Molecular cloning and characterization of Dbr1, a 2-alkenal reductase from Artemisia annuaThe nucleotide sequence reported in this article has been deposited in the GenBank database under accession No. FJ750460.This paper is one of a selection of papers published in a  Special Issue from the National Research Council of Canada – Plant Biotechnology Institute.

The molecular genetics of carbon–carbon double bond reduction in the plant Artemisia annua L. was studied. Expressed sequence tags from this plant were investigated for sequences with similarity to known double-bond reductases. This resulted in the isolation of a cDNA, corresponding to the gene A. annua Dbr1 (Double bond reductase1), encoding a member of the medium chain dehydrogenase/reductase protein superfamily with sequence similarity to tobacco allyl alcohol dehydrogenase. Recombinant A. annua Dbr1 protein was purified from Escherischia coli and shown to catalyze the reduction of the carbon–carbon double bond of 2-alkenals. This activity included the reduction of the double bond at C11–C13 in the artemisinin precursor artemisinic aldehyde, albeit with unnatural stereochemistry. The substrate specificity, product stereochemistry, and expression pattern of A. annua Dbr1 point to its involvement in planta in the detoxification of 2-alkenals, which may be generated under oxidative stress conditions.

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The Characterization of Chitosan Nanoparticles by Raman Spectroscopy

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.665.367 ◽

2014 ◽

Vol 665 ◽

pp. 367-370 ◽

Cited By ~ 10

Author(s):

Xiao Dan Ren ◽

Qing Shan Liu ◽

Hui Feng ◽

Xiao Ying Yin

Keyword(s):

Raman Spectroscopy ◽

Double Bond ◽

Chitosan Nanoparticles ◽

Carbon Double Bond

To study the performance of chitosan nanoparticles systematically, we characterized MMA, chitosan and synthesized chitosan nanoparticles by Raman spectroscopy. Through analyzing the characteristic peaks of each substance, we found MMA grafted chitosan by opening its carbon-carbon double bond. So Raman spectroscopy is a very effective way in terms of the characterization of nanomaterials .

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Silyl-substituted α,β-Unsaturated Ketones from the Reaction of Silylvinylmetallic Reagents with Acid Anhydrides

Canadian Journal of Chemistry ◽

10.1139/v73-302 ◽

1973 ◽

Vol 51 (12) ◽

pp. 2024-2032 ◽

Cited By ~ 35

Author(s):

A. G. Brook ◽

J. M. Duff

Keyword(s):

Double Bond ◽

Low Temperatures ◽

Silyl Group ◽

Unsaturated Ketones ◽

Carbon Double Bond ◽

Benzoic Anhydride ◽

Acid Anhydrides ◽

By Products

The reactions of a series of silyl-substituted vinylmetallic reagents with acetic and benzoic anhydride have been investigated as a general route to α,β-unsaturated ketones having a silyl group attached to the carbon–carbon double bond. The reaction has been found to be generally applicable for acetyl derivatives provided low temperatures are used but the reaction with benzoic anhydride gives poorer results. The i.r. and u.v. spectra of the ketones are discussed. The characterization of novel 1,4-dienes obtained as by-products in the syntheses is also described.

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A mutant deficient in S-adenosylhomocysteine hydrolase in Arabidopsis shows defects in root-hair developmentThis paper is one of a selection of papers published in a Special Issue from the National Research Council of Canada – Plant Biotechnology Institute.

Botany ◽

10.1139/b08-124 ◽

2009 ◽

Vol 87 (6) ◽

pp. 571-584 ◽

Cited By ~ 7

Author(s):

Xianzhong Wu ◽

Fengling Li ◽

Allan Kolenovsky ◽

Allan Caplan ◽

Yuhai Cui ◽

...

