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.

BIOSYNTHESIS OF ASCORBIC ACID IN PLANTS: A Renaissance.

Abstract: ▪ Abstract The structure of the familiar antioxidant L-ascorbic acid (vitamin C) was described in 1933 yet remarkably, its biosynthesis in plants remained elusive until only recently. It became clear from radioisotopic labeling studies in the 1950s that plant ascorbic acid biosynthesis does not proceed in toto via a route similar to that in mammals. The description in 1996 of an Arabidopsis thaliana mutant deficient in ascorbic acid prompted renewed research effort in this area, and subsequently in 1998 a new pathway was discovered that is backed by strong biochemical and molecular genetic evidence. This pathway proceeds through the intermediates GDP-D-mannose, L-galactose, and L-galactono-1,4-lactone. Much research has focused on the properties of the terminal enzyme responsible for conversion of the aldonolactone to ascorbate, and on related enzymes in both mammals and fungi. Two of the plant biosynthetic genes have been studied at the molecular level and additional ascorbate-deficient A. thaliana mutan...

Time course of extracellular dopamine and behavioral sensitization to cocaine. II. Dopamine perikarya

Abstract: Cocaine was administered daily (15 mg/kg, i.p. x 1 d followed by 30 mg/kg, i.p. x 5 d) to produce behavioral sensitization. Using microdialysis in the ventral tegmental area and medial substantia nigra, the effect of repeated cocaine was examined on the extracellular levels of dopamine. One day after discontinuing repeated cocaine injections, an acute challenge with cocaine (15 mg/kg, i.p.) produced a significant elevation in extracellular dopamine compared to rats pretreated with daily saline (x6 d). The augmentation in extracellular dopamine persisted longer than the sensitized behavioral response. In contrast, 14 d after discontinuing daily cocaine, the increase in extracellular dopamine produced by an acute cocaine challenge was not augmented, although behavioral sensitization was present. In separate animals, the basal concentration of dopamine in the ventral tegmental area/medial substantia nigra was measured by determining the concentration of dopamine at which no net flux occurred across the dialysis membrane in vivo. One day after discontinuing daily treatments, the basal level of extracellular dopamine in the cocaine pretreated rats was significantly elevated over the level in saline- pretreated animals (1.3 nM vs. 0.8 nM). By 14 d after the last daily injection, the basal levels of dopamine were equivalent in cocaine- and saline-pretreated animals. It is concluded that daily cocaine injections produce a transient alteration in the regulation of somatodendritic dopamine release. While such changes are not responsible for the long-term behavioral sensitization produced by repeated cocaine administration, they may be involved in the initiation of behavioral sensitization.

Quorum Sensing: A New Biofouling Control Paradigm in a Membrane Bioreactor for Advanced Wastewater Treatment

Abstract: Bacteria regulate specific group behaviors such as biofilm formation in response to population density using small signal molecules called autoinducers (quorum sensing, QS). In this study, the concept of bacterial QS was applied to membrane bioreactors (MBRs) for advanced wastewater treatment as a new biofouling control paradigm. The research was conducted in three phases: (1) demonstrate the presence of the autoinducer signal in MBRs, (2) correlate QS activity and membrane biofouling, (3) apply QS-based membrane biofouling control. A bioassay with Agrobacterium tumefaciens reporter strain proved that N-acyl homoserine lactone (AHL) autoinducers were produced in the MBR. Furthermore, thin-layer chromatographic analysis identified at least three different AHLs in the biocake, of which N-octanoyl-homoserine lactone was the most abundant. During continuous MBR operation, the biocake showed strong AHL activity simultaneously with abrupt increase in the transmembrane pressure, which implies that QS is in close...