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1.
A dipstick enzyme immunoassay for the rapid detection of Fusarium T-2 toxin in wheat was developed. An Immunodyne ABC membrane was precoated with rabbit anti-mouse immunoglobulins. After the strips were immersed in a solution of monoclonal anti-T-2 toxin antibodies, a direct competitive enzyme immunoassay was performed. This assay included the incubation of the antibody-coated dipsticks in a mixture of sample and T-2 toxin-horseradish peroxidase conjugate. Afterwards, the strips were placed in a chromogen-containing substrate solution (H202-3,3',5,5'-tetramethylbenzidine) for color reaction. The dot color intensity of toxin-positive dipsticks was visually distinguishable from that of the negative control. A portable colorimeter was used to confirm and quantify the visual observations. With coated strips, the tests could be performed in 45 min. The visual detection limit for T-2 toxin in buffer solution was 0.25 ng/ml. Artificially infected wheat samples were extracted with 80% methanol-water. A dilution of the raw extract of 1:8 was sufficient to avoid matrix effects. It was possible to make visually a clear distinction between the negative control and a wheat extract spiked with 12 ng/g. 相似文献
2.
The Drosophila melanogaster gene flightless-I, involved in gastrulation and
muscle degeneration, has Caenorhabditis elegans and human homologues. In
these highly conserved genes, two previously known gene families have been
brought together, families encoding the actin- binding proteins related to
gelsolin and the leucine-rich-repeat (LRR) group of proteins involved in
protein-protein interactions. Both these gene families exhibit
characteristics of molecular changes involving replication slippage and
exon shuffling. Phylogenetic analyses of 19 amino acid sequences of 6
related protein types indicate that actin- associated proteins related to
gelsolin are monophyletic to a common ancestor and include flightless
proteins. Conversely, comparison of 24 amino acid sequences of LRR proteins
including the flightless proteins indicates that flightless proteins are
members of a structurally related subgroup. Included in the flightless
cluster are human and mouse rsp-1 proteins involved in suppressing v-Ras
transformation of cells and the membrane-associated yeast (Saccharomyces
cerevisae) adenylate cyclase whose analogous LRRs are required for
interaction with Ras proteins. There is a strong possibility that ligands
for this group could be related and that flightless may have a similar role
in Ras signal transduction. It is hypothesized that an ancestral monomeric
gelsolin precursor protein has undergone at least four independent gene
reorganization events to account for the structural diversity of the extant
family of gelsolin-related proteins and that gene duplication and exon
shuffling events occurred prior to or at the beginning of multicellular
life, resulting in the evolution of some members of the family soon after
the appearance of actin-type proteins.
相似文献
3.
Magnesium-induced inner membrane aggregation in heart mitochondria: prevention and reversal by carboxyatractyloside and bongkrekic acid 下载免费PDF全文
Mg(2+) at an optimal concentration of 2mM (ph 6.5) induces large increases (up to 30 percent) in the optical density of bovine heart mitochondria incubated under conditions of low ionic strength (< approx. 0.01). The increases are associated with aggregation (sticking together) of the inner membranes and are little affected by changes in the energy status of the mitochondria. Virtually all of a number of other polyvalent cations tested and Ag(+) induce increases in mitochondrial optical density similar to those induced by Mg(2+), their approximate order of concentration effectiveness in respect to Mg(2+) being: La(3+) > Pb(2+) = Cu(2+) > Cd(2+) > Zn(2+) > Ag(+) > Mn(2+) > Ca(2+) > Mg(2+). With the exception of Mg(2+), all of these cations appear to induce swelling of the mitochondria concomitant with inner membrane aggregation. The inhibitors of the adenine nucleotide transport reaction carboxyatratyloside and bongkrekic acid are capable of preventing and reversing Mg(2+)-induced aggregation at the same low concentration required for complete inhibition of phosphorylating respiration, suggesting that they inhibit the aggregation by binding to the adenine nucleotide carrier. The findings are interpreted to indicate (a) that the inner mitochondrial membrane is normally prevented from aggregating by virtue of its net negative outer surface change, (b) that the cations induce the membrane to aggregate by binding at its outer surface, decreasing the net negative charge, and (c) that carboxyatractyloside and bongkrekic acid inhibit the aggregation by binding to the outer surface of the membrane, increasing the net negative charge. 相似文献
4.
