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  • genes
  • The control of DNA-supercoiling in S. pneumoniae occurs mainly via the regulation of topoisomerase gene transcription: relaxation triggers the up-regulation of gyrase and the down-regulation of topoisomerases I and IV, while hypernegative supercoiling down-regulates the expression of topoisomerase I. Relaxation affects 13% of the genome, with the majority of the genes affected located in 15 domains. (frontiersin.org)
  • In September, 2013 the studies of topoisomerase inhibitors like fluoroquinolones as they relate to Autism commenced with an article in Nature entitled " Topoisomerases facilitate transcription of long genes linked to autism . (collective-evolution.com)
  • An article published in September, 2013 in Nature entitled " Topoisomerases facilitate transcription of long genes linked to autism " noted that topoisomerase inhibitors can adversely affect gene expression and, "topoisomerases facilitate the expression of a large number of ASD (Autism Spectrum Disorder) candidate genes, including many that are long and that are thought to have large effects on ASD pathology. (collective-evolution.com)
  • It should be noted that the specific drug studied in "Topoisomerases facilitate transcription of long genes linked to autism" is Topotecan, not fluoroquinolones. (collective-evolution.com)
  • fluorine
  • The majority of drugs in clinical use are actually quinoline derivatives that belong to the subset fluoroquinolones, which have a fluorine atom attached to the central ring system, often at the C-6 or C-7 position. (wikipedia.org)
  • inhibitory
  • EGCG, genistein, quercetin, resveratrol) possess strong topoisomerase inhibitory properties affecting both types of enzymes. (wikipedia.org)
  • Fleroxacin and other fluoroquinolones, are known to trigger seizures or lower the seizure threshold, due to their inhibitory activity on GABA receptor binding. (wikipedia.org)
  • molecules
  • Topoisomerase IV: helps separate the daughter DNA molecules. (brainscape.com)
  • The number of superhelical turns introduced into an initially relaxed circular DNA has been calculated to be approximately equal to the number of ATP molecules hydrolyzed by gyrase. (wikipedia.org)
  • Therefore, it can be suggested that two ATP molecules are hydrolyzed per cycle of reaction by gyrase, leading to the introduction of a linking difference of -2. (wikipedia.org)
  • Gyrase is present in prokaryotes and some eukaryotes, but the enzymes are not entirely similar in structure or sequence, and have different affinities for different molecules. (wikipedia.org)
  • renal
  • In contrast to other fluoroquinolones, renal clearance accounts for only 5% of the removal of difloxacin from the canine system, which makes it an attractive choice for dogs with compromised renal function. (wikipedia.org)
  • strands
  • Topoisomerase inhibitors are chemical compounds that block the action of topoisomerase (topoisomerase I and II), which are enzymes that control the changes in DNA structure by catalyzing the breaking and rejoining of the phosphodiester backbone of DNA strands during the normal cell cycle. (wikipedia.org)
  • Achilles
  • Tendinitis and rupture, usually of the Achilles tendon, are a class-effects of the fluoroquinolones, most frequently reported with pefloxacin. (wikipedia.org)
  • The most severe form of tendonopathy associated with fluoroquinolone administration is tendon rupture, which in the great majority of cases involves the Achilles tendon. (wikipedia.org)
  • drugs
  • Due to sickle-cell disease patients' being at increased risk for developing osteomyelitis from the Salmonella genus, fluoroquinolones are the "drugs of choice" due to their ability to enter bone tissue without chelating it, as tetracyclines are known to do. (wikipedia.org)
  • susceptible
  • The MIC values of all fluoroquinolones showed a bimodal distribution (susceptible strain and less susceptible strain). (pubmedcentralcanada.ca)
  • 53) were less susceptible to fluoroquinolones. (pubmedcentralcanada.ca)
  • Aerobic Gram-positive microorganisms: Staphylococcus aureus (methicillin-susceptible strains) Streptococcus pneumoniae (penicillin-susceptible strains) Streptococcus pyogenes Aerobic Gram-negative microorganisms Citrobacter koseri (Citrobacter diversus) Enterobacter aerogenes Escherichia coli Haemophilus influenzae Klebsiella pneumoniae Neisseria gonorrhoeae Proteus mirabilis Pseudomonas aeruginosa Other microorganisms: Chlamydia trachomatis In general, fluoroquinolones are well tolerated, with most side-effects being mild to moderate. (wikipedia.org)
  • mechanisms
  • There continues to be considerable debate as to whether or not this DNA damage is to be considered one of the mechanisms of action concerning the severe adverse reactions experienced by some patients following fluoroquinolone therapy. (wikipedia.org)
  • Levofloxacin
  • The overall frequency of fluoroquinolone-associated Achilles tendon rupture in patients treated with ciprofloxacin or levofloxacin has been estimated at 17 per 100,000 treatments. (wikipedia.org)
  • Prolongation of the QT interval can lead to torsades de pointes, a life-threatening arrhythmia, but in practice this appears relatively uncommon in part because the most widely prescribed fluoroquinolones (ciprofloxacin and levofloxacin) only minimally prolong the QT interval. (wikipedia.org)
  • strains
  • Fluoroquinolone-resistant strains of Shigella dysenteriae type1 and Shigella flexneri type 2a emerged in India during 2002 and 2003, respectively. (microbiologyresearch.org)
  • Aerobic Gram-positive microorganisms: Staphylococcus aureus (methicillin-susceptible strains) Streptococcus pneumoniae (penicillin-susceptible strains) Streptococcus pyogenes Aerobic Gram-negative microorganisms Citrobacter koseri (Citrobacter diversus) Enterobacter aerogenes Escherichia coli Haemophilus influenzae Klebsiella pneumoniae Neisseria gonorrhoeae Proteus mirabilis Pseudomonas aeruginosa Other microorganisms: Chlamydia trachomatis In general, fluoroquinolones are well tolerated, with most side-effects being mild to moderate. (wikipedia.org)
  • WARNINGS
  • Partly as a result of the efforts of Public Citizen, in 2008 the U.S. FDA ordered boxed warnings on all fluoroquinolones, advising consumers of an enhanced risk of tendon damage. (wikipedia.org)
  • novobiocin
  • X-ray crystallographic studies have found that the drug-receptor complex of Novobiocin and DNA Gyrase shows that ATP and Novobiocin have overlapping binding sites on the gyrase molecule. (wikipedia.org)
  • tendon
  • The most severe form of tendonopathy associated with fluoroquinolone administration is tendon rupture, which in the great majority of cases involves the Achilles tendon. (wikipedia.org)
  • Tendon damage may manifest during, as well as up to a year after fluoroquinolone therapy has been completed. (wikipedia.org)
  • Tablets
  • The FDA wrote: "An FDA safety review has shown that fluoroquinolones when used systemically (i.e. tablets, capsules, and injectable) are associated with disabling and potentially permanent serious side effects that can occur together. (wikipedia.org)
  • bind
  • Norfloxacin does not bind to DNA gyrase but does bind to the substrate DNA. (wikipedia.org)
  • Experiments have demonstrated that positive supercoiled DNA provides a sharp DNA bend in the first bound DNA segment, which allows the topoisomerase to bind successfully and therefore carry on its enzymatic reaction to the following segment in an specific inside-to-outside matter. (wikipedia.org)
  • type
  • The unlinking of catenanes is performed by type IIA topoisomerases, which were recently found to be more efficient unlinking positive supercoiled DNA.The conformational properties of negative vs. positive supercoiled catenanes affects their features in respect to their corresponding enzymatic reaction catalyzed by topoisomerases. (wikipedia.org)