Epicoccum Nigrum Research Articles

The Common Deathwatch Beetle Xestobium rufovillosum (DeGeer, 1774) as a Pest for Paper in Books

AbstractA small repository in a cathedral in Poland, storing severely damaged books, was investigated with regard to insects and fungi. Entomological and microbiological surveys were performed to estimate the extent of the infestation and the microbial deterioration of the books. Most of the books were attacked by insects although to varying degrees. They were damaged by tunnels bored by the larvae and filled with larval faeces. Some living larvae and many dead adult beetles were found in the books or in the frass. The larvae and most of the beetles were identified as the common deathwatch beetle Xestobium rufovillosum (DeGeer, 1774). The development of Xestobium rufovillosum in books is an unusual case and has rarely been mentioned in the literature. Several books in the repository were also covered by microfungi, especially by Chaetomium murorum, Ch. elatum, Myxotrichum chartarum, Stachybotrys atra and Epicoccum nigrum. The temperature in the repository varied, depending on the season of the year (2.6 °C – 26.2 °C), while the relative humidity was high (constantly above 65 %). The concentration of the fungal bioaerosol was very high (4,120 cfu/m3). The article includes a list of recommendations pertaining to the elimination of the microorganisms and insects.

Investigating hyperparasites as potential biological control agents of rust pathogens on cereal crops

Rust pathogens cause damage to cereal crops around the world, leading to reduced yield and profit. Current methods of rust control include fungicides, resistant cultivars, and preventative agronomic practices. Some hyperparasites are antagonists of plant pathogens and may provide a potential method of biocontrol against increasingly virulent strains of rust. Very little is known about the mechanism of inhibition of rust growth by hyperparasites, however, isolation of new strains and subsequent characterisation may reveal new treatment strategies for the control of rust. Here we report the isolation of six new fungal hyperparasites and their effects on the development of three Puccinia rust pathogens were examined in vitro, to determine the potential of each as biocontrol agents of rust. Cut-leaf sections of rust-susceptible wheat, barley and oat cultivars were treated with fungal hyperparasite conidia prior to infection with the rust species; Puccinia triticina, P. hordei, and P. coronata f. sp. avenae, respectively. Inhibition of rust spore germination tests were also performed on water agar plates co-inoculated with the isolates. In leaf sections, rust pustule number was significantly (P < 0.01) lower for all six isolates tested: Penicillium brevicompactum, Clonostachys rosea, Simpicillium aogashimaense, Neoascochyta sp., Lecanicillium psalliotae and Epicoccum nigrum. The results of these experiments suggest that the mechanisms underlying the reduction in pustule number could include one or more of the processes of direct parasitism, antagonism by antibiosis, competition, and/or induction of host plant resistance.

Cytotoxic Thiodiketopiperazine Derivatives from the Deep Sea-Derived Fungus Epicoccum nigrum SD-388.

Four new thiodiketopiperazine alkaloids, namely, 5’-hydroxy-6’-ene-epicoccin G (1), 7-methoxy-7’-hydroxyepicoccin G (2), 8’-acetoxyepicoccin D (3), and 7’-demethoxyrostratin C (4), as well as a pair of new enantiomeric diketopiperazines, (±)-5-hydroxydiphenylalazine A (5), along with five known analogues (6–10), were isolated and identified from the culture extract of Epicoccum nigrum SD-388, a fungus obtained from deep-sea sediments (−4500 m). Their structures were established on the basis of detailed interpretation of the NMR spectroscopic and mass spectrometric data. X-ray crystallographic analysis confirmed the structures and established the absolute configurations of compounds 1–3, while the absolute configurations for compounds 4 and 5 were determined by ECD calculations. Compounds 4 and 10 showed potent activity against Huh7.5 liver tumor cells, which were comparable to that of the positive control, sorafenib, and the disulfide bridge at C-2/C-2’ is likely essential for the activity.

Indoor Microbiome: Quantification of Exposure and Association with Geographical Location, Meteorological Factors, and Land Use in France.

