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Journal of Bacteriology Dec 2000Dental plaque is a complex biofilm that accretes in a series of discrete steps proceeding from a gram-positive streptococcus-rich biofilm to a structure rich in...
Dental plaque is a complex biofilm that accretes in a series of discrete steps proceeding from a gram-positive streptococcus-rich biofilm to a structure rich in gram-negative anaerobes. This study investigated information flow between two unrelated plaque bacteria, Streptococcus cristatus and Porphyromonas gingivalis. A surface protein of S. cristatus caused repression of the P. gingivalis fimbrial gene (fimA), as determined by a chromosomal fimA promoter-lacZ reporter construct and by reverse transcription-PCR. Signaling activity was associated with a 59-kDa surface protein of S. cristatus and showed specificity for the fimA gene. Furthermore, P. gingivalis was unable to form biofilm microcolonies with S. cristatus. Thus, S. cristatus is capable of modulating virulence gene expression in P. gingivalis, consequently influencing the development of pathogenic plaque.
Topics: Antibiosis; Bacterial Proteins; Bacteroidaceae Infections; Biofilms; Dental Plaque; Fimbriae Proteins; Gene Expression Regulation, Bacterial; Porphyromonas gingivalis; Signal Transduction; Streptococcus; Virulence
PubMed: 11092870
DOI: 10.1128/JB.182.24.7067-7069.2000 -
FEMS Microbiology Letters Sep 2006The Mfa1 protein of Porphyromonas gingivalis is the structural subunit of the short fimbriae and mediates coadhesion between P. gingivalis and Streptococcus gordonii. We...
The Mfa1 protein of Porphyromonas gingivalis is the structural subunit of the short fimbriae and mediates coadhesion between P. gingivalis and Streptococcus gordonii. We utilized a promoter-lacZ reporter construct to examine the regulation of mfa1 expression in consortia with common oral plaque bacteria. Promoter activity of mfa1 was inhibited by S. gordonii, Streptococcus sanguinis and Streptococcus mitis. In contrast, Streptococcus mutans, Streptococcus cristatus, Actinomyces naeslundii, Actinobacillus actinomycetemcomitans and Fusobacterium nucleatum did not affect mfa1 expression. Expression of SspA/B, the streptococcal receptor for Mfa1, was not required for regulation of mfa1 promoter activity. Proteinaceous molecule(s) in oral streptococci may be responsible for regulation of Mfa1 expression. Porphyromonas gingivalis is capable of detecting heterologous organisms, and responds to selected organisms by specific gene regulation.
Topics: Actinomyces; Adhesins, Bacterial; Aggregatibacter actinomycetemcomitans; Artificial Gene Fusion; Bacterial Adhesion; Base Sequence; Fimbriae Proteins; Fusobacterium nucleatum; Gene Expression Regulation, Bacterial; Genes, Reporter; Lac Operon; Molecular Sequence Data; Porphyromonas gingivalis; Promoter Regions, Genetic; Streptococcus; Transcription Initiation Site; beta-Galactosidase
PubMed: 16907740
DOI: 10.1111/j.1574-6968.2006.00357.x -
Applied and Environmental Microbiology Jun 2020The human oral cavity is a complex ecosystem, and the alterations in salivary microbial communities are associated with both oral and nonoral diseases. The Mediterranean...
The human oral cavity is a complex ecosystem, and the alterations in salivary microbial communities are associated with both oral and nonoral diseases. The Mediterranean diet (MD) is a healthy dietary pattern useful for both prevention and treatment of several diseases. To further explore the effects of the MD on human health, in this study, we investigated the changes in the salivary microbial communities in overweight/obese subjects after an individually tailored MD-based nutritional intervention. Healthy overweight and obese subjects were randomized between two intervention groups. The MD group (Med-D group) increased their MD adherence during 8 weeks of intervention while the control diet (control-D) group did not change their dietary habits. The salivary microbiota was assessed at baseline and after 4 and 8 weeks of intervention. Despite no observed changes in the overall salivary microbiota composition, we found a significant decrease in the relative abundances of species-level operational taxonomic units annotated as , , and in the Med-D group compared to that in the control-D group after 8 weeks of intervention, which are known to be associated with periodontal disease. Such variations were significantly linked to dietary variables such as MD adherence rates and intakes of animal versus vegetable proteins. In addition, increased levels of were observed in the Med-D group, which has been reported as an antagonistic taxon inhibiting gene expression. Our findings suggest that an MD-based nutritional intervention may be implicated in reducing periodontal bacteria, and an MD may be a dietary strategy supportive of oral homeostasis. Changes in dietary behavior with increased adherence to a Mediterranean diet can determine a reduction of periodontopathogenic bacterial abundances in the saliva of overweight subjects with cardiometabolic risk due to an unhealthy lifestyle, without any change in individual energy intake, nutrient intake, and physical activity.
