RESUMO
An introgression derived from the B genome of Brassica juncea in spring-type oilseed rape (B. napus) conferring recessively inherited cotyledon resistance against several pathotypes of the blackleg fungus Leptosphaeria maculans was mapped using PCR-based molecular markers. Resistance-associated B-genome-specific randomly amplified (RAPD) and resistance gene analog (RGA) DNA polymorphisms were converted into three sequence-specific markers (SCARs; B5-1520, C5-1000, RGALm). The flanking sequence of the RGALm locus was determined by genomic walking, leading to a 1,610-bp EcoRV fragment which showed extensive homology to known and putative resistance genes of a cluster on Arabidopsis chromosome 5. Partial sequence analysis of the genomic RAPD segment OPC-05-1700 revealed strong homology to the gibberellin 2-oxidase gene of Arabidopsis. The SCAR markers were analyzed in two segregating populations and were found to be linked in coupling to each other, and in repulsion to the resistance locus. In both populations, markers deviated significantly from a monogenic 3:1 segregation ratio, with plants lacking the markers being more frequent than expected. Although the mode of introgression is yet unknown, the recombinant individuals observed among susceptible progeny suggest homeology between the B-genome-specific segment and its B. napus counterpart. This would offer prospects for reducing the size of the introgression and further fine mapping of the resistance locus.
Assuntos
Ascomicetos , Brassica napus/genética , Marcadores Genéticos/genética , Imunidade Inata/genética , Doenças das Plantas/microbiologia , Sequência de Bases , Clonagem Molecular , Cruzamentos Genéticos , Primers do DNA , Genética Populacional , Oxigenases de Função Mista/genética , Dados de Sequência Molecular , Doenças das Plantas/genética , Técnica de Amplificação ao Acaso de DNA Polimórfico , Análise de Sequência de DNA , Homologia de Sequência , Especificidade da EspécieRESUMO
The three B genomes of Brassica contained in B. nigra, B. carinata and B. juncea were dissected by addition in B. napus. Using phenotypic, isozyme and molecular markers we characterized 8 alien B-genome chromosomes from B. nigra and B. carinata and 7 from B. juncea by constructing synteney groups. The alien chromosomes of the three different sources showed extensive intragenomic recombinations that were detected by the presence of the same loci in more than one synteny group but flanked by different markers. In addition, intergenomic recombinations were observed. These were evident in euploid AACC plants of the rapeseed phenotype derived from the addition lines carrying a few markers from the B genome due to translocations and recombinations between non-homoeologous chromosomes. The high plasticity of the Brassica genomes may have been an powerful factor in directing their evolution by hybridization and amphiploidy.
RESUMO
Heparin cofactor II (HC II) is known as a bifunctional inhibitor inactivating trypsin- and chymotrypsin type proteases. Its inhibitory activity increases in the presence of heparin, dermatan sulfate and chondroitin E. In the present study the inhibitory activity of HC II was investigated as function of various dermatan sulfate fractions and its stability was tested against oxidation reagents similar to thus secreted by activated leucocytes. High affinity dermatan sulfate (DS) increased the antithrombin inhibition activity of HC II about 1000-fold in contrast to about 100-fold in the case of low affinity DS. Oxidation of HC II carbohydrate side chains with sodium periodate showed less inactivation effects than oxidation by chloramine T or ammonium peroxodisulfate.
