The oral microbiome plays a vital role in maintaining oral and overall health and affects immune responses, digestion, and pathogen suppression. While most studies focus on age groups prone to specific conditions, such as dental caries in children or periodontal disease in older adults, limited data exist on preschool-aged children and young adults. This study investigates the composition and diversity of the oral microbiome between these age groups for enhanced understanding of a healthy oral microbiome. Microbial samples from the supragingival regions of 41 children and 31 young adults in Korea were analyzed using 16S rRNA gene sequencing. Alpha and beta diversity were assessed, and linear discriminant analysis effect size (LEfSe) identified taxa with significant differences in abundance between the groups. No significant differences in alpha diversity were observed between children and young adults however, beta diversity analysis revealed notably compositional differences. At the phylum level, Firmicutes were more abundant in children, whereas Actinobacteria were more prevalent in young adults. Genera such as Veillonella and Lautropia were more abundant among children, whereas Haemophilus and Rothia were more common among young adults. LEfSe analysis identified Veillonella rogosae and Lautropia mirabilis as more abundant in children, whereas Haemophilus parainfluenzae and Rothia dentocariosa were more prevalent in young adults. The observed differences suggest that children’s microbiomes are associated with biofilm development, while young adults’ microbiomes involve biofilm maturation and immune modulation. These findings highlight the age-related shift in oral microbiome composition, emphasizing the importance of monitoring these changes to support long-term oral health.

Endoplasmic reticulum (ER) stress, caused by the accumulation of misfolded or unfolded proteins, activates the unfolded protein response to maintain cellular homeostasis and is implicated in bacterial infections. This study investigated ER stress activation in THP-1-derived macrophages infected with oral bacteria Porphyromonas gingivalis , Prevotella intermedia , Aggregatibacter actinomycetemcomitans , and Streptococcus oralis at an multiplicity of infection of 50 for 4 hours. mRNA and protein expressions related to ER stress were analyzed by real-time polymerase chain reaction and Western blot, while pro-inflammatory cytokines were measured using enzymelinked immunosorbent assay. P. gingivalis induced the highest mRNA expression of XBP1 and PERK, whereas A. actinomycetemcomitans showed elevated GRP78, ATF6, IRE1α, ATF4, and CHOP. P. intermedia strongly expressed PERK, while S. oralis showed higher GRP78, PERK, ATF4, and CHOP expression. Protein analysis revealed S. oralis had the highest phosphorylation levels of eIF2α and IRE1α, while CHOP was most highly expressed in P. intermedia . Pro-inflammatory cytokine expression showed P. intermedia and P. gingivalis elicited the most TNF-α, while P. gingivalis induced the highest IL-1β levels. These findings suggest oral bacteria induce varying levels of ER stress, influencing the progression of oral infectious diseases. Targeting ER stress could offer therapeutic potential for managing inflammatory conditions like periodontitis.

본 연구는 관상가치가 있는 자생 참두메부추와 갯부추를 절화소재로 이용하고자 수행되었다. 실험은 절화가 수확된 직후, gibberellic acid(GA3) 50, 75, 100mg·L-1, silver thiosulfate(STS) 0.1, 0.3, 0.5mM, 8-hydroxyquinoline sulfate(8-HQS) 25, 50, 100mg·L-1, 그리고 시중에 판매되 고 있는 Chrysal 8mL·L-1, Floralife 10mL·L-1의 보존용액 에 처리되었다. 참두메부추의 절화수명 연장에는 Chrysal 보 존용액 처리가 가장 효과적이었으며 다음으로 75mg·L-1 GA3 처리가 효과적이었다. 한편 8-HQS와 STS는 참두메부추의 절화수명을 단축하고 줄기가 갈변하는 등의 부정적인 영향을 끼쳤다. Chrysal과 더불어 Floralife 보존용액 처리는 절화 참두메부추의 상대 생체중변화율을 높이는데 효과가 있었다. 반면 갯부추는 100mg·L-1 GA3 처리에서 절화수명이 유일하 게 7일까지 연장되었다. GA3 보존용액 처리를 제외한 다른 처리에서 갯부추의 절화수명은 증류수인 대조구보다 비슷하 거나 약간 높은 수준이었다. 절화 갯부추의 수분흡수율은 실 험 초반 100mg·L-1 8-HQS 처리에서, 상대 생체중변화율은 Chrysal 보존용액 처리에서 가장 높게 조사되었으나 두 처 리 모두 절화수명이 유의하게 연장되지 않았다. 갯부추는 100mg·L-1 GA3 처리에서 절화수명을 비롯한 절화품질이 가 장 우수하였다.

