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1.
J Nat Med ; 77(2): 306-314, 2023 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-36635416

RESUMO

The genus Claviceps (Clavicipitaceae) is famous for producing ergot alkaloids (EAs) in sclerotia. EAs can cause ergotism, resulting in convulsions and necrosis when ingested, making these compounds a serious concern for food safety. Agroclavine (2), a typical Clavine-type EA, is a causative agent of ergotism and is listed as a compound to be monitored by the European Food Safety Authority. Clavine-type EAs are known to cause cytotoxicity, but the mechanism has not been elucidated. We performed annexin V and PI double-staining followed by flow cytometric analysis to detect apoptosis in HepG2 and PANC-1 cells after exposure to Clavine-type EAs. Clavine-type EAs reduced cell viability and induced apoptosis in both cell lines. We then performed LC-MS analysis of EAs from 41 sclerotia samples of Claviceps collected in Japan. 24 out of 41 sclerotia extracts include peptide-type EAs (ergosine/inine: 4/4', ergotamine: 5, ergocornine/inine: 6/6', α-ergocryptine/inine: 8/8', and ergocristine/inine: 9/9') and 19 sclerotia extracts among 24 sclerotia detected peptide type EAs include Clavine-type EAs (pyroclavine: 1, agroclavine: 2, festuclavine: 3) by LC-MS. We then performed a metabolomic analysis of the EAs in the sclerotia using principal component analysis (PCA). The PCA score plots calculated for EAs suggested the existence of four groups with different EA production patterns. One of the groups was formed by the contribution of Clavine-type EAs. These results suggest that Clavine-type EAs are a family of compounds requiring attention in food safety and livestock production in Japan.


Assuntos
Claviceps , Alcaloides de Claviceps , Ergotismo , Humanos , Alcaloides de Claviceps/análise , Alcaloides de Claviceps/química , Japão , Claviceps/química , Claviceps/metabolismo , Peptídeos , Apoptose
2.
Molecules ; 27(21)2022 Oct 28.
Artigo em Inglês | MEDLINE | ID: mdl-36364148

RESUMO

Ergot is the spore form of the fungus Claviceps purpurea. Ergot alkaloids are indole compounds that are biosynthetically derived from L-tryptophan and represent the largest group of fungal nitrogen metabolites found in nature. The common part of ergot alkaloids is lysergic acid. This review shows the importance of lysergic acid as a representative of ergot alkaloids. The subject of ergot and its alkaloids is presented, with a particular focus on lysergic acid. All methods of total lysergic acid synthesis-through Woodward, Hendrickson, and Szantay intermediates and Heck coupling methods-are presented. The topic of biosynthesis is also discussed.


Assuntos
Claviceps , Alcaloides de Claviceps , Ácido Lisérgico , Ácido Lisérgico/metabolismo , Claviceps/metabolismo
3.
Metab Eng ; 69: 198-208, 2022 01.
Artigo em Inglês | MEDLINE | ID: mdl-34902590

RESUMO

Privileged ergot alkaloids (EAs) produced by the fungal genus Claviceps are used to treat a wide range of diseases. However, their use and research have been hampered by the challenging genetic engineering of Claviceps. Here we systematically refactored and rationally engineered the EA biosynthetic pathway in heterologous host Aspergillus nidulans by using a Fungal-Yeast-Shuttle-Vector protocol. The obtained strains allowed the production of diverse EAs and related intermediates, including prechanoclavine (PCC, 333.8 mg/L), chanoclavine (CC, 241.0 mg/L), agroclavine (AC, 78.7 mg/L), and festuclavine (FC, 99.2 mg/L), etc. This fungal platform also enabled the access to the methyl-oxidized EAs (MOEAs), including elymoclavine (EC), lysergic acid (LA), dihydroelysergol (DHLG), and dihydrolysergic acid (DHLA), by overexpressing a P450 enzyme CloA. Furthermore, by optimizing the P450 electron transfer (ET) pathway and using multi-copy of cloA, the titers of EC and DHLG have been improved by 17.3- and 9.4-fold, respectively. Beyond our demonstration of A. nidulans as a robust platform for EA overproduction, our study offers a proof of concept for engineering the eukaryotic P450s-contained biosynthetic pathways in a filamentous fungal host.


