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ABSTRACT: The detection of cadmium ions using enzyme-linked immunosorbent assays (ELISA) has been reported by several research groups. Because cadmium ions are too small to stimulate the immune system, high molecular weight immunogens of cadmium are constructed using bifunctional chelators. At present, the most commonly used bifunctional chelator for the preparation of antigens for heavy metal ions is 1-(4-isothiocyanobenzyl) ethylenediamine N,N,N',N'-tetraacetic acid (ITCBE). However, the price of ITCBE is high. So we are interested in a cheaper bifunctional chelator, 1-(4-aminobenzyl) ethylenediamine N,N,N',N'-tetraacetic acid (aminobenzyl-EDTA). Here, cadmium ions were conjugated to carrier proteins using aminobenzyl-EDTA to make artificial antigens. Then, several mice were immunized with the antigen. And monoclonal antibodies (MAbs) against cadmium were produced. Spleen cells of immunized mice were fused with myeloma cells. The resulting hybridomas were screened using protein conjugates which were covalently bound to metal-free EDTA or cadmium. Three hybridoma cell lines (A3, E4 and B5) that produced MAbs with high selectivity and sensitivity were expanded for further study. Cross-reactivities with other metals were below 1 %. These antibodies were used to construct competitive ELISAs. The IC(50) for A3 was 8.4 μg/l. The detection range and the lowest detection limit using the antibody A3 was 0.394-64.39 and 0.051 μg/l, respectively. Spike-recovery studies in tap water showed that the antibody A3 could be used for cadmium detection in drinking water.
Biological trace element research 02/2013; · 1.92 Impact Factor
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ABSTRACT: The objective of our study was to evaluate whether feeding pseudopurpurin affects bone mineral density and bone geometry architecture in rats. Pseudopurpurin was extracted, analyzed and purified using an HLPC-ESI-MS. Rats were given 0% and 0.5% pseudopurpurin powder in their diet. Femurs of rats were examined at 0.5, 1 and 2 months after pseudopurpurin feeding. Compared with rats in the group 0%, the bone mineral density, and the calcium, magnesium, zinc and manganese concentrations in the rats femur in the group 0.5% increased significantly at 1 month and 2 months after pseudopurpurin feeding. Analytical results of micro-computed tomography showed that the group 0.5% displayed an increase in the trabecular volume fraction, trabecular thickness and trabecular number of the distal femur at 1 and 2 months after pseudopurpurin feeding, and the mean thickness, inner perimeter, outer perimeter, and area of the femur diaphysis were significantly increased at 2 months after pseudopurpurin feeding compared with the group 0%. In parallel, the trabecular separation and structure model index of the distal femur were decreased, compared with the group 0% at 1 and 2 months after pseudopurpurin feeding. In the 0.5% and 0% groups, there was no damage to kidney and liver by histopathology analysis. The long-term feeding of pseudopurpurin is safe for rats. The feeding of 0.5% pseudopurpurin which has specific chemical affinities for calcium for bone improvement and level of bone mineral density, enhances the geometry architecture compared with the 0% group.
International Journal of Molecular Sciences 01/2012; 13(3):3431-43. · 2.60 Impact Factor
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ABSTRACT: BALB/c mice were immunized four times with formalin-prepared abrin-a. Using the polyethylene glycol method, immunized splenocytes were isolated and fused with SP2/0 cells. An indirect ELISA was established and used to detect positive clones secreting monoclonal antibodies (mAbs) against abrin-a. After analysis, three hybridoma clones secreting IgG-subtype mAbs were obtained. The antibodies were purified from the hybridoma growth medium using protein A or G affinity chromatography. Western blot analysis was used to analyze the antigenic epitopes on abrin-a recognized by the mAbs. The mAbs were specific for abrin-a, with no detectable cross-reactivity with several homologous toxins and associated agglutinins. Sandwich ELISA was then developed using these mAbs, which had a detection limit for abrin-a of 7.8 ng/mL.
Journal of Agricultural and Food Chemistry 09/2011; 59(18):9796-9. · 2.82 Impact Factor
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ABSTRACT: High-affinity anti-abrin-a monoclonal and polyclonal antibodies were used to develop a sandwich immunochromatographic assay and silver enhancement technology was used to further increase the sensitivity. Using a matrix of double distilled water or soybean milk with added abrin-a, the visual detection limit was found to be 10 ng mL(-1). The detection limit was 0.1 ng mL(-1) for abrin-a, an increase in sensitivity of 100-fold when the silver enhancement technology was employed. The assay was portable and very simple to perform and the detection was completed within 20 min without complicated handling procedures. There was no significant cross-reactivity with several homologous toxins and associated agglutinin. The assay reagents could be stored for 12 weeks at 4°C without significant loss of activity. These characteristics make the strip assay to be an ideal candidate for the development of a rapid toxin detection kit.
Biosensors & bioelectronics 02/2011; 26(8):3710-3. · 5.43 Impact Factor
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ABSTRACT: Primary hepatocytes are commonly used during in vitro studies, but care must be taken with isolation and culture of the cells to ensure their viability. In this study, hepatocytes were isolated from the liver (caudate process) of a newborn calf by the collagenase perfusion and digestion method. The trypan blue exclusion method was used to determine total cell number and the survival rate of hepatocytes, while hepatocyte function was assessed by measuring lactate dehydrogenase, albumin and urea in culture medium supernatants at 24, 48, 72, 96, 120, 144 and 168 h. Results showed that the number of viable cells/g of liver (wet weight) averaged 1.12×10(7) cells/g, with an average hepatocyte viability of 85.7% (range 83-92%). After 48 h of culture, the hepatocytes solidly adhered to the well culture plate and were spread in an epithelioid shape, with clear cell boundaries between the cells and biliary ductule-like structures formed which persisted for up to 10 days. Hepatocyte function was optimal at 72 h after isolation and culture. This simple and economical procedure for the isolation and culture of viable cells may be useful for in vitro bovine hepatocyte studies.
The Veterinary Journal 02/2011; 191(3):323-6. · 2.24 Impact Factor
