DOCSLIB.ORG

Mycology: Unravelling the Riddle of the Filamentous Fungi

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Mycology: Unravelling the Riddle of the Filamentous Fungi Microbiology The picture shows different color mutants of Aspergillus nidulans. Wild type forms green spores which cover almost the entire colony. It is easy to generate mutants in which pigment biosynthesis is blocked at certain stages and thus a different pigment variant (yellow) or no pigments (white) are produced. Mutants are a great starting point for a molecular analysis. This approach has been used to study many cellular processes and made A. nidulans a model organism for lower eukaryotes and beyond. The diameter of a colony is about 1 cm. less well known is that they play a vital role, not only in generating nutrients, but also in plant nutrient uptake: every metre of plant root in the soil is associated with roughly a kilometre of symbiotic fungal hyphae, known as ‘mycorrhiza’, which take up nutrients and pass them to the plant. Filamentous fungi are important pathogens of crop plants, and in a few cases cause serious human disease, particularly in the immunocompromised. They have also been harnessed for biotechnological uses, including crucially in the production of antibiotics such With the help of the jellyfish green fluorescent protein (GFP) researchers visualised the microtubule as penicillin, other medicines, citric acid, cytoskeleton in Aspergillus nidulans. Round spores and foods such as soy sauce and cheese. To produced long hyphae, and microtubules are visible as long filaments in the cells. They serve as tracks scientists, fungi are also important due to the for intracellular traffic. (picture taken by Minoas similarity of their cells to human cells, making Evangelinos, KIT) them ideal models to study various aspects of cell function. Mycology: adequate quantities of these materials to Professor Fischer, Professor Riquelme and the tip in order to keep up with the rate of their colleagues, with funding from the growth? Secondly, with such rapid growth Deutsche Forschungsgemeinschaft and occurring at the tip, how does the hypha CONACYT, are studying a host of questions maintain a stable marker of exactly where, and Unravelling the surrounding the growth and development of in what direction, growth is to occur? filamentous fungi. Using multiple species and state-of-the-art microscopy and molecular The logistics of transporting materials to biological methods, they are enhancing our the actively-growing hyphal tip are being understanding of the mechanisms by which elucidated by Michael Feldbrügge’s lab riddle of the these intriguing and important organisms at Heinrich Heine University, Düsseldorf, grow and differentiate. Germany. The length of the hyphae is traversed by a skeleton of fine tubes called KEEPING PACE WITH GROWTH microtubules, along which vesicles and their At the tip of each fungal hypha lies a region contents travel, facilitated by proteins acting filamentous fungi of active growth. Here, membrane-bound as motors. Feldbrügge has also found that particles (vesicles) containing the raw materials these provide transport routes for molecules for building new cell walls and membranes – of messenger RNA, which translate the proteins, lipids and other organic molecules, genetic information in DNA into functional as well as catalytic enzymes – fuse with the proteins. Crucially, this means that protein The fungi are perhaps the least understood of the multicellular here may be as many as five microscopic tip, to form huge networks cell’s boundary membrane, releasing their production can be precisely targeted to million species of fungi worldwide called ‘mycelia’. precious cargo. However, the highly polarised specific regions within a cell without having organisms, despite being almost ubiquitous in nature. An international – many more than there are positioning of this region poses challenges to transport large quantities of the proteins team, coordinated by Professor Dr Reinhard Fischer of the Karlsruhe plants. The vast majority of these UNDERRATED ORGANISMS for the fungus. Firstly, how can they transport themselves. Institute of Technology, Germany, and Professor Dr Meritxell little-understood organisms are Despite their lowly appearance, the Riquelme from the Centro de Investigación Cientifíca y de Educación the ‘filamentous fungi,’ named because filamentous fungi are crucial to the functioning Tthey are composed of