A polyphasic approach to highlight genotypic and phenotypic diversities of Lactobacillus helveticus strains isolated from dairy starter cultures and cheeses.
In the present work, 67 strains of Lactobacillus helveticus isolated from whey starter cultures and cheeses were identified and grouped by genotypic and phenotypic methods. Strains were identified by sugar fermentation pattern, by cell-wall protein profile, and by probe hybridisation. Phenotypic diversity was evaluated by a chemometric model taking into account biochemical characteristics (i.e. acidifying and peptidase activities) of technological interest. Genotypic diversity was evidenced by RAPD-PCR, which provided stran-specific patterns and revealed the occurrence of different strains. The RAPD-PCR profiles were clustered according to their similarities: the groups obtained, together with the cell-wall protein profiling and the chemometric information, could be sometimes correlated with the type of cheese and/or dairy niches used as sources of strains. A computerised analysis of genotypic and phenotypic information could be successfully applied for rapid and reliable differentiation and characterisation of Lb. helveticus isolates occurring in different dairy products.
Lombardi
Angiolella
A
Veneto Agricoltura, Istituto per la Qualità e le Tecnologie Agroalimentari, Thiene (VI), Italy. angiolella.lombardi@venetoagricoltura.org
Maistro
Luciana Dal
LD
De Dea
Paola
P
Gatti
Monica
M
Giraffa
Giorgio
G
Neviani
Erasmo
E
D000818:Animals; D001426:Bacterial Proteins / Q000032:analysis; D015373:Bacterial Typing Techniques / Q000379:methods; D050260:Carbohydrate Metabolism; D002611:Cheese / Q000382:microbiology*; D016000:Cluster Analysis; D016172:DNA Fingerprinting; D004269:DNA, Bacterial / Q000032:analysis*; D003611:Dairy Products / Q000382:microbiology*; D005285:Fermentation; D014644:Genetic Variation; D005838:Genotype; D007778:Lactobacillus / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification; D010641:Phenotype; D019105:Random Amplified Polymorphic DNA Technique / Q000379:methods; D013045:Species Specificity
D001426:Bacterial Proteins; D004269:DNA, Bacterial