Lindgomyces angustiascus, (Lindgomycetaceae, Pleosporales, Dothideomycetes), a new lignicolous species from freshwater habitats in the USA

Fungal diversity notes 1512-1610: taxonomic and phylogenetic contributions on genera and species of fungal taxa

This article is the 14th in the Fungal Diversity Notes series, wherein we report 98 taxa distributed in two phyla, seven classes, 26 orders and 50 families which are described and illustrated. Taxa in this study were collected from Australia, Brazil, Burkina Faso, Chile, China, Cyprus, Egypt, France, French Guiana, India, Indonesia, Italy, Laos, Mexico, Russia, Sri Lanka, Thailand, and Vietnam. There are 59 new taxa, 39 new hosts and new geographical distributions with one new combination. The 59 new species comprise Angustimassarina kunmingense, Asterina lopi, Asterina brigadeirensis, Bartalinia bidenticola, Bartalinia caryotae, Buellia pruinocalcarea, Coltricia insularis, Colletotrichum flexuosum, Colletotrichum thasutense, Coniochaeta caraganae, Coniothyrium yuccicola, Dematipyriforma aquatic, Dematipyriforma globispora, Dematipyriforma nilotica, Distoseptispora bambusicola, Fulvifomes jawadhuvensis, Fulvifomes malaiyanurensis, Fulvifomes thiruvannamalaiensis, Fusarium purpurea, Gerronema atrovirens, Gerronema flavum, Gerronema keralense, Gerronema kuruvense, Grammothele taiwanensis, Hongkongmyces changchunensis, Hypoxylon inaequale, Kirschsteiniothelia acutisporum, Kirschsteiniothelia crustaceum, Kirschsteiniothelia extensum, Kirschsteiniothelia septemseptatum, Kirschsteiniothelia spatiosum, Lecanora immersocalcarea, Lepiota subthailandica, Lindgomyces guizhouensis, Marthe asmius pallidoaurantiacus, Marasmius tangerinus, Neovaginatispora mangiferae, Pararamichloridium aquisubtropicum, Pestalotiopsis piraubensis, Phacidium chinaum, Phaeoisaria goiasensis, Phaeoseptum thailandicum, Pleurothecium aquisubtropicum, Pseudocercospora vernoniae, Pyrenophora verruculosa, Rhachomyces cruralis, Rhachomyces hyperommae, Rhachomyces magrinii, Rhachomyces platyprosophi, Rhizomarasmius cunninghamietorum, Skeletocutis cangshanensis, Skeletocutis subchrysella, Sporisorium anadelphiae-leptocomae, Tetraploa dashaoensis, Tomentella exiguelata, Tomentella fuscoaraneosa, Tricholomopsis lechatii, Vaginatispora flavispora and Wetmoreana blastidiocalcarea. The new combination is Torula sundara. The 39 new records on hosts and geographical distribution comprise Apiospora guiyangensis, Aplosporella artocarpi, Ascochyta medicaginicola, Astrocystis bambusicola, Athelia rolfsii, Bambusicola bambusae, Bipolaris luttrellii, Botryosphaeria dothidea, Chlorophyllum squamulosum, Colletotrichum aeschynomenes, Colletotrichum pandanicola, Coprinopsis cinerea, Corylicola italica, Curvularia alcornii, Curvularia senegalensis, Diaporthe foeniculina, Diaporthe longicolla, Diaporthe phaseolorum, Diatrypella quercina, Fusarium brachygibbosum, Helicoma aquaticum, Lepiota metulispora, Lepiota pongduadensis, Lepiota subvenenata, Melanconiella meridionalis, Monotosporella erecta, Nodulosphaeria digitalis, Palmiascoma gregariascomum, Periconia byssoides, Periconia cortaderiae, Pleopunctum ellipsoideum, Psilocybe keralensis, Scedosporium apiospermum, Scedosporium dehoogii, Scedosporium marina, Spegazzinia deightonii, Torula fici, Wiesneriomyces laurinus and Xylaria venosula. All these taxa are supported by morphological and multigene phylogenetic analyses. This article allows the researchers to publish fungal collections which are important for future studies. An updated, accurate and timely report of fungus-host and fungus-geography is important. We also provide an updated list of fungal taxa published in the previous fungal diversity notes. In this list, erroneous taxa and synonyms are marked and corrected accordingly.

