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Expanding the species and chemical diversity of Penicillium section Cinnamopurpurea. PLoS One 2015; 10:e0121987. [PMID: 25853891 PMCID: PMC4390383 DOI: 10.1371/journal.pone.0121987] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2014] [Accepted: 02/06/2015] [Indexed: 11/19/2022] Open
Abstract
A set of isolates very similar to or potentially conspecific with an unidentified Penicillium isolate NRRL 735, was assembled using a BLAST search of ITS similarity among described (GenBank) and undescribed Penicillium isolates in our laboratories. DNA was amplified from six loci of the assembled isolates and sequenced. Two species in section Cinnamopurpurea are self-compatible sexual species, but the asexual species had polymorphic loci suggestive of sexual reproduction and variation in conidium size suggestive of ploidy level differences typical of heterothallism. Accordingly we use genealogical concordance analysis, a technique valid only in heterothallic organisms, for putatively asexual species. Seven new species were revealed in the analysis and are described here. Extrolite analysis showed that two of the new species, P. colei and P. monsserratidens produce the mycotoxin citreoviridin that has demonstrated pharmacological activity against human lung tumors. These isolates could provide leads in pharmaceutical research.
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52
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Cacho RA, Tang Y, Chooi YH. Next-generation sequencing approach for connecting secondary metabolites to biosynthetic gene clusters in fungi. Front Microbiol 2015; 5:774. [PMID: 25642215 PMCID: PMC4294208 DOI: 10.3389/fmicb.2014.00774] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2014] [Accepted: 12/17/2014] [Indexed: 12/20/2022] Open
Abstract
Genomics has revolutionized the research on fungal secondary metabolite (SM) biosynthesis. To elucidate the molecular and enzymatic mechanisms underlying the biosynthesis of a specific SM compound, the important first step is often to find the genes that responsible for its synthesis. The accessibility to fungal genome sequences allows the bypass of the cumbersome traditional library construction and screening approach. The advance in next-generation sequencing (NGS) technologies have further improved the speed and reduced the cost of microbial genome sequencing in the past few years, which has accelerated the research in this field. Here, we will present an example work flow for identifying the gene cluster encoding the biosynthesis of SMs of interest using an NGS approach. We will also review the different strategies that can be employed to pinpoint the targeted gene clusters rapidly by giving several examples stemming from our work.
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Affiliation(s)
- Ralph A Cacho
- Chemical and Biomolecular Engineering Department, University of California Los Angeles, Los Angeles, CA, USA
| | - Yi Tang
- Chemical and Biomolecular Engineering Department, University of California Los Angeles, Los Angeles, CA, USA ; Chemistry and Biochemistry Department, University of California Los Angeles, Los Angeles, CA, USA
| | - Yit-Heng Chooi
- Plant Sciences Division, Research School of Biology, The Australian National University Canberra, ACT, Australia
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54
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Hubka V, Nováková A, Kolařík M, Jurjević Ž, Peterson SW. Revision of Aspergillus section Flavipedes: seven new species and proposal of section Jani sect. nov. Mycologia 2014; 107:169-208. [PMID: 25344259 DOI: 10.3852/14-059] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Aspergillus section Flavipedes contains species found worldwide in soils and rhizospheres, indoor and cave environments, as endophytes, food contaminants and occasionally as human pathogens. They produce many extensively studied bioactive secondary metabolites and biotechnologically relevant enzymes. The taxa were revised based on phylogenetic analysis of sequences from four loci (β-tubulin, calmodulin, RPB2, ITS rDNA), two PCR fingerprinting methods, micro- and macromorphology and physiology. Section Flavipedes includes three known and seven new species: A. ardalensis, A. frequens, A. luppii, A. mangaliensis, A. movilensis, A. polyporicola and A. spelaeus. The name A. neoflavipes was proposed for Fennellia flavipes a distinct species from its supposed asexual state A. flavipes. Aspergillus iizukae, A. frequens and A. mangaliensis are the most common and widely distributed species, whereas A. flavipes s. str. is rare. A dichotomous key based on the combination of morphology and physiology is provided for all recognized species. Aspergillus section Jani is established to contain A. janus and A. brevijanus, species previously classified as members of sect. Versicolores, Terrei or Flavipedes. This new section is strongly supported by phylogenetic data and morphology. Section Jani species produce three types of conidiophores and conidia, and colonies have green and white sectors making them distinctive. Accessory conidia found in pathogenic A. terreus were found in all members of sects. Flavipedes and Jani. Our data indicated that A. frequens is a clinically relevant and produces accessory conidia during infection.
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Affiliation(s)
- Vit Hubka
- Department of Botany, Faculty of Science, Charles University in Prague, Benátská 2, 128 01 Prague 2, Czech RepublicInstitute of Microbiology AS CR, v.v.i, Vídeňská 1083, 142 20 Prague 4, Czech Republic
| | - Alena Nováková
- Institute of Microbiology AS CR, v.v.i, Vídeňská 1083, 142 20 Prague 4, Czech Republic, and Institute of Soil Biology, Biology Centre AS CR, v.v.i., Na Sádkách 7, 370 05 České Budějovice, Czech Republic
| | - Miroslav Kolařík
- Department of Botany, Faculty of Science, Charles University in Prague, Benátská 2, 128 01 Prague 2, Czech Republic, and Institute of Microbiology AS CR, v.v.i, Vídeňská 1083, 142 20 Prague 4, Czech Republic
| | - Željko Jurjević
- EMSL Analytical Inc., 200 Route 130 North, Cinnaminson, New Jersey 08077
| | - Stephen W Peterson
- Bacterial Foodborne Pathogens and Mycology Research Unit, National Center for Agricultural Utilization Research, 1815 N. University Street, Peoria, Illinois 61604
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55
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Howard SJ. Multi-Resistant Aspergillosis due to Cryptic Species. Mycopathologia 2014; 178:435-9. [DOI: 10.1007/s11046-014-9774-0] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2014] [Accepted: 06/15/2014] [Indexed: 11/24/2022]
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56
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Igarashi Y, Hanafusa T, Gohda F, Peterson S, Bills G. Species-level assessment of secondary metabolite diversity among Hamigera species and a taxonomic note on the genus. Mycology 2014; 5:102-109. [PMID: 25379334 PMCID: PMC4205921 DOI: 10.1080/21501203.2014.917736] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2014] [Accepted: 03/27/2014] [Indexed: 12/23/2022] Open
Abstract
Secondary metabolite phenotypes in nine species of the Hamigera clade were analysed to assess their correlations to a multi-gene species-level phylogeny. High-pressure-liquid-chromatography-based chemical analysis revealed three distinctive patterns of secondary metabolite production: (1) the nine species could be divided into two groups on the basis of production of the sesquiterpene tricinonoic acid; (2) the tricinonoic acid-producing group produced two cyclic peptides avellanins A and B; (3) the tricinonoic acid-non-producing group could be further divided into two groups according to the production of avellanins A and B. The chemical phenotype was consistent with the phylogeny of the species, although metabolite patterns were not diagnostic at the species level. In addition, the taxonomy of the Hamigera clade was updated with the new combination Hamigera ingelheimensis proposed for Merimbla ingelheimensis, so that all species in the clade are now in the same genus.
