Avaliação de populações de possíveis rizobactérias em solos sob espécies florestais

Embora estudos recentes relatem a utilização de RCPC (Rizobactérias Promotoras de Crescimento de Plantas) no Brasil, raríssimos trabalhos avaliam a presença natural dessas espécies bacterianas no solo. O objetivo deste trabalho foi avaliar a ocorrência de RPCP em duas amostras de solo sob diferentes tipos de manejo, através da construção e do seqüenciamento de bibliotecas de DNA metagenômico. Utilizaram-se oligonucleotídeos específicos para amplificação da região hipervariável do espaço intergênico dos genes ribossomais 16S-23S de DNA extraído de diferentes solos, sob Eucalyptus sp. e sob mata. Os fragmentos obtidos foram inseridos em vetor e clonados. As bibliotecas geraram 495 clones, que foram seqüenciados e identificados através de comparações realizadas pelo software Blast. O solo sob Eucalyptus sp. apresentou maior número de RPCP do que sob mata. Os filos Actinobacteria e Proteobacteria eram maiores no solo sob Eucalyptus sp., estando o filo Firmicutes ausente no solo sob mata. Somente oito espécies diferentes de RPCP foram detectadas: Bacillus subtilis, Bacillus megaterium, Bradyrhizobium japonicum, Bradyrhizobium elkanii, Bradyrhizobium sp., Frankia sp., Pseudomonas fluorescens e Pseudomonas gladioli. O trabalho forneceu valiosos dados sobre a presença de RPCP em solos com espécies florestais e sua possível utilização em reflorestamentos, assim como para o melhor conhecimento desses microrganismos nos solos do Brasil.

Espermidina exógena atenua os efeitos do NaCl na germinação e crescimento inicial de leguminosas forrageiras

Objetivou-se nesse estudo avaliar o papel atenuador da espermidina exógena sobre a germinação, vigor de sementes e crescimento de plântulas de cultivares das forrageiras alfafa, guandu e labe-labe submetidas ao estresse salino. A semeadura foi realizada em caixas de plástico tipo gerbox forradas com papel de filtro umedecidos com soluções salinas nas concentrações de 0, 20, 40, 60, 80 e 120 mM de NaCl contendo 0 ou 0,5 mM de espermidina. O delineamento experimental foi inteiramente casualizado em esquema fatorial 3 x 6 x 2 (forrageiras x salinidade x espermidina) com cinco repetições de 25 sementes. As avaliações da germinação foram realizadas no quarto e décimo dias, juntamente com o índice de velocidade de germinação (IVG), avaliado até o nono dia após a semeadura. Determinou-se a concentração salina que reduz em 50% a germinação e a massa seca da parte aérea e raiz no décimo dia após a semeadura. A aplicação de espermidina exógena proporcionou maior acúmulo de massa seca das raízes de labe-labe cv. Rongai, além de ter possibilitado a germinação de 50% das sementes de guandu cv. Caqui até a concentração salina de 72,09 mM de NaCl, assim como maior IVG nas sementes das leguminosas alfafa cv. Crioula e labe-labe cv. Rongai.

Emprego do cell block de agarose como método complementar no diagnóstico citológico de tumores mamários caninos

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

THE EFFECT OF TUBEROINFUNDIBULAR DOPAMINERGIC-NEURONS ON PROLACTIN AND ALPHA-MELANOCYTE STIMULATING HORMONE-RELEASE

The effect of tubero-infundibular dopaminergic neurons (TIDA) on the release of prolactin (PRL) and alpha-melanocyte stimulating hormone (alpha-MSH) was studied in median eminence-lesioned (MEL) male rats (N = 6-28). Plasma PRL and alpha-MSH levels were significantly elevated 2 (86.1 +/- 19.8 and 505.1 +/- 19.1 ng/ml), 4 (278.7 +/- 15.5 and 487.4 +/- 125.1 ng/ml), 7 (116.2 +/- 16.2 and 495.8 +/- 62.6 ng/ml) and 14 (247.3 +/- 26.1 and 448.4 +/- 63.8 ng/ml) days after MEL when compared to sham-operated control animals (55.5 +/- 13.4 and 56.2 +/- 6.1 ng/ml, respectively). MEL altered plasma PRL and alpha-MSH levels in a differential manner, with a 1.5-to 5.0-fold increase in PRL and an 8.0-to 9.0-fold increase in alpha-MSH. The increase of alpha-MSH levels occurred abruptly and remained constant from days 2 to 14. These observations indicate that TIDA plays an important role in the pituitary release of PRL and alpha-MSH and provide evidence that the release of the two hormones occurs in a differential manner.

