DOCSLIB.ORG

Genetic Modification of Enzymes and Metabolic Pathways for the Improvement of Fatty Acid Synthesis in the Yeast Saccharomyces Cerevisiae

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Genetic Modification of Enzymes and Metabolic Pathways for the Improvement of Fatty Acid Synthesis in the Yeast Saccharomyces Cerevisiae Genetic modification of enzymes and metabolic pathways for the improvement of fatty acid synthesis in the yeast Saccharomyces cerevisiae Dissertation zur Erlangung des Doktorgrades der Naturwissenschaften vorgelegt beim Fachbereich Biowissenschaften der Goethe-Universität in Frankfurt am Main von Renata Pavlović aus Kakanj, Bosnien-Herzegowina Frankfurt am Main 2016 (D 30) vom Fachbereich Biowissenschaften der Goethe-Universität Frankfurt als Dissertation angenommen. Dekanin: Prof. Dr. Meike Piepenbring Gutachter: Prof. Dr. Eckhard Boles Prof. Dr. Martin Grininger Datum der Disputation: 28. Februar 2017 The mystery of human existence lies not in just staying alive, but in finding something to live for. Fyodor Dostoyevsky Table of contents Summary __________________________________________________________________ 1 1. Introduction ___________________________________________________________ 3 Fatty acid biosynthesis and degradation ________________________________________ 4 1.1.2 Fatty acid biosynthesis in S. cerevisiae ______________________________________________________ 4 1.1.3 Elongation and synthesis of unsaturated fatty acids ___________________________________________ 6 1.1.4 Fatty acids as energy storage ______________________________________________________________ 8 1.1.5 Degradation and export of fatty acids _______________________________________________________ 9 Metabolic engineering ______________________________________________________ 10 1.2.1 Fermentation medium __________________________________________________________________ 10 1.2.2 Oleaginous microorganisms ______________________________________________________________ 10 1.2.3 Pathway optimization___________________________________________________________________ 12 Aim of this work ___________________________________________________________ 16 2. Materials and Methods _________________________________________________ 17 Medium, microorganisms and cultivation ______________________________________ 17 2.1.1 Medium ______________________________________________________________________________ 17 2.1.2 Microorganisms and their cultivation ______________________________________________________ 18 Plasmids _________________________________________________________________ 19 Oligonucleotides __________________________________________________________ 24 Materials, chemicals and equipment __________________________________________ 24 Molecular biological methods ________________________________________________ 26 2.5.1 Isolation of plasmid DNA from E. coli ______________________________________________________ 26 2.5.2 Isolation of plasmid and genomic DNA from S. cerevisiae ______________________________________ 26 2.5.3 Determination of DNA concentration ______________________________________________________ 27 2.5.4 Digestion of DNA with restriction endonucleases (restriction digestion) __________________________ 27 2.5.5 Polymerase chain reaction (PCR) __________________________________________________________ 28 2.5.6 Agarose gel-electrophoresis for DNA separation _____________________________________________ 28 2.5.7 DNA-purification and DNA-extraction form agarose gels _______________________________________ 28 2.5.8 DNA sequencing _______________________________________________________________________ 28 Genetic methods __________________________________________________________ 29 2.6.1 Transformation of E. coli ________________________________________________________________ 29 2.6.2 Transformation of S. cerevisiae ___________________________________________________________ 29 2.6.3 Codon optimization of genes _____________________________________________________________ 30 2.6.4 Plasmid construction by recombinational cloning ____________________________________________ 30 2.6.5 Plasmid construction by Gibson assembly __________________________________________________ 30 I Table of contents 2.6.6 Genomic gene deletion by Delitto Perfetto__________________________________________________ 31 2.6.7 Genomic gene deletion by CRISPR/Cas9 ____________________________________________________ 31 Methods for cell cultivation and fermentation experiments ________________________ 32 2.7.1 Spectrophotometrical determination of cell density __________________________________________ 32 2.7.2 Glycerol stock cultures __________________________________________________________________ 32 2.7.3 Serial dilution spot assay ________________________________________________________________ 33 2.7.4 Aerobic batch fermentations _____________________________________________________________ 33 2.7.5 Aerobic batch fermentations with ion exchanger _____________________________________________ 33 2.7.6 Lyophilisation of cell pellets and determination of cell dry weight _______________________________ 33 Metabolite analysis by HPLC _________________________________________________ 34 Fatty acid analysis _________________________________________________________ 34 2.9.1 Extraction of lipids from culture medium ___________________________________________________ 34 2.9.2 Extraction of lipids from dry cell pellet _____________________________________________________ 34 2.9.3 Preparation of fatty acid methyl esters _____________________________________________________ 35 2.9.4 Determination of fatty acid methyl esters by GC _____________________________________________ 35 2.9.5 Preparation of fatty acids with DMDS ______________________________________________________ 35 2.9.6 Fatty acid analysis by GC-MS _____________________________________________________________ 36 2.9.7 Thin layer chromatography (TLC) __________________________________________________________ 36 In Silico Methods & Software ________________________________________________ 36 3. Results _______________________________________________________________ 37 Desaturases ______________________________________________________________ 37 3.1.1 Screening for desaturases with terminal desaturase activity ____________________________________ 37 3.1.2 Site directed mutagenesis of Δ9 desaturase Ole1p ___________________________________________ 44 Improving fatty acid synthesis _______________________________________________ 48 3.2.1 Optimization of acetyl-CoA synthesis ______________________________________________________ 48 3.2.2 Increasing fatty acid content by DGA1 and TGL3 expression ____________________________________ 50 Medium chain fatty acid synthesis ____________________________________________ 53 3.3.1 Effect of FAS mutations on fatty acid synthesis ______________________________________________ 53 3.3.2 Effect of culture medium on fatty acid synthesis _____________________________________________ 60 3.3.3 Effect of promoter exchange on fatty acid synthesis __________________________________________ 62 3.3.4 Optimization of MCFA synthesis by metabolic engineering _____________________________________ 67 3.3.4.1 Deletion of acyl-CoA synthetase Faa2p ___________________________________________________ 67 3.3.4.2. Degradation of triacylglycerol __________________________________________________________ 69 3.3.5 Extraction of MCFA from medium with ion exchanger _________________________________________ 72 3.3.6. Analysis of putative hydrolases for MCFA production _________________________________________ 76 3.3.6.1 Identification of putative hydrolases _____________________________________________________ 76 3.3.6.2 Effect of EEB1, EHT1 and MGL2 deletion __________________________________________________ 77 II Table of contents 4. Discussion ____________________________________________________________ 82 Desaturases ______________________________________________________________ 82 4.1.1 Characterization of fungi desaturases ______________________________________________________ 83 4.1.2 Site directed mutagenesis in Ole1p ________________________________________________________ 85 Improving fatty acid synthesis in general _______________________________________ 86 4.2.1 Implementation of co-substrate and metabolite synthesis _____________________________________ 86 4.2.2 Deletion of fatty acyl-CoA synthetases _____________________________________________________ 88 Medium chain fatty acids ___________________________________________________ 89 4.3.1 Selective production of MCFA by reprograming of the FAS _____________________________________ 89 4.3.2 Culture medium composition ____________________________________________________________ 93 4.3.3 Change expression pattern of mutated FAS _________________________________________________ 95 4.3.4 Best approach for optimal yield of MCFA ___________________________________________________ 97 4.3.5 Improved metabolic fluxes towards MCFA synthesis __________________________________________ 98 4.3.6 Three acyl-CoA thioesterase with different substrate spectrum ________________________________ 100 4.3.7 Continuous product removal with a ion exchange resins ______________________________________ 102 Outlook _________________________________________________________________ 102 5. Zusammenfassung ____________________________________________________ 104 6. References ___________________________________________________________ 109 7. Appendices __________________________________________________________ 128 I. Abbreviations ____________________________________________________________ 128 II. DNA oligonucleotides ______________________________________________________ 131 III. Supplemental figures and tables _____________________________________________ 140 IV. Acknowledgements _______________________________________________________
Load more

Recommended publications
  • Molecular Dynamics Simulation of Protein Biosurfactants
    colloids and interfaces Review Molecular Dynamics Simulation of Protein Biosurfactants David L. Cheung * and Suman Samantray School of Chemistry, National University of Ireland Galway, University Road, H91 TK33 Galway, Ireland; [email protected] * Correspondence: [email protected]; Tel.: +353-91-492450 Received: 19 August 2018; Accepted: 6 September 2018; Published: 8 September 2018 Abstract: Surfaces and interfaces are ubiquitous in nature and are involved in many biological processes. Due to this, natural organisms have evolved a number of methods to control interfacial and surface properties. Many of these methods involve the use of specialised protein biosurfactants, which due to the competing demands of high surface activity, biocompatibility, and low solution aggregation may take structures that differ from the traditional head–tail structure of small molecule surfactants. As well as their biological functions, these proteins have also attracted interest for industrial applications, in areas including food technology, surface modification, and drug delivery. To understand the biological functions and technological applications of protein biosurfactants, it is necessary to have a molecular level description of their behaviour, in particular at surfaces and interfaces, for which molecular simulation is well suited to investigate. In this review, we will give an overview of simulation studies of a number of examples of protein biosurfactants (hydrophobins, surfactin, and ranaspumin). We will also outline some of the key challenges and future directions for molecular simulation in the investigation of protein biosurfactants and how this can help guide future developments. Keywords: biosurfactants; molecular dynamics simulation; protein structure; interfacial science 1. Introduction In order to control the properties of surfaces and interfaces, many organisms have evolved specialised surface active biomolecules, such as protein or peptide biosurfactants, which fulfill a number of key biological functions [1,2].
