Morphological, molecular characterization, plant pathogenicity and biocontrol of Cladosporium complex groups associated with faba beans.

Vicia faba (faba bean) is one of the most significant leguminous crops. The faba bean is specialized by maximum nutritional value, in energy and protein content, which leads it to be suitable for food and feed production. Diseases caused with fungi are amongst the biotic factors responsible for decreasing in faba bean yields. In this work, Cladosporium isolates were recorded in cultivated faba bean leaves and pods collected from markets in Qena, Upper Egypt; morphological features and molecular characterization based on actin gene were performed. The ability of the pathogens to cause disease in faba bean seedlings and the biocontrol method to avoid the pathogenic effect of Cladosporium were determined. Results showed that Cladosporium is the main genera isolated from faba beans, and the morphological criteria showed presence of three species complex groups of Cladosporium (C. cladosporioides, C. herbarum and C. sphaerospermum) and the confirmation with molecular characterization revealed the existence of four species in the three groups. All the 26 tested strains of Cladosporium were able to cause leaf lesions on Vicia faba seedlings with different levels. Chaetomium globosum is a biocontrol agent could inhibit the growth of the majority strains of Cladosporium.

Improving the thermostability of a thermostable endoglucanase from Chaetomium thermophilum by engineering the conserved noncatalytic residue and N-glycosylation site.

Endoglucanases provide an attractive avenue for the bioconversion of lignocellulosic materials into fermentable sugars to supply cellulosic feedstock for biofuels and other value-added chemicals. Thermostable endoglucanases with high catalytic activity are preferred in practical processes. To improve the thermostability and activity of the thermostable ß-1,4-endoglucanase CTendo45 isolated from the thermophilic fungus Chaetomium thermophilum, structure-based rational design was performed by using site-directed mutagenesis. When inactivated mutation of the unique N-glycosylation sequon (N88-E89-T90) was implemented and the conserved Y173 residue was substituted with phenylalanine, a double mutant T90A/Y173F demonstrated enzymatic activity that dramatically increased 2.12- and 1.82-fold towards CMC-Na and ß-D-glucan, respectively. Additionally, T90A/Y173F exhibited extraordinary heat endurance after 300 min of incubation at elevated temperatures. This study provides a valid approach to the improvement of enzyme redesign protocols and the properties of this endoglucanase mutant distinguish it as an excellent candidate enzyme for industrial biomass conversion.

Conventional detection and quantification real-time PCR of the pks-1 gene of Chaetomium globosum.

Chaetomium globosum is known as a potential biocontrol indicator against various soil and seedborne pathogens. Precise data are necessary for population monitoring of C. globosum for its effective use in agriculture. A sequence-characterized amplified region marker has been applied for the detection of this biocontrol agent, which will help to detect C. globosum at the site of its application. Out of 17 isolates of C. globosum, only 8 isolates of C. globosum amplified a monomorphic band of 1,900 bp. C. globosum is known for producing chaetoglobosin A. The pks-1 gene is unique in C. globosum in that it is involved in chaetoglobosin A production, melanin formation, and sporulation. Real-time PCR of pks-1 was used to compare the expressions of the pks-1 gene and chaetoglobosin A biosynthesis and sporulation. It was found that the sporulation of C. globosum was associated with the levels of pks-1 gene expression; Cg2 isolate showed high expression of the pks-1 gene, 41.21%, and also produced a great number of spores and perithecia. The association between the pks-1 gene expression and chaetoglobosin A production was estimated. The Pks-1 gene was expressed by all C. globosum isolates except one isolate, C1, which is another species of Chaetomium. In addition, all C. globosum isolates produced chaetoglobosin A with different concentrations and did not express the same levels of pks-1. This finding may be a result of the solvent type used in the extraction.

The potential of endophytic fungi isolated from cucurbit plants for biocontrol of soilborne fungal diseases of cucumber.

The ability of endophytic fungi isolated from cucurbit plants to suppress soilborne diseases and the relationship between antagonism and disease suppression were studied. In dual culture tests of 1044 strains of 90 genera and three pathogenic fungi, 47.1 % of the endophytic fungal strains showed antagonistic effects on at least one pathogen; 186 strains against Rhizoctonia solani, 371 strains against Sclerotinia sclerotiorum, and 403 strains against Fusarium oxysporum f. sp. cucumerinum. The main antagonistic type of the strains of one genus generally was identical to one pathogen. In the pot experiment of cucumber inoculated with R. solani and endophytic fungi, 74.3 % and 33.3 % of 288 strains showed control efficacy of more than 50 % and more than 80 % on cucumber Rhizoctonia root rot respectively. These strains were mostly distributed in Fusarium, Chaetomium, Colletotrichum and Acrocalymma. There were some differences in the proportion of strains with better disease suppressive effects between strain sources. No significant correlation existed between the disease suppression of a strain in vivo and its antagonism against the pathogen in vitro. Most growth-promoting strains had good suppressive effects on cucumber Rhizoctonia root rot. In this study, 82 endophytic fungal strains had good disease suppressive effects and no obvious adverse effects on cucumber growth, and 35 of them showed obvious growth-promoting effects, which suggested that endophytic fungi from cucurbit plants have excellent potential for plant disease control.

