Naphthoquinones isolated from Quambalaria cyanescens (quambalarines) are natural pigments possessing significant cytotoxic and antimicrobial properties. Determining the structure of naphthoquinone compounds is important for the understanding of their biological activities and the informed synthesis of related analogues. Identifying quambalarines is challenging, because they contain a hydroxylated naphthoquinone scaffold and have limited solubility. Here, we report a detailed structural study of quambalarine derivatives, which form strong intramolecular hydrogen bonds (IMHBs) that enable the formation of several tautomers; these tautomers may complicate structural investigation due to their fast interconversion. To investigate tautomeric equilibria and identify new quambalarines, we complemented the experimental NMR spectroscopy data with density functional theory (DFT) calculations.
- MeSH
- antiinfekční látky chemie izolace a purifikace farmakologie MeSH
- Basidiomycota chemie MeSH
- magnetická rezonanční spektroskopie MeSH
- magnetická rezonanční tomografie MeSH
- molekulární struktura MeSH
- naftochinony chemie izolace a purifikace farmakologie MeSH
- protinádorové látky chemie izolace a purifikace farmakologie MeSH
- vodíková vazba MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Ergot, fungal genus Claviceps, are worldwide distributed grass pathogens known for their production of toxic ergot alkaloids (EAs) and the great agricultural impact they have on both cereal crop and farm animal production. EAs are traditionally considered as the only factor responsible for ergot toxicity. Using broad sampling covering 13 ergot species infecting wild or agricultural grasses (including cereals) across Europe, USA, New Zealand, and South Africa we showed that the content of ergochrome pigments were comparable to the content of EAs in sclerotia. While secalonic acids A-C (SAs), the main ergot ergochromes (ECs), are well known toxins, our study is the first to address the question about their contribution to overall ergot toxicity. Based on our and published data, the importance of SAs in acute intoxication seems to be negligible, but the effect of chronic exposure needs to be evaluated. Nevertheless, they have biological activities at doses corresponding to quantities found in natural conditions. Our study highlights the need for a re-evaluation of ergot toxicity mechanisms and further studies of SAs' impact on livestock production and food safety.
- MeSH
- apoptóza účinky léků MeSH
- Claviceps chemie MeSH
- HeLa buňky MeSH
- Jurkat buňky MeSH
- lidé MeSH
- mitochondrie účinky léků MeSH
- mykotoxiny analýza farmakologie toxicita MeSH
- námelové alkaloidy analýza toxicita MeSH
- viabilita buněk účinky léků MeSH
- xantheny analýza toxicita MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
The ergot, genus Claviceps, comprises approximately 60 species of specialised ovarial grass parasites famous for the production of food toxins and pharmaceutics. Although the ergot has been known for centuries, its evolution have not been resolved yet. Our approach combining multilocus phylogeny, molecular dating and the study of ecological, morphological and metabolic features shows that Claviceps originated in South America in the Palaeocene on a common ancestor of BEP (subfamilies Bambusoideae, Ehrhartoideae, Pooideae) and PACMAD (subfamilies Panicoideae, Aristidoideae, Chloridoideae, Micrairoideae, Arundinoideae, Danthonioideae) grasses. Four clades described here as sections diverged during the Paleocene and Eocene. Since Claviceps are parasitic fungi with a close relationship with their host plants, their evolution is influenced by interactions with the new hosts, either by the spread to a new continent or the radiation of the host plants. Three of the sections possess very narrow host ranges and biogeographical distributions and have relatively low toxicity. On the contrary, the section Claviceps, comprising the rye ergot, C. purpurea, is unique in all aspects. Fungi in this section of North American origin have spread all over the world and infect grasses in all subfamilies as well as sedges, and it is the only section synthesising toxic ergopeptines and secalonic acids. The evolutionary success of the Claviceps section members can be explained by high toxin presence, serving as feeding deterrents and playing a role in their protective mutualism with host plants. Closely related taxa Neoclaviceps monostipa and Cepsiclava phalaridis were combined into the genus Aciculosporium.