Assuntos
Claviceps , Alcaloides de Claviceps , Vias Biossintéticas/genética , Claviceps/genética , Claviceps/metabolismo , Sistema Enzimático do Citocromo P-450/genética , Sistema Enzimático do Citocromo P-450/metabolismo , Alcaloides de Claviceps/genética , Alcaloides de Claviceps/metabolismo , Saccharomyces cerevisiae/metabolismo
4.
Toxins (Basel) ; 13(12)2021 12 02.
Artigo em Inglês | MEDLINE | ID: mdl-34941699

RESUMO

Research into ergot alkaloid production in major cereal cash crops is crucial for furthering our understanding of the potential toxicological impacts of Claviceps purpurea upon Canadian agriculture and to ensure consumer safety. An untargeted metabolomics approach profiling extracts of C. purpurea sclerotia from four different grain crops separated the C. purpurea strains into two distinct metabolomic classes based on ergot alkaloid content. Variances in C. purpurea alkaloid profiles were correlated to genetic differences within the lpsA gene of the ergot alkaloid biosynthetic gene cluster from previously published genomes and from newly sequenced, long-read genome assemblies of Canadian strains. Based on gene cluster composition and unique polymorphisms, we hypothesize that the alkaloid content of C. purpurea sclerotia is currently undergoing adaptation. The patterns of lpsA gene diversity described in this small subset of Canadian strains provides a remarkable framework for understanding accelerated evolution of ergot alkaloid production in Claviceps purpurea.


Assuntos
Claviceps/genética , Alcaloides de Claviceps/biossíntese , Micotoxinas/química , Canadá , Claviceps/metabolismo , Grão Comestível/microbiologia , Alcaloides de Claviceps/genética , Variação Genética , Micotoxinas/genética , Secale/microbiologia , Triticale/microbiologia , Triticum/microbiologia
5.
Toxins (Basel) ; 13(11)2021 11 13.
Artigo em Inglês | MEDLINE | ID: mdl-34822583

RESUMO

Ergot fungi (Claviceps spp.) are infamous for producing sclerotia containing a wide spectrum of ergot alkaloids (EA) toxic to humans and animals, making them nefarious villains in the agricultural and food industries, but also treasures for pharmaceuticals. In addition to three classes of EAs, several species also produce paspaline-derived indole diterpenes (IDT) that cause ataxia and staggers in livestock. Furthermore, two other types of alkaloids, i.e., loline (LOL) and peramine (PER), found in Epichloë spp., close relatives of Claviceps, have shown beneficial effects on host plants without evidence of toxicity to mammals. The gene clusters associated with the production of these alkaloids are known. We examined genomes of 53 strains of 19 Claviceps spp. to screen for these genes, aiming to understand the evolutionary patterns of these genes across the genus through phylogenetic and DNA polymorphism analyses. Our results showed (1) varied numbers of eas genes in C. sect. Claviceps and sect. Pusillae, none in sect. Citrinae, six idt/ltm genes in sect. Claviceps (except four in C. cyperi), zero to one partial (idtG) in sect. Pusillae, and four in sect. Citrinae, (2) two to three copies of dmaW, easE, easF, idt/ltmB, itd/ltmQ in sect. Claviceps, (3) frequent gene gains and losses, and (4) an evolutionary hourglass pattern in the intra-specific eas gene diversity and divergence in C. purpurea.


Assuntos
Claviceps/genética , Alcaloides de Claviceps/biossíntese , Genes Fúngicos/genética , Alcaloides Indólicos/isolamento & purificação , Claviceps/metabolismo , Evolução Molecular , Família Multigênica , Filogenia
6.
Toxins (Basel) ; 13(5)2021 05 11.
Artigo em Inglês | MEDLINE | ID: mdl-34064772

