Co-ordinate regulation of genes involved in storage lipid mobilization in Arabidopsis thaliana

Molecular genetic approaches in the model plant Arabidopsis thaliana (ColO) are shedding new light on the role and control of the pathways associated with the mobilization of lipid reserves during oilseed germination and post-germinative growth. Numerous independent studies have reported on the expression of individual genes encoding enzymes from the three major pathways: β-oxidation, the glyoxylate cycle and gluconeogenesis. However, a single comprehensive study of representative genes and enzymes from the different pathways in a single plant species has not been done. Here we present results from Arabidopsis that demonstrate the co-ordinate regulation of gene expression and enzyme activities for the acyl-CoA oxidase- and 3-ketoacyl-CoA thiolasemediated steps of β-oxidation, the isocitrate lyase and malate synthase steps of the glyoxylate cycle and the phosphoenolpyruvate carboxykinase step of gluconeogenesis. The mRNA abundance and enzyme activities increase to a peak at stage 2, 48 h after the onset of seed germination, and decline thereafter either to undetectable levels (for malate synthase and isocitrate lyase) or low basal levels (for the genes of β-oxidation and gluconeogenesis). The co-ordinate induction of all these genes at the onset of germination raises the possibility that a global regulatory mechanism operates to induce the expression of genes associated with the mobilization of storage reserves during the heterotrophic growth period.

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Effect of Leaf Senescence on Glyoxylate Cycle Enzyme Activities

Functional Plant Biology ◽

10.1071/pp9920723 ◽

1992 ◽

Vol 19 (6) ◽

pp. 723 ◽

Cited By ~ 13

Author(s):

L Pistelli ◽

P Perata ◽

A Alpi

Keyword(s):

Malate Dehydrogenase ◽

Enzyme Activities ◽

Citrate Synthase ◽

Isocitrate Lyase ◽

Glyoxylate Cycle ◽

Malate Synthase ◽

Cycle Enzyme ◽

Hydroxypyruvate Reductase ◽

Foliar Senescence ◽

The Glyoxylate Cycle

In order to elucidate the metabolism of the peroxisomes during foliar senescence of leaf beet (Beta vulgaris L., var. cicla), peroxisomal activities have been determined at various stages of senescence. Catalase and hydroxypyruvate reductase activities decreased whereas those of the β-oxidation pathway and glyoxylate cycle enzymes increased at the same time. The increased activities of malate synthase, isocitrate lyase, malate dehydrogenase and citrate synthase indicate that the glyoxylate cycle might be activated during the foliar senescence of leaf beet.

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STUDIES ON RUMEN COLIFORM ORGANISMS: II. UTILIZATION OF ACETATE BY ESCHERICHIA COLI 64 ISOLATED FROM THE RUMEN FLUID OF A COW FED ALFALFA HAY

Canadian Journal of Animal Science ◽

10.4141/cjas67-031 ◽

1967 ◽

Vol 47 (3) ◽

pp. 199-209 ◽

Cited By ~ 1

Author(s):

C. R. Krishnamurti ◽

L. W. McElroy

Keyword(s):

Sodium Acetate ◽

Isocitrate Lyase ◽

Protein Hydrolysate ◽

Rumen Fluid ◽

Glyoxylate Cycle ◽

Malate Synthase ◽

E Coli ◽

Spectrophotometric Methods ◽

Acetate Medium ◽

The Glyoxylate Cycle

When cells of E. coli 64 were harvested in their exponential phase of growth in an acetate medium and incubated aerobically with sodium acetate-2-C14, about 33% of the label appeared in CO2 after 1 hr. Of the radioactivity in the cells, 72% was recovered in the protein hydrolysate, 8% in the nucleic acid, 6% in the lipid and 14% in the ethanol-soluble fractions. The radioactivity in the protein hydrolysate of cells incubated with sodium acetate-2-C14 was approximately 20 times that in the hydrolysate of cells incubated with C14O2 as the carbon source. By spectrophotometric methods, it was demonstrated that cell-free extracts of cells grown on acetate contained acetate kinase and phosphate acetyltransferase, plus, as demonstrated by spectrophotometric and isotopic methods, isocitrate lyase and malate synthase which are characteristic of the glyoxylate cycle. The enzymes of the glyoxylate cycle could not be demonstrated in cell-free extracts of E. coli 64 grown on glucose under either aerobic or anaerobic conditions. Possible functions that E. coli 64 may have in the maintenance of anaerobiosis in the rumen and utilization of acetate through the glyoxylate pathway are discussed.

