Subcellular Distribution of Two Spin Trapping Agents in Rat Heart: Possible Explanation for Their Different Protective Effects Against Doxorubicin-Induced Cardiotoxicity

Previous investigations, performed on isolated rat atria, showed that the lipophylic spin-trapping agent N-tert-butyl-alpha-phenylnitrone (PBN) is able to prevent the acute cardiotoxic effects produced by doxorubicin (DXR), whereas the hydrophylic compound 5,5-dimethyl-pyrroline-N-oxide (DMPO) is inactive. The present study was designed to ascertain whether differences in the pharmacological effects of the two spin traps are related to their different subcellular distribution. Langendorff rat hearts were perfused for 60 minutes with [^I4C]-DXR and either PBN or DMPO. The subcellular mapping of the three compounds was performed by measuring DXR by liquid scintillation counting, PBN by GC/MS, and DMPO by HPLC in the following isolated fractions: nuclei, mitochondria, sarcoplasmic reticulum, sarcolemma, cytosol. DMPO was shown to accumulate in the cytosolic compartment; both PBM and DXR are taken up by nuclei and mitochondria, while only trace amounts of DXR were detected in the sarcoplasmic reticulum. These results suggest that mitochondrial (and not sarcoplasmic) enzymes are mainly involved in DXR-induced free radical production, which is thought to cause the acute cardiotoxic effects of DXR. An involvement of DXR-induced free radical generation in the nuclear compartment seems unlikely in the short-term “in vitro” effects observed with the experimental model adopted for these studies, although it may play a role in the delayed pathology.     

Skipper impoverishment on large West Mediterranean islands (Lepidoptera Hesperioidea): deterministic,historical and stochastic factors

Biogeographical analyses are applied to skipper (Hesperioidea) presence/absence data from the Western Mediterranean mainland and the three largest islands (Sardinia, Corsica and Sicily) in order to identify potential conservation issues. The analyses performed on species, both collectively and individually, indicate that regional species richness and occurrence in the Mediterranean zone are largely predicted by latitude and area but that islands have impoverished faunas. Several species, predicted to be present on these islands from logistic regression of their continental distributions, are actually absent. The number of species predicted to be present from logistic regression analyses for each island, closely matched the number of species predicted to occur in regional-focused multiple regression analysis. This suggests that missing species have been identified. When compared with species that occur in Sicily and Corsica, the missing species are shown to differ for ecological traits, mainly those linked to altitudinal tolerance. No ecological distinctions were disclosed for Sardinian skippers suggesting a mainly stochastic colonisation. These results, and those from an analogous study carried out on Papilionoidea, point to Hesperioidea having (i) overall more impoverished faunas on islands and (ii) being subject to stochastic or historical colonisation events more than Papilionoidea. Species not predicted to occur on islands based on their mainland distributions and ecological traits, are foci for conservation attention. However, as many species becoming extinct on the islands may be irreplaceable, all species, in particular the Sardinian ones, deserve to be conserved.     

Effects of hydrogen peroxide on the content of major volatile halogenated compounds in the red alga <Emphasis Type="Italic">Asparagopsis taxiformis</Emphasis> (Bonnemaisoniaceae)

The genus Asparagopsis is a prolific source of halogenated metabolites. Due to its commercial applications, it has been intensively cultivated in southern Portugal. In the present study, we assess if the internal levels of the major halogenated metabolites (bromoform and dibromoacetic acid) in Asparagopsis taxiformis can be increased with hydrogen peroxide (H₂O₂) addition. Previous studies with red algae showed that the production/release of bromoform can be enhanced by exogenously supplying H₂O₂. However, no study has assessed if H₂O₂ supply enhances the content of secondary metabolites within the biomass. This detail is important as the objective of the proposed research is to enhance the content of these valuable metabolites in the produced biomass. Both the activity of the haloperoxidase enzyme and the metabolite content were assessed on short-term and long-term incubation periods to H₂O₂. To determine the susceptibility of A. taxiformis photosynthetic performance to the imposed oxidative stress, the in vivo fluorescence of photosystem II was monitored. A. taxiformis was shown to be physiologically vulnerable to H₂O₂, given the observed decrease of the maximum quantum yield of photosynthesis (F _v/F _m). Contrary to what was expected, the presence of H₂O₂ inhibited the activity of the iodoperoxidase enzyme. Nevertheless, the extracted halogenated metabolites were higher over the first hours of exposure to H₂O₂, decreasing after 48 h. These results are probably related to the prosthetic group of the halogenated enzyme in A. taxiformis and the long-term oxidative stress damage of H₂O₂ exposure. Considering the objective of the proposed research, addition of H₂O₂ to the cultures, prior (3 h) to biomass harvesting, increases the metabolite content.     

