Toxigenic fungi isolated from roquefort cheese

To evaluate the potential for mycotoxin production by fungi contaminating blue-veined cheese, as well as by the ripening fungus,Penicillium roqueforti, the fungal flora of six of local and imported brands was determined. A total of 19 fungi were isolated from the six brands tested. Fourteen of the isolates were toxic to chicken embryos. The toxigenic fungi produced the following mycotoxins:Aspergillus fumigatus, kojic acid;A. versicolor, sterigmatocystin;Penicillium roqueforti, penicillic acid and unidentified toxic metabolites.     

Molecular characterization of fungal endophytes from Calotropis procera plants in Taif region (Saudi Arabia) and their antifungal activities

Fungal endophytes were isolated from the leaves of Calotropis procera (Apocynaceae) collected from Taif region (Saudi Arabia). Thirty-three different taxa were recovered. The overall foliar colonization rate was 35.1%. A total of 161 isolates were obtained and identified into 33 distinct operational taxonomic units based on the sequencing of the internal transcribed spacer regions of the rRNA gene. The most prevalent fungi were Aspergillus flavus, Chaetomium globosum, Cochliobolus lunatus, Fusarium dimerum, F. oxysporum, and Penicillium chrysogenum. A total of 161 isolates were tested for antifungal activities against four plant pathogenic fungi (Alternaria alternata, Fusarium oxysporum, Botrytis cinerea, and Pythium ultimum), of which 33 isolates showed antifungal activity against at least one plant pathogenic fungi. Four isolates of Chaetomium globosum and three isolates of Myrothecium verrucaria showed the strongest antifungal activity. This study reported the occurrence of a much wider spectrum of fungi, when compared with previous work. Also, it confirmed the variation of different isolates from the same species in terms of antifungal activity.     

Biodegradation of plant wastes to sugars and protein by microorganisms

Inoculation of different plant wastes with microorganisms resulted in a release of maximum reducing sugars (33%) from sugar-cane leaves when subjected toPenicillium oxalicum. Maximum protein was formed from sugar-cane bagasse inoculated withAspergillus fumigatus. Association of sugar-cane leaves withP. oxalicum showed the highest digestibility. The use of such microorganisms may help to provide additional and valuable proteins ultimately for human use.     

Effect of Sparkill and Tafaban insecticides on the mycoflora of maize plant in Upper Egypt

Sparkill (25% Cypermethrin) and Tafaban (48% Chlorpyrifos) insecticides were used in the treatment of maize plants in the field to investigate the effect of these compounds on fungi associated with roots and shoots of maize as well as on soil fungi. Generally, the two insecticides exhibited an inhibitive effect on the total and individual counts of glucophilic fungi after different periods of treatment except in some cases the counts were not affected or promoted compared with the control samples. Fungal genera and species associated with roots and shoots of maize plants were isolated from untreated plants as control and then compared with those isolated from plants treated with different doses of insecticides. The most common fungal species recovered from soil and different parts of plants were Alternaria alternata, Aspergillus flavus, A. fumigatus, A. niger, A. terreus, Cochliobolus spicifer, Emericella nidulans, E. nidulans var. lata, Fusarium oxysporum, Gibberella fujikuroi, Nectria haematococca, Penicillium chrysogenum, P. funiculosum, P. oxalicum and Rhizopus stolonifer.     

Studies on the mycoflora associated with sugarcane factory waste and pollution of River Nile in upper Egypt

Sixty-nine species and four varieties that belong to 28 genera of terrestial fungi were recovered from polluted and non-polluted water and mud samples on glucose and cellulose-Czapek's agar at 28°C. The most common species from the two substrates on the two types of media were Aspergillus flavus, A. fumigatus, A.niger, Cladosporium cladosporioides, Fusarium oxysporum, Mycosphaerella tassiana and Penicillium chrysogenum. Twenty-six species belonging to 14 genera were isolated from polluted (26 species and 14 genera) and non-polluted (17species and 10 genera) mud samples on Sabouraud's dextrose agar at 28°C. The most prevalent species were Acremonium retiulum, Alternaria alternata, Aspergillus flavus, Aphanoascus fulvescens, A. terreus, Aphanoascus sp., Penicillium funiculosum and Stachybotrys chartarum.     