RESUMO

Ergot alkaloids are mycotoxins formed by fungi of the Claviceps genus, which are some of the most common contaminants of food and feed worldwide. These toxins are a structurally heterogeneous group of compounds, sharing an ergoline backbone. Six structures and their corresponding stereoisomers are typically quantified by either HPLC-FLD or HPLC-MS/MS and the values subsequently summed up to determine the total ergot alkaloid content. For the development of a screening method targeting all ergot alkaloids simultaneously, the alkaloids need to be transferred to one homogeneous structure: a lysergic acid derivative. In this study, two promising cleaving methods-acidic esterification and hydrazinolysis-are compared, using dihydroergocristine as a model compound. While the acidic esterification proved to be unsuitable, due to long reaction times and oxidation sensitivity, hydrazinolysis reached a quantitative yield in 40‒60 min. Parallel workup of several samples is possible. An increasing effect on the reaction rate by the addition of ammonium iodide was demonstrated. Application of hydrazinolysis to a major ergot alkaloid mix solution showed that all ergopeptines were cleaved, but ergometrine/-inine was barely affected. Still, hydrazinolysis is a suitable tool for the development of a sum parameter screening method for ergot alkaloids in food and feed.


Assuntos
Claviceps/metabolismo , Alcaloides de Claviceps/análise , Micotoxinas/análise , Cromatografia Líquida de Alta Pressão , Alcaloides de Claviceps/química , Hidrazinas/química , Micotoxinas/química , Estereoisomerismo , Espectrometria de Massas em Tandem
7.
N Biotechnol ; 61: 69-79, 2021 Mar 25.
Artigo em Inglês | MEDLINE | ID: mdl-33188977

RESUMO

The parasitic fungus Claviceps purpurea has been used for decades by the pharmaceutical industry as a valuable producer of ergot alkaloids. As the biosynthetic pathway of ergot alkaloids involves a common precursor L-tryptophan, targeted genetic modification of the related genes may improve production yield. In this work, the S76L mutated version of the trpE gene encoding anthranilate synthase was constitutively overexpressed in the fungus with the aim of overcoming feedback inhibition of the native enzyme by an excess of tryptophan. In another approach, the dmaW gene encoding dimethylallyltryptophan synthase, which produces a key intermediate for the biosynthesis of ergot alkaloids, was also constitutively overexpressed. Each of the above manipulations led to a significant increase (up to 7-fold) in the production of ergot alkaloids in submerged cultures.


Assuntos
Claviceps/genética , Claviceps/metabolismo , Alcaloides de Claviceps/biossíntese , Triptofano/genética , Alcaloides de Claviceps/química , Perfilação da Expressão Gênica , Estrutura Molecular , Triptofano/metabolismo
8.
Fungal Genet Biol ; 145: 103481, 2020 12.
Artigo em Inglês | MEDLINE | ID: mdl-33130255

RESUMO

Claviceps purpurea is a plant pathogenic fungus which is still highly relevant in modern agriculture as it infects grasses such as rye and wheat. The disease caused by the consumption of contaminated grain or flour has been known since the Middle Ages and is termed ergotism. The main cause for the toxicity of this fungus is attributed to the ergot alkaloids. Apart from these alkaloids and the ergochromes known as ergot pigments, the secondary metabolism of C. purpurea is not well investigated. This study demonstrated the function of the polyketide synthase PKS7 in C. purpurea by determining the effect of its overexpression on metabolite profiles. For the first time, the depsides lecanoric acid, ethyl lecanorate, gerfelin, and C10-deoxy gerfelin were discovered as secondary metabolites of C. purpurea. Additionally, to estimate the contribution of isolated secondary metabolites to the toxic effects of C. purpurea, lecanoric acid, ethyl lecanorate, and orsellinic acid were tested on HepG2 and CCF-STTG1 cell lines. This study provides the first report on the function of C. purpurea PKS7 responsible for the production of depsides, among which lecanoric acid and ethyl lecanorate were identified as main secondary metabolites.


Assuntos
Claviceps/genética , Alcaloides de Claviceps/biossíntese , Policetídeo Sintases/genética , Salicilatos/metabolismo , Claviceps/metabolismo , Grão Comestível/genética , Grão Comestível/crescimento & desenvolvimento , Alcaloides de Claviceps/genética , Doenças das Plantas/genética , Doenças das Plantas/microbiologia , Triticum/microbiologia
9.
Sci Rep ; 10(1): 13475, 2020 08 10.
Artigo em Inglês | MEDLINE | ID: mdl-32778722

