Interspecies competition and inhibition within the oral microbial flora: environmental factors influence the inhibition of Streptococcus mutans by Streptococcus oligofermentans

2012 ◽  
Vol 120 (3) ◽  
pp. 179-184 ◽  
Author(s):  
Ying Liu ◽  
Ligeng Wu ◽  
Fei Wu ◽  
Lei Chu ◽  
Xinxin Liu ◽  
...  
Keyword(s):  
Environmental Factors ◽  
Streptococcus Mutans ◽  
Microbial Flora ◽  
Interspecies Competition

scholarly journals Function of the Pyruvate Oxidase-Lactate Oxidase Cascade in Interspecies Competition between Streptococcus oligofermentans and Streptococcus mutans

2012 ◽  
Vol 78 (7) ◽  
pp. 2120-2127 ◽  
Author(s):  
Lei Liu ◽  
Huichun Tong ◽  
Xiuzhu Dong
Keyword(s):  
Stationary Phase ◽  
Streptococcus Mutans ◽  
Growth Phase ◽  
Large Degree ◽  
Interspecies Interactions ◽  
Lactate Oxidase ◽  
Interspecies Competition ◽  
Pyruvate Oxidase ◽  
Content Type

ABSTRACTComplex interspecies interactions occur constantly between oral commensals and the opportunistic pathogenStreptococcus mutansin dental plaque. Previously, we showed that oral commensalStreptococcus oligofermentanspossesses multiple enzymes for H2O2production, especially lactate oxidase (Lox), allowing it to out-competeS. mutans. In this study, through extensive biochemical and genetic studies, we identified a pyruvate oxidase (pox) gene inS. oligofermentans. Apoxdeletion mutant completely lost Pox activity, while ectopically expressedpoxrestored activity. Pox was determined to produce most of the H2O2in the earlier growth phase and log phase, while Lox mainly contributed to H2O2production in stationary phase. Bothpoxandloxwere expressed throughout the growth phase, while expression of theloxgene increased by about 2.5-fold when cells entered stationary phase. Since lactate accumulation occurred to a large degree in stationary phase, the differential Pox- and Lox-generated H2O2can be attributed to differential gene expression and substrate availability. Interestingly, inactivation ofpoxcauses a dramatic reduction in H2O2production from lactate, suggesting a synergistic action of the two oxidases in converting lactate into H2O2. In anin vitrotwo-species biofilm experiment, thepoxmutant ofS. oligofermentansfailed to inhibitS. mutanseven thoughloxwas active. In summary,S. oligofermentansdevelops a Pox-Lox synergy strategy to maximize its H2O2formation so as to win the interspecies competition.

Environmental factors that affect Streptococcus mutans biofilm formation in a microfluidic device mimicking teeth

2010 ◽  
Vol 4 (4) ◽  
pp. 257-263 ◽  
Author(s):  
Wahhida Shumi ◽  
Jeesun Lim ◽  
Seong-Won Nam ◽  
Kangmu Lee ◽  
So Hyun Kim ◽  
...  
Keyword(s):  
Environmental Factors ◽  
Streptococcus Mutans ◽  
Microfluidic Device ◽  
Biofilm Formation

Identification of some Pathogenic Organisms Involved in Rotting of the Libyan Tirmania Truffles

2021 ◽  
pp. 109-116
Author(s):  
Mohammed Ahmed Emhmed
Keyword(s):  
Environmental Factors ◽  
Ectomycorrhizal Fungi ◽  
Fusarium Solani ◽  
Bacillus Pumilus ◽  
Fruit Body ◽  
Microbial Flora ◽  
Saprophytic Fungi ◽  
Desert Truffle ◽  
Libyan Desert ◽  
Desert Truffles

Truffles are ectomycorrhizal fungi that grow symbiotically with several trees. Truffles are highly valued edible mycorrhizae fungi in economic and gastronomic terms. Desert truffles have been traditionally used as food in Libya. The rotting of truffle due to environmental factors is very common in Libya. The mechanism of truffle rot is complex and attributed mainly due to the infection with fungi, followed by bacteria. In order to document and highlight the rotting of Libyan Desert truffle phenomenon, the existence of microorganisms in the infected fruit body of Tirmania truffles has been investigated. The investigations showed changes in physical characteristics such as color, hardness, and humidity of the studied truffle samples. Also, the results showed a diversity of pathogens involved in the deterioration of truffle includes bacteria (Bacillus pumilus, Citrobacteryoungea), saprophytic fungi (Fusarium solani, Alternariachlamydosporia, and Rhizopusstolonifer). This study concluded the importance of studying microbial flora living in truffle and their environment. Keywords: Libyan Desert truffle; Tirmania; Rotting; Pathogens

Virulence of Streptococcus mutans: An Antibiotic-Suppressed Rat Model for Studies of Pathogenesis

1977 ◽  
Vol 56 (3) ◽  
pp. 205-211 ◽  
Author(s):  
Suzanne M. Michalek ◽  
Jerry R. McGhee
Keyword(s):  
Streptococcus Mutans ◽  
Rat Model ◽  
Microbial Flora ◽  
Rat Pups ◽  
Test Microorganism

A simple and effective method of antibiotic suppression of the total indigenous microbial flora of rat dams and their offspring has been developed. This method allowed more effective challenge and subsequent colonization of wean-ling rat pups with a test Streptococcus mutans, since S mutans 6715 was isolated from 95% of the treated rats and only 50% of the non-treated offspring following challenge with a single inoculum of this test microorganism.

