Providencia stuartii is the most common Providencia species capable of causing human infections. Currently P. stuartii is involved in high incidence of urinary tract infections in catheterized patients. The ability of bacteria to swarm on semisolid (viscous) surfaces and adhere to and invade host cells determines the specificity of the disease pathogenesis and its therapy. In the present study we demonstrated morphological changes of P. stuartii NK cells during migration on the viscous medium and discussed adhesive and invasive properties utilizing the HeLa-M cell line as a host model. To visualize the interaction of P. stuartii NK bacterial cells with eukaryotic cells in vitro scanning electron and confocal microscopy were performed. We found that bacteria P. stuartii NK are able to adhere to and invade HeLa-M epithelial cells and these properties depend on the age of bacterial culture. Also, to invade the host cells the infectious dose of the bacteria is essential. The microphotographs indicate that after incubation of bacterial P. stuartii NK cells together with epithelial cells the bacterial cells both were adhered onto and invaded into the host cells.

Two multienzyme bacterial preparations of α-amylase of Bacillus licheniformis and Amylosubtilin ® were used in order to modify potato starch at various enzyme concentrations. Eight types of starch were obtained, and their morphological, functional, and physical and chemical characteristics were studied. Induction of enzyme preparations allowed obtaining starches characterized by extended solubility and water-sorption ability and also lower gelation temperatures and viscosity. It was found that studied amylolytic preparations do have different effects on starch granules, despite the identical major amylase activities. e combination of the characteristics studied in the enzymatically modified starches makes them promising for the use as a component of food systems requiring the corrections of their textural features.

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