Thermodynamic and structural analysis of peptide- and allele-dependent properties of two HLA-B27 subtypes exhibiting differential disease association

Selected HLA-B27 subtypes are associated with spondyloarthropathies, but the underlying mechanism is not understood. To explain this association in molecular terms, a comparison of peptide-dependent dynamic and structural properties of the differentially disease-associated subtypes HLA-B*2705 and HLA-B*2709 was carried out. These molecules differ only by a single amino acid at the floor of the peptide binding groove. The thermostabilities of a series of HLA-B27 molecules complexed with nonameric and decameric peptides were determined and revealed substantial differences depending on the subtype as well as the residues at the termini of the peptides. In addition we present the crystal structure of the B*2709 subtype complexed with a decameric peptide. This structure provides an explanation for the preference of HLA-B27 for a peptide with an N-terminal arginine as secondary anchor and the lack of preference for tyrosine as peptide C terminus in B*2709. The data show that differences in thermodynamic properties between peptide-complexed HLA-B27 subtypes are correlated with a variety of structural properties

Different Grass Availabilities of Tropical Pasture on Performances and Carcasses of Lambs

This study aimed to identify the best green-leaf offerings of Urochloa brizantha cv. Marandu for pasture-finished lambs receiving protein-energy supplementation at the rate of 1.6% of their body weights (BW). The animals were assigned into four treatments, which consisted of varied green-leaf offerings, namely, 105, 90, 75, or 60 g of dry matter/kg of body weight (BW). Sixty-eight contemporary Texel × mixed-breed lambs with an average initial BW of 22.6 kg were used over two years of experiment. The experiment was set up in a completely randomized design, the data were evaluated by analysis of variance and the means were compared by Tukey’s test at the 0.05 significance level. There was no significant effect of year neither interaction of year with green-leaf offer. There were significant effects of leaf offer on dry matter intake (DMI) with behavior of positively linear (p<0.05). There were significant effects of green-leaf offer on final BW and average daily gain, and lambs receiving of 75 g/kg green-leaf offer showed the highest ADG (179 g/d). There were no significant differences in the carcass, meat, and primal cuts between the groups of lambs receiving different herbage offerings. There were significant effects of leaf offer on slaughter weight, hot carcass weight, and subcutaneous fat thickness. Lambs receiving of 75 g/kg leaf offer showed the highest SFT (5.8 mm). Slaughter weight and hot carcass weight averaged 41.52 kg and 20.07 kg, respectively. We recommend the treatment with leaves offer of 75 g/kg BW of Marandu pasture for the finishing of lambs supplemented at 1.6% of BW