Moluscos encontrados no Sambaqui de Camboinhas, Itaipu, Niterói, estado do Rio de Janeiro, Brasil

Archaelogical aspects of Camboinhas' kitchen midden, Itaipu, Niterói, Rio de Janeiro State are presented, as well as samples of mollusca species found in the kitcheen midden.

Potential schistosome-vector snails and associated trematodes in ricefields of Corrients province, Argentina: preliminary results

Considering the possibility of introduction of schistosomiasis mansoni into Argentina as a consequence of dam construction on the Rio De La Plata basin, preliminary studies have been carried out on agrosystems such as ricefields in Corrientes province with the following purposes: 1) to survey and estimate the relative abundance of planorbids and identify potential vector species; 2) to identify environmental factors capable of influencing Biomphalaria population dynamics; and 3) to find out snail-parasite associations and estimate snail infection rates in order to detect possible competitive interactions between larval stages of native trematodes that could be used in biological control of Schistosoma mansoni. Three potential schistosome vectors were detected in ricefields, namely Biomphalaria straminea, B. tenagophila and B. peregrina, although B. orbignyi, a species refractory to infection with S. mansoni, proved the most frequent and abundant. Positive correlations (P<0.05) were found between Biomphalaria abundance and some environmental parameters: conductivity, hardness, calcium, nitrites plus nitrates, ammonium and bicarbonates. Water temperature correlation was negative (P<0.05). No correlation (P>0.05) was found in total iron, phosphates (SRP), pH and soil granulometry. Echinocercariae developed from rediae and belonging to Petasiger sp., Paryphostomum sp., and other undetermined species were found.

Parasitic castration in Fissurella crassa (Archaeogastropoda) due to an adult Digenea, Proctoeces lintoni (Fellodistomidae)

Specimens of Fissurella crassa (Archaeogastropoda) from Ilo, southern Perú, are infected with the adult stage of the digenetic trematode Proctoeces lintoni (Fellodistomidae). The histopatological analysis of the male and female gonads show a strong effect of the parasite on the structure and function of these organs. P. lintoni live unencysted in the gonads, and the main mechanical damage is originated by the action of a well developed acetabulum. Chemical actions of parasitic secretions may also be involved. The infected gonads show altered structure and the gametogenic processes is aborted. There is no evidence of hemocytic response, but leucocite infiltration is evident at least in male infected gonads. An increased content of polysaccarides is evident in infected gonads.

Spatial and seasonal trends of a natural population of Biomphalaria occidentalis in northeastern Argentina

This study aims to analyze the age of a population of Biomphalaria occidentalis on a pound of Riachuelo river basin, wich is one of the three most important Middle Paraná river affluents in Corrientes province. Samples were drawn from three stations, were spatial and temporal numerical variations of the snail, as well as its relation with different environmental parameters, mainly temperature, rainfall, pH and conductivity, were analyzed. Snail abundance is given in number of individuals/hour. The differences between the three sampling stations, estimated by nonparametric tests, was nonsignificant. A relative scale to the greatest shell diameter was employed to build the age pyramids. Temporal fluctuations of snail abundance correlated negatively with the highest monthly accumulated temperatures (P < 0.05). Although different floristic compositions were observed at the three stations, no significant numerical variations were detected in B. occidentalis spatial distribution. Reproductive activity took place between March-April and November with overlapping cohort system. During summer (December-Febuary) mortality increased along with temperature and reproductive activity was not evident.

Biomphalaria occidentalis paraense, 1981 in the state of Minas Gerais, Brazil

A population of Biomphalaria occidentalis was found for the first time in the State of Minas Gerais. It was probavly introduced into the Várzea das Flores dam, in the municipality of Contagem, the area o0f study, during fish stocking in 1985. There is possibility of "competitive exclusion"between that species and B. glabrata, previously the only Biomphalaria found in the region. The present geographical distribution of B. occidentalis in Brazil is listed.

