Replication and fine mapping of asthma-associated loci in individuals of African ancestry

Asthma originates from genetic and environmental factors with about half the risk of disease attributable to heritable causes. Genome-wide association studies, mostly in populations of European ancestry, have identified numerous asthma-associated single nucleotide polymorphisms (SNPs). Studies in populations with diverse ancestries allow both for identification of robust associations that replicate across ethnic groups and for improved resolution of associated loci due to different patterns of linkage disequilibrium between ethnic groups. Here we report on an analysis of 745 African-American subjects with asthma and 3,238 African-American control subjects from the Candidate Gene Association Resource (CARe) Consortium, including analysis of SNPs imputed using 1,000 Genomes reference panels and adjustment for local ancestry. We show strong evidence that variation near RAD50/IL13, implicated in studies of European ancestry individuals, replicates in individuals largely of African ancestry. Fine mapping in African ancestry populations also refined the variants of interest for this association. We also provide strong or nominal evidence of replication at loci near ORMDL3/GSDMB, IL1RL1/IL18R1, and 10p14, all previously associated with asthma in European or Japanese populations, but not at the PYHIN1 locus previously reported in studies of African-American samples. These results improve the understanding of asthma genetics and further demonstrate the utility of genetic studies in populations other than those of largely European ancestry.     

Effect of modification of histidine residues on organization of the pigment--protein complexes of chromatium minutissimum

The effect of diethyl pyrocarbonate on chromatophores and isolated pigment--protein complexes of Chromatium minutissimum was studied. It is shown that modification of histidine residues results in the destruction of the core antenna LHI (B880) and in a spectral shift from 850 to 830 nm in the peripheral antenna LHII (B800-850). In the purple sulfur bacterium Chromatium minutissimum the pigment--protein complexes B800-B850 (peripheral antenna, LHII) and B880 (core antenna, LHI) collect and transmit the absorbed light energy to the reaction centers. The composition of pigments and proteins as well as primary structure of the majority of polypeptides in both types of complexes from various photosynthetic bacteria have been determined.     

Effect of the pyridoindole antioxidant stobadine on the cardiac Na(+),K(+)-ATPase in rats with streptozotocin-induced diabetes

In the present study we examined the effect of dietary supplementation with the pyridoindole antioxidant stobadine on functional properties of the cardiac Na(+),K(+)-ATPase in diabetic rats. Diabetes lasting sixteen weeks which was induced by a single i.v. dose of streptozotocin (55 mg x kg(-1)) was followed by decrease in the enzyme activity. Evaluation of kinetic parameters revealed a statistically significant decrease in the maximum velocity (Vmax) (32% for ATP-activation, 33% for Na(+)-activation), indicating a diabetes-induced diminution of the number of active enzyme molecules in cardiac sarcolemma. The ATP-binding properties of the enzyme were not affected by diabetes as suggested by statistically insignificant changes in the value of Michaelis-Menten constant, K(M (ATP)). On the other hand, the affinity to sodium decreased as suggested by 54% increase in the K(M (Na+)) value. This impairment in the affinity of the Na(+)-binding site together with decreased number of active Na(+),K(+)-ATPase molecules are probably responsible for the deteriorated enzyme function in hearts of diabetic animals. Administration of stobadine to diabetic rats dramatically improved the function of cardiac Na(+),K(+)-ATPase with regard to Na(+)-handling, as documented by statistically significant elevation of Vmax by 66 and 47% decrease in K(M (Na+)). Our data suggest that stobadine may prevent the diabetes-induced deterioration of cardiac Na(+),K(+)-ATPase, thus enabling to preserve its normal function in regulation of intracellular homeostasis of Na(+) and K(+) ions.