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Biomedical subjects

F Grimont

Publications and source records attributed to F Grimont.

99 records · Page 6Linked to original sources
PubMedDate not supplied

Identification of diary Propionibacterium species by rRNA gene restriction patterns.

A total of 78 strains of dairy propionibacteria, 4 reference strains of Propionibacterium and 8 related bacteria were characterized by ribosomal ribonucleic acid (rRNA) gene restriction patterns (ribotyping). The patterns were obtained after cleavage of total DNA with either BamHI or ClaI restriction endonucleases and hybridization of fragments with acetylaminofluorene-labelled 16 + 23S rRNA from Escherichia coli. The four different species of dairy propionibacteria, P. freudenreichii, P. jensenii, P. thoenii and P. acidipropionici, gave different restriction patterns with species-specific fragments. Moreover, ribotyping allowed the differentiation of P. freudenreichii subsp. freudenreichii from P. freudenreichii subsp. shermanii. The patterns of dairy propionibacteria were different from those of closely related bacteria and other bacteria used in the dairy industry.

Bacterial Typing Techniques↗
PubMedDate not supplied

Differentiation of Mycobacterium thermoresistibile from Mycobacterium phlei and other rapidly growing mycobacteria.

Mycobacterium thermoresistibile is the only chromogenic rapidly growing mycobacterial species reported to cause infections in humans and animals. DNA-DNA hybridization (S1 nuclease method) showed that M. thermoresistibile formed a DNA relatedness group which was only 24 to 30% related to M. phlei. Alkaline phosphatase and beta-galactosidase differentiated M. thermoresistibile from M. phlei. Among the rapidly growing mycobacteria, the mycolic acid pattern of M. thermoresistibile was unique (alpha-, alpha'-, methoxy-and keto-mycolates). Fourteen other species of chromogenic rapidly growing mycobacteria, including M. phlei, produced different mycolic acid patterns which always included dicarboxylic mycolate. Nine species of non-chromogenic rapidly growing mycobacteria produced mycolic acid patterns devoid of ketomycolate.

Alkaline Phosphatase↗
PubMedDate not supplied

Ribosomal ribonucleic acid gene restriction patterns as potential taxonomic tools.

Deoxyribonucleic acid from 41 different bacterial species (including Gram-negative and Gram-positive species) were cleaved by different restriction endonucleases, electrophoresed in agarose and transferred to nylon filters. The DNA fragments carrying rRNA genes (rDNA) were localized by hybridization with a 32P-labelled Escherichia coli 16 + 23S rRNA probe. A pattern of hybridized fragments was obtained for each DNA tested. Within a bacterial species (defined as a DNA hybridization group), one or several rDNA restriction patterns were observed. When DNA hybridization data were available, strains showing identical patterns were highly related with insignificant divergence. In a species, different patterns corresponded to significant divergence, as evaluated by thermal stability studies of DNA/DNA hybrids. Sets of rDNA restriction fragment sizes might constitute useful data for inclusion in species and type strain descriptions. Such data might later prove useful in identification of bacteria when biochemical characteristics are poor or atypical.

Bacteria↗
PubMedDate not supplied

Computer identification of Shigella species by rRNA gene restriction patterns.

We describe a MluI ribotyping scheme for Shigella which approaches correlation with serotyping. One hundred and seventeen reference strains and previously serotyped clinical isolates representing the 57 Shigella serotypes and biotypes were included in this study. A total of 51 distinct ribotypes were obtained and a database was built with them. The number of bands composing each ribotype varied from 9 to 15. The fragments ranged in size from 1.6 to 18.8 kbp. One hundred and eleven clinical isolates were successfully identified in a double blind study with standard biochemical/serologic methods, by automatic comparison of their ribotypes with our database using the software Taxotron.

Bacterial Proteins↗
PubMedDate not supplied

Comparison of 14 PCR systems for the detection and subtyping of stx genes in Shiga-toxin-producing Escherichia coli.

The specificity of 14 polymerase chain reaction (PCR) systems designed for the detection and subtyping of stx genes was tested on a set of Escherichia coli strains with known sequences of stx genes. Systems designed for the detection of genes of the stx1 type did not detect any variant genes of the stx2 type and conversely, no stx2 type-specific systems detected stx1 variant genes. Among five stx2 type-specific systems, none detected the stx2ev gene, and two detected the stx2e gene. Among systems designed for screening genes of the both stx1 and stx2 types with a single primer pair, only one system (the Lin system) was able to detect stx genes in all studied strains. Shiga-toxin-producing E. coli frequently carry more than one stx variant gene. Coamplification of stx genes present in the same strain was demonstrated by restriction of PCR products with endonucleases generating fragments of variant-specific size. The amplification product obtained by the Lin system restricted by Hincll yielded fragments of different size for stx1, stx2, stx2c, stx2e and stx2ev. Thus it was possible to identify different genes carried in a single strain with a simple two-step PCR/endonuclease restriction protocol.

Bacterial Toxins↗
PubMedDate not supplied

Molecular characterization of Vibrio cholerae O1 strains isolated in Romania.

A collection of 89 Vibrio cholerae O1 strains, isolated in Romania between 1977 and 1994, and 6 strains from the Republic of Moldavia, was characterized by ribotyping, toxin gene restriction pattern (toxinogenotype) and distribution of cholera toxin gene (ctx), accessory toxin gene (ace) and zonula occludens toxin gene (zot). After Bg/I endonuclease restriction of chromosomal DNA, a total of 18 ribotypes and 21 toxinogenotypes were distinguished. Deletions in the core region of the toxin gene cassette were found in 20% of strains; however, with the exception of one strain, all the isolates contained the ctx gene. Used in association, the three methods of molecular typing provided an accurate characterization of V. cholerae O1 isolates.

Bacterial Typing Techniques↗
PubMedDate not supplied

DNA from Mycobacterium leprae.

The cell walls of mycobacteria resisting all enzymatic and chemical methods for solubilization, good quality DNA require that they are converted into spheroplasts before extraction. Mycobacterium leprae cannot grow in laboratory media, spheroplasts cannot be induced, and therefore the bacteria must be ruptured using physical methods. In these investigations M. leprae was disrupted by sonication. The DNA isolated from sonicated M. smegmatis and sonicated purified DNA isolated from M. smegmatis spheroplasts were used as controls. Additional controls were DNA from E. coli K12 and DNA from armadillo liver. The DNA base compositions determined from melting curves were: armadillo liver, 37.99%; E. coli K12, 51.61%; M. smegmatis spheroplasts, 66.48%; purified sonicated DNA from M. smegmatis, 65.00%; and M. leprae, 66.96%.

DNA, Bacterial↗