Topics: Adult; Bacterial Physiological Phenomena; Diet, Mediterranean; Female; Humans; Male; Middle Aged; Obesity; Overweight; Periodontal Diseases; Random Allocation; Saliva; Young Adult
PubMed: 32276980
DOI: 10.1128/AEM.00777-20 -
The Journal of Antimicrobial... Sep 2009Although long-term use of azithromycin has shown a significant clinical improvement for patients with cystic fibrosis (CF), its long-term effect on the susceptibility of...
Molecular characterization of macrolide resistance determinants [erm(B) and mef(A)] in Streptococcus pneumoniae and viridans group streptococci (VGS) isolated from adult patients with cystic fibrosis (CF).
OBJECTIVES
Although long-term use of azithromycin has shown a significant clinical improvement for patients with cystic fibrosis (CF), its long-term effect on the susceptibility of commensal flora within CF airways has not yet been examined. We therefore suggest that long-term use of azithromycin increases macrolide resistance in commensal streptococci.
METHODS
Erythromycin susceptibility in naturally colonizing viridans group streptococci (VGS) was characterized, as well as macrolide resistance gene determinants through sequence analysis, in pneumococci (n = 15) and VGS [n = 84; i.e. Streptococcus salivarius (n = 30), Streptococcus mitis (n = 17), Streptococcus sanguinis (n = 11), Streptococcus oralis (n = 10), Streptococcus parasanguinis (n = 6), Streptococcus gordonii (n = 3), Streptococcus infantis (n = 3), Streptococcus cristatus (n = 2), Streptococcus anginosus (n = 1) and Streptococcus australis (n = 1)] isolated from sputum from 24 adult CF patients, who were on oral azithromycin therapy for at least the previous 7 months.
RESULTS
Almost three-quarters of isolates (74; 74.7%) were resistant to erythromycin, whilst a further 15 (15.2%) had reduced susceptibility, leaving only 10 (10.1%) isolates susceptible to erythromycin. The majority (89.8%) were not susceptible to erythromycin, as demonstrated by possession of the erm(B) gene in 25/99 (25.3%), the mef(A) gene in 1/99 (1.0%), the mef(E) gene in 75/99 (75.8%) and both erm(B) and mef(E) genes simultaneously in 11/99 (11.1%). These results indicate that genotypic resistance for macrolides is common in VGS in adult CF patients, with efflux being over three times more frequent.
CONCLUSIONS
Long-term treatment with azithromycin in CF patients may reduce antibiotic susceptibility in commensal VGS, where these organisms may potentially act as a reservoir of macrolide resistance determinants for newly acquired and antibiotic-susceptible pathogens.
Topics: Adult; Anti-Bacterial Agents; Azithromycin; Bacterial Proteins; Cystic Fibrosis; DNA, Bacterial; Drug Resistance, Bacterial; Erythromycin; Humans; Macrolides; Membrane Proteins; Methyltransferases; Microbial Sensitivity Tests; Molecular Sequence Data; Sequence Analysis, DNA; Streptococcal Infections; Streptococcus
PubMed: 19584106
DOI: 10.1093/jac/dkp213 -
Journal of Investigative and Clinical... Aug 2012Previous work has indicated that environmental stresses on bacteria might lead to an upregulation of stress response. LED curing lights (315-400 nm) and other UV lights...
UV-C-irradiation sublethal stress does not alter antibiotic susceptibility of the viridans group streptococci to β-lactam, macrolide, and fluoroquinolone antibiotic agents.
AIM
Previous work has indicated that environmental stresses on bacteria might lead to an upregulation of stress response. LED curing lights (315-400 nm) and other UV lights used in tooth whitening cosmetic procedures might act as stresses. We examined the effect of UV-C light, as a high-energy surrogate to the lower-energy UV-A light used in such instruments, to examine its effect on the antibiotic susceptibility of viridans group streptococci.
METHODS
Twelve species of viridans group streptococci were examined in this study: Streptococcus anginosus, Streptococcus australis, Streptococcus cristatus, Streptococcus gordonii, Streptococcus infantis, Streptococcus mitis, Streptococcus mutans, Streptococcus oralis, Streptococcus parasanguinis, Streptococcus pneumoniae, Streptococcus salivarius, and Streptococcus sanguinis. These organisms were exposed to varying degrees of sublethal UV-C radiation, and their minimum inhibitory concentration susceptibility was determined by broth dilution assay against three classes of commonly-used antibiotics: β-lactams (penicillin), macrolides (erythromycin), and fluoroquinolones (ciprofloxacin).
