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Numazawa R, Tanaka Y, Nishioka S, Tsuji R, Maeda H, Tanaka M, Takeuchi M, Yamagata Y. Aspergillus oryzae PrtR alters transcription of individual peptidase genes in response to the growth environment. Appl Microbiol Biotechnol 2024; 108:90. [PMID: 38204127 PMCID: PMC10781853 DOI: 10.1007/s00253-023-12833-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Revised: 09/19/2023] [Accepted: 09/30/2023] [Indexed: 01/12/2024]
Abstract
Aspergillus oryzae PrtR is an ortholog of the transcription factor PrtT, which positively regulates the transcription of extracellular peptidase genes in Aspergillus niger and Aspergillus fumigatus. To identify the genes under the control of PrtR and elucidate its regulatory mechanism in A. oryzae, prtR gene disruption mutants were generated. The control strain clearly showed a halo on media containing skim milk as the nitrogen source, whereas the ΔprtR strain formed a smaller halo. Measurement of acid peptidase activity revealed that approximately 84% of acidic endopeptidase and 86% of carboxypeptidase activities are positively regulated by PrtR. As the transcription of the prtR gene varied depending on culture conditions, especially with or without a protein substrate, it was considered that its transcription would be regulated in response to a nitrogen source. In addition, contrary to previous expectations, PrtR was found to act both in promoting and repressing the transcription of extracellular peptidase genes. The mode of regulation varied from gene to gene. Some genes were regulated in the same manner in both liquid and solid cultures, whereas others were regulated in different ways depending on the culture conditions. Furthermore, PrtR has been suggested to regulate the transcription of peptidase genes that are closely associated with other transcription factors. KEY POINTS: • Almost all peptidase genes in Aspergillus oryzae are positively regulated by PrtR • However, several genes are regulated negatively by PrtR • PrtR optimizes transcription of peptidase genes in response to culture conditions.
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Affiliation(s)
- Rika Numazawa
- Department of Applied Biological Science, United Graduate School of Agricultural Science, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai-Cho, Fuchu, Tokyo, 1838509, Japan
| | - Yukako Tanaka
- Department of Applied Biological Chemistry, Graduate School of Agriculture, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai-Cho, Fuchu, Tokyo, 1838509, Japan
| | - Sawako Nishioka
- Department of Applied Biological Chemistry, Graduate School of Agriculture, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai-Cho, Fuchu, Tokyo, 1838509, Japan
| | - Ryotaro Tsuji
- Department of Applied Biological Chemistry, Graduate School of Agriculture, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai-Cho, Fuchu, Tokyo, 1838509, Japan
| | - Hiroshi Maeda
- Department of Applied Biological Chemistry, Graduate School of Agriculture, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai-Cho, Fuchu, Tokyo, 1838509, Japan
| | - Mizuki Tanaka
- Department of Applied Biological Science, United Graduate School of Agricultural Science, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai-Cho, Fuchu, Tokyo, 1838509, Japan
- Department of Applied Biological Chemistry, Graduate School of Agriculture, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai-Cho, Fuchu, Tokyo, 1838509, Japan
| | - Michio Takeuchi
- Department of Applied Biological Science, United Graduate School of Agricultural Science, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai-Cho, Fuchu, Tokyo, 1838509, Japan
- Department of Applied Biological Chemistry, Graduate School of Agriculture, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai-Cho, Fuchu, Tokyo, 1838509, Japan
| | - Youhei Yamagata
- Department of Applied Biological Science, United Graduate School of Agricultural Science, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai-Cho, Fuchu, Tokyo, 1838509, Japan.
- Department of Applied Biological Chemistry, Graduate School of Agriculture, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai-Cho, Fuchu, Tokyo, 1838509, Japan.
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Liu D, Garrigues S, Culleton H, McKie VA, de Vries RP. Analysis of the molecular basis for the non-amylolytic and non-proteolytic nature of Aspergillus vadensis CBS 113365. N Biotechnol 2024; 82:25-32. [PMID: 38697469 DOI: 10.1016/j.nbt.2024.04.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2023] [Revised: 04/01/2024] [Accepted: 04/29/2024] [Indexed: 05/05/2024]
Abstract
Aspergillus vadensis CBS 113365, a close relative of A. niger, has been suggested as a more favourable alternative for recombinant protein production as it does not acidify the culture medium and produces very low levels of extracellular proteases. The aim of this study was to investigate the underlying cause of the non-amylolytic and non-proteolytic phenotype of A. vadensis CBS 113365. Our results demonstrate that the non-functionality of the amylolytic transcription factor AmyR in A. vadensis CBS 113365 is primarily attributed to the lack of functionality of its gene's promoter sequence. In contrast, a different mechanism is likely causing the lack of PrtT activity, which is the main transcriptional regulator of protease production. The findings presented here not only expand our understanding of the genetic basis behind the distinct characteristics of A. vadensis CBS 113365, but also underscore its potential as a favourable alternative for recombinant protein production.
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Affiliation(s)
- Dujuan Liu
- Fungal Physiology, Westerdijk Fungal Biodiversity Institute & Fungal Molecular Physiology, Utrecht University, Uppsalalaan 8, 3584 CT Utrecht, the Netherlands
| | - Sandra Garrigues
- Fungal Physiology, Westerdijk Fungal Biodiversity Institute & Fungal Molecular Physiology, Utrecht University, Uppsalalaan 8, 3584 CT Utrecht, the Netherlands; Departament of Food Biotechnology, Instituto de Agroquímica y Tecnología de Alimentos (IATA), Consejo Superior de Investigaciones Científicas (CSIC), Paterna, Valencia, Spain
| | - Helena Culleton
- Fungal Physiology, Westerdijk Fungal Biodiversity Institute & Fungal Molecular Physiology, Utrecht University, Uppsalalaan 8, 3584 CT Utrecht, the Netherlands; Megazyme International Ireland, Bray, Co. Wicklow, Ireland
| | | | - Ronald P de Vries
- Fungal Physiology, Westerdijk Fungal Biodiversity Institute & Fungal Molecular Physiology, Utrecht University, Uppsalalaan 8, 3584 CT Utrecht, the Netherlands.
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Wang C, Zhang X, Wu K, Liu S, Li X, Zhu C, Xiao Y, Fang Z, Liu J. Two Zn 2Cys 6-type transcription factors respond to aromatic compounds and regulate the expression of laccases in the white-rot fungus Trametes hirsuta. Appl Environ Microbiol 2024:e0054524. [PMID: 38899887 DOI: 10.1128/aem.00545-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2024] [Accepted: 05/29/2024] [Indexed: 06/21/2024] Open
Abstract
White-rot fungi differentially express laccases when they encounter aromatic compounds. However, the underlying mechanisms are still being explored. Here, proteomics analysis revealed that in addition to increased laccase activity, proteins involved in sphingolipid metabolism and toluene degradation as well as some cytochrome P450s (CYP450s) were differentially expressed and significantly enriched during 48 h of o-toluidine exposure, in Trametes hirsuta AH28-2. Two Zn2Cys6-type transcription factors (TFs), TH8421 and TH4300, were upregulated. Bioinformatics docking and isothermal titration calorimetry assays showed that each of them could bind directly to o-toluidine and another aromatic monomer, guaiacol. Binding to aromatic compounds promoted the formation of TH8421/TH4300 heterodimers. TH8421 and TH4300 silencing in T. hirsuta AH28-2 led to decreased transcriptional levels and activities of LacA and LacB upon o-toluidine and guaiacol exposure. EMSA and ChIP-qPCR analysis further showed that TH8421 and TH4300 bound directly with the promoter regions of lacA and lacB containing CGG or CCG motifs. Furthermore, the two TFs were involved in direct and positive regulation of the transcription of some CYP450s. Together, TH8421 and TH4300, two key regulators found in T. hirsuta AH28-2, function as heterodimers to simultaneously trigger the expression of downstream laccases and intracellular enzymes. Monomeric aromatic compounds act as ligands to promote heterodimer formation and enhance the transcriptional activities of the two TFs.IMPORTANCEWhite-rot fungi differentially express laccase isoenzymes when exposed to aromatic compounds. Clarification of the molecular mechanisms underlying differential laccase expression is essential to elucidate how white-rot fungi respond to the environment. Our study shows that two Zn2Cys6-type transcription factors form heterodimers, interact with the promoters of laccase genes, and positively regulate laccase transcription in Trametes hirsuta AH28-2. Aromatic monomer addition induces faster heterodimer formation and rate of activity. These findings not only identify two new transcription factors involved in fungal laccase transcription but also deepen our understanding of the mechanisms underlying the response to aromatics exposure in white-rot fungi.
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Affiliation(s)
- Chenkai Wang
- School of Life Sciences, Anhui University, Hefei, Anhui, China
- Anhui Key Laboratory of Modern Biomanufacturing, Hefei, Anhui, China
- Anhui Provincial Engineering Technology Research Center of Microorganisms and Biocatalysis, Hefei, Anhui, China
| | - Xinlei Zhang
- School of Life Sciences, Anhui University, Hefei, Anhui, China
- Anhui Key Laboratory of Modern Biomanufacturing, Hefei, Anhui, China
- Anhui Provincial Engineering Technology Research Center of Microorganisms and Biocatalysis, Hefei, Anhui, China
| | - Kun Wu
- School of Life Sciences, Anhui University, Hefei, Anhui, China
- Anhui Key Laboratory of Modern Biomanufacturing, Hefei, Anhui, China
- Anhui Provincial Engineering Technology Research Center of Microorganisms and Biocatalysis, Hefei, Anhui, China
| | - Shenglong Liu
- School of Life Sciences, Anhui University, Hefei, Anhui, China
- Anhui Key Laboratory of Modern Biomanufacturing, Hefei, Anhui, China
- Anhui Provincial Engineering Technology Research Center of Microorganisms and Biocatalysis, Hefei, Anhui, China
| | - Xiang Li
- School of Life Sciences, Anhui University, Hefei, Anhui, China
| | - Chaona Zhu
- School of Life Sciences, Anhui University, Hefei, Anhui, China
| | - Yazhong Xiao
- School of Life Sciences, Anhui University, Hefei, Anhui, China
- Anhui Key Laboratory of Modern Biomanufacturing, Hefei, Anhui, China
- Anhui Provincial Engineering Technology Research Center of Microorganisms and Biocatalysis, Hefei, Anhui, China
| | - Zemin Fang
- School of Life Sciences, Anhui University, Hefei, Anhui, China
- Anhui Key Laboratory of Modern Biomanufacturing, Hefei, Anhui, China
- Anhui Provincial Engineering Technology Research Center of Microorganisms and Biocatalysis, Hefei, Anhui, China
| | - Juanjuan Liu
- School of Life Sciences, Anhui University, Hefei, Anhui, China
- Anhui Key Laboratory of Modern Biomanufacturing, Hefei, Anhui, China
- Anhui Provincial Engineering Technology Research Center of Microorganisms and Biocatalysis, Hefei, Anhui, China
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Chen X, Moran Torres JP, Jan Vonk P, Damen JMA, Reiding KR, Dijksterhuis J, Lugones LG, Wösten HAB. The pleiotropic phenotype of FlbA of Aspergillus niger is explained in part by the activity of seven of its downstream-regulated transcription factors. Fungal Genet Biol 2024; 172:103894. [PMID: 38657897 DOI: 10.1016/j.fgb.2024.103894] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2024] [Revised: 04/03/2024] [Accepted: 04/22/2024] [Indexed: 04/26/2024]
Abstract
Inactivation of flbA in Aspergillus niger results in thinner cell walls, increased cell lysis, abolished sporulation, and an increased secretome complexity. A total of 36 transcription factor (TF) genes are differentially expressed in ΔflbA. Here, seven of these genes (abaA, aslA, aslB, azf1, htfA, nosA, and srbA) were inactivated. Inactivation of each of these genes affected sporulation and, with the exception of abaA, cell wall integrity and protein secretion. The impact on secretion was strongest in the case of ΔaslA and ΔaslB that showed increased pepsin, cellulase, and amylase activity. Biomass was reduced of agar cultures of ΔabaA, ΔaslA, ΔnosA, and ΔsrbA, while biomass was higher in liquid shaken cultures of ΔaslA and ΔaslB. The ΔaslA and ΔhtfA strains showed increased resistance to H2O2, while ΔaslB was more sensitive to this reactive oxygen species. Together, inactivation of the seven TF genes impacted biomass formation, sporulation, protein secretion, and stress resistance, and thereby these genes explain at least part of the pleiotropic phenotype of ΔflbA of A. niger.
