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Free Radical Biology & Medicine May 2018Nitric oxide (NO) can be generated endogenously via NO synthases or via the diet following the action of symbiotic nitrate-reducing bacteria in the oral cavity. Given...
Nitric oxide (NO) can be generated endogenously via NO synthases or via the diet following the action of symbiotic nitrate-reducing bacteria in the oral cavity. Given the important role of NO in smooth muscle control there is an intriguing suggestion that cardiovascular homeostasis may be intertwined with the presence of these bacteria. Here, we measured the abundance of nitrate-reducing bacteria in the oral cavity of 25 healthy humans using 16S rRNA sequencing and observed, for 3.5 h, the physiological responses to dietary nitrate ingestion via measurement of blood pressure, and salivary and plasma NO metabolites. We identified 7 species of bacteria previously known to contribute to nitrate-reduction, the most prevalent of which were Prevotella melaninogenica and Veillonella dispar. Following dietary nitrate supplementation, blood pressure was reduced and salivary and plasma nitrate and nitrite increased substantially. We found that the abundance of nitrate-reducing bacteria was associated with the generation of salivary nitrite but not with any other measured variable. To examine the impact of bacterial abundance on pharmacokinetics we also categorised our participants into two groups; those with a higher abundance of nitrate reducing bacteria (> 50%), and those with a lower abundance (< 50%). Salivary nitrite production was lower in participants with lower abundance of bacteria and these individuals also exhibited slower salivary nitrite pharmacokinetics. We therefore show that the rate of nitrate to nitrite reduction in the oral cavity is associated with the abundance of nitrate-reducing bacteria. Nevertheless, higher abundance of these bacteria did not result in an exaggerated plasma nitrite response, the best known marker of NO bioavailability. These data from healthy young adults suggest that the abundance of oral nitrate-reducing bacteria does not influence the generation of NO through the diet, at least when the host has a functional minimum threshold of these microorganisms.
Topics: Adult; Bacteria; Cross-Sectional Studies; Female; Humans; Male; Microbiota; Mouth; Nitrates; Nitric Oxide; Nitrites; Saliva
PubMed: 29550328
DOI: 10.1016/j.freeradbiomed.2018.03.023 -
Digestive and Liver Disease : Official... May 2019Growing evidence supports the potential role of intestinal microbiota in the pathophysiology of inflammatory bowel diseases (IBD) even if the literature does not reveal...
BACKGROUND
Growing evidence supports the potential role of intestinal microbiota in the pathophysiology of inflammatory bowel diseases (IBD) even if the literature does not reveal uniform alterations. The aim of the study was to evaluate the mucosal (MM) and faecal microbiota (FM) composition in a cohort of IBD patients compared to healthy controls (CTRLs).
METHODS
Faecal and mucosal samples were collected from 14 IBD patients and 11 CTRLs. The V1-V3 region of 16S rRNA locus was amplified on a 454-Junior Genome Sequencer. Reads were grouped into operational taxonomic units (OTUs) at a sequence similarity level of 97% for taxonomic assignment, and aligned for OTUs matching against Greengenes database.
RESULTS
Irrespective of disease localization and activity, in the MM of IBD patients a statistically significant increase of Proteobacteria (especially Enterobacteriaceae, Acidaminococcus, Veillonella dispar) and decrease of Firmicutes (especially Roseburia and Faecalibacterium prausnitzii) and Actinobacteria was found compared to CTRLs. In the colon district some specific bacterial biomarkers were identified: Enterobacteriaceae for IBD stools, Bacteroides for IBD biopsies, Mogibacteriaceae, Ruminococcaceae and Prevotella for CTRL stools, Ruminococcaceae for CTRL biopsies.
CONCLUSIONS
The profiles of FM were more similar to CTRLs, suggesting that microbiota adhering to the gut mucosa better discriminates patients from controls, with the identification of some interesting biomarkers.
