Produção de biomassa e estrutura do pasto de capim-andropogon em sistema silvipastoril e monocultura / Biomass production and pasture structure of Andropogon grass in a silvopastoral system and in monoculture

A produção de biomassa e as características estruturais do capim-andropogon foram avaliadas nas idades de rebrota de 35, 49 e 63 dias, em três ambientes de um sistema silvipastoril: sob a copa de pau-d'arco, sob a copa de jatobá, em área aberta; local fora da copa de qualquer árvore e em sistema de monocultura. O delineamento experimental foi o de parcelas subdivididas com cinco repetições. As parcelas foram representadas pelos ambientes e as subparcelas, pelas idades de rebrota. A luminosidade sob pau-d'arco, sob jatobá e em área aberta foi de 74, 62 por cento e 82 por cento, respectivamente, das áreas a pleno sol. Houve interação ambiente versus idade de rebrota. O sombreamento sob a copa de pau-d'arco e de jatobá não afetou a produção de matéria seca do capim-andropogon, contudo reduziu a altura do pasto aos 63 dias de rebrota. O percentual de folhas da forragem aos 35 dias de rebrota foi mais elevado na monocultura. Nas outras idades de rebrota, os quatro ambientes não diferiram entre si.

The biomass production and pasture structure of Andropogon grass were evaluated at 35, 49, and 63 days of regrowth, in three silvopastoral environments: under Pau-d'Arco and Jatobá trees, in open field and in monoculture system. The experiment was designed in split plot with five replications, the plots were the environments and the split plots were the regrowth ages. The luminosities under Pau-d'Arco, Jatobá, and open field were: 74, 62, and 82 percent, respectively, relative to the areas under full sun. There was interaction among environments and ages of regrowth. The shading under the canopy of Pau-d'Arco and Jatobá did not affect the production of dry matter of Andropogon grass; however, reduced the height of the grass at 63 days of regrowth. The percentage of leaves of forage at 35 days of regrowth was higher in monoculture. At other ages of regrowth, the four environments did not differ among themselves.

Atividade hemolítica e produção de tubos germinativos relacionados ao potencial patogênico de isolados clínicos de Candida albicans / Hemolytic activity and production of germ tubes related to pathogenic potential of clinical isolates of Candida albicans

We assessed the virulence factor profile and in vitro antifungal susceptibility of 27 hospital isolates of C. albicans; 19 of these were from infections (16 urinary and three blood), and the other eight were isolated from sites of colonization (two from hands of health professionals, and six from central venous catheters). The virulence factors assayed were germ tube formation and production of extracellular products (hemolysins, proteinases, and phospholipases). Susceptibility to fluconazole, itraconazole, voriconazole and amphotericin B was determined by E-test. Regarding the virulence factors, the infection isolates produced significantly more hemolysin and germ tubes than the colonization isolates (p<0.05). There were no significant differences in the production of other factors between isolates from the two sources (p>0.05). Amphotericin B showed the lowest minimum inhibitory concentrations for all the isolates. The highest resistance was observed for the azoles, especially in the clinical isolates. These results suggest that the capacity of C. albicans to produce hemolysins and germ tubes may be associated with its pathogenic potential. Colonization isolates may pose a high risk of nosocomial infection, especially when the yeasts show resistance to antifungals.

O perfil de virulência e o de susceptibilidade in vitro aos antifúngicos de 27 amostras de C. albicans de origem hospitalar foi avaliado, sendo que 19 delas foram isoladas de infecções (16 urinárias e três sanguíneas) e as outras oito foram isoladas de colonização (duas de mãos de profissionais da saúde e seis de cateter venoso central). Os seguintes fatores de virulência foram investigados: formação de tubo germinativo e produção de compostos extracelulares (hemolisinas, proteinases e fosfolipases). Suscetibilidade ao fluconazol, itraconazol, voriconazol e anfotericina B foram determinadas por E-test. Em relação aos fatores de virulência, os isolados de infecção produziram significativamente mais hemolisina e tubos germinativos do que os de colonização (p<0.05). Não houve diferença significativa na produção das outras enzimas, entre os isolados das duas fontes (p>0.05). Anfotericina B mostrou as menores concentrações inibitórias mínimas para todos os isolados. Maiores índices de resistência foram observados aos azólicos, especialmente entre os isolados clínicos. Estes resultados sugerem que a capacidade de C. albicans produzir hemolisinas e tubos germinativos pode estar associada com seu potencial patogênico. Por outro lado, leveduras em colonização podem oferecer alto risco para infecção hospitalar, especialmente quando têm perfil de resistência aos antifúngicos.

