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排序方式: 共有419条查询结果,搜索用时 15 毫秒
41.
Emily Mutzke Emily Chomyshyn Kathy C. Nguyen Maria Blahoianu Azam F. Tayabali 《Analytical biochemistry》2015
Flow cytometry was evaluated for its capacity to detect and distinguish a wide size range (20–2000 nm) of fluorescent polystyrene particles (PSPs). Side scatter and fluorescence parameters could predict dispersed PSP sizes down to 200 nm, but the forward scatter parameter was not discriminatory. Confocal microscopy of flow-sorted fractions confirmed that dispersed PSPs appeared as a single sharp peak on fluorescence histograms, whereas agglomerated PSPs were detected as smaller adjacent peaks. Particles as small as 200 nm could also be detected by flow cytometry after they were first phagocytized by J774A.1 murine macrophages. Confocal microscopy demonstrated that these PSPs were internalized within the cytoplasm. MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] and calcein–AM (acetoxymethyl ester) assays showed that they were not cytotoxic. Internalized PSP size correlated to both cellular side scatter (R2 = 0.9821) and fluorescence intensity (R2 = 0.9993). Furthermore, PSPs of various sizes could be distinguished when J774A.1 cells were loaded with a single size of PSP and mixed with cells containing other sizes. However, spectra of cells loaded with a mixture of PSP sizes resembled those containing only the largest PSP. These data demonstrate the capacity and limitations of phagocytosis-coupled flow cytometry to distinguish between dispersed and agglomerated states and detect a wide size range of particles. 相似文献
42.
Elyse D. Bernard Kathy C. Nguyen Maria C. DeRosa Azam F. Tayabali Rocio Aranda-Rodriguez 《Analytical biochemistry》2015
A multiplexing bead-based platform provides an approach for the development of assays targeting specific analytes for biomonitoring and biosensing applications. Multi-Analyte Profiling (xMAP) assays typically employ a sandwich-type format using antibodies for the capture and detection of analytes of interest, and the system permits the simultaneous quantitation of multiple targets. In this study, an aptamer/antibody assay for the detection of C-reactive protein (CRP) was developed. CRP is an acute phase marker of inflammation whose elevated basal levels are correlated with an increased risk for a number of pathologies. For this assay, an RNA aptamer that binds CRP was conjugated to beads to act as the capture agent. Biotinylated anti-CRP antibody coupled to fluorescently labeled streptavidin was used for quantification of CRP. The detection limit of the CRP assay was 0.4 mg/L in diluted serum. The assay was then used to detect spiked CRP samples in the range of 0.4 to 10 mg/L in diluted serum with acceptable recoveries (extrapolated values of 70–130%), including that of a certified reference material (129% recovery). The successful incorporation of the CRP aptamer into this platform demonstrates that the exploration of other aptamer–target systems could increase the number of analytes measurable using xMAP-type assays. 相似文献
43.
Binyamin R Aslam Khan M Khan AI Azam Khan M Awan FS Khan NA 《Genetics and molecular research : GMR》2011,10(3):1681-1688
Urdbean (Vigna mungo) is an important pulse crop grown worldwide. Urdbean leaf crinkle virus (ULCV) is a pathogen of urdbean found in Pakistan that causes huge losses in yield. Forty urdbean varieties/lines were screened against the virus under field conditions during spring season 2009. None of the lines appeared to be highly resistant or resistant. On the basis of a 0-5 disease rating scale and disease severity index, genotypes varied significantly in their reaction to ULCV. Four lines (M-6206, IAM-382-15, IAM-133, and Mash-1) were moderately resistant, eight were rated as moderately susceptible, and 21 as susceptible; the remaining seven lines were highly susceptible. RAPD analyses revealed an extensive amount of variation, which could be used for cultivar identification. Genetic differentiation among urdbean genotypes was similar to the field screening data. The varieties 6065-3 and 6206 were highly susceptible and moderately resistant, respectively, to ULCV under field conditions, confirmed by the RAPD analysis. These varieties were the most diverse varieties in the similarity matrix (67.2%), while the varieties IAM-382-9 and 07M003 were the most similar (98.4%). This information will help in the recognition of available resistant germplasms that can resist this disease and will be utilized for urdbean improvement in Pakistan. 相似文献
44.
