Meridional variations in contrast sensitivity for human subjects

Meridional variations in contrast sensitivity for human subject

Kirkwood Community College Terminal Sire Demonstration Project

Nine different terminal sire lines were a Yorkshire/landrace sow herd at the Kirkwood Community College over a 30-month time span to determine production and economic merits of different sire lines. 1 The lowest backfat of the progeny came from the Danbred sire line. Premier T-Max sire line gave the progeny the largest loin muscle area and the highest per cent lean. The Waldo Duroc sire line produces the lowest selling age, lowest days to 250 lb., highest terminal sire index and highest overall economic value. The data indicate all the mated sire lines can provide positive contributions to commercial swine production. The use of a particular sire line within a herd will depend on the compliments of the sow herd, the desired progeny results, and the anticipated marketing outlet

Peer Sexual Harassment and Peer Violence Among Adolescents in Johanesburg and Chicago

In this comparison study of peer sexual harassment and peer violence in South African and US schools, the roles of gender and power in the experience, perpetration, and reaction to peer sexual harassment, physical violence and sexual violence are described for 208 South African students and 224 US students age 16-18

Natively oxidized amino acid residues in the spinach PS I-LHC I supercomplex

© 2020, Springer Nature B.V. Reactive oxygen species (ROS) production is an unavoidable byproduct of electron transport under aerobic conditions. Photosystem II (PS II), the cytochrome b6/f complex and Photosystem I (PS I) are all demonstrated sources of ROS. It has been proposed that PS I produces substantial levels of a variety of ROS including O2.−, 1O2, H2O2 and, possibly, •OH; however, the site(s) of ROS production within PS I has been the subject of significant debate. We hypothesize that amino acid residues close to the sites of ROS generation will be more susceptible to oxidative modification than distant residues. In this study, we have identified oxidized amino acid residues in spinach PS I which was isolated from field-grown spinach. The modified residues were identified by high-resolution tandem mass spectrometry. As expected, many of the modified residues lie on the surface of the complex. However, a well-defined group of oxidized residues, both buried and surface-exposed, lead from the chl a’ of P700 to the surface of PS I. These residues (PsaB: 609F, 611E, 617M, 619W, 620L, and PsaF: 139L, 142A,143D) may identify a preferred route for ROS, probably 1O2, to egress the complex from the vicinity of P700. Additionally, two buried residues located in close proximity to A1B (PsaB:712H and 714S) were modified, which appears consistent with A1B being a source of O2.−. Surprisingly, no oxidatively modified residues were identified in close proximity to the 4Fe–FS clusters FX, FA or FB. These cofactors had been identified as principal targets for ROS damage in the photosystem. Finally, a large number of residues located in the hydrophobic cores of Lhca1–Lhca4 are oxidatively modified. These appear to be the result of 1O2 production by the distal antennae for the photosystem

Dynamically controlled crystal growth system

Crystal growth can be initiated and controlled by dynamically controlled vapor diffusion or temperature change. In one aspect, the present invention uses a precisely controlled vapor diffusion approach to monitor and control protein crystal growth. The system utilizes a humidity sensor and various interfaces under computer control to effect virtually any evaporation rate from a number of different growth solutions simultaneously by means of an evaporative gas flow. A static laser light scattering sensor can be used to detect aggregation events and trigger a change in the evaporation rate for a growth solution. A control/follower configuration can be used to actively monitor one chamber and accurately control replicate chambers relative to the control chamber. In a second aspect, the invention exploits the varying solubility of proteins versus temperature to control the growth of protein crystals. This system contains miniature thermoelectric devices under microcomputer control that change temperature as needed to grow crystals of a given protein. Complex temperature ramps are possible using this approach. A static laser light scattering probe also can be used in this system as a non-invasive probe for detection of aggregation events. The automated dynamic control system provides systematic and predictable responses with regard to crystal size. These systems can be used for microgravity crystallization projects, for example in a space shuttle, and for crystallization work under terrestial conditions. The present invention is particularly useful for macromolecular crystallization, e.g. for proteins, polypeptides, nucleic acids, viruses and virus particles

Natively oxidized amino acid residues in the spinach cytochrome b\u3csub\u3e6\u3c/sub\u3e f complex

© 2018, Springer Science+Business Media B.V., part of Springer Nature. The cytochrome b6f complex of oxygenic photosynthesis produces substantial levels of reactive oxygen species (ROS). It has been observed that the ROS production rate by b6f is 10–20 fold higher than that observed for the analogous respiratory cytochrome bc1 complex. The types of ROS produced (O2•−, 1O2, and, possibly, H2O2) and the site(s) of ROS production within the b6f complex have been the subject of some debate. Proposed sources of ROS have included the heme bp, PQp•− (possible sources for O2•−), the Rieske iron–sulfur cluster (possible source of O2•− and/or 1O2), Chl a (possible source of 1O2), and heme cn (possible source of O2•− and/or H2O2). Our working hypothesis is that amino acid residues proximal to the ROS production sites will be more susceptible to oxidative modification than distant residues. In the current study, we have identified natively oxidized amino acid residues in the subunits of the spinach cytochrome b6f complex. The oxidized residues were identified by tandem mass spectrometry using the MassMatrix Program. Our results indicate that numerous residues, principally localized near p-side cofactors and Chl a, were oxidatively modified. We hypothesize that these sites are sources for ROS generation in the spinach cytochrome b6f complex

Identification of oxidized amino acid residues in the vicinity of the Mn \u3csub\u3e4\u3c/sub\u3eCaO \u3csub\u3e5\u3c/sub\u3e cluster of photosystem II: Implications for the identification of oxygen channels within the photosystem

As a light-driven water-plastoquinone oxidoreductase, Photosystem II produces molecular oxygen as an enzymatic product. Additionally, under a variety of stress conditions, reactive oxygen species are produced at or near the active site for oxygen evolution. In this study, Fourier-transform ion cyclotron resonance mass spectrometry was used to identify oxidized amino acid residues located in several core Photosystem II proteins (D1, D2, CP43, and CP47) isolated from spinach Photosystem II membranes. While the majority of these oxidized residues (81%) are located on the oxygenated solvent-exposed surface of the complex, several residues on the CP43 protein ( 354E, 355T, 356M, and 357R) which are in close proximity (\u3c15 \u3eÅ) to the Mn 4CaO 5 active site are also modified. These residues appear to be associated with putative oxygen/reactive oxygen species exit channel(s) in the photosystem. These results are discussed within the context of a number of computational studies which have identified putative oxygen channels within the photosystem. © 2012 American Chemical Society

Phosphorus and Dairy/Beef Nutrition

Phosphorus (P), a required nutrient for all livestock, has numerous essential physiological functions in the body that include energy transfer (ATP), structure of bone, teeth, and membranes, and buffering pH changes in the rumen (salivary phosphate). Ruminants use a larger proportion of dietary P than nonruminants because rumen microbes produce phytase, the enzyme that hydrolyzes P from phytate. The majority of P in most grains is in phytate form, a P form largely unavailable to swine and poultry