Apparent isocitrate lyase activity in Leishmania amazonensis

2017 ◽  
Vol 62 (4) ◽  
Author(s):  
Concepción Hernández-Chinea ◽  
Laura Maimone ◽  
Yelitza Campos ◽  
Walter Mosca ◽  
Pedro J. Romero

AbstractEarly reports have demonstrated the occurrence of glyoxylate cycle enzymes in several

1978 ◽  
Vol 24 (2) ◽  
pp. 149-153 ◽  
Author(s):  
T. M. Lakshmi ◽  
Robert B. Helling

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.


1989 ◽  
Vol 67 (2) ◽  
pp. 447-450 ◽  
Author(s):  
B. Dehorter ◽  
L. Lacoste

The activity of two enzymes of the tricarboxylic acid cycle (NADP+-isocitrate dehydrogenase, EC 1.1.1.42) and the glyoxylate cycle (isocitrate lyase, EC 4.1.3.1) were assayed in vitro to determine the effects of darkness, light, and mycosporin (P310) on sexual morphogenesis in Nectria galligena Bres. In the absence of mycosporin, high isocitrate lyase activity was associated with vegetative growth of fungi kept in the dark. In contrast, light-induced perithecial development and mycosporin biosynthesis could be correlated with high ratios of isocitrate dehydrogenase to isocitrate lyase activity. This was confirmed by the fact that when mycosporin was added to the nutrient medium with incubation in darkness, the fertility of the fungus was partially expressed and the activity of isocitrate lyase was significantly reduced. Thus this enzyme would be repressed in vivo by mycosporin. Because of its photomimetic role in sexual differentiation and regulation of intermediate metabolism, mycosporin appears to be a biochemical transmitter of light energy required for the formation of ascocarps.


2005 ◽  
Vol 187 (4) ◽  
pp. 1415-1425 ◽  
Author(s):  
Michael Meister ◽  
Stephan Saum ◽  
Birgit E. Alber ◽  
Georg Fuchs

ABSTRACT Cell extracts of Rhodobacter capsulatus grown on acetate contained an apparent malate synthase activity but lacked isocitrate lyase activity. Therefore, R. capsulatus cannot use the glyoxylate cycle for acetate assimilation, and a different pathway must exist. It is shown that the apparent malate synthase activity is due to the combination of a malyl-coenzyme A (CoA) lyase and a malyl-CoA-hydrolyzing enzyme. Malyl-CoA lyase activity was 20-fold up-regulated in acetate-grown cells versus glucose-grown cells. Malyl-CoA lyase was purified 250-fold with a recovery of 6%. The enzyme catalyzed not only the reversible condensation of glyoxylate and acetyl-CoA to l-malyl-CoA but also the reversible condensation of glyoxylate and propionyl-CoA to β-methylmalyl-CoA. Enzyme activity was stimulated by divalent ions with preference for Mn2+ and was inhibited by EDTA. The N-terminal amino acid sequence was determined, and a corresponding gene coding for a 34.2-kDa protein was identified and designated mcl1. The native molecular mass of the purified protein was 195 ± 20 kDa, indicating a homohexameric composition. A homologous mcl1 gene was found in the genomes of the isocitrate lyase-negative bacteria Rhodobacter sphaeroides and Rhodospirillum rubrum in similar genomic environments. For Streptomyces coelicolor and Methylobacterium extorquens, mcl1 homologs are located within gene clusters implicated in acetate metabolism. We therefore propose that l-malyl-CoA/β-methylmalyl-CoA lyase encoded by mcl1 is involved in acetate assimilation by R. capsulatus and possibly other glyoxylate cycle-negative bacteria.


1999 ◽  
Vol 181 (23) ◽  
pp. 7161-7167 ◽  
Author(s):  
Kerstin Höner Zu Bentrup ◽  
Andras Miczak ◽  
Dana L. Swenson ◽  
David G. Russell

ABSTRACT Analysis by two-dimensional gel electrophoresis revealed thatMycobacterium avium expresses several proteins unique to an intracellular infection. One abundant protein with an apparent molecular mass of 50 kDa was isolated, and the N-terminal sequence was determined. It matches a sequence in the M. tuberculosisdatabase (Sanger) with similarity to the enzyme isocitrate lyase of both Corynebacterium glutamicum and Rhodococcus fascians. Only marginal similarity was observed between this open reading frame (ORF) (termed icl) and a second distinct ORF (named aceA) which exhibits a low similarity to other isocitrate lyases. Both ORFs can be found as distinct genes in the various mycobacterial databases recently published. Isocitrate lyase is a key enzyme in the glyoxylate cycle and is essential as an anapleurotic enzyme for growth on acetate and certain fatty acids as carbon source. In this study we express and purify Icl, as well as AceA proteins, and show that both exhibit isocitrate lyase activity. Various known inhibitors for isocitrate lyase were effective. Furthermore, we present evidence that in both M. avium and M. tuberculosis the production and activity of the isocitrate lyase is enhanced under minimal growth conditions when supplemented with acetate or palmitate.