Developmental lead exposure: behavioral alterations in the short and long term

Wistar dams were exposed to 500 ppm of Pb, as Ph acetate, or 660 ppm Na acetate in drinking water during pregnancy and lactation. Male pups at 23 (weaned) or 70 days (adult) of age were submitted to behavioral evaluation and Pb determination. The behaviors evaluated were: locomotor activity (open-field test), motor coordination (rotarod test), exploratory behavior (holeboard test), anxiety (elevated plus maze and social interaction tests), and learning and memory (shuttle box). Ph levels were measured in the blood and cerebral regions (hippocampus and striatum) of dams and pups. The results of the present report demonstrated that exposure to Ph during pregnancy and lactation induces in weaned pups hyperactivity, decreased exploratory behavior, and impairment of learning and memory. These alterations were observed at blood Ph levels in the range that may be attained in children chronically exposed to low levels of Pb (21 +/- 3 mug/dl). Regarding adults, the results demonstrated that the regimen of exposure adopted induces anxiety in these animals at nondetectable blood Ph levels. (C) 2001 Elsevier B.V. All rights reserved.

Surface conditioning of a composite used for inlay/onlay restorations: Effect on mu TBS to resin cement

Purpose: To assess the effect of the composite surface conditioning on the microtensile bond strength of a resin cement to a composite used for inlay/onlay restorations.Materials and Methods: Forty-two blocks (6 x 6 x 4 mm) of a microfilled composite (Vita VMLC) were produced and divided into 3 groups (N = 14) by composite surface conditioning methods: Gr1 - etching with 37% phosphoric acid, washing, drying, silanization; Gr2 - air abrasion with 50-Im Al203 particles, silanization; Gr3 - chairside tribochemiCal silica coating (CoJet System), silanization. Single-Bond (one-step adhesive) was applied on the conditioned surfaces and the two resin blocks treated with the same method were cemented using RelyX ARC (dual-curing resin cement). The specimens were stored for 7 days in water at 37 degrees C and then sectioned to produce nontrimmed beam samples, which were submitted to microtensile bond strength testing (mu TBS). For statistical analysis (one-way ANOVA and Tukey's test, = 0.05), the means of the beam samples from each luted specimen were calculated (n = 7).Results: mu TBS values (MPa) of Gr2 (62.0 +/- 3.9a) and Gr3 (60.5 +/- 7.9a) were statistically similar to each other and higher than Gr1 (38.2 +/- 8.9b). The analysis of the fractured surfaces revealed that all failures occurred at the adhesive zone.Conclusion: Conditioning methods with 50-Im Al203 or tribochemical silica coating allowed bonding between resin and composite that was statistically similar and stronger than conditioning with acid etching.

Tabu search algorithm for network synthesis

Large scale combinatorial problems such as the network expansion problem present an amazingly high number of alternative configurations with practically the same investment, but with substantially different structures (configurations obtained with different sets of circuit/transformer additions). The proposed parallel tabu search algorithm has shown to be effective in exploring this type of optimization landscape. The algorithm is a third generation tabu search procedure with several advanced features. This is the most comprehensive combinatorial optimization technique available for treating difficult problems such as the transmission expansion planning. The method includes features of a variety of other approaches such as heuristic search, simulated annealing and genetic algorithms. In all test cases studied there are new generation, load sites which can be connected to an existing main network: such connections may require more than one line, transformer addition, which makes the problem harder in the sense that more combinations have to be considered.

Chemical evolution in the Asteraceae. The Oxidation-Reduction mechanism and production of secondary metabolites

This work describes the application of partial least squares (PLS) regression to variables that represent the oxidation data of several types of secondary metabolite isolated from the family Asteraceae. The oxidation states were calculated for each carbon atom of the involved compounds after these had been matched with their biogenetic precursor. The states of oxidation variations were named oxidation steps. This methodology represents a new approach to inspect the oxidative changes in taxa. Partial least square (PLS) regression was used to inspect the relationships among terpenoids, cournarins, polyacetylenes, and flavonoids from a data base containing approximately 27,000 botanical entries. The results show an interdependence between the average oxidation states of each class of secondary metabolite at tribe and sub tribe levels.

