Detection of Alexandrium tamarensis by rapid PCR analysis.

Alexandrium tamarensis is a toxigenic dinoflagellate found in coastal waters worldwide. A critical factor in alleviating the health and economic threats posed by this species is the development of a rapid and reliable method for detection. This study stream-lined a labor- and resource-intensive protocol for the isolation of A. tamarensis ribosomal DNA (rDNA). Subcultures of A. tamarensis were established in water samples from several coastal Atlantic sites. A commercial DNA isolation kit protocol for cultured cells was used for isolation of the dinoflagellate DNA. Samples were amplified by PCR using primers specific for a 700-bp sequence of A. tamarensis rDNA. It was determined that this method facilitated the detection of 10(-4) ng/microL of A. tamarensis DNA. Furthermore, the kit enabled A. tamarensis to be isolated from the water sources with little signal degradation. This is a valuable technique for the rapid detection of A. tamarensis, even before cell numbers are large enough for morphological identification.