Freshwater Dothideomycetes

Freshwater Dothideomycetes are a highly diverse group of fungi, which are mostly saprobic in freshwater habitats worldwide. They are important decomposers of submerged woody debris and leaves in water. In this paper, we outline the genera of freshwater Dothideomycetes with notes and keys to species. Based on multigene analyses and morphology, we introduce nine new genera, viz. Aquimassariosphaeria, Aquatospora, Aquihelicascus, Fusiformiseptata, Neohelicascus, Neojahnula, Pseudojahnula, Purpureofaciens, Submersispora; 33 new species, viz. Acrocalymma bipolare, Aquimassariosphaeria kunmingensis, Aquatospora cylindrica, Aquihelicascus songkhlaensis, A. yunnanensis, Ascagilis submersa, A. thailandensis, Bambusicola aquatica, Caryospora submersa, Dictyocheirospora thailandica, Fusiformiseptata crocea, Helicosporium thailandense, Hongkongmyces aquaticus, Lentistoma aquaticum, Lentithecium kunmingense, Lindgomyces aquaticus, Longipedicellata aquatica, Neohelicascus submersus, Neohelicomyces dehongensis, N. thailandicus, Neohelicosporium submersum, Nigrograna aquatica, Occultibambusa kunmingensis, Parabambusicola aquatica, Pseudoasteromassaria aquatica, Pseudoastrosphaeriella aquatica, Pseudoxylomyces aquaticus, Purpureofaciens aquatica, Roussoella aquatica, Shrungabeeja aquatica, Submersispora variabilis, Tetraploa puzheheiensis, T. yunnanensis; 16 new combinations, viz. Aquimassariosphaeria typhicola, Aquihelicascus thalassioideus, Ascagilis guttulaspora, A. queenslandica, A. seychellensis, A. sunyatsenii, Ernakulamia xishuangbannaensis, Neohelicascus aquaticus, N. chiangraiensis, N. egyptiacus, N. elaterascus, N. gallicus, N. unilocularis, N. uniseptatus, Neojahnula australiensis, Pseudojahnula potamophila; 17 new geographical and habitat records, viz. Aliquandostipite khaoyaiensis, Aquastroma magniostiolata, Caryospora aquatica, C. quercus, Dendryphiella vinosa, Ernakulamia cochinensis, Fissuroma neoaggregatum, Helicotruncatum palmigenum, Jahnula rostrata, Neoroussoella bambusae, N. leucaenae, Occultibambusa pustula, Paramonodictys solitarius, Pleopunctum pseudoellipsoideum, Pseudocapulatispora longiappendiculata, Seriascoma didymosporum, Shrungabeeja vadirajensis and ten new collections from China and Thailand, viz. Amniculicola guttulata, Aquaphila albicans, Berkleasmium latisporum, Clohesyomyces aquaticus, Dictyocheirospora rotunda, Flabellascoma fusiforme, Pseudoastrosphaeriella bambusae, Pseudoxylomyces elegans, Tubeufia aquatica and T. cylindrothecia. Dendryphiella phitsanulokensis and Tubeufia roseohelicospora are synonymized with D. vinosa and T. tectonae, respectively. Six orders, 43 families and 145 genera which belong to freshwater Dothideomycetes are reviewed. Of these, 46 genera occur exclusively in freshwater habitats. A world map illustrates the distribution of freshwater Dothideomycetes.

Subcutaneous phaeohyphomycosis caused by Hongkongmyces snookiorum in a kidney transplant patient: a case report

BACKGROUND

Morbidity and mortality in transplant patients is increased by infection caused mainly by rare opportunistic pathogens. The present study reports a case where Hongkongmyces snookiorum caused subcutaneous phaeohyphomycosis in a kidney transplant patient.

