Dual mechanisms of xylose uptake in the thermophilic bacterium Thermoanaerobacter thermohydrosulfuricus

Cook, G

doi:10.1016/0378-1097(94)90044-2

Cited by 5 publications

(4 citation statements)

References 20 publications

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“…No diauxic shifts were observed and carbohydrates were simultaneously utilised in all of the carbohydrate combinations tested (Supplementary Figure 4), indicating a lack of carbon catabolite repression and non-diauxic growth. Non-diauxic growth has been observed previously in Sulfolobus acidocaldarius and Thermoanaerobacter thermohydrosulfuricus, and was attributed to the lack of a carbohydrate phosphotransferase system (PTS; Cook et al, 1993Cook et al, , 1994Joshua et al, 2011). The T49 T genome also lacks any transporter genes associated with PTS.…”

Section: Regulation Of Carbohydrate Metabolismmentioning

confidence: 90%

Genomic analysis of Chthonomonas calidirosea, the first sequenced isolate of the phylum Armatimonadetes

et al. 2014

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Most of the lineages of bacteria have remained unknown beyond environmental surveys using molecular markers. Until the recent characterisation of several strains, the phylum Armatimonadetes (formerly known as 'candidate division OP10') was a dominant and globally-distributed lineage within this 'uncultured majority'. Here we report the first Armatimonadetes genome from the thermophile Chthonomonas calidirosea T49 T and its role as a saccharide scavenger in a geothermal steam-affected soil environment. Phylogenomic analysis indicates T49 T to be related closely to the phylum Chloroflexi. The predicted genes encoding for carbohydrate transporters (27 carbohydrate ATP-binding cassette transporter-related genes) and carbohydrate-metabolising enzymes (including at least 55 putative enzymes with glycosyl hydrolase domains) within the 3.43 Mb genome help explain its ability to utilise a wide range of carbohydrates as well as its inability to break down extracellular cellulose. The presence of only a single class of branched amino acid transporter appears to be the causative step for the requirement of isoleucine for growth. The genome lacks many commonly conserved operons (for example, lac and trp). Potential causes for this, such as dispersion of functionally related genes via horizontal gene transfer from distant taxa or recent genome recombination, were rejected. Evidence suggests T49 T relies on the relatively abundant r-factors, instead of operonic organisation, as the primary means of transcriptional regulation. Examination of the genome with physiological data and environmental dynamics (including interspecific interactions) reveals ecological factors behind the apparent elusiveness of T49 T to cultivation and, by extension, the remaining 'uncultured majority' that have so far evaded conventional microbiological techniques.

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Section: Regulation Of Carbohydrate Metabolismmentioning

confidence: 90%

Genomic analysis of Chthonomonas calidirosea, the first sequenced isolate of the phylum Armatimonadetes

et al. 2014

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“…Indirect evidence based on the effects of metabolic inhibitors and uncouplers on glucose transport in Clostridium thermocellum and C. thermohydrosulfuricum (now Thermoanaerobacter thermohydrosulfuricus) has suggested that transport is dependent on ATP rather than a proton or sodium gradient (15,29). Recently, it has been proposed that glucose and xylose are taken up by Thermoanaerobacter thermohydrosulfuricus through a facilitated diffusion mechanism (8,9). On the other hand, in C. thermosulfurogenes EM1 (now Thermoanaerobacterium thermosulfurigenes), two genes, amyC and amyD, which are homologous to two membrane components of the maltose and glycerol-3-phosphate transport systems of E. coli, were found (3).…”

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confidence: 99%

Molecular analysis of the amy gene locus of Thermoanaerobacterium thermosulfurigenes EM1 encoding starch-degrading enzymes and a binding protein-dependent maltose transport system

