Implementing new northernmost records to modelling the distribution of Hypsiboas caingua (Anura: Hylidae) in South America / Uso de novos registros ao norte para a modelagem de distribuição de Hypsiboas caingua (Anura: Hylidae) na América do Sul

New northwestern records of the striped treefrog Hypsiboas caingua (Carrizo, 1991 “1990”) are presented for Brazil, extending its known geographic distribution approximately 115 km northward (linear distance) of the previous northernmost record of the species. In all new localities, individuals of H. caingua were only found in calling activity under temperatures below 18°C. The species appears to be associated with Atlantic Forest, although it had already been recorded in Cerrado. Although the scientific literature data suggests that H. caingua presents discontinuous geographical distribution, three methods of distribution modelling based on climatic data show that the species' distribution is continuous. The gap in the distribution may be related to the lack of field surveys in the regions that connect these populations, especially in colder periods. Nevertheless, factors other than climate might also be responsible for the current distribution of H. caingua, since the species was absent in well-surveyed sites situated between the areas of modeled distribution. Therefore, further studies on natural history, populations' genetic structure, and geographic distribution models implementing factors other than climate will be important to elucidate some ecological and evolutionary aspects of the distribution of H. caingua in South America.

Novos registros da perereca Hypsiboas caingua (Carrizo, 1991 “1990”) são apresentados para o noroeste do Brasil, ampliando sua distribuição geográfica em aproximadamente 115 km ao norte (distância linear) em relação ao registro anterior setentrional da espécie. Em todas as novas localidades, indivíduos de H. caingua foram apenas encontrados vocalizando sob temperaturas abaixo de 18 °C. A espécie aparenta estar associada com a Mata Atlântica, embora já tenha sido registrada no Cerrado. Apesar de dados da literatura científica sugerirem que H. caingua apresente distribuição geográfica descontínua, os três métodos de modelagem de distribuição, baseados em dados climáticos demonstram que a distribuição da espécie é contínua. A lacuna na distribuição pode estar relacionada à ausência de levantamentos de campo nas regiões que conectam essas populações, principalmente em períodos frios. Contudo, outros fatores além do climático também podem ser responsáveis pela atual distribuição de H. caingua, visto a ausência da espécie em locais bem amostrados situados entre as áreas de distribuição modeladas. Portanto, mais estudos sobre a história natural, genética de populações e modelos de distribuição geográfica que abordem outros fatores além do clima, serão importantes para elucidar alguns aspectos ecológicos e evolucionários da distribuição de H. caingua na América do Sul.

Implementing new northernmost records to modelling the distribution of Hypsiboas caingua (Anura: Hylidae) in South America.

New northwestern records of the striped treefrog Hypsiboas caingua (Carrizo, 1991 "1990") are presented for Brazil, extending its known geographic distribution approximately 115 km northward (linear distance) of the previous northernmost record of the species. In all new localities, individuals of H. caingua were only found in calling activity under temperatures below 18°C. The species appears to be associated with Atlantic Forest, although it had already been recorded in Cerrado. Although the scientific literature data suggests that H. caingua presents discontinuous geographical distribution, three methods of distribution modelling based on climatic data show that the species' distribution is continuous. The gap in the distribution may be related to the lack of field surveys in the regions that connect these populations, especially in colder periods. Nevertheless, factors other than climate might also be responsible for the current distribution of H. caingua, since the species was absent in well-surveyed sites situated between the areas of modeled distribution. Therefore, further studies on natural history, populations' genetic structure, and geographic distribution models implementing factors other than climate will be important to elucidate some ecological and evolutionary aspects of the distribution of H. caingua in South America.

Structure of aquatic vegetation of a large lake, western border of the Brazilian Pantanal.

Studies on Neotropical aquatic macrophytes have increased in recent decades, however species richness in wetlands of South America is far from being fully known. In addition, studies having an ecological approach are scarce in the Pantanal. Rapid assessments are essential for gaining knowledge of the biodiversity in the region. This study was performed in five sites of the Baía do Castelo, the western border of the Brazilian Pantanal, which included wild-rice patches, floating mats and floating meadows. At each site, plots of 0.5 × 0.5 m were set (n = 137), species of aquatic macrophytes were identified, their coverage was measured and the plot depth was estimated. We recorded 57 species in 26 families, of which Poaceae was the richest. The most frequent and abundant species was Commelina schomburgkiana; the second most frequent was Oryza latifolia,followed by Leersia hexandra, Enydra radicans and Pityrogramma calomelanos. The latter species was second in cover, followed by Pontederia rotundifolia, Eichhornia azurea, E. crassipes and Enydra radicans. These five species and C. schomburgkiana (the most abundant) together represent more than half of the coverage on the lake. Pontederia rotundifolia, Ludwigia helminthorrhiza, Pistia stratiotes, E. azurea, E. crassipes, Enydra radicans and Panicum elephantipes were strongly associated with deeper areas, while Oryza latifolia, Leersia hexandra and Salvinia auriculata were prevalent in shallow areas. Pityrogramma calomelanos, Ludwigia nervosa, Ipomoea alba, Cayaponia podantha, Polygonum acuminatum, Rhynchanthera novemnervia and Ludwigia leptocarpa were highly correlated with floating meadows. The structure of the habitat, natural dynamics and zonation of aquatic vegetation in the Baía do Castelo seems to be influenced by a variation in water levels, which promotes spatial segregation, most likely due to competition and/habitat preference.

