Colonization ofRetama raetam seeds by fungi and their significance in seed germination

Examination by scanning electron microscopy and incubation on potato-dextrose agar medium showed that dry seeds ofRetama raetam were externally free of fungi. When planted in sandy loam soil, the seeds become colonized with eleven soil-borne fungal species. The fungi were isolated on cellulose agar, pectin agar and lignin agar media.Aspergillus flavus, A. niger, A. fumigatus, Penicillium capsolatum andFusarium oxysporum had broad occurrence and were recovered on all the three media. The production of hydrolytic enzymes by the isolated fungi depends on the substrate and species.Penicillium capsolatum, P. spinulosum andA. niger had wide enzymatic amplitude and they were able to produce cellulolytic, pectolytic and lignolytic activities on corresponding substrates as well as on seed-coat-containing media. The lignolytic activities of the isolated species exceptChaetomium bostrychodes andTrichoderma viride were enhanced by applying the seed-coat materials as C- source rather than lignin. SoakingR. raetam seeds in culture filtrates of most of the fungi grown on seed-coat-supplemented media induced a pronounced and distinct stimulating effect on seed germination. The most effective filtrates were those ofP. capsolatum, P. spinulosum andSporotrichum pulverulentum.     

Studies on mycoflora of salt marshes in Egypt. IV=osmophilic fungi

Ninety-five species and seven varieties which belong to thirty-nine genera were isolated from 74 soil samples from salt marshes. At 28°C, on 30% sucrose Czapek's agar, ninety species and four varieties which belong to thirty-six genera were encountered, from which A. niger, A. fumigatus A. terreus and P. notatum were the most frequent. On 60% sucrose Czapek's agar, sixty-three species and three varieties were recovered which belong to twenty-five genera, from which A. niger, A. fumigatus, Cladosporium herbarum and A. terreus were the most frequent.At 45°C, on 30% sucrose, sixteen species and four varieties were identified, but on 60% sucrose, fourteen species and three varieties were isolated. A. fumigatus and A. niger were the most frequent on both sucrose concentrations.The results reveal that the soil samples poor in total osmophilic fungi (at 28°C) were significantly higher in their content of total soluble salts, Na and K and significantly lower in the average number of species per soil samples than the rich ones; the difference was nonsignificant in case of organic matter.     

Keratinophilic and other fungi isolated from combine harvester wheat and sorghum dusts and from the atmosphere of winnow sites in egypt

Three methods were used for the isolation of fungi in the present investigation: the dilution-plate method, hair-baiting technique with horse hairs and the “exposed plate” method. Sabouraud's glucose agar at 28 °C was also used as isolation medium. 102 species and 2 species varieties belonging to 36 genera were collected from combine harvester wheat and sorghum dusts and from the atmosphere of hay or winnow sites.Chrysosporium was represented by 6 species:C. asperatum, C. indicum, C. keratinophilum, C. merdarium, C. pannorum andC. tropicum. Several filamentous fungi tolerating high levels of cycloheximide and other moulds were frequently encountered in the two types of dusts and in the two atmospheres, such as members ofAcremonium, Alternaria, Aspergillus, Cladosporium, Emericella, Eupenicillium, Fusarium, Paecilomyces, Penicillium, Piedraia, Rhizopus, Scopulariopsis and others.     

Utilization of oligosaccharides by three imperfect fungi

Summary The utilization of oligosaccharides (maltose, sucrose, lactose and raffinose) by three imperfect fungi viz.Alternaria tenuis Auct.,Colletotrichum capsici (Syd.)Butler &Bisby andColletotrichum gloeosporioides Penz. isolated from diseased leaves of tomato,Scindapsus pictus andPolyscias balfuriana respectively, was studied chromatographically. Except for lactose, all the sugars were utilizzed through a hydrolytic pathway and almost all proved to be a suitable source of carbon for the growth of fungi. Along with the utilization of sucrose, a simultaneous synthesis of an oligosaccharide was also observed in case of two species ofColletotrichum. C. gloeosporioides, however, also synthesized an oligosaccharide, maltotriose if it is grown in the medium containing maltose. During the utilization of raffinose, melibiose and fructose were detectted in the culture medium ofA. tenuis. Melibiose was further broken down into glucose and galactose by the two species ofColletotrichum.All the sugars were consumed from the media within 15 days except for lactose which persisted in the media even after 15 days.     

