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Pei P, Aslam M, Wang H, Ye P, Li T, Liang H, Lin Q, Chen W, Du H. Diversity and ecological function of urease-producing bacteria in the cultivation environment of Gracilariopsis lemaneiformis. MICROBIAL ECOLOGY 2024; 87:35. [PMID: 38261068 PMCID: PMC10806000 DOI: 10.1007/s00248-023-02339-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2023] [Accepted: 12/27/2023] [Indexed: 01/24/2024]
Abstract
Urease-producing bacteria (UPB) provide inorganic nitrogen for primary producers by hydrolyzing urea, and play an important role in marine nitrogen cycle. However, there is still an incomplete understanding of UPB and their ecological functions in the cultivation environment of the red macroalgae Gracilariopsis lemaneiformis. This study comprehensively analyzed the diversity of culturable UPB and explored their effects on urea uptake by G. lemaneiformis. A total of 34 isolates belonging to four main bacterial phyla i.e. (Proteobacteria, Bacteroidetes, Firmicutes, and Actinobacteria) were identified through 16S rRNA sequencing and were screened for UPB by urea agar chromogenic medium assay and ureC gene cloning. Our data revealed that only 8 strains contained urease. All of these UPB exhibited different urease activities, which were determined by the Berthelot reaction colorimetry assay. Additionally, the UPB strain (G13) isolated from G. lemaneiformis with higher urease activity was selected for co-culture with G. lemaneiformis to explore its role in promoting or inhibiting nitrogen uptake by macroalgae. The results showed a significant increase in urea consumption in the culture medium and the total cellular nitrogen in G. lemaneiformis in the UPB-co culture group compared to the sterile group. This suggests that the selected UPB strain positively influences nitrogen uptake by G. lemaneiformis. Similarly, isotopic assays revealed that the δ15N content of G. lemaneiformis was significantly higher in the UPB-co culture than in the control group, where δ15N-urea was the only nitrogen source in the culture medium. This indicates that the UPB helped G. lemaneiformis to absorb more nitrogen from urea. Moreover, the highest content of δ15N was found in G. lemaneiformis with epiphytic bacteria compared to sterilized (i.e. control), showing that epiphytic bacteria, along with UPB, have a compound effect in helping G. lemaneiformis absorb more nitrogen from urea. Taken together, these results provide unique insight into the ecological role of UPB and suggest that urease from macroalgae environment-associated bacteria might be an important player in marine nitrogen cycling.
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Affiliation(s)
- Pengbing Pei
- Guangdong Provincial Key Laboratory of Marine Biotechnology, College of Science, Shantou University, Shantou, 515063, China
- Key Laboratory of Cultivation and High-Value Utilization of Marine Organisms in Fujian Province, Fisheries Research Institute of Fujian, Xiamen, 361000, China
| | - Muhammad Aslam
- Guangdong Provincial Key Laboratory of Marine Biotechnology, College of Science, Shantou University, Shantou, 515063, China
- Faculty of Marine Sciences, LUAWMS, Lasbela, 90150, Pakistan
| | - Hui Wang
- Guangdong Provincial Key Laboratory of Marine Biotechnology, College of Science, Shantou University, Shantou, 515063, China
| | - Peilin Ye
- Guangdong Provincial Key Laboratory of Marine Biotechnology, College of Science, Shantou University, Shantou, 515063, China
| | - Tangcheng Li
- Guangdong Provincial Key Laboratory of Marine Disaster Prediction and Prevention, College of Science, Shantou University, Shantou, 515063, China
| | - Honghao Liang
- Guangdong Provincial Key Laboratory of Marine Biotechnology, College of Science, Shantou University, Shantou, 515063, China
| | - Qi Lin
- Key Laboratory of Cultivation and High-Value Utilization of Marine Organisms in Fujian Province, Fisheries Research Institute of Fujian, Xiamen, 361000, China
| | - Weizhou Chen
- Guangdong Provincial Key Laboratory of Marine Biotechnology, College of Science, Shantou University, Shantou, 515063, China
| | - Hong Du
- Guangdong Provincial Key Laboratory of Marine Biotechnology, College of Science, Shantou University, Shantou, 515063, China.
