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61.
Purushottam?D. Dixit 《Biophysical journal》2013,105(12):2743-2750
Dendritic spines are the primary postsynaptic sites of excitatory neurotransmission in the brain. They exhibit a remarkable morphological variety, ranging from thin protrusions, to stubby shapes, to bulbous mushroom shapes. The remodeling of spines is thought to regulate the strength of the synaptic connection, which depends vitally on the number and the spatial distribution of AMPA-type glutamate receptors (AMPARs). We present numerical and analytical analyses demonstrating that this shape strongly affects AMPAR diffusion. We report a pronounced suppression of the receptor exit rate out of spines with decreasing neck radius. Thus, mushroomlike spines become highly effective at retaining receptors in the spine head. Moreover, we show that the postsynaptic density further enhances receptor trapping, particularly in mushroomlike spines local exocytosis in the spine head, in contrast to release at the base, provides rapid and specific regulatory control of AMPAR concentration at synapses. 相似文献
62.
Rakesh Santhanam Xiaoying Rong Ying Huang Barbara A. Andrews Juan A. Asenjo Michael Goodfellow 《Antonie van Leeuwenhoek》2013,103(2):367-373
A Streptomyces strain isolated from a hyper-arid Atacama Desert soil was characterised using a polyphasic taxonomic approach. The strain, designated C2T, had chemical and morphological properties typical of the genus Streptomyces. The isolate formed a branch in the Streptomyces 16S rRNA gene tree together with the type strain of Streptomyces chromofuscus and was also loosely related to Streptomyces fragilis NRRL 2424T. DNA:DNA relatedness values between the isolate and its two phylogenetic neighbours showed that it formed a distinct genomic species. The strain was readily distinguished from these organisms using a combination of morphological and phenotypic data. Based on the genotypic and phenotypic results, isolate C2T represents a novel species in the genus Streptomyces, for which the name Streptomyces bullii sp. nov. is proposed. The type strain is C2T (=CGMCC 4.7019T = KACC 15426T). 相似文献
63.
Manasi Mishra Rakesh S. Joshi Sushama Gaikwad Vidya S. Gupta Ashok P. Giri 《Biochemical and biophysical research communications》2013,430(3):1060-1065
Pin-II protease inhibitors (PIs) are the focus of research interest because of their large structural–functional diversity and relevance in plant defense. Two representative Capsicum annuum PI genes (CanPI-15 and -7) comprising one and four inhibitory repeat domains, respectively, were expressed and recombinant proteins were characterized. β-Sheet and unordered structure was found predominant in CanPI-15 while -7 also displayed the signatures of polyproline fold, as revealed by circular dichroism studies. Inhibition kinetics against bovine trypsin indicated three times higher potency of CanPI-7 (Ki ~ 57 μM) than -15 (~184 μM). Activity and structural stability of these CanPIs were revealed under various conditions of pH, temperature and denaturing agent. Structure prediction, docking studies with proteases and mass spectroscopy revealed the organization of multiple reactive site loops of multi domain PIs in space as well as the steric hindrances imposed while binding to proteases due to their close proximity. 相似文献
64.
Spores of Ganoderma applanatum were collected by gravity. The spore extract was prepared and its biochemical and immunological properties were examined. In isoelectric focusing, the extract had 10–12 bands with pl values between 3.5 to 6.0, the strongest being at 3.5, 3.75, 4.55 and 5.2. In crossedradioimmunoelectrophoresis using human atopic sera, the extract had two dominant and two minor allergens. In IgE immunoblots of sodium dodecylsulphate polyacrylamide gel electrophoresis, the extract showed reactivity at 82, 45, 33, 26, 16, 11 kDa MW, the strongest being at 45 kDa MW. These results indicate that G. applanatum contains a complex mixture of allergens. 相似文献
65.
Astrid Goubet Antoine Chardon Pawan Kumar Pawan K. Sharma Rakesh N. Veedu 《Bioorganic & medicinal chemistry letters》2013,23(3):761-763
C5-Ethynylbenzenesulfonamide-modified nucleotide (EBNA) was investigated as substrate of various DNA polymerases. The experiments revealed that KOD, Phusion and Klenow DNA polymerases successfully accepted EBNA-T nucleotide as a substrate and yielded the fully extended DNA. KOD DNA polymerase was found to be the most efficient enzyme to furnish EBNA-T containing DNA in good yields. Phusion DNA polymerase efficiently amplified the template containing EBNA-T nucleotides by PCR. 相似文献
66.
Imran Ahmad Jay Prakash Thakur Debabrata Chanda Dharmendra Saikia Feroz Khan Shivani Dixit Amit Kumar Rituraj Konwar Arvind Singh Negi Atul Gupta 《Bioorganic & medicinal chemistry letters》2013,23(5):1322-1325
Lipophilic chalcones and their conformationally restricted analogues were synthesized and evaluated for their antitubercular efficacy against Mycobacterium tuberculosis H37Rv strain. Compounds 16, 24, 25a and 25c were found to be active MIC at 60, 30, 3.5 and 7.5 μg-mL?1. In vitro cytotoxicity of compounds 16, 24, 25a, 25c and 26 in non-cancerous human epithelial kidney cell line (HEK-293) showed that most active compound 25a was approximately 2.85 times selective towards tubercular versus healthy cells whereas compound 24 was found to be 16 times selective. 相似文献
67.