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Changes in metabolic reserves and enzyme activities during zoospore motility and cyst germination in Phytophthora palmivora

Canadian Journal of Botany ◽

10.1139/b75-170 ◽

1975 ◽

Vol 53 (14) ◽

pp. 1411-1416 ◽

Cited By ~ 24

Author(s):

Christina E. Bimpong

Keyword(s):

Specific Activity ◽

Isocitrate Lyase ◽

Glyoxylate Cycle ◽

Krebs Cycle ◽

Malate Synthase ◽

Phytophthora Palmivora ◽

Germination Period ◽

Major Energy Source ◽

The Glyoxylate Cycle ◽

Cyst Germination

Lipids measured as acyl glycerides and free fatty acids provided the major energy source during a 6-h motile and a 2-h germination period in zoospores and cysts, respectively, of Phytophthora palmivora. Carbohydrates and proteins decreased slightly during the 6-h motile period but increased significantly during germination. Specific activity of isocitrate lyase decreased both during zoospore motility and cyst germination. Only trace amounts of malate synthase activity were detected in zoospores and cysts. The activities of both NAD-isocitrate and malate dehydrogenases increased slightly, while those of NADP-isocitrate and succinate dehydrogenases decreased during the 6-h motile period. During the 2-h germination period the specific activities of NAD- and NADP-isocitrate, malate, and succinate dehydrogenases increased. It appears that during the motile stage the glyoxylate cycle provided more metabolites for the Krebs cycle than it did during germination.

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The localization of enzymes of intermediary metabolism in Astasia and Euglena

Biochemical Journal ◽

10.1042/bj1340607 ◽

1973 ◽

Vol 134 (2) ◽

pp. 607-616 ◽

Cited By ~ 13

Author(s):

Nicole Bégin-Heick

Keyword(s):

Succinate Dehydrogenase ◽

Isocitrate Lyase ◽

Tricarboxylic Acid Cycle ◽

Glyoxylate Cycle ◽

Intracellular Localization ◽

Tricarboxylic Acid ◽

Malate Synthase ◽

Particulate Fraction ◽

Acid Cycle ◽

The Glyoxylate Cycle

Results are presented on the intracellular localization of some of the enzymes of gluconeogenesis, of the tricarboxylic acid cycle and of related enzymes in Astasia and Euglena grown with various substrates. The results indicate the particulate nature of at least part of the malate synthase of Astasia and of part of the malate synthase and isocitrate lyase in Euglena. However, the presence of glyoxysomes (microbodies) in Astasia and Euglena is still open to question, since it has not, so far, been possible to separate the enzymes of the glyoxylate cycle from succinate dehydrogenase in the particulate fraction.

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Anaerobic Induction of Isocitrate Lyase and Malate Synthase in Submerged Rice Seedlings Indicates the Important Metabolic Role of the Glyoxylate Cycle

Acta Biochimica et Biophysica Sinica ◽

10.1111/j.1745-7270.2005.00060.x ◽

2005 ◽

Vol 37 (6) ◽

pp. 406-414 ◽

Cited By ~ 20

Author(s):

Ying Lu ◽

Yong-Rui Wu ◽

Bin Han

Keyword(s):

Isocitrate Lyase ◽

Tricarboxylic Acid Cycle ◽

Glyoxylate Cycle ◽

Fold Increase ◽

Malate Synthase ◽

Acetate Metabolism ◽

Activity Assay ◽

Rice Seedlings ◽

Metabolic Role ◽

The Glyoxylate Cycle

Abstract The glyoxylate cycle is a modified form of the tricarboxylic acid cycle that converts C2 compounds into C4 dicarboxylic acids at plant developmental stages. By studying submerged rice seedlings, we revealed the activation of the glyoxylate cycle by identifying the increased transcripts of mRNAs of the genes of isocitrate lyase (ICL) and malate synthase (MS), two characteristic enzymes of the glyoxylate cycle. Northern blot analysis showed that ICL and MS were activated in the prolonged anaerobic environment. The activity assay of pyruvate decarboxylase and ICL in the submerged seedlings indicated an 8.8-fold and 3.5-fold increase over that in the unsubmerged seedlings, respectively. The activity assay of acetyl-coenzyme A synthetase in the submerged seedlings indicated a 3-fold increase over that in the unsubmerged seedlings, which is important for initiating acetate metabolism. Consequently, we concluded that the glyoxylate cycle was involved in acetate metabolism under anaerobic conditions.

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Inhibitory Effects of Diketopiperazines from Marine-Derived Streptomyces puniceus on the Isocitrate Lyase of Candida albicans

Molecules ◽

10.3390/molecules24112111 ◽

2019 ◽

Vol 24 (11) ◽

pp. 2111 ◽

Cited By ~ 4

Author(s):

Heegyu Kim ◽

Ji-Yeon Hwang ◽

Jongheon Shin ◽

Ki-Bong Oh

Keyword(s):

