Fungi and Their Functions Quiz
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Questions and Answers

Which of the following fungi are used as biopesticides?

  • Trichoderma
  • Alternaria (correct)
  • Colletotrichum (correct)
  • Metarhizium sp (correct)
  • Beauveria bassiana (correct)

Fungal cells, like animal cells, contain cholesterol in their plasma membranes.

False (B)

What is the name of the threadlike structures that make up the body of a mold?

hyphae

The ______ body is a dense mass of vesicles that controls cell wall synthesis at the hyphal tip.

<p>Spitzenkörper</p> Signup and view all the answers

Match the following fungal components with their functions:

<p>Ergosterol = A sterol molecule that modulates fluidity and permeability of the fungal plasma membrane. Woronin bodies = Protect hyphae from injury by plugging septal pores. Chitin = A polymer that provides osmotic stability to the fungal cell wall. Spitzenkörper = Dense mass of vesicles controlling cell wall synthesis at the hyphal tip.</p> Signup and view all the answers

White rot fungi can only degrade pesticides but not oil pollution in soil.

<p>False (B)</p> Signup and view all the answers

Which of the following is NOT a component of the fungal cell wall?

<p>cellulose (B)</p> Signup and view all the answers

Fungi that can exist in both yeast and mold forms are called ______ fungi.

<p>dimorphic</p> Signup and view all the answers

What is the name of the mat-like structure formed by hyphae in molds?

<p>mycelium</p> Signup and view all the answers

Bud formation in yeasts is regulated throughout the cell cycle, typically producing two daughter cells at each mitotic division.

<p>False (B)</p> Signup and view all the answers

The fungus ________ was responsible for the Irish potato famine.

<p>Phytophthora infestans</p> Signup and view all the answers

Which of the following is NOT a way that fungi are used by humans?

<p>Photosynthesis (D)</p> Signup and view all the answers

Match the following fungi with their respective uses:

<p>Saccharomyces cerevisiae = Beer and wine production Penicillium = Antibiotic production Fusarium venetatum = Meat substitute (Qorn) Aspergillus = Shake production</p> Signup and view all the answers

Fungi are only beneficial to humans.

<p>False (B)</p> Signup and view all the answers

What is the role of fungi in the ecosystem?

<p>Decomposers</p> Signup and view all the answers

Which type of fungus forms a symbiotic relationship with plants?

<p>Mycorrhiza (D)</p> Signup and view all the answers

The fungus ________ is used to ferment dough for bread.

<p>Saccharomyces cerevisiae</p> Signup and view all the answers

More than 2 million tons of Shiitake mushrooms are produced worldwide each year.

<p>False (B)</p> Signup and view all the answers

Approximately how many species of fungi are currently known?

<p>150,000 (D)</p> Signup and view all the answers

All known fungi are considered pathogens.

<p>False (B)</p> Signup and view all the answers

Name one fungal species that poses a threat to plants.

<p>Magnaporthe oryzae</p> Signup and view all the answers

Fungi are considered to be ______ microorganisms, such as yeasts and molds.

<p>eukaryotic</p> Signup and view all the answers

Which of the following is NOT a factor contributing to fungi-host dynamics leading to host extinction?

<p>short-lived environmental stages (C)</p> Signup and view all the answers

Fungal alerts have decreased between 1995-2010.

<p>False (B)</p> Signup and view all the answers

What is the name of the fungal pathogen that affects bats?

<p>Geomyces destructans</p> Signup and view all the answers

Fungi have one of the highest mortality rates for human pathogens, exceeding ______ percent.

<p>80</p> Signup and view all the answers

Match the following fungal species with their host type:

<p>Batrachochytrium dendrobatidis = Amphibians Magnaporthe oryzae = Plants Geomyces destructans = Bats Nosema species = Insects</p> Signup and view all the answers

According to the materials which type of patients are more susceptible to severe fungal infections?

<p>Immunosuppressed patients (C)</p> Signup and view all the answers

What is the primary purpose of DNA methylation in fungi?

<p>Act as a genome defense against transposable elements (TEs) (C)</p> Signup and view all the answers

Histopathology is considered a traditional approach to diagnosing fungal infections.

<p>True (A)</p> Signup and view all the answers

What are the two regions called that are part of the internal transcribed spacer (ITS) sequences?

<p>ITS1 and ITS2</p> Signup and view all the answers

The challenge in diagnosing invasive fungal disease (IFD) lies in the lack of __________ and __________ in current diagnostic methods.

<p>sensitivity, specificity</p> Signup and view all the answers

Match the following diagnostic methods with their approaches:

<p>Direct microscopic examination = Visual analysis of clinical samples Culture = Growing fungi in a controlled environment Serology = Detecting antibodies or antigens Molecular diagnostics = Analyzing genetic material</p> Signup and view all the answers

What is the mortality rate of Aspergillus species?

