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Whole-cell response to nitrogen deprivation in the diatom Phaeodactylum tricornutum.

Alipanah L, Rohloff J, Winge P, Bones AM, Brembu T - J. Exp. Bot. (2015)

Bottom Line: Physiological and metabolite measurements indicated that the photosynthetic capacity and chlorophyll content of the cells decreased, while neutral lipids increased in N-deprived cultures.Following N deprivation, reduced biosynthesis and increased recycling of N compounds like amino acids, proteins, and nucleic acids was observed at the transcript level.The majority of the genes associated with photosynthesis and chlorophyll biosynthesis were also repressed.

View Article: PubMed Central - PubMed

Affiliation: Department of Biology, Norwegian University of Science and Technology, N-7491 Trondheim, Norway.

No MeSH data available.


Cellular pathways and processes affected under N deprivation in P. tricornutum. Metabolites detected are indicated by a blue box frame. Red, blue,and black text indicates up-, down-, and no regulation of pathways, genes, or metabolites by N deprivation, respectively. 3-PGA, 3-phosphoglycerate; CA, carbonic anhydrase; ICL, isocitrate lyase; MLS, malate synthase; OPPP, oxidative pentose phosphate pathway; PEP, phosphoenolpyruvate; PK, pyruvate kinase; PPdK, pyruvate orthophosphate dikinase; RuBP, ribulose-1,5-bisphosphate.
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Figure 6: Cellular pathways and processes affected under N deprivation in P. tricornutum. Metabolites detected are indicated by a blue box frame. Red, blue,and black text indicates up-, down-, and no regulation of pathways, genes, or metabolites by N deprivation, respectively. 3-PGA, 3-phosphoglycerate; CA, carbonic anhydrase; ICL, isocitrate lyase; MLS, malate synthase; OPPP, oxidative pentose phosphate pathway; PEP, phosphoenolpyruvate; PK, pyruvate kinase; PPdK, pyruvate orthophosphate dikinase; RuBP, ribulose-1,5-bisphosphate.

Mentions: Downregulation of several genes connected to the biophysical carbon-concentrating mechanism was observed in N-deprived cells. Of five carbonic anhydrase (CA) genes related to the biophysical carbon-concentrating mechanism that were significantly regulated 72h after N deprivation (Supplementary Dataset S1), transcript levels of CA-III and two β-CAs (PtCa1 and PtCa2) decreased. A chloroplast bicarbonate transporter (SLC4A_1) was also repressed. In accordance with the β-CA and SLC4A_1 downregulation, a majority of the genes encoding enzymes of the Calvin cycle were downregulated (Figs 4 and 6). Upregulation of several transcripts encoding enzymes involved in the mitochondrial decarboxylation under N-deprived conditions was observed in N-deprived cells (Supplementary Dataset S1). Downregulation of plastid-localized pyruvate carboxylase 2 (PYC2) was confirmed by qRT-PCR analysis (Supplementary Fig. S2).


Whole-cell response to nitrogen deprivation in the diatom Phaeodactylum tricornutum.

Alipanah L, Rohloff J, Winge P, Bones AM, Brembu T - J. Exp. Bot. (2015)

Cellular pathways and processes affected under N deprivation in P. tricornutum. Metabolites detected are indicated by a blue box frame. Red, blue,and black text indicates up-, down-, and no regulation of pathways, genes, or metabolites by N deprivation, respectively. 3-PGA, 3-phosphoglycerate; CA, carbonic anhydrase; ICL, isocitrate lyase; MLS, malate synthase; OPPP, oxidative pentose phosphate pathway; PEP, phosphoenolpyruvate; PK, pyruvate kinase; PPdK, pyruvate orthophosphate dikinase; RuBP, ribulose-1,5-bisphosphate.
© Copyright Policy - creative-commons
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4588885&req=5

Figure 6: Cellular pathways and processes affected under N deprivation in P. tricornutum. Metabolites detected are indicated by a blue box frame. Red, blue,and black text indicates up-, down-, and no regulation of pathways, genes, or metabolites by N deprivation, respectively. 3-PGA, 3-phosphoglycerate; CA, carbonic anhydrase; ICL, isocitrate lyase; MLS, malate synthase; OPPP, oxidative pentose phosphate pathway; PEP, phosphoenolpyruvate; PK, pyruvate kinase; PPdK, pyruvate orthophosphate dikinase; RuBP, ribulose-1,5-bisphosphate.
Mentions: Downregulation of several genes connected to the biophysical carbon-concentrating mechanism was observed in N-deprived cells. Of five carbonic anhydrase (CA) genes related to the biophysical carbon-concentrating mechanism that were significantly regulated 72h after N deprivation (Supplementary Dataset S1), transcript levels of CA-III and two β-CAs (PtCa1 and PtCa2) decreased. A chloroplast bicarbonate transporter (SLC4A_1) was also repressed. In accordance with the β-CA and SLC4A_1 downregulation, a majority of the genes encoding enzymes of the Calvin cycle were downregulated (Figs 4 and 6). Upregulation of several transcripts encoding enzymes involved in the mitochondrial decarboxylation under N-deprived conditions was observed in N-deprived cells (Supplementary Dataset S1). Downregulation of plastid-localized pyruvate carboxylase 2 (PYC2) was confirmed by qRT-PCR analysis (Supplementary Fig. S2).

Bottom Line: Physiological and metabolite measurements indicated that the photosynthetic capacity and chlorophyll content of the cells decreased, while neutral lipids increased in N-deprived cultures.Following N deprivation, reduced biosynthesis and increased recycling of N compounds like amino acids, proteins, and nucleic acids was observed at the transcript level.The majority of the genes associated with photosynthesis and chlorophyll biosynthesis were also repressed.

View Article: PubMed Central - PubMed

Affiliation: Department of Biology, Norwegian University of Science and Technology, N-7491 Trondheim, Norway.

No MeSH data available.