Oregon State University

About: Oregon State University is a education organization based out in Corvallis, Oregon, United States. It is known for research contribution in the topics: Population & Climate change. The organization has 28192 authors who have published 64044 publications receiving 2634108 citations. The organization is also known as: Oregon Agricultural College & OSU.

Motor Competence and its Effect on Positive Developmental Trajectories of Health

Abstract: In 2008, Stodden and colleagues took a unique developmental approach toward addressing the potential role of motor competence in promoting positive or negative trajectories of physical activity, health-related fitness, and weight status. The conceptual model proposed synergistic relationships among physical activity, motor competence, perceived motor competence, health-related physical fitness, and obesity with associations hypothesized to strengthen over time. At the time the model was proposed, limited evidence was available to support or refute the model hypotheses. Over the past 6 years, the number of investigations exploring these relationships has increased significantly. Thus, it is an appropriate time to examine published data that directly or indirectly relate to specific pathways noted in the conceptual model. Evidence indicates that motor competence is positively associated with perceived competence and multiple aspects of health (i.e., physical activity, cardiorespiratory fitness, muscular strength, muscular endurance, and a healthy weight status). However, questions related to the increased strength of associations across time and antecedent/consequent mechanisms remain. An individual’s physical and psychological development is a complex and multifaceted process that synergistically evolves across time. Understanding the most salient factors that influence health and well-being and how relationships among these factors change across time is a critical need for future research in this area. This knowledge could aid in addressing the declining levels of physical activity and fitness along with the increasing rates of obesity across childhood and adolescence.

Long‐term dynamics of pine and hardwood litter in contrasting environments: toward a global model of decomposition

Abstract: We analysed data on mass loss after five years of decomposition in the field from both fine root and leaf litters from two highly contrasting trees, Drypetes glattca, a tropical hardwood tree from Puerto Rico, and pine species from North America as part of the Long-Term lntersite Decomposition Experiment (LIDEn. L1DET is a reciprocal litter­ bag study involving the transplanting of litter from 27 species across 28 sites in North and Central America reflecting a wide variety of natural and managed ecosystems and climates, from Arctic tundra to tropical rainforest. After 5 years, estimated k-values ranged from 0.032 to 3.734, lengths of Phase I (to 20% mass remaining) from 0.49 to 47.92 years, and fractional mass remaining from 0 to 0.81. Pine litter decomposed more slowly than Drypetes litter, supporting the notion of strong control of substrate quality over decomposition rates. Climate exerted strong and consistent effects on decomposi­ tion. Neither mean annual temperature or precipitation alone explained the global pat­ tern of decomposition; variables including both moisture availability and temperature (i.e. actual evapotranspiration and DEFAC from the CENTURY model) were generally more robust than single variables. Across the LIDET range, decomposition of fine roots exhibited a QI0 of 2 and was more predictable than that of leaves, which had a higher QI0 and greater variability. Roots generally decomposed more slowly than leaves, regardless of genus, but the ratio of above- to belowground decomposition rates differed sharply across ecosystem types. Finally, Drypetes litter decomposed much more rapidly than pine litter in 'broad leaved habitats' than in 'conifer habitats', evidence for a 'home-field advantage' for this litter. These results collectively suggest that relatively simple models can predict decomposition based on litter quality and regional climate, but that ecosystem-specific problems may add complications.

Glutathione: Toxicological Implications

Abstract: Glutathione as reduced glutathione (GSH) and as the disulfide (GSSG) is a unique peptide that continues to interest toxicologists-as reflected in the numerous symposia and reviews ( 1-6). This article undertakes to describe the role of mitochondrial glutathione in cellular response to toxic exposures that include loss of the homeostases of Ca2+ and protein thiols. Because of the numerous reviews on the glutathione S-transferases (7-10), only the per­ oxidase activity of membrane-associated glutathione S-transferases is dis­ cussed. Mammalian cells have evolved protective mechanisms to minimize in­ jurious events that result from toxic chemicals and normal oxidative products of cellular metabolism. A major endogenous protective system is the glu­ tathione redox cycle (2). Glutathione is present in high concentrations as GSH in most mammalian cells (generally in the millimolar range), with minor fractions being GSSG, mixed disulfides of GSH and other cellular thiols, and minor amounts of thioethers ( 1) . GSH acts both as a nucleophilic "scavenger" of numerous compounds and their metabolites, via enzymatic and chemical mechanisms, converting electrophilic centers to thioether bonds, and as a substrate in the GSH peroxidase-mediated destruction of hydroperoxides. GSH depletion to about 20-30% of total glutathione levels can impair the cell's defense against the toxic actions of such compounds and may lead to cell injury and death (3, 1 1) .

Cellular mechanisms of Cnidarian bleaching: stress causes the collapse of symbiosis

Abstract: Cnidarian bleaching is a breakdown in the mutualistic symbiosis between host Cnidarians, such as reef building corals, and their unicellular photosynthetic dinoflagellate symbionts. Bleaching is caused by a variety of environmental stressors, most notably elevated temperatures associated with global climate change in conjunction with high solar radiation, and it is a major contributor to coral death and reef degradation. This review examines the underlying cellular events that lead to symbiosis dysfunction and cause bleaching, emphasizing that, to date, we have only some pieces of a complex cellular jigsaw puzzle. Reactive oxygen species (ROS), generated by damage to both photosynthetic and mitochondrial membranes, is shown to play a central role in both injury to the partners and to inter-partner communication of a stress response. Evidence is presented that suggests that bleaching is a host innate immune response to a compromised symbiont, much like innate immune responses in other host-microbe interactions. Finally, the elimination or exit of the symbiont from host tissues is described through a variety of mechanisms including exocytosis, host cell detachment and host cell apoptosis.

Assembling the fungal tree of life: progress, classification, and evolution of subcellular traits

Abstract: Based on an overview of progress in molecular systematics of the true fungi (Fungi/Eumycota) since 1990, little overlap was found among single-locus data matrices, which explains why no large-scale multilocus phylogenetic analysis had been undertaken to reveal deep relationships among fungi. As part of the project ‘‘Assembling the Fungal Tree of Life’’ (AFTOL), results of four Bayesian analyses are reported with complementary bootstrap assessment of phylogenetic confidence based on (1) a combined two-locus data set (nucSSU and nucLSU rDNA) with 558 species representing all traditionally recognized fungal phyla (Ascomycota, Basidiomycota, Chytridiomycota, Zygomycota) and the Glomeromycota, (2) a combined three-locus data set (nucSSU, nucLSU, and mitSSU rDNA) with 236 species, (3) a combined three-locus data set (nucSSU, nucLSU rDNA, and RPB2) with 157 species, and (4) a combined four-locus data set (nucSSU, nucLSU, mitSSU rDNA, and RPB2) with 103 species. Because of the lack of complementarity among single-locus data sets, the last three analyses included only members of the Ascomycota and Basidiomycota. The four-locus analysis resolved multiple deep relationships within the Ascomycota and Basidiomycota that were not revealed previously or that received only weak support in previous studies. The impact of this newly discovered phylogenetic structure on supraordinal classifications is discussed. Based on these results and reanalysis of subcellular data, current knowledge of the evolution of septal features of fungal hyphae is synthesized, and a preliminary reassessment of ascomal evolution is presented. Based on previously unpublished data and sequences from GenBank, this study provides a phylogenetic synthesis for the Fungi and a framework for future phylogenetic studies on fungi.