Antimicrobial Activity and Biodiversity of Endophytic Fungi in <Emphasis Type="Italic">Dendrobium</Emphasis><Emphasis Type="Italic">devonianum</Emphasis> and <Emphasis Type="Italic">Dendrobium thyrsiflorum</Emphasis> from Vietman

Endophytic fungi are rich in orchids and have great impacts on their host plants. 53 endophytes (30 isolates from Dendrobium devonianum and 23 endophytic fungi from D. thyrsiflorum) were isolated, respectively, from roots and stems of Dendrobium species. All the fungi were identified by way of morphological and/or molecular biological methods. 30 endophytic fungi in D. devonianum were categorized into 11 taxa and 23 fungal endophytes in D. thyrsiflorum were grouped into 11 genera, respectively. Fusarium was the dominant species of the two Dendrobium species in common. Antimicrobial activity of ethanol extract of fermentation broth of these fungi was explored using agar diffusion test. 10 endophytic fungi in D. devonianum and 11 in D. thyrsiflorum exhibited antimicrobial activity against at least one pathogenic bacterium or fungus among 6 pathogenic microbes (Escherichia coli, Bacillus subtilis, Staphylococcus aureus, Candida albicans, Cryptococcus neoformans, and Aspergillus fumigatus). Out of the fungal endophytes isolated from D. devonianum and D. thyrsiflorum, Phoma displayed strong inhibitory activity (inhibition zones in diameter >20 mm) against pathogens. Epicoccum nigrum from D. thyrsiflorum exhibited antibacterial activity even stronger than ampicillin sodium. Fusarium isolated from the two Dendrobium species was effective against the pathogenic bacterial as well as fungal pathogens. The study reinforced the assumption that endophytic fungi isolated from different Dendrobium species could be of potential antibacterial or antifungal resource.     

Role of opportunistic fungi in ocular infections in Nigeria

The importance of opportunistic fungal pathogens in causing ocular infections is emphasized. A study was conducted over a period of 4 years (1974–1977) to investigate the role of opportunistic fungi in causing mycotic keratitis and to elucidate certain aspects of epidemiology of this disease in Nigeria. Fifty-nine cases of corneal ulcers of suspected mycotic etiology were investigated. Fungal etiology was confirmed in 42 of these cases. The predominant etiological agent was Fusarium solani in 14 cases (33.33%) followed by Penicillium citrinum in 8 cases (19.04%) and Aspergillus fumigatus in 5 cases (11.90%). The yeasts were responsible for only 3 cases (7.14%) i.e. one each caused by Candida albicans, C. parapsilosis and C. guilliermondii. Among the remaining 12 cases, one was caused by F. moniliforme, 3 by A. flavus, 2 each by A. niger, Penicillium expansum and Penicillium sp., and one each by Cladosporium cladosporioides and Cladosporium sp. The clinical features of the cases are briefly described.The incidence of mycotic keratitis in relation to sex, age, occupation, trauma and other factors has been analysed. Corneal trauma appeared to be an important predisposing factor as 27 (67.28%) of the patients gave a history of injuries to the eye. Notably, a large number of patients were farmers and trauma was most often from palm tree leaf, thorn, kernel or other plant objects. Topical application of corticosteroids or broad spectrum antibiotics did not seem to play an important role in the etiology of keratomycosis. Cases were recorded throughout the year although the number of cases was higher in the months of March –May, and November–December than that during the rest of the year.The isolates of the causative agents were studied in detail for their morphological and cultural characters. The isolates of F. solani grew well at 37°C and survived at 40°C for more than 3 weeks. In vitro drug sensitivity tests indicated good antifungal activity of pimaricin and econazole for F. solani, clotrimazole and econazole for Aspergillus fumigatus, A. flavus and Penicillium citrinum, and 5-fluorocytosine for Candida spp.Investigations on the incidence of fungi in normal healthy eyes of 450 persons comprising 204 adults and 246 children yielded 204 isolates belonging to 21 genera of fungi. Cladosporium was most frequent (12.88%) followed by Penicillium (10.22%) and Aspergillus (6.66%). Another important fungus was Fusarium represented by 10 isolates, viz. 4 of F. solani, 2 of F. moniliforme, 1 of F. exysporum, and 3 of Fusarium sp. The yeasts were represented by two isolates each of Candida tropicalis, C. pseudotropicalis, C. krusei, Trichosporon sp and Cryptococcus albidus, and one of Candida guilliermondii. Successive culturing of fungi from normal eyes in a small group indicated that fungi occur in the outer eye generally as transients.The epidemiology of mycotic keratitis has been discussed in relation to the present findings and in comparison with observations of other investigators.     

