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Hassani II, Quadri I, Yadav A, Bouchard S, Raoult D, Hacène H, Desnues C. Assessment of diversity of archaeal communities in Algerian chott. Extremophiles 2023; 27:2. [PMID: 36469177 DOI: 10.1007/s00792-022-01287-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Accepted: 11/23/2022] [Indexed: 12/12/2022]
Abstract
Halophilic archaea are the dominant type of microorganisms in hypersaline environments. The diversity of halophilic archaea in Zehrez-Chergui (Saharian chott) was analyzed and compared by both analysis of a library of PCR amplified 16S rRNA genes and by cultivation approach. This work, represents the first of its type in Algeria. A total cell count was estimated at 3.8 × 103 CFU/g. The morphological, biochemical, and physiological characterizations of 45 distinct strains, suggests that all of them might be members of the class Halobacteria. Among stains, 23 were characterized phylogenetically and are related to 6 genera of halophilic archaea.The dominance of the genus Halopiger, has not been reported yet in other hypersaline environments. The 100 clones obtained by the molecular approach, were sequenced, and analyzed. The ribosomal library of 61 OTUs showed that the archaeal diversity included uncultured haloarcheon, Halomicrobium, Natronomonas, Halomicroarcula, Halapricum, Haloarcula, Halosimplex, Haloterrigena, Halolamina, Halorubellus, Halorussus and Halonotius. The results of rarefaction analysis indicated that the analysis of an increasing number of clones would have revealed additional diversity. Surprisingly, no halophilic archaea were not shared between the two approaches. Combining both types of methods was considered the best approach to acquire better information on the characteristics of soil halophilic archaea.
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Affiliation(s)
- Imene Ikram Hassani
- Laboratoire de Biologie Cellulaire et Moléculaire, Faculté de Biologie, USTHB Université, Bab Ezzouar, Algeria.
| | - Inès Quadri
- Laboratoire de Biologie Cellulaire et Moléculaire, Faculté de Biologie, USTHB Université, Bab Ezzouar, Algeria
| | - Archana Yadav
- Department of Microbiology and Molecular Genetics, Oklahoma State University, Stillwater, Oklahoma, USA
| | - Sonia Bouchard
- Faculté de Médecine, Aix-Marseille Université, URMITE, UM63, CNRS7278, IRD 198, Inserm U1095, 27 Boulevard Jean Moulin, 13385, Marseille, France
| | - Didier Raoult
- Faculté de Médecine, Aix-Marseille Université, URMITE, UM63, CNRS7278, IRD 198, Inserm U1095, 27 Boulevard Jean Moulin, 13385, Marseille, France
| | - Hocine Hacène
- Laboratoire de Biologie Cellulaire et Moléculaire, Faculté de Biologie, USTHB Université, Bab Ezzouar, Algeria
| | - Christelle Desnues
- Faculté de Médecine, Aix-Marseille Université, URMITE, UM63, CNRS7278, IRD 198, Inserm U1095, 27 Boulevard Jean Moulin, 13385, Marseille, France
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Tirumalai MR, Anane-Bediakoh D, Rajesh S, Fox GE. Net Charges of the Ribosomal Proteins of the S10 and spc Clusters of Halophiles Are Inversely Related to the Degree of Halotolerance. Microbiol Spectr 2021; 9:e0178221. [PMID: 34908470 PMCID: PMC8672879 DOI: 10.1128/spectrum.01782-21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Accepted: 11/24/2021] [Indexed: 11/20/2022] Open
Abstract
Net positive charge(s) on ribosomal proteins (r-proteins) have been reported to influence the assembly and folding of ribosomes. A high percentage of r-proteins from extremely halophilic archaea are known to be acidic or even negatively charged. Those proteins that remain positively charged are typically far less positively charged. Here, the analysis is extended to non-archaeal halophilic bacteria, eukaryotes, and halotolerant archaea. The net charges (pH 7.4) of the r-proteins that comprise the S10-spc operon/cluster from individual microbial and eukaryotic genomes were estimated and intercompared. It was observed that, as a general rule, the net charges of individual proteins remained mostly basic as the salt tolerance of the bacterial strains increased from 5 to 15%. The most striking exceptions were the extremely halophilic bacterial strains, Salinibacter ruber SD01, Acetohalobium arabaticum DSM 5501 and Selenihalanaerobacter shriftii ATCC BAA-73, which are reported to require a minimum of 18% to 21% salt for their growth. All three strains have higher numbers of acidic S10-spc cluster r-proteins than what is seen in the moderate halophiles or the halotolerant strains. Of the individual proteins, only uL2 never became acidic. uS14 and uL16 also seldom became acidic. The net negative charges on several of the S10-spc cluster r-proteins are a feature generally shared by all extremely halophilic archaea and bacteria. The S10-spc cluster r-proteins of halophilic fungi and algae (eukaryotes) were exceptions: these were positively charged despite the halophilicity of the organisms. IMPORTANCE The net charges (at pH 7.4) of the ribosomal proteins (r-proteins) that comprise the S10-spc cluster show an inverse relationship with the halophilicity/halotolerance levels in both bacteria and archaea. In non-halophilic bacteria, the S10-spc cluster r-proteins are generally basic (positively charged), while the rest of the proteomes in these strains are generally acidic. On the other hand, the whole proteomes of the extremely halophilic strains are overall negatively charged, including the S10-spc cluster r-proteins. Given that the distribution of charged residues in the ribosome exit tunnel influences cotranslational folding, the contrasting charges observed in the S10-spc cluster r-proteins have potential implications for the rate of passage of these proteins through the ribosomal exit tunnel. Furthermore, the universal protein uL2, which lies in the oldest part of the ribosome, is always positively charged irrespective of the strain/organism it belongs to. This has implications for its role in the prebiotic context.
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Affiliation(s)
- Madhan R. Tirumalai
- Department of Biology and Biochemistry, University of Houston, Houston, Texas, USA
| | | | - Sidharth Rajesh
- Clements High School (Class of 2023), Fort Bend Independent School District, Sugar Land, Texas, USA
| | - George E. Fox
- Department of Biology and Biochemistry, University of Houston, Houston, Texas, USA
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Sorokin DY, Yakimov MM, Messina E, Merkel AY, Koenen M, Bale NJ, Sinninghe Damsté JS. Halapricum desulfuricans sp. nov., carbohydrate-utilizing, sulfur-respiring haloarchaea from hypersaline lakes. Syst Appl Microbiol 2021; 44:126249. [PMID: 34547593 DOI: 10.1016/j.syapm.2021.126249] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2021] [Revised: 08/27/2021] [Accepted: 08/29/2021] [Indexed: 11/19/2022]
Abstract
Nine pure cultures of neutrophilic haloaloarchaea capable of anaerobic growth by carbohydrate-dependent sulfur respiration were isolated from hypersaline lakes in southwestern Siberia and southern Russia. According to phylogenomic analysis the isolates were closely related to each other and formed a new species within the genus Halapricum (family Haloarculaceae). They have three types of catabolism: fermentative, resulting in H2 formation; anaerobic respiration using sulfur compounds as e-acceptors and aerobic respiration. Apart from elemental sulfur, all isolates can also use three different sulfoxides as acceptors and the type strain also grows with thiosulfate, reducing it partially to sulfide and sulfite. All strains utilized sugars and glycerol as the e-donors and C source for anaerobic growth and some can also grow with alpha-glucans, such as starch and dextrins. The major respiratory menaquinones are MK-8:8 and MK-8:7, but 5-19% consists of "thermoplasmata" quinones (MMK-8:8 and MMK-8:7), whose occurrence in haloarchaea is unprecedented. On the basis of their unique physiological properties and results of phylogenomic analysis, the isolates are suggested to be classified into a novel species Halapricum desulfuricans sp. nov. (type strain HSR12-2T = JCM 34032T = UNIQEM U1001T).
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Affiliation(s)
- Dimitry Y Sorokin
- Winogradsky Institute of Microbiology, Research Centre of Biotechnology, Russian Academy of Sciences, Moscow, Russia; Department of Biotechnology, Section of Environmental Biotechnology, TU Delft, The Netherlands.
| | | | - Enzo Messina
- IAMC-CNR, Spianata S.Raineri 86, 98122 Messina, Italy
| | - Alexander Y Merkel
- Winogradsky Institute of Microbiology, Research Centre of Biotechnology, Russian Academy of Sciences, Moscow, Russia
| | - Michel Koenen
- NIOZ Royal Netherlands Institute for Sea Research, Department of Marine Microbiology and Biogeochemistry, and Utrecht University, PO Box 59, 1790 AB Den Burg, Texel, The Netherlands
| | - Nicole J Bale
- NIOZ Royal Netherlands Institute for Sea Research, Department of Marine Microbiology and Biogeochemistry, and Utrecht University, PO Box 59, 1790 AB Den Burg, Texel, The Netherlands
| | - Jaap S Sinninghe Damsté
- NIOZ Royal Netherlands Institute for Sea Research, Department of Marine Microbiology and Biogeochemistry, and Utrecht University, PO Box 59, 1790 AB Den Burg, Texel, The Netherlands; Faculty of Geosciences, Department of Earth Sciences, Utrecht University, Utrecht, The Netherlands
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4
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Abstract
The large ribosomal RNAs of eukaryotes frequently contain expansion sequences that add to the size of the rRNAs but do not affect their overall structural layout and are compatible with major ribosomal function as an mRNA translation machine. The expansion of prokaryotic ribosomal RNAs is much less explored. In order to obtain more insight into the structural variability of these conserved molecules, we herein report the results of a comprehensive search for the expansion sequences in prokaryotic 5S rRNAs. Overall, 89 expanded 5S rRNAs of 15 structural types were identified in 15 archaeal and 36 bacterial genomes. Expansion segments ranging in length from 13 to 109 residues were found to be distributed among 17 insertion sites. The strains harboring the expanded 5S rRNAs belong to the bacterial orders Clostridiales, Halanaerobiales, Thermoanaerobacterales, and Alteromonadales as well as the archael order Halobacterales When several copies of a 5S rRNA gene are present in a genome, the expanded versions may coexist with normal 5S rRNA genes. The insertion sequences are typically capable of forming extended helices, which do not seemingly interfere with folding of the conserved core. The expanded 5S rRNAs have largely been overlooked in 5S rRNA databases.
