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Boruta T, Górnicka A, Grzybowska I, Stefaniak I, Bizukojć M. Exploring the extremes: applying high concentration of yeast extract leads to drastic morphological changes and elimination of (+)-geodin and asterric acid production in Aspergillus terreus submerged cultures. Biotechnol Lett 2020; 43:61-71. [PMID: 33026584 PMCID: PMC7796888 DOI: 10.1007/s10529-020-03018-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Accepted: 09/29/2020] [Indexed: 11/25/2022]
Abstract
Objective Evaluation of morphology and secondary metabolites production in Aspergillus terreus ATCC 20542 cultures over a wide range of lactose and yeast extract concentrations from 0.2 up to an extremely high level of 200 g l−l. Results The morphological differences of mycelial objects were quantified with the use of morphological parameters calculated by applying the tools of digital image analysis. At 200 g l−l of yeast extract clumps and loose hyphae were recorded instead of pellets commonly observed in submerged cultures of A. terreus. Under these conditions the biosynthesis of (+)-geodin and asterric acid was totally blocked, lovastatin formation was found to be at a relatively low level and biomass production turned out to be greater than in the remaining variants, where the pelleted growth was observed. At 200 g l−l of lactose the production of lovastatin, (+)-geodin and asterric acid was visibly stimulated compared to the media containing 0.2, 2 and 20 g l−l of the sugar substrate, but at the same time no traces of butyrolactone I could be detected in the broth. Lactose at the extremely high concentration of 200 g l−l did not induce the drastic morphological changes observed in the case of 200 g l-1 of yeast extract. It was proved that at the C/N values as low as 4 and as high as 374 A. terreus not only continued to display growth but also exhibited the production of secondary metabolites. The use of cultivation media representing the equivalent C/N ratios led to different metabolic and morphological outcomes depending on the concentration of lactose and yeast extract that contributed to the given C/N value. Conclusion The extremely high concentration of yeast extract leads to marked morphological changes of A. terreus and the elimination of (+)-geodin and asterric production, while applying the excess of lactose is stimulatory in terms of lovastatin production. Electronic supplementry material The online version of this article (10.1007/s10529-020-03018-5) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Tomasz Boruta
- Faculty of Process and Environmental Engineering, Department of Bioprocess Engineering, Lodz University of Technology, ul. Wolczanska 213, 90-924, Lodz, Poland.
| | - Adrianna Górnicka
- Faculty of Process and Environmental Engineering, Department of Bioprocess Engineering, Lodz University of Technology, ul. Wolczanska 213, 90-924, Lodz, Poland
| | - Iwona Grzybowska
- Faculty of Process and Environmental Engineering, Department of Bioprocess Engineering, Lodz University of Technology, ul. Wolczanska 213, 90-924, Lodz, Poland
| | - Ida Stefaniak
- Faculty of Process and Environmental Engineering, Department of Bioprocess Engineering, Lodz University of Technology, ul. Wolczanska 213, 90-924, Lodz, Poland
| | - Marcin Bizukojć
- Faculty of Process and Environmental Engineering, Department of Bioprocess Engineering, Lodz University of Technology, ul. Wolczanska 213, 90-924, Lodz, Poland
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Mathimaran A, Kumar A. Changes in morphogenesis and carotenogenesis to influence polygalacturonase secretion in Aspergillus carbonarius mutant. Arch Microbiol 2020; 202:1285-1293. [PMID: 32128608 DOI: 10.1007/s00203-020-01838-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2020] [Revised: 01/31/2020] [Accepted: 02/14/2020] [Indexed: 01/09/2023]
Abstract
Mycelial morphogenesis and the production of fungal secretory proteins are still largely unknown. A mutant strain of Aspergillus carbonarius UV-10046 produced abundant polygalacturonase (PG) along with partially saturated canthaxanthin (PSC) at low pH conditions. In the present study, the relationship between PG secretion and PSC biosynthesis was studied using carotenogenic inhibitors and SDS-PAGE electrophoresis. Also the correlation between morphogenesis and PG secretion was investigated by analysing through microscopic studies. From the results, it was observed that secretion of PG was positively influenced by the PSC biosynthesis. The results also showed that the mutant with hairy mycelial structure resulted in higher PG activity when compared to the wild type that lacks hyper branching. From the results, it was confirmed that a mutation might have occurred in the isoprenoid pathway that has helped mutant for survival at acidic conditions. Further, an alteration in the morphogenesis and hyper branching development caused over secretion of PG enzyme in the mutant.
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Affiliation(s)
- Ahila Mathimaran
- Department of Biotechnology, Periyar Maniammai Institute of Science & Technology, Vallam, Thanjavur, Tamil Nadu, 613403, India
| | - Anbarasu Kumar
- Department of Biotechnology, Periyar Maniammai Institute of Science & Technology, Vallam, Thanjavur, Tamil Nadu, 613403, India.
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Carvajal-Campos A, Manizan AL, Tadrist S, Akaki DK, Koffi-Nevry R, Moore GG, Fapohunda SO, Bailly S, Montet D, Oswald IP, Lorber S, Brabet C, Puel O. Aspergillus korhogoensis, a Novel Aflatoxin Producing Species from the Côte d'Ivoire. Toxins (Basel) 2017; 9:E353. [PMID: 29088078 PMCID: PMC5705968 DOI: 10.3390/toxins9110353] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2017] [Revised: 10/13/2017] [Accepted: 10/26/2017] [Indexed: 12/12/2022] Open
Abstract
Several strains of a new aflatoxigenic species of Aspergillus, A. korhogoensis, were isolated in the course of a screening study involving species from section Flavi found contaminating peanuts (Arachis hypogaea) and peanut paste in the Côte d'Ivoire. Based on examination of four isolates, this new species is described using a polyphasic approach. A concatenated alignment comprised of nine genes (ITS, benA, cmdA, mcm7, amdS, rpb1, preB, ppgA, and preA) was subjected to phylogenetic analysis, and resulted in all four strains being inferred as a distinct clade. Characterization of mating type for each strain revealed A. korhogoensis as a heterothallic species, since three isolates exhibited a singular MAT1-1 locus and one isolate exhibited a singular MAT1-2 locus. Morphological and physiological characterizations were also performed based on their growth on various types of media. Their respective extrolite profiles were characterized using LC/HRMS, and showed that this new species is capable of producing B- and G-aflatoxins, aspergillic acid, cyclopiazonic acid, aflavarins, and asparasones, as well as other metabolites. Altogether, our results confirm the monophyly of A. korhogoensis, and strengthen its position in the A. flavus clade, as the sister taxon of A. parvisclerotigenus.
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Affiliation(s)
- Amaranta Carvajal-Campos
- Toxalim (Research Centre in Food Toxicology), Université de Toulouse, INRA, ENVT, INP-Purpan, UPS, 31027 Toulouse, France.
| | - Ama Lethicia Manizan
- Laboratoire de Biotechnologie et Microbiologie des Aliments, UFR des Sciences et Technologie des Aliments, Université Nangui Abrogoua, 02 BP 801 Abidjan, Côte d'Ivoire.
| | - Souria Tadrist
- Toxalim (Research Centre in Food Toxicology), Université de Toulouse, INRA, ENVT, INP-Purpan, UPS, 31027 Toulouse, France.
| | - David Koffi Akaki
- Laboratoire des Procédés Industriels de Synthèse, de l'Environnement et des Energies Nouvelles, Département Génie Chimique et Agro-alimentaire, Institut National Polytechnique Félix Houphouët-Boigny, BP 1313 Yamoussoukro, Côte d'Ivoire.
| | - Rose Koffi-Nevry
- Laboratoire de Biotechnologie et Microbiologie des Aliments, UFR des Sciences et Technologie des Aliments, Université Nangui Abrogoua, 02 BP 801 Abidjan, Côte d'Ivoire.
| | - Geromy G Moore
- Southern Regional Research Center, Agricultural Research Service, United States Department of Agriculture, New Orleans, LA 70179, USA.
| | - Stephen O Fapohunda
- Department of Microbiology, Babcock University, 23401 Ilishan Remo, Nigeria.
| | - Sylviane Bailly
- Toxalim (Research Centre in Food Toxicology), Université de Toulouse, INRA, ENVT, INP-Purpan, UPS, 31027 Toulouse, France.
| | - Didier Montet
- Centre de Coopération Internationale en Recherche Agronomique pour le Développement (CIRAD)-Département PERSYST-UMR QualiSud, 34398 Montpellier, France.
| | - Isabelle P Oswald
- Toxalim (Research Centre in Food Toxicology), Université de Toulouse, INRA, ENVT, INP-Purpan, UPS, 31027 Toulouse, France.
| | - Sophie Lorber
- Toxalim (Research Centre in Food Toxicology), Université de Toulouse, INRA, ENVT, INP-Purpan, UPS, 31027 Toulouse, France.
| | - Catherine Brabet
- Centre de Coopération Internationale en Recherche Agronomique pour le Développement (CIRAD)-Département PERSYST-UMR QualiSud, 34398 Montpellier, France.
| | - Olivier Puel
- Toxalim (Research Centre in Food Toxicology), Université de Toulouse, INRA, ENVT, INP-Purpan, UPS, 31027 Toulouse, France.
