Vertical distribution of biotic pollination systems in cerrado sensu stricto in the Triangulo Mineiro, MG, Brazil)

(Vertical distribution of biotic pollination systems in cerrado sensu stricto in the Triangulo Mineiro, MG, Brazil). Several factors can influence the distribution of floral resources and pollination systems in ecosystems, such as climate, altitude, geographic region, fragmentation of natural areas and differences in floristic composition along the vertical stratification. This study aimed to evaluate the distribution of the vertical stratification of biotic pollination systems in cerrado (sensu stricto) fragments in the Triangulo Mineiro. There was no significant difference (chi(2)(0.05,9)=14.17; P = 0.12) in total plant species richness among fragments, nor in the species richness of each layer (trees, shrubs, herbs and lianas) and the shrub layer was the best represented. Likewise, there was no significant difference between fragments for the systems of pollination (chi(2)(0 05,21) =13.80; P = 0.8778). Pollination by bees was the most common, corresponding to 85% of species in each fragment. In relative terms, plants pollinated by bees were dominant in all strata, reaching 100% for the lianas in fragments 1, 3 and 4 and for the herbs in fragments 1 and 4. In this study, based on floristic composition and distribution of biotic pollination systems in the vertical stratification, we could define a vertical mosaic in the cerrado studied, which has implications for the sustainability of communities in the cerrado, as well as the horizontal mosaic of vegetation types.

Desempenho de cultivares de morango submetidas a diferentes tipos de polinização em cultivo protegido

Resumo – O objetivo deste trabalho foi avaliar o efeito de diferentes tipos de polinização sobre a qualidade de frutos de cultivares de morangueiro e sua contribuição isolada para a massa dos frutos, bem como determinar o potencial de Plebeia nigriceps (Hymenoptera: Apidae, Meliponini) como agente polinizador em ambiente protegido. As cultivares Aromas, Diamante e Cegnidarem foram submetidas a tratamentos com autopolinização, polinização por P. nigriceps e polinização livre. Os experimentos foram conduzidos em estufa tipo pampeana, coberta com polietileno transparente e desprovida de telas anti-insetos nas laterais, com 1.344 plantas. Para as avaliações, foram marcadas 56 flores primárias em botão, de cada cultivar, e considerou-se cada planta uma repetição. Avaliaram-se massa de matéria fresca, peso, diâmetro, comprimento e presença de deformação nos frutos. A polinização entomófila tem contribuição variada à massa dos frutos, de acordo com a cultivar. As cultivares apresentam sensibilidade variada à autopolinização, no que se refere à incidência de frutos deformados. Ainterferência da polinização entomófila na produtividade do morangueiro está mais relacionada à redução do percentual de frutos deformados do que ao aumento da massa dos frutos em si. O comportamento de P. nigriceps indica que a espécie apresenta potencial para polinização da cultura do morangueiro em ambiente protegido.

Determination of flagellar types by PCR-RFLP analysis of enteropathogenic Escherichia coli (EPEC) and Shiga toxin-producing E. coli (STEC) strains isolated from animals in Sao Paulo, Brazil

This study evaluated the polymerase chain reaction- restriction fragment length polymorphism (PCR-RFLP) analysis of fliC for typing flagella antigen (H) of Shiga toxin-producing Escherichia coil (STEC) and enteropathogenic E. coli (EPEC) strains isolated from different animals. The molecular typing of the H type was efficient in the determination of 93 (85%) strains. Two nonmotile (H-) E. coil strains showed a PCR-RFLP electrophoretic profile that did not match known H type patterns. The fliC nucleotide sequence of strains B2N and 4a revealed a nucleotide substitution at the restriction site and a nucleotide insertion that generated a stop codon, respectively. The results of this study showed that PCR-RFLP analysis of fliC is faster, less laborious and as efficient for the determination of H type E. coli isolated from animals, compared to serotyping and that it is useful in determining H type in nonmotile strains and strains expressing non-reactive H antigens. Moreover, the fliC sequence of strain B2N suggests that we could have found a new flagellin antigen type. (C) 2010 Elsevier Ltd. All rights reserved.