The physiology of conidial formation in submerged cultures of Claviceps purpurea (Fr.) Tul producing alkaloids

1974 ◽  
Vol 20 (10) ◽  
pp. 1323-1329 ◽  
Author(s):  
Z. Řeháček ◽  
J. Kozová ◽  
P. Sajdl ◽  
J. Voříšek
Keyword(s):  
Protein Synthesis ◽  
Citrate Synthase ◽  
Isocitrate Lyase ◽  
Malate Synthase ◽  
Claviceps Purpurea ◽  
Tryptophan Biosynthesis ◽  
Submerged Cultures ◽  
Stringent Control ◽  
Constant Rate ◽  
Conidial Formation

Conidial formation in C. purpurea is correlated with a rising ATP utilization, an almost constant rate of protein synthesis, a constant level of intracellular orthophosphate, an accumulation of mycelial lipids, and an increase in the activities of citrate synthase, isocitrate lyase, malate synthase, and intra- and extra-cellular proteinases. In the culture, stringent control of tryptophan biosynthesis is absent. Conidial formation is stimulated by MnCl2 (5.10−4 M) and suppressed by ergotamine (5.10−4 M), ergometrine (5.10−4 M), and glycerol (5.10−3 M), respectively. Ergotamine also lowers the activity of leucineaminopeptidase from the fungus. Alkaloids are synthesized only after conidial formation and the growing stage. In cultures treated with conidiation inhibitors (ergotamine and (or) glycerol), the alkaloid yield is enhanced. It is hypothesized that the concentration of intracellular tryptophan which accumulates during aging is lowered by conversion to alkaloids which are themselves capable of positive feedback which enhances further loss of tryptophan.

Incomplete Glyoxysomes Appearing at a Late Stage of Maturation of Cucumber Seeds

1979 ◽  
Vol 34 (12) ◽  
pp. 1232-1236 ◽  
Author(s):  
Wolfram Koller ◽  
Jürgen Frevert ◽  
Helmut Kindi
Keyword(s):  
Late Stage ◽  
Citrate Synthase ◽  
De Novo ◽  
Density Gradient Centrifugation ◽  
Isocitrate Lyase ◽  
Gradient Centrifugation ◽  
Protein Body ◽  
Electrophoretic Analysis ◽  
Malate Synthase ◽  
Lyase Activity

Seeds of cucumber fruits at a late stage of ripening were analyzed for microbodies and micro­body components. On isopycnic density gradient centrifugation of homogenates in the presence of EDTA, several particulate fractions were obtained: a light membraneous fraction (density d = 1.09-1.11 kg × 1-1), a mitochondria-enriched fraction (d = 1.21 kg × 1-1), a microbody-enriched fraction (d = 1.23 kg × 1-1), and a protein body fraction (d= 1.26 - 1.29 kg × 1-1). Microbo­dies were revealed by exactly coinciding peaks of malate synthase, catalase and crotonase; small proportions of citrate synthase and malate dehydrogenase were also present in this zone. Isocitrate lyase activity, however, did not occur in the seeds at this stage. The examination of enzyme activi­ties indicated the presence of microbodies which cannot function as competent glyoxysomes be­cause of the lack of isocitrate lyase. Moreover, de novo synthesis from [3H] leucine could be de­monstrated for malate synthase by means of immunoprecipitation of newly synthesized malate synthase and subsequent electrophoretic analysis.

scholarly journals The assimilation of carbon by Chloropseudomonas ethylicum

1968 ◽  
Vol 106 (3) ◽  
pp. 615-622 ◽  
Author(s):  
A G Callely ◽  
N. Rigopoulos ◽  
R. C. Fuller
Keyword(s):  
Carbon Dioxide ◽  
Phosphate Buffer ◽  
Citrate Synthase ◽  
Isocitrate Lyase ◽  
Fumarate Hydratase ◽  
Malate Synthase ◽  
Nutritional Requirements ◽  
Aconitate Hydratase ◽  
Oxoglutarate Dehydrogenase ◽  
Ribulose Diphosphate Carboxylase

1. The enzymes in ultrasonically prepared extracts of Chloropseudomonas ethylicum were studied to elucidate how this organism assimilates acetate and carbon dioxide and why it cannot grow with either of these two compounds alone. 2. Such extracts can (i) convert acetate and oxaloacetate into α-oxoglutarate, (ii) convert oxaloacetate into succinyl-CoA, (iii) convert phosphopyruvate into 3-phosphoglyceraldehyde and (iv) interconvert phosphopyruvate and pyruvate via oxaloacetate. 3. Pyruvate kinase, α-oxoglutarate dehydrogenase, ribulose diphosphate carboxylase, isocitrate lyase and malate synthase were not detected. 4. It is difficult to detect aconitate hydratase, fumarate hydratase and citrate synthase in extracts of the organism ultrasonically treated in tris buffer; to demonstrate these enzymes extracts should be prepared in phosphate buffer containing 2-mercaptoethanol. 5. Provided that this organism can synthesize pyruvate from acetate and carbon dioxide, the enzymes detected are sufficient to account for the nutritional requirements of this organism.