Virtual brain endocast of Antifer (Mammalia: Cervidae), an extinct large cervid from South America

A diverse fossil record of Cervidae (Mammalia) has been documented in the South American Pleistocene, when these animals arrived during the Great American Biotic Interchange. Using computed tomography-scanning techniques, it is possible to access the endocranial morphology of extinct species. Here, we studied the brain endocast of the extinct late Pleistocene cervid Antifer ensenadensis from southern Brazil, one of the largest forms that lived on this continent, using comparative morphology, geometric morphometrics, and encephalization quotients. The analyzed endocasts demonstrate that A. ensenadensis had a gyrencephalic brain, showing a prominent longitudinal sinus (=sagittal superior sinus), which is also observed in the large South American cervid Blastocerus dichotomus. The encephalization quotient is within the variation of extant cervids, suggesting maintenance of the pattern of encephalization from at least the late Pleistocene. Geometric morphometric analysis suggested a clear and linear allometric trend between brain endocast size and shape, and highlights A. ensenadensis as an extreme form within the analyzed cervids regarding brain morphology.     

Incipient morphological castes in <Emphasis Type="Italic">Polistes gallicus</Emphasis> (Vespidae,Hymenoptera)

The occurrence of a pre-imaginal caste determination represents a sort of “point of no return” to eusociality. In some social insect taxa, including Polistes species, the occurrence of distinct queen and worker castes is still debated. Before this report, no clear morphological differences between reproductive and non-reproductive individuals were known. Here we show that several pre-imaginal morphological differences of the Van der Vecht organ occur between foundresses (queens) and workers. Geometric morphometrics revealed that queens are characterized by shape deformations of this organ, which is responsible for a typical allometric growth of the secretory area. This organ is predicted to be larger in foundresses compared to workers because its secretion is involved in defense against ants, in nestmate recognition and in preventing workers from challenging for direct reproduction. The results presented here indicate the existence of an incipient morphological caste determination Polistes gallicus and suggest that this species may have passed the “point of no return” for eusociality.     

Phylogenetic island disequilibrium: evidence for ongoing long‐term population dynamics in two Mediterranean butterflies

Aim Our aims were to verify the existence of phylogenetic disequilibrium between butterfly lineages at the subcontinental scale for islands and the nearest mainland and to test the capacity of islands for hosting ancestral populations of butterflies and the significance of such relict populations. Location The western Mediterranean continental area of Europe and North Africa together with several large and small islands (Balearics, Tuscan Archipelago, Aeolian Archipelago, Capri, Sardinia, Sicily, Corsica). Methods Using geometric morphometrics, the shape of male genitalia was analysed in two common butterflies (Pyronia cecilia and Pyronia tithonus), whose spatial heterogeneity in the Mediterranean region has recently been described. Observed patterns in genital shapes were compared with shapes predicted for islands and fossil islands to assess the contribution of historical and current events in accounting for the transition from a refugial model to an equilibrium model. Measurements were taken for 473 specimens in 90 insular and mainland sites. Results The shape of the genitalia of populations of most islands differed substantially from that predicted by the equilibrium hypothesis while closely fitting the refugial hypothesis. The comparison between different models strongly suggests that islands maintain ancestral lineages similar to those living in Spain (P. cecilia) and France (P. tithonus). A high correlation between observed and predicted patterns on islands and fossil islands occurs during the first steps of modelled introgressive hybridization while the following steps exposed a successively lower fit, suggesting that the process from a refugial to an equilibrium situation is highly skewed towards an earlier non‐equilibrium. Main conclusions The observed non‐equilibrium pattern supports the refugial hypothesis, suggesting that an ancestral lineage was originally distributed from Spain to Italy, and also occupied offshore islands. This lineage, replaced in Italy, has persisted on the islands owing to their isolation. A comparison of the distribution patterns for genetic and morphometric markers in several species indicates that the situation highlighted for Pyronia may represent a common biogeographic feature for many Mediterranean butterflies.     

The Scientific Impact of Developing Nations

This paper analyzes science productivity for nine developing countries. Results show that these nations are reducing their science gap, with R&D investments and scientific impact growing at more than double the rate of the developed world. But this “catching up” hides a very uneven picture among these nations, especially on what they are able to generate in terms of impact and output relative to their levels of investment and available resources. Moreover, unlike what one might expect, it is clear that the size of the nations and the relative scale of their R&D investments are not the key drivers of efficiency.     

Recent advances in shoulder research

Shoulder pathology is a growing concern for the aging population, athletes, and laborers. Shoulder osteoarthritis and rotator cuff disease represent the two most common disorders of the shoulder leading to pain, disability, and degeneration. While research in cartilage regeneration has not yet been translated clinically, the field of shoulder arthroplasty has advanced to the point that joint replacement is an excellent and viable option for a number of pathologic conditions in the shoulder. Rotator cuff disease has been a significant focus of research activity in recent years, as clinicians face the challenge of poor tendon healing and irreversible changes associated with rotator cuff arthropathy. Future treatment modalities involving biologics and tissue engineering hold further promise to improve outcomes for patients suffering from shoulder pathologies.