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Affiliation(s)
- Xiaoyi Chen
- Microbiology, Department of Biology, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands.
| | - Juan P Moran Torres
- Microbiology, Department of Biology, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands.
| | - Peter Jan Vonk
- Microbiology, Department of Biology, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands.
| | - J Mirjam A Damen
- Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands.
| | - Karli R Reiding
- Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands.
| | - Jan Dijksterhuis
- Westerdijk Fungal Biodiversity Institute, Uppsalalaan 8, 3584 CT Utrecht, The Netherlands.
| | - Luis G Lugones
- Microbiology, Department of Biology, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands.
| | - Han A B Wösten
- Microbiology, Department of Biology, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands.
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Arentshorst M, Kooloth Valappil P, Mózsik L, Regensburg-Tuïnk TJG, Seekles SJ, Tjallinks G, Fraaije MW, Visser J, Ram AFJ. A CRISPR/Cas9-based multicopy integration system for protein production in Aspergillus niger. FEBS J 2023; 290:5127-5140. [PMID: 37335926 DOI: 10.1111/febs.16891] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Revised: 04/25/2023] [Accepted: 06/16/2023] [Indexed: 06/21/2023]
Abstract
The filamentous fungus Aspergillus niger is well known for its high protein secretion capacity and a preferred host for homologous and heterologous protein production. To improve the protein production capacity of A. niger even further, a set of dedicated protein production strains was made containing up to 10 glucoamylase landing sites (GLSs) at predetermined sites in the genome. These GLSs replace genes encoding enzymes abundantly present or encoding unwanted functions. Each GLS contains the promotor and terminator region of the glucoamylase gene (glaA), one of the highest expressed genes in A. niger. Integrating multiple gene copies, often realized by random integration, is known to boost protein production yields. In our approach the GLSs allow for rapid targeted gene replacement using CRISPR/Cas9-mediated genome editing. By introducing the same or different unique DNA sequences (dubbed KORE sequences) in each GLS and designing Cas9-compatible single guide RNAs, one is able to select at which GLS integration of a target gene occurs. In this way a set of identical strains with different copy numbers of the gene of interest can be easily and rapidly made to compare protein production levels. As an illustration of its potential, we successfully used the expression platform to generate multicopy A. niger strains producing the Penicillium expansum PatE::6xHis protein catalysing the final step in patulin biosynthesis. The A. niger strain expressing 10 copies of the patE::6xHis expression cassette produced about 70 μg·mL-1 PatE protein in the culture medium with a purity just under 90%.
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Affiliation(s)
- Mark Arentshorst
- Microbial Sciences, Fungal Genetics and Biotechnology, Institute of Biology Leiden, Leiden University, The Netherlands
| | - Prajeesh Kooloth Valappil
- Microbial Sciences, Fungal Genetics and Biotechnology, Institute of Biology Leiden, Leiden University, The Netherlands
| | - László Mózsik
- Microbial Sciences, Fungal Genetics and Biotechnology, Institute of Biology Leiden, Leiden University, The Netherlands
| | - Tonny J G Regensburg-Tuïnk
- Microbial Sciences, Fungal Genetics and Biotechnology, Institute of Biology Leiden, Leiden University, The Netherlands
| | - Sjoerd J Seekles
- Microbial Sciences, Fungal Genetics and Biotechnology, Institute of Biology Leiden, Leiden University, The Netherlands
| | - Gwen Tjallinks
- Molecular Enzymology, University of Groningen, The Netherlands
| | - Marco W Fraaije
- Molecular Enzymology, University of Groningen, The Netherlands
| | - Jaap Visser
- Microbial Sciences, Fungal Genetics and Biotechnology, Institute of Biology Leiden, Leiden University, The Netherlands
| | - Arthur F J Ram
- Microbial Sciences, Fungal Genetics and Biotechnology, Institute of Biology Leiden, Leiden University, The Netherlands
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Yan Q, Han L, Liu Z, Zhou S, Zhou Z. Stepwise genetic modification for efficient expression of heterologous proteins in Aspergillus nidulans. Appl Microbiol Biotechnol 2023; 107:6923-6935. [PMID: 37698610 DOI: 10.1007/s00253-023-12755-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2023] [Revised: 08/09/2023] [Accepted: 08/26/2023] [Indexed: 09/13/2023]
Abstract
Filamentous fungi are widely used in food fermentation and therapeutic protein production due to their prominent protein secretion and post-translational modification system. Aspergillus nidulans is an important model strain of filamentous fungi, but not a fully developed cell factory for heterologous protein expression. One of the limitations is its relatively low capacity of protein secretion. To alleviate this limitation, in this study, the protein secretory pathway and mycelium morphology were stepwise modified. With eGFP as a reporter protein, protein secretion was significantly enhanced through reducing the degradation of heterologous proteins by endoplasmic reticulum-associated protein degradation (ERAD) and vacuoles in the secretory pathway. Elimination of mycelial aggregation resulted in a 1.5-fold and 1.3-fold increase in secretory expression of eGFP in typical constitutive and inducible expression systems, respectively. Combined with these modifications, high secretory expression of human interleukin-6 (HuIL-6) was achieved. Consequently, a higher yield of secretory HuIL-6 was realized by further disruption of extracellular proteases. Overall, a superior chassis cell of A. nidulans suitable for efficient secretory expression of heterologous proteins was successfully obtained, providing a promising platform for biosynthesis using filamentous fungi as hosts. KEY POINTS: • Elimination of mycelial aggregation and decreasing the degradation of heterologous protein are effective strategies for improving the heterologous protein expression. • The work provides a high-performance chassis host △agsB-derA for heterologous protein secretory expression. • Human interleukin-6 (HuIL-6) was expressed efficiently in the high-performance chassis host △agsB-derA.
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Affiliation(s)
- Qin Yan
- School of Biotechnology, Jiangnan University, Wuxi, Jiangsu, China
| | - Laichuang Han
- School of Biotechnology, Jiangnan University, Wuxi, Jiangsu, China
| | - Zhongmei Liu
- School of Biotechnology, Jiangnan University, Wuxi, Jiangsu, China
- Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, Wuxi, Jiangsu, 214122, China
| | - Shengmin Zhou
- State Key Laboratory of Bioreactor Engineering, School of Biotechnology, East China University of Science and Technology, Shanghai, China.
| | - Zhemin Zhou
- School of Biotechnology, Jiangnan University, Wuxi, Jiangsu, China.
- Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, Wuxi, Jiangsu, 214122, China.
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Kerkaert JD, Huberman LB. Regulation of nutrient utilization in filamentous fungi. Appl Microbiol Biotechnol 2023; 107:5873-5898. [PMID: 37540250 PMCID: PMC10983054 DOI: 10.1007/s00253-023-12680-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Revised: 06/29/2023] [Accepted: 07/04/2023] [Indexed: 08/05/2023]
Abstract
Organisms must accurately sense and respond to nutrients to survive. In filamentous fungi, accurate nutrient sensing is important in the establishment of fungal colonies and in continued, rapid growth for the exploitation of environmental resources. To ensure efficient nutrient utilization, fungi have evolved a combination of activating and repressing genetic networks to tightly regulate metabolic pathways and distinguish between preferred nutrients, which require minimal energy and resources to utilize, and nonpreferred nutrients, which have more energy-intensive catabolic requirements. Genes necessary for the utilization of nonpreferred carbon sources are activated by transcription factors that respond to the presence of the specific nutrient and repressed by transcription factors that respond to the presence of preferred carbohydrates. Utilization of nonpreferred nitrogen sources generally requires two transcription factors. Pathway-specific transcription factors respond to the presence of a specific nonpreferred nitrogen source, while another transcription factor activates genes in the absence of preferred nitrogen sources. In this review, we discuss the roles of transcription factors and upstream regulatory genes that respond to preferred and nonpreferred carbon and nitrogen sources and their roles in regulating carbon and nitrogen catabolism. KEY POINTS: • Interplay of activating and repressing transcriptional networks regulates catabolism. • Nutrient-specific activating transcriptional pathways provide metabolic specificity. • Repressing regulatory systems differentiate nutrients in mixed nutrient environments.
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Affiliation(s)
- Joshua D Kerkaert
- Plant Pathology and Plant-Microbe Biology Section, School of Integrative Plant Science, Cornell University, Ithaca, NY, USA
| | - Lori B Huberman
- Plant Pathology and Plant-Microbe Biology Section, School of Integrative Plant Science, Cornell University, Ithaca, NY, USA.
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Igarashi T, Katayama T, Maruyama JI. CRISPR/Cas9 genome editing for comparative genetic analysis related to soy sauce brewing in Aspergillus sojae industrial strains. Biosci Biotechnol Biochem 2023; 87:1236-1248. [PMID: 37500264 DOI: 10.1093/bbb/zbad101] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Accepted: 07/11/2023] [Indexed: 07/29/2023]
Abstract
Aspergillus sojae has traditionally been used in soy sauce brewing. Genetic modification techniques have been established in A. sojae, but it is difficult to apply them to various industrial strains. Although we have previously developed a CRISPR/Cpf1 system for genetic modification of A. sojae, another genome editing system was required for versatile modification. In addition, repetitive genetic modification using the CRISPR system has not been established in A. sojae. In this study, we demonstrated mutagenesis, gene deletion/integration, and large deletion of a chromosomal region in A. sojae using the CRISPR/Cas9 system. We also successfully performed repetitive genetic modification using a method that involved forced recycling of genome-editing plasmids. Moreover, we demonstrated that the effects of genetic modification related to soy sauce brewing differed among A. sojae industrial strains. These results showed that our technique of using the CRISPR/Cas9 system is a powerful tool for genetic modification in A. sojae.
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Affiliation(s)
- Takayuki Igarashi
- Department of Biotechnology, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
| | - Takuya Katayama
- Department of Biotechnology, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
- Collaborative Research Institute for Innovative Microbiology, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
| | - Jun-Ichi Maruyama
- Department of Biotechnology, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
- Collaborative Research Institute for Innovative Microbiology, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
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Mathieu Y, Raji O, Bellemare A, Di Falco M, Nguyen TTM, Viborg AH, Tsang A, Master E, Brumer H. Functional characterization of fungal lytic polysaccharide monooxygenases for cellulose surface oxidation. BIOTECHNOLOGY FOR BIOFUELS AND BIOPRODUCTS 2023; 16:132. [PMID: 37679837 PMCID: PMC10486138 DOI: 10.1186/s13068-023-02383-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2023] [Accepted: 08/14/2023] [Indexed: 09/09/2023]
Abstract
BACKGROUND Microbial lytic polysaccharide monooxygenases (LPMOs) cleave diverse biomass polysaccharides, including cellulose and hemicelluloses, by initial oxidation at C1 or C4 of glycan chains. Within the Carbohydrate-Active Enzymes (CAZy) classification, Auxiliary Activity Family 9 (AA9) comprises the first and largest group of fungal LPMOs, which are often also found in tandem with non-catalytic carbohydrate-binding modules (CBMs). LPMOs originally attracted attention for their ability to potentiate complete biomass deconstruction to monosaccharides. More recently, LPMOs have been applied for selective surface modification of insoluble cellulose and chitin. RESULTS To further explore the catalytic diversity of AA9 LPMOs, over 17,000 sequences were extracted from public databases, filtered, and used to construct a sequence similarity network (SSN) comprising 33 phylogenetically supported clusters. From these, 32 targets were produced successfully in the industrial filamentous fungus Aspergillus niger, 25 of which produced detectable LPMO activity. Detailed biochemical characterization of the eight most highly produced targets revealed individual C1, C4, and mixed C1/C4 regiospecificities of cellulose surface oxidation, different redox co-substrate preferences, and CBM targeting effects. Specifically, the presence of a CBM correlated with increased formation of soluble oxidized products and a more localized pattern of surface oxidation, as indicated by carbonyl-specific fluorescent labeling. On the other hand, LPMOs without native CBMs were associated with minimal release of soluble products and comparatively dispersed oxidation pattern. CONCLUSIONS This work provides insight into the structural and functional diversity of LPMOs, and highlights the need for further detailed characterization of individual enzymes to identify those best suited for cellulose saccharification versus surface functionalization toward biomaterials applications.
