Recombinant small heat shock protein from <Emphasis Type="Italic">Acholeplasma laidlawii</Emphasis> increases the <Emphasis Type="Italic">Escherichia coli</Emphasis> viability in thermal stress by selective protein rescue

In both prokaryotes and eukaryotes, the survival at temperatures considerably exceeding the optimum is supported by intense synthesis of the so-called heat shock proteins (HSPs), which act to overcome the adverse effects of heat stress. Among mycoplasmas (class Mollicutes), which have significantly reduced genomes, only some members of the Acholeplasmataceae family possess small HSPs of the α-crystallin type. Overproduction of a recombinant HSP IbpA (Hsp20) from the free-living mycoplasma Acholeplasma laidlawii was shown to increase the resistance of Escherichia coli to short-term heat shock. It has been long assumed that IbpA prevents protein aggregation and precipitation thereby increasing viability of E. coli cells. Several potential target proteins interacting with IbpA under heat stress were identified, including biosynthetic enzymes, enzymes of energy metabolism, and components of the protein synthesis machinery. Statistical analysis of physicochemical properties indicated that IbpA interaction partners significantly differ in molecular weight, charge, and isoelectric point from other members of the E. coli proteome. Upon shortterm exposure to increased temperature, IbpA was found to preferentially interact with high-molecularweight proteins having a pI of about 5.1, significantly lower than the typical values of E. coli proteins.     

Microwave generation by a superluminal source at limiting current densities

It is well known that high-power directed wideband electromagnetic radiation in the microwave range can be generated by a superluminal pulse of the electron emission current. The operation of a simple emitting element driven by a superluminal current pulse and consisting of an accelerating diode with a photocathode and a source of ionizing radiation that initiates electron emission from the cathode is considered. It is shown that the parameters of an elementary superluminal source obey scaling relations that are determined by the growth rate of the electron emission current from the photocathode and the parameters of the accelerating diode. The limiting anode current density and the limiting values of the characteristics of electromagnetic radiation achievable in such a system are determined. The effect of the finite dimensions of the accelerating system on the parameters of the emitter is investigated, and the spatiotemporal characteristics of the generated electromagnetic fields are obtained.     

Dielectric parameters of ascitic and pleural fluids in the microwave range in different nosologies

The dielectric parameters of ascitic and pleural fluids formed in the human body in oncological and nononcological diseases of different nosology have been estimated in the range between 400 MHz and 1.2 GHZ. The dependence of refractive and absorption indices of ascitic and pleural liquids on the signal frequency and mass concentration of dissolved substances was found. Common regularities and distinctions in the behavior of their dielectric properties were revealed.     

DNA methylation-associated colonic mucosal immune and defense responses in treatment-na?ve pediatric ulcerative colitis

Inflammatory bowel diseases (IBD) are emerging globally, indicating that environmental factors may be important in their pathogenesis. Colonic mucosal epigenetic changes, such as DNA methylation, can occur in response to the environment and have been implicated in IBD pathology. However, mucosal DNA methylation has not been examined in treatment-naïve patients. We studied DNA methylation in untreated, left sided colonic biopsy specimens using the Infinium HumanMethylation450 BeadChip array. We analyzed 22 control (C) patients, 15 untreated Crohn’s disease (CD) patients, and 9 untreated ulcerative colitis (UC) patients from two cohorts. Samples obtained at the time of clinical remission from two of the treatment-naïve UC patients were also included into the analysis. UC-specific gene expression was interrogated in a subset of adjacent samples (5 C and 5 UC) using the Affymetrix GeneChip PrimeView Human Gene Expression Arrays. Only treatment-naïve UC separated from control. One-hundred-and-twenty genes with significant expression change in UC (> 2-fold, P &lt; 0.05) were associated with differentially methylated regions (DMRs). Epigenetically associated gene expression changes (including gene expression changes in the IFITM1, ITGB2, S100A9, SLPI, SAA1, and STAT3 genes) were linked to colonic mucosal immune and defense responses. These findings underscore the relationship between epigenetic changes and inflammation in pediatric treatment-naïve UC and may have potential etiologic, diagnostic, and therapeutic relevance for IBD.     