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Mohanty S, Ghosh S, Nayak S, Das AP. Bioleaching of manganese by Aspergillus sp. isolated from mining deposits. Chemosphere 2017; 172:302-309. [PMID: 28086158 DOI: 10.1016/j.chemosphere.2016.12.136] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2016] [Revised: 12/23/2016] [Accepted: 12/27/2016] [Indexed: 06/06/2023]
Abstract
A comprehensive study on fungus assisted bioleaching of manganese (Mn) was carried out to demonstrate Mn solubilization of collected low grade ore from mining deposits of Sanindipur, Odisha, India. A native fungal strain MSF 5 was isolated and identified as Aspergillus sp. by Inter Transcribed Spacer (ITS) sequencing. The identified strain revealed an elevated tolerance ability to Mn under varying optimizing conditions like initial pH (2, 3, 4, 5, 6, 7), carbon sources (dextrose, sucrose, fructose and glucose) and pulp density (2%, 3%, 4%, 5% and 6%). Bioleaching studies carried out under optimized conditions of 2% pulp density of Mn ore at pH 6, temperature 37 °C and carbon dosage (dextrose) resulted with 79% Mn recovery from the ore sample within 20 days. SEM-EDX characterization of the ore sample and leach residue was carried out and the micrographs demonstrated porous and coagulated precipitates scattered across the matrix. The corresponding approach of FTIR analysis regulating the Mn oxide formation shows a distinctive peak of mycelium cells with and without treated Mn, resulting with generalized vibrations like MnOx stretching and CH2 stretch. Thus, our investigation endeavors' the considerate possible mechanism involved in fungal surface cells onto Mn ore illustrating an alteration in cellular Mn interaction.
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Affiliation(s)
- Sansuta Mohanty
- Bioengineering & Biomineral Processing Laboratory, Centre of Biotechnology, Siksha O Anusandhan University, Khandagiri Square, Bhubaneswar, India
| | - Shreya Ghosh
- Bioengineering & Biomineral Processing Laboratory, Centre of Biotechnology, Siksha O Anusandhan University, Khandagiri Square, Bhubaneswar, India
| | - Sanghamitra Nayak
- Bioengineering & Biomineral Processing Laboratory, Centre of Biotechnology, Siksha O Anusandhan University, Khandagiri Square, Bhubaneswar, India
| | - Alok Prasad Das
- Department of Chemical and Polymer Engineering, Tripura University (A Central University), Suryamaninagar, Tripura, India.
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Despot DJ, Kocsubé S, Bencsik O, Kecskeméti A, Szekeres A, Vágvölgyi C, Varga J, Klarić MŠ. Species diversity and cytotoxic potency of airborne sterigmatocystin-producing Aspergilli from the section Versicolores. Sci Total Environ 2016; 562:296-304. [PMID: 27100010 DOI: 10.1016/j.scitotenv.2016.03.183] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2016] [Revised: 03/24/2016] [Accepted: 03/25/2016] [Indexed: 06/05/2023]
Abstract
This study presents the distribution and species diversity of sterigmatocystin-producing Aspergilli from the section Versicolores in the indoor air of apartment-AP, basements-BS and grain mill-GM in Croatia, as well as the cytotoxic potency of isolates. The species comprised 0.7-20% of total airborne fungi detected in the AP, 11-55% in the BS, and 0-2% in the GM. Based on CaM sequences, seven species were identified; dominant were Aspergillus jensenii and Aspergillus creber, followed by Aspergillus protuberus, Aspergillus venenatus, Aspergillus tennesseensis, Aspergillus amoenus, Aspergillus griseoaurantiacus and three undescribed species. All of the identified species produced sterigmatocystin-STC (HPLC/UV-VIS); A. griseoaurantiacus (208.29μg/mL) and A. jensenii (1.192-133.63μg/mL) produced the highest levels, the lowest were detected in A. protuberus and A. tennesseensis (0.117-2.749μg/mL). Lower species diversity was obtained in the GM due to overgrowth with more propulsive fungi. Relatively high STC levels (0.06-2.35μg/g) detected in 52% of GM dust samples confirmed the presence of STC-producers, although this STC cannot be exclusively attributed to Aspergilli (Versicolores). STC and the majority of STC-producing Aspergilli were cytotoxic to human lung A549 cells (IC50 0.9-2.3μg/mL) and THP-1 macrophage-like cells (IC50 0.3-0.6μg/mL) in relatively low concentrations suggesting that humans can be at high risk during chronic exposure.
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Affiliation(s)
- Daniela Jakšić Despot
- Department of Microbiology, Faculty of Pharmacy and Biochemistry, University of Zagreb, Schrottova 39, 10000 Zagreb, Croatia
| | - Sandor Kocsubé
- Department of Microbiology, Faculty of Science and Informatics, University of Szeged, H-6726 Szeged, Közép fasor 52, Hungary
| | - Ottó Bencsik
- Department of Microbiology, Faculty of Science and Informatics, University of Szeged, H-6726 Szeged, Közép fasor 52, Hungary
| | - Anita Kecskeméti
- Department of Microbiology, Faculty of Science and Informatics, University of Szeged, H-6726 Szeged, Közép fasor 52, Hungary
| | - András Szekeres
- Department of Microbiology, Faculty of Science and Informatics, University of Szeged, H-6726 Szeged, Közép fasor 52, Hungary
| | - Csaba Vágvölgyi
- Department of Microbiology, Faculty of Science and Informatics, University of Szeged, H-6726 Szeged, Közép fasor 52, Hungary
| | - Janos Varga
- Department of Microbiology, Faculty of Science and Informatics, University of Szeged, H-6726 Szeged, Közép fasor 52, Hungary
| | - Maja Šegvić Klarić
- Department of Microbiology, Faculty of Pharmacy and Biochemistry, University of Zagreb, Schrottova 39, 10000 Zagreb, Croatia.
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Mangal M, Khan F, Bansal S, Oberoi HS. Validation of PCR based detection system for aflatoxin producing molds. Indian J Exp Biol 2016; 54:472-476. [PMID: 29466626] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Aflatoxins are polyketide secondary metabolites that are produced by certain fungal species in the Aspergillus section Flavi, particularly Aspergillus flavus and Aspergillus parasiticus which contaminate human food as well as animal feed. These are among the most carcinogenic substances known. Due to the toxic and carcinogenic properties of aflatoxins, there is a need to develop reliable methods to detect the presence of aflatoxigenic Aspergilli in contaminated food and feed. Not all Aspergillus strains are able to produce aflatoxins. It requires a detection methodology which can specifically distinguish between the aflatoxin producing and nonproducing strains of Aspergillus. Present communication reports validation of a PCR based detection system based on three genes viz., nor-1, apa-2 and omt-1 involved in aflatoxin biosynthesis, that can specifically distinguish the two aflatoxin producing species viz. Aspergillus flavus ,and Aspergillus parasiticus from non-producers i.e., A. niger, A. fumigates and A. oryzae.
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Tøndervik A, Sletta H, Klinkenberg G, Emanuel C, Powell LC, Pritchard MF, Khan S, Craine KM, Onsøyen E, Rye PD, Wright C, Thomas DW, Hill KE. Alginate oligosaccharides inhibit fungal cell growth and potentiate the activity of antifungals against Candida and Aspergillus spp. PLoS One 2014; 9:e112518. [PMID: 25409186 PMCID: PMC4237368 DOI: 10.1371/journal.pone.0112518] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2014] [Accepted: 10/03/2014] [Indexed: 12/24/2022] Open
Abstract
The oligosaccharide OligoG, an alginate derived from seaweed, has been shown to have anti-bacterial and anti-biofilm properties and potentiates the activity of selected antibiotics against multi-drug resistant bacteria. The ability of OligoG to perturb fungal growth and potentiate conventional antifungal agents was evaluated using a range of pathogenic fungal strains. Candida (n = 11) and Aspergillus (n = 3) spp. were tested using germ tube assays, LIVE/DEAD staining, scanning electron microscopy (SEM), atomic force microscopy (AFM) and high-throughput minimum inhibition concentration assays (MICs). In general, the strains tested showed a significant dose-dependent reduction in cell growth at ≥6% OligoG as measured by optical density (OD600; P<0.05). OligoG (>0.5%) also showed a significant inhibitory effect on hyphal growth in germ tube assays, although strain-dependent variations in efficacy were observed (P<0.05). SEM and AFM both showed that OligoG (≥2%) markedly disrupted fungal biofilm formation, both alone, and in combination with fluconazole. Cell surface roughness was also significantly increased by the combination treatment (P<0.001). High-throughput robotic MIC screening demonstrated the potentiating effects of OligoG (2, 6, 10%) with nystatin, amphotericin B, fluconazole, miconazole, voriconazole or terbinafine with the test strains. Potentiating effects were observed for the Aspergillus strains with all six antifungal agents, with an up to 16-fold (nystatin) reduction in MIC. Similarly, all the Candida spp. showed potentiation with nystatin (up to 16-fold) and fluconazole (up to 8-fold). These findings demonstrate the antifungal properties of OligoG and suggest a potential role in the management of fungal infections and possible reduction of antifungal toxicity.
