scholarly journals Starvation Survival and Biofilm Formation under Subminimum Inhibitory Concentration of QAMs

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Sanjay Kumar Tiwari ◽  
Suping Wang ◽  
Yannan Huang ◽  
Xuedong Zhou ◽  
Hockin H. K. Xu ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Biofilm Formation ◽  
Acid Production ◽  
Inhibitory Concentration ◽  
Lactic Acid Production ◽  
Oral Bacteria ◽  
Laser Scanning Microscopy ◽  
Prolonged Starvation ◽  
Survival And Development ◽  
Development Of Tolerance

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.

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

2017 ◽  
Vol 84 (2) ◽  
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.

scholarly journals Streptococcus mutans and Actinomyces naeslundii Interaction in Dual-Species Biofilm

2020 ◽  
Vol 8 (2) ◽  
pp. 194 ◽  
Author(s):  
Rosa Virginia Dutra de Oliveira ◽  
Fernanda Salloume Sampaio Bonafé ◽  
Denise Madalena Palomari Spolidorio ◽  
Cristiane Yumi Koga-Ito ◽  
Aline Leite de Farias ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Streptococcus Mutans ◽  
Stress Responses ◽  
Acid Production ◽  
Flow Reactor ◽  
Lactic Acid Production ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Total Protein Content ◽  
Actinomyces Naeslundii

The study of bacterial interaction between Streptococcus mutans and Actinomyces naeslundii may disclose important features of biofilm interspecies relationships. The aim of this study was to characterize—with an emphasis on biofilm formation and composition and metabolic activity—single- and dual-species biofilms of S. mutans or A. naeslundii, and to use a drip flow reactor (DFR) to evaluate biofilm stress responses to 0.2% chlorhexidine diacetate (CHX). Single- and dual-species biofilms were grown for 24 h. The following factors were evaluated: cell viability, biomass and total proteins in the extracellular matrix, 2,3-bis(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide—“XTT”—reduction and lactic acid production. To evaluate stress response, biofilms were grown in DFR. Biofilms were treated with CHX or 0.9% sodium chloride (NaCl; control). Biofilms were plated for viability assessment. Confocal laser-scanning microscopy (CLSM) was also performed. Data analysis was carried out at 5% significance level. S. mutans viability and lactic acid production in dual-species biofilms were significantly reduced. S. mutans showed a higher resistance to CHX in dual-species biofilms. Total protein content, biomass and XTT reduction showed no significant differences between single- and dual-species biofilms. CLSM images showed the formation of large clusters in dual-species biofilms. In conclusion, dual-species biofilms reduced S. mutans viability and lactic acid production and increased S. mutans’ resistance to chlorhexidine.

scholarly journals Protective effect of titanium tetrafluoride and silver diamine fluoride on radiation-induced dentin caries in vitro

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Beatriz Martines de Souza ◽  
Mayara Souza Silva ◽  
Aline Silva Braga ◽  
Patrícia Sanches Kerges Bueno ◽  
Paulo Sergio da Silva Santos ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Protective Effect ◽  
Acid Production ◽  
Lactic Acid Production ◽  
Negative Control ◽  
Titanium Tetrafluoride ◽  
Silver Diamine Fluoride ◽  
Dentin Caries ◽  
Radiation Induced

AbstractThis in vitro study evaluated the protective effect of titanium tetrafluoride (TiF4) varnish and silver diamine fluoride (SDF) solution on the radiation-induced dentin caries. Bovine root dentin samples were irradiated (70 Gy) and treated as follows: (6 h): 4% TiF4 varnish; 5.42% NaF varnish; 30% SDF solution; placebo varnish; or untreated (negative control). Microcosm biofilm was produced from human dental biofilm (from patients with head-neck cancer) mixed with McBain saliva for the first 8 h. After 16 h and from day 2 to day 5, McBain saliva (0.2% sucrose) was replaced daily (37 °C, 5% CO2) (biological triplicate). Demineralization was quantified by transverse microradiography (TMR), while biofilm was analyzed by using viability, colony-forming units (CFU) counting and lactic acid production assays. The data were statistically analyzed by ANOVA (p < 0.05). TiF4 and SDF were able to reduce mineral loss compared to placebo and the negative control. TiF4 and SDF significantly reduced the biofilm viability compared to negative control. TiF4 significantly reduced the CFU count of total microorganism, while only SDF affected total streptococci and mutans streptococci counts. The varnishes induced a reduction in lactic acid production compared to the negative control. TiF4 and SDF may be good alternatives to control the development of radiation-induced dentin caries.

scholarly journals Lactic acid production ability of Lactobacillus sp. from four tropical fruits using their by-products as carbon source

Heliyon ◽  
2021 ◽  
Vol 7 (5) ◽  
pp. e07079
Author(s):  
Joel Romial Ngouénam ◽  
Chancel Hector Momo Kenfack ◽  
Edith Marius Foko Kouam ◽  
Pierre Marie Kaktcham ◽  
Rukesh Maharjan ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Carbon Source ◽  
Acid Production ◽  
Lactic Acid Production ◽  
Tropical Fruits ◽  
By Products

γ-Valerolactone-Introduced Controlled-Isomerization of Glucose for Lactic Acid Production over Sn-Beta Catalyst

2021 ◽  
Author(s):  
Xinpeng Zhao ◽  
Zhimin Zhou ◽  
hu luo ◽  
Yanfei Zhang ◽  
Wang Liu ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Lactic Acid ◽  
Dft Calculations ◽  
Acid Production ◽  
Density Functional ◽  
Lactic Acid Production ◽  
Hydrothermal Conversion ◽  
Functional Theory ◽  
Environment Friendly

Combined experiments and density functional theory (DFT) calculations provided insights into the role of the environment-friendly γ-valerolactone (GVL) as a solvent in the hydrothermal conversion of glucose into lactic acid...

Impact of storage duration and micro-aerobic conditions on lactic acid production from food waste

2021 ◽  
Vol 323 ◽  
pp. 124618
Author(s):  
Zengshuai Zhang ◽  
Panagiotis Tsapekos ◽  
Merlin Alvarado-Morales ◽  
Irini Angelidaki
Keyword(s):  
Lactic Acid ◽  
Food Waste ◽  
Acid Production ◽  
Lactic Acid Production ◽  
Storage Duration ◽  
Aerobic Conditions
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