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Affiliation(s)
- Yann Mathieu
- Michael Smith Laboratories, University of British Columbia, 2185 East Mall, Vancouver, BC, V6T 1Z4, Canada
- BioProducts Institute, University of British Columbia, 2385 East Mall, Vancouver, BC, V6T 1Z4, Canada
| | - Olanrewaju Raji
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, ON, M5S 3E5, Canada
| | - Annie Bellemare
- Centre for Structural & Functional Genomics, Concordia University, 7141 Sherbrooke-West Street, Montreal, H4B 1R6, Canada
| | - Marcos Di Falco
- Centre for Structural & Functional Genomics, Concordia University, 7141 Sherbrooke-West Street, Montreal, H4B 1R6, Canada
| | - Thi Truc Minh Nguyen
- Centre for Structural & Functional Genomics, Concordia University, 7141 Sherbrooke-West Street, Montreal, H4B 1R6, Canada
| | - Alexander Holm Viborg
- Michael Smith Laboratories, University of British Columbia, 2185 East Mall, Vancouver, BC, V6T 1Z4, Canada
| | - Adrian Tsang
- Centre for Structural & Functional Genomics, Concordia University, 7141 Sherbrooke-West Street, Montreal, H4B 1R6, Canada
| | - Emma Master
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, ON, M5S 3E5, Canada.
- Department of Bioproducts and Biosystems, Aalto University, Kemistintie 1, 02150, Espoo, Finland.
| | - Harry Brumer
- Michael Smith Laboratories, University of British Columbia, 2185 East Mall, Vancouver, BC, V6T 1Z4, Canada.
- BioProducts Institute, University of British Columbia, 2385 East Mall, Vancouver, BC, V6T 1Z4, Canada.
- Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, BC, V6T 1Z1, Canada.
- Department of Biochemistry and Molecular Biology, University of British Columbia, 2350 Health Sciences Mall, Vancouver, BC, V6T 1Z3, Canada.
- Department of Botany, University of British Columbia, 3200 University Boulevard, Vancouver, BC, V6T 1Z4, Canada.
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Su X, Yan S, Zhao W, Liu H, Jiang Q, Wei Y, Guo H, Yin M, Shen J, Cheng H. Self-assembled thiophanate-methyl/star polycation complex prevents plant cell-wall penetration and fungal carbon utilization during cotton infection by Verticillium dahliae. Int J Biol Macromol 2023; 239:124354. [PMID: 37028625 DOI: 10.1016/j.ijbiomac.2023.124354] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Revised: 03/23/2023] [Accepted: 04/03/2023] [Indexed: 04/08/2023]
Abstract
No effective fungicides are available for the management of Verticillium dahliae, which causes vascular wilt disease. In this study, a star polycation (SPc)-based nanodelivery system was used for the first time to develop a thiophanate-methyl (TM) nanoagent for the management of V. dahliae. SPc spontaneously assembled with TM through hydrogen bonding and Van der Waals forces to decrease the particle size of TM from 834 to 86 nm. Compared to TM alone, the SPc-loaded TM further reduced the colony diameter of V. dahliae to 1.12 and 0.64 cm, and the spore number to 1.13 × 108 and 0.72 × 108 cfu/mL at the concentrations of 3.77 and 4.71 mg/L, respectively. The TM nanoagents disturbed the expression of various crucial genes in V. dahliae, and contributed to preventing plant cell-wall degradation and carbon utilization by V. dahliae, which mainly impaired the infective interaction between pathogens and plants. TM nanoagents remarkably decreased the plant disease index and the fungal biomass in the root compared to TM alone, and its control efficacy was the best (61.20 %) among the various formulations tested in the field. Furthermore, SPc showed negligible acute toxicity toward cotton seeds. To the best of our knowledge, this study is the first to design a self-assembled nanofungicide that efficiently inhibits V. dahliae growth and protects cotton from the destructive Verticillium wilt.
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Affiliation(s)
- Xiaofeng Su
- Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, PR China; Western Agricultural Research Center, Chinese Academy of Agricultural Sciences, Changji 831100, PR China
| | - Shuo Yan
- Department of Plant Biosecurity and MARA Key Laboratory of Surveillance and Management for Plant Quarantine Pests, College of Plant Protection, China Agricultural University, Beijing 100193, PR China.
| | - Weisong Zhao
- Institute of Plant Protection, Hebei Academy of Agriculture and Forestry Sciences, Baoding 071000, PR China
| | - Haiyang Liu
- Institute of Plant Protection, Xinjiang Academy of Agricultural Sciences, Urumqi 830091, PR China
| | - Qinhong Jiang
- Department of Plant Biosecurity and MARA Key Laboratory of Surveillance and Management for Plant Quarantine Pests, College of Plant Protection, China Agricultural University, Beijing 100193, PR China
| | - Ying Wei
- Department of Plant Biosecurity and MARA Key Laboratory of Surveillance and Management for Plant Quarantine Pests, College of Plant Protection, China Agricultural University, Beijing 100193, PR China
| | - Huiming Guo
- Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, PR China; Western Agricultural Research Center, Chinese Academy of Agricultural Sciences, Changji 831100, PR China
| | - Meizhen Yin
- State Key Laboratory of Chemical Resource Engineering, Beijing Lab of Biomedical Materials, Beijing University of Chemical Technology, Beijing 100029, PR China
| | - Jie Shen
- Department of Plant Biosecurity and MARA Key Laboratory of Surveillance and Management for Plant Quarantine Pests, College of Plant Protection, China Agricultural University, Beijing 100193, PR China.
| | - Hongmei Cheng
- Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, PR China; Western Agricultural Research Center, Chinese Academy of Agricultural Sciences, Changji 831100, PR China.
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11
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Wang L, Xie Y, Chang J, Wang J, Liu H, Shi M, Zhong Y. A novel sucrose-inducible expression system and its application for production of biomass-degrading enzymes in Aspergillus niger. BIOTECHNOLOGY FOR BIOFUELS AND BIOPRODUCTS 2023; 16:23. [PMID: 36782304 PMCID: PMC9926565 DOI: 10.1186/s13068-023-02274-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/10/2022] [Accepted: 01/30/2023] [Indexed: 02/15/2023]
Abstract
BACKGROUND Filamentous fungi are extensively exploited as important enzyme producers due to the superior secretory capability. However, the complexity of their secretomes greatly impairs the titer and purity of heterologous enzymes. Meanwhile, high-efficient evaluation and production of bulk enzymes, such as biomass-degrading enzymes, necessitate constructing powerful expression systems for bio-refinery applications. RESULTS A novel sucrose-inducible expression system based on the host strain Aspergillus niger ATCC 20611 and the β-fructofuranosidase promoter (PfopA) was constructed. A. niger ATCC 20611 preferentially utilized sucrose for rapid growth and β-fructofuranosidase production. Its secretory background was relatively clean because β-fructofuranosidase, the key enzyme responsible for sucrose utilization, was essentially not secreted into the medium and the extracellular protease activity was low. Furthermore, the PfopA promoter showed a sucrose concentration-dependent induction pattern and was not subject to glucose repression. Moreover, the strength of PfopA was 7.68-fold higher than that of the commonly used glyceraldehyde-3-phosphate dehydrogenase promoter (PgpdA) with enhanced green fluorescence protein (EGFP) as a reporter. Thus, A. niger ATCC 20611 coupled with the PfopA promoter was used as an expression system to express a β-glucosidase gene (bgla) from A. niger C112, allowing the production of β-glucosidase at a titer of 17.84 U/mL. The crude β-glucosidase preparation could remarkably improve glucose yield in the saccharification of pretreated corncob residues when added to the cellulase mixture of Trichoderma reesei QM9414. The efficacy of this expression system was further demonstrated by co-expressing the T. reesei-derived chitinase Chi46 and β-N-acetylglucosaminidase Nag1 to obtain an efficient chitin-degrading enzyme cocktail, which could achieve the production of N-acetyl-D-glucosamine from colloidal chitin with a conversion ratio of 91.83%. Besides, the purity of the above-secreted biomass-degrading enzymes in the crude culture supernatant was over 86%. CONCLUSIONS This PfopA-driven expression system expands the genetic toolbox of A. niger and broadens the application field of the traditional fructo-oligosaccharides-producing strain A. niger ATCC 20611, advancing it to become a high-performing enzyme-producing cell factory. In particular, the sucrose-inducible expression system possessed the capacity to produce biomass-degrading enzymes at a high level and evade endogenous protein interference, providing a potential purification-free enzyme production platform for bio-refinery applications.
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Affiliation(s)
- Lu Wang
- grid.27255.370000 0004 1761 1174State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao, 266237 People’s Republic of China
| | - Yijia Xie
- Qingdao Academy, Qingdao, 266111 People’s Republic of China
| | - Jingjing Chang
- grid.27255.370000 0004 1761 1174State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao, 266237 People’s Republic of China
| | - Juan Wang
- grid.27255.370000 0004 1761 1174State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao, 266237 People’s Republic of China
| | - Hong Liu
- grid.27255.370000 0004 1761 1174State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao, 266237 People’s Republic of China
| | - Mei Shi
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao, 266237, People's Republic of China.
| | - Yaohua Zhong
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao, 266237, People's Republic of China.
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12
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Raghav D, Jyoti A, Siddiqui AJ, Saxena J. Plant associated endophytic fungi as potential bio-factories for extracellular enzymes: Progress, Challenges and Strain improvement with precision approaches. J Appl Microbiol 2022; 133:287-310. [PMID: 35396804 DOI: 10.1111/jam.15574] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Revised: 03/04/2022] [Accepted: 04/04/2022] [Indexed: 11/29/2022]
Abstract
There is an intricate network of relations between endophytic fungi and their hosts that affects the production of various bioactive compounds. Plant-associated endophytic contain industrially important enzymes and have the potential to fulfill their rapid demand in the international market to boost business in technology. Being safe and metabolically active, they have replaced the usage of toxic and harmful chemicals and hold a credible application in biotransformation, bioremediation, and industrial processes. Despite these, there are limited reports on fungal endophytes that can directly cater to the demand and supply of industrially stable enzymes. The underlying reasons include low endogenous production and secretion of enzymes from fungal endophytes which have raised concern for widely accepted applications. Hence it is imperative to augment the biosynthetic and secretory potential of fungal endophytes. Modern state-of-the-art biotechnological technologies aiming at strain improvement using cell factory engineering as well as precise gene editing like Clustered Regularly Interspaced Palindromic Repeats (CRISPR) and its Associated proteins (Cas) systems which can provide a boost in fungal endophyte enzyme production. Additionally, it is vital to characterize optimum conditions to grow one strain with multiple enzymes (OSME). The present review encompasses various plants-derived endophytic fungal enzymes and their applications in various sectors. Further, we postulate the feasibility of new precision approaches with an aim for strain improvement and enhanced enzyme production.
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Affiliation(s)
- Divyangi Raghav
- Faculty of Applied Sciences and Biotechnology, Shoolini University of Biotechnology and Management Sciences, Solan, Himachal Pradesh, India
| | - Anupam Jyoti
- Faculty of Applied Sciences and Biotechnology, Shoolini University of Biotechnology and Management Sciences, Solan, Himachal Pradesh, India.,Department of Biotechnology, University Institute of Biotechnology, Chandigarh University, SAS, Nagar, Punjab
| | - Arif Jamal Siddiqui
- Department of Biology, College of Science, University of Ha'il, Ha'il, P O Box, Saudi Arabia
| | - Juhi Saxena
- Faculty of Applied Sciences and Biotechnology, Shoolini University of Biotechnology and Management Sciences, Solan, Himachal Pradesh, India.,Department of Biotechnology, University Institute of Biotechnology, Chandigarh University, SAS, Nagar, Punjab
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13
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Lübeck M, Lübeck PS. Fungal Cell Factories for Efficient and Sustainable Production of Proteins and Peptides. Microorganisms 2022; 10:microorganisms10040753. [PMID: 35456803 PMCID: PMC9025306 DOI: 10.3390/microorganisms10040753] [Citation(s) in RCA: 29] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Revised: 03/24/2022] [Accepted: 03/28/2022] [Indexed: 01/12/2023] Open
Abstract
Filamentous fungi are a large and diverse taxonomically group of microorganisms found in all habitats worldwide. They grow as a network of cells called hyphae. Since filamentous fungi live in very diverse habitats, they produce different enzymes to degrade material for their living, for example hydrolytic enzymes to degrade various kinds of biomasses. Moreover, they produce defense proteins (antimicrobial peptides) and proteins for attaching surfaces (hydrophobins). Many of them are easy to cultivate in different known setups (submerged fermentation and solid-state fermentation) and their secretion of proteins and enzymes are often much larger than what is seen from yeast and bacteria. Therefore, filamentous fungi are in many industries the preferred production hosts of different proteins and enzymes. Edible fungi have traditionally been used as food, such as mushrooms or in fermented foods. New trends are to use edible fungi to produce myco-protein enriched foods. This review gives an overview of the different kinds of proteins, enzymes, and peptides produced by the most well-known fungi used as cell factories for different purposes and applications. Moreover, we describe some of the challenges that are important to consider when filamentous fungi are optimized as efficient cell factories.
