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Journal of Dental Research Jun 1987Under anaerobic conditions, the rate of metabolism of lactate by starved resting cells of Veillonella dispar ATCC 17745 was very low. Because pyruvate was metabolized...
Under anaerobic conditions, the rate of metabolism of lactate by starved resting cells of Veillonella dispar ATCC 17745 was very low. Because pyruvate was metabolized well by the starved cells, oxidation of lactate to pyruvate, which is the first step of the lactate metabolism, must have been limited in the cells. In the starved cells, the levels of the metabolic intermediates, oxalacetate or fumarate, of which reductions to malate or to succinate could be coupled with lactate oxidation to pyruvate and initiate lactate metabolism, were quite low, suggesting that these had been reduced during the starvation steps under strictly anaerobic conditions. Thus, the starved cells were unable to start the anaerobic lactate metabolism because of shortage of such reducible substrates. L-serine greatly enhanced anaerobic lactate metabolism of the starved cells. This enhancement may have been due to metabolism of L-serine itself and conversion to oxalacetate and fumarate, which made it possible to begin lactate oxidation.
Topics: Amino Acids; Anaerobiosis; Aspartate Ammonia-Lyase; Cell-Free System; L-Serine Dehydratase; Lactates; Serine; Stimulation, Chemical; Veillonella
PubMed: 3114345
DOI: 10.1177/00220345870660061401 -
Bioengineering (Basel, Switzerland) Oct 2022Bacterial adhesion to dental implants is the onset for the development of pathological biofilms. Reliable characterization of this initial process is the basis towards...
Bacterial adhesion to dental implants is the onset for the development of pathological biofilms. Reliable characterization of this initial process is the basis towards the development of anti-biofilm strategies. In the present study, single-cell force spectroscopy (SCFS), by means of an atomic force microscope connected to a microfluidic pressure control system (FluidFM), was used to comparably measure adhesion forces of different oral bacteria within a similar experimental setup to the common implant material titanium. The bacteria selected belong to different ecological niches in oral biofilms: the commensal pioneers and ; secondary colonizer ; and the late colonizing pathogens as well as fimbriated and non-fimbriated . The results showed highest values for early colonizing pioneer species, strengthening the link between adhesion forces and bacteria's role in oral biofilm development. Additionally, the correlation between biophysical cellular characteristics and SCFS results across species was analyzed. Here, distinct correlations between electrostatically driven maximum adhesion force, bacterial surface elasticity and surface charge as well as single-molecule attachment points, stretching capability and metabolic activity, could be identified. Therefore, this study provides a step towards the detailed understanding of oral bacteria initial adhesion and could support the development of infection-resistant implant materials in future.
PubMed: 36290534
DOI: 10.3390/bioengineering9100567 -
Journal of Dentistry Jan 2021Microbiota comparisons between healthy and diseased dental tissues have accentuated the importance of cultivating and identifying bacterial species that play a role in...
OBJECTIVE
Microbiota comparisons between healthy and diseased dental tissues have accentuated the importance of cultivating and identifying bacterial species that play a role in the initiation and progression of dental caries. The objective of this study was to evaluate the bacterial community composition in caries-active and caries-free children.
METHODS
Supragingival plaque samples were collected from 64 caries-active and 64 caries-free Middle Eastern children. The hypervariable V3-V4 of the bacterial 16S rRNA gene was sequenced with Human Oral Microbe Identification using Next Generation Sequencing. Microbial community structure and composition analyses were performed by processing operational taxonomic units. Bioinformatic analyses, including analysis of similarity, alpha and beta diversities, and principal coordinate analysis, were carried out.
RESULTS
Diversity indices did not find differences between the caries-active and caries-free groups (p > 0.05). Similarity analysis demonstrated that the microbiota composition did not differ between the two groups. Comparative analysis at the species level revealed a significantly higher relative abundance of Leptotrichia shahii, Prevotella melaninogenica, Veillonella dispar, Leptotrichia HOT 498, and Streptococcus mutans in caries-active children (p < 0.05). Corynebacterium matruchotii, Lautropia mirabilis, Neisseria elongata, and Corynebacterium durum were relatively more abundant in the caries-free group (p < 0.05). Species belonging to the Leptotrichia, Prevotella, and Veillonella genera were significantly predominant in the caries-active subjects.
CONCLUSION
In view of the lack of a clear association between Corynebacterium spp. and dental caries status in the literature, the predominance of these species in caries-free children warrants further research to understand their possible role in a health-associated microbial community.
