scholarly journals Transcriptional regulation of microalgae for concurrent lipid overproduction and secretion

2019 ◽  
Vol 5 (1) ◽  
pp. eaau3795 ◽  
Author(s):  
Da-Wei Li ◽  
Srinivasan Balamurugan ◽  
Yu-Feng Yang ◽  
Jian-Wei Zheng ◽  
Dan Huang ◽  
...  
Keyword(s):  
Cell Wall ◽  
Chromatin Immunoprecipitation ◽  
Glucose Dehydrogenase ◽  
Cell Wall Composition ◽  
Pcr Analysis ◽  
Nannochloropsis Oceanica ◽  
Comprehensive Strategy ◽  
Lipid Secretion ◽  
Multiple Factors ◽  
Physiological Properties

Commercialization of algal lipids and biofuels is still impractical owing to the unavailability of lipogenic strains and lack of economically viable oil extraction strategies. Because lipogenesis is governed by multiple factors, success in generating industrial-suitable algal strains using conventional strategies has been limited. We report the discovery of a novel bZIP1 transcription factor, NobZIP1, whose overexpression results in a remarkable elevation of lipid accumulation and lipid secretion in a model microalgaNannochloropsis oceanica, without impairing other physiological properties. Chromatin immunoprecipitation–quantitative PCR analysis revealed that the key genes up- and down-regulated by NobZIP1 are involved in lipogenesis and cell wall polymer synthesis, respectively, which, in turn, induce lipid overproduction and secretion. Among these regulated genes, UDP-glucose dehydrogenase was shown to alter cell wall composition, thus also boosting lipid secretion. In summary, these results offer a comprehensive strategy for concurrent lipid overproduction and secretion, strongly increasing the commercial potential of microalgae.

scholarly journals Internode structure and cell wall composition in maturing tillers of switchgrass (Panicum virgatum. L)

2007 ◽  
Vol 98 (16) ◽  
pp. 2985-2992 ◽  
Author(s):  
Gautam Sarath ◽  
Lisa M. Baird ◽  
Kenneth P. Vogel ◽  
Robert B. Mitchell
Keyword(s):  
Cell Wall ◽  
Panicum Virgatum ◽  
Cell Wall Composition ◽  
Panicum Virgatum L

scholarly journals Correction to: Cell wall and organelle modifications during nitrogen starvation in Nannochloropsis oceanica F&M-M24

2021 ◽  
Author(s):  
Bianca Roncaglia ◽  
Alessio Papini ◽  
Graziella Chini Zittelli ◽  
Liliana Rodolfi ◽  
Mario R. Tredici
Keyword(s):  
Cell Wall ◽  
Nitrogen Starvation ◽  
Nannochloropsis Oceanica

scholarly journals Cell wall and organelle modifications during nitrogen starvation in Nannochloropsis oceanica F&M-M24

2021 ◽  
Author(s):  
Roncaglia Bianca ◽  
Papini Alessio ◽  
Chini Zittelli Graziella ◽  
Rodolfi Liliana ◽  
Mario R. Tredici
Keyword(s):  
Cell Wall ◽  
Wall Thickness ◽  
Lipid Droplets ◽  
Nitrogen Starvation ◽  
Photosynthetic Apparatus ◽  
Ultrastructural Changes ◽  
Total Biomass ◽  
Nannochloropsis Oceanica ◽  
Final Phase ◽  
Cell Functions

AbstractNannochloropsis oceanica F&M-M24 is able to increase its lipid content during nitrogen starvation to more than 50% of the total biomass. We investigated the ultrastructural changes and the variation in the content of main cell biomolecules that accompany the final phase of lipid accumulation. Nitrogen starvation induced a first phase of thylakoid disruption followed by chloroplast macroautophagy and formation of lipid droplets. During this phase, the total amount of proteins decreased by one-third, while carbohydrates decreased by 12–13%, suggesting that lipid droplets were formed by remodelling of chloroplast membranes and synthesis of fatty acids from carbohydrates and amino acids. The change in mitochondrial ultrastructure suggests also that these organelles were involved in the process. The cell wall increased its thickness and changed its structure during starvation, indicating that a disruption process could be partially affected by the increase in wall thickness for biomolecules recovery from starved cells. The wall thickness in strain F&M-M24 was much lower than that observed in other strains of N. oceanica, showing a possible advantage of this strain for the purpose of biomolecules extraction. The modifications following starvation were interpreted as a response to reduction of availability of a key nutrient (nitrogen). The result is a prolonged survival in quiescence until an improvement of the environmental conditions (nutrient availability) allows the rebuilding of the photosynthetic apparatus and the full recovery of cell functions.

