排序方式: 共有13条查询结果,搜索用时 31 毫秒
1.
Kateryna Raykova Melina V. Jones Hwa Huang Paul F. Hoffman Michael Levy 《Journal of visualized experiments : JoVE》2015,(99)
The rat optic nerve is a useful model for stem cell regeneration research. Direct injection into the rat optic nerve allows delivery into the central nervous system in a minimally-invasive surgery without bone removal. This technique describes an approach to visualization and direct injection of the optic nerve following minor fascial dissection from the orbital ridge, using a conjunctival traction suture to gently pull the eye down and out. Representative examples of an injected optic nerve show successful injection of dyed beads. 相似文献
2.
Victoria Dorovska-Taran Diana Raykova Sava Tishkov Blagoy Blagoev 《Bioorganic chemistry》1980,9(4):482-490
The temperature dependence of the hydrolysis of p-nitrophenyl carboxylates with general formula H(CH2)nCOOC6H4NO2 catalyzed by alkaline mesentericopeptidase has been studied (n varying from 1 to 7, temperature range 2–30°C, pH 8.80, 5 vol% dimethylsulfoxide). The activation parameters of the deacylation step depend on the length of the hydrophobic side chain of the substrate molecule (
,
, and
decrease by 2.0 kcal/mol, 4.9 kcal/mol, and 10 eu, respectively, as the length of the acyl carbon chain increases from n = 1 to n = 4). The following criteria were applied to establish a chemical enthalpy-entropy compensation effect: (a) Exner's plot of log
vs
: (b) Petersen's plot of log, k/T vs 1/T; (c) Exner's statistical treatment in coordinates log k vs 1/T; (d) according to Krug et al. (ΔH≠ vs ΔGThm≠). By use of all the above-mentioned criteria the existence of a chemical enthalpy-entropy compensation effect was proved with an isokinetic temperature β of about 470°K, which is significantly higher than the average experimental temperature. 相似文献
3.
Kinetic Investigation and Anticoagulant Activity of Amide Analogues of Isoform 2 and 3 of Antistasin
Dancho Danalev Dessislava Marinkova Raya Raykova Lyubov Yotova Iren Tsibranska Konstantin Savov Galina Obretenova 《International journal of peptide research and therapeutics》2014,20(2):195-200
The process of blood coagulation is protecting organism from blood loss in case of surface injuries, and is ensuring blood circulation without formation of thrombus. The abnormal functioning of haemostasis is resulting in a many diseases in the recent years. Several serine proteinases and their inhibitors have a very important role in the process of the blood coagulation and are a strong potential alternative for the prevention and treatment of such illnesses. Herein, we report on anticoagulant activity, according to APTT of newly synthesized amide analogues of isoforms 2 and 3 of antistasin. Our study reveals that the replacement of carboxyl with amide function in a C-terminus of peptides is leading to significant increase of the anticoagulant activity. Additionally, some kinetic investigations on the same analogues are done. Our results show that both free acids and amides shortened analogues have a mixed type of inhibition related to serine proteinases from the blood coagulation cascade. The calculated Ki values for the model and the investigated serine proteinases show some selectivity of analogue Phe-Ile-Arg-Pro-Lys-Arg-NH2. The obtained kinetic data correlates with the anticoagulant activity of the newly synthesized analogues. 相似文献
4.
F C Van der Wiele W Atsma B Roelofsen M van Linde J Van Binsbergen F Radvanyi D Raykova A J Slotboom G H De Haas 《Biochemistry》1988,27(5):1688-1694
Long-chain lecithins present in bilayer structures like vesicles or membranes are only very poor substrates for pancreatic phospholipases A2. This is probably due to the fact that pancreatic phospholipases A2 cannot penetrate into the densely packed bilayer structures. To improve the weak penetrating properties of pancreatic phospholipases A2, we prepared and characterized a number of pancreatic phospholipase A2 mutants that have various long acyl chains linked covalently to Lys116 in porcine and to Lys10 in bovine phospholipase A2 [Van der Wiele, F.C., Atsma, W., Dijkman, R., Schreurs, A.M.M., Slotboom, A.J., & De Haas, G.H. (1988) Biochemistry (preceding paper in this issue)]. When monomolecular surface layers of L- and D-didecanoyllecithin were used, it was found that the introduction of caprinic, lauric, palmitic, and oleic acid at Lys116 in the porcine enzyme increases its penetrating power from 13 to about 17, 20, 32, and 22 dyn/cm, respectively, before long lag periods were obtained. Incorporation of a palmitoyl moiety at Lys10 in the bovine enzyme shifted the penetrating power from 11 to about 25 dyn/cm. Only the best penetrating mutant, viz., porcine phospholipase A2 having a palmitoyl moiety at Lys116, was able to cause complete leakage of 6-carboxyfluorescein entrapped in small unilamellar vesicles of egg lecithin under nonhydrolytic conditions. Similarly, only this latter palmitoylphospholipase A2 completely hydrolyzed all lecithin in the outer monolayer of the human erythrocyte at a rate much faster than Naja naja phospholipase A2, the most powerful penetrating snake venom enzyme presently known. 相似文献
5.
