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Farva K, Sattar H, Ullah H, Raziq A, Mehmood MD, Tareen AK, Sultan IN, Zohra Q, Khan MW. Phenotypic Analysis, Molecular Characterization, and Antibiogram of Caries-Causing Bacteria Isolated from Dental Patients. Microorganisms 2023; 11:1952. [PMID: 37630520 PMCID: PMC10457851 DOI: 10.3390/microorganisms11081952] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Revised: 07/23/2023] [Accepted: 07/26/2023] [Indexed: 08/27/2023] Open
Abstract
Dental caries is a biofilm-mediated, sugar-driven, multifactorial, dynamic disease that results in the phasic demineralization and remineralization of dental hard tissues. Despite scientific advances in cariology, dental caries remains a severe global concern. The aim of this study was to determine the optimization of microbial and molecular techniques for the detection of cariogenic pathogens in dental caries patients, the prevalence of cariogenic bacteria on the basis of socioeconomic, climatological, and hygienic factors, and in vitro evaluation of the antimicrobial activity of selected synthetic antibiotics and herbal extracts. In this study, oral samples were collected from 900 patients for bacterial strain screening on a biochemical and molecular basis. Plant extracts, such as ginger, garlic, neem, tulsi, amla, and aloe vera, were used to check the antimicrobial activity against the isolated strains. Synthetic antimicrobial agents, such as penicillin, amoxicillin, erythromycin, clindamycin, metronidazole, doxycycline, ceftazidime, levofloxacin, and ciprofloxacin, were also used to access the antimicrobial activity. Among 900 patients, 63% were males and 37% were females, patients aged between 36 and 58 (45.7%) years were prone to disease, and the most common symptom was toothache (61%). For oral diseases, 21% used herbs, 36% used antibiotics, and 48% were self-medicated, owing to sweets consumption (60.66%) and fizzy drinks and fast food (51.56%). Staphylococcus mutans (29.11%) and Streptococcus sobrinus (28.11%) were found as the most abundant strains. Seven bacterial strains were successfully screened and predicted to be closely related to genera S. sobrinus, S. mutans, Actinomyces naeslundii, Lactobacillus acidophilus, Eubacterium nodatum, Propionibacterium acidifaciens, and Treponema Pallidum. Among plant extracts, the maximum zone of inhibition was recorded by ginger (22.36 mm) and amla (20.01 mm), while among synthetic antibiotics, ciprofloxacin and levofloxacin were most effective against all microbes. This study concluded that phyto extracts of ginger and amla were considered suitable alternatives to synthetic antibiotics to treat dental diseases.
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Affiliation(s)
- Khushbu Farva
- Institute of Molecular Biology and Biotechnology, The University of Lahore, Lahore 54000, Pakistan
| | - Huma Sattar
- Institute of Molecular Biology and Biotechnology, The University of Lahore, Lahore 54000, Pakistan
| | - Hayat Ullah
- Metabolic Engineering Lab, Department of Biological Engineering, Utah State University, Logan, UT 84322, USA
| | - Abdur Raziq
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, School of Bioengineering, Dalian University of Technology, Dalian 116024, China
| | - Muhammad Danish Mehmood
- Institute of Molecular Biology and Biotechnology, The University of Lahore, Lahore 54000, Pakistan
| | - Afrasiab Khan Tareen
- Department of Biotechnology, Balochistan University of Information Technology Engineering and Management Sciences, Quetta 87300, Pakistan
| | - Imrana Niaz Sultan
- Department of Biotechnology, Balochistan University of Information Technology Engineering and Management Sciences, Quetta 87300, Pakistan
| | - Quratulaain Zohra
- Department of Biotechnology, Project of Sahara for Life Trust, The Sahara College Narowal, Punjab 51601, Pakistan
| | - Muhammad Waseem Khan
- Department of Biotechnology, Balochistan University of Information Technology Engineering and Management Sciences, Quetta 87300, Pakistan
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Oh BS, Ryu SW, Yu SY, Bak JE, Choi WJ, Kim JS, Lee JS, Park SH, Kang SW, Lee J, Lee MK, Jung WY, Kim JE, Choi YH, Kim HB, Kim JK, Lee JH, Lee JH. Collinsella urealyticum sp. nov., a urease-positive bacterial strain isolated from swine faeces. Arch Microbiol 2023; 205:156. [PMID: 37004685 DOI: 10.1007/s00203-023-03510-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Revised: 03/21/2023] [Accepted: 03/22/2023] [Indexed: 04/04/2023]
Abstract
A novel actinobacterial strain, designated AGMB00827T, was isolated from swine faeces. Strain AGMB00827T was obligately anaerobic, Gram-stain-positive, non-motile, non-spore-forming and rod-shaped bacterium. Comparative analyses based on the 16S rRNA gene and whole genome sequence revealed that strain AGMB00827T was affiliated to the genus Collinsella, and was most closely related to Collinsella vaginalis Marseille-P2666T (= KCTC 25056T). Biochemical analysis showed strain AGMB00827T was negative for catalase and oxidase. Interestingly, strain AGMB00827T possessed urease activity, which was determined by traditional methods (API test and Christensen's urea medium), unlike related strains. Furthermore, the major cellular fatty acids (> 10%) of the isolate were C18:1 ω9c, C16:0, C16:0 DMA and C18:2 ω9,12c DMA. Based on the whole genome sequence analysis, the DNA G + C content of strain AGMB00827T was 52.3%, and the genome size and numbers of rRNA and tRNA genes were 1,945,251 bp, 3 and 46, respectively. The average nucleotide identity and digital DNA-DNA hybridization values between strain AGMB00827T and C. vaginalis KCTC 25056 T were 71.0 and 23.2%, respectively. Additionally, the genome analysis revealed that strain AGMB00827T possesses urease gene cluster including ureABC and ureDEFG while the related strains do not have those genes, which is consistent with the urease activity. On the basis of polyphasic taxonomic approach, strain AGMB00827T represents a novel species within the genus Collinsella, for which the name Collinsella urealyticum sp. nov. is proposed. The type strain is AGMB00827T (= KCTC 25287T = GDMCC 1.2724T).
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Affiliation(s)
- Byeong Seob Oh
- Korean Collection for Type Cultures, Biological Resource Center, Korea Research Institute of Bioscience and Biotechnology, Jeongeup, 56212, Republic of Korea
| | - Seoung Woo Ryu
- Korean Collection for Type Cultures, Biological Resource Center, Korea Research Institute of Bioscience and Biotechnology, Jeongeup, 56212, Republic of Korea
| | - Seung Yeob Yu
- Korean Collection for Type Cultures, Biological Resource Center, Korea Research Institute of Bioscience and Biotechnology, Jeongeup, 56212, Republic of Korea
| | - Jeong Eun Bak
- Korean Collection for Type Cultures, Biological Resource Center, Korea Research Institute of Bioscience and Biotechnology, Jeongeup, 56212, Republic of Korea
| | - Won Jung Choi
- Korean Collection for Type Cultures, Biological Resource Center, Korea Research Institute of Bioscience and Biotechnology, Jeongeup, 56212, Republic of Korea
| | - Ji-Sun Kim
- Korean Collection for Type Cultures, Biological Resource Center, Korea Research Institute of Bioscience and Biotechnology, Jeongeup, 56212, Republic of Korea
| | - Jung-Sook Lee
- Korean Collection for Type Cultures, Biological Resource Center, Korea Research Institute of Bioscience and Biotechnology, Jeongeup, 56212, Republic of Korea
- University of Science and Technology (UST), Daejeon, 34113, Republic of Korea
| | - Seung-Hwan Park
- Korean Collection for Type Cultures, Biological Resource Center, Korea Research Institute of Bioscience and Biotechnology, Jeongeup, 56212, Republic of Korea
| | - Se Won Kang
- Korean Collection for Type Cultures, Biological Resource Center, Korea Research Institute of Bioscience and Biotechnology, Jeongeup, 56212, Republic of Korea
| | - Jiyoung Lee
- Korean Collection for Type Cultures, Biological Resource Center, Korea Research Institute of Bioscience and Biotechnology, Jeongeup, 56212, Republic of Korea
- University of Science and Technology (UST), Daejeon, 34113, Republic of Korea
| | - Mi-Kyung Lee
- Korean Collection for Type Cultures, Biological Resource Center, Korea Research Institute of Bioscience and Biotechnology, Jeongeup, 56212, Republic of Korea
- University of Science and Technology (UST), Daejeon, 34113, Republic of Korea
| | - Won Yong Jung
- Korean Bioinformation Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, 34141, Republic of Korea
| | - Jo Eun Kim
- National Institute of Animal Science, Cheonan, 31000, Republic of Korea
| | - Yo Han Choi
- National Institute of Animal Science, Cheonan, 31000, Republic of Korea
| | - Hyeun Bum Kim
- Department of Animal Resources Science, Dankook University, Cheonan, 31116, Republic of Korea
| | - Jae-Kyung Kim
- Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, Jeongeup, 56212, Republic of Korea
| | - Ju-Hoon Lee
- Department of Food and Animal Biotechnology, Department of Agricultural Biotechnology, Center for Food and Bioconvergence, Seoul National University, Seoul, 08826, Republic of Korea
| | - Ju Huck Lee
- Korean Collection for Type Cultures, Biological Resource Center, Korea Research Institute of Bioscience and Biotechnology, Jeongeup, 56212, Republic of Korea.
