Search results for "extraction"

A multiplex RTi-PCR reaction for simultaneous detection of Escherichia coli O157:H7, Salmonella spp. and Staphylococcus aureus on fresh, minimally pr…

2007

In this work, a new multiplex single-tube real-time PCR approach is presented for the detection of Escherichia coli O157:H7, Salmonella spp. and Staphylococcus aureus, three of the more frequent food-borne bacterial pathogens that are usually investigated in a variety of food matrices. The study includes the design and specificity testing, of a new primer and probe specific for Salmonella spp. Reaction conditions were adjusted for the simultaneous amplification and detection of specific fragments in the beta-glucuronidase (uidA, E. coli) and Thermonulease (nuc, Sta. aureus) genes, and in the replication origin sequence (oriC, Salmonella spp.). Melting-curve analysis using a SYBR Green I RTi…

PCR-based procedures for detection and quantification of Staphylococcus aureus and their application in food.

2006

Aims:  To evaluate the specificity of nuc targeted primers for PCR detection of Staphylococcus aureus in different food matrices and to establish a RTQ-PCR procedure suitable for the routine detection and quantification of this pathogen in food. Methods and Results:  Specificity of nuc targeted primers (Pri1–Pri2 and the newly designed RTQ-PCR primers) was tested on a total of 157 strains of genetically confirmed identity, including reference and food isolates. PCR detection on artificially inoculated beef samples by DNA extraction using a DNeasy Tissue Kit (Qiagen GmhH, Hilden, Germany) showed a sensitivity value around 103 CFU g−1. The two RTQ-PCR systems, incorporating SYBR-Green I and T…

Comparison of Four Commercial DNA Extraction Kits for PCR Detection of Listeria monocytogenes, Salmonella, Escherichia coli O157:H7, and Staphylococc…

2008

Four commercial DNA extraction methods, PrepMan Ultra (Applied Biosystems), InstaGene Matrix (BioRad), DNeasy Tissue kit (Qiagen), and UltraClean (MoBio), were tested for PCR detection of Listeria monocytogenes, Escherichia coli O157: H7, Salmonella, and Staphylococcus aureus in fresh, minimally processed vegetables. For comparative purposes, sensitivity assays with specific PCRs were carried out after DNA extraction with the four methods in green pepper, broccoli, and onion artificially inoculated with the four pathogens separately. As confirmed by statistical analysis, the DNeasy Tissue kit rendered the highest sensitivity values in the three matrices assayed for Salmonella, L. monocytoge…

Salt drying: a low-cost, simple and efficient method for storing plants in the field and preserving biological repositories for DNA diversity researc…

2013

Although a variety of methods have been optimized for the collection and storage of plant specimens, most of these are not suited for field expeditions for a variety of logistic reasons. Drying specimens with silica gel in polyethylene bags is currently the standard for field-sampling methods that are suitable for subsequent DNA extraction. However, silica-gel repositories are not readily available in remote areas, and its use is not very cost-effective for the long-term storage of collections or in developing countries with limited research budgets. Salting is an ancient and traditional drying process that preserves food samples by dehydrating tissues and inhibiting water-dependent cellula…

Partitioning study of polycyclic aromatic hydrocarbons between water and some selected water-insoluble phases

2007

An investigation on the partitioning of naphthalene and phenanthrene between water and some water-insoluble phases has been carried out by Uv-vis-NIR spectrophotometry. The analysis of the experimental results emphasized the role of intermolecular interactions and structural features of the hosting phases as driving forces of the partitioning of these polycyclic aromatic hydrocarbons. The critical comparison of the resulting distribution constants allowed to evaluate the potentials of some extracting phases to set up sensitive analytical methods and/or effective environment remediation technologies.

Polish Yellow Sweet Clover (Melilotus officinalis L.) Honey, Chromatographic Fingerprints, and Chemical Markers

2017

A case study of Polish Melilotus officinalis honey was presented for the first time. Gas chromatography–mass spectrometry (GC-MS) (after steam distillation, Soxhlet extraction, ultrasonic solvent extraction, and solid phase extraction (SPE)) and targeted high performance liquid chromatography with a photodiode array detector (HPLC-PAD) were applied to determine the characteristic components of honey. While ubiquitous in most honeys, carbohydrates, terpene derivatives, and phenylacetic acid dominated in the Soxhlet extracts (25.54%) and in the application of SPE (13.04%). In addition, lumichrome (1.85%) was found, and may be considered as a marker of this honey. Due to the presence of these …

Supported liquid membrane extraction with single hollow fiber for the analysis of fluoroquinolones from environmental surface water samples

2010

Abstract In this work, the simple analytical method for the determination of four fluoroquinolone antibiotics: ciprofloxacin, enrofloxacin, norfloxacin and danofloxacin, in environmental surface water samples is described. Sample pretreatment step was performed by the application of a technique based on supported liquid membrane extraction with the configuration of single hollow fiber (HF-SLM). The HPLC system with diode array detection was used for final analysis of studied analytes. Various parameters affecting the extraction efficiency during HF-SLM enrichment, such as type of membrane diluent, pH of donor (sample) and acceptor phases, as well as an enrichment time and salt content of sa…

A low level image analysis approach to starfish detection

2003

Acquisition, filtering and toll data processing system for obtaining origin-destination matrix and travel times on highways

2012

This paper presents an acquisition, filtering and real-time toll data processing system that provides a base for resolution and generation of studies and models of behavior on highways. Crossing points estimation, speed calculation, study traffic flow, travel time estimation and stopping points can also be provided. The complexity of processing with supplied data volume makes indispensable a less relevant information filtering. This filtering can be done through indicators such as speed or nullity of fields and a performance improvement job in database level using views, materializations, partitioning and parallelism. A web application called MODA has been developed. This application make e…

Metadata to Support Data Warehouse Evolution

2009

The focus of this chapter is metadata necessary to support data warehouse evolution. We present the data warehouse framework that is able to track evolution process and adapt data warehouse schemata and data extraction, transformation, and loading (ETL) processes. We discuss the significant part of the framework, the metadata repository that stores information about the data warehouse, logical and physical schemata and their versions. We propose the physical implementation of multiversion data warehouse in a relational DBMS. For each modification of a data warehouse schema, we outline the changes that need to be made to the repository metadata and in the database.