RESUMO

Rye is used as food, feed, and for bioenergy production and remain an essential grain crop for cool temperate zones in marginal soils. Ergot is known to cause severe problems in cross-pollinated rye by contamination of harvested grains. The molecular response of the underlying mechanisms of this disease is still poorly understood due to the complex infection pattern. RNA sequencing can provide astonishing details about the transcriptional landscape, hence we employed a transcriptomic approach to identify genes in the underlying mechanism of ergot infection in rye. In this study, we generated de novo assemblies from twelve biological samples of two rye hybrids with identified contrasting phenotypic responses to ergot infection. The final transcriptome of ergot susceptible (DH372) and moderately ergot resistant (Helltop) hybrids contain 208,690 and 192,116 contigs, respectively. By applying the BUSCO pipeline, we confirmed that these transcriptome assemblies contain more than 90% of gene representation of the available orthologue groups at Virdiplantae odb10. We employed a de novo assembled and the draft reference genome of rye to count the differentially expressed genes (DEGs) between the two hybrids with and without inoculation. The gene expression comparisons revealed that 228 genes were linked to ergot infection in both hybrids. The genome ontology enrichment analysis of DEGs associated them with metabolic processes, hydrolase activity, pectinesterase activity, cell wall modification, pollen development and pollen wall assembly. In addition, gene set enrichment analysis of DEGs linked them to cell wall modification and pectinesterase activity. These results suggest that a combination of different pathways, particularly cell wall modification and pectinesterase activity contribute to the underlying mechanism that might lead to resistance against ergot in rye. Our results may pave the way to select genetic material to improve resistance against ergot through better understanding of the mechanism of ergot infection at molecular level. Furthermore, the sequence data and de novo assemblies are valuable as scientific resources for future studies in rye.


Assuntos
Secale/genética , Secale/metabolismo , Claviceps/genética , Claviceps/metabolismo , Expressão Gênica/genética , Perfilação da Expressão Gênica/métodos , Regulação da Expressão Gênica de Plantas/genética , Anotação de Sequência Molecular , Doenças das Plantas/genética , Transcriptoma
10.
Mycologia ; 112(2): 230-243, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31910144

RESUMO

Claviceps species affecting Paspalum spp. are a serious problem, as they infect forage grasses such as Paspalum dilatatum and P. plicatulum, producing the ergot disease. The ascomycete C. paspali is known to be the pathogen responsible for this disease in both grasses. This fungus produces alkaloids, including ergot alkaloids and indole-diterpenes, that have potent neurotropic activities in mammals. A total of 32 isolates from Uruguay were obtained from infected P. dilatatum and P. plicatulum. Isolates were phylogenetically identified using partial sequences of the genes coding for the second largest subunit of RNA polymerase subunit II (RPB2), translation elongation factor 1-α (TEF1), ß-tubulin (TUB2), and the nuc rDNA 28S subunit (28S). Isolates were also genotyped by randomly amplified polymorphic DNA (RAPD) and presence of genes within the ergot alkaloid (EAS) and indole-diterpene (IDT) biosynthetic gene clusters. This study represents the first genetic characterization of several isolates of C. paspali. The results from this study provide insight into the genetic and genotypic diversity of Claviceps paspali present in P. dilatatum and suggest that isolates from P. plicatulum could be considered an ecological subspecies or specialized variant of C. paspali. Some of these isolates show hypothetical alkaloid genotypes never reported before.


Assuntos
Claviceps/genética , Alcaloides de Claviceps/genética , Alcaloides/genética , Claviceps/classificação , Claviceps/metabolismo , Diterpenos , Genótipo , Técnicas de Genotipagem , Especificidade de Hospedeiro , Indóis , Família Multigênica , Paspalum/microbiologia , Filogenia , Doenças das Plantas/microbiologia , Técnica de Amplificação ao Acaso de DNA Polimórfico
11.
Molecules ; 25(2)2020 Jan 14.
Artigo em Inglês | MEDLINE | ID: mdl-31947568

RESUMO

Ergometrine and methylergometrine are two alkaloids that are used as maleate salts for the prevention and control of postpartum hemorrhage. Although the two molecules have been known for a long time, few and discordant crystallographic and NMR spectroscopic data are available in the literature. With the aim of providing more conclusive data, we performed a careful NMR study for the complete assignment of the 1H, 13C, and 15N NMR signals of ergometrine, methylergometrine, and their maleate salts. This information allowed for a better definition of their conformational equilibria. In addition, the stereochemistry and the intermolecular interactions in the solid state of the two maleate salts were deeply investigated by means of single-crystal X-ray diffraction, showing the capability of these derivatives to act as both hydrogen-bond donors and acceptors, and evidencing a correlation between the number of intermolecular interactions and their different solubility.


