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1.
Anal Biochem ; 692: 115572, 2024 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-38777290

RESUMO

Deoxynivalenol (DON) is a common mycotoxin in food that mainly pollutes grain crops and feeds, such as barley, wheat and corn. DON has caused widespread concern in the field of food and feed safety. In this study, a colorimetric immunoassay was proposed based on the aggregation of gold nanoparticles (AuNPs) due to the decomposition of Mn2+ from gold-coated manganese dioxide (AuNP@MnO2) nanosheets. In this study, 2-(dihydrogen phosphate)-l-ascorbic acid (AAP) was hydrolyzed by alkaline phosphatase (ALP) and converted to ascorbic acid (AA). Then, AuNP@MnO2 was reduced to Mn2+ and AuNPs aggregation occurred. Using the unique optical characteristics of AuNPs and AuNP@MnO2, visible color changes realized simple detection of DON with high sensitivity and portability. With increasing DON content, the color changed more obviously. To quantitatively detect DON, pictures can be taken and the blue value can be read by a smartphone. The detection limit (Ic10) of this method was 0.098 ng mL-1, which was 326 times higher than that of traditional competitive ELISA, and the detection range was 0.177-6.073 ng mL-1. This method exhibited high specificity with no cross-reaction in other structural analogs. The average recovery rate of DON in corn flour samples was 89.1 %-110.2 %, demonstrating the high accuracy and stability of this assay in actual sample detection. Therefore, the colorimetric immunoassay can be used for DON-related food safety monitoring.


Assuntos
Colorimetria , Ouro , Manganês , Nanopartículas Metálicas , Smartphone , Tricotecenos , Colorimetria/métodos , Ouro/química , Tricotecenos/análise , Tricotecenos/química , Nanopartículas Metálicas/química , Imunoensaio/métodos , Manganês/química , Compostos de Manganês/química , Contaminação de Alimentos/análise , Óxidos/química , Limite de Detecção
2.
J Chem Inf Model ; 63(20): 6316-6331, 2023 10 23.
Artigo em Inglês | MEDLINE | ID: mdl-37821422

RESUMO

Trichothecenes are highly toxic mycotoxins produced by Fusarium fungi, while TRI101/201 family enzymes play a crucial role in detoxification through acetylation. Studies on the substrate specificity and catalytic kinetics of TRI101/201 have revealed distinct kinetic characteristics, with significant differences observed in catalytic efficiency toward deoxynivalenol, while the catalytic efficiency for T-2 toxin remains relatively consistent. In this study, we used structural bioinformatics analysis and a molecular dynamics simulation workflow to investigate the mechanism underlying the differential catalytic activity of TRI101/201. The findings revealed that the binding stability between trichothecenes and TRI101/201 hinges primarily on a hydrophobic cage structure within the binding site. An intrinsic disordered loop, termed loop cover, defined the evolutionary patterns of the TRI101/201 protein family that are categorized into four subfamilies (V1/V2/V3/M). Furthermore, the unique loop displayed different conformations among these subfamilies' structures, which served to disrupt (V1/V2/V3) or reinforce (M) the hydrophobic cages. The disrupted cages enhanced the water exposure of the hydrophilic moieties of substrates like deoxynivalenol and thereby hindered their binding to the catalytic sites of V-type enzymes. In contrast, this water exposure does not affect substrates like T-2 toxin, which have more hydrophobic substituents, resulting in a comparable catalytic efficiency of both V- and M-type enzymes. Overall, our studies provide theoretical support for understanding the catalytic mechanism of TRI101/201, which shows how an intrinsic disordered loop could impact the protein-ligand binding and suggests a direction for rational protein design in the future.


Assuntos
Toxina T-2 , Tricotecenos , Tricotecenos/química , Tricotecenos/metabolismo , Tricotecenos/toxicidade , Sítios de Ligação , Água
3.
Drug Metab Rev ; 54(3): 331-342, 2022 08.
Artigo em Inglês | MEDLINE | ID: mdl-35695207

RESUMO

Deoxynivalenol (DON) and its modified forms, including DON-3-glucoside (DON-3G), pose a major agricultural and food safety issue in the world. Their metabolites are relatively well-characterized; however, their metabolizing enzymes have not been fully explored. UDP-glucuronosyltransferases, 3-O-acetyltransferase, and glutathione S-transferase are involved in the formation of DON-glucuronides, 3-acetyl-DON, and DON-glutathione, respectively. There are interindividual differences in the metabolism of these toxins, including variation with respect to sex. Furthermore, interspecies differences in DON metabolism have been revealed, including differences in the major metabolites of DON, the role of de-acetylation, and the hydrolysis of DON-3G. In this review, we summarized the major enzymes involved in metabolizing DON to its modified forms, focusing on the differences in metabolism of DON and its modified forms between individuals and species. This work provides important insight into the toxicity of DON and its derivatives in humans and animals, and provides scientific basis for the development of safer and more efficient biological detoxification methods.


