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1.
Chem Pharm Bull (Tokyo) ; 72(7): 693-699, 2024.
Article in English | MEDLINE | ID: mdl-39048375

ABSTRACT

This study evaluated the ability of isolated or semisynthesized trichothecene sesquiterpenes to prevent cancer emergence and proliferation and inhibit signal transducer and activator of transcription-3 (STAT3) phosphorylation through in vitro assays. Trichothecinol A (TTC-A), which bears a hydroxy group at C3, exhibited greater cancer prevention, antiproliferation, and STAT3 phosphorylation inhibition effects than trichothecin (TTC), which lacks a hydroxy group at C3. Furthermore, trichothecinol B (TTC-B), which is a reduced derivative of TTC and has similar cytotoxic effect, showed substantially weaker chemoprotection and STAT3 phosphorylation inhibition effects than TTC. These results clearly indicate that the hydroxy group at C3 and carbonyl group at C8 are crucial for inducing both potent chemoprevention and STAT3 phosphorylation inhibition.


Subject(s)
Cell Proliferation , STAT3 Transcription Factor , Trichothecenes , STAT3 Transcription Factor/antagonists & inhibitors , STAT3 Transcription Factor/metabolism , Trichothecenes/chemistry , Trichothecenes/pharmacology , Trichothecenes/antagonists & inhibitors , Humans , Cell Proliferation/drug effects , Structure-Activity Relationship , Phosphorylation/drug effects , Cell Line, Tumor , Molecular Structure , Drug Screening Assays, Antitumor , Dose-Response Relationship, Drug , Antineoplastic Agents/pharmacology , Antineoplastic Agents/chemistry
2.
Int J Mol Sci ; 25(12)2024 Jun 11.
Article in English | MEDLINE | ID: mdl-38928120

ABSTRACT

The compound 15-deacetylcalonectrin (15-deCAL) is a common pathway intermediate in the biosynthesis of Fusarium trichothecenes. This tricyclic intermediate is metabolized to calonectrin (CAL) by trichothecene 15-O-acetyltransferase encoded by Tri3. Unlike other trichothecene pathway Tri gene mutants, the Δtri3 mutant produces lower amounts of the knocked-out enzyme's substrate 15-deCAL, and instead, accumulates higher quantities of earlier bicyclic intermediate and shunt metabolites. Furthermore, evolutionary studies suggest that Tri3 may play a role in shaping the chemotypes of trichothecene-producing Fusarium strains. To better understand the functional role of Tri3p in biosynthesis and evolution, we aimed to develop a method to produce 15-deCAL by using transgenic Fusarium graminearum strains derived from a trichothecene overproducer. Unfortunately, introducing mutant Tri3, encoding a catalytically impaired but structurally intact acetylase, did not improve the low 15-deCAL production level of the ΔFgtri3 deletion strain, and the bicyclic products continued to accumulate as the major metabolites of the active-site mutant. These findings are discussed in light of the enzyme responsible for 15-deCAL production in trichothecene biosynthesis machinery. To efficiently produce 15-deCAL, we tested an alternative strategy of using a CAL-overproducing transformant. By feeding a crude CAL extract to a Fusarium commune strain that was isolated in this study and capable of specifically deacetylating C-15 acetyl, 15-deCAL was efficiently recovered. The substrate produced in this manner can be used for kinetic investigations of this enzyme and its possible role in chemotype diversification.