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Affiliation(s)
- Anne Tøndervik
- Department of Bioprocess Technology, SINTEF Materials and Chemistry, N-7465 Trondheim, Norway
| | - Håvard Sletta
- Department of Bioprocess Technology, SINTEF Materials and Chemistry, N-7465 Trondheim, Norway
- * E-mail:
| | - Geir Klinkenberg
- Department of Bioprocess Technology, SINTEF Materials and Chemistry, N-7465 Trondheim, Norway
| | - Charlotte Emanuel
- Advanced Therapies Group, Tissue Engineering and Reparative Dentistry, Cardiff University School of Dentistry, Cardiff, CF14 4XY, United Kingdom
| | - Lydia C. Powell
- Advanced Therapies Group, Tissue Engineering and Reparative Dentistry, Cardiff University School of Dentistry, Cardiff, CF14 4XY, United Kingdom
| | - Manon F. Pritchard
- Advanced Therapies Group, Tissue Engineering and Reparative Dentistry, Cardiff University School of Dentistry, Cardiff, CF14 4XY, United Kingdom
| | - Saira Khan
- Advanced Therapies Group, Tissue Engineering and Reparative Dentistry, Cardiff University School of Dentistry, Cardiff, CF14 4XY, United Kingdom
| | - Kieron M. Craine
- Advanced Therapies Group, Tissue Engineering and Reparative Dentistry, Cardiff University School of Dentistry, Cardiff, CF14 4XY, United Kingdom
| | - Edvar Onsøyen
- AlgiPharma AS, Industriveien 33, N-1337 Sandvika, Norway
| | - Phil D. Rye
- AlgiPharma AS, Industriveien 33, N-1337 Sandvika, Norway
| | - Chris Wright
- Centre for NanoHealth, Systems and Process Engineering Centre, College of Engineering, Swansea University, Swansea, SA2 8PP, United Kingdom
| | - David W. Thomas
- Advanced Therapies Group, Tissue Engineering and Reparative Dentistry, Cardiff University School of Dentistry, Cardiff, CF14 4XY, United Kingdom
| | - Katja E. Hill
- Advanced Therapies Group, Tissue Engineering and Reparative Dentistry, Cardiff University School of Dentistry, Cardiff, CF14 4XY, United Kingdom
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Franco FP, Santiago AC, Henrique-Silva F, de Castro PA, Goldman GH, Moura DS, Silva-Filho MC. The sugarcane defense protein SUGARWIN2 causes cell death in Colletotrichum falcatum but not in non-pathogenic fungi. PLoS One 2014; 9:e91159. [PMID: 24608349 PMCID: PMC3946703 DOI: 10.1371/journal.pone.0091159] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2013] [Accepted: 02/10/2014] [Indexed: 11/18/2022] Open
Abstract
Plants respond to pathogens and insect attacks by inducing and accumulating a large set of defense-related proteins. Two homologues of a barley wound-inducible protein (BARWIN) have been characterized in sugarcane, SUGARWIN1 and SUGARWIN2 (sugarcane wound-inducible proteins). Induction of SUGARWINs occurs in response to Diatraea saccharalis damage but not to pathogen infection. In addition, the protein itself does not show any effect on insect development; instead, it has antimicrobial activities toward Fusarium verticillioides, an opportunistic fungus that usually occurs after D. saccharalis borer attacks on sugarcane. In this study, we sought to evaluate the specificity of SUGARWIN2 to better understand its mechanism of action against phytopathogens and the associations between fungi and insects that affect plants. We used Colletotrichum falcatum, a fungus that causes red rot disease in sugarcane fields infested by D. saccharalis, and Ceratocystis paradoxa, which causes pineapple disease in sugarcane. We also tested whether SUGARWIN2 is able to cause cell death in Aspergillus nidulans, a fungus that does not infect sugarcane, and in the model yeast Saccharomyces cerevisiae, which is used for bioethanol production. Recombinant SUGARWIN2 altered C. falcatum morphology by increasing vacuolization, points of fractures and a leak of intracellular material, leading to germling apoptosis. In C. paradoxa, SUGARWIN2 showed increased vacuolization in hyphae but did not kill the fungi. Neither the non-pathogenic fungus A. nidulans nor the yeast S. cerevisiae was affected by recombinant SUGARWIN2, suggesting that the protein is specific to sugarcane opportunistic fungal pathogens.
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Affiliation(s)
- Flávia P. Franco
- Departamento de Genética, Escola Superior de Agricultura Luiz de Queiroz, Universidade de São Paulo, Piracicaba, SP, Brazil
| | - Adelita C. Santiago
- Departamento de Genética e Evolução, Universidade Federal de São Carlos, São Carlos, SP, Brazil
| | - Flávio Henrique-Silva
- Departamento de Genética e Evolução, Universidade Federal de São Carlos, São Carlos, SP, Brazil
| | | | - Gustavo H. Goldman
- Faculdade de Ciências Farmacêuticas, Universidade de São Paulo, Ribeirão Preto, SP, Brazil
- Laboratório Nacional de Ciência e Tecnologia do Bioetanol (CTBE), Campinas, SP, Brazil
| | - Daniel S. Moura
- Departamento de Ciências Biológicas, Escola Superior de Agricultura Luiz de Queiroz, Universidade de São Paulo, Piracicaba, SP, Brazil
| | - Marcio C. Silva-Filho
- Departamento de Genética, Escola Superior de Agricultura Luiz de Queiroz, Universidade de São Paulo, Piracicaba, SP, Brazil
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Abstract
The taxonomy of fungal species, similar to that of many other microorganisms, suffers frequent revisions due to the discovery of new species and to the development and gathering of characterization data and morphological information. Morpho-taxonomy helps in the identification of many species. This work presents the macro, micro-morphological, and spectral mass analyses for phenotypic characterization of 13 species of Aspergillus section Nigri, showing that the characterization of spores (conidia) by scanning electron microscopy can be used as a tool to discriminate key morphological characteristics and separate closely related fungi. These results were corroborated by colony plates, stereomicroscopy, light microscopy, and spectral mass data.
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Affiliation(s)
- Marta Filipa Simões
- IBB-Institute for Biotechnology and Bioengineering, Centre of Biological Engineering, Universidade do Minho, Campus de Gualtar, 4710-057 Braga, Portugal
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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 Res Int 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] [What about the content of this article? (0)] [Affiliation(s)] [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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Maciel M, Ottoni C, Santos C, Lima N, Moreira K, Souza-Motta C. Production of polygalacturonases by Aspergillus section Nigri strains in a fixed bed reactor. Molecules 2013; 18:1660-71. [PMID: 23358324 PMCID: PMC6269776 DOI: 10.3390/molecules18021660] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2012] [Revised: 01/09/2013] [Accepted: 01/11/2013] [Indexed: 11/16/2022] Open
Abstract
Polygalacturonases (PG) are pectinolytic enzymes that have technological, functional and biological applications in food processing, fruit ripening and plant-fungus interactions, respectively. In the present, a microtitre plate methodology was used for rapid screening of 61 isolates of fungi from Aspergillus section Nigri to assess production of endo- and exo-PG. Studies of scale-up were carried out in a fixed bed reactor operated under different parameters using the best producer strain immobilised in orange peels. Four experiments were conducted under the following conditions: the immobilised cells without aeration; immobilised cells with aeration; immobilised cells with aeration and added pectin; and free cells with aeration. The fermentation was performed for 168 h with removal of sample every 24 h. Aspergillus niger strain URM 5162 showed the highest PG production. The results obtained indicated that the maximum endo- and exo-PG activities (1.18 U·mL−1 and 4.11 U·mL−1, respectively) were obtained when the reactor was operating without aeration. The microtitre plate method is a simple way to screen fungal isolates for PG activity detection. The fixed bed reactor with orange peel support and using A. niger URM 5162 is a promising process for PG production at the industrial level.
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Affiliation(s)
- Marília Maciel
- Mycology Department, Federal University of Pernambuco, Cidade Universitária, Recife 50670-420, Pernambuco, Brazil; E-Mail:
- IBB-Institute for Biotechnology and Bioengineering, Centre of Biological Engineering, Micoteca da Universidade do Minho, University of Minho, Campus of Gualtar, Braga 4710-057, Portugal; E-Mails: (C.O.); (C.S.); (N.L.)
| | - Cristiane Ottoni
- IBB-Institute for Biotechnology and Bioengineering, Centre of Biological Engineering, Micoteca da Universidade do Minho, University of Minho, Campus of Gualtar, Braga 4710-057, Portugal; E-Mails: (C.O.); (C.S.); (N.L.)
| | - Cledir Santos
- IBB-Institute for Biotechnology and Bioengineering, Centre of Biological Engineering, Micoteca da Universidade do Minho, University of Minho, Campus of Gualtar, Braga 4710-057, Portugal; E-Mails: (C.O.); (C.S.); (N.L.)
| | - Nelson Lima
- IBB-Institute for Biotechnology and Bioengineering, Centre of Biological Engineering, Micoteca da Universidade do Minho, University of Minho, Campus of Gualtar, Braga 4710-057, Portugal; E-Mails: (C.O.); (C.S.); (N.L.)
