Crystal structure of a lipid G protein-coupled receptor

The lyso-phospholipid sphingosine 1-phosphate modulates lymphocyte trafficking, endothelial development and integrity, heart rate, and vascular tone and maturation by activating G protein-coupled sphingosine 1-phosphate receptors. Here, we present the crystal structure of the sphingosine 1-phosphate receptor 1 fused to T4-lysozyme (S1P(1)-T4L) in complex with an antagonist sphingolipid mimic. Extracellular access to the binding pocket is occluded by the amino terminus and extracellular loops of the receptor. Access is gained by ligands entering laterally between helices I and VII within the transmembrane region of the receptor. This structure, along with mutagenesis, agonist structure-activity relationship data, and modeling, provides a detailed view of the molecular recognition and requirement for hydrophobic volume that activates S1P(1), resulting in the modulation of immune and stromal cell responses.     

Kernel morphometric traits in hexaploid wheat (Triticum aestivum L.) are modulated by intricate QTL × QTL and genotype × environment interactions

Wheat kernel size and shape influence its flour yield and market price. A hexaploid wheat population of 185 recombinant inbred lines was evaluated for five kernel morphometric traits namely, 1000-kernel weight, kernel length, width, length–width ratio and factor form density in two diverse agro-climatic regions in India in five to eight year–location combinations. Additive main effects and multiplicative interaction analysis revealed significant contributions from genotype (G) and genotype × environment (G × E) effects for these traits. Quantitative trait locus (QTL) analysis by composite interval mapping (CIM) was performed using a linkage map of 251 SSR markers and 59 QTLs distributed on 16 chromosomes were identified. The majority of the QTLs were located on the D genome (44.07%) and the homeologous chromosomes of Group 2 (38.98%). Stable QTLs detected in three or more year–location combinations were identified for four traits. Multi-trait CIM showed 10 chromosomal regions harboring putative pleiotropic loci. Complexity in the genetic effects was further revealed by QTL analysis based on mixed-linear model that indicated 19 QTLs with significant individual effects (main-effect QTLs) and 14 QTL × QTL interactions. Five of these nineteen main-effect QTLs and one of the fourteen QTL × QTL interactions showed environmental influence.     

Evaluation of Brewer's Waste as Partial Replacement of Fish Meal Protein in Nile Tilapia, Oreochromis niloticus, Diets

Abstract.— Brewer's waste is one of the promising protein source by-products for fish diets. A 10-wk feeding trial experiment involving five different diets with increasing levels of brewer's waste (32% crude protein) was carried out to evaluate the use of brewer's waste in tilapia diets in place of fish meal. Growth performance was compared against a control diet formulated to have similar composition to a typical commercial diet. Four experimental diets replaced successively 25, 50, 75, and 100% of the fish meal protein with brewer's waste. The diets were isonitrogenous and isocaloric. Results indicated that weight gain did not differ significantly ( P  > 0.05) with up to 50% replacement. Feed intake and utilization were depressed at high levels of brewer's waste. In addition, methionine of high replacement level diets was low. The results of the digestibility trial demonstrated that the brewer's waste used in this study has an apparent digestibility coefficient for protein of 70%. It was concluded that 50% of the fish meal protein in a typical commercial diet could be replaced with brewer's waste with no adverse effect on growth and feed utilization for tilapia.