title: Development of a chip assay and quantitative PCR for detecting microcystin synthetase E gene expression.
abstract: The chip and quantitative real-time PCR (qPCR) assays were optimized to study the expression of microcystin biosynthesis genes (mcy) with RNA samples extracted from cyanobacterial strains and environmental water samples. Both microcystin-producing Anabaena and Microcystis were identified in Lake Tuusulanjärvi samples. Microcystis transcribed the mcyE genes throughout the summer of 2006, while expression by Anabaena became evident later in August and September. Active mcyE gene expression was also detectable when microcystin concentrations were very low. Detection of Anabaena mcyE transcripts by qPCR, as well as certain cyanobacterial 16S rRNAs with the chip assay, showed slightly reduced sensitivity compared with the DNA analyses. In contrast, even groups undetectable or present in low quantities as determined by microscopy could be identified with the chip assay from DNA samples. The methods introduced add to the previously scarce repertoire of applications for mcy expression profiling in environmental samples and enable in situ studies of regulation of microcystin synthesis in response to environmental factors.
authors.affiliation: Department of Food and Environmental Sciences, Division of Microbiology, University of Helsinki, Viikki Biocenter 1, P.O. Box 56, FI-00014 Helsinki, Finland.
authors.forename: Hanna
authors.initials: H
authors.lastname: Sipari
authors.forename: Anne
authors.initials: A
authors.lastname: Rantala-Ylinen
authors.forename: Jouni
authors.initials: J
authors.lastname: Jokela
authors.forename: Ilona
authors.initials: I
authors.lastname: Oksanen
authors.forename: Kaarina
authors.initials: K
authors.lastname: Sivonen
mesh_terms: D017033:Anabaena / Q000201:enzymology* / Q000302:isolation & purification; D001426:Bacterial Proteins / Q000096:biosynthesis; D001431:Bacteriological Techniques / Q000379:methods; D004783:Environmental Microbiology; D020869:Gene Expression Profiling / Q000379:methods*; D008025:Ligases / Q000096:biosynthesis*; D052998:Microcystins / Q000096:biosynthesis*; D046931:Microcystis / Q000201:enzymology* / Q000302:isolation & purification; D020411:Oligonucleotide Array Sequence Analysis / Q000379:methods*; D016133:Polymerase Chain Reaction / Q000379:methods*; D012680:Sensitivity and Specificity
chemical_list: D001426:Bacterial Proteins; D052998:Microcystins; C078588:microcystin; D008025:Ligases
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