scholarly journals The Heterotrophic Dinoflagellate Crypthecodinium cohnii Defines a Model Genetic System To Investigate Cytoplasmic Starch Synthesis

2008 ◽  
Vol 7 (5) ◽  
pp. 872-880 ◽  
Author(s):  
Philippe Deschamps ◽  
Delphine Guillebeault ◽  
Jimi Devassine ◽  
David Dauvillée ◽  
Sophie Haebel ◽  
...  
Keyword(s):  
Starch Synthesis ◽  
Length Distribution ◽  
Genetic System ◽  
Soluble Starch ◽  
Land Plant ◽  
Heterotrophic Dinoflagellate ◽  
Chain Length Distribution ◽  
Crypthecodinium Cohnii ◽  
A Chain

ABSTRACT The nature of the cytoplasmic pathway of starch biosynthesis was investigated in the model heterotrophic dinoflagellate Crypthecodinium cohnii. The storage polysaccharide granules were shown to be composed of both amylose and amylopectin fractions with a chain length distribution and crystalline organization very similar to those of green algae and land plant starch. Preliminary characterization of the starch pathway demonstrated that C. cohnii contains multiple forms of soluble starch synthases and one major 110-kDa granule-bound starch synthase. All purified enzymes displayed a marked substrate preference for UDP-glucose. At variance with most other microorganisms, the accumulation of starch in the dinoflagellate occurs during early and mid-log phase, with little or no synthesis witnessed when approaching stationary phase. In order to establish a genetic system allowing the study of cytoplasmic starch metabolism in eukaryotes, we describe the isolation of marker mutations and the successful selection of random recombinant populations after homothallic crosses.

scholarly journals Pathway of Cytosolic Starch Synthesis in the Model Glaucophyte Cyanophora paradoxa

2007 ◽  
Vol 7 (2) ◽  
pp. 247-257 ◽  
Author(s):  
Charlotte Plancke ◽  
Christophe Colleoni ◽  
Philippe Deschamps ◽  
David Dauvillée ◽  
Yasunori Nakamura ◽  
...  
Keyword(s):  
Starch Synthesis ◽  
Length Distribution ◽  
Soluble Starch ◽  
Land Plant ◽  
Starch Synthase ◽  
Cyanophora Paradoxa ◽  
Chain Length Distribution ◽  
Photosynthetic Eukaryotes ◽  
A Chain

ABSTRACT The nature of the cytoplasmic pathway of starch biosynthesis was investigated in the model glaucophyte Cyanophora paradoxa. The storage polysaccharide granules are shown to be composed of both amylose and amylopectin fractions, with a chain length distribution and crystalline organization similar to those of green algae and land plant starch. A preliminary characterization of the starch pathway demonstrates that Cyanophora paradoxa contains several UDP-glucose-utilizing soluble starch synthase activities related to those of the Rhodophyceae. In addition, Cyanophora paradoxa synthesizes amylose with a granule-bound starch synthase displaying a preference for UDP-glucose. A debranching enzyme of isoamylase specificity and multiple starch phosphorylases also are evidenced in the model glaucophyte. The picture emerging from our biochemical and molecular characterizations consists of the presence of a UDP-glucose-based pathway similar to that recently proposed for the red algae, the cryptophytes, and the alveolates. The correlative presence of isoamylase and starch among photosynthetic eukaryotes is discussed.

Evidence for a mevalonate shunt in a tracheophyte

1985 ◽  
Vol 225 (1241) ◽  
pp. 425-444 ◽  
Keyword(s):  
Chain Length ◽  
Length Distribution ◽  
Specific Inhibitor ◽  
Leaf Tissue ◽  
Acetate Incorporation ◽  
Wheat Seedlings ◽  
Chain Length Distribution ◽  
A Chain ◽  
Coa Reductase ◽  
A Minor

Primary leaf tissue from light and dark grown wheat seedlings incubated with [2- 14 C]acetate and [2- 3 H]mevalonolactone (MVA) synthesized doubly labelled sterols and long chain fatty alcohols (LCFA). While [2- 3 H]MVA was incorporated into LCFA as efficiently as into sterols, [5- 3 H]MVA was metabolized only to sterols. Mevinolin, a specific inhibitor of HMG–CoA reductase, completely inhibited [2- 14 C]acetate incorporation into sterols but it did not completely prevent [2- 3 H]MVA from being incorporated into LCFA. In the presence and absence of mevinolin, 3 H in the purified LCFA was found associated primarily with C 22 , C 24 , and C 26 (components isolated from the subcellular membranes), while 14 C was present additionally in C 28 (the major LCFA isolated from the epicuticular wax). Substantial 14 C and 3 H was incorporated into the membrane-bound 24-desalkyl and 24-alkylsterols with no loss of label associated with increasing the side chain length, that is, by alkylation at C 24 . The results demonstrate for the first time that: (i) the MVA shunt operates in a tracheophyte; (ii) preferential utilization of acetate, formed by the shunt and presumably compartmentalized, may exist in wheat for the synthesis of LCFA having a chain length distribution more suitable for membrane than wax construction; and (iii) the MVA shunt is not a minor vestigial lipid pathway but may, under certain physiological and developmental conditions, represent a pathway for routing isopentenyl pyrophosphate C-atoms away from their inclusion into the sterol pathway. Photosynthesis had no apparent effect on shunt activity.