Subject(s)
Fusarium , Mutation , Trichothecenes , Fusarium/genetics , Fusarium/metabolism , Trichothecenes/metabolism , Acetyltransferases/metabolism , Acetyltransferases/genetics , Fungal Proteins/genetics , Fungal Proteins/metabolism , Biosynthetic Pathways/genetics
3.
Toxics ; 12(5)2024 May 06.
Article in English | MEDLINE | ID: mdl-38787115

ABSTRACT

With increasing health awareness and the accelerating pace of life, whole-grain prepared foods have gained popularity due to their health benefits and convenience. However, the potential risk of type B trichothecene toxins has also increased, and these mycotoxins in such foods are rarely regulated. In this study, a quantitative method combining a single-valve dual-column automatic online solid-phase extraction system with ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) was developed for the first time using restricted-access media columns. This method can simultaneously determine trace residues of seven type B trichothecenes within 15 min. The method is convenient, sensitive (limit of detection and quantification of 0.05-0.6 µg/kg and 0.15-2 µg/kg, respectively), accurate (recovery rates of 90.3%-106.6%, relative standard deviation < 4.3%), and robust (>1000 times). The established method was applied to 160 prepared food samples of eight categories sold in China. At least one toxin was detected in 70% of the samples. Whole-wheat dumpling wrappers had the highest contamination rate (95%) and the highest total content of type B trichothecenes in a single sample (2077.3 µg/kg). Exposure risk assessment indicated that the contamination of whole-grain prepared foods has been underestimated. The total health risk index of whole-wheat dumpling wrappers, which are susceptible to deoxynivalenol, reached 136.41%, posing a significant threat to human health. Effective measures urgently need to be taken to control this risk.

4.
J Fungi (Basel) ; 10(4)2024 Mar 22.
Article in English | MEDLINE | ID: mdl-38667911

ABSTRACT

In China, Fusarium pseudograminearum has emerged as a major pathogen causing Fusarium crown rot (FCR) and caused significant losses. Studies on the pathogen's properties, especially its mating type and trichothecene chemotypes, are critical with respect to disease epidemiology and food/feed safety. There are currently few available reports on these issues. This study investigated the species composition, mating type idiomorphs, and trichothecene genotypes of Fusarium spp. causing FCR in Henan, China. A significant shift in F. pseudograminearum-induced FCR was found in the present study. Of the 144 purified strains, 143 were F. pseudograminearum, whereas only 1 Fusarium graminearum was identified. Moreover, a significant trichothecene-producing capability of F. pseudograminearum strains from Henan was observed in this work. Among the 143 F. pseudograminearum strains identified, F. pseudograminearum with a 15ADON genotype was found to be predominant (133 isolates), accounting for 92.36% of all strains, followed by F. pseudograminearum with a 3ADON genotype, whereas only one NIV genotype strain was detected. Overall, a relatively well-balanced 1:1 ratio of the F. pseudograminearum population was found in Henan. To the best of our knowledge, this is the first study that has examined the Fusarium populations responsible for FCR across the Henan wheat-growing region.

5.
Front Plant Sci ; 15: 1389605, 2024.
Article in English | MEDLINE | ID: mdl-38650698

ABSTRACT

Fusarium graminearum, the causal agent of Fusarium head blight (FHB), produces various mycotoxins that contaminate wheat grains and cause profound health problems in humans and animals. Deoxynivalenol (DON) is the most common trichothecene found in contaminated grains. Our previous study showed that Arabidopsis-expressing F. graminearum trichothecene 3-O-acetyltransferase (FgTRI101) converted DON to 3-acetyldeoxynivalenol (3-ADON) and excreted it outside of Arabidopsis cells. To determine if wheat can convert and excrete 3-ADON and reduce FHB and DON contamination, FgTRI101 was cloned and introduced into wheat cv Bobwhite. Four independent transgenic lines containing FgTRI101 were identified. Gene expression studies showed that FgTRI101 was highly expressed in wheat leaf and spike tissues in the transgenic line FgTri101-1606. The seedlings of two FgTri101 transgenic wheat lines (FgTri101-1606 and 1651) grew significantly longer roots than the controls on media containing 5 µg/mL DON; however, the 3-ADON conversion and excretion was detected inconsistently in the seedlings of FgTri101-1606. Further analyses did not detect 3-ADON or other possible DON-related products in FgTri101-1606 seedlings after adding deuterium-labeled DON into the growth media. FgTri101-transgenic wheat plants showed significantly enhanced FHB resistance and lower DON content after they were infected with F. graminearum, but 3-ADON was not detected. Our study suggests that it is promising to utilize FgTRI101, a gene that the fungus uses for self-protection, for managing FHB and mycotoxin in wheat production.

