scholarly journals Generation and Phenotypic Characterization of Aspergillus nidulans Methylisocitrate Lyase Deletion Mutants: Methylisocitrate Inhibits Growth and Conidiation

2005 ◽  
Vol 71 (9) ◽  
pp. 5465-5475 ◽  
Author(s):  
Matthias Brock
Keyword(s):  
Carbon Source ◽  
Aspergillus Nidulans ◽  
Isocitrate Dehydrogenase ◽  
Genomic Sequence ◽  
Competitive Inhibition ◽  
Carbon Sources ◽  
Inhibitory Effect ◽  
Phenotypic Characterization ◽  
Deletion Mutants ◽  
Main Carbon Source

ABSTRACT Propionate is a very abundant carbon source in soil, and many microorganisms are able to use this as the sole carbon source. Nevertheless, propionate not only serves as a carbon source for filamentous fungi but also acts as a preservative when added to glucose containing media. To solve this contradiction between carbon source and preservative effect, propionate metabolism of Aspergillus nidulans was studied and revealed the methylcitrate cycle as the responsible pathway. Methylisocitrate lyase is one of the key enzymes of that cycle. It catalyzes the cleavage of methylisocitrate into succinate and pyruvate and completes the α-oxidation of propionate. Previously, methylisocitrate lyase was shown to be highly specific for the substrate (2R,3S)-2-methylisocitrate. Here, the identification of the genomic sequence of the corresponding gene and the generation of deletion mutants is reported. Deletion mutants did not grow on propionate as sole carbon and energy source and were severely inhibited during growth on alternative carbon sources, when propionate was present. The strongest inhibitory effect was observed, when glycerol was the main carbon source, followed by glucose and acetate. In addition, asexual conidiation was strongly impaired in the presence of propionate. These effects might be caused by competitive inhibition of the NADP-dependent isocitrate dehydrogenase, because the Ki of (2R,3S)-2-methylisocitrate, the product of the methylcitrate cycle, on NADP-dependent isocitrate dehydrogenase was determined as 1.55 μM. Other isomers had no effect on enzymatic activity. Therefore, methylisocitrate was identified as a potential toxic compound for cellular metabolism.

Inhibition of Yeast Growth by Tryptamine and Recovery with Tryptophan

2020 ◽  
Vol 16 (1) ◽  
pp. 48-52 ◽  
Author(s):  
Chandrika Kadkol ◽  
Ian Macreadie
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Carbon Source ◽  
Competitive Inhibition ◽  
Yeast Species ◽  
Inhibitory Effect ◽  
The Body ◽  
Inhibitory Effects ◽  
Trna Synthetases ◽  
Fermentative Growth ◽  
Biogenic Monoamine

Background: Tryptamine, a biogenic monoamine that is present in trace levels in the mammalian central nervous system, has probable roles as a neurotransmitter and/or a neuromodulator and may be associated with various neuropsychiatric disorders. One of the ways tryptamine may affect the body is by the competitive inhibition of the attachment of tryptophan to tryptophanyl tRNA synthetases. Methods: This study has explored the effects of tryptamine on growth of six yeast species (Saccharomyces cerevisiae, Candida glabrata, C. krusei, C. dubliniensis, C. tropicalis and C. lusitaniae) in media with glucose or ethanol as the carbon source, as well as recovery of growth inhibition by the addition of tryptophan. Results: Tryptamine was found to have an inhibitory effect on respiratory growth of all yeast species when grown with ethanol as the carbon source. Tryptamine also inhibited fermentative growth of Saccharomyces cerevisiae, C. krusei and C. tropicalis with glucose as the carbon source. In most cases the inhibitory effects were reduced by added tryptophan. Conclusion: The results obtained in this study are consistent with tryptamine competing with tryptophan to bind mitochondrial and cytoplasmic tryptophanyl tRNA synthetases in yeast: effects on mitochondrial and cytoplasmic protein synthesis can be studied as a function of growth with glucose or ethanol as a carbon source. Of the yeast species tested, there is variation in the sensitivity to tryptamine and the rescue by tryptophan. The current study suggests appropriate yeast strains and approaches for further studies.