RESULTS
There was no significant difference between antibiotic susceptibility before UV-C exposure and following maximum sublethal stress, prior to cell death due to fatal UV-C exposure.
CONCLUSIONS
Exposure to UV-C light will not result in altered antibiotic susceptibility patterns on viridans group streptococci. Given that UV-C is more toxic and mutagenic than UV-A light, it is unlikely than UV-A light would yield any difference in response to such exposure.
Topics: Anti-Bacterial Agents; Ciprofloxacin; Drug Resistance, Bacterial; Erythromycin; Microbial Sensitivity Tests; Penicillins; Ultraviolet Rays; Viridans Streptococci
PubMed: 22887906
DOI: 10.1111/j.2041-1626.2011.00100.x -
Journal of Clinical Microbiology Nov 2010Previous studies have confirmed the association of the acid producers Streptococcus mutans and Lactobacillus spp. with childhood caries, but they also suggested these...
Previous studies have confirmed the association of the acid producers Streptococcus mutans and Lactobacillus spp. with childhood caries, but they also suggested these microorganisms are not sufficient to explain all cases of caries. In addition, health-associated bacterial community profiles are not well understood, including the importance of base production and acid catabolism in pH homeostasis. The bacterial community composition in health and in severe caries of the young permanent dentition was compared using Sanger sequencing of the ribosomal 16S rRNA genes. Lactobacillus species were dominant in severe caries, and levels rose significantly as caries progressed from initial to deep lesions. S. mutans was often observed at high levels in the early stages of caries but also in some healthy subjects and was not statistically significantly associated with caries progression in the overall model. Lactobacillus or S. mutans was found either at low levels or not present in several samples. Other potential acid producers observed at high levels in these subjects included strains of Selenomonas, Neisseria, and Streptococcus mitis. Propionibacterium FMA5 was significantly associated with caries progression but was not found at high levels. An overall loss of community diversity occurred as caries progressed, and species that significantly decreased included the Streptococcus mitis-S. pneumoniae-S. infantis group, Corynebacterium matruchotii, Streptococcus gordonii, Streptococcus cristatus, Capnocytophaga gingivalis, Eubacterium IR009, Campylobacter rectus, and Lachnospiraceae sp. C1. The relationship of acid-base metabolism to 16S rRNA gene-based species assignments appears to be complex, and metagenomic approaches that would allow functional profiling of entire genomes will be helpful in elucidating the microbial pathogenesis of caries.
Topics: Adolescent; Bacteria; Biodiversity; Carboxylic Acids; Child; Cluster Analysis; DNA, Bacterial; DNA, Ribosomal; Dental Caries; Female; Humans; Male; Metagenome; Phylogeny; RNA, Ribosomal, 16S; Sequence Analysis, DNA; Tooth
PubMed: 20826648
DOI: 10.1128/JCM.01232-10 -
Journal of Clinical Microbiology Jun 2008Culture-based studies have shown that Streptococcus mutans and lactobacilli are associated with root caries (RC). The purpose of the present study was to assess the...
Culture-based studies have shown that Streptococcus mutans and lactobacilli are associated with root caries (RC). The purpose of the present study was to assess the bacterial diversity of RC in elderly patients by use of culture-independent molecular techniques and to determine the associations of specific bacterial species or bacterial communities with healthy and carious roots. Plaque was collected from root surfaces of 10 control subjects with no RC and from 11 subjects with RC. The bacterial 16S rRNA genes from extracted DNA were PCR amplified, cloned, and sequenced to determine species identity. From a total of 3,544 clones, 245 predominant species or phylotypes were observed, representing eight bacterial phyla. The majority (54%) of the species detected have not yet been cultivated. Species of Selenomonas and Veillonella were common in all samples. The healthy microbiota included Fusobacterium nucleatum subsp. polymorphum, Leptotrichia spp., Selenomonas noxia, Streptococcus cristatus, and Kingella oralis. Lactobacilli were absent, S. mutans was present in one, and Actinomyces spp. were present in 50% of the controls. In contrast, the microbiota of the RC subjects was dominated by Actinomyces spp., lactobacilli, S. mutans, Enterococcus faecalis, Selenomonas sp. clone CS002, Atopobium and Olsenella spp., Prevotella multisaccharivorax, Pseudoramibacter alactolyticus, and Propionibacterium sp. strain FMA5. The bacterial profiles of RC showed considerable subject-to-subject variation, indicating that the microbial communities are more complex than previously presumed. The data suggest that putative etiological agents of RC include not only S. mutans, lactobacilli, and Actinomyces but also species of Atopobium, Olsenella, Pseudoramibacter, Propionibacterium, and Selenomonas.