a web of filaments of natural ecosystems. Alongside bacteria, Superior de Ensenada, Mexico, is leading attempts to understand the called ‘hyphae’. The work of Professor they are the main agents responsible for The diverse and enlightening findings of this growth and development of these remarkable organisms, shedding Fischer, Professor Riquleme and their co- decomposing dead organic matter, making high-profile programme have implications far light on their medical and ecological applications. workers focuses on how these filaments its chemical components available to the next grow, indefinitely, by extension at each generation of organisms. What is perhaps beyond the fungal kingdom 15 Microbiology Detail RESEARCH OBJECTIVES Professor Reinhard Fischer is currently How numerous, widespread and What recent technological advances studying the filamentous fungus significant are the filamentous fungi? have helped further your research? Aspergillus nidulans. His primary interest Fungi are found in nearly all ecosystems, The advent of molecular biological in this fungus is as a model for spore where they fulfil important functions methods in the 1980s, the use of GFP and mycotoxin formation and the effect for nutrient recycling. Some species and other fluorescent proteins since 1994 of environmental factors on its growth. are important plant pathogens, such as in combination with steadily improved Professor Meritxell Riquelme is studying Magnaporthe oryzae or rust fungi. There microscopy techniques and the recent the mould Neurospora crassa and is are also animal pathogens. Many moulds development of super-resolution interested in the cellular components contaminate food and feed and cause microscopy techniques have boosted enabling indefinite hyphal extension. tremendous losses due to mycotoxin fungal research. 2 µm formation. FUNDING How do the cells of filamentous fungi Deutsche Forschungsgemeinschaft Why is their growth and development differ from those of other organisms? (DFG), Consejo Nacional de Ciencia y Above: In this experiment two enzymes required Fungi are in many aspects identical to Tecnología, Mexico (CONACYT) for cell wall synthesis were visualised in hyphae of such an interesting area to study? Neurospora crassa using two different coloured The fungal hypha is able to grow human cells. One important difference, fluorescent proteins. Whereas an endoglucanase indefinitely at the tip. It is one of the however, is the presence of a rigid cell COLLABORATORS enzyme (BGT-2) localises to the plasma membrane, a chitin synthase (CHS-1) accumulates first in a structure few examples of extreme polar growth wall consisting of different carbohydrate Professors J Aguirre, M Bölker, G Braus, called “Spitzenkörper” before it is secreted. Confocal of individual cells. Other examples are polymers, including chitin. Because of M Feldbrügge, U Fleig, W Hansberg, Laser scanning microscopy images obtained by Dr pollen tubes, root hairs and nerve cells. this difference, the fungal cell wall or the A Herrera-Estrella, R Mouriño-Pérez, J Leonora Martínez-Núñez, CICESE. Thus the study of the mechanisms of biosynthesis machinery may be targets Kämper, U Kück, N Requena, N Takeshita, polar fungal extension may help to for drug development. S Bartnicki-Garcia In answer to the second question, Prof Fischer Close-up images of a colony of N. crassa. The aerial mycelium shows improve our understanding of polarity himself, working with Prof Norio Takeshita, the interwoven fine hyphae. Carotene stains the mycelium orange. in general. Likewise, simple hyphae are Pictures taken by Rosa Aurelia Fajardo Somera from KIT. What biological features are BIO has discovered that in the filamentous able to differentiate rather complicated conserved between filamentous Before becoming Professor for fungus, Aspergillus nidulans, molecules of structures such as fruiting bodies. fungi and animals such as humans? Microbiology at the University a special protein – TeaR – located at the tip This requires massive changes in gene Basic cell biological processes such of Karlsruhe, Prof Dr Reinhard of the hyphae, mark the zone in which active expression. It can be an example for as mitosis, meiosis, the functioning Fischer studied for his PhD in growth is taking place. Using advanced, other differentiation processes, e.g., of organelles, or the principles of gene Microbiology at the University of super-resolution microscopy techniques to embryogenesis in higher