Genetic analysis of polyketide synthase (pkss) genes with antimicrobial activity in terrestrial cyanobacteria of the lavasan

Roghayeh sadat Hosseini,1,* Abbas akhavan sepahi,2 Bahareh nowruzi,3

1. Science and Research Branch, Islamic Azad University, Tehran
2. Islamic Azad University, Tehran North Branch, Tehran, Iran.
3. Science and Research Branch, Islamic Azad University, Tehran



Cyanobacteria are considered a promising source for new pharmaceutical lead compounds. to date, the majority of bioactive metabolites isolated from cyanobacteria have either been polyketides (pkss) or non-ribosomal peptides.


The dna sequences of the 16s rrna region were determined and the strains were named and have been deposited in genbank for getting the accession numbers. morover, computer modeling and phylogenetic analysis was conducted to analysis of polyketide synthase. lastly, to show that the presence of this gene correlates with natural product synthesis, we conducted biochemical assays to detect the presence of antimicrobial effects in organic extracts.


The extract of scytonema sp. ft11 showed more potent activity against bacillus cereus and no inhibitory effect was found against escherichia coli. moreover, antifungal activity was only seen against candida albilancs in calothrix sp. f6 and scytonema sp. ft 11. the different pattern of inhibition in the bacterial and fungal bioassays indicated that various antimicrobial substances are involved.


According to these results, it is concluded that the antibiogram bioassay and molecular detection of polyketide synthase genes may be useful techniques for the assessment of natural product -producing species and possible role of polyketide synthase enzyme complexes in the biosynthesis of biologically active compounds.


Polyketide synthase , soil cyanobacteria, antimicrobial