The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Pietro E Varaldo - One of the best experts on this subject based on the ideXlab platform.
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streptococcus pneumoniae transposon tn1545 tn6003 changes to tn6002 due to spontaneous excision in circular form of the erm b and apha3 containing macrolide aminoglycoside Streptothricin mas element
2012Co-Authors: Claudio Palmieri, Marina Mingoia, Orietta Massidda, Eleonora Giovanetti, Pietro E VaraldoAbstract:The macrolide-aminoglycoside-Streptothricin (MAS) element, an ∼4.2-kb insertion containing erm(B) and aphA3 resistance determinants, distinguishes Streptococcus pneumoniae transposon Tn1545/Tn6003 from Tn6002. Here, it is shown to be an unstable genetic element that, although it lacks recombinase genes, can exploit long, erm(B)-containing direct repeats acting as att sites for spontaneous excision that may result in loss. Consequent to excision, which is RecA independent, Tn1545/Tn6003 changes to Tn6002. In pneumococcal populations harboring Tn1545/Tn6003, the latter appears to coexist with Tn6002.
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streptococcus suis an emerging drug resistant animal and human pathogen
2011Co-Authors: Claudio Palmieri, Pietro E Varaldo, Bruna FacinelliAbstract:Streptococcus suis, a major porcine pathogen, has been receiving growing attention not only for its role in severe and increasingly reported infections in humans, but also for its involvement in drug resistance. Recent studies and the analysis of sequenced genomes have been providing important insights into the S. suis resistome, and have resulted in the identification of resistance determinants for tetracyclines, macrolides, aminoglycosides, chloramphenicol, antifolate drugs, Streptothricin, and cadmium salts. Resistance gene-carrying genetic elements described so far include integrative and conjugative elements, transposons, genomic islands, phages, and chimeric elements. Some of these elements are similar to those reported in major streptococcal pathogens such as Streptococcus pyogenes, Streptococcus pneumoniae, and Streptococcus agalactiae and share the same chromosomal insertion sites. The available information strongly suggests that S. suis is an important antibiotic resistance reservoir that can contribute to the spread of resistance genes to the above-mentioned streptococci. S. suis is thus a paradigmatic example of possible intersections between animal and human resistomes.
Jean Brevet - One of the best experts on this subject based on the ideXlab platform.
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Streptothricin resistance as a novel selectable marker for transgenic plant cells
2000Co-Authors: J Jelenska, Erhard Tietze, Jacques Tempe, Jean BrevetAbstract:Streptothricins are known as antimicrobial agents produced by Streptomyces spp. Bacterial resistance to Streptothricin is mediated by specific enzymes exhibiting an acetyltransferase activity which renders the drug non-toxic for bacteria. The nucleotide sequence of several Streptothricin resistance genes from bacteria have been described. Certain cells of eukaryotic parasites (such as Ustilago maydis or Leishmania spp.) are sensitive to Streptothricin and the introduction of the bacterial resistance gene sat2 renders them resistant. We show that numerous species of plants are sensitive to low concentrations of Streptothricin. Moreover, introduction of the bacterial resistance gene sat3 under the control of the 35S cauliflower mosaic virus promoter protects these cells from the toxic action of Streptothricin. Therefore, sat3-mediated Streptothricin resistance appears to be a promising selective marker for genetic manipulation of plant cells.
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nucleotide sequence of the bacterial Streptothricin resistance gene sat3
1995Co-Authors: Erhard Tietze, Jean BrevetAbstract:The nucleotide sequence of the sat3 gene which encodes resistance of enteric bacteria to the antibiotic Streptothricin is reported. A protein with a molecular mass of about 23 kDa is expressed from this gene. The sat3 gene is not obviously related to any one of the Streptothricin resistance determinants identified so far among Gram-negative or Gram-positive bacteria.
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The trimethoprim resistance transposon Tn7 contains a cryptic Streptothricin resistance gene.
1991Co-Authors: Erhard Tietze, Jean BrevetAbstract:The transposon Tn7 codes for a trimethoprim resistance and for a streptomycin/spectinomycin resistance function of the bacterial host cells. Cloning of a restriction fragment of Tn7 into the vector plasmid pUC19 reveals the presence in Tn7 of an additional potential resistance determinant. A Streptothricin resistance gene, which appears cryptic in the original Tn7 context becomes activated in the recombinant plasmid upon supplying the promoter function of the lacZ system of pUC19. These results together with previously published sequence data further disclose the modular character in the resistance gene regions of Tn7-like transposons.
Claudio Palmieri - One of the best experts on this subject based on the ideXlab platform.