Chaetomium atrobrunneum causing human eumycetoma: The first report.

In this communication, a case of black grain eumycetoma produced by the fungus C. atrobrunneum is reported. The patient was initially misdiagnosed with M. mycetomatis eumycetoma based on the grains' morphological and cytological features. However, further aerobic culture of the black grains generated a melanised fungus identified as C. atrobrunneum by conventional morphological methods and by internal transcribed spacer 2 (ITS2) ribosomal RNA gene sequencing. This is the first-ever report of C. atrobrunneum as a eumycetoma-causative organism of black grain eumycetoma. It is essential that the causative organism is identified to the species level, as this is important for proper patient management and to predict treatment outcome and prognosis.

Anticancer potential of NF-κB targeting apoptotic molecule "flavipin" isolated from endophytic Chaetomium globosum.

BACKGROUND: Anticancer compounds from natural sources have drawn attention due to their structural diversity and relatively lesser side effects. Endophytic fungi are one such natural resource from, which plethoras of anticancerous compounds have been isolated. PURPOSE: The objective of the study was to isolate and characterize the bioactive metabolite from Chaetomium globosum that exhibits astonishing antiproliferative activity against cancerous cell lines. METHODS: Flavipin was isolated by bioassay-guided fractionation and identified using FT-IR, EI-MS and NMR studies. MTT assay was used to determine the cytotoxicity. Fluorescent staining (AO/EB) and DNA fragmentation studies confirmed the occurrence of apoptosis. Real time PCR and Western blotting were used to analyze the expression of apoptosis related genes and its proteins, respectively. RESULTS: Flavipin inhibited proliferation of A549, HT-29 and MCF-7 cancer cells in dose dependent manner with an IC50 concentration of 9.89 µg/ml, 18 µg/ml and 54 µg/ml, respectively, whereas it was comparatively less sensitive (IC50 = 78.89 µg/ml) against normal cell line (CCD-18Co). At IC50 concentration cancerous cells exhibited cell shrinkage and fragmentation of DNA, which indicated that flavipin induced apoptotic cell death. In treated cells there is an up-regulation of p53 gene and its associated protein, whereas reciprocal expression was observed in BCL-2 gene and its protein. Furthermore, western blotting results also showed down-regulation of NFκB. CONCLUSION: This is the first report on the antiproliferative activity of flavipin isolated from endophytic C. globosum and also proposed that interaction of flavipin with NFкB could be a possible mechanism for this activity. Flavipin induced apoptosis at low concentrations in cancer cell lines (A549, HT-29) and exhibited itself as a potential anticancer agent.

[Isolation,screening and identification of endophytic fungi and detection of its antifungal effects against Alternaria panax].

To obtain biocontrol fungus for Alternaria panax,the antifungal effects of one strain of endophytic fungi isolated from leaves of healthy ginseng were screened and evaluated by using dual-culture method,and the taxonomic assignment of the screened strain was identified based on the morphological characters and ITS sequence analysis. The results of dual-culture showed that one of the endophytes marked as FS-01 had good antifungal effects and the inhibitory rates of FS-01 strain to A. panax was( 60. 21±0. 12) %.The hyphae junction of the both strains,A. panax dissolved,broke and winded,while the hyphae of FS-01 strain remained normal. The inhibitory rates of non-sterilized FS-01 strain fermentation liqud was( 13. 94±0. 21) %. Strain FS-01 identified as Chaetomium globosum.

Wastewater-Agar as a selection environment: A first step towards a fungal in-situ bioaugmentation strategy.

Viable and metabolically active fungi in toxic mixed liquors, treating landfill leachates and municipal wastewaters, were identified by culture depending methods. A selective culture medium consisting of wastewater and agar (WA) restrained fungi that could be randomly present (94% of the 51 taxa retrieved on WA were sample-specific), overcoming the problem of fast growing fungi or mycoparasite fungi. Moreover, WA allowed the isolation of fungi with a possible role in the degradation of pollutants typically present in the two wastewaters. Phoma medicaginis var. medicaginis, Chaetomium globosum, and Geotrichum candidum were mainly found in municipal wastewater, whereas Pseudallescheria boydii, Scedosporium apiospermum, Aspergillus pseudodeflectus, and Scopulariopsis brevicaulis were typical of landfill leachate.

