Title |
Photosynthetic inhibition and oxidative stress to the toxic Phaeocystis globosa caused by a diketopiperazine isolated from products of algicidal bacterium metabolism |
Author |
Shuo Tan1, Xiaoli Hu1, Pinghe Yin1*, and Ling Zhao2* |
Address |
1Department of Chemistry, School of Life Science and technology, Jinan University, Guangzhou 510632, P. R. China, 2Key Laboratory of Water/Soil Toxic Pollutants Control and Bioremediation of Guangdong Higher Education Institutes, School of Environment, Jinan University, Guangzhou 510632, P. R. China |
Bibliography |
Journal of Microbiology, 54(5),364-375, 2016,
|
DOI |
10.1007/s12275-016-6012-0
|
Key Words |
Phaeocystis globosa, algicidal compound, cyclo-
(Pro-Gly), algicidal mechanism, oxidative stress, photosynthetic
inhibition |
Abstract |
Algicidal bacteria have been turned out to be available for inhibiting
Phaeocystis globosa which frequently caused harmful
algal blooms and threatened to economic development and
ecological balance. A marine bacterium Bacillus sp. Ts-12
exhibited significant algicidal activity against P. globosa by
indirect attack. In present study, an algicidal compound was
isolated by silica gel column, Sephadex G-15 column and
HPLC, further identified as hexahydropyrrolo[1,2-a]pyrazine-
1,4-dione, cyclo-(Pro-Gly), by GC-MS and 1H-NMR.
Cyclo-(Pro-Gly) significantly increased the level of reactive
oxygen species (ROS) within P. globosa cells, further activating
the enzymatic and non-enzymatic antioxidant systems,
including superoxide dismutase (SOD), catalase (CAT), glutathione
(GSH) and ascorbic acid (AsA). The increase in methane
dicarboxylic aldehyde (MDA) content showed that the
surplus ROS induced lipid peroxidation on membrane system.
Transmission electron microscope (TEM) and flow cytometry
(FCM) analysis revealed that cyclo-(Pro-Gly) caused
reduction of Chl-a content, destruction of cell membrane integrity,
chloroplasts and nuclear structure. Real-time PCR
assay showed that the transcriptions of photosynthesis related
genes (psbA, psbD, rbcL) were significantly inhibited. This
study indicated that cyclo-(Pro-Gly) from marine Bacillus sp.
Ts-12 exerted photosynthetic inhibition and oxidative stress
to P. globosa and eventually led to the algal cells lysis. This
algicidal compound might be potential bio-agent for controlling
P. globosa red tide. |