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991.
Becker L Kulkarni S Tiwari G Micci MA Pasricha PJ 《American journal of physiology. Gastrointestinal and liver physiology》2012,302(9):G958-G965
Enteric neural stem cells (ENSCs) are a population of neural crest-derived multipotent stem cells present in postnatal gut that may play an important role in regeneration of the enteric nervous system. In most studies, these cells have been isolated from the layer of the gut containing the myenteric plexus. However, a recent report demonstrated that neurosphere-like bodies (NLBs) containing ENSCs could be isolated from mucosal biopsy specimens from children, suggesting that ENSCs are present in multiple layers of the gut. The aim of our study was to assess whether NLBs isolated from layers of gut containing either myenteric or submucosal plexus are equivalent. We divided the mouse small intestine into two layers, one containing myenteric plexus and the other submucosal plexus, and assessed for NLB formation. Differences in NLB density, proliferation, apoptosis, neural crest origin, and phenotype were investigated. NLBs isolated from the myenteric plexus layer were present at a higher density and demonstrated greater proliferation, lower apoptosis, and higher expression of nestin, p75, Sox10, and Ret than those from submucosal plexus. Additionally, they contained a higher percentage of neural crest-derived cells (99.4 ± 1.5 vs. 0.7 ± 1.19% of Wnt1-cre:tdTomato cells; P < 0.0001) and produced more neurons and glial cells than those from submucosal plexus. NLBs from the submucosal plexus layer expressed higher CD34 and produced more smooth muscle-like cells. NLBs from the myenteric plexus layer contain more neural crest-derived ENSCs while those from submucosal plexus appear more heterogeneous, likely containing a population of mesenchymal stem cells. 相似文献
992.
993.
Manisha Khatri Santosh Kumar Rai Sameena Alam Anjana Vij Manisha Tiwari 《Bioorganic & medicinal chemistry》2009,17(5):1890-1897
In an attempt to design novel 5-HT1A agonists/partial agonists, based on an arylpiperazine nucleus, a series of N-{4-[4-(aryl)piperazine-1-yl]-phenyl}-amine derivatives were synthesized and biologically tested. The anxiolytic effect of the compounds was investigated employing the Elevated plus Maze (EPM) task. On the basis of in vivo functional test, compound 1c (3 mg/kg) and 4c (3 mg/kg) induced significant increments in open arm entries and time on EPM as compared to Buspirone. The anxiolytic effects of compounds 1c and 4c were effectively antagonized by WAY-100635, a 5-HT1A receptor antagonist (0.5 mg/kg). Furthermore, we have also evaluated the concentration of 5-HT in the brain tissue using HPLC with fluorescent detection. Our result showed that serotonin levels were significantly decreased by ~38% (p < 0.001) and ~32% (p < 0.001) after acute administration of compounds 1c and 4c, respectively. These findings suggest that the anxiolytic like activity of these new arylpiperazines is mediated via 5-HT1A receptors in the brain. 相似文献
994.
Chromosomal responses to heat and heavy metal shocks were studied in the pupal trichogen polytene chromosomes of Lucilia cuprina. Heat shock induced seven distinct puffs on different chromosomes at the following loci: 1C2, 21A1, 21C, 23B, 24B, 42A and
95B3. Arsenate and mercury, two of the most common toxic environmental chemical pollutants also, induced almost the same set
of puffs except 20B2, which appeared to be induced by metals only and 95B3, which was not induced by arsenate. The findings
suggest that a common set of gene loci encoding the heat shock proteins is responsive to these diverse environmental stresses.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
995.
Sandhya P Tiwari Edvin Fuglebakk Siv M Hollup Lars Skj?rven Tristan Cragnolini Svenn H Grindhaug Kidane M Tekle Nathalie Reuter 《BMC bioinformatics》2014,15(1)
Background
Normal mode analysis (NMA) using elastic network models is a reliable and cost-effective computational method to characterise protein flexibility and by extension, their dynamics. Further insight into the dynamics–function relationship can be gained by comparing protein motions between protein homologs and functional classifications. This can be achieved by comparing normal modes obtained from sets of evolutionary related proteins.Results
We have developed an automated tool for comparative NMA of a set of pre-aligned protein structures. The user can submit a sequence alignment in the FASTA format and the corresponding coordinate files in the Protein Data Bank (PDB) format. The computed normalised squared atomic fluctuations and atomic deformation energies of the submitted structures can be easily compared on graphs provided by the web user interface. The web server provides pairwise comparison of the dynamics of all proteins included in the submitted set using two measures: the Root Mean Squared Inner Product and the Bhattacharyya Coefficient. The Comparative Analysis has been implemented on our web server for NMA, WEBnm@, which also provides recently upgraded functionality for NMA of single protein structures. This includes new visualisations of protein motion, visualisation of inter-residue correlations and the analysis of conformational change using the overlap analysis. In addition, programmatic access to WEBnm@ is now available through a SOAP-based web service. Webnm@ is available at http://apps.cbu.uib.no/webnma.Conclusion
WEBnm@ v2.0 is an online tool offering unique capability for comparative NMA on multiple protein structures. Along with a convenient web interface, powerful computing resources, and several methods for mode analyses, WEBnm@ facilitates the assessment of protein flexibility within protein families and superfamilies. These analyses can give a good view of how the structures move and how the flexibility is conserved over the different structures.Electronic supplementary material
The online version of this article (doi:10.1186/s12859-014-0427-6) contains supplementary material, which is available to authorized users. 相似文献996.
