By osmotic lysis of pinocytic vesicles we were able to inject ricin or ricin A chain directly into the cytosol of Chinese hamster ovary cells. The lag time of 1 to 2 h before the onset of the inhibition of protein synthesis by ricin in intact cells was reduced to 15 to 30 min by this method. Preincubation of cells with a low concentration of nigericin, which was shown earlier to enhance the cytotoxicity of ricin, had no effect under this condition. Direct transfer of either intact ricin or the ricin A subunit by osmotic lysis of pinocytic vesicles into the cytosol of the ricin-resistant CHO mutant cell line 4-10 rendered the mutant 4-10 cells as sensitive to ricin as the CHO pro wild-type cells. Both the lag time and the rate of inhibition of protein synthesis in the wild-type and mutant cell lines after the introduction of ricin by osmotic lysis of pinocytic vesicles were the same. These results indicate that injection of ricin into the cytosol by osmotic lysis of pinosomes bypasses the internalization defect in the mutant cell line.
This paper presents the budget method of the Mars-earth communication link.The calculation models of Mars atmosphere loss, Mars sandstorm loss, solar scintillation loss, earth atmosphere absorption; rainfall loss and hot body noise are studied.The propagation characteristics of electromagnetic waves in Mars atmosphere are analyzed and modeled by the characteristics of the propagation of analogous waves in the Earth's atmosphere.Ultimately, we found that the surface of the radio waves propagation environment is ideal, with less attenuation loss.Especially, the calculate model of solar scintillation loss and rainfall loss is simulated, and the simulation results are consistent with the actual statistical results, which proves the rationality of the calculate model.At last, an example of Mars-earth communication link budget is given.With the procedure, we can get one of the most important parameters of the link--Carrier to Noise Ratio, and we know the bit signal to noise ratio required by the right BER, then the maximum code rate of the link can be got.This paper has some reference to the design of Mars communication link.
Internalization of ricin into Chinese hamster ovary cells has been investigated. Combined treatment with galactose and pronase at 0 degrees C resulted in a complete release of surface-bound [125I]ricin into the media. Galactose-pronase-resistant cell-bound [125I]ricin represents internalized ricin molecules inside the cells. The internalization process is time, temperature, and concentration dependent. The pH optimum of internalization of ricin is about pH 7. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis has revealed that intact ricin molecules are internalized. Neither reduction nor proteolytic processing of ricin is required for the entry of ricin into Chinese hamster ovary cells.
The domestic and foreign status of terahertz wireless communication is introduced, and the paper analyzes the feasibility of ultra high speed short range and high speed long range inter-satellite terahertz communication.The capacity of inter-satellite terahertz communication system under the ideal additive white Gaussian noise (AWGN) channel is studied.It simulates the inter-satellite terahertz communication link and calculates high gain antenna design parameter requirements by analyzing more than 100Gbps capacity of short range inter-satellite communication and more than 2.5Gbps capacity of long range inter-satellite communication.
An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.
An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.
Depletion of intracellular K+ has been reported to result in an arrest of the formation of coated pits in human fibroblasts (Larkin, J.M., M.S. Brown, J.L. Goldstein, and R.G.W. Anderson, 1983, Cell, 33:273-285). We have studied the effects of K+ depletion on the cytotoxicities of ricin, Pseudomonas exotoxin A, and diphtheria toxin in Chinese hamster ovary (CHO) cells. The cytotoxicities of ricin and Pseudomonas toxin were enhanced in K+-depleted CHO cells whereas the cytotoxicity of diphtheria toxin was reduced by K+ depletion. The effects of NH4Cl on the cytotoxicities of ricin, Pseudomonas toxin, and diphtheria toxin were found to be similar to those of K+ depletion, and there were no additive or synergistic effects on ricin cytotoxicity by NH4Cl in K+-depleted medium. The enhancement of ricin cytotoxicity by K+ depletion could be completely reversed by the addition of K+, Rb+, and partially by the addition of Cs+, before the ricin treatment, whereas Li+ was ineffective. These protective effects of K+ or Rb+ requires a functional Na+/K+ ATPase. CHO cells grown in K+-depleted media were found to contain 6.3-fold increase in intracellular Na+ level, concomitant with a 10-fold reduction in intracellular K+ level. The enhanced cytotoxicity of ricin in K+-free medium and the increased uptake of Na+ could be abolished by amiloride or amiloride analogues, which are known to be potent inhibitors of the Na+/H+ antiport system. Our results suggest that a depletion of intracellular K+ results in an influx of Na+, which is accompanied by the extrusion of H+. Consequently, there is an alkalinization of the cytosol and the ricin-containing endosomes. As a result, ricin is more efficiently released from the endosomes in-K+-depleted cells. Results from the studies of the binding, internalization, and degradation of 125I-ricin, and the kinetics of inhibition of protein synthesis by ricin in K+-depleted cells are consistent with this working hypothesis.
Combining the current development of high-gain antenna technology, the inter-satellite terahertz communication system's demand for acquisition pointing and tracking (Acquisition Pointing Tracking, APT) technology are analyzed based on the inter-satellite terahertz communication application. The tracking-pointing error has a major influence on the received power of the communication system by simulating and calculating the tracking-pointing error of APT subsystem. The higher the terahertz wave frequency, the greater influence of the tracking-pointing error. The influence of the vibration of the satellite platform on the terahertz communication are analyzed by simulation calculation. There is almost no influence on the terahertz communication when the frequency is 0.34THz, while the influence becomes larger when the frequency increases to 1.5 THz and above. The signal-to-noise ratio of the system changes periodically with the vibration of the satellite platform. This research provides the basis for the design of beam tracing and platform vibration controller of space terahertz communication system.
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