Radiation of the genus Dysdera (Araneae, Haplogynae, Dysderidae) in the Canary Islands: The western islands

The spider genus Dysdera has undergone an extraordinary species radiation in the Canary Islands. As a first step towards the recovery of the endemic species phylogeny and the study of the evolutionary processes underlying its diversification, an exhaustive taxonomical work is required. The present paper deals with the endemic species that inhabit the western Canaries: La Gomera, La Palma and El Hierro. Four new species are described: Dysdera enghoffi sp. n., D. hirguan sp. n., D. orahan sp. n. and D. ramblae sp. n. Three new synonymies are reported: D. palmensis Schmidt, 1982 = D. crocota Koch, 1839, D. multipilosa Wunderlich, 1991 = D. levipes Wunderlich, 1987 and D. silvatica Schmidt, 1981 = D. rugichelis Simon, 1907. Four species are redescribed: D. calderensis Wunderlich, 1991 D. clavisetae Wunderlich, 1991 D. levipes Wunderlich, 1987 and D. rugichelis Simon, 1907 for which a neotype is designated. The presence on the western islands of the formerly described species D. insulana Simon, 1883, D. macra Simon, 1883 and D. nesiotes Simon, 1907 are considered to be doubtful. The citation of D. cribellata Simon, 1883 in La Palma (Simon, 1907) was based on a mis-identification. The species D. gomerensis Strand, 1911 is designated as a nomen dubium. Morphological affinities as well as ecology and distribution of the species are discussed.     

Effects of the Neotyphodium endophyte fungus on dormancy and germination rate of Lolium multiflorum seeds

Abstract Neotyphodium frequently occurs as an endophyte in grasses. Evidence shows enhanced fitness of endophyte infected grasses relative to non‐infected ones. Some studies of seed germination show endophyte enhancement of plant fitness in various environments, but inconsistent results indicate that further studies are needed. So far, experiments have failed to separate the confounded effects of population origin and seed management. For this reason, we evaluated the effects of endophyte infection on seed dormancy and germination in Lolium multiflorum using an experimental design controlling these factors. Depending on the year of seed production, endophyte infection modified seed response to light quality, affecting predominantly seed dormancy levels. Nevertheless, the endophyte did not affect base temperature or thermal time of germination. We concluded that endophytes were not a strong influence on germination behaviour. We speculate from our results that the presence of the endophyte changes germination by an indirect effect, in extending growth of the maternal plant during seed development and ripening. The direct effect of hyphae in the seed on seed behaviour was disregarded, because the difference between infected and non‐infected seed varied within the year of seed production. Future experiments should focus on effects of the endophyte on the canopy of parent plants during seed production and ripening, and, hence, on subsequent dormancy and germination of the seeds.     

Immunological response in rabbits infested with Rhipicephalus sanguineus

Abstract. In order to clarify the importance of humoral antibody in host resistance to ticks, in the present work we studied the immunological response of rabbits infested with larvae, nymphs or adults of Rhipicephalus sanguineus , using extracts of eggs (EE), larvae (LE), nymphs (NE), male salivary glands (MSGE), male midguts (MME), female salivary glands (FSGE) and female midguts (FME). When serum from rabbits infested with larvae or nymphs was tested using enzyme-linked immunosorbent assay, no reactions were observed with any of the extracts including the homologous LE or NE. In sera from rabbits infested with adult ticks, the reactions were observed in both homologous (MSGE, MME, FSGE and FME) and heterologous (EE, LE and NE) system. However, differences were seen regarding the type of antigen used. When the experiment was carried out using extracts from adults higher responses were found. With FSGE and FME antigens, antibody levels were systematically higher than those observed when MSGE and MME were used.     

Comparison of TRPs From Murine and Human Malignant Melanocytes

Most of our knowledge of the mammalian tyrosinase related protein (TRP) activities is derived from studies using murine melanoma models, such as B16 or Cloudman S-91 melanocytes. Owing to the high degree of homology between the murine and human enzymes, it has been assumed that their kinetic behavior could be similar. However, the protein sequences at the metal binding sites of the murine and human enzymes show some differences of possible functional relevance. These differences are more significant in the metal-A site than in the metal-B site. By using three human melanoma cell lines (HBL, SCL, and BEU), we have studied the catalytic abilities of the human melanogenic enzymes in comparison to those obtained for the counterpart murine enzymes isolated from B16 melanoma. We have found that TRP2 extracted from all cell lines show dopachrome tautomerase activity, although the activity levels in human malignant melanocytes are much lower than in mouse cells. Reconstitution experiments of the human enzyme indicate that TRP2 has Zn at its metal binding-sites. Although mouse tyrosinase does not show DHICA oxidase activity, and this step of the melanogenesis pathway is specifically catalyzed by mouse TRP1, the human enzyme seems to recognize carboxylated indoles. Thus, human tyrosinase could display some residual DHICA oxidase activity, and the function of human TRP1 could differ from that of the murine protein. Attempts to clarify the nature of the metal cofactor in TRP1 were unsuccessful. The enzyme contains mostly Fe and Cu, but the reconstitution of the enzymatic activity from the apoprotein with these ions was not possible.     

Somatic and cognitive domains of depression in an underserved region of Ecuador: some cultural considerations

Not enough research efforts on depression have been carried out up to now in Latin America. The knowledge that has resulted from research activities in the United States or Europe offers limited generalizability to other regions of the world, including Latin America. In the Andean highlands of Ecuador, we found very high rates of moderate and severe depressive symptoms, a finding that must be interpreted within its cultural context. Somatic manifestations of depression predominated over cognitive manifestations, and higher education level was protective against depression. These findings call for an appreciation of culturally-specific manifestations of depression and the social factors that influence them. These factors must be further studied in order to give them the deserved priority, allocate resources appropriately, and formulate innovative psychosocial interventions.