Mycobiota and molecular detection of Aspergillus flavus and A. parasiticus aflatoxin contamination of Strawberry (Fragaria ananassa Duch.) fruits

Strawberry fungi were isolated from fresh fruits and juice on the two types of media (Sabouraud dextrose agar, SDA and potato-dextrose agar, PDA) at 28 °C. Nineteen fungal species belong to 12 genera were isolated from fruits and juice on both isolation media. The most common fungal genera and species were Aspergillus flavus, A. niger, Mucor racemosus, Neurospora crassa, Penicillium chrysogenum, Rhizopus stolonifer and Trichoderma harzianum. Twenty A. flavus and A. parasitics isolates were assayed for their abilities to produce aflatoxins. The concentration of aflatoxins ranged between 25.8–75.2 and 23.6–71.1 ng/ml at 350 and 365 nm, respectively. Among A. flavus and A. parasiticus strains tested, aflatoxin B contributed 30–60% of total isolates. However, G type contributed 85–90%. The R_f values of B₁, B₂, G₁ and G₂ were 0.79, 0.61, 0.44 and 0.32, respectively. High-performance liquid chromatography analysis of extracts revealed the presence of aflatoxins with variable levels.     

Penicillium siamensis sp. nov., from Thailand soil

Fungal flora of 20 samples of lentil seeds collected from Assiut governorate, Egypt, were studied. Seventeen genera and 13 species were isolated on glucose- (15 genera and 27 species), cellulose-(15 genera and 25 species)Czapek's agar media at 28 °C. The most common species were as follows: on glucose-Czapek's agar, Aspergillus fumigatus, A. niger, A. flavus, A. terreus, Penicillium notatum and Rhizopus oryzae and on cellulose agar, A. fumigatus, A. niger, A. flavus and P. notatum. Thin layer chromatographic (TLC) analysis and a biological test (Artemia salina) indicated the presence and the toxicity of aflatoxin in the extract of one sample (aflatoxins B₁, B₂, G₁ and G₂, at 20 mg/kg, total). This is the first report of the natural occurrence of aflatoxins in lentils.     

Composition of the fungal flora of four cereal grains in Saudi Arabia

Using the grain-plate method and on glucose-Czapek's agar at 28°C, fifty-eight species belonging to 26 genera were collected from barley (42 species and 19 genera), maize (29 species and 16 genera), sorghum (32 species and 17 genera) and wheat grains (42 species and 18 genera).The most frequent genera were Aspergillus, Penicillium, Rhizopus, Fusarium, and Mucor followed by Alternaria, Drechslera, and Curvularia. From the preceding genera Aspergillus flavus, A. niger, Penicillium notatum, Rhizopus stolonifer, Fusarium moniliforme, Mucor racemosus, Alternaria alternata, Drechslera spicifera, and Curvularia lunata were the most prevalent species in the four types of grains tested.     

Mycoflora and trichothecene toxins of paddy grains from Egypt

120 species and 38 genera were collected from 64 samples of paddy grains on glucose- and cellulose-Czapek's agar at 28 °C. The total count of glycophilic and cellulose-decomposing fungi fluctuated between 216–29760; and 124–11320 colonies/g paddy grains on the two media, respectively.On glucose agar, the most common species were Aspergillus niger, A. flavus, A. sydowi, A. terreus, A. fumigatus, A. ochraceus, Penicillium chrysogenum, P. corylophilum, Fusarium oxysporum, Alternaria alternata, Cladosporium cladosporioides, Trichoderma viride and Mucor racemosus.On cellulose agar with pH 5.5 & 8.0, the most prevalent fungi were Stachybotrys chartarum, S. bisybi, Aspergillus niger, A. flavus, Fusarium oxysporum, Alternaria alternata, Drechslera sativus and Acremonium strictum.Extracts from 64 paddy samples were tested against brine shrimp larvae (Artemis salina). Of these 9 displayed varying degrees of toxicity. Trichothecene-toxins were detected in the extracts of three paddy samples only. Diacetoxyscirpenol and T-2 toxin were detected in two samples and only T-2 toxin in the other.     