scholarly journals Regulation of the acuF Gene, Encoding Phosphoenolpyruvate Carboxykinase in the Filamentous Fungus Aspergillus nidulans

2002 ◽  
Vol 184 (1) ◽  
pp. 183-190 ◽  
Author(s):  
Michael J. Hynes ◽  
Oliver W. Draht ◽  
Meryl A. Davis
Keyword(s):  
Carbon Source ◽  
Aspergillus Nidulans ◽  
Phosphoenolpyruvate Carboxykinase ◽  
Carbon Sources ◽  
Tca Cycle ◽  
Northern Blotting ◽  
Gene Encoding ◽  
The Tca Cycle ◽  
Key Enzyme ◽  
Acetate Utilization

ABSTRACT Phosphoenolpyruvate carboxykinase (PEPCK) is a key enzyme required for gluconeogenesis when microorganisms grow on carbon sources metabolized via the tricarboxylic acid (TCA) cycle. Aspergillus nidulans acuF mutants isolated by their inability to use acetate as a carbon source specifically lack PEPCK. The acuF gene has been cloned and shown to encode a protein with high similarity to PEPCK from bacteria, plants, and fungi. The regulation of acuF expression has been studied by Northern blotting and by the construction of lacZ fusion reporters. Induction by acetate is abolished in mutants unable to metabolize acetate via the TCA cycle, and induction by amino acids metabolized via 2-oxoglutarate is lost in mutants unable to form 2-oxoglutarate. Induction by acetate and proline is not additive, consistent with a single mechanism of induction. Malate and succinate result in induction, and it is proposed that PEPCK is controlled by a novel mechanism of induction by a TCA cycle intermediate or derivative, thereby allowing gluconeogenesis to occur during growth on any carbon source metabolized via the TCA cycle. It has been shown that the facB gene, which mediates acetate induction of enzymes specifically required for acetate utilization, is not directly involved in PEPCK induction. This is in contrast to Saccharomyces cerevisiae, where Cat8p and Sip4p, homologs of FacB, regulate PEPCK as well as the expression of other genes necessary for growth on nonfermentable carbon sources in response to the carbon source present. This difference in the control of gluconeogenesis reflects the ability of A. nidulans and other filamentous fungi to use a wide variety of carbon sources in comparison with S. cerevisiae. The acuF gene was also found to be subject to activation by the CCAAT binding protein AnCF, a protein homologous to the S. cerevisiae Hap complex and the mammalian NFY complex.

Isolation and characterization of a heterotrophic nitrifier from coke plant wastewater

2012 ◽  
Vol 65 (11) ◽  
pp. 2084-2090 ◽  
Author(s):  
YuXiang Liu ◽  
YaQing Li ◽  
YongKang Lv
Keyword(s):  
Wastewater Treatment ◽  
Carbon Source ◽  
Coke Plant ◽  
Carbon Sources ◽  
Treatment Plant ◽  
Inhibitory Effect ◽  
Nitrite Accumulation ◽  
Meat Extract ◽  
Ammonium Removal ◽  
Isolation And Characterization

This study investigated some factors affecting ammonium removal and nitrite accumulation by Alcaligenes faecalis C16, which was isolated from the activated sludge of a coking wastewater treatment plant. Nitrite was produced from ammonium only in the presence of citrate, acetate, meat extract, peptone or ethanol. The highest amount of nitrite was found with citrate as carbon source. A. faecalis C16 could not use glucose, fructose, sucrose and methanol. Under the optimum conditions of initial pH 6.0, C/N 14, 30 °C and 120 rpm, a maximum nitrite accumulation of 28.29 mg/L NO2−-N was achieved when the organism grew with citrate in four days. Nitrite accumulation increased with the increase of NH4+-N. Furthermore, A. faecalis C16 was shown to have phenol-degrading capacity during ammonium removal. Metabolism of phenol resulted in acidification of the media, which is not favorable for nitrification, whereas many other carbon sources made the medium more alkaline. However, no inhibitory effect by phenol was observed when phenol and acetate were used as mixed carbon source at different phenol/sodium acetate (P/S) ratios and their pH values were all controlled above 9.2 or P/S ratios below 5:5. These results suggested that A. faecalis C16 has some potential application in industrial wastewater treatment systems.