The indoor microbial community is a mixture of microorganisms resulting from outdoor ecosystems that seed the built environment. However, the biogeography of the indoor microbial community is still inadequately studied. Dust from more than 3000 dwellings across France was analyzed by qPCR using 17 targets: 10 molds, 3 bacteria groups, and 4 mites. Thus, the first spatial description of the main indoor microbial allergens on the French territory, in relation with biogeographical factors influencing the distribution of microorganisms, was realized in this study. Ten microorganisms out of 17 exhibited increasing abundance profiles across the country: Five microorganisms (Dermatophagoïdes pteronyssinus, Dermatophagoïdes spp., Streptomyces spp., Cladosporium sphaerospermum, Epicoccum nigrum) from northeast to southwest, two (Cryptococcus spp., Alternaria alternata) from northwest to southeast, Mycobacteria from east to west, Aspergillus fumigatus from south to north, and Penicillium chrysogenum from south to northeast. These geographical patterns were partly linked to climate and land cover. Multivariate analysis showed that composition of communities seemed to depend on landscapes, with species related to closed and rather cold and humid landscapes (forests, located in the northeast) and others to more open, hot, and dry landscapes (herbaceous and coastal regions, located in the west). This study highlights the importance of geographical location and outdoor factors that shape communities. In order to study the effect of microorganisms on human health (allergic diseases in particular), it is important to identify biogeographic factors that structure microbial communities on large spatial scales and to quantify the exposure with quantitative tools, such as the multi-qPCR approach.

Amphiepicoccins A-J: Epipolythiodioxopiperazines from the Fish-Gill-Derived Fungus Epicoccum nigrum HDN17-88.

Ten new epipolythiodioxopiperazines (ETPs), namely, amphiepicoccins A-J (1-10), were isolated from the fish-gill-derived fungus Epicoccum nigrum HDN17-88. Their structures were deduced from extensive spectroscopic data and electronic circular dichroism (ECD) calculations. Amphiepicoccin A (1) which contains an aromatic indole motif is unprecedented among the epicoccin type of ETPs. Compounds 1, 3, and 6 displayed anti-HSV-2 activities, with IC50 values of 70, 64, and 29 μM, respectively (acyclovir as positive control with an IC50 value of 31 μM), while 5 and 6 also revealed inhibitory activity against Bacillus subtilis with minimum inhibitory concentration (MIC) values of 13 and 25 μM, respectively.

Spray Drying of Coloring Extracts Produced by Fungi Isolated from Brazilian Caves

Abstract Pigments produced by submerged fermentation of three filamentous fungi isolated from Brazilian caves, namely Aspergillus keveii, Penicillium flavigenum, and Epicoccum nigrum, were submitted to spray drying in presence of the adjuvants maltodextrin, modified starch or gum arabic. Yellow fine powders with low moisture content and water activity, and high color retention (> 70%) were successfully generated with a high product recovery ratio (> 50%), independently of the adjuvant used. The dried products have enhanced stability and potential to might be used as a natural colorant in food and pharmaceutical applications.

Fused multicyclic polyketides with a two-spiro-carbon skeleton from mangrove-derived endophytic fungus Epicoccum nigrum SCNU-F0002.

A pair of uncommon fused multicyclic polyketides with a two- spiro-carbon skeleton, (±)-isoepicolactone, (±)-1, and one new isobenzofuranone monomer (4), together with four other known biosynthetically related compounds were isolated from the fermentation of an endophytic fungus, Epicoccum nigrum SCNU-F0002, which was isolated from the fresh fruit of the mangrove plant Acanthus ilicifolius L. Comprehensive spectroscopic analysis, X-ray crystallography, together with calculated ECD, were employed to define the structures. The antibacterial and COX-2 inhibitory activities of the compounds (1–6) were evaluated. A possible biogenetic pathway of (±)-isoepicolactone was confirmed.

