Investigation of the mechanism of temperature sensitivity of the electroreceptors of ampullae of lorenzini

In experiments on Black Sea skates (Raja clavata), the potential of the receptor epithelium of the ampullae of Lorenzini and spike activity of single nerve fibers connected to them were investigated during electrical and temperature stimulation. Usually the potential within the canal was between 0 and –2 mV, and the input resistance of the ampulla 250–400 k. Heating of the region of the receptor epithelium was accompanied by a negative wave of potential, an increase in input resistance, and inhibition of spike activity. With worsening of the animal's condition the transepithelial potential became positive (up to +10 mV) but the input resistance of the ampulla during stimulation with a positive current was nonlinear in some cases: a regenerative spike of positive polarity appeared in the channel. During heating, the spike response was sometimes reversed in sign. It is suggested that fluctuations of the transepithelial potential and spike responses to temperature stimulation reflect changes in the potential difference on the basal membrane of the receptor cells, which is described by a relationship of the Nernst's or Goldman's equation type.I. P. Pavlov Institute of Physiology, Academy of Sciences of the USSR, Leningrad. I. M. Sechenov, Institute of Evolutionary Physiology and Biochemistry, Academy of Sciences of the USSR, Leningrad. Pacific Institute of Oceanology, Far Eastern Scientific Center, Academy of Sciences of the USSR, Vladivostok. Translated from Neirofiziologiya, Vol. 12, No. 1, pp. 67–74, January–February, 1980.     

六种藓类植物茎的比较解剖学研究

通过对6种藓类植物,即褶叶青藓(Brachythecium salebrosum(Web.et Mohr.)B.S.G.)、湿地匐灯藓(Plagiomnium acutum(Lindb.)Kop.)、侧枝匐灯藓(Plagiomnium maximoviczii(Lindb.)Kop.)、大凤尾藓(Fissidensnobilis Griff.)、大羽藓(Thuidium cymbifolium(Doz.et Molk.)B.S.G.)和大灰藓(Hypnum plumaeforme Wils.)嫩茎和老茎的石蜡切片和显微观察发现,同一藓类植株的嫩茎和老茎,茎结构稳定,不同种藓类植物茎横切面具有不同特征.植物体茎横切面形状、表层细胞的层数、细胞大小和细胞壁厚薄、皮层细胞大小和形状、中轴的有无以及比例等特征可以作为藓类植物的分科分类依据之一.     

Principles of organization and evolution of systems of regulation of functions

Evolution of living organisms is closely connected with evolution of structure of the system of regulations and its mechanisms. The functional ground of regulations is chemical signalization. As early as in unicellular organisms there is a set of signal mechanisms providing their life activity and orientation in space and time. Subsequent evolution of ways of chemical signalization followed the way of development of delivery pathways of chemical signal and development of mechanisms of its regulation. The mechanism of chemical regulation of the signal interaction is discussed by the example of the specialized system of transduction of signal from neuron to neuron, of effect of hormone on the epithelial cell and modulation of this effect. These mechanisms are considered as the most important ways of the fine and precise adaptation of chemical signalization underlying functioning of physiological systems and organs of the living organism     

龙胆科药用植物化学成分的研究现状

龙胆科植物在我国的分布范围很广,且多数为药用植物,其多数种属的药用植物,至今其化学成分尚未被系统研究。综述了目前龙胆科药用植物的化学成分的研究现状及一般提取方法,对近年来发现的环烯醚萜及裂环烯醚萜类化合物进行了总结,为本科药用植物的更深入研究提供了参考。     

Non-Productive Binding of Substrates as One of Aspects of Substrate Specificity of Cholinesterases of Different Origin

Taking into account the phenomenon of non-productive binding of substrate, kinetic parameters of hydrolysis of acetylcholine (ACh) and its 13 derivatives with different structures of ammonium group by cholinesterase (ChE) of human erythrocytes, ChE of horse blood serum, and ChE of optic ganglia of the Pacific squid Todarodes pacificus are determined. A dependence is revealed of values of parameters of their enzymatic hydrolysis and parameters of the non-productive binding on the substrate structure and ChE nature. Effects of salts, LiCl, NaCl, KCl, MgCl₂, CaCl₂ and BaCl₂, on various kinetic parameters, including parameters of the non-productive binding of substrate, of enzymatic hydrolysis of iodides of ACh and N-acetoxyethylene-N-ethylpiperidinium under action of horse blood serum ChE are studied. Addition of the salts to the reaction mixture produced different effects on values of the catalytic center activity (a _c) and the Michaelis constant (K _M), depending on the cation nature and the substrate structure. At the same time, values of the a _c/K _M ratio that characterize to a degree the substrate affinity to the enzyme are equal to each other for two substrates differing in structure, regardless of the presence and nature of the studied cations. Parameters of the non-productive binding of N-acetoxyethylene-N-ethylpiperidinium iodide also depended on the salt nature; however, in that case, a question arises as to the correctness of the comparative analysis, when at determinations of the parameters the non-productive binding of ACh is ignored.     