Assuntos
Inativação Metabólica , Tricotecenos , Animais , Glucuronídeos/metabolismo , Glucuronosiltransferase/metabolismo , Humanos , Hidrólise , Tricotecenos/química , Tricotecenos/metabolismo
4.
Mar Drugs ; 20(2)2022 Jan 18.
Artigo em Inglês | MEDLINE | ID: mdl-35200610

RESUMO

Eight trichothecenes, including four new compounds 1-4 and four known entities 5-8, together with one known cyclonerane (9) were isolated from the solid-state fermentation of Trichoderma brevicompactum NTU439 isolated from the marine alga Mastophora rosea. The structures of 1-9 were determined by 1D/2D NMR (nuclear magnetic resonance), MS (mass spectrometry), and IR (infrared spectroscopy) spectroscopic data. All of the compounds were evaluated for cytotoxic activity against HCT-116, PC-3, and SK-Hep-1 cancer cells by the SRB assay, and compound 8 showed promising cytotoxic activity against all three cancer cell lines with the IC50 values of 3.3 ± 0.3, 5.3 ± 0.3, and 1.8 ± 0.8 µM, respectively. Compounds 1-2, 4-6, and 7-8 potently inhibited LPS-induced NO production, and compounds 5 and 8 showed markedly inhibited gelatinolysis of MMP-9 in S1 protein-stimulated THP-1 monocytes.


Assuntos
Antineoplásicos/farmacologia , Hypocreales/metabolismo , Tricotecenos/farmacologia , Antineoplásicos/química , Antineoplásicos/isolamento & purificação , Carcinoma Hepatocelular/tratamento farmacológico , Linhagem Celular Tumoral , Neoplasias Colorretais/tratamento farmacológico , Células HCT116 , Humanos , Concentração Inibidora 50 , Neoplasias Hepáticas/tratamento farmacológico , Espectroscopia de Ressonância Magnética , Masculino , Espectrometria de Massas , Células PC-3 , Neoplasias da Próstata/tratamento farmacológico , Rodófitas/microbiologia , Tricotecenos/química , Tricotecenos/isolamento & purificação
5.
Molecules ; 27(1)2022 Jan 05.
Artigo em Inglês | MEDLINE | ID: mdl-35011560

RESUMO

Raw Ca-based montmorillonite (MMT) was treated by H2SO4, calcination and organic compounds (hexadecyltrimethyl ammonium bromide (HTAB), cetylpyridinium chloride (CPC) and chitosan (CTS)), respectively. The modified montmorillonites were characterized by different methods and their adsorption performances for three mycotoxins (Aflatoxin B1 (AFB1), zearalenone (ZEA) and deoxynivalenol (DON)) were evaluated at pH = 2.8 and 8.0, respectively. The results indicate that surfactants (CPC and HTAB) intercalation is the most efficient modification, which obviously improves the adsorption performance of montmorillonite for mycotoxins, with adsorption efficiency of above 90% for AFB1 and ZEA whether under acid or alkaline conditions, due to the increase in basal spacing and the improvement of hydrophobicity. Moreover, the adsorption efficiencies of AFB1 and ZEA over CPC-modified montmorillonite (CPC-AMMT-3) coexisting with vitamin B6 or lysine are still at a high level (all above 94%). All modified montmorillonites, however, have low adsorption efficiency for DON, with somewhat spherical molecular geometry.


