2026_Biofilm Inhibition of Aggregatibacter Actinomycetemcomitans By Probiotic Lactobacilli and Their Effect On the Expression of Targeted Virulence Genes
| Format: | General Document |
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| _version_ | 1860798364461826048 |
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| building | INTELEK Repository |
| collection | Online Access |
| collectionurl | https://intelek.unisza.edu.my/intelek/pages/search.php?search=!collection8803 |
| copyright | Copyright©PWB2026 |
| country | Malaysia |
| date | 2025-06-29 |
| format | General Document |
| id | 17474 |
| institution | UniSZA |
| originalfilename | BIOFILM INHIBITION OF Aggregatibacter actinomycetemcomitans BY PROBIOTIC LACTOBACILLI AND THEIR EFFECT ON THE EXPRESSION OF TARGETED VIRULENCE GENES (PHD_2025).pdf |
| person | Mohd Syakir Syahiran Che Mohd Noor |
| recordtype | oai_dc |
| resourceurl | https://intelek.unisza.edu.my/intelek/pages/view.php?ref=17474 |
| sourcemedia | Server storage Scanned document |
| spelling | 17474 https://intelek.unisza.edu.my/intelek/pages/view.php?ref=17474 https://intelek.unisza.edu.my/intelek/pages/search.php?search=!collection8803 General Document Malaysia Library Staff (Top Management) Library Staff (Management) Library Staff (Support) Terengganu Faculty of Health Sciences English application/pdf 1.6 Public Access Server storage Scanned document Universiti Sultan Zainal Abidin Universiti Sultan Zainal Abidin Dissertations, Academic 280 Quorum Sensing Periodontitis PDF Xpansion, Version 12.0.3.3 Copyright©PWB2026 Thesis Mohd Syakir Syahiran Che Mohd Noor Aggregatibacter Actinomycetemcomitans Probiotic Lactobacilli Biofilm Inhibition Periodontal Pathogen Virulence Gene Expression qseB and qseC genes Antibiofilm Activity Lactobacillus Periodontitis Biofilms Quorum Sensing (Microbiology) Probiotics Anti-bacterial Agents 2026_Biofilm Inhibition of Aggregatibacter Actinomycetemcomitans By Probiotic Lactobacilli and Their Effect On the Expression of Targeted Virulence Genes Aggregatibacter actinomycetemcomitans is one of the key pathogens in periodontitis and severe gum disease. Antibiotics are a common treatment for oral disease; however, the extracellular matrix of biofilms can impede antibiotic penetration, allowing bacteria to survive. Lactobacillus species have been extensively used in food and healthcare products and have potent activity against the periodontal pathogen biofilm. The qseB and qseC genes are involved in quorum sensing systems, whereas ygiW is involved in stress responses and gene regulation of biofilm formation in A. actinomycetemcomitans. The study aimed to evaluate the inhibition activity, targeted virulence gene expression, and the potential signaling pathway of the probiotic Lactobacilli against A. actinomycetemcomitans biofilm. Five Lactobacillus spp. and five A. actinomycetemcomitans strains were used for this study. The co-culture assay using the overlay agar method was carried out to determine the inhibition zone of probiotic Lactobacilli against A. actinomycetemcomitans. The antibiotic tetracycline was used as a positive control. In addition, the probiotic Lactobacilli cells and supernatants during exponential and stationary phases were used to assess the biofilm activity of A. actinomycetemcomitans using a biofilm inhibition assay. The RNA samples of the bacterial cells from the biofilm assay were extracted, and qPCR was carried out to quantify the nucleic acid sequences of qseB, qseC, and ygiW genes. Data from biological triplicates were presented as mean ± SD (standard deviation). The comparison was performed using Student’s t-test software, with a P-value < 0.05 as the significance level. A proposed signaling pathway was generated using BioRender software to understand the signaling pathway and biofilm inhibition with and without probiotic Lactobacilli. Weak and moderate inhibition activities were observed in probiotic Lactobacilli against all five strains of A. actinomycetemcomitans, except for L. casei NBRC 15883 against SUNY 75, which showed strong inhibition activity. For antibiofilm activity, probiotic Lactobacilli in the exponential phase showed a significant difference (P < 0.05) in biofilm formation against all five strains of A. actinomycetemcomitans, whereas probiotic Lactobacilli in the stationary phase showed no significant difference (P > 0.05) in biofilm formation against all A. actinomycetemcomitans strains except for OMZ 534 and Y4. For probiotic Lactobacilli cells, there was a significant difference (P < 0.05) in biofilm formation during exponential and stationary phases except for Y4 and ATCC 29524. When tested with probiotic Lactobacilli supernatant, there was no significant difference (P > 0.05) in biofilm formation during exponential and stationary phases against all five A. actinomycetemcomitans strains. The qseB, qseC, and ygiW gene expressions were significantly downregulated (P < 0.05) in the presence of probiotic Lactobacilli. A proposed signaling pathway was generated, suggesting disruption of the quorum sensing regulation by probiotic Lactobacilli on A. actinomycetemcomitans. Probiotic Lactobacilli can inhibit the biofilm formation activity of A. actinomycetemcomitans. Probiotic Lactobacilli were shown to exert an inhibitory effect on the targeted virulence gene expression of A. actinomycetemcomitans. The study on the signaling pathway suggests that probiotic Lactobacilli may interfere with the quorum sensing signals, thus inhibiting the biofilm formation of A. actinomycetemcomitans. This finding suggests a dynamic effect of probiotic Lactobacilli as part of counteraction strategies against the periodontal pathogen biofilm. uuid:0f0d31a9-d695-40de-a6a0-47cdfac6ee29 BIOFILM INHIBITION OF Aggregatibacter actinomycetemcomitans BY PROBIOTIC LACTOBACILLI AND THEIR EFFECT ON THE EXPRESSION OF TARGETED VIRULENCE GENES (PHD_2025).pdf 2025-06-29 |