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MESH Headings
- Alteromonadaceae/classification
- Alteromonadaceae/genetics
- Alteromonadaceae/metabolism
- Base Pairing
- Base Sequence
- Clostridiales/classification
- Clostridiales/genetics
- Clostridiales/metabolism
- Firmicutes/classification
- Firmicutes/genetics
- Firmicutes/metabolism
- Genome, Archaeal
- Genome, Bacterial
- Halobacteriales/classification
- Halobacteriales/genetics
- Halobacteriales/metabolism
- Nucleic Acid Conformation
- Phylogeny
- RNA, Archaeal/chemistry
- RNA, Archaeal/genetics
- RNA, Archaeal/metabolism
- RNA, Bacterial/chemistry
- RNA, Bacterial/genetics
- RNA, Bacterial/metabolism
- RNA, Ribosomal, 5S/chemistry
- RNA, Ribosomal, 5S/genetics
- RNA, Ribosomal, 5S/metabolism
- Thermoanaerobacterium/classification
- Thermoanaerobacterium/genetics
- Thermoanaerobacterium/metabolism
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Affiliation(s)
- Victor G Stepanov
- Department of Biology and Biochemistry, University of Houston, Houston, Texas 77204-5001, USA
| | - George E Fox
- Department of Biology and Biochemistry, University of Houston, Houston, Texas 77204-5001, USA
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5
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Montalvo-Rodríguez R, Maupin-Furlow JA. Insights through Genetics of Halophilic Microorganisms and Their Viruses. Genes (Basel) 2020; 11:genes11040388. [PMID: 32252451 PMCID: PMC7230515 DOI: 10.3390/genes11040388] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Accepted: 04/01/2020] [Indexed: 12/14/2022] Open
Abstract
Halophilic microorganisms are found in all domains of life and thrive in hypersaline (high salt content) environments. These unusual microbes have been a subject of study for many years due to their interesting properties and physiology. Study of the genetics of halophilic microorganisms (from gene expression and regulation to genomics) has provided understanding into mechanisms of how life can occur at high salinity levels. Here we highlight recent studies that advance knowledge of biological function through study of the genetics of halophilic microorganisms and their viruses.
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Affiliation(s)
- Rafael Montalvo-Rodríguez
- Department of Biology, University of Puerto Rico, Box 9000, Mayagüez, PR 00681, USA
- Correspondence: (R.M.-R.); (J.A.M.-F.)
| | - Julie A. Maupin-Furlow
- Department of Microbiology and Cell Science, Institute of Food and Agricultural Sciences, University of Florida, Gainesville, FL 32611, USA
- Correspondence: (R.M.-R.); (J.A.M.-F.)
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6
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Tafer H, Poyntner C, Lopandic K, Sterflinger K, Piñar G. Back to the Salt Mines: Genome and Transcriptome Comparisons of the Halophilic Fungus Aspergillus salisburgensis and Its Halotolerant Relative Aspergillus sclerotialis. Genes (Basel) 2019; 10:genes10050381. [PMID: 31137536 PMCID: PMC6563132 DOI: 10.3390/genes10050381] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2019] [Revised: 05/15/2019] [Accepted: 05/15/2019] [Indexed: 12/22/2022] Open
Abstract
Salt mines are among the most extreme environments as they combine darkness, low nutrient availability, and hypersaline conditions. Based on comparative genomics and transcriptomics, we describe in this work the adaptive strategies of the true halophilic fungus Aspergillus salisburgensis, found in a salt mine in Austria, and compare this strain to the ex-type halotolerant fungal strain Aspergillus sclerotialis. On a genomic level, A. salisburgensis exhibits a reduced genome size compared to A. sclerotialis, as well as a contraction of genes involved in transport processes. The proteome of A. sclerotialis exhibits an increased proportion of alanine, glycine, and proline compared to the proteome of non-halophilic species. Transcriptome analyses of both strains growing at 5% and 20% NaCl show that A. salisburgensis regulates three-times fewer genes than A. sclerotialis in order to adapt to the higher salt concentration. In A. sclerotialis, the increased osmotic stress impacted processes related to translation, transcription, transport, and energy. In contrast, membrane-related and lignolytic proteins were significantly affected in A. salisburgensis.
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Affiliation(s)
- Hakim Tafer
- VIBT EQ Extremophile Center, Department of Biotechnology, University of Natural Resources and Life Sciences, Muthgasse 18, 1190 Vienna, Austria.
| | - Caroline Poyntner
- VIBT EQ Extremophile Center, Department of Biotechnology, University of Natural Resources and Life Sciences, Muthgasse 18, 1190 Vienna, Austria.
| | - Ksenija Lopandic
- VIBT EQ Extremophile Center, Department of Biotechnology, University of Natural Resources and Life Sciences, Muthgasse 18, 1190 Vienna, Austria.
| | - Katja Sterflinger
- VIBT EQ Extremophile Center, Department of Biotechnology, University of Natural Resources and Life Sciences, Muthgasse 18, 1190 Vienna, Austria.
| | - Guadalupe Piñar
- VIBT EQ Extremophile Center, Department of Biotechnology, University of Natural Resources and Life Sciences, Muthgasse 18, 1190 Vienna, Austria.
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7
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Shen T, Zhang Z, Chen Z, Gu D, Liang S, Xu Y, Li R, Wei Y, Liu Z, Yi Y, Xie X. A genome-scale metabolic network alignment method within a hypergraph-based framework using a rotational tensor-vector product. Sci Rep 2018; 8:16376. [PMID: 30401914 PMCID: PMC6219566 DOI: 10.1038/s41598-018-34692-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2018] [Accepted: 10/23/2018] [Indexed: 12/14/2022] Open
Abstract
Biological network alignment aims to discover important similarities and differences and thus find a mapping between topological and/or functional components of different biological molecular networks. Then, the mapped components can be considered to correspond to both their places in the network topology and their biological attributes. Development and evolution of biological network alignment methods has been accelerated by the rapidly increasing availability of such biological networks, yielding a repertoire of tens of methods based upon graph theory. However, most biological processes, especially the metabolic reactions, are more sophisticated than simple pairwise interactions and contain three or more participating components. Such multi-lateral relations are not captured by graphs, and computational methods to overcome this limitation are currently lacking. This paper introduces hypergraphs and association hypergraphs to describe metabolic networks and their potential alignments, respectively. Within this framework, metabolic networks are aligned by identifying the maximal Z-eigenvalue of a symmetric tensor. A shifted higher-order power method was utilized to identify a solution. A rotational strategy has been introduced to accelerate the tensor-vector product by 250-fold on average and reduce the storage cost by up to 1,000-fold. The algorithm was implemented on a spark-based distributed computation cluster to significantly increase the convergence rate further by 50- to 80-fold. The parameters have been explored to understand their impact on alignment accuracy and speed. In particular, the influence of initial value selection on the stationary point has been simulated to ensure an accurate approximation of the global optimum. This framework was demonstrated by alignments among the genome-wide metabolic networks of Escherichia coli MG-1655 and Halophilic archaeon DL31. To our knowledge, this is the first genome-wide metabolic network alignment at both the metabolite level and the enzyme level. These results demonstrate that it can supply quite a few valuable insights into metabolic networks. First, this method can access the driving force of organic reactions through the chemical evolution of metabolic network. Second, this method can incorporate the chemical information of enzymes and structural changes of compounds to offer new way defining reaction class and module, such as those in KEGG. Third, as a vertex-focused treatment, this method can supply novel structural and functional annotation for ill-defined molecules. The related source code is available on request.
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Affiliation(s)
- Tie Shen
- Key Laboratory of Information and Computing Science Guizhou Province, Guizhou Normal University, Guiyang, Guizhou, China.
| | - Zhengdong Zhang
- College of Mathematics and Information Science, Guiyang University, Guiyang, Guizhou, China
| | - Zhen Chen
- College of Mathematical Science, Guizhou Normal University, Guiyang, Guizhou, China
| | - Dagang Gu
- College of Mathematics and Information Science, Guiyang University, Guiyang, Guizhou, China
| | - Shen Liang
- College of Mathematics and Information Science, Guiyang University, Guiyang, Guizhou, China
| | - Yang Xu
- Key Laboratory of Information and Computing Science Guizhou Province, Guizhou Normal University, Guiyang, Guizhou, China
| | - Ruiyuan Li
- Key Laboratory of Information and Computing Science Guizhou Province, Guizhou Normal University, Guiyang, Guizhou, China
| | - Yimin Wei
- School of Mathematics Sciences and Key Laboratory of Mathematics for Nonlinear Sciences, Fudan University, Shanghai, China
| | - Zhijie Liu
- Key Laboratory of Information and Computing Science Guizhou Province, Guizhou Normal University, Guiyang, Guizhou, China
| | - Yin Yi
- Key Laboratory of State Forestry Administration on Biodiversity Conservation in Karst of Southwest Areas China, Guizhou Normal University, Guiyang, Guizhou, China.
| | - Xiaoyao Xie
- Key Laboratory of Information and Computing Science Guizhou Province, Guizhou Normal University, Guiyang, Guizhou, China.
