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.

Long-term effects of organic and conventional farming on soil erosion

Abstract: Conventional, intensive tillage farming systems have greatly increased crop production and labour efficiency But, serious questions are being raised about the energy-intensive nature of these systems and their adverse effects on soil productivity and environmental quality1,2 This concern has led to an increasing interest in organic farming systems because they may reduce some of the negative effects of conventional agriculture on the environment3,4 We compare the long-term effects (since 1948) of organic and conventional farming on selected properties of the same soil The organically-farmed soil had significantly higher organic matter content, thicker topsoil depth, higher polysaccharide content, lower modulus of rupture and less soil erosion than the conventionally-farmed soil This study indicates that, in the long term, the organic farming system was more effective than the conventional farming system in reducing soil erosion and, therefore, in maintaining soil productivity

Polypeptide signaling for plant defensive genes exhibits analogies to defense signaling in animals.

Abstract: The activation of plant defensive genes in leaves of tomato plants in response to herbivore damage or mechanical wounding is mediated by a mobile 18-amino acid polypeptide signal called systemin. Systemin is derived from a larger, 200-amino acid precursor called prosystemin, similar to polypeptide hormones and soluble growth factors in animals. Systemin activates a lipid-based signaling cascade, also analogous to signaling systems found in animals. In plants, linolenic acid is released from membranes and is converted to the oxylipins phytodienoic acid and jasmonic acid through the octadecanoid pathway. Plant oxylipins are structural analogs of animal prostaglandins which are derived from arachidonic acid in response to various signals, including polypeptide factors. Constitutive overexpression of the prosystemin gene in transgenic tomato plants resulted in the overproduction of prosystemin and the abnormal release of systemin, conferring a constitutive overproduction of several systemic wound-response proteins (SWRPs). The data indicate that systemin is a master signal for defense against attacking herbivores. The same defensive proteins induced by wounding are synthesized in response to oligosaccharide elicitors that are generated in leaf cells in response to pathogen attacks. Inhibitors of the octadecanoid pathway, and a mutation that interrupts this pathway, block the induction of SWRPs by wounding, systemin, and oligosaccharide elicitors, indicating that the octadecanoid pathway is essential for the activation of defense genes by all of these signals. The tomato mutant line that is functionally deficient in the octadecanoid pathway is highly susceptible to attacks by Manduca sexta larvae. The similarities between the defense signaling pathway in tomato leaves and those of the defense signaling pathways of macrophages and mast cells of animals suggests that both the plant and animal pathways may have evolved from a common ancestral origin.

Amphetamine injection into the ventral mesencephalon sensitizes rats to peripheral amphetamine and cocaine.

Abstract: The daily administration of indirect dopamine agonists, including amphetamine and cocaine, results in a progressive increase in the behavioral stimulant effect of these drugs. Behavioral augmentation also has been shown with opioids such as morphine, and it is known that a stimulant action on dopaminergic perikarya in the ventromedial mesencephalon is critical to the development of behavioral sensitization to morphine. To determine if amphetamine-induced behavioral sensitization might also involve the mesencephalic dopamine neurons, amphetamine was microinjected daily for 2 days into regions of the rat brain containing dopamine cell bodies (A10 and A9 dopamine regions), or dopamine terminals (nucleus accumbens and striatum), and 6 days later amphetamine was given peripherally. It was found that daily amphetamine injection into the A10 or A9 dopamine region, but not into the dopamine terminal fields, significantly potentiated the motor stimulant effect of peripherally administered amphetamine. The behavioral sensitization produced by intracranial injection of amphetamine was found to be dose-dependent. Intra-A10 injection of amphetamine also was found to potentiate the motor stimulant effect of peripheral cocaine. These data indicate that an action by amphetamine in the A10 and A9 dopamine regions may play a critical role in the development of behavioral sensitization.