Download Full Text (632 KB)

Faculty Sponsor

Dr. Tanya Soule


Department of Biology

University Affiliation

Indiana University – Purdue University Fort Wayne


As phototrophic bacteria, cyanobacteria are continually exposed to ultraviolet radiation as they harvest solar energy. In particular, long-wavelength ultraviolet radiation (UVA) damages living cells by releasing reactive oxygen species. In phototrophs, this leads to harmful photosensitized proteins and pigments. To mitigate damage to the cell, some cyanobacteria produce a UVA-absorbing pigment in the extracellular sheath, known as scytonemin. Scytonemin is a heterocyclic, dimeric molecule that is only produced upon induction by UVA. It is suspected that it is regulated by a putative two component regulatory system (TCRS). In the cyanobacterium, Nostoc punctiforme ATCC29133, the putative sensor kinase, NpF1277, is found upstream from the genes for scytonemin biosynthesis and hypothesized to regulate their induction by sensing UVA. For this project, we are inactivating NpF1277 through an in-frame gene knockout in N. punctiforme to determine the effects on scytonemin production. NpF1277 was truncated by fusion PCR and ligated into plasmid vector, pRL278. This plasmid has been transformed into E. coli UC585 and will be transferred into N. punctiforme through bi-parental conjugation. The mutant will be verified by colony PCR and the ability to produce scytonemin under UVA will be assessed. Furthermore, the expression of the TCRS, both NpF1277 (sensor kinase) and NpF1278 (response regulator), will be evaluated in response to a variety of environmental conditions, including UVA, oxidative stress, and salinity.


Biology | Life Sciences

Analysis of a Putative Histidine Kinase Associated with Sunscreen Biosynthesis in the Cyanobacterium Nostoc punctiforme ATCC 29133

Included in

Biology Commons