The Diversity and Antimicrobial Activity of Preussia sp. Endophytes Isolated from Australian Dry Rainforests

Limited knowledge currently exists regarding species diversity and antimicrobial activity of endophytic isolates of Preussia within Australia. This report describes endophytic Preussia species that were identified through molecular analysis of the internal transcribed spacer region. Screening for antimicrobial secondary metabolites was determined by testing crude ethyl acetate (EtOAc) extracts derived from fungal mycelia against a panel of ATCC type strains which included Bacillus cereus, Escherichia coli, Enterococcus faecalis, Pseudomonas aeruginosa, Serratia marcescens, methicillin-resistant Staphylococcus aureus (MRSA) and the opportunist yeast pathogen Candida albicans. Subsequently, high-performance liquid chromatography generated fractions of bioactive EtOAc extracts which were subject to confirmatory testing using the Clinical and Laboratory Standards Institute reference microdilution antimicrobial activity assay. A total of 18 Preussia were isolated from nine host plants with 6/18 having a <97 % sequence similarity to other known species in Genbank, suggesting that they are new species. In preliminary screening, 13/18 Preussia isolates revealed antimicrobial activity against at least one of the microbes tested, whilst 6/18 isolates, including 4/6 putative new species showed specific antimicrobial activity against MRSA and C. albicans. These results highlight the antimicrobial potential of Australian Preussia spp. and also the importance of Australian dry rainforests as an untapped repository of potentially significant bioactive compounds.     

中国南海部分深海沉积物真菌多样性及其抗菌活性

【目的】从南海4个站位的深海沉积物中分离真菌,揭示其多样性并测定抗菌活性。【方法】使用4种培养方法和8种培养基,从12个深海沉积物样本中分离培养真菌,通过菌落形态观察和ITS序列系统发育分析进行鉴定。采用滤纸片扩散法和生长速率法分别测试真菌小量发酵液粗浸膏的抗细菌和抗真菌活性。【结果】共分离到125株纯培养真菌,基于形态和ITS序列分析,排重后得到18个种类型,这些真菌可以划分到12个属,大多数属于子囊菌门(Ascomycota),只有2株属于担子菌门(Basidiomycota)。4个站位可培养真菌多样性具有差异性。抑菌活性筛选显示,大多数真菌具有较好的抑菌活性;链格孢属(Alternaria)、青霉属(Penicillium)、匐柄霉属(Stemphylium)这几个属的真菌表现出对多种指示细菌有抑制作用,尤其是Alternaria tenuissima DN09、Alternaria alternata DN14和Penicillium chrysogenum DN16对G~+和G~–细菌均表现出抑制作用。【结论】本研究揭示了南海深海沉积物可培养真菌多样性和抑菌活性,为进一步利用深海沉积物来源真菌奠定了基础。     

Effect of Kocide and Ridomil plus fungicides on the mycoflora of tomato plant in Upper Egypt

Kocide 101 (77% cupric hydroxide) and Ridomil plus (15% metalaxyl and 35% copper oxychloride) were used in the treatment of tomato plants in the field. Generally, the two fungicides exhibited an inhibitive effect on the total and individual counts of glucophilic fungi after different periods of treatment except in some cases, the counts were not affected or promoted compared with the control. Fungal genera and species associated with roots and shoots of tomato plants were isolated from untreated plants as control and then compared with those isolated from plants treated with different doses of fungicides. The most common fungal species recovered from soil and different parts of plants were Alternaria alternata, Aspergillus flavus, A. fumigatus, A. niger, A. terreus, Cochliobolus spicifer, Emericella nidulans, E. nidulans var. lata, Fusarium oxysporum, Gibberella fujikuroi, Mycosphaerella tassiana, Nectria haematococca, Penicillium chrysogenum, P. funiculosum, P. oxalicum, Stachybotrys chartarum and Rhizopus stolonifer.     

