MIcrobio FUNGI

What is the estimated number of fungi species?

Around 1.5 million species.

What percentage of fungi species have been formally classified?

About 5%.

What are the main types of organisms classified under fungi?

Yeast, mold, and mushrooms.

How do fungi obtain their nutrients?

By absorption of simple organic compounds.

What is the study of fungi called?

Mycology.

What are fungal diseases referred to as?

Mycoses.

What role do fungi play in the ecosystem?

They are major decomposers of organic materials in the soil.

What do fungi recycle in the environment?

Carbon, nitrogen, phosphorus, and other elements.

What are the two major groups of fungi?

Filamentous fungi (molds) and unicellular fungi (yeasts).

What is the structure of fungal cells?

They contain membrane-bound nuclei with chromosomes that contain DNA.

What is the composition of the fungal cell wall?

Glucans and chitin.

What is the typical growth temperature for most fungi?

About 25°C, except for pathogens which grow at 37°C.

What type of organisms are fungi classified as?

Heterotrophic organisms.

What is the term for the tangled mass of hyphae visible to the naked eye?

Mycelium.

What are hyphae?

Cylindrical, thread-like structures that make up the body of molds.

What is the difference between coenocytic and septate fungi?

Coenocytic fungi lack cross walls, while septate fungi have cross walls (septa) dividing the hyphae.

How do yeasts reproduce?

By budding.

What is the significance of dimorphic fungi?

They can switch between a yeast phase and a hyphal phase in response to environmental conditions.

What type of environments do fungi typically inhabit?

Terrestrial environments, but some live in aquatic habitats.

What is the growth rate of fungi compared to bacteria?

Fungi grow at a slower rate than bacteria.

What is the spore structure in fungi called?

Conidia.

What are the two types of fungal growth forms?

Filamentous (molds) and unicellular (yeasts).

What is the typical pH range for optimal fungal growth?

About 5 (acidic pH).

What are yeasts?

Microscopic, unicellular fungi with a single nucleus and eukaryotic organelles that reproduce asexually by budding.

What is the process of budding in yeasts?

A new cell forms at the surface of the original cell, enlarges, and then breaks free to assume an independent existence.

What are dimorphic fungi?

Fungi that can shift between yeast form and mold form, often seen in fungal pathogens.

How do fungi typically reproduce?

Fungi reproduce through spores, which can be produced by sexual or asexual means.

What are conidia?

A type of asexual spore that is free and unprotected at the tips of hyphae.

What are sporangiospores?

Asexual spores formed within a sac.

Why are fungal spores important?

They are unique in shape, color, and size, aiding in identification and classification of fungi.

What is the significance of a single spore in fungi?

A single spore can germinate and reestablish the entire mycelium.

What are the types of asexual spores in fungi?

Conidia, sporangiospores, arthrospores (fragments of hyphae), and chlamydospores (thick-walled spores).

How does asexual reproduction in fungi occur?

Through the formation of spores by mitosis.

What is the role of meiosis in fungal reproduction?

It occurs in sexual reproduction across all fungal phyla except Deuteromycota.

What are sexual spores in fungi?

Spores formed when compatible nuclei unite by fusing their hyphae, resulting in ascospores, zygospores, and basidiospores.

What is the classification of fungi based on?

Their mode of sexual reproduction or molecular data.

What are the major phyla of fungi?

Chytridiomycota, Glomeromycota, Zygomycota, Ascomycota, and Basidiomycota.

What is Deuteromycota?

An informal group of unrelated fungi that reproduce strictly asexually.

What are chytrids?

Fungi in the phylum Chytridiomycota, known as the simplest and most primitive true fungi.

What is a unique feature of chytrids?

They produce zoospores capable of active movement through water with a single flagellum.

Where do chytrids typically live?

In aquatic environments, though some species can be found on land.

What are zygomycetes?

Fungi in the phylum Zygomycota that produce sexual spores called zygospores and asexual sporangiospores.

What is an example of a zygomycete?

Rhizopus stolonifer, commonly known as black bread mold.

What is the ecological role of some chytrids?

Some thrive as parasites on plants, insects, or amphibians, while others are saprobes.

What is the common name for Rhizopus stolonifer?

Bread mold.

What is the significance of the hyphae in fungi?

Hyphae are the filamentous structures that make up the mycelium and are involved in nutrient absorption and reproduction.

What is Rhizopus commonly known as?

It is the familiar bread mold.

What special structures do Rhizopus use to anchor themselves?

Rhizoids.

What industrial products are derived from Rhizopus?

Steroids, meat tenderizers, industrial chemicals, and certain coloring agents.

What is Ascomycota commonly known as?

Sac fungi or ascomycetes.

What type of spores do Ascomycota produce?

Sexual spores called ascospores, enclosed in a sac-like structure called an ascus.

What is the significance of Saccharomyces in Ascomycota?

It is used in baking, brewing, and wine fermentation.

Name two gourmet delicacies associated with Ascomycota.

Truffles and morels.

What is Aspergillus oryzae used for?

In the fermentation of rice to produce sake.

What are the main reproductive methods of Basidiomycota?

Sexual reproduction through basidiospores and asexual reproduction by budding, fragmentation, or conidia formation.

What are common examples of Basidiomycota?

Common mushrooms like Agaricus, shelf fungus, smuts, and rusts.

What is Ustilago maydis known for?

It is a maize pathogen.

What disease does Cryptococcus neoformans cause?

Respiratory illness and meningitis.

What is the significance of Amanita mushrooms?

They are poisonous to humans.

