Redox processes in allergic reactions of the delayed type to microbial antigens]

The influence of common allergic response of delayed type to brucellosis antigen on the processes of glycolysis and dehydrogenase activity of Krebs' cycle in guinea pigs' blood and organs was studied. Along with inhibitory activity of four dehydrogenases investigated there was a depression of the glucolysis processes connected with reduction of the lactate, pyruvate content, and with depression of the LDH activity. An increase of the anaerobic fractions and lowering of aerobic fractions content and of the spectrum excess was seen in the isoenzyme LDH spectrum.     

The immunochemical characteristics of allergens

Modern approaches to the standardization of allergens require the use of not only biological methods, but also a wide range of physicochemical and immunological ones. To obtain Soviet standard samples, the optimum spectrum of methods for their characterization, evaluation and comparison with international standard samples should be definitely selected. After the preliminary study of a number of allergens by different immunochemical methods a set of such methods, including different kinds of electrophoresis, isoelectrofocusing, immunoblotting, etc., are proposed, these methods being considered obligatory for obtaining Soviet standard samples of allergens.     

Estimation of Uptake of Humic Substances from Different Sources by Escherichia coli Cells under Optimum and Salt Stress Conditions by Use of Tritium-Labeled Humic Materials

The primary goal of this paper is to demonstrate potential strengths of the use of tritium-labeled humic substances (HS) to quantify their interaction with living cells under various conditions. A novel approach was taken to study the interaction between a model microorganism and the labeled humic material. The bacterium Escherichia coli was used as a model microorganism. Salt stress was used to study interactions of HS with living cells under nonoptimum conditions. Six tritium-labeled samples of HS originating from coal, peat, and soil were examined. To quantify their interaction with E. coli cells, bioconcentration factors (BCF) were calculated and the amount of HS that penetrated into the cell interior was determined, and the liquid scintillation counting technique was used as well. The BCF values under optimum conditions varied from 0.9 to 13.1 liters kg⁻¹ of cell biomass, whereas under salt stress conditions the range of corresponding values increased substantially and accounted for 0.2 to 130 liters kg⁻¹. The measured amounts of HS that penetrated into the cells were 23 to 167 mg and 25 to 465 mg HS per kg of cell biomass under optimum and salt stress conditions, respectively. This finding indicated increased penetration of HS into E. coli cells under salt stress.Humic substances (HS) are natural organic compounds comprising 50 to 90% of the organic matter of peat, coal, and sapropel (i.e., sludge that accumulates at the bottom of lakes), as well as of the nonliving organic matter of soil and water ecosystems (9, 34, 53). Being the products of stochastic synthesis, HS are characterized as polydispersed substances having elemental compositions that are nonstoichiometric and structures which are irregular and heterogeneous. Thus, it is not possible to assign an exact structure to HS. Instead, they are operationally defined using a model structure predicated on available compositional, structural, functional, and behavioral data: a model structure containing all the same basic structural units and types of reactive functional groups (46). HS have been demonstrated to contain a large amount of residues resembling the original building blocks (aromatic subunits, amino acids, carbohydrates, etc.) (51) as well as polyphenolic components with nonhydrolyzable C-C and ether bonds (51, 16). Since humic matter is a complex mixture of organic substances, HS yield extremely high polydispersity values (i.e., the ratio of weight-average molecular weight to the number-average molecular weight [M_w/M_n]), which vary within the range of 1.64 to 4.40 (38). These extremely high polydispersity values mean that even though they yield relatively high values of molecular weight, HS contain a low-molecular-weight fraction.HS are known to play important roles in protecting microorganisms and higher plants from climatic and technogenic stresses, such as pollution, draught, UV irradiation, and pathogen and viral infections (2, 22, 31). However, mechanisms underlying protective functions of these natural systems are still poorly understood. The primary reason for that is a lack of experimental tools for tracking uptake and distribution of natural organic mixtures in living cells and tissues, which makes it extremely difficult to link structure and functions in systems of such