    [Show full text]
  • HYD3, a Conidial Hydrophobin of the Fungal Entomopathogen Metarhizium
    bioRxiv preprint doi: https://doi.org/10.1101/2020.06.13.149757; this version posted June 15, 2020. The copyright holder for this preprint (which was not certified by peer review) is the author/funder. All rights reserved. No reuse allowed without permission. 1 HYD3, a conidial hydrophobin of the fungal entomopathogen Metarhizium 2 acridum induces the immunity of its specialist host locust 3 4 Zeyuan Jiang1, Petros Ligoxygakis2, Yuxian Xia1* 5 1Genetic Engineering Research Center, School of Life Sciences, Chongqing 6 University, Chongqing 400045, People’s Republic of China. 2Department of 7 Biochemistry, South Parks Rd, University of Oxford, Oxford OX1 3QU United 8 Kingdom 9 *Corresponding author: [email protected] 10 Abstract: Conidial hydrophobins in fungal pathogens of plants1,2, insects3,4, and 11 humans5,6 are required for fungal attachment and are associated with high virulence. 12 They are believed to contribute to the pathogenesis of infection by preventing immune 13 recognition5,6. Here, we refute this generalisation offering a more nuanced analysis. 14 We show that MacHYD3, a hydrophobin located on the conidial surface of the 15 specialist entomopathogenic fungus Metarhizium acridum, activates specifically the 16 humoral and cellular immunity of its own host insect, Locusta migratoria 17 manilensis (Meyen) but not that of other non-host insects. When topically applied to 18 the cuticle, purified MacHYD3 improved the resistance of locusts to both specialist 19 and generalist fungal pathogens but had no effect on the fungal resistance of other 20 insects, including Spodoptera frugiperda and Galleria mellonella. Hydrophobins 21 extracted from the generalist fungal pathogens M.
    [Show full text]
  • Botrytis Cinerea Andreas Mosbach1, Michaela Leroch1, Kurt W Mendgen2, Matthias Hahn1*
    Mosbach et al. BMC Microbiology 2011, 11:10 http://www.biomedcentral.com/1471-2180/11/10 RESEARCHARTICLE Open Access Lack of evidence for a role of hydrophobins in conferring surface hydrophobicity to conidia and hyphae of Botrytis cinerea Andreas Mosbach1, Michaela Leroch1, Kurt W Mendgen2, Matthias Hahn1* Abstract Background: Hydrophobins are small, cysteine rich, surface active proteins secreted by filamentous fungi, forming hydrophobic layers on the walls of aerial mycelia and spores. Hydrophobin mutants in a variety of fungi have been described to show ‘easily wettable’ phenotypes, indicating that hydrophobins play a general role in conferring surface hydrophobicity to aerial hyphae and spores. Results: In the genome of the grey mould fungus Botrytis cinerea, genes encoding three hydrophobins and six hydrophobin-like proteins were identified. Expression analyses revealed low or no expression of these genes in conidia, while some of them showed increased or specific expression in other stages, such as sclerotia or fruiting bodies. Bhp1 belongs to the class I hydrophobins, whereas Bhp2 and Bhp3 are members of hydrophobin class II. Single, double and triple hydrophobin knock-out mutants were constructed by consecutively deleting bhp1, bhp2 and bhp3. In addition, a mutant in the hydrophobin-like gene bhl1 was generated. The mutants were tested for germination and growth under different conditions, formation of sclerotia, ability to penetrate and infect host tissue, and for spore and mycelium surface properties. Surprisingly, none of the B. cinerea hydrophobin mutants showed obvious phenotypic defects in any of these characters. Scanning electron microscopy of the hydrophobic conidial surfaces did not reveal evidence for the presence of typical hydrophobin ‘rodlet’ layers.