6.
Int J Mol Sci ; 25(8)2024 Apr 12.
Article in English | MEDLINE | ID: mdl-38673874

ABSTRACT

The trichothecene biosynthesis in Fusarium begins with the cyclization of farnesyl pyrophosphate to trichodiene, followed by subsequent oxygenation to isotrichotriol. This initial bicyclic intermediate is further cyclized to isotrichodermol (ITDmol), a tricyclic precursor with a toxic trichothecene skeleton. Although the first cyclization and subsequent oxygenation are catalyzed by enzymes encoded by Tri5 and Tri4, the second cyclization occurs non-enzymatically. Following ITDmol formation, the enzymes encoded by Tri101, Tri11, Tri3, and Tri1 catalyze 3-O-acetylation, 15-hydroxylation, 15-O-acetylation, and A-ring oxygenation, respectively. In this study, we extensively analyzed the metabolites of the corresponding pathway-blocked mutants of Fusarium graminearum. The disruption of these Tri genes, except Tri3, led to the accumulation of tricyclic trichothecenes as the main products: ITDmol due to Tri101 disruption; a mixture of isotrichodermin (ITD), 7-hydroxyisotrichodermin (7-HIT), and 8-hydroxyisotrichodermin (8-HIT) due to Tri11 disruption; and a mixture of calonectrin and 3-deacetylcalonectrin due to Tri1 disruption. However, the ΔFgtri3 mutant accumulated substantial amounts of bicyclic metabolites, isotrichotriol and trichotriol, in addition to tricyclic 15-deacetylcalonectrin (15-deCAL). The ΔFgtri5ΔFgtri3 double gene disruptant transformed ITD into 7-HIT, 8-HIT, and 15-deCAL. The deletion of FgTri3 and overexpression of Tri6 and Tri10 trichothecene regulatory genes did not result in the accumulation of 15-deCAL in the transgenic strain. Thus, the absence of Tri3p and/or the presence of a small amount of 15-deCAL adversely affected the non-enzymatic second cyclization and C-15 hydroxylation steps.


Subject(s)
Fusarium , Trichothecenes , Fusarium/metabolism , Fusarium/genetics , Cyclization , Trichothecenes/metabolism , Acetylation , Fungal Proteins/metabolism , Fungal Proteins/genetics , Polyisoprenyl Phosphates/metabolism , Biosynthetic Pathways
7.
Toxicon ; 243: 107718, 2024 May 28.
Article in English | MEDLINE | ID: mdl-38614246

ABSTRACT

Mycotoxins are toxic, fungal secondary metabolites that contaminate agricultural commodities, food, and feed. Among them, T-2, HT-2, and diacetoxyscirpenol (DAS; the major type A trichothecene) are primarily produced from Fusarium species. These mycotoxins exert numerous toxicological effects in animals and humans, such as dermatotoxicity, haematotoxicity, hepatotoxicity, nephrotoxicity, neurotoxicity, and immunotoxicity. In the present study, human Jurkat T cells were used as a model to investigate apoptotic cell death induced by T-2, HT-2, and DAS. The results showed that T-2, HT-2, and DAS decreased cell viability and increased production of Reactive Oxygen Species in a time- and dose-dependency. Based on their IC50 values, they could be ranked in decreasing order of cytotoxicity as T-2 > HT-2 > DAS. All tested mycotoxins caused DNA fragmentation, up-regulated cytochrome C, caspase 3, and caspase 9 mRNA levels, and down-regulated the relative expression of Bcl-2 and caspase 8. The effects of these trichothecenes on apoptosis were determined based on flow cytometry. At the IC50 concentrations, the percentages of apoptotic cells were significantly higher than for the controls. Taken together, these data suggested that T-2, HT-2, and DAS could induce apoptosis through the mitochondrial apoptotic pathway.