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.

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.

scholarly journals Progesterone Promotes Mitochondrial Respiration at the Biochemical and Molecular Level in Germinating Maize Seeds

Plants ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1326
Author(s):  
Hulya Turk
Keyword(s):  
Gene Expression ◽  
Mitochondrial Respiration ◽  
Citrate Synthase ◽  
Isocitrate Lyase ◽  
Malate Synthase ◽  
Total Soluble Protein ◽  
Total Carbohydrate ◽  
Expression Levels ◽  
Maize Seeds ◽  
Gene Expression Levels

This research aimed to investigate the effects of progesterone, a mammalian steroid sex hormone, on the mitochondrial respiration in germinating maize seeds. For this purpose, maize seeds were divided into four different groups (control, 10−6, 10−8, and 10−10 mol·L−1 progesterone) and were grown in a germination cabinet in the dark at 24.5 ± 0.5 °C for 4 d. The changes in gene expression levels of citrate synthase (CS), cytochrome oxidase (COX19), pyruvate dehydrogenase (Pdh1), and ATP synthase (ATP6), which is involved in mitochondrial respiration, were studied in root and cotyledon tissues. Significant increases were recorded in the gene expression levels of all studied enzymes. In addition, progesterone applications stimulated activities of malate synthase (MS), isocitrate lyase (ICL), and alpha-amylase, which are important enzymes of the germination step. The changes in gene expression levels of mas1 and icl1 were found parallel to the rise in these enzymes’ activities. It was determined similar increases in root and coleoptile lengths and total soluble protein and total carbohydrate contents. The most remarkable changes were detected in 10−8 mol·L−1 progesterone-treated seedlings. These results clearly indicate that progesterone stimulates mitochondrial respiration by inducing biochemical and molecular parameters and thus accelerates seed germination thanks to the activation of other pathways related to mitochondrial respiration.

scholarly journals Production of succinate by engineered strains of Synechocystis PCC 6803 overexpressing phosphoenolpyruvate carboxylase and a glyoxylate shunt

2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Claudia Durall ◽  
Kateryna Kukil ◽  
Jeffrey A. Hawkes ◽  
Alessia Albergati ◽  
Peter Lindblad ◽  
...  
Keyword(s):  
Phosphoenolpyruvate Carboxylase ◽  
Isocitrate Lyase ◽  
Tricarboxylic Acid Cycle ◽  
Cell Metabolism ◽  
Tca Cycle ◽  
Malate Synthase ◽  
Glyoxylate Shunt ◽  
Control Strain ◽  
Genes Encoding ◽  
Pcc 6803

Abstract Background Cyanobacteria are promising hosts for the production of various industrially important compounds such as succinate. This study focuses on introduction of the glyoxylate shunt, which is naturally present in only a few cyanobacteria, into Synechocystis PCC 6803. In order to test its impact on cell metabolism, engineered strains were evaluated for succinate accumulation under conditions of light, darkness and anoxic darkness. Each condition was complemented by treatments with 2-thenoyltrifluoroacetone, an inhibitor of succinate dehydrogenase enzyme, and acetate, both in nitrogen replete and deplete medium. Results We were able to introduce genes encoding the glyoxylate shunt, aceA and aceB, encoding isocitrate lyase and malate synthase respectively, into a strain of Synechocystis PCC 6803 engineered to overexpress phosphoenolpyruvate carboxylase. Our results show that complete expression of the glyoxylate shunt results in higher extracellular succinate accumulation compared to the wild type control strain after incubation of cells in darkness and anoxic darkness in the presence of nitrate. Addition of the inhibitor 2-thenoyltrifluoroacetone increased succinate titers in all the conditions tested when nitrate was available. Addition of acetate in the presence of the inhibitor further increased the succinate accumulation, resulting in high levels when phosphoenolpyruvate carboxylase was overexpressed, compared to control strain. However, the highest succinate titer was obtained after dark incubation of an engineered strain with a partial glyoxylate shunt overexpressing isocitrate lyase in addition to phosphoenolpyruvate carboxylase, with only 2-thenoyltrifluoroacetone supplementation to the medium. Conclusions Heterologous expression of the glyoxylate shunt with its central link to the tricarboxylic acid cycle (TCA) for acetate assimilation provides insight on the coordination of the carbon metabolism in the cell. Phosphoenolpyruvate carboxylase plays an important role in directing carbon flux towards the TCA cycle.

