scholarly journals GPI0363 inhibits the interaction of RNA polymerase with DNA in Staphylococcus aureus

RSC Advances ◽  
2019 ◽  
Vol 9 (65) ◽  
pp. 37889-37894 ◽  
Author(s):  
Atmika Paudel ◽  
Suresh Panthee ◽  
Hiroshi Hamamoto ◽  
Kazuhisa Sekimizu
Keyword(s):  
Staphylococcus Aureus ◽  
Rna Polymerase ◽  
Mode Of Action ◽  
Distinct Mode

GPI0363 has a distinct mode of action via SigA and is active against bacteria resistant to clinically used RNAP inhibitors.

scholarly journals In Vitro Evaluation of CBR-2092, a Novel Rifamycin-Quinolone Hybrid Antibiotic: Studies of the Mode of Action in Staphylococcus aureus

2008 ◽  
Vol 52 (7) ◽  
pp. 2313-2323 ◽  
Author(s):  
Gregory T. Robertson ◽  
Eric J. Bonventre ◽  
Timothy B. Doyle ◽  
Qun Du ◽  
Leonard Duncan ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Rna Polymerase ◽  
Mode Of Action ◽  
Bacterial Infections ◽  
Dna Gyrase ◽  
Topoisomerase Iv ◽  
Dna Topoisomerase ◽  
Resistant Variant ◽  
Proven Efficacy

ABSTRACT Rifamycins have proven efficacy in the treatment of persistent bacterial infections. However, the frequency with which bacteria develop resistance to rifamycin agents restricts their clinical use to antibiotic combination regimens. In a program directed toward the synthesis of rifamycins with a lower propensity to elicit resistance development, a series of compounds were prepared that covalently combine rifamycin and quinolone pharmacophores to form stable hybrid antibacterial agents. We describe mode-of-action studies with Staphylococcus aureus of CBR-2092, a novel hybrid that combines the rifamycin SV and 4H-4-oxo-quinolizine pharmacophores. In biochemical studies, CBR-2092 exhibited rifampin-like potency as an inhibitor of RNA polymerase, was an equipotent (balanced) inhibitor of DNA gyrase and DNA topoisomerase IV, and retained activity against a prevalent quinolone-resistant variant. Macromolecular biosynthesis studies confirmed that CBR-2092 has rifampin-like effects on RNA synthesis in rifampin-susceptible strains and quinolone-like effects on DNA synthesis in rifampin-resistant strains. Studies of mutant strains that exhibited reduced susceptibility to CBR-2092 further substantiated RNA polymerase as the primary cellular target of CBR-2092, with DNA gyrase and DNA topoisomerase IV being secondary and tertiary targets, respectively, in strains exhibiting preexisting rifampin resistance. In contrast to quinolone comparator agents, no strains with altered susceptibility to CBR-2092 were found to exhibit changes consistent with altered efflux properties. The combined data indicate that CBR-2092 may have potential utility in monotherapy for the treatment of persistent S. aureus infections.

scholarly journals The Phosphoenolpyruvate:Sugar Phosphotransferase System Is Involved in Sensitivity to the Glucosylated Bacteriocin Sublancin

2015 ◽  
Vol 59 (11) ◽  
pp. 6844-6854 ◽  
Author(s):  
C. V. Garcia De Gonzalo ◽  
E. L. Denham ◽  
R. A. T. Mars ◽  
J. Stülke ◽  
W. A. van der Donk ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Mechanism Of Action ◽  
Mode Of Action ◽  
Phosphotransferase System ◽  
Content Type ◽  
Gram Positive Bacteria ◽  
Distinct Mechanism ◽  
Genomic Studies ◽  
Increased Sensitivity ◽  
Bacterial Sensitivity

ABSTRACTThe mode of action of a group of glycosylated antimicrobial peptides known as glycocins remains to be elucidated. In the current study of one glycocin, sublancin, we identified the phosphoenolpyruvate:sugar phosphotransferase system (PTS) ofBacillusspecies as a key player in bacterial sensitivity. Sublancin kills several Gram-positive bacteria, such asBacillusspecies andStaphylococcus aureus, including methicillin-resistantS. aureus(MRSA). Unlike other classes of bacteriocins for which the PTS is involved in their mechanism of action, we show that the addition of PTS-requiring sugars leads to increased resistance rather than increased sensitivity, suggesting that sublancin has a distinct mechanism of action. Collectively, our present mutagenesis and genomic studies demonstrate that the histidine-containing phosphocarrier protein (HPr) and domain A of enzyme II (PtsG) in particular are critical determinants for bacterial sensitivity to sublancin.

scholarly journals A Mutation of RNA Polymerase β′ Subunit (RpoC) Converts Heterogeneously Vancomycin-Intermediate Staphylococcus aureus (hVISA) into “Slow VISA”