Candida Albicans ◽

Cyclic Peptides ◽

Inhibitory Concentration ◽

Isocitrate Lyase ◽

Glyoxylate Cycle ◽

Malate Synthase ◽

Wild Type ◽

Inhibitory Effects ◽

Reported Data ◽

The Glyoxylate Cycle

The glyoxylate cycle is a sequence of anaplerotic reactions catalyzed by the key enzymes isocitrate lyase (ICL) and malate synthase, and plays an important role in the pathogenesis of microorganisms during infection. An icl-deletion mutant of Candida albicans exhibited reduced virulence in mice compared with the wild type. Five diketopiperazines, which are small and stable cyclic peptides, isolated from the marine-derived Streptomyces puniceus Act1085, were evaluated for their inhibitory effects on C. albicans ICL. The structures of these compounds were elucidated based on spectroscopic data and comparisons with previously reported data. Cyclo(L-Phe-L-Val) was identified as a potent ICL inhibitor, with a half maximal inhibitory concentration of 27 μg/mL. Based on the growth phenotype of the icl-deletion mutants and icl expression analyses, we demonstrated that cyclo(L-Phe-L-Val) inhibits the gene transcription of ICL in C. albicans under C2-carbon-utilizing conditions.

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Major roles of isocitrate lyase and malate synthase in bacterial and fungal pathogenesis

Microbiology ◽

10.1099/mic.0.030858-0 ◽

2009 ◽

Vol 155 (10) ◽

pp. 3166-3175 ◽

Cited By ~ 166

Author(s):

M. F. Dunn ◽

J. A. Ramírez-Trujillo ◽

I. Hernández-Lucas

Keyword(s):

Isocitrate Lyase ◽

Glyoxylate Cycle ◽

Tca Cycle ◽

Malate Synthase ◽

The Tca Cycle ◽

Plant Pathogenesis ◽

Micro Organisms ◽

The Glyoxylate Cycle ◽

Anaplerotic Pathway

The glyoxylate cycle is an anaplerotic pathway of the tricarboxylic acid (TCA) cycle that allows growth on C2 compounds by bypassing the CO2-generating steps of the TCA cycle. The unique enzymes of this route are isocitrate lyase (ICL) and malate synthase (MS). ICL cleaves isocitrate to glyoxylate and succinate, and MS converts glyoxylate and acetyl-CoA to malate. The end products of the bypass can be used for gluconeogenesis and other biosynthetic processes. The glyoxylate cycle occurs in Eukarya, Bacteria and Archaea. Recent studies of ICL- and MS-deficient strains as well as proteomic and transcriptional analyses show that these enzymes are often important in human, animal and plant pathogenesis. These studies have extended our understanding of the metabolic pathways essential for the survival of pathogens inside the host and provide a more complete picture of the physiology of pathogenic micro-organisms. Hopefully, the recent knowledge generated about the role of the glyoxylate cycle in virulence can be used for the development of new vaccines, or specific inhibitors to combat bacterial and fungal diseases.

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Flexible metabolism in Metarhizium anisopliae and Beauveria bassiana: role of the glyoxylate cycle during insect pathogenesis

Microbiology ◽

10.1099/mic.0.042697-0 ◽

2011 ◽

Vol 157 (1) ◽

pp. 199-208 ◽

Cited By ~ 21

Author(s):

Israel Enrique Padilla-Guerrero ◽

Larissa Barelli ◽

Gloria Angélica González-Hernández ◽

Juan Carlos Torres-Guzmán ◽

Michael J. Bidochka

Keyword(s):

Beauveria Bassiana ◽

Metarhizium Anisopliae ◽

Citrate Synthase ◽

Isocitrate Lyase ◽

Glyoxylate Cycle ◽

Pathogenic Fungi ◽

Malate Synthase ◽

Appressorium Formation ◽

Insect Pathogenic Fungi ◽

The Glyoxylate Cycle

Insect pathogenic fungi such as Metarhizium anisopliae and Beauveria bassiana have an increasing role in the control of agricultural insect pests and vectors of human diseases. Many of the virulence factors are well studied but less is known of the metabolism of these fungi during the course of insect infection or saprobic growth. Here, we assessed enzyme activity and gene expression in the central carbon metabolic pathway, including isocitrate dehydrogenase, aconitase, citrate synthase, malate synthase (MLS) and isocitrate lyase (ICL), with particular attention to the glyoxylate cycle when M. anisopliae and B. bassiana were grown under various conditions. We observed that ICL and MLS, glyoxylate cycle intermediates, were upregulated during growth on 2-carbon compounds (acetate and ethanol) as well as in insect haemolymph. We fused the promoter of the M. anisopliae ICL gene (Ma-icl) to a marker gene (mCherry) and showed that Ma-icl was upregulated when M. anisopliae was grown in the presence of acetate. Furthermore, Ma-icl was upregulated when fungi were engulfed by insect haemocytes as well as during appressorium formation. Addition of the ICL inhibitor 3-nitroproprionate delayed conidial germination and inhibited appressorium formation. These results show that these insect pathogenic fungi have a flexible metabolism that includes the glyoxylate cycle as an integral part of germination, pathogenesis and saprobic growth.

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