Supercoiling is important in a number of biological processes, such as compacting DNA, and by regulating access to the genetic code, DNA supercoiling strongly affects DNA metabolism and possibly gene expression. Additionally, certain enzymes such as topoisomerases are able to change DNA topology to facilitate functions such as DNA replication or transcription. Dose of plaquenil for rheumatoid arthritis Hydroxychloroquine and lupus pregnancy Is chloroquine safe in early pregnancy Determining whether a plasmid contains positively or negatively supercoiled DNA is possible, thanks to an agarose gel containing an intercalating agent known to positively supercoil DNA, such as chloroquine. The speed of migration of the topoisomers varies in a characteristic way in the presence and absence of the agent. Effect of ethidium binding and superhelix density on the supercoiling free energy and torsion and bending constants of p30δ DNA. Biophysical Chemistry 1994, 52 3, 191-218. Addition of 10 μg/ml chloroquine salt solution to both the gel and running buffer allows relaxed circular DNA to migrate further while supercoiled circular DNA is retarded in the gel and remains. Adding or subtracting twists, as some enzymes can do, imposes strain. In a "relaxed" double-helical segment of B-DNA, the two strands twist around the helical axis once every 10.4–10.5 base pairs of sequence. Chloroquine dna supercoiling Hyper-Negative Template DNA Supercoiling During., Interaction of chloroquine with linear and supercoiled. Is plaquenil an immunosuppressantPlaquenil ask doctorPlaquenil generic alternatives Note that all the DNA samples appeared positively supercoiled at this chloroquine concentration 7 μg/ml, which is higher than that used in Fig. 1. Therefore, as negative supercoils are added, the DNA mobility decreases. A transition in colony-forming rates and in negative supercoiling occurred between 50 and 100 mM NaCl lanes 3 and 4. Plasmid DNA Supercoiling and Survival in Long-Term Cultures of.. Acquisition of fluoroquinolone resistance leads to increased biofilm.. Analysis of DNA supercoiling induced by DNA-protein.. As the global supercoiling state of the chlamydial plasmid changed more than twofold between 24 and 46 hpi, we isolated the native plasmid at additional time points during the developmental cycle to determine the temporal pattern of DNA supercoiling in Chlamydia. We electrophoresed the plasmids on agarose gels at different chloroquine concentrations to best resolve the topoisomer bands. Chloroquine, a DNA intercalating drug, unwinds the DNA, decreasing the levels of negative supercoiling. Following this in vivo topological perturbation, within minutes DNA gyrase decreases DNA linking number producing more negatively supercoiled DNA topoisomers. Following the removal of the drug from cells. In the presence of the DNA intercalator chloroquine 5 μg/ml, this DNA was largely relaxed and migrated during agarose gel electrophoresis as if it contained a few − supercoils Fig. 2 A, lane 8. Incubation of pRLM375 DNA with DNA gyrase alone for 10 min introduced about 5 or 6 additional − supercoils Fig. 2 A, lane 7.