2015 ◽  
Vol 59 (7) ◽  
pp. 4215-4225 ◽  
Author(s):  
Miki Matsuo ◽  
Tomomi Hishinuma ◽  
Yuki Katayama ◽  
Keiichi Hiramatsu
Keyword(s):  
Staphylococcus Aureus ◽  
Cell Wall ◽  
Rna Polymerase ◽  
Stringent Response ◽  
Whole Genome ◽  
Multicopy Plasmid ◽  
Β Subunit ◽  
Whole Genome Analysis ◽  
Content Type ◽  
Peptidoglycan Biosynthesis

ABSTRACTVarious mutations in therpoBgene, which encodes the RNA polymerase β subunit, are associated with increased vancomycin (VAN) resistance in vancomycin-intermediateStaphylococcus aureus(VISA) and heterogeneously VISA (hVISA) strains. We reported thatrpoBmutations are also linked to the expression of the recently found “slow VISA” (sVISA) phenotype (M. Saito, Y. Katayama, T. Hishinuma, A. Iwamoto, Y. Aiba, K Kuwahara-Arai, L. Cui, M. Matsuo, N. Aritaka, and K. Hiramatsu, Antimicrob Agents Chemother 58:5024–5035, 2014,http://dx.doi.org/10.1128/AAC.02470-13). Because RpoC and RpoB are components of RNA polymerase, we examined the effect of therpoC(P440L) mutation on the expression of the sVISA phenotype in the Mu3fdh2*V6-5 strain (V6-5), which was derived from a previously reported hVISA strain with the VISA phenotype. V6-5 had an extremely prolonged doubling time (DT) (72 min) and high vancomycin MIC (16 mg/liter). However, the phenotype of V6-5 was unstable, and the strain frequently reverted to hVISA with concomitant loss of low growth rate, cell wall thickness, and reduced autolysis. Whole-genome sequencing of phenotypic revertant strain V6-5-L1 and comparison with V6-5 revealed a second mutation, F562L, inrpoC. Introduction of the wild-type (WT)rpoCgene using a multicopy plasmid resolved the sVISA phenotype of V6-5, indicating that therpoC(P440L) mutant expressed the sVISA phenotype in hVISA. To investigate the mechanisms of resistance in the sVISA strain, we independently isolated an additional 10 revertants to hVISA and VISA. In subsequent whole-genome analysis, we identified compensatory mutations in the genes of three distinct functional categories: therpoCgene itself as regulatory mutations, peptidoglycan biosynthesis genes, andrelQ, which is involved in the stringent response. It appears that therpoC(P440L) mutation causes the sVISA phenotype by augmenting cell wall peptidoglycan synthesis and through the control of the stringent response.

Mode of action of the alpha toxin of Staphylococcus aureus

1970 ◽  
Vol 16 (1) ◽  
pp. 47-50 ◽  
Author(s):  
G. M. Wiseman ◽  
J. D. Caird
Keyword(s):  
Staphylococcus Aureus ◽  
Proteolytic Activity ◽  
Mode Of Action ◽  
Differential Sensitivity ◽  
Aureus Strain ◽  
Red Cell ◽  
Alpha Toxin ◽  
Reaction Products ◽  
Phenol Reagent

Rabbit erythrocytes treated with the alpha toxin of Staphylococcus aureus, strain "Wood-46", liberate substances which contain nitrogen, absorb at 280 mμ, and react with Folin phenol reagent. The susceptibility of different erythrocyte species to alpha toxin is correlated with (a) the quantity of reaction products released by toxin from the cells and (b) the degree of natural proteolytic activity possessed by the cells. Alpha toxin was, however, without effect upon albumin, fibrinogen, casein, and hemoglobin even when these proteins had been denatured with urea. In view of the evidence, it is suggested that the toxin is secreted by the Staphylococcus as an inactive protease which must be activated by another protease. The degree of activity of this protease in various red cell species would explain their differential sensitivity to alpha toxin.

scholarly journals RNA Polymerase Inhibitors with Activity against Rifampin-Resistant Mutants of Staphylococcus aureus

2000 ◽  
Vol 44 (11) ◽  
pp. 3163-3166 ◽  
Author(s):  
Alexander O'Neill ◽  
Brunello Oliva ◽  
Christopher Storey ◽  
Anthony Hoyle ◽  
Colin Fishwick ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Drug Development ◽  
Rna Polymerase ◽  
Gene Mutations ◽  
Β Subunit ◽  
Polymerase Inhibitors ◽  
Resistant Mutants ◽  
Sorangicin A

ABSTRACT A collection of rifampin-resistant mutants of Staphylococcus aureus with characterized RNA polymerase β-subunit (rpoB) gene mutations was cross-screened against a number of other RNA polymerase inhibitors to correlate susceptibility with specific rpoB genotypes. The rpoB mutants were cross-resistant to streptolydigin and sorangicin A. In contrast, thiolutin, holomycin, corallopyronin A, and ripostatin A retained activity against the rpoB mutants. The second group of inhibitors may be of interest as drug development candidates.

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