MedWorm.com provides a medical RSS filtering service. Over 6000 RSS medical sources are combined and output via different filters. This feed contains the latest items from the 'Revista Brasileira de Biologia' source. Sat, 10 Oct 2009 19:36:49 +0100 http://www.medworm.com/index.php?rid=2503853&cid=s_37482_62_f&fid=37482&url=http%3A%2F%2Fwww.scielo.br%2Fscielo.php%3Fscript%3Dsci_arttext%26pid%3DS0034-71082001000200019%26lng%3Den%26nrm%3Diso%26tlng%3Den The objective of the present study was to adapt techniques for the histological processing of Dugesiidae cocoons for the study of embryo development. The cocoons were fixed with formalin, SUSA, Bouin or paraformaldehyde/glutaraldehyde and subsequently embedded in Paraplast or glycol methacrylate (Historesin). Paraplast embedding yielded reasonable results only after the cocoon was perforated or fixed for a prolonged period of time using softening techniques with acid solutions. When the SUSA or Bouin fixative and Historesin embedding techniques were used the results were good for light microscopical analysis. Fixation with paraformaldehyde/glutaraldehyde and glycol methacrylate embedding resulted in better tissue preservation, and did not require prolonged fixation or softening techniques.... Revista Brasileira de Biologia journals http://www.medworm.com/rss/comments.php?id=2503853 Thu, 25 Jun 2009 08:48:25 +0100 2503853 http://www.medworm.com/index.php?rid=2503852&cid=s_37482_62_f&fid=37482&url=http%3A%2F%2Fwww.scielo.br%2Fscielo.php%3Fscript%3Dsci_arttext%26pid%3DS0034-71082001000200018%26lng%3Den%26nrm%3Diso%26tlng%3Den To investigate the influence of the pineal gland through melatonin secretion on the physiological and morphological parameters of pancreatic islets, we studied the plasma biochemistry and morphological and morphometric characteristics of the endocrine pancreas of male Wistar rats. The animals were distributed into five groups of ten rats each: NC - normal control group; NS - sham-operated group; Px (25) - pinealectomised group, studied 15-25 days after surgery; Px (70) - pinealectomised group, studied 60-70 days after surgery; ALX - alloxan monohydrate-treated group. Data are analyzed statistically by ANOVA and by the Kruskal-Wallis test. Although there was no significant difference in plasma glucose or insulin levels between the Px (25), Px (70) and NC groups, Px (25) animals showed a ten... Revista Brasileira de Biologia journals http://www.medworm.com/rss/comments.php?id=2503852 Thu, 25 Jun 2009 08:48:25 +0100 2503852 http://www.medworm.com/index.php?rid=2503851&cid=s_37482_62_f&fid=37482&url=http%3A%2F%2Fwww.scielo.br%2Fscielo.php%3Fscript%3Dsci_arttext%26pid%3DS0034-71082001000200017%26lng%3Den%26nrm%3Diso%26tlng%3Den Three tinctures samples from extracts of the popular medicinal plant Thuya occidentalis were tested in vitro through two short term tests for measuring the activity of genotoxic chemicals. Using the Salmonella/mammalian-microsome (Mutatest) assay and the SOS-chromotest (induction of beta-galactosidase in Escherichia coli), none of the extract was effective in inducing mutagenesis or beta-galactosidase synthesis (as an indicator of general and early sign of DNA damage), even with metabolization.Três amostras de tinturas de extratos da planta Thuya occidentalis, utilizada em medicina popular, foram testadas in vitro por meio de dois testes rápidos para medida da atividade genotóxica de químicos. Utilizando o teste de Ames (Mutateste) e o SOS-cromoteste (indução de beta-galactosidase em... Revista Brasileira de Biologia journals http://www.medworm.com/rss/comments.php?id=2503851 Thu, 25 Jun 2009 08:48:25 +0100 2503851 http://www.medworm.com/index.php?rid=2503850&cid=s_37482_62_f&fid=37482&url=http%3A%2F%2Fwww.scielo.br%2Fscielo.php%3Fscript%3Dsci_arttext%26pid%3DS0034-71082001000200016%26lng%3Den%26nrm%3Diso%26tlng%3Den Three options of water temperatures in a thermal gradient that changed from 22 to 35°C were offered to Pantanal caiman (Caiman croocodilus yacare) hatchlings. Animals from two nests were submitted to temperatures during 19 days (Nest 1 - 20 caimans caught in the nature hours after hatching), corresponding to 1 to 7 observations periods, and 13 days (Nest 2 - 20 animals obtained by artificial incubation) relative to observation period 8. Caimans remain fasting during experimental period. Hatchlings were allocated in a enclosure containing three styrofoam boxes (120 L) disposed side by side enclosed by wire netting and filled with water to the top. Thus, the animals were free to access the boxes, which temperatures were changed at the end of each observation period to avoid position effects... Revista Brasileira de Biologia journals http://www.medworm.com/rss/comments.php?id=2503850 Thu, 25 Jun 2009 08:48:25 +0100 2503850 http://www.medworm.com/index.php?rid=2503849&cid=s_37482_62_f&fid=37482&url=http%3A%2F%2Fwww.scielo.br%2Fscielo.php%3Fscript%3Dsci_arttext%26pid%3DS0034-71082001000200015%26lng%3Den%26nrm%3Diso%26tlng%3Den I studied the existence of sentinels in Saltator atricollis in a 'campo-cerrado' (Brazilian savanna) during the breeding seasons of 1994-95 and 1995-96. Groups of this species consisted of two to seven birds (N = 25). Sentinels were present (mean ± sd) 62% ± 9% of the time, and most sentinel bouts lasted from less than one to six minutes (although in some occasions for more than 30 min.). Overlap of two or more sentinels occurred on average only 3.2% of the time with birds on guard. Sentinels commonly gave contact calls in the beginning and/or at the end of a sentinel bout. The group size had no effect on time with sentinels. However the encounter rate between raptors and groups significantly influenced the time guarded. The results of this study suggests that the ability of sentinels to... Revista Brasileira de Biologia journals http://www.medworm.com/rss/comments.php?id=2503849 Thu, 25 Jun 2009 08:48:25 +0100 2503849 http://www.medworm.com/index.php?rid=2503848&cid=s_37482_62_f&fid=37482&url=http%3A%2F%2Fwww.scielo.br%2Fscielo.php%3Fscript%3Dsci_arttext%26pid%3DS0034-71082001000200014%26lng%3Den%26nrm%3Diso%26tlng%3Den Nectar of nocturnal flowers may be used by diurnal species that occasionally accomplish secondary pollination. Thirteen bird species visited Caryocar brasiliense flowers in central Brazil. There is a temporal separation between nectarivores and non-nectarivores species. Nectarivores birds visited flowers late in the morning, while other species appear earlier. C. brasiliense nectar may be an alternative resource to birds visitors during the dry season.O néctar de flores noturnas pode ser utilizado por uma fauna diurna. As flores de Caryocar brasiliense foram visitadas por 13 espécies de aves, no Brasil central. Há uma distribuição temporal entre nectarívoros e não-nectarívoros. Aves nectarívoras concentram suas visitas no final da manhã e à tarde, outras aves, no início da manh... Revista Brasileira de Biologia journals http://www.medworm.com/rss/comments.php?id=2503848 Thu, 25 Jun 2009 08:48:25 +0100 2503848 http://www.medworm.com/index.php?rid=2503847&cid=s_37482_62_f&fid=37482&url=http%3A%2F%2Fwww.scielo.br%2Fscielo.php%3Fscript%3Dsci_arttext%26pid%3DS0034-71082001000200013%26lng%3Den%26nrm%3Diso%26tlng%3Den The present work studied helminth parasites of "pacu-manteiga", Myleus tiete (Osteichthyes: Characidae) from Volta Grande Reservoir, MG, Brazil. Fishes with 142.6 ± 24.7 g weight and 17.3 ± 1.0 cm total length were collected. Five out six analysed fish (prevalence 83.3%) were parasitized in the intestine with an average of 535.6 ± 334.6 oxyurid nematodes per fish. The helminth was identified as Ichthyouris voltagrandensis n.sp. (Nematoda: Pharyngodonidae). It differs from I. brasiliensis (Moravec et al., 1992a) by the absence of lateral alae, higher measures of tail and caudal alae of males, esophageal isthmus length, distance of excretory pore from anterior end and spicule length. In addition, eggs were provided by two long filaments in just one pole and by the first time the authors o... Revista Brasileira de Biologia journals http://www.medworm.com/rss/comments.php?id=2503847 Thu, 25 Jun 2009 08:48:25 +0100 2503847 http://www.medworm.com/index.php?rid=2503846&cid=s_37482_62_f&fid=37482&url=http%3A%2F%2Fwww.scielo.br%2Fscielo.php%3Fscript%3Dsci_arttext%26pid%3DS0034-71082001000200012%26lng%3Den%26nrm%3Diso%26tlng%3Den The distribution and abundance