[Dependence of properties of polyclonal antibodies to (2'-5')-oligoadenylates on the method of hapten binding to an immunogen]. / Zavisimost' svoistv poliklonal'nykh antitel k (2'-5') oligoadenilatam ot sposoba prisoedineniia gaptena k immunogenu.

To elucidate the antibody-(2'-5')oligoadenylate relation to the mode of the hapten-immunogen conjugation, a new (2'-5')oligoadenylic acid trimer derivative containing a 2'-terminal N6-(5-carboxypentyl)adenosine and its 125I-labeled immunogenic conjugate were synthesized. The immunization with this conjugate and with a conjugate based on the 2',3'-O-[1-(2-carboxyethyl)]ethylidene derivative of the (2'-5')triadenylic acid gave antisera with different affinities toward modified (2'-5')oligonucleotides. Epitopes involved in the (2'-5')oligomer-binding to different antisera were found.

[Synthesis of 2',3',-dideoxy-3'-fluoradenosine and -guanosine, their 5'-triphosphates and a study of 2',3'-dideoxy-3'-fluoronucleoside- 5'-triphosphates as substrates for DNA-polymerases]. / Sintez 2',3'-didezoksi-3'-ftoradenozina i -guanozina, ikh 5'- trifosfatov i izuchenie 2',3'-didezoksi-3'-ftornukleozid-5'-trifosfato v kachestve substratov DNK-polimeraz.

Potential antiviral and antitumour nucleosides, 3'-fluoro-2', 3'-dideoxy-adenosine and -guanosine, have been synthesized by the chemical transglycosylation reaction using 5'-O-acetyl-3'-fluoro-2', 3'-dideoxy-thymidine and -uridine as donors of the carbohydrate fragment and persilylated 6-N-benzoyladenine and 2-N-palmitoylguanine as acceptors, respectively. 5'-Triphosphates of 3'-fluoro-2', 3'-dideoxy-thymidine, -cytidine, -adenosine, and -guanosine (dNTP(3'F] were synthesized and tested as terminators in cell-free system of DNA synthesis catalyzed by RNA-directed DNA polymerase (reverse transcriptase, RT) from the avian myeloblastosis virus (AMV) and E. coli DNA polymerase I (Klenow fragment). A method of estimating relative effectiveness of dNTP(3'F) incorporation into DNA growing chain in comparison with the natural substrates was developed. It is shown that, in case of AMV-RT, dATP(3'F), dCTP(3'F) incorporate 14 times less efficiently than dATP and dCTP respectively, and dTTP(3'F) 3 times less effectively than the corresponding natural substrates, whereas dGTP (3'F) is as efficient as dGTP. With E. coli DNA polymerase I (Klenow fragment) dATP (3'F) and dCTP(3'F) are ca. 100 times less efficient, and dTTP(3'F) and dGTP(3'F) are ca. 50 times less efficient than the respective natural substrates.

[Preparative synthesis of the antiviral nucleoside 9-beta-D-arabinofuranosyladenine by using bacterial cells]. / Preparativnyi sintez protivovirusnogo nukleozida 9-beta-D-arabinofuranoziladenina s pomoshch'iu bakterial'nykh kletok.

The conditions of synthesis of 9-beta-D-arabinofuranosyladenine, an antiviral nucleoside by intact cells of Escherichia coli capable of adenine transarabinosylation were studied. The cells were grown in meat-peptone broth supplemented with yeast extract. Cytosine arabinoside served as a donor of the arabinose residues. The pH value, temperature of the reaction medium and concentration of phosphate ions in it were shown to be significant factors defining the cell activity. Under optimal reaction conditions: 0.03 M potassium phosphate buffer, pH 6.75; 0.03 M cytosine arabinoside; 0.01 M adenine; 5 per cent of the cells; incubation time 12 hours; incubation temperature 60 degrees C the efficiency of 9-beta-D-arabinofuranosyladenine synthesis reached 90-95 mol % with respect to the initial adenine level.

[Adenosine transformation into adenosine-5'-monophosphate by intact Erwinia herbicola cells]. / Transformatsiia adenozina v adenozin-5'-monofosfat intaktnymi kletkami Erwinia herbicola.

Strain 47/3 was isolated from the natural sources of Erwinia herbicola. The cells of this strain contain nucleoside phosphate transferase responsible for specific phosphorylation of the adenosine 5'-hydroxyl group. With the use of the strain intact cells, conditions for preparation of AMP were determined. The cells were grown in the meat-peptone broth supplemented with yeast extract. p-Nitrophenylphosphate was used as a donor of phosphate groups. It was shown that the concentration of the reaction substrates, their ratio and PH of the reaction mixture were factors defining the cell activity. Under the optimal conditions (0.2 M acetate buffer, pH 4.5; concentrations of p-nitrophenylphosphate and adenosine 96 and 12 mg/ml respectively; concentration of the cells 1 per cent) the cells phosphorylated adenosine with a yield of 74 mol %. This indicates that the method may be used for production of AMP in preparative amounts.