Testing of one of the hypotheses of the inheritance of human fingerprints

A hypothesis claiming that the total phenotypes of finger patterns are controlled by three independent two-allele loci A, L and W with the complete dominance in each was analysed in this work. By means of the population genetics methods, non-accordance of the hypothesis examined to the observed distributions of total phenotypes A, L, W, AL, LW, ALW was revealed on the material of five populations (3060 men). On the basis of the segregation analysis method applied to 210 complete families (the total number of children-532), the hypothesis of one-locus heredity with the complete dominance of total phenotypes A and W was rejected, the reliability of this conclusion being 0.999 and 0.95, respectively. The hypothesis of the L pattern being genetically controlled by one locus with the complete dominance gave, when examined, the contradictory results, due to monomorphism of the character.     

Cause of Senescence of Nine Sorts of Flowers

The levels of endogenous phytohormones and respiratory rate in nine sorts of flowers such as Cymbidium faberi Rolfe, Nopalxochia ackermannii Kunth and others were investigated both at full bloom and senescence and meanwhile the effect of exogenous phytohormones on prolonging the blossoms and promoting ethylene production were tested. There is a high content of endogenous ethylene in all the long-lived flowere, about 3–16 folds higer than the short-lived ones. There is a high level of ABA at full blooming flowers of short-lived flowers, in which there is no or only some cytokinins in it, but the ratio of CTK (6BA+zeatin)/ABA is smaller(l.7). The endogenous ABA reached a much higher level at senescence in all nine sorts of flowers, so it is reasonable to consider that it is ABA which plays an important role of regulation in controlling flower's senescence. There is a much higher level of GA3 and zeatin in the long-lived flowers which is not demonstrated in the shortlived ones. The respiratory rate is one of the factors controtling the longevity of flowers, but it does not play a decided role. Application of 6BA and zeatin prolongs distinctly orchid’s longevity, however exogenous IAA through the promotive action on ethylene production, evidently extends the longevity of the flowers of the Nopalxochia ackermannii Kunth.     

Regulation of acidity of arable lands contaminated by Sr-90: analysis of cost of the averted doses of irradiation of population of Belarus

Results of researches on study of efficiency of soil acidity optimization on decrease of a collective doze from 90Sr to the population of Belarus are presented. On the basis of the "cost--benefit" analysis it is shown, that the savings for averted collective doze due to optimization of soil acidity of arable lands on cereals amount to 21-170 thousand US dollars per 1 man.-Sv depending on density of 90Sr soil contamination of districts of Belarus. It is established, that high effect on averting of collective doze 90Sr at cultivation of cereals can be expected at liming of sod-podsolic loamy sand soils with contamination density of 90Sr more than 12 kBq/m2, sand soils more than 16 kBq/m2, light loam soils more than 17 kBq/m2, at present time share of these lands in Belarus is about half from the area of the arable lands contaminated with radiostrontium - 86 thousand hectares.     

Determination of stoichiometry of radioiodination of proteins

A sensitive method for the detection of small quantities of hydrophobic antioxidant free radical scavengers such as butylatedhydroxytoluene (BHT) and butylatedhydroxyanisole (BHA) in aqueous samples is described. The procedure involves extraction of the hydrophobic free radical scavenger into an organic solvent phase, followed by the subsequent reaction of an aliquot of this extract with the stable cation radical tris(p-bromophenyl)amminium hexachloroantimonate (TBACA). In experiments with BHT and BHA, the loss of TBACA absorbance at 730 nm was found to be linearly proportional to the amount of antioxidant added, with quantities of BHT as small as 200 pmol being easily detectable. In aqueous suspensions of dimyristoylphosphatidylcholine vesicles, assays of the aqueous BHT concentration showed that BHT partitioned strongly into the membrane phase, achieving very high BHT/phospholipid ratios. For a given concentration of BHT, partitioning into the membrane phase was greater in large, multilamellar liposomes than in either small, single-walled vesicles or in purified rat brain synaptic vesicle membranes. Direct assay of BHT and BHA in phospholipid membranes, however, was complicated by a nonspecific interaction between TBACA and the phospholipid.     

Formulation of Statistical Equation of Motion of Blood

A general form of the statistical equation of motion of the blood is derived by averaging the motion of individual elements of the blood over a small volume in space. This equation can be transformed into an explicit form to find the constitutive equations of the blood provided the detailed motion of the plasma in some neighborhood of a suspended particle is known. As a demonstration of such transformation, the general form of the statistical equation of motion is applied to the suspension of sphere with a very low concentration to find the effective viscosity.     