- MeSH
- Bayesova věta MeSH
- časové faktory MeSH
- Claviceps klasifikace MeSH
- fylogeneze * MeSH
- genetické lokusy MeSH
- hostitelská specificita MeSH
- námelové alkaloidy biosyntéza chemie MeSH
- sekundární metabolismus MeSH
- zeměpis MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Geografické názvy
- Jižní Amerika MeSH
Abnormalities in cancer metabolism represent potential targets for cancer therapy. We have recently identified a natural compound Quambalarine B (QB), which inhibits proliferation of several leukemic cell lines followed by cell death. We have predicted ubiquinone binding sites of mitochondrial respiratory complexes as potential molecular targets of QB in leukemia cells. Hence, we tracked the effect of QB on leukemia metabolism by applying several omics and biochemical techniques. We have confirmed the inhibition of respiratory complexes by QB and found an increase in the intracellular AMP levels together with respiratory substrates. Inhibition of mitochondrial respiration by QB triggered reprogramming of leukemic cell metabolism involving disproportions in glycolytic flux, inhibition of proteins O-glycosylation, stimulation of glycine synthesis pathway, and pyruvate kinase activity, followed by an increase in pyruvate and a decrease in lactate levels. Inhibition of mitochondrial complex I by QB suppressed folate metabolism as determined by a decrease in formate production. We have also observed an increase in cellular levels of several amino acids except for aspartate, indicating the dependence of Jurkat (T-ALL) cells on aspartate synthesis. These results indicate blockade of mitochondrial complex I and II activity by QB and reduction in aspartate and folate metabolism as therapeutic targets in T-ALL cells. Anti-cancer activity of QB was also confirmed during in vivo studies, suggesting the therapeutic potential of this natural compound.
- Publikační typ
- časopisecké články MeSH
Pathogenic and non-pathogenic related microorganisms differ in secondary metabolite production. Here we show that riboflavin overproduction by a fungal pathogen and its hyperaccumulation in affected host tissue exacerbates a skin infection to necrosis. In white-nose syndrome (WNS) skin lesions caused by Pseudogymnoascus destructans, maximum riboflavin concentrations reached up to 815 μg ml(-1), indicating bioaccumulation and lack of excretion. We found that high riboflavin concentrations are cytotoxic under conditions specific for hibernation, affect bats' primary fibroblasts and induce cell detachment, loss of mitochondrial membrane potential, polymerization of cortical actin, and cell necrosis. Our results explain molecular pathology of WNS, where a skin infection becomes fatal. Hyperaccumulation of vitamin B2 coupled with reduced metabolism and low tissue oxygen saturation during hibernation prevents removal of excess riboflavin in infected bats. Upon reperfusion, oxygen reacts with riboflavin resulting in dramatic pathology after arousal. While multiple molecules enable invasive infection, riboflavin-associated extensive necrosis likely contributes to pathophysiology and altered arousal pattern in infected bats. Bioaccumulation of a vitamin under natural infection represents a novel condition in a complex host-pathogen interplay.
- MeSH
- Ascomycota klasifikace genetika patogenita MeSH
- buněčná adheze MeSH
- Chiroptera mikrobiologie MeSH
- dermatomykózy mikrobiologie MeSH
- elektronová mikroskopie MeSH
- faktory virulence metabolismus MeSH
- fibroblasty cytologie metabolismus mikrobiologie MeSH
- fylogeneze MeSH
- interakce hostitele a patogenu MeSH
- křídla zvířecí cytologie mikrobiologie ultrastruktura MeSH
- kultivované buňky MeSH
- membránový potenciál mitochondrií MeSH
- riboflavin metabolismus MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Quambalarine B (QB) is a secondary metabolite produced by the basidiomycete Quambalaria cyanescens with potential anticancer activity. Here we report that QB at low micromolar concentration inhibits proliferation of several model leukemic cell lines (Jurkat, NALM6, and REH), whereas higher concentrations induce cell death. By contrast, the effect of QB on primary leukocytes (peripheral blood mononuclear cells) is significantly milder with lower toxicity and cytostatic activity. Moreover, QB inhibited expression of the C-MYC oncoprotein and mRNA expression of its target genes, LDHA, PKM2, and GLS. Finally, QB blocked the phosphorylation of P70S6K, a downstream effector kinase in mTOR signaling that regulates translation of C-MYC. This observation could explain the molecular mechanism behind the antiproliferative and cytotoxic effects of QB on leukemic cells. Altogether, our results establish QB as a promising molecule in anticancer treatment.