Topics: Bacteria; Case-Control Studies; Colon; Feces; Female; Gastrointestinal Microbiome; Humans; Inflammatory Bowel Diseases; Intestinal Mucosa; Male; Middle Aged; RNA, Ribosomal, 16S
PubMed: 30573380
DOI: 10.1016/j.dld.2018.11.021 -
Molecular Oral Microbiology Jun 2018Bacteria residing in oral biofilms live in a state of dynamic equilibrium with one another. The intricate synergistic or antagonistic interactions between them are...
Bacteria residing in oral biofilms live in a state of dynamic equilibrium with one another. The intricate synergistic or antagonistic interactions between them are crucial for determining this balance. Using the six-species Zürich "supragingival" biofilm model, this study aimed to investigate interactions regarding growth and localization of the constituent species. As control, an inoculum containing all six strains was used, whereas in each of the further five inocula one of the bacterial species was alternately absent, and in the last, both streptococci were absent. Biofilms were grown anaerobically on hydroxyapatite disks, and after 64 h they were harvested and quantified by culture analyses. For visualization, fluorescence in situ hybridization and confocal laser scanning microscopy were used. Compared with the control, no statistically significant difference of total colony-forming units was observed in the absence of any of the biofilm species, except for Fusobacterium nucleatum, whose absence caused a significant decrease in total bacterial numbers. Absence of Streptococcus oralis resulted in a significant decrease in Actinomyces oris, and increase in Streptococcus mutans (P < .001). Absence of A. oris, Veillonella dispar or S. mutans did not cause any changes. The structure of the biofilm with regards to the localization of the species did not result in observable changes. In summary, the most striking observation of the present study was that absence of S. oralis resulted in limited growth of commensal A. oris and overgrowth of S. mutans. These data establish highlight S. oralis as commensal keeper of homeostasis in the biofilm by antagonizing S. mutans, so preventing a caries-favoring dysbiotic state.
Topics: Actinomyces; Biofilms; Colony Count, Microbial; Durapatite; Fusobacterium nucleatum; Homeostasis; In Situ Hybridization, Fluorescence; Microbial Consortia; Microbial Interactions; Microscopy, Confocal; Streptococcus mutans; Streptococcus oralis; Veillonella
PubMed: 29327482
DOI: 10.1111/omi.12216 -
Applied and Environmental Microbiology Dec 2015Around a third of oral bacteria cannot be grown using conventional bacteriological culture media. Community profiling targeting 16S rRNA and shotgun metagenomics methods...
Around a third of oral bacteria cannot be grown using conventional bacteriological culture media. Community profiling targeting 16S rRNA and shotgun metagenomics methods have proved valuable in revealing the complexity of the oral bacterial community. Studies investigating the role of oral bacteria in health and disease require phenotypic characterizations that are possible only with live cultures. The aim of this study was to develop novel culture media and use an in vitro biofilm model to culture previously uncultured oral bacteria. Subgingival plaque samples collected from subjects with periodontitis were cultured on complex mucin-containing agar plates supplemented with proteose peptone (PPA), beef extract (BEA), or Gelysate (GA) as well as on fastidious anaerobe agar plus 5% horse blood (FAA). In vitro biofilms inoculated with the subgingival plaque samples and proteose peptone broth (PPB) as the growth medium were established using the Calgary biofilm device. Specific PCR primers were designed and validated for the previously uncultivated oral taxa Bacteroidetes bacteria HOT 365 and HOT 281, Lachnospiraceae bacteria HOT 100 and HOT 500, and Clostridiales bacterium HOT 093. All agar media were able to support the growth of 10 reference strains of oral bacteria. One previously uncultivated phylotype, Actinomyces sp. HOT 525, was cultivated on FAA. Of 93 previously uncultivated phylotypes found in the inocula, 26 were detected in in vitro-cultivated biofilms. Lachnospiraceae bacterium HOT 500 was successfully cultured from biofilm material harvested from PPA plates in coculture with Parvimonas micra or Veillonella dispar/parvula after colony hybridization-directed enrichment. The establishment of in vitro biofilms from oral inocula enables the cultivation of previously uncultured oral bacteria and provides source material for isolation in coculture.