Olga Antsiferova Anne Müller Patrick C. R?mer Obinna Chijioke Bithi Chatterjee Ana Raykova Raquel Planas Mireia Sospedra Anatoliy Shumilov Ming-Han Tsai Henri-Jacques Delecluse Christian Münz 《PLoS pathogens》2014,10(8)
Epstein Barr virus (EBV) infection expands CD8+ T cells specific for lytic antigens to high frequencies during symptomatic primary infection, and maintains these at significant numbers during persistence. Despite this, the protective function of these lytic EBV antigen-specific cytotoxic CD8+ T cells remains unclear. Here we demonstrate that lytic EBV replication does not significantly contribute to virus-induced B cell proliferation in vitro and in vivo in a mouse model with reconstituted human immune system components (huNSG mice). However, we report a trend to reduction of EBV-induced lymphoproliferation outside of lymphoid organs upon diminished lytic replication. Moreover, we could demonstrate that CD8+ T cells against the lytic EBV antigen BMLF1 can eliminate lytically replicating EBV-transformed B cells from lymphoblastoid cell lines (LCLs) and in vivo, thereby transiently controlling high viremia after adoptive transfer into EBV infected huNSG mice. These findings suggest a protective function for lytic EBV antigen-specific CD8+ T cells against EBV infection and against virus-associated tumors in extra-lymphoid organs. These specificities should be explored for EBV-specific vaccine development. 相似文献
6.
PRODECOMP (projection decomposition) is an implementation of a multi-way decomposition algorithm for the analysis of two-dimensional projections of high-dimensional nuclear magnetic resonance spectra. The newest version, PRODECOMPv3, features a dramatic speedup, more reliable decompositions, a substantial reduction in memory demands, a new graphical user interface and integration into third-party software. These improvements extend the applicability of decompositions to novel types of NMR data on proteins, yielding backbone and side-chain assignments as well as structural information, and therewith enabling complete characterizations of proteins. AVAILABILITY: Program, short manual and an example calculation are freely available at www2.chem.gu.se/bcbp/nmr/prodecomp.html. 相似文献
7.
Nicole Caduff Donal McHugh Anita Murer Patrick Rmer Ana Raykova Vanessa Landtwing Lisa Rieble Christian W. Keller Michael Prummer Laurent Hoffmann Janice K. P. Lam Alan K. S. Chiang Friedrich Raulf Tarik Azzi Christoph Berger Tina Rubic-Schneider Elisabetta Traggiai Jan D. Lünemann Michael Kammüller Christian Münz 《PLoS pathogens》2020,16(12)
8.
Assignment of protein NMR spectra based on projections,multi-way decomposition and a fast correlation approach 总被引:1,自引:1,他引:0
We present an approach for the assignment of protein NMR resonances that combines established and new concepts: (a) Based on published reduced dimensionality methods, two 5-dimensional experiments are proposed. (b) Multi-way decomposition (PRODECOMP) applied simultaneously to all acquired NMR spectra provides the assignment of resonance frequencies under conditions of very low signal-to-noise. (c) Each resulting component characterizes all spin (1/2) nuclei in a (doubly-labeled) CbetaH(n)-CalphaH-C'-NH-CalphaH-CbetaH(n) fragment in an unambiguous manner, such that sequentially neighboring components have about four atoms in common. (d) A new routine (SHABBA) determines correlations for all component pairs based on the common nuclei; high correlation values yield sequential chains of a dozen or more components. (e) The potentially error-prone peak picking is delayed to the last step, where it helps to place the component chains within the protein sequence, and thus to achieve the final backbone assignment. The approach was validated by achieving complete backbone resonance assignments for ubiquitin. 相似文献
9.
10.
Iglika Mihaylova Vesselina Parvanova Chanita Velikova Galia Kurteva Doroteya Ivanova 《Reports of Practical Oncology and Radiotherapy》2011,16(6):237-242