Purification, crystallization and preliminary X-ray analysis of haemoglobin I from the armoured catfish Liposarcus anisitsi

Liposarcus anisitsi is an armoured catfish that presents accessorial air oxygenation through a modified stomach, which allows this species to survive in waters with very low oxygen content. Analysis of its haemolysate has shown the presence of four haemoglobins; this work focuses on the main component, haemoglobin I. It has been crystallized in two different forms and X-ray diffraction data have been collected to 2.77 and 2.86 Angstrom resolution using synchrotron radiation. Crystals were determined to belong to the space groups C2 and P2(1) and preliminary structural analysis revealed the presence of one tetramer in the asymmetric unit in both crystal forms. The structure was determined using a standard molecular-replacement technique.

SYNTHESIS AND CRYSTAL-STRUCTURE OF THE NOVEL CYCLOPALLADATED COMPLEX DI(MU,N-S-ETA(2)-QUINOLINE-2-THIOLATE)-BIS[(N,N-DIMETHYLBENZYLAMINE-C(2),N) PALLADIUM(II)]

The compound di(mu,N-Seta2-2-quinoline-2-thiolate)-bis[(N,N-dimethylbenzylamine-C2,N)palladium(II)] was synthesized and studied by IR, NMR and X-ray diffraction: monoclinic, a = 20.138(3), b = 10.831(1), c = 14.973(2) angstrom, beta = 98.04(1)-degrees, Z = 4, space group P2(1)/c, R = 0.032. The compound is dimeric with the two [Pd(N,N-dimethylbenzylamine)]moieties being connected by the two vicinal bridging eta2-N,S-quinoline-2-thiolate anions in a square-planar coordination geometry for the palladium atoms.

Synthesis, crystal structure, spectroscopic and electrochemical characterization of the dinuclear complex {tetra-mu-[(+/-)-2-(p-methoxyphenoxy)-propionato-O,O']bis(aqua)dicopper(II)}

Structural, electrochemical and spectroscopic data of a new dinuclear copper(II) complex with (+/-)-2-(p- methoxyphenoxy) propionic acid are reported. The complex {tetra-mu-[(+/-)-2-(p-methoxyphenoxy)propionato-O,O']-bis( aqua) dicopper(II)} crystallizes in the monoclinic system, space group P2(1)/n with a = 14.149(1) angstrom, b = 7.495(1) angstrom, c = 19.827(1) angstrom, beta = 90.62(1) and Z = 4. X-ray diffraction data show that the two copper(II) ions are held together through four carboxylate bridges, coordinated as equatorial ligands in square pyramidal geometry. The coordination sphere around each copper ion is completed by two water molecules as axial ligands. Thermogravimetric data are consistent with such results. The ligand has an L' type shape due to the angle formed by the beta-carbon of the propionic chain and the linked p-methoxyphenoxy group. This conformation contributes to the occurrence of a peculiar structure of the complex. The complex retains its dinuclear nature when dissolved in acetonitrile, but it decomposes into the corresponding mononuclear species if dissolved in ethanol, according to the EPR measurements. Further, cyclic voltammograms of the complex in acetonitrile show that the dinuclear species maintains the same structure, in agreement with the EPR data in this solvent. The voltammogram shows two irreversible reduction waves at E-pc = -0.73 and -1.04 V vs. Ag/AgCl assigned to the Cu(II)/ Cu(I) and Cu(I)/Cu degrees redox couples, respectively, and two successive oxidation waves at E-pa = -0.01 and +1.41 V vs. Ag/AgCl, assigned to the Cu degrees/Cu(I) and Cu( I)/Cu( II) redox couples, respectively, in addition to the oxidation waves of the carboxylate ligand.

Legitimacy and context: Implications for public sector reform in developing countries

This article examines the interplay between legitimacy and context as key determinants of public sector reform outcomes. Despite the importance of variables Such as legitimacy of public institutions, levels of civic morality and socio-economic realities, reform strategies often fail to take such contextual factors into account. The article examines, first, relevant literature both conceptual and empirical, including data from the World Values Survey project. It is argued that developing countries have distinctive characteristics which require particular reform strategies. The data analysed shows that in Latin American countries, there is no clear Correlation between confidence in public institutions and civic morality. Other empirical studies show that unemployment has a negative impact on the level of civic morality, while inequality engenders corruption. This suggests that poorer and socio-economically stratified countries face greater reform challenges owing to the lack of legitimacy of public institutions. The article concludes that reforms should focus on areas of governance that impact on poverty. This will in turn help produce more stable outcomes. Copyright (C) 2008 John Wiley & Sons, Ltd.

Influence of creatine supplementation on bone quality in the ovariectomized rat model: an FT-Raman spectroscopy study

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)