Morphological and histochemical study of the myotomal muscle in pacu (Piaractus mesopotamicus Holmberg, 1887) during the initial growth phases

Morphological and histochemical methods were used to evaluate the myotomal muscle characteristics of pacu (Piaractus mesopotamicus) from hatching to 40 days old. During the larval period, the musculature consisted predominantly of white muscle. White and red muscle mass increased at 10, 20, 30 and 40 days after hatching. The larvae had round muscle fibers with a moderate degree of maturation and central nuclei. In subsequent phases, small and immature fibers were visible near larger and more differentiated fibers. Undifferentiated cells or presumptive myoblasts located in embryogenic zones were visible in the dorsal and ventral regions, and were more evident at 30 and 40 days. The red muscle fibers located in the subdermal region, had oxidative metabolism and slow contraction, whereas the more predominant white muscle fibers had glycolytic metabolism and fast contraction. Our findings indicate that during the initial phases, myotomal muscle growth in pacu occurs by both, muscle fiber hypertrophy and hyperplasia. The analysis of frequency of red and white muscle fibers shows that hyperplastic growth is intense in this period. As the growth rate in adult fish is related to the number of muscle fibers in young fish, extrinsic factors could change the muscle fiber phenotype and influence their ultimate size.

Influence of light quality on germination and initial growth of canephori seedlings Peltophorum dubium (Sprenge) Taub.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Peanut genes identified during initial phase of Cercosporidium personatum infection

Late leaf spot (LLS), caused by the fun.-us Cercosporidium personatum, is one of the most severe diseases in peanut (Arachis hypogaea). The vast majority of commercial cultivars do not exhibit satisfactory levels of resistance to the pathogen, whereas non-commercial genotypes cv. 850 and cv. 909 are resistant to LLS and show symptoms similar to hypersensitive response (HR) lesions. In the present study, we investigated the molecular components of the initial stages of the resistance by gene expression profiling using suppression subtractive hybridization and differential screening of cDNA macroarray techniques. Gene expression analyses have allowed us to identify more than 700 peanut unique expressed sequence taus (EST) involved in several aspects of the early stages of C. personatum pathogenesis, such as components of defense signaling pathways, gene expression regulators, cell cycle controlling genes and components of the biosynthesis of transducer and antimicrobial compounds. The most significantly induced gene corresponds to a novel O'-methyltranferase, suggesting its involvement in the production of local lesions in C. personatum-resistant A. hypogea genotypes. Taken together, our results contribute to elucidate the defense strategies of peanut and provide the framework for the generation of pathogen-resistant peanut cultivars. (C) 2007 Elsevier B.V. All rights reserved.

The influence of initial feeding on muscle development and growth in pacu Piaractus mesopotamicus larvae

The effects of different feeding schemes on pacu Piaractus mesopotamicus early development were evaluated with respect to growth, survival, muscle development, and differential gene expression of MyoD and myogenin. The pacu larvae (4 days post hatch-dph, 0.77 mg wet weight) were given six feeding treatments intentionally designed to cause variations in the larvae growth rate: (A) only artemia nauplii; (CD) only a commercial diet; (ED) only a semi-purified experimental diet; (ACD) and (AED) two treatments that involved weaning; and (S) starvation. Early weaning from artemia nauplii to the formulated diets (ACD and AED) affected growth and survival of the pacu larvae compared with the exclusive use of artemia (A). Starvation (S) and the commercial diet (CD) caused total mortality in pacu larvae at 18 dph. The experimental diet (ED) assured low fish survival and growth. The skeletal muscle morphology was not affected by the delay in somatic growth from early weaning onto the formulated diets. Three distinct muscle compartments were observed throughout the larval development in treatments A, ACD and AED: superficial, deep and intermediate, accompanied by muscle thickening. Severe undernourishment caused drastic differences in growth and in the morphology of the muscle fibers. Pacu larvae fed only formulated diets (CD and ED) showed muscle characteristics similar to the larvae in starvation (S) during the first 15 dph. At 27 and 35 dph, a slight increase in epaxial muscle mass was noted in larvae fed only the experimental diet (ED). At 35 dph, we observed a high frequency of fibers >= 40 mu m in the larvae that were weaned onto the formulated diets (ACD and AED), indicative of hypertrophy. In contrast, the larvae fed only artemia nauplii (A) displayed a larger number of fibers with diameters <= 20 mu m, which is indicative of hyperplasia. The expression of the MyoD and myogenin genes in pacu larvae at 35 dph was not affected by initial feeding (p>0.05). In conclusion, the formulated diets used impaired pacu larvae growth and survival; therefore, they were inadequate for pacu, at least at the times they were introduced. Artemia nauplii were the most adequate food source during first feeding of the pacu, and they produced bigger fish upon completion of the experiment. Moreover, the contribution of hyperplasia to the skeletal muscle growth appeared higher in fast- than in slow-growing pacu larvae. (C) 2011 Elsevier By. All rights reserved.