high complexity. Besides, predicting HS behavior in biological systems is extremely arduous, as HS are complex mixtures with a number of concurrent properties, such as polyanionic and polyelectrolyte character, hydrophilic and hydrophobic moieties, different functional groups, etc.The most straightforward hypothesis is that the biological activity of HS depends on both hydrophobic and hydrophilic characteristics of structural components (56). This hypothesis implies that the biological effects of HS are connected to membrane activity (12, 44, 56). Sorption of HS onto cells is the best documented phenomenon; numerous studies include phytoplankton (7, 15, 36, 57), isolated fish gill cells (7), bacteria (13, 14, 27, 57), fungi (60), and plants (12, 31, 44). This suggests that the sorption of HS onto biological membranes is a general process, but very few quantitative estimates are available (13, 36). Moreover, the penetration of HS into the living cells is still questionable, and to the best of our knowledge, only one study has reported a direct estimate of HS uptake by microorganisms (10).The main complication that arises in the study of the interactions of HS with living cells is the lack of a reliable analytical technique for determination of HS in the presence of biomolecules (e.g., proteins, lipids, and saccharides). To overcome the problem, radioactive labeling of HS is being used widely for this purpose. However, the reported studies deal predominantly with synthetic rather than with native humic materials (49, 50, 58). This is because of the approaches used for the radioactive labeling of the humics used in those studies, which involve either composting of a labeled precursor (e.g., ¹⁴C-glucose) with a soil sample (17) or the synthesis of model polymeric compounds. The polymeric compounds either are synthesized by enzyme-mediated oxidative polymerization of phenolic compounds, which is initiated by adding H₂O₂ in the presence of horseradish peroxidase (19), or proceed spontaneously in the presence of oxygen or other oxidants at an alkaline pH (48). When phenolics are polymerized with nonaromatic precursors (e.g., proteins, peptides, amino acids, carbohydrates, and amino sugars), the resulting humic-like materials are very similar to natural HS (19). These methods can be used for producing both ¹⁴C- and ¹⁵N-labeled humic-like substances. Their substantial disadvantage is that the resulting materials are similar but not identical to natural HS. Given high structural heterogeneity and irregularity inherent within HS, the availability of a broad set of labeled humic materials identical to their natural counterparts is a prerequisite for disclosing the mechanism of their interactions with living organisms on the cellular and organismal levels.The goal of this work was to study the behavior of humics in a simple microbial system using humic substances from various natural sources. For this purpose, six natural humic materials with different molecular features and properties were isolated from various natural sources and then labeled with tritium using a technique developed in previous studies (3, 4). A strain of the well-studied bacterium Escherichia coli was used as a model bacterial culture. The molecular weight of humics is quite high and is generally considered to be the leading factor restricting their uptake by living cells. In view of our study, prokaryotic bacteria seemed to be the most appropriate model, as recent evidence suggests that size differences among eukaryotic homologues of integral membrane proteins are consistently larger than their bacterial counterparts (8).To demonstrate the potential strengths of using tritium-labeled HS for biological study, uptake of HS by bacterial cells under stress conditions was also studied. One way in which bacteria respond to environmental change is to regulate cell membrane permeability. Thus, another goal of this work was to monitor changes in HS-bacterium interactions under salt stress conditions. For quantitative indicators, bioconcentration factors, maximum adsorption, and the amount of HS that penetrated into the cell interior were used.     

Evolution of the CD163 family and its relationship to the bovine gamma delta T cell co-receptor WC1

Background  

The scavenger receptor cysteine rich (SRCR) domain is an ancient and conserved protein domain. CD163 and WC1 molecules are classed together as group B SRCR superfamily members, along with Spα, CD5 and CD6, all of which are expressed by immune system cells. There are three known types of CD163 molecules in mammals, CD163A (M130, coded for by CD163), CD163b (M160, coded for by CD163L1) and CD163c-α (CD163L1 or SCART), while their nearest relative, WC1, is encoded by a multigene family so far identified in the artiodactyl species of cattle, sheep, and pigs.     

