Studies on nitric oxide (NO) formation by the green alga Scenedesmus obliquus and the diazotrophic cyanobacterium Anabaena doliolum

Chemosphere. 1999 Oct;39(10):1601-10. doi: 10.1016/s0045-6535(99)00058-2.


This study provides preliminary evidence that NO production could be a general attribute of algae. Anabaena doliolum was found to be a better NO producer than Scenedesmus and Synechoccocus. Experiments conducted with inhibitors of photosynthesis (DCMU), ATP synthesis (DCCD), and the uncoupler (2,4-DNP) and its analog arsenate clearly revealed that inhibition of nitrite assimilation through the blockage of nitrite reductase (NiR) is primarily responsible for NO emission. A linear relationship between nitrite concentration in the culture medium and NO in the exhaust gas supports the view that accumulation of nitrite is responsible for NO formation. A failure of Scenedesmus, grown in the medium substituted with W for Mo, to produce either NO/NO-2 in light or a 'light-off' peak, and a resumption of these activities upon the addition of Mo proved beyond doubt that a functional nitrate reductase (NR) is necessary for the production of nitrite and NO by algae grown on nitrate as the nitrogen source. Moreover, the appearance of a NO peak immediately after nitrite supplementation under dark conditions in W-substituted cultures with or without glucose ruled out an enzymatic role of NR in NO emission.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • 2,4-Dinitrophenol / pharmacology
  • Anabaena / drug effects
  • Anabaena / metabolism*
  • Arsenates / pharmacology
  • Biomass
  • Chlorophyta / drug effects
  • Chlorophyta / metabolism*
  • Culture Media
  • Glucose / metabolism
  • Nitric Oxide / biosynthesis*
  • Nitrites / metabolism
  • Species Specificity
  • Uncoupling Agents / pharmacology


  • Arsenates
  • Culture Media
  • Nitrites
  • Uncoupling Agents
  • Nitric Oxide
  • Glucose
  • arsenic acid
  • 2,4-Dinitrophenol