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Gómez-Villegas P, Vigara J, León R. Characterization of the Microbial Population Inhabiting a Solar Saltern Pond of the Odiel Marshlands (SW Spain). Mar Drugs 2018; 16:md16090332. [PMID: 30213145 PMCID: PMC6164061 DOI: 10.3390/md16090332] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2018] [Revised: 08/28/2018] [Accepted: 09/08/2018] [Indexed: 12/11/2022] Open
Abstract
The solar salterns located in the Odiel marshlands, in southwest Spain, are an excellent example of a hypersaline environment inhabited by microbial populations specialized in thriving under conditions of high salinity, which remains poorly explored. Traditional culture-dependent taxonomic studies have usually under-estimated the biodiversity in saline environments due to the difficulties that many of these species have to grow at laboratory conditions. Here we compare two molecular methods to profile the microbial population present in the Odiel saltern hypersaline water ponds (33% salinity). On the one hand, the construction and characterization of two clone PCR amplified-16S rRNA libraries, and on the other, a high throughput 16S rRNA sequencing approach based on the Illumina MiSeq platform. The results reveal that both methods are comparable for the estimation of major genera, although massive sequencing provides more information about the less abundant ones. The obtained data indicate that Salinibacter ruber is the most abundant genus, followed by the archaea genera, Halorubrum and Haloquadratum. However, more than 100 additional species can be detected by Next Generation Sequencing (NGS). In addition, a preliminary study to test the biotechnological applications of this microbial population, based on its ability to produce and excrete haloenzymes, is shown.
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Affiliation(s)
- Patricia Gómez-Villegas
- Laboratory of Biochemistry and Molecular Biology, Faculty of Experimental Sciences, Marine International Campus of Excellence (CEIMAR), University of Huelva, 21071 Huelva, Spain.
| | - Javier Vigara
- Laboratory of Biochemistry and Molecular Biology, Faculty of Experimental Sciences, Marine International Campus of Excellence (CEIMAR), University of Huelva, 21071 Huelva, Spain.
| | - Rosa León
- Laboratory of Biochemistry and Molecular Biology, Faculty of Experimental Sciences, Marine International Campus of Excellence (CEIMAR), University of Huelva, 21071 Huelva, Spain.
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9
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Kurt-Kızıldoğan A, Abanoz B, Okay S. Global transcriptome analysis of Halolamina sp. to decipher the salt tolerance in extremely halophilic archaea. Gene 2016; 601:56-64. [PMID: 27919704 DOI: 10.1016/j.gene.2016.11.042] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2016] [Revised: 11/17/2016] [Accepted: 11/30/2016] [Indexed: 12/21/2022]
Abstract
Extremely halophilic archaea survive in the hypersaline environments such as salt lakes or salt mines. Therefore, these microorganisms are good sources to investigate the molecular mechanisms underlying the tolerance to high salt concentrations. In this study, a global transcriptome analysis was conducted in an extremely halophilic archaeon, Halolamina sp. YKT1, isolated from a salt mine in Turkey. A comparative RNA-seq analysis was performed using YKT1 isolate grown either at 2.7M NaCl or 5.5M NaCl concentrations. A total of 2149 genes were predicted to be up-regulated and 1638 genes were down-regulated in the presence of 5.5M NaCl. The salt tolerance of Halolamina sp. YKT1 involves the up-regulation of genes related with membrane transporters, CRISPR-Cas systems, osmoprotectant solutes, oxidative stress proteins, and iron metabolism. On the other hand, the genes encoding the proteins involved in DNA replication, transcription, translation, mismatch and nucleotide excision repair were down-regulated. The RNA-seq data were verified for seven up-regulated genes as well as six down-regulated genes via qRT-PCR analysis. This comprehensive transcriptome analysis showed that the halophilic archaeon canalizes its energy towards keeping the intracellular osmotic balance minimizing the production of nucleic acids and peptides.
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Affiliation(s)
- Aslıhan Kurt-Kızıldoğan
- Department of Agricultural Biotechnology, Faculty of Agriculture, Ondokuz Mayıs University, 55139 Samsun, Turkey
| | - Büşra Abanoz
- Department of Agricultural Biotechnology, Faculty of Agriculture, Ondokuz Mayıs University, 55139 Samsun, Turkey
| | - Sezer Okay
- Department of Biology, Faculty of Science, Çankırı Karatekin University, 18100 Çankırı, Turkey.
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10
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Ozcan B, Ozyilmaz G, Cihan A, Cokmus C, Caliskan M. Phylogenetic analysis and characterization of lipolytic activity of halophilic archaeal isolates. Mikrobiologiia 2012; 81:205-213. [PMID: 22693829] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Five isolates designated as B45, D83A, A206A, A85 and E49 and found to possess a activity were taxonomically classified on the basis of their phylogenetic, phenotypic and chemotaxonomic characteristics. The isolates were determined to be Gram-negative, catalase and oxidase positive, hydrolyzing Tween 80 and 60 but not starch, need 3.5-4 M NaCl for optimal growth and lack of anaerobic growth with arginine or DMSO. All isolates had the highest lipolytic activity at pH 8.5. Lipase and esterase activities increased with salt concentration up to 3-4.5 M NaCl, and decreased at 5 M NaCl. Esterase and lipase showed their maximal activities at 50-55 degrees C and 60-65 degrees C, respectively. The phylogenetic tree constructed by the neighbor-joining method indicated that the strain B45 and A85 were closely related to the members of genera Halovivax and Natrinema, respectively. The closest relative of the strain A206A and D83A were found to be Haloterrigena saccharevitans. The strain E49 displayed a more distant relationship to known strains.
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Affiliation(s)
- B Ozcan
- Mustafa Kemal University, Biology Department, Faculty of Sciences and Letters, Turkey.
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11
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Luque R, González-Domenech CM, Llamas I, Quesada E, Béjar V. Diversity of culturable halophilic archaea isolated from Rambla Salada, Murcia (Spain). Extremophiles 2012; 16:205-13. [PMID: 22219037 DOI: 10.1007/s00792-011-0420-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2011] [Accepted: 12/13/2011] [Indexed: 11/26/2022]
Abstract
We have studied the diversity of culturable halophilic Archaea at Rambla Salada, Murcia (south-eastern Spain). We made 8 samplings at different places in this habitat during the years 2006 and 2007 and isolated a total of 49 strains, which were identified by means of phenotypic tests and the hypervariable V1-V3 region of the 16S rRNA gene sequences (around 500 bp). The ribosomal data showed that the isolates belonged to 12 genera within the Halobacteriaceae family, with Haloferax and Natrinema being the most abundant. Five strains showed less than 97% sequence identity with validly described species and may well represent new taxa. All the strains grew best with around 25% w/v salts, required high concentrations of NaCl and magnesium and produced red to pink colonies. They were facultative anaerobes with both respiratory and fermentative metabolisms. The diversity of the archaeal community was analysed with the MOTHUR package. We identified 14 OTUs at the 3% genetic distance level and found quite high diversity. Rarefaction curves of richness estimators and diversity indices demonstrated that our collection of isolates represented the archaeal community at Rambla Salada that can be isolated under the conditions used in this work. This is the first report to be published on the culturable archaea at Rambla Salada, an area of considerable ecological interest.
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Affiliation(s)
- R Luque
- Department of Microbiology, Faculty of Pharmacy, University of Granada, Granada, Spain
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12
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Yildiz E, Ozcan B, Caliskan M. Isolation, characterization and phylogenetic analysis of halophilic archaea from a salt mine in central Anatolia (Turkey). Pol J Microbiol 2012; 61:111-117. [PMID: 23163210] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/01/2023] Open
Abstract
The haloarchaeal diversity of a salt mine, a natural cave in central Anatolia, was investigated using convential microbiological and molecular biology methods. Eight halophilic archaeal isolates selected based on their colony morphology and whole cell protein profiles were taxonomically classified on the basis of their morphological, physiological, biochemical properties, polar lipid and protein profiles and 16S rDNA sequences. From the 16S rDNA sequences comparisons it was established that the isolates CH2, CH3 and CHC resembled Halorubrum saccharovorum by 98.8%, 98.9% and 99.5%, respectively. There was a 99.7% similarity between the isolate CH11 and Halobacterium noricense and 99.2% between the isolate CHA1 and Haloarcula argentinensis. The isolate CH8K and CH8B revealed a similarity rate of 99.8% and 99.3% to Halococcus dombrowskii, respectively. It was concluded that the isolates named CH2, CH3 and CHC were clustered in the genus Halorubrum and that CHA1 and CH7 in the genus Haloarcula, CH8K and CH8B in the genus Halococcus and CH11 in the genus Halobacterium.
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Affiliation(s)
- Evrim Yildiz
- Mustafa Kemal University, Biology Department, 31040 Hatay, Turkey
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Liu B, Tang S, Ming H, He S, Nie G, Guan T, Zhang L, Li W. [Biodiversity and functional enzymes of cultured halophilic archaeon in Lop Nur region]. Wei Sheng Wu Xue Bao 2011; 51:1222-1231. [PMID: 22126078] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
OBJECTIVE In order to explore the diversity of cultured halophilic archaeon from hypersaline environments in Lop Nur region and their potential application. METHODS Total 13 soil samples were collected from Lop Nur regions. Halophilic archaea strains were isolated and identified by 16S rRNA gene sequence analysis. In addition, 17 strains were selected based on different branches in pylogenetic tree, and their salt concentration tolerance and amylase, protease, esterase activities were further detected by conventional methods. RESULTS The 16S rRNA gene sequences of 56 selected strains were determined, and the phylogenetic analysis was carried out. These strains were classified into 10 known genera and 5 new potential genera, and the Shannon index was 1.820. The range of salt concentration tolerance of most strains was 10% - 35% (optimum at 20% - 25%). Amylase positive rate was 70.6%, protease positive rate was 35.3% and esterase positive rate was 82.4%. CONCLUSION Diverse halophilic archaeon were discovered in Lop Nur regions. The isolation methods that we used were successful for isolating halophilic archaeon from these areas, which provided the technical basis to future explore the resources of halophilic archaeon in Lop Nur regions.
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Affiliation(s)
- Bingbing Liu
- Key Laboratory of Protection and Utilization of Biological Resources in Tarim Basin of Xinjiang Corps, College of Life Science, Tarim University, Alar 843300, China.
