Цель работы. Анализ возможности длительного сохранения штаммов Y. pestis в ассоциации с амебами Acanthamoeba sp. Материалы и методы. Исследовано взаимодействие амеб Acanthamoeba sp., выделенных из почв нор грызунов в Прикаспийском песчаном, Волго-Уральском степном и Прикаспийском Северо-Западном степном природных очагах чумы, с 4 штаммами Y. pestis основного подвида, 1 штаммом кавказского и 1 штаммом алтайского подвида. Результаты и обсуждение. Установлено, что штаммы основного подвида сохраняются в клетках амеб при температуре 26 °С и влажности 20 % (моделирование засушливых периодов в природных очагах чумы) в течение двух-четырех месяцев проведения эксперимента и в 10-20 раз дольше, чем в чистой культуре. Два штамма неосновных подвидов не показали увеличения длительности выживания в ассоциации с акантамебами, что может быть связано с их пониженной резистентностью к фагоцитозу амебами этого рода. Методами флуоресцентной и электронной трансмиссионной микроскопии установлено, что клетки возбудителя чумы сохраняются в клетках амеб в индивидуальных вакуолях, окруженных эндоплазматическим ретикулумом. Полученные данные могут свидетельствовать о возможном участии амеб Acanthamoeba sp. в сохранении Y. pestis в почвенных биоценозах природных очагов чумы.
In non-pigmented and plasmid-deprived mutants-isogenic variants of highly virulent Yersinia pestis 231 strain-studied is the mechanism of biofilm formation on biotic surfaces, both in vitro (on the laboratory model of nematode Caenorhabdiitis elegans) and in vivo (inside the alimentary tract of Nosopsyllus laeviceps flea). It is determined that spontaneous loss of ability to form biofilms and generate pigmented colonies in the mutants is probably caused not only by the deletion of the whole chromosome pigmentation fragment, but also by a point(single base) mutation in structural hms operon. It is demonstrated that the absence of pCad, pFra or pPst plasmids does not have an impact on the ability of plasmid-deprived mutants to form biofilm on the cuticle of nematode C. elegans.
This paper investigates storage stability (165-day period) of whole oat flour obtained by hydrothermal treatment and stored at 40 degrees Celsius in cloth bags and flour mixture containing 66.7 percent of whole oat flour obtained by hydrothermal treatment, 13.3 percent of fenugreek seed powder, 6 percent of dry gluten, and 14 percent of wheat flour stored at 20 and 40 degrees Celsius in various types of bags (namely, cloth and plastic). Measurement of moisture content, acidity, acidity of flour by water-alcohol extraction, an acid number of fat as well as microbiological load was carried out during the storage period. The results revealed that at all storage conditions with the increase of storage time flour acidity, acidity of flour by wateralcohol extraction, and an acid number of fat increased, whereas microbiological load decreased. Changes in moisture content of stored samples are affected by various temperatures and in different types of bags. However, flour mixture stored at 20 degrees Celsius remained shelf stable over the time storage period. Whole oat flour stored at 40 degrees Celsius in cloth bags showed larger increase in the acidity, acidity of flour by wateralcohol extraction, and an acid number of fat. Flour mixture containing fenugreek seed powder and stored in plastic bags saw lower increase in acidity and an acid number of fat than the flour mixture in cloth bags and whole oat flour at 40 degrees Celsius.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.