OralFusobacterium nucleatumsubsp.polymorphumbinds to human salivary α-amylase

Insight into the Role of Psychological Factors in Oral Mucosa Diseases

With the development of psychology and medicine, more and more diseases have found their psychological origins and associations, especially ulceration and other mucosal injuries, within the digestive system. However, the association of psychological factors with lesions of the oral mucosa, including oral squamous cell carcinoma (OSCC), burning mouth syndrome (BMS), and recurrent aphthous stomatitis (RAS), have not been fully characterized. In this review, after introducing the association between psychological and nervous factors and diseases, we provide detailed descriptions of the psychology and nerve fibers involved in the pathology of OSCC, BMS, and RAS, pointing out the underlying mechanisms and suggesting the clinical indications.

Stress-related salivary proteins affect the production of volatile sulfur compounds by oral bacteria

OBJECTIVE

To determine whether stress-related substances and sex hormones influence the growth and in vitro production of volatile sulfur compounds (VSCs) by Solobacterium moorei and Fusobacterium nucleatum.

MATERIALS AND METHODS

Bacteria growth and VSCs production were evaluated in the presence of alpha-amylase, beta-defensin-2, mucin, estradiol, and progesterone. Growth was evaluated by colony counting, and the production of the VSCs hydrogen sulfide (H₂ S) and methyl mercaptan (CH₃ SH) was measured using the Oral Chroma™ instrument.

RESULTS

Mucin induced the production of H₂ S by both bacteria, but had a slight inhibitory effect on CH₃ SH production by F. nucleatum. It also increased the viability of F. nucleatum. Alpha-amylase increased H₂ S production by S. moorei and CH₃ SH production by F. nucleatum, but had no effect on H₂ S production by F. nucleatum. No substance altered the viability of S. moorei. No effects of beta-defensin-2, estradiol, or progesterone were observed.

CONCLUSION

The salivary stress-related proteins mucin and alpha-amylase altered VSCs production by F. nucleatum and S. moorei, favoring H₂ S production. These findings are a step toward understanding the relation between stress and increased amounts of H₂ S.

Comparative genomics and evolution of the amylase-binding proteins of oral streptococci

Background

Successful commensal bacteria have evolved to maintain colonization in challenging environments. The oral viridans streptococci are pioneer colonizers of dental plaque biofilm. Some of these bacteria have adapted to life in the oral cavity by binding salivary α-amylase, which hydrolyzes dietary starch, thus providing a source of nutrition. Oral streptococcal species bind α-amylase by expressing a variety of amylase-binding proteins (ABPs). Here we determine the genotypic basis of amylase binding where proteins of diverse size and function share a common phenotype.

Results

ABPs were detected in culture supernatants of 27 of 59 strains representing 13 oral Streptococcus species screened using the amylase-ligand binding assay. N-terminal sequences from ABPs of diverse size were obtained from 18 strains representing six oral streptococcal species. Genome sequencing and BLAST searches using N-terminal sequences, protein size, and key words identified the gene associated with each ABP. Among the sequenced ABPs, 14 matched amylase-binding protein A (AbpA), 6 matched amylase-binding protein B (AbpB), and 11 unique ABPs were identified as peptidoglycan-binding, glutamine ABC-type transporter, hypothetical, or choline-binding proteins. Alignment and phylogenetic analyses performed to ascertain evolutionary relationships revealed that ABPs cluster into at least six distinct, unrelated families (AbpA, AbpB, and four novel ABPs) with no phylogenetic evidence that one group evolved from another, and no single ancestral gene found within each group. AbpA-like sequences can be divided into five subgroups based on the N-terminal sequences. Comparative genomics focusing on the abpA gene locus provides evidence of horizontal gene transfer.

Conclusion

The acquisition of an ABP by oral streptococci provides an interesting example of adaptive evolution.

Electronic supplementary material

The online version of this article (doi:10.1186/s12866-017-1005-7) contains supplementary material, which is available to authorized users.

The impact of antimicrobial photodynamic therapy on peri-implant disease: What mechanisms are involved in this novel treatment?

According to the American Academy of Implant Dentistry, 3 million Americans have dental implants, and this number is growing by 500,000 each year. Proportionally, the number of biological complications is also increasing. Among them, peri-implant disease is considered the most common cause of implant loss after osseointegration. In this context, microorganisms residing on the surfaces of implants and their prosthetic components are considered to be the primary etiologic factor for peri-implantitis. Some research groups have proposed combining surgical and non-surgical therapies with systemic antibiotics. The major problem associated with the use of antibiotics to treat peri-implantitis is that microorganisms replicate very quickly. Moreover, inappropriate prescription of antibiotics is not only associated with potential resistance but also and most importantly with the development of superinfections that are difficult to eradicate. Although antimicrobial photodynamic therapy (aPDT) was discovered several years ago, aPDT has only recently emerged as a possible alternative therapy against different oral pathogens causing peri-implantitis. The mechanism of action of aPDT is based on a combination of a photosensitizer drug and light of a specific wavelength in the presence of oxygen. The reaction between light and oxygen produces toxic forms of oxygen species that can kill microbial cells. This mechanism is crucial to the efficacy of aPDT. To help us understand conflicting data, it is necessary to know all the particularities of the etiology of peri-implantitis and the aPDT compounds. We believe that this review will draw attention to new insights regarding the impact of aPDT on peri-implant disease.