2001 ◽  
Vol 29 (2) ◽  
pp. 283-286 ◽  
Author(s):  
E. L. Rylott ◽  
M. A. Hooks ◽  
I. A. Graham

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.


1997 ◽  
Vol 53 (4) ◽  
pp. 488-490 ◽  
Author(s):  
S. J. Langridge ◽  
P. J. Baker ◽  
J. R. De Lucas ◽  
S. E. Sedelnikova ◽  
G. Turner ◽  
...  

1983 ◽  
Vol 66 (6) ◽  
pp. 1232-1236 ◽  
Author(s):  
M.C. Albizzatti de Rivadeneira ◽  
M.C. Manca de Nadra ◽  
A.A. Pesce de Ruiz Holgado ◽  
G. Oliver

2008 ◽  
Vol 57 (11) ◽  
pp. 1322-1328 ◽  
Author(s):  
Sophit Thirach ◽  
Chester R. Cooper ◽  
Nongnuch Vanittanakom

Penicillium marneffei is an intracellular dimorphic fungus that can cause a fatal disseminated disease in human immunodeficiency virus-infected patients. The factors that affect the pathogenicity of this fungus remain unclear. Here, we report the isolation and characterization of the gpdA cDNA and genomic clones encoding glyceraldehyde-3-phosphate dehydrogenase (GAPDH) in P. marneffei. Phylogenetic analysis of GAPDH amino acid sequences demonstrated the evolutionary relationship of P. marneffei to other fungi, including the intracellular pathogen Ajellomyces capsulatus. To assess the central importance of phagocytic cells in defence against P. marneffei infection, we used Northern blotting to investigate the response of the isocitrate lyase-encoding gene (acuD) and gpdA to nutrient deprivation inside macrophages. The results revealed that after macrophage internalization, the gene involved in the glyoxylate cycle, acuD, showed higher expression levels as early as 2 h from the start of co-incubation, and the differential expression could be observed again at 8 h after infection. In contrast, the expression of gpdA was downregulated in the yeast phase, as well as during macrophage infection after 2, 4 and 8 h of infection. The induction of P. marneffei acuD was shown to be coordinated with the downregulation of the glycolytic gpdA gene, implying that the cytoplasmic environment of macrophages is deficient in glucose and the glyoxylate pathway could be used by this pathogen to allow subsistence on two-carbon compounds within the host cell following its intracellular persistence.


2008 ◽  
Vol 190 (20) ◽  
pp. 6697-6705 ◽  
Author(s):  
William L. Franck ◽  
Woo-Suk Chang ◽  
Jing Qiu ◽  
Masayuki Sugawara ◽  
Michael J. Sadowsky ◽  
...  

ABSTRACT Bradyrhizobium japonicum is a facultative chemoautotroph capable of utilizing hydrogen gas as an electron donor in a respiratory chain terminated by oxygen to provide energy for cellular processes and carbon dioxide assimilation via a reductive pentose phosphate pathway. A transcriptomic analysis of B. japonicum cultured chemoautotrophically identified 1,485 transcripts, representing 17.5% of the genome, as differentially expressed when compared to heterotrophic cultures. Genetic determinants required for hydrogen utilization and carbon fixation, including the uptake hydrogenase system and components of the Calvin-Benson-Bassham cycle, were strongly induced in chemoautotrophically cultured cells. A putative isocitrate lyase (aceA; blr2455) was among the most strongly upregulated genes, suggesting a role for the glyoxylate cycle during chemoautotrophic growth. Addition of arabinose to chemoautotrophic cultures of B. japonicum did not significantly alter transcript profiles. Furthermore, a subset of nitrogen fixation genes was moderately induced during chemoautotrophic growth. In order to specifically address the role of isocitrate lyase and nitrogenase in chemoautotrophic growth, we cultured aceA, nifD, and nifH mutants under chemoautotrophic conditions. Growth of each mutant was similar to that of the wild type, indicating that the glyoxylate bypass and nitrogenase activity are not essential components of chemoautotrophy in B. japonicum.


Weed Science ◽  
1970 ◽  
Vol 18 (5) ◽  
pp. 565-571
Author(s):  
J. A. Mulliken ◽  
C. A. Kust ◽  
L. E. Schrader

Endosperm dry weight, protein, and fat losses accompanied rapid radicle growth of velvetleaf (Abutilon theophrasti Medic.) between 12 and 36 hr of germination at 31 C. Cotyledonary reserves were mobilized after 36 hr. Isocitrate lyase activity sedimented with a particulate fraction in varying degrees, but maximal activity developed at times coincident with fat mobilization. Respiration of excised endosperms reached maximal rates shortly after radicle emergence. The actions of hydrogen cyanide, carbon monoxide, and 2,4-dinitrolphenol indicated that respiration of endosperms excised from imbibed and germinated seed was due to cytochrome oxidase activity, and was coupled to phosphorylation.


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