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Mavromatis K, Ivanova N, Anderson I, Lykidis A, Hooper SD, Sun H, Kunin V, Lapidus A, Hugenholtz P, Patel B, Kyrpides NC. Genome analysis of the anaerobic thermohalophilic bacterium Halothermothrix orenii. PLoS One 2009; 4:e4192. [PMID: 19145256 PMCID: PMC2626281 DOI: 10.1371/journal.pone.0004192] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2008] [Accepted: 12/04/2008] [Indexed: 11/19/2022] Open
Abstract
Halothermothirx orenii is a strictly anaerobic thermohalophilic bacterium isolated from sediment of a Tunisian salt lake. It belongs to the order Halanaerobiales in the phylum Firmicutes. The complete sequence revealed that the genome consists of one circular chromosome of 2578146 bps encoding 2451 predicted genes. This is the first genome sequence of an organism belonging to the Haloanaerobiales. Features of both Gram positive and Gram negative bacteria were identified with the presence of both a sporulating mechanism typical of Firmicutes and a characteristic Gram negative lipopolysaccharide being the most prominent. Protein sequence analyses and metabolic reconstruction reveal a unique combination of strategies for thermophilic and halophilic adaptation. H. orenii can serve as a model organism for the study of the evolution of the Gram negative phenotype as well as the adaptation under thermohalophilic conditions and the development of biotechnological applications under conditions that require high temperatures and high salt concentrations.
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Abstract
Solar salterns operate only for short dry periods of the year in the north shore of the Adriatic Sea because of its relatively humid and cold Mediterranean climate. In a previous paper, we showed that the NaCl precipitation ponds (crystallizers) of Northern Adriatic Secovlje salterns have different haloarchaeal populations from those typically found in dry and hot climates such as Southern Spain. To check whether there is a common pattern of haloarchaeal diversity in these less extreme conditions, diversity in crystallizers of other Adriatic solar salterns in Ston, Croatia was ascertained by molecular and culture methods. In addition, the cultivation approach was used to further describe haloarchaeal diversity in both salterns. Over the period of two solar salt collection seasons, isolates related to species of the genera Haloferax, Haloarcula, and Haloterrigena were recovered from both salterns. Within the same sampling effort, relatives of the genus Halorubrum and a Natrinema-like isolate were cultivated from Slovenian Secovlje salterns while Halobacterium related isolates were obtained from the Croatian Ston salterns. Concurrent with our previous findings, a library of Croatian saltern crystallizer PCR-amplified 16S rRNA genes was dominated by sequences related to the genus Halorubrum. The microbial community structure was similar in both salterns but diversity indices showed greater values in Slovenian salterns when compared with Croatian salterns.
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Affiliation(s)
- Lejla Pasić
- Department of Biology, Biotechnical Faculty, University of Ljubljana, Slovenia.
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Abstract
In prokaryotes the twin-arginine translocase (Tat) is a unique transport system for the export of folded proteins. The Tat pathway is usually involved in the export of a small proportion of extracytoplasmic proteins. An exception is found in halophilic archaea, in which the majority of secretory proteins have been predicted to be Tat-dependent. All haloarchaea analysed to date contain two genes encoding homologues of the Tat-component TatC. In all of these cases both genes are located adjacently on the chromosome, indicating that they form a functional unit. We show that this gene cluster is essential for viability in haloarchaea, which is in complete contrast to all other prokaryotes that have been tested thus far.
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Affiliation(s)
- Judith R Thomas
- University of Warwick, Department of Biological Sciences, Coventry, UK
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Xu XH, Wu M, Zhang HB, Liu ZH. Genetic analysis of the br gene in halophilic archaea isolated from Xinjiang region. Hereditas 2007; 29:376-80. [PMID: 17369163 DOI: 10.1360/yc-007-0376] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Some novel members of extremely halophilic Archaea, strain AJ11, AJ12 and AJ13, were isolated from Aularz Lake located in Altun Mountain National Nature Reserve of Xinjiang Uygur Autonomous Region in China. Partial DNA fragments encoding a bacteriorhodopsin (BR) as well as for 16S rRNA of isolated strains were amplified by PCR and their DNA sequences were determined subsequently. On the basis of homology and phylogenetic analysis about 16S rDNA, it was considered that the isolated strains formed a microbiological population are the members of genus Natrinema. The results of genetic analysis, such as GC content, transition/transversion (Ti/Tv) rate ratios, synonymous substitution rates (Ks), indicated that the br fragments with high level of genetic divergence are faced with both purifying selection and bias mutation pressure. The study provides the base for using of species and BR proteins resources.
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Affiliation(s)
- Xiao-Hong Xu
- Ningbo Institute of Technology, Zhejiang University, Ningbo, China.
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Iro M, Klein R, Gálos B, Baranyi U, Rössler N, Witte A. The lysogenic region of virus φCh1: identification of a repressor-operator system and determination of its activity in halophilic Archaea. Extremophiles 2006; 11:383-96. [PMID: 17123129 DOI: 10.1007/s00792-006-0040-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2006] [Accepted: 10/09/2006] [Indexed: 11/25/2022]
Abstract
phiCh1 is a temperate virus infecting the haloalkaliphilic archaeon Natrialba magadii. As for all temperate viruses, a control of the lysogenic state versus the lytic life cycle is essential. Two open reading frames (ORFs) have been identified as putative repressor encoding genes: ORF48 and ORF49. The protein of ORF48 showed sequence similarities to putative repressor molecules. ORF49 was identified by the analysis of a mutant of phiCh1: the lysogenic strain carrying mutant phiCh1-1 showed a different lysis behavior than wild type virus phiCh1, indicating a dysfunction in the regulation of gene expression. Here, we show that the intergenic region between ORF48 and ORF49 comprises a promoter/operator sequence that is a transcriptionally active region in the model system Haloferax volcanii. Transcription from this region can be repressed by the activity of the ORF48 gene product. Gp43/gp44 has an enhancing effect on this regulatory sequence. Evidence is given for a possible binding site of Rep and gp43/gp44 within the coding region of the rep gene.
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Affiliation(s)
- M Iro
- Department of Microbiology and Immunobiology, Max F. Perutz Laboratories, University of Vienna, Dr. Bohr-Gasse 9, Vienna, 1030, Austria
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19
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Abstract
Phylogenetic relationships within the halophilic archaea were inferred from comparisons of the 16S rRNA gene sequences from 61 strains, representing 18 genera with validly published names within the orderHalobacteriales. Trees produced using distance-matrix (least-squares and neighbour-joining) methods affirm with strong bootstrap support that the members of the orderHalobacterialesare a monophyletic group. Ten genera were supported as monophyletic groups [Haloarcula,Halobiforma,Halococcus,Haloferax,Halorubrum,Halosimplex(multiple sequences from a single strain),Natrialba,Natrinema,NatronococcusandNatronorubrum] and eight genera were represented by a single strain (Halobacterium,Halobaculum,Halogeometricum,Halomicrobium,Halorhabdus,Halosimplex,NatronobacteriumandNatronomonas). The genusHaloterrigenawas always paraphyletic, and the phylogenetic placement of and sister groups toHalobacteriumandNatronomonascould not be resolved. Both treeing methods failed to resolve the deep branching patterns within the orderHalobacterialesand the relationships between the major clades. Additional representation from the currently monospecific genera and/or the use of other macromolecules may be required to resolve the relationships within the orderHalobacteriales.
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Affiliation(s)
- André-Denis Girard Wright
- CSIRO Livestock Industries, Centre for Environment and Life Sciences, Private Bag 5, Wembley, Western Australia 6913, Australia
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Pan HL, Zhou C, Wang HL, Xue YF, Ma YH. [Diversity of halophilic archaea in hypersaline lakes of Inner Mongolia, China]. Wei Sheng Wu Xue Bao 2006; 46:1-6. [PMID: 16579455] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
The aims of this work were to explore the diversity of halophilic archaea in hypersaline lakes of Inner Mongolia, China and to collect novel halophilic archaea. One hundred and sixty-five halophilic archaea were isolated from the three different types of hypersaline lakes (Erliannor, shangmatala and Xilin soda lake) in Inner Mongolia. By analysis of the restriction patterns of amplified 16S rDNA (ARDRA) with the enzyme Afa I and Hae II, respectively, the isolates were clustered into 14 genotypes, and the representatives of each genotype were randomly chosen for the determination of 16S rDNA sequence. The phylogenetic analysis revealed that all of the isolates were clustered into 10 groups: Halorubrum, Natronococcus, Natronorubrum, Haloterrigena, Halorhabdus, Halobiforma, Haloarcula, Haloferax and other two unknown groups. Dominant isolates were related to Halorubrum spp. in all three lakes. Some of the isolates studied showed less affiliation with known taxa ( <98% sequence similarity) and may represent novel taxa. Two isolates HXH33 and HSH33 showed very less affiliation with known genus ( < 93% sequence similarity) and may represent two new genera. These results suggest that diverse archaea exist in and the unknown archaea thrive in the hypersaline lakes of Inner Mongolia.
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Affiliation(s)
- Hai-Lian Pan
- Institute of Microbiology, Chinese Academy of Sciences, Beijing 100080, China.
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Xu XW, Liu SJ, Tohty D, Oren A, Wu M, Zhou PJ. Haloterrigena saccharevitans sp. nov., an extremely halophilic archaeon from Xin-Jiang, China. Int J Syst Evol Microbiol 2005; 55:2539-2542. [PMID: 16280523 DOI: 10.1099/ijs.0.63761-0] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
A novel extremely halophilic strain, isolated from Aibi salt lake, Xin-Jiang, China, was subjected to polyphasic taxonomic characterization. This strain, designated AB14T, is neutrophilic, motile and requires at least 10 % (w/v) NaCl for growth. Strain AB14T grows at 24–58 °C, with optimal growth at 42–45 °C. Mg2+ is not required, but growth is observed in MgCl2 concentrations as high as 1·0 M. Strain AB14T possesses the diphytanyl (C20C20) and phytanyl-sesterterpanyl diether (C20C25) derivatives of phosphatidylglycerol, phosphatidylglycerol phosphate methyl ester and mannose-2,6 disulfate 1→2 glucose-glycerol diether. The genomic DNA G+C content is 66·6 mol%. The 16S rRNA gene sequence similarity values of strain AB14T with its nearest phylogenetic neighbours (Haloterrigena thermotolerans and Haloterrigena turkmenica) are 98·6 and 96·0 %, respectively. DNA–DNA hybridization revealed 54 % relatedness between strain AB14T and Haloterrigena thermotolerans JCM 11050T and 21 % between strain AB14T and Haloterrigena turkmenica JCM 9101T. It is therefore proposed that strain AB14T represents a novel species, for which the name Haloterrigena saccharevitans sp. nov. is proposed. The type strain is AB14T (=AS 1.3730T=JCM 12889T).
