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91.
Beinat C Banister SD van Prehn S Doddareddy MR Hibbs D Sako M Chebib M Tran T Al-Muhtasib N Xiao Y Kassiou M 《Bioorganic & medicinal chemistry letters》2012,22(7):2380-2384
A series of ligands based on SEN12333, containing either contracted or elongated alkyl chains, were synthesized and evaluated in molecular docking studies against a homology model of the α7 nicotinic acetylcholine receptor (nAChR) subtype. The predicted binding of all ligands was highly similar, with the exception of the analog containing a 5 methylene unit spacer. However, in vitro competition binding assays revealed that the ligands possessed dissimilar binding affinities, with a K(i) range of more than an order of magnitude (K(i)=0.50 to >10 μM), and only SEN12333 itself exhibited functional activity at the α7 nAChR. 相似文献
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93.
While numerous biologically active peptides contain D-amino acids, the elaboration of such species is not carried out by ribosomal synthesis. In fact, the bacterial ribosome discriminates strongly against the incorporation of D-amino acids from D-aminoacyl-tRNAs. To permit the incorporation of D-amino acids into proteins using in vitro protein-synthesizing systems, a strategy has been developed to prepare modified ribosomes containing alterations within the peptidyltransferase center and helix 89 of 23S rRNA. S-30 preparations derived from colonies shown to contain ribosomes with altered 23S rRNAs were found to exhibit enhanced tolerance for D-amino acids and to permit the elaboration of proteins containing D-amino acids at predetermined sites. Five specific amino acids in Escherichia coli dihydrofolate reductase and Photinus pyralis luciferase were replaced with D-phenylalanine and D-methionine, and the specific activities of the resulting enzymes were determined. 相似文献
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Propolis, a resinous substance collected by Apis mellifera bees from various plant sources and mixed with secreted beeswax, is a multifunctional material used by bees in the construction, maintenance, and protection of their hives. The collected propolis sample, from High Egypt, was dark-green with olive-odor. The minimal inhibition concentration (MIC) of propolis-ethanolic-extract, against Aeromonas hydrophila, was 80 μg Propolis-ethanolic-extract and crude propolis (1%) were added to artificial basal diet with (30% crude protein) to evaluate their efficacy on the fish growth-performance, immunostimulation and resistance to A. hydrophila. Two hundred and twenty-five Oreochromis niloticus (8 ± 0.45 g/fish) were divided into three equal treatments (T) of triplet replicates. The fish of T1 were fed on basal diet (control). The fish of T2 were given the basal diet, containing propolis-ethanolic-extract. The fish of T3 were given the basal diet containing crude propolis for 28 day. The fish were intraperitoneally challenged by A. hydrophila (0.2 × 107 cells ml−1) at the end of the feeding period and kept for 15 more days.The best growth rate and feed conversion ratio were obtained with T2. The increase in the average daily gain, specific growth rate and feed efficiency ratio were highly significances in T2 followed by T3 when compared with the control group. The HCT-level and monocyte-counts were increased (T2). No significant change, in the large lymphocytic-count was found among the three treatments (28–27–28%), while the neutrophil-count was significantly decreased (7%) with T2 and increased (13.11%) with the control. A significant increase in serum lysozyme and serum bactericidal activities was found with T2. The RLP against A. hydrophila was high with T2 and T3.The propolis-ethanolic-extract enhanced the growth, immunity and resistance of O. niloticus against A. hydrophila more than the crude propolis. 相似文献
96.
Ben Nejma Mouna Mastouri Maha Bel Hadj Jrad Besma Makhlouf Mohamed Nour Mohamed 《Annals of microbiology》2009,59(4):823-826
Community-acquired methicillin-resistantStaphylococcus aureus (CA-MRSA) strains, known as a nosocomial pathogen, have emerged in the community worldwide. CA-MRSA infects frequently young children and is implicated in skin and soft tissue infections. In the present study, we reported the isolation of CA-MRSA strains from elderly patients admitted to the dermatology department at University Hospital of Monastir. The relatedness of these isolates was investigated by PFGE typing which indicated that all strains were clonally related. MRSA strains were thoroughly characterized by molecular methods which revealed that all isolates possessed the unique sequence type ST80 as well as a single spa type t044. Whole genotypic results suggest that all isolates were PVL producing CA-MRSA and were closely related and belonging to the ST80 clone. 相似文献
97.
