Automated measurements of antilisterial activities of lactate and diacetate in ready-to-eat meat

Standard procedures to enumerate Listeria organisms rely on plating food samples on selective agar media. The procedures are labor-intensive, and because of the limited sensitivity, pre-enrichment step is required for the detection of low numbers of the pathogen. In the present study, an automated rapid optic procedure and the standard procedure were used to determine the behavior of the pathogen in ready-to-eat (RTE) meat and to test the effect of antilisterial agents. Listeria monocytogenes strain Scott A or a six-strain mixture of Listeria was studied using lactate (2.5%), diacetate (0.2%) and their combination in beef bologna and in sterile beef emulsion. Samples stored for up to 60 days at 5 and 10 degrees C were tested at time intervals during storage. Using the plate count method, each of the salts caused a delay in growth of the pathogen, and the salt combination was most effective causing listeriostatic effects and decline in growth of the pathogen at 5 degrees C. High negative correlation (r), ranging from 0.92 to 0.99, was obtained between the detection time (DT) recorded by the optic procedure (BioSys instrument) and cell numbers determined by the plate count procedure. The rapid (< 24 h) optic procedure was reliable in assessing the efficacy of antimicrobials and in rapid detection of low levels of listeriae that are undetectable by direct plating procedure.     

In situ measurement of HMG-CoA reductase activity in digitonin-permeabilized hepatocytes

An assay procedure for HMG-CoA reductase is described which allows rapid measurement of the activity of this enzyme in isolated rat hepatocytes. In a one step procedure digitonin permeabilizes the plasma membrane and at the same time HMG-CoA reductase activity is measured. Digitonin at a concentration of 64 micrograms per mg of cell protein was found to be optimal for exposing microsomal HMG-CoA reductase to the assay components. The enzyme assay is linear with time up til 5 min and with protein concentrations in the range of 0.06-0.6 mg of cell protein per assay. It is shown that cellular enzyme activity is affected by preincubation of intact hepatocytes with a variety of short-term modulators of hepatic cholesterogenesis.     

甲醇营养型酵母高密度培养过程中甲醇和乙醇的GC快速检测

采用气相色谱法（GC）快速检测甲醇营养型酵母发酵液中的甲醇、乙醇含量,具有样品处理简便,测定时间较短,结果重视性好的特点。在1－10mg/mL范围内具有很好的线性关系。在毕赤酵母高密度表达发酵过程中应用此法对甲醇和乙醇进行实时监空,细胞终密度超过300g/L（干重）。本方法为甲醇营养型酵母工程菌的发酵中试工艺研究提供了重要 的发酵生化参数。     

A method using solubility to predict dry matter digestibility of cellulosic materials.

A rapid chemical procedure based on the solubility of a holocellulose sample in a system of dimethyl sulfoxide with paraformaldehyde has been developed to provide a laboratory method for predicting dry matter digestibility of cellulose containing samples. The amount of dry matter solubilized by the chemical procedure was closely correlated with anaerobic, in vitro, rumen fluid digestion and with digestibility as measured by aerobic Cellulomonas, sp. bacteria. The quantity of solvent and dissolving time had little effect on solubility over a wide range. The method is rapid, well suited for various cellulosic materials, and may be carried out with simple equipment and facilities.     

转基因植物快速检测方法的研究

本试验对转基因植物检测中的DNA提取和PCR扩增程序作了改进。经试验,本研究建立的DNA快速提取法与目前广泛使用的CTAB法相比更为简便,快速和经济,提取的DNA质量主扩增效果无明显差异,可用于多种转基因植物,多种植物组织的DNA提取,利用复合PCR法可在同一反应管中同步检测35N,NOS及CP4－EPSPS基因,明显提高了检测效率。应用本试验建立的DNA快速提取－复合PCR扩增－银染检测技术可在6小时内得出结果,达到了快速,简便,灵敏,可靠的检测目的。     

乳鼠脑组织中牛磺酸的快速检测

建立一种快速、准确的牛磺酸定量检测方法。采用Beckman公司6300黄金系统氨基酸分析仪,在锂柱130 min程序生理体液分析方法基础上,根据牛磺酸(TAU)的特性,建立了脑组织中TAU快速测定方法。用此方法完成TAU分析的时间为17 min,比原方法缩短了123 min。且有较好的重现性(日内RSD 0.42%,日间RSD 0.57%)、回收率高(98.39%)。本方法简便、快速、准确、可靠,适用于临床和科研工作。     

Evaluation of a rapid method for the quantitative estimation of coliforms in meat by impedimetric procedures.

