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排序方式: 共有394条查询结果,搜索用时 15 毫秒
1.
One antigen, one gold? A quantitative analysis of immunogold labeling of plasma membrane 5'-nucleotidase in frozen thin sections 总被引:3,自引:0,他引:3
K E Howell U Reuter-Carlson E Devaney J P Luzio S D Fuller 《European journal of cell biology》1987,44(2):318-327
We present an evaluation of the efficiency of immunogold labeling for a low abundance plasma membrane protein. Several independent methods were used to determine the density of 5'-nucleotidase on the plasma membrane of the Fao cell. These methods include morphometry in combination with either enzymology or cell surface radiometric assay. Immunocytochemistry of frozen thin sections with either single or double layers of antibody and visualized with protein A complexed with 5 nm colloidal gold was used to estimate the same density. The application of a balance sheet to immunogold labeling demonstrates that the labeling is never quantitative. For example, labeling of the cell surface is always greater than labeling on the section. We show that departures from the "one antigen, one gold" ideal are systematic, so that an efficiency can be calculated and quantitative results can be obtained. The ability to obtain reliable quantitative results from immunogold labeling extends the utility of this already powerful technique. 相似文献
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Secreted proteome profiling in human RPE cell cultures derived from donors with age related macular degeneration and age matched healthy donors 总被引:1,自引:0,他引:1
An E Lu X Flippin J Devaney JM Halligan B Hoffman EP Hoffman E Strunnikova N Csaky K Hathout Y 《Journal of proteome research》2006,5(10):2599-2610
Age-related macular degeneration (AMD) is characterized by progressive loss of central vision, which is attributed to abnormal accumulation of macular deposits called "drusen" at the interface between the basal surface of the retinal pigment epithelium (RPE) and Bruch's membrane. In the most severe cases, drusen deposits are accompanied by the growth of new blood vessels that breach the RPE layer and invade photoreceptors. In this study, we hypothesized that RPE secreted proteins are responsible for drusen formation and choroidal neovascularization. We used stable isotope labeling by amino acids in cell culture (SILAC) in combination with LC-MS/MS analysis and ZoomQuant quantification to assess differential protein secretion by RPE cell cultures prepared from human autopsy eyes of AMD donors (diagnosed by histological examinations of the macula and genotyped for the Y402H-complement factor H variant) and age-matched healthy control donors. In general, RPE cells were found to secrete a variety of extracellular matrix proteins, complement factors, and protease inhibitors that have been reported to be major constituents of drusen (hallmark deposits in AMD). Interestingly, RPE cells from AMD donors secreted 2 to 3-fold more galectin 3 binding protein, fibronectin, clusterin, matrix metalloproteinase-2 and pigment epithelium derived factor than RPE cells from age-matched healthy donors. Conversely, secreted protein acidic and rich in cysteine (SPARC) was found to be down regulated by 2-fold in AMD RPE cells versus healthy RPE cells. Ingenuity pathway analysis grouped these differentially secreted proteins into two groups; those involved in tissue development and angiogenesis and those involved in complement regulation and protein aggregation such as clusterin. Overall, these data strongly suggest that RPE cells are involved in the biogenesis of drusen and the pathology of AMD. 相似文献
4.