Mycotoxins producing fungi and mycoflora of air-dust from Taif,Saudi Arabia

Using the dilution plate method, 70 species and 31 genera were collected from 20 dust samples on glucose (28 genera and 64 species) and cellulose Czapek's agar (22 genera and 46 species) at 28° C. The most common fungi were Aspergillus niger, A. flavus, A. flavus var. columnaris, Phoma glomerata, Fusarium oxysporum, Penicillium chrysogenum and Mucor racemosus; and A. nidulans, Phoma humicola, Drechslera spicifera and Stachybotrys chartarum on the two media, respectively.Toxicity test showed that about 85% of the isolates tested were toxic to brine shrimp (Artemia salina). Thin layer chromatographic analysis revealed that 13 out of 23 toxic isolates produced known mycotoxins. Toxins identified were: aflatoxins B₁ and B₂, Kojic acid and trichodermine.     

Mycoflora and mycotoxin-producing fungi of air-dust particles from Egypt

Using the dilution-plate method, 27 genera and 64 species were collected from 20 air-dust samples on glucose — (24 genera and 57 species) and cellulose — (21 genera and 45 species) Czapek's agar at 28 °C. There are basic similarities between the mycoflora of air-dust on the two media and the most prevalent species were Aspergillus niger, A. flavus, A. ochraceus, A. terreus, A. versicolor, Penicillium chrysogenum, P. funiculosum, Alternaria alternata, Cladosporium herbarum, Fusarium oxysporum, Rhizopus stolonifer and Trichoderma viride. Chaetomium globosum, Stachybotrys chartarum, Humicola grisea and Arthrobotrys oligospora were common only on cellulose agar plates.Extracts of mycelium from 25 isolates were tested with brine schrimp (Artemia salina); of these 23 displayed varying degrees of toxicity. Thin layer Chromatographic analysis of 12 isolates of Aspergillus flavus revealed that 4 strains were producing detectable aflatoxin. Zearalenone production was noted for 3 out of 5 strains of Fusarium oxysporum and 2 out of 5 strains of F. solani.     

Isolation of endophytic fungi from Cannabis sativa and study their antifungal potential

A systemic study of fungal endophytes associated with different plant parts of Cannabis sativa and their antifungal activity was investigated in the present study. A total of 281 plant segments, including 91 leaves, 93 stem and 97 petioles samples, were screened for the isolation of endophytic fungi. Totally, 212 (77.65%) segments were found colonised by different fungi. Highest colonisation frequency were observed in stem parts (84.94%), then leaves (82.41%) and lowest 59.79% in petiole. Total eight fungal genera belonging to 12 species were isolated. Aspergillus is recorded as the most frequently occurring genera with three species Aspergillus niger, Aspergillus flavus and Aspergillus nidulans followed by Penicillium with two species Penicillium chrysogenum and Penicillium citrinum, while Phoma, Rhizopus, Colletotrichum, Cladosporium and Curvularia with single species. The antifungal potential of A. niger and A. flavus – two most frequently isolated endophytic fungi – was evaluated against two common plant pathogen, Colletotrichum gloeosporioides and Curvularia lunata. Different plant and fungal extracts individually and in combinations showed variations in antifungal activity against both the pathogens. The primary results obtained on antifungal activity of endophytes show their possible role in plant defence mechanism but it is a preliminary approach and more extensive research is still required.     

Cellulase activity of some phytopathogenic fungi isolated from diseased leaves of broad bean

Forty-five fungal species and two varieties belonging to the 23 genera were collected from 50 samples of diseased leaves of broad bean collected from Qena Governorate in Egypt on glucose-Czapek’s, dichloran-chloramphenicol-malt extract and dichloran-chloramphenicol-peptone agar at 28 °C. The most common genera were Alternaria, Aspergillus, Cladosporium, Fusarium, Mycosphaerella and Penicillium. The most prevalent species were Alternaria alternata, Aspergillus flavus, A. fumigatus, A. niger, Cladosporium cladosporioides, Fusarium merismoides, Mycosphaerella tassiana and Penicillium chrysogenum. Among the eight dematiaceous Hyphomycetes phytopathogenic fungi screened for their abilities to produce both exo- and endo-β-1,4-glucanase enzymes (C₁ and C_x), five species had high C₁ enzyme production and two species had high C_x enzyme production. However, two and three species were moderately active in producing C₁ and C_x enzymes, respectively. The remaining species had low production of both C₁ and C_x enzymes. The highest cellulase activity was recorded by Alternaria citri and Cochliobolus spicifer for C₁ and by A alternata and A. citri for C_x enzyme. Maximum production of C₁ enzyme by A. citri and C. spicifer was obtained after six days of incubation at 30 °C with an initial pH of 6 in a culture medium containing lactose and calcium nitrate as the carbon and nitrogen sources, respectively. The highest C_x enzyme production was by A. alternata and A. citri,which was recorded after eight days of incubation at 30 °C with an initial pH of 6 in a culture medium containing carboxymethyl cellulose and sodium or calcium nitrate as the carbon and nitrogen sources, respectively.     