Subject(s)
Apoptosis , Cell Survival , Reactive Oxygen Species , T-2 Toxin , Trichothecenes , Humans , Trichothecenes/toxicity , Jurkat Cells , T-2 Toxin/toxicity , T-2 Toxin/analogs & derivatives , Apoptosis/drug effects , Reactive Oxygen Species/metabolism , Cell Survival/drug effects , DNA Fragmentation/drug effects , Cytochromes c/metabolism , Caspase 3/metabolism , Caspase 9/metabolism , Proto-Oncogene Proteins c-bcl-2/metabolism
8.
Nat Prod Res ; : 1-7, 2024 Mar 27.
Article in English | MEDLINE | ID: mdl-38534130

ABSTRACT

Five trichothecenes including a new one, together with two previously undescribed benzene derivatives were isolated from the solid culture of Trichothecium sp. Their structures were established by 1D and 2D NMR data in conjunction with HR-ESI-MS analysis. Compounds 1-5 exhibited cytotoxicity against MCF-7 cell lines at various levels ranging from IC50 of 7.23 to 16.95 µM. Compound 6 decreased the concentration of blood lipids in zebra fish at the concentration of 20 µM.

9.
Toxins (Basel) ; 16(2)2024 02 06.
Article in English | MEDLINE | ID: mdl-38393168

ABSTRACT

Fusarium fungi produce a diverse array of mycotoxic metabolites during the pathogenesis of cereals. Some, such as the trichothecenes and fumonisins, are phytotoxic, acting as non-proteinaceous effectors that facilitate disease development in cereals. Over the last few decades, we have gained some depth of understanding as to how trichothecenes and fumonisins interact with plant cells and how plants deploy mycotoxin detoxification and resistance strategies to defend themselves against the producer fungi. The cereal-mycotoxin interaction is part of a co-evolutionary dance between Fusarium and cereals, as evidenced by a trichothecene-responsive, taxonomically restricted, cereal gene competing with a fungal effector protein and enhancing tolerance to the trichothecene and resistance to DON-producing F. graminearum. But the binary fungal-plant interaction is part of a bigger ecosystem wherein other microbes and insects have been shown to interact with fungal mycotoxins, directly or indirectly through host plants. We are only beginning to unravel the extent to which trichothecenes, fumonisins and other mycotoxins play a role in fungal-ecosystem interactions. We now have tools to determine how, when and where mycotoxins impact and are impacted by the microbiome and microfauna. As more mycotoxins are described, research into their individual and synergistic toxicity and their interactions with the crop ecosystem will give insights into how we can holistically breed for and cultivate healthy crops.


Subject(s)
Fumonisins , Fusarium , Mycotoxins , Trichothecenes , Fumonisins/metabolism , Edible Grain/microbiology , Fusarium/genetics , Fusarium/metabolism , Ecosystem , Plant Breeding , Trichothecenes/toxicity , Trichothecenes/metabolism , Mycotoxins/toxicity , Fungal Proteins/genetics , Plant Diseases/microbiology
10.
Poult Sci ; 103(3): 103471, 2024 Mar.
Article in English | MEDLINE | ID: mdl-38295499

