Lichens, bryophytes and terrestrial algae of the Lake Untersee Oasis (Wohlthat Massiv, Dronning Maud Land, Antarctica)

Lake Untersee is the largest ice-covered freshwater lake in the interior of East Antarctica. The mountain oasis is situated around it in the Gruber Mts. of the Wohlthat Massif. For approximately 7,000 years the area has been free of ice and the local climate relatively stable. It is very severe, cold, and windy and dominated by intense evaporation and sublimation but with little melt. Relative humidity averages only 37%. Vegetation is sparse in the oasis and previously only poorly investigated. Two lichen species and no bryophytes were known from the area. In November-December 2018, a survey of terrestrial flora and vegetation was made. The list of lichens was completed for the area, bryophytes were found for the first time, and some terrestrial algae were collected. In total, 23 lichen species, 1 lichenicolous fungus, 1 moss, and 18 terrestrial algae were discovered for the locality. The abundance of each species within their habitats was also evaluated. The lichen flora of the Untersee Oasis is typical for continental oases and similar to other previously investigated internal territories of Dronning Maud Land, except for the very rich lichen flora of the Schirmacher Oasis

Control of animal products contamination with nitroimidazole group antibiotics

Antibiotic contamination of water and food is a particularly important environmental worldwide problem. Antibiotics are found in water, soil, and food, which negatively affects both the environment and the health of the entire world’s population. Therefore, it is important to control the content of antimicrobials. To solve this problem, scientists are developing new and improving existing methods for these preparation determination. The paper considers the possibility of applying the technique of high-performance liquid chromatography with mass spectrometric detection for the determination of nitroimidazole group antibiotics in meat raw materials. The method was evaluated in terms of the main characteristics taken into account during validation: accuracy, reproducibility, linearity, and specificity. Studies conducted on pork muscle tissue samples showed the absence of antibiotics of this group in all samples, which meets the requirements of regulatory documents

Assessing the Biological Safety of Dairy Products with Residual Antibiotics

Antibiotics have traditionally been used to prevent and treat common diseases in farm animals. However, residual antibiotics in dairy products and meat remain a serious public health problem, which is associated with antibiotic resistance. The research objective was to assess the impact of antibiotic contamination on the quality and safety of dairy products, the microbiological composition of milk, and antibiotic-resistant bacteria. The study featured six years of Russian and foreign scientific articles registered in PubMed (National Center for Biotechnology Information, USA), Scopus and ScienceDirect (Elsevier, the Netherlands), Web of Science (Clarivate, USA), and eLibrary.ru. The analysis involved 63 foreign and domestic sources. Residual antibiotics in milk inhibits the vital activity of lactic acid bacteria, which, in its turn, disrupts the technological process of yogurts, cheeses, etc. After such processing as normalization, pasteurization, and homogenization, antibiotics accumulate in fermented dairy products and bind with milk proteins and fats. Antibiotics, in their initial amount, enter yoghurts from dairy raw materials. In cheese production, antibiotics usually pass into the whey, but aminoglycosides, quinolones, and tetracyclines remain in the finished product because they bind with the protein fraction. The problem of biological safety of dairy products is associated with antibiotic resistance developed by human intestinal microbiota. This problem remains understudied, and the number of scientific papers on the matter is limited