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Affiliation(s)
- Yasuhiro Igarashi
- Department of Biotechnology and Biotechnology Research Center, Toyama Prefectural University , 5180 Kurokawa, Imizu , Toyama 939-0398 , Japan
| | - Tomoaki Hanafusa
- Department of Biotechnology and Biotechnology Research Center, Toyama Prefectural University , 5180 Kurokawa, Imizu , Toyama 939-0398 , Japan
| | - Fumiya Gohda
- Department of Biotechnology and Biotechnology Research Center, Toyama Prefectural University , 5180 Kurokawa, Imizu , Toyama 939-0398 , Japan
| | - Stephen Peterson
- US Department of Agriculture, National Center for Agricultural Utilization Research , 1815 North University Street, Peoria , IL 61604 , USA
| | - Gerald Bills
- Texas Therapeutics Institute, The Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center at Houston , 1881 East Road, Houston , TX 77054 , USA
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57
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Palencia ER, Mitchell TR, Snook ME, Glenn AE, Gold S, Hinton DM, Riley RT, Bacon CW. Analyses of black Aspergillus species of peanut and maize for ochratoxins and fumonisins. J Food Prot 2014; 77:805-13. [PMID: 24780336 DOI: 10.4315/0362-028x.jfp-13-321] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The genus Aspergillus section Nigri, or the black aspergilli, represents genetically closely related species that produce the mycotoxins, ochratoxins and the fumonisins. Fumonisin B1 (FB1) is of an added concern because it is also a virulence factor for maize. Our preliminary data indicated that black aspergilli could develop asymptomatic infections with maize and peanuts plants. Symptomless infections are potential problems, because under favorable conditions, there is a potential for accumulation of ochratoxins and the fumonisins in contaminated postharvest crops. In the present report, the ability of black aspergilli from peanuts and maize to produce ochratoxin A and FB1 on maize kernels was assessed. One hundred fifty strains from peanuts and maize were isolated from several southeastern and midwestern states. Aspergillus nigri (A. nigri var. nigri) was the dominant species (87%), while Aspergillus foetidus, Aspergillus japonicus, Aspergillus tubingensis, and Aspergillus carbonarius were infrequently isolated. None of the wild isolates produced detectable amounts of ochratoxins. However, we do report the occurrence of the fumonisins B1, B2, and B3. Of 54 field isolates, 30% (n = 16) produced FB1, 61% (n = 33) produced FB2, and 44% (n = 24) produced FB3. The amounts of fumonisins produced during the test period of 30 days suggest that these strains might be weak to moderate producers of fumonisin on maize. To our knowledge, this is a first report of FB1 and FB3 production by isolates of black aspergilli from an American cereal and legume.
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Affiliation(s)
- Edwin R Palencia
- U.S. Department of Agriculture, Agricultural Research Service, Russell Research Center, Toxicology and Mycotoxin Research Unit, Athens, Georgia 30605, USA; Department of Plant Pathology, University of Georgia, Athens, Georgia 30604, USA; U.S. Department of Agriculture, Agricultural Research Service, National Peanut Research Laboratory, 1011 Forrester Drive S.E., P.O. Box 509, Dawson, GA 39842, USA
| | - Trevor R Mitchell
- U.S. Department of Agriculture, Agricultural Research Service, Russell Research Center, Toxicology and Mycotoxin Research Unit, Athens, Georgia 30605, USA
| | - Maurice E Snook
- U.S. Department of Agriculture, Agricultural Research Service, Russell Research Center, Toxicology and Mycotoxin Research Unit, Athens, Georgia 30605, USA
| | - Anthony E Glenn
- U.S. Department of Agriculture, Agricultural Research Service, Russell Research Center, Toxicology and Mycotoxin Research Unit, Athens, Georgia 30605, USA
| | - Scott Gold
- U.S. Department of Agriculture, Agricultural Research Service, Russell Research Center, Toxicology and Mycotoxin Research Unit, Athens, Georgia 30605, USA
| | - Dorothy M Hinton
- U.S. Department of Agriculture, Agricultural Research Service, Russell Research Center, Toxicology and Mycotoxin Research Unit, Athens, Georgia 30605, USA
| | - Ronald T Riley
- U.S. Department of Agriculture, Agricultural Research Service, Russell Research Center, Toxicology and Mycotoxin Research Unit, Athens, Georgia 30605, USA
| | - Charles W Bacon
- U.S. Department of Agriculture, Agricultural Research Service, Russell Research Center, Toxicology and Mycotoxin Research Unit, Athens, Georgia 30605.
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58
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Frisvad JC, Petersen LM, Lyhne EK, Larsen TO. Formation of sclerotia and production of indoloterpenes by Aspergillus niger and other species in section Nigri. PLoS One 2014; 9:e94857. [PMID: 24736731 PMCID: PMC3988082 DOI: 10.1371/journal.pone.0094857] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2013] [Accepted: 03/19/2014] [Indexed: 01/04/2023] Open
Abstract
Several species in Aspergillus section Nigri have been reported to produce sclerotia on well-known growth media, such as Czapek yeast autolysate (CYA) agar, with sclerotia considered to be an important prerequisite for sexual development. However Aspergillus niger sensu stricto has not been reported to produce sclerotia, and is thought to be a purely asexual organism. Here we report, for the first time, the production of sclerotia by certain strains of Aspergillus niger when grown on CYA agar with raisins, or on other fruits or on rice. Up to 11 apolar indoloterpenes of the aflavinine type were detected by liquid chromatography and diode array and mass spectrometric detection where sclerotia were formed, including 10,23-dihydro-24,25-dehydroaflavinine. Sclerotium induction can thus be a way of inducing the production of new secondary metabolites from previously silent gene clusters. Cultivation of other species of the black aspergilli showed that raisins induced sclerotium formation by A. brasiliensis, A. floridensis A. ibericus, A. luchuensis, A. neoniger, A. trinidadensis and A. saccharolyticus for the first time.
