Re-Activation of the Expression of Glyoxysomal Genes in Green Plant Tissue

Abstract Biochemie, Fachbereich Chemie, Universität Marburg, Hans-Meerwein-Straße, D-3550 Marburg, Bundesrepublik Deutschland Z. Naturforsch. 45c, Isocitrate Lyase c DNA, Malate Synthase c DNA, Glyoxysome, Leaf Peroxisome, Transition of Organelles Glyoxysomes are being replaced by leaf-type peroxisom es during the greening of dark-grown cucumber cotyledons. Light functions in this process as negative modulator of the gene expression of glyoxylate cycle enzymes but as positive regulator for the activation of glycollate oxidase formation. The differential gene expression was investigated at the level of m RNA amounts using c DNA probes hybridizing with malate synthase m RNA, isocitrate lyase m RNA, and glycollate oxidase m RNA. Hybrid ization probes were obtained from a c DNA library complementary to the germinationspecific m RNA s of cucumber cotyledons. The process of replacem ent of glyoxysomal proteins by leaf peroxisom al proteins was reversed to a certain extend when greened cotyledons were brought back in the dark. Hybridization on Northern b lots provided evidences that in greened cotyledons the amount of malate synthase m RNA and isocitratelyase m RNA starts to increase up on dark treatment.

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Gene Expression Profiling in the Human Pathogenic Dermatophyte Trichophyton rubrum during Growth on Proteins

Eukaryotic Cell ◽

10.1128/ec.00208-08 ◽

2008 ◽

Vol 8 (2) ◽

pp. 241-250 ◽

Cited By ~ 41

Author(s):

Christophe Zaugg ◽

Michel Monod ◽

Johann Weber ◽

Keith Harshman ◽

Sylvain Pradervand ◽

...

Keyword(s):

Gene Expression ◽

Trichophyton Rubrum ◽

Isocitrate Lyase ◽

Glyoxylate Cycle ◽

Pathogenic Fungi ◽

In Vitro Digestion ◽

Malate Synthase ◽

Transcriptional Analysis ◽

Large Set

ABSTRACT Dermatophytes are highly specialized filamentous fungi which cause the majority of superficial mycoses in humans and animals. The high secreted proteolytic activity of these microorganisms during growth on proteins is assumed to be linked to their particular ability to exclusively infect keratinized host structures such as the skin stratum corneum, hair, and nails. Individual secreted dermatophyte proteases were recently described and linked with the in vitro digestion of keratin. However, the overall adaptation and transcriptional response of dermatophytes during protein degradation are largely unknown. To address this question, we constructed a cDNA microarray for the human pathogenic dermatophyte Trichophyton rubrum that was based on transcripts of the fungus grown on proteins. Profiles of gene expression during the growth of T. rubrum on soy and keratin protein displayed the activation of a large set of genes that encode secreted endo- and exoproteases. In addition, other specifically induced factors potentially implicated in protein utilization were identified, including heat shock proteins, transporters, metabolic enzymes, transcription factors, and hypothetical proteins with unknown functions. Of particular interest is the strong upregulation of key enzymes of the glyoxylate cycle in T. rubrum during growth on soy and keratin, namely, isocitrate lyase and malate synthase. This broad-scale transcriptional analysis of dermatophytes during growth on proteins reveals new putative pathogenicity-related host adaptation mechanisms of these human pathogenic fungi.

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Changes in microbody-marker enzymes during growth of Tetrahymena pyriformis E

Proceedings of the Royal Society of London Series B Biological Sciences ◽

10.1098/rspb.1974.0003 ◽

1974 ◽

Vol 185 (1078) ◽

pp. 19-31 ◽

Cited By ~ 5

Keyword(s):

Specific Activity ◽

Isocitrate Lyase ◽

Glyoxylate Cycle ◽

Tetrahymena Pyriformis ◽

Growth Conditions ◽

Malate Synthase ◽

Glycollate Oxidase ◽

Specific Activities ◽

Peptone Medium ◽

The Glyoxylate Cycle

Marked differences in the rates of synthesis of several microbody (peroxisome) enzymes have been observed during the growth of Tetrahymena pyriformis (strain E) in shaking or static peptone medium. The specific activities of catalase and NADP + -isocitrate dehydrogenase, and of the mitochondrial enzyme fumarase, remained virtually constant during exponential growth under all conditions examined, whereas that of glycollate oxidase decreased dramatically in the course of growth. In contrast, isocitrate lyase and malate synthase were synthesized at increasing rates during growth on peptone medium with or without added acetate; highest specific activities were reached in late exponential to early stationary phase. The synthesis of these two enzymes, which appears to be coordinately regulated, was repressed in medium supplemented with glucose. Despite these variations in specific activity, glycollate oxidase as well as the key enzymes of the glyoxylate cycle remained associated with microbodies under all growth conditions tested.