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14
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Sun Y, Qian Y, Zhang J, Yao C, Wang Y, Liu H, Zhong Y. Development of a novel expression platform for heterologous protein production via deleting the p53-like regulator Vib1 in Trichoderma reesei. Enzyme Microb Technol 2022; 155:109993. [DOI: 10.1016/j.enzmictec.2022.109993] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2021] [Revised: 01/03/2022] [Accepted: 01/11/2022] [Indexed: 02/06/2023]
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15
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Yoshimura Y, Kobayashi Y, Kawaguchi T, Tani S. Improvement of cellulosic biomass-degrading enzyme production by reducing extracellular protease production in <i>Aspergillus aculeatus</i>. J GEN APPL MICROBIOL 2022; 68:143-150. [DOI: 10.2323/jgam.2021.10.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Affiliation(s)
- Yuko Yoshimura
- Graduate School of Life and Environmental Sciences, Osaka Prefecture University
| | - Yuri Kobayashi
- Graduate School of Life and Environmental Sciences, Osaka Prefecture University
| | - Takashi Kawaguchi
- Graduate School of Life and Environmental Sciences, Osaka Prefecture University
| | - Shuji Tani
- Graduate School of Life and Environmental Sciences, Osaka Prefecture University
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16
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Huang L, Li X, Dong L, Wang B, Pan L. Profiling of chromatin accessibility identifies transcription factor binding sites across the genome of Aspergillus species. BMC Biol 2021; 19:189. [PMID: 34488759 PMCID: PMC8419926 DOI: 10.1186/s12915-021-01114-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Accepted: 08/02/2021] [Indexed: 12/30/2022] Open
Abstract
Background The identification of open chromatin regions and transcription factor binding sites (TFBs) is an important step in understanding the regulation of gene expression in diverse species. ATAC-seq is a technique used for such purpose by providing high-resolution measurements of chromatin accessibility revealed through integration of Tn5 transposase. However, the existence of cell walls in filamentous fungi and associated difficulty in purifying nuclei have precluded the routine application of this technique, leading to a lack of experimentally determined and computationally inferred data on the identity of genome-wide cis-regulatory elements (CREs) and TFBs. In this study, we constructed an ATAC-seq platform suitable for filamentous fungi and generated ATAC-seq libraries of Aspergillus niger and Aspergillus oryzae grown under a variety of conditions. Results We applied the ATAC-seq assay for filamentous fungi to delineate the syntenic orthologue and differentially changed chromatin accessibility regions among different Aspergillus species, during different culture conditions, and among specific TF-deleted strains. The syntenic orthologues of accessible regions were responsible for the conservative functions across Aspergillus species, while regions differentially changed between culture conditions and TFs mutants drove differential gene expression programs. Importantly, we suggest criteria to determine TFBs through the analysis of unbalanced cleavage of distinct TF-bound DNA strands by Tn5 transposase. Based on this criterion, we constructed data libraries of the in vivo genomic footprint of A. niger under distinct conditions, and generated a database of novel transcription factor binding motifs through comparison of footprints in TF-deleted strains. Furthermore, we validated the novel TFBs in vivo through an artificial synthetic minimal promoter system. Conclusions We characterized the chromatin accessibility regions of filamentous fungi species, and identified a complete TFBs map by ATAC-seq, which provides valuable data for future analyses of transcriptional regulation in filamentous fungi. Supplementary Information The online version contains supplementary material available at 10.1186/s12915-021-01114-0.
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Affiliation(s)
- Lianggang Huang
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou Higher Education Mega Center, Guangzhou, 510006, China
| | - Xuejie Li
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou Higher Education Mega Center, Guangzhou, 510006, China
| | - Liangbo Dong
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou Higher Education Mega Center, Guangzhou, 510006, China
| | - Bin Wang
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou Higher Education Mega Center, Guangzhou, 510006, China. .,Guangdong Provincial Key Laboratory of Fermentation and Enzyme Engineering, South China University of Technology, Guangzhou Higher Education Mega Center, Guangzhou, 510006, China.
| | - Li Pan
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou Higher Education Mega Center, Guangzhou, 510006, China. .,Guangdong Provincial Key Laboratory of Fermentation and Enzyme Engineering, South China University of Technology, Guangzhou Higher Education Mega Center, Guangzhou, 510006, China.
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17
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Kun RS, Garrigues S, Di Falco M, Tsang A, de Vries RP. Blocking utilization of major plant biomass polysaccharides leads Aspergillus niger towards utilization of minor components. Microb Biotechnol 2021; 14:1683-1698. [PMID: 34114741 PMCID: PMC8313289 DOI: 10.1111/1751-7915.13835] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Revised: 05/08/2021] [Accepted: 05/10/2021] [Indexed: 11/28/2022] Open
Abstract
Fungi produce a wide range of enzymes that allow them to grow on diverse plant biomass. Wheat bran is a low-cost substrate with high potential for biotechnological applications. It mainly contains cellulose and (arabino)xylan, as well as starch, proteins, lipids and lignin to a lesser extent. In this study, we dissected the regulatory network governing wheat bran degradation in Aspergillus niger to assess the relative contribution of the regulators to the utilization of this plant biomass substrate. Deletion of genes encoding transcription factors involved in (hemi-)cellulose utilization (XlnR, AraR, ClrA and ClrB) individually and in combination significantly reduced production of polysaccharide-degrading enzymes, but retained substantial growth on wheat bran. Proteomic analysis suggested the ability of A. niger to grow on other carbon components, such as starch, which was confirmed by the additional deletion of the amylolytic regulator AmyR. Growth was further reduced but not impaired, indicating that other minor components provide sufficient energy for residual growth, displaying the flexibility of A. niger, and likely other fungi, in carbon utilization. Better understanding of the complexity and flexibility of fungal regulatory networks will facilitate the generation of more efficient fungal cell factories that use plant biomass as a substrate.
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Affiliation(s)
- Roland S. Kun
- Fungal PhysiologyWesterdijk Fungal Biodiversity Institute & Fungal Molecular PhysiologyUtrecht UniversityUppsalalaan 8Utrecht3584 CTThe Netherlands
| | - Sandra Garrigues
- Fungal PhysiologyWesterdijk Fungal Biodiversity Institute & Fungal Molecular PhysiologyUtrecht UniversityUppsalalaan 8Utrecht3584 CTThe Netherlands
| | - Marcos Di Falco
- Centre for Structural and Functional GenomicsConcordia University7141 Sherbrooke Street WestMontrealQCH4B 1R6Canada
| | - Adrian Tsang
- Centre for Structural and Functional GenomicsConcordia University7141 Sherbrooke Street WestMontrealQCH4B 1R6Canada
| | - Ronald P. de Vries
- Fungal PhysiologyWesterdijk Fungal Biodiversity Institute & Fungal Molecular PhysiologyUtrecht UniversityUppsalalaan 8Utrecht3584 CTThe Netherlands
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18
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Araki Y, Yuzuki M, Masakari Y, Sato A, Gomi K, Hara S. High-level heterologous protein production using an attenuated selection marker in Aspergillus sojae. J GEN APPL MICROBIOL 2021; 67:77-80. [PMID: 33298630 DOI: 10.2323/jgam.2020.05.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Filamentous fungi, including Aspergillus sojae, are essential for the industrial production of enzymes. Although multi-copy introduction of a gene encoding the protein of interest is useful for increasing protein production, this method has not been established in the case of filamentous fungi. In this study, we aimed to establish an efficient system for multi-copy chromosomal integration and high-level expression of a heterologous gene in A. sojae using an attenuated selectable marker. Consequently, by truncating the promoter region of selectable markers, we efficiently introduced multiple copies of a heterologous gene and enhanced the rate of high-level protein-production in the strains. Since the multi-copy strains obtained in this study maintained high productivity even in a non-selective medium, this system could be applicable for industrial protein production.
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Affiliation(s)
- Yasuko Araki
- Research and Development Division, Kikkoman Corporation
| | | | | | - Atsushi Sato
- Research and Development Division, Kikkoman Corporation
| | - Keiko Gomi
- Research and Development Division, Kikkoman Corporation
| | - Seiichi Hara
- Research and Development Division, Kikkoman Corporation
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19
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Tanaka M, Gomi K. Induction and Repression of Hydrolase Genes in Aspergillus oryzae. Front Microbiol 2021; 12:677603. [PMID: 34108952 PMCID: PMC8180590 DOI: 10.3389/fmicb.2021.677603] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Accepted: 04/26/2021] [Indexed: 11/13/2022] Open
Abstract
The filamentous fungus Aspergillus oryzae, also known as yellow koji mold, produces high levels of hydrolases such as amylolytic and proteolytic enzymes. This property of producing large amounts of hydrolases is one of the reasons why A. oryzae has been used in the production of traditional Japanese fermented foods and beverages. A wide variety of hydrolases produced by A. oryzae have been used in the food industry. The expression of hydrolase genes is induced by the presence of certain substrates, and various transcription factors that regulate such expression have been identified. In contrast, in the presence of glucose, the expression of the glycosyl hydrolase gene is generally repressed by carbon catabolite repression (CCR), which is mediated by the transcription factor CreA and ubiquitination/deubiquitination factors. In this review, we present the current knowledge on the regulation of hydrolase gene expression, including CCR, in A. oryzae.
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Affiliation(s)
- Mizuki Tanaka
- Biomolecular Engineering Laboratory, School of Food and Nutritional Science, University of Shizuoka, Shizuoka, Japan
| | - Katsuya Gomi
- Laboratory of Fermentation Microbiology, Graduate School of Agricultural Science, Tohoku University, Sendai, Japan
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20
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Ge LY, Liu J, Zheng HL, Mei H, Liang GZ, Liu WD. Comprehensive genome and transcriptome analysis of the dermatophyte Trichophyton schoenleinii reveals the candidate pathogenic genes. Mycoses 2021; 64:624-633. [PMID: 33586267 DOI: 10.1111/myc.13257] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Revised: 02/06/2021] [Accepted: 02/08/2021] [Indexed: 11/27/2022]
Abstract
BACKGROUND Trichophyton schoenleinii is an anthropophilic dermatophyte that causes tinea favosa. Nowadays, it remains an important pathogen in some regions of the world, mainly epidemic in Africa and West Asia. Despite the medical importance of T. schoenleinii infections, a high-quality reference genome for T. schoenleinii is still unavailable, neither its transcriptomic profile. OBJECTIVES The aim of the current study was to improve understanding of the underlying pathogenic mechanism of T. schoenleinii, and to define the candidate pathogenic genes of T. schoenleinii. METHODS Comprehensive genomic analysis of T. schoenleinii was carried out by Illumina and PacBio sequencing platforms. Transcriptome profiles of T. schoenleinii cultured in vitro in two media containing either keratin or soy protein were determined using RNA sequencing (RNA-seq) technology. RESULTS Here, we present the first draft genome sequence of T. schoenleinii strain T2s, which consists of 11 scaffolds containing 7474 predicted genes. Transcriptome analysis showed that genes involved in keratin hydrolysis have higher expression in T. schoenleinii grown in keratin medium, including genes encoding proteases, cysteine dioxygenase and acetamidase. Other genes with higher expression include genes encoding the components of the pH-responsive signal transduction pathways and transcription factors, many of which may play a role in pathogenicity. CONCLUSION In summary, this study provides new insights into the pathogenic mechanism of T. schoenleinii and highlights candidate genes for further development of novel targets in disease diagnosis and treatment of tinea favosa.
