Effect of environmental factors on the synthesis of scytonemin, a UV-screening pigment, in a cyanobacterium (Chroococcidiopsissp.)

✍ Scribed by Jesse G. Dillon; Cecelia M. Tatsumi; Patrick G. Tandingan; Richard W. Castenholz

• Book ID: 105868288
• Publisher: Springer
• Year: 2002
• Tongue: English
• Weight: 132 KB
• Volume: 177
• Category: Article
• ISSN: 0302-8933
• DOI: 10.1007/s00203-001-0395-x

✦ Synopsis

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.