Bean tissue culture for introduction of foreign genes

O objetivo deste trabalho foi determinar parâmetros da cultura de tecidos de feijoeiro necessários para a aplicação da técnica de transformação via Agrobacterium. Diversos genótipos de feijoeiro (Phaseolus vulgaris L.) foram cultivados in vitro. Alguns parâmetros visando à infecção de ápices caulinares com Agrobacterium tumefaciens foram otimizados, como a eliminação da agrobactéria após a co-cultura e a concentração de kanamicina suficiente para a seleção dos ápices infectados. Multibrotações em nós cotiledonares foram obtidas com freqüência de até 55,7%, dependendo do genótipo utilizado. Estes nós foram infectados com A. tumefaciens contendo em seu plasmídeo Ti o gene da β-glucuronidase (GUS) sob regulação de promotor eucariótico. Entre as multibrotações obtidas, 30% apresentaram região onde foi detectada atividade do gene GUS. Demonstrou-se também a susceptibilidade de feijoeiro a Agrobacterium rhizogenes. Raízes transgênicas foram obtidas após infecção de epicótilos.The objective of this work was to determine different bean tissue culture parameters necessary to the application of Agrobacterium-mediated transformation technique. Several bean (Phaseolus vulgaris L.) genotypes were cultured in vitro. The protocols for Agrobacterium elimination, after infection of the apical meristems with Agrobacterium tumefaciens and the selective kanamycin concentration were determined. Depending on the genotype, multiple buds were obtained from cotiledonary nodes in a frequency up to 55.7%. The cotiledonary nodes were infected with A. tumefaciens carrying in the Ti plasmid the gene for β-glucuronidase (GUS) under the control of an eucariotic promoter. Regions with GUS activity were detected in 30% of the shoots. The susceptibility of bean to Agrobacterium rhizogenes was also shown. Transgenic roots were obtained after infection of epicotyls with A. rhizogenes

Characterisation of microbial attack on archaeological bone

As part of an EU funded project to investigate the factors influencing bone preservation in the archaeological record, more than 250 bones from 41 archaeological sites in five countries spanning four climatic regions were studied for diagenetic alteration. Sites were selected to cover a range of environmental conditions and archaeological contexts. Microscopic and physical (mercury intrusion porosimetry) analyses of these bones revealed that the majority (68%) had suffered microbial attack. Furthermore, significant differences were found between animal and human bone in both the state of preservation and the type of microbial attack present. These differences in preservation might result from differences in early taphonomy of the bones. © 2003 Elsevier Science Ltd. All rights reserved