Topics: Actinomyces; Bacteriological Techniques; Bacteroidetes; Biofilms; Clostridiales; Culture Media; Dental Plaque; Humans; In Situ Hybridization, Fluorescence; Microbiota; Molecular Sequence Data; Mouth; Periodontitis; RNA, Ribosomal, 16S
PubMed: 26407883
DOI: 10.1128/AEM.02156-15 -
FEMS Immunology and Medical Microbiology Aug 2010We demonstrate that live donor Veillonella dispar cells can transfer the conjugative transposon Tn916 to four different Streptococcus spp. recipients in a multispecies...
We demonstrate that live donor Veillonella dispar cells can transfer the conjugative transposon Tn916 to four different Streptococcus spp. recipients in a multispecies oral consortium growing as a biofilm in a constant depth film fermentor. Additionally, we demonstrate that purified V. dispar DNA can transform Streptococcus mitis to tetracycline resistance in this experimental system. These data show that transfer of conjugative transposon-encoded antibiotic resistance can occur by transformation in addition to conjugation in biofilms.
Topics: Anti-Bacterial Agents; Biofilms; Conjugation, Genetic; DNA Transposable Elements; DNA, Bacterial; Drug Resistance, Bacterial; Humans; Streptococcus mitis; Transformation, Bacterial; Veillonella
PubMed: 20337719
DOI: 10.1111/j.1574-695X.2010.00661.x -
BMC Oral Health Jun 2021Supragingival plaque and saliva are commonly used for microbiome analysis. Many epidemiological studies have identified deciduous teeth caries as a risk factor for...
BACKGROUND
Supragingival plaque and saliva are commonly used for microbiome analysis. Many epidemiological studies have identified deciduous teeth caries as a risk factor for caries development in first permanent molar (FPM); nevertheless, to the best of our knowledge, there are no reports on the effects of deciduous teeth caries on the microbiome of healthy FPM. Additionally, it remains unclear whether saliva can be used instead of supragingival plaque for caries microbial studies. Therefore, we aimed to elucidate this issue, and to characterize and compare the oral microbiome of healthy FPMs in children with different caries statuses and that from children with and without caries in a similar microhabitat, by PacBio sequencing. Currently, few studies have investigated the oral microbiome of children using this technique.
METHODS
Thirty children (aged 7-9 years) with mixed dentition were enrolled; 15 had dental caries, and 15 did not. Supragingival plaques of deciduous molars and maxillary FPMs, and non-stimulating saliva samples were collected. DNA was extracted and the v1-v9 regions of 16S rRNA were amplified. Subsequently, PacBio sequencing and bioinformatic analyses were performed for microbiome identification.
RESULTS
The microbial alpha diversity of the saliva samples was lower than that of the supragingival plaque (p < 0.05); however, no differences were detected between deciduous teeth and FPMs (p > 0.05). In addition, the alpha and beta diversity of children with and without caries was also similar (p > 0.05). Nonmetric multidimensional scaling and Adonis analyses indicated that the microbial structure of salivary and supragingival plaque samples differ (p < 0.05). Further analysis of deciduous teeth plaque showed that Streptococcus mutans, Propionibacterium acidifaciens, and Veillonella dispar were more abundant in children with caries than in those without (p < 0.05); while in FPMs plaque, Selenomonas noxia was more abundant in healthy children (p < 0.05). No differences in microorganisms abundance were found in the saliva subgroups (p > 0.05).
CONCLUSION
We have determined that supragingival plaque was the best candidate for studying carious microbiome. Furthermore, S. mutans, V. dispar, and P. acidifaciens were highly associated with deciduous teeth caries. S. noxia may be associated with the abiding health of FPM; however, this requires additional studies.
Topics: Child; Cross-Sectional Studies; Dental Caries; Dental Caries Susceptibility; Dentition, Mixed; Humans; Microbiota; Propionibacterium; RNA, Ribosomal, 16S; Saliva; Selenomonas; Veillonella
PubMed: 34172026
DOI: 10.1186/s12903-021-01683-0 -
PeerJ 2017The study of ancient microorganisms in mineralized dental plaque or calculi is providing insights into microbial evolution, as well as lifestyles and disease states of...
