The nematofauna from the seaweeds Sargassum polyceratium Montagne, Hypnea musciformis Ku¨etzing, Padina gymnospora Ku¨etzing and the seagrass Halodule wrightii Ascherson was studied in March 2001, at Pedra do Xare´u, Pernambuco, Brazil, in order to investigate the associations of organisms, as well as the relation between the plant architecture and the associated fauna. Soft sediments adjacent to phytal environments were also investigated. Thirty-eight genera were found, including two new records (Odontanticoma sp. and Wieseria sp.) for the Brazilian coast. Multivariate analyses were carried out in order to verify the relation between nematode assemblages on plants and in sediments. The results showed that these assemblages were different in structure and composition between macrophytes and sediments. They were different in structure but not in composition among macrophytes, so the nematode biodiversity was related to the structural features of macrophytes' habitats.
The phosphodiesterase type 5 (PDE5) inhibitor, Sildenafil, is a novel, oral treatment approach for pulmonary hypertension. As Leydig cells present PDE5, this study was conducted to investigate the effects of the chronic treatment with Sildenafil (25 mg/kg) on male Swiss Webster mice steroidogenesis. After a 4-week long experimental design, Leydig cells were analysed by morphological and immunocytochemical procedures. Serum testosterone was assayed by radioimmunoassay. Leydig cells presented noteworthy ultrastructural alterations, such as a vesicular smooth endoplasmic reticulum, large vacuoles scattered through the cytoplasm, enlarged mitochondria with discontinue cristaes and whorle membranes with vesicles at the periphery, which are typical characteristics of an activated steroid-secreting cell. Important immunocytochemical labelling for steroidogenic acute regulatory protein, cytochrome P450 side-chain cleavage enzyme and testosterone were detected in isolated Leydig cells. In addition, Sildenafil-treated mice showed significant increased levels of total testosterone. The results obtained in the present study are consistent with the hypothesis that the accumulation of cyclic guanosine monophosphate by PDE5 inhibition could be involved in the androgen biosynthesis stimulation. Important clinical implications of hormonal disorders should be taken into account for patients with pulmonary hypertension.
The distribution, population dynamics and secondary production of the polychaete Euzonus furciferus was studied in Atami Beach (Southern Brazil), from February 1992 to March 1993. Euzonus furciferus Ehlers, 1897 is the only deposit feeder species of the upper intertidal region. The organisms were present in the sandy beach all over the year, concentrated in a narrow band, and reaching maximal densities of 3,029 individuals m-2. Peaks of abundance occurred in September 1992, with a mean of 681.8 individuals m-2. Recruitment occurred in winter, with a peak in July. Mean annual biomass was estimated in 0.218 gAFDW m-2, with a total annual production of 0.466 gAFDW m-2 y-1, giving a P/B ratio of 2.13 y-1. Similar values were found for a filter-feeder polychaete inhabiting the same beach, suggesting that general food disposability of each particular environment is more important for production than the trophic strategic employed by those organisms exploring this environment.
Neotropical Entomology 36 (6):966-971 (2007) Eclosão, Desenvolvimento e Sobrevivência de Aedes albopictus (Skuse) (Diptera: Culicidae) sob Diferentes Condições de Temperatura da Água RESUMO -Em áreas tropicais, onde as populações de insetos vetores são particularmente abundantes, as temperatura usualmente variam entre 25°C e 35°C. Considerando a importância dessa variação na determinação da dinâmica populacional de mosquitos, neste trabalho, desenvolvimento e as taxas de eclosão e sobrevivência dos estágios imaturos de Aedes albopictus (Skuse) foram comparados sob temperaturas constantes de 25, 30 e 35°C (em câmaras climatizadas) e ambientes (25°C a 29°C). A taxa de eclosão foi considerada como o total de larvas obtidas após 24h. O período de desenvolvimento, assim como a taxa de sobrevivência larval e pupal foram avaliados diariamente. A taxa de eclosão foi signifi cativamente mais elevada sob temperatura ambiente comparada às constantes, sugerindo que a variação da temperatura pode ser um fator estimulante da eclosão. O tempo médio de eclosão aumentou com a temperatura, variando de 2,8h (25ºC) a 5,2h (35ºC). A duração do período larval apresentou grande variabilidade dentro de cada grupo, embora não tenha diferido signifi cativamente entre os mesmos (11,0 ± 4,19 dias), tendo sido mais longo para indivíduos mantidos na água a 35°C (12,0 ± 4,95 dias) e temperatura ambiente (13,6 ± 5,98 dias). Ao contrário, a sobrevivência das larvas foi fortemente afetada na temperatura mais elevada, onde apenas um indivíduo alcançou o estágio adulto. Esses resultados sugerem que a população de Ae. albopictus de Recife pode estar em processo de adaptação ao aumento de temperatura e que o limite para o desenvolvimento de estágios larvais se encontra próximo a 35°C.
PALAVRAS-CHAVE: Biologia, vetor, ciclo de vida, limite térmicoABSTRACT -In tropical areas, where vector insects populations are particularly numerous, temperature usually range between 25°C and 35°C. Considering the importance of such temperature variation in determining mosquitoes population dynamics, in this work the developmental, eclosion and survival rates of the immature stages of Aedes albopictus (Skuse) were compared under constant 25, 30 and 35°C (using acclimatized chambers) and environmental (25°C to 29°C) temperatures. The hatching rate was considered as total number of larvae recovered after 24h. The development period as well as larval and pupal survival rate were evaluated daily. Eclosion rate was signifi cantly higher under environmental temperature than under the studied constant temperatures, suggesting that temperature variation may be an eclosion-stimulating factor. The mean eclosion time increased with the temperature, ranging from 2.8h (25°C) to 5.2h (35°C). The larval period was greatly variable inside each group, although it did not differ signifi cantly amongst groups (11.0 ± 4.19 days), with individuals showing longer larval stages in water at 35°C (12.0 ± 4.95 days) and environmental temperature (13.6 ± 5.98 days). Oppositely, survival was...
Sandy beaches constitute a key ecosystem and provide socioeconomic goods and services, thereby playing an important role in the maintenance of human populations and in biodiversity conservation. Despite the ecological and social importance of these ecosytems, Brazilian sandy beaches are significantly impacted by human interference, chemical and organic pollution and tourism, as well as global climate change. These factors drive the need to better understand the environmental change and its consequences for biota. To promote the implementation of integrated studies to detect the effects of regional and global environmental change on beaches and on other benthic habitats of the Brazilian coast, Brazilian marine researchers have established The Coastal Benthic Habitats Monitoring Network (ReBentos). In order to provide input for sample planning by ReBentos, we have conducted an intensive review of the studies conducted on Brazilian beaches and summarized the current knowledge about this environment. In this paper, we present the results of this review and describe the physical, biological and socioeconomics features of Brazilian beaches. We have used these results, our personal experience and worldwide literature to identify research projects that should be prioritized in the assessment of regional and global change on Brazilian sandy beaches. We trust that this paper will provide insights for future studies and represent a significant step towards the conservation of Brazilian beaches and their biodiversity.
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