Assuntos
Claviceps/metabolismo , Ergonovina/química , Alcaloides de Claviceps/química , Metilergonovina/química , Cristalografia por Raios X , Espectroscopia de Ressonância Magnética , Modelos Moleculares , Estrutura Molecular
12.
Biotechnol Lett ; 41(12): 1439-1449, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31659576

RESUMO

OBJECTIVE: To enhance ergot alkaloid production of Claviceps purpurea Cp-1 strain by epigenetic modification approach. RESULTS: The chemical epigenetic modifiers were screened to promote ergot alkaloid production of the Cp-1 strain. The histone deacetylase inhibitor suberoylanilide hydroxamic acid (SAHA) was found to significantly enhance the alkaloid productivity of the strain. Particularly, the titers of total ergot alkaloids were gradually increased with the increase of SAHA concentration in the fermentation medium, and the highest production of ergot alkaloids could be achieved at the concentration of 500 µM SAHA. Specially, the titers of ergometrine and total ergot alkaloids were as high as 95.4 mg/L and 179.7 mg/L, respectively, which were twice of those of the control. Furthermore, the mRNA expression levels of the most functional genes in the ergot alkaloid synthesis (EAS) gene cluster were up-regulated under SAHA treatment. It was proposed that SAHA might increase histone acetylation in the EAS gene cluster region in the chromosome, which would loosen the chromosome structure, and subsequently up-regulate the mRNA expression levels of genes involved in the biosynthesis of ergot alkaloids, thereby resulting in the markedly increase in the production of ergot alkaloids. CONCLUSIONS: The ergot alkaloid production by the C. purpurea Cp-1 strain can be effectively increased by the application of histone deacetylase inhibitor. Our work provides a reference for using the chemical epigenetic modifiers to improve SM production in other fungi.


Assuntos
Vias Biossintéticas/genética , Claviceps/genética , Claviceps/metabolismo , Epigênese Genética , Alcaloides de Claviceps/biossíntese , Vias Biossintéticas/efeitos dos fármacos , Claviceps/efeitos dos fármacos , Fermentação , Inibidores de Histona Desacetilases/metabolismo
13.
J Agric Food Chem ; 65(49): 10703-10710, 2017 Dec 13.
Artigo em Inglês | MEDLINE | ID: mdl-29172518

RESUMO

Biosynthesis of the dihydrogenated forms of ergot alkaloids is of interest because many of the ergot alkaloids used as pharmaceuticals may be derived from dihydrolysergic acid (DHLA) or its precursor dihydrolysergol. The maize (Zea mays) ergot pathogen Claviceps gigantea has been reported to produce dihydrolysergol, a hydroxylated derivative of the common ergot alkaloid festuclavine. We hypothesized expression of C. gigantea cloA in a festuclavine-accumulating mutant of the fungus Neosartorya fumigata would yield dihydrolysergol because the P450 monooxygenase CloA from other fungi performs similar oxidation reactions. We engineered such a strain, and high performance liquid chromatography and liquid chromatography-mass spectrometry analyses demonstrated the modified strain produced DHLA, the fully oxidized product of dihydrolysergol. Accumulation of high concentrations of DHLA in field-collected C. gigantea sclerotia and discovery of a mutation in the gene lpsA, downstream from DHLA formation, supported our finding that DHLA rather than dihydrolysergol is the end product of the C. gigantea pathway.