Fungi associated with the aerial parts of Malaysian mangrove plants

The leaf surface fungi associated with nine species of mangrove plants includingAvicennia alba, A. officinalis, Bruguiera parviflora, Ceriops tagal, Rhizophora apiculata, R. mucronata, Sesuvium portulacastrum, Sonneratia alba, andXylocarpus mollucensis were studied using direct observation techniques and leaf washings. Over 40 fungal taxa were isolated from the leaf washings. Of these, species ofAspergillus, Choanephora, Cladosporium, Curvularia, Fusarium, Nigrospora, Penicillium, Pestalotiopsis, Trichoderma, andZygosporium were frequently encountered in the washings of all nine mangrove plants. Fewer species of fungi includingCladosporium oxysporum, Corynespora cassiicola, Fusarium, Penicillium, Pestalotiopsis, andZygosporium were capable of growth on the washed leaves. The major phylloplane fungus on plants with higher leaf tannin content (e.g.B. parviflora, C. tagal, Rhizophora spp., andX. mollucensis) wasPestalotiopsis. Leaves with relatively lower amounts of tannin supported the proliferation ofFusarium as the major fungus. Fungi were present on the plumule and cotyledonous sheath even before the leaves opened.Pestalotiopsis persisted throughout the development and growth of the leaves. Many of the fungi encountered on senescent leaves have been reported in earlier studies to be the primary colonisers of submerged decaying leaves.     

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.     

Isolation of fluconazole-tolerant micromycetes onto different cultivation media

On studying the dependence of quality and/or quantity of environmental fluconazole-tolerant micromycetes on culture mediumin vitro, the highest number of isolates was obtained in Sabouraud agar (SA) without fluconazole (59 CFU/mg of soil sample at 25°C and 31 CFU/mg at 37°C). In the case of SA, fluconazole inhibited the growth of micromycetes to 83%. Significant differences were found between the average concentration of CFU/mg for six cultivation media without and with fluconazole (70 mg/L) at 25 and 37°C. The genusAspergillus (A. flavus, A. fumigatus, aspergilli fromA. glaucus andA. niger group,A. nidulans, A. versicolor, A. ustus), Scopulariopsis brevicaulis andPenicillium sp. were the most common isolates. Sabouraud agar combined with malt extract agar, dichloran-18% glycerol agar and potato-dextrose agar were the most suitable for isolation of fluconazole-tolerant fungi.     

Fibrinolytic activity of some fungi isolated from self-heated composted fertilizer

Mesophilic fungi isolated from organic fertilizer compost samples accounted for 70.94% of the total fungal count, while thermophilic and thermotolerant fungi constituted 29.05% of that count. Eight mesophilic fungal species, namelyAspergillus niger, Monilia sitophila, Paecilomyces divaricata, Penicillium chrysogenum, P. fellutanum, Scopulariopsis brevicaulis, S. brumptii andZygorhynchus japonicus; two thermophilic fungiHumicola grisea andOidiodendron flavum and three thermotolerant speciesAspergillus fumigatus, Thermomyces lanuginosus andZygorhynchus vuilleminii were isolated during the study. Most of the tested fungi showed a proteolytic activity and liquified gelatin in the test tube method and in cup plates. The thermophilic fungusO. flavum was the most potent proteolytic fungus. The comparative fibrinolytic assay revealed the following sequence in the ability of the tested fungi to hydrolyse fibrin:O. fiavum>S. brevicaulis>H. grisea>A. fumigatus>T. lanuginosus.     