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Affiliation(s)
- Li-Yu Ge
- Department of Medical Mycology, Institute of Dermatology, Chinese Academy of Medical Sciences and Peking Union Medical College, Nanjing, China
| | - Jia Liu
- Department of Medical Mycology, Institute of Dermatology, Chinese Academy of Medical Sciences and Peking Union Medical College, Nanjing, China.,Department of Dermatology, the First Affiliated Hospital of Nanjing Medical University, Nanjing, China
| | - Hai-Lin Zheng
- Department of Medical Mycology, Institute of Dermatology, Chinese Academy of Medical Sciences and Peking Union Medical College, Nanjing, China.,Jiangsu Key Laboratory of Molecular Biology for Skin Diseases and STIs, Nanjing, China
| | - Huan Mei
- Department of Medical Mycology, Institute of Dermatology, Chinese Academy of Medical Sciences and Peking Union Medical College, Nanjing, China.,Jiangsu Key Laboratory of Molecular Biology for Skin Diseases and STIs, Nanjing, China
| | - Guan-Zhao Liang
- Department of Medical Mycology, Institute of Dermatology, Chinese Academy of Medical Sciences and Peking Union Medical College, Nanjing, China.,Jiangsu Key Laboratory of Molecular Biology for Skin Diseases and STIs, Nanjing, China
| | - Wei-Da Liu
- Department of Medical Mycology, Institute of Dermatology, Chinese Academy of Medical Sciences and Peking Union Medical College, Nanjing, China.,Jiangsu Key Laboratory of Molecular Biology for Skin Diseases and STIs, Nanjing, China.,Center for Global Health, School of Public Health, Nanjing Medical University, Nanjing, China
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21
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Tanaka M, Ito K, Matsuura T, Kawarasaki Y, Gomi K. Identification and distinct regulation of three di/tripeptide transporters in Aspergillus oryzae. Biosci Biotechnol Biochem 2020; 85:452-463. [DOI: 10.1093/bbb/zbaa030] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Accepted: 08/26/2020] [Indexed: 12/24/2022]
Abstract
ABSTRACT
The uptake of di/tripeptides is mediated by the proton-dependent oligopeptide transporter (POT) family. In this study, 3 POT family transporters, designated PotA, PotB, and PotC were identified in Aspergillus oryzae. Growth comparison of deletion mutants of these transporter genes suggested that PotB and PotC are responsible for di/tripeptide uptake. PotA, which had the highest sequence similarity to yeast POT (Ptr2), contributed little to the uptake. Nitrogen starvation induced potB and potC expression, but not potA expression. When 3 dipeptides were provided as nitrogen sources, the expression profiles of these genes were different. PrtR, a transcription factor that regulates proteolytic genes, was involved in regulation of potA and potB but not in potC expression. Only potC expression levels were dramatically reduced by disruption of ubrA, an orthologue of yeast ubiquitin ligase UBR1 responsible for PTR2 expression. Expression of individual POT genes is apparently controlled by different regulatory mechanisms.
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Affiliation(s)
- Mizuki Tanaka
- Biomolecular Engineering Laboratory, School of Food and Nutritional Science, University of Shizuoka, Suruga-ku, Shizuoka, Japan
| | - Keisuke Ito
- Laboratory of Food Chemistry, School of Food and Nutritional Science, University of Shizuoka, Suruga-ku, Shizuoka, Japan
| | - Tomomi Matsuura
- Laboratory of Bioindustrial Genomics, Graduate School of Agricultural Science, Tohoku University, Aoba-ku, Sendai, Japan
| | - Yasuaki Kawarasaki
- Biomolecular Engineering Laboratory, School of Food and Nutritional Science, University of Shizuoka, Suruga-ku, Shizuoka, Japan
| | - Katsuya Gomi
- Laboratory of Bioindustrial Genomics, Graduate School of Agricultural Science, Tohoku University, Aoba-ku, Sendai, Japan
- Laboratory of Fermentation Microbiology, Graduate School of Agricultural Science, Tohoku University, Aoba-ku, Sendai, Japan
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22
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Abstract
Aspergilli have been widely used in the production of organic acids, enzymes, and secondary metabolites for almost a century. Today, several GRAS (generally recognized as safe) Aspergillus species hold a central role in the field of industrial biotechnology with multiple profitable applications. Since the 1990s, research has focused on the use of Aspergillus species in the development of cell factories for the production of recombinant proteins mainly due to their natively high secretion capacity. Advances in the Aspergillus-specific molecular toolkit and combination of several engineering strategies (e.g., protease-deficient strains and fusions to carrier proteins) resulted in strains able to generate high titers of recombinant fungal proteins. However, the production of non-fungal proteins appears to still be inefficient due to bottlenecks in fungal expression and secretion machinery. After a brief overview of the different heterologous expression systems currently available, this review focuses on the filamentous fungi belonging to the genus Aspergillus and their use in recombinant protein production. We describe key steps in protein synthesis and secretion that may limit production efficiency in Aspergillus systems and present genetic engineering approaches and bioprocessing strategies that have been adopted in order to improve recombinant protein titers and expand the potential of Aspergilli as competitive production platforms.
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Li C, Zhou J, Du G, Chen J, Takahashi S, Liu S. Developing Aspergillus niger as a cell factory for food enzyme production. Biotechnol Adv 2020; 44:107630. [PMID: 32919011 DOI: 10.1016/j.biotechadv.2020.107630] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2020] [Revised: 09/05/2020] [Accepted: 09/05/2020] [Indexed: 02/06/2023]
Abstract
Aspergillus niger has become one of the most important hosts for food enzyme production due to its unique food safety characteristics and excellent protein secretion systems. A series of food enzymes such as glucoamylase have been commercially produced by A. niger strains, making this species a suitable platform for the engineered of strains with improved enzyme production. However, difficulties in genetic manipulations and shortage of expression strategies limit the progress in this regard. Moreover, several mycotoxins have recently been detected in some A. niger strains, which raises the necessity for a regulatory approval process for food enzyme production. With robust strains, processing engineering strategies are also needed for producing the enzymes on a large scale, which is also challenging for A. niger, since its culture is aerobic, and non-Newtonian fluid properties are developed during submerged culture, making mixing and aeration very energy-intensive. In this article, the progress and challenges of developing A. niger for the production of food enzymes are reviewed, including its genetic manipulations, strategies for more efficient production of food enzymes, and elimination of mycotoxins for product safety.
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Affiliation(s)
- Cen Li
- National Engineering Laboratory for Cereal Fermentation Technology, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu 214122, China; School of Biotechnology and Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu 214122, China.
| | - Jingwen Zhou
- National Engineering Laboratory for Cereal Fermentation Technology, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu 214122, China; School of Biotechnology and Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu 214122, China; Jiangsu Provisional Research Center for Bioactive Product Processing Technology, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu 214122, China.
| | - Guocheng Du
- School of Biotechnology and Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu 214122, China; The Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu 214122, China.
| | - Jian Chen
- National Engineering Laboratory for Cereal Fermentation Technology, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu 214122, China; School of Biotechnology and Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu 214122, China; Jiangsu Provisional Research Center for Bioactive Product Processing Technology, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu 214122, China.
| | - Shunji Takahashi
- Natural Product Biosynthesis Research Unit, RIKEN Center for Sustainable Resource Science, 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan.
| | - Song Liu
- National Engineering Laboratory for Cereal Fermentation Technology, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu 214122, China; School of Biotechnology and Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu 214122, China.
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Daranagama ND, Suzuki Y, Shida Y, Ogasawara W. Involvement of Xyr1 and Are1 for Trichodermapepsin Gene Expression in Response to Cellulose and Galactose in Trichoderma reesei. Curr Microbiol 2020; 77:1506-1517. [DOI: 10.1007/s00284-020-01955-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Accepted: 03/18/2020] [Indexed: 10/24/2022]
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25
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Jørgensen TR, Burggraaf AM, Arentshorst M, Schutze T, Lamers G, Niu J, Kwon MJ, Park J, Frisvad JC, Nielsen KF, Meyer V, van den Hondel CA, Dyer PS, Ram AF. Identification of SclB, a Zn(II)2Cys6 transcription factor involved in sclerotium formation in Aspergillus niger. Fungal Genet Biol 2020; 139:103377. [DOI: 10.1016/j.fgb.2020.103377] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2019] [Revised: 02/07/2020] [Accepted: 02/14/2020] [Indexed: 10/24/2022]
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26
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Rojas-Sánchez U, López-Calleja AC, Millán-Chiu BE, Fernández F, Loske AM, Gómez-Lim MA. Enhancing the yield of human erythropoietin in Aspergillus niger by introns and CRISPR-Cas9. Protein Expr Purif 2020; 168:105570. [DOI: 10.1016/j.pep.2020.105570] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Revised: 01/12/2020] [Accepted: 01/13/2020] [Indexed: 12/14/2022]
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27
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Xie H, Ma Q, Wei D, Wang F. Metabolic engineering of an industrial Aspergillus niger strain for itaconic acid production. 3 Biotech 2020; 10:113. [PMID: 32117674 DOI: 10.1007/s13205-020-2080-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Accepted: 01/20/2020] [Indexed: 02/04/2023] Open
Abstract
Itaconic acid is a value-added organic acid that is widely applied in industrial production. It can be converted from citric acid by some microorganisms including Aspergillus terreus and Aspergillus niger. Because of high citric acid production (more than 200 g/L), A. niger strains may be developed into powerful itaconic acid-producing microbial cell factories. In this study, industrial citric acid-producing strain A. niger YX-1217, capable of producing 180.0-200.0 g/L, was modified to produce itaconic acid by metabolic engineering. A key gene cadA encoding aconitase was expressed in A. niger YX-1217 under the control of three different promoters. Analyses showed that the PglaA promoter resulted in higher levels of gene expression than the PpkiA and PgpdA promoters. Moreover, the synthesis pathway of itaconic acid was extended by introducing the acoA gene, and the cadA gene, encoding aconitate decarboxylase, into A. niger YX-1217 under the function of the two rigid short-peptide linkers L1 or L2. The resulting recombinant strains L-1 and L-2 were induced to produce itaconic acid in fed-batch fermentations under three-stage control of agitation speed. After fermentation for 104 h, itaconic acid concentrations in the recombinant strain L-2 culture reached 7.2 g/L, which represented a 71.4% increase in itaconic acid concentration compared with strain Z-17 that only expresses cadA. Therefore, co-expression of acoA and cadA resulted in an extension of the citric acid metabolic pathway to the itaconic acid metabolic pathway, thereby increasing the production of itaconic acid by A. niger.
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Affiliation(s)
- Hui Xie
- 1State Key Lab of Bioreactor Engineering, Newworld Institute of Biotechnology, East China University of Science and Technology, Shanghai, 200237 China
- 2Life Science College, Henan Agricultural University, Zhengzhou, 450002 China
| | - Qinyuan Ma
- Weifang Ensign Industry Co., Ltd, Weifang, 262499 China
| | - Dongzhi Wei
- 1State Key Lab of Bioreactor Engineering, Newworld Institute of Biotechnology, East China University of Science and Technology, Shanghai, 200237 China
| | - Fengqing Wang
- 1State Key Lab of Bioreactor Engineering, Newworld Institute of Biotechnology, East China University of Science and Technology, Shanghai, 200237 China
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28
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Huang L, Dong L, Wang B, Pan L. The transcription factor PrtT and its target protease profiles in Aspergillus niger are negatively regulated by carbon sources. Biotechnol Lett 2020; 42:613-624. [PMID: 31970554 DOI: 10.1007/s10529-020-02806-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2019] [Accepted: 01/13/2020] [Indexed: 11/30/2022]
Abstract
OBJECTIVE To survey genome-scale protease profiles regulated by the Aspergillus niger transcription factor PrtT and further controlled by carbon sources. RESULTS The PrtT disruption mutant (delprtT) and overexpression (OEprtT) strains were successfully generated and further confirmed by phenotypic and protease activity analysis. RNA-seq analysis of WT and mutants identified 32 differentially expressed protease genes, which mostly belonged to serine-type peptidases, aspartic-type endopeptidases, aminopeptidases and carboxypeptidases. Furthermore, based on the MEME predicted motif analysis of the PrtT promoter, EMSA and phenotypic and qRT-PCR analyses confirmed that the carbon metabolism regulator AmyR directly regulated the protease genes and their regulatory factor PrtT. CONCLUSION Thirty-two PrtT-regulated protease genes were identified by RNA-seq, and the secondary carbon source regulator AmyR was found to have a negative regulatory effect on the expression of PrtT and its target protease genes.
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Affiliation(s)
- Lianggang Huang
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou Higher Education Mega Center, No. 382, Waihuan East Rd, Guangzhou, 510006, China
| | - Liangbo Dong
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou Higher Education Mega Center, No. 382, Waihuan East Rd, Guangzhou, 510006, China
| | - Bin Wang
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou Higher Education Mega Center, No. 382, Waihuan East Rd, Guangzhou, 510006, China.,Guangdong Provincial Key Laboratory of Fermentation and Enzyme Engineering, South China University of Technology, Guangzhou, 510006, China
| | - Li Pan
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou Higher Education Mega Center, No. 382, Waihuan East Rd, Guangzhou, 510006, China. .,Guangdong Provincial Key Laboratory of Fermentation and Enzyme Engineering, South China University of Technology, Guangzhou, 510006, China.
