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1.
Phytochemistry ; 192: 112978, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34678625

RESUMO

Chemical epigenetic manipulation of a deep-sea-derived Eutypella sp. fungus by the co-treatment with a histonedeacetylase inhibitor (suberohydroxamic acid, SBHA) and a DNA methyltransferase inhibitor (5-azacytidine, 5-Aza), resulted in the activation of a sesquiterpene-related biosynthetic gene cluster. Chromatographic separation of the elicitor-treated cultures led the isolation of 21 sesquiterpenes, including 17 undescribed compounds, eutypeterpenes A-Q. Their structures were identified by the extensive analysis of the spectroscopic data, including the single-crystal X-ray diffraction, chemical conversion, and the calculated NMR and ECD data for configurational assignments. Eutypeterpene A is a first bergamotene-type sesquiterpene incorporated with a dioxolanone unit, and eutypeterpenes O-Q with a cyclopentane ring represent an undescribed subtype of sesquiterpenes. The bioassay results showed that most compounds exert inhibitory effects against the lipopolysaccharide (LPS)-induced NO production in RAW 264.7 macrophages, and eutypeterpene N is the most active. This study demonstrates that the epigenetic manipulation is an effective approach to trigger the production of cryptic metabolites from deep-sea derived fungus. The significant inhibition against LPS-induced NO production in vitro suggests eutypeterpenes to be potential for the development as anti-inflammatory agents.


Assuntos
Sesquiterpenos , Xylariales , Epigênese Genética , Lipopolissacarídeos , Estrutura Molecular , Sesquiterpenos/farmacologia
2.
J Agric Food Chem ; 69(37): 10893-10906, 2021 Sep 22.
Artigo em Inglês | MEDLINE | ID: mdl-34516124

RESUMO

To discover microorganisms that naturally possess chemical weapons against the phytopathogen Fusarium oxysporum, the biological and chemical diversity of plant leaf endophytes was investigated. Endophytes were isolated from the palm tree Astrocaryum sciophyllum collected in pristine forests of French Guiana. Several Xylariaceae inhibited the growth of F. oxysporum and were further explored. Antifungal specialized metabolites were isolated from the Xylariaceae BSNB-0294 strain in confrontation with the phytopathogen and led to the identification of undescribed compounds, i.e., two depsipeptides named xylariaceins, two metabolites containing a 3-imidazolinone moiety, and four new compounds including a nitro-phenylpropanamide and three phenylalanine analogues named xylariains A-D. In parallel, the chemical investigation of the phytopathogen during the coculture led to the identification of an unknown compound, which we named focicin. The production of focicin was exacerbated during the competition. Matrix-assisted laser desorption/ionization coupled to time-of-flight mass spectometry (MALDI-TOF MS) imaging of the competition between BSNB-0294 (endophytic strain) and F. oxysporum f.sp. ciceris (phytopathogen) highlighted time-dependent chemical interactions between the two microorganisms.


Assuntos
Fusarium , Xylariales , Endófitos , Doenças das Plantas , Árvores
3.
Arch Microbiol ; 203(10): 6119-6129, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34550408

RESUMO

In the process of studying the diversity of Xylariales in China, three species owning characteristics of Graphostromataceae were observed in China. Morphology of the described species with illustrations and their phylogeny based on regions of internal transcribed spacers (ITS), the second-largest subunit of the RNA polymerase II (RPB2), ß-tubulin (TUB2) and α-actin (ACT) are provided. Two new species and one new record from China are identified. Morphologically, Biscogniauxia glaucae sp. nov. differs from B. atropunctata var. maritima, B. citriformis var. macrospora, B. fuscella and B. mediterranea by its stromata with raised margins, clear outlines, punctate ostioles openings and ascospores which are equilateral with broadly rounded ends, a straight spore-length germ slit on the more concave side, lacking appendages and sheathes. Graphostroma guizhouensis is identified as a new species based on the multi-gene phylogenetic tree. Camillea broomeana with scanning electron microscope description of ascospores is illustrated as a new record from China. Cryptostroma is proposed in Graphostromataceae based on molecular data. Vivantia is accepted in Graphostromataceae based on its morphological characteristics and Nodulisporiurn anamorphs which are similar to those of Biscogniauxia.