Detection of 3-nitropropionic acid and cytotoxicity inMucor circinelloides

Mucorales are regarded as the aetiological agents of Mucormycosis. Their capabilities to produce mycotoxins are not profoundly investigated, in contrast to those of the fungi from the generaPenicillium, Aspergillus, orFusarium. The aim of this study was to isolate and identify fungi of the order Mucorales and investigate mycotoxins production. Twelve samples of visibly moulded grass silage and eight samples of damaged whole crop maize silage were analysed. Malt extract agar plates were used for sub cultivation. Three fungal species of the order Mucorales were isolated from grass silage, which were identified by their macro-and micro-morphology asAbsidia corymbifera, Mucor circinelloides andRhizopus stolonifer. The cytotoxicity ofMucor circinelloides extract was analysed using the cytotoxicity test (MTT assay) and the result, showed a low cytotoxicity. Additionally extracts fromAbsidia corymbifera, Mucor circinelloides andRhizopus stolonifer were tested for mycotoxin-production using an LC/MS/MS-based multimycotoxin method. 3-nitropropionic acid was detected in the culture extract ofMucor circinelloides. Presented at the 30^th Mykotoxin Workshop Utrecht, Netherlands, April 28–30, 2008.     

Taxonomic studies on new or critical fungi of non-pathogenic onygenales 3

Two new species of soil-borne onygenalean fungi are described and illustrated:Arachniotus insolitus, isolated from forest soil in Kenya, andMyxotrichum stellatum, isolated from forest soil in Japan. A further occurrence ofGymnoascus uncinatus, isolated from Canadian soil, is reported and some observations are added, especially in connection with the cultural appearance of this rarely encountered species.     

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.     

Studies on the methylation of mercuric chloride by pure cultures of bacteria and fungi

Small amounts of methylmercury were produced during 7 days aerobic growth in the presence of sublethal amounts of mercuric chloride by the following bacterial species studied:Pseudomonas fluorescens, Mycobacterium phlei, Escherichia coli, Aerobacter aerogenes, Bacillus megaterium. Under the same conditions methylmercury was also formed by mycelium of the fungi investigated:Aspergillus niger, Scopulariopsis brevicaulis andSaccharomyces cerevisiae. The concentration of the methylmercury produced by the various organisms did not vary much and was of the same order of magnitude as that found in Swedish experiments with lake sediments. In bacteria most of the methylmercury formed was present in the culture liquid, whereas the remainder was in or on the cells. In contrast, methylmercury formed by fungi was for the greater part present in the mycelium. The production of methylmercury byE. coli andA. aerogenes was lower under anaerobic conditions than under aerobic conditions.     

Antagonistic interactions between fungal pathogens and phylloplane fungi of guava

Dominant phylloplane fungi of guava (Psidium guajava L.) were screened for their antagonistic activities against the two pathogens,Colletotrichum gloeosporioides andPestalotia psidii, bothin vitro andin vivo. Culture filtrates ofAspergillus niger, Fusarium oxysporum andPenicillium citrinum caused more than 50% growth inhibition ofC. gloeosporioides. Filtrates ofCephalosporium roseo-griseum andF. oxysporum were most effective in reducing the growth ofP. psidii. Volatiles produced from the cultures ofA. niger, F. oxysporum, P. citrinum andP. oxalicum inhibited the growth ofC. gloeosporioides, whereas volatiles fromC. roseo-griseum, F. oxysporum andTrichoderma harzianum inhibited the growth ofP. psidii. The inhibitory effect of volatiles decreased with increase in incubation time. In general, the maximum effect of volatiles was noticed after 48 h incubation. Different grades of colony interactions in dual cultures were recognised between the two pathogens and the phylloplane fungi examined. Maximum inhibition ofC. gloeosporioides was caused byAureobasidium pullulans, Cladosporium cladosporioides, epicoccum purpurascens, F. oxysporum andMyrothecium roridum, whereasAspergillus terreus, C. roseo-griseum andP. oxalicum significantly reduced the growth ofP. psidii. Application of a spore suspension of each test fungus inhibited lesion development of guava leaves caused by the test pathogensin vitro. Inhibition was more pronounced when the spore concentration was increased.A. pullulans, C. cladosporioides, E. purpurascens, F. oxysporum, andT. harzianum were found to be strongly antagonistic toC. gloeosporioides. A. niger, A. terreus, C. roseo-grisem andT. harzianum were strongly antagonistic toP. psidii.     