Assuntos
Aflatoxina B1/química , Bentonita/química , Inativação Metabólica , Tricotecenos/química , Zearalenona/química , Ácidos/química , Adsorção , Cálcio/química , Micotoxinas/química , Temperatura
6.
Bioorg Med Chem Lett ; 42: 128091, 2021 06 15.
Artigo em Inglês | MEDLINE | ID: mdl-33964441

RESUMO

Activated macrophages contribute prominently to the progression and maintenance of almost all inflammatory and autoimmune diseases. Although non-specific elimination of these phagocytes has been shown to treat animal models of inflammatory disease, the same therapies have been compromised by unacceptable toxicities, because they also kill quiescent macrophages in healthy tissues. In the studies below, we exploit upregulation of folate receptor beta (FRß) on inflammatory (but not resting) macrophages to target a cytotoxic drug selectively to the inflammatory subset of macrophages. Because many of these activated macrophages are nondividing, we also employ verrucarin A as the cytotoxic payload, since it kills both mitotic and nonmitotic cells by blocking protein synthesis. By inserting a redox-sensitive self-immolative linker between the folate and verrucarin A, we further assure that release of unmodified verrucarin A is triggered primarily after internalization by an FRß-positive cell. The resulting folate-verrucarin A conjugate is shown to kill FR-expressing cells in vitro in a manner that can be inhibited by competition with 100-fold excess folic acid. The folate-verrucarin A conjugate is also shown to successfully treat a murine model of inflammatory peritonitis by eliminating inflammatory macrophages without killing other cells in the same peritonitis fluid. Based on this high specificity for inflammatory macrophages, we conclude that folate-verrucarin A warrants continued exploration as a potential therapy for inflammatory and autoimmune diseases in humans.


Assuntos
Modelos Animais de Doenças , Ácido Fólico/farmacologia , Macrófagos/efeitos dos fármacos , Peritonite/tratamento farmacológico , Tricotecenos/farmacologia , Animais , Relação Dose-Resposta a Droga , Receptor 2 de Folato/metabolismo , Ácido Fólico/química , Macrófagos/metabolismo , Camundongos , Estrutura Molecular , Peritonite/metabolismo , Relação Estrutura-Atividade , Tricotecenos/química
7.
Anal Bioanal Chem ; 413(19): 4801-4813, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34129076

RESUMO

Cytotoxic macrocyclic trichothecenes such as satratoxins are produced by chemotype S strains of Stachybotrys chartarum. Diseases such as stachybotryotoxicosis in animals and the sick building syndrome as a multifactorial disease complex in humans have been associated with this mold and its toxins. Less toxic non-chemotype S strains of S. chartarum are morphologically indistinguishable from chemotype S strains, which results in uncertainties in hazard characterization of isolates. To selectively identify macrocyclic trichothecene producing S. chartarum isolates, a set of sat14 gene-specific primers was designed and applied in a loop-mediated isothermal amplification (LAMP) assay using neutral red for visual signal detection. The assay was highly specific for S. chartarum strains of the macrocyclic trichothecene producing chemotype and showed no cross-reaction with non-macrocyclic trichothecene producing S. chartarum strains or 152 strains of 131 other fungal species. The assay's detection limit was 0.635 pg/rxn (picogram per reaction) with a reaction time of 60 min. Its high specificity and sensitivity as well as the cost-saving properties make the new assay an interesting and powerful diagnostic tool for easy and rapid testing.


Assuntos
Genótipo , Compostos Macrocíclicos/metabolismo , Técnicas de Diagnóstico Molecular/métodos , Técnicas de Amplificação de Ácido Nucleico/métodos , Stachybotrys/genética , Stachybotrys/metabolismo , Tricotecenos/metabolismo , Compostos Macrocíclicos/química , Sensibilidade e Especificidade , Tricotecenos/química
8.
Bioorg Chem ; 111: 104874, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-33887585

RESUMO

Seven previously undescribed trichothecenes, named trichothecrotocins M-S (1-7), along with five known compounds, were isolated from rice cultures of the potato-associated fungus Trichothecium crotocinigenum. Their structures and absolute configurations were determined through spectroscopic methods, single-crystal X-ray diffraction, and quantum chemistry calculations on ECD. Compound 1 possesses a rare 6,11-epoxy moiety in the trichothecene family. Compound 6 exhibited strong cytotoxic activity against MCF-7 cancer cell lines with an IC50 value of 2.34 ± 0.45 µM. It promoted apoptosis induction in MCF-7 cells. Moreover, cell cycle analysis showed cell cycle arrest caused by compound 6 at the G2/M phase which resulted to cell proliferation inhibition and pro-apoptotic activity. Further quantitative real-time PCR (qRT-PCR) analysis confirmed that the G2/M arrest was accompanied by upregulation of p21 and down regulation of cyclins B1 in 6-treated MCF-7 cells.