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29
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Nevalainen H. Strategies and Challenges for the Development of Industrial Enzymes Using Fungal Cell Factories. GRAND CHALLENGES IN FUNGAL BIOTECHNOLOGY 2020. [PMCID: PMC7123961 DOI: 10.1007/978-3-030-29541-7_7] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Industrial enzymes have been produced from microorganisms for more than a century. Today, a large share of enzyme products is manufactured using recombinant microorganisms. This chapter focuses on major industrial fungal species belonging to the ascomycetes like Aspergillus niger, A. oryzae, and Trichoderma reesei. Many of the commercially available recombinant enzymes are manufactured using fungi. Examples of fungal enzymes used in food products are described. The enzyme industry is to a large extent cost-driven, so the enzyme product needs to meet strict COGS (cost of goods sold) targets. Therefore, the cell factory must be very efficient to produce the enzyme in high titers and efficiently utilize raw materials. Secondly, it must be designed for a robust and generic fermentation process. When developing fungal hosts for enzyme production, several properties of the system need to be considered relating to efficiency of the cell factory, purity of the product, and safety of both the cell factory and the product. Purity is secured by engineering of the cell factory, and properties related to safety must also be engineered into the fungal host. The methods used for strain improvement are continuously being developed to increase yields and are described herein. More automation using precision tools for modification of the genome (i.e., CRISPR) and low-cost sequencing have vastly expanded the possibilities and enabled fast strain development. Using systems biology approaches, better understanding of cellular processes is now possible enabling advanced engineering of fungal cell factories. Surprisingly, a survey of innovation in the field revealed a decrease in the number of patent applications in recent years. Finally, the requirements for enzyme approval, especially in food and feed, have increased significantly worldwide in the last few years. A description of the regulatory landscape and its challenges in food and feed is included.
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Affiliation(s)
- Helena Nevalainen
- Department of Molecular Sciences, Macquarie University, Sydney, NSW Australia
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30
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Qian Y, Zhong L, Sun Y, Sun N, Zhang L, Liu W, Qu Y, Zhong Y. Enhancement of Cellulase Production in Trichoderma reesei via Disruption of Multiple Protease Genes Identified by Comparative Secretomics. Front Microbiol 2019; 10:2784. [PMID: 31849916 PMCID: PMC6901835 DOI: 10.3389/fmicb.2019.02784] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Accepted: 11/15/2019] [Indexed: 01/06/2023] Open
Abstract
The filamentous fungus Trichoderma reesei is one of the most studied cellulolytic organisms and the major producer of cellulases for industrial applications. However, undesired degradation of cellulases often happens in culture filtrates and commercial enzyme preparations. Even studies have been reported about describing proteolytic degradation of heterologous proteins in T. reesei, there are few systematic explorations concerning the extracellular proteases responsible for degradation of cellulases. In this study, the cellulase activity was observed to rapidly decrease at late cultivation stages using corn steep liquor (CSL) as the nitrogen source in T. reesei. It was discovered that this decrease may be caused by proteases. To identify the proteases, comparative secretomics was performed to analyze the concomitant proteases during the cellulase production. 12 candidate proteases from the secretome of T. reesei were identified and their encoding genes were individually deleted via homologous recombination. Furthermore, three target proteases (tre81070, tre120998, and tre123234) were simultaneously deleted by one-step genetic transformation. The triple deletion strain ΔP70 showed a 78% decrease in protease activity and a six-fold increase in cellulase activity at late fermentation stages. These results demonstrated the feasibility of improvement of cellulase production by genetically disrupting the potential protease genes to construct the T. reesei strains with low extracellular protease secretion. This dataset also provides an efficient approach for strain improvement by precise genetic engineering combined with "omics" strategy for high-production of industrial enzymes to reduce the cost of lignocellulose bioconversion.
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Affiliation(s)
- Yuanchao Qian
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao, China
| | - Lixia Zhong
- Shandong Institute for Food and Drug Control, Jinan, China
| | - Yu Sun
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao, China
| | - Ningning Sun
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao, China
| | - Lei Zhang
- Department of Immunology, School of Basic Medical Sciences, Shandong University, Jinan, China
| | - Weifeng Liu
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao, China
| | - Yinbo Qu
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao, China
| | - Yaohua Zhong
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao, China
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31
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Ballester AR, López-Pérez M, de la Fuente B, González-Candelas L. Functional and Pharmacological Analyses of the Role of Penicillium digitatum Proteases on Virulence. Microorganisms 2019; 7:microorganisms7070198. [PMID: 31336863 PMCID: PMC6680461 DOI: 10.3390/microorganisms7070198] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2019] [Revised: 07/08/2019] [Accepted: 07/11/2019] [Indexed: 11/16/2022] Open
Abstract
Penicillium digitatum is the major postharvest pathogen of citrus fruit under Mediterranean climate conditions. Previous results have shown that proteases is the largest enzyme family induced by P. digitatum during fruit infection. In the present work, we addressed the study of the role of P. digitatum's proteases in virulence following two complementary approaches. In the first approach, we undertook the functional characterization of the P. digitatum prtT gene, which codes for a putative transcription factor previously shown to regulate extracellular proteases in other filamentous fungi. Deletion of prtT caused a significant loss in secreted protease activity during in vitro growth assays. However, there was no effect on virulence. Gene expression of the two major secreted acid proteases was barely affected in the ΔprtT deletant during infection of citrus fruit. Hence, no conclusion could be drawn on the role of these secreted acidic proteases on the virulence of P. digitatum. In the second approach, we studied the effect of different protease inhibitors and chelators on virulence. Co-inoculation of citrus fruit with P. digitatum conidia and a cocktail of protease inhibitors resulted in almost a complete absence of disease development. Analysis of individual inhibitors revealed that the metalloprotease inhibitor, 1,10-phenanthroline, was responsible for the observed effect. The application of metal ions reverted the protective effect caused by the metallopeptidase inhibitor. These results may set the basis for the development of new alternative treatments to combat this important postharvest pathogen.
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Affiliation(s)
- Ana-Rosa Ballester
- Department of Food Biotechnology, Institute of Agrochemistry and Food Technology, Spanish National Research Council (IATA-CSIC), Calle Catedrático Agustín Escardino 7, 46980 Paterna, Valencia, Spain
| | - Mario López-Pérez
- Department of Food Biotechnology, Institute of Agrochemistry and Food Technology, Spanish National Research Council (IATA-CSIC), Calle Catedrático Agustín Escardino 7, 46980 Paterna, Valencia, Spain
| | - Beatriz de la Fuente
- Department of Food Biotechnology, Institute of Agrochemistry and Food Technology, Spanish National Research Council (IATA-CSIC), Calle Catedrático Agustín Escardino 7, 46980 Paterna, Valencia, Spain
| | - Luis González-Candelas
- Department of Food Biotechnology, Institute of Agrochemistry and Food Technology, Spanish National Research Council (IATA-CSIC), Calle Catedrático Agustín Escardino 7, 46980 Paterna, Valencia, Spain.
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32
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Davy AM, Kildegaard HF, Andersen MR. Cell Factory Engineering. Cell Syst 2019; 4:262-275. [PMID: 28334575 DOI: 10.1016/j.cels.2017.02.010] [Citation(s) in RCA: 70] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2015] [Revised: 11/11/2016] [Accepted: 02/15/2017] [Indexed: 11/30/2022]
Abstract
Rational approaches to modifying cells to make molecules of interest are of substantial economic and scientific interest. Most of these efforts aim at the production of native metabolites, expression of heterologous biosynthetic pathways, or protein expression. Reviews of these topics have largely focused on individual strategies or cell types, but collectively they fall under the broad umbrella of a growing field known as cell factory engineering. Here we condense >130 reviews and key studies in the art into a meta-review of cell factory engineering. We identified 33 generic strategies in the field, all applicable to multiple types of cells and products, and proven successful in multiple major cell types. These apply to three major categories: production of native metabolites and/or bioactives, heterologous expression of biosynthetic pathways, and protein expression. This meta-review provides general strategy guides for the broad range of applications of rational engineering of cell factories.
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Affiliation(s)
- Anne Mathilde Davy
- Department of Biotechnology and Biomedicine, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark
| | - Helene Faustrup Kildegaard
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark
| | - Mikael Rørdam Andersen
- Department of Biotechnology and Biomedicine, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark.
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33
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Gomi K. Regulatory mechanisms for amylolytic gene expression in the koji mold Aspergillus oryzae. Biosci Biotechnol Biochem 2019; 83:1385-1401. [PMID: 31159661 DOI: 10.1080/09168451.2019.1625265] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
The koji mold Aspergillus oryzae has been used in traditional Japanese food and beverage fermentation for over a thousand years. Amylolytic enzymes are important in sake fermentation, wherein production is induced by starch or malto-oligosaccharides. This inducible production requires at least two transcription activators, AmyR and MalR. Among amylolytic enzymes, glucoamylase GlaB is produced exclusively in solid-state culture and plays a critical role in sake fermentation owing to its contribution to glucose generation from starch. A recent study demonstrated that glaB gene expression is regulated by a novel transcription factor, FlbC, in addition to AmyR in solid-state culture. Amylolytic enzyme production is generally repressed by glucose due to carbon catabolite repression (CCR), which is mediated by the transcription factor CreA. Modifying CCR machinery, including CreA, can improve amylolytic enzyme production. This review focuses on the role of transcription factors in regulating A. oryzae amylolytic gene expression.
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Affiliation(s)
- Katsuya Gomi
- a Laboratory of Fermentation Microbiology, Graduate School of Agricultural Science , Tohoku University , Sendai , Japan
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34
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Snyman C, Theron LW, Divol B. Understanding the regulation of extracellular protease gene expression in fungi: a key step towards their biotechnological applications. Appl Microbiol Biotechnol 2019; 103:5517-5532. [PMID: 31129742 DOI: 10.1007/s00253-019-09902-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2019] [Revised: 05/07/2019] [Accepted: 05/07/2019] [Indexed: 12/20/2022]
Abstract
The secretion of proteases by certain species of yeast and filamentous fungi is of importance not only for their biological function and survival, but also for their biotechnological application to various processes in the food, beverage, and bioprocessing industries. A key step towards understanding the role that these organisms play in their environment, and how their protease-secreting ability may be optimally utilised through industrial applications, involves an evaluation of those factors which influence protease production. The objective of this review is to provide an overview of the findings from investigations directed at elucidating the regulatory mechanisms underlying extracellular protease secretion in yeast and filamentous fungi, and the environmental stimuli that elicit these responses. The influence of nitrogen-, carbon-, and sulphur-containing compounds, as well as proteins, temperature, and pH, on extracellular protease regulation, which is frequently exerted at the transcriptional level, is discussed in particular depth. Protease-secreting organisms of biotechnological interest are also presented in this context, in an effort to explore the areas of industrial significance that could possibly benefit from such knowledge. In this way, the establishment of a platform of existing knowledge regarding fungal protease regulation is attempted, with the particular goal of aiding in the practical application of these organisms to processes that require secretion of this enzyme.
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Affiliation(s)
- C Snyman
- Department of Viticulture and Oenology, Institute for Wine Biotechnology, Private Bag X1, Matieland, 7602, South Africa
| | - L W Theron
- Department of Viticulture and Oenology, Institute for Wine Biotechnology, Private Bag X1, Matieland, 7602, South Africa
| | - B Divol
- Department of Viticulture and Oenology, Institute for Wine Biotechnology, Private Bag X1, Matieland, 7602, South Africa.