Factors Influencing the Competition between Streptococcus oligofermentans and Streptococcus mutans in Dual-Species Biofilms

2017 ◽  
Vol 51 (5) ◽  
pp. 507-514 ◽  
Author(s):  
Xudong Bao ◽  
Jingmei Yang ◽  
J.J. de Soet ◽  
Hongyan Liu ◽  
Xuejun Gao ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Lactic Acid ◽  
Environmental Factors ◽  
Streptococcus Mutans ◽  
Lactic Acid Production ◽  
Hydrogen Peroxide Production ◽  
Neutral Ph ◽  
Cell Counts ◽  
Ph Conditions

Previous studies have shown that Streptococcus oligofermentans inhibits the growth of cariogenic Streptococcus mutans in biofilms in vitro and is considered a probiotic candidate for caries prevention. This study aimed to examine the effects of various environmental factors on the competition between S. oligofermentans and S. mutans in a dual-species biofilm model. Single or dual S. oligofermentans and S. mutans biofilms were grown in a 96-well active attachment model for 48 h. Several growth conditions were examined in the model, namely: S. oligofermentans was inoculated 24 h before S. mutans or vice versa; the growth medium was supplemented with 0.2% sucrose or 0.4% glucose; biofilms were grown under a constantly neutral pH or pH-cycling condition, which included 8 h of neutral pH and 16 h of pH 5.5. The 48-h biofilms were examined for viable cell counts and lactic acid and hydrogen peroxide production ability. When S. oligofermentans was inoculated first, it clearly inhibited the growth of S. mutans and reduced the biofilm lactic acid production by up to 8-fold through hydrogen peroxide production, independently of sugar supply and pH conditions. When S. mutans was inoculated first, the level of inhibition by S. oligofermentans varied depending on the sugar supply and pH conditions. Thus, the inhibition efficacy of S. oligofermentans against S. mutans in dual-species biofilms is influenced by environmental factors. This study provides practical information on how to maximize the efficacy of S. oligofermentans.

Growth and Inhibition of Microorganisms in the Presence of Sorbic Acid: A Review

1985 ◽  
Vol 48 (4) ◽  
pp. 364-375 ◽  
Author(s):  
MICHAEL B. LIEWEN ◽  
ELMER H. MARTH
Keyword(s):  
Environmental Factors ◽  
Water Activity ◽  
Sorbic Acid ◽  
Microbial Flora ◽  
Effective Inhibitor ◽  
Food Spoilage ◽  
Food Components ◽  
Common Causes ◽  
Activity Temperature ◽  
Antimicrobial Effectiveness

Sorbate (sorbic acid) generally is an effective inhibitor of most molds and yeasts and some bacteria. Environmental factors such as pH, water activity, temperature, atmosphere, microbial load, microbial flora and certain food components can influence the effectiveness of sorbate. Strains of microorganisms resistant to sorbate exist and therefore are common causes of food spoilage. Some molds and bacteria are able to degrade sorbate. This paper reviews the factors that affect the antimicrobial effectiveness of sorbate in foods.

A Bacteriological Study of Rampant Caries in Children

1987 ◽  
Vol 66 (1) ◽  
pp. 23-28 ◽  
Author(s):  
D. Boue ◽  
E. Armau ◽  
G. Tiraby
Keyword(s):  
Streptococcus Mutans ◽  
Dental Plaque ◽  
Extracellular Polysaccharide ◽  
Microbial Flora ◽  
Bacteriological Study ◽  
Selective Media ◽  
Microbiological Study ◽  
Pigmented Lesions ◽  
Caries Lesions ◽  
Rampant Caries

We undertook a microbiological study, in children, of dental plaque from sound surfaces or associated with rampant caries, both black-colored and unstained. Improved selective media allowed for the enumeration of bacteria belonging to specific genera or species present in plaque samples. A nearly similar bacterial distribution was found in both types of rampant caries. Aciduric flora, Streptococcus mutans, Veillonella, and Lactobacillus predominated in plaque over the lesions, whereas extracellular polysaccharide-producing streptococci other than S. mutans, as well as Actinomyces, were more abundant in plaque from sound surfaces. However, more lactobacilli and Actinomyces were recovered from pigmented lesions than from the unstained ones. These findings suggest that the microbial flora associated with black-pigmented lesions did not strongly differ from that observed over unstained caries lesions.

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