Stable transformation of chlorella and it's potential efficacy as a bioreactor
Chlorella is a unicellular green alga that grows rapidly, is easy to manipulate and is inexpensive to maintain. Like E. coli the cells can be grown in either liquid culture or on agar plates on which they form single colonies for efficient selection of individual clones. Unlike E. co/t, Chlorella is a eukaryote in which proteins can be expressed from the gene as well as the cDNA and can be postranslationally modified. These characteristics make this organism ideally suitable for use as a bioreactor. We have isolated the Chlorella nitrate reductase (NR) gene and using micro projectile bombardment have stably transformed Chlorella NR mutants. Using the Biolistic PDS-100/He system from Bio Rad, up to eighteen transformants per 3 x 107 cells were obtained using 1100 psi, and Tungsten beads coated with 2 μg of DNA. We are currently working on a system for expressing biologically useful proteins in Chlorella under the control of the NR inducible promoter. Under repressed conditions, when ammonia is present in the media, no nitrate reductase mRNA is detectable. Upon the removal of ammonia and addition of nitrate, inducing conditions, rapid accumulation of NR mRNA occurs. This will allow for the expression of exogenous proteins under tight control.
Cannons, AC; Dawson, HN; Burlingame, R; Solomonson, LP
Volume / Issue
International Standard Serial Number (ISSN)