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Affiliation(s)
- Xue-Wei Xu
- Institute of Microbiology, Chinese Academy of Sciences, ZhongGuanCun, Haidian, Beijing 100080, P. R. China
- College of Life Sciences, Zhejiang University, Hangzhou 310027, P. R. China
| | - Shuang-Jiang Liu
- Institute of Microbiology, Chinese Academy of Sciences, ZhongGuanCun, Haidian, Beijing 100080, P. R. China
| | - Dilbar Tohty
- Department of Biology, Xinjiang Normal University, Urumqi 830054, P. R. China
| | - Aharon Oren
- Institute of Life Sciences and the Moshe Shilo Minerva Center for Marine Biogeochemistry, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Min Wu
- College of Life Sciences, Zhejiang University, Hangzhou 310027, P. R. China
| | - Pei-Jin Zhou
- Institute of Microbiology, Chinese Academy of Sciences, ZhongGuanCun, Haidian, Beijing 100080, P. R. China
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Takaki Y, Matsuki A, Chee GJ, Takami H. Identification and distribution of new insertion sequences in the genome of the extremely halotolerant and alkaliphilic Oceanobacillus iheyensis HTE831. DNA Res 2005; 11:233-45. [PMID: 15500249 DOI: 10.1093/dnares/11.4.233] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Six kinds of new insertion sequences (ISs), IS667 to IS672, a group II intron (Oi.Int), and an incomplete transposon (Tn852loi) were identified in the 3,630,528-bp genome of the extremely halotolerant and alkaliphilic Oceanobacillus iheyensis HTE831. Of 19 ISs identified in the HTE831 genome, 7 were truncated, indicating the occurrence of internal rearrangement of the genome. All ISs except IS669 generated a 4- to 8-bp duplication of the target site sequence, and these ISs carried 23- to 28-bp inverted repeats (IRs). Sequence analysis revealed that four ISs (IS669, IS670, IS671, and IS672) were newly identified as belonging to separate IS families (IS200/IS605, IS30, IS5, and IS3, respectively). IS667 and IS668 were also characterized as new members of the ISL3 family. Tn8521oi, which belongs to the Tn3 family as a new member, generated a 5-bp duplication of the target site sequence and carried complete 38-bp IRs. Of the eight protein-coding sequences (CDSs) identified in Tn8521oi, three CDSs (OB481, OB482, and OB483) formed a ger gene cluster, and two other paralogous gene clusters were found in the HTE831 genome. Most of the ISs and the group II intron widely distributed throughout the genome were inserted in noncoding regions, while two ISs (IS667-08 and IS668-02) and Oi.Int-04 were inserted in the coding regions.
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Affiliation(s)
- Yoshihiro Takaki
- Microbial Genome Research Group, Japan Agency for Marine-Earth Science and Technology, 2-15 Natsushima, Yokosuka 237-0061, Japan
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Burns DG, Camakaris HM, Janssen PH, Dyall-Smith ML. Cultivation of Walsby's square haloarchaeon. FEMS Microbiol Lett 2005; 238:469-73. [PMID: 15358434 DOI: 10.1016/j.femsle.2004.08.016] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2004] [Revised: 08/17/2004] [Accepted: 08/17/2004] [Indexed: 11/20/2022] Open
Abstract
The square haloarchaea of Walsby (SHOW group) dominate hypersaline microbial communities but have not been cultured since their discovery 25 years ago. We show that natural water dilution cultures can be used to isolate members of this group and, once in pure culture, they can be grown in standard halobacterial media. Cells display a square morphology and contain gas vesicles and poly-beta-hydroxybutyrate (PHB) granules. The 16S rRNA gene sequence was >99% identical to other SHOW group sequences. They prefer high salinities (23-30%), and can grow with a doubling time of 1-2 days in rich media. The ability to culture SHOW group organisms makes it possible to study, in a comprehensive way, the microbial ecology of salt lakes.
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Affiliation(s)
- David G Burns
- Department of Microbiology and Immunology, University of Melbourne, Vic. 3010, Australia
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Walsh DA, Bapteste E, Kamekura M, Doolittle WF. Evolution of the RNA polymerase B' subunit gene (rpoB') in Halobacteriales: a complementary molecular marker to the SSU rRNA gene. Mol Biol Evol 2004; 21:2340-51. [PMID: 15356285 DOI: 10.1093/molbev/msh248] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Many prokaryotes have multiple ribosomal RNA operons. Generally, sequence differences between small subunit (SSU) rRNA genes are minor (<1%) and cause little concern for phylogenetic inference or environmental diversity studies. For Halobacteriales, an order of extremely halophilic, aerobic Archaea, within-genome SSU rRNA sequence divergence can exceed 5%, rendering phylogenetic assignment problematic. The RNA polymerase B' subunit gene (rpoB') is a single-copy conserved gene that may be an appropriate alternative phylogenetic marker for Halobacteriales. We sequenced a fragment of the rpoB' gene from 21 species, encompassing 15 genera of Halobacteriales. To examine the utility of rpoB' as a phylogenetic marker in Halobacteriales, we investigated three properties of rpoB' trees: the variation in resolution between trees inferred from the rpoB' DNA and RpoB' protein alignment, the degree of mutational saturation between taxa, and congruence with the SSU rRNA tree. The rpoB' DNA and protein trees were for the most part congruent and consistently recovered two well-supported monophyletic groups, the clade I and clade II haloarchaea, within a collection of less well resolved Halobacteriales lineages. A comparison of observed versus inferred numbers of substitution revealed mutational saturation in the rpoB' DNA data set, particularly between more distant species. Thus, the RpoB' protein sequence may be more reliable than the rpoB' DNA sequence for inferring Halobacteriales phylogeny. AU tests of tree selection indicated the trees inferred from rpoB' DNA and protein alignments were significantly incongruent with the SSU rRNA tree. We discuss possible explanations for this incongruence, including tree reconstruction artifact, differential paralog sampling, and lateral gene transfer. This is the first study of Halobacteriales evolution based on a marker other than the SSU rRNA gene. In addition, we present a valuable phylogenetic framework encompassing a broad diversity of Halobacteriales, in which novel sequences can be inserted for evolutionary, ecological, or taxonomic investigations.
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Affiliation(s)
- David A Walsh
- Canadian Institute for Advanced Research Program in Evolutionary Biology, Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, Nova Scotia, Canada.
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Abstract
Summary Archaea, the third domain of life, were long thought to be limited to environmental extremes. However, the discovery of archaeal 16S rRNA gene sequences in water, sediment and soil samples has called into question the notion of Archaea as obligate extremophiles. Until now, none of these novel Archaea has been brought into culture, a critical step for discovering their ecological roles. We have cultivated three novel halophilic Archaea (haloarchaea) genotypes from sediments in which the pore-water salinity was close to that of sea water. All previously reported haloarchaeal isolates are obligate extreme halophiles requiring at least 9% (w/v) NaCl for growth and are typically the dominant heterotrophic organisms in salt and soda lakes, salt deposits and salterns. Two of these three newly isolated genotypes have lower requirements for salt than previously cultured haloarchaea and are capable of slow growth at sea-water salinity (2.5% w/v NaCl). Our data reveal the existence of Archaea that can grow in non-extreme conditions and of a diverse community of haloarchaea existing in coastal salt marsh sediments. Our findings suggest that the ecological range of these physiologically versatile prokaryotes is much wider than previously supposed.
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Affiliation(s)
- K J Purdy
- School of Animal and Microbial Sciences, University of Reading, Reading RG6 6AJ, UK.
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Elshahed MS, Najar FZ, Roe BA, Oren A, Dewers TA, Krumholz LR. Survey of archaeal diversity reveals an abundance of halophilic Archaea in a low-salt, sulfide- and sulfur-rich spring. Appl Environ Microbiol 2004; 70:2230-9. [PMID: 15066817 PMCID: PMC383155 DOI: 10.1128/aem.70.4.2230-2239.2004] [Citation(s) in RCA: 101] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2003] [Accepted: 12/12/2003] [Indexed: 11/20/2022] Open
Abstract
The archaeal community in a sulfide- and sulfur-rich spring with a stream water salinity of 0.7 to 1.0% in southwestern Oklahoma was studied by cloning and sequencing of 16S rRNA genes. Two clone libraries were constructed from sediments obtained at the hydrocarbon-exposed source of the spring and the microbial mats underlying the water flowing from the spring source. Analysis of 113 clones from the source library and 65 clones from the mat library revealed that the majority of clones belonged to the kingdom Euryarchaeota, while Crenarchaeota represented less than 10% of clones. Euryarchaeotal clones belonged to the orders Methanomicrobiales, Methanosarcinales, and Halobacteriales, as well as several previously described lineages with no pure-culture representatives. Those within the Halobacteriales represented 36% of the mat library and 4% of the source library. All cultivated members of this order are obligately aerobic halophiles. The majority of halobacterial clones encountered were not affiliated with any of the currently described genera of the family Halobacteriaceae. Measurement of the salinity at various locations at the spring, as well as along vertical gradients, revealed that soils adjacent to spring mats have a much higher salinity (NaCl concentrations as high as 32%) and a lower moisture content than the spring water, presumably due to evaporation. By use of a high-salt-plus-antibiotic medium, several halobacterial isolates were obtained from the microbial mats. Analysis of 16S rRNA genes indicated that all the isolates were members of the genus Haloferax. All isolates obtained grew at a wide range of salt concentrations, ranging from 6% to saturation, and all were able to reduce elemental sulfur to sulfide. We reason that the unexpected abundance of halophilic Archaea in such a low-salt, highly reduced environment could be explained by their relatively low salt requirement, which could be satisfied in specific locations of the shallow spring via evaporation, and their ability to grow under the prevalent anaerobic conditions in the spring, utilizing zero-valent sulfur compounds as electron acceptors. This study demonstrates that members of the Halobacteriales are not restricted to their typical high-salt habitats, and we propose a role for the Halobacteriales in sulfur reduction in natural ecosystems.