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35
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Takahashi T, Ogawa M, Sato A, Koyama Y. Translocated duplication of a targeted chromosomal segment enhances gene expression at the duplicated site and results in phenotypic changes in Aspergillus oryzae. Fungal Biol Biotechnol 2018; 5:17. [PMID: 30305913 PMCID: PMC6171174 DOI: 10.1186/s40694-018-0061-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2018] [Accepted: 09/21/2018] [Indexed: 11/30/2022] Open
Abstract
Background Translocated chromosomal duplications occur spontaneously in many organisms; segmental duplications of large chromosomal regions are expected to result in phenotypic changes because of gene dosage effects. Therefore, experimentally generated segmental duplications in targeted chromosomal regions can be used to study phenotypic changes and determine the functions of unknown genes in these regions. Previously, we performed tandem duplication of a targeted chromosomal segment in Aspergillus oryzae. However, in tandem chromosomal duplication, duplication of chromosomal ends and multiple chromosomal duplication are difficult. In this study, we aimed to generate fungal strains with a translocated duplication or triplication of a targeted chromosomal region via break-induced replication. Results Double-strand breaks were introduced into chromosomes of parental strains by treating protoplast cells with I-SceI meganuclease. Subsequently, strains were generated by nonreciprocal translocation of a 1.4-Mb duplicated region of chromosome 2 to the end of chromosome 4. Another strain, containing a triplicated region of chromosome 2, was generated by translocating a 1.4-Mb region of chromosome 2 onto the ends of chromosomes 4 and 7. Phenotypic analyses of the strains containing segmental duplication or triplication of chromosome 2 showed remarkable increases in protease and amylase activities in solid-state cultures. Protease activity was further increased in strains containing the duplication and triplication after overexpression of the transcriptional activator of proteases prtT. This indicates that the gene-dosage effect and resulting phenotypes of the duplicated chromosomal region were enhanced by multiple duplications, and by the combination of the structural gene and its regulatory genes. Gene expression analysis, conducted using oligonucleotide microarrays, showed increased transcription of a large population of genes located in duplicated or triplicated chromosomal regions. Conclusion In this study, we performed translocated chromosomal duplications and triplications of a 1.4-Mb targeted region of chromosome 2. Strains containing a duplication of chromosome 2 showed significant increases in protease and amylase activities; these enzymatic activities were further increased in the strain containing a triplication of chromosome 2. This indicates that segmental duplications of chromosomes enhance gene-dosage effects, and that the resulting phenotypes play important phenotypic roles in A. oryzae. Electronic supplementary material The online version of this article (10.1186/s40694-018-0061-6) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Tadashi Takahashi
- Noda Institute for Scientific Research, 399 Noda, Noda City, Chiba Pref 278-0037 Japan
| | - Masahiro Ogawa
- Noda Institute for Scientific Research, 399 Noda, Noda City, Chiba Pref 278-0037 Japan
| | - Atsushi Sato
- Noda Institute for Scientific Research, 399 Noda, Noda City, Chiba Pref 278-0037 Japan
| | - Yasuji Koyama
- Noda Institute for Scientific Research, 399 Noda, Noda City, Chiba Pref 278-0037 Japan
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36
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Zhao G, Ding LL, Pan ZH, Kong DH, Hadiatullah H, Fan ZC. Proteinase and glycoside hydrolase production is enhanced in solid-state fermentation by manipulating the carbon and nitrogen fluxes in Aspergillus oryzae. Food Chem 2018; 271:606-613. [PMID: 30236722 DOI: 10.1016/j.foodchem.2018.07.199] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2018] [Revised: 07/07/2018] [Accepted: 07/25/2018] [Indexed: 02/07/2023]
Abstract
Soy sauce materials of soybean meal and wheat bran were evaluated in solid-state (koji) fermentation (SSF) and submerged fermentation (SmF) by Aspergillus oryzae. Proteinase production in SSF (2331 ± 39 U g-1) was about 4.9 times higher than that in SmF (477 ± 13 U g-1), and glycoside hydrolase was approximately 2 times higher in SSF than that in SmF. In addition, protein expression of iTRAQ analysis deepens our understanding of the secreting mechanism. Abundant proteinases (dipeptidase, dipeptidyl aminopeptidase, puromycin-sensitive aminopeptidase, Xaa-pro aminopeptidase, neutral protease 2 and leucine aminopeptidase 2), along with the glycoside hydrolase (glycoamylase, glucosidase and β-xylanase) were secreted at the late stage of SSF, but tripeptidyl peptidase sed 2 was proposed as an indispensable protease in SmF or the early stage of SSF. Several metabolites associated with the carbon flux and amino acid biosynthesis were proved to be regulated by the proteinase and glycoside hydrolase production.
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Affiliation(s)
- Guozhong Zhao
- State Key Laboratory of Food Nutrition and Safety, Key Laboratory of Food Nutrition and Safety, Ministry of Education, International Collaborative Research Center for Health Biotechnology, College of Food Science and Biotechnology, Tianjin University of Science & Technology, Tianjin 300457, China; Beijing Advanced Innovation Center for Food Nutrition and Human Health, Beijing Technology and Business University (BTBU), Bingjin 100048, China
| | - Li-Li Ding
- State Key Laboratory of Food Nutrition and Safety, Key Laboratory of Food Nutrition and Safety, Ministry of Education, International Collaborative Research Center for Health Biotechnology, College of Food Science and Biotechnology, Tianjin University of Science & Technology, Tianjin 300457, China
| | - Zhi-Hui Pan
- Guangzhou Jammy Chai Sauce Workshop Co., Ltd., Guangzhou 510403, China
| | - De-Hua Kong
- Guangzhou Jammy Chai Sauce Workshop Co., Ltd., Guangzhou 510403, China
| | - Hadiatullah Hadiatullah
- State Key Laboratory of Food Nutrition and Safety, Key Laboratory of Food Nutrition and Safety, Ministry of Education, International Collaborative Research Center for Health Biotechnology, College of Food Science and Biotechnology, Tianjin University of Science & Technology, Tianjin 300457, China
| | - Zhen-Chuan Fan
- State Key Laboratory of Food Nutrition and Safety, Key Laboratory of Food Nutrition and Safety, Ministry of Education, International Collaborative Research Center for Health Biotechnology, College of Food Science and Biotechnology, Tianjin University of Science & Technology, Tianjin 300457, China.
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Inducible promoters and functional genomic approaches for the genetic engineering of filamentous fungi. Appl Microbiol Biotechnol 2018; 102:6357-6372. [PMID: 29860590 PMCID: PMC6061484 DOI: 10.1007/s00253-018-9115-1] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2018] [Revised: 05/17/2018] [Accepted: 05/18/2018] [Indexed: 12/15/2022]
Abstract
In industry, filamentous fungi have a prominent position as producers of economically relevant primary or secondary metabolites. Particularly, the advent of genetic engineering of filamentous fungi has led to a growing number of molecular tools to adopt filamentous fungi for biotechnical applications. Here, we summarize recent developments in fungal biology, where fungal host systems were genetically manipulated for optimal industrial applications. Firstly, available inducible promoter systems depending on carbon sources are mentioned together with various adaptations of the Tet-Off and Tet-On systems for use in different industrial fungal host systems. Subsequently, we summarize representative examples, where diverse expression systems were used for the production of heterologous products, including proteins from mammalian systems. In addition, the progressing usage of genomics and functional genomics data for strain improvement strategies are addressed, for the identification of biosynthesis genes and their related metabolic pathways. Functional genomic data are further used to decipher genomic differences between wild-type and high-production strains, in order to optimize endogenous metabolic pathways that lead to the synthesis of pharmaceutically relevant end products. Lastly, we discuss how molecular data sets can be used to modify products for optimized applications.
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Kamaruddin N, Storms R, Mahadi NM, Illias RM, Bakar FDA, Murad AMA. Reduction of Extracellular Proteases Increased Activity and Stability of Heterologous Protein in $${ Aspergillus}$$ A s p e r g i l l u s $${ niger}$$ n i g e r. ARABIAN JOURNAL FOR SCIENCE AND ENGINEERING 2017. [DOI: 10.1007/s13369-017-2914-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Sui YF, Ouyang LM, Chu J, Cao WQ, liang LF, Zhuang YP, Cheng S, Norrman H, Zhang SL, zhang GY. Global transcriptional response of Aspergillus niger in the process of glucoamylase fermentation. BIORESOUR BIOPROCESS 2017. [DOI: 10.1186/s40643-017-0160-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
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Schuetze T, Meyer V. Polycistronic gene expression in Aspergillus niger. Microb Cell Fact 2017; 16:162. [PMID: 28946884 PMCID: PMC5613464 DOI: 10.1186/s12934-017-0780-z] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2017] [Accepted: 09/20/2017] [Indexed: 12/12/2022] Open
Abstract
Background Genome mining approaches predict dozens of biosynthetic gene clusters in each of the filamentous fungal genomes sequenced so far. However, the majority of these gene clusters still remain cryptic because they are not expressed in their natural host. Simultaneous expression of all genes belonging to a biosynthetic pathway in a heterologous host is one approach to activate biosynthetic gene clusters and to screen the metabolites produced for bioactivities. Polycistronic expression of all pathway genes under control of a single and tunable promoter would be the method of choice, as this does not only simplify cloning procedures, but also offers control on timing and strength of expression. However, polycistronic gene expression is a feature not commonly found in eukaryotic host systems, such as Aspergillus niger. Results In this study, we tested the suitability of the viral P2A peptide for co-expression of three genes in A. niger. Two genes descend from Fusarium oxysporum and are essential to produce the secondary metabolite enniatin (esyn1, ekivR). The third gene (luc) encodes the reporter luciferase which was included to study position effects. Expression of the polycistronic gene cassette was put under control of the Tet-On system to ensure tunable gene expression in A. niger. In total, three polycistronic expression cassettes which differed in the position of luc were constructed and targeted to the pyrG locus in A. niger. This allowed direct comparison of the luciferase activity based on the position of the luciferase gene. Doxycycline-mediated induction of the Tet-On expression cassettes resulted in the production of one long polycistronic mRNA as proven by Northern analyses, and ensured comparable production of enniatin in all three strains. Notably, gene position within the polycistronic expression cassette matters, as, luciferase activity was lowest at position one and had a comparable activity at positions two and three. Conclusions The P2A peptide can be used to express at least three genes polycistronically in A. niger. This approach can now be applied to heterologously express entire secondary metabolite gene clusters polycistronically or to co-express any genes of interest in equimolar amounts. Electronic supplementary material The online version of this article (doi:10.1186/s12934-017-0780-z) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Tabea Schuetze
- Department of Applied Microbiology and Genetics, Technische Universität Berlin, Gustav-Meyer-Allee 25, 13355, Berlin, Germany.
| | - Vera Meyer
- Department of Applied Microbiology and Genetics, Technische Universität Berlin, Gustav-Meyer-Allee 25, 13355, Berlin, Germany
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Havlik D, Brandt U, Bohle K, Fleißner A. Establishment of Neurospora crassa as a host for heterologous protein production using a human antibody fragment as a model product. Microb Cell Fact 2017; 16:128. [PMID: 28743272 PMCID: PMC5526295 DOI: 10.1186/s12934-017-0734-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2017] [Accepted: 07/05/2017] [Indexed: 12/16/2022] Open
Abstract
Background Filamentous fungi are commonly used as production hosts for bulk enzymes in biotechnological applications. Their robust and quick growth combined with their ability to secrete large amounts of protein directly into the culture medium makes fungi appealing organisms for the generation of novel production systems. The red bread mold Neurospora crassa has long been established as a model system in basic research. It can be very easily genetically manipulated and a wealth of molecular tools and mutants are available. In addition, N. crassa is very fast growing and non-toxic. All of these features point to a high but so far untapped potential of this fungus for biotechnological applications. In this study, we used genetic engineering and bioprocess development in a design-build-test-cycle process to establish N. crassa as a production host for heterologous proteins. Results The human antibody fragment HT186-D11 was fused to a truncated version of the endogenous enzyme glucoamylase (GLA-1), which served as a carrier protein to achieve secretion into the culture medium. A modular expression cassette was constructed and tested under the control of different promoters. Protease activity was identified as a major limitation of the production strain, and the effects of different mutations causing protease deficiencies were compared. Furthermore, a parallel bioreactor system (1 L) was employed to develop and optimize a production process, including the comparison of different culture media and cultivation parameters. After successful optimization of the production strain and the cultivation conditions an exemplary scale up to a 10 L stirred tank reactor was performed. Conclusions The data of this study indicate that N. crassa is suited for the production and secretion of heterologous proteins. Controlling expression by the optimized promoter Pccg1nr in a fourfold protease deletion strain resulted in the successful secretion of the heterologous product with estimated yields of 3 mg/L of the fusion protein. The fungus could easily be cultivated in bioreactors and a first scale-up was successful. The system holds therefore much potential, warranting further efforts in optimization. Electronic supplementary material The online version of this article (doi:10.1186/s12934-017-0734-5) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- David Havlik
- Division of Pharmaceutical Biotechnology, Fraunhofer Institute for Toxicology and Experimental Medicine (ITEM), Inhoffenstr. 7, Braunschweig, 38124, Germany.,Institut für Genetik, Technische Universität Braunschweig, Spielmannstr. 7, 38106, Braunschweig, Germany.,Navigo Proteins GmbH, Heinrich-Damerow-Str. 1, 06120, Halle (Saale), Germany
| | - Ulrike Brandt
- Institut für Genetik, Technische Universität Braunschweig, Spielmannstr. 7, 38106, Braunschweig, Germany
| | - Kathrin Bohle
- Division of Pharmaceutical Biotechnology, Fraunhofer Institute for Toxicology and Experimental Medicine (ITEM), Inhoffenstr. 7, Braunschweig, 38124, Germany
| | - André Fleißner
- Institut für Genetik, Technische Universität Braunschweig, Spielmannstr. 7, 38106, Braunschweig, Germany.
