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Biomedical subjects

F E Hahn

Publications and source records attributed to F E Hahn.

At least 55 records · Page 3Linked to original sources
PubMed1969

Berberine: complex with DNA.

A complex of calf-thymus DNA with berberine sediments in the analytical ultracentrifuge. The DNA produced systematic changes in the absorption spectrum of berberine which suggest that single alkaloid molecules bind to DNA. Flow dichroism of purines and pyrimidines and of berberine in the complex with DNA had the same signs and magnitudes. Berberine shifted the thermal strand separation profile of DNA to higher temperatures. Therefore, the alkaloid forms a complex with DNA, probably by intercalation.

Animals↗
PubMed1967

Quinacrine (atebrin): mode of action.

Quinacrine at a concentration of 8 x 10(-4) mole per liter is bactericidal for Escherichia coli, blocks DNA synthesis, and inhibits the syntheses of RNA and protein strongly. At a concentration of 2x 10(-4) mole per liter, the drug is bacteriostatic, the syntheses of protein and DNA (but not that of RNA) are partially inhibited, and the bacteria grow into giant filaments. Impairment of DNA replication is proposed as the mode of action of quinacrine.

DNA, Bacterial↗
PubMed1966

Chloroquine: physiological basis of drug resistance in Plasmodium berghei.

Mouse erythrocytes, parasitized by chloroquine-sensitive plasmodia, concentrate this drug in vivo to levels over twice as high as erythrocytes parasitized by chloroquine-resistant plasmodia; nonparasitized red cells accumulate little chloroquine. Selective toxicity of this drug may depend upon a special drug-concentrating mechanism of plasmodic impairment of such mechanism.

Animals↗
PubMed1966

Chloroquine: mode of action.

The drug chloroquine is bactericidal for Bacillus megaterium; it inhibits DNA and RNA biosynthesis and produces rapid degradation of ribosomes and dissimilation of ribosomal RNA. Inhibition of protein synthesis is also observed, evidently as a secondary effect. Inhibition of DNA replication is proposed as a general mechanism of the antimicrobial action of chloroquine.

Bacillus megaterium↗
PubMed1965

DNA: reaction with chloroquine.

Diflerence spectrophotometry shows that double-stranded DNA produces mnarked changes in the absorption spectrum of chloroquine; only minor changes occur with single-stranded DNA. A DNA-chloroquine complex was demonstrated to sediment in the analytical ultracentrifuge. Chloroquine strongly elevated the thermal dissociation temperature, T(m), of DNA. It is concluded that the drug forms a complex with DNA by ionic interaction and stabilizes the helix.

Chemical Phenomena↗