Prasoon Gupta Upasana Sharma Praveen Gupta Kiran Babu Siripurapu Rakesh Maurya 《Bioorganic & medicinal chemistry》2013,21(5):1116-1122
Phytochemical investigation of the n-butanol fraction of Evolvulus alsinoides (Linn.) led to the isolation of three new phenolic glycosides, evolvosides C, D and E (1–3) along with six known compounds (4–9). The structures of the compounds were elucidated on the basis of spectroscopic analysis, viz. 1D and 2D NMR experiments, chemical study, and comparison with literature data. Evolvoside C (1) was characterized as kaempferol 4′-O-β-d-glucopyranosyl-(1→2)-α-l-rhamnopyranosyl-(1→6)-β-d-glucopyranoside, whereas evolvosides D and E (2–3) were found to be mono and di-O-methyl derivatives of 1. The new compounds (1–3) represent rare triglycoside derivatives of flavonol at C-4′. The isolated compounds (1–6) were screened for acute stress-induced biochemical changes in male Sprague–Dawley rats at a dose of 40 mg/kg body weight. Compounds 1 and 2 displayed anti-stress effects by normalizing hyperglycemia, plasma corticosterone, plasma creatine kinase, and adrenal hypertrophy. Compounds 3 and 6 were also found to be effective in normalizing most of these stress parameters, whereas compounds 4 and 5 were ineffective in normalizing most of these effects. 相似文献
68.
Total phenolics, flavonoids and antioxidant activity of Saptarangi (Salacia chinensis L.) fruit pulp
J. J. Chavan U. B. Jagtap N. B. Gaikwad G. B. Dixit V. A. Bapat 《Journal of plant biochemistry and biotechnology.》2013,22(4):409-413
Salacia chinensis L. has various beneficial properties including antidiabetic and antioxidant activity. The S. chinensis fruit pulp (SCFP) was extracted with four different solvents (Methanol, ethanol, acetone and water) and was screened for total phenolic content (TPC), total flavonoid content (TFC) and antioxidant activity (AOA). The AOA was assessed by evaluating the 1, 1-diphenyl-2-picrylhydrazyl (DPPH), ferric reducing antioxidant power (FRAP) and metal chelating assay. Methanolic SCFP extract exhibited the highest phenolic content (3.20?±?0.12 mg GAE/g FW) whereas, ethanolic extract showed highest flavonoid content (0.31?±?0.68 mg RE/g FW). The methanolic extract possesses highest antioxidant activity towards DPPH (92.44 %), FRAP (1.939 O.D) and metal chelating activity (74.16 %). AOA (DPPH and FRAP) was significantly correlated with TPC. The results indicated that SCFP is a good natural source of antioxidant compounds for use in food and pharmaceutical industry. 相似文献
69.
The molecular integrity of the active site of phytases from fungi is critical for maintaining phytase function as efficient catalytic
machines. In this study, the molecular dynamics (MD) of two monomers of phytase B from Aspergillus niger, the disulfide intact
monomer (NAP) and a monomer with broken disulfide bonds (RAP), were simulated to explore the conformational basis of the
loss of catalytic activity when disulfide bonds are broken. The simulations indicated that the overall secondary and tertiary
structures of the two monomers were nearly identical but differed in some crucial secondary–structural elements in the vicinity of
the disulfide bonds and catalytic site. Disulfide bonds stabilize the β-sheet that contains residue Arg66 of the active site and
destabilize the α-helix that contains the catalytic residue Asp319. This stabilization and destabilization lead to changes in the shape
of the active–site pocket. Functionally important hydrogen bonds and atomic fluctuations in the catalytic pocket change during the
RAP simulation. None of the disulfide bonds are in or near the catalytic pocket but are most likely essential for maintaining the
native conformation of the catalytic site.
Abbreviations
PhyB - 2.5 pH acid phophatese from Aspergillus niger, NAP - disulphide intact monomer of Phytase B, RAP - disulphide reduced monomer of Phytase B, Rg - radius of gyration, RMSD - root mean square deviation, MD - molecular dynamics. 相似文献70.
Momordica charantia is a well known medicinal plant used in the traditional medicinal system for the treatment of various diseases
including diabetes mellitus. Recently, a novel protein termed as ADMc1 from the seed extract of M. charantia has been identified
and isolated showing significant antihyperglycemic activity in type 1 diabetic rats in which diabetes was induced. However, the
structure of this protein has not yet been analyzed. Homology modeling approach was used to generate a high quality protein 3D
structure for the amino acid sequence of the ADMc1 protein in this study. The comparative assessment of secondary structures
revealed ADMc1 as an all-alpha helix protein with random coils. Tertiary structure predicted on the template structure of Napin of
B. Napus (PDB ID: 1SM7) with which the ADMc1 showed significant sequence similarity, was validated using protein structure
validation tools like PROCHECK, WHAT_CHECK, VERIFY3D and ProSA. Arrangement of disulfide bridges formed by cysteine
residues were predicted by the Dianna 1.1 server. The presence of multiple disulfide bond confers the stable nature of the ADMc1
protein. Further, the biological activity of the ADMc1 was assessed in non-obese diabetic (NOD) mice which are spontaneous
model of type 1 diabetes. Significant reduction in the blood glucose levels of NOD mice was observed up to 8 h post administration
of the rADMc1 protein. Overall, the structural characterizations with antihyperglycemic activity of this seed protein of Momordica
charantia demonstrate its potential as an antidiabetic agent. 相似文献