New Assay Method for Starch Branching Enzyme and Starch Synthase by the Chain-length Distribution Analysis

Synthetic polymers are mixtures of different length chains, and their chain length and chain conformation is often experimentally characterized by ensemble averages. We demonstrate that Double-Electron-Electron-Resonance (DEER) spectroscopy can reveal the chain length distribution, and chain conformation and flexibility of the individual n-mers in oligo-(9,9-dioctylfluorene) from controlled Suzuki-Miyaura Coupling Polymerization (cSMCP). The required spin-labeled chain ends were introduced efficiently via a TEMPO-substituted initiator and chain terminating agent, respectively, with an in situ catalyst system. Individual precise chain length oligomers as reference materials were obtained by a stepwise approach. Chain length distribution, chain conformation and flexibility can also be accessed within poly(fluorene) nanoparticles.

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Natural variation in rice starch synthase IIa affects enzyme and starch properties

Functional Plant Biology ◽

10.1071/fp04009 ◽

2004 ◽

Vol 31 (7) ◽

pp. 671 ◽

Cited By ~ 108

Author(s):

Takayuki Umemoto ◽

Noriaki Aoki ◽

Hongxuan Lin ◽

Yasunori Nakamura ◽

Naoyoshi Inouchi ◽

...

Keyword(s):

Amino Acid ◽

Natural Variation ◽

Oryza Sativa L ◽

Length Distribution ◽

Starch Synthase ◽

Rice Starch ◽

Nucleotide Polymorphisms ◽

Cultivated Rice ◽

Chain Length Distribution ◽

Starch Properties

The natural variation in starch synthase IIa (SSIIa) of rice (Oryza sativa L.) was characterised using near-isogenic lines (NILs). SSIIa is a candidate for the alk gene regulating the alkali disintegration of rice grains, since both genes are genetically mapped at the same position on chromosome 6 and related to starch properties. In this study, we report that the alkali-susceptible cultivar Nipponbare lacked SSIIa activity in endosperm. However, the activity was detected with NILs having the alk allele of alkali-tolerant Kasalath. SSIIa protein was present even in Nipponbare endosperm, but it was not associated with starch granules at the milky stage of endosperm. Three single-nucleotide polymorphisms (SNPs) predicting amino acid substitutions existed between the cDNA sequences of SSIIa of Nipponbare and Kasalath were genotyped with 65 rice cultivars and four wild relatives of cultivated rice. The results obtained explain the potential importance of two of the amino acid residues for starch association of rice SSIIa. An analysis of the chain-length distribution of β-limit dextrin of amylopectin showed that without SSIIa activity, the relative number of A-chains (the short chains without branches) increased and that of B1-chains (the short chains with branches) decreased. This suggests that, given the SSIIa defect, short A-chains could not reach a sufficient length for branching enzymes to act on them to produce B1-chains.

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GLC determination of chain length distribution in fatty alcohol polyethoxylates and sulfated derivatives

Journal of the American Oil Chemists Society ◽

10.1007/bf02682573 ◽

1966 ◽

Vol 43 (12) ◽

pp. 690-690 ◽

Cited By ~ 5

Author(s):

S Lee ◽

N. A. Puttnam

Keyword(s):

Chain Length ◽

Fatty Alcohol ◽

Length Distribution ◽

Chain Length Distribution

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Chain-length dependent termination in pulsed-laser polymerization, 7. The evaluation of the power-law exponentb from the chain-length distribution in the low frequency (single-pulse) limit for the reference systems styrene and methyl methacrylate in bulk at 25°C

Macromolecular Chemistry and Physics ◽

10.1002/(sici)1521-3935(19990901)200:9<2031::aid-macp2031>3.0.co;2-1 ◽

1999 ◽

Vol 200 (9) ◽

pp. 2031-2039 ◽

Cited By ~ 21

Author(s):

Oskar Friedrich Olaj ◽

Philipp Vana ◽

Andreas Kornherr ◽

Gerhard Zifferer

Keyword(s):

