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Tjokro NO, Marks CB, Wu A, Chen C. Dormancy-like Phenotype of Aggregatibacter actinomycetemcomitans: Survival during Famine. Pathogens 2024; 13:418. [PMID: 38787270 PMCID: PMC11124257 DOI: 10.3390/pathogens13050418] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2024] [Revised: 05/06/2024] [Accepted: 05/09/2024] [Indexed: 05/25/2024] Open
Abstract
Microbes frequently experience nutrient deprivations in the natural environment and may enter dormancy. Aggregatibacter actinomycetemcomitans is known to establish long-term infections in humans. This study examined the dormancy-like phenotype of an A. actinomycetemcomitans strain D7S-1 and its isogenic smooth-colony mutant D7SS. A tissue culture medium RPMI-1640 was nutrient-deficient (ND) and unable to support A. actinomycetemcomitans growth. RPMI-1640 amended with bases was nutrient-limited (NL) and supported limited growth of A. actinomycetemcomitans less than the nutrient-enriched (NE) laboratory medium did. Strain D7S-1, after an initial 2-log reduction in viability, maintained viability from day 4 to day 15 in the NL medium. Strain D7SS, after 1-log reduction in viability, maintained viability from day 3 to day 5. In contrast, bacteria in the NE medium were either non-recoverable (D7S-1; >6-log reduction) or continued to lose viability (D7SS; 3-log reduction) on day 5 and beyond. Scanning and transmission electron microscopy showed that A. actinomycetemcomitans in the NL medium formed robust biofilms similar to those in the NE medium but with evidence of stress. A. actinomycetemcomitans in the ND medium revealed scant biofilms and extensive cellular damage. We concluded that A. actinomycetemcomitans grown in the NL medium exhibited a dormancy-like phenotype characterized by minimum growth, prolonged viability, and distinct cellular morphology.
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Affiliation(s)
- Natalia O. Tjokro
- Department of Endodontics and Periodontics, Herman Ostrow School of Dentistry, University of Southern California, 925 W. 34th Street, Los Angeles, CA 90089, USA; (N.O.T.); (A.W.)
| | - Carolyn B. Marks
- Core Center of Excellence in Nano Imaging, University of Southern California, 1002 Childs Way, Los Angeles, CA 90089, USA;
| | - Ashley Wu
- Department of Endodontics and Periodontics, Herman Ostrow School of Dentistry, University of Southern California, 925 W. 34th Street, Los Angeles, CA 90089, USA; (N.O.T.); (A.W.)
| | - Casey Chen
- Department of Endodontics and Periodontics, Herman Ostrow School of Dentistry, University of Southern California, 925 W. 34th Street, Los Angeles, CA 90089, USA; (N.O.T.); (A.W.)
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Takada K, Nakano S, Nishio R, Muku D, Mochizuki S, Inui I, Okita K, Koga A, Watanabe K, Yoshioka Y, Ariyoshi W, Yamasaki R. Medicinal herbs, especially Hibiscus sabdariffa, inhibit oral pathogenic bacteria. J Oral Biosci 2024; 66:179-187. [PMID: 38278302 DOI: 10.1016/j.job.2024.01.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2023] [Revised: 01/14/2024] [Accepted: 01/15/2024] [Indexed: 01/28/2024]
Abstract
OBJECTIVES Medicinal herbs are plants with potential medicinal and health benefits. In recent years, they are being increasingly used as a treatment alternative owing to their effectiveness against various diseases. In this study, we investigated the inhibitory effects of 15 medicinal herbs on causative bacteria for dental caries and periodontal disease. METHODS This study evaluated the effects of the extracts of 15 medicinal herbs on growth and biofilm formation in five oral pathogenic bacterial strains. The herbs were processed into extracts, and bacterial strains were cultured. Then, bacterial growth and biofilm formation were assessed using various methods. Finally, the extract of the herb Hibiscus sabdariffa (hibiscus) was analyzed using high-performance liquid chromatography. RESULTS Incubation of bacteria with the herbal extracts showed that hibiscus exerted a significant inhibitory effect on all the oral pathogenic bacterial strains evaluated in this study. In addition, the pigment delphinidin-3-sambubioside, which is found in hibiscus extract, was identified as a particularly important inhibitory component. CONCLUSIONS These results lay the ground work for the potential development of novel therapeutic or preventive agents against dental caries and periodontal disease, two major oral diseases.
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Affiliation(s)
- Kazuya Takada
- Division of Infections and Molecular Biology, Department of Health Promotion, Kyushu Dental University, Kitakyushu, Fukuoka, 803-8580, Japan; Division of Developmental Stomatognathic Function Science, Department of Health Promotion, Kyushu Dental University, Kitakyushu, Fukuoka, 803-8580, Japan
| | - Shizuki Nakano
- Division of Infections and Molecular Biology, Department of Health Promotion, Kyushu Dental University, Kitakyushu, Fukuoka, 803-8580, Japan
| | - Reina Nishio
- Division of Infections and Molecular Biology, Department of Health Promotion, Kyushu Dental University, Kitakyushu, Fukuoka, 803-8580, Japan
| | - Daichi Muku
- Department of Chemistry and Biochemistry, The University of Kitakyushu, Kitakyushu, Fukuoka, 808-0135, Japan
| | - Shinichi Mochizuki
- Department of Chemistry and Biochemistry, The University of Kitakyushu, Kitakyushu, Fukuoka, 808-0135, Japan
| | - Inori Inui
- Division of Infections and Molecular Biology, Department of Health Promotion, Kyushu Dental University, Kitakyushu, Fukuoka, 803-8580, Japan
| | - Kaede Okita
- Division of Infections and Molecular Biology, Department of Health Promotion, Kyushu Dental University, Kitakyushu, Fukuoka, 803-8580, Japan
| | - Ayaka Koga
- Division of Infections and Molecular Biology, Department of Health Promotion, Kyushu Dental University, Kitakyushu, Fukuoka, 803-8580, Japan
| | - Koji Watanabe
- Division of Developmental Stomatognathic Function Science, Department of Health Promotion, Kyushu Dental University, Kitakyushu, Fukuoka, 803-8580, Japan
| | - Yoshie Yoshioka
- Division of Infections and Molecular Biology, Department of Health Promotion, Kyushu Dental University, Kitakyushu, Fukuoka, 803-8580, Japan
| | - Wataru Ariyoshi
- Division of Infections and Molecular Biology, Department of Health Promotion, Kyushu Dental University, Kitakyushu, Fukuoka, 803-8580, Japan
| | - Ryota Yamasaki
- Division of Infections and Molecular Biology, Department of Health Promotion, Kyushu Dental University, Kitakyushu, Fukuoka, 803-8580, Japan; Collaborative Research Centre for Green Materials on Environmental Technology, Kyushu Institute of Technology, Kitakyushu, Fukuoka, 804-8550, Japan.
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