scholarly journals ANME-2d anaerobic methanotrophic archaea differ from other ANME archaea in lipid composition and carbon source

2019 ◽  
Author(s):  
Julia M. Kurth ◽  
Nadine T. Smit ◽  
Stefanie Berger ◽  
Stefan Schouten ◽  
Mike S.M. Jetten ◽  
...  
Keyword(s):  
Carbon Source ◽  
Lipid Composition ◽  
Dissolved Inorganic Carbon ◽  
Carbon Sources ◽  
Freshwater Ecosystems ◽  
Anaerobic Oxidation Of Methane ◽  
Marine Environments ◽  
Sulfate Reducing ◽  
Oxidation Of Methane ◽  
Main Carbon Source

AbstractThe anaerobic oxidation of methane (AOM) is a microbial process present in marine and freshwater environments. AOM is important for reducing the emission of the second most important greenhouse gas methane. In marine environments anaerobic methanotrophic archaea (ANME) are involved in sulfate-reducing AOM. In contrast,Ca. Methanoperedens of the ANME-2d cluster carries out nitrate AOM in freshwater ecosystems. Despite the importance of those organisms for AOM in non-marine environments not much is known about their lipid composition or carbon sources. To close this gap, we analyzed the lipid composition of ANME-2d archaea and found that they mainly synthesize archaeol and hydroxyarchaeol as well as different (hydroxy-) glycerol dialkyl glycerol tetraethers, albeit in much lower amounts. Abundant lipid headgroups were dihexose, monomethyl-phosphatidyl ethanolamine and phosphatidyl hexose. Moreover, a monopentose was detected as a lipid headgroup which is rare among microorganisms. Batch incubations with13C labelled bicarbonate and methane showed that methane is the main carbon source of ANME-2d archaea varying from ANME-1 archaea which primarily assimilate dissolved inorganic carbon (DIC). ANME-2d archaea also assimilate DIC, but to a lower extent than methane. The lipid characterization and analysis of the carbon source ofCa.Methanoperedens facilitates distinction between ANME-2d and other ANMEs.

scholarly journals Anaerobic methanotrophic archaea of the ANME-2d clade feature lipid composition that differs from other ANME archaea

2019 ◽  
Vol 95 (7) ◽  
Author(s):  
Julia M Kurth ◽  
Nadine T Smit ◽  
Stefanie Berger ◽  
Stefan Schouten ◽  
Mike S M Jetten ◽  
...  
Keyword(s):  
Carbon Source ◽  
Lipid Composition ◽  
Dissolved Inorganic Carbon ◽  
Carbon Sources ◽  
Freshwater Ecosystems ◽  
Anaerobic Oxidation Of Methane ◽  
Marine Environments ◽  
Sulfate Reducing ◽  
Oxidation Of Methane ◽  
Main Carbon Source

ABSTRACTThe anaerobic oxidation of methane (AOM) is a microbial process present in marine and freshwater environments. AOM is important for reducing the emission of the second most important greenhouse gas methane. In marine environments anaerobic methanotrophic archaea (ANME) are involved in sulfate-reducing AOM. In contrast, Ca. Methanoperedens of the ANME-2d cluster carries out nitrate AOM in freshwater ecosystems. Despite the importance of those organisms for AOM in non-marine environments little is known about their lipid composition or carbon sources. To close this gap, we analysed the lipid composition of ANME-2d archaea and found that they mainly synthesise archaeol and hydroxyarchaeol as well as different (hydroxy-) glycerol dialkyl glycerol tetraethers, albeit in much lower amounts. Abundant lipid headgroups were dihexose, monomethyl-phosphatidyl ethanolamine and phosphatidyl hexose. Moreover, a monopentose was detected as a lipid headgroup that is rare among microorganisms. Batch incubations with 13C labelled bicarbonate and methane showed that methane is the main carbon source of ANME-2d archaea varying from ANME-1 archaea that primarily assimilate dissolved inorganic carbon (DIC). ANME-2d archaea also assimilate DIC, but to a lower extent than methane. The lipid characterisation and analysis of the carbon source of Ca. Methanoperedens facilitates distinction between ANME-2d and other ANMEs.