CASE PRESENTATION

A 47-year old Chinese woman with chronic kidney disease 5 underwent kidney transplantation 3 years ago. Her regular medications included Tacrolimus (1 mg, two times daily), Mycophenolate Mofetil (two times 250 mg, twice daily) and Prednisone acetate tablets (5 mg daily). Eighteen months ago, her proximal right index finger was red, painful and swollen. After admission, a hard and fluctuating 1 cm × 1 cm abscess was found on the dorsal side of the right index finger. Gram and fluorescence staining of a direct smear of a syringe extraction from the abscess revealed presence of filamentous fungi. White velvet colonies (2-3 mm) were found on blood plate and Sabouraud glucose agar (SGA) after 1 week, and grey aerial hyphae were observed. After 15 days, a 26 mm gray colony was also observed on SGA. The homology between this filamentous fungus and Hongkongmyces snookiorum ILLS00125755 (Genbank Sequence ID: MH161189.1) was 99.66%. An in vitro antifungal susceptibility test showed that this filamentous fungus was sensitive to azoles such as itraconazole and voriconazole.

CONCLUSIONS

We report an opportunistic fungus infection caused by Hongkongmyces snookiorum in a transplant patient. Our finding shows that prevention of subcutaneous fungal infection is necessary for kidney transplantation patients.

qNMR for profiling the production of fungal secondary metabolites

Analysis of complex mixtures is a common challenge in natural products research. Quantitative nuclear magnetic resonance spectroscopy offers analysis of complex mixtures at early stages and with benefits that are orthogonal to more common methods of quantitation, including ultraviolet absorption spectroscopy and mass spectrometry. Several experiments were conducted to construct a methodology for use in analysis of extracts of fungal cultures. A broadly applicable method was sought for analysis of both pure and complex samples through use of an externally calibrated method. This method has the benefit of not contaminating valuable samples with the calibrant, and it passed scrutiny for line fitting and reproducibility. The method was implemented to measure the yield of griseofulvin and dechlorogriseofulvin from three fungal isolates. An isolate of Xylaria cubensis (coded MSX48662) was found to biosynthesize griseofulvin in the greatest yield, 149 ± 8 mg per fermentation, and was selected for further supply experiments. Copyright © 2016 John Wiley & Sons, Ltd.

α-Pyrone derivatives, tetra/hexahydroxanthones, and cyclodepsipeptides from two freshwater fungi

Eighteen (1-18) and seven (1, 4, 6-8, 17 and 18) compounds were isolated from organic extracts of axenic cultures of two freshwater fungi Clohesyomyces sp. and Clohesyomyces aquaticus (Dothideomycetes, Ascomycota), respectively. Compounds 1-12 belong to the α-pyrone class of natural products, compounds 13 and 14 were tetrahydroxanthones, compounds 15 and 16 were hexahydroxanthones, while compounds 17 and 18 were cyclodepsipeptides. The structures were elucidated using a set of spectroscopic and spectrometric techniques. The absolute configurations of compounds 2, 3, 6, and 7 were assigned via a modified Mosher's ester method using ¹H NMR data. The relative configurations of compounds 14-16 were determined through NOE data. Compounds 1, 2, 6, 8, 13, 14, and 15 were found to inhibit the essential enzyme bacterial peptidyl-tRNA hydrolase (Pth1), with (13; secalonic acid A) being the most potent. Compounds 1 and 4-18 were also evaluated for antimicrobial activity against an array of bacteria and fungi but were found to be inactive.