Assuntos
Antineoplásicos/farmacologia , Hypocreales/química , Solanum tuberosum/química , Tricotecenos/farmacologia , Antineoplásicos/química , Antineoplásicos/metabolismo , Apoptose/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Relação Dose-Resposta a Droga , Ensaios de Seleção de Medicamentos Antitumorais , Humanos , Hypocreales/metabolismo , Células MCF-7 , Simulação de Acoplamento Molecular , Estrutura Molecular , Solanum tuberosum/metabolismo , Relação Estrutura-Atividade , Tricotecenos/química , Tricotecenos/metabolismo
9.
Int J Mol Sci ; 22(21)2021 Oct 22.
Artigo em Inglês | MEDLINE | ID: mdl-34768859

RESUMO

Fusarium graminearum species complex produces type B trichothecenes oxygenated at C-7. In axenic liquid culture, F. graminearum mainly accumulates one of the three types of trichothecenes, namely 3-acetyldeoxyinvalenol, 15-acetyldeoxyinvalenol, or mixtures of 4,15-diacetylnivalenol/4-acetylnivalenol, depending on each strain's genetic background. The acetyl groups of these trichothecenes are slowly deacetylated to give deoxynivalenol (DON) or nivalenol (NIV) on solid medium culture. Due to the evolution of F. graminearum FgTri1, encoding a cytochrome P450 monooxygenase responsible for hydroxylation at both C-7 and C-8, new derivatives of DON, designated as NX-type trichothecenes, have recently emerged. To assess the risks of emergence of new NX-type trichothecenes, we examined the effects of replacing FgTri1 in the three chemotypes with FgTri1_NX chemotype, which encodes a cytochrome P450 monooxygenase that can only hydroxylate C-7 of trichothecenes. Similar to the transgenic DON chemotypes, the transgenic NIV chemotype strain accumulated NX-type 4-deoxytrichothecenes in axenic liquid culture. C-4 oxygenated trichothecenes were marginal, despite the presence of a functional FgTri13 encoding a C-4 hydroxylase. At present, outcrossing of the currently occurring NX chemotype with NIV chemotype strains of F. graminearum in the natural environment likely will not yield a new strain that produces a C-4 oxygenated NX-type trichothecene.


Assuntos
Sistema Enzimático do Citocromo P-450/metabolismo , Fusarium/metabolismo , Tricotecenos/metabolismo , Cultura Axênica , Sistema Enzimático do Citocromo P-450/genética , Proteínas Fúngicas/metabolismo , Fusarium/genética , Organismos Geneticamente Modificados/genética , Tricotecenos/química
10.
Int J Mol Sci ; 22(4)2021 Feb 05.
Artigo em Inglês | MEDLINE | ID: mdl-33562610

RESUMO

Trichothecenes are the most prevalent mycotoxins contaminating cereal grains. Some of them are also considered as the virulence factors of Fusarium head blight disease. However, the mechanism behind the structure-activity relationship for trichothecenes remains unexplained. Filling this information gap is a crucial step for developing strategies to manage this large family of mycotoxins in food and feed. Here, we perform an in-depth re-examination of the existing structures of Saccharomyces cerevisiae ribosome complexed with three different trichothecenes. Multiple binding interactions between trichothecenes and 25S rRNA, including hydrogen bonds, nonpolar pi stacking interactions and metal ion coordination interactions, are identified as important binding determinants. These interactions are mainly contributed by the key structural elements to the toxicity of trichothecenes, including the oxygen in the 12,13-epoxide ring and a double bond between C9 and C10. In addition, the C3-OH group also participates in binding. The comparison of three trichothecenes binding to the ribosome, along with their binding pocket architecture, suggests that the substitutions at different positions impact trichothecenes binding in two different patterns. Moreover, the binding of trichothecenes induced conformation changes of several nucleotide bases in 25S rRNA. This then provides a structural framework for understanding the structure-activity relationships apparent in trichothecenes. This study will facilitate the development of strategies aimed at detoxifying mycotoxins in food and feed and at improving the resistance of cereal crops to Fusarium fungal diseases.