Incidence of allergenically significant fungal aerosol in a rural bakery of West Bengal,India

The frequency of fungal spores in the air of three different sections of a rural bakery was analyzed using a Burkard personal slide sampler and Andersen two stage viable sampler. In average concentration of spores (No./m³) was 228–26770/m³ and concentration of viable colony forming units (CFU/m³) was 65-2061 CFU/m³. Dominant fungus species both culturable and nonculturable, were species of Aspergillus and Penicillium, Cladosporiumsp., Aspergillus niger, Aspergillus flavus, Aspergillus fumigatus, Cladosporium cladosporioides, Penicillium citrinum and Alternaria alternata. Seasonal variations in the spore concentrations were clearly observed in case of some fungi. Total culturable mould concentration of different bakery sections sometimes exceeded the acceptable limit for a healthy indoor environment. Antigenic extracts prepared from some dominant culturable fungi showed high level of allergenicity in skin prick tests indicating that they could be responsible for allergic respiratory dysfunction of bakery workers.This revised version was published online in October 2005 with corrections to the Cover Date.     

Fungal endophytes from leaves of Avicennia marina growing in semi-arid environment as a promising source for bioactive compounds

Endophytic fungi are broadly dispersed residing inside plant tissues and have been demonstrated as a treasure for bioactive natural products. Unexplored harsh and heavy metal contaminant habitat of Avicennia marina may have diverse and potential fungal association. Therefore, this work aimed to isolate the culturable fungal endophytes associated with leaves of A. marina and to evaluate their medical potentialities. Seventeen isolates of endophyte fungi were isolated from healthy leaves and their antimicrobial activities were evaluated. Results showed that isolates had activity against micro-organisms in addition to their antioxidant activity produced a variety of phenolic compounds, besides exhibited a lowest cytotoxicity against ATCC-CCL-81 cell line. Consequently, selected endophytic fungal isolates were identified genetically as Chaetomium sp., Chaetomium madrasense, Chaetomium sp., Chaetomium globosum, Aspergillus hiratsukae, Aspergillus ochraceus, Alternaria tenuissima and Curvularia lunata with gene bank accession numbers MT089951, MT089952, MT089953, MT089954, MT089955, MT089956, MT089957 and MT089958 respectively. The most potent fungus extract was analysed using Gas chromatography–mass spectrometry which verified the presence of numerous bioactive compounds. These findings confirmed that new endophytic fungal strains derived from A. marina thrive in harsh ecosystem produce bioactive metabolites which can be recommended as a novel source for drug discovery.     

Diversity and exploration of bioactive marine actinomycetes in the Bay of Bengal of the Puducherry coast of India

The present study was designed to investigate the Puducherry coast of the Bay of Bengal, India for the diversity of bioactive actinomycetes. A total of 50 actinomycete strains were isolated from the marine sediments and most of the strains were belongs to Streptomyces. These strains were identified by means of morphological physiological, biochemical and cultural characteristics. The isolates were subjected to shake flask fermentation and the secondary metabolites were extracted with ethyl acetate and screened for cytotoxicity, hemolytic activity and antimicrobial activity against selected bacterial and fungal pathogens. The cytotoxic activity was evaluated using HeLa cell lines by 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, a tetrazole (MTT) assay, hemolytic activity on mouse erythrocytes and the antifungal activity was evaluated by MTT cytotoxic assay against Aspergillus niger, Aspergillus fumigatus and Candida albicans. The antibacterial activity was studied against Staphylococcus aureus, Bacillus subtilis, Escherichia coli and Klebsiella pneumoniae. The cytotoxicity and antimicrobial activity of secondary metabolite was found to be concentration dependent and nearly 24% of isolates showed significant antimicrobial, hemolytic and cytotoxic activity. The results of our study indicate the diversity and bioactive potential of marine actinomycetes isolated in the Puducherry coast.     

