Washington State University

About: Washington State University is a education organization based out in Pullman, Washington, United States. It is known for research contribution in the topics: Population & Gene. The organization has 26947 authors who have published 57736 publications receiving 2341509 citations. The organization is also known as: WSU & Wazzu.

Life history and the ecology of stress: how do glucocorticoid hormones influence life-history variation in animals?

Abstract: Summary 1. Glucocorticoids hormones (GCs) are intuitively important for mediation of age-dependent vertebrate life-history transitions through their effects on ontogeny alongside underpinning variation in life-history traits and trade-offs in vertebrates. These concepts largely derive from the ability of GCs to alter energy allocation, physiology and behaviour that influences key life-history traits involving age-specific life-history transitions, reproduction and survival. 2. Studies across vertebrates have shown that the neuroendocrine stress axis plays a role in the developmental processes that lead up to age-specific early life-history transitions. While environmental sensitivity of the stress axis allows for it to modulate the timing of these transitions within species, little is known as to how variation in stress axis function has been adapted to produce interspecific variation in the timing of life-history transitions. 3. Our assessment of the literature confirms that of previous reviews that there is only equivocal evidence for correlative or direct functional relationships between GCs and variation in reproduction and survival. We conclude that the relationships between GCs and life-history traits are complex and general patterns cannot be easily discerned with current research approaches and experimental designs. 4. We identify several future research directions including: (i) integration of proximate and ultimate measures, including longitudinal studies that measure effects of GCs on more than one life-history trait or in multiple environmental contexts, to test explicit hypotheses about how GCs and life-history variation are related and (ii) the measurement of additional factors that modulate the effects of GCs on life-history traits (e.g. GC receptors and binding protein levels) to better infer neurendocrine stress axis actions. 5. Conceptual models of HPA/I axis actions, such as allostatic load and reactive scope, to some extent explicitly predict the role of GCs in a life-history context, but are descriptive in nature. We propose that GC effects on life-history transitions, survival probabilities and fecundity can be modelled in existing quantitative demographic frameworks to improve our understanding of how GC variation influences life-history evolution and GC-mediated effects on population dynamics

Detection of subgroup III geminivirus isolates in leaf extracts by degenerate primers and polymerase chain reaction.

Abstract: The DNA of several monopartite and bipartite whitefly-transmitted (WFT) geminiviruses was amplified from a viral template present in infected leaves after either direct addition of clarified plant extracts to an otherwise complete polymerase chain reaction (PCR) mix or after immobilization of template to microfuge tubes. A degenerate primer pair was designed to specifically target the middle or 'core' region of the capsid protein gene of subgroup III geminivirus isolates and amplify a viral DNA fragment of approximately 550 bp. Using this method, a single PCR product of the expected size (550 bp), as estimated by agarose gel electrophoresis, was amplifiable from plants infected with a representative set of subgroup III geminivirus isolates with a broad biogeographic base. That the 550-bp PCR product had a geminiviral gene origin was demonstrated by direct sequencing of the 550-bp fragments (yielding approximately 470 to 490 bases of informative sequence) and was validated through comparison (alignment) of the sequences with the published DNA sequences of several well-characterized WFT geminiviruses. Analogous viral fragments were not detectable by PCR with the subgroup III core coat protein primers and extracts of plants infected with either subgroup I or II geminivirus isolates. The demonstrated exclusive specificity of the assay for subgroup III geminiviruses offers a highly simplified PCR-based assay that permits the detection of a geographically diverse collection of WFT geminiviruses infecting cultivated crops, ornamentals, and weed hosts with minimal sample preparation. This approach is highly useful for the amplification of subgroup III geminiviral DNA templates from total nucleic acid extracts from infected plants and partially purified virion preparations.

Electromagnetic fields act via activation of voltage-gated calcium channels to produce beneficial or adverse effects

Abstract: The direct targets of extremely low and microwave frequency range electromagnetic fields (EMFs) in producing non-thermal effects have not been clearly established. However, studies in the literature, reviewed here, provide substantial support for such direct targets. Twenty-three studies have shown that voltage-gated calcium channels (VGCCs) produce these and other EMF effects, such that the L-type or other VGCC blockers block or greatly lower diverse EMF effects. Furthermore, the voltage-gated properties of these channels may provide biophysically plausible mechanisms for EMF biological effects. Downstream responses of such EMF exposures may be mediated through Ca2+ /calmodulin stimulation of nitric oxide synthesis. Potentially, physiological/therapeutic responses may be largely as a result of nitric oxide-cGMP-protein kinase G pathway stimulation. A well-studied example of such an apparent therapeutic response, EMF stimulation of bone growth, appears to work along this pathway. However, pathophysiological responses to EMFs may be as a result of nitric oxide-peroxynitrite-oxidative stress pathway of action. A single such well-documented example, EMF induction of DNA single-strand breaks in cells, as measured by alkaline comet assays, is reviewed here. Such single-strand breaks are known to be produced through the action of this pathway. Data on the mechanism of EMF induction of such breaks are limited; what data are available support this proposed mechanism. Other Ca2+ -mediated regulatory changes, independent of nitric oxide, may also have roles. This article reviews, then, a substantially supported set of targets, VGCCs, whose stimulation produces non-thermal EMF responses by humans/higher animals with downstream effects involving Ca2+ /calmodulin-dependent nitric oxide

Automatic Video Classification: A Survey of the Literature

Abstract: There is much video available today. To help viewers find video of interest, work has begun on methods of automatic video classification. In this paper, we survey the video classification literature. We find that features are drawn from three modalities - text, audio, and visual - and that a large variety of combinations of features and classification have been explored. We describe the general features chosen and summarize the research in this area. We conclude with ideas for further research.