Assuntos
Micotoxinas/química , Tricotecenos/química , Sítios de Ligação , Grão Comestível/toxicidade , Contaminação de Alimentos , Fusarium/química , Fusarium/patogenicidade , Inativação Metabólica , Modelos Moleculares , Estrutura Molecular , Micotoxinas/metabolismo , Micotoxinas/toxicidade , Conformação de Ácido Nucleico/efeitos dos fármacos , RNA Fúngico/química , RNA Fúngico/efeitos dos fármacos , RNA Ribossômico/química , RNA Ribossômico/efeitos dos fármacos , Ribossomos/efeitos dos fármacos , Ribossomos/metabolismo , Saccharomyces cerevisiae/efeitos dos fármacos , Saccharomyces cerevisiae/metabolismo , Relação Estrutura-Atividade , Tricotecenos/metabolismo , Tricotecenos/toxicidade
11.
Molecules ; 26(8)2021 Apr 13.
Artigo em Inglês | MEDLINE | ID: mdl-33924544

RESUMO

Deoxynivalenol (DON) is one of the most common mycotoxins in grains, causing gastrointestinal inflammation, neurotoxicity, hepatotoxicity and embryotoxicity, even at a low quantity. In this study, a facile electrochemical aptasensor was established for the rapid and sensitive determination of DON based on a multifunctional N-doped Cu-metallic organic framework (N-Cu-MOF) nanomaterial. The N-Cu-MOF, with a large specific surface area and good electrical conductivity, served not only as an optimal electrical signal probe but also as an effective supporting substrate for stabilizing aptamers through the interactions of amino (-NH2) and copper. Under the optimal conditions, the proposed sensor provided a wide linear concentration range of 0.02-20 ng mL-1 (R2 = 0.994), showing high sensitivity, with a lower detection limit of 0.008 ng mL-1, and good selectivity. The sensor's effectiveness was also verified in real spiked wheat samples with satisfactory recoveries of 95.6-105.9%. The current work provides a flexible approach for the rapid and sensitive analysis of highly toxic DON in food samples and may also be easily extended to detect other hazardous substances with alternative target-recognition aptamers.


Assuntos
Técnicas Biossensoriais/métodos , Cobre/química , Técnicas Eletroquímicas/métodos , Estruturas Metalorgânicas/química , Nanoestruturas/química , Tricotecenos/química , Triticum/química
12.
J Comput Chem ; 41(14): 1330-1336, 2020 05 30.
Artigo em Inglês | MEDLINE | ID: mdl-32067246

RESUMO

Tri11 (now renamed as tri22) encoded cytochrome P450 monooxygenase in Trichoderma brevicompactum catalyzes the C-4 C-H hydroxylation of 12, 13-epoxytrichothec-9-ene (EPT) to produce trichodermol in the biosynthetic pathway of trichodermin/harzianum A. The density functional theory (DFT)-quantum mechanics (QM) approach is applied to elucidate the hydroxylation of EPT by using a model active species of P450 (Cpd I). The QM calculations were performed on the active site complex, to find out transition-state structure, intermediate, and product complexes for the two spin states at different potential energy surfaces. The two state reactivity rebound-free product formation resulted from the interplay of two spin states (doublet and quartet).


Assuntos
Sistema Enzimático do Citocromo P-450/metabolismo , Hypocreales/enzimologia , Tricodermina/metabolismo , Tricotecenos/metabolismo , Biocatálise , Sistema Enzimático do Citocromo P-450/química , Teoria da Densidade Funcional , Hidroxilação , Tricodermina/química , Tricotecenos/química
13.
PLoS Pathog ; 14(4): e1006946, 2018 04.
Artigo em Inglês | MEDLINE | ID: mdl-29649280

RESUMO

Trichothecenes are a family of terpenoid toxins produced by multiple genera of fungi, including plant and insect pathogens. Some trichothecenes produced by the fungus Fusarium are among the mycotoxins of greatest concern to food and feed safety because of their toxicity and frequent occurrence in cereal crops, and trichothecene production contributes to pathogenesis of some Fusarium species on plants. Collectively, fungi produce over 150 trichothecene analogs: i.e., molecules that share the same core structure but differ in patterns of substituents attached to the core structure. Here, we carried out genomic, phylogenetic, gene-function, and analytical chemistry studies of strains from nine fungal genera to identify genetic variation responsible for trichothecene structural diversity and to gain insight into evolutionary processes that have contributed to the variation. The results indicate that structural diversity has resulted from gain, loss, and functional changes of trichothecene biosynthetic (TRI) genes. The results also indicate that the presence of some substituents has arisen independently in different fungi by gain of different genes with the same function. Variation in TRI gene duplication and number of TRI loci was also observed among the fungi examined, but there was no evidence that such genetic differences have contributed to trichothecene structural variation. We also inferred ancestral states of the TRI cluster and trichothecene biosynthetic pathway, and proposed scenarios for changes in trichothecene structures during divergence of TRI cluster homologs. Together, our findings provide insight into evolutionary processes responsible for structural diversification of toxins produced by pathogenic fungi.


