Oklahoma State University–Stillwater

About: Oklahoma State University–Stillwater is a education organization based out in Stillwater, Oklahoma, United States. It is known for research contribution in the topics: Population & Large Hadron Collider. The organization has 18267 authors who have published 36743 publications receiving 1107500 citations. The organization is also known as: Oklahoma State University & OKState.

Bacterial community structure and diversity in a century-old manure-treated agroecosystem.

Abstract: Changes in soil microbial community structure and diversity may reflect environmental impact. We examined 16S rRNA gene fingerprints of bacterial communities in six agroecosystems by PCR amplification and denaturing gradient gel electrophoresis (PCR-DGGE) separation. These soils were treated with manure for over a century or different fertilizers for over 70 years. Bacterial community structure and diversity were affected by soil management practices, as evidenced by changes in the PCR-DGGE banding patterns. Bacterial community structure in the manure-treated soil was more closely related to the structure in the untreated soil than that in soils treated with inorganic fertilizers. Lime treatment had little effect on bacterial community structure. Soils treated with P and N-P had bacterial community structures more closely related to each other than to those of soils given other treatments. Among the soils tested, a significantly higher number of bacterial ribotypes and a more even distribution of the bacterial community existed in the manure-treated soil. Of the 99 clones obtained from the soil treated with manure for over a century, two (both Pseudomonas spp.) exhibited 100% similarity to sequences in the GenBank database. Two of the clones were possible chimeras. Based on similarity matching, the remaining 97 clones formed six major clusters. Fifty-six out of 97 were assigned taxonomic units which grouped into five major taxa: α-, β-, and γ-Proteobacteria (36 clones), Acidobacteria (16 clones), Bacteroidetes (2 clones), Nitrospirae (1 clone), and Firmicutes (1 clone). Forty-one clones remained unclassified. Results from this study suggested that bacterial community structure was closely related to agroecosystem management practices conducted for over 70 years.

A FUSCA gene of Arabidopsis encodes a novel protein essential for plant development.

Abstract: Arabidopsis fusca mutants display striking purple coloration due to anthocyanin accumulation in their cotyledons. We describe six recessive fusca mutants isolated from Agrobacterium-transformed Arabidopsis families. These mutants first become defective during embryogenesis and exhibit limited seedling development. Double mutant constructs revealed that developmental defects were not simply a consequence of anthocyanin accumulation. fusca seedlings showed altered responses to several environmental and endogenous factors. Allelism tests established that three fusca loci are represented by mutants previously described as defective in light-regulated responses. To study the molecular basis of the fusca phenotype, we cloned the FUS6 gene. FUS6 encodes a novel protein that is hydrophilic, alpha-helical, and contains potential protein kinase C phosphorylation sites. The FUSCA proteins appear to act in a network of signal transduction pathways critical for plant development.

Piezoelectric-on-Silicon Lateral Bulk Acoustic Wave Micromechanical Resonators

Abstract: This paper reports on the design, fabrication, and characterization of piezoelectrically-transduced micromechanical single-crystal-silicon resonators operating in their lateral bulk acoustic modes to address the need for high-Q microelectronic-integrable frequency-selective components. A simple electromechanical model for optimizing performance is presented. For verification, resonators were fabricated on 5-mum-thick silicon-on- insulator substrates and use a 0.3-mum zinc oxide film for transduction. A bulk acoustic mode was observed from a 240 mum times 40 mum resonator with a 600-Omega impedance (Q=3400 at P=1 atm) at 90 MHz. A linear resonator absorbed power of -0.5 dBm and an output current of 1.3 mA rms were measured. The same device also exhibited a Q of 12 000 in its fundamental extensional mode at a pressure of 5 torr.

Patterns and causes of incongruence between plastid and nuclear Senecioneae (Asteraceae) phylogenies

Abstract: One of the longstanding questions in phylogenetic systematics is how to address incongruence among phylogenies obtained from multiple markers and how to determine the causes. This study presents a detailed analysis of incongruent patterns between plastid and ITS/ETS phylogenies of Tribe Senecioneae (Asteraceae). This approach revealed widespread and strongly supported incongruence, which complicates conclusions about evolutionary relationships at all taxonomic levels. The patterns of incongruence that were resolved suggest that incomplete lineage sorting (ILS) and/or ancient hybridization are the most likely explanations. These phenomena are, however, extremely difficult to distinguish because they may result in similar phylogenetic patterns. We present a novel approach to evaluate whether ILS can be excluded as an explanation for incongruent patterns. This coalescence-based method uses molecular dating estimates of the duration of the putative ILS events to determine if invoking ILS as an explanation for incongruence would require unrealistically high effective population sizes. For four of the incongruent patterns identified within the Senecioneae, this approach indicates that ILS cannot be invoked to explain the observed incongruence. Alternatively, these patterns are more realistically explained by ancient hybridization events.