of aquatic insects were studied in the longitudinal gradient of the watershed of Macaé River, a coastal Atlantic Forest river in South-eastern Brazil. Sampling stations were selected in the first, second, fourth, fifth, and sixth orders and sampled in April, July, and October 1995. This represented the end of the rainy season, the dry season, and the beginning of another rainy season, respectively. In each month four samples were collected using a Surber sampler from each of the following substrates: sand, litter deposited in pool areas, litter in riffle areas, and stones. A total of 46,431 specimens of aquatic insects belonging to ten orders were obtained. The data were analyzed by the multivariate methodologies of Correspondence Analysis (CA) and Cluster A... Revista Brasileira de Biologia journals http://www.medworm.com/rss/comments.php?id=2503846 Thu, 25 Jun 2009 08:48:25 +0100 2503846 http://www.medworm.com/index.php?rid=2503845&cid=s_37482_62_f&fid=37482&url=http%3A%2F%2Fwww.scielo.br%2Fscielo.php%3Fscript%3Dsci_arttext%26pid%3DS0034-71082001000200011%26lng%3Den%26nrm%3Diso%26tlng%3Den We analyzed the thermal ecology and activity patterns of the lizard community from the Restinga of Jurubatiba, Rio de Janeiro, Brazil. The broadest activity was that of Tropidurus torquatus, a sit-and-wait forager, while the active foraging teiid Cnemidophorus littoralis had the shortest activity. The nocturnal gekkonid Hemidactylus mabouia was found active during the day only during early morning and late afternoon, when environmental temperatures are low. Body temperature was highest for Cnemidophorus littoralis and lowest for the two Mabuya species. The patterns found here are discussed and compared to those of congeneric species in other habitats in Brazil.Foram analizados a ecologia termal e os padrões de atividade da comunidade de lagartos da restinga de Jurubatiba, Rio de Janeiro, ... Revista Brasileira de Biologia journals http://www.medworm.com/rss/comments.php?id=2503845 Thu, 25 Jun 2009 08:48:25 +0100 2503845 http://www.medworm.com/index.php?rid=2503844&cid=s_37482_62_f&fid=37482&url=http%3A%2F%2Fwww.scielo.br%2Fscielo.php%3Fscript%3Dsci_arttext%26pid%3DS0034-71082001000200010%26lng%3Den%26nrm%3Diso%26tlng%3Den Four size fractions of the sediment of six environments of the upper Paraná River floodplain were analyzed for carbon, nitrogen, and phosphorus contents and microbial respiration (oxygen consumption). Particle size did not affect nitrogen and phosphorus content or microbial activity, but did affect carbon content (F = 4.274, df = 3; 20, p = 0.020). The carbon concentration of ultra-fine particles was significantly lower than that of other sizes of sediment particles. Microbial respiration values were well predicted by sediment chemical composition, as shown by multiple regression (microbial respiration = -0.39 - 0.210C + 0.108N + 0.796P; F = 7.0495, p = 0.0022). However, phosphorus was the element which best explained the microbial respiration (partial coefficient = 0.796, p = 0.0039, n =... Revista Brasileira de Biologia journals http://www.medworm.com/rss/comments.php?id=2503844 Thu, 25 Jun 2009 08:48:25 +0100 2503844 http://www.medworm.com/index.php?rid=2503843&cid=s_37482_62_f&fid=37482&url=http%3A%2F%2Fwww.scielo.br%2Fscielo.php%3Fscript%3Dsci_arttext%26pid%3DS0034-71082001000200009%26lng%3Den%26nrm%3Diso%26tlng%3Den Diet of 364 specimens of the dourado (Salminus maxillosus) was studied monthly at Cachoeira das Emas from November/1996 to May/1998, considered the breeding ground of this and other migrant fishes of Mogi-Guaçu River. Only adults were found at this site, and diet consisted exclusively of fish, with predominance of Leporinus sp. Seasonal variation in feeding activity was highest during some months of the rainy and hot season (September-December), when fish composition and number of prey species consumed also changed. These modifications were primarily attributed to an increase in food availability at the site of study during the rainy season, once most of the migrant species, including small Characidae concentrate there at this time of year. Apparently diet shifts, prey availability and ra... Revista Brasileira de Biologia