Assuntos
Proteínas Fúngicas/genética , Regulação Fúngica da Expressão Gênica , Micotoxinas/química , Filogenia , Trichoderma/genética , Tricotecenos/química , DNA Fúngico , Genômica , Micotoxinas/farmacologia , Trichoderma/efeitos dos fármacos , Trichoderma/crescimento & desenvolvimento , Tricotecenos/farmacologia
14.
Chem Res Toxicol ; 33(2): 515-521, 2020 02 17.
Artigo em Inglês | MEDLINE | ID: mdl-31867960

RESUMO

Deoxynivalenol (DON) is a trichothecene mycotoxin that is produced by several species of Fusarium, which may infect grain crops. DON, as well as other type-B trichothecenes, contain an α,ß-unsaturated carbonyl group that may react with sulfhydryl groups in, for example, amino acids and peptides. Such conjugates have been shown to occur in plants. Nucleophilic addition of thiols to the conjugated double bond in DON afforded several isomeric reaction products, and the thermodynamically favored isomers of DON-10-cysteine and DON-10-glutathione have been prepared and characterized previously. This study reports the preparation and characterization of the kinetically favored DON-10-cysteine isomer. We subsequently studied and compared the rate of the deconjugation reaction of the two DON-10-cysteine isomers and the thermodynamically favored DON-10-glutathione adduct. The deconjugation rate of the thermodynamically favored thiol conjugates was slow with half-lives of weeks even at pH 10.7, while the kinetically favored DON-10-cysteine isomer deconjugated within a few hours, affording free DON. We adapted a simple and rapid oxidation protocol in which the sulfide linkage was oxidized to a sulfoxide or sulfone that, when treated with the base, rapidly eliminated the adducted thiol as its sulfenate or sulfinate to afford free DON. The deconjugation reactions of the sulfoxides and sulfones of thermodynamically favored DON-10-thiols were complete within hours or minutes at pH 10.7, respectively. The increase in deconjugation rates for the kinetically favored DON-10-cysteine were less dramatic. Oxidation of sulfides to sulfoxides is known to occur in vivo, and thus, our data show that thiol-conjugated DON might become bioavailable via sulfide oxidation followed by elimination to regenerate DON. The oxidation-elimination approach could also be useful for the indirect quantification of DON-10-thiol conjugates in plant and animal tissues.


Assuntos
Micotoxinas/química , Compostos de Sulfidrila/química , Tricotecenos/química , Concentração de Íons de Hidrogênio , Modelos Moleculares , Estrutura Molecular , Oxirredução
15.
Bioorg Med Chem Lett ; 30(17): 127375, 2020 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-32739000

RESUMO

Two new trichothecene sesquiterpenes, trichobreols D (1) and E (2), were isolated from the culture broth of marine-derived Trichoderma cf. brevicompactum together with trichobreol A (3). The structures of 1 and 2 were assigned on the basis of their spectroscopic data. Compound 1 inhibited the growth of two yeast-like fungi, Candida albicans and Cryptococcus neoformans, with equivalent MIC values (6.3 µg/mL), while 2 gave MIC values of 12.5 and 25 µg/mL, respectively. The antifungal activities of five semisynthetic derivatives (4-8) prepared from 3 were evaluated and compared to investigate the preliminary structure-activity relationship.