    [Show full text]
  • Comparison of DNA Extraction Methodologies Used for Assessing Fungal Diversity Via ITS Sequencing
    HHS Public Access Author manuscript Author Manuscript Author ManuscriptJ Environ Author Manuscript Monit. Author Author Manuscript manuscript; available in PMC 2015 December 21. Published in final edited form as: J Environ Monit. 2012 March ; 14(3): 766–774. doi:10.1039/c2em10779a. Comparison of DNA extraction methodologies used for assessing fungal diversity via ITS sequencing William R. Rittenoura, Ju-Hyeong Parkb, Jean M. Cox-Ganserb, Donald H. Beezholda, and Brett J. Greena aAllergy and Clinical Immunology Branch, Health Effects Laboratory Division, National Institute for Occupational Safety and Health, 1095 Willowdale Rd., Morgantown, West Virginia, USA. [email protected]; Tel: +1 304-285-5721 ext 7 bField Studies Branch, Division of Respiratory Disease Studies, National Institute for Occupational Safety and Health, Morgantown, West Virginia, USA Abstract Traditional methods of assessing fungal exposure have been confounded by a number of limiting variables. The recent utilization of molecular methods such as internal transcribed spacer (ITS) sequencing of ribosomal RNA genes has provided improved insight into the diversity of fungal bioaerosols in indoor, outdoor and occupational environments. However, ITS analyses may also be confounded by a number of methodological limitations. In this study, we have optimized this technology for use in occupational or environmental studies. Three commonly used DNA extraction methodologies (UltraClean Soil kit, High Pure PCR Template kit, and EluQuik/DNeasy kit) were compared in terms of sensitivity and susceptibility to PCR inhibitors in dust for three common fungal bioaerosols, Aspergillus versicolor, Rhizopus microsporus and Wallemia sebi. Environmental dust samples were then studied using each extraction methodology and results were compared to viable culture data.
    [Show full text]
  • Comparative Analysis of Surface Coating Properties of Five
    www.nature.com/scientificreports OPEN Comparative analysis of surface coating properties of fve hydrophobins from Aspergillus Received: 10 May 2018 Accepted: 18 July 2018 nidulans and Trichoderma reseei Published: xx xx xxxx Lex Winandy1, Felix Hilpert2, Oleksandra Schlebusch1 & Reinhard Fischer1 Fungal hydrophobins are small amphiphilic proteins that self-assemble into monolayers on hydrophobic:hydrophilic interfaces and can be used for surface coatings. Because e.g. Aspergillus nidulans contains six diferent hydrophobins, it is likely that they have diferent properties and are used for diferent “applications” in the fungus. We established a method for recombinant production of diferent class hydrophobins in Escherichia coli. We produced DewA, DewC, DewD, DewE from A. nidulans and HFBI from Trichoderma reesei and compared surface coating properties of these hydrophobins. All tested proteins formed coatings on glass, strongly increasing the hydrophobicity of the surface, and showed emulsion-stabilizing properties. But whereas the typical class I hydrophobin DewA formed the most stable coating on glass, the intermediate class hydrophobins DewE and DewD were more efective in stabilization of oil:water emulsions. This work gives insights into correlations between structural characteristics of hydrophobins and their behaviour as surface binding agents. It could help with the clarifcation of their biological functions and lead to novel biotechnological applications. Hydrophobins are small amphiphilic proteins that self-assemble into monolayers on hydrophilic and hydropho- bic surfaces and change their properties1–3. Fungi secrete these proteins to reduce surface tension and support hyphae growth or to increase the hydrophobicity of conidiospores, aerial hyphae and fruiting bodies2,4,5. Hydrophobins are cysteine rich proteins that are characterized by four intramolecular disulfde bridges6.
