[Influence of cultivation temperature and Yersinia pestis fra-operon carriage on morphological features of Yersinia pseudotuberculosis].

AIM: Studies of influence of Yersinia pestis fra-operon carriage on morphological properties of Y. pseudotuberculosis recipient strain cells and colonies at different temperature and cultivation time. MATERIALS AND METHODS: Cultures of Y. pseudotuberculosis isogenic variants were grown on solid nutrient medium at 4 - 6, 9 - 11, 26 - 28 and 36 - 38 degrees C. Indirect hemagglutination was used to determine F1 antigen production. Cytorefractometry was used to determine live cell percentage in colonies. Size and dividing cells percentage was evaluated by using phase-contrast microscope "Lyumam-I2". RESULTS: Time period between appearance of micro-colonies and achievement of maximum colony size increased with cultivation temperature decrease. Size of fra+ and fra- variant colony was not significantly different for every temperature regiment used and was significantly lower at the temperature of 36 - 38 degrees C. CONCLUSION: Temperature has a significant influence on population growth, colony size and form.

[Morphological structure of Yersinia pestis populations (strain EV) in the process of live plague vaccine production]. / Otsenka morfologicheskoi struktury populiatsii Yersinia pestis (shtamm EV) na étapakh prigotovleniia chumnoi zhivoi vaktsiny.

Morphological structure of the population of Yersinia pestis strain EV and the pattern of its changes during deep cultivation and in different stages of the live plague vaccine production was under study. The size range of cells most resistant to external influences was established.