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Category: Environmental Microbiology
Analysis of Bioaerosol Samples, Page 1 of 2
< Previous page | Next page > /docserver/preview/fulltext/10.1128/9781555818821/9781555818821.ch3.2.3-1.gif /docserver/preview/fulltext/10.1128/9781555818821/9781555818821.ch3.2.3-2.gifAbstract:
Respiratory exposure to certain pathogenic or toxigenic microorganisms and/or elevated concentrations of environmental organisms could result in health effects, such as allergic reactions, irritant responses, toxicosis, and respiratory illness. Determination of the concentration and composition of bioaerosols in indoor environments is necessary for assessment of contamination levels and to estimate potential exposure of occupants. The need for accurate measurement of bioaerosols has received increased attention in recent years owing to concerns with mold contamination in indoor environments and the threat of bioterrorism. Sample analysis methods include culture, microscopic, biochemical, immunological, or molecular biological assays. Traditionally, airborne microorganisms have been analyzed by culturable and microscopic total count determinations. However, limitations to both of these methods have led to the development of techniques that can increase the sensitivity and accuracy of bioaerosol monitoring. The selection of an analysis method is a critical component of a bioaerosol sampling plan, and it should be designated before air sampling is conducted. Factors which influence the choice of an analytical method include the cost and length of time required for analysis, the sensitivity and specificity of the analysis method, the sampling methods to be utilized, and the expected characteristics of the bioaerosol of interest. The purpose of this chapter is to present an overview of available methods for the analysis of bioaerosols. In addition, the potential use of enhanced monitoring of bioaerosols with polymerase chain reaction, biochemical, and immunological assays is discussed.
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Diagrams illustrating competitive polymerase chain reaction (cPCR) and quantitative PCR (qPCR). (a) In cPCR, the target template and the internal control DNA compete for the oligonucleotide primers during the PCR assay. Post-PCR manipulations are required to separate the target and competitor products and determine the ratio between them (i.e., final product concentrations). (b) In qPCR, a fluorescent probe anneals to the target DNA between the specific primer binding sites. As new DNA is synthesized, the probe is cleaved by the Taq polymerase, causing it to fluoresce, and the amount of fluorescence is used to measure the initial target DNA concentration. doi:10.1128/9781555818821.ch3.2.3.f1
Diagrams illustrating competitive polymerase chain reaction (cPCR) and quantitative PCR (qPCR). (a) In cPCR, the target template and the internal control DNA compete for the oligonucleotide primers during the PCR assay. Post-PCR manipulations are required to separate the target and competitor products and determine the ratio between them (i.e., final product concentrations). (b) In qPCR, a fluorescent probe anneals to the target DNA between the specific primer binding sites. As new DNA is synthesized, the probe is cleaved by the Taq polymerase, causing it to fluoresce, and the amount of fluorescence is used to measure the initial target DNA concentration. doi:10.1128/9781555818821.ch3.2.3.f1