Biotransformation of Host Plant Flavonoids by the Fungal Endophyte Epicoccum nigrum

AbstractFermentation of the fungus Epicoccum nigrum isolated from leaves of Salix sp. on green lentil solid medium yielded the flavonol kaempferol (3) as well as two kaempferol O‐diglycosides (1 and 2) including the new compound 1. The fungal flavonoids bear strong structural similarities to kaempferol derivatives such as kaempferol O‐glycoside (4) being present in green lentils. Furthermore, feeding experiments were conducted by adding flavonoids (kaempferol and rutin) as precursors to solid rice media followed by HPLC and LC‐MS analyses. Fermentation of the fungus on flavonoid free solid rice medium afforded flavonoid free extracts indicating that the fungal flavonoids originate through hydrolytic cleavage of kaempferol glycosides such as 4 followed by glycosylation and acetylation. This study suggests that E. nigrum is capable of biotransformation reactions of plant derived flavonoids whereas de novo biosynthesis of flavonoids is less likely.

A novel source of the cardiac glycoside digoxin from the endophytic fungus Epicoccum nigrum: isolation, characterization, production enhancement by gamma irradiation mutagenesis and anticancer activity evaluation.

Different endophytic fungi were isolated and screened for their digoxin-producing ability. Strain improvement and different culture conditions were studied for more effective production of digoxin. Among the isolated fungi, an isolate produced digoxin in a concentration of 2·07mgl-1 . The digoxin-producing fungal isolate was identified as Epicoccum nigrum Link according to the morphological features and phylogenetic analyses. The potentiality of the fungal strain for production enhancement of digoxin was performed by gamma radiation mutagenesis. Gamma irradiation dose of 1000Gy intensified the digoxin yield by five-fold. Using this dose, a stable mutant strain with improved digoxin productivity was isolated and the stability for digoxin production was followed up across four successive generations. In the effort to increase digoxin magnitude, selection of the proper cultivation medium, addition of some elicitors to the most proper medium and several physical fermentation conditions were tested. Fermentation process carried out in malt extract autolysate medium (pH 6·5) supplemented by methyl jasmonate and inoculated with 2ml of 6-day-old culture and incubated at 25°C for 10days stimulated the highest production of digoxin to attain 50·14mgl-1 . Moreover, cytotoxicity of digoxin separated from the fungal culture was tested against five different cancer cell lines. Based on the MTT assay, digoxin inhibited the proliferation of the five different cancer cell lines and the recorded 50% inhibitory concentration ranged from 10·76 to 35·14μgml-1 . This is the first report on the production and enhancement of digoxin using fungal fermentation as a new and alternate source with high productivity. These findings offer new and alternate sources with excellent biotechnological potential for digoxin production by fungal fermentation. Moreover, digoxin proved to be a promising anticancer agent whose anticancer potential should be assessed in prospective cancer therapy.

Exploring the potential of Epicoccum nigrum for pigment production under variable conditions

Purpose The purpose of this study is to isolate yellow pigment producing fungal strain and to determine the media requirement for growth and secondary metabolite production. Design/methodology/approach Fifteen soil samples were collected and studied for a pigment producing fungal sources. Selection of a fungus was based on pigment produced and further conditions, such as effect of media composition and light wavelength on pigment production and growth parameters were optimised. Findings Out of the isolates analysed, Epicoccum nigrum was selected for further study as this strain has the potential for pigment production. Among all the media evaluated, potato dextrose agar (PDA) was found to be the best media for growth and sporulation, whilst sabouraud dextrose agar (SDA) was only 29 per cent as capable as the best medium. The radial growth rate in case of PDA was 3 ± 0.02 mm/day, while in case of SDA, it was only 1.09 mm/day. Whilst starch as a carbon source was found to increase the radial growth to 5.15 ± 0.02 mm/day, sucrose significantly (p &lt; 0.05) influenced the sporulation (224,000 ± 1,550 spores/ml) of Epicoccum nigrum. Amongst the various nitrogen sources analysed, peptone significantly increased (p &lt; 0.05) the radial growth (6.55 ± 0.02 mm/day) as well as sporulation (220,000 ± 2,100 spores/ml). The observations also indicated that E. nigrum is able to sense and differentiate between light in different wavelength ranges and respond differently in growth and sporulation. The light passing through a red colour sheet resulted in better radial growth (8.5 ± 0.02 mm/day) in comparison to unfiltered light (3 ± 0.02 mm/day). Yellow pigment production in terms of hue values was significantly influenced by the presence of dextrose, peptone and darkness. Research limitations/implications The isolated strain could be studied for variable conditions and stress factors for optimal production of the pigment. Recovery and purification studies could be carried out at pilot and industrial scale. Practical implications The isolation of a strain producing valuable microbial pigment will increase the alternatives of natural food colours and enhance the its commercial applications Originality/value This study identifies Epicoccum nigrum as a potential source of microbial pigment and facilitates its growth and production for possible applications in industrial pigment production.

