[Epoxy ring scission in the oleandomycin molecule during aging]. / O raskrytii époksidnogo kol'tsa v molekule oleandomitsina v protsesse stareniia.

Opening of the epoxide ring in the molecule of oleandomycin phosphate in the process of its aging was shown to be possible by the data of the analysis. Certain correlation between the "glycol" content and drug activity was detected.

[Oxidative destruction of the heptaene antibiotic levorin]. / Izuchenie okislitel'noi destruktsii geptaenovogo antibiotika levorina.

Levorin destruction in oxygen, argon or air at various temperature levels was studied. It was found that destruction of the antibiotic molecule was mainly due to its interaction with oxygen. As a result the heptaenic chromophore was oxidized and triene and tetraene formed. Oxidation of levorin was accompanied by splitting out of paraaminoacetophenone. Destruction of levorin in the absence of oxygen was retarded.

[Polyene antibiotics stability, study of the rate of the heterogeneous destruction of the hepataene antibiotic levorin by an "accelerated aging" method and the possibility of predicting the shelf life of levorin]. / Stabil'nost' polienovykh antibiotikov, izuchenie skorosti geterogennoi destrucktsii gepatenovogo antibiotika levorina metodom "uskorennogo stareniia" i vozmozhnost' prognozirovaniia sroka khraneniia levorina.

The data on stability of levorin of various purity levels stored under natural conditions and under conditions of thermic rapid inactivation are presented. When the ratio of oxygen to the antibiotic was 1 mole/1 mole the kinetic inactivation curve was of a multistage character with periods of active destruction and quasistatic state. The use of thermic inactivation as a method of accelerated aging is substantiated. A procedure for calculation of the expiry date of the antibiotic is described.

[Formation by the mycoheptin producer of aureothin and pentaene 2814-P, separated into its mycopentene-1 and mycopentene-2 components]. / Obrazovanie produtsentom mikogeptina aureotina i pentaena 2814-P, razdelennogo na komponenty mikopenten-1 i mikopenten-2.

Aureothin, a toxic substance of non-polyenic nature and pentaen 2814-P were isolated from the metabolites of Streptoverticillium mycoheptinicum, the organism producing mycoheptaine. The above substances are also produced by other actinomycetes. The pentaenic antibiotic was divided into 2 components. Physico-chemical and biological properties, as well as the composition of the substances were studied.

[Formation of peroxide compounds and their role in the inactivation of polyene antibiotics levorin and mycoheptin]. / Obrazovanie perekisnykh soedinenii i ikh rol' v inaktivatsii polienovykh antibiotikov levorina i mikogeptina.

The kinetics of peroxide formation in the process of levorin and mycoheptin oxidation at a temperature of 57 degrees C was studied. It was shown that the peroxide compounds actively participated in the processes of levorin and mycoheptin inactivation as intermediate products of their transformation. Addition of the peroxides increased the rate of the antibiotic degradation even if there was no oxygen and subsequently decreased the periods of their storage. Conditions for the use of the iodometric method for determination of the peroxides in the poyenic compounds are discussed.

[Study of the dynamics of hepataene and pentaene formation by a culture of Streptoverticillium mucoheptinicum strain 44B/1 in the process of biosynthesis]. / Izuchenie dinamiki obrazovaniia geptaena i pentaenov kul'turoi Streptoverticillium mucoheptinicum shtamn 44B/1 v protsesse biosinteza.

In the process of growth Streptoverticillium mycoheptinicum, strain 44B/I produced simultaneously a two-component pentaenic antibiotic (mycopenten) and a heptaenic antibiotic (mycoheptin) by the 1st day of cultivation. The ratio of the components remained constant during the whole fermentation process. When grown on the medium with sodium thiosulfate (under conditions of the changed medium potential) the culture produced the heptaen and a mixture of the components with the background absorption of the UV spectrum at 290--360 nm. The ratio of the heptaen and the mixture was also constant during the whole fermentation process.

[Streptoverticillium albireticuli var. kokandum, a producer of the new antifungal pentaene antibiotic, kokandomycin]. / Streptoverticillium albireticuli var. kokandum--produtsent novogo protivorgribkovogo pentaenovogo antibiotika kokandomitsina

Morphological, cultural and physiological properties of actinomycete L10-0208 were studied. It was shown that actinomycete was a new natural variant. It was named Streptoverticillium alboreticuli var. kokandum. The physico-chemical characteristics of the pentaenic antibiotic are presented and its originality is shown. The antibiotic is named kokandomycin.