1.Regulation of Development in Aspergillus nidulans and Aspergillus fumigatus.
Mycobiology 2010;38(4):229-237
Members of the genus Aspergillus are the most common fungi and all reproduce asexually by forming long chains of conidiospores (or conidia). The impact of various Aspergillus species on humans ranges from beneficial to harmful. For example, several species including Aspergillus oryzae and Aspergillus niger are used in industry for enzyme production and food processing. In contrast, Aspergillus flavus produce the most potent naturally present carcinogen aflatoxins, which contaminate various plant- and animal-based foods. Importantly, the opportunistic human pathogen Aspergillus fumigatus has become the most prevalent airborne fungal pathogen in developed countries, causing invasive aspergillosis in immunocompromised patients with a high mortality rate. A. fumigatus produces a massive number of small hydrophobic conidia as the primary means of dispersal, survival, genome-protection, and infecting hosts. Large-scale genome-wide expression studies can now be conducted due to completion of A. fumigatus genome sequencing. However, genomics becomes more powerful and informative when combined with genetics. We have been investigating the mechanisms underlying the regulation of asexual development (conidiation) and gliotoxin biosynthesis in A. fumigatus, primarily focusing on a characterization of key developmental regulators identified in the model fungus Aspergillus nidulans. In this review, I will summarize our current understanding of how conidiation in two aspergilli is regulated.
Aflatoxins
;
Aspergillosis
;
Aspergillus
;
Aspergillus flavus
;
Aspergillus fumigatus
;
Aspergillus nidulans
;
Aspergillus niger
;
Aspergillus oryzae
;
Developed Countries
;
Food Handling
;
Fungi
;
Genome
;
Genomics
;
Gliotoxin
;
Humans
;
Immunocompromised Host
;
Spores, Fungal
;
Transcription Factors
2.The Mycobiota of Air Inside and Outside the Meju Fermentation Room and the Origin of Meju Fungi.
Dae Ho KIM ; Sun Hwa KIM ; Soon Wo KWON ; Jong Kyu LEE ; Seung Beom HONG
Mycobiology 2015;43(3):258-265
The fungi on Meju are known to play an important role as degrader of macromolecule of soybeans. In order to elucidate the origin of fungi on traditional Meju, mycobiota of the air both inside and outside traditional Meju fermentation rooms was examined. From 11 samples of air collected from inside and outside of 7 Meju fermentation rooms, 37 genera and 90 species of fungi were identified. In outside air of the fermentation room, Cladosporium sp. and Cladosporium cladosporioides were the dominant species, followed by Cladosporium tenuissimum, Eurotium sp., Phoma sp., Sistotrema brinkmannii, Alternaria sp., Aspergillus fumigatus, Schizophyllum commune, and Penicillium glabrum. In inside air of the fermentation room, Cladosporium sp., Aspergillus oryzae, Penicillium chrysogenum, Asp. nidulans, Aspergillus sp., Cla. cladosporioides, Eurotium sp., Penicillium sp., Cla. tenuissimum, Asp. niger, Eur. herbariorum, Asp. sydowii, and Eur. repens were collected with high frequency. The concentrations of the genera Aspergillus, Eurotium, and Penicillium were significantly higher in inside air than outside air. From this result and those of previous reports, the origin of fungi present on Meju was inferred. Of the dominant fungal species present on Meju, Lichtheimia ramosa, Mucor circinelloides, Mucor racemosus, and Scopulariopsis brevicaulis are thought to be originated from outside air, because these species are not or are rarely isolated from rice straw and soybean; however, they were detected outside air of fermentation room and are species commonly found in indoor environments. However, Asp. oryzae, Pen. polonicum, Eur. repens, Pen. solitum, and Eur. chevalieri, which are frequently found on Meju, are common in rice straw and could be transferred from rice straw to Meju. The fungi grow and produce abundant spores during Meju fermentation, and after the spores accumulate in the air of fermentation room, they could influence mycobiota of Meju fermentation in the following year. This could explain why concentrations of the genera Aspergillus, Eurotium, and Penicillium are much higher inside than outside of the fermentation rooms.
Alternaria
;
Aspergillus
;
Aspergillus fumigatus
;
Aspergillus nidulans
;
Aspergillus oryzae
;
Cladosporium
;
Eurotium
;
Fermentation*
;
Fungi*
;
Mucor
;
Niger
;
Oryza
;
Penicillium
;
Penicillium chrysogenum
;
Schizophyllum
;
Scopulariopsis
;
Soybeans
;
Spores
;
Viperidae
3.Effect of Temperature and Relative Humidity on Growth of Aspergillus and Penicillium spp. and Biocontrol Activity of Pseudomonas protegens AS15 against Aflatoxigenic Aspergillus flavus in Stored Rice Grains.