ABSTRACT

Contamination of feed with mycotoxins has become a severe issue worldwide. Among the most prevalent trichothecene mycotoxins, T-2 toxin is of particular importance for livestock production, including poultry posing a significant threat to animal health and productivity. This review article aims to comprehensively analyze the pathological consequences, metabolism, and toxic effects of T-2 toxin in poultry. Trichothecene mycotoxins, primarily produced by Fusarium species, are notorious for their potent toxicity. T-2 toxin exhibits a broad spectrum of negative effects on poultry species, leading to substantial economic losses as well as concerns about animal welfare and food safety in modern agriculture. T-2 toxin exposure easily results in negative pathological consequences in the gastrointestinal tract, as well as in parenchymal tissues like the liver (as the key organ for its metabolism), kidneys, or reproductive organs. In addition, it also intensely damages immune system-related tissues such as the spleen, the bursa of Fabricius, or the thymus causing immunosuppression and increasing the susceptibility of the animals to infectious diseases, as well as making immunization programs less effective. The toxin also damages cellular processes on the transcriptional and translational levels and induces apoptosis through the activation of numerous cellular signaling cascades. Furthermore, according to recent studies, besides the direct effects on the abovementioned processes, T-2 toxin induces the production of reactive molecules and free radicals resulting in oxidative distress and concomitantly occurring cellular damage. In conclusion, this review article provides a complex and detailed overview of the metabolism, pathological consequences, mechanism of action as well as the immunomodulatory and oxidative stress-related effects of T-2 toxin. Understanding these effects in poultry is crucial for developing strategies to mitigate the impact of the T-2 toxin on avian health and food safety in the future.


Subject(s)
Mycotoxins , T-2 Toxin , Trichothecenes , Animals , T-2 Toxin/toxicity , T-2 Toxin/analysis , T-2 Toxin/metabolism , Poultry/metabolism , Food Contamination/prevention & control , Chickens/metabolism , Trichothecenes/toxicity , Mycotoxins/metabolism
11.
Appl Microbiol Biotechnol ; 108(1): 152, 2024 Dec.
Article in English | MEDLINE | ID: mdl-38183477

ABSTRACT

Trichothecenes are a structurally diverse family of toxic secondary metabolites produced by certain species of multiple fungal genera. All trichothecene analogs share a core 12,13-epoxytrichothec-9-ene (EPT) structure but differ in presence, absence and types of substituents attached to various positions of EPT. Formation of some of the structural diversity begins early in the biosynthetic pathway such that some producing species have few trichothecene biosynthetic intermediates in common. Cytochrome P450 monooxygenases (P450s) play critical roles in formation of trichothecene structural diversity. Within some species, relaxed substrate specificities of P450s allow individual orthologs of the enzymes to modify multiple trichothecene biosynthetic intermediates. It is not clear, however, whether the relaxed specificity extends to biosynthetic intermediates that are not produced by the species in which the orthologs originate. To address this knowledge gap, we used a mutant complementation-heterologous expression analysis to assess whether orthologs of three trichothecene biosynthetic P450s (TRI11, TRI13 and TRI22) from Fusarium sporotrichioides, Trichoderma arundinaceum, and Paramyrothecium roridum can modify trichothecene biosynthetic intermediates that they do not encounter in the organism in which they originated. The results indicate that TRI13 and TRI22 could not modify the intermediates that they do not normally encounter, whereas TRI11 could modify an intermediate that it does not normally encounter. These findings indicate that substrate promiscuity varies among trichothecene biosynthetic P450s. One structural feature that likely impacts the ability of the P450s to use biosynthetic intermediates as substrates is the presence and absence of an oxygen atom attached to carbon atom 3 of EPT.


Subject(s)
Cytochrome P-450 Enzyme System , Trichothecenes , Substrate Specificity , Cytochrome P-450 Enzyme System/genetics , Secondary Metabolism
12.
Pestic Biochem Physiol ; 194: 105506, 2023 Aug.
Article in English | MEDLINE | ID: mdl-37532325

ABSTRACT

Fusarium head blight caused by Fusarium asiaticum is an important cereal crop disease, and the trichothecene mycotoxins produced by F. asiaticum can contaminate wheat grain, which is very harmful to humans and animals. To effectively control FHB in large areas, the application of fungicides is the major strategy; however, the application of different types of fungicides has varying influences on the accumulation of trichothecene mycotoxins in F. asiaticum. In this study, phenamacril inhibited trichothecene mycotoxin accumulation in F. asiaticum; however, carbendazim (N-1H-benzimidazol-2-yl-carbamic acid, methyl ester) induced trichothecene mycotoxin accumulation. Additionally, phenamacril led to a lower level of reactive oxygen species (ROS) by inducing gene expression of the catalase and superoxide dismutase (SOD) pathways in F. asiaticum, whereas carbendazim stimulated ROS accumulation by inhibiting gene expression of the catalase and SOD pathways. Based on these results, we conclude that phenamacril and carbendazim regulate trichothecene mycotoxin synthesis by affecting ROS levels in F. asiaticum.