Assuntos
Claviceps/metabolismo , Alcaloides de Claviceps/biossíntese , Zea mays/microbiologia , Cromatografia Líquida de Alta Pressão/métodos , Expressão Gênica , Ácido Lisérgico/análogos & derivados , Ácido Lisérgico/química , Espectrometria de Massas/métodos , Oxigenases de Função Mista/metabolismo , Mutação , Metabolismo Secundário , Transformação Genética
14.
BMC Genomics ; 18(1): 273, 2017 04 04.
Artigo em Inglês | MEDLINE | ID: mdl-28372538

RESUMO

BACKGROUND: The economically important Ergot fungus Claviceps purpurea is an interesting biotrophic model system because of its strict organ specificity (grass ovaries) and the lack of any detectable plant defense reactions. Though several virulence factors were identified, the exact infection mechanisms are unknown, e.g. how the fungus masks its attack and if the host detects the infection at all. RESULTS: We present a first dual transcriptome analysis using an RNA-Seq approach. We studied both, fungal and plant gene expression in young ovaries infected by the wild-type and two virulence-attenuated mutants. We can show that the plant recognizes the fungus, since defense related genes are upregulated, especially several phytohormone genes. We present a survey of in planta expressed fungal genes, among them several confirmed virulence genes. Interestingly, the set of most highly expressed genes includes a high proportion of genes encoding putative effectors, small secreted proteins which might be involved in masking the fungal attack or interfering with host defense reactions. As known from several other phytopathogens, the C. purpurea genome contains more than 400 of such genes, many of them clustered and probably highly redundant. Since the lack of effective defense reactions in spite of recognition of the fungus could very well be achieved by effectors, we started a functional analysis of some of the most highly expressed candidates. However, the redundancy of the system made the identification of a drastic effect of a single gene most unlikely. We can show that at least one candidate accumulates in the plant apoplast. Deletion of some candidates led to a reduced virulence of C. purpurea on rye, indicating a role of the respective proteins during the infection process. CONCLUSIONS: We show for the first time that- despite the absence of effective plant defense reactions- the biotrophic pathogen C. purpurea is detected by its host. This points to a role of effectors in modulation of the effective plant response. Indeed, several putative effector genes are among the highest expressed genes in planta.


Assuntos
Claviceps/genética , Flores/microbiologia , Doenças das Plantas/microbiologia , Secale/microbiologia , Claviceps/metabolismo , Resistência à Doença/genética , Flores/genética , Flores/metabolismo , Regulação Fúngica da Expressão Gênica , Regulação da Expressão Gênica de Plantas , Genes Fúngicos , Genes de Plantas , Interações Hospedeiro-Patógeno , Secale/genética , Secale/metabolismo , Transcriptoma , Fatores de Virulência/genética
15.
Phytopathology ; 107(5): 504-518, 2017 May.
Artigo em Inglês | MEDLINE | ID: mdl-28168931

RESUMO

Ergot alkaloids are highly diverse in structure, exhibit diverse effects on animals, and are produced by diverse fungi in the phylum Ascomycota, including pathogens and mutualistic symbionts of plants. These mycotoxins are best known from the fungal family Clavicipitaceae and are named for the ergot fungi that, through millennia, have contaminated grains and caused mass poisonings, with effects ranging from dry gangrene to convulsions and death. However, they are also useful sources of pharmaceuticals for a variety of medical purposes. More than a half-century of research has brought us extensive knowledge of ergot-alkaloid biosynthetic pathways from common early steps to several taxon-specific branches. Furthermore, a recent flurry of genome sequencing has revealed the genomic processes underlying ergot-alkaloid diversification. In this review, we discuss the evolution of ergot-alkaloid biosynthesis genes and gene clusters, including roles of gene recruitment, duplication and neofunctionalization, as well as gene loss, in diversifying structures of clavines, lysergic acid amides, and complex ergopeptines. Also reviewed are prospects for manipulating ergot-alkaloid profiles to enhance suitability of endophytes for forage grasses.


Assuntos
Claviceps/genética , Alcaloides de Claviceps/genética , Evolução Molecular , Hypocreales/genética , Doenças das Plantas/microbiologia , Poaceae/microbiologia , Vias Biossintéticas , Claviceps/química , Claviceps/metabolismo , Endófitos , Alcaloides de Claviceps/química , Alcaloides de Claviceps/metabolismo , Genômica , Hypocreales/química , Hypocreales/metabolismo , Família Multigênica , Micotoxinas/química , Micotoxinas/genética , Micotoxinas/metabolismo , Simbiose
16.
N Biotechnol ; 33(5 Pt B): 743-754, 2016 Sep 25.
Artigo em Inglês | MEDLINE | ID: mdl-26827914