BACKGROUND
The study of ancient microorganisms in mineralized dental plaque or calculi is providing insights into microbial evolution, as well as lifestyles and disease states of extinct cultures; yet, little is still known about the oral microbial community structure and function of pre-Columbian Caribbean cultures. In the present study, we investigated the dental calculi microbiome and predicted function of one of these cultures, known as the Saladoid. The Saladoids were horticulturalists that emphasized root-crop production. Fruits, as well as small marine and terrestrial animals were also part of the Saladoid diet.
METHODS
Dental calculi samples were recovered from the archaeological site of Sorcé, in the municipal island of Vieques, Puerto Rico, characterized using 16S rRNA gene high-throughput sequencing, and compared to the microbiome of previously characterized coprolites of the same culture, as well modern plaque, saliva and stool microbiomes available from the Human Microbiome Project.
RESULTS
Actinobacteria, Proteobacteria and Firmicutes comprised the majority of the Saladoid dental calculi microbiome. The Saladoid dental calculi microbiome was distinct when compared to those of modern saliva and dental plaque, but showed the presence of common inhabitants of modern oral cavities including sp., and . Cell motility, signal transduction and biosynthesis of other secondary metabolites may be unique features of the Saladoid microbiome.
DISCUSSION
Results suggest that the Saladoid dental calculi microbiome structure and function may possibly reflect a horticulturalist lifestyle and distinct dietary habits. Results also open the opportunity to further elucidate oral disease states in extinct Caribbean cultures and extinct indigenous cultures with similar lifestyles.
PubMed: 28480145
DOI: 10.7717/peerj.3277 -
International Dental Journal Mar 2024Psychological stress can be a common risk factor for the development of oral and systemic disease; therefore, analysis of a pathophysiologic mechanisms that may explain...
OBJECTIVE
Psychological stress can be a common risk factor for the development of oral and systemic disease; therefore, analysis of a pathophysiologic mechanisms that may explain this association may be significant in planning preventive strategies. The aim of this study was to investigate the association amongst academic stress, periodontal health, and salivary cortisol and nitrite and nitrate levels in a sample of university students.
METHODS
Participants (N = 14) were classified into 2 groups according to their exposure to academic stress due to periods of university exams (n = 6 and n = 8, respectively). All participants were subjected evlauted for their behavioural, psychological, and anthropometric parameters, as well as an oral health examination. A real-time polymerase chain reaction analysis in samples of saliva and plaque was used to detect Prevotella intermedia and Veillonella dispar as well as the total bacterial count. Nitrite/nitrate ratio (NR ratio) and cortisol in saliva were evaluated by enzyme-linked immunosorbent assay.
RESULTS
Full Mouth Bleeding Score, Full Mouth Plaque Score, and Gingival Index were significantly higher in the group exposed to academic stress. Nitrite was directly related to the presence of V dispar (coefficient, 0.13; P = .00; CI, 0.07 to 0.19) and inversely related to total bacterial count (coefficient, -0.07; P = .012; CI, -0.13 to 0.02). NR ratio was directly related to V dispar (coefficient, 4.35; P = .010; 95% CI, 1.35 to 7.36) and inversely related to total bacterial count (coefficient, -4.05; P = .018; 95% CI, -7.32 to 0.86).
CONCLUSIONS
These results confirm the importance of stress on periodontal health and salivary nitrite concentration and highlight a potential differential role of specific bacteria on nitrite concentration in saliva.