Inflammation is a protective mechanism against pathogens, but if maintained continuously, it destroys tissue structures. Aggregatibacter actinomycetemcomitans is a gram-negative, facultative anaerobic bacterium often found in severe periodontitis. A. actinomycetemcomitans invades epithelial cells and triggers inflammatory response in the immune cells. In this study, we investigated the effect of water-soluble rosehip extract on A. actinomycetemcomitansinduced inflammatory responses. A human monocytic cell line (THP-1) was differentiated to macrophages by phorbol 12-mystristate 13-acetate treatment. The cytotoxic effect of extract was determined using the 3-(4,5-dimethylthiazol-2- yl)-2,5-diphenyltetrazolium bromide assay. The effects of extract on bacterial growth were examined by measuring the optical densities using a spectrophotometer. THP-1-derived macrophages were infected A. actinomycetemcomitans after extract treatment, and culture supernatants were analyzed for cytokine production using enzyme-linked immunosorbent assay. Protein expression was measured by western blotting. Extract was not toxic to THP-1- derived macrophages. A. actinomycetemcomitans growth was inhibited by 1% extract. The extract suppressed A. actinomycetemcomitans-induced tumor necrosis factor-α, interleukin (IL)-1β, and IL-8 production. It also decreased mitogen-activated protein kinase (MAP kinase) and nuclear factor-κB (NF-κB) phosphorylation. Moreover, the extract inhibited the expression of inflammasome components, including nucleotide-binding oligomerization domain-like receptor pyrin domain-containing protein 3, Absent in Melanoma 2, and apoptosis associated speck-like protein containing a CARD. And cysteine-aspartic proteases-1 and IL-1β expression were decreased by the extract. In summary, extract suppressed A. actinomycetemcomitans growth and decreased inflammatory cytokine production by inhibiting activation of MAP kinase, NF-κB, and inflammasome signaling. Rosehip extract could be effective in the treatment of periodontal inflammation induced by A. actinomycetemcomitans infection.

본 연구는 다양한 보존용액이 절화 수명에 미치는 영향과, 절단된 두메부추(Allium dumebuchum H.J.Choi)의 줄기의 수분흡수율 및 상대 생체중을 평가하여 두메부추를 절화로 개발 하기 위해 수행되었다. 두메부추 절화가 수확된 후, gibberellic acid(GA3) 50, 75, 100mg･L-1, 8-hydroxyquinoline sulfate(8-HQS) 25, 50, 100mg･L-1, silver thiosulfate(STS) 0.1, 0.3, 0.5mM, 그리고 Chrysal 8mL･L-1, Floralife 10mL･L-1의 보존용액에 처리되었다. 실험기간 동안 환경조건으로 온도는 24℃로 유지되었으며 상대 습도 43±2.1%, 평균 광도는 22.81±1.2μmol･m- 2･s-1, 일장은 9/15h이었다. 두메부추의 절화수명은 대조구인 절화에서 9.0일로 조사된 것에 비해 GA3 100mg･L-1 보존용액 처리된 절화에서 14.0일로 가장 높게 측정되었다. 수분흡 수율 또한 GA3 100mg･L-1 처리에서 실험이 종료되는 시점에 0.07mL･g-1･d-1로 조사되어 다른 처리보다 높았다. 상대 생체 중은 시판중인 절화수명 연장제 Floralife와 Chrysal 보존용액 처리가 GA3 처리보다 유의하게 높게 조사되었다. GA3를 절화 보존용액으로 사용한 결과, 두메부추는 다른 처리들에 비해 높은 수분흡수율로 절화수명이 대조구보다 평균 5일이상 연장 되었다. 그러나, 8-HQS와 STS 보존용액 처리는 대조구에 비하여 두메부추 절화수명에 큰 차이가 없었다.

