Thirty-eight strains of Lactobacillus helveticus, including 26 strains of L. helveticus biotype jugurti, were isolated from natural starters for Grana cheese. Seventeen strains had diaminopimelic acid (DAP) as a cytoplasmic (but not cell wall) component; 21 strains did not contain DAP. DAP-positive and galactose-negative strains may constitute new biotypes of L. helveticus. Despite these variations, all of the strains studied displayed high deoxyribonucleic acid (DNA)-DNA homologies to the reference DNA, and the presence or absence of DAP is not considered to be of great taxonomic importance in L. helveticus.
BottazziV.,
VescovoM.,
DellaglioF.1973; Ricerche sulla microbiologia del formaggioGrana. Parte IX. Caratteri e distribuzione dei biotipi di L. helveticus nelle colture associate naturali (siero-fermento). Sci. Technol. Latt.-Cas 24:23–39
De LeyJ.1970; Reexamination of the association between melting point, buoyant density, and chemical base composition of deoxyribonucleic acid. J. Bacteriol 101:738–754
DellaglioF.,
BottazziV.,
TrovatelliL.D.1973; Deoxyribonucleic acid homology and base composition in some thermophilic lactobacilli. J. Gen. Microbiol 74:289–297
HansenP.A.1968; Type strains of Lactobacillus species. Report by the Taxonomic Subcommittee on Lactobacilli and Closely Related Organisms. American Type Culture Collection; Rockville, Md:
HoareD.S.,
WorkE.1957; The stereoisomers of α-e diaminopimelic acid. II. Their distribution in the bacterial order Actinomy- cetales and in certain Eubacteriales. Biochem. J 65:441–447
JohnsonJ.L.,
OrdalE.J.1968; Deoxyribonucleic acid homology in bacterial taxonomy: effect of incubation temperature on reaction specificity. J. Bacteriol 95:893–900
MatteuzziD.1967; Studi sulla microflora dei siero-innesti del formaggio parmigiano-reggiano. Distribuzione biometrica dei caratteri “potere proteolitico” e “potere acidogeno” nella specie Lactobacillus jugurti. Ann. Microbiol 17:211–219
MillerA.,
SandineW.E.,
EllikerP.R.
III 1970; Deoxyribonucleic acid base composition of lactobacilli determined by thermal denaturation. J. Bacteriol 102:278–280
VescovoM.,
BottazziV.,
DellaglioF.,
BattistottiB.1971; Su alcuni caratteri culturali e morfologici di ceppi di Lactobacillus jugurti. Ann. Microbiol 21:15–23