| | - Keila Moreira
- Academic Unit of Garanhuns, Federal Rural University of Pernambuco, Garanhuns 55292-270, Pernambuco, Brazil; E-Mail:
| | - Cristina Souza-Motta
- Mycology Department, Federal University of Pernambuco, Cidade Universitária, Recife 50670-420, Pernambuco, Brazil; E-Mail:
- Author to whom correspondence should be addressed; E-Mail: ; Tel.: +55-81-2126-8948; Fax: +55-81-2126-8480
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12
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Diao M, Yao M. Use of zero-valent iron nanoparticles in inactivating microbes. Water Res 2009; 43:5243-51. [PMID: 19783027 DOI: 10.1016/j.watres.2009.08.051] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2009] [Revised: 08/20/2009] [Accepted: 08/26/2009] [Indexed: 05/11/2023]
Abstract
Nanoscale zero-valent iron (NZVI) particles were investigated in inactivating gram-positive Bacillus subtilis var. niger and gram-negative Pseudomonas fluorescens bacteria, and the fungus Aspergillus versicolor. NZVI particles were synthesized using NaBH(4) and Fe(NO(3))(3).9H(2)O, and the microbial suspensions were subjected to the treatments of NZVI particle suspensions with concentrations of 0.1, 1 and 10mg/ml for 5min. Field emission scanning electron microscope (FE-SEM) was used to characterize the synthesized NZVI particles, suspensions and the surface morphologies of the treated agents. FE-SEM images showed that the NZVI particles were spherical with a fairly uniform size of about 20-30nm, and the iron precipitates FeO(OH) appeared in needle-shape aggregates. When treated directly with NZVI particles under aerobic condition, the surfaces of microbes were quickly coated with needle-shape yellow-brown iron oxides. In this study, complete inactivation was achieved both for B. subtilis var. niger and P. fluorescens when treated with 10mg/ml NZVI particles with vigorous shaking under aerobic condition. When NZVI particle concentration decreased to 1, 0.1mg/ml, there was still a complete inactivation for P. fluorescens, while for B. subtilis var. niger the inactivation decreased to 95%, 80%, respectively. However, no inactivation was observed for the fungus A. versicolor when treated the same manner. Physical coating, disruption of membrane and generation of reactive oxygen species have played major roles in the inactivation observed.
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Affiliation(s)
- Minghui Diao
- State Key Joint Laboratory of Environmental Simulation and Pollution Control College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
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13
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Doster MA, Cotty PJ, Michailides TJ. Description of a Distinctive Aflatoxin-Producing Strain of Aspergillus nomius that Produces Submerged Sclerotia. Mycopathologia 2009; 168:193-201. [PMID: 19484504 DOI: 10.1007/s11046-009-9214-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2008] [Accepted: 05/14/2009] [Indexed: 11/24/2022]
Affiliation(s)
- Mark A Doster
- Department of Plant Pathology, University of California, Davis/Kearney Agricultural Center, Parlier, CA 93648, USA.
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14
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Abstract
We report a case of onychomycosis caused by Aspergillus versicolor in a 66-year-old female patient. The infection was characterised clinically by yellowish pigmentation of the nail plate and mild nail bed hyperkeratosis of the first left toe. All other nails were normal. Three direct microscopical examinations of nail samples revealed the presence of hyaline hyphae as well as conidiophores. Pure colonies of A. versicolor were found in three cultures. The patient was successfully treated with oral itraconazole.
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15
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Selcuk M, Oksuz L, Basaran P. Decontamination of grains and legumes infected with Aspergillus spp. and Penicillum spp. by cold plasma treatment. Bioresour Technol 2008; 99:5104-9. [PMID: 17993274 DOI: 10.1016/j.biortech.2007.09.076] [Citation(s) in RCA: 150] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/09/2007] [Revised: 09/11/2007] [Accepted: 09/17/2007] [Indexed: 05/09/2023]
Abstract
The objective of this study was to determine the efficacy of a self-designed low pressure cold plasma (LPCP) system using air gases or SF6. For the inactivation and/or elimination of two pathogenic fungi, Aspergillus spp. and Penicillum spp. artificially contaminated on seed surface. The plasma decontamination process was performed by batch process in vacuum chamber, using gas injection followed by plasma discharge for the duration of 5-20 min. The plasma treatment reduced the fungal attachment to seeds below 1% of initial load depending on the initial contamination level, while preserving germination quality of the seed. A significant reduction of 3-log for both species was achieved within 15 min of SF6 plasma treatment time. Air gases plasma and SF6 plasma in particular provides an interesting surface decontamination alternative for seeds.
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Affiliation(s)
- Meral Selcuk
- Department of Food Engineering, Suleyman Demirel University, Isparta, Turkey
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16
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Ahearm DG, Price D, Simmons RB, Mayo A, Zhang ST, Crow SA. Microcycle conidiation and medusa head conidiophores of aspergilli on indoor construction materials and air filters from hospitals. Mycologia 2007; 99:1-6. [PMID: 17663117 DOI: 10.3852/mycologia.99.1.1] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Microcycle conidiation and microniche colonization by aspergilli was observed in-situ on various indoor construction and finishing materials. Microcycle conidiation, direct conidiogenesis from a conidium or spore with minimal intervening hyphal development, for several decades has been considered a survival mechanism during stress for a variety of moulds. Adhesive transparent tape mounts and bulk materials from various indoor materials, including air filters from hospitals and healthcare institutions, were transported to the laboratory for light microscopic and scanning electron microscopic observations. Additional materials were held in moist chambers over nonsterile soils and examined periodically for fungal development. Microcycle conidiation was observed usually in areas of sparse fungal development, mostly in association with isolations of members of the Aspergillus flavus-, A. versicolor-, A. niger groups. Branched conidiophores and medusa heads, more often associated with colonization by Eurotium spp., were observed on some preserved woods. These conidiogenesis processes might be factors in the survival and blooms of indoor aspergilli.
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Affiliation(s)
- D G Ahearm
- Center for Applied and Environmental Microbiology, Georgia State University, Atlanta, Georgia, USA.
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17
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Nguyen MH, Jaber R, Leather HL, Wingard JR, Staley B, Wheat LJ, Cline CL, Baz M, Rand KH, Clancy CJ. Use of bronchoalveolar lavage to detect galactomannan for diagnosis of pulmonary aspergillosis among nonimmunocompromised hosts. J Clin Microbiol 2007; 45:2787-92. [PMID: 17596367 PMCID: PMC2045248 DOI: 10.1128/jcm.00716-07] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Pulmonary aspergillosis in nonimmunocompromised hosts, although rare, is being increasingly recognized. The diagnosis of pulmonary aspergillosis is difficult, since the recovery of Aspergillus from respiratory samples cannot differentiate colonization from invasion. We assessed the role of bronchoalveolar lavage (BAL) in detecting galactomannan (GM) for diagnosing pulmonary aspergillosis in 73 nonimmunocompromised patients with pulmonary infiltrates for whom the test was ordered. Six patients had pulmonary aspergillosis, two each with acute invasive pulmonary aspergillosis, chronic necrotizing pulmonary aspergillosis, and aspergilloma. All six patients had a BAL GM level of >/=1.18. The sensitivity, specificity, and negative predictive value (NPV) for a BAL GM level of >/=1.0 were 100%, 88.1%, and 100%, respectively. Notably, the positive predictive value (PPV) was only 42.9%, likely reflecting the low prevalence of pulmonary aspergillosis among nonimmunosuppressed patients. The combination of BAL microscopy and culture had a sensitivity and NPV similar to those of BAL GM detection but a higher specificity and PPV (92.5% and 54.6%, respectively). Moreover, a BAL GM test did not identify any cases that were not diagnosed by conventional methods like microscopy and culture. In conclusion, there was no conclusive benefit of determining BAL GM levels in the diagnosis of pulmonary aspergillosis among nonimmunocompromised hosts. Given the likelihood of false-positive results, a BAL GM test should not be ordered routinely in this population.
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Affiliation(s)
- M Hong Nguyen
- Department of Medicine, University of Florida College of Medicine, Gainesville, Florida 32610, USA
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18
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Balajee SA, Lindsley MD, Iqbal N, Ito J, Pappas PG, Brandt ME. Nonsporulating clinical isolate identified as Petromyces alliaceus (anamorph Aspergillus alliaceus) by morphological and sequence-based methods. J Clin Microbiol 2007; 45:2701-3. [PMID: 17537938 PMCID: PMC1951206 DOI: 10.1128/jcm.00642-07] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Concerted morphological and sequencing-based strategies revealed the identity of a nonsporulating clinical isolate as Petromyces alliaceus (anamorph Aspergillus alliaceus). This rare Aspergillus sp. was recovered as the etiological agent of invasive pulmonary aspergillosis and had reduced in vitro susceptibilities to amphotericin B and caspofungin, which correlated with clinical failure of therapy.
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MESH Headings
- Amphotericin B/pharmacology
- Antifungal Agents/pharmacology
- Aspergillosis, Allergic Bronchopulmonary/drug therapy
- Aspergillosis, Allergic Bronchopulmonary/microbiology
- Aspergillus/cytology
- Aspergillus/drug effects
- Aspergillus/genetics
- Aspergillus/isolation & purification
- Caspofungin
- DNA, Fungal/chemistry
- DNA, Fungal/genetics
- DNA, Ribosomal/chemistry
- DNA, Ribosomal/genetics
- DNA, Ribosomal Spacer/chemistry
- DNA, Ribosomal Spacer/genetics
- Echinocandins
- Female
- Humans
- Lipopeptides
- Microbial Sensitivity Tests
- Middle Aged
- Molecular Sequence Data
- Peptides, Cyclic/pharmacology
- RNA, Ribosomal, 28S/genetics
- Sequence Analysis, DNA
- Sequence Homology, Nucleic Acid
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Affiliation(s)
- S Arunmozhi Balajee
- Mycotic Diseases Branch, Centers for Disease Control and Prevention, Mail Stop-G 11, 1600 Clifton Road, Atlanta, GA 30333, USA.
