Role of transamination in the mobilization of respiratory substrates in germinating seeds of castor oil plants

Popov, Vasily N.; Епринцев, А. Т.; Федорин, Д. Н.; Fomenko, O. Yu.; Igamberdiev, Abir U.

doi:10.1134/s0003683807030179

Cited by 6 publications

(3 citation statements)

References 14 publications

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“…Considerable amounts of GABA are formed in germinating seeds. A study of SSADH metabolism indicated that the mobilization of respiratory substrates during R. communis seed germination involves the GABA shunt pathway [ 43 ]. It is likely that this is the same role that SSADH plays during seed development in A. platanoides .…”

Section: Resultsmentioning

confidence: 99%

Proteomic Analysis of Embryogenesis and the Acquisition of Seed Dormancy in Norway Maple (Acer platanoides L.)

Leśniewska

Pawłowski

2014

IJMS

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The proteome of zygotic embryos of Acer platanoides L. was analyzed via high-resolution 2D-SDS-PAGE and MS/MS in order to: (1) identify significant physiological processes associated with embryo development; and (2) identify changes in the proteome of the embryo associated with the acquisition of seed dormancy. Seventeen spots were identified as associated with morphogenesis at 10 to 13 weeks after flowering (WAF). Thirty-three spots were associated with maturation of the embryo at 14 to 22 WAF. The greatest changes in protein abundance occurred at 22 WAF, when seeds become fully mature. Overall, the stage of morphogenesis was characterized by changes in the abundance of proteins (tubulins and actin) associated with the growth and development of the embryo. Enzymes related to energy supply were especially elevated, most likely due to the energy demand associated with rapid growth and cell division. The stage of maturation is crucial to the establishment of seed dormancy and is associated with a higher abundance of proteins involved in genetic information processing, energy and carbon metabolism and cellular and antioxidant processes. Results indicated that a glycine-rich RNA-binding protein and proteasome proteins may be directly involved in dormancy acquisition control, and future studies are warranted to verify this association.

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Section: Resultsmentioning

confidence: 99%

Proteomic Analysis of Embryogenesis and the Acquisition of Seed Dormancy in Norway Maple (Acer platanoides L.)

Leśniewska

Pawłowski

2014

IJMS

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“…A 2-ml aliquot of the supernatant was desalted by passing it through a Sephadex G-25 column with 10-ml bed volume, and the void volume was collected. Alanine transaminase, aspartate transaminase and succinic semialdehyde dehydrogenase were assayed essentially as described previously (Good and Muench 1992;de Sousa and Sodek 2003;Popov et al 2007). For aspartate kinase and succinic semialdehyde reductase, extraction, purification and enzymatic assay were performed essentially as described by Wang et al (2001) and Hoover et al (2007), respectively, using 2 g of callus as the starting material.…”

Section: Assays Of Amino Acid-metabolizing Enzymesmentioning

confidence: 99%

Inhibition of aconitase in citrus fruit callus results in a metabolic shift towards amino acid biosynthesis

Degu

Hatew

Nunes‐Nesi

et al. 2011

Planta

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Citrate, a major determinant of citrus fruit quality, accumulates early in fruit development and declines towards maturation. The isomerization of citrate to isocitrate, catalyzed by aconitase is a key step in acid metabolism. Inhibition of mitochondrial aconitase activity early in fruit development contributes to acid accumulation, whereas increased cytosolic activity of aconitase causes citrate decline. It was previously hypothesized that the block in mitochondrial aconitase activity, inducing acid accumulation, is caused by citramalate. Here, we investigated the effect of citramalate and of another aconitase inhibitor, oxalomalate, on aconitase activity and regulation in callus originated from juice sacs. These compounds significantly increased citrate content and reduced the enzyme's activity, while slightly inducing its protein level. Citramalate inhibited the mitochondrial, but not cytosolic form of the enzyme. Its external application to mandarin fruits resulted in inhibition of aconitase activity, with a transient increase in fruit acidity detected a few weeks later. The endogenous level of citramalate was analyzed in five citrus varieties: its pattern of accumulation challenged the notion of its action as an endogenous inhibitor of mitochondrial aconitase. Metabolite profiling of oxalomalate-treated cells showed significant increases in a few amino acids and organic acids. The activities of alanine transaminase, aspartate transaminase and aspartate kinase, as well as these of two γ-aminobutyrate (GABA)-shunt enzymes, succinic semialdehyde reductase (SSAR) and succinic semialdehyde dehydrogenase (SSAD) were significantly induced in oxalomalate-treated cells. It is suggested that the increase in citrate, caused by aconitase inhibition, induces amino acid synthesis and the GABA shunt, in accordance with the suggested fate of citrate during the acid decline stage in citrus fruit.

