DBPapers
DOI: 10.5593/sgem2012/s20.v5088

QUANTIFICATION OF CELLS CAPABLE OF GROWTH AND MULTIPLICATION USING DIRECT VIABLE COUNT METHOD IN FILAMENTOUS AND UNICELLULARCYANOBACTERIA

I. SARCHIZIAN, I. ARDELEAN
Wednesday 1 August 2012 by Libadmin2012

References: 12th International Multidisciplinary Scientific GeoConference, www.sgem.org, SGEM2012 Conference Proceedings/ ISSN 1314-2704, June 17-23, 2012, Vol. 5, 655 - 662 pp

ABSTRACT

This paper presents the results concerning the quantification of cyanobacterial cells
capable of cellular growth and multiplication using the direct viable count method
(DVC). During incubation of cyanobacterial samples in the presence of nalidixic acid as
inhibitor of DNA replication , all other metabolic properties remain active. Viable cells
may continue to metabolize nutrients and grow but will not be able to divide, thus
becoming more elongated after incubation whereas inactive cells do not elongate during
the incubation period. Measurements of cells size were performed using two automatic
software Image J to measure cell length and CellC software for cell quantification in
light microscopy, compared with manual counting and measuring. The results show that
the medium cell size increases from 1.81 μm to 3.35 μm in 84 hours of light incubation
with nalidixic acid . Up to our knowledge this is the first report on DVC applied to
filamentous cyanobacteria. The method was also used on the unicellular
cyanobacterium Synechocystis PCC 6803 where the results were compared with growth
rate calculated taking into account the increase in optical density.

Keywords: direct viable count, unicellular cyanobacteria, filamentous heterocystous
cyanobacteria, digital image analysis.