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19
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Juhász A, Engi H, Pfeiffer I, Kucsera J, Vágvölgyi C, Hamari Z. Interpretation of mtDNA RFLP variability among Aspergillus tubingensis isolates. Antonie Van Leeuwenhoek 2006; 91:209-16. [PMID: 17043909 DOI: 10.1007/s10482-006-9110-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2006] [Accepted: 07/25/2006] [Indexed: 10/24/2022]
Abstract
Aspergillus tubingensis isolates collected from distant geographic areas were earlier classified into six groups on the basis of the mtDNA RFLP variability they exhibited (mtDNA types 2a-2f). In the present work, we investigated the reason for the intraspecific mtDNA variability and we describe here how this fungus, with a relatively small mitochondrial genome, can display intraspecific polymorphism due to intron acquisition and also sporadic point mutations affecting the recognition motifs of the restriction enzymes employed in the RFLP analysis. Three different LAGLI-DADG type group I introns were identified in the cox1 gene amongst the six mtDNA RFLP types. MtDNAs of types 2b and 2d contain all of the three introns, mtDNA of type 2f carries only one, and the other mtDNA types contain two introns each. Comparative analysis showed that the first and second introns of mtDNAs of types 2b and 2d are well distributed among fungi, indicating their active horizontal transfer capacity. The third intron occurs rarely among fungi and is restricted to a limited number of fungal species, namely to A. tubingensis and the yeast Candida stellata. It is interesting that this intron is present in a small mitochondrial genome such as that of A. tubingensis and, considering its rarity, its presence amongst black Aspergillus isolates is recommended to be considered as a tool to establish taxonomical unit(s) or to track down evolutionary divergence of closely related taxonomical units.
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Affiliation(s)
- Akos Juhász
- Department of Microbiology, Faculty of Sciences, University of Szeged, P.O. Box 533, H-6701 Szeged, Hungary
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20
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Fomicheva GM, Vasilenko OV, Marfenina OE. [Comparative morphological, ecological, and molecular studies of Aspergillus versicolor (Vuill.) Tiraboschi strains isolated from different ecotopes]. Mikrobiologiia 2006; 75:228-34. [PMID: 16758871] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Cultural, morphological, ecological, and trophic properties (growth at different temperatures and on various organic substrates), as well as molecular and genetic peculiarities of Aspergillus versicolor (Vuill) Tiraboschi strains of different origins, were determined. The strains were isolated from different ecotopes (upper horizons of modern soils of several geographic regions, ancient soils and peat, and permafrost). No essential distinctions in cultural and morphological properties were revealed between the strains. Strains obtained from peat of the Aleutian Islands were characterized by the highest radial rates of colony growth. Some variations in the ITS loci of rDNA were observed in strains isolated from different ecotopes; the distinctions were most pronounced (1.7%) in the strain isolated from 100 000-year-old permafrost.
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21
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Porcel ER, López JLC, Ferrón MAV, Pérez JAS, Sánchez JLG, Chisti Y. Effects of the sporulation conditions on the lovastatin production by Aspergillus terreus. Bioprocess Biosyst Eng 2006; 29:1-5. [PMID: 16491374 DOI: 10.1007/s00449-006-0048-1] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2006] [Accepted: 01/23/2006] [Indexed: 11/30/2022]
Abstract
The production of biomass and lovastatin by spore-initiated submerged fermentations of Aspergillus terreus ATCC 20542 was shown to depend on the age of the spores used for inoculation. Cultures started from older spores produced significantly higher titers of lovastatin. For example, the lovastatin titer increased by 52% when the spore age at inoculation rose from 9 to 16 days. The lovastatin titer for a spore age of 16 days was 186.5+/-20.1 mg L(-1). The time to sporulation on surface cultures was sensitive to the light exposure history of the fungus and the spore inoculation concentration levels. A light exposure level of 140 muE m(-2 )s(-1) and a spore concentration of 1,320 spore cm(-2) produced the greatest extent of sporulation within about 50 h of inoculation. Sporulation was slowed in the dark and with diluted inoculants. A rigorous analysis of the data of statistically designed experiments showed the above observations to be highly reproducible.
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Affiliation(s)
- E Rodríguez Porcel
- Department of Chemical Engineering, University of Almería, 04120, Almería, Spain
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22
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Affiliation(s)
- Jessica S Kosut
- Department of Pediatrics, Children's National Medical Center, George Washington University School of Medicine and Health Sciences, Washington, DC, USA
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23
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Maggio-Hall LA, Wilson RA, Keller NP. Fundamental contribution of beta-oxidation to polyketide mycotoxin production in planta. Mol Plant Microbe Interact 2005; 18:783-93. [PMID: 16134890 DOI: 10.1094/mpmi-18-0783] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Seed contamination with polyketide mycotoxins, including aflatoxin (AF) and sterigmatocystin (ST) produced by Aspergillus spp., is an agricultural, economic, and medical issue worldwide. Acetyl-CoA, the fundamental building block of all known fungal polyketides, is generated by a large number of biochemical pathways, including beta-oxidation of fatty acids and glycolysis of sugars. We present several lines of evidence to support a major role for seed fatty acids in formation of AF and ST in A. flavus, A. parasiticus, and A. nidulans. Aspergillus strains exhibiting canonical signs of oleic acid-induced peroxisome proliferation, including increased catalase activity, beta-oxidation gene expression, and peroxisomal clustering, also exhibited a marked increase in toxin gene expression and biosynthesis. Furthermore, microscopic observations showed that the ST and AF precursor norsolorinic acid accumulated in peroxisomes of all three Aspergilli. While a peroxisomal beta-oxidation mutation eliminated oleic acid-induced increases in ST in A. nidulans, a mitochondrial beta-oxidation mutation played a larger role in eliminating ST formation on oatmeal medium and on live corn kernels, implicating a fundamental role for both peroxisomal and mitochondrial beta-oxidation in toxin production.
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Affiliation(s)
- Lori A Maggio-Hall
- Department of Plant Pathology, University of Wisconsin-Madison, 1630 Linden Drive, Madison, WI 53706, USA
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24
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de Vries RP, Frisvad JC, van de Vondervoort PJI, Burgers K, Kuijpers AFA, Samson RA, Visser J. Aspergillus vadensis, a new species of the group of black Aspergilli. Antonie Van Leeuwenhoek 2005; 87:195-203. [PMID: 15803385 DOI: 10.1007/s10482-004-3194-y] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2004] [Accepted: 09/13/2004] [Indexed: 11/24/2022]
Abstract
A strain from the group of black Aspergilli was analysed in detail to determine the species to which it belongs. A detailed analysis of morphology, RFLP patterns and metabolite profiles was carried out. In addition, a phylogenetic tree was constructed for the black Aspergilli using the ITS and the beta-tubulin sequences of the individual strains. The new species differs by its poor growth on glycerol and galacturonate and its unique extrolite profile consisting of aurasperone B, nigragillin, asperazine and kotanins. RFLP analysis using three genes as probes also resulted in a unique pattern. These data indicate that the strain was closely related but not identical to Aspergillus foetidus, Aspergillus niger and Aspergillus tubingensis. It was therefore designated as a novel species and named Aspergillus vadensis.
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Affiliation(s)
- Ronald P de Vries
- Molecular Genetics of Industrial Microorganisms, Wageningen University, Dreijenlaan 2, 6703 HA, Wageningen, The Netherlands.
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25
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Abstract
Most aspergilli that produce aflatoxin are members of Aspergillus section Flavi, however isolates of several Aspergillus species not closely related to section Flavi also have been found to produce aflatoxin. Two of the species, Aspergillus ochraceoroseus and an undescribed Aspergillus species SRRC 1468, are morphologically similar to members of Aspergillus section Circumdati. The other species have Emericella teleomorphs (Em. astellata and an undescribed Emericella species SRRC 2520) and are morphologically distinctive in having ascospores with large flanges. All these aflatoxin-producing isolates were from tropical zones near oceans, and none of them grew on artificial media at 37 C. Aflatoxins and sterigmatocystin production were quantified by high-pressure liquid chromatography (HPLC) and confirmed by HPLC-mass spectrometry (LC-MS) detection. Phylogenetic analyses were conducted on these four species using A. parasiticus and Em. nidulans, (which produce aflatoxin and the aflatoxin precursor sterigmatocystin, respectively) for comparison. Two aflatoxin/sterigmatocystin biosynthesis genes and the beta tubulin gene were used in the analyses. Results showed that of the new aflatoxin-producers, Aspergillus SRRC 1468 forms a strongly supported clade with A. ochraceoroseus as does Emericella SRRC 2520 with Em. astellata SRRC 503 and 512.
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Affiliation(s)
- J W Cary
- USDA, ARS, Southern Regional Research Center, 1100 Robert E. Lee Blvd., New Orleans, Louisiana 70124, USA.
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26
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Affiliation(s)
- Rana S Hoda
- Department of Pathology, Medical University of South Carolina, Charleston, South Carolina 29425, USA.
