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Abstract
The oral bacterial microbiome encompasses approximately 700 commonly occurring phylotypes, approximately half of which can be present at any time in any individual. These bacteria are largely indigenous to the oral cavity; this limited habitat range suggests that interactions between the various phylotypes, and between the phylotypes and their environment, are crucial for their existence. Molecular cataloging has confirmed many basic observations on the composition of the oral microbiome that were formulated well before ribosomal RNA-based systematics, but the power and the scope of molecular taxonomy have resulted in the discovery of new phylotypes and, more importantly, have made possible a level of bacterial community analysis that was unachievable with classical methods. Bacterial community structure varies with location within the mouth, and changes in community structure are related to disease initiation and disease progression. Factors that influence the formation and the evolution of communities include selective adherence to epithelial or tooth surfaces, specific cell-to-cell binding as a driver of early community composition, and interorganismal interaction leading to alteration of the local environment, which represents the first step on the road to oral disease. A comprehensive understanding of how these factors interact to drive changes in the composition of the oral microbial community can lead to new strategies for the inhibition of periodontal diseases and dental caries.
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Naß B, Pöll U, Langer JD, Kreuter L, Küper U, Flechsler J, Heimerl T, Rachel R, Huber H, Kletzin A. Three multihaem cytochromes c from the hyperthermophilic archaeon Ignicoccus hospitalis: purification, properties and localization. MICROBIOLOGY-SGM 2014; 160:1278-1289. [PMID: 24705227 DOI: 10.1099/mic.0.077792-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Three different multihaem cytochromes c were purified from cell extracts of the hyperthermophilic archaeon Ignicoccus hospitalis. One tetrahaem cytochrome, locus tag designation Igni_0530, was purified from membrane fractions together with the iron-sulfur protein Igni_0529. Two octahaem cytochromes, Igni_0955 and Igni_1359, were purified from soluble fractions but were also present in the membrane fraction. N-terminal sequencing showed that three of the four proteins had their signal peptides cleaved off, while results were ambiguous for Igni_0955. In contrast, mass spectrometry of Igni_0955 and Igni_1359 resulted in single mass peaks including the signal sequences and eight haems per subunit and so both forms might be present in the cell. Igni_0955 and Igni_1359 belong to the hydroxylamine dehydrogenase (HAO) family (29 % mutual identity). HAO or reductase activities with inorganic sulfur compounds were not detected. Igni_0955 was reduced by enriched I. hospitalis hydrogenase at a specific activity of 243 nmol min(-1) (mg hydrogenase)(-1) while activity was non-existent for Igni_0530 and low for Igni_1359. Immuno-electron microscopy of ultra-thin sections showed that Igni_0955 and Igni_1359 are located in both I. hospitalis membranes and also in the intermembrane compartment. We concluded that these cytochromes might function as electron shuttles between the hydrogenase in the outer cellular membrane and cellular reductases, whereas Igni_0530 might be part of the sulfur-reducing mechanism.
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Affiliation(s)
- Bastian Naß
- Technische Universität Darmstadt, Microbiology - Sulfur Biochemistry and Microbial Bioenergetics, Darmstadt, Germany
| | - Uwe Pöll
- Technische Universität Darmstadt, Microbiology - Sulfur Biochemistry and Microbial Bioenergetics, Darmstadt, Germany
| | - Julian David Langer
- Max Planck Institute of Biophysics, Max-von-Laue-Straße 3, 60438 Frankfurt am Main, Germany
| | - Lydia Kreuter
- Lehrstuhl für Mikrobiologie, Universität Regensburg, Universitätsstraße 31, 93053 Regensburg, Germany
| | - Ulf Küper
- Lehrstuhl für Mikrobiologie, Universität Regensburg, Universitätsstraße 31, 93053 Regensburg, Germany
| | - Jennifer Flechsler
- Zentrum für Elektronenmikroskopie, Universität Regensburg, Universitätsstraße 31, 93053 Regensburg, Germany
| | - Thomas Heimerl
- Zentrum für Elektronenmikroskopie, Universität Regensburg, Universitätsstraße 31, 93053 Regensburg, Germany
| | - Reinhard Rachel
- Zentrum für Elektronenmikroskopie, Universität Regensburg, Universitätsstraße 31, 93053 Regensburg, Germany
| | - Harald Huber
- Lehrstuhl für Mikrobiologie, Universität Regensburg, Universitätsstraße 31, 93053 Regensburg, Germany
| | - Arnulf Kletzin
- Technische Universität Darmstadt, Microbiology - Sulfur Biochemistry and Microbial Bioenergetics, Darmstadt, Germany
