Michigan State University

About: Michigan State University is a education organization based out in East Lansing, Michigan, United States. It is known for research contribution in the topics: Population & Poison control. The organization has 60109 authors who have published 137074 publications receiving 5633022 citations. The organization is also known as: MSU & Michigan State.

FeII/alpha-ketoglutarate-dependent hydroxylases and related enzymes.

Abstract: FeII/alpha-ketoglutarate (alphaKG)-dependent hydroxylases catalyze an amazing diversity of reactions that result in protein side-chain modifications, repair of alkylated DNA/RNA, biosynthesis of antibiotics and plant products, metabolism related to lipids, and biodegradation of a variety of compounds. These enzymes possess a beta-strand "jellyroll" structural fold that contains three metal-binding ligands found in a His1-X-Asp/Glu-Xn-His2 motif. The cosubstrate, alphaKG, chelates FeII using its C-2 keto group (binding opposite the Asp/Glu residue) and C-1 carboxylate (coordinating opposite either His1 or His2). Oxidative decomposition of alphaKG forms CO2 plus succinate and leads to the generation of an FeIV-oxo or other activated oxygen species that hydroxylate the primary substrate. The reactive oxygen species displays alternate reactivity in related enzymes that catalyze desaturations, ring expansions, or ring closures. Other enzymes resemble the FeII/alphaKG-dependent hydroxylases in terms of protein structure or chemical mechanism but do not utilize alphaKG as a substrate. This review describes the reactions catalyzed by this superfamily of enzymes, highlights key active site features revealed by structural studies, and summarizes results from spectroscopic and other approaches that provide insights into the chemical mechanisms.

The caregiver reaction assessment (CRA) for caregivers to persons with chronic physical and mental impairments

Abstract: The development and testing of a multidimensional instrument to assess the reactions of family members caring for elderly persons with physical impairments, Alzheimer's disease, and cancer is reported Forty items were administered to a sample of 377 caregivers of persons with physical impairments and Alzheimer's disease Five dimensions of caregivers' reactions were identified through exploratory factor analysis Using confirmatory factor analysis on an independent sample (N = 377), these dimensions were tested for factorial invariance across spouse and nonspouse caregivers and between caregivers of persons with cancer and those caring for persons with Alzheimer's disease The subscales also had a high level of factorial invariance across a three-wave panel study (N = 185) The subscales appeared consistent with first order tests of construct validity

What’s My Style? The Influence of Top Managers on Voluntary Corporate Financial Disclosure

Abstract: Prior research in finance and accounting generally posits a limited role for idiosyncratic manager-specific attributes in explaining accounting and disclosure choices. In contrast, upper echelons theory, originating in the strategic management literature, suggests that differences among individuals can affect corporate outcomes. Extant research in voluntary disclosure follows the traditional financial economics perspective, yet even the most comprehensive empirical models leave most of the cross-sectional variation in disclosure unexplained. This prompts us to investigate whether these models are missing a major component: Do idiosyncratic differences among individual managers play a significant incremental role in voluntary corporate financial disclosure? We build a data set that tracks managers over time, which allows us to isolate manager-specific fixed effects after controlling for firm effects. We find that top executives do exhibit unique individual-specific and economically significant disclosure styles. That is, our evidence suggests that individual managers significantly influence attributes of their firms' voluntary disclosures, even after controlling for techno-economic determinants of disclosure identified in prior research, and firm- and time-specific effects. The collective magnitude of these manager-specific fixed effects is large: Manager-specific effects explain roughly as much or more of the variation in disclosure as the known techno-economic determinants combined. We then investigate whether managers' unique fixed effects are associated with observable characteristics of their own personal backgrounds. We find that managers promoted from finance, accounting, and legal career tracks, managers born before World War II, and managers holding MBAs tend to exhibit more conservative disclosure styles. These associations between our estimates of managers' fixed effects and distinctive (permanent) characteristics of their own personal backgrounds provide evidence confirming that our estimated manager fixed effects capture systematic long-lived differences in managers' unique disclosure styles. Our results suggest that individual-specific effects play an important - yet heretofore largely unexplored - role in voluntary financial disclosure. Further investigation of the role unique individual characteristics play in explaining corporate financial reporting is potentially a fruitful direction for future research.

Dormancy contributes to the maintenance of microbial diversity

Abstract: Dormancy is a bet-hedging strategy used by a variety of organisms to overcome unfavorable environmental conditions. By entering a reversible state of low metabolic activity, dormant individuals become members of a seed bank, which can determine community dynamics in future generations. Although microbiologists have documented dormancy in both clinical and natural settings, the importance of seed banks for the diversity and functioning of microbial communities remains untested. Here, we develop a theoretical model demonstrating that microbial communities are structured by environmental cues that trigger dormancy. A molecular survey of lake ecosystems revealed that dormancy plays a more important role in shaping bacterial communities than eukaryotic microbial communities. The proportion of dormant bacteria was relatively low in productive ecosystems but accounted for up to 40% of taxon richness in nutrient-poor systems. Our simulations and empirical data suggest that regional environmental cues and dormancy synchronize the composition of active communities across the landscape while decoupling active microbes from the total community at local scales. Furthermore, we observed that rare bacterial taxa were disproportionately active relative to common bacterial taxa, suggesting that microbial rank-abundance curves are more dynamic than previously considered. We propose that repeated transitions to and from the seed bank may help maintain the high levels of microbial biodiversity that are observed in nearly all ecosystems.