CO2 enrichment leads to altered cell wall composition in plants of Pfaffia glomerata (Spreng.) Pedersen (Amaranthaceae)

2021 ◽  
Author(s):  
Eliza Louback ◽  
Diego Silva Batista ◽  
Tiago Augusto Rodrigues Pereira ◽  
Talita Cristina Mamedes-Rodrigues ◽  
Tatiane Dulcineia Silva ◽  
...  
Keyword(s):  
Cell Wall ◽  
Co2 Enrichment ◽  
Cell Wall Composition ◽  
Pfaffia Glomerata ◽  
Altered Cell

Maize Stover and Cob Cell Wall Composition and Ethanol Potential as Affected by Nitrogen Fertilization

2015 ◽  
Vol 8 (3) ◽  
pp. 1352-1361 ◽  
Author(s):  
Aaron J. Sindelar ◽  
Craig C. Sheaffer ◽  
John A. Lamb ◽  
Hans-Joachim G. Jung ◽  
Carl J. Rosen
Keyword(s):  
Cell Wall ◽  
Nitrogen Fertilization ◽  
Cell Wall Composition ◽  
Maize Stover

scholarly journals UDP-glucose dehydrogenases of maize: a role in cell wall pentose biosynthesis

2005 ◽  
Vol 391 (2) ◽  
pp. 409-415 ◽  
Author(s):  
Anna Kärkönen ◽  
Alain Murigneux ◽  
Jean-Pierre Martinant ◽  
Elodie Pepey ◽  
Christophe Tatout ◽  
...  
Keyword(s):  
Cell Wall ◽  
Sequence Similarity ◽  
Glucose Dehydrogenase ◽  
Soya Bean ◽  
Amino Acid Sequences ◽  
Cell Wall Polysaccharide ◽  
Polysaccharide Biosynthesis ◽  
Polysaccharide Synthesis ◽  
Ethanol Dehydrogenase ◽  
Adh Activity

UDPGDH (UDP-D-glucose dehydrogenase) oxidizes UDP-Glc (UDP-D-glucose) to UDP-GlcA (UDP-D-glucuronate), the precursor of UDP-D-xylose and UDP-L-arabinose, major cell wall polysaccharide precursors. Maize (Zea mays L.) has at least two putative UDPGDH genes (A and B), according to sequence similarity to a soya bean UDPGDH gene. The predicted maize amino acid sequences have 95% similarity to that of soya bean. Maize mutants with a Mu-element insertion in UDPGDH-A or UDPGDH-B were isolated (udpgdh-A1 and udpgdh-B1 respectively) and studied for changes in wall polysaccharide biosynthesis. The udpgdh-A1 and udpgdh-B1 homozygotes showed no visible phenotype but exhibited 90 and 60–70% less UDPGDH activity respectively than wild-types in a radiochemical assay with 30 μM UDP-glucose. Ethanol dehydrogenase (ADH) activity varied independently of UDPGDH activity, supporting the hypothesis that ADH and UDPGDH activities are due to different enzymes in maize. When extracts from wild-types and udpgdh-A1 homozygotes were assayed with increasing concentrations of UDP-Glc, at least two isoforms of UDPGDH were detected, having Km values of approx. 380 and 950 μM for UDP-Glc. Leaf and stem non-cellulosic polysaccharides had lower Ara/Gal and Xyl/Gal ratios in udpgdh-A1 homozygotes than in wild-types, whereas udpgdh-B1 homozygotes exhibited more variability among individual plants, suggesting that UDPGDH-A activity has a more important role than UDPGDH-B in UDP-GlcA synthesis. The fact that mutation of a UDPGDH gene interferes with polysaccharide synthesis suggests a greater importance for the sugar nucleotide oxidation pathway than for the myo-inositol pathway in UDP-GlcA biosynthesis during post-germinative growth of maize.

Changes in cell wall composition associated with maturation in the gymnosperm Araucaria angustifolia

2006 ◽  
Vol 38 (3-5) ◽  
pp. 180-190 ◽  
Author(s):  
Renato Bochicchio ◽  
Carmen L.O. Petkowicz ◽  
Iedo Alquini ◽  
Ana P. Busato ◽  
Fany Reicher
Keyword(s):  
Cell Wall ◽  
Cell Wall Composition ◽  
Araucaria Angustifolia

Cell-wall composition and viomycin resistance in Rhizobium meliloti

1972 ◽  
Vol 18 (7) ◽  
pp. 1168-1170 ◽  
Author(s):  
C. R. MacKenzie ◽  
D. C. Jordan
Keyword(s):  
Cell Wall ◽  
Cell Surface ◽  
Rhizobium Meliloti ◽  
Cell Wall Composition ◽  
Surface Layers ◽  
Mechanism Of Resistance ◽  
Resistant Cells

Mutation to viomycin-resistance in Rhizobium meliloti R21 resulted in an accumulation of phosphatidylcholine and phosphatidylethanolamine in the cell wall. Resistance to viomycin decreased when the excess lipid was removed by EDTA or when its synthesis was prevented by growth of normally resistant cells at 40 °C. Microelectrophoretic data showed binding of viomycin to the cell surface and it is proposed that the mechanism of resistance to viomycin is an immobilization of the antibiotic in the surface layers of the cell as a result of combination with phospholipid.

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