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Affiliation(s)
- Mostafa S Elshahed
- Department of Botany and Microbiology and Institute for Energy and the Environment, University of Oklahoma, Norman, Oklahoma 73019, USA
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Beard SJ, Hayes PK, Pfeifer F, Walsby AE. The sequence of the major gas vesicle protein, GvpA, influences the width and strength of halobacterial gas vesicles. FEMS Microbiol Lett 2002; 213:149-57. [PMID: 12167531 DOI: 10.1111/j.1574-6968.2002.tb11299.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Transformation experiments with Haloferax volcanii show that the amino acid sequence of the gas vesicle protein GvpA influences the morphology and strength of gas vesicles produced by halophilic archaea. A modified expression vector containing p-gvpA was used to complement a Vac(-) strain of Hfx. volcanii that harboured the entire p-vac region (from Halobacterium salinarum PHH1) except for p-gvpA. Replacement of p-gvpA with mc-gvpA (from Haloferax mediterranei) led to the synthesis of gas vesicles that were narrower and stronger. Other gene replacements (using c-gvpA from Hbt. salinarum or mutated p-gvpA sequences) led to a significant but smaller increase in gas vesicle strength, and less marked effects on gas vesicle morphology.
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Affiliation(s)
- Steven J Beard
- School of Biological Sciences, University of Bristol, Woodland Road, UK
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Abstract
There are many ways to select mutations that increase the stability of proteins, including rational design, functional screening of randomly generated mutant libraries, and comparison of naturally occurring homologous proteins. The protein engineer's toolbox is expanding and the number of successful examples of engineered protein stability is increasing. Still, the selection of thermostable mutations is not a standard process. Selection is complicated by lack of knowledge of the process that leads to thermal inactivation and by the fact that proteins employ a large variety of structural tricks to achieve stability.
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Litchfield CD, Gillevet PM. Microbial diversity and complexity in hypersaline environments: a preliminary assessment. J Ind Microbiol Biotechnol 2002; 28:48-55. [PMID: 11938471 DOI: 10.1038/sj/jim/7000175] [Citation(s) in RCA: 84] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2001] [Accepted: 06/15/2001] [Indexed: 11/09/2022]
Abstract
The microbial communities in solar salterns and a soda lake have been characterized using two techniques: BIOLOG, to estimate the metabolic potential, and amplicon length heterogeneity analysis, to estimate the molecular diversity of these communities. Both techniques demonstrated that the halophilic Bacteria and halophilic Archaea populations in the Eilat, Israel saltern are dynamic communities with extensive metabolic potentials and changing community structures. Halophilic Bacteria were detected in Mono Lake and the lower salinity ponds at the Shark Bay saltern in Western Australia, except when the crystallizer samples were stressed by exposure to Acid Green Dye #9899. At Shark Bay, halophilic Archaea were found only in the crystallizer samples. These data confirm both the metabolic diversity and the phylogenetic complexity of the microbial communities and assert the need to develop more versatile media for the cultivation of the diversity of bacteria in hypersaline environments.
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Affiliation(s)
- C D Litchfield
- Department of Biology, MS 3E1, George Mason University, Fairfax, VA 22030, USA
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Oren A. Diversity of halophilic microorganisms: environments, phylogeny, physiology, and applications. J Ind Microbiol Biotechnol 2002; 28:56-63. [PMID: 11938472 DOI: 10.1038/sj/jim/7000176] [Citation(s) in RCA: 352] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2001] [Accepted: 06/20/2001] [Indexed: 11/08/2022]
Abstract
The phylogenetic diversity of microorganisms living at high salt concentrations is surprising. Halophiles are found in each of the three domains: Archaea, Bacteria, and Eucarya. The metabolic diversity of halophiles is great as well: they include oxygenic and anoxygenic phototrophs, aerobic heterotrophs, fermenters, denitrifiers, sulfate reducers, and methanogens. The diversity of metabolic types encountered decreases with salinity. The upper salinity limit at which each dissimilatory process takes place is correlated with the amount of energy generated and the energetic cost of osmotic adaptation. Our understanding of the biodiversity in salt-saturated environments has increased greatly in recent years. Using a combination of culture techniques, molecular biological methods, and chemotaxonomic studies, we have obtained information on the nature of the halophilic Archaea as well as the halophilic Bacteria that inhabit saltern crystallizer ponds. Several halophilic microorganisms are being exploited in biotechnology. In some cases, such as the production of ectoine, the product is directly related to the halophilic behavior of the producing microorganism. In other cases, such as the extraction of beta-carotene from Dunaliella or the potential use of Haloferax species for the production of poly-beta-hydroxyalkanoate or extracellular polysaccharides, similar products can be obtained from non-halophiles, but halophilic microorganisms may present advantages over the use of non-halophilic counterparts.
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Affiliation(s)
- A Oren
- Division of Microbial and Molecular Ecology, The Institute of Life Sciences, and The Moshe Shilo Minerva Center for Marine Biogeochemistry, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
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Burggraf S, Ching A, Stetter KO, Woese CR. The sequence of Methanospirillum hungatei 23S rRNA confirms the specific relationship between the extreme halophiles and the Methanomicrobiales. Syst Appl Microbiol 2001; 14:358-63. [PMID: 11540074 DOI: 10.1016/s0723-2020(11)80310-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
We have determined the sequence of the 23S rRNA from the methanogenic archaeon Methanospirillum hungatei. This is the first such sequence from a member of the Methanomicrobiales. Moreover, it brings additional evidence to bear on the possible specific relationship between this particular group of methanogens and the extreme halophiles. Such evidence is critical in that several new (and relatively untested) methods of phylogenetic inference have lead to the controversial conclusion that the extreme halophiles are either not related to the archaea, or are only peripherally so. Analysis of the Methanospirillum hungatei 23S rRNA sequence shows the Methanomicrobiales are indeed a sister group of the extreme halophiles, further strengthening the conclusions reached from analysis of 16S rRNA sequences.
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Affiliation(s)
- S Burggraf
- Department of Microbiology, University of Illinois, Urbana 61801, USA
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Jolley KA, Maddocks DG, Gyles SL, Mullan Z, Tang SL, Dyall-Smith ML, Hough DW, Danson MJ. 2-Oxoacid dehydrogenase multienzyme complexes in the halophilic Archaea? Gene sequences and protein structural predictions. Microbiology (Reading) 2000; 146 ( Pt 5):1061-1069. [PMID: 10832633 DOI: 10.1099/00221287-146-5-1061] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
All Archaea catalyse the conversion of pyruvate to acetyl-CoA via a simple pyruvate oxidoreductase. This is in contrast to the Eukarya and most aerobic bacteria, which use the pyruvate dehydrogenase multienzyme complex [PDHC], consisting of multiple copies of three component enzymes: E1 (pyruvate decarboxylase), E2 (lipoate acetyl-transferase) and E3 (dihydrolipoamide dehydrogenase, DHLipDH). Until now no PDHC activity has been found in the Archaea, although DHLipDH has been discovered in the extremely halophilic Archaea and its gene sequence has been determined. In this paper, the discovery and sequencing of an operon containing the DHLipDH gene in the halophilic archaeon Haloferax volcanii are reported. Upstream of the DHLipDH gene are 3 ORFs which show highest sequence identities with the E1alpha, E1beta and E2 genes of the PDHC from gram-positive organisms. Structural predictions of the proposed protein product of the E2 gene show a domain structure characteristic of the E2 component in PDHCs, and catalytically important residues, including the lysine to which the lipoic acid cofactor is covalently bound, are conserved. Northern analyses indicate the transcription of the whole operon, but no PDHC enzymic activity could be detected in cell extracts. The presence in the E2 gene of an insertion (equivalent to approximately 100 aa) not found in bacterial or eukaryal E2 proteins, might be predicted to prevent multienzyme complex assembly. This is the first detailed report of the genes for a putative 2-oxoacid dehydrogenase complex in the Archaea, and the evolutionary and metabolic consequences of these findings are discussed.
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Affiliation(s)
- Keith A Jolley
- Centre for Extremophile Research, Department of Biology and Biochemistry, University of Bath, Bath BA2 7AY, UK1
| | - Deborah G Maddocks
- Centre for Extremophile Research, Department of Biology and Biochemistry, University of Bath, Bath BA2 7AY, UK1
| | - Shan L Gyles
- Centre for Extremophile Research, Department of Biology and Biochemistry, University of Bath, Bath BA2 7AY, UK1
| | - Zoë Mullan
- Centre for Extremophile Research, Department of Biology and Biochemistry, University of Bath, Bath BA2 7AY, UK1
| | - Sen-Lin Tang
- Department of Microbiology & Immunology, University of Melbourne, Parkville, Australia2
| | - Michael L Dyall-Smith
- Department of Microbiology & Immunology, University of Melbourne, Parkville, Australia2
| | - David W Hough
- Centre for Extremophile Research, Department of Biology and Biochemistry, University of Bath, Bath BA2 7AY, UK1
| | - Michael J Danson
- Centre for Extremophile Research, Department of Biology and Biochemistry, University of Bath, Bath BA2 7AY, UK1
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Montalvo-Rodríguez R, López-Garriga J, Vreeland RH, Oren A, Ventosa A, Kamekura M. Haloterrigena thermotolerans sp. nov., a halophilic archaeon from Puerto Rico. Int J Syst Evol Microbiol 2000; 50 Pt 3:1065-1071. [PMID: 10843046 DOI: 10.1099/00207713-50-3-1065] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
An extremely halophilic Archaeon belonging to the order Halobacteriales was isolated from the solar salterns of Cabo Rojo, Puerto Rico. The organism, designated strain PR5T, is rod-shaped, non-motile and requires at least 12% (w/v) NaCl to grow. The strain is highly thermotolerant: its temperature optimum is 50 degrees C and growth is possible up to 60 degrees C. Polar lipid analysis revealed the presence of the bis-sulfated glycolipid S2-DGD-1 as sole glycolipid and the absence of the glycerol diether analogue of phosphatidylglycerosulfate. Both C20,C20 and C20,C25 core lipids are present. The G+C content of the DNA is 63.3 mol%. According to 16S rDNA sequence data, strain PR5T is closely related to the representatives of the genera Haloterrigena and Natrinema, but on the basis of its phenotypic properties, 16S rDNA sequence and DNA-DNA hybridization studies, strain PR5T cannot be assigned to any of the recognized species within these genera. On the basis of its polar lipid composition, the isolate has been assigned to the genus Haloterrigena. The creation of a new species, Haloterrigena thermotolerans, is therefore proposed to accommodate this isolate. The type strain is strain PR5T (= DSM 11552T = ATCC 700275T).