- University of Science and Technology (UST), Daejeon, 34113, Republic of Korea.
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3
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Schwarz J, Schumacher K, Brameyer S, Jung K. Bacterial battle against acidity. FEMS Microbiol Rev 2022; 46:6652135. [PMID: 35906711 DOI: 10.1093/femsre/fuac037] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2022] [Revised: 07/11/2022] [Accepted: 07/27/2022] [Indexed: 01/09/2023] Open
Abstract
The Earth is home to environments characterized by low pH, including the gastrointestinal tract of vertebrates and large areas of acidic soil. Most bacteria are neutralophiles, but can survive fluctuations in pH. Herein, we review how Escherichia, Salmonella, Helicobacter, Brucella, and other acid-resistant Gram-negative bacteria adapt to acidic environments. We discuss the constitutive and inducible defense mechanisms that promote survival, including proton-consuming or ammonia-producing processes, cellular remodeling affecting membranes and chaperones, and chemotaxis. We provide insights into how Gram-negative bacteria sense environmental acidity using membrane-integrated and cytosolic pH sensors. Finally, we address in more detail the powerful proton-consuming decarboxylase systems by examining the phylogeny of their regulatory components and their collective functionality in a population.
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Affiliation(s)
- Julia Schwarz
- Faculty of Biology, Microbiology, Ludwig-Maximilians-University München, Großhaderner Str. 2-4, 82152 Martinsried, Germany
| | - Kilian Schumacher
- Faculty of Biology, Microbiology, Ludwig-Maximilians-University München, Großhaderner Str. 2-4, 82152 Martinsried, Germany
| | - Sophie Brameyer
- Faculty of Biology, Microbiology, Ludwig-Maximilians-University München, Großhaderner Str. 2-4, 82152 Martinsried, Germany
| | - Kirsten Jung
- Faculty of Biology, Microbiology, Ludwig-Maximilians-University München, Großhaderner Str. 2-4, 82152 Martinsried, Germany
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Loharch S, Berlicki Ł. Rational Development of Bacterial Ureases Inhibitors. CHEM REC 2022; 22:e202200026. [PMID: 35502852 DOI: 10.1002/tcr.202200026] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Revised: 03/28/2022] [Indexed: 12/23/2022]
Abstract
Urease, an enzyme that catalyzes the hydrolysis of urea, is a virulence factor of various pathogenic bacteria. In particular, Helicobacter pylori, that colonizes the digestive tract and Proteus spp., that can infect the urinary tract, are related to urease activity. Therefore, urease inhibitors are considered as potential therapeutics against these infections. This review describes current knowledge of the structures, activity, and biological importance of bacterial ureases. Moreover, the structure-based design of several classes of bacterial urease inhibitors is presented and discussed. Phosphinic and phosphonic acids were applied as transition-state analogues, while Michael acceptors and ebselen derivatives were applied as covalent binders of cysteine residue. This review incorporates bacterial urease inhibitors from literature published between 2008 and 2021.
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Affiliation(s)
- Saurabh Loharch
- Department of Bioorganic Chemistry, Faculty of Chemistry, Wrocław University of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370, Wrocław, Poland
| | - Łukasz Berlicki
- Department of Bioorganic Chemistry, Faculty of Chemistry, Wrocław University of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370, Wrocław, Poland
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5
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Hailemariam S, Zhao S, He Y, Wang J. Urea transport and hydrolysis in the rumen: A review. ANIMAL NUTRITION (ZHONGGUO XU MU SHOU YI XUE HUI) 2021; 7:989-996. [PMID: 34738029 PMCID: PMC8529027 DOI: 10.1016/j.aninu.2021.07.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Revised: 07/02/2021] [Accepted: 07/08/2021] [Indexed: 11/29/2022]
Abstract
Inefficient dietary nitrogen (N) conversion to microbial proteins, and the subsequent use by ruminants, is a major research focus across different fields. Excess bacterial ammonia (NH3) produced due to degradation or hydrolyses of N containing compounds, such as urea, leads to an inefficiency in a host's ability to utilize nitrogen. Urea is a non-protein N containing compound used by ruminants as an ammonia source, obtained from feed and endogenous sources. It is hydrolyzed by ureases from rumen bacteria to produce NH3 which is used for microbial protein synthesis. However, lack of information exists regarding urea hydrolysis in ruminal bacteria, and how urea gets to hydrolysis sites. Therefore, this review describes research on sites of urea hydrolysis, urea transport routes towards these sites, the role and structure of urea transporters in rumen epithelium and bacteria, the composition of ruminal ureolytic bacteria, mechanisms behind urea hydrolysis by bacterial ureases, and factors influencing urea hydrolysis. This review explores the current knowledge on the structure and physiological role of urea transport and ureolytic bacteria, for the regulation of urea hydrolysis and recycling in ruminants. Lastly, underlying mechanisms of urea transportation in rumen bacteria and their physiological importance are currently unknown, and therefore future research should be directed to this subject.
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Affiliation(s)
- Samson Hailemariam
- State Key Laboratory of Animal Nutrition, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, 100193, China
- Dilla University, College of Agriculture and Natural Resource, Dilla P. O. Box 419, Ethiopia
| | - Shengguo Zhao
- State Key Laboratory of Animal Nutrition, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, 100193, China
| | - Yue He
- State Key Laboratory of Animal Nutrition, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, 100193, China
| | - Jiaqi Wang
- State Key Laboratory of Animal Nutrition, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, 100193, China
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6
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Campbell PM, Humphreys GJ, Summers AM, Konkel JE, Knight CG, Augustine T, McBain AJ. Does the Microbiome Affect the Outcome of Renal Transplantation? Front Cell Infect Microbiol 2020; 10:558644. [PMID: 33425774 PMCID: PMC7785772 DOI: 10.3389/fcimb.2020.558644] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2020] [Accepted: 11/17/2020] [Indexed: 12/31/2022] Open
Abstract
The role of the human microbiome in health and disease is becoming increasingly apparent. Emerging evidence suggests that the microbiome is affected by solid organ transplantation. Kidney transplantation is the gold standard treatment for End-Stage Renal Disease (ESRD), the advanced stage of Chronic Kidney Disease (CKD). The question of how ESRD and transplantation affect the microbiome and vice versa includes how the microbiome is affected by increased concentrations of toxins such as urea and creatinine (which are elevated in ESRD), whether restoration of renal function following transplantation alters the composition of the microbiome, and the impact of lifelong administration of immunosuppressive drugs on the microbiome. Changes in microbiome composition and activity have been reported in ESRD and in therapeutic immunosuppression, but the effect on the outcome of transplantation is not well-understood. Here, we consider the current evidence that changes in kidney function and immunosuppression following transplantation influence the oral, gut, and urinary microbiomes in kidney transplant patients. The potential for changes in these microbiomes to lead to disease, systemic inflammation, or rejection of the organ itself is discussed, along with the possibility that restoration of kidney function might re-establish orthobiosis.
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Affiliation(s)
- Paul M Campbell
- School of Health Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom
| | - Gavin J Humphreys
- School of Health Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom
| | - Angela M Summers
- Department of Renal and Pancreatic Transplantation, Manchester University NHS Foundation Trust, Manchester Academic Health Science Centre, Manchester, United Kingdom
| | - Joanne E Konkel
- Lydia Becker Institute of Immunology and Inflammation, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom
| | - Christopher G Knight
- School of Natural Sciences, Faculty of Science and Engineering, The University of Manchester, Manchester, United Kingdom
| | - Titus Augustine
- Department of Renal and Pancreatic Transplantation, Manchester University NHS Foundation Trust, Manchester Academic Health Science Centre, Manchester, United Kingdom
| | - Andrew J McBain
- School of Health Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom
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7
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Kataria R, Khatkar A. Lead Molecules for Targeted Urease Inhibition: An Updated Review from 2010 -2018. Curr Protein Pept Sci 2020; 20:1158-1188. [PMID: 30894105 DOI: 10.2174/1389203720666190320170215] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2018] [Revised: 02/01/2019] [Accepted: 03/15/2019] [Indexed: 12/14/2022]
Abstract
The field of enzyme inhibition is a tremendous and quickly growing territory of research. Urease a nickel containing metalloenzyme found in bacteria, algae, fungi, and plants brings hydrolysis of urea and plays important role in environmental nitrogen cycle. Apart from this it was found to be responsible for many pathological conditions due to its presence in many microorganisms such as H. Pylori, a ureolytic bacteria having urease which elevates pH of gastric medium by hydrolyzing urea present in alimentary canal and help the bacteria to colonize and spread infection. Due to the infections caused by the various bacterial ureases such as Bacillus pasteurii, Brucella abortus, H. pylori, H. mustelae, Klebsiella aerogenes, Klebsiella tuberculosis, Mycobacterium tuberculosis, Pseudomonas putida, Sporosarcina pasteurii and Yersinia enterocolitica, it has been the current topic of today's research. About a wide range of compounds from the exhaustive literature survey has been discussed in this review which is enveloped into two expansive classes, as Inhibitors from synthetic origin and Inhibitors from natural origin. Moreover active site details of enzyme, mechanism of catalysis of substrate by enzyme, uses of plant urease and its pathogenic behavior has been included in the current review. So, overall, this review article diagrams the current landscape of the developments in the improvements in the thriving field of urease inhibitory movement in medicinal chemistry from year 2010 to 2018, with an emphasis on mechanism of action of inhibitors that may be used for more development of recent and strong urease inhibitors and open up new doors for assist examinations in a standout amongst the most lively and promising regions of research.
