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排序方式: 共有264条查询结果,搜索用时 15 毫秒
21.
Serum stimulation of stationary cultures of Chinese hamster ovary cells CHO-K1 (clone 773) is accompanied by sustained increase in ouabain-sensitive rubidium (potassium) influx which results in the elevation of intracellular potassium content from 0.5-0.6 to 0.7-0.8 mmole per gram of protein. Cytofluorometric studies of serum-stimulated CHO-773 cultures have shown that the intracellular potassium increase is necessary for successful G1----S progression. The elevation of intracellular potassium was found to occur simultaneously with the cellular protein growth. Cycloheximide (10 micrograms/ml) does not influence the early Na,K-ATPase activation induced by serum; however, it abolishes the sustained increase of both rubidium influx and intracellular potassium content. In serum stimulated cells ouabain increases the potassium efflux; this ouabain effect is not observed after S phase, when rubidium (potassium) influx decreases and intracellular potassium content stops growing. 相似文献
22.
S. S. Efimova O. S. Ostroumova V. V. Malev L. V. Schagina 《Cell and Tissue Biology》2011,5(4):397-405
The effect of the membrane dipole potential (φ
d
) on conductance and the steady-state number of functioning channels formed by cyclic lipodepsipeptide syringomycin E (SRE)
in bilayer lipid membranes made from phosphocholine and bathed in 0.4 M solution of sodium salts of aspartate, gluconate,
and chloride was shown. The φ
d
value varied with the introduction of phloretin to membrane bathing solutions, which reduces φ
d
and RH 421, which increases φ
d
. It was established that, in all studied systems, an increase in the membrane dipole potential caused a decrease in the steady-state
number of open channels. In systems containing sodium salts of aspartate (Asp) or gluconate (Glc), changes in the number of
functioning channels are one order lower than those of systems that contain sodium chloride. At the same time, the conductance
(g) of single SRE channels in the membranes bathed in NaCl solution increases with increase in φ
d
and in the systems containing NaAsp or NaGlc the conductance of single channels does not depend on the φ
d
. The latter is due to the lack of cation/anion selectivity of the SRE channels in these systems. The different channel-forming
activity of SRE in the experimental systems is determined by the gating charge of the channel and the partition coefficient
of the dipole modifiers between the lipid and aqueous phases. 相似文献
23.
Summary The EcoK restriction of unmodified phage is 1000-fold alleviated in Escherichia coli grown in the presence of base analogs 2-aminopurine (2AP) and 5-bromouracil (5BU). 2AP treatment of bacteria affects specificially the type I restriction systems (EcoA, EcoB, EcoD and EcoK) and does not influence type II (EcoRI) and type III (EcoP1) restriction. 2AP-induced alleviation of restriction occurs in bacteria which are deficient in the SOS response (recA and lexA) and mismatch repair (mutH, mutL and mutS) and can be distinguished from the alleviation of restriction observed in dam
- strains. We suggest that mismatches induced by 2AP and 5BU may function as an inducing signal for the alleviation of restriction observed in the presence of base analogs. 相似文献
24.
25.
E E Dubinina L A Sal'nikova L F Efimova P A Evarestov 《Ukrainski? biokhimicheski? zhurnal》1986,58(3):31-36
The superoxide-dismutase (EC 1.15.1.1) activity was revealed in blood plasma after its successive treatment with alcohol, chloroform and one- or two-substituted phosphate. Its value is the highest when treating plasma with KH2PO4. The boiling of the supernatant liquid obtained after addition of K2HPO4 leads to a complete loss of the activity. The treatment of plasma with KH2PO4 provides higher stability of the enzyme to thermal actions. The analysis of EPR-spectra has shown the presence of different complex compounds of copper ions in the supernatant liquid. Certain experiments with the use of aqueous solutions of CuCl2 and histidine have shown that Cu2+ inhibits the superoxide-dismutase activity in samples treated with KH2PO4 and increases it in samples treated with K2HPO4. 相似文献
26.
Anastasiia Golius Leonid Gorb Olexander Isayev 《Journal of biomolecular structure & dynamics》2019,37(1):247-255
Computational studies of the potential biological impact of several energetic compounds were performed. The most commonly used explosives were considered in the present studies: trinitrotoluene (TNT), 2,4-dinitrotoluene (2,4-DNT), 2,4-dinitroanisole (DNAN), and 5-Nitro-2,4-dihydro-3H-1,2,4-triazol-3-one (NTO). The effect of such factors as ionic strength and presence of DMSO in the water solution on the structure of the membrane were considered using the POPC lipid bilayer as an example. Molecular dynamics (MD) simulations revealed that, even on a short-time scale, the influence of those additives is noticeable, and therefore those factors should always be taken into account. The MD and the COSMOmic approaches were used to elucidate the ability of the energetic compounds to penetrate the living cell. Calculated free energy profiles and partitioning coefficients revealed distributions of the compounds in the lipid bilayer as well as an overall ability to enter the cell. MD in this case provides a better representation of the free energy profile, while the COSMOmic approach works better to predict log(Klipw) values. The effect of the functional group was observed for the profiles that were obtained using the MD method. 相似文献
27.
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29.
V M Arablinski? O Iu Efimova A Kh Trakhtenberg G A Frank S V Korenev 《Vestnik rentgenologii i radiologii》1991,(5):5-10
The paper is devoted to analysis of the investigation and treatment of 137 patients with histologically verified lung sarcoma. X-ray was the chief method of primary detection. A classification, singling out 3 types, was developed: peripheral (82.6%), central (16%) and disseminated (1.4%). The first one included nodular (76%) and pneumonia-like (6.6%) types of changes, the second one--endobronchial changes (11%), peribronchial (2.9%) and exobronchial nodular (2.1%) changes. The developed roentgenosemeiotics made it possible to diagnose malignancy in 72% of the patients, indicating its nonepithelial nature in 36%. 相似文献
30.