Assuntos
Xylariales , China , DNA Fúngico/genética , DNA Ribossômico , Filogenia , Análise de Sequência de DNA , Xylariales/genética
4.
Phytochemistry ; 191: 112908, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34388664

RESUMO

The fungus Biscogniauxia whalleyi SWUF13-085 from the Graphostomataceae family was studied for potential anti-inflammatory and anticancer agents. A diverse array of natural products was identified. Six of which were undescribed compounds, including xylariterpenoids L-N, (1R,2S,6R,7S)-1,2-dihydroxy-α-bisabolol, 6-[(1R)-1-hydroxy-1-methyl-2-propenyl]-4-methoxy-3-methyl-2H-pyran-2-one and (1R*,4S*,5S*,7S*,10R*)-guaia-11 (12)-en-7,10-diol. Several of the isolated compounds such as bergamotene, guaiane and phthalide derivatives showed activity in both the inhibition of nitric oxide (NO) production in lipopolysaccharide (LPS)-stimulated RAW264.7 macrophage cells with IC50 values in the range of 2.48-10.82 µg/mL and anti-proliferation against HeLa cells with IC50 values in the range of 8.64-31.16 µg/mL. While compounds such as cerebrosides A and C only exhibited inhibitory effects on NO production with IC50 values in the range of 4.45-10.28 µg/mL.


Assuntos
Anti-Inflamatórios , Xylariales , Animais , Anti-Inflamatórios/farmacologia , Células HeLa , Humanos , Lipopolissacarídeos/farmacologia , Camundongos , Óxido Nítrico , Células RAW 264.7
5.
Appl Microbiol Biotechnol ; 105(10): 4225-4239, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33970316

RESUMO

Bioassay-guided fractionation of the organic extracts of the endophyte Daldinia eschscholtzii strain GsE13 led to the isolation of several phytotoxic compounds, including two chromenone and two chromanone derivatives: 5-hydroxy-8-methoxy-2-methyl-4H-chromen-4-one, 1; 5-hydroxy-2-methyl-4H-chromen-4-one, 2; 5-methoxy-2-methyl-chroman-4-one, 3; and 5-methoxy-2-methyl-chroman-4-ol, 4; as well as other aromatic compounds: 4,8-dihydroxy-1-tetralone, 5; 1,8-dimethoxynaphthalene, 6; and 4,9-dihydroxy-1,2,11,12-tetrahydroperyl-ene-3,10-quinone, 7. Compounds 1, 4, and 7 were isolated for the first time from D. eschscholtzii. The phytotoxicity of all the compounds was determined on germination, root growth, and oxygen uptake in seedlings of a monocotyledonous (Panicum miliaceum) and three dicotyledonous plants (Medicago sativa, Trifolium pratense, and Amaranthus hypochondriacus). In general, root growth was the most affected process in all four weeds, and chromenones 1 and 2 were the most phytotoxic compounds. Phytotoxins 1-4 inhibited basal oxygen consumption rate in isolated mitochondria from M. sativa seedlings and also caused serious damage to their membrane potential (ΔΨm) in percentages greater than 50% at concentrations lower than 2 mM. Based on these results, compounds 1-4 of endophytic origin could be promising for the development of new herbicides potentially useful in agriculture or for the synthesis of promising new molecules. KEY POINTS: • Endophytic fungus Daldinia eschscholtzii produces phytotoxic compounds. • Phytotoxins inhibit basal oxygen consumption rate in isolated M. sativa mitochondria. • Phytotoxins altered the mitochondrial membrane potential.


