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.

Control of catalase and peroxidase biosynthesis by carbon source and oxygen in the yeast Saccharomyces cerevisiae

1983 ◽  
Vol 29 (9) ◽  
pp. 1200-1204 ◽  
Author(s):  
E. Valdivia ◽  
J. Martinez ◽  
J. M. Ortega ◽  
E. Montoya
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Carbon Source ◽  
Oxygen Tension ◽  
Aminolevulinic Acid ◽  
Inhibitory Effect ◽  
Enzymatic Activities ◽  
The Other ◽  
Prosthetic Group ◽  
Yeast Saccharomyces Cerevisiae ◽  
Direct Inhibitory Effect

The effect of carbon source and oxygen tension on catalase and peroxidase levels and on the intermediates of the biosynthesis of the prosthetic group of both enzymes has been studied. Oxygen produces an increase of both enzymatic activities, even in presence of glucose. On the other hand it seems probable that glucose does not have a direct inhibitory effect on the biosynthesis of 5-aminolevulinic acid (ALA) and porphyrins.

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.

scholarly journals Molecular basis for SPIN·DOC-Spindlin1 engagement and its role in transcriptional inhibition

2021 ◽  
Author(s):  
Fan Zhao ◽  
Fen Yang ◽  
Fan Feng ◽  
Bo Peng ◽  
Mark T. Bedford ◽  
...  
Keyword(s):  
Transcriptional Activation ◽  
Competitive Inhibition ◽  
Inhibitory Effect ◽  
Transcriptional Coactivator ◽  
Inhibitory Effects ◽  
Binding Studies ◽  
Transcriptional Inhibition ◽  
Aromatic Cage ◽  
Hydrophobic Motif ◽  
Qpcr Experiment

ABSTRACTSpindlin1 is a transcriptional coactivator with three Tudor-like domains, of which the first and second Tudors are engaged in histone methylation readout, while the function of the third Tudor is largely unknown. Recent studies revealed that the transcriptional co-activator activity of Spindlin1 could be attenuated by SPIN•DOC. Here we solved the crystal structure of SPIN•DOC-Spindlin1 complex, revealing that a hydrophobic motif, DOCpep3 (256-281), of SPIN•DOC interacts with Tudor 3 of Spindlin1 and completes its β-barrel fold. Massive hydrophobic contacts and hydrogen bonding interactions ensure a high affinity DOCpep3-Spindlin1 engagement with a binding Kd of 30 nM. Interestingly, we characterized two more K/R-rich motifs of SPIN•DOC, DOCpep1 (187-195) and DOCpep2 (228-239), which bind to Spindlin1 at lower affinities with Kd values of 78 μM and 31 μM, respectively. Structural and binding studies revealed that DOCpep1 and DOCpep2 competitively bind to the aromatic cage of Spindlin1 Tudor 2 that is responsible for H3K4me3 readout. Although DOCpep3-Spindlin1 engagement is compatible with histone readout, an extended SPIN•DOC fragment containing DOCpep1 and DOCpep2 inhibits histone or TCF4 binding by Spindin1 due to introduced competition. This inhibitory effect is more pronounced for weaker binding targets but not for strong ones such as H3 “K4me3-K9me3” bivalent mark. Our RT-qPCR experiment showed that the removal of the hydrophobic motif or the K/R-rich region compromised the inhibitory effects of SPIN•DOC on Spindlin1-mediated transcriptional activation. In sum, here we revealed multivalent engagement between SPIN•DOC and Spindlin1, in which a hydrophobic motif acts as the primary binding site for stable SPIN•DOC-Spindlin1 association, while two more neighboring K/R-rich motifs further modulate the target selectivity of Spindlin1 via competitive inhibition, therefore attenuating the transcriptional co-activator activities of Spindlin1 through affecting its chromatin association.