Possible mechanisms of implementation of toxic potential of lipopolysaccharides of pathogenic bacteria

The significance of variability of biological properties of lipopolysaccharides (LPS) is discussed in the paper within the pathogenesis of infectious process. On the basis of an analysis of published data and of results of independent research of two microorganisms (Yersinia pestis and Francisella tularensis) a conclusion is made on that a biologically inert LPS form (with a weak cytokine-inducing ability, apirogenicity and non-toxicity etc.) is typical of highly pathogenic bacteria. It is suggested that the above phenomenon is biologically expedient. Presumably, the inert LPS transforms to the active form inside a sensitive host and, according to an infection stage, each of them being functionally significant. It is the inert status of LPS that enables the pathogens, at the initial stages, to surmount freely the humoral and cell barriers of host. As the infection progressively aggravates and the proliferation of bacteria modifies itself due to LPS micro- and macroorganisms, its chemical structure and biopolymer conformation change. Both modification mechanisms enhance the LPS toxic potential. In case of a sensitive host, such variations transform the biologically inert LPS into a toxically active form with its function of endotoxin being realized. There is no LPS modification in a host insensitive to such infection, which entails either recovery or prolonged persistence of the pathogen inside the microorganism.     

A quantitative estimation of degree of purity of preparations of subcellular structures

A method of mathematical treatment of the results of the analysis of enzymic activity of fractions has been suggested, allowing a quantitative estimation of both the degree of purity of fractions and the yield. Using this method the preparation of mitochondria, microsomes and lysosomes have been characterized. The method may also be used to elucidate the localization of some, not strictly organelle-specific enzymes of different subcellular structures.     

Comparative study of genomes of two species of flax by C-banding of chromosomes

C-banding patterns of the karyotypes of two closely related wild flax species, Linum austriacum L. (2n = 18) and Linum grandiflorum Desf. (2n = 16), were studied. The karyotypes of both species were similar in the chromosome morphology and size. In each species, metacentric and acrocentric chromosomes (1.7-4.3 microns) and one satellite chromosome were observed. In the karyotypes of the species studied, all homologous chromosome pairs were identified, and quantitative ideograms were constructed. Eight chromosome pairs in the two species had similar C-banding patterns. A low level of intraspecific polymorphism in the intercalary and telomeric C-bands was shown in both species. The results indicate that the genomes of two flax species originated from one ancestral genome with the main chromosome number of 8 or 9. Apparently, the doubling of chromosome number or loss of one chromosome with subsequent redistribution of the chromosome material in the ancestral form resulted in the divergence into two species, L. austriacum L. and L. grandiflorum Desf. A considerable similarity of chromosomes in these species provides evidence for their close phylogenetic relatedness, which makes it possible to place them in one section within the Linum genus.     

Identification of the site of sulfation of the fourth component of human complement

The alpha-chain of the fourth component of complement (C4) contains tyrosine sulfate (Karp, D.R. (1983) J. Biol. Chem. 258, 12745-12748). Here we have determined the site and stoichiometry of sulfation of C4 secreted by the human hepatoma-derived cell line Hep G2. C4 was labeled with [35S]sulfate and isolated from culture medium by immunoprecipitation. C4 digested with trypsin and chymotrypsin and analyzed by reverse-phase high-performance liquid chromatography contained a single sulfate-labeled peptide. Digestion of C4 with trypsin alone yielded two major sulfate-labeled peptides, suggesting that there may be some sequence variability in C4 near the site of sulfation. Sequential Edman degradation of tryptic peptides labeled with [3H]tyrosine and [35S]sulfate detected tyrosine residues at positions 5, 13, 16, and 18. Chymotrypsin cleaved 5 residues off the NH2-terminal end of tryptic peptides, yielding a peptide with tyrosine at positions 8, 11, and 13. Comparison of the position of tyrosine residues with the reported sequence of C4 identified the sites of sulfation as tyrosine residues at positions 738, 741, and 743 in the alpha-chain of C4. All 3 of these tyrosine residues appeared to be sulfated. When sulfation of C4 was partially inhibited by addition of catechol to culture medium, three different forms of the peptide were resolved by high-performance liquid chromatography, consistent with peptides containing 1, 2, or 3 sulfates. Comparison of the quantities of tyrosine and tyrosine sulfate in C4 which had been labeled with [3H]tyrosine and digested with Pronase also indicated that C4 contained an average of 2-3 residues of tyrosine sulfate/molecule. These results suggest that the biologically active form of the protein is sulfated.     