Isobenzofuranone monomer and dimer derivatives from the mangrove endophytic fungus Epicoccum nigrum SCNU-F0002 possess α-glucosidase inhibitory and antioxidant activity.

Four new isobenzofuranone monomers, (+)-epicoccone C ((+)-1), (-)-epicoccone C ((-)-1), epicoccone D (2), epicoccone E (3) and one new isobenzofuranone dimer, epicolactone A (4), together with four known related dimers were obtained from the fermentation of an endophytic fungus, Epicoccum nigrum SCNU-F0002, which was isolated from the fresh fruit of the mangrove plant Acanthus ilicifolius L. Their structures were elucidated on the basis of spectroscopic methods, single-crystal X-ray diffraction analysis, and electronic circular dichroism calculations. These isolated compounds (1-8) were evaluated for their antioxidant activity and α-glucosidase enzyme inhibitory activity. All of the compounds except 5 exhibited more potent α-glucosidase inhibitory effect than acarbose. Most of the compounds showed superior antioxidant activity with IC50 values ranging from 10.2 to 15.3 μM than positive control, gallic acid and vitamin C.

Fungal community associated with adults of the chestnut gall wasp Dryocosmus kuriphilus after emergence from galls: Taxonomy and functional ecology

The diversity of the fungal community associated with adults of Dryocosmus kuriphilus following emergence was examined using HTS analysis. Ascomycota dominated the fungal core-biome community. The functional guilds of the 90 taxa forming the core-biome were assessed, demonstrating three main groups: saprotrophs, plant pathogens and entomopathogens. Twenty-nine OTUs out of 90 were resolved to species level identifying 26 different fungal species. Among these species, many were cosmopolitan or previously recorded in Europe. Ten taxa were previously recorded on chestnut, including some recognized plant pathogens associated with foliage and green tissues such as Epicoccum nigrum, Gnomoniopsis castanea, Colletotrichum acutatum, Stromatoseptoria castaneicola, Ramularia endophylla. Beauveria bassiana; within the core microbiome, Fusarium larvarum represented the most abundant entomopathogenic species. Some of these species are known to impact directly or indirectly the vitality of the insects in the galls. The chestnut blight pathogen, Cryphonectria parasitica, was never found associated with D. kuriphilus. Based on the present study, an active role for D. kuriphilus as a vector of chestnut fungal endophyte/pathogens cannot be demonstrated but neither ruled out.

Antagonistic Potential of Macrolepiota sp. Against Alternaria Solani as Causal Agent of Early Blight Disease in Tomato Plants

The aim of this study was to identify a Mexican native basidiomycete strain with antagonistic potential against phytopathogenic fungi. The antifungal activity of fifteen isolates against Fusarium oxysporum, Fusarium solani, Colletotrichum truncatum, Colletotrichum coccodes, Colletotrichum sp., Stemphylium solani, Botrytis cinerea, Epicoccum nigrum, Phomopsis sp. and Alternaria solani was studied in vitro using dual culture assay. An isolate of Macrolepiota sp (CS185) exhibited the strongest ability to compete on potato dextrose agar medium (PDA) causing 22.2 up to 46.6% inhibition in seven out of ten pathogens evaluated. The addition of 30% Macrolepiota sp. liquid filtrates (from 7 day-cultures in potato dextrose broth) to PDA plates inhibited 66% of A. solani growth. Application of Macrolepiota sp. CS185 culture fluids to control early blight disease caused in tomato plants by A. solani under greenhouse conditions diminished disease incidence and percent of damage. The length of the stems, the roots and the foliar area increased in the treated plants and, above all, the foliar symptoms decreased by 73%. Sesquiterpene lactones and quinones identified in culture fluids might be responsible for Macrolepiota antifungal activity. This study proves that Macrolepiota sp. CS185 culture filtrates have potential in biocontrol of early blight disease.