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Affiliation(s)
- Ritu Kataria
- International Institute of Pharmaceutical Sciences, Sonepat, Haryana, India
| | - Anurag Khatkar
- Department of Pharmaceutical Sciences, Maharshi Dayanand University, Rohtak, Haryana, India
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8
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Abstract
Nickel is an essential cofactor for some pathogen virulence factors. Due to its low availability in hosts, pathogens must efficiently transport the metal and then balance its ready intracellular availability for enzyme maturation with metal toxicity concerns. The most notable virulence-associated components are the Ni-enzymes hydrogenase and urease. Both enzymes, along with their associated nickel transporters, storage reservoirs, and maturation enzymes have been best-studied in the gastric pathogen Helicobacter pylori, a bacterium which depends heavily on nickel. Molecular hydrogen utilization is associated with efficient host colonization by the Helicobacters, which include both gastric and liver pathogens. Translocation of a H. pylori carcinogenic toxin into host epithelial cells is powered by H2 use. The multiple [NiFe] hydrogenases of Salmonella enterica Typhimurium are important in host colonization, while ureases play important roles in both prokaryotic (Proteus mirabilis and Staphylococcus spp.) and eukaryotic (Cryptoccoccus genus) pathogens associated with urinary tract infections. Other Ni-requiring enzymes, such as Ni-acireductone dioxygenase (ARD), Ni-superoxide dismutase (SOD), and Ni-glyoxalase I (GloI) play important metabolic or detoxifying roles in other pathogens. Nickel-requiring enzymes are likely important for virulence of at least 40 prokaryotic and nine eukaryotic pathogenic species, as described herein. The potential for pathogenic roles of many new Ni-binding components exists, based on recent experimental data and on the key roles that Ni enzymes play in a diverse array of pathogens.
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Li J, Li Y, Zhou Y, Wang C, Wu B, Wan J. Actinomyces and Alimentary Tract Diseases: A Review of Its Biological Functions and Pathology. BIOMED RESEARCH INTERNATIONAL 2018; 2018:3820215. [PMID: 30225251 PMCID: PMC6129341 DOI: 10.1155/2018/3820215] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/09/2018] [Accepted: 07/02/2018] [Indexed: 02/06/2023]
Abstract
Actinomyces are nonmotile, filamentous, Gram-positive bacteria that cause actinomycosis in immunodeficiency patients. Although the prognosis of actinomycosis is good, the diagnosis of actinomycosis is quite difficult. Recent studies on actinomycosis have shown that Actinomyces play an important role in various biological and clinical processes, such as the formation of dental plaque and the degradation of organics in the gastrointestinal tract. Here, the distribution of Actinomyces in the digestive tract, and different biological effects of actinomycosis, and its clinical association with inflammatory diseases are discussed. Furthermore, an overview of the most commonly used treatment methods and drugs used to treat Actinomyces infected alimentary canal diseases is presented.
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Affiliation(s)
- Jun Li
- Department of Gastroenterology, General Hospital of PLA, No. 28 Fuxing Road, Haidian District, Beijing, 100853, China
| | - Ying Li
- Department of Oncology, General Hospital of PLA, No. 28 Fuxing Road, Haidian District, Beijing, 100853, China
| | - Yu Zhou
- Department of Nanlou Clinical Laboratory, General Hospital of PLA, No. 28 Fuxing Road, Haidian District, Beijing, 100853, China
| | - Changzheng Wang
- Department of Gastroenterology, General Hospital of PLA, No. 28 Fuxing Road, Haidian District, Beijing, 100853, China
| | - Benyan Wu
- Department of Gastroenterology, General Hospital of PLA, No. 28 Fuxing Road, Haidian District, Beijing, 100853, China
| | - Jun Wan
- Department of Gastroenterology, General Hospital of PLA, No. 28 Fuxing Road, Haidian District, Beijing, 100853, China
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10
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Fu MS, Coelho C, De Leon-Rodriguez CM, Rossi DCP, Camacho E, Jung EH, Kulkarni M, Casadevall A. Cryptococcus neoformans urease affects the outcome of intracellular pathogenesis by modulating phagolysosomal pH. PLoS Pathog 2018; 14:e1007144. [PMID: 29906292 PMCID: PMC6021110 DOI: 10.1371/journal.ppat.1007144] [Citation(s) in RCA: 71] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Revised: 06/27/2018] [Accepted: 06/05/2018] [Indexed: 01/22/2023] Open
Abstract
Cryptococcus neoformans is a facultative intracellular pathogen and its interaction with macrophages is a key event determining the outcome of infection. Urease is a major virulence factor in C. neoformans but its role during macrophage interaction has not been characterized. Consequently, we analyzed the effect of urease on fungal-macrophage interaction using wild-type, urease-deficient and urease-complemented strains of C. neoformans. The frequency of non-lytic exocytosis events was reduced in the absence of urease. Urease-positive C. neoformans manifested reduced and delayed intracellular replication with fewer macrophages displaying phagolysosomal membrane permeabilization. The production of urease was associated with increased phagolysosomal pH, which in turn reduced growth of urease-positive C. neoformans inside macrophages. Interestingly, the ure1 mutant strain grew slower in fungal growth medium which was buffered to neutral pH (pH 7.4). Mice inoculated with macrophages carrying urease-deficient C. neoformans had lower fungal burden in the brain than mice infected with macrophages carrying wild-type strain. In contrast, the absence of urease did not affect survival of yeast when interacting with amoebae. Because of the inability of the urease deletion mutant to grow on urea as a sole nitrogen source, we hypothesize urease plays a nutritional role involved in nitrogen acquisition in the environment. Taken together, our data demonstrate that urease affects fitness within the mammalian phagosome, promoting non-lytic exocytosis while delaying intracellular replication and thus reducing phagolysosomal membrane damage, events that could facilitate cryptococcal dissemination when transported inside macrophages. This system provides an example where an enzyme involved in nutrient acquisition modulates virulence during mammalian infection.
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Affiliation(s)
- Man Shun Fu
- Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, United States of America
| | - Carolina Coelho
- Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, United States of America
| | - Carlos M. De Leon-Rodriguez
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, New York, United States of America
| | - Diego C. P. Rossi
- Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, United States of America
| | - Emma Camacho
- Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, United States of America
| | - Eric H. Jung
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, New York, United States of America
| | - Madhura Kulkarni
- Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, United States of America
| | - Arturo Casadevall
- Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, United States of America
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, New York, United States of America
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11
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Jaffar N, Ishikawa Y, Mizuno K, Okinaga T, Maeda T. Mature Biofilm Degradation by Potential Probiotics: Aggregatibacter actinomycetemcomitans versus Lactobacillus spp. PLoS One 2016; 11:e0159466. [PMID: 27438340 PMCID: PMC4954673 DOI: 10.1371/journal.pone.0159466] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2016] [Accepted: 07/01/2016] [Indexed: 02/07/2023] Open
Abstract
The biofilm degradation of Aggregatibacter actinomycetemcomitans is essential as a complete periodontal disease therapy, and here we show the effects of potential probiotic bacteria such as Lactobacillus spp. for the biofilm of several serotypes of A. actinomycetemcomitans strains. Eight of the 13 species showed the competent biofilm degradation of ≥ 90% reduction in biofilm values in A. actinomycetemcomitans Y4 (serotype b) as well as four of the seven species for the biofilm of A. actinomycetemcomitans OMZ 534 (serotype e). In contrast, the probiotic bacteria did not have a big impact for the degradation of A. actinomycetemcomitans SUNY 75 (serotype a) biofilm. The dispersed A. actinomycetemcomitans Y4 cells through the biofilm detachment were still viable and plausible factors for the biofilm degradation were not due to the lactic acid and low pH conditions. The three enzymes, protease, lipase, and amylase may be responsible for the biofilm degradation; in particular, lipase was the most effective enzyme for the biofilm degradation of A. actinomycetemcomitans Y4 along with the protease activity which should be also important for the other serotypes. Remarkable lipase enzyme activities were detected from some of the potential probiotics and a supporting result using a lipase inhibitor presented corroborating evidence that lipase activity is one of the contributing factors for biofilm degradation outside of the protease which is also another possible factor for the biofilm of the other serotype of A. actinomycetemcomitans strains. On the other hand, the biofilm of A. actinomycetemcomitans SUNY 75 (serotype a) was not powerfully degraded by the lipase enzyme because the lipase inhibitor was slightly functional for only two of potential probiotics.