Selective aromatase inhibition by pyridoglutethimide, an analogue of aminoglutethimide

1990 ◽  
Vol 122 (5) ◽  
pp. 592-598 ◽  
Author(s):  
Jo Kitawaki ◽  
Takara Yamamoto ◽  
Mamoru Urabe ◽  
Takaya Tamura ◽  
Shigeo Inoue ◽  
...  
Keyword(s):  
Competitive Inhibition ◽  
Inhibitory Effect ◽  
Side Chain ◽  
Aromatase Activity ◽  
Inhibitory Effects ◽  
Metabolizing Enzymes ◽  
Chain Cleavage ◽  
Steroid Hydroxylases ◽  
Cytochrome P 450

Abstract. The inhibitory effects of pyridoglutethimide (3-ethyl-3-(4-pyridyl)piperidine-2,6-dione), an analogue of aminoglutethimide, on aromatase and other cytochrome P-450-dependent steroid-metabolizing enzymes were studied in vitro. Pyridoglutethimide and aminoglutethimide showed competitive inhibition of human placental aromatase activity with apparent Ki values of 1.7 and 0.7 μmol/l, respectively. Both pyridoglutethimide and aminoglutethimide inhibited the aromatase activity of uterine leiomyoma and cultured choriocarcinoma Enami cells as well as immunopurified human placental aromatase cytochrome P-450 by more than 90%, with IC50 values of 10–19 and 5–7 μmol/l, respectively. These results might suggest that the inhibitors interacted directly with the aromatase cytochrome P-450 of these tissues. Aminoglutethimide inhibited bovine adrenal cholesterol side-chain cleavage activity with an IC50 value of 40 μmol/l and inhibited 21-hydroxylase activity slightly, but did ot inhibit 17α-, 1 1β- and 18-hydroxylase at concentrations up to 100 μmol/l. On the other hand, pyridoglutethimide had no inhibitory effect on any of these enzymes at concentrations up to 50 μmol/l, although it inhibited 11β- and 18-hydroxylase slightly at 100 μmol/l. These results indicated that pyridoglutethimide was an aromatase inhibitor of a comparable potency to aminoglutethimide, but that it did not inhibit other steroid hydroxylases.

The Inhibitory Effect of Sialic Acid on Fibrinolysis

1967 ◽  
Vol 17 (01/02) ◽  
pp. 023-030 ◽  
Author(s):  
H Rubin ◽  
N. D Ritz
Keyword(s):  
Sialic Acid ◽  
Inhibitory Effect ◽  
Sialic Acids ◽  
Normal Serum ◽  
The Body ◽  
Inhibitory Effects ◽  
Acetylneuraminic Acid ◽  
Heated Plates ◽  
Hydrolysis Of ◽  
Fibrinolytic Action

SummaryThe inhibitory effect of N-acetylneuraminic acid and glycolyl neuramaminic acids on the hydrolysis of 51Cr tagged casein by plasmin and α-chymotrypsin has been demonstrated. N,O-diacetylneuraminic acid was ineffective. The inhibitory effect was increased by an increase in ionic strength of the reaction mixture. The two active sialic acids also inhibited the fibrinolytic action of human plasmin on heated and unheated bovine fibrin plates. The greater inhibition noted on heated plates may indicate a primary effect on plasmin rather than on activators of plasmin. The inhibitory effects of N-acetyl neuraminic acid appeared to be potentiated by normal serum inhibitors. Sialic acid did not influence the conversion of fibrin monomer to polymer.N-acetylneuraminic acid may play an important role in preserving the integrity of fibrin deposits in the body.

Effect of postgastric energy loads on intake of sham meals of different palatability in rats

1994 ◽  
Vol 267 (1) ◽  
pp. R150-R155 ◽  
Author(s):  
D. Rigaud ◽  
D. Betoulle ◽  
A. Chauvel ◽  
L. A. Alberto ◽  
M. Apfelbaum
Keyword(s):  
Food Intake ◽  
Energy Input ◽  
Inhibitory Effect ◽  
Liquid Diet ◽  
The Body ◽  
Nutrient Load ◽  
Inhibitory Effects ◽  
Sham Feeding ◽  
Intraduodenal Infusion ◽  
Sucrose Solutions

Food intake depends on the palatability of the diet and on the energy delivered to the body. It is not known, however, whether the palatability of a diet is able to modulate the inhibitory effect of energy input on food intake. To address this question, we have measured intake during sham feeding for diets of different palatabilities in rats receiving varying levels of duodenal energy load. Rats were offered sucrose solutions (6, 10, or 30%) or mixed liquid diets without or with physiological duodenal energy loads using a mixed liquid diet. Compared with that seen during real feeding, meal size during sham feeding was increased for palatable diets but not for less palatable diets. Intraduodenal infusion of the mixed liquid diet inhibited the intake of all diets given by sham feeding. This inhibition was dependent on the level of duodenal energy load and was significantly greater for more palatable diets than for less palatable ones. We conclude that the inhibitory effects of intestinal nutrient load on intake are significant for all diets but have a more pronounced effect on the intake of highly palatable diets.