An electrocatalytic glucose sensor for in vivo application has been developed. The principle of measurement is based on the direct electrochemical oxidation of glucose at a platinum electrode without an enzymatic reaction. In an in vivo experiment with sheep the glucose sensor was tested with respect to its cross-sensitivity towards ascorbic acid, paracetamol and sulfanilamide. The influence of these substances could be reduced by an adapted calibration to such an extent, that the sensor performance could be ensured. 相似文献
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6.
Model F Osborn N Ahlquist D Gruetzmann R Molnar B Sipos F Galamb O Pilarsky C Saeger HD Tulassay Z Hale K Mooney S Lograsso J Adorjan P Lesche R Dessauer A Kleiber J Porstmann B Sledziewski A Lofton-Day C 《Molecular cancer research : MCR》2007,5(2):153-163
Aberrant DNA methylation occurs early in oncogenesis, is stable, and can be assayed in tissues and body fluids. Therefore, genes with aberrant methylation can provide clues for understanding tumor pathways and are attractive candidates for detection of early neoplastic events. Identification of sequences that optimally discriminate cancer from other diseased and healthy tissues is needed to advance both approaches. Using well-characterized specimens, genome-wide methylation techniques were used to identify candidate markers specific for colorectal neoplasia. To further validate 30 of these candidates from genome-wide analysis and 13 literature-derived genes, including genes involved in cancer and others with unknown functions, a high-throughput methylation-specific oligonucleotide microarray was used. The arrays were probed with bisulfite-converted DNA from 89 colorectal adenocarcinomas, 55 colorectal polyps, 31 inflammatory bowel disease, 115 extracolonic cancers, and 67 healthy tissues. The 20 most discriminating markers were highly methylated in colorectal neoplasia (area under the receiver operating characteristic curve > 0.8; P < 0.0001). Normal epithelium and extracolonic cancers revealed significantly lower methylation. Real-time PCR assays developed for 11 markers were tested on an independent set of 149 samples from colorectal adenocarcinomas, other diseases, and healthy tissues. Microarray results could be reproduced for 10 of 11 marker assays, including eight of the most discriminating markers (area under the receiver operating characteristic curve > 0.72; P < 0.009). The markers with high specificity for colorectal cancer have potential as blood-based screening markers whereas markers that are specific for multiple cancers could potentially be used as prognostic indicators, as biomarkers for therapeutic response monitoring or other diagnostic applications, compelling further investigation into their use in clinical testing and overall roles in tumorigenesis. 相似文献
7.
Rates and patterns of evolution in partial sequences of five mitochondrial
genes (cytochrome b, ATPase 6, NADH dehydrogenase subunit 5, tRNA(Glu), and
the control region) were compared among taxa in the passerine bird genera
Fringilla and Carduelis. Rates of divergence do not vary significantly
among genes, even in comparisons with the control region. Rate variation
among lineages is significant only for the control region and NADH
dehydrogenase subunit 5, and patterns of variation are consistent with the
expectations of neutral theory. Base composition is biased in all genes but
is stationary among lineages, and there is evidence for directional
mutation pressure only in the control region. Despite these similarities,
patterns of substitution differ among genes, consistent with alternative
regimes of selective constraint. Rates of nonsynonymous substitution are
higher in NADH dehydrogenase subunit 5 than in other protein-coding genes,
and transitions exist in elevated proportions relative to transversions.
Transitions appear to accumulate linearly with time in tRNA(Glu), and
despite exhibiting the highest overall rate of divergence among species,
there are no transversional changes in this gene. Finally, for resolving
phylogenetic relationships among Fringilla taxa, the combined
protein-coding data are broadly similar to those of the control region in
terms of phylogenetic informativeness and statistical support.
相似文献
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T Akerström J Crona A Delgado Verdugo LF Starker K Cupisti HS Willenberg WT Knoefel W Saeger A Feller J Ip P Soon M Anlauf PF Alesina KW Schmid M Decaussin P Levillain B Wängberg JL Peix B Robinson J Zedenius M Bäckdahl S Caramuta KA Iwen J Botling P Stålberg JL Kraimps H Dralle P Hellman S Sidhu G Westin H Lehnert MK Walz G Akerström T Carling M Choi RP Lifton P Björklund 《PloS one》2012,7(7):e41926