Systematic revision of the genus Petromica Topsent (Demospongiae: Halichondrida), with a new species from the southwestern Atlantic

The status, scope and classification of the sublithistid demosponge genus Petromica Topsent are revised through morphological analysis of museum specimens of all seven species (including proposed synonyms and varieties), two of which were collected and observed in situ along the Brazilian coast (P. ciocalyptoides (Van Soest & Zea) and P. citrina sp. n.). The synonymy of Petromica and Monanthus Kirkpatrick with priority to the former is justified due to the consistent presence of monocrepid rhizoclone desmas and oxeas in an halichondroid arrangement, and to the lack of co-variance in other morphological characters among the species studied (presence and shape of papillae, surface texture, ectosomal skeleton and desma shape). The proposed synonymy of P. grimaldii Topsent and P. massalis Dendy is refuted due to differences in habit and spicule shape between the two species. Three forms described as varieties of Monanthus plumosus Kirkpatrick are raised to species level: P. plumosa (Kirkpatrick), P. tubulata (Kirkpatrick) and P. digitata (Burton). Phylogenetic analysis indicates that two possibly monophyletic clades may be recognized within Petromica, although with low bootstrap support (35–59%): (P. ciocalyptoides, P. citrina) and (P. grimaldii, P. massalis) (P. plumosa) (P. tubulata) (P. digitata). The classification of Petromica within the Halichondriidae (order Halichondrida) is supported by the confused reticulation of long oxeote spicules with ascending spicule tracts, present in all species of the genus.     

Evaluation of the effects of several zoanthamine-type alkaloids on the aggregation of human platelets

Ten zoanthamine-type alkaloids from two marine zoanthids belonging to the Zoanthus genus (Zoanthus nymphaeus and Zoanthus sp.) along with one semisynthetic derivative were evaluated for their antiplatelet activities on human platelet aggregation induced by several stimulating agents. 11-Hydroxyzoanthamine (11) and a synthetic derivative of norzoanthamine (16) showed strong inhibition against thrombin-, collagen- and arachidonic acid-induced aggregation, zoanthenol (15) displayed a selective inhibitory activity induced by collagen, while zoanthaminone (10) behaved as a potent aggregant agent. These evaluations allowed us to deduce several structure-activity relationships and suggest some mechanisms of action for this type of compounds.     

Chemical variability within the marine sponge Aplysina fulva

Dibromotyrosine-derived metabolites are of common occurrence within marine sponges belonging to the order Verongida. However, previous chemical analysis of crude extracts obtained from samples of the verongid sponge Aplysina fulva collected in Brazil did not provide any dibromotyrosine-derived compounds. In this investigation, five samples of A. fulva from five different locations along the Brazilian coastline and one sample from a temperate reef in the South Atlantic Bight (SAB) (Georgia, USA) were investigated for the presence of bromotyrosine-derived compounds. All six samples collected yielded dibromotyrosine-derived compounds, including a new derivative, named aplysinafulvin, which has been identified by analysis of spectroscopic data. These results confirm previous assumptions that dibromotyrosine-derived metabolites can be considered as chemotaxonomic markers of verongid sponges. The isolation of aplysinafulvin provides additional support for a biogenetic pathway involving an arene oxide intermediate in the biosynthesis of Verongida metabolites. It cannot yet be established if the chemical variability observed among the six samples of A. fulva collected in Brazil and the SAB is the result of different environmental factors, distinct chemical extraction and isolation protocols, or a consequence of hidden genetic diversity within the postulated morphological plasticity of this species.     

Seroepidemiological studies of HIV-1 infection in large Brazilian cities

The prevalence of HIV-1 antibodies in selected groups of individuals from Rio de Janeiro, S?o Paulo and Santos was determined retrospectively. These groups and respective prevalences were: hemophiliac patients from Rio de Janeiro (1983-1984) 98.0%; polytransfused hemodialysis patients from S?o Paulo (1985-1986) 3.0% and (1987) 7.7%; intravenous drug addicts from S?o Paulo and Rio de Janeiro (1986-1987) 15.9%; male prisoners from S?o Paulo (1988) 12.5%, and pregnant women from Santos (1988-1989) 3.6%. These data stress the magnitude of AIDS in Brazil.