Clustering with neural networks 总被引:3,自引:0,他引:3
Behzad Kamgar-Parsi J. A. Gualtieri J. E. Devaney Behrooz Kamgar-Parsi 《Biological cybernetics》1990,63(3):201-208
Partitioning a set ofN patterns in ad-dimensional metric space intoK clusters — in a way that those in a given cluster are more similar to each other than the rest — is a problem of interest in many fields, such as, image analysis, taxonomy, astrophysics, etc. As there are approximatelyK
N/K! possible ways of partitioning the patterns amongK clusters, finding the best solution is beyond exhaustive search whenN is large. We show that this problem, in spite of its exponential complexity, can be formulated as an optimization problem for which very good, but not necessarily optimal, solutions can be found by using a Hopfield model of neural networks. To obtain a very good solution, the network must start from many randomly selected initial states. The network is simulated on the MPP, a 128 × 128 SIMD array machine, where we use the massive parallelism not only in solving the differential equations that govern the evolution of the network, but also in starting the network from many initial states at once thus obtaining many solutions in one run. We achieve speedups of two to three orders of magnitude over serial implementations and the promise through Analog VLSI implementations of further speedups of three to six orders of magnitude.Supported by a National Research Council-NASA Research Associatship 相似文献
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S. Walsh C.J. Haddad M.A. Kostek T.J. Angelopoulos P.M. Clarkson P.M. Gordon N.M. Moyna P.S. Visich R.F. Zoeller R.L. Seip S. Bilbie P.D. Thompson J. Devaney H. Gordish-Dressman E.P. Hoffman Thomas B. Price L.S. Pescatello 《Gene》2012
Purpose
We investigated the influence of Leptin (LEP) and leptin receptor (LEPR) SNPs on habitual physical activity (PA) and body composition response to a unilateral, upper body resistance training (RT) program.Methods
European-derived American volunteers (men = 111, women = 131, 23.4 ± 5.4 yr, 24.4 ± 4.6 kg·m− 2) were genotyped for LEP 19 G>A (rs2167270), and LEPR 326 A>G (rs1137100), 668 A>G (rs1137101), 3057 G>A (rs1805096), and 1968 G>C (rs8179183). They completed the Paffenbarger PA Questionnaire. Arm muscle and subcutaneous fat volumes were measured before and after 12 wk of supervised RT with MRI. Multivariate and repeated measures ANCOVA tested differences among phenotypes by genotype and gender with age and body mass index as covariates.Results
Adults with the LEP 19 GG genotype reported more kcal/wk in vigorous intensity PA (1273.3 ± 176.8, p = 0.017) and sports/recreation (1922.8 ± 226.0, p < 0.04) than A allele carriers (718.0 ± 147.2, 1328.6 ± 188.2, respectively). Those with the LEP 19 GG genotype spent more h/wk in light intensity PA (39.7 ± 1.6) than A allele carriers (35.0 ± 1.4, p = 0.03). In response to RT, adults with the LEPR 668 G allele gained greater arm muscle volume (67,687.05 ± 3186.7 vs. 52,321.87 ± 5125.05 mm3, p = 0.01) and subcutaneous fat volume (10,599.89 ± 3683.57 vs. − 5224.73 ± 5923.98 mm3, p = 0.02) than adults with the LEPR 668 AA genotype, respectively.Conclusion
LEP19 G>A and LEPR 668 A>G associated with habitual PA and the body composition response to RT. These LEP and LEPR SNPs are located in coding exons likely influencing LEP and LEPR function. Further investigation is needed to confirm our findings and establish mechanisms for LEP and LEPR genotype and PA and body composition associations we observed. 相似文献7.
Claudia T Guimaraes Christiano C Simoes Maria Marta Pastina Lyza G Maron Jurandir V Magalhaes Renato CC Vasconcellos Lauro JM Guimaraes Ubiraci GP Lana Carlos FS Tinoco Roberto W Noda Silvia N Jardim-Belicuas Leon V Kochian Vera MC Alves Sidney N Parentoni 《BMC genomics》2014,15(1)
Background
Aluminum (Al) toxicity is an important limitation to food security in tropical and subtropical regions. High Al saturation on acid soils limits root development, reducing water and nutrient uptake. In addition to naturally occurring acid soils, agricultural practices may decrease soil pH, leading to yield losses due to Al toxicity. Elucidating the genetic and molecular mechanisms underlying maize Al tolerance is expected to accelerate the development of Al-tolerant cultivars.Results
Five genomic regions were significantly associated with Al tolerance, using 54,455 SNP markers in a recombinant inbred line population derived from Cateto Al237. Candidate genes co-localized with Al tolerance QTLs were further investigated. Near-isogenic lines (NILs) developed for ZmMATE2 were as Al-sensitive as the recurrent line, indicating that this candidate gene was not responsible for the Al tolerance QTL on chromosome 5, qALT5. However, ZmNrat1, a maize homolog to OsNrat1, which encodes an Al3+ specific transporter previously implicated in rice Al tolerance, was mapped at ~40 Mbp from qALT5. We demonstrate for the first time that ZmNrat1 is preferentially expressed in maize root tips and is up-regulated by Al, similarly to OsNrat1 in rice, suggesting a role of this gene in maize Al tolerance. The strongest-effect QTL was mapped on chromosome 6 (qALT6), within a 0.5 Mbp region where three copies of the Al tolerance gene, ZmMATE1, were found in tandem configuration. qALT6 was shown to increase Al tolerance in maize; the qALT6-NILs carrying three copies of ZmMATE1 exhibited a two-fold increase in Al tolerance, and higher expression of ZmMATE1 compared to the Al sensitive recurrent parent. Interestingly, a new source of Al tolerance via ZmMATE1 was identified in a Brazilian elite line that showed high expression of ZmMATE1 but carries a single copy of ZmMATE1.Conclusions
High ZmMATE1 expression, controlled either by three copies of the target gene or by an unknown molecular mechanism, is responsible for Al tolerance mediated by qALT6. As Al tolerant alleles at qALT6 are rare in maize, marker-assisted introgression of this QTL is an important strategy to improve maize adaptation to acid soils worldwide.Electronic supplementary material
The online version of this article (doi:10.1186/1471-2164-15-153) contains supplementary material, which is available to authorized users. 相似文献8.
