[Various mechanisms of the depriming effect of bacterial endotoxin on drug metabolism]. / Nekotorye mekhanizmy deprimiruiushchego vliianiia bakterial'nogo éndotoksina na metabolizm lekarstvennykh veshchestv.

The effect of an endotoxin from Sh. Boydii on the biotransformation of amidopyrine and acetanilide, the activity of microsomal monooxygenases, hemoxygenase, and xanthine oxidase, the lipid peroxidation (LPO) intensity, the phospholipid spectrum, and the solubilization of microsomal membrane components was studied by intraperitoneal injections (2.5 mg/kg) in rats. It was found that the endotoxin inhibits the reactions of C- and N-acetanilide hydroxylation, N-amidopyrine demethylation, acetanilide hydrolysis at the amide bond, conjugation of aminophenol metabolites with glucuronic acid and sulfate, and 4-aminoantipyrine binding to acetate. The endotoxin effect reached maximum 24 h after injection and was observed for 96 h. The inhibition of metabolism of the test preparations is related to a decrease in the content of cytochrome P-450 and in the activity of 1A2, its 2B, 2C, 3A, and 2E1 isoforms. This is obviously caused by activated LPO and enhanced nitric oxide synthesis, as evidenced by a tenfold increase in the content of NO metabolites (nitrites and nitrates) in the blood of test animals. In clinical practice, it is necessary to take into account the possibility of a significant biotransformation of drugs in the acute period of bacterial infection, which may lead to changes in the pharmacological effect and toxicity of some drugs.

[Composition of the folded chromosome from Anabaena variabilis]. / Sostav kompaktnoi khromosomy Anabaena variabilis.

A "heavy" nucleoid (folded chromosome) from A. variabilis has been isolated in preparative amounts. The composition of the folded chromosome and that of a more simple DNA--protein complex isolated from the "heavy" nucleoid of A. variabilis by chromatography on a column with methylated albumin (MAK) were studied. It was shown that the "heavy" nucleoids contain total cell DNA in a complex with the definite membrane fragment, which can be discovered by a large number of membrane proteins, phospholipids, lipopolysaccharides and amino sugars. After MAK chromatography the DNA--protein complex also contains total cellular DNA, a negligible amount of membrane polypeptides and noticeable amounts of phospholipids and lipopolysaccharides.

[Some physico-chemical properties of the compact chromosome of Ananbaena variabilis]. / Nekotorye fiziko-khimicheskie kharakteristiki kompaktnoi khromosomy Anabaena variabilis.

It was shown that total DNA of the blue-green algae A. variabilis can be isolated as a compact particle with the sedimentation constant of 2700--2900S by lysis of the cells with the TritonX-100--sodium deoxycholate mixture in 1.0 M NaCl. The structure isolated is sensitive to ribonuclease and the hydrodynamic shift. It was found that within a compact chromosome A. variabilis DNA is circular and negatively superhelicized. The density of superturns of the DNA in 0,2 M NaCl at 20 degrees C is 0,061, which corresponds to one negative turn per 165 pairs of DNA bases.