Avaliação das atividades antimicrobiana, citotóxica, moluscicida e antioxidante de Bromelia antiacantha Bertol: (Bromeliaceae) / Evaluation of antimicrobial, cytotoxic, molluscicidal and antioxidant activities of Bromelia antiacantha Bertol: (Bromeliaceae)

A Bromelia antiacantha Bertol. (Bromeliaceae), conhecida como gravatá ou caraguatá, apresenta características medicinais, alimentícias e ornamentais. Neste trabalho foram avaliadas as atividades antifúngica, antibacteriana, citotóxica, moluscicida e antioxidante de extratos alcoólicos das folhas e frutos desta espécie. Na avaliação da atividade antimicrobiana pelo método de microdiluição os extratos alcoólicos não foram eficientes frente à cepa referência do fungo Candida albicans (ATCC 90028), cepas clínicas de C. albicans e C. glabrata, e frente às bactérias S. aureus (ATCC 6538), P. aeruginosa (ATCC 9027) e E. coli (ATCC 8739). A atividade citotóxica, avaliada pelo bioensaio de toxicidade sobre náuplios de Artemia salina Leach (TAS), foi positiva para ambos extratos, com valores de DL50 variando em torno de 620 µg mL-1 e 360 µg mL-1, para os extratos alcoólicos dos frutos e das folhas, respectivamente. A atividade moluscicida, avaliada frente a caramujos da espécie Biomphalaria glabrata (Molusca, Gastropoda), não mostrou toxicidade aguda para soluções de 400 µg mL-1. As propriedades antioxidantes dos extratos investigadas in vitro mediante o método de DPPH• foram consideradas modestas (~ 35 por cento de inibição na concentração de 1000 µg mL-1). Dentre as atividades biológicas que foram testadas a atividade citotóxica foi a mais pronunciada.

Bromelia antiacantha Bertol. (Bromeliaceae), popularly known as "gravatá" or "caraguatá", shows medicinal, nutritional and ornamental properties. In the present study, the alcoholic extracts of leaves and fruits of this species were evaluated for antifungal, antibacterial, cytotoxic, molluscicidal and antioxidant activities. The alcoholic extracts evaluated by microdilution method were not efficient against the standard strain of Candida albicans (ATCC 90028), clinical strains of C. albicans and C. glabrata, and S. aureus (ATCC 6538), P. aeruginosa (ATCC 9027) and E. coli (ATCC 8739). The cytotoxic activity evaluated by toxicity bioassay on nauplii of Artemia salina Leach (TAS) was positive for both extracts, with LD50 values ranging around 620 µg mL-1 and 360 µg mL-1 for alcoholic extracts from leaves and fruits, respectively. The molluscicidal activity evaluated against Biomphalaria glabrata (Mollusca, Gastropoda) did not present acute toxicity for 400 µg mL-1 solutions. The antioxidant properties of the extracts investigated in vitro using the DPPH• method were considered modest (~ 35 percent of inhibition at 1000 µg mL-1). Among the evaluated biological activities, cytotoxic activity was the most marked.

Microhabitat use by two rocky shore gastropods in an intertidal sandy substrate with rocky fragments

Praias arenosas em algumas partes do Canal São Sebastião, região sudeste do Brasil, têm sido constantemente submetidas a diferentes tipos de impacto como deposição de fragmentos rochosos na região entremarés. Como conseqüência, estes ambientes abrigam uma rica fauna com organismos tanto de costões rochosos quanto de praias arenosas. Em especial, duas espécies de gastrópode típicas de costões rochosos, Tegula viridula e Morula nodulosa, são muito abundantes nestes ambientes. Uma avaliação do uso de microhabitats por estas duas espécies revelou que elas ocupam os microhabitats disponíveis em diferentes proporções e que a presença de uma espécie esteve associada à ausência da outra. Morula nodulosa apresentou uma dispersão ao acaso ocupando áreas com sedimento e algas marrons ramificadas recobrindo os fragmentos de rocha. Tegula viridula apresentou uma dispersão agrupada associada à característica agrupada dos microambientes ocupados: presença de algas verdes incrustantes e ausência de sedimento e algas marrons ramificadas recobrindo os fragmentos de rocha. Os resultados indicam que T. viridula pode ser menos tolerante que M. nodulosa à inundação dos fragmentos rochosos por sedimento, um evento estocástico comum ao ambiente estudado.