Keratinophilic fungi and other moulds associated with air-dust particles from Egypt

One-hundred and eleven species and three species varieties belonging to 39 genera were collected from 50 dust samples on the five media used at 28°C. Using the hair-baiting technique with horse hair, 10 species ofChrysosporium were isolated:C. asperatum, C. state ofArthroderma tuberculatum, C. indicum, C. inops, C. keratinophilum, C. merdarium, C. pannorum, C. queenslandicum, C. tropicum andC. xerophilum. True dermatophytes were isolated:Trichophyton verrucosum andTrichophyton sp. Also, numerous fungi tolerating high levels of cycloheximide were encountered, such as members ofAcremonium, Aspergillus andPenicillium. On plates of glucose or cellulose Czapek-Dox agar (free from sucrose) the most frequent fungi were:Alternaria alternata, Aspergillus flavus, A. flavus var.columnaris, A. fumigatus, A. niger, A. ochraceus, A. sydowii, A. terreus, Chaetomium globosum, Cladosporium herbarum, Emericella nidulans, Fusarium oxysporum, Mucor hiemalis, Penicillium chrysogenum, P. oxalicum, Scopulariopsis brevicaulis andUlocladium atrum. On plates of 50% sucrose or 10 and 20% NaCl-Czapek's agar, some interesting species were frequently encountered:Eurotium amstelodami, E. chevalieri, E. halophilicum, E. montevidensis, E. repens, E. rubrum andScopulariopsis halophilica. The isolated, fungi have been tested for osmophilicity and halophilicity, they showed different rates of growth on sucrose and sodium chloride-Czapek's medium of various osmotic potential.     

Fungal flora and mycotoxins of six kinds of nut seeds for human consumption in Saudi Arabia

A wide range of moulds representing several genera and species, was recorded in this study from 5 seed samples of each almond, cashew nut, chestnut, hazelnut, pistachio nut and walnut collected from different markets in Ar' Ar, Saudi Arabia. The total counts of fungi were widely fluctuated between 1960–7704 and 1948–7434 colonies/g dry seeds on glucose-Czapek's and glycerol agar media at 28°C, respectively, and represented twenty genera, 53 species and 2 varieties of fungi. The prevalent fungi on the 2 agar media wereAspergillus flavus, A. niger andPenicillium chrysogenum. On glucose-Czapek's agar,Rhizopus stolonifer andAspergillus flavus var.columnaris were isolated from all 6 kinds of nut,A. parasiticus from 5 kinds andA. fumigatus from 4 kinds with high frequencies.Eurotium species were completely absent on glucose-Czapek's agar but they were isolated in high frequency from all kinds of nut on glycerol agar medium. The different nut samples were analyzed by thin layer chromatography for the presence of aflatoxins B₁, B₂, G₁ & G₂, citrinin, ochratoxins, patulin, sterigmatocystin, diacetoxyscirpenol, T-2 toxin and zearalenone. Aflatoxins B₁ & G₁ were detected in 3 out of the 5 samples tested of chestnut at concentrations ranging between 20 to 60 µg/kg. All other samples of almond, cashew nut, hazelnut, pistachio nut, and walnut that were analyzed were mycotoxin free.     

Keratinophilic fungi inhabiting floor dusts of student houses at the South Valley University in Egypt

Keratinophilic fungi include true fungi that vigorously degrade keratin as well as a number of important human pathogenic dermatophytes. We identified 41 species and one variety belonging to 19 genera in 50 floor dust samples following culture on Sabouraud’s dextrose agar medium at 28°C. Dermatophytes and closely related fungi were represented by six species—Aphanoascus fulvescens, Aphanoascus sp., Arthroderma cuniculi, Chrysosporium lucknowense, Gymnoascus uncinatus and Trichophyton rubrum. There were 35 species and one variety of other fungal species, with members of Aspergillus and Penicllium being the most prevalent. Twenty-seven species and 1 variety belonging to 14 genera were identified from 24 dust samples gathered at 2-week intervals from male student housing at El-Kenose during January–December 2005 that had been cultured on Sabauraud’s dextrose agar at 28°C. The monthly counts of keratinophilic fungi showed irregular fluctuations, with a peak in April and the lowest point in November. Dermatophytes and closely related fungi were represented by Aphanoascus fulvescens, Aphanoascus sp., Chrysosporium lucknowense, Gymnoascus uncinatus, and Trichophyton rubrum. In conclusion, the study reports the incidences of some dermatophytes found in the floor dust of student houses of South Valley University, Egypt.     

