Morphological changes and luminescence of Escherichia coli in contact with Mn 2 O 3 and Co 3 O 4 ultrafine particles as components of a mineral feed additive

The spread of antibiotic resistance and mineral depletion in soils encourages an intensive search for highly effective and environmentally safe bactericidal agents and sources of macro- and micro-elements. The most profitable solution would combine both the described tasks. Ultrafine particles (UFPs) have this functionality. Thus, this study aimed to analyze the bioluminescence and external morphological changes of cells after contact with M O and Co O UFPs at effective concentrations (ECs). The antibiotic properties of the studied samples were determined on a multifunctional microplate analyzer TECAN Infinite F200 (Tecan Austria GmbH, Austria) by fixing the luminescence value of the bacterial strain (Ecolum, NVO Immunotech Closed Joint Stock Company, Russia). Morphological changes in the cell structure were evaluated using a Certus Standard EG-5000 atomic force microscope equipped with NSPEC software (Nano Scan Technology LLC, Russia). The obtained results indicate high bactericidal properties of Co O and Mn O UFPs (EC at 3.1 × 10 and 1.9 × 10 mol/L, respectively) due to the degradation of the cell wall, pathological increase in size, disruption of septic processes, and loss of cytoplasmic contents. The prospects for the environmentally safe use of ultrafine materials are outlined. The limits of the dosages of Co O and Mn O UFPs recommended for further study and in feeding farm animals are established (no more than 4.9 × 10 mol/L for Mn O UFPs and 1.5 × 10 mol/L for Co O UFPs). The limitation of the work is the lack of experiments to determine the mechanisms of the toxic effect of UFP on bacteria, protein structures, and DNA and oxidative stress, which is planned to be performed in the future together with and studies on animals.