Microhabitat use by two rocky shore gastropods in an intertidal sandy substrate with rocky fragments

Sandy beaches in some areas of the São Sebastião Channel in southeastern Brazil have unremittingly undergone a variety of impacts, including the deposition of rock fragments in the intertidal region. Consequently, these environments support a rich fauna comprising both sandy beach and rocky shore organisms. Two rocky shore gastropods, Tegula viridula and Morula nodulosa, are particularly abundant in such environments. An evaluation of the use of microhabitats by these two species revealed that they occupy the available microhabitats in different proportions and the presence of one species is associated with the absence of the other. Morula nodulosa is randomly dispersed, occupying mostly areas with rock fragments covered with sediment and branching brown algae. Tegula viridula shows a clumped dispersion associated with the patchiness of the microhabitats used: the presence of encrusting green algae and absence of sediment and branching brown algae covering the rocks. These findings suggest T. viridula has a lower tolerance than M. nodulosa to sand inundation of the rocky fragments, a stochastic event common to the environment in question.

Praias arenosas em algumas partes do Canal São Sebastião, região sudeste do Brasil, têm sido constantemente submetidas a diferentes tipos de impacto como deposição de fragmentos rochosos na região entremarés. Como conseqüência, estes ambientes abrigam uma rica fauna com organismos tanto de costões rochosos quanto de praias arenosas. Em especial, duas espécies de gastrópode típicas de costões rochosos, Tegula viridula e Morula nodulosa, são muito abundantes nestes ambientes. Uma avaliação do uso de microhabitats por estas duas espécies revelou que elas ocupam os microhabitats disponíveis em diferentes proporções e que a presença de uma espécie esteve associada à ausência da outra. Morula nodulosa apresentou uma dispersão ao acaso ocupando áreas com sedimento e algas marrons ramificadas recobrindo os fragmentos de rocha. Tegula viridula apresentou uma dispersão agrupada associada à característica agrupada dos microambientes ocupados: presença de algas verdes incrustantes e ausência de sedimento e algas marrons ramificadas recobrindo os fragmentos de rocha. Os resultados indicam que T. viridula pode ser menos tolerante que M. nodulosa à inundação dos fragmentos rochosos por sedimento, um evento estocástico comum ao ambiente estudado.

Population biology and distribution of the tanaid Kalliapseudes schubarti Mañé-Garzon, 1949, in an intertidal flat in Southeastern Brazil

The population biology and the spatial and temporal distribution of Kalliapseudes schubarti Mañé-Garzon, 1949, a common tanaidacean in mud flats and estuaries in southern and southeastern Brazil, was studied in the Araçá region, São Sebastiäo (SP), Brazil. This species showed a clustered dispersion in the area and the individuals were concentrated in the superficial sediment layer (5 cm). Higher densities of K. schubarti were recorded in areas characterized by moderately sorted fine sediment. Multiple regression analysis revealed a positive influence of the organic matter contents and a negative effect of the silt-clay contents on the abundance of K. schubarti. This species showed a marked temporal variation with very low abundance in winter and fall (March to August). Sexual dimorphism was evidenced with males being larger than females. Ovigerous females were also larger than pre-ovigerous ones. Sex ratio was skewed towards females. Seven cohorts were identified during the sampling period, the estimated longevity was 12 months, and no seasonal oscillation in growth was evidenced. The continuous reproduction, as evidenced by the presence of larval phases (manca II and neutron) and reproductive females throughout the year, and high fecundity among the tanaids associated with fast growth and limited longevity support the case for the opportunistic life strategy suggested for this species in the literature.

Daily activity of four tropical intertidal hermit crabs from Southeastern Brazil

This study describes the daily activity in a simulated high tide situation of four species of hermit crabs (Pagurus criniticornis, Clibanarius antillensis, C. sclopetarius, and C. vittatus) that coexist in an intertidal flat in southeastern Brazil. Observations were done in two-hour intervals during two subsequent days (48 h) in three replicate pools with thirty crabs each. Among species (between and within genera) there was an evident variation in activity patterns, of which three could be distinguished. The circadian activity patterns of C. antillensis and C. vittatus could be characterized as evening and nocturnal, with resting peaks during the morning and afternoon. The circadian activity pattern of C. sclopetarius was characterized by two marked peaks of inactivity, corresponding to dawn and evening, which could represent an intrinsic association with the semi-lunar tidal cycles of the study area. Pagurus criniticornis showed high activity not influenced by day/night conditions during the entire observed period. These activity pattern variations of the studied hermit crabs should be taken into account in designing further experiments. More precise and accurate interspecific behavioral comparisons among species could be achieved in nocturnal experiments, the high activity period of all species.

