ABSTRACT
The objective of this study was to investigate the compositional profiles and microbial shifts of oral microbiota during head-and-neck radiotherapy. Bioinformatic analysis based on 16S rRNA gene pyrosequencing was performed to assess the diversity and variation of oral microbiota of irradiated patients. Eight patients with head and neck cancers were involved in this study. For each patient, supragingival plaque samples were collected at seven time points before and during radiotherapy. A total of 147,232 qualified sequences were obtained through pyrosequencing and bioinformatic analysis, representing 3,460 species level operational taxonomic units (OTUs) and 140 genus level taxa. Temporal variations were observed across different time points and supported by cluster analysis based on weighted UniFrac metrics. Moreover, the low evenness of oral microbial communities in relative abundance was revealed by Lorenz curves. This study contributed to a better understanding of the detailed characterization of oral bacterial diversity of irradiated patients.
Subject(s)
Humans , Middle Aged , Actinomyces , Classification , Radiation Effects , Actinomycetaceae , Classification , Radiation Effects , Alcaligenaceae , Classification , Radiation Effects , Bacteria , Classification , Radiation Effects , Capnocytophaga , Classification , Radiation Effects , Carnobacteriaceae , Classification , Radiation Effects , Computational Biology , Dental Plaque , Microbiology , Follow-Up Studies , Gemella , Classification , Radiation Effects , Head and Neck Neoplasms , Radiotherapy , High-Throughput Nucleotide Sequencing , Neisseria , Classification , Radiation Effects , Prevotella , Classification , Radiation Effects , Propionibacteriaceae , Classification , Radiation Effects , RNA, Bacterial , RNA, Ribosomal, 16S , Streptococcus , Classification , Radiation Effects , Veillonella , Classification , Radiation EffectsABSTRACT
<p><b>AIM</b>The purpose of this study was to develop a mathematical model to quantitatively describe the passive transport of macromolecules within dental biofilms.</p><p><b>METHODOLOGY</b>Fluorescently labeled dextrans with different molecular mass (3 kD, 10 kD, 40 kD, 70 kD, 2000 kD) were used as a series of diffusion probes. Streptococcus mutans, Streptococcus sanguinis, Actinomyces naeslundii and Fusobacterium nucleatum were used as inocula for biofilm formation. The diffusion processes of different probes through the in vitro biofilm were recorded with a confocal laser microscope.</p><p><b>RESULTS</b>Mathematical function of biofilm penetration was constructed on the basis of the inverse problem method. Based on this function, not only the relationship between average concentration of steady-state and molecule weights can be analyzed, but also that between penetrative time and molecule weights.</p><p><b>CONCLUSION</b>This can be used to predict the effective concentration and the penetrative time of anti-biofilm medicines that can diffuse through oral biofilm. Furthermore, an improved model for large molecule is proposed by considering the exchange time at the upper boundary of the dental biofilm.</p>
Subject(s)
Actinomyces , Algorithms , Biofilms , Biological Transport , Dental Plaque , Microbiology , Dextrans , Pharmacokinetics , Diffusion , Fluorescent Dyes , Pharmacokinetics , Fusobacterium nucleatum , Macromolecular Substances , Pharmacokinetics , Microscopy, Confocal , Models, Biological , Molecular Probe Techniques , Streptococcus mutans , Streptococcus sanguisABSTRACT
<p><b>OBJECTIVE</b>To investigate the effect of Streptococcus mutans luxS mutarotation on the early biofilm formation.</p><p><b>METHODS</b>Based on the immobilization of magnetic beads by adherent cells, an assay of biofilm quantitative analysis was developed for the kinetic quantification of biofilm formation in this study. Streptococcus mutans luxS mutant strain was constructed and subject to this biofilm luxS mutant strain were compared.</p><p><b>RESULTS</b>The delta luxS mutant started to form a biofilm from the 6th hour (delta BFI = 2.015), and the delta BFI of luxS mutant increased more quickly than that of the wild type strain, until reaching a complete immobilization of the beads after 10 hours (delta BFI = 7.025). The wild-type strain start to form a biofilm from the 10 th hour (delta BFI = 1.875) and the beads were completely immobilized between 12 and 14 hours.</p><p><b>CONCLUSIONS</b>The luxS mutation can accelerate biofilm on a polystyrene surface during the mid-exponential growth phase. And a luxS-dependent signal may play an important role in the early biofilm formation of Streptococcus mutans.</p>
Subject(s)
Bacterial Proteins , Genetics , Biofilms , Carbon-Sulfur Lyases , Genetics , Gene Deletion , Gene Expression Regulation, Bacterial , Streptococcus mutans , GeneticsABSTRACT
<p><b>OBJECTIVE</b>To investigate the susceptibility of Streptococcus mutans (S. mutans) biofilms to antimicrobial agent by confocal laser scanning microscopy (CLSM).</p><p><b>METHODS</b>S. mutans biofilms formed in vitro on glass slice were acted on with penicillin of different concentrations for 3 h. Then these biofilms were stained by fluorescence and were observed by CLSM. The bacterial density and viability of biofilms were recorded.</p><p><b>RESULTS</b>When S. mutans biofilms were exposed to penicillin of 2 500 mg/L for 3 h, it was not completely killed. The higher the concentration of penicillin was, the weaker the biofilms against penicillin.</p><p><b>CONCLUSIONS</b>Compared with planktonic S. mutans, S. mutans biofilms produced stronger resistance to penicillin. It suggests that we should find new strategies to control the infection caused by biofilm in clinic.</p>