University of Missouri

About: University of Missouri is a education organization based out in Columbia, Missouri, United States. It is known for research contribution in the topics: Population & Poison control. The organization has 41427 authors who have published 83598 publications receiving 2911437 citations. The organization is also known as: Mizzou & Missouri-Columbia.

Phosphorylation of 1-Aminocyclopropane-1-Carboxylic Acid Synthase by MPK6, a Stress-Responsive Mitogen-Activated Protein Kinase, Induces Ethylene Biosynthesis in Arabidopsis

Abstract: Mitogen-activated protein kinases (MAPKs) are implicated in regulating plant growth, development, and response to the environment. However, the underlying mechanisms are unknown because of the lack of information about their substrates. Using a conditional gain-of-function transgenic system, we demonstrated that the activation of SIPK, a tobacco (Nicotiana tabacum) stress-responsive MAPK, induces the biosynthesis of ethylene. Here, we report that MPK6, the Arabidopsis thaliana ortholog of tobacco SIPK, is required for ethylene induction in this transgenic system. Furthermore, we found that selected isoforms of 1-aminocyclopropane-1-carboxylic acid synthase (ACS), the rate-limiting enzyme of ethylene biosynthesis, are substrates of MPK6. Phosphorylation of ACS2 and ACS6 by MPK6 leads to the accumulation of ACS protein and, thus, elevated levels of cellular ACS activity and ethylene production. Expression of ACS6DDD, a gain-of-function ACS6 mutant that mimics the phosphorylated form of ACS6, confers constitutive ethylene production and ethylene-induced phenotypes. Increasing numbers of stress stimuli have been shown to activate Arabidopsis MPK6 or its orthologs in other plant species. The identification of the first plant MAPK substrate in this report reveals one mechanism by which MPK6/SIPK regulates plant stress responses. Equally important, this study uncovers a signaling pathway that modulates the biosynthesis of ethylene, an important plant hormone, in plants under stress.

Relationships between crystal structure and magnetic properties in Nd 2 Fe 14 B

Abstract: Determination of the crystal structure of ${\mathrm{Nd}}_{2}$${\mathrm{Fe}}_{14}$B, a new ternary phase, is reported. It has recently been demonstrated that permanent magnets having large coercivities and energy products can be formed from this phase, underscoring its potential technological importance. We relate the crystal structure and intrinsic magnetic properties by considering analogies with previously known rare-earth---transition-metal materials.

Reconsidering happiness: the costs of distinguishing between hedonics and eudaimonia

Abstract: In recent years, well-being researchers have distinguished between eudaimonic happiness (e.g., meaning and purpose; taking part in activities that allow for the actualization of one's skills, talents, and potential) and hedonic happiness (e.g., high frequencies of positive affect, low frequencies of negative affect, and evaluating life as satisfying). Unfortunately, this distinction (rooted in philosophy) does not necessarily translate well to science. Among the problems of drawing too sharp a line between ‘types of happiness’ is the fact that eudaimonia is not well-defined and lacks consistent measurement. Moreover, empirical evidence currently suggests that hedonic and eudaimonic well-being overlap conceptually, and may represent psychological mechanisms that operate together. In this article, we outline the problems and costs of distinguishing between two types of happiness, and provide detailed recommendations for a research program on well-being with greater scientific precision. The purpose of life ...

Advances in testing the statistical significance of mediation effects.

Abstract: P. A. Frazier, A. P. Tix, and K. E. Barron (2004) highlighted a normal theory method popularized by R. M. Baron and D. A. Kenny (1986) for testing the statistical significance of indirect effects (i.e., mediator variables) in multiple regression contexts. However, simulation studies suggest that this method lacks statistical power relative to some other approaches. The authors describe an alternative developed by P. E. Shrout and N. Bolger (2002) based on bootstrap resampling methods. An example and step-by-step guide for performing bootstrap mediation analyses are provided. The test of joint significance is also briefly described as an alternative to both the normal theory and bootstrap methods. The relative advantages and disadvantages of each approach in terms of precision in estimating confidence intervals of indirect effects, Type I error, and Type II error are discussed.