eukaryotes. regulation are highly conserved between Marburg. He has represented the DFG visualise the activities of living cells in real humans and both filamentous and as a panel member since 2012 and time, they showed that the cluster of TeaR yeast-like fungi. sits on the editorial boards for a molecules at the hyphal tip is repeatedly number of well-known scientific dispersed and reassembled with newly- journals, including Molecular arriving TeaRs, maintaining an indicator that Microbiology, mSphere and tells the machinery of the cell where to build mBio. Prof Dr Mertixell Riquelme new tissue. genetic approaches, that injury results in the between symbiotic partners. Arbuscule completed a BS in Biology at the production of highly reactive and damaging formation, however,
Load more

Recommended publications
  • Introduction to Mycology
    INTRODUCTION TO MYCOLOGY The term "mycology" is derived from Greek word "mykes" meaning mushroom. Therefore mycology is the study of fungi. The ability of fungi to invade plant and animal tissue was observed in early 19th century but the first documented animal infection by any fungus was made by Bassi, who in 1835 studied the muscardine disease of silkworm and proved the that the infection was caused by a fungus Beauveria bassiana. In 1910 Raymond Sabouraud published his book Les Teignes, which was a comprehensive study of dermatophytic fungi. He is also regarded as father of medical mycology. Importance of fungi: Fungi inhabit almost every niche in the environment and humans are exposed to these organisms in various fields of life. Beneficial Effects of Fungi: 1. Decomposition - nutrient and carbon recycling. 2. Biosynthetic factories. The fermentation property is used for the industrial production of alcohols, fats, citric, oxalic and gluconic acids. 3. Important sources of antibiotics, such as Penicillin. 4. Model organisms for biochemical and genetic studies. Eg: Neurospora crassa 5. Saccharomyces cerviciae is extensively used in recombinant DNA technology, which includes the Hepatitis B Vaccine. 6. Some fungi are edible (mushrooms). 7. Yeasts provide nutritional supplements such as vitamins and cofactors. 8. Penicillium is used to flavour Roquefort and Camembert cheeses. 9. Ergot produced by Claviceps purpurea contains medically important alkaloids that help in inducing uterine contractions, controlling bleeding and treating migraine. 10. Fungi (Leptolegnia caudate and Aphanomyces laevis) are used to trap mosquito larvae in paddy fields and thus help in malaria control. Harmful Effects of Fungi: 1.
    [Show full text]
  • Chapter 13: Ecosystem Mycology: Saprotrophs, and Mutualisms Between Plants and Fungi
    21st Century Guidebook to Fungi, Second Edition of the online version, by David Moore, Geoffrey D. Robson and Anthony P. J. Trinci [URL: http://www.davidmoore.org.uk/21st_Century_Guidebook_to_Fungi_PLATINUM/] Chapter 13: Ecosystem mycology: saprotrophs, and mutualisms between plants and fungi 13.1 Ecosystem mycology 13.2 Fungi as recyclers and saprotrophs 13.3 Make the earth move 13.4 Fungal toxins: food contamination and deterioration 13.5 Decay of structural timber in dwellings 13.6 Using fungi to remediate toxic and recalcitrant wastes 13.7 Release of chlorohydrocarbons to the atmosphere by wood decay fungi 13.8 Introduction to mycorrhizas 13.9 Types of mycorrhiza 13.10 Arbuscular (AM) endomycorrhizas 13.11 Ericoid endomycorrhizas 13.12 Arbutoid endomycorrhizas 13.13 Monotropoid endomycorrhizas 13.14 Orchidaceous endomycorrhizas 13.15 Ectomycorrhizas 13.16 Ectendomycorrhizas 13.17 The effects of mycorrhizas and their commercial applications, and the impact of environmental and climate changes 13.18 Introduction to lichens 13.19 Introduction to endophytes 13.20 Epiphytes 13.21 Chapter 13 References and further reading Chapter 13: Ecosystem mycology: saprotrophs, and mutualisms between plants and fungi In this Chapter on ecosystem mycology we cover fungi as saprotrophs, and the mutualisms between plants and fungi, concentrating on fungi as recyclers that can make the earth move. Fungi also cause food contamination and deterioration through their formation of toxins, although some of these, like statins and strobilurins, are exploited commercially for our own practical purposes. The ability of fungi to degrade wood makes them responsible for the decay of structural timber in dwellings, but on the other hand enables them to be used to remediate toxic and recalcitrant wastes.