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Affiliation(s)
- Jens C. Frisvad
- Chemodiversity Group, Department of Systems Biology, Technical University of Denmark, Lyngby, Denmark
- * E-mail:
| | - Lene M. Petersen
- Chemodiversity Group, Department of Systems Biology, Technical University of Denmark, Lyngby, Denmark
| | - E. Kirstine Lyhne
- Chemodiversity Group, Department of Systems Biology, Technical University of Denmark, Lyngby, Denmark
| | - Thomas O. Larsen
- Chemodiversity Group, Department of Systems Biology, Technical University of Denmark, Lyngby, Denmark
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59
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Malysheva SV, Arroyo-Manzanares N, Cary JW, Ehrlich KC, Vanden Bussche J, Vanhaecke L, Bhatnagar D, Di Mavungu JD, De Saeger S. Identification of novel metabolites from Aspergillus flavus by high resolution and multiple stage mass spectrometry. Food Addit Contam Part A Chem Anal Control Expo Risk Assess 2014; 31:111-20. [PMID: 24405210 DOI: 10.1080/19440049.2013.859743] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
The filamentous fungus Aspergillus flavus is one of the most important species in the Aspergillus genus and is distributed worldwide as a prevalent aflatoxin-producing food and feed contaminant. A. flavus contains more than 55 gene clusters that are predicted to encode proteins involved in secondary metabolite production. One of these, cluster 27, contains a polyketide synthase (pks27) gene that encodes a protein that is highly homologous to the aflatoxin cluster PKS. Comparative metabolomics, using ultra-high performance liquid chromatography (UHPLC) coupled to high resolution Orbitrap mass spectrometry (MS) was used to detect metabolites differentially expressed in the A. flavus wild-type and ∆pks27 mutant strains. Metabolite profiling was aided by a statistical differential analysis of MS data using SIEVE software. This differential analysis combined with accurate mass data from the Orbitrap and ion trap multiple stage MS allowed four metabolites to be identified that were produced only by the wild-type culture. These included asparasone A (358 Da), an anthraquinone pigment, and related anthraquinones with masses of 316, 340 and 374 Da. These latter three compounds had similar fragmentation patterns to that of asparasone A. The 316 Da anthraquinone is particularly interesting because it is most likely formed by incorporation of seven malonyl-CoA units rather than the eight units required for the formation of asparasone A. The 340 and 374 Da metabolites are the dehydration and an oxy-derivative of asparasone A, respectively. Asparasone A was also identified in extracts from several other Aspergillus species.
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Affiliation(s)
- Svetlana V Malysheva
- a Laboratory of Food Analysis, Faculty of Pharmaceutical Sciences , Ghent University , Ghent , Belgium
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60
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Characterization of nonochratoxigenic strains of Aspergillus carbonarius from grapes. Food Microbiol 2013; 36:135-41. [DOI: 10.1016/j.fm.2013.05.004] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2013] [Revised: 04/05/2013] [Accepted: 05/16/2013] [Indexed: 11/17/2022]
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61
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Hyun SH, Lee SY, Sung GH, Kim SH, Choi HK. Metabolic profiles and free radical scavenging activity of Cordyceps bassiana fruiting bodies according to developmental stage. PLoS One 2013; 8:e73065. [PMID: 24058459 PMCID: PMC3772819 DOI: 10.1371/journal.pone.0073065] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2013] [Accepted: 07/15/2013] [Indexed: 11/18/2022] Open
Abstract
The metabolic profiles of Cordyceps bassiana according to fruiting body developmental stage were investigated using gas chromatography-mass spectrometry. We were able to detect 62 metabolites, including 48 metabolites from 70% methanol extracts and 14 metabolites from 100% n-hexane extracts. These metabolites were classified as alcohols, amino acids, organic acids, phosphoric acids, purine nucleosides and bases, sugars, saturated fatty acids, unsaturated fatty acids, or fatty amides. Significant changes in metabolite levels were found according to developmental stage. Relative levels of amino acids, purine nucleosides, and sugars were higher in development stage 3 than in the other stages. Among the amino acids, valine, isoleucine, lysine, histidine, glutamine, and aspartic acid, which are associated with ABC transporters and aminoacyl-tRNA biosynthesis, also showed higher levels in stage 3 samples. The free radical scavenging activities, which were significantly higher in stage 3 than in the other stages, showed a positive correlation with purine nucleoside metabolites such as adenosine, guanosine, and inosine. These results not only show metabolic profiles, but also suggest the metabolic pathways associated with fruiting body development stages in cultivated C. bassiana.
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Affiliation(s)
- Sun-Hee Hyun
- College of Pharmacy, Chung-Ang University, Seoul, Republic of Korea
| | - Seok-Young Lee
- College of Pharmacy, Chung-Ang University, Seoul, Republic of Korea
| | - Gi-Ho Sung
- Mushroom Research Division, Department of Herbal Crop Research, National Institute of Horticultural and Herbal Science, RDA, Suwon, Republic of Korea
| | - Seong Hwan Kim
- Department of Microbiology, Dankook University, Cheonan, Republic of Korea
| | - Hyung-Kyoon Choi
- College of Pharmacy, Chung-Ang University, Seoul, Republic of Korea
- * E-mail:
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62
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Krimitzas A, Pyrri I, Kouvelis VN, Kapsanaki-Gotsi E, Typas MA. A phylogenetic analysis of Greek isolates of Aspergillus species based on morphology and nuclear and mitochondrial gene sequences. BIOMED RESEARCH INTERNATIONAL 2013; 2013:260395. [PMID: 23762830 PMCID: PMC3665174 DOI: 10.1155/2013/260395] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/13/2013] [Accepted: 04/09/2013] [Indexed: 12/13/2022]
Abstract
Aspergillus species originating from Greece were examined by morphological and molecular criteria to explore the diversity of this genus. The phylogenetic relationships of these species were determined using sequences from the ITS and IGS region of the nuclear rRNA gene complex, two nuclear genes ( β -tubulin (benA) and RNA polymerase II second largest subunit (rpb2)) and two mitochondrial genes (small rRNA subunit (rns) and cytochrome oxidase subunit I (cox1)) and, where available, related sequences from databases. The morphological characters of the anamorphs and teleomorphs, and the single gene phylogenetic trees, differentiated and placed the species examined in the well-supported sections of Aenei, Aspergillus, Bispori, Candidi, Circumdati, Clavati, Cremei, Flavi, Flavipedes, Fumigati, Nidulantes, Nigri, Restricti, Terrei, Usti, and Zonati, with few uncertainties. The combined use of the three commonly employed nuclear genes (benA, rpb2, and ITS), the IGS region, and two less often used mitochondrial gene sequences (rns and cox1) as a single unit resolved several taxonomic ambiguities. A phylogenetic tree was inferred using Neighbour-Joining, Maximum Parsimony, and Bayesian methods. The strains examined formed seven well-supported clades within the genus Aspergillus. Altogether, the concatenated nuclear and mitochondrial sequences offer additional tools for an improved understanding of phylogenetic relationships within this genus.