<p>30%-95% (A)</p> Signup and view all the answers

Mucormycosis is associated with COVID-19 only in patients with controlled diabetes.

<p>False (B)</p> Signup and view all the answers

Which fungus is known to cause late blight disease in potatoes?

<p>Phytophthora infestans</p> Signup and view all the answers

Fungal diseases cost American farmers $_____ billion annually.

<p>3.2</p> Signup and view all the answers

Match the following fungi with their associated diseases or impacts:

<p>Cordyceps = Human pathogens Aspergillus spp = Respiratory disease (mycosis) Claviceps purpurea = Ergotism Phytophthora infestans = Late blight disease in potatoes</p> Signup and view all the answers

How many major classes of antifungal drugs are there?

<p>Four (A)</p> Signup and view all the answers

Phytophthora infestans results in annual losses greater than $3 billion worldwide.

<p>True (A)</p> Signup and view all the answers

What is the urgent need regarding antifungal drugs?

<p>Need for new antifungal drugs</p> Signup and view all the answers

What is the term for the form of fungus that produces asexual spores?

<p>Anamorph (A)</p> Signup and view all the answers

Fungi reproduce exclusively asexually.

<p>False (B)</p> Signup and view all the answers

What are the spores produced by Ascomycetes called?

<p>Ascospores</p> Signup and view all the answers

A basidiocarp is also known as a ______.

<p>basidioma</p> Signup and view all the answers

Which type of reproduction involves the recombination of genes without meiosis?

<p>Parasexuality (A)</p> Signup and view all the answers

Match the following types of fungi with their respective sexual spores:

<p>Ascomycetes = Ascospores Basidiomycetes = Basidiospores Zygomycetes = Zygospores</p> Signup and view all the answers

Heterothallic fungi have both mating types in the same body.

<p>False (B)</p> Signup and view all the answers

What process results from the fusion of two haploid nuclei that generates diversity?

<p>Mitotic crossing over</p> Signup and view all the answers

Flashcards

Human pathogenic fungi

Fungi causing diseases in humans.

Mycosis

A severe fungal infection.

Aspergillus

A genus of fungi that can cause life-threatening respiratory infections.

Mucormycosis

A fungal infection associated with COVID-19 in diabetic patients.

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Plant pathogens

Fungi that cause diseases in plants.

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Powdery mildew

A fungal disease that causes powdery white patches on plants.

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Damping-off

A fungal disease that causes the death of seedlings, often near the soil line.

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Late blight

A serious disease that causes significant losses in potato crops.

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What are fungi?

Fungi are eukaryotic microorganisms, including yeasts and molds, with over 150,000 known species.

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How many fungi are unknown to science?

It's estimated that 90% of fungal species are still undiscovered.

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What percentage of fungi have medical relevance?

About 80% of fungi are medically important, causing infections in humans and animals.

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What is mycology?

The study of fungi, including their classification, characteristics, and interactions with other organisms.

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What are pathogens?

Organisms that cause diseases in other organisms.

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Why is the surge in fungal infections concerning?

Fungal infections are increasing, especially in animals and plants, threatening biodiversity, and posing a significant risk of species extinction.

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What is Batrachochytrium dendrobatidis?

A disease caused by a fungus that impacts amphibians. It is contributing to their decline.

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What is Candida?

A fungus that causes infections in plants and animals, with the potential for severe consequences.

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Why are fungi considered opportunistic human pathogens?

Opportunistic human pathogens often causing severe infections in individuals with compromised immune systems, leading to high mortality rates.

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Who are immunosuppressed patients?

Individuals susceptible to fungal infections due to weakened immune systems caused by factors like illnesses or medications.

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Fungi as Decomposers

Responsible for breaking down dead organic matter and returning nutrients to the soil.

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Mycorrhiza

A mutually beneficial relationship where fungi help plants absorb nutrients from the soil.

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Alcohol Fermentation

Using yeast to produce alcohol, such as beer and wine, by fermenting sugars in the absence of oxygen.

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Penicillin

A powerful antibiotic produced by the fungus Penicillium that revolutionized medicine by treating bacterial infections.

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Bioremediation

Using fungi to break down and remove harmful pollutants from the environment.

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Biofuel Production

The process of converting plant materials into biofuels, often using yeasts or other fungi to ferment sugars.

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Cheese Production (using fungi)

Using fungi to enhance the flavor and texture of cheese during ripening.

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Baking (using fungi)

Fungi, like Saccharomyces cerevisiae, used for thousands of years to ferment dough for baking bread.

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White rot fungi

Fungi that break down organic matter, like pesticides and oil, in the soil. They release nutrients back into the soil.

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Biopesticides

Fungi used to control pests, such as insects, weeds, and other fungi.