et al. 1996

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A gene of Thermoanaerobacterium thermosulfurigenes EM1 encoding a protein with similarity to the maltosebinding protein of Escherichia coli was cloned and sequenced. It was located in the amy gene region of the chromosome downstream of the pullulanase-encoding amyB gene and upstream of amyDC, encoding membrane components of an ABC transport system, and the ␣-amylase gene amyA. The gene was designated amyE. Analysis of mRNA by Northern (RNA) blotting revealed that expression of the amy gene region is repressed during growth on glucose. Maximum levels of mRNA were detected with maltose as a substrate. An operon which was transcribed in the order amyBEDC was identified. However, an additional transcription start point was found in front of amyE. The amyA gene represented a monocistronic operon. Putative ؊35 and ؊10 promoter sites were deduced from the three transcription start sites of the amy gene region, and possible regulatory regions mediating induction by maltose and catabolite repression by glucose were identified by sequence analysis and comparison. The biochemical characterization of maltose uptake in T. thermosulfurigenes EM1 revealed two transport systems with K m values of 7 M (high affinity) and 400 M (low affinity). We conclude that the high-affinity system, which is specific for maltose and maltotriose, is a binding-proteindependent transporter encoded by amyEDC. The gene for the putative ATP-binding protein has not yet been identified, and in contrast to similar systems in other bacteria, it is not located in the immediate vicinity of the chromosome.Starch-degrading enzymes from thermophilic microorganisms have been extensively studied in recent years. Several enzymes have been purified and characterized (21,26,37), and in many cases the corresponding genes have been cloned, analyzed, and expressed in Escherichia coli or Bacillus subtilis (2,7,24,27). On the other hand, regulation of gene expression and enzyme synthesis as well as transport of the soluble products of the depolymerases into the cell have received surprisingly little attention. It is clear that transport mechanisms are similar to those in other bacteria. To date, only a limited number of studies on carbohydrate transport in thermophiles have been published. A phosphotransferase system for glucose or cellobiose in thermophiles has not yet been found. Indirect evidence based on the effects of metabolic inhibitors and uncouplers on glucose transport in Clostridium thermocellum and C. thermohydrosulfuricum (now Thermoanaerobacter thermohydrosulfuricus) has suggested that transport is dependent on ATP rather than a proton or sodium gradient (15, 29). Recently, it has been proposed that glucose and xylose are taken up by Thermoanaerobacter thermohydrosulfuricus through a facilitated diffusion mechanism (8, 9). On the other hand, in C. thermosulfurogenes EM1 (now Thermoanaerobacterium thermosulfurigenes), two genes, amyC and amyD, which are homologous to two membrane components of the maltose and glycerol-3-phosphate transport systems of E. c...

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“…This study has demonstrated that the Gram‐positive, broad host range plasmid pUB110 can be introduced by electroporation into eight strains of Bu. fibrisolvens , representing all three groups currently recognized by 16S rRNA‐based phylogeny (Cook et al . 1994; Forster et al .…”

Section: Discussionmentioning

confidence: 99%

Transformation and expression of an anaerobic fungal xylanase in several strains of the rumen bacteriumButyrivibrio fibrisolvens

Gobius

Gong

Aylward

et al. 2002

Journal of Applied Microbiology

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Aims: To obtain reliable transformation of a range of Butyrivibrio fibrisolvens strains and to express a Neocallimastix patriciarum xylanase gene in the recipients. Methods and Results: Eight strains (H17c, E14, LP1309, LP1028, AR11a, OB156, LP210B and LP461A) of Bu. fibrisolvens were transformed by the Gram‐positive vector pUB110. A xylanase expression/secretion cassette containing Bu. fibrisolvens promoter and signal peptide elements fused to catalytic domain II of the N. patriciarum xylanase A cDNA (xynANp) was inserted into pUB110 to create the plasmid pUBxynA. pUBxynA was used to transform seven of the Bu. fibrisolvens strains transformed by pUB110. In strain H17c pUBxynA, which produced native xylanase, 2·46 U mg−1 total xylanase activity was produced with 45% extracellular xylanase. In strain H17c pUMSX, 0·74 U mg−1 total xylanase activity was produced with 98% extracellular xylanase. H17c pUBxynA exhibited increased (28·7%) degradation of neutral detergent fibre compared with unmodified H17c; however, progressive loss of pUBxynA was observed in long‐term cultivation. Conclusions: A stable transformation system was developed that was applicable for a range of Bu. fibrisolvens strains and high levels of expression of a recombinant xylanase were obtained in H17c which lead to increased fibre digestion. Significance and Impact of the Study: This stable transformation system with the accompanying recombinant plasmids will be a useful tool for further investigation aimed at improving ruminal fibre digestion.

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Dual mechanisms of xylose uptake in the thermophilic bacterium Thermoanaerobacter thermohydrosulfuricus

Cited by 5 publications

References 20 publications

Genomic analysis of Chthonomonas calidirosea, the first sequenced isolate of the phylum Armatimonadetes

Genomic analysis of Chthonomonas calidirosea, the first sequenced isolate of the phylum Armatimonadetes

Molecular analysis of the amy gene locus of Thermoanaerobacterium thermosulfurigenes EM1 encoding starch-degrading enzymes and a binding protein-dependent maltose transport system

Transformation and expression of an anaerobic fungal xylanase in several strains of the rumen bacteriumButyrivibrio fibrisolvens

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