[Localization of the structural gene for botulinum neurotoxin type A using synthetic DNA probe for neurotoxin light chain]. / Poisk lokalizatsii strukturnogo gena botulinicheskogo neirotoksina tipa A s ispol'zovaniem sinteticheskogo DNK-zonda k legkoi tsepi neirotoksina.

To obtain the information on the genetic control of toxin production in the botulism causative agents, the oligonucleotides were synthesized as the molecular probes by translation of the amino acid sequence of the botulinic type A neurotoxin. The optimal conditions for hybridization of botulinic DNA with the synthetic DNA probes were determined and the probes specificity was demonstrated. The DNA fragments homologous to the probes used were shown to belong to bacterial genome, but not to bacteriophage one.

[Morphological and histochemical reactions of an organism to the administration of Clostridium botulinum toxin. IX. Reactions of the neurons of the abducens nerve nucleus and of the Darkshevich's nucleus to the administration of C. botulinum type B toxin]. / Morfologicheskaia i gistokhimicheskaia kharakteristika reaktsii organizma na vvedenie toksina Clostridium botulinum. Soobshchenie IX. Reaktsiia neironov iadra otvodiashchego nerva i iadra Darkshevicha na vvedenie toksina C. botulinum tipa B.

Pathomorphological and histochemical study carried out in guinea pigs at the stage of paralysis of the limbs after the oral administration of C. botulinum toxin has revealed the presence of morpho-metabolic changes pertaining to phase 2 of the development of dystrophic processes in the neurons of the nucleus of the abducent nerve and Darkshevich's nucleus. At the myasthenic stage the development of dystrophic processes in the neurons of Darkshevich's nucleus has been found to reach phase 3. The study indicates that C. botulinum toxin possesses different tropism in respect of the neurons of the oculomotor nuclei; this fact correlates with the clinical picture of botulism.

[Morphological and histochemical characteristics of the organism's reaction to administration of Cl botulinum toxin. IV. Cytochemical changes in the cells of the mesencephalic nucleus of trigeminal nerve following administration of Cl. botulinum type B toxin]. / Morfologicheskaiai gistokhimicheskaia kharakteristika reaktsii organizma na vvedenie tosina Cl. botulinum. Soobshchenie IV. Tsitokhimicheskie izmenenia v kletkakh mezentsefalicheskogo iadra troinichnogo nerva posle vvedeniia toksina Cl. botulinum tipa B

After the administration to guinea pigs per os of 1 Dlm of botulin toxin, type B, a change of the RNA synthesis in the nucleoli and DNA depolymerization in the nuclei was observed in some of the cells of the mesencephalic nucleus of the trigeminal nerve. An increase in the activity of succinic dehydrogenase and of acid phosphatase coursed without any necrotic processes in the cells. Basing upon the changes in the activity of succinic dehydrogenase in the neurons of the mesencephalic nucleus a conclusion was drawn that hypoxia began to develop at the period of appearance of paralyses of the limbs and reached its maximum in myasthenia.

[Morphological and histochemical characteristics of the reaction of the body to Cl. botulinum toxin administration. III. The cellular reaction of the diaphragmatic nerve nucleus to the administration of Cl. botulinum type B toxin]. / Morfologicheskaia i gistokhimicheskaia kharakteristika reaktsii organizma na vvedenie toksina C. botulinum. Soobshchenie III. Reaktsiia kletok iadra diafragmal'nogo nerva na vvedenie toksina Cl. botulinum tipa B

On the appearance in the animals (guinea pigs) of paralysis of the limbs and myasthenia after the administration of Cl. botulinum, type B, toxin, there was seen a considerable vascular hyperemia of the spinal cord, and in the neurons of the phrenic nerve nucleus there developed dystrophic-necrotic processes coursing with a marked swelling, hyperchromasia and tigrolysis. As revealed histochemically, at this stage of the botulin intoxication the neurons of the phrenic nerve nucleus displayed metabolic changes expressed in the altered activity of succinic dehydrogenase, acid phosphatase and cholinesterase.