Assuntos
Herbicidas , Xylariales , Ascomicetos , Endófitos , Germinação , Herbicidas/toxicidade , Plântula
6.
Sci Rep ; 11(1): 7779, 2021 04 08.
Artigo em Inglês | MEDLINE | ID: mdl-33833332

RESUMO

Repetitive uses of antifungals result in a worldwide crisis of drug resistance; therefore, natural fungicides with minimal side-effects are currently sought after. This study aimed to investigate antifungal property of 19, 20-epoxycytochalasin Q (ECQ), derived from medicinal mushroom Xylaria sp. BCC 1067 of tropical forests. In a model yeast Saccharomyces cerevisiae, ECQ is more toxic in the erg6∆ strain, which has previously been shown to allow higher uptake of many hydrophilic toxins. We selected one pathway to study the effects of ECQ at very high levels on transcription: the ergosterol biosynthesis pathway, which is unlikely to be the primary target of ECQ. Ergosterol serves many functions that cholesterol does in human cells. ECQ's transcriptional effects were correlated with altered sterol and triacylglycerol levels. In the ECQ-treated Δerg6 strain, which presumably takes up far more ECQ than the wild-type strain, there was cell rupture. Increased actin aggregation and lipid droplets assembly were also found in the erg6∆ mutant. Thereby, ECQ is suggested to sensitize yeast cells lacking ERG6 through actin-targeting and consequently but not primarily led to disruption of lipid homeostasis. Investigation of cytochalasins may provide valuable insight with potential biopharmaceutical applications in treatments of fungal infection, cancer or metabolic disorder.


Assuntos
Actinas/antagonistas & inibidores , Antifúngicos/farmacologia , Citocalasinas/farmacologia , Metabolismo dos Lipídeos/efeitos dos fármacos , Saccharomyces cerevisiae/efeitos dos fármacos , Xylariales/metabolismo , Metiltransferases/genética , Saccharomyces cerevisiae/genética
7.
J Food Biochem ; 45(4): e13694, 2021 04.
Artigo em Inglês | MEDLINE | ID: mdl-33687093

RESUMO

Nondigestible polysaccharides are essential nutrients, which are also important bioactive constituents of mushrooms. This study aimed to investigate the physicochemical properties and anti-inflammatory effects of different polysaccharide components of Xylaria nigripes in lipopolysaccharides (LPS)-induced RAW264.7 macrophages. Results showed that X. nigripes nondigestible polysaccharide (XN) possessed a molecular weight of 910.7 kDa and mainly composed of glucose; it effectively suppressed NO, TNF-α, and IL-6 production. Based on molecular weight, two bioactive polysaccharide components (F1 and F2) were isolated from XN. F1 was a glucan with high molecular weight (885.2 kDa), whereas F2 was a low molecular weight heteropolysaccharide (24.5 kDa) composing of glucose, mannose, and galactose. F1 showed stronger inhibitory effects on NO, TNF-α, and IL-6 production than F2, however, its inhibitory effects were weaker than XN. Further analysis demonstrated that the combined treatment of F1 and F2 exhibited anti-inflammatory activity as good as XN, and they possessed synergistic effects on inhibiting pro-inflammatory mediator production. PRACTICAL APPLICATIONS: Polysaccharides are essential nutrients, and are major bioactive constituents of mushrooms. This study isolated two bioactive polysaccharide components from Xylaria nigripes, namely F1 and F2. F1 was a high molecular weight glucan, whereas F2 was a low molecular weight heteropolysaccharide. F1 showed stronger anti-inflammatory activity than F2, but was weaker than their combined treatment (F1 + F2). Different polysaccharide components were shown to possess synergistic anti-inflammatory effects, suggesting their importance in the formulation of polysaccharide-based products.