    [Show full text]
  • Genome and Transcriptome Sequencing of the Halophilic Fungus Wallemia Ichthyophaga: Haloadaptations Present and Absent Zajc Et Al
    Genome and transcriptome sequencing of the halophilic fungus Wallemia ichthyophaga: haloadaptations present and absent Zajc et al. Zajc et al. BMC Genomics 2013, 14:617 http://www.biomedcentral.com/1471-2164/14/617 Zajc et al. BMC Genomics 2013, 14:617 http://www.biomedcentral.com/1471-2164/14/617 RESEARCH ARTICLE Open Access Genome and transcriptome sequencing of the halophilic fungus Wallemia ichthyophaga: haloadaptations present and absent Janja Zajc1†, Yongfeng Liu2†, Wenkui Dai2, Zhenyu Yang2, Jingzhi Hu2, Cene Gostinčar1*† and Nina Gunde-Cimerman1,3† Abstract Background: The basidomycete Wallemia ichthyophaga from the phylogenetically distinct class Wallemiomycetes is the most halophilic fungus known to date. It requires at least 10% NaCl and thrives in saturated salt solution. To investigate the genomic basis of this exceptional phenotype, we obtained a de-novo genome sequence of the species type-strain and analysed its transcriptomic response to conditions close to the limits of its lower and upper salinity range. Results: The unusually compact genome is 9.6 Mb large and contains 1.67% repetitive sequences. Only 4884 predicted protein coding genes cover almost three quarters of the sequence. Of 639 differentially expressed genes, two thirds are more expressed at lower salinity. Phylogenomic analysis based on the largest dataset used to date (whole proteomes) positions Wallemiomycetes as a 250-million-year-old sister group of Agaricomycotina. Contrary to the closely related species Wallemia sebi, W. ichthyophaga appears to have lost the ability for sexual reproduction. Several protein families are significantly expanded or contracted in the genome. Among these, there are the P-type ATPase cation transporters, but not the sodium/ hydrogen exchanger family.
    [Show full text]
  • Role of Fusarium Graminearum Cerato-Platanin and Hydrophobin Proteins in Fungal Growth and Plant Infection
    Head Office: University of Padova Department of Agronomy, Food, Natural resources, Animals and Environment - DAFNAE Department of Land, Environment, Agriculture and Forestry - TeSAF _____________________________________________________________________________________ Ph.D. COURSE IN CROP SCIENCE XXX CYCLE ROLE OF FUSARIUM GRAMINEARUM CERATO-PLATANIN AND HYDROPHOBIN PROTEINS IN FUNGAL GROWTH AND PLANT INFECTION Coordinator: Ch.mo Prof. Sergio Casella Supervisor: Ch.mo Prof. Luca Sella Co-Supervisor: Ch.mo Prof. Francesco Favaron Ph.D. student: Alessandra Quarantin Declaration I hereby declare that this submission is my own work and that, to the best of my knowledge and belief, it contains no materials previously published or written by another person nor material which to a substantial extent has been accepted for the award of any other degree or diploma of the University or other institute of higher learning, except where due acknowledgment has been made in the text. A copy of the thesis will be available at http://paduaresearch.cab.unipd.it/dottorato/ Index Summary 1 Preface 3 Chapter I 5 Involvement of the Fusarium graminearum cerato-platanin proteins in fungal growth and plant infection Abstract 7 1.1. Introduction 9 1.2. Materials and methods 13 1.2.1. Sequences analysis and primer design 13 1.2.2. Fungal strains and culture conditions 13 1.2.3. Construction of the gene replacement vectors and fungal transformation-mediated gene disruption 14 1.2.4. Southern blot analysis 17 1.2.5. Plant growth and infection 17 1.2.6. Inoculation of wheat flower leaves 18 1.2.7. RNA extraction and Reverse Transcription (RT) 18 1.2.8.
