Effect of environmental factors on the synthesis of scytonemin, a UV-screening pigment, in a cyanobacterium (Chroococcidiopsis sp.).
Abstract. The UV-screening pigment scytonemin is found in many species of ensheathed cyanobacteria. Past work has shown that the pigment is synthesized in response to exposure to UV-A irradiance. This study investigated the effect of other correlated stress factors including heat, osmotic and oxidative stress on the synthesis of scytonemin in a clonal cyanobacterial isolate ( Chroococcidiopsis sp.) from an epilithic desert crust. Stress experiments were carried out both in conjunction with UV-A irradiance and in isolation. Increases in both temperature and photooxidative conditions in conjunction with UV-A caused a synergistic increase in the rate of scytonemin production. In contrast, increased salt concentration under UV-A irradiance inhibited scytonemin synthesis. However, unlike the responses to temperature and oxidative stress, cells synthesized low levels of scytonemin under osmotic stress in the absence of scytonemin-inducing irradiance. These results suggest that scytonemin induction may be regulated as a part of a complex stress response pathway in which multiple environmental signals affect its synthesis.
Dillon
Jesse G
JG
Department of Biology, University of Oregon, Eugene, 97403, USA.
Tatsumi
Cecelia M
CM
Tandingan
Patrick G
PG
Castenholz
Richard W
RW
D000458:Cyanobacteria / Q000378:metabolism*; D007211:Indoles / Q000378:metabolism*; D009995:Osmosis; D018384:Oxidative Stress; D010636:Phenols / Q000378:metabolism*; D010860:Pigments, Biological / Q000096:biosynthesis*; D013473:Sunscreening Agents / Q000378:metabolism*; D013696:Temperature
D007211:Indoles; D010636:Phenols; D010860:Pigments, Biological; D013473:Sunscreening Agents; C083368:scytonemin