Functional behavior of tortoise hemoglobin Geochelone denticulata

The hemolysate from Geochelone denticulata contains two main hemoglobin components, as shown by ion exchange chromatography and polyacrylamide gel electrophoresis (PAGE). Electrophoresis under dissociating conditions showed three types of globin chains. The apparent molecular mass, as determined by gel filtration on Sephadex G-200, was compatible with tetrameric Hb, which was unable to polymerize. The G. denticulata Hb has a P50 value of 9.56 mm Hg at pH 7.4. The Hb oxygenation appears to be under the control of organic phosphates and hydrogen ion since it is strongly affected by those species. In the presence ATP or IHP the P50 values increased to 29.51 mm Hg and 54.95 mm Hg, respectively, at pH 7.4. The n50 was generally lower than 1.5 in stripped Hb, suggesting a dissociation of tetramers. In the presence of organic phosphates n50 values increased to approximately 2.5. The Bohr effect was evident in oxygen equilibrium experiments. The hematocrit (32 percent) and Hb concentration (5.7 mM as heme) of G. denticulata blood were substantially larger than those of G. carbonaria, but the methemoglobin levels were similar in both species, approximately 1 percent. Thus, the oxygen capacity of blood appears to be higher in G. denticulata than in G. carbonaria, particularly considering the functional properties of their Hbs, which would guarantee the survival of animals

Substrate use and selection in sympatric intertidal hermit crab species

Coexisting hermit crabs may competitively interact for shells and microhabitats, mainly when shell availability is habitat-related. Three species of Clibanarius (C. antillensis, C. sclopetarius, and C. vittatus) coexist in the intertidal region of Pernambuco Islet, Araçá Region, Säo Sebastiäo Channel, southeastern Brazil. This study evaluated crab preferences for four substrate types used by these species in nature (rocky shore, pebbles, sand, and mud) in allopatric (single species) and sympatric (three species) treatments in simulations of high tide and low tide. The substrate preference of the three hermit crabs did not vary between low and high tide situations. At low tide the crabs either moved into holes in the highly complex rocky substrate or buried themselves in mud. Substrate selection may explain the patterns of substrate use in nature only for C. vittatus. Clibanarius antillensis and C. sclopetarius showed closer similarities in the pattern of substrate selection in the sympatric treatment with the substrate use in nature than in allopatric treatment, indicating a positive influence (dependence) of the presence of one species on the presence of another. Use of sub-optimal substrates, mainly by C. antillensis, may be caused by other factors such as its low desiccation tolerances. If competition for space takes place among these species, it would be more intense between C. sclopetarius and C. vittatus given their higher overlap in substrate preference than between them and C. antillensis

Substrate use and selection in sympatric intertidal hermit crab species

Coexisting hermit crabs may competitively interact for shells and microhabitats, mainly when shell availability is habitat-related. Three species of Clibanarius (C. antillensis, C. sclopetarius, and C. vittatus) coexist in the intertidal region of Pernambuco Islet, Araçá Region, São Sebastião Channel, southeastern Brazil. This study evaluated crab preferences for four substrate types used by these species in nature (rocky shore, pebbles, sand, and mud) in allopatric (single species) and sympatric (three species) treatments in simulations of high tide and low tide. The substrate preference of the three hermit crabs did not vary between low and high tide situations. At low tide the crabs either moved into holes in the highly complex rocky substrate or buried themselves in mud. Substrate selection may explain the patterns of substrate use in nature only for C. vittatus. Clibanarius antillensis and C. sclopetarius showed closer similarities in the pattern of substrate selection in the sympatric treatment with the substrate use in nature than in allopatric treatment, indicating a positive influence (dependence) of the presence of one species on the presence of another. Use of sub-optimal substrates, mainly by C. antillensis, may be caused by other factors such as its low desiccation tolerances. If competition for space takes place among these species, it would be more intense between C. sclopetarius and C. vittatus given their higher overlap in substrate preference than between them and C. antillensis.