Acetophenone derivatives from a freshwater fungal isolate of recently described Lindgomyces madisonensis (G416)

The exploration of freshwater ascomycetes, which have undergone only limited investigation, may provide opportunities both to characterize new genera/species of fungi and to uncover new chemical diversity. In this study, seven acetophenone derivatives, madisone, 4'-methoxymadisone, dehydromadisone, 2″-methoxymadisone, dihydroallovisnaginone, dimadisone, and 4'-methoxydimadisone were characterized from an organic extract of a recently described Lindgomyces madisonensis (G416) culture, which was isolated from submerged wood collected in a stream in North Carolina. Madisone, dehydromadisone, 2″-methoxymadisone, dimadisone and 4'-demethoxydimadisone have not been reported previously, while 4'-methoxymadisone and dihydroallovisnaginone were previously unknown as natural products. Their structures were assigned on the basis of NMR and HRESIMS data, with the structure of madisone supported by X-ray crystallography. The antimicrobial activities of madisone, 4'-methoxymadisone and dihydroallovisnaginone were evaluated against a panel of bacteria and fungi. A heat map analysis of the surface of a G416 culture showed that most of the isolated compounds concentrated in the guttate compared with the vegetative mycelium of the fungus.

Minutisphaerales (Dothideomycetes, Ascomycota): a new order of freshwater ascomycetes including a new family, Minutisphaeraceae, and two new species from North Carolina, USA

Minutisphaera is a recently established genus of freshwater Dothideomycetes characterized by small, globose to subglobose or apothecioid, erumpent to superficial, brown ascomata; fissitunicate, eight-spored, ovoid to obclavate asci; and 1-2-septate, clavate to broadly fusiform, hyaline to pale brown ascospores with or without a gelatinous sheath and filamentous appendages. The genus currently contains two species: M. fimbriatispora, the type species, and M. japonica. The higher-level phylogenetic relationship of Minutisphaera within the Dothideomycetes currently is unresolved. To establish the phylogenetic position of Minutisphaera within the Dothideomycetes and evaluate the phylogenetic affinities of newly collected Minutisphaera-like taxa, we sequenced three rDNA regions-18S, ITS1-5.8SITS2 (ITS) and 28S nuc rDNA, and a protein-coding gene, MCM7, for newly collected strains of Minutisphaera. Based on maximum likelihood and Bayesian analyses of a combined dataset (18S and 28S) composed of 167 taxa, a more refined dataset (28S and MCM7) comprising 52 taxa and a separate ITS dataset, and an examination of morphology, we describe and illustrate two new species of Minutisphaera. The Minutisphaera clade was strongly supported within the Dothideomycetes with likelihood and Bayesian statistics but did not share phylogenetic affinities with any existing taxonomic group within the Dothideomycetes. We therefore establish a new order, Minutisphaerales, and new family, Minutisphaeraceae, for this monophyletic clade of freshwater ascomycetes. Chemical analysis of the organic extract M. aspera (G427) resulted in isolation and characterization of five known secondary metabolites, of which four were dipeptides (1-4) and one an aromatic polyketide (5). Conversely, two aromatic polyketides (5, 6) were isolated and identified from the organic extract of M. parafimbriatispora (G156-4). The isolated compounds were tested for their antimicrobial activity against an array of bacteria and fungi. Compound 6 showed promising activity against Staphylococcus aureus and Mycobacterium smegmatis with minimal inhibitory concentration values of 30 and 60 μg/mL, respectively.

Lindgomycin, an Unusual Antibiotic Polyketide from a Marine Fungus of the Lindgomycetaceae

An unusual polyketide with a new carbon skeleton, lindgomycin (1), and the recently described ascosetin (2) were extracted from mycelia and culture broth of different Lindgomycetaceae strains, which were isolated from a sponge of the Kiel Fjord in the Baltic Sea (Germany) and from the Antarctic. Their structures were established by spectroscopic means. In the new polyketide, two distinct domains, a bicyclic hydrocarbon and a tetramic acid, are connected by a bridging carbonyl. The tetramic acid substructure of compound 1 was proved to possess a unique 5-benzylpyrrolidine-2,4-dione unit. The combination of 5-benzylpyrrolidine-2,4-dione of compound 1 in its tetramic acid half and 3-methylbut-3-enoic acid pendant in its decalin half allow the assignment of a new carbon skeleton. The new compound 1 and ascosetin showed antibiotic activities with IC50 value of 5.1 (±0.2) µM and 3.2 (±0.4) μM, respectively, against methicillin-resistant Staphylococcus aureus.

