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Selvakumar DR, Krishnamoorthy S, Venkatesan K, Ramanathan A, Abbott PV, Angambakkam Rajasekaran P. Active Bacteria in Carious Dentin of Mandibular Molars with Different Pulp Conditions: An In Vivo Study. J Endod 2021; 47:1883-1889. [PMID: 34534554 DOI: 10.1016/j.joen.2021.08.018] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Revised: 08/25/2021] [Accepted: 08/26/2021] [Indexed: 10/20/2022]
Abstract
INTRODUCTION This study evaluated the relative abundance and ribosomal activity of selected bacteria in carious dentin of teeth with different pulp conditions. METHODS Thirty healthy patients with class I occlusal caries in molars were categorized into 3 groups based on the pulp diagnosis: normal pulp (NP, n = 10) with caries extending less than half the thickness of dentin (as assessed radiographically), reversible pulpitis (n = 10), and symptomatic irreversible pulpitis (n = 10) with caries extending more than two thirds of the thickness of dentin. Carious dentin samples were collected from the deepest part of the cavity and stored in RNAlater solution (Ambion Inc, Austin, TX). Eight bacterial taxa were evaluated from the samples: Streptococcus mutans, Lactobacillus fermentum, Veillonella, Actinomyces, Rothia dentocariosa, Olsenella profusa, Prevotella intermedia, and Bifidobacterium dentium. The 16S ribosomal RNA (rRNA) gene and 16S rRNA were quantified by real-time polymerase chain reaction and used to calculate the relative genome abundance and relative ribosomal abundance. The Fisher exact test was used to compare proportions between groups. The mean rank difference between the various groups was assessed using the Kruskal-Wallis test with the Bonferroni-Holm correction. RESULTS The reversible pulpitis group had significantly higher 16S rRNA gene and rRNA counts of Actinomyces (P < .001 and P = .002) and B. dentium (P = .005 and P = .007) relative to the NP group. The symptomatic irreversible pulpitis group had significantly higher 16S rRNA gene and rRNA counts of L. fermentum (P < .001 and P < .001), Actinomyces (P < .001 and P < .001), O. profusa (P < .001 and P < .001), P. intermedia (P = .001 and P = .002), and Bifidobacterium (P < .001 and P < .001) relative to the NP group. CONCLUSIONS Specific bacterial activity varies in carious dentin of teeth with different pulp conditions.
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Affiliation(s)
- Deepan Raj Selvakumar
- Department of Conservative Dentistry and Endodontics, Thai Moogambigai Dental College and Hospital, Dr. MGR Educational and Research Institute, Chennai, Tamilnadu, India
| | - Sridevi Krishnamoorthy
- Department of Conservative Dentistry and Endodontics, Thai Moogambigai Dental College and Hospital, Dr. MGR Educational and Research Institute, Chennai, Tamilnadu, India
| | - Keerthi Venkatesan
- Department of Conservative Dentistry and Endodontics, Thai Moogambigai Dental College and Hospital, Dr. MGR Educational and Research Institute, Chennai, Tamilnadu, India
| | | | - Paul Vincent Abbott
- UWA Dental School, The University of Western Australia, Nedlands, Western Australia, Australia
| | - PradeepKumar Angambakkam Rajasekaran
- Department of Conservative Dentistry and Endodontics, Thai Moogambigai Dental College and Hospital, Dr. MGR Educational and Research Institute, Chennai, Tamilnadu, India.
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Hu C, Li X, He M, Jiang P, Long A, Xu J. Effect of Ocean Acidification on Bacterial Metabolic Activity and Community Composition in Oligotrophic Oceans, Inferred From Short-Term Bioassays. Front Microbiol 2021; 12:583982. [PMID: 33716995 PMCID: PMC7952631 DOI: 10.3389/fmicb.2021.583982] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Accepted: 01/18/2021] [Indexed: 11/13/2022] Open
Abstract
Increasing anthropogenic CO2 emissions in recent decades cause ocean acidification (OA), affecting carbon cycling in oceans by regulating eco-physiological processes of plankton. Heterotrophic bacteria play an important role in carbon cycling in oceans. However, the effect of OA on bacteria in oceans, especially in oligotrophic regions, was not well understood. In our study, the response of bacterial metabolic activity and community composition to OA was assessed by determining bacterial production, respiration, and community composition at the low-pCO2 (400 ppm) and high-pCO2 (800 ppm) treatments over the short term at two oligotrophic stations in the northern South China Sea. Bacterial production decreased significantly by 17.1–37.1 % in response to OA, since bacteria with high nucleic acid content preferentially were repressed by OA, which was less abundant under high-pCO2 treatment. Correspondingly, shifts in bacterial community composition occurred in response to OA, with a high fraction of the small-sized bacteria and high bacterial species diversity in a high-pCO2 scenario at K11. Bacterial respiration responded to OA differently at both stations, most likely attributed to different physiological responses of the bacterial community to OA. OA mitigated bacterial growth efficiency, and consequently, a larger fraction of DOC entering microbial loops was transferred to CO2.
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Affiliation(s)
- Caiqin Hu
- State Key Laboratory of Tropical Oceanography, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, China.,College of Marine Science, University of Chinese Academy of Sciences, Beijing, China.,Southern Marine Science and Engineering Guangdong Laboratory, Guangzhou, China
| | - Xiangfu Li
- State Key Laboratory of Tropical Oceanography, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, China.,Southern Marine Science and Engineering Guangdong Laboratory, Guangzhou, China
| | - Maoqiu He
- State Key Laboratory of Tropical Oceanography, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, China.,College of Marine Science, University of Chinese Academy of Sciences, Beijing, China
| | - Peng Jiang
- College of Ocean and Earth Sciences, University of Xiamen, Xiamen, China
| | - Aimin Long
- State Key Laboratory of Tropical Oceanography, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, China.,College of Marine Science, University of Chinese Academy of Sciences, Beijing, China
| | - Jie Xu
- State Key Laboratory of Tropical Oceanography, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, China.,College of Marine Science, University of Chinese Academy of Sciences, Beijing, China.,Southern Marine Science and Engineering Guangdong Laboratory, Guangzhou, China.,Innovation Academy of South China Sea Ecology and Environmental Engineering, Chinese Academy of Sciences, Guangzhou, China
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