Structure and function of the foregut and salivary glands of the synanthropic diplopod Urostreptus atrobrunneus (Spirostreptidae)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Bamboo overabundance alters forest structure and dynamics in the Atlantic Forest hotspot

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Partial purification and properties of cellulase-free alkaline xylanase produced by Rhizopus stolonifer in solid-state fermentation

Rhizopus stolonifer was cultivated in wheat bran to produce a cellulase-free alkaline xylanase. The purified enzyme obtained after molecular exclusion chromatography in Sephacryl S-200 HR showed optimum temperature as 45 degrees C and hydrolysis pHs optima as pH 6.0 and 9.0. Xylanase presented higher Vmax at pH 9.0 (0.87 mu mol/mg protein) than at pH 6.0 and minor Km at pH 6.0 (7.42 mg/mL)than at pH 9.0.

Purification and properties of an alkaline protease of Aspergillus clavatus

An extracellular alkaline serine protease has been purified from a strain of Aspergillus clavatus, to apparent homogeneity, by ammonium sulfate precipitation and chromatography on Sephadex G-75. Its molar mass, estimated by SDS-PAGE, was 35 kDa. Maximum protease activity was observed at pH 9.5 and 40 degrees C. The enzyme was active between pH 6.0 and 11.0 and was found to be unstable up to 50 degrees C. Calcium at 5 mM increased its thermal stability. The protease was strongly inhibited by PMSF and chymostatin as well as by SDS, Tween 80 and carbonate ion. Substrate specificity was observed with N-p-Tos-Gly-Pro-Arg-p-nitroanilide and N-Suc-Ala-Ala-Ala-p-nitroanilide being active substates. Parts of the amino acid sequence were up to 81% homologous with those of several fungal alkaline serine proteases.

Production, characterization, and properties of beta-glucosidase and beta-xylosidase from a strain of Aureobasidium sp.

beta-Glucosidase and beta-xylosidase production by a yeastlike Aureobasidium sp. was carried out during solid-state and submerged fermentation using different carbon sources and crude enzymes were characterized. beta-Glucosidase and beta-xylosidase exhibited optimum activities at pH 2.0-2.5 and 3.0, respectively. These enzymes had the maximum activities at 65degreesC and were stable in a wide pH range and at high temperatures.

Food bodies in Cissus verticillata (Vitaceae): ontogenesis, structure and functional aspects

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Structure and dynamics of a Cariniana estrellensis (Lecythidaceae) population in a fragment of Atlantic Forest in Minas Gerais, Brazil

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Fish assemblage structure and aquatic pollution in a Brazilian stream: some limitations of diversity indices and models for environmental impact studies

The aim of this study was to describe and quantify the effect of aquatic pollution on the fish assemblage structure of the Corumbatai River (Brazil), by comparing two sites with different water quality characteristics. The results revealed that abundance of individuals was low at the polluted site (B). However, the two sites did not differ significantly in species richness (total and average). This fact contradicts theories stating that portions where the transverse area of the channel is larger should present a higher biological richness. It was also observed that the ichthyofauna of site B had higher evenness, and, consequently, a tendency to a higher diversity than that at site A. This demonstrates that diversity estimates should be used cautiously in environmental impact studies, as they do not necessarily indicate better conditions of communities living in more preserved environments.

Structural basis for branching-enzyme activity of glycoside hydrolase family 57: Structure and stability studies of a novel branching enzyme from the hyperthermophilic archaeon Thermococcus Kodakaraensis KOD1

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Structure and composition of the stream ichthyofauna of four tributary rivers of the upper Rio Parana basin, Brazil

The ichthyofauna of 24 stretches of streams, all of 100 m length and of fifth or lower order and most of second and third order, were sampled along four left bank tributaries (Rio do Peixe, Rio Aguapei, Rio Sao Jose dos Dourados, lower Rio Tiete of the main channel of the Rio Parana in the state of São Paulo, southeastern Brazil. Sampling of the fish fauna at each of the six sites in the four basins incorporated a standardized fish collecting methodology and a standardized documentation of environmental data serving as the basis for a comparative analysis of the collecting locations. The 8,189 fish specimens collected represented six orders, 18 families, 42 genera, and 56 species, with a total biomass of 28.8 kg. Approximately 52% of the collected species were characiforms, 28% siluriforms, 9% gymnotiforms, 5% cyprinodontiforms, 4% perciforms, and 2% synbranchiforms. The most abundant of the species were the characiforms Astyanax altiparanae (15% of total) and Knodus moenkhausii (12% of total). The two species with the largest overall biomasses were A. altiparanae (34% of total biomass) and the siluriform Hypostomus sp. (8% of total biomass). Analysis of the trophic structure of the studied ichthyofauna indicated that the 10 numerically dominant species across the 24 sampled streams can be grouped into five guilds that are in decreasing order of numerical importance: omnivores, insectivores, insectivores/invertivores, periphytivores, and algivores. Species richness in the sampled stream stretches varied from six to 20 species with an average richness of 14. The species richness estimated by extrapolation for all 24 sampled stream stretches was 67 species. The Characidae are predominant among the collected specimens with approximately 50% of both individuals and biomass, a fact hypothesized to be a function of several attributes typical of the family. Six of the 56 collected species were new to science and six other species are of indefinite taxonomic status and require further analysis in order to determine their identity.