997.
Youngjoo Byun Susan R. Vogel Andrew J. Phipps Cecilia Carnrot Staffan Eriksson Rohit Tiwari 《Nucleosides, nucleotides & nucleic acids》2013,32(3):244-260
Nineteen lipophilic thymidine phosphate-mimicking compounds were designed and synthesized as potential inhibitors of thymidine monophosphate kinase of Bacillus anthracis, a Gram-positive bacterium that causes anthrax. These thymidine analogues were substituted at the 5′-postion with sulfonamide-, amide-, (thio)urea-, or triazole groups, which served as lipophilic surrogates for phosphate. Three of the tested compounds produced inhibition of B. anthracis Sterne growth and/or thymidine monophosphate activity. Additional studies will be necessary to elucidate the potential of this type of B. anthracis thymidine monophosphate inhibitors as novel antibiotics in the treatment of anthrax. 相似文献
998.
Kamal N. Tiwari John A. Secrist III John A. Montgomery 《Nucleosides, nucleotides & nucleic acids》2013,32(8):1819-1828
Abstract 1,2,3,5-Tetra-O-acetyl-4-thio-D-riboruranose, prepared from 2,3,5-tri-O-benzyl-D-ribofuranose in four steps, was converted to the corresponding 2-chloroadenine nucleoside (8), which was deoxygenated to obtain 2-chloro-2′-deoxy-4′-thioadenosine (12). This is the first report of a 2′-deoxy-4′-thioribonucleoside of a purine rather than a pyrimidine. These novel nucleosides (8 and 12) were cytotoric to several human tumor cell lines in culture. 相似文献
999.
Mitochondria constitute a major source of reactive oxygen species and have been proposed to integrate the cellular responses to stress. In animals, it was shown that mitochondria can trigger apoptosis from diverse stimuli through the opening of MTP, which allows the release of the apoptosis-inducing factor and translocation of cytochrome c into the cytosol. Here, we analyzed the role of the mitochondria in the generation of oxidative burst and induction of programmed cell death in response to brief or continuous oxidative stress in Arabidopsis cells. Oxidative stress increased mitochondrial electron transport, resulting in amplification of H(2)O(2) production, depletion of ATP, and cell death. The increased generation of H(2)O(2) also caused the opening of the MTP and the release of cytochrome c from mitochondria. The release of cytochrome c and cell death were prevented by a serine/cysteine protease inhibitor, Pefablock. However, addition of inhibitor only partially inhibited the H(2)O(2) amplification and the MTP opening, suggesting that protease activation is a necessary step in the cell death pathway after mitochondrial damage. 相似文献
1000.
Plants have been identified as promising expression systems for commercial production of vaccine antigens. In phase I clinical trials several plant-derived vaccine antigens have been found to be safe and induce sufficiently high immune response. Thus, transgenic plants, including edible plant parts are suggested as excellent alternatives for the production of vaccines and economic scale-up through cultivation. Improved understanding of plant molecular biology and consequent refinement in the genetic engineering techniques have led to designing approaches for high level expression of vaccine antigens in plants. During the last decade, several efficient plant-based expression systems have been examined and more than 100 recombinant proteins including plant-derived vaccine antigens have been expressed in different plant tissues. Estimates suggest that it may become possible to obtain antigen sufficient for vaccinating millions of individuals from one acre crop by expressing the antigen in seeds of an edible legume, like peanut or soybean. In the near future, a plethora of protein products, developed through ‘naturalized bioreactors’ may reach market. Efforts for further improvements in these technologies need to be directed mainly towards validation and applicability of plant-based standardized mucosal and edible vaccines, regulatory pharmacology, formulations and the development of commercially viable GLP protocols. This article reviews the current status of developments in the area of use of plants for the development of vaccine antigens. 相似文献