Decreased collagen stability as a response to the loss of structural integrity of thyroid cartilage

The thermal behavior, birefringence properties, and the biochemical composition of thyroid cartilage tissues have been studied. The hyaline cartilage, which was visualized as a quasi-isotropic medium, was composed of type II collagen, which did not denature at temperatures up to 100 degrees C. However, in hyaline cartilage digested by trypsin, the denaturation of collagen occured at 60 degrees C. Collagen fibers in the perichondrium were composed of type I and II collagen and formed a highly organized anisotropic structure (birefringence about 4.75 x 10(-3)) with a melting temperature of about 65 degrees C. The temperature of collagen denaturation in perichondrium in the whole system perichondrium-hyaline cartilage increased up to 75 degrees C, indicating the immobilization of perichondrium collagen by the extracellular matrix of the hyaline constituent.     

The Regulatory Effect of Low-Intensity Radiation in the Near-Infrared Region on the Early Development of Zebrafish (<Emphasis Type="Italic">Danio rerio</Emphasis>)

The effects of exposure to low-intensity continuous radiation in the red and near-infrared regions of the spectrum, as well as to infrared pulsed radiation, on the early development of zebrafish (Danio rerio) were studied. It was found that the use of continuous radiation at the red and infrared wavelengths (633 nm, 930 nm, dose 24 mJ/m²) leads to accelerated development of the embryo. In contrast, exposure to low-intensity single pulsed infrared radiation (864 nm) in the entire range of the doses studied (2.4–2400 mJ/cm2) negatively affected the early development of zebrafish, resulting in a significant dose-dependent delay in the hatching time of embryos and a reduction in the body length of larvae.     

An essential saccharide binding domain for the mAb 2C7 established for Neisseria gonorrhoeae LOS by ES-MS and MSn

A study of bacterial surface oligosaccharides were investigated among different strains of Neisseria gonorrhoeae to correlate structural features essential for binding to the MAb 2C7. This epitope is widely expressed and conserved in gonococcal isolates, characteristics essential to an effective candidate vaccine antigen. Sample lipooligosaccharides (LOS), was prepared by a modification of the hot phenol-water method from which de-O-acetylated LOS and oligosaccharide (OS) components were analyzed by ES-MS-CID-MS and ES-MSnin a triple quadrupole and an ion trap mass spectrometer, respectively. Previously documented natural heterogeneity was apparent from both LOS and OS preparations which was admixed with fragments induced by hydrazine and mild acid treatment. Natural heterogeneity was limited to phosphorylation and antenni extensions to the alpha-chain. Mild acid hydrolysis to release OS also hydrolyzed the beta(1-->6) glycosidic linkage of lipid A. OS structures were determined by collisional and resonance excitation combined with MS and multistep MSn which provided sequence information from both neutral loss, and nonreducing terminal fragments. A comparison of OS structures, with earlier knowledge of MAb binding, enzyme treatment, and partial acid hydrolysis indicates a generic overlapping domain for 2C7 binding. Reoccurring structural features include a Hepalpha(1-->3)Hepbeta(1-->5)KDO trisaccharide core branched on the nonreducing terminus (Hep-2) with an alpha(1-->2) linked GlcNAc (gamma-chain), and an alpha-linked lactose (beta-chain) residue. From the central heptose (Hep-1), a beta(1-->4) linked lactose (alpha-chain), moiety is required although extensions to this residue appear unnecessary.      

Influence of Low-Intensity Electromagnetic Field on Some Biological Parameters of Freshwater Crustaceans <Emphasis Type="Italic">Daphnia magna</Emphasis> Straus

We have studied the effects of a low-intensity electromagnetic field (EMF) with a frequency of 30 MHz in continuous-wave and amplitude-modulation modes on Daphnia magna in a laboratory culture. The exposure range is from 10 to 10000 s. We examine the parental generation (irradiated) and three subsequent (F₁–F₃) generations (nonirradiated). It is found that irradiation does not affect the total fertility of any specimen in four generations (P–F₃), except for continuous EMF exposure for 10000 s, which increases the total fertility in generations F₂ and F₃ by 23 and 43%, respectively. Electromagnetic radiation has a significant impact on offspring quality and causes fetal abnormalities in the offspring of all generations.     

The effect of infrared laser irradiation on the growth of human melanoma cells in culture

Biophysics - Low-intensity laser irradiation exerts effects on various biological objects and is currently exploited in various branches of medicine. From a practical point of view, irradiation in...     

Compatibility of cells of the nervous system with structured biodegradable chitosan-based hydrogel matrices

Hydrogel matrices for cell cultivation have been generated by two-photon laser polymerization of unsaturated chitosan derivatives and methacrylated hyaluronic acid. The adhesive and toxic properties of the matrices have been assessed, and the matrices have been shown to have a good compatibility with primary hippocampal cell cultures. The formation of morphologically normal neural networks by cells of the nervous system cultured on the surface of hydrogel matrices has been observed. The metabolic status of dissociated hippocampal cells cultured on the matrices was similar to that of the control cultures, as shown by the results of MTT reductase activity assay. Thus, matrices based on unsaturated polysaccharide derivatives crosslinked by laser irradiation showed good compatibility with differentiated cells of the nervous system and considerable potential for use in neurotransplantation.     

The influence of low-intensity electromagnetic radiation of the 10-meter range on morphological and functional indices on Daphnia magna straus

The effects of continuous and amplitude-shift-keying low-intensity electromagnetic field (EMF) of the 10-m range with on–off cycling on fertility, offspring quality, and linear body size was studied in the planktonic crustacean Daphnia magna. Single exposure of 1-day-old crustaceans was shown to affect their reproductive characteristics, causing fetal abnormalities in the offspring and the linear dimensions of the body.

     

Effect of self-association on the structural organization of partially folded proteins: inactivated actin

The propensity to associate or aggregate is one of the characteristic properties of many nonnative proteins. The aggregation of proteins is responsible for a number of human diseases and is a significant problem in biotechnology. Despite this, little is currently known about the effect of self-association on the structural properties and conformational stability of partially folded protein molecules. G-actin is shown to form equilibrium unfolding intermediate in the vicinity of 1.5 M guanidinium chloride (GdmCl). Refolding from the GdmCl unfolded state is terminated at the stage of formation of the same intermediate state. An analogous form, known as inactivated actin, can be obtained by heat treatment, or at moderate urea concentration, or by the release of Ca(2+). In all cases actin forms specific associates comprising partially folded protein molecules. The structural properties and conformational stability of inactivated actin were studied over a wide range of protein concentrations, and it was established that the process of self-association is rather specific. We have also shown that inactivated actin, being denatured, is characterized by a relatively rigid microenvironment of aromatic residues and exhibits a considerable limitation in the internal mobility of tryptophans. This means that specific self-association can play an important structure-forming role for the partially folded protein molecules.