TY  - JOUR
A1  - Smith, Sarah R.
A1  - Dupont, Chris L.
A1  - McCarthy, James K.
A1  - Broddrick, Jared T.
A1  - Obornik, Miroslav
A1  - Horak, Ales
A1  - Füssy, Zoltán
A1  - Cihlar, Jaromir
A1  - Kleessen, Sabrina
A1  - Zheng, Hong
A1  - McCrow, John P.
A1  - Hixson, Kim K.
A1  - Araujo, Wagner L.
A1  - Nunes-Nesi, Adriano
A1  - Fernie, Alisdair R.
A1  - Nikoloski, Zoran
A1  - Palsson, Bernhard O.
A1  - Allen, Andrew E.
T1  - Evolution and regulation of nitrogen flux through compartmentalized metabolic networks in a marine diatom
JF  - Nature Communications
N2  - Diatoms outcompete other phytoplankton for nitrate, yet little is known about the mechanisms underpinning this ability. Genomes and genome-enabled studies have shown that diatoms possess unique features of nitrogen metabolism however, the implications for nutrient utilization and growth are poorly understood. Using a combination of transcriptomics, proteomics, metabolomics, fluxomics, and flux balance analysis to examine short-term shifts in nitrogen utilization in the model pennate diatom in Phaeodactylum tricornutum, we obtained a systems-level understanding of assimilation and intracellular distribution of nitrogen. Chloroplasts and mitochondria are energetically integrated at the critical intersection of carbon and nitrogen metabolism in diatoms. Pathways involved in this integration are organelle-localized GS-GOGAT cycles, aspartate and alanine systems for amino moiety exchange, and a split-organelle arginine biosynthesis pathway that clarifies the role of the diatom urea cycle. This unique configuration allows diatoms to efficiently adjust to changing nitrogen status, conferring an ecological advantage over other phytoplankton taxa.
KW  - Biochemistry
KW  - Computational biology and bioinformatics
KW  - Evolution
KW  - Microbiology
KW  - Molecular biology
Y1  - 2019
U6  - https://doi.org/10.1038/s41467-019-12407-y
SN  - 2041-1723
VL  - 10
PB  - Nature Publ. Group
CY  - London
ER  - 
TY  - JOUR
A1  - Finke, Hannah
A1  - Wandt, Viktoria Klara Veronika
A1  - Ebert, Franziska
A1  - Guttenberger, Nikolaus
A1  - Glabonjat, Ronald A.
A1  - Stiboller, Michael
A1  - Francesconi, Kevin A.
A1  - Raber, Georg
A1  - Schwerdtle, Tanja
T1  - Toxicological assessment of arsenic-containing phosphatidylcholines in HepG2 cells
N2  - Arsenolipids include a wide range of organic arsenic species that occur naturally in seafood and thereby contribute to human arsenic exposure. Recently arsenic-containing phosphatidylcholines (AsPCs) were identified in caviar, fish, and algae. In this first toxicological assessment of AsPCs, we investigated the stability of both the oxo- and thioxo-form of an AsPC under experimental conditions, and analyzed cell viability, indicators of genotoxicity and biotransformation in human liver cancer cells (HepG2). Precise toxicity data could not be obtained owing to the low solubility in the cell culture medium of the thioxo-form, and the ease of hydrolysis of the oxo-form, and to a lesser degree the thioxo-form. Hydrolysis resulted amongst others in the respective constituent arsenic-containing fatty acid (AsFA). Incubation of the cells with oxo-AsPC resulted in a toxicity similar to that determined for the hydrolysis product oxo-AsFA alone, and there were no indices for genotoxicity. Furthermore, the oxo-AsPC was readily taken up by the cells resulting in high cellular arsenic concentrations (50 μM incubation: 1112 ± 146 μM As cellular), whereas the thioxo-AsPC was substantially less bioavailable (50 μM incubation: 293 ± 115 μM As cellular). Speciation analysis revealed biotransformation of the AsPCs to a series of AsFAs in the culture medium, and, in the case of the oxo-AsPC, to as yet unidentified arsenic species in cell pellets. The results reveal the difficulty of toxicity studies of AsPCs in vitro, indicate that their toxicity might be largely governed by their arsenic fatty acid content and suggest a multifaceted human metabolism of food derived complex arsenolipids.
KW  - Biochemistry
KW  - Biological Sciences
KW  - Science and Mathematics
KW  - Books
KW  - Journals
Y1  - 2020
U6  - https://doi.org/10.1039/d0mt00073f
VL  - 12
IS  - 7
SP  - 1159
EP  - 1170
PB  - Oxford University
CY  - Cambridge
ER  -