Assuntos
Polissacarídeos , Xylariales , Anti-Inflamatórios/farmacologia , Ascomicetos , Lipopolissacarídeos , Polissacarídeos/farmacologia
8.
Mycologia ; 113(2): 326-347, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33555993

RESUMO

Taproot decline (TRD) is a disease of soybean that has been reported recently from the southern United States (U.S.). Symptoms of TRD include foliar interveinal chlorosis followed by necrosis. Darkened, charcoal-colored areas of thin stromatic tissue are evident on the taproot and lateral roots along with areas of necrosis within the root and white mycelia within the pith. Upright stromata typical of Xylaria can be observed on crop debris and emerging from infested roots in fields where taproot decline is present, but these have not been determined to contain fertile perithecia. Symptomatic plant material was collected across the known range of the disease in the southern U.S., and the causal agent was isolated from roots. Four loci, ⍺-actin (ACT), ß-tubulin (TUB2), the nuclear rDNA internal transcribed spacers (nrITS), and the RNA polymerase subunit II (RPB2), were sequenced from representative isolates. Both maximum likelihood and Bayesian phylogenetic analyses showed consistent clustering of representative TRD isolates in a highly supported clade within the Xylaria arbuscula species complex in the "HY" clade of the family Xylariaceae, distinct from any previously described taxa. In order to understand the origin of this pathogen, we sequenced herbarium specimens previously determined to be "Xylaria arbuscula" based on morphology and xylariaceous endophytes collected in the southern U.S. Some historical specimens from U.S. herbaria collected in the southern region as saprophytes as well as a single specimen from Martinique clustered within the "TRD" clade in phylogenetic analyses, suggesting a possible shift in lifestyle. The remaining specimens that clustered within the family Xylariaceae, but outside of the "TRD" clade, are reported. Both morphological evidence and molecular evidence indicate that the TRD pathogen is a novel species, which is described as Xylaria necrophora.


Assuntos
Doenças das Plantas/microbiologia , Raízes de Plantas/microbiologia , Soja/microbiologia , Xylariales/genética , Xylariales/patogenicidade , Teorema de Bayes , DNA Fúngico/genética , DNA Ribossômico/genética , Variação Genética , Filogenia , Estados Unidos , Xylariales/classificação
9.
Artigo em Inglês | MEDLINE | ID: mdl-33416464

RESUMO

Fungal communities associated with macroalgae remain largely unexplored. To characterize algicolous fungal communities using culture dependent methods, macroalgae were collected from different sampling sites in the Ria de Aveiro estuary, Portugal. From a collection of 486 isolates that were obtained, 213 representative isolates were selected through microsatellite-primed PCR (MSP-PCR) fingerprinting analysis. The collection yielded 33 different genera, which were identified using the ITS region of the rDNA. The results revealed that the most abundant taxa in all collections were Acremonium-like species: Alternaria, Cladosporium, Leptobacillium and Penicillium. The fungal community composition varied with macroalgae species. Through multilocus phylogenetic analyses based on ITS, tub2, tef1-α and actA sequences, in addition to detailed morphological data, we propose Cladosporium rubrum sp. nov. (type strain=CMG 28=MUM 19.39) and Hypoxylon aveirense sp. nov. (type strain=CMG 29=MUM 19.40) as novel species.


Assuntos
Cladosporium/classificação , Estuários , Filogenia , Alga Marinha/microbiologia , Composição de Bases , Cladosporium/isolamento & purificação , DNA Fúngico/genética , DNA Espaçador Ribossômico/genética , Hypocreales/classificação , Hypocreales/isolamento & purificação , Técnicas de Tipagem Micológica , Penicillium/classificação , Penicillium/isolamento & purificação , Portugal , Análise de Sequência de DNA , Xylariales
10.
J Nat Prod ; 84(2): 466-473, 2021 02 26.
Artigo em Inglês | MEDLINE | ID: mdl-33491454

RESUMO

Five new tyrosine derivatives (1-5), one new phenylacetic acid derivative (6), two new quinazolinone analogues (7 and 8), one new naphthalenedicarboxylic acid (9), and one new 3,4-dihydroisocoumarin derivative (10), together with seven known compounds, were isolated from the fungus Xylaria sp. FM1005, which was isolated from Sinularia densa (leather coral) collected in the offshore region of the Big Island, Hawaii. The structures of compounds 1-10 were elucidated by extensive analysis of NMR spectroscopy, HRESIMS, and ECD data. Due to their structure similarity to the antiplatelet drug tirofiban, compounds 1-5 together with 6 were investigated for their antithrombotic activities. Compounds 1 and 2 strongly inhibited the binding of fibrinogen to purified integrin IIIb/IIa in a dose-dependent manner with the IC50 values of 0.89 and 0.61 µM, respectively, and compounds 1 and 2 did not show any cytotoxicity against A2780 and HEK 293 at 40 µM.