    [Show full text]
  • Basidiomycete Mycelia in Forest Soils: Dimensions, Dynamics and Roles in Nutrient Distribution
    Mycol. Res. 109 (1): 7–20 (January 2005). f The British Mycological Society 7 DOI: 10.1017/S0953756204001753 Printed in the United Kingdom. Review Basidiomycete mycelia in forest soils: dimensions, dynamics and roles in nutrient distribution John W. G. CAIRNEY Centre for Horticulture and Plant Sciences, University of Western Sydney, Parramatta Campus, Locked Bag 1797, Penrith South DC, NSW 1797, Australia. E-mail: [email protected] Received 15 July 2004; accepted 3 October 2004. Basidiomycete mycelia are ubiquitous in forest soils where they fulfil a range of key ecological functions. Population studies, based largely on basidiome collections, indicate that mycelia of many ectomycorrhizal and saprotrophic basidiomycetes can spread vegetatively for considerable distances through soil, but the extent to which these become physically or physiologically fragmented is unclear. This review considers aspects of the distribution, dynamics and translocatory activities of individual basidiomycete mycelia in forest soil, highlighting current gaps in our understanding and possible ways to address these. INTRODUCTION in soil have been constrained by a lack of suitable techniques for discrimination between them, but some On the basis of basidiome collections, it is evident that progress is now being made. A useful method for esti- forest soils in a broad range of habitats house diverse mating ECM mycelial biomass in forest soils has, for communities of basidiomycetes (e.g. Schmit, Murphy example, recently been developed (Wallander et al. & Mueller 1999, de la Luz Fierros, Navarrete-Heredia 2001). This involves burying mesh bags containing & Guzma´n-Davalos 2000, Ferris, Peace & Newton sand in forest plots and comparing mycelial biomass in 2000, Packham et al.
    [Show full text]
  • Hypha and Its Characteristics
    Clinical Microbiology: Open Access Commentary Hypha and its Characteristics Giusina Caggiano* Department of Biomedical Sciences, University of Bari, Bari, Italy DESCRIPTION growing tip, dividing the hypha into individual cells. Hyphae can branch by the bifurcation of a growing tip or by the emergence A fungus or actinobacterium's hypha is a long, branching of a new tip from an existing hypha. The behaviour of hypha can filamentous structure. Hyphae are the primary mode of be described as follows: environmental stimuli, such as the vegetative growth and are referred to collectively as a mycelium. application of an electric field, can control the direction of A hypha is made up of one or more cells that are surrounded by hyphal growth. Hyphae can detect reproductive units from afar a tubular cell wall. Most fungi divide their hyphae into cells via and grow towards them. To penetrate a permeable surface, internal cross-walls known as "septa". Septa are typically hyphae can weave through it. Hyphae can be modified in a perforated by pores large enough to allow ribosomes, variety of ways to perform specific functions. Some parasitic mitochondria, and occasionally nuclei to pass between cells. In fungi develop haustoria that aid in absorption within host cells. contrast to plants and oomycetes, which have cellulosic cell walls, Arbuscules of mutualistic mycorrhizal fungi perform a similar the major structural polymer in fungal cell walls is typically function in nutrient exchange and are therefore important in chitin. Some fungi have aseptate hyphae, which mean that their assisting plant nutrient and water absorption. In lichens, hyphae hyphae are not divided by septa.
