RESUMO
Co-2 is one of the R-genes against anthracnose identified in common bean. A RAPD marker, cloned as PvH20, was previously shown to contain 6 imperfect leucine-rich-repeats and to reveal a family of related sequences in the vicinity of the Co-2 locus. Using PvH20 as probe, a genomic clone and 2 partial cDNAs were isolated. DNA sequencing revealed that the 6.1 kb genomic fragment contains sequences encoding both NBS-LRR (ORF1) and kinase-like (ORF2) products. The 2 partial cDNAs (cD7 and cD8) belong to the NBS-LRR subfamily as do most of the resistance genes cloned to date. The LRR domain of ORF1 is interrupted by 2 stop codons suggesting that it corresponds to a non-functional member of the multigene family and ORF2 appears to be a kinase pseudogene. The 3 NBS-LRR polypeptides share a high level of amino acid identity and represent different members of a related family. By genetic mapping ORF1, cD7, and cD8 were found to span a genetic distance of 3 cM: cD8 maps at 2 cM from Co-2 and 3 cM from ORF1, cD7 maps at 1 cM from ORF1 and co-segregates with Co-2, thus cD7 might be a putative candidate for the Co-2 R-gene.
Assuntos
Fabaceae/genética , Plantas Medicinais , Proteínas/genética , Sequência de Aminoácidos , Sequência de Bases , Mapeamento Cromossômico , Clonagem Molecular , DNA de Plantas , Genes de Plantas , Proteínas de Repetições Ricas em Leucina , Dados de Sequência Molecular , Família Multigênica , Fases de Leitura AbertaRESUMO
Four atypical coagulase-negative staphylococcal (CNS) isolates from clinical sources were compared with Staphylococcus epidermidis strains by ribotyping. The ribotypes of the four strains shared close rDNA restriction profiles with those of the S. epidermidis strains used. The DNA sequence encoding 16S rRNA demonstrated 99.9% homology with S. epidermidis. S1 nuclease experiments showed that these atypical strains formed a homogeneous genomic group. DNA-DNA homologies between the S. epidermidis type strain CCM 2124 and the four CNS isolates ranged from 70 to 89%. The guanine-plus-cytosine content of the deoxyribonucleic acid of the four strains ranged from 31 to 32 mol%.
Assuntos
Formas Bacterianas Atípicas/classificação , Técnicas de Tipagem Bacteriana , Técnicas de Sonda Molecular , Staphylococcus epidermidis/classificação , Aminoácidos/análise , Formas Bacterianas Atípicas/química , Formas Bacterianas Atípicas/isolamento & purificação , Parede Celular/química , DNA Ribossômico/análise , Genótipo , Humanos , Peptidoglicano/química , Fenótipo , Fósforo/análise , RNA Ribossômico 16S/classificação , RNA Ribossômico 16S/genética , Staphylococcus epidermidis/química , Staphylococcus epidermidis/isolamento & purificaçãoRESUMO
A 1.64-kb cDNA encoding an Arabidopsis thaliana mevalonate kinase (MK) was cloned by complementation of the erg 12-1 mutation affecting MK in the yeast Saccharomyces cerevisiae, and the nucleotide sequence was determined. The longest open reading frame encodes a protein of 378 amino acids (aa) with a predicted molecular mass of 40,650 Da. A striking feature of the cDNA sequence is a long 5' untranslated region (322 bp). The deduced aa sequence reveals that the plant enzyme shows strong similarities to the yeast and mammalian enzymes, especially the strong hydrophobicity percentage and several conserved regions. Southern analysis suggests that probably only one locus exists in the A. thaliana genome.