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Isolation Methods (isolation + methods)
Selected AbstractsMycobacterium avium ssp. paratuberculosis: its incidence, heat resistance and detection in milk and dairy productsINTERNATIONAL JOURNAL OF DAIRY TECHNOLOGY, Issue 1 2001Irene R Grant Mycobacterium avium ssp. paratuberculosis (MAP) causes Johne's disease in cattle and other ruminants and has been implicated as a possible cause of Crohn's disease in humans. The organism gains access to raw milk directly through excretion into the milk within the udder, and indirectly through faecal contamination during milking. MAP has been shown to survive commercial pasteurization in naturally infected milk, even at the extended holding time of 25 s. Pasteurized milk must therefore be considered a vehicle of transmission of MAP to humans. Isolation methods for MAP from milk are problematical, chiefly because of the absence of a suitable selective medium. This makes food surveillance programs and research on this topic difficult. The MAP problem can be addressed in two main ways: by devising a milk-processing strategy that ensures the death of the organism; and/or strategies at farm level to prevent access of the organism into raw milk. Much of the research to date has been devoted to determining if a problem exists and, if so, the extent of the problem. Little has been directed at possible solutions. Given the current state of information on this topic and the potential consequences for the dairy industry, research is urgently needed so that a better understanding of the risks and the efficacy of possible processing solutions can be determined. [source] The study of the aroma profile characteristics of durian pulp during storage by the combination sampling method coupled with GC,MSFLAVOUR AND FRAGRANCE JOURNAL, Issue 1 2007Zhuo-Min Zhang Abstract In this study, a combination sampling method, including headspace solid-phase micro-extraction (HSSPME), simultaneous distillation extraction (SDE) and steam distillation (SD), were used to study the aroma profile characteristics of durian (Durio zibethinus Murr.) pulp during storage, followed by gas chromatography,mass spectrometric (GC,MS) detection; 26 and 22 aroma volatiles of fresh and deteriorated durian pulps were identified according to different degrees of certainty. Volatile esters were identified as the main aromatic components of durian pulp. Most ethyl esters reduced in concentration during storage, whereas the methyl, propyl and butyl esters increased. Different aroma profile characteristics at the fresh and deteriorated storage phases obtained by HSSPME were specified by principal component analysis (PCA). Five typical aroma volatiles contributing greatly to the difference of aroma profile characteristics of durian pulp at the fresh and deteriorated storage phases were distilled by common model strategy. These compounds are potential bio-markers for durian degradation, but further study is needed. Tentative results suggest that combining HSSPME with conventional volatile isolation methods would yield more representative data on changes in the aroma of durian pulp during storage. Copyright © 2006 John Wiley & Sons, Ltd. [source] Effects of different brush border membrane vesicle isolation protocols on proteomic analysis of Cry1Ac binding proteins from the midgut of Helicoverpa armigeraINSECT SCIENCE, Issue 6 2008Li-Zhen Chen Abstract Brush border membrane vesicles (BBMV) isolated from insect midguts have been widely used to study Cry1A binding proteins. Sample preparation is important in two-dimensional electrophoresis (2-DE), so to determine a suitable BBMV preparation method in Helicoverpa armigera for 2-DE, we compared three published BBMV preparation methods mostly used in sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). All methods yielded similar types and numbers of binding proteins, but in different quantities. The Abdul-Rauf and Ellar protocol was the best of the three, but had limitations. Sufficient protein quantity is important for research involving limited numbers of insects, such as studies of insect resistance to Bacillus thuringiensis in the field. Consequently, we integrated the three BBMV isolation methods into a single protocol that yielded high quantities of BBMV proteins from H. armigera larval midguts, which proved suitable for 2-DE analysis. [source] Listeria monocytogenes in spontaneous abortions in humans and its detection by multiplex PCRJOURNAL OF APPLIED MICROBIOLOGY, Issue 5 2007S. Kaur Abstract Aim: To assess the extent of Listeria monocytogenes in causation of human spontaneous abortions by isolation methods and PCR analysis for the presence of virulence-associated genes. Methods and Results: A total of 305 samples comprising blood, urine, placental bits, faecal and vaginal swabs were collected from 61 patients with spontaneous abortions. Listeria spp. were isolated from 10 samples collected from nine (14·8%) patients. Confirmation of these isolates was based on biochemical