Antibacterial effect of chitosan on the morphofunctional organization of clinical strains of Klebsiella pneumoniae and Staphylococcus aureus was studied by transmission electron microscopy. Chitosan promoted aggregation of bacterial cells and disorganization of bacterial cell wall and cytoplasmic membrane, which leads to the release of bacterial contents into the environment. These structural changes result in bacterial death.

The genus Saccobasis is revised based on an integrative approach. The name S. polymorpha is synonymized with S. polita because neither molecular nor significant morphological differences were found between these taxa. At the same time, a group of Saccobasis specimens is proposed to be considered a new variety S. polita var. arctica as it forms a separate clade in constructed trees and differs morphologically from previously recognized taxa. Detailed descriptions of the species S. polita and its new variety are provided. The differences between Saccobasis and morphologically similar taxa, as well as the variability of the main features of the genus are considered. The characteristic features of S. polita var. polita and S. polita var. arctica are illustrated with photomicrographs, and the distribution of both taxa is pointed on a map. РезюмеПроведена ревизия рода Saccobasis на основе интегративного подхода. Название S. polymorpha синонимизировано с S. polita поскольку не обнаружено ни молекулярных, ни существенных морфологических отличий между этими таксонами. При этом группу образцов, образующих отдельную кладу на построенных филогенетических древах и отличающихся рядом морфологических признаков, экологией и распространением, предложено рассматривать как отдельную разновидность S. polita var. arctica. Приводится подробное описание вида и новой разновидности, рассматриваются их отличия от морфологически сходных видов. Работа иллюстрирована фотографиями признаков S. polita var. polita и S. polita var. arctica, а также картой их точечного распространения.

An original procedure which permits to isolate circulating immune complexes (CIC) from the blood plasma in a form of a dense pellet was developed. This procedure was applied for the ultrastructural analysis of CIC isolated from blood of healthy blood donors and patients suffering from Yersinia enterocolitica (YE) and Yersinia pseudotuberculosis (YP) infections. The here reported method of CIC isolation from blood plasma permitted to visualize CIC electronmicroscopically as amorphous masses of low, middle, and high electron density with inclusions of cell debris. In contrast to CIC of healthy blood donors, CIC of infected patients contained various bacteria and fungiformic structures. For the first time, this method made possible an ultrastructural demonstration of bacterial destruction outside of phagocytes in vivo. This method also permits to visualize and identify bacteria in cases of lingering forms of infection when hemoculture tests fail. Therefore, electronmicroscopic examination of CIC preparations from the blood plasma might be a very informative indicator of bacteriemia in the course of an infection process and serve as an indicator of therapeutic effects. In lingering forms of an infection process, ultrastructural analysis of CIC preparations can be of prognostic value and serve as an indicator of therapeutic effects. This method might be also advantageous as an additional test for the exposure of latent bacterial persistence in diagnostically complicated cases.

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