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Affiliation(s)
- Antonios Krimitzas
- Department of Genetics and Biotechnology, Faculty of Biology, National and Kapodistrian University of Athens, Panepistemiopolis, 15701 Athens, Greece
| | - Ioanna Pyrri
- Department of Ecology and Systematics, Faculty of Biology, National and Kapodistrian University of Athens, Panepistemiopolis, 15784 Athens, Greece
| | - Vassili N. Kouvelis
- Department of Genetics and Biotechnology, Faculty of Biology, National and Kapodistrian University of Athens, Panepistemiopolis, 15701 Athens, Greece
| | - Evangelia Kapsanaki-Gotsi
- Department of Ecology and Systematics, Faculty of Biology, National and Kapodistrian University of Athens, Panepistemiopolis, 15784 Athens, Greece
| | - Milton A. Typas
- Department of Genetics and Biotechnology, Faculty of Biology, National and Kapodistrian University of Athens, Panepistemiopolis, 15701 Athens, Greece
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63
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Culture condition-dependent metabolite profiling of Aspergillus fumigatus with antifungal activity. Fungal Biol 2013; 117:211-9. [PMID: 23537878 DOI: 10.1016/j.funbio.2013.01.009] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2012] [Revised: 01/15/2013] [Accepted: 01/22/2013] [Indexed: 11/22/2022]
Abstract
Three sections of Aspergillus (five species, 21 strains) were classified according to culture medium-dependent and time-dependent secondary metabolite profile-based chemotaxonomy. Secondary metabolites were analysed by liquid chromatography-electrospray ionisation tandem mass spectrometry (LC-ESI-MS-MS) and multivariate statistical methods. From the Aspergillus sections that were cultured on malt extract agar (MEA) and Czapek yeast extract agar (CYA) for 7, 12, and 16 d, Aspergillus sections Fumigati (A. fumigatus), Nigri (A. niger), and Flavi (A. flavus, A. oryzae, and A. sojae) clustered separately on the basis of the results of the secondary metabolite analyses at 16 d regardless of culture medium. Based on orthogonal projection to latent structures discriminant analysis by partial least squares discriminant analysis (PLS-DA), we identified the secondary metabolites that helped differentiate sections between A. fumigatus and Aspergillus section Flavi to be gliotoxin G, fumigatin oxide, fumigatin, pseurotin A or D, fumiquinazoline D, fumagillin, helvolic acid, 1,2-dihydrohelvolic acid, and 5,8-dihydroxy-9,12-octadecadienoic acid (5,8-diHODE). Among these compounds, fumagillin, helvolic acid, and 1,2-dihydrohelvolic acid of A. fumigatus showed antifungal activities against Malassezia furfur, which is lipophilic yeast that causes epidermal skin disorders.
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64
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Breaking the silence: protein stabilization uncovers silenced biosynthetic gene clusters in the fungus Aspergillus nidulans. Appl Environ Microbiol 2012; 78:8234-44. [PMID: 23001671 DOI: 10.1128/aem.01808-12] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
The genomes of filamentous fungi comprise numerous putative gene clusters coding for the biosynthesis of chemically and structurally diverse secondary metabolites (SMs), which are rarely expressed under laboratory conditions. Previous approaches to activate these genes were based primarily on artificially targeting the cellular protein synthesis apparatus. Here, we applied an alternative approach of genetically impairing the protein degradation apparatus of the model fungus Aspergillus nidulans by deleting the conserved eukaryotic csnE/CSN5 deneddylase subunit of the COP9 signalosome. This defect in protein degradation results in the activation of a previously silenced gene cluster comprising a polyketide synthase gene producing the antibiotic 2,4-dihydroxy-3-methyl-6-(2-oxopropyl)benzaldehyde (DHMBA). The csnE/CSN5 gene is highly conserved in fungi, and therefore, the deletion is a feasible approach for the identification of new SMs.
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65
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Kandasamy S, Sahu SK, Kandasamy K. In Silico Studies on Fungal Metabolite against Skin Cancer Protein (4,5-Diarylisoxazole HSP90 Chaperone). ISRN DERMATOLOGY 2012; 2012:626214. [PMID: 22991673 PMCID: PMC3443584 DOI: 10.5402/2012/626214] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/18/2012] [Accepted: 08/05/2012] [Indexed: 01/06/2023]
Abstract
This work was to find out the dominant secondary metabolites derived from the fungus Trichoderma and to test them against skin cancer protein. The metabolites were extracted in 80% methanol from the fungal biomass of Trichoderma isolated from mangrove sediment. The crude methanol extract was purified and analysed for the secondary metabolites by GC-MS. Three predominant compounds (heptadecanoic acid, 16 methyl-, methyl ester; 9,12-octadecadienoic acid; cis-9-octadecenoic acid) identified in the extracts were screened against the skin cancer protein (Hsp90) by in-silico docking method. Of the compounds, heptadecanoic acid, 16 methyl, methyl ester was the most potent having the docking score of -11.4592 Kcal/mol. This value was better than the standard drug "dyclonine". This work recommends the heptadecanoic acid, 16 methyl, methyl ester for further in vitro and in vivo studies towards its development as anticancer drug.
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Affiliation(s)
- Saravanakumar Kandasamy
- Centre of Advanced Study in Marine Biology, Faculty of Marine Sciences, Annamalai University, Parangipettai 608 502, India
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66
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Development and application of a loop-mediated isothermal amplification assay for rapid identification of aflatoxigenic molds and their detection in food samples. Int J Food Microbiol 2012; 159:214-24. [PMID: 23107500 DOI: 10.1016/j.ijfoodmicro.2012.08.018] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2012] [Revised: 08/24/2012] [Accepted: 08/28/2012] [Indexed: 11/21/2022]
Abstract
Aflatoxins are the most thoroughly studied mycotoxins. They are produced by several members of the genus Aspergillus in section Flavi with Aspergillus flavus, Aspergillus parasiticus, and Aspergillus nomius being frequently isolated from contaminated food sources. In this work, we describe the development and evaluation of loop-mediated isothermal amplification (LAMP) assays for rapid detection of the three species in separate analyses. The acl1-gene of A. flavus and amy1-genes of A. nomius and A. parasiticus were used as target genes. The detection limits were 2.4, 7.6 and 20pg of pure DNA/reaction for A. flavus, A. nomius and A. parasiticus, respectively. For specificity testing, DNA extracted from mycelia of representative strains of 39 Aspergillus species, 23 Penicillium species, 75 Fusarium species and 37 other fungal species was used as a template for the specific LAMP primer sets developed for the three target species. The LAMP assay was combined with a DNA extraction method for the analysis of pure fungal cultures as well as artificially contaminated Brazil nuts, peanuts and green coffee beans. It is suggested that the developed LAMP assay is a promising tool in the prediction of a potential aflatoxin risk in food and food raw materials and may therefore be suitable for high throughput analysis in the food industry.
