DNA relatedness among strains of Streptomyces pathogenic to potato in France: description of three new species, S. europaeiscabiei sp. nov. and S. stelliscabiei sp. nov. associated with common scab, and S. reticuliscabiei sp. nov. associated with netted scab.

The genomic relatedness was evaluated by DNA-DNA hybridization for 23 strains (21 were pathogenic and two were saprophytic strains) isolated from lesions of common and netted scab in France and 19 strains from other countries, including type strains of Streptomyces species. Three genomospecies were defined within the conventional species of Streptomyces scabies, and these genomospecies were different from other pathogenic described species (Streptomyces acidiscabies, Streptomyces caviscabies) based on previously published phenotypic data. Two of these genomospecies (1 and 3) correspond to new species, for which the names Streptomyces europaeiscabiei sp. nov. (with type strain CFBP 4497T) and Streptomyces stelliscabiei sp. nov. (with type strain CFBP 4521T) are proposed. Genomospecies 2 corresponds to S. scabies (with type strain CFBP 4517T = ATCC 49173T), and includes only one French strain. The pathogenic strains associated with netted scab lesions constituted a new species that was named Streptomyces reticuliscabiei sp. nov. (with type strain CFBP 4531T). The G+C content of DNA from the three strains CFBP 4497T (S. europaeiscabiei), CFBP 4521T (S. stelliscabiei), CFBP 4531T (S. reticuliscabiei) was 71.3, 71.0 and 69.8 mol%, respectively. Phylogenetic analysis based on 16S rRNA gene sequences showed that the type strain CFBP 4497T was very similar to the type strain of S. scabies, whereas, the type strain of S. stelliscabiei, CFBP 4521T, was very similar to the type strain of Streptomyces bottropensis. On the basis of 16S rRNA gene sequences, the type strain of S. reticuliscabiei, CFBP 4531T, differed extensively from the other strains of Streptomyces tested.

Digital mammography performed with computed radiography technology.

Introduced by Fuji Photo Film Japan in the early 1980s, computed radiography (CR) technology has developed considerably since then to become the mature widely installed technology it is today (about 7500 systems worldwide). Various mammographic examinations require high performance results to which CR complies on demand or following some procedures such as geometrical magnification carried out during the examination. The basic CR principles and digital image processing as well as technical improvements are detailed in this study, which also includes a synthesis of the articles on CR mammographic applications referenced in the bibliography, focusing on strong points, limits and current methods of surpassing these limits. New CR technology development perspectives in mammography and computed assisted diagnosis (CAD) algorithms will allow wider use of this method in the near future.

Streptomyces species isolated from potato scabs in France: numerical analysis of "Biotype-100" carbon source assimilation data.

Thirty one strains of Streptomyces isolated from common and netted scabs in France were characterized using "Biotype-100" strips and 14 conventional tests. Numerical analysis showed that S. scabiei was the single causal agent of common scab in France. However the strains clustered among S. scabiei were phenotypically heterogeneous, since 3 subphenons were delineated. The strains clustered in subphenons 1a and 1c and one strain of subphenon 1b were associated with common scab. On the other hand, a group of strains clustered in phenon 2, distinct from S. scabiei, S. acidiscabies and S. caviscabies, was often associated with symptoms of netted scab. None of the French strains thus far pathogenic to potato belonged to the already described species S. acidiscabies and S. caviscabies from Japan and North America. Phenotypic characteristics clearly differentiated all the various groups of strains described.