Cineangiographic diagnosis of an aneurysm of the membranous part of the heart septum

Altogether 20 patients with aneurysm of the cardiac membranous septum (AMS) were examined. Biplane cineangiocardiography (CACG) of the left ventricle was performed in the left oblique position permitting the detection of AMS in 17.8% of the patients with the suspected interventricular septal defect (IVSD). Heart diseases were observed in all the patients, in 90% they were accompanied by IVSD in the cardiac wall. AMS regular contours and a wide base were signs of true AMS. A narrow base and irregular shape were indicative of false AMS. Slight aortic transposition was noted in 1/4 of the patients with AMS.     

Morphofunctional condition of kidney after disruption of its lymphatic drainage

Dimentions of the renal corpuscle, proximal and distal convoluted tubules have been studied in the dog kidney, normal and the morphofunctional state of the organ after cutting and ligation of its different lymphatic vessels (4 series of experiments in 158 dogs). The observations have been performed in 0.5, 1, 3, 10-160 days of the experiments. Histological, histochemical and morphometrical methods have been applied; the residual nitrogen in blood has been determined. During early stages, disturbances in the pathways of lymph outflow result in development of edema and albumin saturation of interstitium. granular distrophy of convoluted tubules epithelium in the kidneys. In 40-160 days stromal diffuse sclerosis of the medullary substance develops. The changes described and deterioration of the nitrogen-excretory function of the organ are especially pronounced after the disturbance in the pathways of lymph outflow are combined with a simultaneous extirpation of the contralateral kidney. Under these conditions the processes of the renal compensatory hypertrophy slow down. The morphofunctional changes after the disturbance in the pathways of lymph outflow from the compensatory hypertrophied kidney are the least pronounced.     

Amide I band of IR spectrum and structure of collagen and related polypeptides

The infrared amide I band of collagens (rat and cod skin) and related compounds (polyproline, polyglycine, and polytripeptides) was studied. Assignment of amide I-band components for polyproline II and polytripeptides (Gly-Pro-Pro)_n and (Gly-Pro-Gly)_n in the solid state and water solution was made. Three amide I components observed in the polypeptide spectra were attributed to three different peptide CO groups in each triplet. On the basis of this assignment, the interpretation of the amide I multicomponent structure in collagen and isomorphous oligo- and polypeptides was attempted. The ordering of intra- and intermolecular hydrogen bonds involving peptide CO groups in collagen and related compounds was discussed.     

The development of modified human Hsp70 (HSPA1A) and its production in the milk of transgenic mice

The production of major human heat shock protein Hsp70 (HSPA1A) in a eukaryotic expression system is needed for testing and possible medical applications. In this study, transgenic mice were produced containing wild-type human Hsp70 allele in the vector providing expression in the milk. The results indicated that human Hsp70 was readily expressed in the transgenic animals but did not apparently preserve its intact structure and, hence, it was not possible to purify the protein using conventional isolation techniques. It was suggested that the protein underwent glycosylation in the process of expression, and this quite common modification for proteins expressed in the milk complicated its isolation. To check this possibility, we mutated all presumptive sites of glycosylation and tested the properties of the resulting modified Hsp70 expressed in E. coli. The investigation demonstrated that the modified protein exhibited all beneficial properties of the wild-type Hsp70 and was even superior to the latter for a few parameters. Based on these results, a transgenic mouse strain was obtained which expressed the modified Hsp70 in milk and which was easy to isolate using ATP columns. Therefore, the developed construct can be explored in various bioreactors for reliable manufacture of high quality, uniform, and reproducible human Hsp70 for possible medical applications including neurodegenerative diseases and cancer.