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67
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Aspergillus saccharolyticus sp. nov., a black Aspergillus species isolated in Denmark. Int J Syst Evol Microbiol 2011; 61:3077-3083. [DOI: 10.1099/ijs.0.029884-0] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
A novel species, Aspergillus saccharolyticus sp. nov., belonging to the Aspergillus section Nigri group is described. This species was isolated in Denmark from treated hardwood. Its taxonomic status was determined using a polyphasic taxonomic approach including phenotypic (morphology and extrolite profiles) and molecular (β-tubulin, internal transcribed spacer and calmodulin gene sequences, and universally primed PCR fingerprinting) analysis. Phenotypic and molecular data enabled this novel species to be clearly distinguished from other black aspergilli. A. saccharolyticus is a uniseriate Aspergillus species that is morphologically similar to Aspergillus japonicus and Aspergillus aculeatus, but has a totally different extrolite profile compared to any known Aspergillus species. The type strain of A. saccharolyticus sp. nov. is CBS 127449T ( = IBT 28509T).
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Varga J, Frisvad J, Kocsubé S, Brankovics B, Tóth B, Szigeti G, Samson R. New and revisited species in Aspergillus section Nigri. Stud Mycol 2011; 69:1-17. [PMID: 21892239 PMCID: PMC3161757 DOI: 10.3114/sim.2011.69.01] [Citation(s) in RCA: 164] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Four new species, Aspergillus eucalypticola, A. neoniger, A. fijiensis and A. indologenus are described and illustrated. Aspergillus eucalypticola was isolated from Eucalyptus leaf from Australia, and is related to A. tubingensis and A. costaricaensis, but could clearly be distinguished from them based on either β-tubulin or calmodulin sequence data. Aspergillus eucalypticola produced pyranonigrin A, funalenone, aurasperone B and other naphtho-γ-pyrones. Aspergillus neoniger is also a biseriate species isolated from desert sand in Namibia, and mangrove water in Venezuela, which produces aurasperone B and pyranonigrin A. Aspergillus fijiensis is a uniseriate species related to A. aculeatinus, and was isolated from soil in Fiji, and from Lactuca sativa in Indonesia. This species is able to grow at 37 °C, and produces asperparalines and okaramins. Aspergillus indologenus was isolated from soil, India. This species also belongs to the uniseriate group of black aspergilli, and was found to be related to, but clearly distinguishable from A. uvarum based on β-tubulin, calmodulin and ITS sequence data. Aspergillus indologenus produced the insecticidal compounds okaramins A, B, H, and two types of indol-alkaloids which have not been structure elucidated. Two other species, A. violaceofuscus and A. acidus, are revalidated based on molecular and extrolite data. Aspergillus violaceofuscus was found to be related to A. japonicus, and produced some of the same interesting indol-alkaloids as A. indologenus, and also produced several families of partially characterised extrolites that were also found in A. heteromorphus. Aspergillus acidus (previously known as A. foetidus var. pallidus and A. foetidus var. acidus) is also a valid species, while A. foetidus is a synonym of A. niger based on molecular and physiological data. Two other species described previously, A. coreanus and A. lacticoffeatus, were found to be colour mutants of A. acidus and A. niger, respectively. Methods which could be used to distinguish the two closely related and economically important species A. niger and A. awamori are also detailed. Although these species differ in their occurrence and several physiological means (elastase activities, abilities to utilise 2-deoxy-D-glucose as sole carbon source), our data indicate that only molecular approaches including sequence analysis of calmodulin or β-tubulin genes, AFLP analysis, UP-PCR analysis or mtDNA RFLP analysis can be used reliably to distinguish these sibling species. Aspergillus section Nigri now includes 26 taxa.
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Affiliation(s)
- J. Varga
- CBS-KNAW Fungal Biodiversity Centre, Uppsalalaan 8, 3584 CT Utrecht, The Netherlands
- Department of Microbiology, Faculty of Science and Informatics, University of Szeged, H-6726 Szeged, Közép fasor 52, Hungary
- Correspondence: János Varga,
| | - J.C. Frisvad
- Center for Microbial Biotechnology, Department of Systems Biology-DTU, Søltofts Plads, Building 221, Technical University of Denmark, DK-2800 Kgs. Lyngby, Denmark
| | - S. Kocsubé
- Department of Microbiology, Faculty of Science and Informatics, University of Szeged, H-6726 Szeged, Közép fasor 52, Hungary
| | - B. Brankovics
- Department of Microbiology, Faculty of Science and Informatics, University of Szeged, H-6726 Szeged, Közép fasor 52, Hungary
| | - B. Tóth
- Cereal Research Non-Profit Ltd., H-6726 Szeged, Alsókikötő sor 9, Hungary
| | - G. Szigeti
- Department of Microbiology, Faculty of Science and Informatics, University of Szeged, H-6726 Szeged, Közép fasor 52, Hungary
| | - R.A. Samson
- CBS-KNAW Fungal Biodiversity Centre, Uppsalalaan 8, 3584 CT Utrecht, The Netherlands
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Mogensen JM, Sørensen SM, Sulyok M, van der Westhuizen L, Shephard GS, Frisvad JC, Thrane U, Krska R, Nielsen KF. Single-kernel analysis of fumonisins and other fungal metabolites in maize from South African subsistence farmers. Food Addit Contam Part A Chem Anal Control Expo Risk Assess 2011; 28:1724-34. [PMID: 22023397 DOI: 10.1080/19440049.2011.611823] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
Abstract
Fumonisins are important Fusarium mycotoxins mainly found in maize and derived products. This study analysed maize from five subsistence farmers in the former Transkei region of South Africa. Farmers had sorted kernels into good and mouldy quality. A total of 400 kernels from 10 batches were analysed; of these 100 were visually characterised as uninfected and 300 as infected. Of the 400 kernels, 15% were contaminated with 1.84-1428 mg kg(-1) fumonisins, and 4% (n=15) had a fumonisin content above 100 mg kg(-1). None of the visually uninfected maize had detectable amounts of fumonisins. The total fumonisin concentration was 0.28-1.1 mg kg(-1) for good-quality batches and 0.03-6.2 mg kg(-1) for mouldy-quality batches. The high fumonisin content in the batches was apparently caused by a small number (4%) of highly contaminated kernels, and removal of these reduced the average fumonisin content by 71%. Of the 400 kernels, 80 were screened for 186 microbial metabolites by liquid chromatography-tandem mass spectrometry, detecting 17 other fungal metabolites, including fusaric acid, equisetin, fusaproliferin, beauvericin, cyclosporins, agroclavine, chanoclavine, rugulosin and emodin. Fusaric acid in samples without fumonisins indicated the possibility of using non-toxinogenic Fusaria as biocontrol agents to reduce fumonisin exposure, as done for Aspergillus flavus. This is the first report of mycotoxin profiling in single naturally infected maize kernels.
