TY - JOUR
T1 - Changes to the amino acid profile and proteome of the tropical freshwater microalga Chlorella sp. in response to copper stress
AU - Shakya, Manisha
AU - Silvester, Ewen
AU - Rees, Gavin
AU - Rajapaksha, Kolin Harinda
AU - Faou, Pierre
AU - Holland, Aleicia
N1 - Funding Information:
This work was supported by La Trobe University Postgraduate Research Scholarship (LTUPRS), a La Trobe University Full Fee Research Scholarship (LTUFFRS) and Ph.D. Top-Up scholarship supported by the Murray Darling Basin Joint Governments in association with the Murray-Darling Freshwater Research Centre (MDFRC/CFE). The assistance of Shimadzu Australasia (Chris Bowen and Rudi Hollander) in developing the LCMS analytical methods used here is greatly appreciated.
Publisher Copyright:
© 2022 The Authors
PY - 2022/3/15
Y1 - 2022/3/15
N2 - Contamination of freshwaters is
increasing globally, with microalgae considered one of the most
sensitive taxa to metal pollution. Here, we used 72 h bioassays to
explore the biochemical effects of copper (Cu) on the amino acid (AA)
profile and proteome of Chlorella
sp. and advance our understanding of the molecular changes that occur
in algal cells during exposure to environmentally realistic Cu
concentrations. The Cu concentrations required to inhibit algal growth
rate by 10% (EC10) and 50% (EC50) were 1.0 (0.7–1.2) µg L−1 and 2.0 (1.9–2.4) µg L−1, respectively. The AA profile of Chlorella sp. showed increases in glycine and decreases in isoleucine, leucine, valine, and arginine, with increasing Cu. Proteomic analysis revealed the modulation of several proteins involved in energy production pathways, including: photosynthesis, carbon fixation, glycolysis,
and oxidative phosphorylation, which likely assists in meeting
increased energy demands under Cu-stressed conditions. Copper exposure
also caused up-regulation of cellular processes and signalling proteins,
and the down-regulation of proteins related to ribosomal structure and
protein translation. These changes in biomolecular pathways have direct
effects on the AA profile and total protein content and provide an
explanation for the observed changes in amino acid profile, cell growth
and morphology. This study shows the complex mode of action of Cu on Chlorella under environmentally realistic Cu concentrations and highlights several potential biomarkers for future investigations.
AB - Contamination of freshwaters is
increasing globally, with microalgae considered one of the most
sensitive taxa to metal pollution. Here, we used 72 h bioassays to
explore the biochemical effects of copper (Cu) on the amino acid (AA)
profile and proteome of Chlorella
sp. and advance our understanding of the molecular changes that occur
in algal cells during exposure to environmentally realistic Cu
concentrations. The Cu concentrations required to inhibit algal growth
rate by 10% (EC10) and 50% (EC50) were 1.0 (0.7–1.2) µg L−1 and 2.0 (1.9–2.4) µg L−1, respectively. The AA profile of Chlorella sp. showed increases in glycine and decreases in isoleucine, leucine, valine, and arginine, with increasing Cu. Proteomic analysis revealed the modulation of several proteins involved in energy production pathways, including: photosynthesis, carbon fixation, glycolysis,
and oxidative phosphorylation, which likely assists in meeting
increased energy demands under Cu-stressed conditions. Copper exposure
also caused up-regulation of cellular processes and signalling proteins,
and the down-regulation of proteins related to ribosomal structure and
protein translation. These changes in biomolecular pathways have direct
effects on the AA profile and total protein content and provide an
explanation for the observed changes in amino acid profile, cell growth
and morphology. This study shows the complex mode of action of Cu on Chlorella under environmentally realistic Cu concentrations and highlights several potential biomarkers for future investigations.
KW - Aquatic toxicology
KW - Biomolecular changes
KW - Dose response
KW - Metabolic pathways
KW - Proteomics
KW - Sublethal toxicity
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U2 - 10.1016/j.ecoenv.2022.113336
DO - 10.1016/j.ecoenv.2022.113336
M3 - Article
C2 - 35228027
AN - SCOPUS:85125253845
VL - 233
JO - Ecotoxicology and Environmental Safety
JF - Ecotoxicology and Environmental Safety
SN - 0147-6513
M1 - 113336
ER -