Assuntos
Antozoários/microbiologia , Fibrinolíticos/farmacologia , Complexo Glicoproteico GPIIb-IIIa de Plaquetas/antagonistas & inibidores , Xylariales/química , Animais , Linhagem Celular Tumoral , Fibrinolíticos/isolamento & purificação , Células HEK293 , Hawaii , Humanos , Masculino , Estrutura Molecular , Fenilacetatos/isolamento & purificação , Fenilacetatos/farmacologia , Quinazolinonas/isolamento & purificação , Quinazolinonas/farmacologia , Ratos Sprague-Dawley , Metabolismo Secundário , Tirosina/isolamento & purificação , Tirosina/farmacologia
11.
Microbiol Res ; 243: 126646, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33227681

RESUMO

Multidrug resistance is a highly conserved phenomenon among all living organisms and a major veritable public health problem worldwide. Repetitive uses of antibiotics lead to antimicrobial drug resistance. Here, 19,20-epoxycytochalasin Q (ECQ) was isolated from endophytic fungus Xylaria sp. BCC 1067 and, its chemical structure was determined via chromatographic and spectral methods. ECQ displayed an antifungal activity with low MIC50 of 410 and 55 mg/l in the model yeast Saccharomyces cerevisiae wild-type and ScΔpdr5 strains, respectively. ECQ was a new inducer and potential substrate of key multi-drug efflux pumps S. cerevisiae ScPdr5 and Candida albicans CaCdr1. ECQ targeted actin filament, disrupting actin dynamics of yeast cells. ECQ also sensitized the ScΔsrv2 mutant, lacking suppressor of RasVal19. Overexpression of ScPDR5 or CaCDR1 genes prevented aggregation of actin and alleviated antifungal effect of ECQ. Additionally, ECQ induced high accumulation of reactive oxygen species, caused plasma membrane leakage and decreased yeast cell survival. Importantly, a discovery of ECQ implied a cellular connection between multi-drug resistance and actin stability, an important determinant of transporter mediated-drug resistance mechanism. Combination of ECQ and antifungal azoles displayed promising drug synergy against S. cerevisiae strains expressing multi-drug transporters, thereby providing potential solution for antifungal therapy and chemotherapeutic application.


Assuntos
Actinas/metabolismo , Antifúngicos/farmacologia , Azóis/farmacologia , Candida albicans/efeitos dos fármacos , Citocalasinas/farmacologia , Espécies Reativas de Oxigênio/metabolismo , Saccharomyces cerevisiae/efeitos dos fármacos , Xylariales/química , Transportadores de Cassetes de Ligação de ATP/genética , Transportadores de Cassetes de Ligação de ATP/metabolismo , Actinas/química , Antifúngicos/química , Antifúngicos/metabolismo , Candida albicans/genética , Candida albicans/metabolismo , Citocalasinas/metabolismo , Farmacorresistência Fúngica , Sinergismo Farmacológico , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , Xylariales/metabolismo
12.
J Antibiot (Tokyo) ; 74(3): 215-218, 2021 03.
Artigo em Inglês | MEDLINE | ID: mdl-33173167

RESUMO

Two new cyclopentenone derivatives, daldispones A (1) and B (2) were isolated from the fungus Daldinia sp. CPCC 400770. Their structures and absolute configurations were elucidated by extensive spectroscopic analyses and calculated electronic circular dichroism (ECD). Compounds 1 and 2 exhibited significant anti-influenza A virus activities with IC50 values of 16.0 and 7.4 µM, respectively. Compound 2 showed moderate antibacterial activities against Staphylococcus aureus, Enterococcus faecalis and Bacillus cereus.