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Beauveria bassiana

A fungal species that can be used as a biopesticide against insects.

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Metarhizium sp

A group of fungal species that can be used as biopesticides against insects.

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Alternaria and Colletotrichum

Fungal species used to control weeds.

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Trichoderma, Clonostachys, Ampelomyces

Fungal species that can be used to control other fungi.

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Yeasts

A type of fungal cell, usually unicellular and forming round, pasty colonies on agar.

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Molds

A type of fungal cell, multicellular and forming thread-like structures called hyphae.

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Hyphae

The thread-like structures that make up the body of a mold, forming a mat-like structure called a mycelium.

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Dimorphic fungi

A fungal organism that can exist as both a yeast and a mold, depending on the temperature.

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Repeat Induced Point Mutations (RIP)

A defense mechanism in fungi that protects their genome from invading DNA like transposons, by introducing mutations into the invading DNA.

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Sequence Variability in ITS regions

A unique property of some fungal DNA sequences, particularly in the internal transcribed spacer (ITS) regions, that makes them ideal targets for identifying specific fungal species.

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Challenges in Diagnosing Invasive Fungal Disease (IFD)

A challenging aspect of diagnosing invasive fungal infections, characterized by a lack of sensitivity and specificity in current diagnostic methods. This often leads to delayed diagnoses and treatment.

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Ribosomal DNA (rDNA) Sequencing

A diagnostic method utilizing specific gene sequences within the fungal ribosome to identify fungal species. It is highly effective due to the variability of these sequences across different fungal species.

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Internal Transcribed Spacer (ITS) sequences

A section of fungal DNA involved in ribosome biogenesis, specifically the ITS1 and ITS2 regions, which show significant variability between fungal species, making them useful in species identification.

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Dikaryotic (heterokaryon) lifecycle

A fungal lifecycle where two haploid nuclei with different genetic backgrounds coexist in a single cell without fusing immediately. This is common in Basidiomycota.

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Asexual reproduction in fungi

Asexual reproduction is the primary mode of reproduction in fungi. It involves the creation of spores without the need for sexual fusion.

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Anamorph (asexual)

The form of a fungus that produces asexual spores. Anamorphs represent the asexual stage of a fungus.

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Teleomorph (sexual)

The form of a fungus that produces sexual spores. Teleomorphs represent the sexual stage of a fungus.

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Ascocarp (ascoma)

A fruiting body produced by ascomycetes, containing asci (sac-like structures) that hold ascospores.

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Basidiocarp (basidioma)

A fruiting body produced by basidiomycetes, where sexually produced spores develop on club-shaped structures called basidia.

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Parasexuality

A process of genetic recombination in fungi that does not involve meiosis. It occurs when two haploid nuclei fuse, followed by mitotic crossing over.

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Transposable elements (TEs)

DNA segments that can move within a genome, often altering gene function and structure.

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Study Notes

Introduction to Mycology

  • Mycology is the study of fungi
  • Georgios Tzelepis, Senior lecturer in the Department of Forest Mycology and Plant Pathology at SLU (Swedish University of Agricultural Sciences) presented the course on January 2025.

Course Outline

  • The course ran from January 20th to 31st
  • Course topics included introduction to mycology, evolution and systematics of fungi, genetics and molecular biology of fungi, ecology of fungi, pathogenic fungi (parts 1, 2, and 3), antibiotics, mycotoxins, fungal plant pathogens, and beneficial fungi.
  • Required course components included 2 lab exercises, 1 seminar presentation, 1 key-note speaker seminar, and a written exam.

Course Book

  • The required textbook is Medical Microbiology 9th edition by Murray, Rosenthal, and Pfaller.
  • Section 6: Mycology
  • Exam questions will be based on the lectures.

Fungi

  • Fungi are eukaryotic microorganisms like yeasts and molds, encompassing approximately 150,000 species.
  • An estimated 90% of fungal species are currently unknown.
  • This large, diverse fungal kingdom belongs to Domain Eukarya.

Fungi as Pathogens

  • Significant fungal organisms posing threats to various plants and animals:
    • Magnaporthe oryzae
    • Batrachochytrium dendrobatidis
    • Nosema species
    • Geomyces destructans
  • Fungi pose a substantial threat to species extinction.
  • Fungal alerts have been increasing, especially concerning animal-infecting species, between 1995 and 2010.
  • Substantial host loss occurred in the latter half of the 20th century.
  • Factors contributing to fungal host extinction include
    • high virulence and mortality rate,
    • long-lived environments,
    • broad host range,
    • human activities,
    • accelerated evolution.

