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Sample Set Information

ID TSE1243
Title Physiological roles of the beta-substituted alanine synthase gene family in Arabidopsis.
Description The beta-substituted alanine (Ala) synthase (Bsas) family in the large superfamily of pyridoxal 5'-phosphate-dependent enzymes comprises cysteine (Cys) synthase (CSase) [O-acetyl-serine (thiol) lyase] and beta-cyano-Ala synthase (CASase) in plants. Nine genomic sequences encode putative Bsas proteins in Arabidopsis thaliana. The physiological roles of these Bsas isoforms in vivo were investigated by the characterization of T-DNA insertion mutants. Analyses of gene expression, activities of CSase and CASase, and levels of Cys and glutathione in the bsas mutants indicated that cytosolic Bsas1;1, plastidic Bsas2;1, and mitochondrial Bsas2;2 play major roles in Cys biosynthesis. Cytosolic Bsas1;1 has the most dominant contribution both in leaf and root, and mitochondrial Bsas2;2 plays a significant role in root. Mitochondrial Bsas3;1 is a genuine CASase. Nontargeted metabolome analyses of knockout mutants were carried out by a combination of gas chromatography time-of-flight mass spectrometry and capillary electrophoresis time-of-flight mass spectrometry. The level of gamma-glutamyl-beta-cyano-Ala decreased in the mutant bsas3;1, indicating the crucial role of Bsas3;1 in beta-cyano-Ala metabolism in vivo.
Authors Watanabe M, Kusano M, Oikawa A, Fukushima A, Noji M, Saito K.
Reference Plant Physiol. 2008 Jan;146(1):310-20. Epub 2007 Nov 16.

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Sample Information

Title Plant Materials and Growth Conditions
Organism - Scientific Name Arabidopsis thaliana
Organism - ID NCBI taxonomy 3702
Compound - ID
Compound - Source
Preparation Arabidopsis (Arabidopsis thaliana ecotype Col-0) plants were used as the wild type in this study.
Sample Preparation Details ID SS1

Sample Preparation Details Information

Title Sample Preparation
Description Plants were cultured on germination medium (GM)-agar medium containing 1% Suc (Valvekens et al., 1988) in a growth chamber at 22°C under 16-h-light (approximately 2,500 lux)/8-h-dark cycles for 2 weeks. The leaves and roots of the plants were harvested, immediately frozen with liquid nitrogen, and stored at −80°C until use. Identical plant materials were analyzed for their gene expression, enzyme activities, and metabolite profiles.

Analytical Method Information

Method Details ID MS1
Sample Amount

Analytical Method Details Information

Instrument GC:Agilent 6890N MS:LECO Pegasus 4D MS system
Instrument Type
Ionization EI
Ion Mode Positive
Description Sixteen plants were planted on a single plate separated into fourths to minimize the differences in growth conditions. Four wild-type plants were planted on one-fourth, and four bsas mutant plants were planted on each of the remaining fourths. Five plates were replicated for each bsas mutant. Each sample was extracted with a concentration of 25 mg fresh weight of tissues per microliter of the extraction medium (methanol:chloroform:water [3:1:1; v/v/v]) by using a Retsh mixer mill MM 310 at a frequency of 30 Hz−1 for 3 min at 4°C. After centrifugation for 5 min at 15,100g, 400 μL of the supernatant of each plate were put together in accordance with each section of fourths. Four hundred microliters of the 2-mL supernatant were used for GC-TOF/MS analysis, and another 400 μL were used for CE-TOF/MS analysis.

The analysis of metabolites by GC-TOF/MS, including the derivatization step and the processing of MS data, was performed as described elsewhere (Kusano et al., 2007a, 2007b).


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