Modulation of protein tyrosine phosphorylation in gastric mucosa during re-epithelization processes

AIM: To investigate the role of protein tyrosine phosphorylation in gastric wound formation and repair following ulceration.METHODS: Gastric lesions were induced in rats using restraint cold stress. To investigate the effect of oxidative and nitrosative cell stress on tyrosine phosphorylation during wound repair, total activity of protein tyrosine kinase (PTK), protein tyrosine phosphatase (PTP), antioxidant enzymes, nitric oxide synthase (NOS), 2’,5’-oligoadenylate synthetase, hydroxyl radical and zinc levels were assayed in parallel.RESULTS: Ulcer provocation induced an immediate decrease in tyrosine kinase (40% in plasma membranes and 56% in cytosol, P < 0.05) and phosphatase activity (threefold in plasma membranes and 3.3-fold in cytosol), followed by 2.3-2.4-fold decrease (P < 0.05) in protein phosphotyrosine content in the gastric mucosa. Ulceration induced no immediate change in superoxide dismutase (SOD) activity, 30% increase (P < 0.05) in catalase activity, 2.3-fold inhibition (P < 0.05) of glutathione peroxidase, 3.3-fold increase (P < 0.05) in hydroxyl radical content, and 2.3-fold decrease (P < 0.05) in zinc level in gastric mucosa. NOS activity was three times higher in gastric mucosa cells after cold stress. Following ulceration, PTK activity increased in plasma membranes and reached a maximum on day 4 after stress (twofold increase, P < 0.05), but remained inhibited (1.6-3-fold decrease on days 3, 4 and 5, P < 0.05) in the cytosol. Tyrosine phosphatases remained inhibited both in membranes and cytosol (1.5-2.4-fold, P < 0.05). NOS activity remained increased on days 1, 2 and 3 (3.8-, 2.6-, 2.2-fold, respectively, P < 0.05). Activity of SOD increased 1.6 times (P < 0.05) days 4 and 5 after stress. Catalase activity normalized after day 2. Glutathione peroxidase activity and zinc level decreased (3.3- and 2-fold, respectively, P < 0.05) on the last day. Activity of 2’,5’-oligoadenylate synthethase increased 2.8-fold (P < 0.05) at the beginning, and 1.6-2.3-fold (P < 0.05) during ulcer recuperation, and normalized on day 5, consistent with slowing of inflammation processes.CONCLUSION: These studies show diverse changes in total tyrosine kinase activity in gastric mucosa during the recovery process. Oxidative and nitrosative stress during lesion formation might lead to the observed reduction in tyrosine phosphorylation during ulceration.     

Role of Wnt/β-catenin signaling in embryonic cardiogenesis,postnatal formation and reconstruction of myocardium

Wnt/β-catenin signaling has a great and diverse influence on the formation, development, and vital activity of a great number of vertebrate tissues, including heart tissue. The role of Wnt/β-catenin signaling and β-catenin itself in the processes of cardiogenesis and adult myocardium functioning is not fully elucidated to date. The current review regards the attempt to generalize contemporary literature data on participation of this signaling pathway in embryogenesis and postnatal heart development, as well as in adult myocardium functioning in normal conditions and during stress adaptation, and aging, resulting in hypertrophy and heart remodeling. Based on the experimental articles and reviews, we can assume that Wnt/β-catenin signaling pathway is involved not only in controlling the cardiogenesis but also in processes of adaptation and remodeling of the adult organ. This control can be characterized as complicated and multistep and β-catenin appears to be a prospective candidate as a target for development of new approaches to adult myocardium pathologies therapy.     

Structural characterization of a new N‐substituted pantothenamide bound to pantothenate kinases from Klebsiella pneumoniae and Staphylococcus aureus

Pantothenate kinase (PanK) is the rate‐limiting enzyme in Coenzyme A biosynthesis, catalyzing the ATP‐dependent phosphorylation of pantothenate. We solved the co‐crystal structures of PanKs from Staphylococcus aureus (SaPanK) and Klebsiella pneumonia (KpPanK) with N‐[2‐(1,3‐benzodioxol‐5‐yl)ethyl] pantothenamide (N354‐Pan). Two different N354‐Pan conformers interact with polar/nonpolar mixed residues in SaPanK and aromatic residues in KpPanK. Additionally, phosphorylated N354‐Pan is found at the closed active site of SaPanK but not at the open active site of KpPanK, suggesting an exchange of the phosphorylated product with a new N354‐Pan only in KpPanK. Together, pantothenamides conformational flexibility and binding pocket are two key considerations for selective compound design. Proteins 2014; 82:1542–1548. © 2014 Wiley Periodicals, Inc.     

Chromosomal DNA balance in human stem cell line 4BL

Ploidy of a chromosome set and some regular structural aberrations in the new human 4BL cell line by passage 205 have been characterized in the previous cytogenetic studies. The purpose of this study was to investigate, using the array CGH and FISH methods, the nature of regular monosomies in particular homologous pairs. Structural aberrations were detected in all the chromosome pairs distinguished as monosomies according to classical cytogenetic analyses. The most notable alterations have been detected in chromosomes 2, 4, 10, 13, and 17. Massive genetic material losses were a probable cause for the monosomy of chromosomes 4, 10, 13, and 17. The monosomy of the second pair of chromosomes was caused by a substantial transformation in one of the homologs typified as multiple duplications and the formation of a derivative—der(2)t(2;?)(q21;?). The application of array CGH aided us in identifying the regions of structural aberrations in chromosomes 2, 4, 10, 13, and 17, that allowed a more accurate identification with the use of the multicolor FISH method. The obtained results confirm the hypothesis concerning a coordinated emergence of deletions and duplications and their stabilizing effect on transformed chromosomes.     

Biochemical indicators of oxygen poisoning]

Content of extra erythrocyte hemoglobin (EEH), total peroxidase activity (TPA), tseruloplasmin oxidase activity (TOA) and chemiluminescence intensity have been investigated in plasma. The dose-dependent changes of EEN, TPA, TOA are shown in experiments on the animals under hyperbaric oxygen (HBO) pressure (0.2, 0.3, 0.5, 0.7 MPa from 30 min. to 120 min.) and EEH, TPA--under hyperbaric air (1.1 MPa; 4 hours). All these parameters have been studied in patients treated with HBO for the assessment of HBO efficacy in the clinical investigations. These biochemical parameters may be used as informative tests of the functional state of the organism under HBO and hyperbaric air.     

Induction of mutations in mammalian cells by the action of live vaccinal strains of poliomyelitis virus

The attenuated strains' poliomyelitis virus induces mutagenesis in human and Chinese hamster cultured cells. The mutagenic action of the poliovirus is detected at chromosome and gene levels and directly depends on the multiplicity of cell infection. Possibilities for developing nonmutagenic antivirus vaccines are discussed.