Polymorphism of smolts of pink salmon <Emphasis Type="Italic">Oncorhynchs gorbuscha</Emphasis> in the Indera River (Kola Peninsula)

Pink salmon introduced into the White Sea started to exploit as spawning grounds middle and upper reaches of the river 20 years after its appearance in the Indera River. As a result of this, the migration pathway of smolts and late smolts appeared in addition to early smolts. The intraspecies polymorphism of smolts is confirmed by differences of early and late smolts by body length and weight, migration dates, food spectrum, and indices of stomach fullness. The food spectra of late juveniles of pink salmon coincide with those of parr of Atlantic salmon Salmo salar and of brown trout S. trutta. Greater abundance of late migrants of pink salmon may cause competition of these species for food.     

Localization and volume of the derivatives of the prechordal plate of the cephalic gut in vertebrates]

In order to determine the localization and volume of the prechordal lamina derivatives the initial stages of histogenesis of the cephalic gut epithelium lining were studied in embryos of chickens and mammals (rabbits, rats, mice) in early terms of the formation of the fore-part of their digestive tube. It has been established that the derivatives characteristics of the prechordal lamina such as the cephalic end of the chordal, larval mesodermal somites, are formed by the real enterocelic means only from the entodermal epithelium of the Seessel's pouch walls which is the most cranial end of the cephalic gut. In other parts of the dorsal wall of the pharynx, the more of the oesophagus, the prechordal lamina derivatives fail to be determined. This fact shows that the localization of the prechordal lamina coincides with the disposition of the Seessel's pouch lining, the histological nature of its material being identical to the entoderm.     

Mathematical Modeling of Open States in DNA Molecule Depending on the Deuterium Concentration in the Surrounding Liquid Media at Different Values of Hydrogen Bond Disruption Energy

The effect of the deuterium concentration in the surrounding liquid medium on the appearance of open states between the nitrogen bases of a double-stranded DNA molecule was investigated. It is shown that the nature of this effect depends on the magnitude of the energy of the hydrogen bond break.     

ERp29 is an essential endoplasmic reticulum factor regulating secretion of thyroglobulin

ERp29 is a ubiquitously expressed endoplasmic reticulum (ER) protein, which is found in the folding complexes of several secretory proteins in the ER. In our previous work, it was suggested that ERp29 function is critical for the folding/secretion of thyroglobulin (Tg), a major secretory product of thyroid cells. Current work is an attempt to substantiate this assumption by answering the question whether the secretion of Tg can be regulated through the manipulation of ERp29 expression in the FRTL-5 rat thyroid cells. Indeed, transient overexpression of ERp29 resulted in twofold enhancement of the Tg secretion whereas the RNAi-mediated ERp29 silencing led to the attenuation of the Tg export. Mutational analysis has suggested two loci that might be involved in the ERp29-Tg interactions: the interdomain linker including Cys157, an amino acid, which is important for the structural integrity of the C-terminal domain and an uncharged surface on the N-terminal domain flanked by Tyr64 and Gln70.     

ERp29 triggers a conformational change in polyomavirus to stimulate membrane binding

Membrane penetration of nonenveloped viruses is a poorly understood process. We have investigated early stages of this process by studying the conformational change experienced by polyomavirus (Py) in the lumen of the endoplasmic reticulum (ER), a step that precedes its transport into the cytosol. We show that a PDI-like protein, ERp29, exposes the C-terminal arm of Py's VP1 protein, leading to formation of a hydrophobic particle that binds to a lipid bilayer; this reaction likely mimics initiation of Py penetration across the ER membrane. Expression of a dominant-negative ERp29 decreases Py infection, indicating ERp29 facilitates viral infection. Interestingly, cholera toxin, another toxic agent that crosses the ER membrane into the cytosol, is unfolded by PDI in the ER. Our data thus identify an ER factor that mediates membrane penetration of a nonenveloped virus and suggest that PDI family members are generally involved in ER remodeling reactions.     

The Effect of an Alternating Magnetic Field and Silver Nanoparticles on the Spectral Characteristics of an Aqueous Solution of Human Serum Albumin

Biophysics - In this paper, we discuss experimental data obtained during study of the effect of a low-frequency alternating magnetic field on the conformational transitions of human serum albumin...     

A Mathematical Model for Basepair Opening in a DNA Double Helix

In this paper, we consider a mathematical model that draws an analogy between a DNA molecule and a mechanical system consisting of two chains of interconnected pendulums. This model is designed to explore the dynamics of the system determined by rotational movements of nucleobases around a double-stranded pentose phosphate backbone. The workability of this model is assessed with respect to various factors: inhomogeneity of the chain of nucleobases, the properties of bonds in complementary pairs, and the formation of open states. It has been shown that simplified models for averaging the characteristics of the chain of nucleobases or simplification of the type of hydrogen bond in their complementary pairs influence the type of solution significantly, impairing the validity of the results. Therefore, the approach to the solution of rotational DNA molecule dynamics developed here is more consistent with its actual biomechanics. It is shown that the emergence of open states within nucleobase pairs and restoration of the closed structure may occur in the tested mathematical model.