Taxonomic group: protista / Euglenozoa (Phylum: Euglenozoa)
 
NCBI PubMed ID: 33675853
Publication DOI: 10.1016/j.biochi.2021.02.016
Journal NLM ID: 1264604
Publisher: Paris: Editions Scientifiques Elsevier
Correspondence: S.A. Guerrero <saguerrerosantafe-conicet.gov.ar>
Institutions: Laboratorio de Enzimología Molecular, Instituto de Agrobiotecnología del Litoral (CONICET - UNL), Argentina, Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral, Argentina, Laboratorio de Biología del ARN, Instituto de Agrobiotecnología del Litoral (CONICET - UNL), Argentina, Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral, Argentina

Euglena gracilis is a eukaryotic single-celled and photosynthetic organism grouped under the kingdom Protista. This phytEuglena gracilis is a eukaryotic single-celled and photosynthetic organism grouped under the kingdom Protista. This phytoflagellate can accumulate the carbon photoassimilate as a linear β-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.

sugar nucleotide, Euglena gracilis, knockdown, reserve polysaccharide, RNAi

Structure type: homopolymer
Location inside paper: p. 125
Trivial name: glucan, β-1,3-glucan, curdlan, curdlan-type polysaccharide 13140, paramylon, curdlan, laminarin, β-glucan, curdlan, β-(1,3)-glucan, β-(1,3)-glucan, curdlan, curdlan, β-1,3-glucan, paramylon, reserve polysaccharide, b-glucan, β-1,3-D-glucan, laminaran, botryosphaeran, laminaran type β-D-glucan, latiglucan I, pachymaran, Curdlan, zymosan A, β-glucan, curdlan, laminarin, zymosan, zymosan, glucan particles, zymosan, β-(1-3)-glucan, β-(1,3)-glucan, β-(1,3)glucan, pachymaran, D-glucan (DPn)540, pachyman, laminaran, curdlan, zymosan, zymosan, β-(1,3)-glucan, zymosan A, zymosan, β-1,3-glucan, curdlan, β-1,3-glucan, curdlan, β-1,3-glucan, curdlan, pachyman, β-(1,3)-glucan, curdlan, callose, a water-insoluble β-(1→3)-glucan, fermentum β-polysaccharide, water-insoluble glucan, alkali-soluble β-glucan (PeA3), alkali-soluble polysaccharide (PCAP), callose, laminarin
Compound class: EPS, O-polysaccharide, cell wall polysaccharide, lipophosphoglycan, glycoprotein, LPG, glucan, polysaccharide, glycoside, β-glucan, β3-glucan, cell wall glucan
Contained glycoepitopes: IEDB_1397514,IEDB_142488,IEDB_146664,IEDB_153543,IEDB_158555,IEDB_161166,IEDB_2278476,IEDB_2278477,IEDB_558869,IEDB_857743,IEDB_983931,SB_192
 
Methods: SDS-PAGE, DNA techniques, kinetics assays, enzyme assay, extraction, cloning
 
NCBI Taxonomy refs (TaxIDs): 3039
Reference(s) to other database(s): GTC:G51056AN, GlycomeDB:157, CCSD:50049, CBank-STR:4225, CA-RN: 51052-65-4, GenDB:FJ3380871.1
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