scholarly journals In Silico and Transcriptional Analysis of Carbohydrate Uptake Systems of Streptomyces coelicolor A3(2)

2004 ◽  
Vol 186 (5) ◽  
pp. 1362-1373 ◽  
Author(s):  
Ralph Bertram ◽  
Maximilian Schlicht ◽  
Kerstin Mahr ◽  
Harald Nothaft ◽  
Milton H. Saier ◽  
...  

ABSTRACT Streptomyces coelicolor is the prototype for the investigation of antibiotic-producing and differentiating actinomycetes. As soil bacteria, streptomycetes can metabolize a wide variety of carbon sources and are hence vested with various specific permeases. Their activity and regulation substantially determine the nutritional state of the cell and, therefore, influence morphogenesis and antibiotic production. We have surveyed the genome of S. coelicolor A3(2) to provide a thorough description of the carbohydrate uptake systems. Among 81 ATP-binding cassette (ABC) permeases that are present in the genome, we found 45 to encode a putative solute binding protein, an essential feature for carbohydrate permease function. Similarity analysis allowed the prediction of putative ABC systems for transport of cellobiose and cellotriose, α-glucosides, lactose, maltose, maltodextrins, ribose, sugar alcohols, xylose, and β-xylosides. A novel putative bifunctional protein composed of a substrate binding and a membrane-spanning moiety is likely to account for ribose or ribonucleoside uptake. Glucose may be incorporated by a proton-driven symporter of the major facilitator superfamily while a putative sodium-dependent permease of the solute-sodium symporter family may mediate uptake of galactose and a facilitator protein of the major intrinsic protein family may internalize glycerol. Of the predicted gene clusters, reverse transcriptase PCRs showed active gene expression in 8 of 11 systems. Together with the previously surveyed permeases of the phosphotransferase system that accounts for the uptake of fructose and N-acetylglucosamine, the genome of S. coelicolor encodes at least 53 potential carbohydrate uptake systems.

Microbiology ◽  
2010 ◽  
Vol 156 (11) ◽  
pp. 3478-3491 ◽  
Author(s):  
Matthew D. Servinsky ◽  
James T. Kiel ◽  
Nicole F. Dupuy ◽  
Christian J. Sund

Transcriptional analysis was performed on Clostridium acetobutylicum with the goal of identifying sugar-specific mechanisms for the transcriptional regulation of transport and metabolism genes. DNA microarrays were used to determine transcript levels from total RNA isolated from cells grown on media containing eleven different carbohydrates, including two pentoses (xylose, arabinose), four hexoses (glucose, mannose, galactose, fructose), four disaccharides (sucrose, lactose, maltose, cellobiose) and one polysaccharide (starch). Sugar-specific induction of many transport and metabolism genes indicates that these processes are regulated at the transcriptional level and are subject to carbon catabolite repression. The results show that C. acetobutylicum utilizes symporters and ATP-binding cassette (ABC) transporters for the uptake of pentose sugars, while disaccharides and hexoses are primarily taken up by phosphotransferase system (PTS) transporters and a gluconate : H+ (GntP) transporter. The transcription of some transporter genes was induced by specific sugars, while others were induced by a subset of the sugars tested. Sugar-specific transport roles are suggested, based on expression comparisons, for various transporters of the PTS, the ABC superfamily and members of the major facilitator superfamily (MFS), including the GntP symporter family and the glycoside-pentoside-hexuronide (GPH)-cation symporter family. Additionally, updates to the C. acetobutylicum genome annotation are proposed, including the identification of genes likely to encode proteins involved in the metabolism of arabinose and xylose via the pentose phosphate pathway.