Metallomic study on plasma samples from Nile tilapia using SR-XRF and GFAAS after separation by 2D PAGE: initial results

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

Structural characterization of 0.5PbMg(1/3)Nb(2/3)O(3)-0.5Ba(x)Pb((1-x))TiO(3) powders

The present work reports the effects caused by barium on phase formation, morphology and sintering of lead magnesium niobate-lead titanate (PMN-50PT). Ab initio study of 0.5PbMg(1/3)Nb(2/3)O(3)-0.5Ba(x)Pb((1-x))TiO(3) ceramic powders, with x = 0, 0.20, and 0.40 was proposed, considering that the partial substitution of lead by barium can reestablish the equilibrium of monoclinic-tetragonal phases in the system. It was verified that even for 40 mol% of barium, it was possible to obtain pyrochlore-free PMN-PT powders. The increase of the lattice parameters of PMN-PT doped-powders confirmed dopant incorporation into the perovskite phase. The presence of barium improved the reactivity of the powders, with an average particle size of 120 nm for 40 mol% of barium against 167 mn for the pure sample. Although high barium content (40 mol%) was deleterious for a dense ceramic, contents up to 20 mol% allowed 95% density when sintered at 1100 degrees C for 4 h. (c) 2007 Elsevier Ltd. All rights reserved.

Purification and characterization of the exopolygalacturonase produced by Aspergillus giganteus in submerged cultures

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

Carbon dioxide formation during initial stages of photodegradation of poly(ethyleneterephthalate) (PET) films

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

Nodule ultrastructure and initial growth of Anadenanthera peregrina (L.) Speg. var. falcata (Benth.) Altschul plants infected with rhizobia

The anatomy and ultrastructure of root nodules of Anadenanthera peregrina var. falcata (Leguminosae-Mimosoideae) were analysed, as was plant growth. To ensure that nodules developed, seedlings were inoculated with a mixture of six strains of rhizobia. Nodules were produced that differed in appearance-and probably also effectiveness-but their structure was similar and they showed characteristics typical of indeterminate nodules, such as persistent meristematic tissue and a gradient of cells at different stages of development. Many starch grains were present in inner cortex cells and interstitial cells of infected tissue. Infected cells were densely packed with bacteroids, which contained many poly-beta-hydroxybutyrate granules. The high incidence of these granules, together with high levels of starch accumulation in interstitial cells, suggested low N-2-fixation efficiency of the rhizobia isolates used for inoculation. In the symbiosomes of early-senescent infected cells, reticulum-like structures, small vesicles and a fibrillar material were observed; these may be related to bacteroid degradation. In the cytoplasm of late-senescent infected cells, many vesicles and membrane-like structures were observed, probably associated with membrane degradation of bacteroids and peribacteroids. The total biomass of plants inoculated with rhizobia was low and their xylopodia and shoots had low levels of N compared with non-inoculated plants fertilized with ammonium nitrate. However, inoculated plants did not show N-deficiency symptoms and grew better than non-inoculated plants without N fertilization. These growth results, together with ultrastructural observations of nodules, suggest that nitrogen fixation of rhizobia isolates associated with Anadenanthera peregrina var. falcata roots is poor. (C) 2002 Annals of Botany Company.

Bioconcentration of Cd and Pb by the River Crab Trichodactylus fluviatilis (Crustacea: Decapoda)

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

Initial structural analysis of an alpha(4)beta(4) C-type lectin from the venom of Crotalus durissus terrificus

Convulxin, an alphabeta C-type lectin, is a potent platelet activator isolated from the venom of the South American rattlesnake Crotalus durissus terrificus. It is a 26.5 kDa alphabeta heterodimer consisting of two homologous disulfide-linked chains. The crystals belong to space group I4, with unit-cell parameters a = b = 131.61, c = 121.85 Angstrom, and diffraction data were collected to 2.7 Angstrom. The structure was solved by molecular replacement and the asymmetric unit contains two alphabeta heterodimers, each of which forms a disulfide-linked cyclic alpha(4)beta(4) tetramer in the unit cell. These alpha(4)beta(4) tetramers are stacked to form a large solvent channel.

Dijet Azimuthal Decorrelations in pp Collisions at root s=7 TeV

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Indications of Suppression of Excited Upsilon States in Pb-Pb Collisions at root(NN)-N-s=2.76 TeV

A comparison of the relative yields of Upsilon resonances in the mu(+)mu(-) decay channel in Pb-Pb and pp collisions at a center-of-mass energy per nucleon pair of 2.76 TeV is performed with data collected with the CMS detector at the LHC. Using muons of transverse momentum above 4 GeV/c and pseudorapidity below 2.4, the double ratio of the Upsilon(2S) and Upsilon(3S) excited states to the Upsilon(1S) ground state in Pb-Pb and pp collisions, [Upsilon(2S + 3S)/Upsilon(1S)](Pb-Pb) /[Upsilon 2S + 3S)/Upsilon(1S)](pp), is found to be 0.31(-0.15)(+0.19) (stat_ +/- 0.03(syst). The probability to obtain the measured value, or lower, if the true double ratio is unity, is calculated to be less than 1%.

Measurement of the Pseudorapidity and Centrality Dependence of the Transverse Energy Density in Pb-Pb Collisions at root s(NN)=2.76 TeV

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Dissolved Po-210 and Pb-210 in Guarani aquifer groundwater, Brazil

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