Neotropical planorbid snails with apertural lamellae: I. Biomphalaria helophila (Orbigny, 1835)

A definition of Biomphalaria helophila (Orbigny, 1835) is presented, based on examination of the shell and reproductive system of topotypic specimens and extended to a number of samples from other localities. The following nominal species and subspecies, collected from type localities, proved junior synonyms of B. helophila: Planorbis albicans Pfeiffer, 1839; Planorbis dentatus Gould, 1844; Planorbis dentiferus CB Adams, 1845; Planorbis dentiferus edentatus CB Adams, 1851; Planorbis dentiens Morelet, 1849; Planorbula dentiens edentula Fischer & Crosse, 1880; Planorbis stagnicola Morelet, 1851; and Tropicorbis shimeki FC Baker, 1945. B. helophila was also identified in samples from Costa Rica, Guatemala, Haiti, Dominican Republic, Puerto Rico and Barbados.

Genetic variability in Brazilian populations of Biomphalaria straminea complex detected by simple sequence repeat anchored polymerase chain reaction amplification

Biomphalaria glabrata, B. tenagophila and B. straminea are intermediate hosts of Schistosoma mansoni, in Brazil. The latter is of epidemiological importance in the northwest of Brazil and, due to morphological similarities, has been grouped with B. intermedia and B. kuhniana in a complex named B. straminea. In the current work, we have standardized the simple sequence repeat anchored polymerase chain reaction (SSR-PCR) technique, using the primers (CA)8RY and K7, to study the genetic variability of these species. The similarity level was calculated using the Dice coefficient and genetic distance using the Nei and Li coefficient. The trees were obtained by the UPGMA and neighbor-joining methods. We have observed that the most related individuals belong to the same species and locality and that individuals from different localities, but of the same species, present clear heterogeneity. The trees generated using both methods showed similar topologies. The SSR-PCR technique was shown to be very efficient in intrapopulational and intraspecific studies of the B. straminea complex snails.

Indicadores de qualidade de solos de área de mineração e metalurgia de chumbo: II - Mesofauna e plantas

A influência do manejo ou a adição de contaminante ao solo, normalmente, induz uma resposta mais rápida sobre a mesofauna do solo do que em outros atributos pedológicos, o que torna esses organismos bons indicadores de qualidade ambiental. Os objetivos deste trabalho foram identificar e quantificar os grupos de organismos da mesofauna dos solos e determinar os teores de Pb e Zn de plantas da área de mineração e metalurgia de Pb, no município de Adrianópolis (PR), de modo que fossem gerados indicadores biológicos da qualidade desses solos. Os solos selecionados apresentaram as seguintes características em relação às formas de contaminação: solo 1 - referência (mata nativa); solo 2 - resíduos incorporados ao perfil; solos 3 e 6 - próximos às chaminés da fábrica, com potencial de aporte de material particulado; e solo 5 - grande volume de rejeitos sobre o solo. Foram utilizados funis de Berlese, coletando-se amostras na profundidade de 0 a 5 cm (20 funis x 5 solos x 1 profundidade x 4 épocas = 400 amostras). Após separação da mesofauna, procedeu-se à triagem e identificação dos organismos com o auxílio de lupa. Amostras de formiga foram digeridas com HNO3 concentrado em sistema fechado de micro-ondas, e os teores de Pb e Zn foram determinados por espectroscopia de emissão atômica com plasma indutivamente acoplado (ICP-AES). Plantas da família Poaceae foram coletadas em todos os solos e, após digestão das amostras da parte aérea e da raiz pelo método nítrico-perclórico, determinaram-se os teores de Pb e Zn por ICP-AES. O número total de organismos dos 21 grupos identificados e o Índice de Qualidade Ambiental da Mesofauna não foram bons indicadores do nível de contaminação dos solos por metais pesados. A ocorrência e distribuição de espécies isoladas mostraram-se mais eficientes nesse propósito. A melhor qualidade ambiental do solo 1 (teores naturais de Pb - solo de referência) foi atestada pela maior riqueza de grupos de organismos e ocorrência de representantes dos grupos Pseudoscorpiones, Mollusca e Isopoda apenas nesse solo. Os grupos Aracnídeos e Psocoptera também foram considerados bons indicadores ambientais, com incremento de suas populações nos solos com maiores teores de metais pesados (solos 2, 3 e 5), possivelmente devido à menor ocorrência de organismos competidores/predadores desses grupos. Os teores de metais pesados nos indivíduos do grupo Formicidae tiveram relação direta com os teores de Pb extraídos com HNO3 0,5 mol L-1 no solo. Quanto ao acúmulo de metais pesados nas plantas coletadas na área, com exceção do solo 1, todas as espécies encontravam-se sob efeito fitotóxico para Pb e Zn, o que sugere a proibição de pastejo na área.