CLINICAL SIGNIFICANCE
Understanding the relationship between specific bacteria present in dental biofilms and health and disease is essential for preventing and combating dental caries. Using advanced next generation sequencing techniques, the present study demonstrated the complexity of the caries microbiome and identified species/genera whose virulence or protective properties should be further explored.
Topics: Burkholderiaceae; Child; Corynebacterium; Dental Caries; Dental Caries Susceptibility; Dental Plaque; Dentition; Humans; Leptotrichia; Microbiota; RNA, Ribosomal, 16S; Veillonella
PubMed: 33248211
DOI: 10.1016/j.jdent.2020.103539 -
NPJ Biofilms and Microbiomes Mar 2020Cigarette smoking affects the oral microbiome, which is related to various systemic diseases. While studies that investigated the relationship between smoking and the...
Cigarette smoking affects the oral microbiome, which is related to various systemic diseases. While studies that investigated the relationship between smoking and the oral microbiome by 16S rRNA amplicon sequencing have been performed, investigations involving metagenomic sequences are rare. We investigated the bacterial species composition in the tongue microbiome, as well as single-nucleotide variant (SNV) profiles and gene content of these species, in never and current smokers by utilizing metagenomic sequences. Among 234 never smokers and 52 current smokers, beta diversity, as assessed by weighted UniFrac measure, differed between never and current smokers (pseudo-F = 8.44, R = 0.028, p = 0.001). Among the 26 species that had sufficient coverage, the SNV profiles of Actinomyces graevenitzii, Megasphaera micronuciformis, Rothia mucilaginosa, Veillonella dispar, and one Veillonella sp. were significantly different between never and current smokers. Analysis of gene and pathway content revealed that genes related to the lipopolysaccharide biosynthesis pathway in Veillonella dispar were present more frequently in current smokers. We found that species-level tongue microbiome differed between never and current smokers, and 5 species from never and current smokers likely harbor different strains, as suggested by the difference in SNV frequency.
Topics: Adult; Aged; Bacteria; Case-Control Studies; Cigarette Smoking; DNA, Bacterial; DNA, Ribosomal; Female; High-Throughput Nucleotide Sequencing; Humans; Male; Metagenomics; Middle Aged; Phylogeny; Polymorphism, Single Nucleotide; RNA, Ribosomal, 16S; Sequence Analysis, DNA; Tongue
PubMed: 32170059
DOI: 10.1038/s41522-020-0121-6 -
Nitric Oxide : Biology and Chemistry Jan 2021Nitric oxide (NO) produced in the oral cavity is a powerful resource for the human body, especially when NO-syntethase production is not adequate. The role of oral...
BACKGROUND
Nitric oxide (NO) produced in the oral cavity is a powerful resource for the human body, especially when NO-syntethase production is not adequate. The role of oral microbiome in determining blood pressure levels has been linked to the active role of some bacterial species involved in the nitro-reducing process. In the present study we investigated the correlation between selected oral microbiome characteristics, nitric oxide (NO) concentration in saliva and their association with hypertension.
METHODS
A case-control study including 48 (25 normotensive and 23 hypertensive subjects), subjects between 50 and 70 years old, was carried out at the dental clinic of an Italian teaching hospital. Characteristics of participants have been evaluated by means of a physical examination, and by an assisted interview. A real-time polymerase chain reaction in samples of saliva and plaque was used to detect Aggregatibacter actinomycetemcomitans, Prevotella intermedia, Tannerella forsythia, Porphyromonas gingivalis, Treponema denticola, Streptococcus mutans, Streptococcus sanguinis, Veillonella dispar and Neisseria subflava as well as total bacterial count. Nitric oxide in saliva was evaluated by the ELISA method.
RESULTS
Normotensive subjects, compared with hypertensive subjects, had significantly higher concentration of NO (165.77 ± 61.7 vs 57.49 ± 19.61 μmol/l; p = 0.023), and higher bacterial concentration of the supragingival plaque (4.73E+07 ± 4.33+07 vs 4.02E+07 ± 4.00+07; p = 0.024). Bacterial species, usually associated to good oral health status, such as Neisseria subflava, were significantly more present in normotensive subjects than in hypertensive ones (9090.88 ± 5481.49 vs 4791.35 ± 4349.37; p < 0.001). considering the concentration of bacteria as a biomarker of the development of hypertension.
CONCLUSIONS
The results support the association between hypertension, oral microbiome and salivary nitric oxide, in fact do the results allow us to establish any biomarkers (microbial or biochemical, NO) that allow early therapeutic intervention.