scholarly journals Influence of Carbon, Nitrogen and Phosphorous Sources on Glucoamylase Production by Aspergillus awamori in Solid State Fermentation

2003 ◽  
Vol 58 (9-10) ◽  
pp. 708-712 ◽  
Author(s):  
Telma Elita Bertolin ◽  
Willibaldo Schmidell ◽  
Alfredo E. Maiorano ◽  
Janice Casara ◽  
Jorge A. V. Costa
Keyword(s):  
Solid State ◽  
Carbon Source ◽  
Solid State Fermentation ◽  
Carbon Sources ◽  
Aspergillus Awamori ◽  
Main Carbon Source ◽  
Nitrogen Phosphorus ◽  
Additional Carbon Source ◽  
Main Carbon ◽  
Glucoamylase Production

AbstractIt was the objective of the present study to increase the production of glucoamylase by Aspergillus awamori through solid state fermentation, using wheat bran as the main carbon source and (NH4)2SO4, urea, KH2PO4, glucose, maltose and starch as additional nitrogen, phosphorus, and carbon sources. The production of glucoamylase is strongly influenced by N and C sources. A 100% increase was observed when the (NH4)2SO4 was replaced by urea, with C/N = 4.8, using maltose as the additional carbon source. C/P ratios in a range of 5.1 to 28.7 did not induce glucoamylase production under the studied conditions.

Influence of carbon source on arylsulfatase derepression in Pseudomonas C12B

1982 ◽  
Vol 28 (4) ◽  
pp. 383-388
Author(s):  
J. W. Fitzgerald ◽  
J. T. Ash
Keyword(s):  
Carbon Source ◽  
Carbon Sources ◽  
Inhibitory Effect ◽  
Sulfur Source ◽  
Fold Reduction ◽  
Arylsulfatase Activity

Compared with growth on citrate, growth of Pseudomonas C12B with acetate as a carbon source resulted in approximately a four- to six-fold reduction in arylsulfatase activity irrespective of the sulfur source utilized to derepress arylsulfatase formation. Similarly, when O-acetyl-L-serine, oxaloacetate, malate, or α-ketoglutarate served as carbon sources in place of acetate, a reduction in arylsulfatase levels also occurred to varying degrees Trivial explanations for these results have been ruled out but efforts to provide an explanation for the inhibitory effect of acetate were unsuccessful. Some evidence suggests that growth on acetate may generate the formation of a substance which inactivates or irreversibly inhibits the enzyme.

scholarly journals The regulation of NADL-glutamate dehydrogenase inAspergillus nidulans

1974 ◽  
Vol 23 (1) ◽  
pp. 119-124 ◽  
Author(s):  
J. R. Kinghorn ◽  
J. A. Pateman
Keyword(s):  
Amino Acids ◽  
Linkage Group ◽  
Carbon Source ◽  
Glutamate Dehydrogenase ◽  
Aspergillus Nidulans ◽  
Dehydrogenase Activity ◽  
Carbon Sources ◽  
Wild Type ◽  
Group Iii ◽  
Glutamate Dehydrogenase Activity

SummaryWild-type cells ofAspergillus nidulanshave undetectable NADL-glutamate dehydrogenase activity when utilizing glucose and high levels of NADL-glutamate dehydrogenase when utilizing certain amino acids as sole carbon sources.A mutant, designatedgdhCl, has appreciable NAD-GDH activity when utilizing glucose as a carbon source. ThegdhC1mutation is semi-dominant and is located in linkage group III.

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