Mycobiology 2018;46(3):287-295
In this study, we evaluated the effect of different temperatures (10, 20, 30, and 40 °C) and relative humidities (RHs; 12, 44, 76, and 98%) on populations of predominant grain fungi (Aspergillus candidus, Aspergillus flavus, Aspergillus fumigatus, Penicillium fellutanum, and Penicillium islandicum) and the biocontrol activity of Pseudomonas protegens AS15 against aflatoxigenic A. flavus KCCM 60330 in stored rice. Populations of all the tested fungi in inoculated rice grains were significantly enhanced by both increased temperature and RH. Multiple linear regression analysis revealed that one unit increase of temperature resulted in greater effects than that of RH on fungal populations. When rice grains were treated with P. protegens AS15 prior to inoculation with A. flavus KCCM 60330, fungal populations and aflatoxin production in the inoculated grains were significantly reduced compared with the grains untreated with strain AS15 regardless of temperature and RH (except 12% RH for fungal population). In addition, bacterial populations in grains were significantly enhanced with increasing temperature and RH, regardless of bacterial treatment. Higher bacterial populations were detected in biocontrol strain-treated grains than in untreated control grains. To our knowledge, this is the first report showing consistent biocontrol activity of P. protegens against A. flavus population and aflatoxin production in stored rice grains under various environmental conditions of temperature and RH.
Aflatoxins
;
Aspergillus flavus*
;
Aspergillus fumigatus
;
Aspergillus*
;
Fungi
;
Humidity*
;
Linear Models
;
Penicillium*
;
Pseudomonas*
4.Biocontrol Activity of Volatile-Producing Bacillus megaterium and Pseudomonas protegens Against Aspergillus and Penicillium spp. Predominant in Stored Rice Grains: Study II.
Mycobiology 2018;46(1):52-63
In our previous studies, Bacillus megaterium KU143, Microbacterium testaceum KU313, and Pseudomonas protegens AS15 have been shown to be antagonistic to Aspergillus flavus in stored rice grains. In this study, the biocontrol activities of these strains were evaluated against Aspergillus candidus, Aspergillus fumigatus, Penicillium fellutanum, and Penicillium islandicum, which are predominant in stored rice grains. In vitro and in vivo antifungal activities of the bacterial strains were evaluated against the fungi on media and rice grains, respectively. The antifungal activities of the volatiles produced by the strains against fungal development and population were also tested using I-plates. In in vitro tests, the strains produced secondary metabolites capable of reducing conidial germination, germ-tube elongation, and mycelial growth of all the tested fungi. In in vivo tests, the strains significantly inhibited the fungal growth in rice grains. Additionally, in I-plate tests, strains KU143 and AS15 produced volatiles that significantly inhibited not only mycelial growth, sporulation, and conidial germination of the fungi on media but also fungal populations on rice grains. GC-MS analysis of the volatiles by strains KU143 and AS15 identified 12 and 17 compounds, respectively. Among these, the antifungal compound, 5-methyl-2-phenyl-1H-indole, was produced by strain KU143 and the antimicrobial compounds, 2-butyl 1-octanal, dimethyl disulfide, 2-isopropyl-5-methyl-1-heptanol, and 4-trifluoroacetoxyhexadecane, were produced by strain AS15. These results suggest that the tested strains producing extracellular metabolites and/or volatiles may have a broad spectrum of antifungal activities against the grain fungi. In particular, B. megaterium KU143 and P. protegens AS15 may be potential biocontrol agents against Aspergillus and Penicillium spp. during rice grain storage.
Aspergillus flavus
;
Aspergillus fumigatus
;
Aspergillus*
;
Bacillus megaterium*
;
Bacillus*
;
Fungi
;
Germination
;
In Vitro Techniques
;
Penicillium*
;
Pseudomonas*
5.Application of PCR combined with reverse line blot assay in detection and identification of common pathogenic Aspergillus in fungal sinusitis.
Li-li LI ; Zuo-tao ZHAO ; Zhe WAN ; Ruo-yu LI ; Hong-gang LIU
Chinese Journal of Pathology 2012;41(1):6-10
OBJECTIVETo evaluate the feasibility of PCR/reverse line blot hybridization (RLB) assay in the detection and identification of clinical pathogens in fungal sinusitis (FS).
METHODSTwenty-six formalin-fixed and paraffin-embedded tissues and 8 fresh tissues of FS were collected from Beijing Tongren Hospital, Capital Medical University from May 2009 to February 2010. Pathological examination, fungal culture and ITS2 region sequencing were carried out. The DNA of all samples was extracted by standard procedure and fungal universal primers ITS3 and ITS4 were used for PCR amplification of all tissues. Then the amplified products were used for RLB with five fungal species-specific probes. The results of PCR/RLB were compared with ITS region sequencing, fungal culture and pathological examination.
