The inhibitory effect of the amino acid complexes of Zn(II) on the growth of Aspergillus flavus and aflatoxin B1 production

AIM: In this study, we evaluated the effect of silver nanoparticles (AgNPs) on the production of aflatoxin B1 (AFB1) through assessment the transcription activity of aflatoxin biosynthesis pathway genes in Aspergillus flavus ATCC28542.MATERIAL AND METHODS: The mRNAs were quantitative by Real Time-polymerase chain reaction (qRT-PCR) of A. flavus grown in yeast extract sucrose (YES) medium containing AgNPs. Specific primers that are involved in the AFB1 biosynthesis which highly specific to A. flavus, O-methyltransferase gene (omt-A), were designed and used to detect the fungus activity by quantitative PCR assay. The AFB1 production (from A. flavus growth) which effected by AgNPs were measured in YES medium by high-pressure liquid chromatography (HPLC).RESULTS: The AFB1 produced by A. flavus have the highest reduction with 1.5 mg -100 ml of AgNPs were added in media those records 88.2%, 67.7% and 83.5% reduction by using AgNP HA1N, AgNP HA2N and AgNP EH, respectively. While on mycelial growth give significantly inhibitory effect. These results have been confirmed by qRT-PCR which showed that culture of A. flavus with the presence of AgNPs reduced the expression levels of omt-A gene.CONCLUSION: Based on the results of the present study, AgNPs inhibit growth and AFB1 produced by Aspergillus flavus ATCC28542. This was confirmed through RT-PCR approach showing the effect of AgNPs on omt-A gene involved in aflatoxin biosynthesis.

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Dimethylformamide Inhibits Fungal Growth and Aflatoxin B1 Biosynthesis in Aspergillus flavus by Down-Regulating Glucose Metabolism and Amino Acid Biosynthesis

Toxins ◽

10.3390/toxins12110683 ◽

2020 ◽

Vol 12 (11) ◽

pp. 683

Author(s):

Lin Pan ◽

Peng Chang ◽

Jing Jin ◽

Qingli Yang ◽

Fuguo Xing

Keyword(s):

Amino Acid ◽

Glucose Metabolism ◽

Aflatoxin B1 ◽

Fungal Pathogens ◽

Fungal Growth ◽

Inhibitory Effect ◽

Amino Acid Biosynthesis ◽

Inhibition Mechanism ◽

Rna Seq ◽

Acid Biosynthesis

Aflatoxins (AFs) are secondary metabolites produced by plant fungal pathogens infecting crops with strong carcinogenic and mutagenic properties. Dimethylformamide (DMF) is an excellent solvent widely used in biology, medicine and other fields. However, the effect and mechanism of DMF as a common organic solvent against fungal growth and AFs production are not clear. Here, we discovered that DMF had obvious inhibitory effect against A. flavus, as well as displayed complete strong capacity to combat AFs production. Hereafter, the inhibition mechanism of DMF act on AFs production was revealed by the transcriptional expression analysis of genes referred to AFs biosynthesis. With 1% DMF treatment, two positive regulatory genes of AFs biosynthetic pathway aflS and aflR were down-regulated, leading to the suppression of the structural genes in AFs cluster like aflW, aflP. These changes may be due to the suppression of VeA and the subsequent up-regulation of FluG. Exposure to DMF caused the damage of cell wall and the dysfunction of mitochondria. In particular, it is worth noting that most amino acid biosynthesis and glucose metabolism pathway were down-regulated by 1% DMF using Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis. Taken together, these RNA-Seq data strongly suggest that DMF inhibits fungal growth and aflatoxin B1 (AFB1) production by A. flavus via the synergistic interference of glucose metabolism, amino acid biosynthesis and oxidative phosphorylation.

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Glufosinate-Ammonium Reduces Growth and Aflatoxin B1 Production by Aspergillus flavus

Journal of Food Protection ◽

10.4315/0362-028x-65.9.1483 ◽

2002 ◽

Vol 65 (9) ◽

pp. 1483-1487 ◽

Cited By ~ 11

Author(s):

K. M. TUBAJIKA ◽

K. E. DAMANN

Keyword(s):

Seed Germination ◽

Aspergillus Flavus ◽

Aflatoxin B1 ◽

Dry Weight ◽

Inhibitory Effect ◽

Butanoic Acid ◽

Screening Assay ◽

Glufosinate Ammonium ◽

Colony Diameter ◽

Mycotoxigenic Fungus

The herbicide glufosinate-ammonium (GA) [butanoic acid, 2-amino-4-(hydroxymethylphosphinyl)-ammonium salt] was tested at concentrations from 2 to 2,000 g GA per ml for activity against growth and aflatoxin B1 (AFB1) production by the mycotoxigenic fungus Aspergillus flavus Link:Fr. The highest concentration (2,000 μg GA per ml) reduced colony diameter of A. flavus strain AF13 by 80%. AFB1 production was inhibited by 90% at this concentration. Reduction in mycelial dry weight and AFB1 production in response to GA application ranged from 17.2 to 97.1% and from 39.1 to 90.1%, respectively. Of four concentrations tested, 2 μg GA per ml was weakly inhibitory. In the kernel screening assay, AFB1 production was inhibited 60 to 91% when kernels were preimmersed or immersed 5 days after incubation in 200 μg GA per ml. Both concentrations (2 and 200 μg GA per ml) reduced seed germination by 25 to 50%. Results indicate that GA has an inhibitory effect on growth and AFB1 production by A. flavus.