Subject(s)
Fungicides, Industrial , Fusarium , Mycotoxins , Trichothecenes , Humans , Catalase/metabolism , Reactive Oxygen Species/metabolism , Fungicides, Industrial/pharmacology , Fungicides, Industrial/metabolism , Trichothecenes/pharmacology , Trichothecenes/metabolism , Mycotoxins/metabolism , Mycotoxins/pharmacology , Plant Diseases
13.
Toxins (Basel) ; 15(8)2023 07 31.
Article in English | MEDLINE | ID: mdl-37624241

ABSTRACT

Grain mold and stalk rot are among the fungal diseases that cause significant losses in sorghum worldwide and are caused by different Fusarium spp. The presence of Fusarium species in sorghum grains causes yield losses and mycotoxin contamination, which represents a risk to consumers. In this study, Fusarium graminearum species complex (FGSC) had a high incidence, followed by Fusarium fujikuroi species complex (FFSC) and F. incarnatum-equiseti species complex. Within FFSC, F. proliferatum, F. andiyazi, F. fujikuroi, F. thapsinum, F. verticillioides and F. subglutinans were identified, and this was the first report of F. fujikuroi in sorghum. The most frequent toxins found in sorghum samples were deoxynivalenol (DON) and zearalenone (ZEN). The presence of fumonisins and nivalenol (NIV) was detected at low levels. This study adds new knowledge about the occurrence of Fusarium species and mycotoxins in sorghum grains. Furthermore, this is the first report in Uruguay on fungicide sensitivity for Fusarium isolates from sorghum, which constitutes an important starting point for defining management practices to minimize fungal infection and mycotoxin contamination.


Subject(s)
Fumonisins , Fusarium , Mycotoxins , Sorghum , Uruguay , Edible Grain
14.
Toxins (Basel) ; 15(7)2023 07 18.
Article in English | MEDLINE | ID: mdl-37505729

ABSTRACT

Deoxynivalenol and nivalenol are major type B trichothecenes and the most frequently occurring mycotoxins worldwide. Their 3-ß-d-glucoside forms have recently become a safety management issue. These glucoside conjugates are converted back to the parent toxins during human digestion, but studies to confirm their bioavailability are lacking. In this study, a risk assessment was performed considering the bioavailability of glucoside conjugates. A literature review was conducted to compile the existing bioavailability studies of glucoside conjugates, and three exposure scenarios considering bioavailability were established. As a result of a risk assessment using deterministic and probabilistic methods, both the deoxynivalenol and nivalenol groups had safe levels of tolerable daily intake percentage (TDI%), not exceeding 100%. The TDI% for the nivalenol group was approximately 2-3 times higher than that for the deoxynivalenol group. Notably, infants showed higher TDI% than adults for both toxin groups. By food processing type, the overall TDI% was highest for raw material, followed by simple-processed and then fermented-processed. Since glucoside conjugates can be converted into parent toxins during the digestion process, a risk assessment considering bioavailability allows the more accurate evaluation of the risk level of glucoside conjugates and can direct their safety management in the future.