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streptococcus pneumoniae transposon tn1545 tn6003 changes to tn6002 due to spontaneous excision in circular form of the erm b and apha3 containing macrolide aminoglycoside Streptothricin mas element
2012Co-Authors: Claudio Palmieri, Marina Mingoia, Orietta Massidda, Eleonora Giovanetti, Pietro E VaraldoAbstract:The macrolide-aminoglycoside-Streptothricin (MAS) element, an ∼4.2-kb insertion containing erm(B) and aphA3 resistance determinants, distinguishes Streptococcus pneumoniae transposon Tn1545/Tn6003 from Tn6002. Here, it is shown to be an unstable genetic element that, although it lacks recombinase genes, can exploit long, erm(B)-containing direct repeats acting as att sites for spontaneous excision that may result in loss. Consequent to excision, which is RecA independent, Tn1545/Tn6003 changes to Tn6002. In pneumococcal populations harboring Tn1545/Tn6003, the latter appears to coexist with Tn6002.
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streptococcus suis an emerging drug resistant animal and human pathogen
2011Co-Authors: Claudio Palmieri, Pietro E Varaldo, Bruna FacinelliAbstract:Streptococcus suis, a major porcine pathogen, has been receiving growing attention not only for its role in severe and increasingly reported infections in humans, but also for its involvement in drug resistance. Recent studies and the analysis of sequenced genomes have been providing important insights into the S. suis resistome, and have resulted in the identification of resistance determinants for tetracyclines, macrolides, aminoglycosides, chloramphenicol, antifolate drugs, Streptothricin, and cadmium salts. Resistance gene-carrying genetic elements described so far include integrative and conjugative elements, transposons, genomic islands, phages, and chimeric elements. Some of these elements are similar to those reported in major streptococcal pathogens such as Streptococcus pyogenes, Streptococcus pneumoniae, and Streptococcus agalactiae and share the same chromosomal insertion sites. The available information strongly suggests that S. suis is an important antibiotic resistance reservoir that can contribute to the spread of resistance genes to the above-mentioned streptococci. S. suis is thus a paradigmatic example of possible intersections between animal and human resistomes.
Erhard Tietze - One of the best experts on this subject based on the ideXlab platform.
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Streptothricin resistance as a novel selectable marker for transgenic plant cells
2000Co-Authors: J Jelenska, Erhard Tietze, Jacques Tempe, Jean BrevetAbstract:Streptothricins are known as antimicrobial agents produced by Streptomyces spp. Bacterial resistance to Streptothricin is mediated by specific enzymes exhibiting an acetyltransferase activity which renders the drug non-toxic for bacteria. The nucleotide sequence of several Streptothricin resistance genes from bacteria have been described. Certain cells of eukaryotic parasites (such as Ustilago maydis or Leishmania spp.) are sensitive to Streptothricin and the introduction of the bacterial resistance gene sat2 renders them resistant. We show that numerous species of plants are sensitive to low concentrations of Streptothricin. Moreover, introduction of the bacterial resistance gene sat3 under the control of the 35S cauliflower mosaic virus promoter protects these cells from the toxic action of Streptothricin. Therefore, sat3-mediated Streptothricin resistance appears to be a promising selective marker for genetic manipulation of plant cells.
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nucleotide sequence of the bacterial Streptothricin resistance gene sat3
1995Co-Authors: Erhard Tietze, Jean BrevetAbstract:The nucleotide sequence of the sat3 gene which encodes resistance of enteric bacteria to the antibiotic Streptothricin is reported. A protein with a molecular mass of about 23 kDa is expressed from this gene. The sat3 gene is not obviously related to any one of the Streptothricin resistance determinants identified so far among Gram-negative or Gram-positive bacteria.
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distribution of Streptothricin acetyltransferase encodi determinants among environmental bacteria
1993Co-Authors: Kornelia Smalla, Erhard Tietze, Rita Prager, M Isemann, R Pukall, J D Van Elsas, Helmut TschäpeAbstract:In this paper we report about a screening for Streptothricin- (St)-resistant phenotypes and genotypes among environmental bacteria from a St virgin area. St-resistant bacteria were isolated from river water, sewage, manure and soil by selective plating. The resistance quotient was typical of an area without selective pressure. The occurrence of Streptothricin acetyltransferase-encoding determinants and their localization on a Tn7-like transposon was tested by the application of a set of gene probes. Sat genes could be detected in 22.5% of the tested St-resistant bacteria but in 100% of the checked Enterobacteriaceae. However, we could not detect sat genes in St-resistant bacteria from soil samples. Surprisingly the sat genes were found to be located on conjugative or mobilizable plasmids for a rather high number of strains. The determined plasmid species and their restriction patterns showed a high degree of similarities to those observed from an area of strong selective pressure.