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AKTIVITAS ANTIAFLATOKSIN B1 EKSTRAK DAUN RUMPUT KEBAR (Biophytum petersianum) TERHADAP Aspergillus ﬂavus (Antiaﬂatoxin B1 Activity of Kebar Grass (Biophytum petersianum) Leaf Extract on Aspergillus ﬂavus)

Jurnal Agritech ◽

10.22146/agritech.9414 ◽

2015 ◽

Vol 35 (01) ◽

pp. 9

Author(s):

Meike Meilan Lisangan ◽

Rizal Syarie ◽

Winiati Pudji Rahayu ◽

Okky Setyawati Dharmaputra

Keyword(s):

Aspergillus Flavus ◽

Aflatoxin B1 ◽

Leaf Extract ◽

Inhibitory Effect ◽

Leaf Extracts ◽

Model Medium ◽

Biophytum Petersianum ◽

Negative Effect ◽

Food Model ◽

Different Levels

Aﬂatoxin B1 was a secondary metabolite produced by Aspergillus ﬂavus having negative effect on human health because of its carcinogenic. Many efforts have been done to investigate the antifungal and antiaﬂatoxin agent derived plant. The objective of this research was to study the activity of antifungal from kebar grass leaf extract on mycelial growth and aﬂatoxin B1 production of Aspergillus ﬂavus BCC F0219 and A. ﬂavus BIO 2236 isolates in food model medium i.e. carbohydrate-enriched medium, fat-enriched medium and protein-enriched medium. Kebar grass leaf extracts was successively obtained by using n-hexane - ethyl acetate - methanol (HEM). Concentrations of the extract tested on A. ﬂavus BCC F0219 and A. ﬂavus BIO 2236 were 1; 1.5, and 2 MIC. The MIC for A. ﬂavus BCC F0219 in carbohydrate-enriched medium, fat-enriched medium, and protein-enriched medium were 12, 14, and 14 mg/mL, respectively. Meanwhile, the MIC for A. ﬂavus BIO 2236 in carbohydrate-enriched medium, fat-enriched medium and protein-enriched medium were 12, 16 and 16 mg/mL, respectively. The results showed that the percentage of growth inhibition of A. ﬂavus BCC F0219 and BIO 2236 in carbohydrate, fat and protein-enriched medium at 3 different levels of MIC concentrations ranged between 90.8 - 100% and 93.8 - 100%. The inhibitory effect of Aﬂatoxin B1 production of A. ﬂavus F0219 BCC and BIO 2236 in carbohydrate, fat and protein-enriched medium at 3 different levels of MIC concentration ranged between 70.86 - 100 % and 83.42 – 98.84 %.Keywords: Aﬂatoxin B1, anti aﬂatoxin, Aspergillus ﬂavus, Biophytum petersianum, food model medium, kebar grass ABSTRAKAflatoksin B1 merupakan metabolit sekunder yang dihasilkan oleh Aspergillus ﬂavus yang berbahaya bagi kesehatan karena bersifat karsinogenik. Berbagai upaya telah dilakukan untuk mencari bahan antikapang dan antiaﬂatoksin yang berasal dari bahan alami seperti tumbuhan. Tujuan penelitian ini adalah mempelajari aktivitas ekstrak daun rumput kebar terhadap pertumbuhan miselium dan produksi aﬂatoksin B1 dari isolat A. ﬂavus BC F0219 dan A. ﬂavus BIO2236 pada media model pangan kaya karbohidrat, lemak dan protein. Ekstrak daun rumput kebar diekstraksi secara bertingkat dengan pelarut n-heksana-etil asetat-metanol (HEM). Konsentrasi ekstrak yang diuji untuk isolatA. ﬂavus BCC F0219 dan A. ﬂavus BIO 2236 masing-masing adalah 1; 1,5; dan 2 MIC (Minimum Inhibitory Concentration).NilaiMIC untuk A. ﬂavus BCC F0219 pada media kaya karbohidrat, lemak, dan protein berturut-turut sebesar 12, 14, dan 14 mg/mL. Sedangkan nilai MIC untuk A. ﬂavus BIO 2236 pada media kaya karbohidrat, lemak, dan protein berturutturut sebesar 12, 16, dan 16 mg/mL. Hasil pengujian memperlihatkan bahwa persentase hambatan pertumbuhan isolat A.ﬂavus BCC F0219 dan BIO 2236 pada media kaya karbohidrat, lemak dan protein pada 3 tingkat konsentrasi MIC berkisar antara 90,8 – 100% dan 93,8 – 100%. Hambatan produksi aﬂatoksin B1 isolat A. ﬂavus BCC F0219 dan BIO 2236pada media kaya karbohidrat, lemak dan protein pada 3 tingkat konsentrasi MIC berkisar antara 70,86 – 100% dan 83,42 – 98,84%.Kata kunci: Aﬂatoxin B1, anti aﬂatoksin, Aspergillus ﬂavus, Biophytum petersianum, media model pangan, rumput kebar

