Metabolic and proteomic adaptation of Lactobacillus rhamnosus strains during growth under cheese-like environmental conditions compared to de Man, Rogosa, and Sharpe medium.

The aim of this study was to demonstrate the metabolic and proteomic adaptation of Lactobacillus rhamnosus strains, which were isolated at different stages of Parmigiano Reggiano cheese ripening. Compared to de Man, Rogosa, and Sharpe (MRS) broth, cultivation under cheese-like conditions (cheese broth, CB) increased the number of free amino acids used as carbon sources. Compared with growth on MRS or pasteurized and microfiltrated milk, all strains cultivated in CB showed a low synthesis of d,l-lactic acid and elevated levels of acetic acid.

A polyphasic approach to detect enterotoxigenic Staphylococcus aureus and diarrheagenic Escherichia coli in raw milk Italian cheeses by multiplex PCR.

A polyphasic approach was evaluated for the detection of eight staphylococcal enterotoxin (SE)-encoding genes (sea, sec, sed, seg, seh, sei, sej, sel) and the Escherichia coli genes most commonly associated with virulence factors (eae, elt, ipaH, stx) in traditional soft cheeses, manufactured artisanally from whole raw milk in the Lombardy region (northern Italy). To determine the presence of the target genes, two multiplex PCRs were performed on DNA extracted both directly from cheese samples (culture-independent approach) and from whole cultivable cells, formed by harvesting colonies from the first serial dilution agar plates of selective media, as representative of cultivable community ("bulk"). Genes associated with enteroinvasive E.

Evaluation of genetic polymorphism among Lactobacillus rhamnosus non-starter Parmigiano Reggiano cheese strains.

Parmigiano Reggiano (PR) is an Italian cooked, long-ripened cheese made with unheated cow's milk and natural whey starter. The microflora is involved in the manufacturing of this cheese, arising from the natural whey starter, the raw milk and the environment. Molecular studies have shown that mesophilic non-starter lactic acid bacteria (NSLAB) are the dominant microflora present during the ripening of PR.

Application of AFLP fingerprint analysis for studying the biodiversity of Streptococcus thermophilus.

Streptococcus thermophilus is a lactic acid bacteria (LAB) widely used in milk fermentation processes as a starter culture. In this work the genetic diversity of S. thermophilus isolates from different sources was analyzed using Amplified Fragment Length Polymorphism fingerprinting (AFLP).

Mutation D104G in ANT1 gene: complementation study in Saccharomyces cerevisiae as a model system.

Mutations in the human ANT1 gene, coding for the ADP/ATP carrier, are responsible for the autosomal dominant and recessive forms of progressive external ophthalmoplegia, mitochondrial disorders characterized by the presence of multiple deletions of mitochondrial DNA in affected tissues. By introducing these mutations at equivalent position in AAC2, the yeast orthologue of ANT1, we created a suitable model for validation of the pathogenicity of the human mutations. Here, we describe the use of this approach in the case of mutations mapping in domains not conserved between human and yeast, taking advantage of a yAAC2/hANT1 chimeric construction as a template to introduce pathogenic hANT1 mutations.