Biomedical subjects

Michel Linder

Publications and source records attributed to Michel Linder.

3 recordsLinked to original sources

PubMed2006

A selective enumeration medium for Carnobacterium maltaromaticum.

A selective medium was proposed for isolating the species Carnobacterium maltaromaticum from cheeses. This medium, named CM, was elaborated using combinations of three antibiotics (gentamicin, nalidixic acid, vancomycin) and alkaline pH value (8.8). An experimental design (Doehlert matrix) was drawn up to optimize the experimental conditions of the preparation of the medium. Based on the TS-YE agar medium, it contained 3.5 mg L(-1) of vancomycin, 5.0 mg L(-1) of gentamicin, and 20 mg L(-1) of nalidixic acid. The incubation time was 36 to 48 h at 25 degrees C. The selectivity of this medium was tested against bacterial strains present in the dairy industry and controlled by the PCR method. Thanks to this medium, it was easy to detect C. maltaromaticum and to follow this species in the cheese-making process.

Anti-Bacterial Agents↗

PubMed2005

Proteolytic extraction of salmon oil and PUFA concentration by lipases.

Commercial proteases (Alcalase, Neutrase, and Flavourzyme) were tested for their ability to release the oil content of marine by-products (salmon heads). The amount of oil (17%) obtained after 2 hours was close to that obtained by the chemical extraction method (20%). Lipolysis of the oil was carried out with Novozym SP398 to obtain a mixture of free fatty acids and acylglycerols (24 hours 45% hydrolysis). The mixture was filtered on a hydrophobic membrane to discriminate between high melting saturated fatty acids and low melting acylglycerols. The sum of total polyunsaturated fatty acids increased from 41.6% in the crude oil to 46.5% in the permeate. The docosahexaenoic acid content increased from 9.9% to 11.6%, and the eicosapentaenoic acid changed from 3.6% to 5.6%. Data from differential scanning calorimetry DSC and from thin layer chromatography coupled with flame ionization detection (TLC-FID) differed significantly between permeate and retentate. A re-esterification of the free fatty acids in the permeate with Lipozyme IM was carried out to increase the amount of long chain acylglycerols.

Animals↗

PubMed2004

Cell envelope analysis of insensitive, susceptible or resistant strains of Leuconostoc and Weissella genus to Leuconostoc mesenteroides FR 52 bacteriocins.

Mesenterocins 52A and 52B belong to class II of lactic acid bacteria bacteriocins. To study susceptibility, insensitivity and resistance to these mesenterocins, four wild-type bacterial strains and four resistant strains, all from Leuconostoc or Weissella genus, were compared. Several cell envelope features were investigated: susceptibilities to antibiotics and to lysozyme, cell morphology and membrane phospholipids contents. The strain insensitive to the two mesenterocins appeared to be resistant to lysozyme and exhibited the highest resistance to antibiotics. Resistant strains displayed cell morphology modifications, several increases in antibiotic resistance and modifications in lysozyme susceptibility. Moreover, mesenterocin 52A-resistant strains displayed modifications in their membrane phospholipids, leading to a more cationic membrane. Insensitivity and resistance of Leuconostoc or Weissella strains seem to be due to various minor modifications of the membrane and/or of the cell wall.

Anti-Bacterial Agents↗