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Purification and Characterization of Lupus Anticoagulant Like Protein from Agkistrodon Halys Brevicaudus Venom

Thrombosis and Haemostasis ◽

10.1055/s-0038-1650698 ◽

1996 ◽

Vol 76 (06) ◽

pp. 0993-0997

Author(s):

Zhao-Yan Li ◽

Xiao-Wei Wu ◽

Tie-Fu Yu ◽

Eric C-Y Lian

Keyword(s):

Amino Acid ◽

Lupus Anticoagulant ◽

Inhibitory Effect ◽

Clotting Factor ◽

Acid Oxidase ◽

Crude Venom ◽

Amino Acid Oxidase ◽

Sds Page ◽

The Individual ◽

Reducing Condition

SummaryBy means of CM-Sephadex C-25, DEAE-Sephadex A-50, Sephadex G-200, and Sephadex G-75 chromatographies, a lupus anticoagulant like protein (LALP) from Agkistrodon halys brevicaudus was purified. On SDS-PAGE, the purified LALP had a molecular weight of 25,500 daltons under non-reducing condition and 15,000 daltons under reducing condition. The isoelectric point was pH 5.6. Its N terminal amino acid sequencing revealed a mixture of 2 sequences: DCP(P/S)(D/G)WSSYEGH(C/R)Q(Q/K). It was devoid of phospho-lipaseA, fibrino(geno)lytic, 5′-nucleotidase, L-amino acid oxidase, phosphomonoesterase, phosphodiesterase and thrombin-like activities, which were found in crude venom. In the presence of LALP, PT, aPTT, and dRVVT of human plasma were markedly prolonged and its effects were concentration-dependent but time-independent. The inhibitory effect of LALP on the plasma clotting time was enhanced by decreasing phospholipid concentration in TTI test. The individual clotting factor activity was not affected by LALP when higher dilutions of LALP-plasma mixture were used for assay. Russell’s viper venom time was shortened when high phospholipid confirmatory reagent was used. Therefore, the protein has lupus anticoagulant property.

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Potentiometric study of enantioselective effects in α-amino acid complexes of copper(II)

Inorganica Chimica Acta ◽

10.1016/s0020-1693(00)83787-1 ◽

1985 ◽

Vol 104 (1) ◽

pp. 63-67 ◽

Cited By ~ 6

Author(s):

I.L. Ulanovski ◽

A.A. Kurganov ◽

V.A. Davankov

Keyword(s):

Amino Acid ◽

Potentiometric Study ◽

Amino Acid Complexes

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Mimosa tenuiflora Aqueous Extract: Role of Condensed Tannins in Anti-Aflatoxin B1 Activity in Aspergillus flavus

Toxins ◽

10.3390/toxins13060391 ◽

2021 ◽

Vol 13 (6) ◽

pp. 391

Author(s):

Christopher Hernandez ◽

Laura Cadenillas ◽

Anwar El Maghubi ◽

Isaura Caceres ◽

Vanessa Durrieu ◽

...

Keyword(s):

Aspergillus Flavus ◽

Aqueous Extract ◽

Aflatoxin B1 ◽

Condensed Tannins ◽

Fungal Growth ◽

Oxidation Reactions ◽

Expression Of Genes ◽

Dependent Inhibition ◽

Interesting Candidate ◽

Mimosa Tenuiflora

Aflatoxin B1 (AFB1) is a potent carcinogenic mycotoxin that contaminates numerous crops pre- and post-harvest. To protect foods and feeds from such toxins without resorting to pesticides, the use of plant extracts has been increasingly studied. The most interesting candidate plants are those with strong antioxidative activity because oxidation reactions may interfere with AFB1 production. The present study investigates how an aqueous extract of Mimosa tenuiflora bark affects both the growth of Aspergillus flavus and AFB1 production. The results reveal a dose-dependent inhibition of toxin synthesis with no impact on fungal growth. AFB1 inhibition is related to a down-modulation of the cluster genes of the biosynthetic pathway and especially to the two internal regulators aflR and aflS. Its strong anti-oxidative activity also allows the aqueous extract to modulate the expression of genes involved in fungal oxidative-stress response, such as msnA, mtfA, atfA, or sod1. Finally, a bio-guided fractionation of the aqueous extract demonstrates that condensed tannins play a major role in the anti-aflatoxin activity of Mimosa tenuiflora bark.

