Acid-Sensitive Outwardly Rectifying Anion Channels in Human Erythrocytes

Acid-sensitive outwardly rectifying anion channels (ASOR) have been described in several mammalian cell types. The present whole-cell patch-clamp study elucidated whether those channels are expressed in erythrocytes. To this end whole-cell recordings were made in human erythrocytes from healthy donors treated with low pH and high osmotic pressure. When the pipette solution had a reduced Cl⁻ concentration, treatment of the cells with Cl⁻-containing normal and hyperosmotic (addition of sucrose and polyethelene glycol 1000 [PEG-1000] to the Ringer) media with low pH significantly increased the conductance of the cells at positive voltages. Channel activity was highest in the PEG-1000 media (95 and 300 mM PEG-1000, pH 4.5 and 4.3, respectively) where the current–voltage curves demonstrated strong outward rectification and reversed at −40 mV. Substitution of the Cl⁻-containing medium with Cl⁻-free medium resulted in a decrease of the conductance at hyperpolarizing voltages, a shift in reversal potential (to 0 mV) and loss of outward rectification. The chloride currents were inhibited by chloride channels blockers DIDS and NPPB (IC₅₀ for both was ~1 mM) but not with niflumic acid and amiloride. The observations reveal expression of ASOR in erythrocytes.     

实时荧光定量PCR及其在传染性疾病检测中的应用

实时荧光定量PCR技术被广泛应用于实验研究、临床检测中。与普通的PCR相比,实时荧光定量PCR技术具有特异性强、灵敏度高、重复性好、定量准确、速度快、全封闭反应等优点。我们综述了实时荧光定量PCR技术的原理、定量方法,及其在传染性疾病检测研究中的应用。     

Taking account of macromolecule conformation dynamics in the analysis of luminescent probe signals

A mathematical model of electron excitation energy transport between molecular probes sorbed on the polymeric chain in solution was proposed. The kinetics of the process was described in terms of the conception of stochastic changes in macromolecule conformation. The results of computer simulation and the analytical expressions obtained in the framework of the perturbation theory for the cases of low transfer rate and/or fast conformation motion of the macrochain are presented. A channel of nonlinear deactivation as a result of binary annihilation of closely-spaced excited centers was considered. Expressions for the effective rate of mutual quenching and delayed annihilation fluorescence of the probe were obtained. Time dependencies of typical luminescent signals and parameteric curves of relative fluorescence quantum yield are presented.     

Genetic Analysis of Drosophila melanogaster X-Chromosome Neurodegenerative Mutants Induced by Ethyl Methansulfonate and Nitrosoethylurea

In a series of Drosophila mutants with changes in the brain structure, some characters (reduced life span, behavioral changes, and neuronal loss in various brain regions) resemble symptoms observed in human patients with neurodegenerative diseases. In addition, similar specific phenotypes shared by different species suggest that common mechanisms underlie degeneration of their nerve cell. This study reports the results of a genetic analysis of new X-chromosome mutants with neurodegenerative changes in brain structure, which were induced by chemical mutagenesis. According to complementation test, all mutants were divided into three complementation groups, in which the life span and dynamics of neurodegenerative changes were studied. The life span of Drosophila melanogaster flies was found to depend on the state of their nervous system.     

Early manifestations of the effect of Salmonella endotoxin on the antioxidizing enzyme systems of the liver and intestines in the rat

A study was made of the effect of salmonellosis endotoxin (SE) on the activity of glutathione transferase (GT), glutathione peroxidase (GP-GTB and GP-H2O2), glutathione reductase (GR) and superoxide dismutase (SOD) in cytosols of the rat jejunal mucosa and liver. The activity of all the test enzymes of both the small intestine and liver was marked by drastic changes at the early stages of SE action. Thus, the activity of SOD and GP-H2O2 in the liver decreased after 30 min or 1 h of endotoxin action, respectively. In the jejunal mucosa, the activity of GP-H2O2 and SOD dropped after 4 h of SE action. GT in the jejunum remained unchanged, whereas in the liver, it was activated. The activity of GR and GP-GTB in the liver and jejunum was dissimilar. The causes and consequences of the abnormalities of the antioxidant enzymatic system and the role they play in the pathogenesis of salmonellosis intoxication are discussed.     

Novel ways to prevent proteolysis — prophytepsin and proplasmepsin II

The recently determined crystal structures of two aspartic proteinase zymogens, prophytepsin from barley and proplasmepsin II from the malarial parasite Plasmodium falciparum, have provided new insights into zymogen inactivation. Prophytepsin shows a variation of the mechanism of inhibition used by the well-known gastric aspartic proteinase zymogens, whereas proplasmepsin II uses a completely new mode of inactivation.     

RAPID SCREENING FOR SALMONELLA IN FISHMEAL BY ENRICHMENT-IMMUNOASSAY

We previously described an enrichment-immunoassay utilizing a T6 monoclonal antibody capture enzyme-linked immunosorbent assay. Here we evaluated it for the rapid screening for Salmonella in fishmeal obtained from the national Animal and Plant Quarantine service in the People's Republic of China. In this method, the number of Salmonella present is first expanded by appropriate enrichment cultures, and the pathogens are then directly detected by the T6 immunoassay. In a total of 94 enrichment cultures of fishmeal, we obtained an overall concordance of 98% between the results obtained in parallel by this method and by conventional test method. The positive prediction by this method was 92% and the negative prediction was 100%. The turn around time for the new test was 27 h which is a significant improvement from the turn around time exceeding 96 h required for the conventional test method. This test proved to be compatible with the routine work flow in the practical setting of a quarantine laboratory.     

The content of phospholipids and free fatty acids in the sarcoplasmic reticulum membranes in the early stage of an x-ray radiation lesion

One and 24 h following single X-irradiation (0.21 C/kg) of rabbit hind leg the content of free fatty acids and phospholipid lysoforms increased in the sarcoplasmic reticulum (SR) membrane of skeletal muscles. The results obtained are important in estimating the mechanisms of action of ionizing radiation on the structural and functional properties of SR.