Topics: Aged; Bacteria; Bacterial Load; Case-Control Studies; Female; Humans; Hypertension; Male; Microbiota; Middle Aged; Mouth; Nitric Oxide; Saliva
PubMed: 33186726
DOI: 10.1016/j.niox.2020.11.002 -
Journal of Dental Research Jun 2020Severe early childhood caries (S-ECC) is a multifactorial disease that can lead to suffering and reduced oral health-related quality of life in young children. The...
Severe early childhood caries (S-ECC) is a multifactorial disease that can lead to suffering and reduced oral health-related quality of life in young children. The bacterial and fungal composition of dental plaque and how children's sex is associated with S-ECC are largely unknown. In this study, V4-16S rRNA and ITS1 rRNA gene amplicon sequencing was used to compare the plaque bacteriome and mycobiome of children <72 mo of age: 40 with S-ECC (15 males, 25 females) and 40 caries-free (19 males, 21 females). Health- and nutrition-related questionnaire data were also investigated. This study aimed to analyze potential sex-based differences in the supragingival plaque microbiota of young children with S-ECC and those caries-free. Behavioral and nutritional habit differences were observed between children with S-ECC and those caries-free and between male and female children. Overall, higher levels of , and other bacterial species were found in the S-ECC group as compared with caries-free controls ( < 0.05). A significant difference in the abundance of was observed between males and females with S-ECC ( < .05). Fungal taxonomic analysis showed significantly higher levels of in the plaque of children with S-ECC as compared with those caries-free ( < 0.05), but no differences were observed with ( > 0.05). Significant differences in the relative abundance of , and fungal species were also observed between the caries-free and S-ECC groups ( < 0.05). Machine learning analysis revealed the most important bacterial and fungal species for classifying S-ECC versus caries-free. Different patterns of crosstalk between microbial species were observed between male and female children. Our work demonstrates that plaque microbiota and sex may be important determinants for S-ECC and could be factors to consider for inclusion in caries risk assessment tools.
Topics: Candida; Child; Child, Preschool; Dental Caries; Dental Plaque; Female; Humans; Male; Microbiota; Quality of Life; RNA, Ribosomal, 16S; Streptococcus mutans; Veillonella
PubMed: 32109360
DOI: 10.1177/0022034520908595 -
PloS One 2017Poor oral hygiene often leads to chronic diseases such as periodontitis and dental caries resulting in substantial economic costs and diminished quality of life in not...
Poor oral hygiene often leads to chronic diseases such as periodontitis and dental caries resulting in substantial economic costs and diminished quality of life in not only adults but also in children. In this study, the salivary microbiome was characterized in a group of children stratified by the Simplified Oral Hygiene Index (OHI-S). Illumina MiSeq high-throughput sequencing based on the 16S rRNA was utilized to analyze 90 salivary samples (24 Good, 31 Moderate and 35 Poor oral hygiene) from a cohort of Thai children. A total of 38,521 OTUs (Operational Taxonomic Units) with a 97% similarity were characterized in all of the salivary samples. Twenty taxonomic groups (Seventeen genera, two families and one class; Streptococcus, Veillonella, Gemellaceae, Prevotella, Rothia, Porphyromonas, Granulicatella, Actinomyces, TM-7-3, Leptotrichia, Haemophilus, Selenomonas, Neisseria, Megasphaera, Capnocytophaga, Oribacterium, Abiotrophia, Lachnospiraceae, Peptostreptococcus, and Atopobium) were found in all subjects and constituted 94.5-96.5% of the microbiome. Of these twenty genera, the proportion of Streptococcus decreased while Veillonella increased with poor oral hygiene status (P < 0.05). Furthermore, an unassigned species of Veillonella, Veillonella dispar and Veillonella parvula tended to be elevated in the Poor oral hygiene group. This is the first study demonstrating an important association between increase of Veillonella and poor oral hygiene status in children. However, further studies are required to identify the majority of Veillonella at species level in salivary microbiome of the Poor oral hygiene group.
Topics: Adolescent; Child; Female; Humans; Male; Microbiota; Oral Hygiene Index; RNA, Bacterial; RNA, Ribosomal, 16S; Saliva
PubMed: 28934367
DOI: 10.1371/journal.pone.0185274 -
Frontiers in Microbiology 2022This study analyzed the antimicrobial and antibiofilm action and cytotoxicity of extract (HEScL) and silver nanoparticles (AgNPs-HEScL) from leaves. GC-MS, UV-Vis, EDX,...