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Robertsson C, Svensäter G, Blum Z, Jakobsson ME, Wickström C. Proteomic response in Streptococcus gordonii DL1 biofilm cells during attachment to salivary MUC5B. J Oral Microbiol 2021; 13:1967636. [PMID: 34447490 PMCID: PMC8386731 DOI: 10.1080/20002297.2021.1967636] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Background Salivary mucin MUC5B seems to promote biodiversity in dental biofilms, and thereby oral health, for example, by inducing synergistic ‘mucolytic’ activities in a variety of microbial species that need to cooperate for the release of nutrients from the complex glycoprotein. Knowledge of how early colonizers interact with host salivary proteins is integral to better understand the maturation of putatively harmful oral biofilms and could provide key insights into biofilm physiology. Methods The early oral colonizer Streptococcus gordonii DL1 was grown planktonically and in biofilm flow cell systems with uncoated, MUC5B or low-density salivary protein (LDP) coated surfaces. Bacterial cell proteins were extracted and analyzed using a quantitative mass spectrometry-based workflow, and differentially expressed proteins were identified. Results and conclusions Overall, the proteomic profiles of S. gordonii DL1 were similar across conditions. Six novel biofilm cell proteins and three planktonic proteins absent in all biofilm cultures were identified. These differences may provide insights into mechanisms for adaptation to biofilm growth in this species. Salivary MUC5B also elicited specific responses in the biofilm cell proteome. These regulations may represent mechanisms by which this mucin could promote colonization of the commensal S. gordonii in oral biofilms.
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Affiliation(s)
- Carolina Robertsson
- Department of Oral Biology and Pathology, Faculty of Odontology, Malmö University, Malmö, Sweden
| | - Gunnel Svensäter
- Department of Oral Biology and Pathology, Faculty of Odontology, Malmö University, Malmö, Sweden
| | - Zoltan Blum
- Department of Biomedical Science, Faculty of Health and Society, Malmö University, Malmö, Sweden
| | | | - Claes Wickström
- Department of Oral Biology and Pathology, Faculty of Odontology, Malmö University, Malmö, Sweden
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Dahlén G, Hassan H, Blomqvist S, Carlén A. Rapid urease test (RUT) for evaluation of urease activity in oral bacteria in vitro and in supragingival dental plaque ex vivo. BMC Oral Health 2018; 18:89. [PMID: 29776416 PMCID: PMC5960132 DOI: 10.1186/s12903-018-0541-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2017] [Accepted: 04/26/2018] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Urease is an enzyme produced by plaque bacteria hydrolysing urea from saliva and gingival exudate into ammonia in order to regulate the pH in the dental biofilm. The aim of this study was to assess the urease activity among oral bacterial species by using the rapid urease test (RUT) in a micro-plate format and to examine whether this test could be used for measuring the urease activity in site-specific supragingival dental plaque samples ex vivo. METHODS The RUT test is based on 2% urea in peptone broth solution and with phenol red at pH 6.0. Oral bacterial species were tested for their urease activity using 100 μl of RUT test solution in the well of a micro-plate to which a 1 μl amount of cells collected after growth on blood agar plates or in broth, were added. The color change was determined after 15, 30 min, and 1 and 2 h. The reaction was graded in a 4-graded scale (none, weak, medium, strong). Ex vivo evaluation of dental plaque urease activity was tested in supragingival 1 μl plaque samples collected from 4 interproximal sites of front teeth and molars in 18 adult volunteers. The color reaction was read after 1 h in room temperature and scored as in the in vitro test. RESULTS The strongest activity was registered for Staphylococcus epidermidis, Helicobacter pylori, Campylobacter ureolyticus and some strains of Haemophilus parainfluenzae, while known ureolytic species such as Streptococcus salivarius and Actinomyces naeslundii showed a weaker, variable and strain-dependent activity. Temperature had minor influence on the RUT reaction. The interproximal supragingival dental plaque between the lower central incisors (site 31/41) showed significantly higher scores compared to between the upper central incisors (site 11/21), between the upper left first molar and second premolar (site 26/25) and between the lower right second premolar and molar (site 45/46). CONCLUSION The rapid urease test (RUT) in a micro-plate format can be used as a simple and rapid method to test urease activity in bacterial strains in vitro and as a chair-side method for testing urease activity in site-specific supragingival plaque samples ex vivo.