scholarly journals Effects of thia-substituted fatty acids on mitochondrial and peroxisomal β-oxidation. Studies in vivo and in vitro

1990 ◽  
Vol 270 (1) ◽  
pp. 167-173 ◽  
Author(s):  
R Hovik ◽  
H Osmundsen ◽  
R Berge ◽  
A Aarsland ◽  
S Bergseth ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Competitive Inhibition ◽  
Inhibitory Effect ◽  
Inhibitory Effects ◽  
Duration Of Treatment ◽  
Acyl Coa Oxidase ◽  
Dose Dependent

1. The effects of 3-, 4- and 5-thia-substituted fatty acids on mitochondrial and peroxisomal β-oxidation have been investigated. When the sulphur atom is in the 4-position, the resulting thia-substituted fatty acid becomes a powerful inhibitor of β-oxidation. 2. This inhibition cannot be explained in terms of simple competitive inhibition, a phenomenon which characterizes the inhibitory effects of 3- and 5-thia-substituted fatty acids. The inhibitory sites for 4-thia-substituted fatty acids are most likely to be the acyl-CoA dehydrogenase in mitochondria and the acyl-CoA oxidase in peroxisomes. 3. The inhibitory effect of 4-thia-substituted fatty acids is expressed both in vitro and in vivo. The effect in vitro is instantaneous, with up to 95% inhibition of palmitoylcarnitine oxidation. The effect in vivo, in contrast, is dose-dependent and increases with duration of treatment. 4. Pretreatment of rats with a 3-thia-substituted fatty acid rendered mitochondrial β-oxidation less sensitive to inhibition by 4-thia-substituted fatty acids.

scholarly journals Inhibitory Effects of Eight Green Tea Catechins on Cytochrome P450 1A2, 2C9, 2D6, and 3A4 Activities

2016 ◽  
Vol 19 (2) ◽  
pp. 188 ◽  
Author(s):  
Takashi Satoh ◽  
Haruka Fujisawa ◽  
Ami Nakamura ◽  
Natsuko Takahashi ◽  
Kazuhiro Watanabe
Keyword(s):  
Cytochrome P450 ◽  
Green Tea ◽  
Competitive Inhibition ◽  
Liver Microsomes ◽  
Inhibitory Effect ◽  
Dietary Habit ◽  
Inhibitory Effects ◽  
Tea Catechins ◽  
Green Tea Catechins ◽  
High Concentrations

PURPOSE: Green tea is a traditional beverage that has been enjoyed by the Japanese to this day. Recently, there has been an increase in the consumption of green tea beverage having high concentrations of catechins, such as (-)-epigallocatechin-3-O-gallate (EGCG). Many people tend to ingest large amounts of catechins through the frequent consumption of green tea beverage, and this dietary habit may lead to unwanted interactions between the catechins in green tea and medicinal drug. METHODS: The inhibitory effects of eight green tea catechins on drug metabolizing enzymes, cytochrome P450 (CYP) 1A2, 2C9, 2D6, and 3A4, were investigated in human liver microsomes. Incubation was initiated by the addition of cocktail probe drugs that served as specific substrates for each CYP, and the resulting metabolites were analyzed by LC-MS. RESULTS: From a comparison of the fifty percent inhibitory concentration (IC50) values of the eight green tea catechins, it was found that non-gallated catechins did not inhibit CYPs, whereas gallated catechins inhibited all CYPs except CYP2D6. Among them, CYP2C9 was most strongly inhibited by (-)-catechin-3-O-gallate (CG) (7.60 µM), and CYP1A2 was most strongly inhibited by EGCG (8.93 µM). Catechin gallate exhibited non-competitive inhibition of CYP2C9, and its Ki value was 9.76 ± 0.47µM. The present study is the first to report the inhibitory effect of CG on CYP2C9. In contrast, EGCG showed competitive inhibition of CYP1A2, and its Ki value was 14.3 ± 0.09 µM. CONCLUSION: Previous reports had predicted that plasma EGCG concentration reached 7.4 µM after ingesting green tea having high concentrations of catechins. That concentration of EGCG is equivalent to one-half to one-third of its Ki value for CYP1A2 and CYP3A4 in this study. The ingestion of beverages containing large amounts of green tea catechins together with drugs that are metabolized by CYP1A2, CYP2C9, and CYP3A4 should be avoided. This article is open to POST-PUBLICATION REVIEW. Registered readers (see “For Readers”) may comment by clicking on ABSTRACT on the issue’s contents page.

