A GROWTH-STIMULATING FACTOR FOR LACTOBACILLUS LEICHMANNII

The nutritional requirements of Lactobacillus bifidus and Lactobacillus leichmannii.

Purification and characterization of dihydrofolate reductase from Lactobacillus leichmannii.

Dihydrofolate reductase (DHFR) (5,6,7,8-THF: NADDP+ oxidoreductase, EC 1.5.1.3) was purified 205-fold to apparent homogeneity from the crude extracts of Lactobacillus leichmannii. It has UV absorption maxima at 280 nm, M(r) of 20,000, Stokes radius of 0.34 nm and a S20.w value of 0.12 S. The preparation showed the presence of 168 amino acid residues with threonine and lysine as the NH2- and COO...

Survival of Lactobacillus Leichmannii in Relation to Vitamin B12 Assays.

Since washed cells of Lactobacillus leichmannii ATCC 7830 frequently showed erratic results in vitamin B(12) assays, a depletion technique was used to stabilize the inoculum. The method consisted of incubating the twice-washed cells at 37 C for 45 min in distilled water. Survival and growth studies indicated that the stabilizing procedure (i) did not affect cell numbers, (ii) was optimal for de...

Inactivation of Lactobacillus leichmannii ribonucleotide reductase by F2CTP: covalent modification

Ribonucleotide reductase (RNR) from Lactobacillus leichmannii, a 76 kDa monomer using adenosylcobalamin (AdoCbl) as a cofactor, catalyzes the conversion of nucleoside triphosphates to deoxynucleotides and is rapidly (<30 sec) inactivated by one equivalent (eq.) of 2′,2′-difluoro-2′deoxycytidine 5′-triphosphate (F2CTP). [1′-3H] and [5-H]-F2CTP were synthesized and used independently to inactivat...

THE MICROBIOLOGICAL ASSAY OF VITAMIN Bu WITH LACTOBACILLUS LEICHMANNII