Bio-protective potential of lactic acid bacteria isolated from fermented wax gourd

The antifungal activities of 85 lactic acid bacteria strains isolated from fermented wax gourd against the four fungal species, Penicillium oxalicum, Aspergillus flavus, Aspergillus sydowii, and Mucor racemosus, were determined. Inhibitory activity against at least one or more fungal species was observed with 27 Weissella cibaria and 11 Weissella paramesenteroides strains. Among these strains, W. cibaria 861006 and W. paramesenteroides 860509 showed greater inhibitory activities and were therefore selected for further analysis. The results suggested that the antifungal activities were originated from the organic acids produced by W. cibaria 861006 and W. paramesenteroides 860509. The application tests indicated that the growth of P. oxalicum could be effectively inhibited by W. cibaria 861006 for 6 days on grape surfaces. However, W. paramesenteroides 860509 could only remain its inhibition effect for 48 h. The findings obtained in this study suggest the potential use of W. cibaria 861006 as a bio-protective agent against fungi for agricultural purposes or ready-to-eat fresh fruit and vegetable products.     

Colonization capacity of the soil micro-organisms in relation to fungistasis

Summary Evans' tube and cellophane agar-disc techniques were used to evaluate the colonization capacity of the soil microbes and fungistasis, respectively. Spore germination ofAlternaria tenuis, Curvularia geniculata, Helminthosporium rostratum andPestalotia sp. was studied on a natural soil. Aspergillus fumigatus was the pioneer colonizer, followed in the order of decreasing colonizing capacity by,A. flavus, A. niger, A. terreus andPenicillium nigricans. Sensitivity of test spores to soil fungistasis declined in the order,C. geniculata → Pestalotia sp. →A. tenuis → H. rostratum. The fungistatic level of the soil samples decreased gradually from side arms 1 to 7 of the Evans tube, inoculated with unsterilized soil from one end. Studies conducted with an inoculum of four soil fungi (A. fumigatus, A. flavus, A. niger, andP. nigricans) as well as those involving fumigation of Evans tube by CS₂ also proved the greater colonizing capacity ofA. fumigatus. The level of fungistasis followed closely the colonization pattern of this fungus. When added individually to the soil, all fungi were able to inhibit spore germination of test fungi to some degree or other.     

Comparative study of fungal cell disruption—scope and limitations of the methods

Simple and effective protocols of cell wall disruption were elaborated for tested fungal strains: Penicillium citrinum, Aspergillus fumigatus, Rhodotorula gracilis. Several techniques of cell wall disintegration were studied, including ultrasound disintegration, homogenization in bead mill, application of chemicals of various types, and osmotic shock. The release of proteins from fungal cells and the activity of a cytosolic enzyme, glucose-6-phosphate dehydrogenase, in the crude extracts were assayed to determine and compare the efficacy of each method. The presented studies allowed adjusting the particular method to a particular strain. The mechanical methods of disintegration appeared to be the most effective for the disintegration of yeast, R. gracilis, and filamentous fungi, A. fumigatus and P. citrinum. Ultrasonication and bead milling led to obtaining fungal cell-free extracts containing high concentrations of soluble proteins and active glucose-6-phosphate dehydrogenase systems.     

