InP absorber layer, n‐TiO₂ electron selective contact, and indium tin oxide transparent top electrode. An ex situ p‐doping process for TF‐VLS grown InP is introduced. Properties of the cells such as optoelectronic uniformity and electrical behavior of grain boundaries are examined. The power conversion efficiency of first generation cells reaches 12.1% under simulated 1 sun illumination with open‐circuit voltage (V_OC) of 692 mV, short‐circuit current (J_SC) of 26.9 mA cm^?2, and fill factor (FF) of 65%. The FF of the cell is limited by the series resistances in the device, including the top contact, which can be mitigated in the future through device optimization. The highest measured V_OC under 1 sun is 692 mV, which approaches the optically implied V_OC of ≈795 mV extracted from the luminescence yield of p‐InP.