2003 ◽  
Vol 185 (3) ◽  
pp. 929-937 ◽  
Author(s):  
Harald Nothaft ◽  
Stephan Parche ◽  
Annette Kamionka ◽  
Fritz Titgemeyer

ABSTRACT HPr, the histidine-containing phosphocarrier protein of the bacterial phosphotransferase system (PTS), serves multiple functions in carbohydrate uptake and carbon source regulation in low-G+C-content gram-positive bacteria and in gram-negative bacteria. To assess the role of HPr in the high-G+C-content gram-positive organism Streptomyces coelicolor, the encoding gene, ptsH, was deleted. The ptsH mutant BAP1 was impaired in fructose utilization, while growth on other carbon sources was not affected. Uptake assays revealed that BAP1 could not transport appreciable amounts of fructose, while the wild type showed inducible high-affinity fructose transport with an apparent Km of 2 μM. Complementation and reconstitution experiments demonstrated that HPr is indispensable for a fructose-specific PTS activity. Investigation of the putative fruKA gene locus led to identification of the fructose-specific enzyme II permease encoded by the fruA gene. Synthesis of HPr was not specifically enhanced in fructose-grown cells and occurred also in the presence of non-PTS carbon sources. Transcriptional analysis of ptsH revealed two promoters that are carbon source regulated. In contrast to what happens in other bacteria, glucose repression of glycerol kinase was still operative in a ptsH background, which suggests that HPr is not involved in general carbon regulation. However, fructose repression of glycerol kinase was lost in BAP1, indicating that the fructose-PTS is required for transduction of the signal. This study provides the first molecular genetic evidence of a physiological role of the PTS in S. coelicolor.


2009 ◽  
Vol 53 (11) ◽  
pp. 4673-4677 ◽  
Author(s):  
James J. Vecchione ◽  
Blair Alexander ◽  
Jason K. Sello

ABSTRACT Chloramphenicol, florfenicol, and thiamphenicol are used as antibacterial drugs in clinical and veterinary medicine. Two efflux pumps of the major facilitator superfamily encoded by the cmlR1 and cmlR2 genes mediate resistance to these antibiotics in Streptomyces coelicolor, a close relative of Mycobacterium tuberculosis. The transcription of both genes was observed by reverse transcription-PCR. Disruption of cmlR1 decreased the chloramphenicol MIC 1.6-fold, while disruption of cmlR2 lowered the MIC 16-fold. The chloramphenicol MIC of wild-type S. coelicolor decreased fourfold and eightfold in the presence of reserpine and Phe-Arg-β-naphthylamide, respectively. These compounds are known to potentiate the activity of some antibacterial drugs via efflux pump inhibition. While reserpine is known to potentiate drug activity against gram-positive bacteria, this is the first time that Phe-Arg-β-naphthylamide has been shown to potentiate drug activity against a gram-positive bacterium.


1998 ◽  
Vol 180 (3) ◽  
pp. 498-504 ◽  
Author(s):  
Ian T. Paulsen ◽  
Sylvie Chauvaux ◽  
Peter Choi ◽  
Milton H. Saier

ABSTRACT Insertional mutagenesis was conducted on Bacillus subtilis cells to screen for mutants resistant to catabolite repression. Three classes of mutants that were resistant to glucose-promoted but not mannitol-promoted catabolite repression were identified. Cloning and sequencing of the mutated genes revealed that the mutations occurred in the structural genes for (i) enzyme II of the phosphoenolpyruvate-glucose phosphotransferase (PtsG), (ii) antiterminator GlcT, which controls PtsG synthesis, and (iii) a previously uncharacterized carrier of the major facilitator superfamily, which we have designated GlcP. The last protein exhibits greatest sequence similarity to the fucose:H+ symporter ofEscherichia coli and the glucose/galactose:H+symporter of Brucella abortus. In a wild-type B. subtilis genetic background, theglcP::Tn10 mutation (i) partially but specifically relieved glucose- and sucrose-promoted catabolite repression, (ii) reduced the growth rate in minimal glucose medium, and (iii) reduced rates of [14C]glucose and [14C]methyl α-glucoside uptake. In a Δptsgenetic background no phenotype was observed, suggesting that expression of the glcP gene required a functional phosphotransferase system. When overproduced in a Δptsmutant of E. coli, GlcP could be shown to specifically transport glucose, mannose, 2-deoxyglucose and methyl α-glucoside with low micromolar affinities. Accumulation of the nonmetabolizable glucose analogs was demonstrated, and inhibitor studies suggested a dependency on the proton motive force. We conclude that B. subtilis possesses at least two distinct routes of glucose entry, both of which contribute to the phenomenon of catabolite repression.