A 24-h instrumental procedure is described for the quantitative estimation of coliforms in ground meat. The method is simple and rapid, and it requires but a single sample dilution and four replicates. The data are recorded automatically and can be used to estimate coliforms in the range of 100 to 10,000 organisms per g. The procedure is an impedance detection time (IDT) method using a new medium, tested against 131 stock cultures, that markedly enhances the impedance response of gram-negative organisms, and it is selective for coliforms. Seventy samples of ground beef were analyzed for coliforms by the IDT method and the conventional three-dilution, two-step most-probable-number test tube procedure. Seventy-nine percent of the impedimetric estimates fell within the 95% confidence limits of the most-probable-number values. This corresponds to the criteria used to evaluate other coliform tests, with the added advantage of a single dilution and more rapid results.     

Rapid Screening for Cell Surface Binding Monoclonal Antibodies

A procedure is described which allows for rapid detection of cell surface binding or cytoskeleton binding monoclonal antibodies. At the same time this procedure ensures that selected antibodies will be useful in Western blot analysis. This procedure including the cytochemistry and Western blot analysis requires only 100 μl of supernatant and can be done directly from the original 96 well plates into which the fusion was plated. One person can easily assay several hundred supernatants in one day for the ability to stain both cells and selected proteins in Western blot analysis.     

Rapid purification of uricase from Bacillus fastidiosus

Summary A simple, rapid procedure was developed for the purification of uricase from Bacillus fastidiosus. The enzyme was purified to homogeneity in a two-step procedure with the aid of fast-flow column chromatography. In this way high yields (37 %) of pure uricase with a specific activity of 78.3 U/mg were obtained in a short time.     

A Metachromatic Stain for Neural Tissue

The need for rapid histological feedback on neural tissue is ever present. Although there are several stains which can be readily used for staining either cell bodies or fiber tracts, adequate contrasting stains which are both rapid and easy to apply are not generally available. In 1936 Chang presented a technique for whole brains utilizing the metachromatic properties of thionin. Unfortunately this procedure was very time consuming. For the last several years we have worked with several variations of this stain and have found that thionin can be reliably used as a polychrome stain for sections of neural tissue obtained from a freezing microtome.     

A new method for the rapid separation of cell organelles

A rapid procedure is described for the separation of plant cell organelles from castor bean endosperm (Ricinus communis). This method is based on the reorientation of sucrose density gradients during centrifugation in a vertical rotor, thus resulting in a shorter path length and drastically reduced run times. Comparison to a separation by a standard procedure shows that, by using this method, equal resolution is possible in less than 10% spin time.     

Rapid and high-throughput genotyping of Staphylococcus epidermidis isolates by automated multilocus variable-number of tandem repeats: a tool for real-time epidemiology

Fast and reliable genotyping methods allowing real-time epidemiology would be instrumental to discriminate Staphylococcus epidermidis isolates, in order to evaluate potential cross-infections or to follow genome content of infecting strains of this important opportunistic pathogen. We describe an automated multilocus variable-number tandem repeat-based assay (MLVA) for the rapid genotyping of S. epidermidis. Multiplex PCR amplifications using 6 primer pairs targeting gene-regions containing variable numbers of tandem repeats and the mecA gene are resolved by micro-capillary electrophoresis and automatically assessed by cluster analysis. This genotyping technique was evaluated for discriminatory power and reproducibility on 2 sequenced strains, on a collection of 21 strains previously characterized using genotyping reference methods and finally on 65 clinical isolates identified in two different institutions. All steps of this new procedure were developed to ensure rapid turn-around time and moderate costs. Our results suggest that this rapid approach is a valuable epidemiological tool to genotype S. epidermidis isolates in real-time. The rapid analysis of a limited number of evolutionary markers showed a power of discrimination similar to that of pulse-field gel electrophoresis (PFGE) or multilocus sequence type (MLST). This type of rapid and high-throughput methodology opens the possibility to rapidly assess long-term nosocomial transmission or to characterize infecting strains in the general procedure of routine laboratories, in real-time.     

Measurement of diacylglycerol acyltransferase activity in isolated hepatocytes

An assay procedure for diacylglycerol acyltransferase that allows rapid measurement of the activity of this enzyme in isolated hepatocytes is described. The one-step procedure involves permeabilization of the plasma membrane with digitonin and simultaneous measurement of diacylglycerol acyltransferase activity. Digitonin at a concentration of 64 microg/mg of cellular protein was found to be optimal for exposing microsomal diacylglycerol acyltransferase to the components of the assay. The enzyme assay is linear with time up to 4 min and with protein concentrations in the range 0.25-2.4 mg of cellular protein/assay. It is shown that there is a good correlation of cellular enzyme activity as determined in digitonin-permeabilized hepatocytes with the rate of triacylglycerol synthesis in intact hepatocytes.     