There is a need for safe medications that can effectively support recovery by treating symptoms of protracted abstinence that may precipitate relapse in alcoholics, e.g. craving and disturbances in sleep and mood. This proof-of-concept study reports on the effectiveness of gabapentin 1200 mg for attenuating these symptoms in a non-treatment-seeking sample of cue-reactive, alcohol-dependent individuals. Subjects were 33 paid volunteers with current Diagnostic and Statistical Manual of Mental Disorders-IV alcohol dependence and a strength of craving rating 1 SD or greater for alcohol than water cues. Subjects were randomly assigned to gabapentin or placebo for 1 week and then participated in a within-subjects trial where each was exposed to standardized sets of pleasant, neutral and unpleasant visual stimuli followed by alcohol or water cues. Gabapentin was associated with significantly greater reductions than placebo on several measures of subjective craving for alcohol as well as for affectively evoked craving. Gabapentin was also associated with significant improvement on several measures of sleep quality. Side effects were minimal, and gabapentin effects were not found to resemble any major classes of abused drugs. Results suggest that gabapentin may be effective for treating the protracted abstinence phase in alcohol dependence and that a randomized clinical trial would be an appropriate next step. The study also suggests the value of cue-reactivity studies as proof-of-concept screens for potential antirelapse drugs. 相似文献
9.
Richard B Sherley Robert JM Crawford Bruce M Dyer Jessica Kemper Azwianewi B Makhado Makhudu Masotla 《Ostrich》2019,90(4):335-346
The Cape Gannet Morus capensis is one of several seabird species endemic to the Benguela upwelling ecosystem (BUS) but whose population has recently decreased, leading to an unfavourable IUCN Red List assessment. Application of ‘JARA’ (‘Just Another Red-List Assessment,’ a Bayesian state-space tool used for IUCN Red List assessments) to updated information on the areas occupied by Cape Gannets and the nest densities of breeding birds at their six colonies, suggested that the species should be classified as Vulnerable. However, the rate of decrease of Cape Gannets in their most-recent generation exceeded that of the previous generation, primarily as a result of large decreases at Bird Island, Lambert’s Bay, and Malgas Island, off South Africa’s west coast (the western part of their range). Since the 1960s, there has been an ongoing redistribution of the species from northwest to southeast around southern Africa, and ~70% of the population now occurs on the south coast of South Africa, at Bird Island in Algoa Bay, on the eastern border of the BUS. Recruitment rather than adult survival may be limiting the present population; however, information on the seabird’s demographic parameters and mortality in fisheries is lacking for colonies in the northern part of the BUS. Presently, major threats to Cape Gannet include: substantially decreased availability of their preferred prey in the west; heavy mortalities of eggs, chicks and fledglings at and around colonies, inflicted by Cape Fur Seals Arctocephalus pusillus and other seabirds; substantial disturbance at colonies caused by Cape Fur Seals attacking adult gannets ashore; oiling; and disease. 相似文献
10.
The signal produced by fluorescence in situ hybridization (FISH) often is inconsistent among cells and sensitivity is low. Small DNA targets on the chromatin are difficult to detect. We report here an improved nick translation procedure for Texas red and Alexa Fluor 488 direct labeling of FISH probes. Brighter probes can be obtained by adding excess DNA polymerase I. Using such probes, a 30 kb yeast transgene, and the rp1, rp3 and zein multigene clusters were clearly detected. 相似文献