Elucidating carbohydrate metabolism in Euglena gracilis: Reverse genetics-based evaluation of genes coding for enzymes linked to paramylon accumulation.
Biochimie
; 184: 125-131, 2021 May.
Article
em En
| MEDLINE
| ID: mdl-33675853
ABSTRACT
Euglena gracilis is a eukaryotic single-celled and photosynthetic organism grouped under the kingdom Protista. This phytoflagellate can accumulate the carbon photoassimilate as a linear ß-1,3-glucan chain called paramylon. This storage polysaccharide can undergo degradation to provide glucose units to obtain ATP and reducing power both in aerobic and anaerobic growth conditions. Our group has recently characterized an essential enzyme for accumulating the polysaccharide, the UDP-glucose pyrophosphorylase (Biochimie vol 154, 2018, 176-186), which catalyzes the synthesis of UDP-glucose (the substrate for paramylon synthase). Additionally, the identification of nucleotide sequences coding for putative UDP-sugar pyrophosphorylases suggests the occurrence of an alternative source of UDP-glucose. In this study, we demonstrate the active involvement of both pyrophosphorylases in paramylon accumulation. Using techniques of single and combined knockdown of transcripts coding for these proteins, we evidenced a substantial decrease in the polysaccharide synthesis from 39 ± 7 µg/106 cells determined in the control at day 21st of growth. Thus, the paramylon accumulation in Euglena gracilis cells decreased by 60% and 30% after a single knockdown of the expression of genes coding for UDP-glucose pyrophosphorylase and UDP-sugar pyrophosphorylase, respectively. Besides, the combined knockdown of both genes resulted in a ca. 65% reduction in the level of the storage polysaccharide. Our findings indicate the existence of a physiological dependence between paramylon accumulation and the partitioning of sugar nucleotides into other metabolic routes, including the Leloir pathway's functionality in Euglena gracilis.
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Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Metabolismo dos Carboidratos
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Euglena gracilis
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Genética Reversa
Tipo de estudo:
Prognostic_studies
Idioma:
En
Revista:
Biochimie
Ano de publicação:
2021
Tipo de documento:
Article
País de afiliação:
Argentina