- MeSH
- Basidiomycota chemie MeSH
- fosforylace MeSH
- Jurkat buňky účinky léků MeSH
- kinasy ribozomálního proteinu S6, 70-kDa MeSH
- leukocyty mononukleární účinky léků MeSH
- lidé MeSH
- molekulární struktura MeSH
- naftochinony krev chemická syntéza chemie izolace a purifikace farmakologie MeSH
- proliferace buněk účinky léků MeSH
- protinádorové látky krev chemie izolace a purifikace farmakologie MeSH
- screeningové testy protinádorových léčiv MeSH
- signální transdukce fyziologie MeSH
- TOR serin-threoninkinasy MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
Results of a survey and study of the Claviceps purpurea group of species in South Africa are being presented and five new species are described. Morphological descriptions are based on the anamorphs and four nuclear genetic loci. Claviceps fimbristylidis sp. nov. on Fimbristylis complanata was discovered wide-spread across five provinces of the country associated with water and represents the fourth Claviceps species recorded from the Cyperaceae. Claviceps monticola sp. nov. is described from Brachypodium flexum growing in mountain forests in Mpumalanga Province, as well as the northern Drakensberg southwards into the Eastern Cape Province. Claviceps pazoutovae sp. nov. is recorded from Stipa dregeana var. dregeana and Ehrharta erecta var. erecta, also associated with these mountain ranges. Claviceps macroura sp. nov. is recorded from Cenchrus macrourus from the Eastern Cape and Claviceps capensis sp. nov. from Ehrharta villosa var. villosa is recorded from the Western Cape Province. Claviceps cyperi, only recorded from South Africa is included in the study. Ergot alkaloid profiles of all species are provided and showed similarity to C. purpurea. Only C. cyperi and in lesser degree C. capensis, C. macroura, and C. pazoutovae produced ergot alkaloids in clinically significant amounts. Several reported species infect invasive grass species, native to South Africa, and thus represent potentially invasive species.
- MeSH
- Claviceps chemie klasifikace genetika izolace a purifikace MeSH
- DNA fungální chemie genetika MeSH
- elongační faktor 1 genetika MeSH
- fylogeneze MeSH
- lesy MeSH
- MCM komplex, komponenta 7 genetika MeSH
- mikrobiologie životního prostředí * MeSH
- námelové alkaloidy analýza MeSH
- ribozomální DNA chemie genetika MeSH
- sekvenční analýza DNA MeSH
- shluková analýza MeSH
- tubulin genetika MeSH
- voda MeSH
- vysokoúčinná kapalinová chromatografie MeSH
- Publikační typ
- časopisecké články MeSH
- Geografické názvy
- Jihoafrická republika MeSH
A strain of Biatriospora sp. CCF 4378 was tested for the production of secondary metabolites under submerged fermentation conditions. Eleven compounds were isolated from the culture broth, and the structures of these compounds were determined using HRMS, NMR and X-ray analysis. In addition to six known naphthoquinone derivatives, i.e. ascomycone A, ascomycone B, 6-deoxyfusarubine, 6-deoxyanhydrofusarubine, herbarine and balticol A, one derivative of 2-azaanthraquinone, 6-deoxybostrycoidine, was also identified. Four new natural pyranonaphthoquinones were found, and these natural products were pleorubrin A, pleorubrin B, pleorubrin C and pleorubrin D. The toxicity on human cell lines of the crude naphthoquinone fraction and pure 6-deoxybostrycoidin, ascomycone B, pleorubrin B and 6-deoxyfusarubin was tested. Ascomycone B and 6-deoxyfusarubin elicited rapid cytotoxicity at micromolar concentrations.