Assuntos
Antibacterianos/farmacologia , Antivirais/farmacologia , Ciclopentanos/farmacologia , Xylariales/metabolismo , Antibacterianos/química , Antibacterianos/isolamento & purificação , Antivirais/química , Antivirais/isolamento & purificação , Dicroísmo Circular , Ciclopentanos/química , Ciclopentanos/isolamento & purificação , Concentração Inibidora 50 , Análise Espectral
13.
Nat Prod Res ; 35(12): 2010-2019, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31418292

RESUMO

The ongoing search for anti-cancer agents from microorganisms led to the isolation of four new compounds including 6-ethyl-8-hydroxy-4H-chromen-4-one (1), 6-ethyl-7,8-dihydroxy-4H-chromen-4-one (2), (3S)-3,4-dihydro-8-hydroxy-7-methoxy-3-methylisocoumarin (3) and (3S)-3,4-dihydro-5,7,8-trihydroxy-3-methylisocoumarin (4), together with eleven known compounds (5-15) from Xylaria sp. SWUF09-62 fungus. The chemical structures were deduced from IR, 1D and 2D NMR, and MS data. The absolute configurations of 3 and 4 were determined by ECD experiment. Compounds 2 and 4 indicated possible chemo-prevention and chemo-therapeutic properties, exhibited anti-inflammatory properties by reducing nitric oxide production in LPS-stimulated RAW264.7 cells (IC50 = 1.57 ± 0.25 and 3.02 ± 0.27 µg/mL) and cytotoxicity against HT29 cells (IC50 = 16.46 ± 0.48 and 97.78 ± 7.14 µg/mL).


Assuntos
Anti-Inflamatórios/farmacologia , Antineoplásicos/farmacologia , Produtos Biológicos/farmacologia , Xylariales/química , Animais , Anti-Inflamatórios/química , Antineoplásicos/química , Produtos Biológicos/química , Avaliação Pré-Clínica de Medicamentos , Células HCT116 , Células HT29 , Humanos , Lipopolissacarídeos/toxicidade , Espectroscopia de Ressonância Magnética , Camundongos , Estrutura Molecular , Óxido Nítrico/metabolismo , Células RAW 264.7
14.
Environ Microbiol ; 23(4): 2086-2101, 2021 04.
Artigo em Inglês | MEDLINE | ID: mdl-33314481

RESUMO

Pseudomonas chlororaphis PCL1606 (PcPCL1606) displays plant-colonizing features and exhibits antagonistic traits against soil-borne phytopathogenic fungi. Biofilm formation could be relevant for the PcPCL1606 lifestyle, and in this study the role of some putative extracellular matrix components (EMC; Fap-like fibre, alginate and Psl-like polysaccharides) in the biofilm architecture and biocontrol activity of this bacterium were determined. EMC such as the Fap-like fibre and alginate polysaccharide play secondary roles in biofilm formation in PcPCL1606, because they are not fundamental to its biofilm architecture in flow cell chamber, but synergistically they have shown to favour bacterial competition during biofilm formation. Conversely, studies on Psl-like polysaccharide have revealed that it may contain mannose, and that it is strongly involved in the PcPCL1606 biofilm architecture and niche competition. Furthermore, the Fap-like fibre and Psl-like exopolysaccharide play roles in early surface attachment and contribute to biocontrol activity against the white root rot disease caused by Rosellinia necatrix in avocado plants. These results constitute the first report regarding the study of the extracellular matrix of the PcPCL1606 strain and highlight the importance of a putative Fap-like fibre and Psl-like exopolysaccharide produced by PcPCL1606 in the biofilm formation process and interactions with the host plant root.