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“…Similarly skewed distribution of analyte ions is also observed. As shown in Figure 1b, a much higher ion intensity for the ion at m/z 104.1, likely from ␥-aminobutyric acid, one of the major amino compounds produced during germination and early seedling growth of plant [23,24], is observed not only in the cotyledon portion of garlic, as expected, but also in the left portion of the tissue where the area was ana-lyzed first during the MSI experiment. Note that the garlic tissue as well as the chicken liver tissue used in the subsequent studies merely served as the sample tissue to reveal the improved MS performance when ionic matrices were used.…”

Section: Resultsmentioning

confidence: 57%

Ionic matrix for matrix-enhanced surface-assisted laser desorption ionization mass spectrometry imaging (ME-SALDI-MSI)

Liu

2009

J. Am. Soc. Mass Spectrom.

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Matrix-enhanced surface-assisted laser desorption ionization mass spectrometry imaging (ME-SALDI MSI) has been previously demonstrated as a viable approach to improving MS imaging sensitivity. We describe here the employment of ionic matrices to replace conventional MALDI matrices as the coating layer with the aims of reducing analyte redistribution during sample preparation and improving matrix vacuum stability during imaging. In this study, CHCA/ANI (␣-cyano-4-hydroxycinnamic acid/aniline) was deposited atop tissue samples through sublimation to eliminate redistribution of analytes of interest on the tissue surface. The resulting film was visually homogeneous under an optical microscope. Excellent vacuum stability of the ionic matrix was quantitatively compared with the conventional matrix. The subsequently improved ionization efficiency of the analytes over traditional MALDI was demonstrated. The benefits of using the ionic matrix in MS imaging were apparent in the analysis of garlic tissue sections in the ME-SALDI MSI mode. To further improve imaging sensitivity, a hybrid ionization approach, matrix-enhanced SALDI (ME-SALDI), has been recently reported in which conventional matrix molecules were deposited atop a porous SALDI substrate to provide a proton-rich environment for enhanced ionization of desorbed species [6]. The porous SALDI substrate in ME-SALDI is believed to effectively reduce laser flux needed for analyte desorption; consequently few matrix ions and fragments are observed in the resulting spectra. Both characteristics are crucial for detection of low-mass species, rendering ME-SALDI an attractive solution for MS imaging (MSI) of metabolites, especially for those where imaging at high spatial resolution under a reduced laser beam size is desired. Improved MS performance over conventional MALDI and SALDI ionization methods has been demonstrated with enhanced detection sensitivity and a broadened detection mass window [6].However, an inherent challenge associated with matrix-based laser desorption ionization sources is also present in ME-SALDI for MSI applications: it is known that most conventional MALDI matrices slowly vaporize under high vacuum (10 Ϫ7 ϳ10 Ϫ8 Torr) due to their low sublimation points. The loss of materials becomes more severe when the matrix is amorphous-a common form observed when the matrix is deposited by sublimation in a solvent-free fashion. While the loss of matrix under vacuum does not necessarily impose a problem in MALDI profiling experiments where most measurements occur in seconds, it cannot be ignored during MS imaging experiments because of extended interrogation time and the preferred solvent-free approach for matrix deposition [7]. For example, for a commercial MALDI-TOF instrument equipped with a 20-Hz N 2 laser, approximately 720 pixels can be imaged in 1 h when 100 laser shots are averaged per pixel, which translates to ϳ55.6 h of instrument time to examine a 1-cm 2 tissue section with spatial resolution of 50 m, not counting the time spent for translational s...

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Role of transamination in the mobilization of respiratory substrates in germinating seeds of castor oil plants

Cited by 6 publications

References 14 publications

Proteomic Analysis of Embryogenesis and the Acquisition of Seed Dormancy in Norway Maple (Acer platanoides L.)

Proteomic Analysis of Embryogenesis and the Acquisition of Seed Dormancy in Norway Maple (Acer platanoides L.)

Inhibition of aconitase in citrus fruit callus results in a metabolic shift towards amino acid biosynthesis

Ionic matrix for matrix-enhanced surface-assisted laser desorption ionization mass spectrometry imaging (ME-SALDI-MSI)

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