Degradabilidade ruminal in situ de vagens de faveira (Parkia platycephala Benth.) em diferentes tamanhos de partículas / In situ ruminal degradability of faveira (Parkia platycephala Benth.) pods in different particle sizes

Estimaram-se os parâmetros de degradação ruminal da matéria seca (MS) e da proteína bruta (PB) de vagens de faveira, trituradas em partículas de 2 e 5mm, pelo método do saco de náilon in situ em ovinos, nos tempos de incubação 3, 6, 12, 24, 48, 72 e 96 horas, e determinou-se a degradabilidade efetiva, considerando-se taxas de passagem 2, 5 e 8 por cento/h. A fração a da MS e da PB foram 69,6 e 49,9 por cento, respectivamente, revelando elevada solubilidade da MS; a fração b para MS e PB foi 24,7 e 43,9 por cento, indicando baixa degradação da MS in situ, com estabilização da degradação da MS às 72h e da PB às 48h de incubação. O tanino de vagens de faveira não se mostrou depressor da degradabilidade in situ da PB

Soluble (a) and potentially degradable (b) fractions and degradation rate of b fraction (c) of dry matter (DM) and crude protein (CP) of Parkia platycephala pods in particle sizes 2 and 5mm were estimated by in situ nylon bag method in sheep. The times of incubation were 3, 6, 12, 24, 48, 72 and 96 hours, and the effective degradability (ED) was determined considering passage rates of 2, 5 and 8 percent/h. The a fractions for DM and CP was 69.6 and 49.9 percent, respectively, revealing elevated DM solubility: The b fractions for DM and CP was 24.7 and 43.9 percent, denoting reduced DM in situ degradation. The stabilization of the DM and CP degradation occurred at 72h and 48h after incubation, respectively. In situ degradability of constituents of P. platycephala pods, in special CP, were not depressed for their tannin contents

Evaluation by blue native polyacrylamide electrophoresis colorimetric staining of the effects of physical exercise on the activities of mitochondrial complexes in rat muscle

Blue native polyacrylamide electrophoresis (BN-PAGE) is a technique developed for the analysis of membrane complexes. Combined with histochemical staining, it permits the analysis and quantification of the activities of mitochondrial oxidative phosphorylation enzymes using whole muscle homogenates, without the need to isolate muscle mitochondria. Mitochondrial complex activities were measured by emerging gels in a solution containing all specific substrates for NADH dehydrogenase and cytochrome c oxidase enzymes (complexes I and IV, respectively) and the colored bands obtained were measured by optique densitometry. The objective of the present study was the application of BN-PAGE colorimetric staining for enzymatic characterization of mitochondrial complexes I and IV in rat muscles with different morphological and biochemical properties. We also investigated these activities at different times after acute exercise of rat soleus muscle. Although having fewer mitochondria than oxidative muscles, white gastrocnemius muscle presented a significantly higher activity (26.7 ± 9.5) in terms of complex I/V ratio compared to the red gastrocnemius (3.8 ± 0.65, P < 0.05) and soleus (9.8 ± 0.9, P < 0.001) muscles. Furthermore, the complex IV/V ratio of white gastrocnemius muscle was always significantly higher when compared to the other muscles. Ninety-five minutes of exhaustive physical exercise induced a decrease in complex I/V and complex IV/V ratios after all resting times (0, 3 and 6 h) compared to control (P < 0.05), probably reflecting the oxidative damage due to increasing free radical production in mitochondria. These results demonstrate the possible and useful application of BN-PAGE-histochemical staining to physical exercise studies.