Assuntos
Pseudomonas chlororaphis , Xylariales , Ascomicetos , Biofilmes , Matriz Extracelular , Polissacarídeos Bacterianos , Pseudomonas aeruginosa
15.
Phytochemistry ; 182: 112613, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33316595

RESUMO

Seven undescribed isopimarane diterpene glycosides hypoxylonoids A-G, along with five known analogues were obtained from the fungus Xylaria hypoxylon. The structures and absolute configurations of hypoxylonoids A-G were confirmed by extensive spectroscopic and single-crystal X-ray diffraction analyses. Among these compounds, the γ-lactone moiety formed between C-19 and C-6 of hypoxylonoid A; the 1,2-methyl shift of Me-18 of hypoxylonoids B and E; and the decarboxylation of C-19 of hypoxylonoid E, make them outstanding from the isopimarane family. Single crystal X-ray diffraction analyses of hypoxylonoids A, C, F, and 15-hydroxy-16-α-D-mannopyranosyloxyisopimar-7-en-19-oic acid was performed to determine their absolute structural configuration.


Assuntos
Glicosídeos , Xylariales , Abietanos , Ascomicetos , Diterpenos , Estrutura Molecular
16.
Plant Dis ; 104(12): 3143-3150, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-33136520

RESUMO

Ambrosia beetles in the subtribe Hyorrhynchini are one example of an entire ambrosia beetle lineage whose fungi have never been studied. Here, we identify one dominant fungus associated with a widespread Asian hyorrhynchine beetle Sueus niisimai. This fungus was consistently isolated from beetle galleries from multiple collections. Phylogenetic analyses of combined ITS rDNA and ß-tubulin sequences identified the primary fungal symbiont as Diatrypella japonica Higuchi, Nikaido & Hattori (Diatrypaceae, Xylariales, Sordariomycetes), which was recently described as a pathogen of sycamore (Platanus spp.) in Japan. To assess the invasion potential of this beetle-fungus interaction into the U.S., we have investigated the pathogenicity of two D. japonica strains on four species of healthy landscape trees native to the southeastern United States. Only Shumard oak (Quercus shumardii) responded with lesions significantly greater than the control inoculations, but there was no observable dieback or tree mortality. Although disease symptoms were not as prominent as in previous studies of the same fungus in Japan, routine reisolation from the inoculation point suggests that this species is capable of colonizing healthy sapwood of several tree species. Our study shows that the geographical area of its distribution is broader in Asia and potentially includes many hosts of its polyphagous vector. We conclude that the Sueus-Diatrypella symbiosis has high invasion potential but low damage potential, at least on young trees during the growing season.


Assuntos
Besouros , Doença , Gorgulhos , Xylariales , Ambrosia , Animais , Japão , Filogenia , Doenças das Plantas , Sudeste dos Estados Unidos
17.
Phytochemistry ; 179: 112505, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32919290

RESUMO

Four undescribed pyrone derivatives, pestalopyrones A-D, containing unusual tricyclic 5/6/6 polycyclic skeletons, were isolated from the ethyl acetate extract of the endophytic fungus Pestalotiopsis neglecta S3 derived from the fresh stems of Rubia podantha Diels (Rubiaceae). Their planar structures were elucidated mainly by NMR and HRESIMS. Pestalopyrones A-D contained six contiguous chiral carbons, and the relative configurations of C-4, C-5, and C-8 in tricyclic 5/6/6 polycyclic skeletons were determined by ROESY spectra. For pestalopyrone B, the absolute configuration of C-16 was determined by the Mosher's method. All isolated compounds were tested for their cytotoxicity against cancer cell lines, antibacterial activity, and inhibitory effect on the lipopolysaccharide (LPS)-induced nitric oxide (NO) production, and the results showed that pestalopyrone A inhibited LPS-induced NO production with an IC50 value of 35.8 µM.