Espécies de ermitões coexistentes podem realizar interações competitivas por conchas e microambientes, principalmente quando a disponibilidade de conchas está relacionada aos microambientes. Três espécies de ermitões do gênero Clibanarius (C. antillensis, C. sclopetarius e C. vittatus) coexistem na região entremarés da Ilha de Pernambuco, região do Araçá, Canal de São Sebastião, Sudeste brasileiro. Este estudo avaliou a preferência dos ermitões por quatro tipos de substrato (costão, seixos, areia e lodo) utilizados por eles na natureza em tratamentos alopátricos (uma espécie) e simpátricos (três espécies) em situações simuladas de marés alta e baixa. A preferência por tipos de substrato não variou entre as simulações de marés alta e baixa. Na maré baixa, os ermitões deslocaram-se para buracos e fendas ou enterraram-se no lodo. A seleção de substratos pode explicar o padrão de uso de substratos na natureza apenas para C. vittatus. Clibanarius antillensis e C. sclopetarius apresentaram maiores similaridades na seleção de substratos no tratamento simpátrico e no uso na natureza que no tratamento alopátrico, indicando influência positiva (dependência) da presença de uma espécie em função da outra. O uso de substratos subótimos no campo, principalmente por C. antillensis, pode ter sido causado por outros fatores, como suas baixas tolerâncias à dessecação. Se houver competição por substratos entre as três espécies, ela será mais intensa entre C. sclopetarius e C. vittatus, dada a maior sobreposição na preferência por substratos entre essas espécies que entre elas e C. antillensis.

Functional behavior of tortoise hemoglobin Geochelone denticulata

The hemolysate from Geochelone denticulata contains two main hemoglobin components, as shown by ion exchange chromatography and polyacrylamide gel electrophoresis (PAGE). Electrophoresis under dissociating conditions showed three types of globin chains. The apparent molecular mass, as determined by gel filtration on Sephadex G-200, was compatible with tetrameric Hb, which was unable to polymerize. The G. denticulata Hb has a P50 value of 9.56 mm Hg at pH 7.4. The Hb oxygenation appears to be under the control of organic phosphates and hydrogen ion since it is strongly affected by those species. In the presence ATP or IHP the P50 values increased to 29.51 mm Hg and 54.95 mm Hg, respectively, at pH 7.4. The n50 was generally lower than 1.5 in stripped Hb, suggesting a dissociation of tetramers. In the presence of organic phosphates n50 values increased to approximately 2.5. The Bohr effect was evident in oxygen equilibrium experiments. The hematocrit (32%) and Hb concentration (5.7 mM as heme) of G. denticulata blood were substantially larger than those of G. carbonaria, but the methemoglobin levels were similar in both species, approximately 1%. Thus, the oxygen capacity of blood appears to be higher in G. denticulata than in G. carbonaria, particularly considering the functional properties of their Hbs, which would guarantee the survival of animals.

O hemolisado de Geochelone denticulata contém dois componentes principais, de acordo com a cromatografia de troca iônica e PAGE. Eletroforese sob condições dissociantes mostrou 3 tipos de cadeias de globina. A massa molecular aparente, determinada pela filtração em gel sobre Sephadex G-200, foi compatível com Hb tetramérica que foi incapaz de polimerizar. A Hb de G. denticulata tem valor de P50 de 9,56 mm Hg em pH 7,4. A oxigenação da Hb parece estar sob controle de fosfatos orgânicos e íons hidrogênio, uma vez que ela é fortemente afetada por essas espécies. Na presença de ATP ou IHP, os valores de P50 aumentaram para 29,51 mm Hg e 54,95 mm Hg, respectivamente, a pH 7,4. O n50 foi geralmente menor que 1,5 na Hb stripped, sugerindo dissociação de tetrâmeros. Na presença de fosfatos orgânicos, os valores de n50 aumentaram para aproximadamente 2,5. O efeito Bohr foi evidente nos experimentos de equilíbrio com oxigênio. O hematócrito de 32% e a concentração de Hb de 5,7 mM em heme no sangue de G. denticulata foram substancialmente maiores do que da G. carbonaria, mas os níveis de metahemoglobina foram similares em ambas as espécies, aproximadamente 1%. Portanto, a capacidade de oxigenação do sangue parece ser maior na G. denticulata, particularmente considerando as propriedades funcionais da Hb, que garantiria a sobrevivência dos animais.