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 RamB, a Novel Transcriptional Regulator of Genes Involved in Acetate Metabolism of Corynebacterium glutamicum

2004 ◽  
Vol 186 (9) ◽  
pp. 2798-2809 ◽  
Author(s):  
Robert Gerstmeir ◽  
Annette Cramer ◽  
Petra Dangel ◽  
Steffen Schaffer ◽  
Bernhard J. Eikmanns
Keyword(s):  
Corynebacterium Glutamicum ◽  
Isocitrate Lyase ◽  
Transcriptional Regulator ◽  
Regulatory Elements ◽  
Malate Synthase ◽  
Acetate Kinase ◽  
Acetate Metabolism ◽  
Peptide Mass ◽  
Specific Activities ◽  
High Level

ABSTRACT The adaptation of Corynebacterium glutamicum to acetate as a carbon and energy source involves transcriptional regulation of the pta-ack operon coding for the acetate-activating enzymes phosphotransacetylase and acetate kinase and of the aceA and aceB genes coding for the glyoxylate cycle enzymes isocitrate lyase and malate synthase, respectively. Deletion and mutation analysis of the respective promoter regions led to the identification of highly conserved 13-bp motifs (AA/GAACTTTGCAAA) as cis-regulatory elements for expression of the pta-ack operon and the aceA and aceB genes. By use of DNA affinity chromatography, a 53-kDa protein specifically binding to the promoter/operator region of the pta-ack operon was purified. Mass spectrometry and peptide mass fingerprinting identified the protein as a putative transcriptional regulator (which was designated RamB). Purified His-tagged RamB protein was shown to bind specifically to both the pta-ack and the aceA/aceB promoter/operator regions. Directed deletion of the ramB gene in the genome of C. glutamicum resulted in mutant strain RG1. Whereas the wild type of C. glutamicum showed high-level specific activities of acetate kinase, phosphotransacetylase, isocitrate lyase, and malate synthase when grown on acetate and low-level specific activities when grown on glucose as sole carbon and energy sources, mutant RG1 showed high-level specific activities with all four enzymes irrespective of the substrate. Comparative transcriptional cat fusion experiments revealed that this deregulation takes place at the level of transcription. The results indicate that RamB is a negative transcriptional regulator of genes involved in acetate metabolism of C. glutamicum.

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.

scholarly journals The carbonate concentration mechanism of Pyropia yezoensis (Rhodophyta): evidence from transcriptomics and biochemical data

2020 ◽  
Vol 20 (1) ◽  
Author(s):  
Baoyu Zhang ◽  
Xiujun Xie ◽  
Xuehua Liu ◽  
Linwen He ◽  
Yuanyuan Sun ◽  
...  
Keyword(s):  
Photosynthetic Efficiency ◽  
Inorganic Carbon ◽  
De Novo ◽  
Isocitrate Lyase ◽  
Life Cycles ◽  
Malate Synthase ◽  
Pyropia Yezoensis ◽  
Cdna Libraries ◽  
Life Stages ◽  
Low Carbon

Abstract Background Pyropia yezoensis (Rhodophyta) is widely cultivated in East Asia and plays important economic, ecological and research roles. Although inorganic carbon utilization of P. yezoensis has been investigated from a physiological aspect, the carbon concentration mechanism (CCM) of P. yezoensis remains unclear. To explore the CCM of P. yezoensis, especially during its different life stages, we tracked changes in the transcriptome, photosynthetic efficiency and in key enzyme activities under different inorganic carbon concentrations. Results Photosynthetic efficiency demonstrated that sporophytes were more sensitive to low carbon (LC) than gametophytes, with increased photosynthesis rate during both life stages under high carbon (HC) compared to normal carbon (NC) conditions. The amount of starch and number of plastoglobuli in cells corresponded with the growth reaction to different inorganic carbon (Ci) concentrations. We constructed 18 cDNA libraries from 18 samples (three biological replicates per Ci treatment at two life cycles stages) and sequenced these using the Illumina platform. De novo assembly generated 182,564 unigenes, including approximately 275 unigenes related to CCM. Most genes encoding internal carbonic anhydrase (CA) and bicarbonate transporters involved in the biophysical CCM pathway were induced under LC in comparison with NC, with transcript abundance of some PyCAs in gametophytes typically higher than that in sporophytes. We identified all key genes participating in the C4 pathway and showed that their RNA abundances changed with varying Ci conditions. High decarboxylating activity of PEPCKase and low PEPCase activity were observed in P. yezoensis. Activities of other key enzymes involved in the C4-like pathway were higher under HC than under the other two conditions. Pyruvate carboxylase (PYC) showed higher carboxylation activity than PEPC under these Ci conditions. Isocitrate lyase (ICL) showed high activity, but the activity of malate synthase (MS) was very low. Conclusion We elucidated the CCM of P. yezoensis from transcriptome and enzyme activity levels. All results indicated at least two types of CCM in P. yezoensis, one involving CA and an anion exchanger (transporter), and a second, C4-like pathway belonging to the PEPCK subtype. PYC may play the main carboxylation role in this C4-like pathway, which functions in both the sporophyte and gametophyte life cycles.

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