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27
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Koutinas AA, Wang R, Webb C. Restructuring upstream bioprocessing: technological and economical aspects for production of a generic microbial feedstock from wheat. Biotechnol Bioeng 2004; 85:524-38. [PMID: 14760693 DOI: 10.1002/bit.10888] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Restructuring and optimization of the conventional fermentation industry for fuel and chemical production is necessary to replace petrochemical production routes. Guided by this concept, a novel biorefinery process has been developed as an alternative to conventional upstream processing routes, leading to the production of a generic fermentation feedstock from wheat. The robustness of Aspergillus awamori as enzyme producer is exploited in a continuous fungal fermentation on whole wheat flour. Vital gluten is extracted as an added-value byproduct by the conventional Martin process from a fraction of the overall wheat used. Enzymatic hydrolysis of gluten-free flour by the enzyme complex produced by A. awamori during fermentation produces a liquid stream rich in glucose (320 g/L). Autolysis of fungal cells produces a micronutrient-rich solution similar to yeast extract (1.6 g/L nitrogen, 0.5 g/L phosphorus). The case-specific combination of these two liquid streams can provide a nutrient-complete fermentation medium for a spectrum of microbial bioconversions for the production of such chemicals as organic acids, amino acids, bioethanol, glycerol, solvents, and microbial biodegradable plastics. Preliminary economic analysis has shown that the operating cost required to produce the feedstock is dependent on the plant capacity, cereal market price, presence and market value of added-value byproducts, labor costs, and mode of processing (batch or continuous). Integration of this process in an existing fermentation plant could lead to the production of a generic feedstock at an operating cost lower than the market price of glucose syrup (90% to 99% glucose) in the EU, provided that the plant capacity exceeds 410 m(3)/day. Further process improvements are also suggested.
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Affiliation(s)
- A A Koutinas
- Satake Centre for Grain Process Engineering, Department of Chemical Engineering, UMIST, P.O. Box 88, Manchester M60 1QD, United Kingdom.
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28
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Nelson G, Kozlova-Zwinderman O, Collis AJ, Knight MR, Fincham JRS, Stanger CP, Renwick A, Hessing JGM, Punt PJ, van den Hondel CAMJJ, Read ND. Calcium measurement in living filamentous fungi expressing codon-optimized aequorin. Mol Microbiol 2004; 52:1437-50. [PMID: 15165245 DOI: 10.1111/j.1365-2958.2004.04066.x] [Citation(s) in RCA: 85] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Calcium signalling is little understood in filamentous fungi largely because easy and routine methods for calcium measurement in living hyphae have previously been unavailable. We have developed the recombinant aequorin method for this purpose. High levels of aequorin expression were obtained in Neurospora crassa, Aspergillus niger and Aspergillus awamori by codon optimization of the aequorin gene. Three external stimuli (mechanical perturbation, hypo-osmotic shock and high external calcium) were found transiently to increase [Ca(2+)](c). Each of the calcium signatures associated with these physico-chemical treatments was unique, suggesting the involvement of three distinct calcium-mediated signal transduction pathways. The fungal calcium channel blocker KP4 inhibited the [Ca(2+)](c) responses to hypo-osmotic shock and high external calcium, but not to mechanical perturbation. The divalent cation chelator BAPTA inhibited [Ca(2+)](c) responses to mechanical perturbation and hypo-osmotic shock. The calcium agonists A23187 and cyclopiazonic acid increased [Ca(2+)](c) levels.
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Affiliation(s)
- G Nelson
- Fungal Cell Biology Group, Institute of Cell and Molecular Biology, University of Edinburgh, Rutherford Building, Edinburgh EH9 3JH, UK
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29
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Abstract
Members of Aspergillus section Nigri (formerly A. niger group) are distributed worldwide and are regarded as common food spoilage fungi. Some of them are widely used and studied for industrial purposes. They are common sources of extracellular enzymes and organic acids to be used in food processing and are also used in the production of traditional foods, especially in the Orient. Products produced by strains of Aspergillus niger hold the GRAS (Generally Recognised As Safe) status from the FDA. However some species in Aspergillus section Nigri can produce ochratoxin A, a nephrotoxic mycotoxin. In spite of their industrial importance, the taxonomy of black aspergilli ( Aspergillus section Nigri ) is not clear and many attempts have been made in order to find suitable taxonomic criteria. The aim of this paper is to provide an overview of the significance of black aspergilli focusing on all the approaches made in the taxonomy of this group of fungi. Some species, such as A. carbonarius and uniseriate species can be easily recognised. In the A. niger aggregate, although speciation at molecular level has been proposed, no morphological differences can be observed and species identification will therefore remain problematic. Phylogenetic analyses of ITS and 5.8S rDNA gene region of representative black Aspergillus species and a simple key to the most common species that can be easily distinguished by morphological criteria are also included.
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Affiliation(s)
- M Lourdes Abarca
- Departament de Sanitat i d'Anatomia Animals, Facultat de Veterinària, Universitat Autònoma de Barcelona, 08193 Bellaterra, Barcelona, Spain
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30
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Schutyser MAI, de Pagter P, Weber FJ, Briels WJ, Boom RM, Rinzema A. Substrate aggregation due to aerial hyphae during discontinuously mixed solid-state fermentation with Aspergillus oryzae: experiments and modeling. Biotechnol Bioeng 2003; 83:503-13. [PMID: 12827692 DOI: 10.1002/bit.10693] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Solid-state fermentation (SSF) is prone to process failure due to channeling caused by evaporative cooling and the formation of an interparticle mycelium network. Mixing is needed to break the mycelium network and to avoid such failure. This study presents the first attempt to quantify and predict the effect of mycelium bonds on particle mixing and vice versa. We developed a novel experimental set-up to measure the tensile strength of hyphal bonds in SSF: Aspergillus oryzae was cultivated between two wheat-dough disks and the tensile strength of the aerial mycelium was measured with a texture analyzer. Tensile strength at different incubation times was related to oxygen consumption, to allow a translation to a rotating drum with A. oryzae cultivated on wheat grain. We performed several discontinuously mixed solid-state fermentations in the drum fermentor and measured the number and size of grain-aggregates remaining after the first mixing action. We integrated data on mycelium tensile strength into a previously developed two-dimensional discrete-particle model that calculates forces acting on individual substrate particles and the resulting radial-particle movements. The discrete-particle model predicted the quantity and size of the aggregates remaining after mixing successfully. The results show that the first mixing event in SSF with A. oryzae is needed to break mycelium to avoid aggregate formation in the grain bed, and not to distribute water added to compensate for evaporation losses, or smooth out temperature gradients.
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Affiliation(s)
- M A I Schutyser
- Wageningen Centre for Food Sciences, P.O. Box 557, 6700 AN Wageningen, The Netherlands.
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31
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Prathumpai W, Gabelgaard JB, Wanchanthuek P, van de Vondervoort PJI, de Groot MJL, McIntyre M, Nielsen J. Metabolic control analysis of xylose catabolism in Aspergillus. Biotechnol Prog 2003; 19:1136-41. [PMID: 12892473 DOI: 10.1021/bp034020r] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A kinetic model for xylose catabolism in Aspergillus is proposed. From a thermodynamic analysis it was found that the intermediate xylitol will accumulate during xylose catabolism. Use of the kinetic model allowed metabolic control analysis (MCA) of the xylose catabolic pathway to be carried out, and flux control was shown to be dependent on the metabolite levels. Due to thermodynamic constraints, flux control may reside at the first step in the pathway, i.e., at the xylose reductase, even when the intracellular xylitol concentration is high. On the basis of the kinetic analysis, the general dogma specifying that flux control often resides at the step following an intermediate present at high concentrations was, therefore, shown not to hold. The intracellular xylitol concentration was measured in batch cultivations of two different strains of Aspergillus niger and two different strains of Aspergillus nidulans grown on media containing xylose, and a concentration up to 30 mM was found. Applying MCA showed that the first polyol dehydrogenase (XDH) in the catabolic pathway of xylose exerted the main flux control in the two strains of A. nidulans and A. niger NW324, but the flux control was exerted mainly at the first enzyme of the pathway (XR) of A. niger NW 296.
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Affiliation(s)
- W Prathumpai
- Center for Process Biotechnology, BioCentrum-DTU, Technical University of Denmark, DK-2800 Kgs. Lyngby, Denmark
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Roble ND, Ogbonna JC, Tanaka H. A novel circulating loop bioreactor with cells immobilized in loofa ( Luffa cylindrica) sponge for the bioconversion of raw cassava starch to ethanol. Appl Microbiol Biotechnol 2003; 60:671-8. [PMID: 12664145 DOI: 10.1007/s00253-002-1119-0] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2002] [Revised: 07/22/2002] [Accepted: 08/27/2002] [Indexed: 10/25/2022]
Abstract
A circulating loop bioreactor (CLB) with cells immobilized in loofa sponge was constructed for simultaneous aerobic and anaerobic processes. The CLB consists of an aerated riser and a non-aerated downcomer column connected at the top and bottom by cylindrical pipes. Ethanol production from raw cassava starch was investigated in the CLB. Aspergillus awamori IAM 2389 and Saccharomyces cerevisiae IR2 immobilized on loofa sponge were placed, respectively, in the aerated riser column and non-aerated downcomer column. Both alpha-amylase and glucoamylase activities increased as the aeration rate was increased. Ethanol yield and productivity increased with an increase in the aeration rate up to 0.5 vvm, but decreased at higher aeration rates. The CLB was operated at an aeration rate of 0.5 vvm for more than 600 h, resulting in an average ethanol productivity and yield from raw cassava starch of 0.5 g-ethanol l(-1) x h(-1) and 0.45 g ethanol/g starch, respectively. In order to increase ethanol productivity, it was necessary to increase the dissolved oxygen (DO) concentration in the riser column and decrease the DO concentration in the downcomer column. However, increasing the aeration rate resulted in increases in the DO concentration in both the riser and the downcomer columns. At high aeration rate, there was no significant difference in the DO concentration in the riser and downcomer columns. The aeration rate was therefore uncoupled from the liquid circulation by attaching a time-controlled valve in the upper connecting pipe. By optimizing the time and frequency of valve opening, and operation at high aeration rate, it was possible to maintain a very high DO concentration in the riser column and a low DO concentration in the downcomer column. Under these conditions, ethanol productivity increased by more than 100%, to 1.17 g l(-1) x h(-1).