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Affiliation(s)
- J M Mogensen
- Center for Microbial Biotechnology, Department of Systems Biology, Technical University of Denmark, Søltofts Plads 221, DK-2800 Kgs. Lyngby, Denmark
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Howard SJ, Harrison E, Bowyer P, Varga J, Denning DW. Cryptic species and azole resistance in the Aspergillus niger complex. Antimicrob Agents Chemother 2011; 55:4802-9. [PMID: 21768508 PMCID: PMC3186969 DOI: 10.1128/aac.00304-11] [Citation(s) in RCA: 97] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2011] [Accepted: 07/11/2011] [Indexed: 11/20/2022] Open
Abstract
Aspergillus niger is a common clinical isolate. Multiple species comprise the Aspergillus section Nigri and are separable using sequence data. The antifungal susceptibility of these cryptic species is not known. We determined the azole MICs of 50 black aspergilli, 45 from clinical specimens, using modified EUCAST (mEUCAST) and Etest methods. Phylogenetic trees were prepared using the internal transcribed spacer, beta-tubulin, and calmodulin sequences to identify strains to species level and the results were compared with those obtained with cyp51A sequences. We attempted to correlate cyp51A mutations with azole resistance. Etest MICs were significantly different from mEUCAST MICs (P < 0.001), with geometric means of 0.77 and 2.79 mg/liter, respectively. Twenty-six of 50 (52%) isolates were itraconazole resistant by mEUCAST (MICs > 8 mg/liter), with limited cross-resistance to other azoles. Using combined beta-tubulin/calmodulin sequences, the 45 clinical isolates grouped into 5 clades, A. awamori (55.6%), A. tubingensis (17.8%), A. niger (13.3%), A. acidus (6.7%), and an unknown group (6.7%), none of which were morphologically distinguishable. Itraconazole resistance was found in 36% of the isolates in the A. awamori group, 90% of the A. tubingensis group, 33% of the A. niger group, 100% of the A. acidus group, and 67% of the unknown group. These data suggest that cyp51A mutations in section Nigri may not play as important a role in azole resistance as in A. fumigatus, although some mutations (G427S, K97T) warrant further study. Numerous cryptic species are found in clinical isolates of the Aspergillus section Nigri and are best reported as "A. niger complex" by clinical laboratories. Itraconazole resistance was common in this data set, but azole cross-resistance was unusual. The mechanism of resistance remains obscure.
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Affiliation(s)
- Susan J Howard
- The University of Manchester, 1.800 Stopford Building, Oxford Road, Manchester M13 9PT, United Kingdom.
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Tóth V, Nagy CT, Miskei M, Pócsi I, Emri T. Polyphasic characterization of "Aspergillus nidulans var. roseus" ATCC 58397. Folia Microbiol (Praha) 2011; 56:381-8. [PMID: 21858538 DOI: 10.1007/s12223-011-0059-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2011] [Accepted: 07/14/2011] [Indexed: 11/24/2022]
Abstract
Polyphasic characterization of the echinocandin B producer Aspergillus nidulans var. roseus ATCC 58397 strain was carried out to elucidate its taxonomical status. According to its carbon source utilization and secondary metabolite spectrum as well as the partial β-tubulin, calmodulin, and γ-actin gene sequences, A. nidulans var. roseus belongs to the Emericella rugulosa species. Auxotroph mutants of A. nidulans var. roseus ATCC 58397 and E. rugulosa CBS 171.71 and CBS 133.60 formed stable heterokaryons on minimal medium with several A. nidulans strains, and in the case of A. nidulans var. roseus, even cleistothecia were developed.
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Affiliation(s)
- Viktória Tóth
- Department of Microbial Biotechnology and Cell Biology, Faculty of Science and Technology, University of Debrecen, Egyetem tér 1, 4032, Debrecen, Hungary
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Development of a Real Time PCR system for detection of ochratoxin A-producing strains of the Aspergillus niger aggregate. Food Control 2011. [DOI: 10.1016/j.foodcont.2011.02.014] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Davolos D, Persiani AM, Pietrangeli B, Ricelli A, Maggi O. Aspergillus affinis sp. nov., a novel ochratoxin A-producing Aspergillus species (section Circumdati) isolated from decomposing leaves. Int J Syst Evol Microbiol 2011; 62:1007-1015. [PMID: 21788229 DOI: 10.1099/ijs.0.034785-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Two ochratoxin A (OTA)-producing Aspergillus isolates, recently collected from submerged riparian decomposing leaves in Italy, were found to have a similar morphology to Aspergillus cretensis (subgenus Circumdati, section Circumdati). However, marked differences emerged between these two novel isolates and A. cretensis as the former displayed different colony features and had larger vesicles, metulae, phialides and conidia, as well as a distinct sclerotial form and size. In order to determine the taxonomic status and to infer the evolutionary relationships of these two morphologically identical isolates, a molecular phylogenetic analysis was performed on all the officially recognized lineages in the section Circumdati. The DNA sequences and the deduced amino acid residues from the nuclear loci were analysed. Both rRNA and protein coding genes were assessed, which are widely used to differentiate taxa belonging to genus Aspergillus at various evolutionary levels. The 5.8S rDNA gene and internal transcribed spacers (ITS), the D1/D2 domains of the 28S rDNA gene, a region of the tubulin beta chain gene (benA) and part of the calmodulin gene (cmd) were amplified by PCR and then sequenced. The analysis of the rRNA regions and of the benA and cmd sequence data indicated that the two isogenic isolates belonged to a genetically distinct OTA-producing species of the genus Aspergillus. The isolates are proposed as representing a novel species, Aspergillus affinis sp. nov., with the type strain ATCC MYA-4773T=CBS 129190=417). Phylogenetically, A. affinis sp. nov. appeared to be very closely related to A. cretensis, from which it could be distinguished by means of a morphological trait analysis.