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Affiliation(s)
- Norzawani Jaffar
- Department of Biological Functions Engineering, Graduate School of Life Science and Systems Engineering, Kyushu Institute of Technology, Wakamatsu-ku, Kitakyushu, Japan
- Faculty of Health Sciences, Gong Badak Campus, Universiti Sultan Zainal Abidin (UniSZA), Kuala Terengganu, Terengganu Darul Iman, Malaysia
| | - Yuya Ishikawa
- Department of Biological Functions Engineering, Graduate School of Life Science and Systems Engineering, Kyushu Institute of Technology, Wakamatsu-ku, Kitakyushu, Japan
| | - Kouhei Mizuno
- Department of Materials Science and Chemical Engineering, Kitakyushu National College of Technology, Kitakyushu, Japan
| | - Toshinori Okinaga
- School of Oral Health Sciences, Faculty of Dentistry, Kyushu Dental University, Kitakyushu, Japan
| | - Toshinari Maeda
- Department of Biological Functions Engineering, Graduate School of Life Science and Systems Engineering, Kyushu Institute of Technology, Wakamatsu-ku, Kitakyushu, Japan
- Research Center for Advanced Eco-fitting Technology, Kyushu Institute of Technology, Kitakyushu, Japan
- * E-mail:
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Jin D, Zhao S, Wang P, Zheng N, Bu D, Beckers Y, Wang J. Insights into Abundant Rumen Ureolytic Bacterial Community Using Rumen Simulation System. Front Microbiol 2016; 7:1006. [PMID: 27446045 PMCID: PMC4923134 DOI: 10.3389/fmicb.2016.01006] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2016] [Accepted: 06/13/2016] [Indexed: 01/07/2023] Open
Abstract
Urea, a non-protein nitrogen for dairy cows, is rapidly hydrolyzed to ammonia by urease produced by ureolytic bacteria in the rumen, and the ammonia is used as nitrogen for rumen bacterial growth. However, there is limited knowledge with regard to the ureolytic bacteria community in the rumen. To explore the ruminal ureolytic bacterial community, urea, or acetohydroxamic acid (AHA, an inhibitor of urea hydrolysis) were supplemented into the rumen simulation systems. The bacterial 16S rRNA genes were sequenced by Miseq high-throughput sequencing and used to reveal the ureoltyic bacteria by comparing different treatments. The results revealed that urea supplementation significantly increased the ammonia concentration, and AHA addition inhibited urea hydrolysis. Urea supplementation significantly increased the richness of bacterial community and the proportion of ureC genes. The composition of bacterial community following urea or AHA supplementation showed no significant difference compared to the groups without supplementation. The abundance of Bacillus and unclassified Succinivibrionaceae increased significantly following urea supplementation. Pseudomonas, Haemophilus, Neisseria, Streptococcus, and Actinomyces exhibited a positive response to urea supplementation and a negative response to AHA addition. Results retrieved from the NCBI protein database and publications confirmed that the representative bacteria in these genera mentioned above had urease genes or urease activities. Therefore, the rumen ureolytic bacteria were abundant in the genera of Pseudomonas, Haemophilus, Neisseria, Streptococcus, Actinomyces, Bacillus, and unclassified Succinivibrionaceae. Insights into abundant rumen ureolytic bacteria provide the regulation targets to mitigate urea hydrolysis and increase efficiency of urea nitrogen utilization in ruminants.
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Affiliation(s)
- Di Jin
- State Key Laboratory of Animal Nutrition, Institute of Animal Sciences, Chinese Academy of Agricultural SciencesBeijing, China; Animal Science Unit, Gembloux Agro-Bio Tech, University of LiègeGembloux, Belgium
| | - Shengguo Zhao
- State Key Laboratory of Animal Nutrition, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences Beijing, China
| | - Pengpeng Wang
- State Key Laboratory of Animal Nutrition, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences Beijing, China
| | - Nan Zheng
- State Key Laboratory of Animal Nutrition, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences Beijing, China
| | - Dengpan Bu
- State Key Laboratory of Animal Nutrition, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences Beijing, China
| | - Yves Beckers
- Animal Science Unit, Gembloux Agro-Bio Tech, University of Liège Gembloux, Belgium
| | - Jiaqi Wang
- State Key Laboratory of Animal Nutrition, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences Beijing, China
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Xu B, Yang X, Zhang P, Ma Z, Lin H, Fan H. The arginine deiminase system facilitates environmental adaptability of Streptococcus equi ssp. zooepidemicus through pH adjustment. Res Microbiol 2016; 167:403-12. [PMID: 27068185 DOI: 10.1016/j.resmic.2016.03.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2015] [Revised: 03/29/2016] [Accepted: 03/29/2016] [Indexed: 10/22/2022]
Abstract
The arginine deiminase system (ADS) is a secondary metabolic system found in many different bacterial pathogens and it is often associated with virulence. Here, a systematic study of ADS functions in Streptococcus equi subsp. zooepidemicus (SEZ) was performed. Transcriptional levels of ADS operon genes were observed to be significantly increased when SEZ was grown under acidic conditions. We constructed arcA and arcD deletion mutants (SEZ ΔarcA and SEZ ΔarcD, respectively) and found that SEZ ΔarcA was unable to metabolize arginine and synthesize ammonia; however, arcD deletion resulted in an initial decrease in arginine consumption and ammonia production, followed by recovery to the levels of wild-type SEZ after 24 h of cultivation. Cell extracts of SEZ ΔarcA showed no arginine deiminase (AD) activity, whereas no difference in AD activity between SEZ ΔarcD and wild-type SEZ was observed. SEZ survival tests demonstrated a significant decrease in survival for SEZ ΔarcA, when compared with wild-type SEZ, under acidic conditions and in epithelial cells. These findings indicate that ADS in SEZ contributes to environmental adaptability via ammonia synthesis to reduce pH stress.
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Affiliation(s)
- Bin Xu
- College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, China
| | - Xinyi Yang
- College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, China
| | - Ping Zhang
- College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, China
| | - Zhe Ma
- College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, China; Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou 225009, China
| | - Huixing Lin
- College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, China
| | - Hongjie Fan
- College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, China; Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou 225009, China.
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Abstract
OBJECTIVE Urease enzymes produced by oral bacteria generate ammonia, which can have a significant impact on the oral ecology and, consequently, on oral health. To evaluate the relationship of urease with dental plaque microbial profiles in children as it relates to dental caries, and to identify the main contributors to this activity. METHODS 82 supragingival plaque samples were collected from 44 children at baseline and one year later, as part of a longitudinal study on urease and caries in children. DNA was extracted; the V3-V5 region of the 16S rRNA gene was amplified and sequenced using 454 pyrosequencing. Urease activity was measured using a spectrophotometric assay. Data were analyzed with Qiime. RESULTS Plaque urease activity was significantly associated with the composition of the microbial communities of the dental plaque (Baseline P = 0.027, One Year P = 0.012). The bacterial taxa whose proportion in dental plaque exhibited significant variation by plaque urease levels in both visits were the family Pasteurellaceae (Baseline P<0.001; One Year P = 0.0148), especially Haemophilus parainfluenzae. No association was observed between these bacteria and dental caries. Bacteria in the genus Leptotrichia were negatively associated with urease and positively associated with dental caries (Bonferroni P<0.001). CONCLUSIONS Alkali production by urease enzymes primarily from species in the family Pasteurellaceae can be an important ecological determinant in children's dental plaque. Further studies are needed to establish the role of urease-associated bacteria in the acid/base homeostasis of the dental plaque, and in the development and prediction of dental caries in children.
