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Cadmium is one of widespread toxic substances being hazardous for man as it capable to enter from the environment into animal and plant tissues and spreading along the food chain. We have studied the effect of Cd on the gills and hepatopancreas of the fresh water bivalve mollusks Anodontacygnea. After12-day acclimation the mollusks were kept for 24 and 72 hours in aquariums with Cd2+ concentrations of 10, 50 and 100 μg/L. Mass-spectrometric analysis has shown that Cd accumulation rate increased with increasing metal concentration in the water. At cadmium concentration of 100 μg/L the mollusk was capable of accumulating up to 0.44 μg of Cd per day. The accumulation of such high metal concentrations in the mollusk tissues did not kill the animals, but signs of oxidative stress, more pronounced in the gills than in the digestive gland, were observed. Exposure to cadmium ions decreased GSH concentration and increase Px activity in the mollusk gills as early as 24 hours after the beginning of the experiment. Changing the water in the aquarium had a considerable influence on SOD activity in the gills comparable with the effect of the addition of Cd. [ABSTRACT FROM AUTHOR]

Controlling the aggregation of vital bacterial proteins could be one of the new research directions and form the basis for the search and development of antibacterial drugs with targeted action. Such approach may be considered as an alternative one to antibiotics. Amyloidogenic regions can, like antibacterial peptides, interact with the "parent" protein, for example, ribosomal S1 protein (specific only for bacteria), and interfere with its functioning. The aim of the work was to search for peptides based on the ribosomal S1 protein from T. thermophilus, exhibiting both aggregation and antibacterial properties. The biological system of the response of Gram-negative bacteria T. thermophilus to the action of peptides was characterized. Among the seven studied peptides, designed based on the S1 protein sequence, the R23I (modified by the addition of HIV transcription factor fragment for bacterial cell penetration), R23T (modified), and V10I (unmodified) peptides have biological activity that inhibits the growth of T. thermophilus cells, that is, they have antimicrobial activity. But, only the R23I peptide had the most pronounced activity comparable with the commercial antibiotics. We have compared the proteome of peptide-treated and intact T. thermophilus cells. These important data indicate a decrease in the level of energy metabolism and anabolic processes, including the processes of biosynthesis of proteins and nucleic acids. Under the action of 20 and 50 μg/mL R23I, a decrease in the number of proteins in T. thermophilus cells was observed and S1 ribosomal protein was absent. The obtained results are important for understanding the mechanism of amyloidogenic peptides with antimicrobial activity and can be used to develop new and improved analogues. [ABSTRACT FROM AUTHOR]