Streptococcus mutants

Screening of Taiwanese crude drugs for antibacterial activity against Streptococcus mutants. J Ethnopharmacol 1989 27(3) 285-295. 

The probiotic strain E. faecium PR88 was studied in clinical trial (Allen et al. 1996). The consumption of this strain led to alleviation of the symptoms of irritable bowel syndrome in humans. The efficacy and safety of live combmedBifidobacterium, Lactobacillus and Enterococcus capsules in treatment of irritable bowel syndrome was also demonstrated (Fan et al. 2006). E. faecium functions as a probiotic strain inhibiting biofilm formation by Streptococcus mutants, which is an etiological agent for dental caries (Kumada et al. 2008). 

S.a = Staphylococcus aureus. B.s = Bacillus subtilis, M.s Mycobacterium smegma its, S.m = Streptococcus mutant, P.g.= Porphyromonas gingivalis, A.a = Actinobacillus aclinornycetencomitans, M 1 = Micrococcus lysodeikticus, S 1 = Saccharomyces cerevesiae, Cu = Candida unit s. S.l = Sckrotmia hbertiarm, M.l = Mucor muceclo, R.c - Rhizopus chinensis = >100, -= >.50... 

Hattori, M., K. Miyachi, Y.-Z. Shu, N, Kakiuchi, and T. Namba Studies on Dental Caries Prevention by Traditional Medicines. 9. Potent Antibacterial Action of Coumarin Derivatives from Licorice Roots against Streptococcus mutants. Shoyakugaku Zasshi (Jpn. J. Pharmacognosy), 40,406 (1986) Chem. Abstr., 107,46132a (1987). 

Hillman JD, Andrews SW and Dzuback AL (1987) Acetoin production by wild-type strains and a lactate dehydrogenase-deficient mutant of Streptococcus mutans. Infect Immun 55, 1399-1402. 

Guenzi, E. Case, A.M. Sicard, M.A. Hakenbeck, R. A two-component signal-transducing system is involved in competence and penicillin susceptibility in laboratory mutants of Streptococcus pneumoniae. Mol. Microbiol., 12, 505-515 (1994)... 

Cords, B. R. and McKay, L. L. 1974. Characterization of lactose-fermenting revertants from lactose-negative Streptococcus lactis C2 mutants. J. Bacteriol. 119, 830-839. 

McKay, L. L. and Baldwin, K. A. 1974. Altered metabolism in a Streptococcus lactis C2 mutant deficient in lactic dehydrogenase. J. Dairy Sci. 57, 181-185. 

Flurithromycin (120), a fluorinated erythromycin macrolide, has been isolated from a mutant strain of Streptomyces erythraeus. It shows antibacterial activity against Streptococcus pneumoniae (MIC 0.0015-... 

However, the first mutants which were recognized as affecting mismatch repair were found in bacteria. The hex mutant of Streptococcus (Diplococcus) pneumoniae, which increases the transformation rate of certain markers a hundred-fold, was found to be a mutator. Transformation in S. pneumoniae involves the uptake of a single strand of donor DNA and efficiency is limited by the correction of the mutational difference between donor and recipient. In /iex-mutants, the directionality of this correction is abolished (Lacks, 1970). Subsequently a number of... 

C Schuster, B Dobrinski, R Hakenbeck. Unusual septum formation in Streptococcus pneumoniae mutants with an alternation in the DD-carboxypeptidase penicillinbinding protein 3. J Bacteriol 172 6499-6505, 1990. 

A Severin, C Schuster, R Hakenbeck, A Tomasz. Altered murein composition in a DD-carboxypeptidase mutant of Streptococcus pneumoniae. J Bacteriol 174 5152-5155, 1992. 

G Laible, R Hakenbeck, MA Sicard, B Joris, JM Ghuysen. Nucleotide sequences of the pbpX genes encoding the penicillin-binding proteins 2x from Streptococcus pneumoniae R6 and a cefotaxime-resistant mutant, C506. Mol Microbiol 3 1337-1348, 1989. 

A Severin, MV Vaz Pato, AM Figureiredo, A Tomasz. Drastic changes in the peptidoglycan composition of penicillin-resistant laboratory mutants of Streptococcus pneumoniae. FEMS Microbiol Lett 130 31-35, 1995. 

To test the possibility that the carbamate kinase might be identical with acetokinase in other microorganisms, three deficient E. coli mutants, R185-823, R prototroph, and K -wt, known to have low carbamate kinase activity, were tested for acetyl-P utilization (17). Synthesis of ATP from acetyl-P occurred much faster than from carbamyl-P the ratios of activity for acetyl-P-carbamyl-P ranged from 8 to 20 on the other hand, the enzyme from streptococcus utilizes carbamyl-P twice as fast as acetyl-P this activity ratio. remained unchanged throughout a 40-fold purification of the enzyme (17). 

Blondeau JM, et al. Mutant prevention concentrations of fluoroquinolones for clinical isolates of Streptococcus pneumoniae. Antimicrob. Agents Chemother.,... 

Li X, Zhao X, Drlica K. Selection of Streptococcus pneumoniae mutants having reduced susceptibility to moxifloxacin and levofloxacin. Antimicrob. Agents Chemother., 2002, 46, 522-524. 

Changes in the nature or expression of penicillin-binding proteins (PBPs) render them insensitive to /3-lactam antibiotics although they can still be involved in peptidoglycan synthesis. Laboratory mutants of E. coli which are not killed by the mecillinam ester (33) have been described in these there is a reduced affinity of PBP2 for the antibiotic [165], More serious is the occurrence of this mechanism, involving PBP2b, in clinical isolates of Streptococcus pneumoniae [6]. 

Diacetyl reductase (acetoin dehydrogenase, 1.1.1.5) is widespread in bacteria (207, 208, 219, 220, 221), including the species (Streptococcus diacetilactis, Lactobacillus casei) used to prepare cultured dairy products. Mutants lacking diacetyl reductase also fail to synthesize diacetyl (222). The enzyme has been purified 30-fold from L. casei (223). The activity was not fully separable from an NADH oxidase activity, and the enzyme appeared to be a flavoprotein. Maximum activity was at pH 4.5. The NADH oxidase activity is associated with diacetyl reductase in other sources. 

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