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Briones C, Amils R. Nucleotide sequence of the 235 rRNA from Haloferax mediterranei and phylogenetic analysis of halophilic archaea based on LSU rRNA. Syst Appl Microbiol 2000; 23:124-31. [PMID: 10879986 DOI: 10.1016/s0723-2020(00)80053-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
Abstract
23S rRNA gene from the halophilic archaeon Haloferax mediterranei (strain ATCC 33500) was cloned and sequenced. Proceeding from the 2,912 nucleotides long sequence, the secondary structure of Haloferax genus large subunit rRNA was proposed. Haloferax mediterranei intergenic spacers 16S/23S and 23S/5S were also sequenced, and found to be 382 and 116 nucleotides long respectively. The 16S/23S spacer showed an Ala-tRNA intervening sequence, which is a common feature in Euryarchaeota. Sequence analysis of 23S rRNA and 16S rRNA was performed for the six organisms from the family Halobacteriaceae with both available gene sequences. Phylogenetic trees with completely different topology were obtained using both molecules.
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MESH Headings
- Base Sequence
- DNA, Archaeal/genetics
- DNA, Ribosomal Spacer/genetics
- Genes, rRNA
- Halobacteriales/classification
- Halobacteriales/genetics
- Haloferax mediterranei/classification
- Haloferax mediterranei/genetics
- Molecular Sequence Data
- Nucleic Acid Conformation
- Phylogeny
- RNA, Archaeal/chemistry
- RNA, Archaeal/genetics
- RNA, Ribosomal, 16S/genetics
- RNA, Ribosomal, 23S/chemistry
- RNA, Ribosomal, 23S/genetics
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Affiliation(s)
- C Briones
- Centro de Astrobiologia, INTA-CSIC, Madrid, Spain
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35
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Abstract
Seventeen alkaliphilic halomonads were examined for the presence of plasmids. Of these, eight strains harbored one or more from 5.3 to 33 kb in size, the first plasmids to be identified from an alkaliphilic halomonad source. Restriction and hybridization analysis revealed three strains that maintained an identical 5.9-kb plasmid which we named pAH1, two that had an identical 33-kb plasmid, and three others, of which one carried two plasmids of 5.3 and 15 kb, the former being designated pAH2. The two final strains maintained plasmids of 15 and 20.5 kb. Restriction mapping of both pAH1 and pAH2 indicated that they have a number of unique restriction sites and are of a small enough size to make them suitable for vector construction.
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Affiliation(s)
- S A Fish
- Department of Microbiology and Immunology, University of Leicester, Maurice Shock Building, Leicester, LE1 9HN, United Kingdom
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36
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Soppa J. Normalized nucleotide frequencies allow the definition of archaeal promoter elements for different archaeal groups and reveal base-specific TFB contacts upstream of the TATA box. Mol Microbiol 1999; 31:1589-92. [PMID: 10200975 DOI: 10.1046/j.1365-2958.1999.01274.x] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Abstract
Gas vesicles are intracellular, microbial flotation devices that consist of mainly one protein, GvpA. The formation of halobacterial gas vesicles occurs along a complex pathway involving 14 different gvp genes that are clustered in a genomic region termed the "vac region". Various vac regions found in Halobacterium salinarum (p-vac and c-vac), Haloferax mediterranei (mc-vac), and Natronobacterium vacuolatum (nv-vac) have been investigated. Except for the latter vac region, the arrangement of the gvp genes is identical. Single gvp genes have been mutated to study the effect on gas vesicle synthesis in transformants and to determine their possible function. Each vac region exhibits a characteristic transcription pattern, and regulatory steps have been observed at the DNA, RNA, and protein level, indicating a complex regulatory network acting during gas vesicle gene expression.
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Affiliation(s)
- F Pfeifer
- Institut für Mikrobiologie und Genetik, Technische Hochschule Darmstadt, Schnittspahnstrasse 10, D-64287 Darmstadt, Germany.
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38
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Steinert K, Wagner V, Kroth-Pancic PG, Bickel-Sandkötter S. Characterization and subunit structure of the ATP synthase of the halophilic archaeon Haloferax volcanii and organization of the ATP synthase genes. J Biol Chem 1997; 272:6261-9. [PMID: 9045643 DOI: 10.1074/jbc.272.10.6261] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
The archaeal ATPase of the halophile Haloferax volcanii synthesizes ATP at the expense of a proton gradient, as shown by sensitivity to the uncoupler carboxyl cyanide p-trifluoromethoxyphenylhydrazone, to the ionophore nigericin, and to the proton channel-modifying reagent N,N'-dicyclohexylcarbodiimide. The conditions for an optimally active ATP synthase have been determined. We were able to purify the enzyme complex and to identify the larger subunits with antisera raised against synthetic peptides. To identify additional subunits of this enzyme complex, we cloned and sequenced a gene cluster encoding five hydrophilic subunits of the A1 part of the proton-translocating archaeal ATP synthase. Initiation, termination, and ribosome-binding sequences as well as the result of a single transcript suggest that the ATPase genes are organized in an operon. The calculated molecular masses of the deduced gene products are 22. 0 kDa (subunit D), 38.7 kDa (subunit C), 11.6 kDa (subunit E), 52.0 kDa (subunit B), and 64.5 kDa (subunit A). The described operon contains genes in the order D, C, E, B, and A; it contains no gene for the hydrophobic, so-called proteolipid (subunit c, the proton-conducting subunit of the A0 part). This subunit has been isolated and purified; its molecular mass as deduced by SDS-polyacrylamide gel electrophoresis is 9.7 kDa.
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Affiliation(s)
- K Steinert
- Institut für Biochemie der Pflanzen, Heinrich-Heine-Universität Düsseldorf, Universitätsstrasse 1, D-40225 Düsseldorf, Federal Republic of Germany
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Abstract
By deleting the radA open reading frame of an extreme halophile, Haloferax volcanii, we created and characterized a recombination-deficient archaeon. This strain, Hf. volcanii DS52, has no detectable DNA recombination, is more sensitive to DNA damage by UV light and ethylmethane sulfonate, and has a slower growth rate than the wild type. These characteristics are similar to those observed in recombination mutants of Eukarya and Bacteria, and show that the radA gene belongs in the recA/RAD51 family by function as well as sequence homology. In addition, strain DS52 was not transformable by plasmids pWL102 or pUBP2 (which contain pHV2 and pHH1 replicons, respectively), although it was readily transformed by plasmids containing a pHK2 replicon, indicating a role for radA in the maintenance or replication of some halobacterial plasmids. Despite its slower growth rate, Hf. volcanii DS52 was still easy to culture and transform, and should be suitable for use in studies where a recombination-deficient background is desired.
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Affiliation(s)
- W G Woods
- Department of Microbiology, University of Melbourne, Parkville, Australia
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40
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Taupin CM, Härtlein M, Leberman R. Seryl-tRNA synthetase from the extreme halophile Haloarcula marismortui--isolation, characterization and sequencing of the gene and its expression in Escherichia coli. Eur J Biochem 1997; 243:141-50. [PMID: 9030733 DOI: 10.1111/j.1432-1033.1997.0141a.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The seryl-tRNA synthetase from the extreme halophilic archaebacterium Haloarcula marismortui, belonging to the group Euryarchaeota, has been purified and its hyperhalophilic behavior demonstrated by activity and stability tests in KCl, NaCl and MgCl2 solutions. Although the natural external environment of this archaebacterium is rich in sodium ions and poor in potassium ions, the converse being the case in the bacterial cytosol. there is no large significant difference in activity and stability in vitro of the enzyme between solutions of NaCl and KCl. Low, but not high, concentrations of MgCl2 stabilize the enzyme. The enzyme aminoacylates tRNA from Escherichia coli even under the high salt conditions of the assay. A fluorescence study indicated that low salt denaturation of the hyperhalophilic enzyme is a biphasic process. The hyperhalophilic enzyme demonstrated immunological reactivity with antisera against the catalytic domain of the homologous E. coli enzyme. The gene coding for the H. marismortui enzyme has been isolated and sequenced. The derived amino acid sequence is the first of a hyperhalophilic aminoacyl-tRNA synthetase. The wild-type gene and a mutant gene with a deletion of the halophile-specific insertion were expressed in E. coli using the T7 RNA polymerase and the Thiofusion expression systems. None of the expressed proteins were enzymically active. A structural model has been produced by comparison with other seryl-tRNA synthetases which illustrates the high negative-charge density of the surface of the hyperhalophilic enzyme.