Rhizosphere and phyllosphere fungi of four fern plants growing in Saudi Arabia

Seventy-eight species in addition to 1 variety of A. flavus belonging to 31 genera were collected from the rhizosphere (55 species + 1 variety and 24 genera) and phyllosphere (59 species and 22 genera) of Adiantum capillus-veneris, Ceterach officinarum, Asplenium filare and Cheilanthes catanensis.In the rhizosphere, the most common genera were Aspergillus, Penicillium, Fusarium, Mucor and yeasts. In the phyllosphere, the most prevalent fungi were Cladosporium herbarum, C. sphaerospermum, Alternaria alternata, Drechslera spicifera, Aspergillus spp., Penicillium spp., Cephalosporium roseo-griseum, Myrothecium verrucaria, Mucor racemosus and yeasts.     

Mycotoxin-producing potential of fungi associated with qat (Catha edulis) leaves in yemen

Forty-four fungal species belonging to 20 genera were isolated from 30 samples of qat leaves. The most frequent genera wereAspergillus, Alternaria, Penicillium, andCladosporium followed byFusarium, Drechslera, Chœtomium, andMucor. The most prevalent species in above genera wereAspergillus niger, A. flavus, A fumigatus, Alternaria alternata, Penicillium chrysogenum, P. citrinum, Cladosporium cladosporioides, andFusarium verticillioides. From these fungi, 17 species (39%) related to 7 genera (35%) proved to be true endophytes. Eleven out of 75 isolates were mycotoxigenic.A. alternata produced alternariol and alternariol monomethyl ether whereasA. flavus produced aflatoxins B₁ and B₂. Ochratoxin A, sterigmatocystin, citrinin and T-2 toxin were produced byA. ochraceus, A. versicolor, P. citrinum andF. oxysporum, respectively. The presence of such toxigenic fungi associated with qat leaves is considered to be a threat to public health.     

Keratinolytic fungi of wadi Qena in Egypt

Forty-six soil samples collected from different sites of wadi Qena were examined for keratinophilic fungi using the hair baiting technique. Thirty-two species in addition to one variety of each ofA. nidulans andA. flavus which belong to eighteen genera were recovered.Aspergillus, Chrysosporium, Penicillium, Microsporum andFusarium were the most frequent genera developed from baited soils.     

Cellulose-decomposing fungi of barley grains in Egypt

100 species and 2 varieties of A. nidulans which belong to 35 genera were identified from 40 samples of barley collected from different places in Upper Egypt. Two methods of isolation were used: the grain-and the dilution plate. The spectrum of fungal genera and species collected by the former (35 genera, 96 species+1 variety) was broader than by the latter method (28 genera, 76 species+1 variety). Nine genera were of high occurrence (represented in more than 50% of the samples) namely, Aspergillus, Penicillium, Fusarium, Alternaria, Chaetomium, Cladosporium, Humicola, Drechslera and Myrothecium. The most frequent species were A. fumigatus, A. niger, A. flavus, A. sydowii, F. oxysporum, F. moniliforme, A. alternata, M. verrucaria, P. funiculosum, P. corylophilum, P. duclauxi, C. herbarum, C. globosum, D. spicifera and H. grisea. Several fungi such as Chaetomium, Humicola, Altemaria, Drechslera, Stachybotrys, Myrothecium, Pénicillium corylophilum and P. funiculosum were far more frequently recovered on cellulose than on glucose agar.     

Bulbs mycoflora and their relation with three stored product mites

The distribution of moulds on stored and field onion and garlic plants infested by bulb mites in Assiut area (Egypt) was studied using PDA medium at 28 °C. Among 40 host samples and the three mite species tested no significant difference was noted in the contamination by moulds. A total of 20 species appertaining to 11 genera were identified from the tested mites and their habitats. The predominant moulds on all samples were “storage moulds” from the genera Aspergillus (A. niger, A. versicolor)and Penicillium (P. chrysogenum, P. funiculosum,and ``field moulds' among which Alternaria, Cladosporium,Fusarium (and its teleomorphs) and Setosphaeria were encountered most frequently. One fungus well known facultative pathogen was obtained: Beauveria bassiana. The tested mites transferA. niger, N. haematococca, R. stolonifer andP. chrysogenum outside their bodies while, A. flavusand A. ochraceus transfer through their digestive tracts along with the foods. Individuals of all mites could survived till the end of the experiment on all fungal species tested except A. niger, A. ochraceus and A. sydowii.Among 48 isolates screened for their ability to produce chitinase, about 83% of the isolates could produce this enzyme. Most of the positive isolates (17 isolates) had moderate producers This revised version was published online in June 2006 with corrections to the Cover Date.     