PubMed: 38538383
DOI: 10.1016/j.identj.2024.02.003 -
Archives of Microbiology May 2020The highest number (35.1% of global incident cases) of new oropharyngeal (OP) and hypopharyngeal (HP) cancer cases was reported in South-Central Asia. The highest... (Comparative Study)
Comparative Study
The highest number (35.1% of global incident cases) of new oropharyngeal (OP) and hypopharyngeal (HP) cancer cases was reported in South-Central Asia. The highest incidence of HP cancer in India was reported in East Khasi Hills District of Meghalaya, Aizawl District of Mizoram, and Kamrup Urban District of Assam. HP and OP cancer showed the highest mortality rate, worst prognoses and the highest rate of nodal metastases and distant metastases. Thus, research is required to detect specific biomarkers for early prevention and diagnosis for these cancers. Oral microbiome signatures in saliva are considered as a potential diagnostic biomarker for OP and HP cancer. Bacterial profile alterations in OP and HP cancer have not been reported in India population, to establish the association of oral bacteria in the progression of OP and HP cancer; we studied bacterial communities in saliva of eight OP and seven HP cancer patients as compared to healthy controls using 16S rRNA V3-V4 region sequencing. The higher abundance of Haemophilus parainfluenzae, Haemophilus influenzae and Prevotella copri and lower abundance of Rothia mucilaginosa, Aggregatibacter segnis, Veillonella dispar, Prevotella nanceiensis, Rothia aeria, Capnocytophaga ochracea, Neisseria bacilliformis, Prevotella nigrescens and Selenomonas noxia in saliva of OP and HP cancer patients may be considered as a non-invasive diagnostic biomarker for OP and HP cancer patients. Streptococcus anginosus may be considered as a non-invasive diagnostic biomarker for OP cancer patients only. Therefore, evaluation of salivary microbial biomarkers may be informative to understand the pathobiology and carcinogenesis of OP and HP cancer.
Topics: Bacteria; Biodiversity; Carcinoma, Squamous Cell; Case-Control Studies; Female; Humans; Hypopharyngeal Neoplasms; India; Male; Microbiota; Oropharyngeal Neoplasms; RNA, Ribosomal, 16S; Saliva
PubMed: 31832691
DOI: 10.1007/s00203-019-01790-1 -
Frontiers in Microbiology 2021Information on the time when a stain was deposited at a crime scene can be valuable in forensic investigations. It can link a DNA-identified stain donor with a crime or...
Information on the time when a stain was deposited at a crime scene can be valuable in forensic investigations. It can link a DNA-identified stain donor with a crime or provide a post-mortem interval estimation in cases with cadavers. The available methods for estimating stain deposition time have limitations of different types and magnitudes. In this proof-of-principle study we investigated for the first time the use of microbial DNA for this purpose in human saliva stains. First, we identified the most abundant and frequent bacterial species in saliva using publicly available 16S rRNA gene next generation sequencing (NGS) data from 1,848 samples. Next, we assessed time-dependent changes in 15 identified species using de-novo 16S rRNA gene NGS in the saliva stains of two individuals exposed to indoor conditions for up to 1 year. We selected four bacterial species, i.e., , and showing significant time-dependent changes and developed a 4-plex qPCR assay for their targeted analysis. Then, we analyzed the saliva stains of 15 individuals exposed to indoor conditions for up to 1 month. Bacterial counts generally increased with time and explained 54.9% of the variation ( = <2.2E-16). Time since deposition explained ≥86.5% and ≥88.9% of the variation in each individual and species, respectively ( = <2.2E-16). Finally, based on sample duplicates we built and tested multiple linear regression models for predicting the stain deposition time at an individual level, resulting in an average mean absolute error (MAE) of 5 days (ranging 3.3-7.8 days). Overall, the deposition time of 181 (81.5%) stains was correctly predicted within 1 week. Prediction models were also assessed in stains exposed to similar conditions up to 1 month 7 months later, resulting in an average MAE of 8.8 days (ranging 3.9-16.9 days). Our proof-of-principle study suggests the potential of the DNA profiling of human commensal bacteria as a method of estimating saliva stains time since deposition in the forensic scenario, which may be expanded to other forensically relevant tissues. The study considers practical applications of this novel approach, but various forensic developmental validation and implementation criteria will need to be met in more dedicated studies in the future.
PubMed: 34149638
DOI: 10.3389/fmicb.2021.647933