Molecular Characterization of Iron-Containing Superoxide Dismutases in the Heterotrophic Dinoflagellate Crypthecodinium cohnii

Protist ◽  
2008 ◽  
Vol 159 (2) ◽  
pp. 223-238 ◽  
Author(s):  
Fabienne Dufernez ◽  
Evelyne Derelle ◽  
Christophe Noël ◽  
Giovanna Sanciu ◽  
Cléa Mantini ◽  
...  
Keyword(s):  
Molecular Characterization ◽  
Superoxide Dismutases ◽  
Heterotrophic Dinoflagellate ◽  
Crypthecodinium Cohnii

scholarly journals Effects of Starch Synthesis-Related Genes Polymorphism on Quality of Glutinous Rice

2021 ◽  
Vol 12 ◽  
Author(s):  
Ouling Zhang ◽  
Cheng Liang ◽  
Bowen Yang ◽  
Hui You ◽  
Liang Xu ◽  
...  
Keyword(s):  
Thermal Properties ◽  
Starch Synthesis ◽  
Genetic System ◽  
Genetic Network ◽  
Soluble Starch ◽  
Rice Quality ◽  
Starch Properties ◽  
Glutinous Rice ◽  
Crucial Information ◽  
Pasting Temperature

Glutinous rice (Oryza sativa L.) quality includes thermal properties, retrogradation and pasting viscosity properties, and so on, which have little or no amylose. However, the genetic network regulation of different quality indices has not been systematically studied. The aim was to investigate the relationship between starch synthesis-related genes (SSRGs) and the physicochemical properties of glutinous rice by targeted-gene association analysis (TGAS). The genotypes of 17 SSRGs were analyzed using 46 gene-specific molecular markers in 63 glutinous rice accessions. TGAS and gene interactions analysis indicated that soluble starch synthase (SS) IIa, SSI, starch branching enzyme (BE) IIa, and pullulanase (PUL) had significant genetic effects on glutinous rice quality. SSI and SSIIa were the major genes that regulated thermal properties and retrogradation properties (RP). PUL was central in the regulation of gel consistency (GC), and it participated in the regulation of pasting viscosity parameters (PVP) except for the pasting time and the pasting temperature. BEIIb, ISA1, SSIVb, BEIIa, SSIVa, and their interactions with SSIIa regulated gelatinization temperature (GT) and PVP. The starch properties of glutinous rice are mainly controlled by SSIIa, SSI, PUL, and their interactions, but SSIIa is central among them. These findings indicate that starch properties in glutinous rice have a complex genetic system. It provides crucial information for promoting glutinous rice quality.

Expression of bacterial starch-binding domains in Arabidopsis increases starch granule size

2006 ◽  
Vol 33 (3) ◽  
pp. 257 ◽  
Author(s):  
Crispin A. Howitt ◽  
Sadequr Rahman ◽  
Matthew K. Morell
Keyword(s):  
Starch Granule ◽  
Starch Content ◽  
Starch Synthesis ◽  
Length Distribution ◽  
Renewable Resource ◽  
Granule Size ◽  
Parental Line ◽  
In Planta ◽  
Chain Length Distribution ◽  
Binding Domains

Starch is a readily renewable resource that is very widely used for food and industrial purposes; however, greater variation in the functional properties of starch would further extend the use of this biodegradable polymer. Genetic engineering may provide a way to produce designer starches that have the desired properties. Starch-binding domains (SBD) from bacterial enzymes that catabolise starches have the ability to bind two helices of starch and thus have the potential to crosslink starch and / or to be used as anchors for other enzymes that can modify starch properties. In a first step towards novel modification of starch we have investigated the effect of expressing SBDs, singly and in tandem, in planta, and targeting them to the chloroplast in the model plant Arabidopsis thaliana (L.) Heynh. Transgenic plants that contained the SBD from the cyclomaltodextrin glucanotransferase (CGTase) of Thermoanaerobacterium thermosulfurigenes in the chloroplast were produced in both the wild type and the starch excess mutant (sex 1-1) backgrounds. Analysis of starch isolated from the chloroplasts of these lines revealed no significant changes in the amylose : amylopectin ratio, the chain-length distribution of debranched amylopectin or the gelatinisation temperature when compared to the parental line. However, significant changes were observed in the starch granule size with the plants expressing the construct having larger granules. The effect was more pronounced in the sex 1-1 background, and expression of two starch-binding domains linked in tandem had an even greater effect. Despite the starch granules being larger in lines expressing the starch-binding domain, no difference was seen in the starch content of the leaves when compared to parental lines. As the presence of the SBDs in the starch granule only altered granule size, and not other granule properties, they may provide an ideal anchor for targeting starch-modifying enzymes to the site of starch synthesis. This will allow the development of novel modifications of starch during synthesis.