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

Biochemical Society Transactions ◽

10.1042/bst0290283 ◽

2001 ◽

Vol 29 (2) ◽

pp. 283-286 ◽

Cited By ~ 54

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.

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Mechanism of phosphate solubilization and antifungal activity of Streptomyces spp. isolated from wheat roots and rhizosphere and their application in improving plant growth

Microbiology ◽

10.1099/mic.0.074146-0 ◽

2014 ◽

Vol 160 (4) ◽

pp. 778-788 ◽

Cited By ~ 107

Author(s):

Rahul Jog ◽

Maharshi Pandya ◽

G. Nareshkumar ◽

Shalini Rajkumar

Keyword(s):

Gene Expression ◽

Antifungal Activity ◽

Plant Growth ◽

Potential Field ◽

Phosphate Solubilization ◽

Isocitrate Lyase ◽

Malate Synthase ◽

Plant Growth Promoting Activities ◽

Plant Growth Promoting ◽

Growth Promoting

The application of plant-growth-promoting rhizobacteria (PGPR) at field scale has been hindered by an inadequate understanding of the mechanisms that enhance plant growth, rhizosphere incompetence and the inability of bacterial strains to thrive in different soil types and environmental conditions. Actinobacteria with their sporulation, nutrient cycling, root colonization, bio-control and other plant-growth-promoting activities could be potential field bio-inoculants. We report the isolation of five rhizospheric and two root endophytic actinobacteria from Triticum aestivum (wheat) plants. The cultures exhibited plant-growth-promoting activities, namely phosphate solubilization (1916 mg l−1), phytase (0.68 U ml−1), chitinase (6.2 U ml−1), indole-3-acetic acid (136.5 mg l−1) and siderophore (47.4 mg l−1) production, as well as utilizing all the rhizospheric sugars under test. Malate (50–55 mmol l−1) was estimated in the culture supernatant of the highest phosphate solublizer, Streptomyces mhcr0816. The mechanism of malate overproduction was studied by gene expression and assays of key glyoxalate cycle enzymes – isocitrate dehydrogenase (IDH), isocitrate lyase (ICL) and malate synthase (MS). The significant increase in gene expression (ICL fourfold, MS sixfold) and enzyme activity (ICL fourfold, MS tenfold) of ICL and MS during stationary phase resulted in malate production as indicated by lowered pH (2.9) and HPLC analysis (retention time 13.1 min). Similarly, the secondary metabolites for chitinase-independent biocontrol activity of Streptomyces mhcr0817, as identified by GC-MS and 1H-NMR spectra, were isoforms of pyrrole derivatives. The inoculation of actinobacterial isolate mhce0811 in T. aestivum (wheat) significantly improved plant growth, biomass (33 %) and mineral (Fe, Mn, P) content in non-axenic conditions. Thus the actinobacterial isolates reported here were efficient PGPR possessing significant antifungal activity and may have potential field applications.

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Identification of RamA, a Novel LuxR-Type Transcriptional Regulator of Genes Involved in Acetate Metabolism of Corynebacterium glutamicum

Journal of Bacteriology ◽

10.1128/jb.188.7.2554-2567.2006 ◽

2006 ◽

Vol 188 (7) ◽

pp. 2554-2567 ◽

Cited By ~ 76

Author(s):

Annette Cramer ◽

Robert Gerstmeir ◽

Steffen Schaffer ◽

Michael Bott ◽

Bernhard J. Eikmanns

Keyword(s):

Corynebacterium Glutamicum ◽

Isocitrate Lyase ◽

Glyoxylate Cycle ◽

Transcriptional Regulator ◽

Malate Synthase ◽

Acetate Kinase ◽

Acetate Metabolism ◽

Promoter Regions ◽

Cell Extracts ◽

Peptide Mass

ABSTRACT In Corynebacterium glutamicum, the acetate-activating enzymes phosphotransacetylase and acetate kinase and the glyoxylate cycle enzymes isocitrate lyase and malate synthase are coordinately up-regulated in the presence of acetate in the growth medium. This regulation is due to transcriptional control of the respective pta-ack operon and the aceA and aceB genes, brought about at least partly by the action of the negative transcriptional regulator RamB. Using cell extracts of C. glutamicum and employing DNA affinity chromatography, mass spectrometry, and peptide mass fingerprinting, we identified a LuxR-type transcriptional regulator, designated RamA, which binds to the pta-ack and aceA/aceB promoter regions. Inactivation of the ramA gene in the genome of C. glutamicum resulted in mutant RG2. This mutant was unable to grow on acetate as the sole carbon and energy source and, in comparison to the wild type of C. glutamicum, showed very low specific activities of phosphotransacetylase, acetate kinase, isocitrate lyase, and malate synthase, irrespective of the presence of acetate in the medium. Comparative transcriptional cat fusion experiments revealed that this deregulation takes place at the level of transcription. By electrophoretic mobility shift analysis, purified His-tagged RamA protein was shown to bind specifically to the pta-ack and the aceA/aceB promoter regions, and deletion and mutation studies revealed in both regions two binding motifs each consisting of tandem A/C/TG4-6T/C or AC4-5A/G/T stretches separated by four or five arbitrary nucleotides. Our data indicate that RamA represents a novel LuxR-type transcriptional activator of genes involved in acetate metabolism of C. glutamicum.