Secondary metabolites from Epicoccum nigrum 14one,an endophytic fungus isolated from plant Leptogium masiaticum

Phytochemical investigation of the culture of Epicoccum nigrum,an endolichenic fungus inhabiting Leptogium masiaticum,led to the isolation of 11 compounds. Based on NMR spectroscopy and HRESIMS data,their structures were determined as one alkaloid fusaricide( 1),and seven benzofuran derivatives including epicoccone( 2),4,6-dihydroxy-5-methoxy-7-methyl-1,3-dihydro isobenzofuran( 3),5-methyl-epicoccone B( 4),3,6,7-trihydroxy-5-methoxy-4-methylisobenzo furan-1( 3 H)-one( 5),3-methoxyepicoccone B( 6),2,3,4-trihydroxy-6-( hydroxymethyl)-5-methylbenzyl-alcohol( 7),and isoochracinic acid( 8),together with three epicoccolide analogs epicocconigrones A( 9),epicoccolide B( 10),and epicocconigrones B( 11). Compounds 1,9 and 10 showed potent microorganism inhibitory effects. These results indicated the potential perspective of this endophytic fungus as an eco-friendly biocide.

Two-Photon Absorption and Cell Imaging of Fluorene-Functionalized Epicocconone Analogues.

Epicocconone 1 is a natural chromophore isolated from the fungus Epicoccum nigrum that has shown applications in proteomics and fluorescent microscopy thanks to its unique pro-fluorescence properties. The modification of the skeleton of the natural product by replacing the triene side chain by a fluorenyl scaffold can noticeably increase the fluorophore's absorption coefficient. The synthesis of the analogues of the natural product has been made possible by the use of a palladium-catalyzed carbonylation reaction, allowing the construction of the β-keto-dioxinone key intermediate. Two-photon absorption cross-section measurements of the fluorenyl epicocconone analogues show a structure dependency with values ranging from 60 to 280 GM and live cell imaging show intense staining of intracellular vesicle-like structures around the nucleus.

Biosynthesis, Extraction and Characterization of Extracellular Polymeric Substances (EPSs) from Aspergillus clavatus

Six fungal strains were isolated from El-Sella ore material (Fusarium solani, Penicillium purpurogenum, Aspergillus niger, Aspergillus clavatus, Cladosporium herbarum and Epicoccum nigrum), and screened for exopolysaccharides (EPSs) production. In this study, the most promising fungus producing exopolysaccharides (EPSs) was A. clavatus which was identified according to microscopic morphological feature.

The Purification, Characterization, and Biological Activity of New Polyketides from Mangrove-Derived Endophytic Fungus Epicoccum nigrum SCNU-F0002.

Six new polyketides, including one coumarin (1), two isocoumarins (2 and 3), dihydroradicinin (4), and two benzofuranone derivatives (7 and 8), together with seven known analogues (5–6 and 9–13) were isolated from the culture of the mangrove endophytic fungus Epicoccum nigrum SCNU-F0002. The structures were elucidated on the interpretation of spectroscopic data. The absolute configuration of Compounds 2 and 3 were determined by comparison of their ECD spectra with the data of their analogue dihydroisocoumarins described in the literature. The absolute configuration of 4 was determined by single-crystal X-ray diffraction. All the compounds were screened for their antioxidant, antibacterial, anti-phytopathogenic fungi and cytotoxic activities. Using a DPPH radical-scavenging assay, Compounds 10–13 showed potent antioxidant activity with IC50 values of 13.6, 12.1, 18.1, and 11.7 μg/mL, respectively. In addition, Compounds 6 and 7 showed antibacterial effects against Bacillus subtilis (ATCC 6538), Escherichia coli (ATCC 8739), and Staphylococcus aureus (ATCC 6538), with MIC values in the range of 25–50 μg/mL.