Peripheral blood neutrophil activation patterns are associated with pulmonary inflammatory responses to lipopolysaccharide in humans 总被引:1,自引:0,他引:1
Abraham E Nick JA Azam T Kim SH Mira JP Svetkauskaite D He Q Zamora M Murphy J Park JS Overdier K Dinarello CA 《Journal of immunology (Baltimore, Md. : 1950)》2006,176(12):7753-7760
Increased nuclear accumulation of NF-kappaB in LPS-stimulated peripheral blood neutrophils has been shown to be associated with more severe clinical course in patients with infection associated acute lung injury. Such observations suggest that differences in neutrophil response may contribute to the pulmonary inflammation induced by bacterial infection. To examine this question, we sequentially measured LPS-induced DNA binding of NF-kappaB in neutrophils collected from healthy humans on at least three occasions, each separated by at least 2 wk, and then determined pulmonary inflammatory responses after instillation of LPS into the lungs. Consistent patterns of peripheral blood neutrophil responses, as determined by LPS-induced NF-kappaB DNA binding, were present in volunteers, with a >80-fold difference between individuals in the mean area under the curve for NF-kappaB activation. The number of neutrophils recovered from bronchoalveolar lavage after exposure to pulmonary LPS was significantly correlated with NF-kappaB activation in peripheral blood neutrophils obtained over the pre-LPS exposure period (r = 0.65, p = 0.009). DNA binding of NF-kappaB in pulmonary neutrophils also was associated with the mean NF-kappaB area under the curve for LPS-stimulated peripheral blood neutrophils (r = 0.63, p = 0.01). Bronchoalveolar lavage levels of IL-6 and TNFRII were significantly correlated with peripheral blood neutrophil activation patterns (r = 0.75, p = 0.001 for IL-6; and r = 0.48, p = 0.049 for TNFRII. These results demonstrate that stable patterns in the response of peripheral blood neutrophils to LPS exist in the human population and correlate with inflammatory response following direct exposure to LPS in the lung. 相似文献
45.
Gholivand K Alizadegan AM Firooz AA Khajeh K Naderi-Manesh H Bijanzadeh H 《Journal of enzyme inhibition and medicinal chemistry》2006,21(1):105-111
Carbacylamidophosphates with the general formula RC(O)NHP(O)R1R2 constitute organophosphorus compounds that are used as insecticides, pesticides and ureas inhibitors. In this work, we studied the inhibition potency of CCl3-C(O)NHP(O)Cl21, CHCl2C(O)NHP(O)Cl(2)2, CH2ClC(O)NHP(O)Cl23 and CF3C(O)NHP(O)Cl(2)4, which are the major intermediates for carbacylamidophosphates synthesis towards human erythrocyte acetylcholinesterase (hAChe) activity using Ellman's modified kinetic method. Unexpectedly, it was observed that they were not only hydrolytically unstable but also inhibited hAChE in a similar manner to that produced by organophosphorus insecticides. Enzymatic data, bimolecular inhibition rate constants (ki) and IC50 values for inhibition of hAChE demonstrated that they are irreversible inhibitors and the inhibition potency of compound 2 (IC50 = 88 microM) was the greatest in comparison with compounds 1, 3 and 4. Also the electropositivity of the phosphorus atom and the hydrophobicity of the compounds demonstrated that these two factors play an additional effect and different role in the inhibitory activity of these compounds. Hydrolytic stability of the compounds was determined by 31P NMR monitoring of the loss of the parent molecules with D2O as a function of time. This study considers antiacetylcholinesterase activity according to the structural and the electronic aspects of compounds 1-4, according to IR, 1H, 13C and 31P NMR spectral data. 相似文献
46.
Molecular Characterization of Mercury Resistant Bacteria Inhabiting Polluted Water Bodies of Different Geographical Locations in India 总被引:1,自引:0,他引:1
Mercury pollution is a major environmental problem that arises as a result of natural processes as well as from anthropogenic sources. In response to toxic mercury compounds, microbes have developed astonishing array of resistance systems to detoxify them. To address this challenge, this study was aimed in screening bacterial isolates for their tolerance against varied concentrations of phenylmercuric acetate. Mercury transformation by bacteria being sensitive to factors such as available carbon source, etc. that affect mer-mediated transformation, screened mercury tolerant bacteria were also studied for their tolerance to different antimicrobials and carbon sources, followed by identification using biochemical as well as 16S rRNA approach. Following identification, gene encoding organomercurial lyase catalyzing protonolytic cleavage of C-Hg bond of organic mercury was amplified using gene specific primers, cloned in pGEMT(?) easy vector and sequenced. Microbe-based approach using organomercurial lyase encoded by merB gene being potentially economic, provides foundation to facilitate genetic manipulation of this environmentally important enzyme to remove high concentrations of obstinate mercury using holistic, multifaceted approach for use in bioremediation through generation of transgenics or as catalyst for use in bioreactors. 相似文献
47.
