scholarly journals Enhancing carbohydrate repartitioning into lipid and carotenoid by disruption of microalgae starch debranching enzyme

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Yuichi Kato ◽  
Tomoki Oyama ◽  
Kentaro Inokuma ◽  
Christopher J. Vavricka ◽  
Mami Matsuda ◽  
...  
Keyword(s):  
Lipid Accumulation ◽  
Time Course ◽  
Biofuel Production ◽  
Microalgae Cultivation ◽  
Dark Cycle ◽  
Gene Encoding ◽  
Debranching Enzyme ◽  
Carbohydrate Degradation ◽  
Starch Debranching Enzyme ◽  
Dynamic Time

AbstractLight/dark cycling is an inherent condition of outdoor microalgae cultivation, but is often unfavorable for lipid accumulation. This study aims to identify promising targets for metabolic engineering of improved lipid accumulation under outdoor conditions. Consequently, the lipid-rich mutant Chlamydomonas sp. KOR1 was developed through light/dark-conditioned screening. During dark periods with depressed CO2 fixation, KOR1 shows rapid carbohydrate degradation together with increased lipid and carotenoid contents. KOR1 was subsequently characterized with extensive mutation of the ISA1 gene encoding a starch debranching enzyme (DBE). Dynamic time-course profiling and metabolomics reveal dramatic changes in KOR1 metabolism throughout light/dark cycles. During light periods, increased flux from CO2 through glycolytic intermediates is directly observed to accompany enhanced formation of small starch-like particles, which are then efficiently repartitioned in the next dark cycle. This study demonstrates that disruption of DBE can improve biofuel production under light/dark conditions, through accelerated carbohydrate repartitioning into lipid and carotenoid.

Superoxide dismutase in the nonobese diabetic (NOD) mouse: A dynamic time-course study

Life Sciences ◽  
1995 ◽  
Vol 56 (25) ◽  
pp. 2223-2228 ◽  
Author(s):  
Gianpaolo Papaccio ◽  
Sonia Frascatore ◽  
Francesco Aurelio Pisanti ◽  
Michael V.G. Latronico ◽  
Thomas Linn
Keyword(s):  
Superoxide Dismutase ◽  
Time Course ◽  
Nod Mouse ◽  
Nonobese Diabetic ◽  
Time Course Study ◽  
Dynamic Time

Structural basis of carbohydrate binding in domain C of a type I pullulanase from Paenibacillus barengoltzii

2020 ◽  
Vol 76 (5) ◽  
pp. 447-457
Author(s):  
Ping Huang ◽  
Shiwang Wu ◽  
Shaoqing Yang ◽  
Qiaojuan Yan ◽  
Zhengqiang Jiang
Keyword(s):  
Binding Site ◽  
Binding Sites ◽  
Structural Basis ◽  
Carbohydrate Binding ◽  
Type I ◽  
Debranching Enzyme ◽  
Crystal Forms ◽  
Aromatic Residues ◽  
Starch Debranching Enzyme ◽  
Paenibacillus Barengoltzii

Pullulanase (EC 3.2.1.41) is a well known starch-debranching enzyme that catalyzes the cleavage of α-1,6-glycosidic linkages in α-glucans such as starch and pullulan. Crystal structures of a type I pullulanase from Paenibacillus barengoltzii (PbPulA) and of PbPulA in complex with maltopentaose (G5), maltohexaose (G6)/α-cyclodextrin (α-CD) and β-cyclodextrin (β-CD) were determined in order to better understand substrate binding to this enzyme. PbPulA belongs to glycoside hydrolase (GH) family 13 subfamily 14 and is composed of three domains (CBM48, A and C). Three carbohydrate-binding sites identified in PbPulA were located in CBM48, near the active site and in domain C, respectively. The binding site in CBM48 was specific for β-CD, while that in domain C has not been reported for other pullulanases. The domain C binding site had higher affinity for α-CD than for G6; a small motif (FGGEH) seemed to be one of the major determinants for carbohydrate binding in this domain. Structure-based mutations of several surface-exposed aromatic residues in CBM48 and domain C had a debilitating effect on the activity of the enzyme. These results suggest that both CBM48 and domain C play a role in binding substrates. The crystal forms described contribute to the understanding of pullulanase domain–carbohydrate interactions.

scholarly journals Purification and Molecular Genetic Characterization of ZPU1, a Pullulanase-Type Starch-Debranching Enzyme from Maize

1999 ◽  
Vol 119 (1) ◽  
pp. 255-266 ◽  
Author(s):  
Mary K. Beatty ◽  
Afroza Rahman ◽  
Heping Cao ◽  
Wendy Woodman ◽  
Michael Lee ◽  
...  
Keyword(s):  
Genetic Characterization ◽  
Molecular Genetic ◽  
Debranching Enzyme ◽  
Starch Debranching Enzyme ◽  
Molecular Genetic Characterization

Metabolic adjustments during daily torpor in the Djungarian hamster

1999 ◽  
Vol 276 (5) ◽  
pp. E896-E906 ◽  
Author(s):  
Gerhard Heldmaier ◽  
Martin Klingenspor ◽  
Martin Werneyer ◽  
Brian J. Lampi ◽  
Stephen P. J. Brooks ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
Metabolic Rate ◽  
Brown Adipose Tissue ◽  
Serum Lipids ◽  
Time Course ◽  
Gradual Change ◽  
Daily Torpor ◽  
Dark Cycle ◽  
Brown Adipose ◽  
Enzyme Changes

Djungarian hamsters ( Phodopus sungorus) acclimated to a short photoperiod (8:16-h light-dark cycle) display spontaneous daily torpor with ad libitum food availability. The time course of body temperature (Tb), metabolic rate, respiratory quotient (RQ), and substrate and enzyme changes was measured during entrance into torpor and in deep torpor. RQ, blood glucose, and serum lipids are high during the first hours of torpor but then gradually decline, suggesting that glucose is the primary fuel during the first hours of torpor, with a gradual change to lipid utilization. No major changes in enzyme activities were observed during torpor except for inactivation of the pyruvate dehydrogenase (PDH) complex in liver, brown adipose tissue, and heart muscle. PDH inactivation closely correlates with the reduction of total metabolic rate, whereas in brain, kidney, diaphragm, and skeletal muscle, PDH activity was maintained at the initial level. These findings suggest inhibition of carbohydrate oxidation in heart, brown adipose tissue, and liver during entrance into daily torpor.

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