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Affiliation(s)
- Domenico Davolos
- Department of Productive Plants and Interaction with the Environment (DIPIA), National Institute for Occupational Safety and Prevention (INAIL-exISPESL), Via Urbana, 167 - 00184 Rome, Italy
| | - Anna Maria Persiani
- Department of Environmental Biology, Sapienza University of Rome, P. le A. Moro, 5-00185 Rome, Italy
| | - Biancamaria Pietrangeli
- Department of Productive Plants and Interaction with the Environment (DIPIA), National Institute for Occupational Safety and Prevention (INAIL-exISPESL), Via Urbana, 167 - 00184 Rome, Italy
| | - Alessandra Ricelli
- Institute of Biomolecular Chemistry ICB-CNR, P. le A. Moro, 5 - 00185 Rome, Italy
| | - Oriana Maggi
- Department of Environmental Biology, Sapienza University of Rome, P. le A. Moro, 5-00185 Rome, Italy
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Samson RA, Noonim P, Meijer M, Houbraken J, Frisvad JC, Varga J. Diagnostic tools to identify black aspergilli. Stud Mycol 2011; 59:129-45. [PMID: 18490945 PMCID: PMC2275192 DOI: 10.3114/sim.2007.59.13] [Citation(s) in RCA: 211] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
The present taxonomy of the black aspergilli reveals that there are 19
accepted taxa. However the identification of species of Aspergillus
section Nigri is often problematic in spite of the existence of
numerous methods proposed. An overview is provided of phenotypic and molecular
methods to identify the accepted species of the black aspergilli. Colony
morphology, conidial size and ornamentation of the ex type cultures is
presented in a pictorial overview. The temperature range of all species is
given and their growth characteristics on creatine agar and boscalid agar, a
medium which was developed as a selective medium for the isolation of A.
carbonarius are also shown. The extrolites produced by each species are
listed while the response of the Ehrlich reaction is described. The literature
on the various molecular methods to be used for species identification is
reviewed and a critical evaluation of the usefulness of various techniques and
genomic loci for species identification of black aspergilli is presented.
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Affiliation(s)
- R A Samson
- CBS Fungal Biodiversity Centre, Uppsalalaan 8, 3584 CT Utrecht, The Netherlands
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75
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Andersen MR, Salazar MP, Schaap PJ, van de Vondervoort PJI, Culley D, Thykaer J, Frisvad JC, Nielsen KF, Albang R, Albermann K, Berka RM, Braus GH, Braus-Stromeyer SA, Corrochano LM, Dai Z, van Dijck PWM, Hofmann G, Lasure LL, Magnuson JK, Menke H, Meijer M, Meijer SL, Nielsen JB, Nielsen ML, van Ooyen AJJ, Pel HJ, Poulsen L, Samson RA, Stam H, Tsang A, van den Brink JM, Atkins A, Aerts A, Shapiro H, Pangilinan J, Salamov A, Lou Y, Lindquist E, Lucas S, Grimwood J, Grigoriev IV, Kubicek CP, Martinez D, van Peij NNME, Roubos JA, Nielsen J, Baker SE. Comparative genomics of citric-acid-producing Aspergillus niger ATCC 1015 versus enzyme-producing CBS 513.88. Genome Res 2011; 21:885-97. [PMID: 21543515 DOI: 10.1101/gr.112169.110] [Citation(s) in RCA: 266] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The filamentous fungus Aspergillus niger exhibits great diversity in its phenotype. It is found globally, both as marine and terrestrial strains, produces both organic acids and hydrolytic enzymes in high amounts, and some isolates exhibit pathogenicity. Although the genome of an industrial enzyme-producing A. niger strain (CBS 513.88) has already been sequenced, the versatility and diversity of this species compel additional exploration. We therefore undertook whole-genome sequencing of the acidogenic A. niger wild-type strain (ATCC 1015) and produced a genome sequence of very high quality. Only 15 gaps are present in the sequence, and half the telomeric regions have been elucidated. Moreover, sequence information from ATCC 1015 was used to improve the genome sequence of CBS 513.88. Chromosome-level comparisons uncovered several genome rearrangements, deletions, a clear case of strain-specific horizontal gene transfer, and identification of 0.8 Mb of novel sequence. Single nucleotide polymorphisms per kilobase (SNPs/kb) between the two strains were found to be exceptionally high (average: 7.8, maximum: 160 SNPs/kb). High variation within the species was confirmed with exo-metabolite profiling and phylogenetics. Detailed lists of alleles were generated, and genotypic differences were observed to accumulate in metabolic pathways essential to acid production and protein synthesis. A transcriptome analysis supported up-regulation of genes associated with biosynthesis of amino acids that are abundant in glucoamylase A, tRNA-synthases, and protein transporters in the protein producing CBS 513.88 strain. Our results and data sets from this integrative systems biology analysis resulted in a snapshot of fungal evolution and will support further optimization of cell factories based on filamentous fungi.
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Affiliation(s)
- Mikael R Andersen
- Center for Microbial Biotechnology, Department of Systems Biology, Technical University of Denmark, DK-2800 Kongens Lyngby, Denmark
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Roze LV, Chanda A, Laivenieks M, Beaudry RM, Artymovich KA, Koptina AV, Awad DW, Valeeva D, Jones AD, Linz JE. Volatile profiling reveals intracellular metabolic changes in Aspergillus parasiticus: veA regulates branched chain amino acid and ethanol metabolism. BMC BIOCHEMISTRY 2010; 11:33. [PMID: 20735852 PMCID: PMC2939540 DOI: 10.1186/1471-2091-11-33] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/02/2010] [Accepted: 08/24/2010] [Indexed: 01/17/2023]
Abstract
Background Filamentous fungi in the genus Aspergillus produce a variety of natural products, including aflatoxin, the most potent naturally occurring carcinogen known. Aflatoxin biosynthesis, one of the most highly characterized secondary metabolic pathways, offers a model system to study secondary metabolism in eukaryotes. To control or customize biosynthesis of natural products we must understand how secondary metabolism integrates into the overall cellular metabolic network. By applying a metabolomics approach we analyzed volatile compounds synthesized by Aspergillus parasiticus in an attempt to define the association of secondary metabolism with other metabolic and cellular processes. Results Volatile compounds were examined using solid phase microextraction - gas chromatography/mass spectrometry. In the wild type strain Aspergillus parasiticus SU-1, the largest group of volatiles included compounds derived from catabolism of branched chain amino acids (leucine, isoleucine, and valine); we also identified alcohols, esters, aldehydes, and lipid-derived volatiles. The number and quantity of the volatiles produced depended on media composition, time of incubation, and light-dark status. A block in aflatoxin biosynthesis or disruption of the global regulator veA affected the volatile profile. In addition to its multiple functions in secondary metabolism and development, VeA negatively regulated catabolism of branched chain amino acids and synthesis of ethanol at the transcriptional level thus playing a role in controlling carbon flow within the cell. Finally, we demonstrated that volatiles generated by a veA disruption mutant are part of the complex regulatory machinery that mediates the effects of VeA on asexual conidiation and sclerotia formation. Conclusions 1) Volatile profiling provides a rapid, effective, and powerful approach to identify changes in intracellular metabolic networks in filamentous fungi. 2) VeA coordinates the biosynthesis of secondary metabolites with catabolism of branched chain amino acids, alcohol biosynthesis, and β-oxidation of fatty acids. 3) Intracellular chemical development in A. parasiticus is linked to morphological development. 4) Understanding carbon flow through secondary metabolic pathways and catabolism of branched chain amino acids is essential for controlling and customizing production of natural products.
