[Spatial Models of Piezo Proteins and Protein-Protein Interaction Networks in Trichoplax Animals (Placozoa)].

The marine free-living organism Trichoplax (phylum Placozoa) resembles a unicellular amoeba in shape and type of movement. Trichoplax diverged from the main evolutionary tree in the Neoproterozoic Era. Trichoplax provides one of the simplest models of multicellular animals and a strong example of how cells of an organism interact to form an ensemble during its development and movement. Two orthologs of the mouse Piezo1 protein (6B3R) were found in two Trichoplax haplotypes, H1 and H2, as a result of a search for similar sequences in the NCBI databases. Spatial models of the respective proteins XP_002112008.1 and RDD46920.1 were created via a structural alignment with 6KG7 (mouse Piezo2) template. Their domain structures were analyzed, and a limited graph of protein-protein interactions was constructed for the hypothetical mechanosensor XP_002112008.1. The possibility of signal transduction from the mechanoreceptor to membrane complexes, the cytoplasm, and the cell nucleus was shown. Trichoplax mechanoreceptors were assumed to play a role in perception of force stimuli from neighbor cells and the environment. Based on the results, the primitive Trichoplax organism was proposed as the simplest multicellular model of mechanical and morphogenetic movements.

[Spatial Reconstruction of TRPC Mechanoreceptors of the Ctenophore Mnemiopsis leidyi A. Agassiz, 1865].

The ctenophore Mnemiopsis leidyi A. Agassiz, 1865 responds to gentle mechanical stimulus with intense luminescence; however, the mechanism of this phenomenon is unknown. We searched for possible mechanosensitive receptors that initiate signal transduction resulting in photoprotein luminescence. The three orthologous genes of mouse (5z96) and drosophila (5vkq) TRPC-proteins, such as ML234550a-PA (860 a.a.), ML03701a-PA (828 a.a.), and ML038011a-PA (1395 a.a.), were found in the M. leidyi genome. The latter protein contains a long ankyrin helix consisting of 16 ANK domains. Study of the annotated domains and the network of interactions between the interactome proteins suggests that the ML234550a-PA and ML03701a-PA proteins carry out cytoplasmic transduction, but ML038011a-PA provides intranuclear transduction of mechanical signals. Spatial reconstruction of the studied proteins revealed differences in their structure, which may be related to various functions of these proteins in the cell. The question of which of these proteins is involved in the initiation of luminescence after mechanical stimulation is discussed.

Protective Properties of Lanthanum Nitrate against Pathogens with Various Morphological and Functional Properties.

Dose-dependent protective effects of lanthanum nitrate solution and gel were shown on the model of experimental infection caused by a virulent strain of Shigella flexneri 2a or opportunistic bacteria Klebsiella pneumoniae in outbred and DBA mice.