Journal of Methods Microbiological Journal of Microbiological Methods 39 (2000) 159–169 www.elsevier.com / locate / jmicmeth Miniprep DNA isolation from unicellular and filamentous cyanobacteria a,b, a a b b * Marli F. Fiore , David H. Moon , Siu M. Tsai , Hung Lee , Jack T. Trevors a ˜ ´ Centro de Energia Nuclear na Agricultura, Universidade de Sao Paulo, Av. Centenario 303, Caixa Postal 96, CEP 13400-970, Piracicaba SP , Brazil b Department of Environmental Biology, University of Guelph, Guelph, Ontario, Canada N1G 2 W1 Received 20 April 1999; received in revised form 16 August 1999; accepted 26 August 1999 Abstract A rapid miniprep method for isolation of DNA from 12 strains of cyanobacteria belonging to groups I, III, IV and V is described. The protocol is a modification of the methods of Boyle and Lew [Boyle, J.S., Lew, A.M., 1995. An inexpensive alternative to glassmilk for DNA purification. Trends Genet. 11, 8] and the cetyltrimethyl ammonium bromide (CTAB) extraction method of Sahgai-Maroof et al. [Sahgai-Maroof, M.A., Soliman, K.M., Jorgensen, R.A., Allard, R.W., 1984. Ribosomal DNA spacer-length polymorphisms in barley: Mendelian inheritance, chromosomal location and population dynamics. Proc. Natl. Acad. Sci. USA 81, 8014–8018]. The new method is especially useful for obtaining cyanobacterial DNA from unicellular, filamentous and filamentous branched species. The method does not require phenol extraction and the product can be used directly for PCR amplification and restriction digestion.  2000 Elsevier Science B.V. All rights reserved. Keywords: Cyanobacteria; DNA; Silica; PCR 1. Introduction crocystin, nodularin) and gas vacuoles (Carmichael, 1992; Walsby, 1994; Fiore et al., 1998). The cyanobacteria can perform oxygenic photo- Many cyanobacteria are amenable to genetic ma- synthesis and fixation of atmospheric nitrogen mak- nipulation using techniques developed for other more ing their growth requirements simple. These organ- intensively studied heterotrophic bacteria. For exam- isms are excellent candidates for producing fixed ple, some cyanobacteria (e.g., Synechocystis sp., nitrogen, secondary metabolites and biomass. Other Synechococcus sp., Anabaena sp., Plectonema physiologically important traits include resistance to boryanum) have been transformed by exogenously numerous metals and heavy metals as exhibited by added DNA (Porter, 1988) or have received plasmids some cyanobacteria growing in polluted environ- mobilized for transfer from Escherichia coli (Elhai ments and the ability to produce toxins (e.g., mi- and Wolk, 1988; Vachhani et al., 1993). Cyano- bacteria also offer a prokaryotic model system to investigate the structural and functional aspects of *Corresponding author. Tel.: 1 55-19-429-4657; fax: 1 55-19- oxygenic photosynthesis, as they possess photo- 429-4610. E-mail address: fiore@cena.usp.br (M.F. Fiore) synthetic apparatus similar to higher plants and 0167-7012 / 00 / $ – see front matter  2000 Elsevier Science B.V. All rights reserved. PII: S0167-7012(99)00110-4