Azza Gramoun Tetsuya Goto Tommy Nordström Ori D. Rotstein Sergio Grinstein Johan N.M. Heersche Morris F. Manolson 《Journal of cellular biochemistry》2010,111(2):350-361
Osteoclasts are signaled by the bone matrix proteins fibronectin (FN), vitronectin (VN), and osteopontin (OPN) via integrins. To perform their resorptive function, osteoclasts cycle between compact (polarized), spread (non‐resorbing) and migratory morphologies. Here we investigate the effects of matrix proteins on osteoclast morphology and how those effects are mediated using RAW 264.7 cells differentiated into osteoclasts on FN, VN, and OPN‐coated culture dishes. After 96 h, 80% of osteoclasts on FN were compact while 25% and 16% on VN were in compact and migratory states respectively. In contrast, OPN induced osteoclast spreading. Furthermore, osteoclasts formed on VN and FN were two‐ to fourfold smaller than those formed on OPN in the 21–30 nuclei/osteoclast group. These effects were not due to defects in cytoskeletal reorganization of osteoclasts on VN and FN, demonstrated by the ability of these cells to spread in response to 35 ng/ml macrophage colony stimulating factor (M‐CSF). Conversely, osteoclasts on OPN failed to spread when induced by M‐CSF. Moreover, the extracellular pH on FN and VN (7.25 and 7.3, respectively) was significantly lower than that on OPN (~7.4). We further investigated the role of extracellular pH and found that at pH 7.5 the duration of an osteoclast's compact phase was 25.6 min and that of the spread phase was 62.5 min. Reducing the pH to 7.0 increased the frequency of osteoclast cycling by threefold. These results show that matrix proteins play a role in regulating osteoclast morphology, possibly via altering extracellular and intracellular pH. J. Cell. Biochem. 111: 350–361, 2010. © 2010 Wiley‐Liss, Inc. 相似文献
98.
Khaled A. Khaled Hatem A. Sarhan Mohamed Abbas Ibrahim Azza H. Ali Youssef W. Naguib 《AAPS PharmSciTech》2010,11(2):859-869
This study aimed at preparation of a sustained-release steroidal treatment for chronic inflammatory conditions, such as rheumatoid
arthritis. To achieve such a goal, biodegradable poly-lactide-co-glycolide prednisolone-loaded microspheres were prepared
using o/w emulsion solvent evaporation method. Formulation parameters were adjusted so as to optimize the microsphere characteristics.
The prepared microspheres exhibited smooth and intact surfaces, with average size range not exceeding 65 μm. The encapsulation
efficiency percent of most microsphere formulations fell within the range of 25–68%. Drug release from these microspheres
took place over 4 weeks, with near-to-zero-order patterns. Two successful formulations were chosen for the treatment of unilateral
arthritis, induced in mice using Freund's complete adjuvant (FCA). Inflammatory signs of adjuvant arthritis included severe
swelling of the FCA-injected limbs, in addition to many histopathological lesions. These included inflammatory cell infiltration,
synovial hyperplasia, cartilage, and bone erosion. Parenteral administration of the selected formulae dramatically reduced
the swelling of the FCA-injected limbs. In addition, histological examination revealed that the microsphere treatment protocol
efficiently protected cartilages and bones of mice, injected with FCA initial and booster doses, from erosion. These results
could not be achieved by a single prednisolone dose of 5 mg/kg. 相似文献
99.
Mansour FA Shereif AA Nour el-Dein MM Abou-Dobara MI Ball AS 《Acta microbiologica Polonica》2003,52(2):159-172
Extracellular xylanase (EC 3.2.1.8) from Streptomyces sp. K37 was purified 33.53 by ultrafiltration and cation exchange chromatography followed by gel filtration chromatography. The optimum pH and temperature for purified xylanase were found to be pH 6.0 and 60 degrees C. The Km and V(max) values of the purified xylanase were 15.4 mg ml(-1) and 0.67 micromole reducing sugar min(-1) ml(-1). High performance liquid chromatography (HPLC) gel filtration of the purified xylanase eluted xylanase activity as a peak corresponding to the molecular weight of about 24.3 kDa while the molecular weight determined by SDS-PAGE was found to be 26.4 kDa. The purified xylanase of Streptomyces sp. K37 was found to be endoxylanase and non arabinose liberating enzyme and was highly glycosylated (73.97%). 相似文献
100.