Assuntos
Antifúngicos/química , Sesquiterpenos/química , Trichoderma/química , Tricotecenos/química , Antifúngicos/isolamento & purificação , Antifúngicos/farmacologia , Candida albicans/efeitos dos fármacos , Cryptococcus neoformans/efeitos dos fármacos , Espectroscopia de Ressonância Magnética , Testes de Sensibilidade Microbiana , Conformação Molecular , Rodófitas/microbiologia , Sesquiterpenos/isolamento & purificação , Sesquiterpenos/farmacologia , Relação Estrutura-Atividade , Trichoderma/metabolismo , Tricotecenos/isolamento & purificação , Tricotecenos/farmacologia
16.
Appl Microbiol Biotechnol ; 104(12): 5185-5199, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32328680

RESUMO

Trichothecenes are sesquiterpene toxins produced by diverse but relatively few fungal species in at least three classes of Ascomycetes: Dothideomycetes, Eurotiomycetes, and Sordariomycetes. Approximately 200 structurally distinct trichothecene analogs have been described, but a given fungal species typically produces only a small subset of analogs. All trichothecenes share a core structure consisting of a four-ring nucleus known as 12,13-epoxytrichothec-9-ene. This structure can be substituted at various positions with hydroxyl, acyl, or keto groups to give rise to the diversity of trichothecene structures that has been described. Over the last 30 years, the genetic and biochemical pathways required for trichothecene biosynthesis in several species of the fungi Fusarium and Trichoderma have been elucidated. In addition, phylogenetic and functional analyses of trichothecene biosynthetic (TRI) genes from fungi in multiple genera have provided insights into how acquisition, loss, and changes in functions of TRI genes have given rise to the diversity of trichothecene structures. These analyses also suggest both divergence and convergence of TRI gene function during the evolutionary history of trichothecene biosynthesis. What has driven trichothecene structural diversification remains an unanswered question. However, insight into the role of trichothecenes in plant pathogenesis of Fusarium species and into plant glucosyltransferases that detoxify the toxins by glycosylating them point to a possible driver. Because the glucosyltransferases can have substrate specificity, changes in trichothecene structures produced by a fungus could allow it to evade detoxification by the plant enzymes. Thus, it is possible that advantages conferred by evading detoxification have contributed to trichothecene structural diversification. KEY POINTS : • TRI genes have evolved by diverse processes: loss, acquisition and changes in function. • Some TRI genes have acquired the same function by convergent evolution. • Some other TRI genes have evolved divergently to have different functions. • Some TRI genes were acquired or resulted from diversification in function of other genes. • Substrate specificity of plant glucosyltransferases could drive trichothecene diversity.


Assuntos
Fungos/metabolismo , Variação Genética , Micotoxinas/química , Micotoxinas/genética , Tricotecenos/química , DNA Fúngico/genética , Fungos/classificação , Fungos/genética , Regulação Fúngica da Expressão Gênica , Filogenia
17.
Appl Microbiol Biotechnol ; 104(13): 6045-6056, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32440704

RESUMO

Deoxynivalenol (DON) is commonly found in wheat and wheat-derived foods, posing a threat to human health. Biodegradation is an efficient and eco-friendly measure for mycotoxin detoxification. Understanding the mechanism of DON biodegradation is hence of great importance. Herein, we report the application of metabolomics methods for the analysis of DON degradation by a bacterial consortium isolated from wheat leaves collected in Jiangsu Province. Metabolomics analysis combined with a nuclear magnetic resonance analysis revealed the main degradation product, 3-keto-DON, and a minor degradation product, 3-epi-DON. Further study illustrated that DON underwent a two-step epimerization through the intermediate 3-keto-DON. Sequencing analysis of the 16S rRNA metagenome of the microorganismal community suggested that the abundance of three bacterial genera, Achromobacter, Sphingopyxis, and Sphingomonas, substantially increased during the coculture of bacterial consortium and DON. Further investigation revealed that Devosia sp. might be responsible for the epimerization of 3-keto-DON. These findings shed light on the catabolic pathways of DON during biodegradation and illustrate the potential of using metabolomics approaches in biodegradation studies.Key Points• A bacterial consortium was isolated with good deoxynivalenol-degrading potential. • Metabolomics approaches were successfully used to interpret the degradation pathway. • A trace-amount degradation product was determined by metabolomics and NMR analysis. Graphical Abstract .


