Effects of inhibiting antioxidant pathways on cellular hydrogen sulfide and polysulfide metabolism

Elaborate antioxidant pathways have evolved to minimize the threat of excessive reactive oxygen species (ROS) and to regulate ROS as signaling entities. ROS are chemically and functionally similar to reactive sulfur species (RSS) and both ROS and RSS have been shown to be metabolized by the antioxidant enzymes, superoxide dismutase and catalase. Here we use fluorophores to examine the effects of a variety of inhibitors of antioxidant pathways on metabolism of two important RSS, hydrogen sulfide (H2S with AzMC) and polysulfides (H2Sn, where n = 2–7, with SSP4) in HEK293 cells. Cells were exposed to inhibitors for up to 5 days in normoxia (21% O2) and hypoxia (5% O2), conditions also known to affect ROS production. Decreasing intracellular glutathione (GSH) with l-buthionine-sulfoximine (BSO) or diethyl maleate (DEM) decreased H2S production for 5 days but did not affect H2Sn. The glutathione reductase inhibitor, auranofin, initially decreased H2S and H2Sn but after two days H2Sn increased over controls. Inhibition of peroxiredoxins with conoidin A decreased H2S and increased H2Sn, whereas the glutathione peroxidase inhibitor, tiopronin, increased H2S. Aminoadipic acid, an inhibitor of cystine uptake did not affect either H2S or H2Sn. In buffer, the glutathione reductase and thioredoxin reductase inhibitor, 2-AAPA, the glutathione peroxidase mimetic, ebselen, and tiopronin variously reacted directly with AzMC and SSP4, reacted with H2S and H2S2, or optically interfered with AzMC or SSP4 fluorescence. Collectively these results show that antioxidant inhibitors, generally known for their ability to increase cellular ROS, have various effects on cellular RSS. These findings suggest that the inhibitors may affect cellular sulfur metabolism pathways that are not related to ROS production and in some instances they may directly affect RSS or the methods used to measure them. They also illustrate the importance of carefully evaluating RSS metabolism when biologically or pharmacologically attempting to manipulate ROS

Effects of squash leaf trichome exudates and honey on adult feeding, survival, and fecundity of the squash bug (Heteroptera: Coreidae) egg parasitoid Gryon pennsylvanicum (Hymenoptera: Scelionidae)

Citation: Olson, D., & Nechols, J. Effects of Squash Leaf Trichome Exudates and Honey on Adult Feeding, Survival, and Fecundity of the Squash Bug (Heteroptera: Coreidae) Egg Parasitoid Gryon pennsylvanicum (Hymenoptera: Scelionidae). Environmental Entomology, 24(2), 454-458. https://doi.org/10.1093/ee/24.2.454A laboratory experiment was conducted to determine whether leaf exudates could be used as a source of adult nutrition for the squash bug, Auasa tristis (De Geer), egg parasitoid, Gryon pennsylvanicum (Ashmead), and to compare adult and progeny fitness traits when female Wasps were provided with squash leaves, a standard honey diet, a combination of leaves and honey, or water only Results showed that fecundity, progeny developmental rates, and progeny survival did not differ significantly when females were exposed to different dietary sources. Adult longevity was shorter on squash leaves without honey than on leaves with honey or the honey-only diet. However, reproductive fitness was not reduced because oviposition had been completed before death of the adult females. When only water was provided, parasitoid females lived only a few days. Observations showed that squash leaves have two kinds of trichomes (hair-like and peg-like), both of which produce droplets that are fed on by both sexes of G. pennsylvanicum. Nutrient analyses revealed that exudates from the hair-like trichomes are composed predominantly of monosaccharides (mainly glucose and galactose), and that the peg-like trichomes produce glucose and some protein. Thus, these trichomes appear to serve as extrafloral nectaries and may provide an important energy source for augmentatively released G. pennsylvanicum

Unified model of loop quantum gravity and matter

We reconsider the unified model of gravitation and Yang--Mills interactions proposed by Chakraborty and Peld\'an, in the light of recent formal developments in loop quantum gravity. In particular, we show that one can promote the Hamiltonian constraint of the unified model to a well defined anomaly-free quantum operator using the techniques introduced by Thiemann, at least for the Euclidean theory. The Lorentzian version of the model can be consistently constructed, but at the moment appears to yield a correct weak field theory only under restrictive assumptions, and its quantization appears problematic.Comment: 4 pages, dedicated to Michael P. Ryan on the occasion of his sixtieth birthda

Investigation of solid state traveling-wave- amplifier techniques for future satellite applications Quarterly progress report no. 4, 1 Mar. - 30 Jun. 1965

Solid state traveling wave amplifier techniques for satellite application

Provisions and Potential Impacts of the Average Crop Revenue Election (ACRE) Program

Replaced with revised version of paper 11/24/08.Agricultural and Food Policy, Crop Production/Industries,

Fluctuating Topological Defects in 2D Liquids: Heterogeneous Motion and Noise

We measure the defect density as a function of time at different temperatures in simulations of a two dimensional system of interacting particles. Just above the solid to liquid transition temperature, the power spectrum of the defect fluctuations shows a 1/f signature, which crosses over to a white noise signature at higher temperatures. When 1/f noise is present, the 5-7 defects predominately form string like structures, and the particle trajectories show a 1D correlated motion that follows the defect strings. At higher temperatures this heterogeneous motion is lost. We demonstrate this heterogeneity both in systems interacting with a short ranged screened Coulomb interaction, as well as in systems with a long range logarithmic interaction between the particles.Comment: 4 pages, 5 postscript figure

Investigation of solid state traveling-wave amplifier techniques for future satellite applications monthly progress report no. 5, 1 - 31 jan. 1965

Solid state traveling wave amplifier techniques for satellite application

Estimates of Minnesota Farm-Level Crop Commodity Payments under New House Framework

The objective of this study is to compare commodity payments under current Federal farm policy with the previous Senate and Administration proposals and the recently released “2008 Farm Bill Conference: House Agriculture Committee-Developed Concept for a Farm Bill Spending Framework.” Projections of crop revenue and government payments are made using historical yield data for each example farm, the county, and the nation; historical price data; and statistical distributions and relationships of these yields and prices. Using 2007 FAPRI price projections (which are closer to the prices expected in the next few years when a new farm bill will be in force), expected Total Government Payments (TGP) are almost entirely attributed to the fixed direct payments under all these proposals. Since commodity prices are so far above their “target levels” the possibility of a counter cyclical price or revenue payment or a loan deficiency payment is highly unlikely. TGP under the alternative policies follows a similar pattern on the example corn and soybean farms and a slightly different but fairly consistent pattern for the example wheat and soybean farms. For the corn and soybean example farms in southern Minnesota, the HB-RCCP and USDA proposals generate very similar levels of TGPs compared to current policy. HB-RCCP provides a slightly higher expected TGP than CP for all example farms except for one and higher TGP than USDA for all farms. ACR is estimated to provide lower TGP for all example corn and soybean farms. For the example wheat and soybean farms in northwest Minnesota, the results are mixed. Compared to the other three proposals, ACR provides higher TGP for 2 of the 6 example farms. Each of the proposals does reduce risk as measured by CV. We note ACR is not quite as efficient at risk reduction except for two wheat/soybean farms in northwest Minnesota.Farm Management,

New GOES satellite synchronized time code generation

The TRAK Systems' GOES Satellite Synchronized Time Code Generator is described. TRAK Systems has developed this timing instrument to supply improved accuracy over most existing GOES receiver clocks. A classical time code generator is integrated with a GOES receiver