Effect of adaptation to central highlands conditions on active avoidance conditioning and its retention after emotional pain stress

The generation of conditioned reflex of active avoidance (CRAA) and its retention after emotional stress were studied in different groups of rats. The degree of conditioned reflex of active avoidance in pre-adapted rats was higher than in non-adapted animals. However, the degree of CRAA maintenance was independent of the character of CRAA fixation and the rats' adaptability after 1 and 3 exposures to emotional stress. In a usual degree of conditioned reflex fixation its maintenance was higher in rats living on the plain than in low-mountain rats (adapted and non-adapted).     

Coherence and phase analysis of theta-oscillations in the septohippocampal system during seizures

Interrelations of the hippocampus and medial septal area (MSA) in the theta band (4-8 Hz) were studied during seizures produced by electrical kindling in waking guinea pigs. Field activity (EEG) was analyzed using the wavelet transform. A decrease in coherence of theta-oscillations in the hippocampus and MSA was observed during seizures. Phase analysis showed that in the beginning of kindling the MSA led in phase, but after formation of the pathological focus, MSA lagged the hippocampus. The data may contribute to understanding mechanisms of temporal lobe epilepsy.     

Water scaffolding in collagen: Implications on protein dynamics as revealed by solid‐state NMR

Solid‐state NMR studies of collagen samples of various origins confirm that the amplitude of collagen backbone and sidechain motions increases significantly on increasing the water content. This conclusion is supported by the changes observed in three different NMR observables: (i) the linewidth dependence on the ¹H decoupling frequency; (ii) ¹³C CSA changes for the peptide carbonyl groups, and (iii) dephasing rates of ¹H‐¹³C dipolar couplings. In particular, a nearly threefold increase in motional amplitudes of the backbone librations about C‐C^α or N‐C^α bonds was found on increasing the added water content up to 47 wt%D₂O. On the basis of the frequencies of NMR observables involved, the timescale of the protein motions dependent on the added water content is estimated to be of the order of microseconds. This estimate agrees with that from wideline T₂ ¹H NMR measurements. Also, our wideline ¹H NMR measurements revealed that the timescale of the microsecond motions in proteins reduces significantly on increasing the added water content, i.e., an ～15‐fold increase in protein motional frequencies is observed on increasing the added water content to 45 wt% D₂O. The observed changes in collagen dynamics is attributed to the increase in water translational diffusion on increasing the amount of added water, which leads to more frequent “bound water/free water” exchange on the protein surface, accompanied by the breakage and formation of new hydrogen bonds with polar functionalities of protein. © 2013 Wiley Periodicals, Inc. Biopolymers 101: 246–256, 2014.     

Isolation of highly active preparations of sarcoplasmic reticulum and Ca2-dependent ATPase from cardiac muscle]

A microsomal preparation with a high ability for Ca2+ uptake has been isolated from pigeon heart. A method of further purification of Ca2+-accumulating system of heart, based on the ability of sarcoplasmic reticulum for the energy-dependent Ca2+ accumulation in the presence of oxalate, has been developed. Upon centrifugation in the gradient of sucrose and KCl concentration the fragments of sarcoplasmic reticulum, rendered "heavy" by calcium oxalate, can be separated from foreign cell membranes. The main component of heart "calcium pump" is Ca2+-dependent ATPase (making up to about 50% of all proteins of the purified reticulum), having a molecular weight of 100.000--105.000. Specific activity of heart Ca2+-ATPase as well as the ability of purified heart sarcoplasmic reticulum for Ca2+ uptake are only slightly less than those of the skeletal muscle reticulum. The data obtained suggest that heart sarcoplasmic reticulum may be efficient for providing heart muscle relaxation.     

Recombinant Fragment of the Extracellular Domain of Human Desmoglein 3 Fused with the Fc-Fragment of Human IgG1 Selectively Adsorbs Autoreactive Antibodies from the Sera of Pemphigus Patients

Doklady Biochemistry and Biophysics - Using the recombinant second fragment of the extracellular domain (EC2) of human desmoglein type 3 (Dsg3) as an affinity ligand, an immunosorbent was obtained...     

Hair diameter distribution in sheep interspecies hybrids

Hair diameter distribution was studied in wild sheep species (argali—Ovis ammon, mouflon—O. Musimon; domestic sheep—O. aries) and their hybrids. In wild species and their hybrids, rather distinctly separated subpopulations of thin (underwool) hairs (10–22 μm diameter) and thick (kemp) hairs (85–302 μm) were detected, and intermediate diameters were rare. In domestic sheep, the kemp subpopulation was very poor, not distinctly separated from the underwool, while maximal hair diameter was <150 μm. In wild × domestic crosses, the kemp subpopulation was clearly expressed, shifted to lower diameter range, and maximal diameters was <200 μm. The same restriction was found in two-month-old wild species lambs compared with adults.