Article Abstract:
Additive effects of two substitutions in dihydropteroate synthase (DHPS) for the development of sulfonamide-resistant Neisseria meningitidis are discussed. A two-amino-acid insertion and a single-amino-acid substitution, together, give new resistance, the gene for which may have been introduced by natural transformation. It was found that a normal chromosomally encoded DHPS of N. meningitidis cannot be changed to one that is sulfonamide-resistant by inserting a serine and glycine, as is seen in clinical isolates. Likely the resistance gene in the isolates evolved in another bacterial species.
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Article Abstract:
Examination of the influence of various fermentation processes on the bactericidal activity of lactocin S, a lantibiotic from Lactobacillus sake L45 reveals that bacteriocin activity is maximum during the early stationary growth phase of cultures at 30 degrees Celsius. Production of bacteriocin is higher at pH5 compared with production during batch culture fermentation. Addition of 1% ethanol increases the yield of bacteriocin. The pH of the culture influences the killing of target cells mediated by lactocin S.
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Article Abstract:
Lactobacillus sakei is discussed relative to a transposition and inactivation of a second lactocin S operon by insertion of IS1520. IS1520 is a new member of the IS3 insertion sequences family. The new transpositionally active insertion sequence encodes two consecutive partially overlapping major ORFs. They are frameshifted in a way that is typical of the IS3 family.
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