Cattle grazing alters the interaction of seed-borne fungi and two foliar pathogens of Leymus chinensis in a meadow steppe

Intensive grazing by herbivores lead to major ecological changes in natural grasslands, including severe degeneration. However, the understanding of how grazing affects the incidence of pathogenic and saprotrophic fungi on leaves and seeds of dominant plant species in grasslands is limited. In this study, the presence of two fungal pathogens that cause lesions on leaves of a dominant grass species of the Hulunber meadow steppe in northeast China, Leymus chinensis, as well as saprotrophic fungi associated with lesions, was investigated in plots with different grazing intensities treatments (0, 0.42, 0.63, 0.83, 1.25, and 1.67 cattle ha−1). In addition, seeds of L. chinensis were harvested from plants of the different grazing intensities and the presence of seed-borne fungi, including pathogenic and saprotrophic fungi, were examined by fungal isolation. The results indicated that with the increase of grazing intensity, the incidence of two fungal diseases on leaves of L. chinensis, leaf blotch diseases caused by Leptosphaeria avenaria and Parastagonospora nodorum, decreased. On seeds, the two most frequently isolated fungi were Le. avenaria and P. nodorum, from 57.2% and 40.6% of seeds respectively. At the highest grazing plots, the frequency of isolation of these two fungi to 23.1 and 15.6% respectively. By contrast, the frequency of isolation of Epicoccum nigrum in the highest grazing plots was 88.9%, approximately 10-fold of that in control plots. In dual-culture studies, E. nigrum isolates had inhibitory effects on the growth of isolates of the two leaf pathogens.

Efficiency of Lichenicolous Fungi in Controlling Citrus Lichen Xanthoria parietina

Lichenicolous fungi are not the same as the fungi that is the component of the lichen, which are known as lichenized fungi. This study was carried out to investigate the parasitic fungi which colonizing and attacking thalli and apothecia of citrus lichen Xanthoria parietina and the efficiency of using these fungias lichenicolouss in its control. Several fungi were isolated from decayed thalli and apothecia and identified as Xanthoriicola physciae, Cladosporium sp., Alternaria sp., Drechslera sp., Botryodiplodia sp., Mucor sp., Aspergillus sp., Pestalotiopsis sp., Epicoccum nigrum, Fusarium sp. , and Tellogalla oliveri. Xanthoriicola physciae was the most frequent and aggressive fungus in all collected decayed samples, anatomical investigation of decayed thalli and apothecia caused by Xanthoriicola physciae showed destruction and lytic symptoms on the tissue and formation of black mass production of hypha and conidiospores in the infected thalli and apothecia. All lichenicolous fungi were isolated and cultivated on PDA and Malt yeast extract media, parasitism of lichenicolous fungi was done by spore suspension of lichenicolous fungi to fresh healthy thalli and apothecia and the results of decay and damage were recorded.

Field Fungal Diversity in Freshly Harvested Japonica Rice

Rice is a major food crop in China and Japonica rice production in Heilongjiang Province ranks No.1 in total annual rice production in the country. Rice is prone to invasion by fungi and mycotoxins produced by the fungi are proven to be serious threats to human health. The objective of the present study was to investigate fungal diversity of freshly harvested rice in the four main cultivation regions of Heilongjiang Province in order to find the difference of dominant fungi among the four regions. Through high throughput sequencing we detected Ascomycota accounts for absolute dominant phylum; Dothideomycetes, Sordariomycetes, Tremellomycetes, Microbotryomycetes, and Eurotiomycetes were dominant classes; Capnodiales, Hypocreales, and Pleosporales were the main orders; Cladosporiaceae, Pleosporaceae, Nectriaceae, Clavicipitaceae, Tremellaceae, Phaeosphaeriaceae, Trimorphomycetaceae, Sporidiobolaceae, Bionectriaceae, and Trichocomaceae were major family; Cladosporium, Epicoccum, Fusarium, and Alternaria were the most abundant phylotypes at genus level; Epicoccum nigrum, Gibberella zeae, and Fusarium proliferatum were the dominant fungal species. Great fungal diversity was observed in the rice samples harvested in the four major Japonica rice-growing regions in Heilongjiang province. However, no significant difference in diversity was observed among the four regions, likely due to the relatively close geographical proximity leading to very similar climatic conditions. Since some of the fungal species produce mycotoxins, it is necessary to take precautions to ensure the rice is stored under safe conditions to prevent the production of mycotoxins. This is the first report on investigation of field fungal diversity in freshly harvested Japonica rice in Heilongjiang Province in China.