A gene expression study on strains of Nostoc (Cyanobacteria)
revealing antimicrobial activity under mixotrophic
B. Nowruzi1*, R. A. Khavari-Nejad1,2,
F. Najafi1 and T.
of Biology, Faculty of Science, Tarbiat Moallem University,
of Biology, Science and Research Branch, Islamic Azad
University, Tehran, Iran.
of Applied Chemistry and Microbiology, University of
Helsinki, P. O. Box 56, Viikki Biocenter, Viikinkaari 9,
FIN-00014 Helsinki, Finland.
of Biotechnology, Shahid Beheshti University of Medical
Sciences, Tehran, Iran.
and Molecular Biology Research Center, Shahid Beheshti
University of Medical Sciences, Tehran, Iran.
*Corresponding author. E-mail:
+358-(0)9-191 59376, +358-(0) 417004519.
Accepted 7 May, 2012
Cyanobacteria are well known
for their production of a multitude of highly allelopathic
compounds. These products have features such as
incorporation of non-proteinogenic amino acids which are
characteristics of peptides biosynthesized by non-ribosomal
peptide synthetases (NRPSs).
Some of these peptides have acetate-derived moieties,
suggesting that their biosynthesis also involves polyketide
Among the photosynthetic microorganisms, cyanobacteria
belonging to the genus Nostoc are regarded as good
candidates for producing biologically active secondary
metabolites. Aiming at the
maximization in the production of natural product, we
compared autotrophic, and mixotrophic growth at high light
intensity of two Nostoc species in relation to the
production of bioactive compounds with the antimicrobial
activity at different source of sugar. Glucose
to be the best substrate for
production of high natural product when compared with
sucrose. Also, the rate of biomass production and
antimicrobial activity was reaching ~2.0 to 2.5 and ~1.5
times greater than that of the autotrophic and sucrose grown
cultures, respectively. Also, we conduct a combined
polymerase chain reaction (PCR). The sequences presented in
deposited in GenBank and had
accession numbers JF795278 and JF795279 (NRPS A domains) and
JF795280 and JF795281 (PKS KS domains). Computer modeling
and phylogenetic analysis was conducted to predict the
putative amino acid recognized by the unknown adenylation
domain in the NRPS sequences.
This study highlights the importance of environmental and
nutrimental factors in
maximization of antibiotic production of two Nostoc
Peptide synthetase gene, polyketide synthase gene, Nostoc,
secondary metabolites, mixotrophic conditions.