Biosynthetically Distinct Cytotoxic Polyketides from Setophoma terrestris

Sixteen polyketides belonging to diverse structural classes, including monomeric/dimeric tetrahydroxanthones and resorcylic acid lactones, were isolated from an organic extract of a fungal culture Setophoma terrestris (MSX45109) using bioactivity-directed fractionation as part of a search for anticancer leads from filamentous fungi. Of these, six were new: penicillixanthone B (5), blennolide H (6), 11-deoxy blennolide D (7), blennolide I (9), blennolide J (10), and pyrenomycin (16). The known compounds were: secalonic acid A (1), secalonic acid E (2), secalonic acid G (3), penicillixanthone A (4), paecilin B (8), aigialomycin A (11), hypothemycin (12), dihydrohypothemycin (13), pyrenochaetic acid C (14), and nidulalin B (15). The structures were elucidated using a set of spectroscopic and spectrometric techniques; the absolute configurations of compounds 1-10 were determined using ECD spectroscopy combined with time-dependent density functional theory (TDDFT) calculations, while a modified Mosher's ester method was used for compound 16. The cytotoxic activities of compounds (1-15) were evaluated using the MDA-MB-435 (melanoma) and SW-620 (colon) cancer cell lines. Compounds 1, 4, and 12 were the most potent with IC50 values ranging from 0.16 to 2.14 μM. When tested against a panel of bacteria and fungi, compounds 3 and 5 showed promising activity against the Gram-positive bacterium Micrococcus luteus with MIC values of 5 and 15 μg/mL, respectively.

Greensporones: resorcylic acid lactones from an aquatic Halenospora sp

Fourteen new resorcylic acid lactones (1-14) were isolated from an organic extract of a culture of a freshwater aquatic fungus Halenospora sp. originating from a stream in North Carolina. The structures were elucidated using a set of spectroscopic and spectrometric techniques. The absolute configuration of one representative member of the compounds (7) was assigned using X-ray crystallography of an analogue that incorporated a heavy atom, whereas for compounds 8-11, a modified Mosher's ester method was utilized. The relative configurations of compounds 12-14 were determined on the basis of NOE data. Compounds 12-14 were proposed as artifacts produced by intramolecular cycloetherification of the ε-hydroxy-α,β-unsaturated ketone moieties of the parent compounds during the purification processes. The isolated compounds, except for 8 and 12, were tested against the MDA-MB-435 (melanoma) and HT-29 (colon) cancer cell lines. Compound 5 was the most potent, with IC50 values of 2.9 and 7.5 μM, respectively. The compounds were evaluated as TAK1-TAB1 inhibitors but were found to be inactive.

Sorbicillinoid analogs with cytotoxic and selective anti-Aspergillus activities from Scytalidium album

As part of an ongoing project to explore filamentous fungi for anticancer and antibiotic leads, eleven compounds were isolated and identified from an organic extract of the fungus Scytalidium album (MSX51631) using bioactivity-directed fractionation against human cancer cell lines. Of these, eight were a series of sorbicillinoid analogues (1–8), of which four were new [scalbucillin A (2), scalbucillin B (3), scalbucillin C (6), and scalbucillin D (8)], two were phthalides (9–10), and one was naphthalenone (11). Compounds (1–11) were tested in the MDA-MB-435 (melanoma) and SW-620 (colon) cancer cell lines. Compound 1 was the most potent with IC₅₀ values of 1.5 and 0.5 μM, respectively, followed by compound 5, with IC₅₀ values of 2.3 and 2.5 μM at 72 h. Compound 1 showed a 48-h IC₅₀ value of 3.1 μM when tested against the lymphocytic leukemia cell line OSU-CLL, while the nearly identical compound 5 had almost no activity in this assay. Compounds 1 and 5 showed selective and equipotent activity against Aspergillus niger with minimum inhibitory concentration values of 0.05 and 0.04 μg/ml (0.20 and 0.16 μM), respectively. The in vitro hemolytic activity against sheep erythrocytes of compounds 1 and 5 was investigated and were found to provoke 10% hemolysis at 52.5 and 45.0 μg/ml, respectively, indicative of a promising safety factor.