tests, haemolysis on blood agar, CAMP test, phosphatidylinositol-specific phospholipase C (PI-PLC) assay followed by in vivo pathogenicity tests and multiplex PCR to detect virulence-associated genes (prfA, plcA, hlyA, actA and iap). Three isolates were confirmed as L. monocytogenes. Of these, two isolates turned out to be pathogenic and found to posses all five genes. However, the remaining two haemolytic L. monocytogenes isolates lacking the plcA gene and activity in the PI-PLC assay were found to be nonpathogenic by in vivo tests. Conclusions: The occurrence of pathogenic L. monocytogenes in cases of spontaneous abortions was 3·3%. It seems that the plcA gene and its expression have an important role as essential virulence determinants in pathogenic Listeria spp. Significance and Impact of the Study: The recovery of pathogenic L. monocytogenes isolates from cases of spontaneous abortion indicates the significance of listeric infection in pregnant women. [source] Selection of bead-displayed, PNA-encoded chemicalsJOURNAL OF MOLECULAR RECOGNITION, Issue 5 2010Natalie R. Gassman Abstract The lack of efficient identification and isolation methods for specific molecular binders has fundamentally limited drug discovery. Here, we have developed a method to select peptide nucleic acid (PNA) encoded molecules with specific functional properties from combinatorially generated libraries. This method consists of three essential stages: (1) creation of a Lab-on-BeadÔ library, a one-bead, one-sequence library that, in turn, displays a library of candidate molecules, (2) fluorescence microscopy-aided identification of single target-bound beads and the extraction , wet or dry , of these beads and their attached candidate molecules by a micropipette manipulator, and (3) identification of the target-binding candidate molecules via amplification and sequencing. This novel integration of techniques harnesses the sensitivity of DNA detection methods and the multiplexed and miniaturized nature of molecule screening to efficiently select and identify target-binding molecules from large nucleic acid encoded chemical libraries. Beyond its potential to accelerate assays currently used for the discovery of new drug candidates, its simple bead-based design allows for easy screening over a variety of prepared surfaces that can extend this technique's application to the discovery of diagnostic reagents and disease markers. Copyright © 2009 John Wiley & Sons, Ltd. [source] Principal-component analysis of multiscale data for process monitoring and fault diagnosisAICHE JOURNAL, Issue 11 2004Seongkyu Yoon Abstract An approach is presented to multivariate statistical process control (MSPC) for process monitoring and fault diagnosis based on principal-component analysis (PCA) models of multiscale data. Process measurements, representing the cumulative effects of many underlying process phenomena, are decomposed by applying multiresolution analysis (MRA) by wavelet transformations. The decomposed process measurements are rearranged according to their scales, and PCA is applied to these multiscale data to capture process variable correlations occurring at different scales. Choosing an orthonormal mother wavelet allows each principal component to be a function of the process variables at only one scale level. The proposed method is discussed in the context of other multiscale approaches, and illustrated in detail using simulated data from a continuous stirred tank reactor (CSTR) system. A major contribution of the paper is to extend fault isolation methods based on contribution plots to multiscale approaches. In particular, once a fault is detected, the contributions of the variations at each scale to the fault are computed. These scale contributions can be very helpful in isolating faults that occur mainly at a single scale. For those scales having large contributions to the fault, one can further compute the variable contributions to those scales, thereby making fault diagnosis much easier. A comparison study is done through Monte Carlo simulation. The proposed method can enhance fault detection and isolation (FDI) performance when the frequency content of a fault effect is confined to a narrow-frequency band. However, when the fault frequency content is not localized, the multiscale approaches perform very comparably to the standard single-scale approaches, and offer no real advantage. © 2004 American Institute of Chemical Engineers AIChE J, 50: 2891,2903, 2004 [source] Polymorphism and solvatomorphism 2008JOURNAL OF PHARMACEUTICAL SCIENCES, Issue 9 2010Harry G. Brittain Abstract Papers and patents that deal with polymorphism and solvatomorphism have been summarized in an annual review. The review is divided into sections that cover articles of general interest, computational and theoretical studies, preparative and isolation methods, structural characterization and properties of polymorphic and solvatomorphic systems, studies of phase transformations, effects associated with secondary processing, and United