Assuntos
Bactérias/metabolismo , Consórcios Microbianos/fisiologia , Tricotecenos/metabolismo , Bactérias/classificação , Bactérias/genética , Bactérias/isolamento & purificação , Biodegradação Ambiental , Inativação Metabólica , Metabolômica , Metagenômica , Consórcios Microbianos/genética , Filogenia , RNA Ribossômico 16S/genética , Tricotecenos/química , Triticum/microbiologia
18.
Appl Microbiol Biotechnol ; 104(6): 2731-2743, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-32002603

RESUMO

There are a large number of valuable substances in diatoms, such as neutral lipid and pigments. However, due to the lack of clear metabolic pathways, their applications are still limited. Recently, chemical modulators are found to be powerful tools to investigate the metabolic pathways of neutral lipids. Thus, in this study, to identify new neutral lipid accumulation effectors, we screened the natural products that we separated before in the model diatom Phaeodactylum tricornutum (P. tricornutum) by using Nile-red staining method. Two compounds, penicillide and verrucarin J which were isolated from two marine fungal strains, were identified to promote neutral lipid accumulation. However, penicillide and verrucarin J were also found to significantly inhibit the growth of P. tricornutum through specifically inhibiting the photosynthesis of P. tricornutum. Quantitative analysis results showed that penicillide and verrucarin J significantly increased total lipid and triacylglycerol (TAG) contents, which are consistent with previous Nile-red staining results. The expression of key genes such as DGAT2D, GPAT2, LPAT2, and PAP involved in TAG synthesis and unsaturated fatty acids also increased after penicillide and verrucarin J treatments. Besides, many TAG-rich plastoglobuli formed in plastids shown by increased lipid droplets in the cytosol. Finally, penicillide and verrucarin J were found to reduce the expression of synthetic genes of fucoxanthin, and consequently reduced the content of fucoxanthin, indicating that there might be crosstalk between lipid metabolism and fucoxanthin metabolism. Thus, our work exhibits two useful compounds that could be used to further study the metabolic pathways of neutral lipid and fucoxanthin, which will fulfill the promise of diatoms as low cost, high value, sustainable feedstock for high-value products such as neutral lipid and pigments.


Assuntos
Produtos Biológicos/farmacologia , Diatomáceas/efeitos dos fármacos , Fungos/química , Metabolismo dos Lipídeos/efeitos dos fármacos , Redes e Vias Metabólicas/efeitos dos fármacos , Organismos Aquáticos/química , Produtos Biológicos/química , Lipídeos/biossíntese , Coloração e Rotulagem , Tricotecenos/química , Tricotecenos/farmacologia
19.
Magn Reson Chem ; 58(2): 198-203, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-31692051

RESUMO

The exquisitely cytotoxic macrolides, satratoxins G and H, have been reisolated from a solvent extract of a rice culture inoculated with Stachybotrys chartarum to be used as high-purity reference compounds for analytical analyses. Extensive chromatographic separation realized the compounds that were fully recharacterized in two solvents by 1D- and 2D-NMR spectroscopy, revealing some discrepancies in the nuclear magnetic resonance (NMR) data as compared with the previously reported values found in the literature. Detailed spectra are provided in order to aid future identification and dereplication.


Assuntos
Espectroscopia de Ressonância Magnética Nuclear de Carbono-13/métodos , Espectroscopia de Prótons por Ressonância Magnética/métodos , Tricotecenos/química , Oryza/microbiologia , Stachybotrys/metabolismo
20.
Compr Rev Food Sci Food Saf ; 19(2): 895-926, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-33325179

RESUMO

Deoxynivalenol (DON) has drawn global attention because of its prevalence and significant effects on human or animal health. Biological remedies for DON have been developed from preharvest to postharvest. Applying microbes, including bacteria, fungi (yeast and molds), and enzymes, results in inhibited synthesis, structural destruction, or adsorption of DON. DON can be degraded into masked forms by phase I metabolism or phase II metabolism. During food processing, DON content changes dynamically and is even transformed. Physical, chemical, thermal, or biological processes physically reduce DON content. Temperature, heating time, enzymes, food additives, microorganisms, food composition, contamination level, and other ingredients are key factors. Although DON content can be reduced during food processing, increases in other toxins, such as DON-3-ß-d-glucoside and 3-acetyl-DON, can be potentially risky. The application of biodegradation methods in food processing bears research significance. Both microorganisms and enzymes can be potentially used. Novel techniques, such as RNA interference, omics technologies, or enzymes coupled with the genetic engineering method, can be introduced. This review systematically updates the understanding of masked forms of DON, biological degradation strategy, fate of DON during processing, and future trends for biodegradation. Challenges to the successful application of biological methods may include the stability and suitability of the detoxification agents, security of degradation products, and successful application for industrial production.


Assuntos
Contaminação de Alimentos/prevenção & controle , Manipulação de Alimentos/métodos , Tricotecenos/química , Animais , Bactérias , Biotransformação , Fungos , Tricotecenos/metabolismo
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