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Affiliation(s)
- Gunnar Dahlén
- Department of Oral Microbiology and Immunology, Institute of Odontology, Sahlgrenska Academy, University of Gothenburg, Box 450, SE 40530 Gothenburg, Sweden
| | - Haidar Hassan
- Department of Oral Microbiology and Immunology, Institute of Odontology, Sahlgrenska Academy, University of Gothenburg, Box 450, SE 40530 Gothenburg, Sweden
| | - Susanne Blomqvist
- Department of Oral Microbiology and Immunology, Institute of Odontology, Sahlgrenska Academy, University of Gothenburg, Box 450, SE 40530 Gothenburg, Sweden
| | - Anette Carlén
- Department of Oral Microbiology and Immunology, Institute of Odontology, Sahlgrenska Academy, University of Gothenburg, Box 450, SE 40530 Gothenburg, Sweden
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Liu YL, Nascimento M, Burne RA. Progress toward understanding the contribution of alkali generation in dental biofilms to inhibition of dental caries. Int J Oral Sci 2012; 4:135-40. [PMID: 22996271 PMCID: PMC3465751 DOI: 10.1038/ijos.2012.54] [Citation(s) in RCA: 115] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Alkali production by oral bacteria is believed to have a major impact on oral microbial ecology and to be inibitory to the initiation and progression of dental caries. A substantial body of evidence is beginning to accumulate that indicates the modulation of the alkalinogenic potential of dental biofilms may be a promising strategy for caries control. This brief review highlights recent progress toward understanding molecular genetic and physiologic aspects of important alkali-generating pathways in oral bacteria, and the role of alkali production in the ecology of dental biofilms in health and disease.
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Affiliation(s)
- Ya-Ling Liu
- Department of Oral Biology, College of Dentistry, University of Florida, Gainesville, FL, USA
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Nascimento MM, Gordan VV, Garvan CW, Browngardt CM, Burne RA. Correlations of oral bacterial arginine and urea catabolism with caries experience. ACTA ACUST UNITED AC 2009; 24:89-95. [PMID: 19239634 DOI: 10.1111/j.1399-302x.2008.00477.x] [Citation(s) in RCA: 133] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
BACKGROUND/AIM Alkali generation by oral bacteria plays a key role in plaque pH homeostasis and may be a major impediment to the development of dental caries. To determine if the capacity of oral samples to produce ammonia from arginine or urea was related to caries experience, the arginine deiminase system (ADS) and urease activity in saliva and dental plaque samples were measured in 45 adult subjects. METHODS The subjects were divided into three groups according to caries status; 13 caries-free (CF) individuals (decayed, missing, and filled teeth = 0); 21 caries-active (CA) individuals (decayed teeth >or= 4); and 11 caries-experienced (CE) individuals (decayed teeth = 0; missing and filled teeth > 0). Real-time polymerase chain reaction was used to quantify the proportion of certain acid- or alkali-producing organisms in the samples. RESULTS The amount of ammonia generated from the test substrates by plaque samples was generally higher than that produced by salivary samples in all groups. Significantly higher levels of salivary ADS activity and plaque urease activity were observed in CF subjects compared to CA subjects (P = 0.0004 and P = 0.014, respectively). The proportions of Streptococcus mutans from saliva and dental plaque of CA subjects were significantly higher than those from the CF group (P = 0.0153 and P = 0.0009, respectively). In the CA group, there was an inverse relationship between urease activity and the levels of S. mutans (P < 0.0001). CONCLUSION This study supports the theory that increased caries risk is associated with reduced alkali-generating capacity of the bacteria colonizing the oral cavity; providing compelling evidence to further our understanding of oral alkali-generation in health and disease.
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Affiliation(s)
- M M Nascimento
- Department of Operative Dentistry, College of Dentistry, University of Florida, Gaineseville, FL 32610, USA
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