Effect of Leaf Senescence on Glyoxylate Cycle Enzyme Activities

1992 ◽  
Vol 19 (6) ◽  
pp. 723 ◽  
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.

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

2001 ◽  
Vol 29 (2) ◽  
pp. 283-286 ◽  
Author(s):  
E. L. Rylott ◽  
M. A. Hooks ◽  
I. A. Graham
Keyword(s):  
Arabidopsis Thaliana ◽  
Enzyme Activities ◽  
Phosphoenolpyruvate Carboxykinase ◽  
Isocitrate Lyase ◽  
Glyoxylate Cycle ◽  
Molecular Genetic ◽  
Regulation Of Gene Expression ◽  
Growth Period ◽  
Malate Synthase ◽  
The Glyoxylate Cycle

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.

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

Microbiology ◽  
2011 ◽  
Vol 157 (1) ◽  
pp. 199-208 ◽  
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.

Acetate metabolism in Escherichia coli

1978 ◽  
Vol 24 (2) ◽  
pp. 149-153 ◽  
Author(s):  
T. M. Lakshmi ◽  
Robert B. Helling
Keyword(s):  
Isocitrate Dehydrogenase ◽  
Citrate Synthase ◽  
Isocitrate Lyase ◽  
Glyoxylate Cycle ◽  
Acetate Metabolism ◽  
Wild Type ◽  
Intermediary Metabolites ◽  
Lyase Activity ◽  
Acetate Medium ◽  
The Glyoxylate Cycle

Levels of several intermediary metabolites were measured in cells grown in acetate medium in order to test the hypothesis that the glyoxylate cycle is repressed by phosphoenolpyruvate (PEP). Wild-type cells had less PEP than either isocitrate dehydrogenase – deficient cells (which had greater isocitrate lyase activity than the wild type) or isocitrate dehydrogenase – deficient, citrate synthase – deficient cells (which are poorly inducible). Thus induction of the glyoxylate cycle is more complicated than a simple function of PEP concentration. No correlation between enzyme activity and the level of oxaloacetate, pyruvate, or citrate was found either. Citrate was synthesized in citrate synthase – deficient mutants, possibly via citrate lyase.

The glyoxylate cycle enzyme activities in the pathogenic isolates of Candida albicans obtained from HIV/AIDS, diabetic and burn patients

Mycoses ◽  
2006 ◽  
Vol 49 (2) ◽  
pp. 85-90 ◽  
Author(s):  
Ali Abdul Lattif ◽  
Rajendra Prasad ◽  
Uma Banerjee ◽  
Nivedita Gupta ◽  
Sameer Mohammad ◽  
...  
Keyword(s):  
Candida Albicans ◽  
Enzyme Activities ◽  
Glyoxylate Cycle ◽  
Burn Patients ◽  
Cycle Enzyme ◽  
The Glyoxylate Cycle ◽  
Hiv Aids

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

1967 ◽  
Vol 47 (3) ◽  
pp. 199-209 ◽  
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.

Characterization of a Bifunctional Glyoxylate Cycle Enzyme, Malate Synthase/Isocitrate Lyase, of Euglena gracilis

2011 ◽  
Vol 58 (2) ◽  
pp. 128-133 ◽  
Author(s):  
MASAMI NAKAZAWA ◽  
MASAAKI NISHIMURA ◽  
KENGO INOUE ◽  
MITSUHIRO UEDA ◽  
HIROSHI INUI ◽  
...  
Keyword(s):  
Euglena Gracilis ◽  
Isocitrate Lyase ◽  
Glyoxylate Cycle ◽  
Malate Synthase ◽  
Cycle Enzyme

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

1975 ◽  
Vol 53 (14) ◽  
pp. 1411-1416 ◽  
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.

Tricarboxylic acid and glyoxylate cycle enzyme activities in Thiobacillus versutus, an isocitrate lyase negative organism

1986 ◽  
Vol 145 (2) ◽  
pp. 148-152 ◽  
Author(s):  
Pieternel A. M. Claassen ◽  
Gerard J. J. Kortstee ◽  
Johannes P. van Dijken ◽  
Wim Harder
Keyword(s):  
Enzyme Activities ◽  
Isocitrate Lyase ◽  
Glyoxylate Cycle ◽  
Tricarboxylic Acid ◽  
Cycle Enzyme ◽  
Thiobacillus Versutus

scholarly journals The localization of enzymes of intermediary metabolism in Astasia and Euglena

1973 ◽  
Vol 134 (2) ◽  
pp. 607-616 ◽  
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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