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Affiliation(s)
- Diego Mora
- Department of Food Environmental and Nutritional Sciences, University of Milan, Milan, Italy
| | - Stefania Arioli
- Department of Food Environmental and Nutritional Sciences, University of Milan, Milan, Italy
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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: 111] [Impact Index Per Article: 9.3] [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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Urease activity represents an alternative pathway for Mycobacterium tuberculosis nitrogen metabolism. Infect Immun 2012; 80:2771-9. [PMID: 22645285 DOI: 10.1128/iai.06195-11] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Urease represents a critical virulence factor for some bacterial species through its alkalizing effect, which helps neutralize the acidic microenvironment of the pathogen. In addition, urease serves as a nitrogen source provider for bacterial growth. Pathogenic mycobacteria express a functional urease, but its role during infection has yet to be characterized. In this study, we constructed a urease-deficient Mycobacterium tuberculosis strain and confirmed the alkalizing effect of the urease activity within the mycobacterium-containing vacuole in resting macrophages but not in the more acidic phagolysosomal compartment of activated macrophages. However, the urease-mediated alkalizing effect did not confer any growth advantage on M. tuberculosis in macrophages, as evidenced by comparable growth profiles for the mutant, wild-type (WT), and complemented strains. In contrast, the urease-deficient mutant exhibited impaired in vitro growth compared to the WT and complemented strains when urea was the sole source of nitrogen. Substantial amounts of ammonia were produced by the WT and complemented strains, but not with the urease-deficient mutant, which represents the actual nitrogen source for mycobacterial growth. However, the urease-deficient mutant displayed parental colonization profiles in the lungs, spleen, and liver in mice. Together, our data demonstrate a role for the urease activity in M. tuberculosis nitrogen metabolism that could be crucial for the pathogen's survival in nutrient-limited microenvironments where urea is the sole nitrogen source. Our work supports the notion that M. tuberculosis virulence correlates with its unique metabolic versatility and ability to utilize virtually any carbon and nitrogen sources available in its environment.
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Morou-Bermudez E, Elias-Boneta A, Billings RJ, Burne RA, Garcia-Rivas V, Brignoni-Nazario V, Suarez-Perez E. Urease activity in dental plaque and saliva of children during a three-year study period and its relationship with other caries risk factors. Arch Oral Biol 2011; 56:1282-9. [PMID: 21616477 DOI: 10.1016/j.archoralbio.2011.04.015] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2010] [Revised: 03/19/2011] [Accepted: 04/28/2011] [Indexed: 11/30/2022]
Abstract
UNLABELLED Bacterial urease activity in dental plaque and in saliva generates ammonia, which can increase the plaque pH and can protect acid-sensitive oral bacteria. Recent cross-sectional studies suggest that reduced ability to generate ammonia from urea in dental plaque can be an important caries risk factor. In spite of this proposed important clinical role, there is currently no information available regarding important clinical aspects of oral ureolysis in children. OBJECTIVE The objective of this study was to evaluate the distribution and pattern of urease activity in the dental plaque and in the saliva of children during a three-year period, and to examine the relationship of urease with some important caries risk factors. METHODS A longitudinal study was conducted with repeated measures over a three-year period on a panel of 80 children, aged 3-6 years at recruitment. The dynamics of change in urease activity were described and associated with clinical, biological, and behavioural caries risk factors. RESULTS Urease activity in plaque showed a trend to remain stable during the study period and was negatively associated with sugar consumption (P<0.05). Urease activity in unstimulated saliva increased with age, and it was positively associated with the levels of mutans streptococci in saliva and with the educational level of the parents (P<0.05). CONCLUSIONS The results of this study reveal interesting and complex interactions between oral urease activity and some important caries risk factors. Urease activity in saliva could be an indicator of mutans infection in children.
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Affiliation(s)
- E Morou-Bermudez
- University of Puerto Rico, School of Dental Medicine, San Juan, Puerto Rico.
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Gupta S, Marwah N. 'Use a Thorn to Draw Thorn' Replacement Therapy for Prevention of Dental Caries. Int J Clin Pediatr Dent 2010; 3:125-37. [PMID: 27616834 PMCID: PMC4993818 DOI: 10.5005/jp-journals-10005-1068] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2010] [Accepted: 06/07/2010] [Indexed: 11/23/2022] Open
Abstract
Despite the use of conventional physical and chemotherapeutic agents for caries management, dental caries still continues to be the most prevalent oral infectious disease. Thus, there is a need of additional caries prevention approaches. Strain replacement therapy is one such novel approach. In this, relatively avirulent strains of Streptococcus mutans produced by recombinant DNA technology are implanted into the oral cavity. These may either interfere with the colonization of, or compete with the indigenous cariogenic mutans streptococci. This technique might provide a cost-effective, long-term means of achieving tailor made protection for the host against dental caries.
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Affiliation(s)
- Seema Gupta
- Senior Resident, Department of Pedodontics and Preventive Dentistry, Maulana Azad Institute of Dental Sciences, New Delhi, India
| | - Nikhil Marwah
- Reader, Department of Pediatric Dentistry, Mahatma Gandhi Dental College, Jaipur, Rajasthan, India
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Toro E, Nascimento MM, Suarez-Perez E, Burne RA, Elias-Boneta A, Morou-Bermudez E. The effect of sucrose on plaque and saliva urease levels in vivo. Arch Oral Biol 2010; 55:249-54. [PMID: 20096398 PMCID: PMC2853032 DOI: 10.1016/j.archoralbio.2009.12.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2009] [Revised: 12/07/2009] [Accepted: 12/28/2009] [Indexed: 10/19/2022]
Abstract
OBJECTIVE Dietary sugar exposures induce an immediate drop of the plaque pH. Based on in vitro observations, it was hypothesized that oral bacteria may rapidly respond to this environmental change by increasing the activity or expression of alkali-generating pathways, such as the urease pathway. The objective of this exploratory in vivo study was to determine the short-term effect of a brief sucrose exposure on plaque and saliva urease activity and expression, and to relate this effect to caries experience. METHODS Urease activity levels were measured in plaque and saliva samples collected from 20 children during fasting conditions and 30 min after rinsing with a sucrose solution. Streptococcus salivarius ureC-specific mRNA in saliva was quantified using real-time RT-PCR. The impact of host-related factors, such as age, gender, sugar consumption, salivary mutans streptococci levels and caries status on urease activity was evaluated. RESULTS Plaque urease activity under fasting conditions was higher in subjects with low caries and mutans streptococci levels. This difference was not observed after the sucrose exposure. The response of urease to sucrose in vivo did not depend on caries experience or salivary mutans levels. Significant increase in urease activity of plaque and saliva after exposure to sucrose was observed only in the subjects who had low urease levels at baseline. CONCLUSIONS The findings of this exploratory study suggest that plaque urease activity may have an important long-term influence in caries development but not during a cariogenic challenge.
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Affiliation(s)
- E Toro
- University of Puerto Rico, School of Dental Medicine, San Juan, Puerto Rico
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Barboza-Silva E, Castro ACD, Marquis RE. Fluoride, triclosan and organic weak acids as modulators of the arginine deiminase system in biofilms and suspension cells of oral streptococci. ACTA ACUST UNITED AC 2009; 24:265-71. [DOI: 10.1111/j.1399-302x.2008.00502.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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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: 131] [Impact Index Per Article: 8.7] [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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Liy Y, Yaling L, Dan J, Tao H, Xuedong Z. Regulation of urease expression of Actinomyces naeslundii in biofilms in response to pH and carbohydrate. ACTA ACUST UNITED AC 2008; 23:315-9. [PMID: 18582331 DOI: 10.1111/j.1399-302x.2008.00430.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
INTRODUCTION The hydrolysis of urea by the urease enzymes of oral bacteria is believed to have a major impact on oral microbial ecology and to be intimately involved in oral health and diseases. Actinomyces naeslundii is a ureolytic bacterium that is adapted to tolerate the rapid and dramatic fluctuations in nutrient availability, carbohydrate source, and pH in dental biofilms. Our research objectives were to better understand the regulation of the expression of urease under environmental conditions that closely mimic those in dental biofilms. METHODS A. naeslundii ATCC12104 were grown in a chemostat biofilm reactor with carbohydrate-limited medium for 3 days followed by a carbohydrate pulse, at pH 7.0 and at pH 5.5. Urease activities and ureC gene messenger RNA levels of cells in the biofilm were measured before and after the carbohydrate pulse. RESULTS We found that the neutral pH environments and excess carbohydrate availability could both result in enhancement of urease activity in biofilm cells. The ureC messenger RNA level of A. naeslundii biofilm cells cultivated at pH 7.0 was approximately 10-fold higher than that of cells grown at pH 5.5, but no changes in ureC gene expression were detected after the carbohydrate pulse. CONCLUSIONS Neutral pH environments and excess carbohydrate availability could promote urease expression of A. naeslundii in biofilms, but only neutral pH environments could up-regulate the ureC gene expression and the pH regulates ureC gene expression at a transcriptional level.
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Affiliation(s)
- Y Liy
- Department of Oral Biology, College of Dentistry, University of Florida, Gainesville, FL, USA.