Plastid structure and carotenogenic gene expression in red- and white-fleshed loquat (Eriobotrya japonica) fruits 总被引:1,自引:0,他引:1
Fu X Kong W Peng G Zhou J Azam M Xu C Grierson D Chen K 《Journal of experimental botany》2012,63(1):341-354
Loquat (Eriobotrya japonica Lindl.) can be sorted into red- and white-fleshed cultivars. The flesh of Luoyangqing (LYQ, red-fleshed) appears red-orange because of a high content of carotenoids while the flesh of Baisha (BS, white-fleshed) appears ivory white due to a lack of carotenoid accumulation. The carotenoid content in the peel and flesh of LYQ was approximately 68 μg g(-1) and 13 μg g(-1) fresh weight (FW), respectively, and for BS 19 μg g(-1) and 0.27 μg g(-1) FW. The mRNA levels of 15 carotenogenesis-related genes were analysed during fruit development and ripening. After the breaker stage (S4), the mRNA levels of phytoene synthase 1 (PSY1) and chromoplast-specific lycopene β-cyclase (CYCB) were higher in the peel, and CYCB and β-carotene hydroxylase (BCH) mRNAs were higher in the flesh of LYQ, compared with BS. Plastid morphogenesis during fruit ripening was also studied. The ultrastructure of plastids in the peel of BS changed less than in LYQ during fruit development. Two different chromoplast shapes were observed in the cells of LYQ peel and flesh at the fully ripe stage. Carotenoids were incorporated in the globules in chromoplasts of LYQ and BS peel but were in a crystalline form in the chromoplasts of LYQ flesh. However, no chromoplast structure was found in the cells of fully ripe BS fruit flesh. The mRNA level of plastid lipid-associated protein (PAP) in the peel and flesh of LYQ was over five times higher than in BS peel and flesh. In conclusion, the lower carotenoid content in BS fruit was associated with the lower mRNA levels of PSY1, CYCB, and BCH; however, the failure to develop normal chromoplasts in BS flesh is the most convincing explanation for the lack of carotenoid accumulation. The expression of PAP was well correlated with chromoplast numbers and carotenoid accumulation, suggesting its possible role in chromoplast biogenesis or interconversion of loquat fruit. 相似文献
48.
J. Neurochem. (2012) 122, 1137-1144. ABSTRACT: The α9α10 nicotinic acetylcholine receptor (nAChR) may be a potential target in pathophysiology of the auditory system, chronic pain, and breast and lung cancers. Alpha-conotoxins, from the predatory marine snail Conus, are potent nicotinic antagonists, some of which are selective for the α9α10 nAChR. Here, we report a two order of magnitude species difference in the potency of α-conotoxin RgIA for the rat versus human α9α10 nAChR. We investigated the molecular mechanism of this difference. Heterologous expression of the rat α9 with the human α10 subunit in Xenopus oocytes resulted in a receptor that was blocked by RgIA with potency similar to that of the rat α9α10 nAChR. Conversely, expression of the human α9 with that of the rat α10 subunit resulted in a receptor that was blocked by RgIA with potency approaching that of the human α9α10 receptor. Systematic substitution of residues found in the human α9 subunit into the homologous position in the rat α9 subunit revealed that a single point mutation, Thr56 to Ile56, primarily accounts for this species difference. Remarkably, although the α9 nAChR subunit has previously been reported to provide the principal (+) binding face for binding of RgIA, Thr56 is located in the (-) complementary binding face. 相似文献
49.
Saedi TA Moeini H Tan WS Yusoff K Daud HM Chu KB Tan SG Bhassu S 《Molecular biology reports》2012,39(5):5785-5790
White tail disease (WTD) is a serious viral disease in the hatcheries and nursery ponds of Macrobrachium rosenbergii in many parts of the world. A new disease similar to WTD was observed in larvae and post larvae of M. rosenbergii cultured in Malaysia. In the present study, RT-PCR assay was used to detect the causative agents of WTD, M. rosenbergii nodavirus (MrNV) and extra small virus (XSV) using specific primers for MrNV RNA2 and XSV. The results showed the presence of MrNV in the samples with or without signs of WTD. However, XSV was only detected in some of the MrNV-positive samples. Phylogenetic analysis showed that the RNA2 of our Malaysian isolates were significantly different from
the other isolates. Histopathological studies revealed myofiber degeneration of the tail muscles and liquefactive myopathy
in the infected prawns. This was the first report on the occurrence of MrNV in the Malaysian freshwater prawn. 相似文献
50.
Attar AM Kharkhaneh A Etemadifar M Keyhanian K Davoudi V Saadatnia M 《Biological trace element research》2012,146(2):150-153
Exposure to heavy metals has been associated to a higher incidence of multiple sclerosis. In this work, we present a possible
relationship between serum mercury levels and development of multiple sclerosis in Isfahan, the third largest city in Iran.
Seventy-four patients affected by multiple sclerosis were retrieved from multiple sclerosis (MS) clinic in Isfahan, Iran.
By matching sex and age, 74 healthy volunteers were chosen as control group. Blood samples were collected and serum mercury
content was determined. Serum mercury level in MS patients was significantly higher than controls (9.6 ± 10.17 vs. 5.7 ± 8.6,
P = 0.037). Concerning all MS patients, serum mercury value was significantly higher than the mercury concentration founded
in control subjects {odd ratio: 2.39 (CI, 1.96–2.94), P = 0.00}. Serum mercury level is higher in MS patients with odd ratio equal to 2.39 compared with healthy individuals. It
may reveal that high mercury levels in serum might help MS development in susceptible individuals. More studies with larger
sample size are needed to confirm this hypothesis. 相似文献