RESUMO

The fungus Claviceps purpurea is a biotrophic phytopathogen widely used in the pharmaceutical industry for its ability to produce ergot alkaloids (EAs). The fungus attacks unfertilized ovaries of grasses and forms sclerotia, which represent the only type of tissue where the synthesis of EAs occurs. The biosynthetic pathway of EAs has been extensively studied; however, little is known concerning its regulation. Here, we present the quantitative transcriptome analysis of the sclerotial and mycelial tissues providing a comprehensive view of transcriptional differences between the tissues that produce EAs and those that do not produce EAs and the pathogenic and non-pathogenic lifestyle. The results indicate metabolic changes coupled with sclerotial differentiation, which are likely needed as initiation factors for EA biosynthesis. One of the promising factors seems to be oxidative stress. Here, we focus on the identification of putative transcription factors and regulators involved in sclerotial differentiation, which might be involved in EA biosynthesis. To shed more light on the regulation of EA composition, whole transcriptome analysis of four industrial strains differing in their alkaloid spectra was performed. The results support the hypothesis proposing the composition of the amino acid pool in sclerotia to be an important factor regulating the final structure of the ergopeptines produced by Claviceps purpurea.


Assuntos
Claviceps/genética , Claviceps/metabolismo , Alcaloides de Claviceps/biossíntese , Sequência de Aminoácidos , Biotecnologia , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Expressão Gênica , Perfilação da Expressão Gênica , Genes Fúngicos , Microbiologia Industrial , Estresse Oxidativo , Peptídeo Sintases/genética , Peptídeo Sintases/metabolismo , Polimorfismo de Nucleotídeo Único , Homologia de Sequência de Aminoácidos
17.
Fungal Biol ; 120(1): 104-10, 2016 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-26693687

RESUMO

A novel secondary metabolite from the sclerotia of Claviceps purpurea (Fr.) Tul. is described; the structure is based on (1)H and (13)C NMR spectroscopy and electrospray mass spectrometry. It has an elemental composition C10H16N2O7 and is comprised mainly of proline and alanine moieties, although without peptide linkage. Notably, these amino-acids are also components of the cyclic tripeptide side chain of several classic ergoline alkaloids. Designated as purpurolic acid, the new compound is the principal free amino-acid in ergot and its natural abundance exceeds that of the ergoline alkaloids with which it accumulates in parallel during parasitic development. In contrast, it does not accumulate in the fungus in axenic culture, even when ergotamine is synthesised. The extent to which the compound is a metabolite of other ergot fungi worldwide is unknown. Biological activity and metabolic significance also remain unknown, but purpurolic acid could become a biomarker for detection of ergot contamination in agricultural products of temperate latitudes.


Assuntos
Alcaloides/química , Claviceps/metabolismo , Alcaloides/metabolismo , Claviceps/química , Espectroscopia de Ressonância Magnética , Espectrometria de Massas , Estrutura Molecular
18.
Toxins (Basel) ; 7(5): 1431-56, 2015 Apr 28.
Artigo em Inglês | MEDLINE | ID: mdl-25928134

RESUMO

The grass parasitic fungus Claviceps purpurea sensu lato produces sclerotia with toxic indole alkaloids. It constitutes several genetic groups with divergent habitat preferences that recently were delimited into separate proposed species. We aimed to 1) analyze genetic variation of C. purpurea sensu lato in Norway, 2) characterize the associated indole alkaloid profiles, and 3) explore relationships between genetics, alkaloid chemistry and ecology. Approximately 600 sclerotia from 14 different grass species were subjected to various analyses including DNA sequencing and HPLC-MS. Molecular results, supported by chemical and ecological data, revealed one new genetic group (G4) in addition to two of the three known; G1 (C. purpurea sensu stricto) and G2 (C. humidiphila). G3 (C. spartinae) was not found. G4, which was apparently con-specific with the recently described C. arundinis sp. nov, was predominantly found in very wet habitats on Molinia caerulea and infrequently in saline habitats on Leymus arenarius. Its indole-diterpene profile resembled G2, while its ergot alkaloid profile differed from G2 in high amounts of ergosedmam. In contrast to G1, indole-diterpenes were consistently present in G2 and G4. Our study supports and complements the newly proposed species delimitation of the C. purpurea complex, but challenges some species characteristics including host spectrum, habitat preferences and sclerotial floating ability.