Keyword(s):

Root Hair ◽

National Research Council ◽

Plant Biotechnology ◽

Adenosylhomocysteine Hydrolase ◽

Root Hair Development ◽

Dna Insertion ◽

Visual Assay ◽

Delayed Germination ◽

Arabidopsis Mutant

Root-hair development is a process involving the interplay between genetic, hormonal, and environmental factors. An Arabidopsis mutant, referred to as sahh1, was initially recovered from a screen for delayed germination. Molecular characterization of the sahh1 mutant revealed that it contained a T-DNA insertion 82 bp 5′ to the coding sequence of S-adenosylhomocysteine hydrolase 1 (SAHH1, At4g13940), resulting in the reduction of SAHH1 expression. The resulting reduction in expression of SAHH1 produced plants with short, hairless roots, delayed germination, and slow growth. All of these phenotypes were restored to normal by complementing the sahh1 mutant with a full length cDNA. In plants, SAHH1 converts S-adenosylhomocysteine to homocysteine in the activated methyl cycle, and is a precursor for methionine and S-adenosylmethionine. Using the root hairless phenotype of the sahh1 mutant as a visual assay, the effects of SAHH1 deficiency on the synthesis of homocysteine, S-adenosylmethionine, 1-cyclopropane-1-carboxylic acid, and spermidine were investigated.

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Localization, induction and characterization of a novel carbon–carbon double bond reductase fromAspergillus versicolor

Biocatalysis and Biotransformation ◽

10.3109/10242421003753787 ◽

2010 ◽

Vol 28 (3) ◽

pp. 185-191 ◽

Cited By ~ 4

Author(s):

Hong Guan ◽

Song You ◽

Xu Wang ◽

Li Yang

Keyword(s):

Double Bond ◽

Carbon Double Bond ◽

Double Bond Reductase

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Carbon-carbon double-bond formation in the intermolecular acetonitrile reductive coupling promoted by a mononuclear titanium(II) compound. Preparation and characterization of two titanium(IV) imido derivatives

Inorganic Chemistry ◽

10.1021/ic00025a036 ◽

1991 ◽

Vol 30 (25) ◽

pp. 4863-4866 ◽

Cited By ~ 45

Author(s):

Robbert. Duchateau ◽

Antony J. Williams ◽

Sandro. Gambarotta ◽

Michael Y. Chiang

Keyword(s):

Double Bond ◽

Bond Formation ◽

Reductive Coupling ◽

Carbon Double Bond

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Over-expression of α-galactosidase in pea seeds to reduce raffinose oligosaccharide contentThis paper is one of a selection of papers published in a Special Issue from the National Research Council of Canada – Plant Biotechnology Institute.

Botany ◽

10.1139/b09-020 ◽

2009 ◽

Vol 87 (6) ◽

pp. 526-532 ◽

Cited By ~ 9

Author(s):

Patricia L. Polowick ◽

David S. Baliski ◽

Cheryl Bock ◽

Heather Ray ◽

Fawzy Georges

Keyword(s):

Intestinal Flora ◽

National Research Council ◽

Plant Biotechnology ◽

Single Copy ◽

Over Expression ◽

Transgenic Lines ◽

Pea Seeds ◽

Plant Families ◽

Coffea Arabica L ◽

Selection Of

The raffinose family of oligosaccharides (RFO) is a series of complex carbohydrates stored in seeds of many plant families, especially in legumes. The digestive system of nonruminant animals, including that of humans, cannot break down all of the chemical bonds in these carbohydrates; therefore, catabolism is achieved anaerobically by intestinal flora. The resulting digestive problems reduce acceptance and limit the widespread consumption of these otherwise nutritious seeds. To demonstrate a solution to this problem, transgenic lines of pea ( Pisum sativum L.) expressing the α-galactosidase gene from coffee ( Coffea arabica L.) were developed. Plants with a single copy of the inserted gene were selected, and two of these lines showed significant reductions of up to 40% in oligosaccharide content (raffinose, stachyose). Quantitative RT-PCR confirmed the presence of the α-galactosidase RNA in both leaves and cotyledons. Sugars were analyzed using whole seeds or only a portion of a seed; in the latter case, germination rates for each of the seeds analyzed were determined. The reduced raffinose contents did not affect germination rates, which remained very high (96%). The relative oligosaccharide contents of tissues within a seed also were determined; these were highest in the embryo axis, lower in the cotyledon and lowest in the seed coat.

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Molecular cloning of an aldehyde dehydrogenase implicated in artemisinin biosynthesis in Artemisia annuaThis paper is one of a selection of papers published in a Special Issue from the National Research Council of Canada – Plant Biotechnology Institute.