Subcutaneous phaeohyphomycosis caused by Amesia atrobrunnea in Kuwait.

The recently described genus Amesia encompasses four species but only Amesia atrobrunnea (=Chaetomium atrobrunneum) is known to be pathogenic to humans. Here, we describe a case of subcutaneous phaeohyphomycosis in Kuwait in an apparently immunocompetent patient diagnosed by direct microscopy of the infected tissue and culture. The identity of A. atrobrunnea was established by typical morphological characteristics and by sequencing of internally transcribed spacer (ITS) region and D1/D2 domains of rDNA. To the best of our knowledge, this is the first report documenting etiologic role of this species in causing a locally invasive subcutaneous infection.

The screening and identification of the biological control fungi Chaetomium spp. against wheat common root rot.

Bipolaris sorokiniana is a soil-borne fungal pathogen causing common root rot in wheat, and is difficult to control through chemical and agricultural means. Chaetomium spp. have been documented as potential biological control agents for plant diseases. In this study, seven Chaetomium strains were screened for their abilities to control B. sorokiniana on agar plates. Strain 22-10 significantly inhibited the growth of B. sorokiniana on potato dextrose agar plates, up to 66.7%. Its filtrate of liquid culture also inhibited the mycelial growth of B. sorokiniana, indicating that strain 22-10 produced secondary metabolites against B. sorokiniana. The incidence and disease indexes of common root rot significantly decreased in wheat after treatment with the crude extract of strain 22-10. Six active compounds were purified from crude extract of this fungus culture against B. sorokiniana. Chaetoviridin A showed the highest efficiency to inhibit the growth of B. sorokiniana. Strain 22-10 was identified as Chaetomium globosum based on phylogenetic analysis of the rDNA internal transcribed spacer region and microscopic characteristics. The high control efficiency of strain 22-10 of C. globosum against B. sorokiniana suggested it has potential to be a biocontrol agent for B. sorokiniana.

Characterization, culture medium optimization and antioxidant activity of an endophytic vitexin-producing fungus Dichotomopilus funicola Y3 from pigeon pea [Cajanus cajan (L.) Millsp.].

AIMS: The aim of this study was to characterize a fungal endophyte Y3 from pigeon pea (Cajanus cajan [L.] Millsp), as a novel producer of vitexin, and its culture medium optimization and antioxidant activity. METHODS AND RESULTS: The endophyte from the leaves of pigeon pea was identified as Dichotomopilus funicola by the morphological and molecular characteristics. The most important medium variables affecting vitexin production in liquid culture of D. funicola Y3 were screened by Plackett-Burman design, and three culture medium constituents (i.e. l-phenylalanine, salicylic acid and CuSO4 ·5H2 O) were identified to play significant roles in vitexin production. The most significant factors were further optimized using by central composite design with response surface methodology. The DPPH radical-scavenging assay indicated that fungal vitexin exhibited notable antioxidant activity with an EC50 value of 164 µg l-1 . CONCLUSIONS: First, a novel endophyte vitexin-producing Dichotomopilus funicola Y3 was isolated from pigeon pea (Cajanus cajan[L.] Millsp.). The maximum vitexin yield was obtained as 78·86 mg l-1 under the optimum culture medium constituents: 0·06 g l-1  l-phenylalanine, 0·21 g l-1 salicylic acid, and 0·19 g l-1 CuSO4 ·5H2 O in medium, which is 4·59-fold higher than that in the unoptimized medium. Also, fungal vitexin clearly demonstrated its antioxidant potential. SIGNIFICANCE AND IMPACT OF THE STUDY: These findings provide an alternative source for large-scale production of vitexin by endophytic fungal fermentation and have a promising prospect in food and pharmaceutical industry.

Hepatoprotective evaluation and isolation of the major secondary metabolites from the ethyl acetate extract of liquid culture filtrate of Chaetomium globosum.

