Interactive effects of polymethyl methacrylate (PMMA) microplastics and salinity variation on a marine diatom Phaeodactylum tricornutum

Diatoms are a major group of unicellular algae that are rich in lipids and carotenoids. However, sustained research efforts are needed to improve the strain performance for high product yields towards commercialization. In this study, we generated a number of mutants of the model diatom Phaeodactylum tricornutum, a cosmopolitan species that has also been found in Nordic region, using the chemical mutagens ethyl methanesulfonate (EMS) and N-methyl-N′-nitro-N-nitrosoguanidine (NTG). We found that both chlorophyll a and neutral lipids had a significant correlation with carotenoid content and these correlations were better during exponential growth than in the stationary growth phase. Then, we studied P. tricornutum common metabolic pathways and analyzed correlated enzymatic reactions between fucoxanthin synthesis and pigmentation or lipid metabolism through a genome-scale metabolic model. The integration of the computational results with liquid chromatography-mass spectrometry data revealed key compounds underlying the correlative metabolic pathways. Approximately 1000 strains were screened using fluorescence-based high-throughput method and five mutants selected had 33% or higher total carotenoids than the wild type, in which four strains remained stable in the long term and the top mutant exhibited an increase of 69.3% in fucoxanthin content compared to the wild type. The platform described in this study may be applied to the screening of other high performing diatom strains for industrial applications.

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Interactive Effects of CO 2 , Temperature, Irradiance, and Nutrient Limitation on the Growth and Physiology of the Marine Diatom Thalassiosira pseudonana (Coscinodiscophyceae)

Journal of Phycology ◽

10.1111/jpy.13048 ◽

2020 ◽

Vol 56 (6) ◽

pp. 1614-1624

Author(s):

Edward A. Laws ◽

S. Alex McClellan ◽

Uta Passow

Keyword(s):

Nutrient Limitation ◽

Thalassiosira Pseudonana ◽

Interactive Effects ◽

Marine Diatom

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Structural basis for blue-green light harvesting and energy dissipation in diatoms

Science ◽

10.1126/science.aav0365 ◽

2019 ◽

Vol 363 (6427) ◽

pp. eaav0365 ◽

Cited By ~ 49

Author(s):

Wenda Wang ◽

Long-Jiang Yu ◽

Caizhe Xu ◽

Takashi Tomizaki ◽

Songhao Zhao ◽

...

Keyword(s):

Energy Transfer ◽

Phaeodactylum Tricornutum ◽

Light Harvesting ◽

Green Light ◽

Marine Diatom ◽

Structural Basis ◽

Aquatic Environments ◽

Efficient Energy Transfer ◽

Chl A ◽

Photosynthetic Organisms

Diatoms are abundant photosynthetic organisms in aquatic environments and contribute 40% of its primary productivity. An important factor that contributes to the success of diatoms is their fucoxanthin chlorophyll a/c-binding proteins (FCPs), which have exceptional light-harvesting and photoprotection capabilities. Here, we report the crystal structure of an FCP from the marine diatom Phaeodactylum tricornutum, which reveals the binding of seven chlorophylls (Chls) a, two Chls c, seven fucoxanthins (Fxs), and probably one diadinoxanthin within the protein scaffold. Efficient energy transfer pathways can be found between Chl a and c, and each Fx is surrounded by Chls, enabling the energy transfer and quenching via Fx highly efficient. The structure provides a basis for elucidating the mechanisms of blue-green light harvesting, energy transfer, and dissipation in diatoms.

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