Data di Pubblicazione:
1996
Citazione:
Slow milk coagulating variants of Lactobacillus helveticus / M. Fortina, P. Rossi, D. Mora, C. Parini, E. Neviani. - In: FOLIA MICROBIOLOGICA. - ISSN 0015-5632. - 41:1(1996), pp. 33-38. [10.1007/BF02816337]
Abstract:
Curing experiments were performed onLactobacillus helveticus strain ATCC 15009 in order to find a correlation between the presence of three extrachromosomal elements and specific phenotypic traits. Mitomycin C treatment of the strain was found to result in an appearance of slow-coagulation variants unable to coagulate milk in 24 h at 42 °C. The effect of mitomycin C on phenotypic and genotypic characteristics ofL. helveticus was therefore further examined. The presence of mitomycin C appeared to act on the proteolytic system of the strain: slow variants exhibited a poor casein breakdown (50 % less) compared with the parental strain. Aminopeptidase activity and lactose utilization were unaffected. The phenotypic variation is possibly due to a point mutation of genetic patrimony. No loss of plasmid DNA was detected after mitomycin C treatment and the restriction pattern of plasmid and chromosomal DNA of the variants, after digestion with several restriction endonucleases, was identical to that obtained for the parental strain.
Tipologia IRIS:
01 - Articolo su periodico
Elenco autori:
M. Fortina, P. Rossi, D. Mora, C. Parini, E. Neviani
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