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Kuramitsu HK, He X, Lux R, Anderson MH, Shi W. Interspecies interactions within oral microbial communities. Microbiol Mol Biol Rev 2007; 71:653-70. [PMID: 18063722 PMCID: PMC2168648 DOI: 10.1128/mmbr.00024-07] [Citation(s) in RCA: 373] [Impact Index Per Article: 21.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
While reductionism has greatly advanced microbiology in the past 400 years, assembly of smaller pieces just could not explain the whole! Modern microbiologists are learning "system thinking" and "holism." Such an approach is changing our understanding of microbial physiology and our ability to diagnose/treat microbial infections. This review uses oral microbial communities as a focal point to describe this new trend. With the common name "dental plaque," oral microbial communities are some of the most complex microbial floras in the human body, consisting of more than 700 different bacterial species. For a very long time, oral microbiologists endeavored to use reductionism to identify the key genes or key pathogens responsible for oral microbial pathogenesis. The limitations of reductionism forced scientists to begin adopting new strategies using emerging concepts such as interspecies interaction, microbial community, biofilms, polymicrobial disease, etc. These new research directions indicate that the whole is much more than the simple sum of its parts, since the interactions between different parts resulted in many new physiological functions which cannot be observed with individual components. This review describes some of these interesting interspecies-interaction scenarios.
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Affiliation(s)
- Howard K Kuramitsu
- Department of Oral Boiology, School of Dental Medicine, State University of New York, Buffalo, New York, USA
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Liu Y, Hu T, Jiang D, Zhang J, Zhou X. Regulation of urease gene of Actinomyces naeslundii in biofilms in response to environmental factors. FEMS Microbiol Lett 2007; 278:157-63. [PMID: 18034831 DOI: 10.1111/j.1574-6968.2007.00959.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
The metabolism of urea by urease enzymes of oral bacteria has a profound influence on oral biofilm pH homeostasis and oral microbial ecology, and Actinomyces naeslundii is an important ureolytic organism in the oral cavity. To gain an insight into the regulation of urease gene expression in cells of A. naeslundii growing in biofilms under different environmental conditions, the behavior of A. naeslundii ATCC12104 was examined in in vitro biofilms. The strain was grown in a chemostat biofilm reactor, and at a quasi-steady state, the urease activity of biofilm cells was measured and transcription of ureC gene was detected with Taqman quantitative PCR. The effect of environmental changes on urease expression was examined by varying the environmental pH, dilution rate, carbohydrate and nitrogen availability of the fluid phase of the culture. The results showed that the conditions of neutral pH, fast dilution rate, increased carbohydrate supply or low nitrogen supply in the medium all resulted in enhancement of urease activity in biofilm cells. But only low nitrogen availability and a fast dilution rate were observed to lead to an increase in ureC mRNA levels. This suggests that nitrogen availability and dilution rate can influence the urease activity of A. naeslundii by modulating ureC gene transcription.
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Moelling C, Oberschlacke R, Ward P, Karijolich J, Borisova K, Bjelos N, Bergeron L. Metal-dependent repression of siderophore and biofilm formation in Actinomyces naeslundii. FEMS Microbiol Lett 2007; 275:214-20. [PMID: 17825071 DOI: 10.1111/j.1574-6968.2007.00888.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Actinomyces naeslundii is a pioneer of the oral cavity and forms a biofilm on the tooth's surface. Most bacteria require iron for survival and in pathogenic bacteria iron availability regulates virulence gene expression. Metal-dependent repressors control gene expression involved in metal transport and uptake including siderophores. Siderophores are small molecules synthesized by bacteria and fungi to acquire iron. The A. naeslundii genome was searched for a gene encoding a metal-dependent repressor. Actinomyces metal-dependent repressor or amdR was identified. The AmdR protein was examined for its ability to bind to the promoter sequence of a gene encoding the siderophore uptake (sid gene). According to gel shift assays, AmdR binds to the sid gene promoter sequences. In the authors' model, when iron is available AmdR binds to the sid promoter and represses sid gene expression. To further explore the role of AmdR, an amdR-defective strain of A. naeslundii was constructed and biofilm formation and siderophore production were evaluated. When iron is removed from the medium A. naeslundii increases biofilm and siderophore production. However, amdR-defective A. naeslundii is less sensitive to metal ion concentrations in the growth medium.
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Affiliation(s)
- Cas Moelling
- Department of Biology, Ripon College, Ripon, WI, USA
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Brucella suis urease encoded by ure1 but not ure2 is necessary for intestinal infection of BALB/c mice. BMC Microbiol 2007; 7:57. [PMID: 17578575 PMCID: PMC1983905 DOI: 10.1186/1471-2180-7-57] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2006] [Accepted: 06/19/2007] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND In prokaryotes, the ureases are multi-subunit, nickel-containing enzymes that catalyze the hydrolysis of urea to carbon dioxide and ammonia. The Brucella genomes contain two urease operons designated as ure1 and ure2. We investigated the role of the two Brucella suis urease operons on the infection, intracellular persistence, growth, and resistance to low-pH killing. RESULTS The deduced amino acid sequence of urease-alpha subunits of operons-1 and -2 exhibited substantial identity with the structural ureases of alpha- and beta-proteobacteria, Gram-positive and Gram-negative bacteria, fungi, and higher plants. Four ure deficient strains were generated by deleting one or more of the genes encoding urease subunits of B. suis strain 1330 by allelic exchange: strain 1330Deltaure1K (generated by deleting ureD and ureA in ure1 operon), strain 1330Deltaure2K (ureB and ureC in ure2 operon), strain 1330Deltaure2C (ureA, ureB, and ureC in ure2 operon), and strain 1330Deltaure1KDeltaure2C (ureD and ureA in ure1 operon and ureA, ureB, and ureC in ure2 operon). When grown in urease test broth, strains 1330, 1330Deltaure2K and 1330Deltaure2C displayed maximal urease enzyme activity within 24 hours, whereas, strains 1330Deltaure1K and 1330Deltaure1KDeltaure2C exhibited zero urease activity even 96 h after inoculation. Strains 1330Deltaure1K and 1330Deltaure1KDeltaure2C exhibited slower growth rates in tryptic soy broth relative to the wild type strain 1330. When the BALB/c mice were infected intraperitoneally with the strains, six weeks after inoculation, the splenic recovery of the ure deficient strains did not differ from the wild type. In contrast, when the mice were inoculated by gavage, one week after inoculation, strain 1330Deltaure1KDeltaure2C was cleared from livers and spleens while the wild type strain 1330 was still present. All B. suis strains were killed when they were incubated in-vitro at pH 2.0. When the strains were incubated at pH 2.0 supplemented with 10 mM urea, strain 1330Deltaure1K was completely killed, strain 1330Deltaure2C was partially killed, but strains 1330 and 1330Deltaure2K were not killed. CONCLUSION These findings suggest that the ure1 operon is necessary for optimal growth in culture, urease activity, resistance against low-pH killing, and in vivo persistence of B. suis when inoculated by gavage. The ure2 operon apparently enhances the resistance to low-pH killing in-vitro.
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Barboza-Silva E, Castro ACD, Marquis RE. Mechanisms of inhibition by fluoride of urease activities of cell suspensions and biofilms of Staphylococcus epidermidis, Streptococcus salivarius, Actinomyces naeslundii and of dental plaque. ACTA ACUST UNITED AC 2005; 20:323-32. [PMID: 16238590 DOI: 10.1111/j.1399-302x.2005.00228.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
BACKGROUND/AIMS Fluoride is known to be a potent inhibitor of bacterial ureases and can also act in the form of hydrofluoric acid as a transmembrane proton conductor to acidify the cytoplasm of intact cells with possible indirect, acid inhibition of urease. Our research objectives were to assess the inhibitory potencies of fluoride for three urease-positive bacteria commonly found in the mouth and to determine the relative importance of direct and indirect inhibition of ureases for overall inhibition of intact cells or biofilms. METHODS The experimental design involved intact bacteria in suspensions, mono-organism biofilms, cell extracts, and dental plaque. Standard enzymatic assays for ammonia production from urea were used. RESULTS We found that ureolysis by cells in suspensions or mono-organism biofilms of Staphylococcus epidermidis, Streptococcus salivarius or Actinomyces naeslundii was inhibited by fluoride at plaque levels of 0.1-0.5 mm in a pH-dependent manner. The results of experiments with the organic weak acids indomethacin and capric acid, which do not directly inhibit urease enzyme, indicated that weak-acid effects leading to cytoplasmic acidification are also involved in fluoride inhibition. However, direct fluoride inhibition of urease appeared to be the major mechanism for reduction in ureolytic activity in acid environments. Results of experiments with freshly harvested supragingival dental plaque indicated responses to fluoride similar to those of S. salivarius with pH-dependent fluoride inhibition and both direct and indirect inhibition of urease. CONCLUSION Fluoride can act to diminish alkali production from urea by oral bacteria through direct and indirect mechanisms.
