Isolation and characterization of the substance isolated from Streptosporangium species which inhibits lactic acid production by oral bacteria

Quaternary ammonium methacrylates (QAMs) are useful antimicrobial compounds against oral bacteria. Here, we investigated the effects of two QAMs, dimethylaminododecyl methacrylate (DMADDM) and dimethylaminohexadecyl methacrylate (DMAHDM), on biofilm formation, survival and development of tolerance by biofilm, and survival and development of tolerance against QAMs after prolonged starvation. Enterococcus faecalis (E. faecalis), Streptococcus gordonii (S. gordonii), Lactobacillus acidophilus (L. acidophilus), and Actinomyces naeslundii (A. naeslundii) were used. Minimum inhibitory concentration (MIC) of QAMs against multispecies biofilm was determined. Biofilm formed under sub-MIC was observed by crystal violet staining and confocal laser scanning microscopy (CLSM). Metabolic activity was assessed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and lactic acid production measurement. Development of tolerance was determined by MIC values before and after exposure to QAMs or after prolonged starvation. It was found that E. faecalis and S. gordonii could survive and form biofilm under sub-MIC of QAMs. Lactic acid production from biofilms formed under sub-MIC was significantly higher than control specimens ( p < 0.05 ). The exposure to sub-MIC of QAMs promoted biofilm formation, and prolonged starvation or prolonged contact with sub-MIC helped bacteria develop tolerance against killing by QAMs.

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Characterization of yeasts with highL[+]-lactic acid production: Lactic acid specific soft-agar overlay (LASSO) and TAFE-patterns

Journal of Basic Microbiology ◽

10.1002/jobm.3620291014 ◽

1989 ◽

Vol 29 (10) ◽

pp. 707-716 ◽

Cited By ~ 15

Author(s):

V. Witte ◽

U. Krohn ◽

C. C. Emeis

Keyword(s):

Lactic Acid ◽

Acid Production ◽

Lactic Acid Production ◽

Soft Agar

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Plasticity of the Pyruvate Node Modulates Hydrogen Peroxide Production and Acid Tolerance in Multiple Oral Streptococci

Applied and Environmental Microbiology ◽

10.1128/aem.01697-17 ◽

2017 ◽

Vol 84 (2) ◽

Cited By ~ 8

Author(s):

Xingqun Cheng ◽

Sylvio Redanz ◽

Nyssa Cullin ◽

Xuedong Zhou ◽

Xin Xu ◽

...

Keyword(s):

Lactic Acid ◽

Environmental Conditions ◽

Dental Plaque ◽

Acid Production ◽

Lactic Acid Production ◽

Acid Tolerance ◽

Oral Bacteria ◽

Low Ph ◽

Content Type ◽

Pyruvate Node

ABSTRACTCommensalStreptococcus sanguinisandStreptococcus gordoniiare pioneer oral biofilm colonizers. Characteristic for both is the SpxB-dependent production of H2O2, which is crucial for inhibiting competing biofilm members, especially the cariogenic speciesStreptococcus mutans. H2O2production is strongly affected by environmental conditions, but few mechanisms are known. Dental plaque pH is one of the key parameters dictating dental plaque ecology and ultimately oral health status. Therefore, the objective of the current study was to characterize the effects of environmental pH on H2O2production byS. sanguinisandS. gordonii.S. sanguinisH2O2production was not found to be affected by moderate changes in environmental pH, whereasS. gordoniiH2O2production declined markedly in response to lower pH. Further investigation into the pyruvate node, the central metabolic switch modulating H2O2or lactic acid production, revealed increased lactic acid levels forS. gordoniiat pH 6. The bias for lactic acid production at pH 6 resulted in concomitant improvement in the survival ofS. gordoniiat low pH and seems to constitute part of the acid tolerance response ofS. gordonii. Differential responses to pH similarly affect other oral streptococcal species, suggesting that the observed results are part of a larger phenomenon linking environmental pH, central metabolism, and the capacity to produce antagonistic amounts of H2O2.IMPORTANCEOral biofilms are subject to frequent and dramatic changes in pH.S. sanguinisandS. gordoniican compete with caries- and periodontitis-associated pathogens by generating H2O2. Therefore, it is crucial to understand howS. sanguinisandS. gordoniiadapt to low pH and maintain their competitiveness under acid stress. The present study provides evidence that certain oral bacteria respond to environmental pH changes by tuning their metabolic output in favor of lactic acid production, to increase their acid survival, while others maintain their H2O2production at a constant level. The differential control of H2O2production provides important insights into the role of environmental conditions for growth competition of the oral flora.

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Isolation and Plasmid Characterization of a Lactobacillus Species Involved in the Manufacture of Fermented Sausage1

Journal of Food Protection ◽

10.4315/0362-028x-48.12.1028 ◽

1985 ◽

Vol 48 (12) ◽

pp. 1028-1035 ◽

Cited By ~ 7

Author(s):

DENNIS A. ROMERO ◽

LARRY L. McKAY

Keyword(s):

Lactic Acid ◽

Polyethylene Glycol ◽

Plasmid Dna ◽

Acid Production ◽

Gas Production ◽

Lactobacillus Species ◽

Erythromycin Resistance ◽

Streptococcus Lactis ◽

Isolation And Characterization

Isolation and characterization of a Lactobacillus species capable of proper acid production in a sausage environment is described. The isolate from sausage, categorized as a lactobacillus in the subgenus Streptobacterium, was designated Lactobacillus sp. DR1. Growth occurred at 5 and 42°C but not at 45°C. Fructose, galactose, glucose, mannose, melibiose, N-acetylglucosamine, ribose, sucrose and trehalose were fermented. Gas production from glucose was not observed. In MRS glucose broth, D(−) and L(+) lactic acid were produced. Lactobacillus sp. DR1 contained a single cryptic plasmid of approximately 30 megadaltons (Mdal). In sausage fermentation trials, both Lactobacillus sp. DR1 and plasmid-free derivative DR1C lowered the pH to below 5.3 after 8 h in the smokehouse. Conjugation was demonstrated through the transfer of plasmid pAMβ1, which encodes erythromycin resistance, from Streptococcus lactis 2301β to Lactobacillus sp. DR1. Mutanolysin-generated protoplasts could be regenerated using 0.5 M ammonium chloride, lactose, maltose or sucrose as osmotic stabilizers. Regeneration frequencies ranged from less than 1.0% up to 35%; however, transformation of Lactobacillus sp. DR1 protoplasts by plasmid DNA in the presence of polyethylene glycol (PEG) was unsuccessful.

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