[Contamination of fish by agents of botulism type F and differentiating it from type E]. / Obsemennost' ryby vozbuditeliami botulizma tipa F i differentsiatsiia ego s tipom E

A total of 1859 samples of fish and various sea animals were examined for contamination with causative agent of botulism. The cultural fluid of 4--5-day cultures of the samples was tested in the reaction of neutralization with the diagnostic antitoxic antibotulin sera. types A, B, C, E. The causative agents of botulism (types A--7,B--16, C--5, E--128) were revealed in 156 samples. The sera were diluted to the concentration of 1 IU/ml for differentiation of the toxins types B and F in the neutralization test. Of 128 samples which gave a positive reaction with the serum of type E, 75 were identified as type F. In connection with the aforesaid the authors recommended in all the cases of botulism of type E in man to carry out differential diagnosis between the causative agents of botulism of types E and F and, on the basis of these data, to solve the problem on the necessity of production of therapeutic antibotulin serum of type F.

[Isolation and properties of a highly purified Clostridium botulinum type F toxin]. / Vydelenie i svoistva vysokochishchennogo toksina Clostridium botulinum tipa F.

A scheme for isolation of highly purified type F Cl. botulinum toxin has been developed. The scheme allows one to obtain the toxin with specific activity of 1.5--4.0 X 10(7) Dlm/mg protein, molecular weight of 150,000 daltons, a typical protein UV spectrum and the optical density ratio E280/E260 = 1.98.

[The use of the polymerase chain reaction for the identification of Clostridium botulinum type A strains]. / Ispol'zovanie polimeraznoi tsepnoi reaktsii dlia identifikatsii shtammov Clostridium botulinum tipa A.

Polymerase chain reaction (PCR) for the identification of C.botulinum of type A was developed. As primers, oligonucleotides corresponding to sequences 913 -- 932 and 1852 -- 1871 of the gene of type A botulinic neurotoxin were used. The study revealed that under optimum conditions the positive result of the reaction was registered only when the DNA of C.botulinum strains of type A (11 strains) was used, but not that of C.botulinum strains of other types (11 strains of type B, 5 strains of type C, 2 strains of type D, 6 strains of type E and 1 strain of type G). High sensitivity, specificity and rapidity of PCR open good prospects for its practical use.

[Detection of atoxigenic variants in Cl. botulinum type A and B cultures exposed to different treatments]. / Vyiavlenie atoksigennykh variantov v kul'turakh Cl botulinum tipov A i B pod vliianiem razlichnykh vozdeîstviî

A possibility of detection of atoxigenic clones in the cultures of Cl. botulinum, types A and B, under conditions of treatment with acridine strains, UV-irradiation and heating of spores was studied. Of the 10 strains investigated, atoxigenic variants were obtained only in 3, belonging to type B; the frequency of formation of atoxigenic clones under the effect of ethidium bronide constituted 36--45.7%, and of the UV-irradiation-4.2%; heating of spores proved to be ineffective. A frequent loss of the toxigenicity sign coincided with the view on the elimination of the episomal determinant of the toxin-formation, not with the mutational nature-of this change. An association between the differences in stability of retention of the toxigenicity signs in various strains and types of Cl. botulinum and possible differences of the corresponding genetic determinants of the toxin formation is discussed.

[Bacteriophage induction in cultures of C1. botulinum type A]. / Induktsiia bakteriofaga v kul'turakh C1. botulinum tipa A.

The authors describe the mitomycin induction of bacteriophages in strains No. 4/2, 98, and 345 of Cl. botulinum, type A. All the strains under study produced phages of the same morphology with a head and a process capable of contraction. The phages detected by electron microscopy failed to express any lytic activity on the strains of type A and other Cl. botulinum types neither in the fluid nor in the hard nutrient media. The data obtained supplemented and widened the view on the incidence of phage carrier state in the cultures of botulism causative agent.

[Characteristics of the activation of type E. Cl. botulinum toxins]. / Nekotorye osobennosti aktivatsii botulinicheskogo toksina tipa E.

Molecular changes occurring in type E. Cl. botulinum single-chain toxin as the result of treatment with trypsin under different conditions were studied. The intensity of activation of the precursor and the ensuing changes of its molecular structure were found to depend on the pH of the medium. At pH 6.0 complete activation induced by the trypsin treatment of the single-chain toxin coincided with complete break-up of the polypeptide chain, while at pH 5.0 the toxin was completely activated before all its molecules could acquire the double-chain structure. At pH 4.5 no increase in the potency of the toxin was registered even in those cases when break-up of the molecules was as pronounced as by the moment of complete activation of the toxin at pH 5.0. These data suggest that activation is not direct consequence of break-up of the peptide bond responsible for the formation of a double-chain molecule. Trypsin-induced activation seems to be linked with the splitting of some peptide bond in one of the end areas of the molecule.