Forest harvest legacies control dissolved organic carbon export in small watersheds,western Oregon

This study examined physical and biological controls on dissolved organic carbon (DOC) fluxes from conifer-forest watersheds in the H.J. Andrews Experimental Forest of Oregon. We tested how DOC export was related to streamflow and legacies of wood on the forest floor three to five decades after harvest of old-growth forest in seven watersheds spanning the rain to snow elevation gradient. Three watersheds had old-growth forest and four had 30 to 50-year-old forest established after clearcutting of old-growth forest. Mean annual DOC flux in the watersheds was related to the biomass of forest floor wood, which was two or three times higher in watersheds with old-growth forest compared to young forest, and was inversely related to elevation, a measure of snowpack depth and duration. In contrast, fluxes of inorganic elements such as Si and Ca did not vary with harvest history or forest floor characteristics. Annual fluxes of DOC, Si, and Ca were linearly related to annual runoff, and annual volume-weighted concentrations of these ions declined by?<?0.6% with several-fold increases in annual runoff. Across all years, DOC concentrations peaked before the peak of the hydrograph in all watersheds, which we interpret as representing movement, likely via preferential and surficial flow, of organic materials mineralized and solubilized during the long dry summers in this ecosystem. DOC concentrations relative to stream flow exhibited clockwise hysteresis loops in each water year, also suggesting that soluble DOC produced in the dry summer is exported in the fall. DOC concentration differences between reference and harvested watersheds also peaked in late summer or early fall, suggesting that the source of the additional DOC from reference watersheds came from coarse woody debris that remains moist during the dry summers and that was significantly greater in watersheds with elevated DOC. Taken together, our results suggest that forest floor wood is a previously unappreciated control on the supply of DOC that can be exported, and runoff is a secondary control on total DOC flux to streams. The legacy of forest harvest on DOC flux can be observed for decades, as total ecosystem carbon stocks, especially coarse woody debris, may require centuries to develop after old-growth forest harvest.     

Brain protein synthesis rates are not sensitive to elevated GABA,taurine, or glycine

The effects of elevated levels of GABA, glycine, or taurine on the rate of protein synthesis in plasma, brain, liver, and muscle of adult mice were measured in in vivo experiments after a flooding dose of labeled valine. Elevation of these amino acids caused hypothermia; keeping the animals in an incubator maintained physiological body temperature. The increase in GABA or glycine did not affect the rate of protein synthesis in these tissues to a significant degree. The increase in taurine levels caused inhibition of valine incorporation in plasma, liver, and muscle, while brain protein synthesis was unaffected. When glycine was increased in brain, the uptake of labeled free valine in the brain was greater.     

Effects of 17ß-estradiol and progesterone on the levels of prostaglandins F2α and E in human endometrium

17ß-estradiol and progesterone were administered to post-menopausal women to determine their effects on the capacity of human endometrium to synthesize prostaglandins (PGs) F₂α and E. Basal amounts of PGF₂α and PGE synthesized by endometrium exposed to 17ß-estradiol and progesterone were significantly higher than the levels produced by endometrium exposed to 17ß-estradiol alone (p < 0.02 for both PGs). Levels found in the former endometrium were broadly comparable to levels in secretory endometrium and in the latter to amounts found in proliferative endometrium of spontaneous, ovulatory cycles.     

Changes in antioxidant enzymes and organic solutes associated with adaptation of citrus cells to salt stress

Embryogenic callus cultures of lemon (Citrus limon L. Burm f. cv Verna), were selected for resistance to salt stress (170 mM NaCl). Inorganic analysis showed that selected callus accumulated more Na⁺ and Cl^- ions than the non-selected one. Moreover, the salt-tolerant C. limon callus exhibited an increase in the activity of antioxidant enzymes involved in oxygen metabolism, with the induction of a new superoxide dismutase isozyme and an increase of the peroxidase activity while the catalase activity was unchanged. Proline and total sugar, mainly sucrose, concentrations increases significantly in salt-tolerant cells as compared to control cells. On the other hand, the selected cell line also showed an increase in choline and glycine betaine, but to lesser extent.Abbreviations BSA bovine serum albumin - P5CR pyrroline-5-carboxylated reductase - QAC quaternary ammonium compounds - SOD superoxide dismutase     

Genome analysis of the moss Physcomitrella patens (Hedw.) B.S.G.

A wild-type (WT) strain of the moss Physcomitrella patens (Hedw.) B.S.G., two mutants derived from it (PC22 and P24), and a somatic hybrid, PC22(+)P24, were analysed. Staining of metaphases revealed 54±2 chromosomes in the somatic hybrid and 27 chromosomes in the wild type and the two mutants. Using flow cytometry (FCM), DNA contents were calculated to be 0.6 pg (WT, PC22), 1.2 pg (P24), and 1.6 pg (PC22(+)P24) per nucleus, respectively. Southern hybridization provided evidence for at least one family of highly repetitive DNA and, furthermore, revealed different amounts of repetitive DNA in the four genotypes. However, these sequences cannot account for the 100% increase in the nuclear DNA amount in mutant P24, relative to wild type. In FCM analyses every moss geno-type generated just one single peak of fluorescence, indicating an arrest in the cell cycle during the daytime. Thermal denaturation of wild-type DNA revealed a G+C content of 34.6% for total DNA and 38.6% for plastid DNA. A cDNA library of 1.2 × 10⁶ independent clones was established, from which sequences homologous to cab and rbcS, respectively, were isolated. These genes show significant homologies to those of higher plants, and, likewise, comprise multigene families. No restriction fragment length polymorphisms could be detected between the four moss genotypes using these cDNA probes.This article is based in part on doctoral studies of M.F. and MW at the University of Hamburg, Faculty of Biology     

Effect of weight loss on predicted cardiovascular risk: change in cardiac risk after bariatric surgery

Objective: Our goal was to assess the effect of bariatric surgery on cardiovascular risk estimations of preventable, long‐term adverse outcomes. Research Methods and Procedures: We performed a population‐based, historical cohort study between 1990 and 2003 of 197 consecutive patients from Olmsted County, MN, with Class II to III obesity (defined as BMI ≥35 kg/m²) treated with Roux‐en‐Y gastric bypass and 163 non‐operative patients assessed in a weight‐reduction program. We used the observed change in cardiovascular risk factors and risk models derived from data from the National Health and Nutrition Examination Survey (NHANES) I and the NHANES I Epidemiological Follow‐up Study (NHEFS) to calculate the predicted impact on cardiovascular events and mortality for the operative and non‐operative groups. Results: Mean follow‐up was 3.3 years. Hypertension, diabetes, and dyslipidemia all improved after bariatric surgery. The estimated 10‐year risk for cardiovascular events for the operative group decreased from 37% at baseline to 18% at follow‐up, while the estimated risk for the non‐operative group did not change from 30% at baseline to 30% at follow‐up. Risk modeling to predict 10‐year outcomes estimated 4 overall deaths and 16 cardiovascular events prevented by bariatric surgery per 100 patients compared with the non‐operative group. Conclusions: Bariatric surgery induces an improvement in cardiovascular risk factors in patients with Class II to III obesity. Weight loss predicts a major, 10‐year reduction in cardiovascular events and deaths. Bariatric surgery should be considered as an alternative approach to reduce cardiovascular risk in patients with Class II to III obesity.