Abstract
* Corresponding author. Mailing address: DSMZ-German Collection of Microorganisms and Cell Cultures GmbH, Mascheroder Weg 1b, 38124 Braunschweig, Germany. Phone: 49 531 2616 352. Fax: 49 531 2616 418. Electronic mail address: erko{at}gbf-braunschweig.de .