Angiotensinase activity in hypothalamus and pituitary of hypothyroid, euthyroid and hyperthyroid adult male rats.

A local renin-angiotensin system (RAS) that may be involved in their regulatory functions has been identified in hypothalamus and pituitary. Altered thyroid status induces modifications in the secretory function of hypothalamus and pituitary. However, few studies have analyzed the role of the RAS in hypothalamus and, to our knowledge, there is no data on the pituitary RAS during thyroid dysfunction. In the present study, angiotensinase activities (glutamyl, aspartyl and alanyl aminopeptidase: GluAP, AspAP and AlaAP, respectively) were studied in hypothalamus and in the anterior and posterior lobes of pituitary of euthyroid, hypothyroid and hyperthyroid adult male rats. In the anterior pituitary, compared with euthyroid and hyperthyroid rats, hypothyroid animals showed a highly significant increase of GluAP and AspAP activities; the percentage increase in GluAP was markedly higher than the percentage increase in AspAP. This suggests an increased metabolism of angiotensin (Ang) I and Ang II to des-Asp 1-Ang I and Ang III, respectively. We also observed an increase of Ang III-degrading activity (AlaAP) in the hypothalamus of hyperthyroid rats in soluble fraction. Increased Ang I and Ang II metabolism in the anterior pituitary of hypothyroid rats and increased metabolism of Ang III in the hypothalamus of hyperthyroid animals may be related to alterations in the secretory function of hypothalamus and pituitary in these thyroid dysfunctions.     

Two new species and new records for Pteris (Pteridaceae) from Colombia

A systematic review of the Colombian species of the tribe Pterideae (Pteridaceae) resulted in the discovery of two new species ofPteris:P. muricatopedata andP. albertiae, both in the Deflexa group. Two species are reported for the first time from Colombia:P. bakeri C. Chr. andP. lechleri Mett.     

Cross-strand side-chain interactions versus turn conformation in beta-hairpins.

A series of designed peptides has been analyzed by 1H-NMR spectroscopy in order to investigate the influence of cross-strand side-chain interactions in beta-hairpin formation. The peptides differ in the N-terminal residues of a previously designed linear decapeptide that folds in aqueous solution into two interconverting beta-hairpin conformations, one with a type I turn (beta-hairpin 4:4) and the other with a type I + G1 beta-bulge turn (beta-hairpin 3:5). Analysis of the conformational behavior of the peptides studied here demonstrates three favorable and two unfavorable cross-strand side-chain interactions for beta-hairpin formation. These results are in agreement with statistical data on side-chain interactions in protein beta-sheets. All the peptides in this study form significant populations of the beta-hairpin 3:5, but only some of them also adopt the beta-hairpin 4:4. The formation of beta-hairpin 4:4 requires the presence of at least two favorable cross-strand interactions, whereas beta-hairpin 3:5 seems to be less susceptible to side-chain interactions. A protein database analysis of beta-hairpins 3:5 and beta-hairpins 4:4 indicates that the former occur more frequently than the latter. In both peptides and proteins, beta-hairpins 3:5 have a larger right-handed twist than beta-hairpins 4:4, so that a factor contributing to the higher stability of beta-hairpin 3:5 relative to beta-hairpin 4:4 is due to an appropriate backbone conformation of the type I + G1 beta-bulge turn toward the right-handed twist usually observed in protein beta-sheets. In contrast, as suggested previously, backbone geometry of the type I turn is not adequate for the right-handed twist. Because analysis of buried hydrophobic surface areas on protein beta-hairpins reveals that beta-hairpins 3:5 bury more hydrophobic surface area than beta-hairpins 4:4, we suggest that the right-handed twist observed in beta-hairpin 3:5 allows a better packing of side chains and that this may also contribute to its higher intrinsic stability.     

Airborne grass pollen in Granada (Spain)

We have carried out a study on the annual and daily pollen concentrations from Gramineae over four consecutive years in the atmosphere of Granada (Spain). Samples of pollen grains were collected by the volumetric method with the aid of a Burkard sporetrap. Gramineae, according both to their high sensitizing capacity and to data from allergologists, are responsible for many pollinoses diagnosed in this area. In this work, daily pollen levels from April to July are monitored and the variations identified are interpreted in relation to meteorological conditions. Results indicated that the highest airborne concentrations of Gramineae pollen were found in May and June, although the beginning and intensity of pollination have been variable during these 4 years.     

The poor health of deep-water species in the context of fishing activity and a warming climate: will populations of Molva species rebuild or collapse?

Many deep-water fish populations, being K-selected species, have little resilience to overexploitation and may be at serious risk of depletion as a consequence. Sea warming represents an additional threat. In this study, the condition, or health, of several populations of common ling (Molva molva), blue ling (Molva dypterygia) and Mediterranean or Spanish ling (Molva macrophthalma) inhabiting different areas in the North Atlantic and the Mediterranean was evaluated, to shed light on the challenges these deep-water species are facing in the context of fishing activity and a warming climate. The data on the condition of Molva populations which are analysed here have been complemented with data on abundance and, for the southernmost species (Mediterranean ling), with two other health indicators (parasitism and hepato-somatic index). Despite some exceptions (e.g., common ling in Icelandic waters), this study shows that the condition of many populations of Molva species in the northeastern Atlantic and the Mediterranean Sea has worsened, a trend which, in recent decades, has usually been found to be accompanied by a decline in their abundance. In addition, the poor health status of most populations of common ling, blue ling and Mediterranean ling considered in this analysis points to a lower sustainability of these populations in the future. Overall, the health status and abundance of Molva populations in the northeastern Atlantic and the Mediterranean suggest that only some populations located in the North Atlantic may be able to rebuild, whereas the populations in southern North Atlantic and the Mediterranean, which are probably most at risk from sea warming, are facing serious difficulties in doing so. In the context of fisheries and global warming, this study's results strongly indicate that management bodies need to consider the health status of many of the populations of Molva species, particularly in southern European waters, before implementing their decisions.     

P2X7: a receptor with a split personality that raises new hopes for anti-cancer therapy

Purinergic Signalling -