Structure and feeding of a stream fish assemblage in southeastern Brazil: evidence of low seasonal influences

Aim: The present study was developed in a deforested stream located in a region that exhibits marked seasonality with the purpose to investigate whether ecological descriptors of the quantitative structure (i.e., composition, abundance, biomass, species richness, diversity) and feeding of fishes do change between the dry and wet periods. Methods: Sampling was conducted bimonthly from April 2004 to February 2005 by using a standardized effort with electrofishing equipment and environmental variables measurements. Results: We collected 713 fishes belonging to 23 species. The most abundant species were Gymnotus carapo (24.0%) and Poecilia reticulata (23.8%). Species richness, abundance, and biomass showed to be higher in the wet period, but these differences were not significant and did not influence the multivariate pattern of the assemblage (ANOSIM, R = 0.148). Nevertheless, average dissimilarity between community structure in the dry and wet periods was 52.7%, mainly due to the differential contribution of P. reticulata, notably more abundant in the wet season, under quasi-hypoxic water conditions. Examination of 333 gastric contents of 12 species evidenced that food variety was higher in the dry period. of these species, 67% (Astyanax altiparanae, Astyanax fasciatus, Geophagus brasiliensis, Gymnotus carapo, Hypostomus ancistroides, Phalloceros harpagos, Poecilia reticulata, and Rhamdia quelen) kept the diet throughout the year, being classified in the same trophic groups in both periods, and detritus was the most important item for half of them, followed by aquatic insects. Overall, no significant differences in the community's diet between periods were registered (ANOSIM, R = [long dash]0.04). Conclusions: This relative constancy suggests a quite regular availability of resources (mainly shelters in submerged marginal grasses and detritus) along the year.

Electromagnetic structure and weak decay of meson K in a light-front QCD-inspired model

The kaon electromagnetic (e.m.) form factor is reviewed considering a light-front constituent quark model. In this approach, it is discussed the relevance of the quark-antiquark pair terms for the full covariance of the e.m. current. It is also verified, by considering a QCD dynamical model, that a good agreement with experimental data can be obtained for the kaon weak decay constant once a probability of about 80% of the valence component is taken into account.

Electromagnetic structure and weak decay of pseudoscalar mesons in a light-front QCD-inspired model

We study the scaling of the S-3(1)-S-1(0) meson mass splitting and the pseudoscalar weak-decay constants with the mass of the meson, as seen in the available experimental data. We use an effective light-front QCD-inspired dynamical model regulated at short distances to describe the valence component of the pseudoscalar mesons. The experimentally known values of the mass splitting, decay constants (from global lattice-QCD averages) and the pion charge form factor up to 4 [GeV/c](2) are reasonably described by the model.

Observation and properties of the X(3872) decaying to J/psi pi(+)pi(-) in p(p)over-bar collisions at root s=1.96 TeV

We report the observation of the X(3872) in the J/psipi(+)pi(-) channel, with J/psi decaying to mu(+)mu(-), in p (p) over bar collisions at roots=1.96 TeV. Using approximately 230 pb(-1) of data collected with the Run II D0 detector, we observe 522+/-100 X(3872) candidates. The mass difference between the X(3872) state and the J/psi is measured to be 774.9+/-3.1(stat)+/-3.0(syst) MeV/c(2). We have investigated the production and decay characteristics of the X(3872) and find them to be similar to those of the psi(2S) state.

Observation and properties of the orbitally excited B-s2* meson

We report the direct observation of the excited L=1 state B-s2* in fully reconstructed decays to B+K-. The mass of the B-s2* meson is measured to be 5839.6 +/- 1.1(stat)+/- 0.7(syst) MeV/c(2), and its production rate relative to the B+ meson is measured to be [1.15 +/- 0.23(stat)+/- 0.13(syst)]%.