States patents issued during 2008. © 2009 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 99:3648,3664, 2010 [source] Sampling flower scent for chromatographic analysisJOURNAL OF SEPARATION SCIENCE, JSS, Issue 11 2008Elena E. Stashenko Abstract The analysis of flower volatiles requires special methods for their isolation with enrichment. Living flowers show a continuous change in their volatile profile that depends on intrinsic (genetic) and external (light, temperature, hydric stress) factors. Excised flowers suffer rapid deterioration and loss of volatiles. While industrial isolation methods for flower volatiles are well established, those at the laboratory-scale experience progressive development, in the search for higher sensitivity, reproducibility, and simplicity. This review covers the flower scent sampling methods most commonly employed during the last decade, and includes comments on their strengths and limitations. The strengths of headspace solid-phase microextraction (HS-SPME) for in vivo monitoring are emphasized with the examples of monitoring the circadian variation of Brugmansia suaveolens flower scent and of volatile aldehyde detection in flower scent using on-fiber derivatization. [source] Improved bioluminescent enzyme immunoassay for the rapid detection of Salmonella in chicken meat samplesLETTERS IN APPLIED MICROBIOLOGY, Issue 5 2005S. Fukuda Abstract Aims:, To evaluate an improved bioluminescent enzyme immunoassay (BEIA) using biotinylated firefly luciferase for the rapid detection of Salmonella in naturally contaminated chicken meat samples. Methods and Results:, Capture agents and lipopolysaccharide (LPS) extraction reagents for Salmonella were investigated to improve the sensitivity of the BEIA. Also, the use of Oxoid SPRINT (Simple Pre-enrichment and Rapid Isolation New Technology) as a pre-enrichment and selective medium for 26-h BEIA detection of Salmonella in chicken meat samples was examined. The use of polymyxin B as a capture agent on solid support and 3-[(3-Cholamidopropyl) dimethylammonio] propanesulfonic acid (CHAPS) for extraction of the LPS facilitated sensitive detection of Salmonella. Of 120 chicken meat samples, 25 samples were positive using the improved BEIA with the SPRINT and 25 samples were positive using the SPRINT followed by the standard isolation methods. Conclusions:, The improved BEIA, in which polymxin B was used as a capture agent and CHAPS was used for extraction of the antigen, had a sensitivity of 96·0% and a specificity of 98·9% for the detection of Salmonella in chicken meat. Significance and Impact of the Study:, The improved BEIA combined with the SPRINT medium for the detection of Salmonella in chicken meat samples produced comparable results to the culture methods in 26 h. [source] The use of biomagnetic separation to recover DNA suitable for PCR from Claviceps species ,LETTERS IN APPLIED MICROBIOLOGY, Issue 2 2000D.L. Scott Jr DNA analysis of agriculturally important fungi using polymerase chain reaction (PCR)-based methods is becoming routine in research and for diagnostic purposes. Rapid, small-scale DNA isolation methods that take advantage of the sensitivity, speed and automation potential of PCR technology are needed for timely analysis of important plant pathogens. DNA isolated from Claviceps africana (causal agent of ergot of sorghum) using several standard DNA extraction protocols was found to be unamplifiable using PCR. The standard methods apparently failed to separate DNA from substances inhibitory to the Taq polymerase enzyme. We obtained DNA amenable to PCR analysis using a novel method involving magnetic beads and high salt extraction buffer. The biomagnetic purification method allowed us to obtain reliable PCR amplification of the internal transcribed spacer (ITS) regions of rDNA of Claviceps africana, making genetic comparisons possible. [source] Use of Volatiles as Indicators of Lipid Oxidation in Muscle FoodsCOMPREHENSIVE REVIEWS IN FOOD SCIENCE AND FOOD SAFETY, Issue 1 2006Carolyn F. Ross ABSTRACT Lipid oxidation has long been recognized as a leading cause of quality deterioration in muscle foods and is often the decisive factor in determining food product storage life. Lipid oxidation generates a number of products, including volatile compounds, which are the major contributors to the development of rancid off-flavors and odors. Over the years, methodologies have been developed to quantify lipid oxidation products in muscle foods. This article reviews the analytical methods that have been used to quantify volatile compounds as indicators of lipid oxidation in muscle foods. The sampling methodologies of distillation/solvent extraction and headspace analysis, and isolation methods associated with gas chromatographic (GC) and high-performance liquid chromatography (HPLC) analyses are discussed. Within gas chromatographic methodologies, headspace (HS) sampling (static HS, dynamic purge-and-trap HS techniques, and solid-phase microextraction [SPME]) are addressed. [source] | |||||||||||||