RESULTSFor the biopsy tissues, fungal cultures were positive in 14 cases (41.2%); pathologic examination demonstrated fungal hyphae in all cases; ITS2 region sequencing was successful in 16 cases (47.1%); PCR/RLB showed A. flavus in 14 cases, A. fumigatus in 10 cases, A. niger in four cases, A. nidulans in one case, A. flavus and A. fumigatus in three cases, and A. fumigatus and A. niger in two cases.
CONCLUSIONSThe PCR/RLB assay is suitable for rapid and accurate detection and identification of the pathogenic fungus of FS. Compared with the conventional fungal culture and microscopy, pathologic examination and DNA sequencing, the PCR/RLB has the advantages of more economy, time saving, and higher sensitivity, specificity and throughput.
Aspergillus ; classification ; genetics ; isolation & purification ; Aspergillus flavus ; genetics ; isolation & purification ; Aspergillus fumigatus ; genetics ; isolation & purification ; Aspergillus niger ; genetics ; isolation & purification ; DNA Primers ; DNA, Fungal ; genetics ; Humans ; Mycoses ; diagnosis ; microbiology ; Nucleic Acid Hybridization ; methods ; Polymerase Chain Reaction ; methods ; Sensitivity and Specificity ; Sinusitis ; diagnosis ; microbiology
6.Improved Transformation of the Filamentous Fungus Aspergillus niger Using Agrobacterium tumefaciens.
Mycobiology 2001;29(3):132-134
Since it is known that Agrobacterium tumefaciens, which has long been used to transform plants, can transfer the T-DNA to yeast Saccharomyces cerevisiae during tumourigenesis, a variety of fungi were subjected to transformation to improve their transformation frequency. In this study, I report the A. tumefaciens-mediated transformation of filamentous fungus Aspergillus niger. Transfer of the binary vector pBIN9-Hg, containing the bacterial hygromycin B phosphotransferase gene under the control of the Aspergillus nidulans trpC promoter and terminator as a selectable marker, led to the selection of 50~100 hygromycin B-resistant transformants per 1x10(7) conidia of A. niger. This efficiency is improved 10~20 fold more than reported elsewhere. In order to avoid the difficulties in selection transformant from the over-growing non-transformant, I used top agar containing 900 microg/ml of hygromycin. Genomic PCR and Southern analysis showed that all transformants contained single T-DNA insert per fungal genome. This technique offers an easier and more efficient method than that of using protoplast.
Agar
;
Agrobacterium tumefaciens*
;
Agrobacterium*
;
Aspergillus nidulans
;
Aspergillus niger*
;
Aspergillus*
;
Fungi*
;
Genome, Fungal
;
Hygromycin B
;
Niger
;
Polymerase Chain Reaction
;
Protoplasts
;
Saccharomyces cerevisiae
;
Spores, Fungal
;
Yeasts
7.Antifungal Activity of Methyl 2-Benzimidazole Carbamate.
Mycobiology 2003;31(2):81-85
Antifungal properties of methyl 2-benzimidazole carbamate (BMC) were investigated using 16 fungi. Cytotoxicity test of BMC revealed that the morphology of HeLa cells was considerably deformed even at the concentrations as low as 0.1 ppm. Minimum inhibitory concentration (MIC) values of BMC for 7 fungi among the 16 tested ones were lower than 1.95x10(-4) microg/ml, while Aspergillus flavus showed an MIC value higher than 1.0 microg/ml. Tolerance induction against BMC was successful only for Paecilomyces farinosus LAR10, contrary to the expectation that tolerance would be induced for the fungi having high MIC values such as Aspergillus niger ATCC 9642 and A. flavus ATCC 9643. Spore germination of A. niger ATCC 9642 was suppressed by BMC. However the mycelial growth of the fungus once germinated was not retarded at all by BMC up to 8 MIC. Addition of lanosterol provided a remedy for the reduced germination rate of A. niger ATCC 9642 spores.
Aspergillus flavus
;
Aspergillus niger
;
Fungi
;
Germination
;
HeLa Cells
;
Humans
;
Lanosterol
;
Microbial Sensitivity Tests
;
Niger
;
Paecilomyces
;
Spores
8.The use of phosphorus nanoparticles synthesized by rhizospheric fungus Aspergillius fumigatus as a nanofertilizer for flax plant
Rabaa Yaseen ; Basma Hamdy Amin
Malaysian Journal of Microbiology 2021;17(3):244-253
Aims:
This study examined the mycosynthesis of phosphorus nanoparticles (PNPs) and its application as a fertilizer for flax plant.