Accurate identification of microbes facilitates the prediction, prevention, and treatment of human diseases. To increase the accuracy of microbiome data analysis, a long region of the 16S rRNA is commonly sequenced via paired-end sequencing. In paired-end sequencing, a sufficient length of overlapping region is required for effective joining of the reads, and high-quality sequencing reads are needed at the overlapping region. Trimming sequences at the reads distal to a point where sequencing quality drops below a specific threshold enhance the joining process. In this study, we examined the effect of trimming conditions on the number of reads that remained after quality control and chimera removal in the Illumina paired-end reads of the V3–V4 hypervariable region. We also examined the alpha diversity and taxa assigned by each trimming condition. Optimum quality trimming increased the number of good reads and assigned more number of operational taxonomy units. The pre-analysis trimming step has a great influence on further microbiome analysis, and optimized trimming conditions should be applied for Divisive Amplicon Denoising Algorithm 2 analysis in QIIME2 platform.

Streptococcus mutans and Streptococcus sobrinus play important roles in dental caries. Coptis chinensis is a natural product with antimicrobial activity against enterobacteria; however, its effects on oral streptococci are still unknown. Therefore, the effects of C. chinensis on the growth and biofilm formation of the representative cariogenic bacteria S. mutans and S. sobrinus were investigated for the possible use of C. chinensis as an anticaries agent. The C. chinensis extract was diluted with sterile distilled water, and 0.1–2.5% of the extract was used in the experiment. The effects of the C. chinensis extract on the growth and glucan formation of S. mutans and S. sobrinus were measured by viable cell counting and spectrophotometry at 650 nm absorbance, respectively. Crystal violet staining was also carried out to confirm the C. chinensis extract’s inhibitory effect on biofilm formation. The C. chinensis extract significantly inhibited the growth of S. mutans and S. sobrinus at concentrations of ≥ 0.3% as compared with the control group. The viable cell count of colonies decreased by 1.7-fold and 1.2-fold at 2.5% and 1.25%, respectively, compared with the control group. The biofilm formation of S. mutans and S. sobrinus was inhibited by > 20-fold at C. chinensis extract concentrations of ≥ 1.25% as compared with the control group. In summary, the C. chinensis extract inhibited the growth and biofilm and glucan formation of S. mutans and S. sobrinus . Therefore, C. chinensis might be a potential candidate for controlling dental caries.

The purpose of this study was to identify the oral bacterial species in sequestra from patients with bisphosphonate-related osteonecrosis of the jaw (BRONJ). Fifteen patients with BRONJ (2 males and 13 females) were evaluated. Clinical features, radiographic findings, and bisphosphonate intake history were investigated. All patients were treated with surgical methods (curettage or sequestrectomy). Infected bone samples were collected from the affected BRONJ site. Ten bacterial species were selected for polymerase chain reaction (PCR) detection. Two to nine bacterial species were detected by PCR. Gram-negative species were predominant and all identified bacteria were anaerobes. Porphyromonas gingivalis, Tannerella forsythia, and Treponema denticola were detected at high levels. These are major pathogenic species in periodontal disease. Orthopantomographic radiographs showed generalized alveolar bone loss in most patients. These radiographic findings may provide evidence of chronic periodontitis as a pre-existing inflammatory disease. Most patients had experienced a predisposing dental procedure, such as tooth extraction. Sequestra (necrotic bone) infected with oral bacterial species may be an important risk factor for BRONJ. As such, prevention and management of BRONJ may rely on effective control of bacteria in the oral cavity.

Xylitol is well-known to have an anti-caries effect by inhibiting the replication of cariogenic bacteria. In addition, xylitol enhances saliva secretion. However, the precise molecular mechanism of xylitol on saliva secretion is yet to be elucidated. Thus, in this study, we aimed to investigate the stimulatory effect of xylitol on saliva secretion and to further evaluate the involvement of xylitol in muscarinic type 3 receptor (M3R) signaling. For determining these effects, we measured the saliva flow rate following xylitol treatment in healthy individuals and patients with dry mouth. We further tested the effects of xylitol on M3R signaling in human salivary gland (HSG) cells using realtime quantitative reverse-transcriptase polymerase chain reaction, immunoblotting, and immunostaining. Xylitol candy significantly increased the salivary flow rate and intracellular calcium release in HSG cells via the M3R signaling pathway. In addition, the expressions of M3R and aquaporin 5 were induced by xylitol treatment. Lastly, we investigated the distribution of M3R and aquaporin 5 in HSG cells. Xylitol was found to activate M3R, thereby inducing increases in Ca2+ concentration. Stimulation of the muscarinic receptor induced by xylitol activated the internalization of M3R and subsequent trafficking of aquaporin 5. Taken together, these findings suggest a molecular mechanism for secretory effects of xylitol on salivary epithelial cells.