    [Show full text]
  • Molecular Tools for Detection and Identification Of
    Journal of Fungi Review Molecular Tools for Detection and Identification of Paracoccidioides Species: Current Status and Future Perspectives Breno Gonçalves Pinheiro 1 , Rosane Christine Hahn 2,3, Zoilo Pires de Camargo 1,4 and Anderson Messias Rodrigues 1,* 1 Laboratory of Emerging Fungal Pathogens, Department of Microbiology, Immunology, and Parasitology, Discipline of Cellular Biology, Federal University of São Paulo (UNIFESP), São Paulo 04023062, Brazil; [email protected] (B.G.P.); [email protected] (Z.P.d.C.) 2 Laboratory of Mycology/Research, Faculty of Medicine, Federal University of Mato Grosso, Cuiabá, Mato Grosso 78060900, Brazil; [email protected] 3 Federal University of Mato Grosso, Júlio Muller University Hospital, Mato Grosso 78048902, Brazil 4 Department of Medicine, Discipline of infectious Diseases, Federal University of São Paulo (UNIFESP), São Paulo 04023062, Brazil * Correspondence: [email protected]; Tel.: +55-1155764551 (ext. 1540) Received: 13 October 2020; Accepted: 5 November 2020; Published: 18 November 2020 Abstract: Paracoccidioidomycosis (PCM) is a mycotic disease caused by the Paracoccidioides species, a group of thermally dimorphic fungi that grow in mycelial form at 25 ◦C and as budding yeasts when cultured at 37 ◦C or when parasitizing the host tissues. PCM occurs in a large area of Latin America, and the most critical regions of endemicity are in Brazil, Colombia, and Venezuela. The clinical diagnosis of PCM needs to be confirmed through laboratory tests. Although classical laboratory techniques provide valuable information due to the presence of pathognomonic forms of Paracoccidioides spp., nucleic acid-based diagnostics gradually are replacing or complementing culture-based, biochemical, and immunological assays in routine microbiology laboratory practice.
    [Show full text]
  • Soluble Expression and Efficient Purification of Recombinant Class I
    International Journal of Molecular Sciences Article Soluble Expression and Efficient Purification of Recombinant Class I Hydrophobin DewA Sang-Oh Ahn 1,†, Ho-Dong Lim 2,†, Sung-Hwan You 3, Dae-Eun Cheong 1 and Geun-Joong Kim 1,* 1 Department of Biological Sciences, College of Natural Sciences, Chonnam National University, Yongbong-ro, Buk-gu, Gwangju 61186, Korea; [email protected] (S.-O.A.); [email protected] (D.-E.C.) 2 Center for Industrialization of Agricultural and Livestock Microorganisms, 241 Cheomdangwahak-ro, Jeongeup-si 56212, Jeollabuk-do, Korea; [email protected] 3 Biomedical Research Center, Chonnam National University, Convergence Science Building (M2), Suite 301-1 264, Seoyang-ro, Hwasun-eup, Hwasun-gun 58128, Jeollanam-do, Korea; [email protected] * Correspondence: [email protected]; Tel.: +82-62-530-3403 † These authors contributed equally to this work. Abstract: Hydrophobins are small proteins (<20 kDa) with an amphipathic tertiary structure that are secreted by various filamentous fungi. Their amphipathic properties provide surfactant-like activity, leading to the formation of robust amphipathic layers at hydrophilic–hydrophobic interfaces, which make them useful for a wide variety of industrial fields spanning protein immobilization to surface functionalization. However, the industrial use of recombinant hydrophobins has been hampered due to low yield from inclusion bodies owing to the complicated process, including an auxiliary refolding step. Herein, we report the soluble expression of a recombinant class I hydrophobin DewA originating from Aspergillus nidulans, and its efficient purification from recombinant Escherichia coli. Soluble expression of the recombinant hydrophobin DewA was achieved by a tagging strategy using Citation: Ahn, S.-O.; Lim, H.-D.; a systematically designed expression tag (ramp tag) that was fused to the N-terminus of DewA You, S.-H.; Cheong, D.-E.; Kim, G.-J.
    [Show full text]
  • The Genus Wallemia—From Contamination of Food to Health Threat
    microorganisms Review The Genus Wallemia—From Contamination of Food to Health Threat Janja Zajc 1,2 and Nina Gunde-Cimerman 2,* 1 National Institute of Biology, Veˇcnapot 111, SI-1000 Ljubljana, Slovenia; [email protected] 2 Biology Department, Biotechnical Faculty, University of Ljubljana, Jamnikarjeva 101, SI-1000 Ljubljana, Slovenia * Correspondence: [email protected]; Tel: +386-1-3203400 Received: 11 April 2018; Accepted: 18 May 2018; Published: 21 May 2018 Abstract: The fungal genus Wallemia of the order Wallemiales (Wallemiomycotina, Basidiomycota) comprises the most xerotolerant, xerophilic and also halophilic species worldwide. Wallemia spp. are found in various osmotically challenged environments, such as dry, salted, or highly sugared foods, dry feed, hypersaline waters of solar salterns, salt crystals, indoor and outdoor air, and agriculture aerosols. Recently, eight species were recognized for the genus Wallemia, among which four are commonly associated with foods: W. sebi, W. mellicola, W. muriae and W. ichthyophaga. To date, only strains of W. sebi, W. mellicola and W. muriae have been reported to be related to human health problems, as either allergological conditions (e.g., farmer’s lung disease) or rare subcutaneous/cutaneous infections. Therefore, this allergological and infective potential, together with the toxins that the majority of Wallemia spp. produce even under saline conditions, defines these fungi as filamentous food-borne pathogenic fungi. Keywords: Wallemia; food; air; pathogen; xerophile; halophile; mycotoxin; farmer’s lung disease; subcutaneous infection 1. Introduction Low availability of water is one of the most life-limiting factors, and only specially adapted organisms can cope with such stress in their environment.
