Detection of aquatic streptomycetes by quantitative PCR for prediction of taste-and-odour episodes in water reservoirs

Abstract

Bacteria belonging to the Streptomyces genus are known to produce several taste-and-odour compounds (TOCs), but knowledge on the abundance of streptomycetes in drinking water reservoirs and other aquatic environments is scarce. In this study, quantitative real-time polymerase chain reaction (qPCR) was applied, for the first time, to determine densities of streptomycetes in a river, at a weir and in two reservoirs in subtropical Australia. The PCR approach was optimized with respect to (a) collection of streptomycetes in water, (b) extraction of DNA, and (c) a procedure to correct for inhibition of PCR amplification by natural substances in the water. Mean densities of Streptomyces cells at the study sites varied from 225 to 45,650 cells L À1 . The highest density occurred in bottom water (8.5 m deep) of one of the reservoirs, while densities in the Brisbane River varied between 260 and 7,950 cells L À1 . At the weir site, seasonal variation in abundance in winter and spring in surface water (mean densities of 430-13,550 cells L À1 ) did not correlate with total bacterial abundance (0.9-3.5 × 10 9 cells L À1 ). The qPCR approach shows that quantitation of streptomycetes in fresh water can be successfully achieved and may prove valuable in predicting TOC episodes in aquatic systems used for drinking water supplies.

Geosmin off-flavour in pond-raised fish in southern Bangladesh and occurrence of potential off-flavour producing organisms

“…Using cultivation methods, densities of 10 2 to 10 5 streptomycetes l −1 were found in various freshwater environments (Lanciotti et al 2003, Lee et al 2011, while fluorescence in situ hybridization, targeting rRNA, indicated up to 2 × 10 9 cells l −1 in a water reservoir (Nielsen et al 2006). In contrast, using the present PCR approach, Lylloff et al (2012) only found up to 46 × 10 3 streptomycetes l −1 in various Australian freshwaters. Relative to these studies, the present abundance of Streptomyces in the Patuakhali ponds appears relatively high.…”

“…Densities of Streptomyces bacteria in the water were determined by quantitative PCR (TaqMan procedure) targeting the 23S rRNA gene according to Rintala & Nevalainen (2006) with the modifications given by Lylloff et al (2012). Genomic DNA was extracted from the 47 mm membrane filters after cutting each filter in 3 portions, using the PowerWater ® DNA isolation kit by Mobio (www.mobio.com) according to instructions by the producer.…”

“…Densities of Streptomyces on the filters were determined from calibration curves produced by amplification of DNA from known densities of spores in 2 species of Streptomyces. Possible interference on the PCR reaction by compounds in the samples was checked by measuring the amplification efficiency of a plasmid construct with and without addition of DNA extracted from the water samples (Lylloff et al 2012). …”

Establishment of quantitative PCR methods for the quantification of geosmin-producing potential and Anabaena sp. in freshwater systems

“…Since then the expression of these genes has been studied in a single strain of Anabaena (Giglio et al, 2011), which was demonstrated that the expression of the geosmin gene appears to be constitutive in nature. While in recent years some studies established quantitative PCR assays to detect and measure the production of geosmin by Streptomycetes in the environment (Auffret et al, 2011;Lylloff et al, 2012); to the best of our knowledge, no peer reviewed study has displayed a quantitative PCR assay to detect the production of geosmin specifically by cyanobacteria. The present study is the first qPCR assays for the detection and quantification of the cyanobacterial geosmin synthase in waters.…”

Identification and expression analysis of the gene associated with geosmin production in Lyngbya kuetzingii UTEX 1547 (cyanobacteria)

“…quantification of geosmin-producing Streptomyces (Auffret et al, 2011;Lylloff et al, 2012). However, the biosynthesis of geosmin by cyanobacteria has received much attention recently.…”