Itanoxone, An Inhibitor Of Cyclo-Oxygenase, Acts Preferentially On Platelet Than On Vascular Enzyme

1981 ◽  
Author(s):  
S Villa ◽  
A DeLhon ◽  
C Palmier ◽  
M Livio ◽  
B Maynardier ◽  
...  
Keyword(s):  
Competitive Inhibition ◽  
Cumulative Effect ◽  
Inhibitory Effect ◽  
Prostaglandin Synthesis ◽  
Measurable Effect ◽  
Inhibitory Effects ◽  
Antithrombotic Drug ◽  
Repeated Doses ◽  
Dose Dependent ◽  
Potential Use

Several attaints have been made to dissociate the inhibitory effects of aspirin on platelet and vascular cells, but no definite results have been obtained. Other drugs, presumably acting on cyclo-oxygenase, are therefore being investigated for their relative inhibitory effect on platelet and vascular prostaglandin synthesis.The present study was performed in male CD-COBS rats. Itanoxone [ (chloro-2' -diphenyl) -4-oxo-4 methylene 2-butyric acid ], a newly developed, hypolipidemic and hypouricemic compound with moderate anti-inflanmatory activity, showed a short lived, dose dependent (20-200 mg/kg, orally) apparently competitive inhibition of platelet MDA stimulated by either thrombin or arachidonic acid. Repeated doses did not result in any cumulative effect. At doses which completely blocked MDA production, itanoxone also inhibited thrombin-stimulated thromboxane B2 production in platelets but had no measurable effect on vascular prostacyclin generation measured both by a bioassay and a radioimmunoassay of its stable derivative 6-Keto-PGF1α . Pretreatment with itanoxone partially prevented therrhibitory effect of aspirin on both platelet and vascular prostaglandin synthesis. This suggests that itanoxone - like aspirin - acts at the level of cyclo-oxygenase but has much greater selectivity on the platelet enzyme.This pharmacological activity is of great theoretical interest for potential use of this compound as an antithrombotic drug.

scholarly journals Potential Antidiabetic Effects of Extracts from Four Medicinal Plants Used in Burkina Faso by Inhibition of Alpha-Amylase

Diabetology ◽  
2021 ◽  
Vol 2 (4) ◽  
pp. 250-258
Author(s):  
Judith N. Semporé ◽  
Mamounata Diao ◽  
Lassina Ouattara ◽  
Paulin Ouoba ◽  
Windmi Kagambega ◽  
...  
Keyword(s):  
Plant Extracts ◽  
Competitive Inhibition ◽  
Inhibitory Effect ◽  
Rice Starch ◽  
Inhibitory Effects ◽  
Sclerocarya Birrea ◽  
Dependent Inhibition ◽  
Phytochemical Compounds ◽  
Dose Dependent Inhibition ◽  
Liquid Fractionation

Background: The purpose of this study was to evaluate α-amylase inhibitory effects of hydroethanolic extracts of bark from Daniella oliveri, Sclerocarya birrea, Maranthes polyandra, and Pteleopsis suberosa to fight type-II diabetes. Methods: Compound extractions were performed by hydroethanol maceration followed by liquid-liquid fractionation with solvents. TLC profiling was carried out with different fractions. The inhibitory effects of plant extracts on α-amylase activity were determined using rice starch as a substrate. Results: TLC profiling of different fractions showed different phytochemical compounds. The hydroethanolic plant extracts exhibited dose-dependent inhibition of α-amylase. D. oliveri displayed competitive inhibition, M. polyandra and S. birrea showed uncompetitive inhibition and Pteleopsis suberosa exerted mixed-inhibition. M. polyandra extract exerted the highest inhibitory effect (IC50 = 0.5 mg/mL). Conclusions: The barks of M. polyandra exhibit a remarkable α-amylase inhibitory effect which can be a novel source of antidiabetic molecules.

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