Extracellular cyanobacterial substances inhibit microbial growth Authors B. Heyduck-Söller Department of Marine Microbiology, Center for Environmental Research and Environmental Technology, Faculty of Biology and Chemistry, University of Bremen, Germany U. Fischer Department of Marine Microbiology, Center for Environmental Research and Environmental Technology, Faculty of Biology and Chemistry, University of Bremen, Germany Abstract Cyanobacteria are able to produce extracellular substances with different biological activities and behaviors. The marine cyanobacteria Anabaena sp. strain Hi 26 and Oscillatoria subtilissima strain Bo 62 cause significant color changes in their growth media, while viscosity of the medium is influenced by Rivularia sp. strain Bo 85 and Oscillatoria limnetica strain Flo 1. Sterile-filtered media, pregrown with the organisms mentioned above, were used to study the influence of changes in media bioactivity induced by “excreted substances” on the growth and/or morphological development of five related filamentous cyanobacterial species and on selected heterotrophic microorganisms. Cell lysis, empty sheaths, different lengths of filaments, or even single cells and a decrease in chlorophyll a and protein content were the characteristic changes obtained by such a “cyanobacterial assay.” The use of a “precultured” medium, as demonstrated in an “agar diffusion assay,” affects in varying degrees the growth of gram-positive and gram-negative heterotrophic bacteria, as well as of the yeast Saccharomyces cerevisiae. Published 2010-03-14 Issue Vol. 3 No. 4 (2000) Section Research Articles License Submission of a manuscript to International Microbiology implies: that the work described has not been published before, including publication in the World Wide Web (except in the form of an Abstract or as part of a published lecture, review, or thesis); that it is not under consideration for publication elsewhere; that all the coauthors have agreed to its publication. The corresponding author signs for and accepts responsability for releasing this material and will act on behalf of any and all coauthors regarding the editorial review and publication process.If an article is accepted for publication in International Microbiology, the authors (or other copyright holder) must transfer to the journal the right–not exclusive–to reproduce and distribute the article including reprints, translations, photographic reproductions, microform, electronic form (offline, online) or any other reproductions of similar nature. Nevertheless, all article in International Microbiology will be available on the Internet to any reader at no cost. The journal allows users to freely download, copy, print, distribute, search, and link to the full text of any article, provided the authorship and source of the published article is cited. The copyright owner's consent does not include copying for new works, or resale. In these cases, the specific written permission of International Microbiology must first be obtained.Authors are requested to create a link to the published article on the journal's website. The link must be accompanied by the following text: "The original publication is available on LINK at <http://www.im.microbios.org>. Please use the appropiate URL for the article in LINK. Articles disseminated via LINK are indexed, abstracted, and referenced by many abstracting and information services, bibliographic networks, subscription agencies, library networks, and consortia.
