Variation in arbuscular mycorrhizal fungi (AMF) communities is described for the first time in rupestrian grasslands in Brazil along an altitudinal gradient of 700 m (800 to 1400 m a.s.l.). Hypotheses tested were that soil properties influence the variation in AMF communities and that the frequency of the most common species of AMF is inversely influenced by the richness of other AMF. Field and laboratory data were collected on AMF community composition, richness, density, and frequency in the altitudinal gradient, and the relationships with several physical-chemical soil properties and altitude were evaluated. Fifty-one species of AMF were recorded, with 14 species being reported as possibly new to science and nine species representing new records for Brazil. This single elevation gradient alone contains 22% of the known world diversity of AMF. Soil properties and AMF community density and richness varied significantly along the elevation (p < 0.05). AMF density and richness were higher at the intermediate altitude, while AMF species composition differed statistically among the altitudes.

Genetic diversity among 37 isolates of the sorghum anthracnose pathogen Colletotrichum graminicola, from four geographically distinct regions of Brazil, was evaluated by RAPD and RFLP-PCR markers and virulence characters on a set of 10 differential sorghum genotypes. Twenty-two races were identified and race 13B was the most frequent, but present in only two regions. RAPD analysis revealed 143 polymorphic bands that grouped the isolates according to their geographic origin, but not by their virulence phenotypes. RFLP with HaeIII, MspI, HinfI, HhaI, HpaII, EcoRI, HindIII, PstI, RsaI, Taq alphaI, and AluI enzymes over ITS domains and 5.8 rDNA genes of C. graminicola did not show differences among the isolates, indicating high conservation of these restriction sites. Molecular polymorphism was observed among isolates belonging to the same race. No association between virulence phenotypes and molecular profiles was observed.

Thirteen strains of the genus Candida were isolated from catheter, urine and surgical wounds from individual patients of the Santa Casa de Misericórdia, Belo Horizonte, MG, Brazil. Ten strains were characterized as Candida albicans, two as Candida glabrata, and one as Candida parapsilosis. Isolates were evaluated for molecular relatedness by random amplified polymorphic DNA technique using 15 primers. The analysis of the genomic DNA obtained revealed a low intraspecific polymorphism and did not allow for the differentiation between strains of the same species obtained from distinct clinical sources (catheter, urine and surgical wounds). The RAPD profiles generated were able to differentiate among the species of Candida albicans, Candida parapsilosis and Candida glabrata strains isolated in this study. Key-words: Candida spp. Random amplified polymorphic DNA. Polymorphism. Nosocomial infection. RESUMO Treze amostras de leveduras do gênero Candida foram isoladas de catéter, urina e feridas cirúrgicas de pacientes da Santa Casa de Misericórida de Belo Horizonte, MG, Brasil. Dez amostras foram identificadas como Candida albicans, duas comoCandida glabrata e uma como Candida parapsilosis. Os isolados foram avaliados quanto ao perfil molecular pela técnica de amplificação aleatória de DNA polimórfico utilizando 15 iniciadores. A análise do DNA genômico obtido revelou um baixo polimorfismo intraespecífico e não permitiu a diferenciação entre amostras da mesma espécie obtidas a partir de diferentes espécimes clínicos (catéter, urina e feridas cirúrgicas). Os perfis de RAPD obtidos foram capazes de diferenciar entre as espécies Candida albicans, Candida parapsilosis e Candida glabrata isoladas neste estudo. Palavras-chaves: Candida spp. Amplificação aleatória de DNA polimórfico. Polimorfismo. Infecção nosocomial.

Entomopathogenic fungi are important controllers of pest-insects populations in agricultural production systems and in natural environment. These fungi have enzymatic machinery which involve since the recognition and adherence of spores in their hosts culminating with infection and death of these insects. The main objective of this study was to analyzed extracellular enzyme production of the fungi strains Beauveria bassiana, Metarhizium anisopliae and Paecilomyces sp when cultured on substrates. These fungi were grown in minimal media containing specific substrates for the analysis of different enzymes such as amylases, cellulases, esterases, lipases, proteases (gelatin and caseinase), pectinases and cuticles of Musca domestica larvae and adults. All the assays were performed with and without the presence of dextrose in the culture media. The quantification of enzyme activity was performed by the ratio of halo / colony (H/C) and the results subjected to variance analysis level of 5% (ANOVA) followed by post-Tukey test. All strains were positive for lipase and also they showed a high significant enzyme production for gelatin at concentrations of 4 and 1%. B. bassiana and Paecilomyces sp. were positive for amylase, pectinase and caseinase, and only Paecilomyces sp. showed cellulase activity.

The aim of this study was to quantify and evaluate the antibacterial activity of tannins extracted from leaves of Psidium guineense, obtained using two different isolation methods, against Staphylococcus aureus and Pseudomonas aeruginosa. The first extraction method was used to isolate condensed tannins (Method A) and the second to isolate mixtures rich in esters of gallic acid and glucose (Method B). Both extraction methods yielded high concentrations of tannins, with 312 and 257 mg/g of dry material obtained using Methods A and B, respectively. These compounds formed halos of growth inhibition in S. aureus and P. aeruginosa cultures. Tannins isolated by method B gave rise to larger inhibition halos than those isolated by method A. Analysis of the antibacterial activity of tannins isolated by method B revealed a minimum inhibitory and bactericidal concentration of 256 μg/ml for S. aureus and 512 μg/ml for P. aeruginosa. These results demonstrate that P. guineense is a promising source of pharmacologically active tannin molecules, and further studies are therefore necessary to determine the toxicity of the plant and ensure its safe use for animal and human health.