A comparative study of siderophore production by fungi from marine and terrestrial habitats

Siderophore producing potential of 20 fungal isolates (same 10 species from each marine and terrestrial habitat) were examined and compared. Except marine Aspergillus flavus, all isolates produced siderophores as evidenced by positive reaction in FeCl₃ test, CAS assay and CAS agar plate test. The results indicated widespread occurrence of siderophores in both the habitats. Examination of the chemical nature of siderophores revealed that mucoraceous fungi produced carboxylate, while others produced hydroxamate siderophores. Thus, the nature of siderophore was found to be independent of habitat. Among all the isolates, Cunninghamella elegans (marine form) was maximum siderophore producer (1987.5 μg/ml) followed by terrestrial form of C. elegans (1248.75 μg/ml). There was no marked variation in siderophore concentration of Penicillium funiculosum strains. Comparison of quantification of siderophore production between marine and terrestrial revealed that four terrestrial isolates (Aspergillus niger, Aspergillus ochraceous, Penicillium chrysogenum, Penicillium citrinum) were ahead in siderophore production, while, the other four marine isolates (Aspergillus versicolor, C. elegans, Rhizopus sp., Syncephalastrum racemosum) were found to be more potent siderophore producers, indicating that they were equally competent.     

Endophytic fungi from Chilean native gymnosperms: antimicrobial activity against human and phytopathogenic fungi

Thirty-eight endophytic fungi were isolated from eight Chilean gymnosperms. Isolates were characterized and grouped according to culture characteristics, colony growth, and conidia morphology. Thirteen isolates were identified: Acremonium bacillisporum, A. bactrocephalum, A. strictum, Alternaria alternata, Aureobasidium pullulans, Chaetomium funicola, Cladosporium tenuissimum, Curvularia protuberata, C. tritici, Microsphaeropsis olivacea, Penicillium chrysogenum, P. janczewskii, and Triblidiopycnis pinastri. Malbranchea and Stegonosporium were identified at the genus level. Fourteen isolates, considered to be sterile mycelia, did not fructify in the culture medium. Crude extracts of liquid cultures from endophytes were examined for antibacterial and antifungal activity against bacteria and phytopathogenic fungi using agar diffusion. Antifungal activity against pathogenic fungi was determined by microdilution assays. Extracts of Acremonium bactrocephalum, Microsphaeropsis olivacea, and isolate E-3 inhibited growth of selected pathogenic organisms, indicating they merit further study. This is the first comparative report on the antimicrobial activity of endophytic fungi from Chilean gymnosperms.     

Antifungal efficacy of bacteria isolated from marine sedentary organisms

The antibiotic-producing ability of 57 bacteria isolated from 8 marine sedentary organisms, 6 sponges (Spirastrella sp.,Phyllospongia sp.,Ircinia sp.,Aaptos sp.,Azorica sp.,Axinella sp.), 1 soft coral (Lobophytum sp.) and 1 alga (Sargassum sp.), was evaluated against 6 phytopathogenic fungi (Helminthosporium oryzae, Rhizoctonium solani, Pyricularia oryzae, Fusarium oxysporum, Aspergillus oryzae andA. fumigatus). Bacteria of the genusBacillus (20%),Pseudomonas (33%) andFlavobacterium (40%) were predominant among the heterotrophic bacteria isolated from the marine sponges, soft coral and alga, respectively. Bioassay results revealed that 36 (63%) bacterial isolates displayed antifungal activity against at least one fungus, the alga (Sargassum sp.) being the source of highest number (80%) of producer strains. Twelve bacterial isolates inhibited all fungi. The MIC of the organic extracts of 12 bacteria ranged from 0.3 to 22.8 mg/L.     

Bio-activity of fungal culture filtrates against root-knot nematode egg hatch and juvenile motility and their effects on growth of mung bean (Vigna radiata L. Wilczek) infected with the root-knot nematode,Meloidogyne incognita

Culture filtrates of selected soil fungi, namely Aspergillus flavus, Aspergillus fumigatus, Aspergillus niger, Fusarium oxysporum, Penicillium vermiculatum and Rhizopus nigricans exhibited variable response to egg hatching and mortality of the root-knot nematode, Meloidogyne incognita. Higher concentrations of the culture filtrates of all the fungi inhibited egg hatching and proved to be toxic to the juveniles of M. incognita. In addition, development of the gall and multiplication of M. incognita were also found adversely affected in varying degrees on all the plants of Vigna radiata treated with the filtrates. The culture filtrate of A. niger showed highest toxicity to the nematode than those of any other fungus tested. Soil drench application of the culture filtrates gave better seedling growth and least nematode multiplication in comparison to seed soaking treatment.