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81.
A new method of the coating of isolated cell nuclei with additional phosphatidylcholine membranes is described. The additional membrane was visualized under the electron microscope using ferritin as a label. The coating diminished leakage of the content of the nuclei and restricted permeability of the nuclei for exterior macromolecules. 相似文献
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Microbiology - Solutions of SbF3 and NaSbF4 (50 and 100 mg/L) were found to have a toxic effect on soil microflora. At the final concentration of 50 mg/L, bacteria and microscopic fungi were... 相似文献
84.
Allen TD Rutherford SA Murray S Gardiner F Kiseleva E Goldberg MW Drummond SP 《Nature protocols》2007,2(5):1180-1184
Our previous work characterizing the biogenesis and structural integrity of the nuclear envelope and nuclear pore complexes (NPCs) has been based on amphibian material but has recently progressed into the analysis of tissue-culture cells. This protocol describes methods for the high resolution visualization, by field-emission scanning electron microscopy (FESEM), of the nucleus and associated structures in tissue culture cells. Imaging by fluorescence light microscopy shows general nuclear and NPC information at a resolution of approximately 200 nm, in contrast to the 3-5 nm resolution provided by FESEM or transmission electron microscopy (TEM), which generates detail at the macromolecular level. The protocols described here are applicable to all tissue culture cell lines tested to date (HeLa, A6, DLD, XTC and NIH 3T3). The processed cells can be stored long term under vacuum. The protocol can be completed in 5 d, including 3 d for cell growth, 1 d for processing and 1 d for imaging. 相似文献
85.
Allen TD Rutherford SA Murray S Sanderson HS Gardiner F Kiseleva E Goldberg MW Drummond SP 《Nature protocols》2007,2(5):1173-1179
This protocol details methods for the generation of cell-free extracts and DNA templates from the eggs and sperm chromatin, respectively, of the clawed toad Xenopus laevis. We have used this system with scanning electron microscopy (SEM), as detailed herein, to analyze the biochemical requirements and structural pathways for the biogenesis of eukaryotic nuclear envelopes (NEs) and nuclear pore complexes (NPCs). This protocol requires access to female frogs, which are induced to lay eggs, and a male frog, which is killed for preparation of the sperm chromatin. Egg extracts should be prepared in 1 d and can be stored for many months at -80 degrees C. Demembranated sperm chromatin should take only approximately 2-3 h to prepare and can be stored at -80 degrees C almost indefinitely. The time required for assembly of structurally and functionally competent nuclei in vitro depends largely on the quality of the cell-free extracts and, therefore, must be determined for each extract preparation. 相似文献
86.
M. I. Kiseleva S. P. Ermakova T. N. Zvyagintseva 《Russian Journal of Marine Biology》2015,41(6):468-478
The toxic effects of a water–ethanol extract of the brown alga Saccharina (= Laminaria) cichorioides and the isolated I1 and I2 proteins on egg fertilization and the development of embryos of the sea urchin Strongylocentrotus intermedius were revealed and studied. The protective effects of fucoidans and 1,3;1,6-β-D-glucans (laminarans, translam, and glucan II) that were isolated from the brown algae S. cichorioides and Fucus evanescens against the toxic impacts of the I1 and I2 proteins were examined. It was found that the lifespan of sea urchin embryos increased from 1.5 to 3 times in the presence of 1,3;1,6-β-D-glucans and fucoidans, whereas the I1 and I2 proteins decreased embryo viability by 2 times. Preadministration of polysaccharides completely neutralized the inhibitory effects of the proteins on developing embryos. It was also shown that a water–ethanol extract of S. cichorioides, derived I1 and I2 proteins, and fucoidans has a contraceptive effect. 相似文献
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Samsonova JV Rubtsova MYu Kiseleva AV Ezhov AA Egorov AM 《Biosensors & bioelectronics》1999,14(3):273-281
Competitive chemiluminescent immunoassay based on a combination of five antibodies was used in a combination with neural network to identify and estimate amounts of three cross-reacting s-triazines (atrazine, terbythylazine and ametryn). Antibodies with different cross-reactivity towards s-triazines were immobilized in separate wells an eight-well microtiter strip. Training of neural networks was carried out with four different learning procedures. The best topology for the data measured was a net with two hidden layers with ten neurons in the first and 15 in the second layer trained with the Schmidhuber method. s-Triazine classification of environmental samples containing various analyte mixtures was correct in 70-100% of all cases depending on the type of analyte. The test developed can be proposed as an alternative field test for multianalyte environmental monitoring. 相似文献
89.
90.
Differential effects of stretch and compression on membrane currents and [Na+]c in ventricular myocytes 总被引:1,自引:0,他引:1
Isenberg G Kazanski V Kondratev D Gallitelli MF Kiseleva I Kamkin A 《Progress in biophysics and molecular biology》2003,82(1-3):43-56
Mechano-electrical feedback was studied in the single ventricular myocytes. A small fraction (approximately 10%) of the cell surface could be stretched or compressed by a glass stylus. Stretch depolarised, shortened the action potential and induced extra systoles. Stretch activated non-selective cation currents (Ins) showed a linear voltage dependence, a reversal potential of 0 mV, a pure cation selectivity, and were blocked by 8 μM Gd3+ or 30 μM streptomycin. Stretch reduced Ca2+ and K+ (IK) currents. Local compression of broadwise attached cells activated IK but not Ins. Cytochalasin D or colchicin, thought to disrupt the cytoskeleton, suppressed the mechanosensitivity of Ins and IK. During stretch, the cytosolic sodium concentration increased with spatial heterogeneities, local hotspots with [Na+]c>24 mM appeared close to surface membrane and t-tubules (pseudoratiometric imaging using Sodium Green fluorescence). Electronprobe microanalysis confirmed this result and indicated that stretch increased total sodium [Na] in cell compartments such as mitochondria, nuclear envelope and nucleus. Our results obtained by local stretch differ from those obtained by end-to-end stretch (literature). We speculate that channels may be activated not only by axial but also by shear stress, and, that stretch can activate channels outside the deformed sarcomeres via second messenger. 相似文献