journals http://www.medworm.com/rss/comments.php?id=2503843 Thu, 25 Jun 2009 08:48:25 +0100 2503843 http://www.medworm.com/index.php?rid=2503842&cid=s_37482_62_f&fid=37482&url=http%3A%2F%2Fwww.scielo.br%2Fscielo.php%3Fscript%3Dsci_arttext%26pid%3DS0034-71082001000200008%26lng%3Den%26nrm%3Diso%26tlng%3Den The assessment of the diversity of habitats and the characterisation of the functional trophic groups of benthic macroinvertebrate communities of some rivers of Serra do Cipó (MG) were the main objectives of this study. The available trophic resources and the types of substrata were characterised along with the structure and composition of their using functional trophic groups. Serra do Cipó is a watershed divisor of the São Francisco and Doce River basins, including a series of streams and rivers, of good water quality and well preserved ecological characteristics. Samples were collected in Cipó, Peixe and Preto do Itambé rivers, besides the Indaiá and Capão da Mata streams at 26 sampling stations, during the rainy (February) and dry (October) seasons of 1998, using "Kicking nets" ... Revista Brasileira de Biologia journals http://www.medworm.com/rss/comments.php?id=2503842 Thu, 25 Jun 2009 08:48:25 +0100 2503842 http://www.medworm.com/index.php?rid=2503841&cid=s_37482_62_f&fid=37482&url=http%3A%2F%2Fwww.scielo.br%2Fscielo.php%3Fscript%3Dsci_arttext%26pid%3DS0034-71082001000200007%26lng%3Den%26nrm%3Diso%26tlng%3Den Diversity and habitat preference of macroinvertebrates were studied in Macaé River basin, Rio de Janeiro State, Brazil, along its longitudinal gradient. We selected stream reaches corresponding to 1st, 2nd, 4th, 5th and 6th orders. A Surber sampler was used to collect four macroinvertebrates samples of each substrate (sand, litter in pool areas, stones, and litter in riffle areas) during the three sampling periods, defined based on the rain regime: April (end of the rainy season), July (dry season), and October (beginning of the rainy season). We identified 46,431 specimens corresponding to 117 taxa. Analysis of diversity numbers (both for family or genus level) indicated that all insect taxonomic orders had higher numbers on 2nd order stream reach, except for Ephemeroptera, on 4th order.... Revista Brasileira de Biologia journals http://www.medworm.com/rss/comments.php?id=2503841 Thu, 25 Jun 2009 08:48:25 +0100 2503841 http://www.medworm.com/index.php?rid=2503840&cid=s_37482_62_f&fid=37482&url=http%3A%2F%2Fwww.scielo.br%2Fscielo.php%3Fscript%3Dsci_arttext%26pid%3DS0034-71082001000200006%26lng%3Den%26nrm%3Diso%26tlng%3Den Five lotic systems of Serra do Cipó, south-east Brazil, were investigated in order to assess the existing diversity of benthic macroinvertebrates, habitats-microhabitats, and the available trophic resources. For each river it was analysed the communities of benthic macroinvertebrates and the composition of some taxonomic groups (Plecoptera, Ephemeroptera, Trichoptera and Diptera Chironomidae): the community with Bivalvia Sphaeriidae, Oligochaeta and Ephemeroptera Baetidae (being supposed a closed relation Bivalvia-Oligochaeta based on the process of bioturbation and enrichment of sediment in organic matter) in Tanque River; the macrofauna associated to aquatic macrophytes from rivers Peixe and Preto do Itambé reflecting the reaction of the ecosystems versus the quantities of nutrients wh... Revista Brasileira de Biologia journals http://www.medworm.com/rss/comments.php?id=2503840 Thu, 25 Jun 2009 08:48:25 +0100 2503840 http://www.medworm.com/index.php?rid=2503839&cid=s_37482_62_f&fid=37482&url=http%3A%2F%2Fwww.scielo.br%2Fscielo.php%3Fscript%3Dsci_arttext%26pid%3DS0034-71082001000200005%26lng%3Den%26nrm%3Diso%26tlng%3Den The feeding habits of Rioraja agassizii (syn. Raja agassizii) and Psammobatis extenta (syn. Psammobatis glansdissimilis) of the South-eastern Brazilian coast were studied by means of stomach content analysis. The samples were obtained on eight seasonal oceanographic cruises, carried out between October 1985 and July 1987. The importance of each food item was evaluated on the basis of the Index of Relative Importance and the feeding similarity by Percentage of Similarity. The results indicated that