    [Show full text]
  • 6 Infections Due to the Dimorphic Fungi
    6 Infections Due to the Dimorphic Fungi T.S. HARRISON l and S.M. LEVITZ l CONTENTS VII. Infections Caused by Penicillium marneffei .. 142 A. Mycology ............................. 142 I. Introduction ........................... 125 B. Epidemiology and Ecology .............. 142 II. Coccidioidomycosis ..................... 125 C. Clinical Manifestations .................. 142 A. Mycology ............................. 126 D. Diagnosis ............................. 143 B. Epidemiology and Ecology .............. 126 E. Treatment ............................. 143 C. Clinical Manifestations .................. 127 VIII. Conclusions ........................... 143 1. Primary Coccidioidomycosis ........... 127 References ............................ 144 2. Disseminated Disease ................ 128 3. Coccidioidomycosis in HIV Infection ... 128 D. Diagnosis ............................. 128 E. Therapy and Prevention ................. 129 III. Histoplasmosis ......................... 130 I. Introduction A. Mycology ............................. 130 B. Epidemiology and Ecology .............. 131 C. Clinical Manifestations .................. 131 1. Primary and Thoracic Disease ......... 131 The thermally dimorphic fungi grow as molds in 2. Disseminated Disease ................ 132 the natural environment or in the laboratory at 3. Histoplasmosis in HIV Infection ....... 133 25-30 DC, and as yeasts or spherules in tissue or D. Diagnosis ............................. 133 when incubated on enriched media at 37 DC. E. Treatment ............................
    [Show full text]
  • Hyphal Tip Growth: Outstanding Questions
    Bartnicki-Garcia HYPHAL TIP GROWTH: OUTSTANDING QUESTIONS Salomón Bartnicki-García Centro de Investigación Científica y de Educación Superior de Ensenada (CICESE), Ensenada, México and Department of Plant Pathology, University of California, Riverside, California. I. GENERAL 2 II. KEY STRUCTURES AND PROCESSES IN TIP GROWTH 2 A. THE CENTRAL QUESTION - POLARIZED SECRETION.....................................................................................2 B. THE SPITZENKÖRPER .................................................................................................................................3 1. Organizer of vesicle traffic ..................................................................................................................3 2. The Spitzenkörper as a Vesicle supply Center (VSC) .............................................................................4 3. Spitzenkörper Trajectory ......................................................................................................................6 4. Growth Pulses and Satellite Spitzenkörper............................................................................................6 5. Spitzenkörper origin.............................................................................................................................7 6. Questions.............................................................................................................................................7 C. THE CYTOSKELETON .................................................................................................................................8
    [Show full text]
  • Diversity Recognition of the Discipline of Conservation Mycology
    Diversity Recognition of the discipline of conservation mycology Tom W. May ,1 ∗ Jerry A. Cooper,2 Anders Dahlberg,3 Giuliana Furci,4 DavidW.Minter,5 Gregory M. Mueller,6 Alison Pouliot,7 and Zhuliang Yang8 1Royal Botanic Gardens Victoria, Birdwood Avenue, Melbourne, VIC 3004, Australia 2Manaaki Whenua – Landcare Research, 54 Gerald Street, Lincoln 7608, New Zealand 3Department of Forest Mycology and Plant Pathology, Swedish University of Agricultural Sciences, P.O. Box 7026, 750 07 Uppsala, Sweden 4Fundacion´ Fungi, Paseo Bulnes 79 oficina 112A, Santiago, Chile 5CABI, Bakeham Lane, Egham, Surrey TW20 9TY, U.K. 6Chicago Botanic Garden, 1000 Lake Cook Road, Glencoe, IL 60022, U.S.A. 7Fenner School, Australian National University, Linnaeus Way, Canberra, ACT 2601, Australia 8Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, Yunnan, China Fungi constitute one of the major lineages of life (organ- ing literature explicitly dealing with fungi conservation isms treated as fungi are also scattered in other lineages). (Moore et al. 2001; Heilmann-Clausen et al. 2014). Kingdom Fungi are quite separate to Animalia and Plan- Recent innovations and initiatives in the way fungi are tae, but fungi are intimately connected to other biota studied and regarded mean it is timely to recognize the through food webs and symbioses as decomposers, en- discipline of conservation mycology within conservation dophytes, pathogens, lichens, and mycorrhizas. During science. Advances include acceptance of fungi as a ma- much of the 20th century, fungi were either ignored jor unit of biota, alongside flora and fauna (Pouliot & or perceived as intractable in conventional conserva- May 2010; Minter 2011); recognition that most fungal tion initiatives.
