Electrochemical detection of the toxic dinoflagellate Alexandrium ostenfeldii with a DNA-biosensor.
The steady rise of observations of harmful or toxic algal blooms throughout the world in the past decades constitute a menace for coastal ecosystems and human interests. As a consequence, a number of programs have been launched to monitor the occurrence of harmful and toxic algae. However, the identification is currently done by microscopic examination, which requires a broad taxonomic knowledge, expensive equipment and is very time consuming. In order to facilitate the identification of toxic algae, an inexpensive and easy-to-handle DNA-biosensor has been adapted for the electrochemical detection of the toxic dinoflagellate Alexandrium ostenfeldii. The detection of the toxic algae is based on a sandwich hybridisation, which is carried out on a disposable sensor chip. A set of two probes for the species-specific identification of A. ostenfeldii was developed. The specificity of the probes could be shown in dot-blot hybridisations and with the DNA-biosensor. The sensitivity of the DNA-biosensor was optimised with respect to hybridisation temperature and NaCl-concentration and a significant increase of the sensitivity of the DNA-biosensor could be obtained by a fragmentation of the rRNA prior to the hybridisation and by adding a helper oligonucleotide, which binds in close proximity to the probes to the hybridisation.
Metfies
Katja
K
Alfred Wegener Institute for Polar and Marine Research, Am Handelshafen 12, 27570 Bremerhaven, Germany. kmetfies@awi-bremerhaven.de
Huljic
Susanne
S
Lange
Martin
M
Medlin
Linda K
LK
D000818:Animals; D015374:Biosensing Techniques; D004247:DNA; D004141:Dinoflagellida / Q000235:genetics / Q000302:isolation & purification*; D006801:Humans; D015335:Molecular Probes; D012335:RNA, Ribosomal
D015335:Molecular Probes; D012335:RNA, Ribosomal; D004247:DNA