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排序方式: 共有203条查询结果,搜索用时 31 毫秒
31.
Anshika Tandon Munesh Kumar Harioudh Nayab Ishrat Amit Kumar Tripathi Saurabh Srivastava Jimut Kanti Ghosh 《Cellular and molecular life sciences : CMLS》2018,75(13):2431-2446
MD2, a 160-residue accessory glycoprotein, is responsible for the recognition and binding of Gram-negative bacterial membrane component, lipopolysaccharide (LPS). Internalization of pathogen inside the mononuclear phagocytes has also been attributed to MD2 which leads to the clearance of pathogens from the host. However, not much is known about the segments in MD2 that are responsible for LPS interaction or internalization of pathogen inside the defense cells. A 16-residue stretch (MD54) from MD2 protein has been identified that possesses a short heptad repeat sequence and four cationic residues enabling it to participate in both hydrophobic and electrostatic interactions with LPS. An MD54 analog of the same size was also designed in which a leucine residue at a heptadic position was replaced with an alanine residue. MD54 but not its analog, MMD54 induced aggregation of LPS and aided in its internalization within THP-1 monocytes. Furthermore, MD54 inhibited LPS-induced nuclear translocation of NF-κB in PMA-treated THP-1 and TLR4/MD2/CD14-transfected HEK-293T cells and the production of pro-inflammatory cytokines. In addition, in in vivo experiments, MD54 showed marked protection and survival of mice against LPS-induced inflammation and death. Overall, we have identified a short peptide with heptad repeat sequence from MD2 that can cause aggregation of LPS and abet in its internalization within THP-1 cells, resulting in attenuation of LPS-induced pro-inflammatory responses in vitro and in vivo. 相似文献
32.
Summary Triweekly i.m. injections of clomiphene citrate (group 1, 25 g/0.5 ml and group II, 50 g/1.0 ml) were administered for a period of 3 months during the preparatory period to female fresh water teleosts exhibiting ovarian recrudescence, while a control group received 0.5 ml of physiological saline throughout the period of experimentation i.e., from February through April. 50 g clomiphene citrate treatment brought about a steady increase in ovarian size, and oocytes began to enlarge and mature and finally ovulation took place in April. This is 4 months ahead of their normal occurrence.The authors wish to express their gratitude to Richardson Merrel Co. for supplying the sample of clomiphene citrate, and Dr K.N. Udupa, Institute of Medical Sciences, Banaras Hindu University, Varanasi for facilities. 相似文献
33.
R. Kumar 《Cellular and molecular life sciences : CMLS》1980,36(4):411-412
Summary Synthetic analogue of ecdysone, 3, 14-dihydroxy-5-cholest-7-en-6-one did not bring the scorpionPalamnaeus bengalensis to moult. It also failed completely in stimulating the scorption to produce any change related to moulting.Acknowledgment. Author is grateful to Dr Suresh C. Shrivastava for providing research facilities, Dr S.P. Tewarson for encouragement and S.C.S.T. (U.P.) for funds. Present address: Department of Zoology, Lucknow Christian College, Lucknow-226001. 相似文献
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Objective: A natural cyclic peptide previously isolated from Citrus medica was synthesized by coupling of tetrapeptide units Boc-Leu-Pro-Trp-Leu-OMe and Boc-Ile-Ala-Ala-Gly-OMe after proper deprotection at carboxyl and amino terminals followed by cyclization of linear octapeptide segment. Methods: Solution phase technique was adopted for the synthesis of cyclooctapeptide-sarcodactylamide. Required tetrapeptide units were prepared by coupling of Boc-protected dipeptides viz. Boc-Leu-Pro-OH and Boc-Ile-Ala-OH with respective dipeptide methyl esters Trp-Leu-OMe and Ala-Gly-OMe. Cyclization of linear octapeptide unit was done by p-nitrophenyl ester method. The structure of synthesized cyclopolypeptide was elucidated by FTIR, ^1H NMR, ^13C NMR, FABMS spectral data and elemental analysis. The newly synthesized peptide was evaluated for dif- ferent pharmacological activities including antimicrobial, anthelmintic and cytotoxic activities. Results: Synthesis of sarcodactylamide was accomplished with 〉78% yield utilizing dicyclohexylcarbodiimide (DCC) as coupling agent. Newly synthesized peptide possessed potent cytotoxic activity against Dalton's lymphoma ascites (DLA) and Ehrlich's ascites carcinoma (EAC) cell lines, in addition to moderate anthelmintic activity against earthworms Megascoplex konkanensis, Pontoscotex corethruses and Eudrilus sp. Moreover, cyclopolypeptide displayed good antimicrobial activity against pathogenic fungi Candida albicans and Gram-negative bacteria Pseudomonas aeruginosa, in comparison to standard drugs griseofulvin and ciprofloxacin. Conclusion: Solution phase technique employing DCC and triethylamine (TEA) as base proved to be effective for the synthesis of natural cyclooctapeptide. N-methyl morpholine (NMM) was found to be a better base for the cyclization of linear octapeptide unit in comparison to TEA and pyridine. 相似文献
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37.
Strong coupling of a single photon to a superconducting qubit using circuit quantum electrodynamics 总被引:1,自引:0,他引:1
Wallraff A Schuster DI Blais A Frunzio L Huang R Majer J Kumar S Girvin SM Schoelkopf RJ 《Nature》2004,431(7005):162-167
The interaction of matter and light is one of the fundamental processes occurring in nature, and its most elementary form is realized when a single atom interacts with a single photon. Reaching this regime has been a major focus of research in atomic physics and quantum optics for several decades and has generated the field of cavity quantum electrodynamics. Here we perform an experiment in which a superconducting two-level system, playing the role of an artificial atom, is coupled to an on-chip cavity consisting of a superconducting transmission line resonator. We show that the strong coupling regime can be attained in a solid-state system, and we experimentally observe the coherent interaction of a superconducting two-level system with a single microwave photon. The concept of circuit quantum electrodynamics opens many new possibilities for studying the strong interaction of light and matter. This system can also be exploited for quantum information processing and quantum communication and may lead to new approaches for single photon generation and detection. 相似文献
38.
Falkner-Skan方程描述磁场中连续平直面上不可压缩粘性流的边界层流,本文研究此方程初值问题之解的渐近性质。 相似文献
39.
D. N. Kumar 《Cellular and molecular life sciences : CMLS》1978,34(3):397-402
Summary In spectral studies of -irradiated protein-dye complexes, influences of concentrations of the components and changes in dye character are mainly noted.I thank Mr K. L. Bhattacharya, Officer in Charge of this Centre for encouragement, Prof. K. M. Khanna of Birla Institute of Technology, Ranchi, for discussion and the authorities of Chittaranjan Cancer Hospital, Calcutta, for irradiation facilities. 相似文献
40.
D. N. Kumar 《Cellular and molecular life sciences : CMLS》1977,33(8):1041-1042
Summary Effects of -rays on the DNA-cholesterol complex have been studied. Radiation-induced changes are found and compared with those on DNA-dye or drug complexes.Acknowledgment. Thanks are due to P. K. Roy, K. L. Bhattacharya and K. M. Khanna (Department of Physics, Birla Institute of Technology, Ranchi) for helpful discussions and the Chittaranjan Cancer Hospital (Calcutta) for irradiation facilities. 相似文献