Mismatch repair

Specific repair systems are activated in response to the DNA damage. Mismatch repair protects the genome of prokaryotic and eukaryotic cells from lesions that appear during process of DNA replication or are induced by mutagenic factors. The methyl directed mismatch repair distinguishes the new strand from the old strand by the hemi-methylated state of the DNA and controls the fidelity of genetic information after homologous recombination. The very short patch repair restores the mismatches at the sites with nucleotide sequence CC(W/T)GG. The "8-oxoG" pathway is independent of the hemi-methylated state of the DNA, and removes the oxidated nucleotides from the genome of prokaryotes and eukaryotes. Mutations in genes of mismatch repair enhance the process of mutagenesis in prokaryotic cell, and are the reason for the development of the colon cancer in humans. The mechanisms of mismatch repair and the role of defective repair proteins in mutagenesis and carcinogenesis are discussed in this review.     

MNT Optimization for Intracellular Delivery of Antibody Fragments

We studied the possibility of optimizing modular nanotransporters (MNTs) for the intracellular delivery of antibody fragments into the nuclei of cells of a specified type. Basic MNT with a reduced size retaining the desired functions was obtained, and the principal possibility of obtaining an MNT carrying an antibody fragment by microbiological synthesis was shown.     

Heterogeneity of collagen molecules types I and II according to their resistance to proteolysis

Study of the effects of pepsin treatment on soluble collagens type I of the skin and collagens type II of the costal cartilage of healthy subjects revealed the presence of two classes of molecules differing in the stability of their three-helical structure. In collagen molecules possessing a low stability (their number may amount to 20-30%) within the temperature range of 4-30 degrees C pepsin causes a split-off of N-terminal sites with the formation of short chains, i.e., alpha 1(I), alpha 2(II), and alpha 1(II), whereas at higher temperatures (33 degrees C for collagens type I and 37 degrees C for collagens type II) a complete degradation of these molecules takes place. It was found that collagens types I and II molecules contain a high number of three-helical sites with a high susceptibility to pepsin. The putative functional role of structural heterogeneity of collagen molecules is discussed.     

Impairment of homologous chromosome synapsis in meiosis in rye <Emphasis Type="Italic">Secale cereale</Emphasis> L. Caused by a recessive mutation of the <Emphasis Type="Italic">sy18</Emphasis> gene

Expression and inheritance of the sy18 mutation causing impairment of synapsis homology were studied. It was established that the abnormal phenotype is determined by a recessive allele of the sy18 gene. Univalents and multivalents are observed in homozygotes for this mutant allele. According to the electron microscopic analysis of synaptonemal complexes in mutants, homologous synapsis occurs together with nonhomologous synapsis. The sy18 gene was found to have no allelism with asynaptic genes sy1 and sy9 and with genes sy10 and sy19 causing, like sy18, disturbances in synapsis homology.     

Properties of human chorion neuraminidase

Some properties of human chorion neuraminidase were studied. Using n-butanol, a solubilized preparation of neuraminidase with specific activity considerably exceeding the initial activity of the chorion homogenate was obtained. The pH-dependence and substrate specificity of the enzyme towards low molecular weight (sialylglycolipids and sialylglycoproteins) native substrates were examined. These properties of solubilized neuraminidase from human chorion were found to be similar to those of the lysosomal enzyme from other animal tissues. The results abtained are consistent with the properties of neuraminidase from native chorion and amniotic fluid cell cultures. Based on the substrate specificity of the solubilized enzyme, it was found that chorion biopsy specimens could be used for prenatal diagnosing of sialidoses and mucolipidoses IV. Some properties of solubilized human chorion beta-galacotosidase were studied.