Jingrang Lu
US Environmental Protection Agency, USA
Title: qPCR and RT-qPCR of Harmful Cyanobacteria at Lake Harsha, OH, during Summer
Biography
Biography: Jingrang Lu
Abstract
Cyanobacteria blooms have increased in recent years and are becoming a greater public concern due to their potential ecological and health impacts. Detection of toxic cyanobacteria using qPCR and RT-qPCR allows for the rapid identification of blooms by combining specificity and sensitivity with speed and high sample processing capability. Toxic cyanobacteria from the water samples of five sites in Lake Harsha, which is used for local recreational activities and as a source of drinking water, were detected using a panel of qPCR assays for most of toxin-producers (HEP and CD1) or only toxic Microcystis spp. (mcyG and mcyA-MS) targeting the toxin-producing genes of mcyA, mcyE, ndaF and mcyG. Overall performance of the four assays were highly correlated with each other for DNA along weekly and daily samples, indicating similar level of copy numbers and amplification efficiency of the targeted genes. The quantity of total toxic cyanobacteria reached >108 cell L-1 in early June and remained at high density until the end of July. During this period, the signals of qPCR between HEP and mcyG or mcyA-MS were in agreement, and demonstrated that Microcystis spp. dominated the toxin producers. Before this period, the lower amount of toxic cyanobacteria reflected by HEP and CD1 were non- Microcystis spp., while after this period approximately only half of Microcystis spp. accounted for the total toxin producers. RT-qPCR results showed the same trend as qPCR, but with higher variations in assays for Microcystis spp., indicating potential toxins were produced mainly by Microcystis spp. Generally much lower signals of qPCR and RT-qPCR were detected from deep water than surface water suggesting that the majority of toxins were generated from surface water. Further analysis will be performed with microscopic and physiochemical data and toxin measurement to determine future development of molecular tools and its application to monitoring toxic cyanobacteria.