Methodology and results:
A total of thirty eight fungal isolates were isolated and screened for their abilities to
synthesize PNPs. The fungal isolate was determined and identified as Aspergillus fumigatus (NCBI GenBank accession
No. MN610566-MN610567). The biosynthesized nanoparticles were characterized by particle size analyzer, UV-visible
spectrophotometer, transmission electron microscope (TEM), energy-dispersive X-ray spectroscopy (EDX) and fourier
transform infrared spectroscopy (FT-IR). They were found to have an average diameter of 45.1 nm, regular round
shape, EDX confirms the 54.63 atom % of phosphorous. The cytotoxicity of produced nanoparticles was performed to
determine the safe dose that will be applied in agricultural experiment and was found to be 12.5 μg/mL. Pot experiment
was performed to determine the fertilizing impact of mycosynthesized PNPs on flax plant and to equate their influence
with granular single super phosphate. Results revealed that growth parameters, phosphorus content and microbial
activities in the rhizosphere of flax plants were highly significantly (p ≤ 0.05) affected by foliar application of PNPs in
presence of half dose of super phosphate. The TEM-micrographs of stained ultrastructural leaves showed that the PNPs
treated leaves in the presence of half dose of super phosphate had normal cell structure similar to control, while the cell
structure of leaves treated with PNPs but did not receive super phosphate were adversely affected.
Conclusion, significance and impact of study
This study clearly indicated that the application of low cost
biosynthesised PNPs could save about 50% of recommended dose of phosphorus fertilizer. This study also
demonstrates that it is not preferred to use PNPs as a fertilizer alone without adding super phosphate. Hence, this
investigation suggests that further studies should be established to detect the safety of this nanofertilizers.
Nanoparticles--chemistry
;
Aspergillus fumigatus
9.Isolation and Identification of Aspergillus Section Fumigati Strains from Arable Soil in Korea.
Seung Beom HONG ; Dae Ho KIM ; In Cheol PARK ; Robert A SAMSON ; Hyeon Dong SHIN
Mycobiology 2010;38(1):1-6
63 strains of Aspergillus section Fumigati were isolated from 17 samples of arable soil in a central province of Korea. Based on the results of genotypic and phenotypic analyses, they were identified as Aspergillus fumigatus, A. lentulus, Neosartorya coreana, N. fennelliae, N. fischeri, N. glabra, N. hiratsukae, N. laciniosa, N. pseudofischeri, N. quadricincta, N. spinosa and N. udagawae. Among these, N. fennelliae, N. hiratsukae, N. quadricincta, and N. udagawae had not been previously recorded in Korea. The diversity of Aspergillus section Fumigati species from arable soil in Korea is also addressed.
Aspergillus
;
Aspergillus fumigatus
;
Korea
;
Neosartorya
;
Soil
10.Aspergillus Associated with Meju, a Fermented Soybean Starting Material for Traditional Soy Sauce and Soybean Paste in Korea.
Seung Beom HONG ; Dae Ho KIM ; Robert A SAMSON
Mycobiology 2015;43(3):218-224
Aspergillus is an important fungal genus used for the fermentation of Asian foods; this genus is referred to as koji mold in Japan and China. A. oryzae, A. sojae, and A. tamari are used in the production of miso and shoyu in Japan, but a comprehensive taxonomic study of Aspergillus isolated from Meju, a fermented soybean starting material for traditional soy sauce and soybean paste in Korea, has not been conducted. In this study, various Aspergillus species were isolated during a study of the mycobiota of Meju, and the aspergilli were identified based on phenotypic characteristics and sequencing of the beta-tubulin gene. Most strains of Aspergillus were found to belong to the following sections: Aspergillus (n = 220), Flavi (n = 213), and Nigri (n = 54). The most commonly identified species were A. oryzae (n = 183), A. pseudoglaucus (Eurotium repens) (n = 81), A. chevalieri (E. chevalieri) (n = 62), A. montevidensis (E. amstelodami) (n = 34), A. niger (n = 21), A. tamari (n = 15), A. ruber (E. rubrum) (n = 15), A. proliferans (n = 14), and A. luchuensis (n = 14); 25 species were identified from 533 Aspergillus strains. Aspergillus strains were mainly found during the high temperature fermentation period in the later steps of Meju fermentation.
Asian Continental Ancestry Group
;
Aspergillus oryzae
;
Aspergillus*
;
China
;
Fermentation
;
Fungi
;
Humans
;
Japan
;
Korea*
;
Niger
;
Oryza
;
Soy Foods*
;
Soybeans*
;
Tubulin