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Hethke C, Bergerat A, Hausner W, Forterre P, Thomm M. Cell-free transcription at 95 degrees: thermostability of transcriptional components and DNA topology requirements of Pyrococcus transcription. Genetics 1999; 152:1325-33. [PMID: 10430563 PMCID: PMC1460703 DOI: 10.1093/genetics/152.4.1325] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Cell-free transcription of archaeal promoters is mediated by two archaeal transcription factors, aTBP and TFB, which are orthologues of the eukaryotic transcription factors TBP and TFIIB. Using the cell-free transcription system described for the hyperthermophilic Archaeon Pyrococcus furiosus by Hethke et al., the temperature limits and template topology requirements of archaeal transcription were investigated. aTBP activity was not affected after incubation for 1 hr at 100 degrees. In contrast, the half-life of RNA polymerase activity was 23 min and that of TFB activity was 3 min. The half-life of a 328-nt RNA product was 10 min at 100 degrees. Best stability of RNA was observed at pH 6, at 400 mm K-glutamate in the absence of Mg(2+) ions. Physiological concentrations of K-glutamate were found to stabilize protein components in addition, indicating that salt is an important extrinsic factor contributing to thermostability. Both RNA and proteins were stabilized by the osmolyte betaine at a concentration of 1 m. The highest activity for RNA synthesis at 95 degrees was obtained in the presence of 1 m betaine and 400 mm K-glutamate. Positively supercoiled DNA, which was found to exist in Pyrococcus cells, can be transcribed in vitro both at 70 degrees and 90 degrees. However, negatively supercoiled DNA was the preferred template at all temperatures tested. Analyses of transcripts from plasmid topoisomers harboring the glutamate dehydrogenase promoter and of transcription reactions conducted in the presence of reverse gyrase indicate that positive supercoiling of DNA inhibits transcription from this promoter.
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MESH Headings
- Archaeal Proteins/metabolism
- Cell-Free System
- DNA Topoisomerases, Type I
- DNA Topoisomerases, Type II/metabolism
- DNA, Archaeal/chemistry
- DNA, Archaeal/genetics
- DNA, Superhelical/chemistry
- DNA, Superhelical/genetics
- DNA-Directed RNA Polymerases/metabolism
- Gene Expression Regulation, Archaeal
- Half-Life
- Hot Temperature
- Nucleic Acid Conformation
- Protein Denaturation
- Pyrococcus furiosus/genetics
- Pyrococcus furiosus/physiology
- RNA, Archaeal/biosynthesis
- RNA, Archaeal/chemistry
- RNA, Archaeal/genetics
- RNA, Messenger/biosynthesis
- RNA, Messenger/chemistry
- RNA, Messenger/genetics
- Transcription, Genetic
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Affiliation(s)
- C Hethke
- Institut für Allgemeine Mikrobiologie, Universität Kiel, D-24118 Kiel, Germany
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Holst O, Manelius Å, Krahe M, Märkl H, Raven N, Sharp R. Thermophiles and fermentation technology. ACTA ACUST UNITED AC 1997. [DOI: 10.1016/s0300-9629(97)00002-9] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Segerer AH, Burggraf S, Fiala G, Huber G, Huber R, Pley U, Stetter KO. Life in hot springs and hydrothermal vents. ORIGINS LIFE EVOL B 1993; 23:77-90. [PMID: 11536528 DOI: 10.1007/bf01581992] [Citation(s) in RCA: 69] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Hot springs and hydrothermal systems occurring within volcanic areas are inhabited by hyperthermophilic microorganisms, some of which grow at temperatures up to 110 degrees C. Hyperthermophiles grow anaerobically or aerobically by diverse metabolic types. Within the high temperature ecosystems, primary production is independent from solar energy.
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Affiliation(s)
- A H Segerer
- Lehrstuhl fur Mikrobiologie, Universitat Regensburg, Federal Republic of Germany
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Isolation and Characterization of Three Thermophilic Anaerobes from a St. Lucia Hot Spring. Syst Appl Microbiol 1992. [DOI: 10.1016/s0723-2020(11)80104-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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McCabe A. The potential significance of microbial activity in radioactive waste disposal. ACTA ACUST UNITED AC 1990. [DOI: 10.1007/bf01935524] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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10
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Effect of carbon dioxide and hydrostatic pressure on the pH of culture media and the growth of methanogens at elevated temperature. Appl Microbiol Biotechnol 1988. [DOI: 10.1007/bf00694308] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Pyrobaculum gen. nov., a new genus of neutrophilic, rod-shaped archaebacteria from continental solfataras growing optimally at 100�C. Arch Microbiol 1987. [DOI: 10.1007/bf00425072] [Citation(s) in RCA: 71] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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