References
1. Mohr O'Hara, C., Weinstein, M. P., and Miller, J. M. 2003 Manual and automated systems for detection and identification of microorganisms, in Manual of Clinical Microbiology, 8th Ed. Murray, P. R., ed. , ASM, Washington, DC, pp. 185-207. 2. Andreotti, P. E., Ludwig, G. V., Peruski, A. H., Tuite, J. J., Morse, S. S., and Peruski, L. F. Jr. 2003 Immunoassay of infectious agents. Biotechniques 35, 850-859. 3. De Vos, D., Lim A., Pirnay, J. P., et al. 1997 Direct detection and identification of...
Nwadiuto Esiobu
Environmental monitoring and public health risk assessments require methods that are rapid and quantitative with defined sensitivity and specificity thresholds. Although several molecular techniques have been developed to rapidly detect bacteria in complex matrices, the challenge to simultaneously detect and enumerate only viable cells remains a limiting factor to their routine application. This chapter describes the use of peroxi-dase-labeled peptide nucleic acid PNA probes to simultaneously...
DNA Purification
The classical way of purifying nucleic acids from complex-, inhibitor-, and protein-containing solutions is to apply organic solvents such as phenol chloroform 33 . Other organic solvents such as chloroform or ether can be used to separate, for instance, fat from the aqueous DNA-containing phase. For algal and plant materials where co-purification of polysaccharides together with DNA may be a problem, the polysaccharides can be selectively precipitated with cetyl trimethyl ammonium bromide 9 ....
Miriam M Ngundi and Chris R Taitt
The Naval Research Laboratory has developed an array-based biosensor system capable of detecting multiple pathogenic and toxic species in complex matrices. Sandwich fluoroimmunoassays are performed on the surface of a patterned microscope slide that acts as an optical waveguide. Fluorescence from immunocomplexes formed on the slide surface is excited using the evanescent field, an electromagnetic component of light, and the pattern of fluorescence is imaged using a charge-coupled device camera....
Justine Fitzmaurice
Escherichia coli O157 H7 is a highly virulent pathogen that causes severe food poisoning in humans. Many outbreaks involving this pathogen have been linked to minced beef. A protocol is presented here to detect E. coli O157 H7 in minced beef. The method consists of an enrichment step in modified tryptone soya broth, followed by immunomagnetic separation and extraction of deoxyribonucleic acid. Real-time polymearse chain reaction, using hybridization probes, is used to detect the verotoxin genes...
Notes
1. Aliquotting of this reagent under nitrogen into small lt 3 mL amber vials is recommended. Allow the desiccator chamber to come to room temperature before opening. Likewise, allow each aliquot to come to room temperature. After opening a stock bottle of toluene, store it in a glovebag. Prepare the silane-toluene mix immediately before use. Silane-toluene mix forms a polymerized chemical layer on glassware. All glassware used during silanization must be rinsed with acetone store the waste in a...
Molecular Resistance Testing
Modern medicine is facing an increasingly important problem, namely, the threat from multidrug-resistant bacteria 60 . The emergence and evolution of drug resistance is a complex and multifactorial phenomenon that requires a multidisciplinary approach if it is to be kept under control 61 . This approach will be a challenge given that the phenomenon of antibiotic resistance can be viewed as a typical emergent characteristic of a dynamic, highly complex, and self-organizing system evolving at the...
RealTime PCR
Oligonucleotide primers and fluorescence-labeled hybridization probes are designed for amplification and sequence-specific detection of both a 188-bp fragment within the mecA gene and a 178-bp fragment within the S. aureus-specific Sa442 gene see Note 5 . Nucleotide sequences and positions are listed in Table 1. Lyophilized primers are diluted in PCR-grade water see Note 6 . Concentrations of the stock solution are listed in Table 2. 1. Place the required number of LightCycler Capillaries...
Introduction Jda
A biosensor is a device that uses biological recognition molecules to detect and identify a target with high selectivity and sensitivity. The most commonly used biological molecules in sensor technology are antibodies because of their selective nature toward their target antigen . The immunological basis of immunosensors makes them highly specific, often highly sensitive, and not dependent on sample cleanup or preparation. In recent years, there has been advancement in the development and...