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41
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McCready S. The repair of ultraviolet light-induced DNA damage in the halophilic archaebacteria, Halobacterium cutirubrum, Halobacterium halobium and Haloferax volcanii. Mutat Res 1996; 364:25-32. [PMID: 8814335 DOI: 10.1016/0921-8777(96)00018-3] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Extremely halophilic archaebacteria have been reported to have no capacity for dark repair (excision repair) of ultraviolet damage and to rely on very efficient photoreactivation for recovery after UVC irradiation. Post-UV incubation in the light restores 100% survival in these organisms. This has been taken to indicate that cyclobutane dimers are the only significant UV-induced lesions and that they are completely repaired by photoreactivation. However, in all organisms studied to date, pyrimidine (6-4) pyrimidone photoproducts are a significant cytotoxic and mutagenic lesion and constitute 10-30% of UV photoproducts. The question arises, therefore--are 6-4 photoproducts induced in the halophilic archaebacteria and, if they are, how are they repaired? This paper shows that both cyclobutane dimers and 6-4 photoproducts are induced in the extremely halophilic archaebacteria, Halobacterium cutirubrum, Halobacterium halobium and Haloferax volcanii, at similar levels as in other organisms. Furthermore, contrary to previous reports, there is dark repair of both lesions. As in other organisms, 6-4 photoproducts are removed more efficiently than cyclobutane dimers in the dark. In the light, cyclobutane dimers are repaired very rapidly and there is also photoenhanced repair of 6-4 photoproducts. This work confirms that organisms such as Halobacterium and Haloferax which live in conditions of high exposure to sunlight have very efficient rates of repair of UV lesions in the light.
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Affiliation(s)
- S McCready
- Department of Biochemistry, University of Oxford, UK.
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42
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Abstract
Through hybridization of available probes, we have added nine genes to the macrorestriction map of the Haloferax mediterranei chromosome and five genes to the contig map of Haloferax volcanii. Additionally, we hybridized 17 of the mapped cosmid clones from H. volcanii to the H. mediterranei genome. The resulting 35-point chromosomal comparison revealed only two inversions and a few translocations. Forces known to promote rearrangement, common in the haloarchaea, have been ineffective in changing global gene order throughout the nearly 10(7) years of these species' divergent evolution.
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Affiliation(s)
- P López-García
- Centro de Biología Molecular, Universidad Autónoma de Madrid, Spain
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43
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Abstract
We have used a modified intron-containing tRNA(Pro(UGG) gene (tRNA(ProM), derived from the Saccharomyces cerevisiae tRNA(Pro(UGG) gene, as a reporter to measure in vivo transcription from a halophilic archaeon promoter. Coupling of the yeast tRNA(ProM) gene to the Haloferax volcanii tRNA(Lys) promoter on the H. volcanii plasmid pWL201 led to the production of a single stable transcript that was readily quantitated by Northern (RNA) blot analysis. Comparison of tRNA(ProM) RNA production from constructs containing the wild-type tRNA(Lys) promoter and those containing mutant tRNA(Lys) promoters demonstrated that this assay system can be used to measure expression from strong and weak promoters.
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Affiliation(s)
- J R Palmer
- Department of Microbiology, Ohio State University, Columbus 43210
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McKune K, Woychik NA. Halobacterial S9 operon contains two genes encoding proteins homologous to subunits shared by eukaryotic RNA polymerases I, II, and III. J Bacteriol 1994; 176:4754-6. [PMID: 8045907 PMCID: PMC196299 DOI: 10.1128/jb.176.15.4754-4756.1994] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
One key component of the eukaryotic transcriptional apparatus is the multisubunit enzyme RNA polymerase II. We have discovered that two of the subunits shared by the three nuclear RNA polymerases in the yeast Saccharomyces cerevisiae, RPB6 and RPB10, have counterparts among the Archaea.
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Affiliation(s)
- K McKune
- Roche Institute of Molecular Biology, Nutley, New Jersey 07110
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45
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Nuttall SD, Dyall-Smith ML. Ch2, a novel halophilic archaeon from an Australian solar saltern. Int J Syst Bacteriol 1994; 44:375. [PMID: 8186104 DOI: 10.1099/00207713-44-2-375a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Affiliation(s)
- S D Nuttall
- Department of Microbiology, University of Melbourne, Parkville, Victoria, Australia
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46
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Abstract
The reconstruction of phylogenetic trees from DNA and protein sequences is confounded by unequal rate effects. These effects can group rapidly evolving taxa with other rapidly evolving taxa, whether or not they are genealogically related. All algorithms are sensitive to these effects whenever the assumptions on which they are based are not met. The algorithm presented here, called paralinear distances, is valid for a much broader class of substitution processes than previous algorithms and is accordingly less affected by unequal rate effects. It may be used with all nucleic acid, protein, or other sequences, provided that their evolution may be modeled as a succession of Markov processes. The properties of the method have been proven both analytically and by computer simulations. Like all other methods, paralinear distances can fail when sequences are misaligned or when site-to-site sequence variation of rates is extensive. To examine the usefulness of paralinear distances, the "origin of the eukaryotes" has been investigated by the analysis of elongation factor Tu sequences with a variety of sequence alignments. It has been found that the order in which sequences are pairwise aligned strongly determines the topology which is reconstructed by paralinear distances (as it does for all other reconstruction methods tested). When the parts of the alignment that are unaffected by alignment order are analyzed, paralinear distances strongly select the eocyte topology. This provides evidence that the eocyte prokaryotes are the closest prokaryotic relatives of the eukaryotes.
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Affiliation(s)
- J A Lake
- Molecular Biology Institute, University of California, Los Angeles 90024
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47
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Abstract
Two genomic sequences from the halophilic archaeon Haloferax mediterranei, where we had found PstI restriction-pattern modifications depending on the salinity of the growth medium, have been studied. A markedly salt-dependent differential expression has been detected in the nearby regions. Two of the open reading frames characterized correspond to two of the differentially expressed transcripts. In both cases the PstI sites were included in purine-pyrimidine alternancies suggestive of Z-DNA structures and located in non-coding regions with frequent repetitive motifs. A long alternating adenine-thymine tract also appears in the upstream regions of one of these open reading frames. A possible role of local DNA configuration in osmoregulation in this organism is discussed.
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Affiliation(s)
- F J Mojica
- Departamento de Genética Molecular y Microbiología, Universidad de Alicante, Spain
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48
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Englert C, Wanner G, Pfeifer F. Functional analysis of the gas vesicle gene cluster of the halophilic archaeon Haloferax mediterranei defines the vac-region boundary and suggests a regulatory role for the gvpD gene or its product. Mol Microbiol 1992; 6:3543-50. [PMID: 1282192 DOI: 10.1111/j.1365-2958.1992.tb01789.x] [Citation(s) in RCA: 54] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
A series of deletions introduced into the gvp gene cluster of Haloferax mediterranei, comprising 14 genes involved in gas vesicle synthesis (mc-vac-region), was investigated by transformation experiments. Gas vesicle production and the expression of the gvpA gene encoding the major gas vesicle protein, GvpA, was monitored in each Haloferax volcanii transformant. Whereas transformants containing the entire mc-vac-region produced gas vesicles (Vac+), various deletions in the region 5' to gvpA (encompassing gvpD-gvpM) or 3' to gvpA (containing gvpC, gvpN and gvpO) revealed Vac- transformants. All these transformants expressed gvpA and contained the 8 kDa GvpA protein as shown by Western analysis. However, transformants containing the gvpA gene by itself indicated a lower level of GvpA than observed with each of the other transformants. None of these transformants containing deletion constructs assembled the GvpA protein into gas vesicles. In contrast, transformants containing a construct carrying a 918 bp deletion internal to gvpD exhibited a tremendous gas vesicle overproduction, suggesting a regulatory role for the gvpD gene or its product. This is the first assignment of a functional role for one of the 13 halobacterial gvp genes found in addition to gvpA that are involved in the synthesis of this unique structure.
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Affiliation(s)
- C Englert
- Max-Planck-Institut für Biochemie, Martinsried, Germany
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49
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Otomo J, Urabe Y, Tomioka H, Sasabe H. The primary structures of helices A to G of three new bacteriorhodopsin-like retinal proteins. J Gen Microbiol 1992; 138:2389-96. [PMID: 1479357 DOI: 10.1099/00221287-138-11-2389] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The primary structures of helices A to G of all bacteriorhodopsin (BR)-like retinal proteins identified in newly isolated halobacteria have been determined from the nucleotide sequence of the BR-like protein genes. Using PCR methods, gene fragments encoding the A- to G-helix region of BR-like proteins were directly amplified from the total genomic DNA of the seven new halobacterial strains. Oligonucleotide primers corresponding to highly conserved regions in the helices A to G were designed from the nucleotide sequences of bacterioopsin (bop) and archaeopsin-I (aop-I), and some primers were effective for the amplification of the gene encoding C- to G-helix region of all new BR-like proteins. The primer corresponding to A-helix region was designed either from the nucleotide sequence of bop and aop-I or from the N-terminus amino acid sequence of a BR-like protein. Three new BR-like proteins were identified from the amino acid sequence, which was deduced from the nucleotide sequence of the genes encoding A- to G-helix region of the BR-like proteins. It was found that not only the amino acid sequence, but also the nucleotide sequence of the gene encoding the C- and G-helix region, in which a number of important residues for proton translocation are located, is highly conserved in three new BR-like proteins. Analysis of the primary structures of the A- to G-helix region of new BR-like proteins revealed that one has about 85% homology with aR-I and aR-II, and the rest have about 55% homology with halobium BR, aR-I and aR-II.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- J Otomo
- Frontier Research Program, RIKEN Institute, Saitama, Japan
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Cline SW, Doolittle WF. Transformation of members of the genus Haloarcula with shuttle vectors based on Halobacterium halobium and Haloferax volcanii plasmid replicons. J Bacteriol 1992; 174:1076-80. [PMID: 1732202 PMCID: PMC206205 DOI: 10.1128/jb.174.3.1076-1080.1992] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
We have stably transformed both Haloarcula vallismortis and Haloarcula hispanica with the halobacterium-Escherichia coli shuttle vectors pWL102 (based on the Haloferax volcanii pHV2 replicon) and pUBP2 (based on the Halobacterium halobium pHH1 replicon). Haloferax volcanii, Halobacterium halobium, and Haloarcula vailismortis are equally distant from one another and span the phylogenetic depth of the halophilic Archaea; thus, these vectors may be generally useful for the halophiles. Both Haloarcula vallismortis and Haloarcula hispanica exhibit previously unreported complex life cycles and are therefore significant as genetically approachable models of cellular differentiation within the Archaea.
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Affiliation(s)
- S W Cline
- Department of Biochemistry, Dalhousie University, Halifax, Nova Scotia, Canada
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