[A simple enzymatic method for the quantitative determination of cordycepin and [3'-deoxy]ATP in rat brain tissue]. / Prostoi énzimaticheskii metod kolichestvennogo opredeleniia korditsepina i [3'-dezoksi] ATF v tkani golovnogo mozga krys.

A procedure for quantitative estimation of cordycepin (3'-deoxyadenosine), a specific inhibitor of post-transcriptional polyadenylation of pre-mRNA and of a metabolite of cordycepin 3'-deoxyATP in rat brain tissue is described. The procedure is based on evaluation of an inhibitory effect on the synthesis of polyA in vitro of total nucleoside and nucleoside and nucleoside triphosphate preparations isolated from the animal brain after cordycepin administration. Homogenates of intact animal brain were used as a source of "crude" polyA polymerase preparations.

The effect of poly(A) segment size on the inhibition of hnRNA biosynthesis by cordycepin in rat brain cells.

In rat brain cells low doses of cordycepin (3'-deoxyadenosine) practically do not inhibit biosynthesis of hnRNA with short 3'-terminal poly(A) segments. The same antibiotic doses are sufficient for effective inhibition of biosynthesis of hnRNA containing long poly(A) chains.

[Chromatographic method for quantitative determination of cordycepin in rat brain tissue after intraperitoneal injection of the antibiotic]. / Khromatograficheskii metod kolichestvennogo opredeleniia korditsepina v tkani mozga krys posle vnutribriushinnoi in"ektsii antibiotika.

A procedure is developed for quantitative estimation of intraperitoneally administered unlabelled cordycepin in acid soluble pool isolated from rat brain tissue. The fraction containing 2'- and 3'-deoxyriboadenosine (cordycepin) in acid soluble pool of rat brain was isolated after consecutive chromatography on columns of Dowex 1 X 8, Dihydroxyboryl-SP 500 and Sephasorb-HP. At the same time, 2'-deoxyriboadenosine was isolated from the acid soluble pool fraction of control animals. Content of the antibiotic in brain tissue was estimated by its difference in these two fractions (control/experiment).

A three-stage chromatographic procedure for cordycepin. Quantitative estimation in rat brain tissue.

A technique for the quantitative estimation of intraperitoneally injected unlabelled cordycepin in the acid soluble pool (ASP) isolated from rat brain tissue has been suggested. It consists of consecutive chromatography of ASP on columns of Dowex 1 X 8, Dihydroxyboryl-SP500 and Sephasorb-HP. As a result, the fraction containing 2'-deoxyriboadenosine and 3'-deoxyriboadenosine (cordycepin) was isolated from the brain tissue ASP of experimental animals which were given a cordycepin injection. The 2'-deoxyriboadenosine fraction was isolated from tissue ASP of control animals which were not given an injection of this antibiotic. Brain tissue antibiotic content was estimated by the difference in mumolar nucleosides quantity values in the two fractions (control/experiment).

[Dependence of cordycepin inhibition of heterogeneous nuclear RNA biosynthesis in rat brain on the size of the poly(A) segments]. / Zavisimost' ingibirovaniia biosinteza geterogennoi iadernoi RNK mozga krys korditsepinom ot razmerov segmentov poli(A).

A study was made of the effect of cordicepin on the biosynthesis of rat brain heterogeneous nuclear RNA (hnRNA) fractions, such as poly(A-)hnRNA, oligo(A+)hnRNA and poly(A+)hnRNA differing in the size of poly(A)-segments. Cordicepin was shown to inhibit the biosynthesis of poly(A+)hnRNA alone. However, small doses of the antibiotic do not virtually inhibit the biosynthesis of hnRNA with shorter segments of poly(A). At the same time they inhibit the biosynthesis of hnRNA containing long chains of poly(A) in the 3'-end. A possible molecular mechanism of the phenomenon reviewed is under discussion.

Quantitative estimate of unlabelled cordycepin in acid-soluble pool isolated from rat brain tissue after intraperitoneal injection of the inhibitor.

A technique for the quantitative estimation of intraperitoneally injected unlabelled cordycepin in an acid-soluble pool (ASP) isolated from rat brain tissue is suggested. It consists in consecutive chromatography of ASP on Dowex 1 X 8, Dihydroxyboryl = SP500 and Sephasorb-HP. The fraction containing 2'-deoxyriboadenosine and 3'-deoxyriboadenosine (cordycepin) has been isolated from brain tissue ASP of experimental animals after a cordycepin injection. 2'-Deoxyriboadenosine fraction has been isolated from tissue ASP of the control animals not subjected to an inhibitor injection. Brain tissue antibiotic content has been estimated by the difference in nucleoside quantity values (microM) in these two fractions (control/experiment).