RESUMO
Although the importance of long-term data has been emphasized by ecologists in recent years, little is known about how communities may change over time. In this study, we describe the general patterns of aquatic macrophyte diversity in the Paraná River floodplain observed during six years of study. Temporal changes in community composition were also evaluated. Data on the presence or absence of aquatic macrophytes were collected between March 2002 and March 2008, in six lakes associated with three rivers. Different analytical strategies were used to evaluate the dynamics of aquatic macrophyte communities between the different systems in the floodplain. The composition of aquatic macrophytes differed among the rivers, mainly with respect to the different vegetation life forms (floating, submersed, emergent and rooted with floating stems). The temporal similarity of species composition during the six years and the beta-diversity index indicated that the month-to-month species turnover was, in general, lower in the connected lakes, which are directly influenced by the river. Probably the water level fluctuation is a selective force that contributes to maintaining diversity or richness. Our findings indicated the importance of abiotic characteristics and connectivity of the lakes in determining macrophyte composition and community stability over a long time frame.
Assuntos
Biodiversidade , Magnoliopsida/classificação , Rios , BrasilRESUMO
Although the importance of long-term data has been emphasized by ecologists in recent years, little is known about how communities may change over time. In this study, we describe the general patterns of aquatic macrophyte diversity in the Paraná River floodplain observed during six years of study. Temporal changes in community composition were also evaluated. Data on the presence or absence of aquatic macrophytes were collected between March 2002 and March 2008, in six lakes associated with three rivers. Different analytical strategies were used to evaluate the dynamics of aquatic macrophyte communities between the different systems in the floodplain. The composition of aquatic macrophytes differed among the rivers, mainly with respect to the different vegetation life forms (floating, submersed, emergent and rooted with floating stems). The temporal similarity of species composition during the six years and the beta-diversity index indicated that the month-to-month species turnover was, in general, lower in the connected lakes, which are directly influenced by the river. Probably the water level fluctuation is a selective force that contributes to maintaining diversity or richness. Our findings indicated the importance of abiotic characteristics and connectivity of the lakes in determining macrophyte composition and community stability over a long time frame.
Estudos utilizando ampla escala temporal ainda são escassos na ecologia, mesmo considerando sua importância no estudo de comunidades. Esse trabalho teve como objetivo principal descrever padrões gerais sobre a diversidade de macrófitas aquáticas na planície de inundação do Alto Rio Paraná utilizando uma ampla escala temporal (seis anos de estudo). Mudanças na composição das comunidades ao longo do tempo também foram avaliadas. Dados de presença ou ausência de macrófitas foram obtidos entre Março de 2002 e Março de 2008 em seis lagoas associadas a três rios na planície de inundação. Diferentes técnicas foram utilizadas para avaliar a dinâmica das comunidades de macrófitas aquáticas entre os diferentes ambientes. De maneira geral, a composição das comunidades foi dissimilar entre os diferentes rios, principalmente considerando os diferentes grupos funcionais de macrófitas (flutuante livre, submersa, emergente e enraizada com folha flutuante). A similaridade temporal na composição de espécies e o índice de diversidade beta indicaram que a substituição de espécies ao longo dos meses foi, de maneira geral, menor nas lagoas conectadas ao rio principal. Provavelmente, a flutuação no nível da água representa uma pressão seletiva que ajuda a manter a diversidade de espécies nas lagoas diretamente influenciadas pelo rio. Os resultados desse estudo indicaram a importância das características abióticas e da conectividade das lagoas na composição e estabilidade temporal das comunidades de macrófitas aquáticas na planície de inundação do Alto Rio Paraná.
Assuntos
Magnoliopsida/classificação , Biodiversidade , Rios , BrasilRESUMO
Three new labdane diterpenoids, pacovatinins A-C (1-3), were isolated from seeds of the Brazilian medicinal plant Renealmia exaltata ("Pacová-catinga"), and their structures including absolute configurations were elucidated by spectroscopic data and a modified Mosher method.
Assuntos
Antineoplásicos Fitogênicos/isolamento & purificação , Diterpenos/isolamento & purificação , Plantas Medicinais/química , Animais , Antineoplásicos Fitogênicos/química , Antineoplásicos Fitogênicos/farmacologia , Brasil , Carcinoma de Células Escamosas , Diterpenos/química , Diterpenos/farmacologia , Humanos , Leucemia L1210 , Espectroscopia de Ressonância Magnética/métodos , Camundongos , Conformação Molecular , Estrutura Molecular , Sementes/química , Estereoisomerismo , Relação Estrutura-Atividade , Células Tumorais Cultivadas/efeitos dos fármacosRESUMO
In July 1996 the Washington State Department of Health (Seattle) was notified of a cluster of a flulike, rash-associated illness in a 126-member church group, many of whom were adolescents. The group had recently returned from Tecate, Mexico, where members had assisted with construction projects at an orphanage. After 1 member was diagnosed with coccidioidomycosis, we initiated a study to identify further cases. We identified 21 serologically confirmed cases of coccidioidomycosis (minimum attack rate, 17%). Twenty cases (95%) occurred in adolescents, and 13 patients (62%) had rash. Sixteen symptomatic patients saw 19 health care providers; 1 health care provider correctly diagnosed coccidioidomycosis. Coccidioides immitis was isolated from soil samples from Tecate by use of the intraperitoneal mouse inoculation method. Trip organizers were unaware of the potential for C. immitis infection. Travelers visiting regions where C. immitis is endemic should be made aware of the risk of acquiring coccidioidomycosis, and health care providers should be familiar with coccidioidomycosis and its diagnosis.
