Microelectrode study of the cellular reactions of the taste bud in the frog Rana temporaria

Microelectrophysiological studies reveal two types of cells in the taste bud of frog which differ by the level of their membrane potential. During vertical implantation of microelectrode through the apical part of the taste bud, the potential difference in the upper layer amounts to 15 mV. Further implantation of the electrode results in a stepwise decrease of the potential difference up to 27 mV. Cells of the deeper layer are located 12-24 micron lower from the apical surface. Stimulation of cells by solutions of chemical substances is accompanied by cell depolarization, its amplitude being proportional to stimulus concentration. The steepness of depolarization depends on the modality of the stimulus, being maximum for salts. The data obtained suggest that cells of the second layer, with a higher resting membrane potential level, are taste ones.     

Microorganisms that break down alkyl sulfates

The following bacteria assimilating alkyl sulphates as a sole source of carbon and energy were isolated from various substrates: Pseudomonas, Achromobacter, Flavobacterium, Citrobacter, Enterobacter. The bacteria decomposed sodium dodecyl sulphate at a high rate, and some of them, industrial preparations of alkyl sulphates. The ability to assimilate alkyl sulphates was tested in 257 collection cultures belonging to different taxonomic groups. Alkyl sulphates were found to be decomposed by heterotrophous gram-negative rod-like bacteria belonging to different families and genera. The frequency of bacteria destroying alkyl sulphates at a high rate was found most often in the Pseudomonas genus.     

Shape and orientation of nuclei of embryonal fibroblast-like cells cultured on substrates with ordered relief]

Embryo fibroblasts of hamster, rat, mouse, and were cultured 24 hrs on polyvinylchloride plates with regular relief of grooves with cylindric surfaces in between. Most cells were accumulated on the middle part of spaces between the grooves, their nuclei were elongated and oriented in the direction of grooves. Nuclear elongation was assessed quantitatively by the ratio of long to short nuclear axes. Contact orientation was measured as deviation of the long nuclear axes from the grooves direction. Both contact orientation and elongation considered respectively as "orientation reaction" is maximal and the "form reaction", increased with increasing cylinder curvature (i. e. when the radii diminished from 333 to 61 mcm). Both reactions are well expressed in cultures of the human and (less distinctly) the rat cells. In murine cells, the "orientation reaction" is maximal and the "form reaction" is weak while for the hamster cells the opposite is true. Therefore, both types of reaction seem to be independent characteristics of cells.     

The peptide-dependent mechanisms of long-term posttetanic potentiation (the facts and a hypothesis)

In the article literature data and results of our studying of long-term potentiation (LTP) are analyzed the position of the proposed hypothesis that cells secrete during their activation into extracellular space a neuromodulatory factors, affecting on cell population and promoting the transformation of short-terms excitability in long-term one. It is considered the possible molecular-messengers particulated in development LTP. The neurophysiological and neurochemical evidences of the involvement neuropeptides as the key retrograde messengers are presented. It is analyzed the biological assay method as the adequate approach for study the role of endogenous neuropeptide in the LTP and analogous models. The possible mechanisms acting of neuropeptide by cells in LTP genesis are discussed.     

Ultrasound in phage display: a new approach to nonspecific elution

Libraries of phage-displayed random peptides are routinely used to identify target-binding peptides. Phages are commonly eluted in a nonspecific manner, especially if there are no available ligands of the particular target to use as competitors. However, the present study clearly demonstrates that nonspecific elution is not always able to break peptide-target interactions. To circumvent this we have developed an improved nonspecific elution strategy that uses ultrasound to release target-bound phages and enables selection of high-affinity clones in a single step.     

Sorption of wheat seed lectin by polyelectrolyte complexes of chitosan

The possible application of polyelectrolyte complexes (PEC) of chitosan and copolymers of maleic acid with N-vinylpyrrolidone, styrene, and ethylene and/or chitin cross-linked sorbents (CCLS) synthesized on the basis of PEC for sorption of wheat germ agglutinin (WGA) was studied. The synthesis of spherically granulated sorbents was shown. Compared to unmodified chitosan, there was a significant increase in sorption of WGA by the PEC: PEC, 2.5-fold, and CCLS, from 3.5-fold to 7-fold.     

Comparative characteristics of systemic and pulmonary hemodynamics during changes in the heart preloading

A greater degree of relative shifts in the systemic arterial pressure in enhancing the right heart pre-load as compared with its diminishing. A primary role of the compensation mechanisms of the enhanced systemic arterial pressure level. The main role in the compensation of integral shifts of the arterial pressure induced by changes in the heart pre-load was shown to belong to the vascular resistance both in the major and the minor circulation circles. An idea of a greater involvement of the capacity function of the vascular bed in the minor circulation circle as compared with that in the major circulation circle in systemic haemodynamic shifts in changes of the heart pre-load, has been advanced.     

RNA,unlike DNA,binds to aurintricarboxylic acid via covalent bonds: molecular-biological and spectroscopic evidence

A selective interaction of ATA with RNA, unlike DNA, when isolating nucleic acids from plant materials was established. The data concerning the binding strength of highly purified RNAATA and DNAATA preparations to nitrocellulose and nylon filters under conditions of high ionic strength are presented. The interrelation of ATA RNA-tropism and absence of adsorption capability of chemical modified RNAATA the backbone was observed. Using IR spectroscopy under the procedure of multi-broken complete light reflection, a formation of ATA and RNA complex was fixed via phosphoric-ether bond (P-O-C), which was absent in the case of DNAATA. The obtained data raise the problem of RNAATA application in molecular biology experiments.     

Construction of vector plasmids for the Plectonema boryanum cyanobacterium and creation,on such basis,of the vector-host system

The plasmid composition of the Plectonema boryanum Gom. Cyanobacterium, strain CALU 465, was analyzed. A small pSM1 plasmid, size 1.5, was chosen for genetic engineering. The physical map, constructed for the plasmid, was used to create the pSTS series, i.e. vector construction for the P. boryanum cyanobacterium. A method was selected and tested for the introduction of the vector into host cells. The needed orientation of pSM1 cyanobacterium plasmid within the vector as well as a possible role of its separate elements in inheriting the construction by host were defined.     

Affinity selection to papain yields potent peptide inhibitors of cathepsins L, B, H, and K

Endogenous cysteine proteases were given much attention lately, as their role in a variety of pathophysiological disorders became evident. Amongst them cathepsins, which are thought to be implicated in mediation of osteoporosis, cancer progression, atherosclerosis, and many other conditions, are of considerable interest as drug targets. In the presented work, papain was chosen as a model cysteine protease and panning protocol was optimized for selection of papain-binding phage-displayed peptides from a commercially available combinatorial peptide library. Different selection strategies were applied in order to select high-affinity binders. Ultimately, five cyclic peptides (CNWAAGYNCGGGS-NH2, CWSMMGFQCGGGS-NH2, CWEWGGWHCGGSS-OH, CNWTLGGYKCGGGS-NH2 (all cyclized through formation of intramolecular disulphide bond), and GNWTLGGYKGG (cyclized head-to-tail)) were synthesized and tested for inhibitory activity towards papain and human cathepsins L, B, H, and K. The peptides possess inhibitory constants in the low micromolar to mid-nanomolar range and exhibit certain selectivity for different lysosomal cysteine proteases included in this study.