2002 ◽  
Vol 68 (6) ◽  
pp. 2885-2892 ◽  
Author(s):  
Rosie E. Bradshaw ◽  
Deepak Bhatnagar ◽  
Rebecca J. Ganley ◽  
Carmel J. Gillman ◽  
Brendon J. Monahan ◽  
...  

ABSTRACT Homologs of aflatoxin biosynthetic genes have been identified in the pine needle pathogen Dothistroma pini. D. pini produces dothistromin, a difuranoanthraquinone toxin with structural similarity to the aflatoxin precursor versicolorin B. Previous studies with purified dothistromin suggest a possible role for this toxin in pathogenicity. By using an aflatoxin gene as a hybridization probe, a genomic D. pini clone was identified that contained four dot genes with similarity to genes in aflatoxin and sterigmatocystin gene clusters with predicted activities of a ketoreductase (dotA), oxidase (dotB), major facilitator superfamily transporter (dotC), and thioesterase (dotD). A D. pini dotA mutant was made by targeted gene replacement and shown to be severely impaired in dothistromin production, confirming that dotA is involved in dothistromin biosynthesis. Accumulation of versicolorin A (a precursor of aflatoxin) by the dotA mutant confirms that the dotA gene product is involved in an aflatoxin-like biosynthetic pathway. Since toxin genes have been found to be clustered in fungi in every case analyzed so far, it is speculated that the four dot genes may comprise part of a dothistromin biosynthetic gene cluster. A fifth gene, ddhA, is not a homolog of aflatoxin genes and could be at one end of the dothistromin cluster. These genes will allow comparative biochemical and genetic studies of the aflatoxin and dothistromin biosynthetic pathways and may also lead to new ways to control Dothistroma needle blight.


2004 ◽  
Vol 379 (2) ◽  
pp. 375-383 ◽  
Author(s):  
Patricia A. vanKUYK ◽  
Jasper A. DIDERICH ◽  
Andrew P. MacCABE ◽  
Oscar HERERRO ◽  
George J. G. RUIJTER ◽  
...  

A sugar-transporter-encoding gene, mstA, which is a member of the major facilitator superfamily, has been cloned from a genomic DNA library of the filamentous fungus Aspergillus niger. To enable the functional characterization of MSTA, a full-length cDNA was expressed in a Saccharomyces cerevisiae strain deficient in hexose uptake. Uptake experiments using 14C-labelled monosaccharides demonstrated that although able to transport d-fructose (Km, 4.5±1.0 mM), d-xylose (Km, 0.3±0.1 mM) and d-mannose (Km, 60±20 µM), MSTA has a preference for d-glucose (Km, 25±10 µM). pH changes associated with sugar transport indicate that MSTA catalyses monosaccharide/H+ symport. Expression of mstA in response to carbon starvation and upon transfer to poor carbon sources is consistent with a role for MSTA as a high-affinity transporter for d-glucose, d-mannose and d-xylose. Northern analysis has shown that mstA is subject to CreA-mediated carbon catabolite repression and pH regulation mediated by PacC. A. niger strains in which the mstA gene had been disrupted are phenotypically identical with isogenic reference strains when grown on 0.1–60 mM d-glucose, d-mannose, d-fructose or d-xylose. This indicates that A. niger possesses other transporters capable of compensating for the absence of MSTA.


2007 ◽  
Vol 189 (14) ◽  
pp. 5284-5292 ◽  
Author(s):  
Nancy L. McKenzie ◽  
Justin R. Nodwell

ABSTRACT The AbsA two-component signal transduction system, comprised of the sensor kinase AbsA1 and the response regulator AbsA2, acts as a negative regulator of antibiotic production in Streptomyces coelicolor, for which the phosphorylated form of AbsA2 (AbsA2∼P) is the agent of repression. In this study, we used chromatin immunoprecipitation to show that AbsA2 binds the promoter regions of actII-ORF4, cdaR, and redZ, which encode pathway-specific activators for actinorhodin, calcium-dependent antibiotic, and undecylprodigiosin, respectively. We confirm that these interactions also occur in vitro and that the binding of AbsA2 to each gene is enhanced by phosphorylation. Induced expression of actII-ORF4 and redZ in the hyperrepressive absA1 mutant (C542) brought about pathway-specific restoration of actinorhodin and undecylprodigiosin production, respectively. Our results suggest that AbsA2∼P interacts with as many as four sites in the region that includes the actII-ORF4 promoter. These data suggest that AbsA2∼P inhibits antibiotic production by directly interfering with the expression of pathway-specific regulators of antibiotic biosynthetic gene clusters.