    [Show full text]
  • The Lifecycle of a Mushroom
    WEB TUTORIAL 21.1 The Lifecycle of a Mushroom Text Sections Section 21.3 Reproduction in Fungi, p. 354 Introduction Mushrooms have an unusual life cycle. After spores are released from mature fruit- ing bodies, they germinate to form hyphae. Collectively, the hyphae make up a branching web, called a mycelium. Hyphae derived from the spores of two differ- ent mating types then fuse to become one cell with two distinct nuclei. Thus begins a phase of life that is unique to fungi: the dikaryotic phase, in which cells in a fun- gal mycelium have two nuclei. This tutorial illustrates the relationships among these phases in the life cycle of a mushroom. Learning Objectives • Know the structures involved in each stage of a mushroom’s life cycle. • Understand why the life cycle of fungi is unique in the tree of life. Narration The Life Cycle of a Mushroom A mushroom is a member of a group of fungi called the Basidiomycota. Let's con- sider its life cycle, beginning with the spores that are produced by the mature fruit- ing body. A spore germinates, dividing by mitosis to produce a filament called a hypha. The hypha grows and branches to produce a filamentous network called a mycelium. The mycelium has a high surface-area-to-volume ratio, which allows the fungus to absorb nutrients efficiently. If the hyphae of different mating types meet, they are attracted to each other and fuse, forming a cell with two nuclei. This is an unusual condition for a cell; in the normal case, one cell has one nucleus.
    [Show full text]
  • Introductory Mycology BI 432/532 Lecture 2: Overview of Fungi
    Introductory Mycology BI 432/532 Lecture 2: Overview of Fungi " Fungi are:! •# Microbes (mostly)! •# Eukaryotic, heterotrophic organisms that obtain nutrients by absorption and reproduce by spores. " "Extracellular enzymes act on complex substrates, low molecular weight breakdown products are absorbed through the fungal cell wall." " "Fungi live in their food." Nutrition" •# Heterotrophs (chemoheterotrophs)! •# Aerobes, facultative anaerobes (except Neocallimastix)" •# Absorptive nutrition" •# Secrete extracellular enzymes that act on complex substrates " •# Saprobes: decay dead organic matter" •# Parasites: biotroph, necrotroph " " Reproduce by spores! Reproduction, dissemination or survival structures" " A differentiated structure that may be specialized for dissemination, a resistant structure produced in response to adverse conditions, and/or produced during or as a result of a sexual or asexual reproductive process." " Spores may be one-celled or multicelled, colorless or pigmented (brown)" Fungal spores" Spores of some true fungi (chytrids), and fungus- like taxa (Oomycetes) are motile zoospores" Chytrid zoospores" have a single" posteriorly directed" flagellum" " Oomycetes" fungus-like organisms more closely related to plants than to true fungi" Oomycete zoospores have two flagella," one anteriorly directed and one posteriorly" directed" Spores of “higher fungi”—zygomycetes, ascomycetes, basidiomycetes— are non-motile" Spores of fungi may result from sexual (meiotic division) or asexual (mitotic division) processes" Major groups of
    [Show full text]
  • When Mycologists Describe New Species, Not All Relevant
    A peer-reviewed open-access journal MycoKeys 72: 109–128 (2020) Mycological species descriptions over time 109 doi: 10.3897/mycokeys.72.56691 RESEARCH ARTICLE MycoKeys http://mycokeys.pensoft.net Launched to accelerate biodiversity research When mycologists describe new species, not all relevant information is provided (clearly enough) Louisa Durkin1, Tobias Jansson1, Marisol Sanchez2, Maryia Khomich3, Martin Ryberg4, Erik Kristiansson5, R. Henrik Nilsson1 1 Department of Biological and Environmental Sciences, Gothenburg Global Biodiversity Centre, University of Gothenburg, Box 461, 405 30 Göteborg, Sweden 2 Department of Forest Mycology and Plant Pathology, Uppsala Biocentre, Swedish University of Agricultural Sciences, Uppsala, Sweden 