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.

Rapid eruption of the Deccan flood basalts at the Cretaceous/Tertiary boundary

Abstract: The accumulation of flood basalts of the Deccan Traps, western India, is one of the most remarkable volcanic provinces on Earth in sheer extent and volume. These rocks are akin in composition and occurrence to other extensive continental basalt provinces, usually located near plate margins, but distributed worldwide and of various ages1. Recent interest in the Deccan flood basalts has increased with the suggestion that this volcanic activity may have coincided with mass faunal extinctions and/or meteorite impact at the Cretaceous/Tertiary boundary2–5; critical to these correlations are the age and age range of the volcanic rocks. Here we report 40Ar–39Ar geochronological results from stratigraphically controlled, geochemically well characterized tholeiitic basalts from the thickest sequence of the Deccan flood basalts, Western Ghats6. The samples dated span a section ∼2,000m thick, and range in age from 66.6 to 68.5 Myr. There is no significant difference in age from the stratigraphically oldest to the youngest rocks. It appears, then, that this sequence of lavas was erupted rapidly and can be correlated in time with events at the Cretaceous/Tertiary boundary.

Grazing-activated chemical defence in a unicellular marine alga

Abstract: Marine plankton use a variety of defences against predators, some of which affect trophic structure and biogeochemistry1. We have previously shown2 that, during grazing by the protozoan Oxyrrhis marina on the alga Emiliania huxleyi, dimethylsulphoniopropionate (DMSP) from the prey is converted to dimethyl sulphide (DMS) when lysis of ingested prey cells initiates mixing of algal DMSP and the enzyme DMSP lyase. Such a mechanism is similar to macrophyte defence reactions3,4. Here we show that this reaction deters protozoan herbivores, presumably through the production of highly concentrated acrylate, which has antimicrobial activity5. Protozoan predators differ in their ability to ingest and survive on prey with high-activity DMSP lyase, but all grazers preferentially select strains with low enzyme activity when offered prey mixtures. This defence system involves investment in a chemical precursor, DMSP, which is not self-toxic and has other useful metabolic functions. We believe this is the first report of grazing-activated chemical defence in unicellular microorganisms.

Subterfuge and manipulation: type III effector proteins of phytopathogenic bacteria.

Abstract: Diverse gram-negative bacteria deliver effector proteins into the cells of their eukaryotic hosts using the type III secretion system. Collectively, these type III effector proteins function to optimize the host cell environment for bacterial growth. Type III effector proteins are essential for the virulence of Pseudomonas syringae, Xanthomonas spp., Ralstonia solanacearum and Erwinia species. Type III secretion systems are also found in nonpathogenic pseudomonads and in species of symbiotic nitrogen-fixing Rhizobium. We discuss the functions of type III effector proteins of plant-associated bacteria, with an emphasis on pathogens. Plant pathogens tend to carry diverse collections of type III effectors that likely share overlapping functions. Several effectors inhibit host defense responses. The eukaryotic host targets of only a few type III effector proteins are currently known. We also discuss possible mechanisms for diversification of the suite of type III effector proteins carried by a given bacterial strain.

The susceptibility of small fruits and cherries to the spotted-wing drosophila, Drosophila suzukii

Abstract: BACKGROUND: The spotted-wing drosophila, Drosophila suzukii Matsumura, is native to Asia and was first detected in the North American mainland and Europe in 2008–2010. Drosophila suzukii is a serious economic pest to stone and small fruits because the female lays eggs within ripening fruit on a plant before harvest, which can lead to crop loss. The aim of this study was to evaluate the susceptibility of blackberries, blueberries, cherries, grapes, raspberries and strawberries to D. suzukii among various ripeness stages and cultivars. RESULTS: In 26 no-choice and choice replicated laboratory cage tests on ripeness stages, fruits were generally susceptible to D. suzukii once fruits started to color. Few D. suzukii developed on green fruit, wine grapes or overripe blueberries. In seven cultivar tests, D. suzukii preferences ranged from no differences to fourfold differences for specific cultivars of blackberries, blueberries, raspberries and wine grapes. As brix levels increased, more eggs were laid or more D. suzukii developed on blackberries, blueberries, cherries, raspberries and strawberries. In a choice test of various fruit types, strawberries, raspberries, blackberries, cherries and blueberries were more susceptible to D. suzukii than green table grapes ('Thompson'). CONCLUSION: The results suggest that fruits may become susceptible to D. suzukii as they start to turn color, and that specific varieties of grapes and overripe blueberries have low susceptibility to D. suzukii. Copyright © 2011 Society of Chemical Industry

Lidar remote sensing of above‐ground biomass in three biomes

Abstract: Estimation of the amount of carbon stored in forests is a key challenge for understanding the global carbon cycle, one which remote sensing is expected to help address. However, estimation of carbon storage in moderate to high biomass forests is difficult for conventional optical and radar sensors. Lidar (light detection and ranging) instruments measure the vertical structure of forests and thus hold great promise for remotely sensing the quantity and spatial organization of forest biomass. In this study, we compare the relationships between lidar-measured canopy structure and coincident field measurements of above-ground biomass at sites in the temperate deciduous, temperate coniferous, and boreal coniferous biomes. A single regression for all three sites is compared with equations derived for each site individually. The single equation explains 84% of variance in above-ground biomass (P < 0.0001) and shows no statistically significant bias in its predictions for any individual site.