Structure of aquatic vegetation of a large lake, western border of the Brazilian Pantanal / Estrutura da vegetação aquática em uma grande lagoa, borda oeste do Pantanal brasileiro

Studies on Neotropical aquatic macrophytes have increased in recent decades, however species richness in wetlands of South America is far from being fully known. In addition, studies having an ecological approach are scarce in the Pantanal. Rapid assessments are essential for gaining knowledge of the biodiversity in the region. This study was performed in five sites of the Baía do Castelo, the western border of the Brazilian Pantanal, which included wild-rice patches, floating mats and floating meadows. At each site, plots of 0.5 × 0.5 m were set (n = 137), species of aquatic macrophytes were identified, their coverage was measured and the plot depth was estimated. We recorded 57 species in 26 families, of which Poaceae was the richest. The most frequent and abundant species was Commelina schomburgkiana; the second most frequent was Oryza latifolia,followed by Leersia hexandra, Enydra radicans and Pityrogramma calomelanos. The latter species was second in cover, followed by Pontederia rotundifolia, Eichhornia azurea, E. crassipes and Enydra radicans. These five species and C. schomburgkiana (the most abundant) together represent more than half of the coverage on the lake. Pontederia rotundifolia, Ludwigia helminthorrhiza, Pistia stratiotes, E. azurea, E. crassipes, Enydra radicans and Panicum elephantipes were strongly associated with deeper areas, while Oryza latifolia, Leersia hexandra and Salvinia auriculata were prevalent in shallow areas. Pityrogramma calomelanos, Ludwigia nervosa, Ipomoea alba, Cayaponia podantha, Polygonum acuminatum, Rhynchanthera novemnervia and Ludwigia leptocarpa were highly correlated with floating meadows. The structure of the habitat, natural dynamics and zonation of aquatic vegetation in the Baía do Castelo seems to be influenced by a variation in water levels, which promotes spatial segregation, most likely due to competition and/habitat preference.

Estudos sobre macrófitas aquáticas Neotropicais aumentaram nas últimas décadas; todavia, a riqueza de espécies em áreas úmidas da América do Sul está longe de ser plenamente conhecida. Além disso, trabalhos com abordagem ecológica são escassos no Pantanal. Por essa razão, levantamentos rápidos são essenciais para o conhecimento sobre a biodiversidade. Este estudo foi realizado em cinco pontos na Baía do Castelo, borda oeste do Pantanal brasileiro, os quais incluíram arrozal, camalotal e baceiros. Em cada ponto, foram estabelecidas parcelas 0.5 × 0.5 m (n = 137), onde foram identificadas as espécies de macrófitas aquáticas, estimada a cobertura e tomada a profundidade. Registramos 57 espécies distribuídas em 26 famílias, das quais a mais rica foi a Poaceae. A espécie mais frequente e abundante foi Commelina schomburgkiana; a segunda mais frequente foi Oryza latifolia, seguida por Leersia hexandra, Enydra radicans e Pityrogramma calomelanos. Essa última espécie foi a segunda com maior cobertura, seguida por Pontederia rotundifolia, Eichhornia azurea, E. crassipes e Enydra radicans. Essas cinco espécies juntamente com C. schomburgkiana (a mais abundante) representam mais da metade da cobertura na Baía do Castelo. Pontederia rotundifolia, Ludwigia helminthorrhiza, Pistia stratiotes, E. azurea, E. crassipes, E. radicans e Panicum elephantipes foram fortemente relacionadas às áreas mais profundas, enquanto Oryza latifolia, Leersia hexandra e Salvinia auriculata foram relacionadas a areas mais rasas. Pityrogramma calomelanos, Ludwigia nervosa, Ipomoea alba, Cayaponia podantha, Polygonum acuminatum, Rhynchanthera novemnervia e Ludwigia leptocarpa foram altamente correlacionadas com baceiros. A estrutura do habitat, a dinâmica natural e a zonação da vegetação aquática aparentam ser influenciadas pela variação nos níveis d'água na Baía do Castelo, os quais promovem a segregação espacial, provavelmente pela competição e/ou preferência por habitat.

Differential synthesis and binding of hyaluronan by human breast cancer cell lines.

In the present study we investigated a panel of human breast cancer cell lines which were sensitive or resistant to the cytotoxic drug doxorubicin, for their abilities to synthesize and bind hyaluronan. We found that MDA-231 and HS-578T cells which express very low amounts of estrogen and progesterone receptors, both synthesized hyaluronan and expressed hyaluronan binding sites on the cell surface as did their doxorubicin-adapted counterparts MDA-231 Dox and HS-578T Dox. The binding was highly specific with a K-d of 0.48x10(-9) M. Most of the hyaluronan binding activity was blocked by mAbs against Hermes-l antigen indicating that the adhesion molecule CD44 is responsible for hyaluronan binding. Only 0.5% of the total amount of labeled hyaluronan added to the cultures was degraded during a period of 16 h. The hormone positive receptor cell lines, MCF-5, Zr-5-1 and Zr-5-1 Dox synthesized only minute amounts of hyaluronan and did not bind hyaluronan or express CD44 receptors. Expression of CD44-related hyaluronan receptors and synthesized hyaluronan may endow hormone receptor negative cells with a highly hydrated environment that facilitates cell motility and invasiveness. The lack of CD44 and thereby the lack of ability to bind hyaluronan in the extracellular matrix may contribute to the non-invasive behavior of hormone positive cell lines.