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Affiliation(s)
- N D Roble
- Institute of Applied Biochemistry, University of Tsukuba,1-1-1 Tennodai, Tsukuba, Ibaraki 305, Japan
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Bottone EJ, Peluso RW. Production by Bacillus pumilus (MSH) of an antifungal compound that is active against Mucoraceae and Aspergillus species: preliminary report. J Med Microbiol 2003; 52:69-74. [PMID: 12488568 DOI: 10.1099/jmm.0.04935-0] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
A compound produced by Bacillus pumilus (MSH) that inhibits Mucoraceae and Aspergillus species is described. Fungicidal activity was demonstrated by lawn-spotting and by diffusion through 0.45 microm Millipore membranes placed on 5 % sheep-blood agar, nutrient agar, trypticase soy agar and Mueller-Hinton agar, followed by spore inoculation of the bacterium-free underlying agar surface. With either technique, zones of fungal inhibition correlated with the zone of haemolysis produced by B. pumilus (MSH). The active compound inhibited Mucor and Aspergillus spore germination and aborted elongating hyphae, presumably by inducing a cell-wall lesion. Antifungal activity was stable in agar for a minimum of 8 days, resistant to Pronase degradation, and partially inactivated by chloroform exposure and at pH 5.6. Its molecular mass was determined by diffusion through dialysis membrane to be 500-3000 Da. Attempts at further isolation of the compound have proven unsuccessful to date.
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Affiliation(s)
- Edward J Bottone
- Department of Medicine, Division of Infectious Diseases, The Mount Sinai Hospital and Department of Microbiology, One Gustave L. Levy Place, Mount Sinai School of Medicine, New York, NY 10029, USA
| | - Richard W Peluso
- Department of Medicine, Division of Infectious Diseases, The Mount Sinai Hospital and Department of Microbiology, One Gustave L. Levy Place, Mount Sinai School of Medicine, New York, NY 10029, USA
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Abstract
Fungi generally display either of two growth modes, yeast-like or filamentous, whereas dimorphic fungi, upon environmental stimuli, are able to switch between the yeast-like and the filamentous growth mode. Signal transduction pathways have been elucidated in the budding yeast Saccharomyces cerevisiae, establishing a morphogenetic network that links cell-cycle events with cellular morphogenesis. Recent molecular genetic studies in several filamentous fungal model systems revealed key components required for distinct steps from fungal spore germination to the maintenance of polar hyphal growth, mycelium formation, and nuclear division. This allows a mechanistic comparison of yeast-like and hyphal growth and the establishment of a core model morphogenetic network for filamentous growth including signaling via the cAMP pathway, Rho modules, and cell cycle kinases. Appreciating similarities between morphogenetic networks of the unicellular yeasts and the multicellular filamentous fungi will open new research directions, help in isolating the central network components, and ultimately pave the way to elucidate the central differences (of many) that distinguish, e.g., the growth mode of filamentous fungi from that of their yeast-like relatives, the role of cAMP signaling, and nuclear division.
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Affiliation(s)
- J Wendland
- Department of Microbiology, Friedrich-Schiller University, Jena, D-07745, Germany
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Abstract
Pseudallescheria has been identified as one of the "clinically significant emerging mycoses" but has received little attention in the cytology literature. Recognition of this fungus is of particular importance clinically, because unlike most other fungi (including Aspergillus, with which it is most frequently confused), Pseudallescheria is not effectively treated with amphotericin B, the most frequently and often the only antifungal agent administered. Features helpful in the diagnosis of Pseudallescheria in cytologic material are presented.
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Affiliation(s)
- A E Walts
- Department of Pathology and Laboratory Medicine, Cedars-Sinai Medical Center, Los Angeles, California 90048, USA.
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Abstract
OBJECTIVE Invasive zygomycosis is rapidly progressive and is associated with angioinvasion and infarction. Invasive disease requires emergent surgical and medical intervention. Because it is important for surgical pathologists to recognize these fungi and their preferential sites of growth, the objective of this article is to describe the fungal morphology and histopathologic findings in biopsies from patients with zygomycotic disease, with emphasis on preferential sites of fungal growth. DESIGN Medical record and histologic review identified 20 patients with zygomycosis. Inclusion criteria included the presence of typical ribbonlike hyphae and positive culture, a clinical history of invasive zygomycosis, or both. The histologic features of disease and the fungal morphology were assessed. RESULTS Fungus ball (15%), rhinocerebral (55%), and pulmonary (30%) disease were the types of disease represented. The inflammatory responses were predominantly neutrophilic (50%), predominantly granulomatous (5%), pyogranulomatous (25%), or absent (20%). Invasive disease was characterized by prominent infarcts (94%), angioinvasion (100%), and, surprisingly, prominent perineural invasion (90%) in biopsies that contained nerves for evaluation. At least rare hyphal septa were always seen (100%), and most branches (95%) varied from 45 degrees to 90 degrees. CONCLUSIONS As known to mycologists, zygomycetes are pauciseptate, rather than aseptate, molds. Therefore, the presence of an occasional septum is expected. Perineural invasion is a common finding in invasive zygomycosis, as are angioinvasion and infarcts. Therefore, prior to excluding the presence of these fungi in biopsies suspected to contain zygomycetes, the perineural space should be carefully examined.
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Affiliation(s)
- J L Frater
- Division of Pathology and Laboratory Medicine, Cleveland Clinic Foundation, Ohio 44195, USA
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38
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Abstract
The filamentous fungi Aspergillus oryzae and A. niger grow by apical extension of multinucleate hyphae that are subdivided into compartments by cross-walls called septa. Submerged cultivation, image analysis, and fluorescence microscopy were used to study the role of the carbon source on mitosis and hyphal extension in these fungi. In the two species of Aspergillus, the length of the apical compartment, the number of nuclei in the apical compartment, and the hyphal diameter were regulated in response to the surrounding glucose concentration. A long apical compartment with many nuclei was the result of a high glucose concentration, whereas a short apical compartment with few nuclei was the result of a low glucose concentration. This is the first study of the influence of glucose concentration on nuclear mitosis and septation in filamentous fungi grown submerged. In addition, this is the first time a model of the duplication cycle in higher filamentous fungi has been simulated.
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Affiliation(s)
- C Müller
- Center for Process Biotechnology, Department of Biotechnology, Building 223, Technical University of Denmark, 2800 Lyngby, Denmark
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39
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Abstract
The intact fungal spores of several strains of four Aspergillus species, Aspergillus flavus, A. oryzae, A. parasiticus, and A. sojae, were directly analyzed by matrix-assisted laser desorption/ionization (MALDI) time-of-flight mass spectrometry. Very simple MALDI mass spectra are obtained by directly mixing spores with a matrix such as alpha-cyano-4-hydroxycinnamic acid or sinapinic acid. The mass spectra are obtained from the ablation of cell walls of spores owing to the acidity of the matrix solution. The MALDI results show that aflatoxigenic strains and non-aflatoxigenic strains have different mass peak profiles. Furthermore, the MALDI results of non-aflatoxigenic A. flavus and A. parasiticus spores resemble those of the closely related A. oryzae and A. sojae spores, respectively.
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Affiliation(s)
- T Y Li
- Institute of Toxicology, Tzu Chi University, Hualien 970, Taiwan
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40
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Harris SD, Hofmann AF, Tedford HW, Lee MP. Identification and characterization of genes required for hyphal morphogenesis in the filamentous fungus Aspergillus nidulans. Genetics 1999; 151:1015-25. [PMID: 10049919 PMCID: PMC1460524 DOI: 10.1093/genetics/151.3.1015] [Citation(s) in RCA: 70] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
In the filamentous fungus Aspergillus nidulans, germination of an asexual conidiospore results in the formation of a hyphal cell. A key feature of spore germination is the switch from isotropic spore expansion to polarized apical growth. Here, temperature-sensitive mutations are used to characterize the roles of five genes (sepA, hypA, podB-podD) in the establishment and maintenance of hyphal polarity. Evidence that suggests that the hypA, podB, and sepA genes are required for multiple aspects of hyphal morphogenesis is presented. Notably, podB and sepA are needed for organization of the cytoskeleton at sites of polarized growth. In contrast, podC and podD encode proteins that appear to be specifically required for the establishment of hyphal polarity during spore germination. The role of sepA and the pod genes in controlling the spatial pattern of polarized morphogenesis in germinating spores is also described. Results obtained from these experiments indicate that the normal pattern of germ-tube emergence is dependent upon the integrity of the actin cytoskeleton.