Methyl Methacrylate ◽

Chain Length ◽

Power Law ◽

Length Distribution ◽

Low Frequency ◽

Pulsed Laser ◽

Single Pulse ◽

Reference Systems ◽

Chain Length Distribution ◽

Pulsed Laser Polymerization

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Miniaturized Analysis of Amylopectin Chain Length Distribution by Fluorescence-Assisted Capillary Electrophoresis (FACE) down to Single Starch Granules

10.26434/chemrxiv.13568228 ◽

2021 ◽

Author(s):

amandine pruvost ◽

stanislas helle ◽

nicolas szydlowski ◽

Christian ROLANDO

Keyword(s):

Capillary Electrophoresis ◽

Chain Length ◽

Solid Phase ◽

Potato Starch ◽

Relative Proportion ◽

Length Distribution ◽

Fluorescence Analysis ◽

Starch Granules ◽

Chain Length Distribution ◽

Single Granule

In the present work, we developed a miniaturized method for determining amylopectin chain length distribution (CLD) by fluorescence-assisted capillary electrophoresis (FACE). The method relies on single granule entrapping into capillaries followed by direct starch gelatinization and amylopectin debranching on carbograph-based solid phase extraction (SPE) cartridges. Sample desalting on HypersepTM tips following APTS-labelling and the use of nanovials allowed for the fluorescence analysis of weakly diluted samples. Consequently, method sensitivity was improved by 500-fold which is compatible with the analysis of single potato starch granules. The method was implemented to determine CLD profiles of single starch granules ranging from 50 to 100 µm in diameter. In these experiments, the relative proportion of starch glucans of up to 30 degrees of polymerization (DP) could be quantified.

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Production of very-high-amylose cassava by post-transcriptional silencing of branching enzyme genes

10.1101/477414 ◽

2018 ◽

Author(s):

Wenzhi Zhou ◽

Shanshan Zhao ◽

Shutao He ◽

Qiuxiang Ma ◽

Xinlu Lu ◽

...

Keyword(s):

Amylose Content ◽

Length Distribution ◽

Constitutive Expression ◽

Raw Material ◽

Distribution Analysis ◽

Starch Granules ◽

Storage Roots ◽

Chain Length Distribution ◽

Transgenic Cassava ◽

High Amylose

AbstractHigh amylose starch, a desired raw material in the starch industry, can be produced by plants deficient in the function of branching enzymes (BEs). Here we report the production of transgenic cassava plants with starches containing up to 50% amylose due to the constitutive expression of hair-pin dsRNAs targeting the BE1 or BE2 genes. A significant decrease in BE transcripts was confirmed in these transgenic plants by quantitative real-time RT-PCR. The absence of BE1 protein in the BE1-RNAi plant lines (BE1i) and a dramatically lower level of BE2 protein in the BE2-RNAi plant lines (BE2i) were further confirmed by Western blot assays. All transgenic plant lines were grown up in the field, but with reduced biomass production of the above-ground parts and storage roots compared to wild type (WT). Considerably high amylose content in the storage roots of BE2i plant lines was achieved, though not in BE1i plant lines. Storage starch granules of BE1i and BE2i plants had similar morphology as WT, however, the size of BE1i starch granules were bigger than that of WT. Comparisons of amylograms and thermograms of all three sources of storage starches revealed dramatic changes to the pasting properties and a higher melting temperature for BE2i starches. Glucan chain length distribution analysis showed a slight increase in chains of DP>36 in BE1i lines and a dramatic increase in glucan chains between DP 10-20 and DP>40 in BE2i lines, compared to that of WT starch. Furthermore, BE2i starches displayed a B-type X-ray diffraction pattern instead of the A-type pattern found in BE1i and WT starches. Therefore, cassava BE1 and BE2 function differently in storage root starch biosynthesis; silencing of cassava BE1 or BE2 caused various changes to starch physico-chemical properties and amylopectin structure. We also report that remarkably high amylose content in cassava starch has been first obtained in transgenic cassava by silencing of BE2 expression, thus showing a high potential for future industrial utilization.

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