Studies on the distribution of alkalophilic and alkali-tolerant soil fungi I

Soil fungi were isolated from two different soil types using alkaline and slightly acidic media (alkaline cornmeal agar (AC-MA), pH 9.7; cornmeal agar (CMA), pH 6.0) to study their distribution. Different species were obtained on each isolation medium. The number of species ofAcremonium andFusarium increased on ACMA, though many species growing well in acidic conditions were not detected on ACMA. Most of the fungi isolated on ACMA, especially from the alkaline soils, were alkalophiles or alkali-tolerants that can grow at pH 10.Acremonium alternatum, A. furcatum, Acremonium sp. 6,Gliocladium cibotii (YBLF 575),Phialophora geniculata, Stachylidium bicolor andStilbella annulata were alkalophilic, of whichAcremonium sp. 6 was the most pronounced alkalophile. Ability to grow under alkaline conditions, as well as under acidic conditions, was common in manyAcremonium species. The use of alkaline medium facilitates the isolation of alkalophilic soil fungi.     

Ubiquinone system,GC contents and cellular fatty acid composition of species of the form-genusMalbranchea andCoccidioides immitis for chemotaxonomic study

Ubiquinone system, GC contents and cellular fatty acid (CFA) composition were analyzed as criteria for chemotaxonomy ofMalbranchea species andCoccidioides immitis, which are suggested to be phylogenetically related. Based on the major ubiquinone,Malbranchea spp. were divided into two groups, of which one group possessed the same major ubiquinone asC. immitis. Similar GC contents and CFA profiles were obtained for the species ofMalbranchea andC. immitis. On the basis of these criteria the relationships between the fungi are discussed.     

Mycoflora of birds' nests in nest-boxes

A mycoflora has been investigated in 57 nests of 8 free-living birds' species, placed in nest boxes, on 3 localities in Czechoslovakia. The nests have been shown to be densely inhabited by fungi: 476 isolates ofPhycomycetes, Ascomycetes and Fungi Imperfecti have been recorded, the mean number being 8.4 species in a nest. Keratinolytic fungi have been found in 92.8 % of nests, with the most commonly isolated speciesArthroderma ciferrii, Anixiopsis stercoraria, Chrysosporium keratinophilum, C. tropicum, Ctenomyces serratus, Arthroderma tuberculatum, A. quadrifidum andA. curreyi. From present studies results that birds' nests placed in holes or in boxes supposing they are lined with keratinous material could probably be the dominant habitat ofA. ciferrii (stat. con. =Trichophyton georgiae). Cellulolytic fungi have been found in 87.7 % of the nests, most often species of the generaFusarium, Chaetomium, Alternaria, Phoma andCladosporium. Further, fungi potentially zoopathogenic have been isolated (73.7 % of nests and 13.9 % of all isolates), e.g.,Absidia lichtheimii, Aspergillus amstelodami, A. flavus, A. fumigatus, A. nidulans, A. niger, Candida albicans, C. tropicalis, Microsporon cookei andTrichophyton ajelloi. In many cases have also been ascertained fungi causing sooty mildews of various plants (Alternaria alternata, Aureobasidium pullulans, Cladosporium spp.).As factors influencing both qualitative and quantitative composition of the mycoflora in the nests have been established: composition of lining material, its humidity and pH, birds' species, fledging, repeating nesting in a box, and locality.In keratinolytic fungi, the highest competitive saprophytic ability on a given substrate have revealedC. keratinophilum, A. stercoraria, A. ciferrii andC. tropicum, while the lowest oneA. quadrifidum andA. cuniculi.     