A novel rapid and continuous procedure for large-scale purification of magnetosomes from <Emphasis Type="Italic">Magnetospirillum gryphiswaldense</Emphasis>

A new rapid and continuous procedure was developed for purifying magnetosomes from Magnetospirillum gryphiswaldense MSR-1 cells on a large scale. The procedure included these steps: disruption of cells with a high-pressure homogeniser, isolation of magnetosomes with a continuous magnetism isolation system accompanied by low-power ultrasonication and urea treatment, removal of adsorbed and surface proteins with proteinase K, removal of nucleic acids with electro-elution, and replacement of the PBS buffer with distilled water by a magnetically stirred system. The purified magnetosomes were stored at −20 °C after lyophilized and treated with γ-rays. The time required for purification was reduced from 20–30 to 2–5 days. Evaluation of the purity of the resulting magnetosomes was carried out with SDS-PAGE, PCR, and Fourier-transform infrared spectroscopy. The overall data suggest that the method presented here is a simple, rapid, continuous, and highly efficient procedure for large-scale purification of magnetosomes.     

A rapid method for staining large chylomicrons

In this report, we present a rapid method for producing high-quality micrographs suitable for determining the size distributions of particles in concentrated samples of postprandial chylomicrons and chylomicron remnants. The procedure consists of mixing particles with osmium tetroxide in water to stabilize the lipids of the particles. These fixed and positively stained particles are then negatively stained with phosphotungstate in the presence of dilute sucrose. This dual staining procedure prevents the fusion and clustering of chylomicrons during processing for electron microscopy and is effective with particles of different lipid compositions. In addition, this procedure is simple and rapid, adding only one mixing step and 5 min to the preparation time required for conventional negative stains.     

重组人睫状神经营养因子的复性研究

利用凝胶层析对人睫状神经营养因子原核基因工程产品进行复性研究,发现此方法的复性率高于稀释透析法.而且在复性的同时也进行了一步纯化工作.该方法简单、迅速、高效、重复性好,可用于规模生产.     

Development of a new procedure based on the energy charge measurement using ATP bioluminescence assay for the detection of living mould from graphic documents

Fungal contamination is a major cause of deterioration in libraries and archives. Curators and conservators increasingly need rapid microbiological analyses. This paper presents a rapid detection method for the fungal contaminants on documents. A previous study showed that the calculation of energy charge, using bioluminescence ATP assays, provides a useful indicator to determinate the viability of fungal strains. We argue that this sensitive and time‐saving method is better than traditional culture techniques. However, the procedure needs to be modified to make it usable for lay persons. An improved and simplified protocol is proposed here for the extraction of adenylate nucleotides (AN) from fungal spores and for their measurements. Our new procedure can detect the existence of viable fungal strains on documents, presenting suspect spots within minutes. The extraction is performed by filtration with DMSO–TE solution as extractant. The different step of the measurement of AN content is carried out successively in a single test tube instead of the three tubes necessary in the initial method. The new procedure was tested on 12 strains among those most frequently found in archives and libraries and validated on swab samples from real documents. Copyright © 2008 John Wiley & Sons, Ltd.     

一种适于转基因水稻PCR检测的微量DNA快速提取法

对已报道的小麦基因组DNA快速提取方法的部分步骤进行了简化,在水稻上进行了尝试。结果表明,简化法提取的水稻基因组DNA完整性好,PCR扩增效果与试剂盒提取法无明显的差异,结果稳定可靠;而且整个提取过程操作简单、花费时间少,样品用量少,仅需5-10mg,适用于大规模转基因水稻的PCR检测。     

A rapid nonchromatographic assay for aminopropyltransferases

Aminopropyltransferases are key enzymes in the biosynthesis of the polyamines spermidine and spermine. A procedure is described for assaying these enzymes by differential charcoal adsorption of 14C-labeled decarboxylated adenosylmethionine substrate from the labeled polyamine product. This assay is linear with time and enzyme concentration, and is suitable for use with a variety of amine acceptors. This procedure has the advantage, over those previously used, that it is extremely rapid yet very sensitive.     

Rapid enzyme-linked immunosorbent assay (ELISA) for detection of IgG antibodies to Candida albicans

A rapid enzyme-linked immunosorbent assay (ELISA) where the performance time was shortened to 4h was compared with counter-immunoelectrophoresis (CIE) and a standard ELISA procedure for the detection of IgG antibodies to Candida albicans in 61 patients with suspected invasive candidosis. Using a C. albicans cytoplasmic antigen the rapid ELISA compared well with CIE and the standard ELISA. Seventeen sera that reacted with two concentrations of C. albicans antigen in CIE were also positive in both forms of ELISA. Four sera that were CIE-negative were positive in the standard ELISA and three were also positive in the rapid ELISA. The rapid ELISA provides a sensitive and reproducible test for routine serological investigation of different forms of candidosis.