- MeSH
- Ascomycota klasifikace genetika izolace a purifikace metabolismus MeSH
- buněčné linie MeSH
- endofyty klasifikace genetika izolace a purifikace metabolismus MeSH
- lidé MeSH
- molekulární struktura MeSH
- naftochinony chemie metabolismus farmakologie MeSH
- Ulmus mikrobiologie MeSH
- viabilita buněk účinky léků MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
A new, efficient, and general semisynthesis of hydnocarpin-type flavonolignans was developed and optimized, enabling gram-scale production of hydnocarpin D (2). Moreover, the syntheses of optically pure hydnocarpin isomers [(10R,11R)-hydnocarpin (1a), (10R,11R)-hydnocarpin D (2a), and (10S,11S)-hydnocarpin D (2b)], as well as the synthesis of isohydnocarpin (8), were achieved for the first time utilizing this new method. The synthesis is based on the two-step transformation of the readily available flavonolignans from milk thistle (Silybum marianum), accessible by isolation from the commercial extract silymarin. The first step relies on the regioselective formylation of the C-3 hydroxy group of the dihydroflavonol-type precursor using the Vilsmeier-Haack reagent, followed by formic acid elimination by triethylamine in the second step. The synthesized compounds were effective inhibitors of Staphylococcus aureus biofilm formation, with (10S,11S)-hydnocarpin D (2b) being the most potent inhibitor. Furthermore, the effect of glucose on biofilm formation was tested, and glucose decreased the biofilm inhibitory activity of 2b. Moreover, 2b increased the susceptibility of Staph. aureus to enrofloxacin.
- MeSH
- antioxidancia MeSH
- biofilmy účinky léků MeSH
- flavonolignany chemie izolace a purifikace farmakologie MeSH
- molekulární struktura MeSH
- nukleární magnetická rezonance biomolekulární MeSH
- ostropestřec mariánský chemie MeSH
- silymarin chemie MeSH
- Staphylococcus aureus účinky léků MeSH
- vysokoúčinná kapalinová chromatografie MeSH
- vztahy mezi strukturou a aktivitou MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Four strains of the fungus Quambalaria cyanescens (Basidiomycota: Microstromatales), were used for the determination of secondary metabolites production and their antimicrobial and biological activities. A new naphthoquinone named quambalarine A, (S)-(+)-3-(5-ethyl-tetrahydrofuran-2-yliden)-5,7,8-trihydroxy-2-oxo-1,4-naphthoquinone (1), together with two known naphthoquinones, 3-hexanoyl-2,5,7,8-tetrahydroxy-1,4-naphthoquinone (named here as quambalarine B, 2) and mompain, 2,5,7,8-tetrahydroxy-1,4-naphthoquinone (3) were isolated. Their structures were determined by single-crystal X-ray diffraction crystallography, NMR and MS spectrometry. Quambalarine A (1) had a broad antifungal and antibacterial activity and is able inhibit growth of human pathogenic fungus Aspergillus fumigatus and fungi co-occurring with Q. cyanescens in bark beetle galleries including insect pathogenic species Beauveria bassiana. Quambalarine B (2) was active against several fungi and mompain mainly against bacteria. The biological activity against human-derived cell lines was selective towards mitochondria (2 and 3); after long-term incubation with 2, mitochondria were undetectable using a mitochondrial probe. A similar effect on mitochondria was observed also for environmental competitors of Q. cyanescens from the genus Geosmithia.
- MeSH
- antiinfekční látky chemie izolace a purifikace metabolismus farmakologie MeSH
- Basidiomycota metabolismus MeSH
- biologické přípravky chemie izolace a purifikace metabolismus farmakologie MeSH
- buněčné linie MeSH
- fermentace * MeSH
- lidé MeSH
- mikrobiální testy citlivosti MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