Fungi from Alberta rodents

Summary The occurrence, by years, ofE. parva in Alberta rodents is presented in tabular form covering the period 1946 to 1959. The infection rate was 5.1.% in 1946, 3.3% in 1957 and less than 1% thereafter.It was found that the lungs of Alberta rodents have a characteristic mold flora comprised chiefly of:Penicillium spp., Beauveria bassiana, Aspergillus spp. and perhapsScopulariopsis brevicaule, Cladosporium spp. andChrysosporium pannorum. Trichophyton mentagrophytes and anotherTrichophyton were isolated from the livers, spleens or lungs of six rodents. Phycomyces blakesleeanus was isolated from the lungs of two rodents trapped in northern Alberta.     

Low occurrence of patulin‐ and citrinin‐producing species isolated from grapes

Aims: To assess the ability of fungi isolated from grapes to produce patulin and citrinin. Methods and Results: A total of 446 Aspergillus isolates belonging to 20 species and 101 Penicillium isolates were inoculated in Czapek yeast extract agar and yeast extract sucrose agar and incubated for 7 days at 25°C. Extracts were analysed for patulin and citrinin by thin‐layer chromatography. None of the isolates of Aspergillus spp. produced either patulin or citrinin. Patulin was produced by three isolates of Penicillium expansum and two of Penicillium griseofulvum. Citrinin was produced by five isolates of P. expansum, two of Penicillium citrinum and one of Penicillium verrucosum. Conclusions: Our results show that the Aspergillus and Penicillium species commonly isolated from grapes are not a source of the mycotoxins, patulin and citrinin. Significance and Impact of the Study: The possibility of co‐occurrence of patulin and citrinin with ochratoxin A in grapes and grape products remain low, owing to the low frequency of isolation of potentially producing species.     

Fungi associated with the aerial parts of Malaysian mangrove plants

The leaf surface fungi associated with nine species of mangrove plants includingAvicennia alba, A. officinalis, Bruguiera parviflora, Ceriops tagal, Rhizophora apiculata, R. mucronata, Sesuvium portulacastrum, Sonneratia alba, andXylocarpus mollucensis were studied using direct observation techniques and leaf washings. Over 40 fungal taxa were isolated from the leaf washings. Of these, species ofAspergillus, Choanephora, Cladosporium, Curvularia, Fusarium, Nigrospora, Penicillium, Pestalotiopsis, Trichoderma, andZygosporium were frequently encountered in the washings of all nine mangrove plants. Fewer species of fungi includingCladosporium oxysporum, Corynespora cassiicola, Fusarium, Penicillium, Pestalotiopsis, andZygosporium were capable of growth on the washed leaves. The major phylloplane fungus on plants with higher leaf tannin content (e.g.B. parviflora, C. tagal, Rhizophora spp., andX. mollucensis) wasPestalotiopsis. Leaves with relatively lower amounts of tannin supported the proliferation ofFusarium as the major fungus. Fungi were present on the plumule and cotyledonous sheath even before the leaves opened.Pestalotiopsis persisted throughout the development and growth of the leaves. Many of the fungi encountered on senescent leaves have been reported in earlier studies to be the primary colonisers of submerged decaying leaves.     

Serratia species isolated from plants

Using the selective caprylate-thallous agar medium, the presence ofSerratia species was systematically examined in 623 plant samples. A total of 167Serratia strains was isolated from these plant samples and identified to species and biogroups. Uniform and characteristicSerratia populations were found in figs and coconuts: (i)Serratia ficaria was recovered from most figs collected in California, Tunisia, and France; various biotypes ofS. marcescens also were found in figs; (ii) onlyS. marinorubra was recovered from coconuts bought on two continents. From plants other than figs and coconuts, representatives were isolated of all eightSerratia species we presently recognize—with a large preponderance ofS. liquefaciens andS. proteamaculans. These other plant samples fell into threeSerratia-prevalence groups: (i) vegetables-mushrooms-mosses-decaying plant material (53.8% of these samples were positive forSerratia); (ii) grasses (23.7% positive); and (iii) trees and shrubs-small plants (8.4% positive). PigmentedS. marcescens biotypes were rarely isolated from plants (except from figs). Of theS. marcescens biogroups most frequently encountered in nosocomial and iatrogenic infections of man, A3 and A4 were isolated from plants in this study, but A5/8 and TCT were not.