Subject(s)
Glucosides , Mycotoxins , Infant , Adult , Humans , Biological Availability , Food Contamination/analysis , Edible Grain/chemistry , Mycotoxins/analysis , Republic of Korea , Eating
15.
Food Chem Toxicol ; 178: 113874, 2023 Aug.
Article in English | MEDLINE | ID: mdl-37286030

ABSTRACT

The type B trichothecenes pollute food crops and have been associated to alimentary toxicosis resulted in emetic reaction in human and animal. This group of mycotoxins consists deoxynivalenol (DON) and four structurally related congeners: 3-acetyl-deoxynivalenol (3-ADON), 15-acetyl deoxynivalenol (15-ADON), nivalenol (NIV) and 4-acetyl-nivalenol (fusarenon X, FX). While emesis induced by intraperitoneally dosed to DON in the mink has been related to plasma up-grading of 5-hydroxytryptamine (5-HT) and neurotransmitters peptide YY (PYY), the impact of oral dosing with DON or its four congeners on secretion of these chemical substances have not been established. The aim of this work was to contraste emetic influence to type B trichothecene mycotoxins by orally dosing and involve these influence to PYY and 5-HT. All five toxins attracted marked emetic reaction that are relevant to elevated PYY and 5-HT. The reduction in vomiting induced by the five toxins and PYY was due to blocking of the neuropeptide Y2 receptor. The inhibition of the induced vomiting response by 5-HT and all five toxins is regulated by the 5-HT3 receptor inhibitor granisetron. In a word, our results indicate that PYY and 5-HT take a key role in the emetic reaction evoked by type B trichothecenes.


Subject(s)
Mycotoxins , Trichothecenes, Type B , Trichothecenes , Animals , Humans , Serotonin , Emetics/adverse effects , Peptide YY , Trichothecenes, Type B/adverse effects , Vomiting/chemically induced , Trichothecenes/toxicity , Mycotoxins/adverse effects , Mink
17.
Mycologia ; 115(4): 513-523, 2023.
Article in English | MEDLINE | ID: mdl-37192332

ABSTRACT

Genetic variation at variable number tandem repeat (VNTR) markers was used to assess population structure and diversity among 296 Fusarium graminearum isolates from northern Europe (Finland, northwestern Russia, and Norway), southern Europe (southwestern and western Russia), and Asia (Siberia and the Russian Far East). We identified at least two highly differentiated and geographically structured genetic populations (E1 and E2) in Eurasia (ΦPT = 0.35). Isolates from northern Europe were almost exclusively from the E1 population (95.6%) and had the 3ADON (3-acetyldeoxynivalenol) trichothecene genotype (97.3%). In contrast, all isolates from southern Europe were from the E2 population and 94.4% had the 15ADON (15-acetyldeoxynivalenol) genotype. The E2 population also predominated in the Asian sampling locations (92.7%) where 3ADON and 15ADON genotypes occurred at nearly equal frequencies. Southern European isolates were more closely related to those from Asia (ΦPT = 0.06) than to geographically closer populations from northern Europe (ΦPT ≥ 0.31). Northern European populations also harbored substantially less genetic diversity (Ne ≤ 2.1) than populations in southern Europe or Asia (Ne ≥ 3.4), indicative of a selective sweep or recent introduction and subsequent range expansion in northern Europe. Bayesian analyses incorporating previously described genetic populations from North America (NA1 and NA2) surprisingly identified NA2 and E2 as a single genetic population, consistent with hypotheses of a recent Eurasian origin for NA2. Additionally, more than 10% of the isolates from Asia and southern Europe were assigned to the NA1 population, indicating recent introductions of NA1 into parts of Eurasia. Collectively, these results demonstrate that there are at least three genetic populations of F. graminearum in the Northern Hemisphere and indicate that population-level diversity in Eurasia and North America has been shaped by recent transcontinental introductions.


