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41.
D. N. Lapshin 《Entomological Review》2015,95(9):1155-1165
Individual characteristic frequencies and directional sensitivity of the Johnston’s organ auditory receptors were measured in the midges Chironomus plumosus L. using the method of positive feedback stimulation: responses of receptors recorded with a glass microelectrode from their axons in the antennal nerve were amplified and fed to the stimulating speaker. With the amplitude and the stimulating signal phase properly adjusted, the whole feedback loop fell into auto-excitation with the frequency of oscillations close to the characteristic frequency of the receptor. Three separate groups of receptors were found with mean frequencies of 180, 221, and 264 Hz. These groups differ in their directional properties: the low-frequency receptors are mostly sensitive dorsoventrally, while the directional maxima of mid- and high-frequency ones are combined to provide equal sensitivity in the plane perpendicular to the flagellum. Our data suggest that in Chironomidae a single Johnston’s organ together with the antenna can provide spatial localization of conspecific sounds and also perform the initial stages of frequency analysis. 相似文献
42.
Background
The rapid and accurate identification of species is a critical component of large-scale biodiversity monitoring programs. DNA arrays (micro and macro) and DNA barcodes are two molecular approaches that have recently garnered much attention. Here, we compare these two platforms for identification of an important group, the mammals. 相似文献43.
L. A. Volkova A. B. Burgutin O. P. Soldatova T. A. Ezhova P. V. Lapshin 《Russian Journal of Plant Physiology》2005,52(3):374-380
A tolerance to paraquat (PQ) of plants and cell cultures of Arabidopsis thaliana mutants, nfz18 and nfz24, obtained by chemical mutagenesis and selected by their tolerance to norflurason was demonstrated. This tolerance to PQ was manifested in less active peroxidation of lipids (POL), which was assessed by the content of thiobarbituric acid-reactive substances, and in a less degree of plant and callus damages, which was accompanied by a higher activity of superoxide dismutase and other antioxidant enzymes. A capability of norflurason-tolerant mutants to cross-adaptation toward PQ and activation of antioxidant enzymes indicate a genetically determined activation of the antioxidant systems, resulting in improved mutant tolerance to these inducers of oxidative stress. The nfz24 mutant was much more sensitive to hypothermia than wild-type plants and nfz18 mutants, which was expressed in a higher level of POL in plants and calluses and in a more rapid decrease in the suspension cell viability of this mutant. A similarity in the responses of plants and derived heterotrophic cultures to PQ and hypothermia indicates that, in these A. thaliana mutants, adaptation to these types of stresses occurs mainly at the cellular level. Possible reasons of increased sensitivity to hypothermia of the nfz24 mutant, which was more tolerant to the inducers of oxidative stress, PQ and norflurason, are discussed.__________Translated from Fiziologiya Rastenii, Vol. 52, No. 3, 2005, pp. 421–429.Original Russian Text Copyright © 2005 by Volkova, Burgutin, Soldatova, Ezhova, Lapshin. 相似文献
44.
The average electron thermal energies in the emission flux from the electrode into the plasma, ? 1, and from the plasma toward the electrode, ? 2, are determined for the cases of large and small values of the coefficient of kinetic reflection. It is shown that these energies vary within the ranges 0.5k B T c < ? 1 < 2k B T c and 0.5k B T e < ? 2 < 2k B T e , where T c and T e are the temperatures of the cathode and plasma electrons, respectively. The obtained values can be used to formulate the boundary conditions for the hydrodynamic equations at the electrode or a dielectric wall. 相似文献
45.
N. N. Sazhina P. V. Lapshin N. V. Zagoskina E. I. Korotkova V. M. Misin 《Russian Journal of Bioorganic Chemistry》2014,40(7):771-776
A study of the biological, including the antioxidant, activity of various medicinal plants with the aim of searching for the most active sources of biologically active compounds among them is, at present, of interest. In the present work, a comparative analysis of the antioxidant activity of juices from 14 Kalanchoe species, measured by the ammetric, voltammetric, and chemiluminescence methods has been performed. Among the samples examined, two members of the Kalanchoe genus were shown to have the highest antioxidant activity: Kalanchoe scapigera and K. rhombopilosa. They may appear to be richer sources of biologically active compounds compared with the currently used Kalanchoe species. 相似文献
46.
Using method of registration of electrical potentials caused by chemical stimulation of the skin surface of the head of the
carp Cyprinus carpio, the effect of prolonged olfactory deprivation (3, 9, and 12 months after operation) and partial blinding of anosmiated fish
(9 months) on the sensitivity thresholds of external chemoreceptors was studied. It was found that, 3 months following anosmiation,
the thresholds decreased by orders of 0.1–0.5, and, after 9 and 12 months, they decreased by orders of 0.1–0.8 depending on
the kind of the chemical stimulus and the zone of registration. The highest increase in the sensitivity of skin chemoreceptors
was recorded in anosmiated fish deprived also of object vision, by orders of 0.3–1.5. The results obtained indicate the existence
of a close functional relationship between the olfactory and visual systems, on the one hand, and the skin chemosensory system,
on the other hand. The compensatory processes taking place in these systems in the case of the loss of one of them have an
adaptive pattern and are directed at provision of reliability of behavioral contacts and survival of fish in the environment. 相似文献
47.
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49.
The absorption spectrum of fluorescent probe--a cholesterol analog cholesta-5,7, 9(11)-trien-3 beta-ol has a vibrational structure with the maximum 326 nm. Its fluorescence spectra maximum is 370 nm. The localization of the probe in lipoproteins of high, low and very low density and in lipid spheres is studied. There are measured the areas, which occupied one molecule of cholesterol and phosphatidyl choline on the surface of lipid spheres and the radius of the lipid spheres. The localization of the probe in lipoproteins and lipid spheres is determined. The areas which occupied one molecule of phosphatidyl choline on the surface of lipid sphere is equal to the same area in mono- and bilayers. Cholesterol has the same condensing action on phosphatidyl choline in lipid spheres as in mono- and bilayers. All the probe molecules are localized on the surface of lipid spheres and lipoproteins and the B-ring of the molecule is immersed on 1.3 +/- 0.2 nm relative to polar groups. The hydroxyl group of cholesterol is arranged near the carbonyl group of phospholipid and the formation of the H-bond between these groups is possible. 相似文献
50.
F. G. Baksht S. V. Gavrish V. B. Kaplan V. F. Lapshin A. M. Martsinovsky 《Plasma Physics Reports》2010,36(13):1199-1202
Results of theoretical and experimental studies of the optical spectrum of a pulse-periodic high-pressure cesium discharge
are presented. The results of calculations are in good agreement with experimental data. The possibility of creating an efficient
light source based on recombination emission from the discharge plasma is demonstrated. The formation mechanisms of the continuous
spectrum of discharge radiation are considered. 相似文献