RESUMO
This communication describes the cloning of a 1.8-kb fragment from the genome of the corynephage phi AAU2, which aborts the phage lytic cycle when cloned on a high-copy shuttle vector. The associated phenotype, called Apld (aborting phage lytic development), was revealed by noting the reduced plaque size and lower efficiencies of plaquing of phi AAU2 cp, a virulent derivative of phi AAU2, on "Arthrobacter aureus"-C70 Apld+ cells. Adsorption and phage DNA transfection experiments showed evidence that Apld acted once the phage DNA had entered into the cell; apld was confined to a single open reading frame (ORF), encoding a putative 63-aa polypeptide which did not show any homology to proteins contained in the databanks; apld is followed by an ORF the product of which shows homology with a protein expressed by the early region of the Streptomyces phage phi C31.
Assuntos
Arthrobacter/genética , Bacteriófagos/química , Proteínas Virais/genética , Sequência de Aminoácidos , Arthrobacter/química , Bacteriófagos/genética , Sequência de Bases , Clonagem Molecular , DNA Bacteriano , Escherichia coli/química , Lisogenia , Dados de Sequência Molecular , Mutagênese Insercional , Fases de Leitura Aberta , Mapeamento por Restrição , Alinhamento de Sequência , Análise de Sequência de DNA , Transfecção , Proteínas Virais/química , VirulênciaRESUMO
Four temperate bacteriophages of corynebacteria were isolated after UV induction. Phages phi 304L and phi 304S were both induced from Corynebacterium glutamicum ATCC 13058, ATCC 21488, ATCC 21649 and ATCC 21650 strains, and have no known sensitive host. Phages phi 15 and phi 16 were both induced from ATCC 14020 and ATCC 21792. Phage phi 15 formed turbid plaques on Corynebacterium sp. ATCC 21857 and on C. glutamicum ATCC 13058, ATCC 21488, ATCC 21649 and ATCC 21650. Phage phi 16 produced turbid plaques only on C. glutamicum ATCC 21792 cured of prophage phi 16. All these phages belong to the Siphoviridae family. Their genomes consist of a double-stranded DNA with cohesive ends and share no homology with each other. Prophages phi 16, phi 304L and phi 304S were integrated into their respective host chromosomes, whereas prophage phi 15 seemed to persist free in the cell. Cross-hybridizations between phage DNAs and total cellular DNA obtained from 20 strains belonging to the genera Corynebacterium and Brevibacterium did not show the presence of these prophages in strains other than their respective hosts.
Assuntos
Bacteriófagos/isolamento & purificação , Corynebacterium/virologia , DNA Bacteriano/isolamento & purificação , DNA Viral/isolamento & purificação , Lisogenia/fisiologia , Bacteriófagos/genética , Bacteriófagos/ultraestrutura , Corynebacterium/efeitos da radiação , DNA Bacteriano/química , DNA Bacteriano/genética , DNA Viral/química , DNA Viral/genética , Eletroforese em Gel de Campo Pulsado , Eletroforese em Gel de Poliacrilamida , Técnicas In Vitro , Microscopia Eletrônica , Hibridização de Ácido Nucleico , Raios Ultravioleta , Proteínas Estruturais Virais/químicaRESUMO
Arthrobacter aureus secretes 2 proteins of 22 and 100 kDa (P22 and P100, respectively). P22 is a protease, while P100, of unknown function, is associated with the cells before being released into the medium. An immunologically related P100 protein was also found in the culture supernatant of A. ureafasciens. Despite the fact that production of P22 and P100 proteins is induced by growth in the presence of bovine serum albumin, their synthesis is not always induced coordinately. Inactivation of the P100 chromosomal structural gene had no effect on growth characteristics of the mutant under inducing conditions.
