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.

The role of Cdc42p GTPase-activating proteins in assembly of the septin ring in yeast.

Abstract: The septins are a conserved family of GTP-binding, filament-forming proteins. In the yeast Saccharomyces cerevisiae, the septins form a ring at the mother-bud neck that appears to function primarily by serving as a scaffold for the recruitment of other proteins to the neck, where they participate in cytokinesis and a variety of other processes. Formation of the septin ring depends on the Rho-type GTPase Cdc42p but appears to be independent of the actin cytoskeleton. In this study, we investigated further the mechanisms of septin-ring formation. Fluorescence-recovery-after-photobleaching (FRAP) experiments indicated that the initial septin structure at the presumptive bud site is labile (exchanges subunits freely) but that it is converted into a stable ring as the bud emerges. Mutants carrying the cdc42V36G allele or lacking two or all three of the known Cdc42p GTPase-activating proteins (GAPs: Bem3p, Rga1p, and Rga2p) could recruit the septins to the cell cortex but were blocked or delayed in forming a normal septin ring and had accompanying morphogenetic defects. These phenotypes were dramatically enhanced in mutants that were also defective in Cla4p or Gin4p, two protein kinases previously shown to be important for normal septin-ring formation. The Cdc42p GAPs colocalized with the septins both early and late in the cell cycle, and overexpression of the GAPs could suppress the septin-organization and morphogenetic defects of temperature-sensitive septin mutants. Taken together, the data suggest that formation of the mature septin ring is a process that consists of at least two distinguishable steps, recruitment of the septin proteins to the presumptive bud site and their assembly into the stable septin ring. Both steps appear to depend on Cdc42p, whereas the Cdc42p GAPs and the other proteins known to promote normal septin-ring formation appear to function in a partially redundant manner in the assembly step. In addition, because the eventual formation of a normal septin ring in a cdc42V36G or GAP mutant was invariably accompanied by a switch from an abnormally elongated to a more normal bud morphology distal to the ring, it appears that the septin ring plays a direct role in determining the pattern of bud growth.

A review of nitrogen isotopic alteration in marine sediments

Abstract: Key Points: Use of sedimentary nitrogen isotopes is examined; On average, sediment 15N/14N increases approx. 2 per mil during early burial; Isotopic alteration scales with water depth Abstract: Nitrogen isotopes are an important tool for evaluating past biogeochemical cycling from the paleoceanographic record. However, bulk sedimentary nitrogen isotope ratios, which can be determined routinely and at minimal cost, may be altered during burial and early sedimentary diagenesis, particularly outside of continental margin settings. The causes and detailed mechanisms of isotopic alteration are still under investigation. Case studies of the Mediterranean and South China Seas underscore the complexities of investigating isotopic alteration. In an effort to evaluate the evidence for alteration of the sedimentary N isotopic signal and try to quantify the net effect, we have compiled and compared data demonstrating alteration from the published literature. A >100 point comparison of sediment trap and surface sedimentary nitrogen isotope values demonstrates that, at sites located off of the continental margins, an increase in sediment 15N/14N occurs during early burial, likely at the seafloor. The extent of isotopic alteration appears to be a function of water depth. Depth-related differences in oxygen exposure time at the seafloor are likely the dominant control on the extent of N isotopic alteration. Moreover, the compiled data suggest that the degree of alteration is likely to be uniform through time at most sites so that bulk sedimentary isotope records likely provide a good means for evaluating relative changes in the global N cycle.

Comparison of laparoscopic ovariohysterectomy and ovariohysterectomy in dogs.

Abstract: Objectives— To evaluate technique, complication rates, postoperative pain scores, and clinical outcomes in dogs after laparoscopic ovariohysterectomy (LOVH) or traditional ovariohysterectomy (OVH). Study Design— Prospective clinical trial. Animals or Sample Population— Thirty-four intact female dogs, weighing 2.4–31 kg. Methods— LOVH (16 dogs) was performed by ligation of the uterus and ovaries with surgical wire, and then removal by an assisted laparoscopic technique. OVH was performed in 18 dogs. Subjective and objective pain scores were assigned at 0, 2, 8, and 24 hours. Surgical time, complications, and pain and incision scores were evaluated. Dogs were followed for up to 6 months. Results— The mean surgical time for LOVH (120 minutes; range, 47–175 minutes) was significantly longer than for OVH (69 minutes; range, 25–140 minutes). Significantly lower pain scores (subjective, in 2 of 10 categories; objective, in 8 of 10 categories) were identified with LOVH at 1 or more time periods. Surgical complications with LOVH were postoperative fever and anorexia (1 dog), minor splenic (3) or pedicle hemorrhage (4), intermittent vaginal hemorrhagic discharge (1), and suture reaction (3). Surgical complications with OVH were hemorrhage from an ovarian pedicle requiring reoperation (1 dog), dehiscence of the abdominal wall (1), and seroma (1). Anesthetic complications included hypotension in 8 OVH dogs and 1 LOVH dog, and hypothermia in 4 OVH and 9 LOVH dogs. The mean incision scores were lower for LOVH at all time periods. Conclusion— LOVH was performed successfully in young nonparous dogs >10 kg. Surgical time and complication rates were greater; however, LOVH postoperative pain scores were ≤OVH scores. Clinical Relevance— LOVH is a potentially safe surgical alternative to traditional OVH in dogs. Equipment cost and necessity for more than 1 surgeon may limit its usefulness in small animal practice.