both species are benthic feeders, preying mainly on Crustacea, especially Amphipoda, Caridea and Brachyura. Teleostei were also important for R. agassizii. Seasonal variation of the diet seems to be associated with the availability of the prey, whose distribution and abundance are related to the ... Revista Brasileira de Biologia journals http://www.medworm.com/rss/comments.php?id=2503839 Thu, 25 Jun 2009 08:48:25 +0100 2503839 http://www.medworm.com/index.php?rid=2503838&cid=s_37482_62_f&fid=37482&url=http%3A%2F%2Fwww.scielo.br%2Fscielo.php%3Fscript%3Dsci_arttext%26pid%3DS0034-71082001000200004%26lng%3Den%26nrm%3Diso%26tlng%3Den Food habits and daily feeding activity of fish populations are important ecological variables for understanding their role in the ecosystem. Diel changes in feeding activity and dietary composition of juvenile whitemouth croaker Micropogonias furnieri, shortfin corvina Isopisthus parvipinnis, shorthead drum Larimus breviceps and of juvenile and adult banded croaker Paralonchurus brasiliensis were investigated from samples taken over a 24 hours period from 4 to 5 September 1987 on the continental shelf off South-eastern Brazil. Whitemouth croaker and banded croaker had a benthic diet based on polychaetes and some caridean shrimps and showed no diel feeding pattern. Shortfin corvina and shorthead drum fed on crustaceans and teleostean fish, the former species primarily on pelagic sergestid s... Revista Brasileira de Biologia journals http://www.medworm.com/rss/comments.php?id=2503838 Thu, 25 Jun 2009 08:48:25 +0100 2503838 http://www.medworm.com/index.php?rid=2503837&cid=s_37482_62_f&fid=37482&url=http%3A%2F%2Fwww.scielo.br%2Fscielo.php%3Fscript%3Dsci_arttext%26pid%3DS0034-71082001000200003%26lng%3Den%26nrm%3Diso%26tlng%3Den Flight activity of Plebeia pugnax Moure (in litt.) was studied in six colonies coming from Cunha, SP, from July to October 1994. Twice a week, from 8:00 a.m. to 6:00 p.m., for 5 minutes every half-hour, all the bees entering and leaving the hives were counted. Six hundred counts were made and the materials that foragers carried were recorded. Data were analysed in relation to temperature, relative humidity, light intensity and day time. Foragers' flight activity was relatively constant in a wide range of temperature, from 22°C to 34°C. The minimum temperature for the beginning of flight activity was 14°C. Effective flight activity (when foragers of all colonies were leaving the hives) occurred at 15°C. These bees also flew within a wide range of relative humidity, from 30% to 100%, dec... Revista Brasileira de Biologia journals http://www.medworm.com/rss/comments.php?id=2503837 Thu, 25 Jun 2009 08:48:25 +0100 2503837 http://www.medworm.com/index.php?rid=2503836&cid=s_37482_62_f&fid=37482&url=http%3A%2F%2Fwww.scielo.br%2Fscielo.php%3Fscript%3Dsci_arttext%26pid%3DS0034-71082001000200002%26lng%3Den%26nrm%3Diso%26tlng%3Den The capacity of a given natural ecosystem to provide certain goods and services that satisfy human needs depends on its environmental characteristics (natural processes and components). It was described the availability of these goods and services (environmental functions) controlled and sustained by ecological processes operating in Ecological Station of Jataí (Luiz Antônio, SP). The environmental functions identified were grouped in four main categories. To make environmental values an integrated factor in planning and decision making it was assessed their socio-economic importance in qualitative terms and, if possible their monetary value. The combined potential annual return from identified functions of Ecological Station of Jataí is at least US$ 708.83/ha/year. In comparison to cal... Revista Brasileira de Biologia journals http://www.medworm.com/rss/comments.php?id=2503836 Thu, 25 Jun 2009 08:48:25 +0100 2503836 http://www.medworm.com/index.php?rid=1581313&cid=s_37482_62_f&fid=37482&url=http%3A%2F%2Fwww.scielo.br%2Fscielo.php%3Fscript%3Dsci_arttext%26pid%3DS0034-71082001000200001%26lng%3Den%26nrm%3Diso%26tlng%3Den (Source: Revista Brasileira de Biologia) Revista Brasileira de Biologia journals http://www.medworm.com/rss/comments.php?id=1581313 Sat, 05 Jul 2008 15:35:11 +0100 1581313