| spellingShingle | 2026_Biofilm Inhibition of Aggregatibacter Actinomycetemcomitans By Probiotic Lactobacilli and Their Effect On the Expression of Targeted Virulence Genes |
| state | Terengganu |
| subject | Dissertations, Academic Lactobacillus Periodontitis Biofilms Quorum Sensing (Microbiology) Probiotics Anti-bacterial Agents |
| summary | Aggregatibacter actinomycetemcomitans is one of the key pathogens in periodontitis and severe gum disease. Antibiotics are a common treatment for oral disease; however, the extracellular matrix of biofilms can impede antibiotic penetration, allowing bacteria to survive. Lactobacillus species have been extensively used in food and healthcare products and have potent activity against the periodontal pathogen biofilm. The qseB and qseC genes are involved in quorum sensing systems, whereas ygiW is involved in stress responses and gene regulation of biofilm formation in A. actinomycetemcomitans. The study aimed to evaluate the inhibition activity, targeted virulence gene expression, and the potential signaling pathway of the probiotic Lactobacilli against A. actinomycetemcomitans biofilm. Five Lactobacillus spp. and five A. actinomycetemcomitans strains were used for this study. The co-culture assay using the overlay agar method was carried out to determine the inhibition zone of probiotic Lactobacilli against A. actinomycetemcomitans. The antibiotic tetracycline was used as a positive control. In addition, the probiotic Lactobacilli cells and supernatants during exponential and stationary phases were used to assess the biofilm activity of A. actinomycetemcomitans using a biofilm inhibition assay. The RNA samples of the bacterial cells from the biofilm assay were extracted, and qPCR was carried out to quantify the nucleic acid sequences of qseB, qseC, and ygiW genes. Data from biological triplicates were presented as mean ± SD (standard deviation). The comparison was performed using Student’s t-test software, with a P-value < 0.05 as the significance level. A proposed signaling pathway was generated using BioRender software to understand the signaling pathway and biofilm inhibition with and without probiotic Lactobacilli. Weak and moderate inhibition activities were observed in probiotic Lactobacilli against all five strains of A. actinomycetemcomitans, except for L. casei NBRC 15883 against SUNY 75, which showed strong inhibition activity. For antibiofilm activity, probiotic Lactobacilli in the exponential phase showed a significant difference (P < 0.05) in biofilm formation against all five strains of A. actinomycetemcomitans, whereas probiotic Lactobacilli in the stationary phase showed no significant difference (P > 0.05) in biofilm formation against all A. actinomycetemcomitans strains except for OMZ 534 and Y4. For probiotic Lactobacilli cells, there was a significant difference (P < 0.05) in biofilm formation during exponential and stationary phases except for Y4 and ATCC 29524. When tested with probiotic Lactobacilli supernatant, there was no significant difference (P > 0.05) in biofilm formation during exponential and stationary phases against all five A. actinomycetemcomitans strains. The qseB, qseC, and ygiW gene expressions were significantly downregulated (P < 0.05) in the presence of probiotic Lactobacilli. A proposed signaling pathway was generated, suggesting disruption of the quorum sensing regulation by probiotic Lactobacilli on A. actinomycetemcomitans. Probiotic Lactobacilli can inhibit the biofilm formation activity of A. actinomycetemcomitans. Probiotic Lactobacilli were shown to exert an inhibitory effect on the targeted virulence gene expression of A. actinomycetemcomitans. The study on the signaling pathway suggests that probiotic Lactobacilli may interfere with the quorum sensing signals, thus inhibiting the biofilm formation of A. actinomycetemcomitans. This finding suggests a dynamic effect of probiotic Lactobacilli as part of counteraction strategies against the periodontal pathogen biofilm. |
| title | 2026_Biofilm Inhibition of Aggregatibacter Actinomycetemcomitans By Probiotic Lactobacilli and Their Effect On the Expression of Targeted Virulence Genes |
| title_full | 2026_Biofilm Inhibition of Aggregatibacter Actinomycetemcomitans By Probiotic Lactobacilli and Their Effect On the Expression of Targeted Virulence Genes |
| title_fullStr | 2026_Biofilm Inhibition of Aggregatibacter Actinomycetemcomitans By Probiotic Lactobacilli and Their Effect On the Expression of Targeted Virulence Genes |
| title_full_unstemmed | 2026_Biofilm Inhibition of Aggregatibacter Actinomycetemcomitans By Probiotic Lactobacilli and Their Effect On the Expression of Targeted Virulence Genes |
| title_short | 2026_Biofilm Inhibition of Aggregatibacter Actinomycetemcomitans By Probiotic Lactobacilli and Their Effect On the Expression of Targeted Virulence Genes |
| title_sort | 2026_biofilm inhibition of aggregatibacter actinomycetemcomitans by probiotic lactobacilli and their effect on the expression of targeted virulence genes |