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Affiliation(s)
- E Barboza-Silva
- Department of Microbiology & Immunology, University of Rochester Medical Center, Rochester, NY 14642-8672, USA
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Shu M, Browngardt CM, Chen YYM, Burne RA. Role of urease enzymes in stability of a 10-species oral biofilm consortium cultivated in a constant-depth film fermenter. Infect Immun 2004; 71:7188-92. [PMID: 14638814 PMCID: PMC308945 DOI: 10.1128/iai.71.12.7188-7192.2003] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Using a 10-species oral biofilm consortium and defined mutants, we show that high-level capacity to generate ammonia from a common salivary substrate is needed to maintain community diversity. This model appears to be suitable for the study of the effects of individual genetic determinants on the ecology of oral biofilms.
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Affiliation(s)
- Man Shu
- Department of Oral Biology, University of Florida College of Dentistry, Gainesville, Florida 32610-0424, USA
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30
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Puskás LG, Inui M, Yukawa H. Structure of the urease operon of Corynebacterium glutamicum. DNA SEQUENCE : THE JOURNAL OF DNA SEQUENCING AND MAPPING 2001; 11:383-94, 467. [PMID: 11328647 DOI: 10.3109/10425170009033989] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Urease activity of Corynebacterium glutamicum results in a rapid pH increase upon addition of urea to the growth medium. The urease operon C. glutamicum was isolated of and sequenced. Seven open reading frames were identified; ureA, ureB, and ureC were homologues of other bacterial urease structural genes, ureE, ureF, ureG, and ureD exhibited homology to urease accessory genes. Disruption of ureC prevented the utilization of urea as a nitrogen source by C. glutamicum. Urease activity was induced by urea and appeared to be independent of the nitrogen regulatory system. Urease activity was not affected by pH. Heterologous expression of a truncated derivative of the urease gene cluster in Escherichia coli showed that ureD was necessary for active expression. Western-blot and primer extension analysis on C. glutamicum grown under different conditions confirmed that the operon was induced by urea. Transcriptional startpoint for the ureA gene was determined.
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Affiliation(s)
- L G Puskás
- Research Institute of Innovative Technology for the Earth (RITE), Kyoto, Japan
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31
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Guggenheim M, Shapiro S, Gmür R, Guggenheim B. Spatial arrangements and associative behavior of species in an in vitro oral biofilm model. Appl Environ Microbiol 2001; 67:1343-50. [PMID: 11229930 PMCID: PMC92733 DOI: 10.1128/aem.67.3.1343-1350.2001] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The spatial arrangements and associative behavior of Actinomyces naeslundii, Veillonella dispar, Fusobacterium nucleatum, Streptococcus sobrinus, and Streptococcus oralis strains in an in vitro model of supragingival plaque were determined. Using species-specific fluorescence-labeled antibodies in conjunction with confocal laser scanning microscopy, the volumes and distribution of the five strains were assessed during biofilm formation. The volume-derived cell numbers of each strain correlated well with respective culture data. Between 15 min and 64 h, populations of each strain increased in a manner reminiscent of batch growth. The microcolony morphologies of all members of the consortium and their distributions within the biofilm were characterized, as were interspecies associations. Biofilms formed 15 min after inoculation consisted principally of single nonaggregated cells. All five strains adhered strongly to the saliva-conditioned substratum, and therefore, coadhesion played no role during the initial phase of biofilm formation. This observation does not reflect the results of in vitro coaggregation of the five strains, which depended upon the nature of the suspension medium. While the possibility cannot be excluded that some interspecies associations observed at later stages of biofilm formation were initiated by coadhesion, increase in bacterial numbers appeared to be largely a growth phenomenon regulated by the prevailing cultivation conditions.
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Affiliation(s)
- M Guggenheim
- Institute for Oral Microbiology and General Immunology, Center for Dental and Oral Medicine and Maxillofacial Surgery, University of Zürich, CH-8028 Zürich, Switzerland
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32
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Morou-Bermudez E, Burne RA. Analysis of urease expression in Actinomyces naeslundii WVU45. Infect Immun 2000; 68:6670-6. [PMID: 11083780 PMCID: PMC97765 DOI: 10.1128/iai.68.12.6670-6676.2000] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2000] [Accepted: 09/13/2000] [Indexed: 11/20/2022] Open
Abstract
The hydrolysis of urea by ureases of oral bacteria in dental plaque can cause a considerable increase in plaque pH, which can inhibit the development of dental caries. There is also indirect evidence that urea metabolism may promote the formation of calculus and that ammonia release from urea could exacerbate periodontal diseases. Actinomyces naeslundii, an early colonizer of the oral cavity and a numerically significant plaque constituent, demonstrates comparatively low levels of urease activity on isolation, so this organism has not been considered a major contributor to total oral urease activity. In this study it was observed that urease activity and urease-specific mRNA levels in A. naeslundii WVU45 can increase up to 50-fold during growth under nitrogen-limiting conditions. Using primer extension analysis, a putative, proximal, nitrogen-regulated promoter of the A. naeslundii urease gene cluster was identified. The functionality and nitrogen responsiveness of this promoter were confirmed using reporter gene fusions and 5' deletion analysis. The data indicated that regulation of urease expression by nitrogen availability in A. naeslundii may require a positive transcriptional activator. Plaque bacteria may experience nitrogen limitation when carbohydrates are present in excess. Therefore, based on the results of this study and in contrast to previous beliefs, strains of A. naeslundii may have the potential to be significant contributors to total plaque ureolysis, particularly during periods when there is an increased risk for caries development.
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Affiliation(s)
- E Morou-Bermudez
- Center for Oral Biology and Department of Microbiology and Immunology, University of Rochester School of Medicine and Dentistry, Rochester, New York 14642, USA
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33
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Abstract
pH is a key environmental factor affecting the physiology, ecology and pathogenicity of the oral biofilms colonizing the hard tissues of the human mouth. Much attention has been focused on the production of organic acids through the metabolism of carbohydrates by pathogenic oral bacteria. Now, evidence is emerging that alkali generation, particularly through ammonia production from arginine and urea, plays major roles in pH homeostasis in oral biofilms and may moderate initiation and progression of dental caries. This short review highlights recent progress on understanding molecular genetic and physiologic aspects of ammonia generation by prominent oral bacteria.
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Affiliation(s)
- R A Burne
- Center for Oral Biology and Department of Microbiology and Immunology, University of Rochester Medical Center, Box 611, 601 Elmwood Ave., Rochester, NY 14642, USA.
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34
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Sissons CH, Yakub S. Suppression of urease levels in Streptococcus salivarius by cysteine, related compounds and by sulfide. ORAL MICROBIOLOGY AND IMMUNOLOGY 2000; 15:317-24. [PMID: 11154424 DOI: 10.1034/j.1399-302x.2000.150509.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Urease synthesis in Streptococcus salivarius is induced by an acid environment, carbohydrate and a high growth rate. We now report that both cysteine and sulfide above 1 mM strongly suppress S. salivarius urease levels. Close structural relatives of cysteine (cysteamine, ethanedithiol and penicillamine) at 5 mM buffered to pH 7.0 also caused urease suppression, but thiols in general (2-mercaptoethanol, dithiothreitol and glutathione) did not. In cultures buffered below pH 5.9, the cysteine-induced urease suppression was lifted substantially, but the sulfide suppression increased, suggesting involvement of different processes. Urease activity was inhibited 50% by 5 mM mercaptoethanol but unaffected by 5 mM cysteine or sulfide, hence modification of enzyme activity by thiols is not directly related to suppression of their levels in culture. Cysteine, arising primarily through protein hydrolysis which also raises the pH, could be a surrogate pH feedback signal for nearby alkaline conditions, and sulfide may reflect activity of periodontopathic plaques.
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Affiliation(s)
- C H Sissons
- Dental Research Group, Department of Pathology, Wellington School of Medicine, P.O. Box 7343, Wellington South, New Zealand
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35
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Bossé JT, MacInnes JI. Urease activity may contribute to the ability of Actinobacillus pleuropneumoniae to establish infection. CANADIAN JOURNAL OF VETERINARY RESEARCH = REVUE CANADIENNE DE RECHERCHE VETERINAIRE 2000; 64:145-50. [PMID: 10935879 PMCID: PMC1189605] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/17/2023]
Abstract
The contribution of urease activity to the pathogenesis of Actinobacillus pleuropneumoniae was investigated using 2 different urease-negative transposon mutants of the virulent serotype 1 strain, CM5 Nalr. One mutant, cbiK::Tn10, is deficient in the uptake of nickel, a cofactor required for urease activity. The other mutant, ureG::Tn10, is unable to produce active urease due to mutation of the urease accessory gene, ureG. In aerosol challenge experiments, pigs developed acute pleuropneumonia following exposure to high doses (10(6) cfu/mL) of the parental strain, CM5 Nalr, and to the cbiK::Tn10 mutant. When low dose (10(3) cfu/mL) challenges were used, neither urease-negative mutant was able to establish infection, whereas the parental strain was able to colonize and cause lesions consistent with acute pleuropneumonia in 8 of the 20 pigs challenged. These findings suggest that urease activity may be needed for A. pleuropneumoniae to establish infection in the respiratory tract of pigs.