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Impacts of Climate Change Interacting Abiotic Factors on Growth, aflD and aflR Gene Expression and Aflatoxin B1 Production by Aspergillus flavus Strains In Vitro and on Pistachio Nuts

Toxins ◽

10.3390/toxins13060385 ◽

2021 ◽

Vol 13 (6) ◽

pp. 385

Author(s):

Alaa Baazeem ◽

Alicia Rodriguez ◽

Angel Medina ◽

Naresh Magan

Keyword(s):

Climate Change ◽

Gene Expression ◽

Water Stress ◽

Aspergillus Flavus ◽

Aflatoxin B1 ◽

Abiotic Factors ◽

Pistachio Nuts ◽

Significant Difference ◽

Spoilage Fungi

Pistachio nuts are an important economic tree nut crop which is used directly or processed for many food-related activities. They can become colonized by mycotoxigenic spoilage fungi, especially Aspergillus flavus, mainly resulting in contamination with aflatoxins (AFs), especially aflatoxin B1 (AFB1). The prevailing climate in which these crops are grown changes as temperature and atmospheric CO2 levels increase, and episodes of extreme wet/dry cycles occur due to human industrial activity. The objectives of this study were to evaluate the effect of interacting Climate Change (CC)-related abiotic factors of temperature (35 vs. 37 °C), CO2 (400 vs. 1000 ppm), and water stress (0.98–0.93 water activity, aw) on (a) growth (b) aflD and aflR biosynthetic gene expression and (c) AFB1 production by two strains A. flavus (AB3, AB10) in vitro on milled pistachio-based media and when colonizing layers of shelled raw pistachio nuts. The A. flavus strains were resilient in terms of growth on pistachio-based media and the colonisation of pistachio nuts with no significant difference when exposed to the interacting three-way climate-related abiotic factors. However, in vitro studies showed that AFB1 production was significantly stimulated (p < 0.05), especially when exposed to 1000 ppm CO2 at 0.98–0.95 aw and 35 °C, and sometimes in the 37 °C treatment group at 0.98 aw. The relative expression of the structural aflD gene involved in AFB1 biosynthesis was decreased or only slightly increased, relative to the control conditions at elevated CO, regardless of the aw level examined. For the regulatory aflR gene expression, there was a significant (p < 0.05) increase in 1000 ppm CO2 and 37 °C for both strains, especially at 0.95 aw. The in situ colonization of pistachio nuts resulted in a significant (p < 0.05) stimulation of AFB1 production at 35 °C and 1000 ppm CO2 for both strains, especially at 0.98 aw. At 37 °C, AFB1 production was either decreased, in strain AB3, or remained similar, as in strain AB10, when exposed to 1000 ppm CO2. This suggests that CC factors may have a differential effect, depending on the interacting conditions of temperature, exposure to CO2 and the level of water stress on AFB1 production.

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Synthesis, Characterization, and Non-Covalent Interactions of Palladium(II)-Amino Acid Complexes

Molecules ◽

10.3390/molecules26144331 ◽

2021 ◽

Vol 26 (14) ◽

pp. 4331

Author(s):

David B. Hobart ◽

Michael A. G. Berg ◽

Hannah M. Rogers ◽

Joseph S. Merola

Keyword(s):

Amino Acid ◽

High Resolution Mass Spectrometry ◽

Resonance Spectroscopy ◽

Spectroscopic Techniques ◽

X Ray Diffraction ◽

Amino Acid Complexes ◽

Acetone Water ◽

Square Planar ◽

Non Covalent Interactions ◽

Covalent Interactions

The reaction of palladium(II) acetate with acyclic amino acids in acetone/water yields square planar bis-chelated palladium amino acid complexes that exhibit interesting non-covalent interactions. In all cases, complexes were examined by multiple spectroscopic techniques, especially HRMS (high resolution mass spectrometry), IR (infrared spectroscopy), and 1H NMR (nuclear magnetic resonance) spectroscopy. In some cases, suitable crystals for single crystal X-ray diffraction were able to be grown and the molecular structure was obtained. The molecular geometries of the products are discussed. Except for the alanine complex, all complexes incorporate water molecules into the extended lattice and exhibit N-H···O and/or O···(HOH)···O hydrogen bonding interactions. The non-covalent interactions are discussed in terms of the extended lattice structures exhibited by the structures.

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