Aeromycoflora in the Central Milk Dairy of Calcutta, India

Intramural aeromycological survey was performed at the Central Milk Dairy, Calcutta, covering eight locations within the Dairyusing Burkard personal volumetric air sampler. The locations were butter cold storage (−2 °C), cold store (8 °C), packaging section (23 °C), milk processing section (24 °C), reconstituent of skimmed milk (24 °C), quality control lab (25 °C), raw milk reception (28 °C) and loading dock (26 °C). A number of fungal spores, conidia and mycelia were recorded in different rooms: the highest spore quantity was recorded in the packaging section (23 °C) and the minimum at the butter cold store (−2 °C). The dominant spores consisted of Aspergillus niger, A flavus,Cladosporium sp., Fusarium sp., Curvularia sp.,Alternaria sp., Torula sp., Myrotheciumsp., Helminthosporium sp., Periconia sp.,Nigrospora sp. and Pithomyces sp. This revised version was published online in June 2006 with corrections to the Cover Date.     

Distribution of fungi on two mite species and their habitats in Egypt

Fungi associated with two mite species,Acotyledon krameri andTyrophagus putrescentiœ, and their habitats were studied using 1% glucose-Czapek's and potato-dextrose agar media at 28±2°C. A total of 54 species and one variety belonging to 25 genera were recovered from different habitats of mite species; 36 species and one variety belonging to 18 genera were associated with mite bodies. Nearly most fungal species isolated from mite bodies were also encountered in their habitats. The most common species wereAspergillus flavus, A. fumigatus, A. niger, Mucor racemosus, Nectria hœmatococca. A. terreus, Scopulariopsis brevicaulis andTrichurus spiralis were isolated only from mite bodies whereasFusarium oxysporum, Penicillium chrysogenum, P. corylophilum, P. funiculosum andRhizopus stolonifer were recovered from the mite habitats.A. krameri individuals survived well onCunninghamella elegans, F. oxysporum andM. racemosus cultured on both type of media, whereasCylindrocarpon destructans was best forT. putrescentiœ survival.     

Fungal contamination of some imported spices

Seventeen imported raw spice samples obtained from retail outlets were examined for spoilage mould profile. A total of 665 fungal isolates, representing 14 species, were recovered and identified from dried and ground spice samples on several media using standard dilution plate method. Moisture content varied greatly among various samples and were generally high. The most heavily contaminated spice samples examined were observed in red chili and black pepper in order of magnitude of 1580 and 1120 cfu/g, respectively. The most predominant fungal genera encountered were Aspergillus, Penicillium, Rhizopus, Cladosporium and Trichoderma. Yeasts were also frequently recovered, but not identified. Relative occurrence values of taxa disclosed ranged between 36.4% for A. flavus and 0.6% for A. parasiticus and Absidia corymbifera. Samples obtained from gunny bags encounter higher colony counts and contamination frequency than other packing methods. The present magnitude of contamination and spectra of mycobiota approximate those reported for similar spice samples. Although several potentially mycotoxigenic fungi were isolated during the present study, neither the foodstuff nor the fungi were assayed for the presence of these toxins.     

Patulin and aflatoxin in brown rot lesion of apple fruits and their regulation

Aspergillus flavus, A. niger, Penicillium expansum and Rhizopus stolonifer were the most frequently isolated fungi from healthy apple fruits. Alternaria alternata was the most common organism of rotten apple fruits, followed by A. niger, A. flavus, P. expansum and R. stolonifer. The prevalent type of decay, brown rot lesion, is caused by R. stolonifer followed by A. flavus, A. niger, A. alternata and P. expansum. Sodium hypochlorite had good curative properties against fruit rots. The main natural mycotoxins produced in rotten apple were patulin and aflatoxins. The optimum temperature for patulin production by P. expansum was 15 °C after 15 days. Complete inhibition of patulin formation was attained using 0.2% lemon oil and > 90% inhibition using 0.05% lemon and 0.2% orange oils. Also significant inhibition (> 90%) of aflatoxin production was observed with 0.2% lemon oil. This revised version was published online in July 2006 with corrections to the Cover Date.