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Affiliation(s)
- J T Bossé
- Department of Pathobiology, University of Guelph, Ontario
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36
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Bergeron LJ, Morou-Bermudez E, Burne RA. Characterization of the fructosyltransferase gene of Actinomyces naeslundii WVU45. J Bacteriol 2000; 182:3649-54. [PMID: 10850978 PMCID: PMC94534 DOI: 10.1128/jb.182.13.3649-3654.2000] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Oral actinomycetes produce fructosyltransferase (FTF) enzymes which convert sucrose into polymers of D-fructose, known as levans, and these polymers are thought to contribute to the persistence and virulence of the organisms. A gene encoding FTF was isolated from Actinomyces naeslundii WVU45; the deduced amino acid sequence showed significant similarity to known levansucrases of gram-negative environmental isolates but was less similar to FTFs from gram-positive bacteria. A transcriptional start site was mapped by primer extension 70 bp 5' from the putative start codon. Promoter fusions to a chloramphenicol acetyltransferase gene were used to confirm that there was a functional promoter driving ftf expression and to show that sequences located 86 to 218 bp upstream of the transcription initiation site were required for optimal ftf expression. Quantitative slot blot analysis against total RNA from cells grown on different sugars or from different growth phases revealed that ftf was constitutively transcribed. Thus, the A. naeslundii FTF is more similar in primary sequence and the regulation of expression to levansucrases of gram-negative bacteria than gram-positive bacteria.
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Affiliation(s)
- L J Bergeron
- Center for Oral Biology, Department of Microbiology and Immunology, University of Rochester School of Medicine and Dentistry, Rochester, New York 14642, USA
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37
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Clancy KA, Pearson S, Bowen WH, Burne RA. Characterization of recombinant, ureolytic Streptococcus mutans demonstrates an inverse relationship between dental plaque ureolytic capacity and cariogenicity. Infect Immun 2000; 68:2621-9. [PMID: 10768953 PMCID: PMC97468 DOI: 10.1128/iai.68.5.2621-2629.2000] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Dental caries results from prolonged plaque acidification that leads to the establishment of a cariogenic microflora and demineralization of the tooth. Urease enzymes of oral bacteria hydrolyze urea to ammonia, which can neutralize plaque acids. To begin to examine the relationship between plaque ureolytic activity and the incidence of dental caries, recombinant, ureolytic strains of Streptococcus mutans were constructed. Specifically, the ureABCEFGD operon from Streptococcus salivarius 57.I was integrated into the S. mutans chromosome in such a way that the operon was transcribed from a weak, cognate promoter in S. mutans ACUS4 or a stronger promoter in S. mutans ACUS6. Both strains expressed NiCl(2)-dependent urease activity, but the maximal urease levels in ACUS6 were threefold higher than those in ACUS4. In vitro pH drop experiments demonstrated that the ability of the recombinant S. mutans strains to moderate a decrease in pH during the simultaneous metabolism of glucose and urea increased proportionately with the level of urease activity expressed. Specific-pathogen-free rats that were infected with ACUS6 and fed a cariogenic diet with drinking water containing 25 mM urea and 50 microM NiCl(2) had relatively high levels of oral urease activity, as well as dramatic decreases in the prevalence of smooth-surface caries and the severity of sulcal caries, relative to controls. Urease activity appears to influence plaque biochemistry and metabolism in a manner that reduces cariogenicity, suggesting that recombinant, ureolytic bacteria may be useful to promote dental health.
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Affiliation(s)
- K A Clancy
- Department of Microbiology and Immunology and Center for Oral Biology, University of Rochester Medical Center, Rochester, New York 14642, USA
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38
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Yeung MK. Molecular and genetic analyses of Actinomyces spp. CRITICAL REVIEWS IN ORAL BIOLOGY AND MEDICINE : AN OFFICIAL PUBLICATION OF THE AMERICAN ASSOCIATION OF ORAL BIOLOGISTS 2000; 10:120-38. [PMID: 10759417 DOI: 10.1177/10454411990100020101] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Members of the genus Actinomyces are predominant primary colonizers of the oral cavity and play an important role in initiating plaque development. These bacteria have evolved unique mechanisms that favor colonization and persistence in this micro-environment. The expression of cell-surface fimbriae is correlated with the ability of these bacteria to adhere to specific receptors on the tooth and mucosal surfaces, and to interact with other plaque bacteria. The elaboration of sialidase is thought to enhance fimbriae-mediated adherence by unmasking the fimbrial receptors on mammalian cells. The presence of certain cell-associated or extracellular enzymes, including those involved in sucrose or urea metabolism, may provide the means for these bacteria to thrive under conditions when other growth nutrients are not available. Moreover, these enzyme activities may influence the distribution of other plaque bacteria and promote selection for Actinomyces spp. in certain ecological niches. The recent development of a genetic transfer system for Actinomyces spp. has allowed for studies the results of which demonstrate the existence of multiple genes involved in fimbriae synthesis and function, and facilitated the construction of allelic replacement mutants at each gene locus. Analyses of these mutants have revealed a direct correlation between the synthesis of assembled fimbriae and the observed adherence properties. Further genetic analysis of the various enzyme activities detected from strains of Actinomyces should allow for an assessment of the role of these components in microbial ecology, and their contribution to the overall success of Actinomyces spp. as a primary colonizer and a key player in oral health and disease.
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Affiliation(s)
- M K Yeung
- Department of Pediatric Dentistry, University of Texas Health Science Center at San Antonio, 78284, USA
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Abstract
Ureases are multi-subunit, nickel-containing enzymes that catalyze the hydrolysis of urea to carbon dioxide and ammonia. This brief review discusses the biochemistry and genetics of bacterial ureases and outlines the roles of urea metabolism in microbial ecology and pathogenesis of some of the principle ureolytic species affecting human health.
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Affiliation(s)
- R A Burne
- Department of Microbiology and Immunology, Center for Oral Biology, University of Rochester School of Medicine and Dentistry, 601 Elmwood Ave, Rochester, NY, USA
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40
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Shu M, Wong L, Miller JH, Sissons CH. Development of multi-species consortia biofilms of oral bacteria as an enamel and root caries model system. Arch Oral Biol 2000; 45:27-40. [PMID: 10669090 DOI: 10.1016/s0003-9969(99)00111-9] [Citation(s) in RCA: 77] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
The aim was to establish defined-species consortium plaque biofilms to investigate enamel and root caries in an artificial mouth. Strains of the putative enamel and root caries pathogens, Streptococcus mutans, Strep. sobrinus, Actinomyces naeslundii and Lactobacillus rhamnosus, were screened in batch culture for potential cariogenic properties: a low terminal pH, ability to aggregate, and catabolic diversity. The strains selected were grown as monoculture biofilms and as consortium plaque biofilms in a multiplaque artificial mouth. The biofilms were supplied with a constant flow of a simulated oral fluid and were given periodic sucrose (and in some instances glucose) to simulate meals. All the bacteria except L. rhamnosus formed large, monospecies biofilms with resting pH in the range 5.3-5.8. The consortia biofilms were larger and had a resting pH of 4.9-5.3. The consortia biofilms supplied with 8-hourly carbohydrate comprised mainly 'mutans' streptococci (58, SD 5.5%) and L. rhamnosus (42, SD 5.7%). A. naeslundii characteristically was absent or present in a low percentage (up to 4% colony-forming units). All biofilms demineralized polished bovine enamel and dentine blocks, as assessed by microradiography and enamel-surface microhardness measurement. The consortia also demineralized intact enamel and tooth roots; they were more cariogenic to enamel than any of the monoculture biofilms, as measured by enamel-surface softening, but variation in lesion depth was proportional to biofilm wet weight irrespective of acidogen composition (r = 0.93, p < 0.05). Enamel lesions had a well-mineralized intact surface and a zone of subsurface demineralization, typical of early natural lesions. Dentine and root lesions showed extensive demineralization but lacked a pronounced surface mineralized zone. Substitution of glucose for sucrose had no effect on the cariogenicity of the consortium to bovine enamel or human roots and had no major effect on the plaque composition. Continuously supplied fluoride (19 parts/10(6)) resulted in a substantially reduced enamel surface softening and subsurface demineralization of intact roots. It was concluded that consortia biofilms of selected caries pathogens generate realistic caries lesions in all tooth hard tissues under controlled growth conditions in the artificial mouth. This in vitro caries experimental model may prove useful for the study of interrelations between the plaque biofilm, tooth tissues and the oral environment, and for the development of procedures to modify the course of caries development.
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Affiliation(s)
- M Shu
- Department of Pathology and Molecular Medicine, Wellington School of Medicine, University of Otago, New Zealand
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