The genus<i>Thermotoga</i>: recent developments

Frock, Andrew D.; Notey, Jaspreet; Kelly, Robert M.

doi:10.1080/09593330.2010.484076

Cited by 57 publications

(20 citation statements)

References 97 publications

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“…It has been shown that MRE11 can be associated with RAD50 to actively bind DNA. This complex forms a catalytic head that contains an ATP-stimulated nuclease and DNA binding activity that indicates its potential role in processing DNA double-stranded breaks in T. maritima (2,30,32,33). It was also found here that a minimum of 100 nt was required for recombination and that a putative recombinogenic sequence (AGCGG) located at the 3= end of pyrE and upstream region of pyrE may play a role in recombination at that locus.…”

Section: Discussionsupporting

confidence: 57%

Contribution of Pentose Catabolism to Molecular Hydrogen Formation by Targeted Disruption of Arabinose Isomerase ( araA ) in the Hyperthermophilic Bacterium Thermotoga maritima

White

Singh

Rudrappa

et al. 2017

Appl Environ Microbiol

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Thermotoga maritima ferments a broad range of sugars to form acetate, carbon dioxide, traces of lactate, and near theoretic yields of molecular hydrogen (H 2 ). In this organism, the catabolism of pentose sugars such as arabinose depends on the interaction of the pentose phosphate pathway with the Embden-Myerhoff and Entner-Doudoroff pathways. Although the values for H 2 yield have been determined using pentose-supplemented complex medium and predicted by metabolic pathway reconstruction, the actual effect of pathway elimination on hydrogen production has not been reported due to the lack of a genetic method for the creation of targeted mutations. Here, a spontaneous and genetically stable pyrE deletion mutant was isolated and used as a recipient to refine transformation methods for its repair by homologous recombination. To verify the occurrence of recombination and to assess the frequency of crossover events flanking the deleted region, a synthetic pyrE allele, encoding synonymous nucleotide substitutions, was used. Targeted inactivation of araA (encoding arabinose isomerase) in the pyrE mutant was accomplished using a divergent, codon-optimized Thermosipho africanus pyrE allele fused to the T. maritima groES promoter as a genetic marker. Mutants lacking araA were unable to catabolize arabinose in a defined medium. The araA mutation was then repaired using targeted recombination. Levels of synthesis of H 2 using arabinosesupplemented complex medium by wild-type and araA mutant cell lines were compared. The difference between strains provided a direct measurement of H 2 production that was dependent on arabinose consumption. Development of a targeted recombination system for genetic manipulation of T. maritima provides a new strategy to explore H 2 formation and life at an extremely high temperature in the bacterial domain.IMPORTANCE We describe here the development of a genetic system for manipulation of Thermotoga maritima. T. maritima is a hyperthermophilic anaerobic bacterium that is well known for its efficient synthesis of molecular hydrogen (H 2 ) from the fermentation of sugars. Despite considerable efforts to advance compatible genetic methods, chromosome manipulation has remained elusive and hindered use of T. maritima or its close relatives as model hyperthermophiles. Lack of a genetic method also prevented efforts to manipulate specific metabolic pathways to measure their contributions to H 2 yield. To overcome this barrier, a homologous chromosomal recombination method was developed and used to characterize the contribution of arabinose catabolism to H 2 formation. We report here a stable genetic

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Section: Discussionsupporting

confidence: 57%

Contribution of Pentose Catabolism to Molecular Hydrogen Formation by Targeted Disruption of Arabinose Isomerase ( araA ) in the Hyperthermophilic Bacterium Thermotoga maritima

White

Singh

Rudrappa

et al. 2017

Appl Environ Microbiol

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“…The 10 Thermotoga species currently identified can clearly be divided into one group with optimum growth temperatures of 65 to 70°C and another group with optimum growth temperatures of 75 to 80°C (Table 1). 16S rRNA sequences indicate that the isolates with higher optimum growth temperatures are more closely related (Ն99% identical) to each other than to the less thermophilic Thermotoga strains (15). Complete genome sequences are available for seven Thermotoga species, and all of these, except for T. lettingae and T. thermarum, belong to the group of higher-temperature species (Table 1).…”

Section: Resultsmentioning

confidence: 99%

Hyperthermophilic Thermotoga Species Differ with Respect to Specific Carbohydrate Transporters and Glycoside Hydrolases