3 Nofima – Norwegian Institute of Food, Fisheries and Aquaculture Research, P.O. Box 210, 1431 Ås, Norway 4 Department of Organismal Biology, Uppsala University, Uppsala, Sweden 5 Department of Mathematical Sciences, Chalmers University of Technology and University of Gothenburg, Göteborg, Sweden Corresponding author: R. Henrik Nilsson ([email protected]) Academic editor: T. Lumbsch | Received 19 July 2020 | Accepted 24 August 2020 | Published 10 September 2020 Citation: Durkin L, Jansson T, Sanchez M, Khomich M, Ryberg M, Kristiansson E, Nilsson RH (2020) When mycologists describe new species, not all relevant information is provided (clearly enough). MycoKeys 72: 109–128. https://doi.org/10.3897/mycokeys.72.56691 Abstract Taxonomic mycology struggles with what seems to be a perpetual shortage
    [Show full text]
  • Lin, Xiaorong Professor
    BIOGRAPHICAL SKETCH NAME POSITION TITLE Lin, Xiaorong Professor EDUCATION/TRAINING INSTITUTION AND LOCATION DEGREE YEAR(s) FIELD OF STUDY B.S. Dalian University of Technology, China 1992-1996 Chemical Engineering (honors) Dalian Institute of Chemical Physics, China M.S. 1996-1999 Chemical Engineering Molecular Genetics and University of Georgia Ph.D. 1999-2003 Fungal Biology Duke University Medical Center Postdoc 2003-2007 Medical Mycology A. Positions and Honors. Positions and Employment 1996 – 1999 Graduate Research Assistant, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, China 1999 – 2003 Graduate Research Assistant, Department of Plant Biology, University of Georgia, GA 2003 – 2007 Postdoctoral Research Associate, Department of Molecular Genetics and Microbiology, Duke University Medical Center, NC 2008 – 2013 Tenure-Track Assistant Professor, Department of Biology, Texas A&M University, TX 2013 – 2017 Associate Professor with tenure, Department of Biology, Texas A&M University, TX (Promoted to Professor in 2017) 2014 – 2017 Adjunct faculty, Department of Microbiology and Immunology, Texas A&M Health Science Center, TX 2017 – present Professor, Department of Microbiology, University of Georgia, GA 2018 – present Adjunct Professor, Department of Plant Biology, Department of Infectious Diseases, University of Georgia, GA Honorary Memberships 2018 – present Fellow, American Association for the Advancement of Science (AAAS) 2019 – present Fellow, American Academy of Microbiology (AAM) Professional Membership 2001
    [Show full text]
  • Medical Microbiology
    Medical Microbiology Li Mei Department of Microbiology November, 2006 Chapter 17, 18 Medical Mycology ­­­Fungi Non­cellular Prokaryotic Eukaryotic microorganisms microorganisms microorganisms Introduction • Fungi are eukaryotic organisms, and each fungal cell has at least one nucleus enclosed by a nuclear membrane, endoplasmic reticulum, mitochondria, and secretory apparatus, they do not contain chlorophyll. What is the relationship between Fungi and Humans? Morel n Widely exist n ~50,000 species, n Be beneficial to human p biodegradation p source of food p the preparation of food p antibiotics n Widely exist n ~50,000 species, n Be beneficial to human p biodegradation p source of food p the preparation of food p antibiotics • Be harmful to human – ~300 species, pathogenic for human – Mycoses Medically important fungi • Ascomycetes • Basidiomycetes • Zygomycetes • Deuteromycetes Ascomycetes ­­Sexual reproduction: ascus, ascospores. Basidiomycetes ­­Sexual reproduction: basidiospores on a basidium (basidia). Basidiomycetes Zygomycetes p Sexual reproduction the fusion of haploid mating hypha to produce diploid zygospores p Asexual reproduction spores in stalked sporangia Deuteromycetes q Imperfect fungi, no recognizable form of sexual reproduction. q Many are of medical significance. Aspergillus Penicillium I. Morphology Cocci 0.8 µm Bacilli 4­6 µm Spirochetes 8 ­ 10 µm A. Size: Viruses 0.08 µm B. Structure of the fungal cell: Fungi 10 – 15 µm p Cell wall chitin, proteins, polysaccharides, lipids p Cell membrane ergosterol, instead of cholesterol
    [Show full text]