Fungi as Human Pathogens

  • Fungi are opportunistic pathogens (no non-pathogenic fungi).
  • They are highly prevalent in immunosuppressed patients, with fatality rates exceeding 80%.
  • The global population of immunosuppressed individuals is increasing.
  • COVID-19 is a concerning factor.
  • Human pathogenic fungi only comprise a small portion of the immense fungal variety in nature.
  • The WHO has identified fungal infections as a global health concern for the first time.
  • Examples of critical, high, and medium groups of fungal human pathogens are provided, including species like Cryptococcus neoformans, Candida auris, Aspergillus fumigatus, Candida albicans, Histoplasma spp., etc.

Fungi as Plant Pathogens

  • Fungi are a major threat to plant health.
  • They cause diverse symptoms like powdery mildew, necrotic spots, rust symptoms, and damping-off.
  • Fungal diseases cost American farmers $3.2 billion annually.
  • Fungicide application costs add another $158 million annually.
  • Numerous ergotism epidemics occurred in Europe during the 16th and 18th centuries, attributed to the fungus Claviceps purpurea.
  • Fungi also cause significant losses in quality and value for fruits, vegetables during transportation, storage, and marketing.
  • Phytophthora infestans causes late blight disease in potatoes; a devastating disease contributing to considerable losses (> $3 billion annually).
  • Phytophthora infestans was responsible for the devastating Irish Potato Famine (1845-1852), causing the death of one million and the emigration of another. The Irish population dropped by 20-25% due to the famine.

Fungi as Friends

  • They are essential decomposers in nature, breaking down organic matter to return essential nutrients to the soil.
  • Some form mycorrhizal symbiosis with plants, aiding in nutrient acquisition.
  • Humans have used fungi for thousands of years in food production (e.g., baking, brewing, cheesemaking).
  • Fungi are used in various aspects of medicine.
  • Sources of biofuels.
  • Degradation of pesticides and oil-polluted soil (bioremediation).
  • Sources of biopesticides to combat insects and weeds.

Basics in Fungal Biology

  • Fungi are eukaryotes with a nucleus, plasma membrane, mitochondria, and an endomembrane system.
  • Fungi are categorized as either yeasts (unicellular) or molds (filamentous fungi).
  • Many medically important fungi are dimorphic (can exist as yeast or mold forms depending on temperature).
  • Fungal cells contain specialized structures like endoplasmic reticulum, Golgi apparatus, vacuoles, vesicles, nucleus, and a cytoskeleton (including woronin bodies).
  • The cell wall comprises glucans, chitin, and proteins.
  • Ergosterol, a fungal sterol, is a key component of fungal plasma membranes

Fungal Growth and Cell Division

  • Budding in yeasts is controlled throughout the cell cycle.
  • Daughter cells originate from the mother cell through mitotic division.
  • Daughter cells can elongate, forming pseudohyphae.
  • Spitzenkörper (a dense mass of vesicles) is involved in cell wall synthesis at the hyphal tip.

Fungal Life Cycles and Reproduction

  • Fungi demonstrate various life cycles, including haploid (most common), diploid, and dikaryotic (heterokaryotic) life cycles.

Fungal Reproduction

  • Asexual reproduction (e.g., sporangia, conidia, chlamydospores) is common.
  • Sexual reproduction (e.g., ascospores, basidiospores, zygospores) involves different fungal mating types (homothallic or heterothallic).
  • Ascocarp/ascoma is the fruiting body of ascomycetes
  • Basidiocarp/basidioma is the fruiting body of basidiomycetes.

Fungal Genome Recombination

  • Transposable elements (TEs) can move within the genome to alter gene architecture and function.
  • Horizontal gene transfer (HGT) can occur between fungi and other organisms (e.g., bacteria, plants).
  • Epigenetic modifications like DNA methylation may influence fungal genomes, potentially protecting against transposable elements and other foreign DNA.
  • Repeat-induced point mutations (RIP) is a unique process in fungi to protect its genome

Diagnostics in Medical Mycology

  • Early diagnosis of fungal infections is crucial for successful treatment.
  • Traditional diagnostics include direct microscopic examination, histopathology, culture, and serology.
  • Emerging techniques include molecular diagnostics and antigen detection using molecular or immunoassay platforms.
  • Invasive fungal diseases (IFDs) present a diagnostic challenge due to challenges with sensitivity, specificity, and timeliness of traditional methods.
  • Sequencing of fungal ribosomal targets (e.g., ITS sequences) is a well-established molecular diagnostic method because it showcases the differences between fungal species.
  • Various types of samples (e.g., oral cavity swabs, blood samples, urine samples, skin swabs) can be used for analyzing fungal pathogens. Diagnostics typically take 4–10 days for completing the entire process.

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Introductory Mycology Lecture (PDF)

Description

Test your knowledge on fungi, their structures, and their roles in the environment. This quiz covers essential concepts such as biopesticides, the structure of molds, and the functions of various fungal components. Explore the wide-ranging implications of fungi in ecology and human use.

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