Assuntos
Claviceps/genética , Claviceps/metabolismo , Alcaloides Indólicos/metabolismo , Poaceae/parasitologia , DNA Fúngico/genética , DNA Ribossômico/genética , Diterpenos/metabolismo , Variação Genética , Noruega , Filogenia , Análise de Sequência de DNA
19.
BMC Microbiol ; 15: 73, 2015 Mar 28.
Artigo em Inglês | MEDLINE | ID: mdl-25887091

RESUMO

BACKGROUND: Ergopeptines are a predominant class of ergot alkaloids produced by tall fescue grass endophyte Neotyphodium coenophialum or cereal pathogen Claviceps purpurea. The vasoconstrictive activity of ergopeptines makes them toxic for mammals, and they can be a problem in animal husbandry. RESULTS: We isolated an ergopeptine degrading bacterial strain, MTHt3, and classified it, based on its 16S rDNA sequence, as a strain of Rhodococcus erythropolis (Nocardiaceae, Actinobacteria). For strain isolation, mixed microbial cultures were obtained from artificially ergot alkaloid-enriched soil, and provided with the ergopeptine ergotamine in mineral medium for enrichment. Individual colonies derived from such mixed cultures were screened for ergotamine degradation by high performance liquid chromatography and fluorescence detection. R. erythropolis MTHt3 converted ergotamine to ergine (lysergic acid amide) and further to lysergic acid, which accumulated as an end product. No other tested R. erythropolis strain degraded ergotamine. R. erythropolis MTHt3 degraded all ergopeptines found in an ergot extract, namely ergotamine, ergovaline, ergocristine, ergocryptine, ergocornine, and ergosine, but the simpler lysergic acid derivatives agroclavine, chanoclavine, and ergometrine were not degraded. Temperature and pH dependence of ergotamine and ergine bioconversion activity was different for the two reactions. CONCLUSIONS: Degradation of ergopeptines to ergine is a previously unknown microbial reaction. The reaction end product, lysergic acid, has no or much lower vasoconstrictive activity than ergopeptines. If the genes encoding enzymes for ergopeptine catabolism can be cloned and expressed in recombinant hosts, application of ergopeptine and ergine degrading enzymes for reduction of toxicity of ergot alkaloid-contaminated animal feed may be feasible.


Assuntos
Alcaloides de Claviceps/metabolismo , Ácido Lisérgico/metabolismo , Rhodococcus/metabolismo , Animais , Biotransformação , Claviceps/metabolismo , Análise por Conglomerados , DNA Bacteriano/química , DNA Bacteriano/genética , DNA Ribossômico/química , DNA Ribossômico/genética , Epichloe/metabolismo , Mamíferos , Dados de Sequência Molecular , Filogenia , RNA Ribossômico 16S/genética , Análise de Sequência de DNA
20.
Arch Microbiol ; 197(5): 701-13, 2015 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-25796201

RESUMO

Ergot alkaloids are important as mycotoxins or as drugs. Naturally occurring ergot alkaloids as well as their semisynthetic derivatives have been used as pharmaceuticals in modern medicine for decades. We identified 196 putative ergot alkaloid biosynthetic genes belonging to at least 31 putative gene clusters in 31 fungal species by genome mining of the 360 available genome sequences of ascomycetous fungi with known proteins. Detailed analysis showed that these fungi belong to the families Aspergillaceae, Clavicipitaceae, Arthrodermataceae, Helotiaceae and Thermoascaceae. Within the identified families, only a small number of taxa are represented. Literature search revealed a large diversity of ergot alkaloid structures in different fungi of the phylum Ascomycota. However, ergot alkaloid accumulation was only observed in 15 of the sequenced species. Therefore, this study provides genetic basis for further study on ergot alkaloid production in the sequenced strains.


Assuntos
Ascomicetos/metabolismo , Alcaloides de Claviceps/biossíntese , Micotoxinas/biossíntese , Arthrodermataceae/classificação , Arthrodermataceae/genética , Arthrodermataceae/metabolismo , Ascomicetos/classificação , Ascomicetos/genética , Sequência de Bases , Claviceps/classificação , Claviceps/genética , Claviceps/metabolismo , Alcaloides de Claviceps/genética , Genes Fúngicos , Família Multigênica , Filogenia , Alinhamento de Sequência
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