The aim of the present study was to evaluate the hepatoprotective activity of ethyl acetate extract of the liquid culture filtrate of Chaetomium globosum fungus (family Chaetomiaceae). Rats were intraperitoneally injected by CCl4 (0.5ml/kg) twice a week for six consecutive weeks. Treatment tacks (250mg/kg) place at the same time of CCl4 induction and with the same duration. The evaluation was done through determination of liver function indices; aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), and total serum protein content. In addition, the oxidative stress markers; hepatic glutathione content (GSH), hepatic malondialdehyde (MDA), hepatic superoxide dismutase (SOD), and hepatic total protein were estimated. Moreover, the liver architectures were also examined. Isolation and identification of the main secondary metabolites were identified. Seven volatile compounds were identified from the plain chloroform fraction where, 1-Cyclopentyl-2,2-dimethyl-1-propanol (54.63%) was presented as the major compound. Eleven compounds were also identified from the fraction eluted by chloroform: methanol (85:15). 1,5,5-Trimethyl-6-methylene-1-cyclohexene (25.79%) and Norbornan-2-one (26.84%) are presented as the major compounds of this fraction. In conclusion, the extract recorded hepatoprotective effect by ameliorating the biochemical parameters under investigation. The liver histopathological pictures confirmed our results.

Changes in soil microbial communities after 10 years of winter wheat cultivation versus fallow in an organic-poor soil in the Loess Plateau of China.

Agricultural management methods, such as cultivation or fallowing, have led to significant changes in soil fertility and hence, crop yield. Such changes may have stemmed from changes in soil microbial communities and associated biogeochemical processes. This phenomenon is particularly true in organic-poor soil in the Loess Plateau of China. In this study, we examined three existing soil management regimes as part of a 10-year field experiment and evaluated their effects on fungal and bacterial community structures by performing high-throughput 454 pyrosequencing. These management regimes were (i) fertilized winter wheat (Triticum aestivum L.) (FW), (ii) continuous natural fallow with weeds but without crop grown (NF), and (iii) continuous bare fallow without weeds or crop grown (BF). After 10 years, soil organic carbon (SOC), microbial biomass carbon (MBC), and available potassium (K) concentrations were highest in NF. Soil N behaved differently, with BF obtaining the highest nitrate nitrogen (N). Meanwhile, slight differences in total N (TN) were observed among FW, NF, and BF. Available phosphorus (P) was highest and available K was lowest in FW. Microbial communities were dominated by Ascomycota (59.1% of fungal sequences), and Acidobacteria, Actinobacteria, Bacteroidetes, Firmicutes, and Proteobacteria (75.7% of bacterial sequences) in FW, NF and BF at the phylum level. Soil management regimes did not affect the fungal and bacterial richness and diversity but significantly modified their community compositions. Compared with FW, the abundances of Ascomycota (fungi phylum) and Alternaria, Gibberella, and Emericella (fungi genus) were increased by NF, whereas the values of Chaetomium, Humicola, and Cryptococcus (fungi genus) were decreased by BF. The abundances of Verrucomicrobia (bacteria phylum), and Steroidobacter (bacteria genus) were increased by NF, and Bacteroides (bacteria genus) was increased by BF. Canonical correspondence analysis showed that SOC, available P, and TN might be the key factors in community formation. Therefore, the decadal absence of plants (BF) affected soil fertility by increased available K and nitrate N, whileas natural fallow (NF) affected soil fertility by increased SOC, available K, and MBC, and they all changed fungal and bacterial community compositions.

Corneal ulcer due to a rare coelomycetes fungus Chaetomium strumarium: Case report and global review of Chaetomium keratomycosis.

We present a rare case of corneal ulcer caused by a species of a coelomycetes fungus, Chaetomium strumarium. This fungal genus is a rare causative agent of keratomycosis, with only a handful of cases reported. The clinical presentation, investigative techniques, and preliminary management of our patient are reported. The cases reported in global literature are also summarized in a tabular form in the discussion.

Relation of indoor and outdoor airborne fungal spore levels in the Kansas City metropolitan area.

BACKGROUND: Environmental control is an important component of asthma management for persons with asthma. A damp indoor environment and elevated airborne spore levels are factors in housing environmental control. OBJECTIVES: We investigated if indoor airborne fungal spore levels correlated with outdoor ground-level airborne fungal spores or outdoor centrally collected spore levels as to types and abundance. METHODS: Air collections were taken from home interiors, outdoor areas adjacent to the homes, and at a central location in the metropolitan area at the approximate same time. All air collections were examined and enumerated microscopically, and airborne spore estimates per cubic meter of air were reported for total fungal spores and for 11 identifiable spore groups. RESULTS: The 244 homes in the study were typical of the North American Midwest. The overall mean total spore counts in spores per cubic meter of air was indoors (4076 spores/m3), outdoors at ground level (8899 spores/m3), and outdoor metropolitan area (8342 spores/m3). All of the major indoor taxa were strongly correlated with the mean total spores present in the home. Total outdoor ground spore levels were highly correlated with levels of major outdoor taxa, such as ascospores and Cladosporium. Correlations of indoor spore levels with outdoor spore levels are strong for most major outdoor taxa. Indoor Aspergillus-Penicillium and Chaetomium are significantly correlated between indoor and local ground-level outdoor air. CONCLUSION: Although conditions may exist where indoor or outdoor spore levels were not well aligned, in most circumstances, the outdoor airborne spore community was reflected in the indoor airborne spore community.

