Amiloride does not alter NaCl avoidance in Fischer-344 rats

Fischer-344 (F-344) rats differ from other common rat strains in that they fail to show any preference for NaCl at any concentration in two- bottle preference tests. Because 100 microM amiloride partially blocks the NaCl-evoked chorda tympani (CT) response in electrophysiological studies, we tested NaCl preference (0.068-0.273 M) in F-344 rats with and without 100 microM amiloride solution as the solvent. A third group was tested with unadulterated NaCl solutions following CT transection. Amiloride had no significant effect on the NaCl preference-aversion function, whereas CT transection significantly reduced NaCl avoidance. These results suggest that the amiloride-sensitive component of the NaCl response is not necessary for F-344 rats to display avoidance of NaCl, but the entire CT input is.      

Male secondary sexual structures and the systematics of the Thereus oppia species group (Lepidoptera,Lycaenidae, Eumaeini)

The Thereus oppia species group includes species with and without a scent pad, which is a histologically and morphologically characterized male secondary sexual structure on the dorsal surface of the forewing. To assess the hypothesis that these structures are lost evolutionarily, but not regained (Dollo’s Law), the taxonomy of this species group is revised. Thereus lomalarga sp. n., and Thereus brocki sp. n., are described. Diagnostic traits, especially male secondary structures, within the Thereus oppia species group are illustrated. Distributional and biological information is summarized for each species. Three species have been reared, and the caterpillars eat Loranthaceae. An inferred phylogeny is consistent with the hypothesis that scent pads in the Thereus oppia species group have been lost evolutionarily twice (in allopatry), and not re-gained.     

Using the longest significance run to estimate region-specific p-values in genetic association mapping studies

Background  

Association testing is a powerful tool for identifying disease susceptibility genes underlying complex diseases. Technological advances have yielded a dramatic increase in the density of available genetic markers, necessitating an increase in the number of association tests required for the analysis of disease susceptibility genes. As such, multiple-tests corrections have become a critical issue. However the conventional statistical corrections on locus-specific multiple tests usually result in lower power as the number of markers increases. Alternatively, we propose here the application of the longest significant run (LSR) method to estimate a region-specific p-value to provide an index for the most likely candidate region.     

The complement component C1s is the protease that accounts for cleavage of insulin-like growth factor-binding protein-5 in fibroblast medium

Cultured fibroblasts secrete an 88-kDa serine protease that cleaves insulin-like growth factor binding protein-5 (IGFBP-5). Because IGFBP-5 has been shown to regulate IGF-I actions, understanding the chemical identity and regulation of this protease is important for understanding how IGF-I stimulates anabolic functions. The protease was purified from human fibroblast-conditioned medium by hydrophobic interaction, lectin affinity, and heparin Sepharose affinity chromatography followed by SDS-polyacrylamide gel electrophoresis. An 88-kDa band was excised and digested with lysyl-endopeptidase. Sequencing of the high pressure liquid chromatography-purified peptides yielded the complement components C1r and C1s. To confirm that C1r/C1s accounted for the proteolytic activity in the medium, immunoaffinity chromatography was performed. Most of the protease activity adhered to the column, and the eluant was fully active in cleaving IGFBP-5. SDS-polyacrylamide gel electrophoresis with silver staining showed two bands, and IGFBP-5 zymography showed a single 88-kDa band. Amino acid sequencing confirmed that the 88-kDa band contained only C1r and C1s. C1r in the fibroblast medium underwent autoactivation, and the activated form cleaved C1s. C1s purified from the conditioned medium cleaved C(4), a naturally occurring substrate. The purified protease cleaved IGFBP-5 but had no activity against IGFBP-1 through -4. C1 inhibitor, a protein known to inhibit activated C1s, was shown to inhibit the cleavage of IGFBP-5 by the protease in the conditioned medium. In summary, human fibroblasts secrete C1r and C1s that actively cleave IGFBP-5. The findings define a mechanism for cleaving IGFBP-5 in the culture medium, thus allowing release of IGF-I to cell surface receptors.     

Activation Domain-dependent Degradation of Somatic Wee1 Kinase

Cell cycle progression is dependent upon coordinate regulation of kinase and proteolytic pathways. Inhibitors of cell cycle transitions are degraded to allow progression into the subsequent cell cycle phase. For example, the tyrosine kinase and Cdk1 inhibitor Wee1 is degraded during G₂ and mitosis to allow mitotic progression. Previous studies suggested that the N terminus of Wee1 directs Wee1 destruction. Using a chemical mutagenesis strategy, we report that multiple regions of Wee1 control its destruction. Most notably, we find that the activation domain of the Wee1 kinase is also required for its degradation. Mutations in this domain inhibit Wee1 degradation in somatic cell extracts and in cells without affecting the overall Wee1 structure or kinase activity. More broadly, these findings suggest that kinase activation domains may be previously unappreciated sites of recognition by the ubiquitin proteasome pathway.