Detection of nitric oxide in culture media and studies on nitric oxide formation by marine microalgae.
BACKGROUND
Multiple functions of nitric oxide (NO) in organisms and its special function and role in the atmosphere were investigated. In this study, marine microalga culture-medium NO concentrations were detected and studied in order to find the laws governing NO release by marine microalgae and relevant material was collected for discussion on the production mechanisms.


METHODS
NO concentrations in culture media of the marine microalgae Platymonas subcordiformis, Skeletonema costatum, and Gymnodinium sp. were detected and other media parameters, such as nutrients concentrations, Chl-a, alga cell density, and pH, were also measured concurrently.


RESULTS
The NO concentrations in culture media of the marine microalgae Platymonas subcordiformis, Skeletonema costatum, and Gymnodinium sp. were detected and found to be about 10(-8)-10(-9) mol/l. The relationships between NO and nutrients and NO and pH were discussed. It was found that "NO" could serve as the message factor of microalga growth status. Experiments showed that factors affecting alga growth, such as trace elements, light, temperature, and salinity, all affected the culture-medium NO concentration. At the same time, an environmental stimulus could give rise to sudden NO peaks, with NO being a signal molecule of marine microalga stress response.


CONCLUSIONS
These results indicated that low concentrations of NO were produced by marine phytoplankton (microalgae) under the condition of normal growth. NO is a message factor of microalga growth and is also a signal molecule of stress response.
Zhang
Zheng-Bin
ZB
Institute of Marine Chemistry, Ocean University of China, Qingdao, China. zhangzb@ouc.edu.cn
Liu
Chun-Ying
CY
Wu
Zhen-Zhen
ZZ
Xing
Lei
L
Li
Pei-Feng
PF
D000818:Animals; D000460:Chlorophyta / Q000378:metabolism; D003470:Culture Media; D017377:Diatoms / Q000378:metabolism; D004141:Dinoflagellida / Q000378:metabolism; D056890:Eukaryota / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D008954:Models, Biological; D009569:Nitric Oxide / Q000032:analysis / Q000096:biosynthesis*; D010839:Phytoplankton / Q000378:metabolism; D010937:Plant Growth Regulators / Q000494:pharmacology; D020156:Salicylic Acid / Q000494:pharmacology; D015398:Signal Transduction; D014131:Trace Elements / Q000494:pharmacology
D003470:Culture Media; D010937:Plant Growth Regulators; D014131:Trace Elements; D009569:Nitric Oxide; D020156:Salicylic Acid