Pre-contamination of new gypsum wallboard with potentially harmful fungal species.

Gypsum wallboard is a popular building material, but is also very frequently overgrown by Stachybotrys chartarum after severe and/or undetected water damage. The purpose of this study was to determine whether Stachybotrys and other fungi frequently isolated from wet gypsum wallboard are already present in the panels directly from the factory. Surface-disinfected gypsum disks were wetted with sterile water, sealed, and incubated for 70 days. The results showed that Neosartorya hiratsukae (≡ Aspergillus hiratsukae) was the most dominant fungus on the gypsum wallboard followed by Chaetomium globosum and Stachybotrys chartarum. Our results suggest that these three fungal species are already embedded in the materials, presumably in the paper/carton layer surrounding the gypsum core, before the panels reach the retailers/building site.

Potentially harmful secondary metabolites produced by indoor Chaetomium species on artificially and naturally contaminated building materials.

The presence of the fungal genus Chaetomium and its secondary metabolites in indoor environments is suspected to have a negative impact on human health and well-being. About 200 metabolites have been currently described from Chaetomium spp., but only the bioactive compound group, chaetoglobosins, have been screened for and thus detected in buildings. In this study, we used a liquid chromatography high-resolution mass spectrometry approach to screen both artificially and naturally infected building materials for all the Chaetomium metabolites described in the literature. Pure agar cultures were also investigated to establish differences between metabolite production in vitro and on building materials as well as in comparison with non-indoor reference strains. On building materials, six different chaetoglobosins were detected in total concentrations of up to 950 mg/m2 from Chaetomium globosum along with three different chaetoviridins/chaetomugilins in concentrations up to 200 mg/m2 . Indoor Chaetomium spp. preferred wood-based materials over gypsum, both in terms of growth rate and metabolite production. Cochliodones were detected for the first time on all building materials infected by both C. globosum and Chaetomium elatum and are thus candidates as Chaetomium biomarkers. No sterigmatocystin was produced by Chaetomium spp. from indoor environment.

Polyphasic characterisation of Chaetomium species from soil and compost revealed high number of undescribed species.

This study investigated 46 Chaetomium strains isolated from soil and compost from China. In total 14 species were recognised, of which seven were described as new species (i.e. Chaetomium angulare, Chaetomium cirrhata, Chaetomium heterothallicum, Chaetomium laterale, Chaetomium longiciliata, Chaetomium microthecia, Chaetomium uniseriatum). Growth temperature profiles of these fungi revealed that 11 species are mesophilic; C. angulare and Chaetomium jodhpurense are thermotolerant; Chaetomium thermophilum var. dissitum is thermophilic, with temperature maxima above 50 °C. Among the 46 strains, 39 were shown to be homothallic. Mating experiments were conducted for the remaining seven strains that are morphologically and phylogenetically closely related. The results of the mating experiment, together with the four-locus (ITS, LSU, RPB2, TUB) phylogeny and a pairwise homoplasy index (PHI) test, supported the division of these seven additional strains into two heterothallic species that are herein described as C. heterothallicum and C. uniseriatum. A three-locus (ITS, LSU, TUB) phylogenetic tree based on all currently accepted species that have available type-derived sequences revealed that Chaetomium species clearly grouped in six phylogenetic groups which showed a certain correspondence with their morphology and temperature profiles.

Cytoglobosins H and I, New Antiproliferative Cytochalasans from Deep-Sea-Derived Fungus Chaetomium globosum.

Cytoglobosins H (1) and I (2), together with seven known cytochalasan alkaloids (3-9), were isolated from the deep-sea-derived fungus Chaetomium globosum. The structures of new compounds 1 and 2 were elucidated by extensive 1D and 2D NMR and mass spectroscopic data. All the compounds were evaluated for their antiproliferative activities against MDA-MB-231 human breast cancer cells, LNCaP human prostate cancer cells, and B16F10 mouse melanoma cells. Compound 6 showed significant antiproliferative activity against LNCaP and B16F10 cell lines with IC50 values of 0.62 and 2.78 µM, respectively. Further testing confirmed that compound 6 inhibited the growth of LNCaP cells by inducing apoptosis.