Assuntos
Coccidioides/isolamento & purificação , Coccidioidomicose/epidemiologia , Surtos de Doenças , Adolescente , Adulto , Animais , Anticorpos Antifúngicos/sangue , Coccidioidomicose/microbiologia , Coccidioidomicose/patologia , Feminino , Humanos , Masculino , México , Camundongos , Fatores de Risco , Microbiologia do Solo , Viagem , Washington/epidemiologiaRESUMO
A novel tricyclic diterpenoid antibiotic, brasilicardin A, was isolated from the culture broth of Nocardia brasiliensis IFM 0406. The antibiotic exhibited immunosuppressive activity in a mouse mixed lymphocyte reaction (MLR) assay system and its IC50 value was 0.057 microg/ml. Although the inhibitory activity of cyclosporin A (CyA) against IL-2 production was confirmed in the MLR assay system, brasilicardin A did not have the activity. The results of in vitro toxicity testing of brasilicardin A against various human cell lines were compared with those of CyA.
Assuntos
Aminoglicosídeos , Antibacterianos/farmacologia , Imunossupressores/farmacologia , Nocardia/metabolismo , Animais , Antibacterianos/biossíntese , Antibacterianos/isolamento & purificação , Bactérias/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Células Cultivadas , Cromatografia Líquida de Alta Pressão , Fermentação , Fungos/efeitos dos fármacos , Humanos , Imunofilinas/antagonistas & inibidores , Imunossupressores/isolamento & purificação , Interleucina-2/metabolismo , Teste de Cultura Mista de Linfócitos , Camundongos , Testes de Sensibilidade MicrobianaAssuntos
Alcaloides/isolamento & purificação , Antineoplásicos/isolamento & purificação , Indóis/isolamento & purificação , Nitrilas/química , Nocardia/química , Alcaloides/química , Alcaloides/farmacologia , Antineoplásicos/química , Antineoplásicos/farmacologia , Indóis/química , Indóis/farmacologia , Análise EspectralRESUMO
New benz[alpha]anthraquinone antibiotics (brasiliquinones A, B and C) with an ethyl group at C-3 were isolated. The producer was identified as Nocardia brasiliensis. The antibiotics were active against Gram-positive bacteria including Mycobacterium sp., but not active against Gram-negative bacteria or fungi. They were also active against multiple drug-resistant P388/ADR tumor cells.
Assuntos
Antibacterianos/isolamento & purificação , Nocardia/metabolismo , Animais , Antraquinonas/isolamento & purificação , Antibacterianos/química , Antibacterianos/farmacologia , Fermentação , Camundongos , Nocardia/classificação , Células Tumorais CultivadasRESUMO
A new 32-membered macrolide antibiotic, brasilinolide A was isolated from the fermentation broth of Nocardia sp. IFM 0406. The producer was identified as Nocardia brasiliensis. The antibiotic was only active against Aspergillus niger, but not active against other fungi including yeasts as well as other filamentous like fungi and bacteria. Brasilinolide A exerted an immunosuppressive activity in the assay system of a mixed lymphocyte reaction (MLR).
Assuntos
Antibacterianos/isolamento & purificação , Macrolídeos/química , Macrolídeos/isolamento & purificação , Nocardia/química , Animais , Antibacterianos/biossíntese , Antibacterianos/química , Antibacterianos/farmacologia , Bactérias/efeitos dos fármacos , Células Cultivadas/efeitos dos fármacos , Meios de Cultura , Fungos/efeitos dos fármacos , Células HeLa/efeitos dos fármacos , Humanos , Macrolídeos/farmacologia , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Nocardia/classificaçãoRESUMO
Prevalence of Strongyloides stercoralis infection in three areas of Brazil was surveyed by a recently developed faecal culture method (an agar plate culture). The Strongyloides infection was confirmed in 11.3% of 432 subjects examined. The diagnostic efficacy of the agar plate culture was as high as 93.9% compared to only 28.5% and 26.5% by the Harada-Mori filter paper culture and faecal concentration methods, when faecal samples were examined simultaneously by these three methods. Among the 49 positive samples, about 60% were confirmed to be positive only by the agar plate culture. These results indicate that the agar plate culture is a sensitive new tool for the correct diagnosis of chronic Strongyloides infection.
Assuntos
Fezes/parasitologia , Strongyloides stercoralis/isolamento & purificação , Estrongiloidíase/diagnóstico , Estrongiloidíase/epidemiologia , Adolescente , Ágar , Animais , Brasil/epidemiologia , Meios de Cultura , Feminino , Helmintos/isolamento & purificação , Humanos , Masculino , PrevalênciaRESUMO
To determine the efficacy of stool examination for detection of Strongyloides infection, 1,350 stool samples collected in Japan, Brazil, and Thailand were examined by four different methods (direct fecal smear, formalin-ether concentration. Harada-Mori filter paper culture, and agar plate culture). The newly developed agar plate culture method was highly effective; more than 96% of the positive cases were diagnosed by this method. The coprologic examination, however, was not sensitive enough for detecting chronic infections because more than 40% of the positive cases were overlooked even when persons with proven Strongyloides infection were re-examined several months later without intervening treatment. Therefore, it is essential to examine stool samples repeatedly to achieve a correct diagnosis, and even so, it is important to note that a negative result does not necessarily indicate the unequivocal absence of the infection.