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Reilly MC, Magnuson JK, Baker SE. Approaches to understanding protein hypersecretion in fungi. FUNGAL BIOL REV 2016. [DOI: 10.1016/j.fbr.2016.06.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Wanka F, Arentshorst M, Cairns TC, Jørgensen T, Ram AFJ, Meyer V. Highly active promoters and native secretion signals for protein production during extremely low growth rates in Aspergillus niger. Microb Cell Fact 2016; 15:145. [PMID: 27544686 PMCID: PMC4992228 DOI: 10.1186/s12934-016-0543-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2016] [Accepted: 08/08/2016] [Indexed: 01/06/2023] Open
Abstract
Background The filamentous ascomycete Aspergillus niger is used in many industrial processes for the production of enzymes and organic acids by batch and fed-batch cultivation. An alternative technique is continuous cultivation, which promises improved yield and optimized pipeline efficiency. Results In this work, we have used perfusion (retentostat) cultivation to validate two promoters that are suitable for A. niger continuous cultivation of industrially relevant products. Firstly, promoters of genes encoding either an antifungal protein (Panafp) or putative hydrophobin (PhfbD) were confirmed as active throughout retentostat culture by assessing mRNA and protein levels using a luciferase (mluc) reporter system. This demonstrated the anafp promoter mediates a high but temporally variable expression profile, whereas the hfbD promoter mediates a semi-constant, moderate-to-high protein expression during retentostat culture. In order to assess whether these promoters were suitable to produce heterologous proteins during retentostat cultivation, the secreted antifungal protein (AFP) from Aspergillus giganteus, which has many potential biotechnological applications, was expressed in A. niger during retentostat cultivation. Additionally, this assay was used to concomitantly validate that native secretion signals encoded in anafp and hfbD genes can be harnessed for secretion of heterologous proteins. Afp mRNA and protein abundance were comparable to luciferase measurements throughout retentostat cultivation, validating the use of Panafp and PhfbD for perfusion cultivation. Finally, a gene encoding the highly commercially relevant thermal hysteresis protein (THP) was expressed in this system, which did not yield detectable protein. Conclusion Both hfbD and anafp promoters are suitable for production of useful products in A. niger during perfusion cultivation. These findings provide a platform for further optimisations for high production of heterologous proteins with industrial relevance. Electronic supplementary material The online version of this article (doi:10.1186/s12934-016-0543-2) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Franziska Wanka
- Department Applied and Molecular Microbiology, Institute of Biotechnology, Berlin University of Technology, Gustav-Meyer-Allee 25, 13355, Berlin, Germany
| | - Mark Arentshorst
- Department Molecular Microbiology and Biotechnology, Institute of Biology Leiden, Leiden University, Sylviusweg 72, 2333 BE, Leiden, The Netherlands
| | - Timothy C Cairns
- Department Applied and Molecular Microbiology, Institute of Biotechnology, Berlin University of Technology, Gustav-Meyer-Allee 25, 13355, Berlin, Germany
| | - Thomas Jørgensen
- Protein Expression, Novo Nordisk, Novo Nordisk Park, 2760, Måløv, Denmark
| | - Arthur F J Ram
- Department Molecular Microbiology and Biotechnology, Institute of Biology Leiden, Leiden University, Sylviusweg 72, 2333 BE, Leiden, The Netherlands
| | - Vera Meyer
- Department Applied and Molecular Microbiology, Institute of Biotechnology, Berlin University of Technology, Gustav-Meyer-Allee 25, 13355, Berlin, Germany.
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RNA Sequencing-Based Genome Reannotation of the Dermatophyte Arthroderma benhamiae and Characterization of Its Secretome and Whole Gene Expression Profile during Infection. mSystems 2016; 1:mSystems00036-16. [PMID: 27822542 PMCID: PMC5069957 DOI: 10.1128/msystems.00036-16] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2016] [Accepted: 06/27/2016] [Indexed: 01/08/2023] Open
Abstract
Dermatophytoses (ringworm, jock itch, athlete’s foot, and nail infections) are the most common fungal infections, but their virulence mechanisms are poorly understood. Combining transcriptomic data obtained from growth under various culture conditions with data obtained during infection led to a significantly improved genome annotation. About 65% of the protein-encoding genes predicted with our protocol did not match the existing annotation for A. benhamiae. Comparing gene expression during infection on guinea pigs with keratin degradation in vitro, which is supposed to mimic the host environment, revealed the critical importance of using real in vivo conditions for investigating virulence mechanisms. The analysis of genes expressed in vivo, encoding cell surface and secreted proteins, particularly proteases, led to the identification of new allergen and virulence factor candidates. Dermatophytes are the most common agents of superficial mycoses in humans and animals. The aim of the present investigation was to systematically identify the extracellular, possibly secreted, proteins that are putative virulence factors and antigenic molecules of dermatophytes. A complete gene expression profile of Arthroderma benhamiae was obtained during infection of its natural host (guinea pig) using RNA sequencing (RNA-seq) technology. This profile was completed with those of the fungus cultivated in vitro in two media containing either keratin or soy meal protein as the sole source of nitrogen and in Sabouraud medium. More than 60% of transcripts deduced from RNA-seq data differ from those previously deposited for A. benhamiae. Using these RNA-seq data along with an automatic gene annotation procedure, followed by manual curation, we produced a new annotation of the A. benhamiae genome. This annotation comprised 7,405 coding sequences (CDSs), among which only 2,662 were identical to the currently available annotation, 383 were newly identified, and 15 secreted proteins were manually corrected. The expression profile of genes encoding proteins with a signal peptide in infected guinea pigs was found to be very different from that during in vitro growth when using keratin as the substrate. Especially, the sets of the 12 most highly expressed genes encoding proteases with a signal sequence had only the putative vacuolar aspartic protease gene PEP2 in common, during infection and in keratin medium. The most upregulated gene encoding a secreted protease during infection was that encoding subtilisin SUB6, which is a known major allergen in the related dermatophyte Trichophyton rubrum. IMPORTANCE Dermatophytoses (ringworm, jock itch, athlete’s foot, and nail infections) are the most common fungal infections, but their virulence mechanisms are poorly understood. Combining transcriptomic data obtained from growth under various culture conditions with data obtained during infection led to a significantly improved genome annotation. About 65% of the protein-encoding genes predicted with our protocol did not match the existing annotation for A. benhamiae. Comparing gene expression during infection on guinea pigs with keratin degradation in vitro, which is supposed to mimic the host environment, revealed the critical importance of using real in vivo conditions for investigating virulence mechanisms. The analysis of genes expressed in vivo, encoding cell surface and secreted proteins, particularly proteases, led to the identification of new allergen and virulence factor candidates.
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Burggraaf AM, Punt PJ, Ram AFJ. The unconventional secretion of PepN is independent of a functional autophagy machinery in the filamentous fungusAspergillus niger. FEMS Microbiol Lett 2016; 363:fnw152. [DOI: 10.1093/femsle/fnw152] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/02/2016] [Indexed: 12/12/2022] Open
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Burggraaf AM, Ram AFJ. Autophagy is dispensable to overcome ER stress in the filamentous fungus Aspergillus niger. Microbiologyopen 2016; 5:647-58. [PMID: 27027276 PMCID: PMC4985598 DOI: 10.1002/mbo3.359] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2015] [Revised: 02/25/2016] [Accepted: 03/08/2016] [Indexed: 02/06/2023] Open
Abstract
Secretory proteins are subjected to stringent quality control systems in the endoplasmic reticulum (ER) which include the targeting of misfolded proteins for proteasomal destruction via the ER‐associated degradation (ERAD) pathway. Since deletion of ERAD genes in the filamentous fungus Aspergillus niger had hardly any effect on growth, this study investigates whether autophagy might function as an alternative process to eliminate misfolded proteins from the ER. We generated A. niger double mutants by deleting genes essential for ERAD (derA) and autophagy (atg1 or atg8), and assessed their growth both under normal and ER stress conditions. Sensitivity toward ER stress was examined by treatment with dithiothreitol (DTT) and by expressing a mutant form of glucoamylase (mtGlaA::GFP) in which disulfide bond sites in GlaA were mutated. Misfolding of mtGlaA::GFP was confirmed, as mtGlaA::GFP accumulated in the ER. Expression of mtGlaA::GFP in ERAD and autophagy mutants resulted in a twofold higher accumulation in ΔderA and ΔderAΔatg1 strains compared to Δatg1 and wild type. As ΔderAΔatg1 mutants did not show increased sensitivity toward DTT, not even when mtGlaA::GFP was expressed, the results indicate that autophagy does not act as an alternative pathway in addition to ERAD for removing misfolded proteins from the ER in A. niger.
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Affiliation(s)
- Anne-Marie Burggraaf
- Molecular Microbiology and Biotechnology, Institute of Biology Leiden, Leiden University, Sylviusweg 72, 2333 BE, Leiden, The Netherlands
| | - Arthur F J Ram
- Molecular Microbiology and Biotechnology, Institute of Biology Leiden, Leiden University, Sylviusweg 72, 2333 BE, Leiden, The Netherlands
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Li N, Kunitake E, Endo Y, Aoyama M, Kanamaru K, Kimura M, Kato M, Kobayashi T. Involvement of an SRF-MADS protein McmA in regulation of extracellular enzyme production and asexual/sexual development in Aspergillus nidulans. Biosci Biotechnol Biochem 2016; 80:1820-8. [PMID: 26967516 DOI: 10.1080/09168451.2016.1146074] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
SRF-MADS proteins are transcription factors conserved among eukaryotes that regulate a variety of cellular functions; however, their physiological roles are still not well understood in filamentous fungi. Effects of a mutation in mcmA gene that encodes the sole SRF-MADS protein in the fungus Aspergillus nidulans were examined by RNA sequencing. Sequencing data revealed that expression levels of cellulase genes were significantly decreased by the mutation as reported previously. However, expression levels of various hemicellulolytic enzyme genes, several extracellular protease genes, the nosA and rosA genes involved in sexual development, and AN4394 encoding an ortholog of EcdR involved in Aspergillus oryzae conidiation, were also significantly decreased by the mutation. As expected from the RNA sequencing data, the mcmA mutant had reduced protease production, cleistothecial development, and conidiation. This is the first report describing the involvement of SRF-MADS proteins in protease production in fungi, and asexual and sexual development in Aspergillus.
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Affiliation(s)
| | - Emi Kunitake
- a Department of Biological Mechanisms and Functions , Graduate School of Bioagricultural Sciences, Nagoya University , Nagoya , Japan
| | - Yoshikazu Endo
- a Department of Biological Mechanisms and Functions , Graduate School of Bioagricultural Sciences, Nagoya University , Nagoya , Japan
| | - Miki Aoyama
- a Department of Biological Mechanisms and Functions , Graduate School of Bioagricultural Sciences, Nagoya University , Nagoya , Japan
| | - Kyoko Kanamaru
- a Department of Biological Mechanisms and Functions , Graduate School of Bioagricultural Sciences, Nagoya University , Nagoya , Japan
| | - Makoto Kimura
- a Department of Biological Mechanisms and Functions , Graduate School of Bioagricultural Sciences, Nagoya University , Nagoya , Japan
| | - Masashi Kato
- a Department of Biological Mechanisms and Functions , Graduate School of Bioagricultural Sciences, Nagoya University , Nagoya , Japan
| | - Tetsuo Kobayashi
- a Department of Biological Mechanisms and Functions , Graduate School of Bioagricultural Sciences, Nagoya University , Nagoya , Japan
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Gómez S, López-Estepa M, Fernández FJ, Suárez T, Vega MC. Alternative Eukaryotic Expression Systems for the Production of Proteins and Protein Complexes. ADVANCED TECHNOLOGIES FOR PROTEIN COMPLEX PRODUCTION AND CHARACTERIZATION 2016; 896:167-84. [DOI: 10.1007/978-3-319-27216-0_11] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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Gene Expression in Filamentous Fungi: Advantages and Disadvantages Compared to Other Systems. Fungal Biol 2016. [DOI: 10.1007/978-3-319-27951-0_8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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