2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
Author(s):  
Olga Tsypik ◽  
Roman Makitrynskyy ◽  
Agnieszka Bera ◽  
Lijiang Song ◽  
Wolfgang Wohlleben ◽  
...  

Here we report functional characterization of the Streptomyces coelicolor M145 gene SCO1678, which encodes a GntR-like regulator of the FadR subfamily. Bioinformatic analysis suggested that SCO1678 is part of putative operon (gnt) involved in gluconate metabolism. Combining the results of SCO1678 knockout, transcriptional analysis of gnt operon, and Sco1678 protein-DNA electromobility shift assays, we established that Sco1678 protein controls the gluconate operon. It does so via repression of its transcription from a single promoter located between genes SCO1678 and SCO1679. The knockout also influenced, in a medium-dependent manner, the production of secondary metabolites by S. coelicolor. In comparison to the wild type, on gluconate-containing minimal medium, the SCO1678 mutant produced much less actinorhodin and accumulated a yellow-colored pigment, likely to be the cryptic polyketide coelimycin. Possible links between gluconate metabolism and antibiotic production are discussed.


2019 ◽  
Author(s):  
Jana K Schniete ◽  
Richard Reumerman ◽  
Leena Kerr ◽  
Nicholas P Tucker ◽  
Iain S Hunter ◽  
...  

AbstractBackgroundStreptomycete bacteria are prolific producers of specialised metabolites, many of which have clinically relevant bioactivity. A striking feature of their genomes is the expansion of gene families that encode the same enzymatic function. Genes that undergo expansion events, either by horizontal gene transfer or duplication, can have a range of fates: genes can be lost, or they can undergo neo-functionalisation or sub-functionalisation. To test whether expanded gene families in Streptomyces exhibit differential expression, an RNA-Seq approach was used to examine cultures of wild-type Streptomyces coelicolor grown with either glucose or tween as the sole carbon source.ResultsRNA-Seq analysis showed that two-thirds of genes within expanded gene families show transcriptional differences when strains were grown on tween compared to glucose. In addition, expression of specialised metabolite gene clusters (actinorhodin, isorenieratane, coelichelin and a cryptic NRPS) was also influenced by carbon source.ConclusionsExpression of genes encoding the same enzymatic function had transcriptional differences when grown on different carbon sources. This transcriptional divergence enables partitioning to function under different physiological conditions. These approaches can inform metabolic engineering of industrial Streptomyces strains and may help develop cultivation conditions to activate the so-called silent biosynthetic gene clusters.


2005 ◽  
Vol 71 (5) ◽  
pp. 2452-2459 ◽  
Author(s):  
Alessandra S. Eustáquio ◽  
Bertolt Gust ◽  
Ute Galm ◽  
Shu-Ming Li ◽  
Keith F. Chater ◽  
...  

ABSTRACT A method was developed for the heterologous expression of biosynthetic gene clusters in different Streptomyces strains and for the modification of these clusters by single or multiple gene replacements or gene deletions with unprecedented speed and versatility. λ-Red-mediated homologous recombination was used for genetic modification of the gene clusters, and the attachment site and integrase of phage φC31 were employed for the integration of these clusters into the heterologous hosts. This method was used to express the gene clusters of the aminocoumarin antibiotics novobiocin and clorobiocin in the well-studied strains Streptomyces coelicolor and Streptomyces lividans, which, in contrast to the natural producers, can be easily genetically manipulated. S. coelicolor M512 derivatives produced the respective antibiotic in yields comparable to those of natural producer strains, whereas S. lividans TK24 derivatives were at least five times less productive. This method could also be used to carry out functional investigations. Shortening of the cosmids' inserts showed which genes are essential for antibiotic production.


Sign in / Sign up

Export Citation Format

Share Document