Hydroxynonenal-generated crosslinking fluorophore accumulation in Alzheimer disease reveals a dichotomy of protein turnover

Lipid peroxidation generates reactive aldehydes, most notably hydroxynonenal (HNE), which covalently bind amino acid residue side chains leading to protein inactivation and insolubility. Specific adducts of lipid peroxidation have been demonstrated in intimate association with the pathological lesions of Alzheimer disease (AD), suggesting that oxidative stress is a major component of AD pathogenesis. Some HNE-protein products result in protein crosslinking through a fluorescent compound similar to lipofuscin, linking lipid peroxidation and the lipofuscin accumulation that commonly occurs in post-mitotic cells such as neurons. In this study, brain tissue from AD and control patients was examined by immunocytochemistry and immunoelectron microscopy for evidence of HNE-crosslinking modifications of the type that should accumulate in the lipofuscin pathway. Strong labeling of granulovacuolar degeneration (GVD) and Hirano bodies was noted but lipofuscin did not contain this specific HNE-fluorophore. These findings directly implicate lipid crosslinking peroxidation products as accumulating not in the lesions or the lipofuscin pathways, but instead in a distinct pathway, GVD, that accumulates cytosolic proteins.     

Compartmentalized energy transfer in cardiomyocytes: use of mathematical modeling for analysis of in vivo regulation of respiration.

The mathematical model of the compartmentalized energy transfer system in cardiac myocytes presented includes mitochondrial synthesis of ATP by ATP synthase, phosphocreatine production in the coupled mitochondrial creatine kinase reaction, the myofibrillar and cytoplasmic creatine kinase reactions, ATP utilization by actomyosin ATPase during the contraction cycle, and diffusional exchange of metabolites between different compartments. The model was used to calculate the changes in metabolite profiles during the cardiac cycle, metabolite and energy fluxes in different cellular compartments at high workload (corresponding to the rate of oxygen consumption of 46 mu atoms of O.(g wet mass)-1.min-1) under varying conditions of restricted ADP diffusion across mitochondrial outer membrane and creatine kinase isoenzyme "switchoff." In the complete system, restricted diffusion of ADP across the outer mitochondrial membrane stabilizes phosphocreatine production in cardiac mitochondria and increases the role of the phosphocreatine shuttle in energy transport and respiration regulation. Selective inhibition of myoplasmic or mitochondrial creatine kinase (modeling the experiments with transgenic animals) results in "takeover" of their function by another, active creatine kinase isoenzyme. This mathematical modeling also shows that assumption of the creatine kinase equilibrium in the cell may only be a very rough approximation to the reality at increased workload. The mathematical model developed can be used as a basis for further quantitative analyses of energy fluxes in the cell and their regulation, particularly by adding modules for adenylate kinase, the glycolytic system, and other reactions of energy metabolism of the cell.     

Development and characterization of antibodies against aflatoxins

A panel of ten monoclonal antibodies against aflatoxins B1, B2, and G2 was produced and comprehensively characterized. The affinity and cross reactivity of these antibodies were determined using the methods of direct, indirect, and competitive ELISA. The structures of monoclonal antibody genes were comprehensively studied and the variable and constant regions of the antibody genes were cloned and sequenced. Sequencing analysis confirmed the results of isotyping the light and heavy antibody chains obtained by ELISA. Variable and constant fragments of the antibody genes were cloned into a bicistron expression vector for the recombinant Fab-fragment for one of the antibodies expressed in Escherichia coli and purified. Thus, data were obtained that can be useful for the development of an aflatoxin detection system on the basis of the described monoclonal antibodies and the creation of recombinant antibodies with changed parameters of specificity using protein engineering methods.     

Disturbances in the intestinal microflora and immune system in children with vitiligo

A total of 91 children, aged 3-16 years, with vitiligo were examined. These examinations showed that the total number of T lymphocytes decreased irrespective of the degree of intestinal dysbacteriosis. The average number of T suppressors increased as dysbiotic changes in the intestine became more profound. The amount of natural killers, B lymphocytes, as well as the content of IgG and IgA (p < 0.001), increased irrespectively of the degree of intestinal dysbacteriosis. Thus the unbalance of the immunity system and dysbiotic changes in the intestine of children having vitiligo were Inter-related.     

Generation and Characterization of a Neutralizing Monoclonal Antibody Against Rabies Virus

Russian Journal of Bioorganic Chemistry - Rabies is a zoonotic disease, for which effective treatment methods after the onset of clinical symptoms have not been developed yet. Polyclonal sera, both...     

Effect of preliminary chronic irradiation and alpha-tocopherol on the frequency of chromosome aberrations in mouse bone marrow cells, induced by exposure to acute gamma-irradiation

The incidence of chromosome aberrations in bone marrow cells of femur did not exceed the spontaneous one in CBA mice exposed, during 70 days, to gamma-radiation at dose--rates of 33.7-35.8 nA/kg and cumulative dose of 2.75 Gy. A single acute exposure of intact animals to a dose of 2.98 Gy increased significantly the mutation level. Preirradiation with small doses increased the resistance of hereditary structures to sublethal radiation doses. Exogenous alpha-tocopherol (0.06 mg/20 g mass) protected the genetic apparatus of cells from total-body irradiation and was an additional factor decreasing the mutation level after acute exposure of mice at the background of long-term irradiation with small doses.     

Glycinebetaine protects the D1/D2/Cytb559 complex of photosystem II against photo-induced and heat-induced inactivation

The presence of 1.0 mol/L glycinebetaine during isolation of D1/D2/Cytb559 reaction centre (RC) complexes from photosystem II (PSII) membrane fragments preserved the photochemical activity, monitored as the light-induced reduction of pheophytin and electron transport from diphenylcarbazide to 2.6-dichlorophenol-indophenol.-Glycinebetaine also protected the D1/D2/Cytb559 complexes against strong light-induced damage to the photochemical reactions and the irreversible bleaching of beta-carotene and chlorophyll. The presence of glycinebetaine also enhanced thermotolerance of the D1/D2/Cytb559 complexes isolated in the presence of 1.0 mol/L betaine with an increase in the temperature for 50% inactivation from 29 degrees C to 35 degrees C. The results indicate an increased supramolecular structural stability in the presence of glycinebetaine.     

Development and properties of recombinant proteins based on the broadly neutralizing antibody to influenza A virus

We studied the possibility of using a broadly neutralizing anti-influenza A antibody as a module for the development of different protein constructs for diagnostics. For this purpose, we constructed two recombinant proteins—a Fab-fragment of the antibody and Fab-mCherry, which is a hybrid of the Fab-fragment and the mCherry fluorescent protein. Both proteins were expressed in Escherichia coli cells and purified in a functionally active state from culture medium. The antibody Fab-fragment was shown to bind all 11 tested strains of the influenza A H1N1 and H3N2 subtypes. A stronger binding was observed for group I hemagglutinins; this correlates with the immunochemical profile of the parental antibody. Comparison of the dissociation constants of complexes of the antibody Fab-fragment and Fab-mCherry with A(H1N1)/Solomon Islands/03/06 virus particles demonstrated that the attachment of the mCherry protein did not interfere with the antigen-binding properties of the antibody Fab-fragment.