Conversion of membrane lipid acyl groups to triacylglycerol and formation of lipid bodies upon nitrogen starvation in biofuel green algae Chlorella UTEX29.
Planta
; 238(5): 895-906, 2013 Nov.
Article
en En
| MEDLINE
| ID: mdl-23928654
ABSTRACT
Algal lipids are ideal biofuel sources. Our objective was to determine the contributors to triacylglycerol (TAG) accumulation and lipid body formation in Chlorella UTEX29 under nitrogen (N) deprivation. A fivefold increase in intracellular lipids following N starvation for 24 h confirmed the oleaginous characteristics of UTEX29. Ultrastructural studies revealed increased number of lipid bodies and decreased starch granules in N-starved cells compared to N-replete cells. Lipid bodies were observed as early as 3 h after N removal and plastids collapsed after 48 h of stress. Moreover, the identification of intracellular pyrenoids and differences in the expected nutritional requirements for Chlorella protothecoides (as UTEX29 is currently classified) led us to conduct a phylogenetic study using 18S and actin cDNA sequences. This indicated UTEX29 to be more phylogenetically related to Chlorella vulgaris. To investigate the fate of different lipids after N starvation, radiolabeling using ¹4C-acetate was used. A significant decrease in ¹4C-galactolipids and phospholipids matched the increase in ¹4C-TAG starting at 3 h of N starvation, consistent with acyl groups from structural lipids as sources for TAG under N starvation. These results have important implications for the identification of key steps controlling oil accumulation in N-starved biofuel algae and demonstrate membrane recycling during lipid body formation.
Texto completo:
1
Bases de datos:
MEDLINE
Asunto principal:
Triglicéridos
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Chlorella
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Biocombustibles
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Lípidos de la Membrana
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Nitrógeno
Tipo de estudio:
Prognostic_studies
Idioma:
En
Revista:
Planta
Año:
2013
Tipo del documento:
Article
País de afiliación:
Estados Unidos