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Affiliation(s)
- Ludmila V Roze
- Department of Food Science and Human Nutrition, Michigan State University, East Lansing, MI, USA.
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Ehrlich KC, Chang PK, Scharfenstein LL, Cary JW, Crawford JM, Townsend CA. Absence of the aflatoxin biosynthesis gene, norA, allows accumulation of deoxyaflatoxin B1 in Aspergillus flavus cultures. FEMS Microbiol Lett 2010; 305:65-70. [PMID: 20158523 DOI: 10.1111/j.1574-6968.2010.01914.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Biosynthesis of the highly toxic and carcinogenic aflatoxins in select Aspergillus species from the common intermediate O-methylsterigmatocystin has been postulated to require only the cytochrome P450 monooxygenase, OrdA (AflQ). We now provide evidence that the aryl alcohol dehydrogenase NorA (AflE) encoded by the aflatoxin biosynthetic gene cluster in Aspergillus flavus affects the accumulation of aflatoxins in the final steps of aflatoxin biosynthesis. Mutants with inactive norA produced reduced quantities of aflatoxin B(1) (AFB(1)), but elevated quantities of a new metabolite, deoxyAFB(1). To explain this result, we suggest that, in the absence of NorA, the AFB(1) reduction product, aflatoxicol, is produced and is readily dehydrated to deoxyAFB(1) in the acidic medium, enabling us to observe this otherwise minor toxin produced in wild-type A. flavus.
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Affiliation(s)
- Kenneth C Ehrlich
- Southern Regional Research Center, ARS/USDA, New Orleans, LA 70179, USA.
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Triterpene chemosyndromes and subtle morphological characters characterise lineages in thePhyscia aipoliagroup in Australia (Ascomycota). SYST BIODIVERS 2009. [DOI: 10.1017/s1477200009990223] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Abstract
This review summarizes the health aspects of the medically important fungal genus Aspergillus. The morphology and systematics of the genus are explained as well as its biogeography. Major mycotoxins, the aspergilli that produce them, affected crops, and symptoms of the toxicoses are summarized, as are the major mycoses caused by aspergilli. The current status of the relationship between Aspergillus in the indoor environment and health issues are discussed.
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Affiliation(s)
- Maren A Klich
- USDA, ARS, Southern Regional Research Center, New Orleans, LA 70124, USA.
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Nielsen KF, Mogensen JM, Johansen M, Larsen TO, Frisvad JC. Review of secondary metabolites and mycotoxins from the Aspergillus niger group. Anal Bioanal Chem 2009; 395:1225-42. [PMID: 19756540 DOI: 10.1007/s00216-009-3081-5] [Citation(s) in RCA: 220] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2009] [Revised: 08/17/2009] [Accepted: 08/18/2009] [Indexed: 11/26/2022]
Abstract
Filamentous fungi in the Aspergillus section Nigri (the black aspergilli) represent some of the most widespread food and feed contaminants known but they are also some of the most important workhorses used by the biotechnological industry. The Nigri section consists of six commonly found species (excluding A. aculeatus and its close relatives) from which currently 145 different secondary metabolites have been isolated and/or detected. From a human and animal safety point of view, the mycotoxins ochratoxin A (from A. carbonarius and less frequently A. niger) and fumonisin B(2) (from A. niger) are currently the most problematic compounds. Especially in foods and feeds such as coffee, nuts, dried fruits, and grape-based products where fumonisin-producing fusaria are not a problem, fumonisins pose a risk. Moreover, compounds such as malformins, naptho-gamma-pyrones, and bicoumarins (kotanins) call for monitoring in food, feed, and biotechnology products as well as for a better toxicological evaluation, since they are often produced in large amounts by the black aspergilli. For chemical differentiation/identification of the less toxic species the diketopiperazine asperazine can be used as a positive marker since it is consistently produced by A. tubingensis (177 of 177 strains tested) and A. acidus (47 of 47 strains tested) but never by A. niger (140 strains tested). Naptho-gamma-pyrones are the compounds produced in the highest quantities and are produced by all six common species in the group (A. niger 134 of 140; A. tubingensis 169 of 177; A. acidus 44 of 47; A. carbonarius 40 of 40, A. brasiliensis 18 of 18; and A. ibericus three of three).
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Affiliation(s)
- Kristian Fog Nielsen
- Center for Microbial Biotechnology, Department of Systems Biology, Technical University of Denmark, Søltofts Plads 221, 2800 Kgs, Lyngby, Denmark
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Murillo C, Albertazzi FJ, Carranza J, Lumbsch HT, Tamayo G. Molecular data indicate that Rhytidhysteron rufulum (ascomycetes, Patellariales) in Costa Rica consists of four distinct lineages corroborated by morphological and chemical characters. ACTA ACUST UNITED AC 2008; 113:405-16. [PMID: 18930137 DOI: 10.1016/j.mycres.2008.09.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2008] [Revised: 06/26/2008] [Accepted: 09/04/2008] [Indexed: 11/27/2022]
Abstract
Rhytidhysteron rufulum is a poorly known, common, pantropical species, capable of utilizing different substrata and occupying diverse habitats, and is the only species of its genus in Costa Rica. We have employed molecular, morphological, and chemical data to assess the variability and differentiation of R. rufulum in Costa Rica, including sites from the Pacific and Atlantic coast. Phylogenetic analyses of nuclear ITS rDNA sequences revealed the presence of four distinct lineages in the R. rufulum complex. Re-examination of the morphology and anatomy showed differences between these lineages in ascomatal, ascal, and ascospore size that have previously been regarded as intraspecific variations. In addition, there was a correlation between molecular phylogenies and chemical components as determined by hplc and nuclear magnetic resonance (NMR). Two lineages (clades I and II) produced the palmarumycins MK-3018, CJ-12372, and CR(1), whereas clade III produced dehydrocurvularin, and clade IV unidentified compounds. Our results based on a polyphasic approach contradict previous taxonomic interpretations of one morphologically variable species.
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Affiliation(s)
- Catalina Murillo
- Unidad Estratégica de Bioprospección, Instituto Nacional de Biodiversidad (INBio), 22-3100 Santo Domingo de Heredia, Costa Rica.
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Occurrence of Penicillium verrucosum in retail wheat flours from the Spanish market. Food Microbiol 2008; 25:642-7. [DOI: 10.1016/j.fm.2008.04.003] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2008] [Revised: 04/08/2008] [Accepted: 04/10/2008] [Indexed: 11/19/2022]
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