This study analyzed the antimicrobial and antibiofilm action and cytotoxicity of extract (HEScL) and silver nanoparticles (AgNPs-HEScL) from leaves. GC-MS, UV-Vis, EDX, FEG/SEM, DLS and zeta potential assays were used to characterize the extract or nanoparticles. Antimicrobial, antibiofilm and cytotoxicity analyses were carried out by methods: agar diffusion, microdilution and normal oral keratinocytes spontaneously immortalized (NOK-SI) cell culture. MICs of planktonic cells ranged from 31.2-250 (AgNPs-HEScL) to 1,296.8-10,375 μg/ml (HEScL) for , , , , , , , and . AgNPs-HEScL showed antibiofilm effects (125-8,000 μg/ml) toward , and , and and . The NOK-SI exhibited no cytotoxicity when treated with 32.8 and 680.3 μg/ml of AgNPs-HEScL and HEScL, respectively, for 5 min. The data suggest potential antimicrobial and antibiofilm action of HEScL, and more specifically, AgNPs-HEScL, involving pathogens of medical and dental interest (dose-, time- and species-dependent). The cytotoxicity of HEScL and AgNPs-HEScL detected in NOK-SI was dose- and time-dependent. This study presents toxicological information about the lyophilized ethanolic extract of leaves, including their metallic nanoparticles, and adds scientific values to incipient studies found in the literature.
PubMed: 36246249
DOI: 10.3389/fmicb.2022.995521 -
Relationship of the lung microbiome with PD-L1 expression and immunotherapy response in lung cancer.Respiratory Research Dec 2021Lung cancer is the primary cause of cancer-related deaths worldwide. The human lung serves as a niche to a unique and dynamic bacterial community that is related to the...
BACKGROUND
Lung cancer is the primary cause of cancer-related deaths worldwide. The human lung serves as a niche to a unique and dynamic bacterial community that is related to the development of multiple diseases. Here, we investigated the differences in the lung microbiomes of patients with lung cancer.
METHODS
16S rRNA sequencing was performed to evaluate the respiratory tract microbiome present in the bronchoalveolar lavage fluid. Patients were stratified based on programmed death-ligand 1 (PD-L1) expression levels and immunotherapy responses.
RESULTS
In total, 84 patients were prospectively analyzed, of which 59 showed low (< 10%), and 25 showed high (≥ 10%) PD-L1 expression levels. The alpha and beta diversities did not significantly differ between the two groups. Veillonella dispar was dominant in the high-PD-L1 group; the population of Neisseria was significantly higher in the low-PD-L1 group than in the high-PD-L1 group. In the immunotherapy responder group, V. dispar was dominant, while Haemophilus influenzae and Neisseria perflava were dominant in the non-responder group.
CONCLUSION
The abundances of Neisseria and V. dispar differed significantly in relation to PD-L1 expression levels and immunotherapy responses.
Topics: Aged; Antineoplastic Agents, Immunological; B7-H1 Antigen; Biomarkers, Tumor; Carcinoma, Non-Small-Cell Lung; Female; Gene Expression Regulation, Neoplastic; Humans; Immunotherapy; Lung; Lung Neoplasms; Male; Microbiota; Middle Aged; Prospective Studies
PubMed: 34963470
DOI: 10.1186/s12931-021-01919-1 -
Antibiotics (Basel, Switzerland) Sep 2023Antifungal agents are widely used to specifically eliminate infections by fungal pathogens. However, the specificity of antifungal agents has been challenged by a few...
Antifungal agents are widely used to specifically eliminate infections by fungal pathogens. However, the specificity of antifungal agents has been challenged by a few studies demonstrating antibacterial inhibitory effects against and species. Here, we evaluated for the first time the potential effect of fluconazole, the most clinically used antifungal agent, on a human oral microbiota biofilm model. The results showed that biofilm viability on blood and mitis salivarius agar media was increased over time in the presence of fluconazole at clinically relevant concentrations, despite a reduction in biomass. Targeted PCR revealed a higher abundance of , and spp. in the fluconazole-treated samples compared to the control, while was reduced and spp were not significantly affected. Further, we tested the potential impact of fluconazole using single-species models. Our results, using and luciferase reporters, showed that planktonic growth was not significantly affected by fluconazole, whereas for , planktonic growth, but not biofilm viability, was inhibited at the highest concentration. Fluconazole's effects on biofilm biomass were concentration and time dependent. Exposure for 48 h to the highest concentration of fluconazole was associated with biofilms with the most increased biomass. Potential growth inhibitory effects were further tested using four non-streptococcal species. Among these, the planktonic growth of both and was inhibited by fluconazole. The data indicate bacterial responses to fluconazole that extend to a broader range of bacterial species than previously anticipated from the literature, with the potential to disturb biofilm communities.
PubMed: 37760729
DOI: 10.3390/antibiotics12091433