Principles of classification of life forms of plants

For classifying life forms of plants a proposal was made to use the principle of parallel divergence based on the hypothesis that life forms diverging to any degree preserve further the potential of evolving in a similar way, that is, in parallel series. Life forms of plants are divided into thirteen types corresponding to the nature of their basic metameres. Further, every type is divided into subtypes and sections according to the character of these metameres and then into smaller grades (classification units of the system of living forms corresponding to one trait and its evolutionary level) according to categories of traits: ramification, vegetative flexibility, rate of changes of metameres, types of habitat and environment. On the basis of the principle of parallel divergence scales of traits were constructed for each category. Corresponding to 26 paires of alternative traits 26 degrees of hierarchic classification were devised and within the limits of every type of life form there were 2(26) grades at the lowest rank. Separate systems were developed for single-celled and colonial forms.     

Classification of static behavior of a class of unstructured models of continuous bioprocesses

The stability characteristics of a class of unstructured models of continuous bioreactors are analyzed using elementary concepts of singularity theory and continuation techniques. The class consists of models for which the non-biomass product formation rate is linearly proportional to the utilization rate of limiting substrate. The kinetics expressions of cell growth and product synthesis are allowed to assume general forms of substrate and product. Global analytical conditions are derived that allow the construction of a practical picture in the multidimensional parameter space delineating the different static behavior these models can predict, including unique steady states, coexistence of non-trivial steady states with wash-out conditions, and multistability resulting from hysteresis. These general results are applied to specific examples of bioprocesses and allow the study of the effect of kinetic and operating parameters on the stability characteristics of these models.     

Studies of Initial Stages of Biocorrosion of Steel

Initial stages of corrosion of mild steel induced by Klebsiela rhinoscleromatis BO2 were studied in various media. The effect of the microorganism was detected 8–10 h after inoculation. The number of viable cells was virtually unchanged over one month in all media, but the corrosive activity of the strain decreased. The corrosive activity of microorganisms can be determined by spectrophotometry even after incubation for only 24 h. At a low level of organic substrate, even strong colonization with microorganisms does not inevitably result in significant damage to metals.     

Effects of overexpression of nutrient receptors on germination of spores of Bacillus subtilis

The rates of germination of Bacillus subtilis spores with L-alanine were increased markedly, in particular at low L-alanine concentrations, by overexpression of the tricistronic gerA operon that encodes the spore's germinant receptor for L-alanine but not by overexpression of gerA operon homologs encoding receptors for other germinants. However, spores with elevated levels of the GerA proteins did not germinate more rapidly in a mixture of asparagine, glucose, fructose, and K(+) (AGFK), a germinant combination that requires the participation of at least the germinant receptors encoded by the tricistronic gerB and gerK operons. Overexpression of the gerB or gerK operon or both the gerB and gerK operons also did not stimulate spore germination in AGFK. Overexpression of a mutant gerB operon, termed gerB*, that encodes a receptor allowing spore germination in response to either D-alanine or L-asparagine also caused faster spore germination with these germinants, again with the largest enhancement of spore germination rates at lower germinant concentrations. However, the magnitudes of the increases in the germination rates with D-alanine or L-asparagine in spores overexpressing gerB* were well below the increases in the spore's levels of the GerBA protein. Germination of gerB* spores with D-alanine or L-asparagine did not require participation of the products of the gerK operon, but germination with these agents was decreased markedly in spores also overexpressing gerA. These findings suggest that (i) increases in the levels of germinant receptors that respond to single germinants can increase spore germination rates significantly; (ii) there is some maximum rate of spore germination above which stimulation of GerA operon receptors alone will not further increase the rate of spore germination, as action of some protein other than the germinant receptors can become rate limiting; (iii) while previous work has shown that the wild-type GerB and GerK receptors interact in some fashion to cause spore germination in AGFK, there also appears to be an additional component required for AGFK-triggered spore germination; (iv) activation of the GerB receptor with D-alanine or L-asparagine can trigger spore germination independently of the GerK receptor; and (v) it is likely that the different germinant receptors interact directly and/or compete with each other for some additional component needed for initiation of spore germination. We also found that very high levels of overexpression of the gerA or gerK operon (but not the gerB or gerB* operon) in the forespore blocked sporulation shortly after the engulfment stage, although sporulation appeared normal with the lower levels of gerA or gerK overexpression that were used to generate spores for analysis of rates of germination.     

Features of Egg Cells of Living Representatives of Ancient Families of Ferns

Examination of two species of osmundaceous ferns, two speciesof marattialean, and one dipterid, all representative of fernswith a long fossil history, has shown that the egg cells possessnumerous large amyloplasts. The nuclei of these egg cells alsoproduce no vesicular or sheet-like protrusions during maturation.In these respects the egg cells of the ferns examined differsharply from those of more recent ferns such as Pteridium andDryopteris. The significance of these findings is discussed. Egg cells, amyloplast, Macroglossum, Todea, Osmunda, Dipteris