breakdown of tooth-supporting tissues, producing dentition loss. Porphyromonas gingivalis (P. gingivalis), a Gramnegative anaerobic rod, is one of the major pathogens associated with periodontitis. Neutrophils are first line defense cells in the oral cavity that play a significant role in inflammatory response. Xylitol is a known anti-caries agent and has anti-inflammatory effects. In this study, we conducted experiments to evaluate anti-inflammatory effects of xylitol on P. gingivalis infected neutrophils for possible usage in prevention and treatment of periodontal infections. P. gingivalis was intraperitoneally injected and peritoneal lavage was collected for cytokine determination. For in vitro study, neutrophils were collected from mouse peritoneal cells after zymosan injection or bone marrow cells. Neutrophils were stimulated with live P. gingivalis and ELISA was used to determine the effect of xylitol on P. gingivalis induced cytokine production. IL-1β, IL-6, TNF-α concentration and neutrophil population in the peritoneal lavage was increased in P. gingivalis-infected mouse. Peritoneal cells infected with live P. gingivalis revealed significantly increased production of IL-1β, IL-6 and TNF-α at multiplicity of infection of 10. Neutrophils from bone marrow and peritoneal lavage revealed increased production of IL-1β, IL-6 and TNF-α. Xylitol significantly mitigated P. gingivalis induced cytokine production in neutrophils. Findings indicate that xylitol is an anti-inflammatory agent in neutrophils infected with live P. gingivalis, that suggests its use in periodontitis management.

Radiotherapy (RT) is a mainstay in the treatment of head and neck squamous cell carcinoma (HNSCC). For locally advanced HCSCC, concurrent chemoradiotherapy (CCRT) benefits HCSCC patients in terms of better survival and loco-regional control. In this study, we evaluated changes in oral microbiota in patients, who received CCRT for head and neck cancer. Oral rinsed samples were weekly collected before and during CCRT and at 4 weeks following treatment from HNSCC patients, who had received 70 Gy of radiation delivered to the primary sites for over 7 weeks and concurrent chemotherapy. Oral microbiota changes in three patients were analyzed by next-generation sequencing using 16S rRNA 454 pyrosequencing. On an average, 15,000 partial 16S rRNA gene sequences were obtained from each sample. All sequences fell into 11 different bacterial phyla. During early CCRT, the microbial diversity gradually decreased. In a patient, who did not receive any antibiotics during the CCRT, Firmicutes and Proteobacteria were the most abundant phylum. During the early CCRT, proteobacteria gradually decreased while Firmicutes increased. During the late CCRT, firmicutes gradually decreased while Bacteroides and Fusobacteria increased. In all the patients, yellow complex showed a gradual decrease, while orange and red complex showed a gradual increase during the CCRT. At 4 weeks after CCRT, the recovery of oral microbiota diversity was limited. During CCRT, there was a gradual increase in major periodontopathogens in association with the deterioration of the oral hygiene. Henceforth, it is proposed that understanding oral microbiota shift should provide better information for the development of effective oral care programs for patients receiving CCRT for HNSCC.

Mitochondria participate in various intracellular metabolic pathways such as generating intracellular ATP, synthesizing several essential molecules, regulating calcium homeostasis, and producing the cell’s reactive oxygen species (ROS). Emerging studies have demonstrated newly discovered roles of mitochondria, which participate in the regulation of innate immune responses by modulating NLRP3 inflammasomes. Here, we review the recently proposed pathways to be involved in mitochondria-mediated regulation of inflammasome activation and inflammation: 1) mitochondrial ROS, 2) calcium mobilization, 3) nicotinamide adenine dinucleotide (NAD+) reduction, 4) cardiolipin, 5) mitofusin, 6) mitochondrial DNA, 7) mitochondrial antiviral signaling protein. Furthermore, we highlight the significance of mitophagy as a negative regulator of mitochondrial damage and NLRP3 inflammasome activation, as potentially helpful therapeutic approaches which could potentially address uncontrolled inflammation.