Methods and Applications

Abstract

Dehalococcoides species are responsible for the reductive dehalogenation of an impressive range of common, persistent environmental contaminants. These microorganisms are difficult to both obtain and grow in pure culture, and so are often studied while they exist in consortia using molecular techniques. In particular, a significant number of quantitative real-time PCR (qPCR) assays targeting Dehalococcoides spp. have been reported. Initial qPCR methods targeted the 16S rRNA gene, however, because strains with the same 16S rRNA gene sequence can have different dehalogenating abilities, reductive dehalogenase genes are now emerging as the most appropriate qPCR target. Quantitative PCR has been critical to our current understanding of Dehalococcoides populations; it has provided information on their growth characteristics, dehalogenating abilities and effective use in bioremediation efforts. Future qPCR research directions will likely involve method standardization, as well as continued research on the functional genes associated with Dehalococcoides populations.

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“…Let the observed vignette rating data for n individuals for vignette k be and the observed categorical response be , and the corresponding covariates be and . Then a bootstrap procedure by case resampling (Davison and Hinkley, 1997) where we can obtain B bootstrap samples as , , and for b =1,2,…, B where and are for the same object i in resample b . Then for bootstrap sample b we estimate η k , b and and β b by using expressions (2), (4) and (5) where in expression (4) we have for the individualized thresholds.…”