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Elements that excise and integrate, such as prophages, and transfer by conjugation, such as plasmids, have been found in various bacteria. These elements appear to have a diversified set of characteristics including cell-to-cell contact using pili or cell aggregation, transfer of single-stranded or double-stranded DNA, low or high specificity of integration(More)
Comparative analysis of the Streptomyces chromosome sequences, between Streptomyces coelicolor, Streptomyces avermitilis, and Streptomyces ambofaciens ATCC23877 (whose partial sequence is released in this study), revealed a highly compartmentalized genetic organization of their genome. Indeed, despite the presence of specific genomic islands, the central(More)
Streptococcus thermophilus is a major dairy starter used for the manufacture of yoghurt and cheese. The access to three genome sequences, comparative genomics and multilocus sequencing analyses suggests that this species recently emerged and is still undergoing a process of regressive evolution towards a specialised bacterium for growth in milk. Notably, S.(More)
The chromosomal structures of mutant strains of Streptomyces ambofaciens which have arisen from genetic instability were investigated by using pulsed-field gel electrophoresis and probing with sequences cloned from the unstable region which maps near the ends of the linear chromosomal DNA. The chromosomal structures of seven mutant strains harboring large(More)
Streptococcus thermophilus bacteria are used as a starter in the fermentation of yogurts and many cheeses. To construct mutants of S. thermophilus CNRZ368, the use of the plasmid pGh9:ISS1 was considered. This plasmid is known to be a good tool for insertional mutagenesis in gram-positive bacteria, owing to its ability to integrate in the genome by a(More)
Four highly amplified DNA sequences (ADS) ranging from 5.8 to 24.8 kb were found in spontaneous mutant strains of Streptomyces ambofaciens DSM 40697. Restriction patterns of total DNA were hybridized with purified ADS6 (24.8 kb) as a probe to detect the amplifiable regions in the wild-type (WT) genome. The results suggested that the amplifiable unit of DNA(More)
In the last few years many attempts have been made to differentiate more than 20 Bifidobacterium species. It has been recognized that identification of bifidobacterial species is problematic because of phenetic and genetic heterogeneities. In order to contribute to our understanding of Bifidobacterium taxonomy, we studied Bifidobacterium phylogeny by(More)
Streptomyces ambofaciens has an 8-Mb linear chromosome ending in 200-kb terminal inverted repeats. Analysis of the F6 cosmid overlapping the terminal inverted repeats revealed a locus similar to type II polyketide synthase (PKS) gene clusters. Sequence analysis identified 26 open reading frames, including genes encoding the beta-ketoacyl synthase (KS),(More)
In Streptomyces ambofaciens ATCC23877, pigment-negative (Pig-) mutants occur at high frequency (about 0.7 x 10(-2)) in the progenies of wild-type colonies. Furthermore, the offspring of these Pig- mutants can either be phenotypically homogeneous or hypervariable (with no preponderant phenotype). Pig- mutants can also lack antibiotic production and present(More)
A type II polyketide synthase gene cluster located in the terminal inverted repeats of Streptomyces ambofaciens ATCC 23877 was shown to be responsible for the production of an orange pigment and alpomycin, a new antibiotic probably belonging to the angucycline/angucyclinone class. Remarkably, this alp cluster contains five potential regulatory genes, three(More)