Botany ◽

10.1139/b09-032 ◽

2009 ◽

Vol 87 (6) ◽

pp. 635-642 ◽

Cited By ~ 151

Author(s):

Keat H. Teoh ◽

Devin R. Polichuk ◽

Darwin W. Reed ◽

Patrick S. Covello

Keyword(s):

Aldehyde Dehydrogenase ◽

Expressed Sequence Tag ◽

Artemisia Annua ◽

Molecular Genetic ◽

National Research Council ◽

Plant Biotechnology ◽

Limited Range ◽

Molecular Genetic Data ◽

Aldehyde Oxidation ◽

Artemisinin Biosynthesis

Limitations in the supply of the antimalarial compound artemisinin from Artemisia annua L. have led to an interest in understanding its biosynthesis and enhancing its production. Recent biochemical and molecular genetic data have implicated dihydroartemisinic aldehyde as a precursor to the corresponding acid, which is then converted to artemisinin. Thus, it is important to understand the enzyme or enzymes involved in dihydroartemisinic aldehyde oxidation. Given its activity on artemisinic aldehyde, the cytochrome P450 CYP71AV1 was investigated for its ability to oxidize dihydroartemisinic aldehyde. However, no net activity was detected. In a search for alternative enzymes that could catalyze the oxidation, an expressed sequence tag (EST) collection from A. annua was investigated for relevant cDNAs. This led to the isolation of a full-length cDNA encoding an aldehyde dehydrogenase homologue, named Aldh1, which is highly expressed in trichomes. Expression of the cDNA in E. coli and characterization of the purified recombinant enzyme revealed that the gene product catalyses the NAD(P)-dependent oxidation of the putative artemisinin precursors, artemisinic and dihydroartemsinic aldehydes, and a limited range of other aldehydes. The observed enzyme activity of Aldh1 and the expression pattern of the corresponding gene suggest a role in artemisinin biosynthesis in the glandular secretory trichomes of A. annua.

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Physical and electrochemical characterization of ionic liquids based on quaternary phosphonium cations containing a carbon–carbon double bond

Electrochimica Acta ◽

10.1016/j.electacta.2011.01.023 ◽

2011 ◽

Vol 56 (11) ◽

pp. 4351-4355 ◽

Cited By ~ 38

Author(s):

Katsuhiko Tsunashima ◽

Yasushi Ono ◽

Masashi Sugiya

Keyword(s):

Ionic Liquids ◽

Double Bond ◽

Electrochemical Characterization ◽

Carbon Double Bond ◽

Phosphonium Cations

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Adaptive epigenetic memory of ancestral temperature regime in Arabidopsis thalianaThis paper is one of a selection of papers published in a Special Issue from the National Research Council of Canada – Plant Biotechnology Institute.

Botany ◽

10.1139/b09-030 ◽

2009 ◽

Vol 87 (6) ◽

pp. 650-657 ◽

Cited By ~ 127

Author(s):

C. A. Whittle ◽

S. P. Otto ◽

M. O. Johnston ◽

J. E. Krochko

Keyword(s):

Temperature Regime ◽

National Research Council ◽

Plant Biotechnology ◽

Environmental Parameters ◽

Adaptive Responses ◽

Temperature Regimes ◽

Heat Treated ◽

Epigenetic Phenomenon ◽

Selection Of ◽

Classical Genetics

Although certain acquired nongenetic (i.e., epigenetic) traits are known to be heritable in plants, little is known currently about whether environmental parameters can induce adaptive epigenetic responses in plants and whether such effects can persist through generations. We used an experimental design based on classical genetics principles to assess whether plants respond to the environmental conditions of their ancestors in an adaptive epigenetic manner. An extensive examination of genetically identical Arabidopsis thaliana (L.) Heynh lines exposed to mild heat (30 °C) or cold (16 °C) treatments in the parental and F1 generations revealed that the prior elevated temperature regime lead to a greater than fivefold improvement in fitness (seed production per individual) for plants exposed to heat in a later generation (F3). The heat-specific fitness improvements among F3 plants were observed even though the heat-treated parental and F1 generations were followed by a generation grown at a normal temperature (F2) and point towards a temperature-induced adaptive epigenetic phenomenon. No such adaptive responses were detected for cold-treated plants, indicating that there are distinctive biological processes inherent to these two temperature regimes. Overall, the data are consistent with the existence of an environmentally induced epigenetic and heritable adaptive response in plants.

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