Jingrang Lu
U.S. Environmental Protection Agency, USA
Title: qPCR and RT-qPCR of harmful cyanobacteria at Lake Harsha, Ohio, during summer
Biography
Biography: Jingrang Lu
Abstract
Cyanobacteria blooms have increased in recent years and are becoming a greater public concern due to their potentialrnecological and health impacts. Detection of toxic cyanobacteria using qPCR and RT-qPCR allows for the rapid identifi cationrnof blooms by combining specifi city and sensitivity with speed and high sample processing capability. Toxic cyanobacteria fromrnthe water samples of fi ve sites in Lake Harsha, which is used for local recreational activities and as a source of drinking water,rnwere detected using a panel of qPCR assays for most of toxin-producers (HEP and CD1) or only toxic Microcystis spp. (mcyGrnand mcyA-MS) targeting the toxin-producing genes of mcyA, mcyE, ndaF and mcyG. Overall performance of the four assaysrnwere highly correlated with each other for DNA along weekly and daily samples, indicating similar level of copy numbers andrnamplifi cation effi ciency of the targeted genes. Th e quantity of total toxic cyanobacteria reached >108 cell L-1 in early June andrnremained at high density until the end of July. During this period, the signals of qPCR between HEP and mcyG or mcyAMSrnwere in agreement and demonstrated that Microcystis spp. dominated the toxin producers. Before this period, the lowerrnamount of toxic cyanobacteria refl ected by HEP and CD1, were non- Microcystis spp., while aft er this period approximatelyrnonly half of Microcystis spp. accounted for the total toxin producers. RT-qPCR results showed the same trend as qPCR but withrnhigher variations in assays for Microcystis spp., indicating potential toxins were produced mainly by Microcystis spp. Generallyrnmuch lower signals of qPCR and RT-qPCR were detected from deep water than surface water suggesting that the majority ofrntoxins were generated from surface water. Further analysis will be performed with microscopic and physiochemical data andrntoxin measurement to determine future development of molecular tools and its application to monitoring toxic cyanobacteria.