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Physiological Ecology of Stenoxybacter acetivorans, an Obligate Microaerophile in Termite Guts

Applied and Environmental Microbiology ◽

10.1128/aem.00787-07 ◽

2007 ◽

Vol 73 (21) ◽

pp. 6829-6841 ◽

Cited By ~ 25

Author(s):

John T. Wertz ◽

John A. Breznak

Keyword(s):

Isocitrate Lyase ◽

Tricarboxylic Acid Cycle ◽

Glyoxylate Cycle ◽

Reticulitermes Flavipes ◽

Peripheral Region ◽

Malate Synthase ◽

Rrna Gene ◽

Potential Contribution ◽

Cell Extracts

ABSTRACT Stenoxybacter acetivorans is a newly described, obligately microaerophilic β-proteobacterium that is abundant in the acetate-rich hindgut of Reticulitermes. Here we tested the hypotheses that cells are located in the hypoxic, peripheral region of Reticulitermes flavipes hindguts and use acetate to fuel their O2-consuming respiratory activity in situ. Physical fractionation of R. flavipes guts, followed by limited-cycle PCR with S. acetivorans-specific 16S rRNA gene primers, indicated that cells of this organism were indeed located primarily among the microbiota colonizing the hindgut wall. Likewise, reverse transcriptase PCR of hindgut RNA revealed S. acetivorans-specific transcripts for acetate-activating enzymes that were also found in cell extracts (acetate kinase and phosphotransacetylase), as well as transcripts of ccoN, which encodes the O2-reducing subunit of high-affinity cbb 3-type cytochrome oxidases. However, S. acetivorans strains did not possess typical enzymes of the glyoxylate cycle (isocitrate lyase and malate synthase A), suggesting that they may use an alternate pathway to replenish tricarboxylic acid cycle intermediates or they obtain such compounds (or their precursors) in situ. Respirometric measurements indicated that much of the O2 consumption by R. flavipes worker larvae was attributable to their guts, and the potential contribution of S. acetivorans to O2 consumption by extracted guts was about 0.2%, a value similar to that obtained for other hindgut bacteria examined. Similar measurements obtained with guts of larvae prefed diets to disrupt major members of the hindgut microbiota implied that most of the O2 consumption observed with extracted guts was attributable to protozoans, a group of microbes long thought to be “strict anaerobes.”

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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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Gene Expression Response ofTrichophyton rubrumduring Coculture on Keratinocytes Exposed to Antifungal Agents

Evidence-based Complementary and Alternative Medicine ◽

10.1155/2015/180535 ◽

2015 ◽

Vol 2015 ◽

pp. 1-7 ◽

Cited By ~ 15

Author(s):

Tatiana Takahasi Komoto ◽

Tamires Aparecida Bitencourt ◽

Gabriel Silva ◽

Rene Oliveira Beleboni ◽

Mozart Marins ◽

...

Keyword(s):

Gene Expression ◽

Molecular Mechanisms ◽

Citrate Synthase ◽

Isocitrate Lyase ◽

Glyoxylate Cycle ◽

Serine Proteinase ◽

Gene Expression Response ◽

Fungal Host ◽

Host Interaction ◽

Genes Encoding

Trichophyton rubrumis the most common causative agent of dermatomycoses worldwide, causing infection in the stratum corneum, nails, and hair. Despite the high prevalence of these infections, little is known about the molecular mechanisms involved in the fungal-host interaction, particularly during antifungal treatment. The aim of this work was to evaluate the gene expression ofT. rubrumcocultured with keratinocytes and treated with the flavonoidtrans-chalcone and the glycoalkaloidα-solanine. Both substances showed a marked antifungal activity againstT. rubrumstrain CBS (MIC = 1.15 and 17.8 µg/mL, resp.). Cytotoxicity assay against HaCaT cells produced IC50values of 44.18 totrans-chalcone and 61.60 µM toα-solanine. The interaction of keratinocytes withT. rubrumconidia upregulated the expression of genes involved in the glyoxylate cycle, ergosterol synthesis, and genes encoding proteases but downregulated the ABC transporterTruMDR2 gene. However, both antifungals downregulated the ERG1 and ERG11, metalloprotease 4, serine proteinase, andTruMDR2 genes. Furthermore, thetrans-chalcone downregulated the genes involved in the glyoxylate pathway, isocitrate lyase, and citrate synthase. Considering the urgent need for more efficient and safer antifungals, these results contribute to a better understanding of fungal-host interactions and to the discovery of new antifungal targets.

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