Frock

Gray

Kelly

2012

Appl Environ Microbiol

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Four hyperthermophilic members of the bacterial genus Thermotoga (T. maritima, T. neapolitana, T. petrophila, and Thermotoga sp. strain RQ2) share a core genome of 1,470 open reading frames (ORFs), or about 75% of their genomes. Nonetheless, each species exhibited certain distinguishing features during growth on simple and complex carbohydrates that correlated with genomic inventories of specific ABC sugar transporters and glycoside hydrolases. These differences were consistent with transcriptomic analysis based on a multispecies cDNA microarray. Growth on a mixture of six pentoses and hexoses showed no significant utilization of galactose or mannose by any of the four species. T. maritima and T. neapolitana exhibited similar monosaccharide utilization profiles, with a strong preference for glucose and xylose over fructose and arabinose. Thermotoga sp. strain RQ2 also used glucose and xylose, but was the only species to utilize fructose to any extent, consistent with a phosphotransferase system (PTS) specific for this sugar encoded in its genome. T. petrophila used glucose to a significantly lesser extent than the other species. In fact, the XylR regulon was triggered by growth on glucose for T. petrophila, which was attributed to the absence of a glucose transporter (XylE2F2K2), otherwise present in the other Thermotoga species. This suggested that T. petrophila acquires glucose through the XylE1F1K1 transporter, which primarily serves to transport xylose in the other three Thermotoga species. The results here show that subtle differences exist among the hyperthermophilic Thermotogales with respect to carbohydrate utilization, which supports their designation as separate species.

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“…maritima, over 70 bacterial species belonging to this phylum have been isolated from a variety of geothermal or volcanically heated environments including oil reservoirs, hydrothermal vents, terrestrial hot springs, etc. (Patel et al 1985;Antoine et al 1997;Reysenbach 2001;Alain et al 2002;Balk et al 2002;Urios et al 2004;Huber and Hannig 2006;Dipippo et al 2009;Frock et al 2010). Recently, the presence of bacteria related to the Thermotogales has also been reported in mesophilic, low temperature environments (Nesbo et al 2010).…”

Section: Introductionmentioning

confidence: 97%

Phylogeny and molecular signatures for the phylum Thermotogae and its subgroups

Gupta

Bhandari

2011

Antonie van Leeuwenhoek

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Thermotogae species are currently identified mainly on the basis of their unique toga and distinct branching in the rRNA and other phylogenetic trees. No biochemical or molecular markers are known that clearly distinguish the species from this phylum from all other bacteria. The taxonomic/evolutionary relationships within this phylum, which consists of a single family, are also unclear. We report detailed phylogenetic analyses on Thermotogae species based on concatenated sequences for many ribosomal as well as other conserved proteins that identify a number of distinct clades within this phylum. Additionally, comprehensive analyses of protein sequences from Thermotogae genomes have identified >60 Conserved Signature Indels (CSI) that are specific for the Thermotogae phylum or its different subgroups. Eighteen CSIs in important proteins such as PolI, RecA, TrpRS and ribosomal proteins L4, L7/L12, S8, S9, etc. are uniquely present in various Thermotogae species and provide molecular markers for the phylum. Many CSIs were specific for a number of Thermotogae subgroups. Twelve of these CSIs were specific for a clade consisting of various Thermotoga species except Tt. lettingae, which was separated from other Thermotoga species by a long branch in phylogenetic trees; Fourteen CSIs were specific for a clade consisting of the Fervidobacterium and Thermosipho genera and eight additional CSIs were specific for the genus Thermosipho. In addition, the existence of a clade consisting of the deep branching species Petrotoga mobilis, Kosmotoga olearia and Thermotogales bacterium mesG1 was supported by seven CSIs. The deep branching of this clade was also supported by a number of CSIs that were present in various Thermotogae species, but absent in this clade and all other bacteria. Most of these clades were strongly supported by phylogenetic analyses based on two datasets of protein sequences and they identify potential higher taxonomic grouping (viz. families) within this phylum. We also report 16 CSIs that are shared by either some or all Thermotogae species and some species from other taxa such as Archaea, Aquificae, Firmicutes, Proteobacteria, Deinococcus, Fusobacteria, Dictyoglomus, Chloroflexi and eukaryotes. The shared presence of some of these CSIs could be due to lateral gene transfers between these groups. However, no clear preference for any particular group was observed in this regard. The molecular probes based on different genes/proteins, which contain these Thermotogae-specific CSIs, provide novel and highly specific means for identification of both known as well as previously unknown Thermotogae species in different environments. Additionally, these CSIs also provide valuable tools for genetic and biochemical studies that could lead to discovery of novel properties that are unique to these bacteria.

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The genusThermotoga: recent developments

Cited by 57 publications

References 97 publications

Contribution of Pentose Catabolism to Molecular Hydrogen Formation by Targeted Disruption of Arabinose Isomerase ( araA ) in the Hyperthermophilic Bacterium Thermotoga maritima

Contribution of Pentose Catabolism to Molecular Hydrogen Formation by Targeted Disruption of Arabinose Isomerase ( araA ) in the Hyperthermophilic Bacterium Thermotoga maritima

Hyperthermophilic Thermotoga Species Differ with Respect to Specific Carbohydrate Transporters and Glycoside Hydrolases

Phylogeny and molecular signatures for the phylum Thermotogae and its subgroups

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