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Affiliation(s)
- S D Harris
- Department of Microbiology, University of Connecticut Health Center, Farmington, Connecticut 06030-3205, USA.
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41
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Horiuchi H, Takagi M. [The roles of chitin synthases and chitinases on the tip growth and the differentiation of filamentous fungi]. Tanpakushitsu Kakusan Koso 1998; 43:2182-90. [PMID: 9868354] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Affiliation(s)
- H Horiuchi
- Department of Biotechnology, University of Tokyo, Japan
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42
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Abstract
Generalizing results from fungal fermentations is difficult due to their high sensitivity toward slight variation in starting conditions, poor reproducibility, and difference in strains. In this study a mathematical model is presented in which oxygen transfer, agitation intensity, dissolved oxygen tension, pellet size, formation of mycelia, the fraction of mycelia in the total biomass, carbohydrate source consumption, and biomass growth are taken into account. Two parameters were estimated from simulation, whereas all others are based on measurements or were taken from literature. Experimental data are obtained from the fermentations in both 2 L and 100 L fermentors at various conditions. Comparison of the simulation with experiments shows that the model can fairly well describe the time course of fungal growth (such as biomass and carbohydrate source concentrations) and fungal morphology (such as pellet size and the fraction of pellets in the total biomass). The model predicts that a stronger agitation intensity leads to a smaller pellet size and a lower fraction of pellets in the total biomass. At the same agitation intensity, pellet size is hardly affected by the dissolved oxygen tension, whereas the fraction of mycelia decreases slightly with an increase of the dissolved oxygen tension in the bulk. All of these are in line with observations at the corresponding conditions.
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Affiliation(s)
- Y Q Cui
- Department of Biochemical Engineering, Delft University of Technology, Julianalaan 67, 2628 BC Delft, The Netherlands.
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43
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Abstract
Butyrolactone I [alpha-oxo-beta-(p-hydroxyphenyl)-gamma-(p-hydroxy-m-3, 3-dimethylallyl-benzyl)-gamma-methoxycarbonyl-gamma-butyrolactone] is produced as a secondary metabolite by Aspergillus terreus. Because small butyrolactone-containing molecules act as self-regulating factors in some bacteria, the effects of butyrolactone I on the producing organism were studied; specifically, changes in morphology, sporulation, and secondary metabolism were studied. Threefold or greater increases in hyphal branching (with concomitant decreases in the average hyphal growth unit), submerged sporulation, and secondary metabolism were observed when butyrolactone I was added to cultures of A. terreus. Among the secondary metabolites whose production was increased by this treatment was the therapeutically important compound lovastatin. These findings indicate that butyrolactone I induces morphological and sporulation changes in A. terreus and enhances secondary metabolite production in a manner similar to that previously reported for filamentous bacteria.
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Affiliation(s)
- T G Schimmel
- Technical Operations, Merck and Co., Inc., Elkton, Virginia 22827, USA.
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44
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Cui YQ, van der Lans RG, Luyben KC. Effects of dissolved oxygen tension and mechanical forces on fungal morphology in submerged fermentation. Biotechnol Bioeng 1998; 57:409-19. [PMID: 10099217] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
Abstract
The effects of dissolved oxygen tension and mechanical forces on fungal morphology were both studied in the submerged fermentation of Aspergillus awamori. Pellet size, the hairy length of pellets, and the free filamentous mycelial fraction in the total biomass were found to be a function of the mechanical force intensity and to be independent of the dissolved oxygen tension provided that the dissolved oxygen tension was neither too low (5%) nor too high (330%). When the dissolved oxygen concentration was close to the saturation concentration corresponding to pure oxygen gas, A. awamori formed denser pellets and the free filamentous mycelial fraction was almost zero for a power input of about 1 W/kg. In the case of very low dissolved oxygen tension, the pellets were rather weak and fluffy so that they showed a very different appearance. The amount of biomass per pellet surface area appeared to be affected only by the dissolved oxygen tension and was proportional to the average dissolved oxygen tension to the power of 0.33. From this it was concluded that molecular diffusion was the dominant mechanism for oxygen transfer in the pellets and that convection and turbulent flow in the pellets were negligible in submerged fermentations. The biomass per wet pellet volume increased with the dissolved oxygen tension and decreased with the size of the pellets. This means that the smaller pellets formed under a higher dissolved oxygen tension had a higher intrinsic strength. Correspondingly, the porosity of the pellets was a function of the dissolved oxygen tension and the size of pellets. Within the studied range, the void fraction in the pellets was high and always much more than 50%.
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Affiliation(s)
- Y Q Cui
- Department of Biochemical Engineering, Delft University of Technology, Julianalaan 67, 2628 BC Delft, The Netherlands.
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46
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Abstract
The initiation of anaphase and exit from mitosis require the activation of a proteolytic system that ubiquitinates and degrades cyclin B. The regulated component of this system is a large ubiquitin ligase complex, termed the anaphase-promoting complex (APC) or cyclosome. Purified Xenopus laevis APC was found to be composed of eight major subunits, at least four of which became phosphorylated in mitosis. In addition to CDC27, CDC16, and CDC23, APC contained a homolog of Aspergillus nidulans BIME, a protein essential for anaphase. Because mutation of bimE can bypass the interphase arrest induced by either nimA mutation or unreplicated DNA, it appears that ubiquitination catalyzed by APC may also negatively regulate entry into mitosis.
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Affiliation(s)
- J M Peters
- Department of Cell Biology, Harvard Medical School, 240 Longwood Avenue, Boston, MA 02115, USA
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Abstract
Mycotoxigenic fungi were isolated and identified from selected food and feed samples obtained in Metro Manila public markets, a Laguna coconut mill, and FNRI rat breeder's diet using the serial dilution and moisture chamber techniques. The majority of the isolates identified belong to the genera Aspergillus and Mucorales and a few to the Penicillium. Taxonomical identification was based on the morphological characteristics of the fungi as observed under the microscope.
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Affiliation(s)
- A F Lozada
- Food and Nutrition Research Institute (FNRI), Department of Science and Technology (DOST), Bicutan, Taguig, Metro Manila, Philippines
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Garcia-Gonzalez M, Sanroman AL, Arribas R, Torres G, Cuesta C, Moreira VF. Invasive pulmonary aspergillosis: a rare presentation of non-Hodgkin's lymphoma. Postgrad Med J 1994; 70:459-60. [PMID: 8029172 PMCID: PMC2397714 DOI: 10.1136/pgmj.70.824.459] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
We describe a patient with rapidly progressive pneumonia and a high level of serum lactate dehydrogenase, in whom postmortem study revealed the presence of a diffuse, small and large-cell multicentric non-Hodgkin's lymphoma, together with an invasive pulmonary aspergillosis. Aspergillosis is rare as a presenting feature of a lymphoproliferative disease; only one previous case has been reported to the best of our knowledge. Invasive aspergillosis and lymphoma should be considered in patients presenting with pneumonia and high level of lactate dehydrogenase.
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Henwick S, Hetherington SV, Patrick CC. Complement binding to Aspergillus conidia correlates with pathogenicity. J Lab Clin Med 1993; 122:27-35. [PMID: 8320488] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Complement has significant effects on the phagocytosis of Aspergillus organisms. We examined the amount and type of complement component C3 bound to the resting conidia of 29 isolates from nine Aspergillus species. The highly pathogenic species A. fumigatus and A. flavus bound fewer C3 molecules per unit of conidial surface area than did the less pathogenic species A. glaucus, A. nidulans, A. niger, A. ochraceus, A. terreus, A. versicolor, and A. wentii, as determined by quantitative flow cytometry. Immunoblot analysis of C3 fragments bound to conidia demonstrated that for all species most C3b was apparently converted to iC3b. For seven species, iC3b was clearly the major C3 product recognized by immunoblotting. However, A. niger and A. nidulans appear to promote further breakdown of opsonic C3 fragments to C3dg. We found significant variations in size and C3 binding among isolates within the same species. Intraspecies variation may contribute to seemingly discrepant results obtained in studies of Aspergillus phagocytosis.
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Affiliation(s)
- S Henwick
- Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, TN 38101-0318
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50
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Abstract
The production and secretion of restrictocin (a cytotoxin that cleaves ribosomal RNA) by cultures of the fungus Aspergillus restrictus was investigated. Previous studies have indicated that restrictocin production in liquid culture coincides with the appearance of differentiated cell structures. A study of the correlation between the appearance of differentiated structures and restrictocin production was conducted with A. restrictus grown on agar medium. Restrictocin was found to be associated with the cell mass of the agar-grown culture (in contrast to liquid cultures), and was first observed when aerial hyphae emerged. Restrictocin levels increased until the time of conidiation, after which they fell off sharply. No restrictocin could be found in the agar medium. The presence of restrictocin upon and within various cell structures was determined by immunofluorescent laser microscopy. This study showed that restrictocin became localized to the conidiophores and phialides during the process of conidiation. Prior to this, restrictocin was found within the hyphae in localized concentrations that may correspond to secretory vesicles.
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Affiliation(s)
- T T Brandhorst
- Department of Biochemistry, College of Agricultural and Life Sciences, University of Wisconsin, Madison 53706
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