Topics: Aged, 80 and over; DNA, Bacterial; DNA, Ribosomal; Dental Plaque; Female; Genes, rRNA; Gram-Negative Bacteria; Gram-Negative Bacterial Infections; Gram-Positive Bacteria; Gram-Positive Bacterial Infections; Humans; Male; Polymerase Chain Reaction; RNA, Ribosomal, 16S; Root Caries; Sequence Analysis, DNA
PubMed: 18385433
DOI: 10.1128/JCM.02411-07 -
Microbiology (Reading, England) Oct 2007The development of complex multispecies communities such as biofilms is controlled by interbacterial communication systems. We have previously reported an intergeneric...
The development of complex multispecies communities such as biofilms is controlled by interbacterial communication systems. We have previously reported an intergeneric communication between two oral bacteria, Streptococcus cristatus and Porphyromonas gingivalis, that results in inhibition of fimA expression. Here, we demonstrate that a surface protein, arginine deiminase (ArcA), of S. cristatus serves as a signal that initiates intergeneric communication. An ArcA-deficient mutant of S. cristatus is unable to communicate with P. gingivalis. Furthermore, arginase activity is not essential for the communication, and ArcA retains the ability to repress expression of fimA in the presence of arginine deiminase inhibitors. These results present a novel mechanism by which intergeneric communication in dental biofilms is accomplished.
Topics: Artificial Gene Fusion; Bacterial Proteins; DNA, Bacterial; Down-Regulation; Fimbriae Proteins; Gene Deletion; Genes, Reporter; Hydrolases; Molecular Sequence Data; Mutagenesis, Insertional; Porphyromonas gingivalis; Quorum Sensing; Sequence Analysis, DNA; Signal Transduction; Streptococcus; beta-Galactosidase
PubMed: 17906122
DOI: 10.1099/mic.0.2007/009050-0 -
ACS Synthetic Biology Sep 20202,5-Dimethylpyrazine (2,5-DMP) is an indispensable additive for flavoring in the food industry and an important substrate for producing hypoglycemic and antilipolytic...
2,5-Dimethylpyrazine (2,5-DMP) is an indispensable additive for flavoring in the food industry and an important substrate for producing hypoglycemic and antilipolytic drugs. However, 2,5-DMP is produced by chemical synthesis in industry. Herein, a "green" strategy to produce 2,5-DMP has been reported for the first time. To do this, we rewrote the 2,5-DMP biosynthesis pathway and substrate transmembrane transport in an l-threonine high-yielding strain to promote highly efficient 2,5-DMP production from glucose by submerged fermentation. The final strain T6-47-7 could produce 1.43 ± 0.07 g/L of 2,5-DMP with a carbon yield of 6.78% and productivity of 0.715 g/(L·d) in shake-flask fermentation using a phase-wise manner of hypoxia-inducible expression. The design-based strategy for constructing the 2,5-DMP high-yielding strain reported here could serve as a general concept for breeding high-yielding strains that produce some other type of alkylpyrazine.
Topics: Alcohol Oxidoreductases; Biosynthetic Pathways; Escherichia coli; Glucose; Metabolic Engineering; NAD; Oxidoreductases Acting on CH-NH Group Donors; Phylogeny; Pyrazines; Streptococcus; Polyamine Oxidase
PubMed: 32841563
DOI: 10.1021/acssynbio.0c00329 -
Biotechnology For Biofuels and... Mar 20242,5-Dimethylpyrazine (2,5-DMP) is important pharmaceutical raw material and food flavoring agent. Recently, engineering microbes to produce 2,5-DMP has become an...
2,5-Dimethylpyrazine (2,5-DMP) is important pharmaceutical raw material and food flavoring agent. Recently, engineering microbes to produce 2,5-DMP has become an attractive alternative to chemical synthesis approach. In this study, metabolic engineering strategies were used to optimize the modified Escherichia coli BL21 (DE3) strain for efficient synthesis of 2,5-DMP using L-threonine dehydrogenase (EcTDH) from Escherichia coli BL21, NADH oxidase (EhNOX) from Enterococcus hirae, aminoacetone oxidase (ScAAO) from Streptococcus cristatus and L-threonine transporter protein (EcSstT) from Escherichia coli BL21, respectively. We further optimized the reaction conditions for synthesizing 2,5-DMP. In optimized conditions, the modified strain can convert L-threonine to obtain 2,5-DMP with a yield of 2897.30 mg/L. Therefore, the strategies used in this study contribute to the development of high-level cell factories for 2,5-DMP.
PubMed: 38500189
DOI: 10.1186/s13068-024-02487-4