Assuntos
Pironas , Xylariales , Estrutura Molecular , Pironas/farmacologia
18.
Curr Microbiol ; 77(11): 3603-3611, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32864708

RESUMO

In the present work, ethyl acetate extracts, consisting of non-volatile compounds, from the culture of endophytic fungi isolated from coffee plants, Induratia coffeana and Induratia yucatanensis, were prospected in enzyme modulation tests that act in human hemostasis. Dry extracts of the fungi were diluted in dimethyl sulfoxide p.a. 99.9% (DMSO), and then tested. Bothrops atrox venom was used as an enzyme source and tool to induce the activities. Prior to the evaluation of the activities, incubations of the extracts with the venom were performed in the proportions 1: 0.01, 1: 0.25, 1: 0.5, and 1: 1 (venom: extract; mass: mass). The extracts of all fungi promoted a significant increase in the clotting time induced by the venom, which was even longer when the extracts were previously incubated with the citrated plasma. The activity of phospholipases A2 did not significantly change when evaluated in the presence of fungal extracts. However, the evaluated extracts inhibited proteases by 73% and 30% in the thrombolytic and caseinolytic tests, respectively. In addition, the extracts did not induce cytotoxicity on human erythrocytes when evaluated in the absence of the venom. Thus, it is possible to suggest the presence of specific interactions between molecules present in extracts of Induratia spp. and venom proteases, highlighting non-volatile metabolites as promising sources of compounds of medical and scientific interest.


Assuntos
Extratos Vegetais , Xylariales , Humanos , Fosfolipases A2 , Extratos Vegetais/farmacologia
19.
Acta amaz ; 50(3): 273-277, jul. - set. 2020.
Artigo em Inglês | LILACS | ID: biblio-1118861

RESUMO

Three species of the Ascomycetes genus Camillea were recorded in a fragment of Amazon rainforest in the region of Santarém, Pará state, Brazil. The occurrence of C. leprieurii, C. cyclops and C. bilabiata expand the range of distribution of these species in the state. Camillea leprieurii has previous records in the regions of Marabá, Oriximiná, Itaituba and Novo Progresso, while C. cyclops had been recorded in the west of the state. This is the first record of C. bilabiata for Pará. We provide a morphological description of the specimens and an identification key for Camillea species found in Pará. (AU)


Assuntos
Ascomicetos , Xylariales , Fungos , Ecossistema Amazônico
20.
Pestic Biochem Physiol ; 169: 104670, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32828376

RESUMO

Hypoxylon species are distributed worldwide and have been isolated from different habitats. The endophyte Hypoxylon anthochroum strain Gseg1 was isolated from healthy leaves of Gliricidia sepium. A chemical study of the culture medium and mycelium organic extracts of the endophytic fungus H. anthochroum Gseg1 led to the isolation of three known isobenzofuranones, 7-hydroxy-4,6-dimethyl-3H-isobenzofuran-1-one, 1, 7-methoxy-4,6-dimethyl-3H-isobenzofuran-1-one, 2, 6-formyl-4-methyl-7-methoxy-3H-isobenzofuran-1-one, 3, and one compound was isolated for the first time as a natural product, 7-methoxy-4-methyl-3H-isobenzofuran-1-one, 4. In addition, the chemical synthesis of 1 and 2, and a derivative, 7-methoxy-6-methyl-3H-isobenzofuran-1-one, 5, was performed. The isobenzofuranones showed antifungal and antioomycete activities. Compounds 1-5 inhibited the growth of Fusarium oxysporum, Alternaria alternata, Pythium aphanidermatum, and Phytophthora capsici, in addition, 1, 2 and 5 interrupted the respiration and caused electrolyte leakage due to cell membrane damage. Compound 2 was the most active, inhibiting the growth of the four microorganisms, affecting the respiration and increasing the relative conductivity due to electrolyte leakage. Compounds 1-4 also induce morphological changes in the plant pathogens' mycelia and hyphae. These compounds could be useful for the control of plant pathogenic fungi and oomycetes of agricultural relevance.


Assuntos
Phytophthora , Pythium , Xylariales , Antifúngicos , Endófitos
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