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The trimethoprim resistance transposon Tn7 contains a cryptic Streptothricin resistance gene.
1991Co-Authors: Erhard Tietze, Jean BrevetAbstract:The transposon Tn7 codes for a trimethoprim resistance and for a streptomycin/spectinomycin resistance function of the bacterial host cells. Cloning of a restriction fragment of Tn7 into the vector plasmid pUC19 reveals the presence in Tn7 of an additional potential resistance determinant. A Streptothricin resistance gene, which appears cryptic in the original Tn7 context becomes activated in the recombinant plasmid upon supplying the promoter function of the lacZ system of pUC19. These results together with previously published sequence data further disclose the modular character in the resistance gene regions of Tn7-like transposons.
Jorge C Escalantesemerena - One of the best experts on this subject based on the ideXlab platform.
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insights into the function of the n acetyltransferase sata that detoxifies Streptothricin in bacillus subtilis and bacillus anthracis
2019Co-Authors: Rachel M Burckhardt, Jorge C EscalantesemerenaAbstract:Acylation of epsilon amino groups of lysyl side chains is a widespread modification of proteins and small molecules in cells of all three domains of life. Recently, we showed that Bacillus subtilis and Bacillus anthracis encode the GCN5-related N-acetyltransferase (GNAT) SatA that can acetylate and inactivate Streptothricin, which is a broad-spectrum antibiotic produced by actinomycetes in the soil. To determine functionally relevant residues of B. subtilis SatA (BsSatA), a mutational screen was performed, highlighting the importance of a conserved area near the C terminus. Upon inspection of the crystal structure of the B. anthracis Ames SatA (BaSatA; PDB entry 3PP9), this area appears to form a pocket with multiple conserved aromatic residues; we hypothesized this region contains the Streptothricin-binding site. Chemical and site-directed mutagenesis was used to introduce missense mutations into satA, and the functionality of the variants was assessed using a heterologous host (Salmonella enterica). Results of isothermal titration calorimetry experiments showed that residue Y164 of BaSatA was important for binding Streptothricin. Results of size exclusion chromatography analyses showed that residue D160 was important for dimerization. Together, these data advance our understanding of how SatA interacts with Streptothricin.IMPORTANCE This work provides insights into how an abundant antibiotic found in soil is bound to the enzyme that inactivates it. This work identifies residues for the binding of the antibiotic and probes the contributions of substituting side chains for those in the native protein, providing information regarding hydrophobicity, size, and flexibility of the antibiotic binding site.
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in bacillus subtilis the sata formerly yyar acetyltransferase detoxifies Streptothricin via lysine acetylation
2017Co-Authors: Rachel M Burckhardt, Jorge C EscalantesemerenaAbstract:Soil is a complex niche, where survival of microorganisms is at risk due to the presence of antimicrobial agents. Many microbes chemically modify cytotoxic compounds to block their deleterious effects. Streptothricin is a broad-spectrum antibiotic produced by streptomycetes that affects Gram-positive and Gram-negative bacteria alike. Here we identify the SatA (for Streptothricin acetyltransferase A, formerly YyaR) enzyme of Bacillus subtilis as the mechanism used by this soil bacterium to detoxify Streptothricin. B. subtilis strains lacking satA were susceptible to Streptothricin. Ectopic expression of satA+ restored Streptothricin resistance to B. subtilissatA (BsSatA) strains. Purified BsSatA acetylated Streptothricin in vitro at the expense of acetyl-coenzyme A (acetyl-CoA). A single acetyl moiety transferred onto Streptothricin by SatA blocked the toxic effects of the antibiotic. SatA bound Streptothricin with high affinity (Kd [dissociation constant] = 1 μM), and did not bind acetyl-CoA in the absence of Streptothricin. Expression of B. subtilissatA+ in Salmonella enterica conferred Streptothricin resistance, indicating that SatA was necessary and sufficient to detoxify Streptothricin. Using this heterologous system, we showed that the SatA homologue from Bacillus anthracis also had Streptothricin acetyltransferase activity. Our data highlight the physiological relevance of lysine acetylation for the survival of B. subtilis in the soil.IMPORTANCE Experimental support is provided for the functional assignment of gene products of the soil-dwelling bacilli Bacillus subtilis and Bacillus anthracis This study focuses on one enzyme that is necessary and sufficient to block the cytotoxic effects of a common soil antibiotic. The enzyme alluded to is a member of a family of proteins that are broadly distributed in all domains of life but poorly studied in B. subtilis and B. anthracis The initial characterization of the enzyme provides insights into its mechanism of catalysis.