    [Show full text]
  • Detection and Characterisation of Fusarium Hydrophobins Inducing Gushing in Beer Tuija Sarlin
    IENCE C • •S T S E N C O H I N S O I V Dissertation L • O S G T 13 Y H • R G I E L S H E G A I R H C H Detection and characterisation of Fusarium hydrophobins inducing gushing in beer Tuija Sarlin VTT SCIENCE 13 Detection and characterisation of F hydrophobins inducing gushing in beer Tuija Sarlin D sertat D S T t ent it iss S Cmic T fo xaminati t Aditoriu Kmpp (K2) t At Usit S C T (E, F) t 21st Sember, 2012, 12 . ISBN 978-951-38-7473-5 (soft back ed.) ISSN 2242-119X (soft back ed.) ISBN 978-951-38-7474-2 (URL: http://www.vtt.fi/publications/index.jsp) ISSN 2242-1203 (URL: http://www.vtt.fi/publications/index.jsp) Copyright © VTT 2012 JULKAISIJA – UTGIVARE – PUBLISHER VTT PL 1000 (Tekniikantie 4 A, Espoo) 02044 VTT Puh. 020 722 111, faksi 020 722 7001 VTT PB 1000 (Teknikvägen 4 A, Esbo) FI-02044 VTT Tfn +358 20 722 111, telefax +358 20 722 7001 VTT Technical Research Centre of Finland P.O. Box 1000 (Tekniikantie 4 A, Espoo) FI-02044 VTT, Finland Tel. +358 20 722 111, fax + 358 20 722 7001 Technical editing Maini Manninen Kopijyvä Oy, Kuopio 2012 Detection and characterisation of Fusarium hydrophobins inducing gushing in beer [Oluen ylikuohuntaa aiheuttavien Fusarium-hydrofobiinien osoittaminen ja karakterisointi]. Tuija Sarlin. Espoo 2012. VTT Science 13. 82 p. + app. 55 p. Abstract Gushing is a phenomenon in which beer spontaneously, without agitation, vigorously foams out from its container immediately on opening.
    [Show full text]
  • Fungi Are Among the Most Common Foreign Aerobiological Particles That We Inhale
    Chapter 1∗ 1. Introduction Fungi are among the most common foreign aerobiological particles that we inhale. Personal exposure to airborne microorganisms, particularly fungi both in indoor, outdoor, residential and occupational environments, is widely recognized as exacerbating agents of non-infectious respiratory diseases such as allergic rhinitis, asthma, bronchitis, organic dust toxic syndrome and hypersensitivity pneumonitis. However, the role of fungi in mediating allergic reactions remains unclear. Although many species are known to produce allergens inducing an Immunoglobulin E (IgE) and IgG response, the importance of many other additional species remains unrecognised. This is partly because of the vast number of fungi that occur naturally and the diversity of allergens within different species, which is further confounded by the poor quality of commercial extracts available for diagnosis and the methods of analysis used to quantify airborne counts. In addition, the interaction of fungi with the airways is complex and involves a number of innate and acquired mechanisms, including allergic responses. This introduction will discuss the current understanding of allergy, the biology of fungi, the nature and location where people may come into contact with fungal allergens and review the methods available to measure exposure to airborne fungi and diagnose fungal allergic sensitisation. 1.1 Respiratory allergy – a brief history of the problem The first documented report of an allergic reaction occurred to King Menes of Egypt around 2, 600 B.C., who supposedly died from anaphylaxis following a wasp sting. ∗ Chapter 1, Section 1.6 was published as “Measuring environmental fungal exposure” in Medical Mycology in 2005. 1 Other reports from ancient history include, Britannicus, the son of the Roman emperor Claudius, who was described to develop swelling around his eyes following horse riding and King Richard III of England, who was reported to get urticaria from strawberries (Cohen and Evans, 1991).
    [Show full text]