Subject(s)
Fusarium , Bayes Theorem , Fusarium/genetics , North America , Asia, Eastern , Russia , Europe , Genetic Variation , Genotype
18.
Front Microbiol ; 14: 1148771, 2023.
Article in English | MEDLINE | ID: mdl-37138602

ABSTRACT

Among the genes involved in the biosynthesis of trichothecene (Tri genes), Tri6 and Tri10 encode a transcription factor with unique Cys2His2 zinc finger domains and a regulatory protein with no consensus DNA-binding sequences, respectively. Although various chemical factors, such as nitrogen nutrients, medium pH, and certain oligosaccharides, are known to influence trichothecene biosynthesis in Fusarium graminearum, the transcriptional regulatory mechanism of Tri6 and Tri10 genes is poorly understood. Particularly, culture medium pH is a major regulator in trichothecene biosynthesis in F. graminearum, but it is susceptible to metabolic changes posed by nutritional and genetic factors. Hence, appropriate precautions should be considered to minimize the indirect influence of pH on the secondary metabolism while studying the roles of nutritional and genetic factors on trichothecene biosynthesis regulation. Additionally, it is noteworthy that the structural changes of the trichothecene gene cluster core region exert considerable influence over the normal regulation of Tri gene expression. In this perspective paper, we consider a revision of our current understanding of the regulatory mechanism of trichothecene biosynthesis in F. graminearum and share our idea toward establishing a regulatory model of Tri6 and Tri10 transcription.

19.
Article in English | MEDLINE | ID: mdl-36912475

ABSTRACT

Deoxynivalenol (DON), a type B trichothecene mycotoxin contaminating grains, promotes nausea, emesis and anorexia. With DON exposure, circulating levels of intestinally derived satiation hormones, including glucagon-like peptide 1 (GLP-1) are elevated. To directly test whether GLP-1 signaling mediates the effects of DON, we examined the response of GLP-1 or GLP-1R-deficient mice to DON injection. We found comparable anorectic and conditioned taste avoidance learning responses in GLP-1/GLP-1R deficient mice compared to control littermates, suggesting that GLP-1 is not necessary for the effects of DON on food intake and visceral illness. We then used our previously published data from translating ribosome affinity purification with RNA sequencing (TRAP-seq) analysis of area postrema neurons that express the receptor for the circulating cytokine growth differentiation factor (GDF15), growth differentiation factor a-like (GFRAL). Interestingly, this analysis showed that a cell surface receptor for DON, calcium sensing receptor (CaSR), is heavily enriched in GFRAL neurons. Given that GDF15 potently reduces food intake and can cause visceral illness by signaling through GFRAL neurons, we hypothesized that DON may also signal by activating CaSR on GFRAL neurons. Indeed, circulating GDF15 levels are elevated after DON administration but both GFRAL knockout and GFRAL neuron-ablated mice exhibited similar anorectic and conditioned taste avoidance responses compared to WT littermates. Thus, GLP-1 signaling and GFRAL signaling and neurons are not required for DON-induced visceral illness or anorexia.

20.
Toxins (Basel) ; 15(3)2023 03 16.
Article in English | MEDLINE | ID: mdl-36977113

ABSTRACT

T-2 toxin is a mycotoxin routinely found as a contaminant of cereal grains worldwide. A portable mass spectrometer was adapted to enable the detection of T-2 toxin in wheat and maize by APCI-MS. In order to facilitate rapid testing, a rapid cleanup was used. The method was able to detect T-2 toxin in soft white wheat, hard red wheat, and yellow dent maize and could be used to screen for T-2 at levels above 0.2 mg/kg. The HT-2 toxin was only detectable at very high levels (>0.9 mg/kg). Based on these results, the sensitivity was not sufficient to allow the application of the screening method to these commodities at levels recommended by the European Commission. With a cut-off level of 0.107 mg/kg, the method correctly classified nine of ten reference samples of wheat and maize. The results suggest that portable MS detection of T-2 toxin is feasible. However, additional research will be needed to develop an application sensitive enough to meet regulatory requirements.


Subject(s)
Mycotoxins , T-2 Toxin , T-2 Toxin/analysis , Triticum , Zea mays , Mycotoxins/analysis , Mass Spectrometry , Edible Grain/chemistry , Food Contamination/analysis
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