scholarly journals Competition between Granule Bound Starch Synthase and Starch Branching Enzyme in Starch Biosynthesis

Rice ◽  
2019 ◽  
Vol 12 (1) ◽  
Author(s):  
Huaxin Han ◽  
Chuantian Yang ◽  
Jihui Zhu ◽  
Lixia Zhang ◽  
Yeming Bai ◽  
...  
Keyword(s):  
Functional Properties ◽  
Length Distribution ◽  
Soluble Starch ◽  
Starch Biosynthesis ◽  
Starch Synthase ◽  
Size Exclusion ◽  
Rice Starch ◽  
Rice Varieties ◽  
Chain Length Distribution ◽  
Granule Bound Starch Synthase

Abstract Background Starch branching enzymes (SBE) and granule-bound starch synthase (GBSS) are two important enzymes for starch biosynthesis. SBE mainly contributes to the formation of side branches, and GBSS mainly contributes for the synthesis of amylose molecules. However, there are still gaps in the understanding of possible interactions between SBE and GBSS. Results Nineteen natural rice varieties with amylose contents up to 28% were used. The molecular structure, in the form of the chain-length distribution (CLDs, the distribution of the number of monomer units in each branch) was measured after enzymatic debranching, using fluorophore-assisted carbohydrate electrophoresis for amylopectin and size- exclusion chromatography for amylose. The resulting distributions were fitted to two mathematical models based on the underlying biosynthetic processes, which express the CLDs in terms of parameters reflecting relevant enzyme activities. Conclusions Finding statistically valid correlations between the values of these parameters showed that GBSSI and SBEI compete for substrates during rice starch biosynthesis, and synthesis of amylose short chains involves several enzymes including GBSSI, SBE and SSS (soluble starch synthase). Since the amylose CLD is important for a number of functional properties such as digestion rate, this knowledge is potentially useful for developing varieties with improved functional properties.

scholarly journals PII1: a protein involved in starch initiation that determines granule number and size in Arabidopsis chloroplast

2018 ◽  
Author(s):  
Camille Vandromme ◽  
Corentin Spriet ◽  
David Dauvillée ◽  
Adeline Courseaux ◽  
Jean-Luc Putaux ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Growth Rates ◽  
Starch Granule ◽  
Length Distribution ◽  
Soluble Starch ◽  
Starch Granules ◽  
Wild Type ◽  
Granule Formation ◽  
Chain Length Distribution ◽  
Priming Process

AbstractThe initiation of starch granule formation is still poorly understood. However, soluble starch synthase 4 (SS4) appears to be a major component of this process since it is required to synthetize the correct number of starch granules in the chloroplasts of Arabidopsis thaliana plants. A yeast-2-hybrid screen allowed the identification of several putative SS4 interacting partners. We identified the product of At4g32190 locus as a chloroplast-targeted PROTEIN INVOLVED IN STARCH INITIATION (named PII1). Arabidopsis mutants devoid of PII1 display an alteration of starch initiation process and accumulate, on average, one starch granule per plastid instead of the 5 to 7 granules found in plastids of wild-type plants. These granules are larger than in wild type and they remain flat and lenticular. pii1 mutants display wild-type growth rates and accumulate standard starch amounts. Moreover, starch characteristics, such as amylopectin chain length distribution, remain unchanged. Our results reveal the involvement of PII1 in starch priming process in Arabidopsis leaves through interaction with SS4.

scholarly journals Increased Glycan Chain Length Distribution and Decreased Susceptibility to Moenomycin in a Vancomycin-Resistant Staphylococcus aureus Mutant

2002 ◽  
Vol 46 (1) ◽  
pp. 75-81 ◽  
Author(s):  
Hitoshi Komatsuzawa ◽  
Kouji Ohta ◽  
Sakuo Yamada ◽  
Kerstin Ehlert ◽  
Harald Labischinski ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Chain Length ◽  
Length Distribution ◽  
Reversed Phase ◽  
Chain Length Distribution ◽  
Penicillin Binding Proteins ◽  
Glycan Chain ◽  
Peptidoglycan Hydrolases ◽  
Vancomycin Resistant

ABSTRACT A vancomycin-resistant Staphylococcus aureus mutant, COL-VR1 (MIC, 16 μg/ml), was isolated from methicillin-resistant S. aureus COL by exposure to vancomycin. COL-VR1 also showed decreased susceptibility to teicoplanin (8-fold), methicillin (2-fold), macarbomycin (8-fold), and moenomycin (16-fold). Macarbomycin and moenomycin are thought to directly inhibit transglycosylase activity. Characterization of the mutant revealed a thickened cell wall and suppression of penicillin-induced lysis, although the amounts of the five penicillin-binding proteins (PBPs 1, 2, 3, 4, and 2′) and the profiles of peptidoglycan hydrolases were not altered. Analysis of muropeptide profile and glycan chain length distribution by reversed-phase high-pressure liquid chromatography revealed slightly decreased peptide cross-linking and an increased average glycan chain length compared to those of the parent. These results together suggest that a transglycosylase activity was enhanced in the mutant. This may represent a novel mechanism of glycopeptide resistance in S. aureus.

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