Subcutaneous phaeohyphomycosis in a patient with IgG4-related sclerosing disease caused by a novel ascomycete, Hongkongmyces pedis gen. et sp. nov.: first report of human infection associated with the family Lindgomycetaceae

No members of the freshwater ascomycetes family Lindgomycetaceae have been associated with human infections. We isolated a mould (HKU35(T)) from the biopsy specimen of a patient with invasive foot infection and underlying immunoglobulin G4-related sclerosing disease. Histology showed florid, suppurative, granulomatous inflammation in the dermis, with central microabscess formation surrounded by epithelioid histiocytes, scattered giant cells, and a small number of lymphocytes. A Grocott stain revealed fungal elements in the center of the lesion. On Sabouraud glucose agar, HKU35(T) grew as gray and velvety colonies. Among the members of the family Lindgomycetaceae, HKU35(T) was the only strain that grew at 37°C. Microscopically, only sterile mycelia, but no fruiting bodies, were observed. HKU35(T) was susceptible to itrazonazole, voriconazole, and posaconazole, which was in line with the patient's clinical response to itraconazole treatment. Internal transcribed spacer and partial 18S nuclear rDNA (nrDNA), 28S nrDNA, β-tubulin gene, and EF1α gene sequencing showed that HKU35(T) occupied a unique phylogenetic position, most closely related to but distinct from members of the genera Clohesyomyces and Lindgomyces. We propose a new genus and species, Hongkongmyces pedis gen. et sp. nov., to describe this fungus, which belongs to the family Lindgomycetaceae in the orderPleosporales of class Dothideomycetes. This case also represents the first report of human infection associated with the family Lindgomycetaceae.

Isochromenones, isobenzofuranone, and tetrahydronaphthalenes produced by Paraphoma radicina, a fungus isolated from a freshwater habitat

Six isochromenones (1-6), clearanols F (5) and G (6), one isobenzofuranone (7), and two tetrahydronaphthalene derivatives (8 and radinaphthalenone (9)), were isolated and identified from a culture of the fungus Paraphoma radicina, which was isolated from submerged wood in a freshwater lake. Compounds 5, 6 and 9 were previously unknown. The structures were elucidated using a set of spectroscopic and spectrometric techniques; the absolute configurations of compounds 5 and 6 were determined by comparison of their experimental ECD measurements with values predicted by TDDFT calculations. Compounds 1-9 were evaluated for antimicrobial activity against an array of bacteria and fungi. The inhibitory activity of compound 4 against Staphylococcus aureus biofilm formation was evaluated.

Polyhydroxyanthraquinones as quorum sensing inhibitors from the guttates of Penicillium restrictum and their analysis by desorption electrospray ionization mass spectrometry

The endophytic fungus Penicillium restrictum was isolated from the stems of a milk thistle (Silybum marianum) plant. In culture, the fungus produced distinct red guttates, which have been virtually uninvestigated, particularly from the standpoint of chemistry. Hence, this study examined the chemical mycology of P. restrictum and, in doing so, uncovered a series of both known and new polyhydroxyanthraquinones (1-9). These compounds were quorum sensing inhibitors in a clinical isolate of methicillin-resistant Staphylococcus aureus (MRSA), with IC50 values ranging from 8 to 120 μM, suggesting antivirulence potential for the compounds. Moreover, the spatial and temporal distribution of the polyhydroxyanthraquinones was examined in situ via desorption electrospray ionization-mass spectrometry (DESI-MS) imaging, demonstrating the first application of this technique to a guttate-forming fungus and revealing both the concentration of secondary metabolites at the ventral surface of the fungus and their variance in colonies of differing ages.