What is Glomeromycota known for?

It comprises fungi that form arbuscular mycorrhizae in close association with tree roots.

What is the mutual benefit in the relationship between Glomeromycota and plants?

Plants supply carbohydrates to the fungus, while the fungus supplies essential minerals from the soil.

What distinguishes Deuteromycota from other fungi?

They lack a known sexual cycle and are referred to as 'imperfect fungi'.

What is a common example of an imperfect fungus?

Aspergillus niger, commonly found as a food contaminant.

What are lichens formed from?

A symbiotic relationship between algae or cyanobacteria and fungi.

What role do lichens play in ecosystems?

They are key in soil formation and biological succession.

Where can lichens grow?

On bare soil, rocks, tree bark, wood, shells, barnacles, and leaves.

What economic importance do fungi have in medicine?

Many species produce metabolites that are sources of pharmacologically active drugs.

What is penicillin G and what is it produced from?

Penicillin G is an antibiotic produced by the fungus Penicillium chrysogenum.

What are some other antibiotics produced by fungi?

Other antibiotics include ciclosporin (an immunosuppressant), and fusidic acid (used to control infections from methicillin-resistant Staphylococcus aureus).

Name three medicinal mushrooms with a documented history of use.

Agaricus subrufescens, Ganoderma lucidum, and Ophiocordyceps sinensis.

What is lentinan and in which mushroom is it found?

Lentinan is a clinical drug approved for cancer treatments, found in the shiitake mushroom.

How have fungi been used in food production?

Fungi are used as a direct source of food (mushrooms and truffles), as a leavening agent for bread, and in the fermentation of products like wine, beer, and soy sauce.

What are some commonly eaten species of mushrooms?

Commonly eaten species include Agaricus bisporus, straw mushrooms (Volvariella volvacea), oyster mushrooms (Pleurotus ostreatus), shiitakes (Lentinula edodes), and enokitake (Flammulina spp.).

What role do fungi play in bioremediation?

Certain fungi, especially 'white rot' fungi, can degrade pollutants like insecticides and heavy fuels, converting them into carbon dioxide, water, and basic elements.

What industrial chemicals are produced by fungi?

Fungi are used to produce citric, gluconic, lactic, and malic acids, as well as industrial enzymes like lipases and cellulases.

What are Psilocybin mushrooms known for?

Psilocybin mushrooms, also known as magic mushrooms, are ingested for their psychedelic properties.

What is a significant fungal pathogen affecting cultivated plants?

The rice blast fungus Magnaporthe oryzae causes extensive damage to agriculture.

What are mycoses and how are they classified?

Mycoses are fungal infections classified as superficial, cutaneous, subcutaneous, or systemic, based on tissue involvement and host response.

What are superficial mycoses and where do they commonly occur?

Superficial mycoses, or tineas, mostly occur in the tropics and affect the outer surface of hair and skin.

What fungus causes black piedra?

Piedraia hortae causes black piedra, characterized by brown/black nodules on the scalp hair.

What is white piedra and which fungus causes it?

White piedra is a superficial infection caused by Trichosporon cutaneum.

What types of fungi cause cutaneous mycoses?

Cutaneous mycoses are caused by fungi from the genera Microsporum, Trichophyton, and Epidermophyton.

How do cutaneous mycoses affect the skin?

These fungi grow above where keratin is deposited, causing irritation and inflammation of underlying epithelial cells.

What is the significance of keratin in cutaneous mycoses?

Keratin is a protein that these fungi can degrade, leading to irritation and allergic reactions in the host.

What are the characteristics of superficial mycoses?

Superficial mycoses are restricted to the outer layers of hair and skin and are often less severe than deeper infections.

What are the potential consequences of untreated fungal diseases in immunocompromised individuals?

Untreated fungal diseases can be fatal for individuals with immunodeficiencies.

What is the role of fungi in fermentation?

Fungi are essential in fermentation processes for producing various food products, including alcoholic beverages.

What is the relationship between fungi and heavy metals?

Fungi can biomineralize uranium oxides, indicating potential for bioremediation of radioactive sites.

What are the effects of cutaneous fungi on epithelial cells?

Cutaneous fungi can cause allergic reactions leading to the death of epithelial cells.

What are the implications of using fungi in traditional medicine?

Fungi have a long history of use in folk medicine, particularly in Traditional Chinese medicine.

What are subcutaneous mycoses and how do they typically occur?

Subcutaneous mycoses are infections caused by fungi that are saprotrophic inhabitants of soil, particularly in tropical and subtropical regions. They become infective when introduced through wounds in the skin, often affecting individuals who walk barefoot.

What fungi are responsible for human mycetoma, and what are its characteristics?

Madurella mycetomatis and M. grisea (filamentous, Ascomycota) cause human mycetoma, also known as madura foot. It results in localized tumor-like abscesses, chronic inflammation, swelling, distortion, and ulceration of the infected area. Mycetomas are resistant to chemotherapy, often requiring surgery or amputation.

What disease is caused by Sporothrix schenckii and how does it spread?

Sporothrix schenckii causes sporotrichosis, also known as 'rose handler's disease.' It enters through minor skin injuries and can spread through the lymphatic system, potentially leading to infections in the lungs, bones, joints, and causing conditions like endophthalmitis, meningitis, and invasive sinusitis.

What are systemic mycoses and how are they categorized?

Systemic mycoses are infections that affect the whole body, categorized into those caused by primary virulent pathogens, which can infect normal hosts, and opportunistic pathogens, which cause disease in individuals with compromised immune systems.

How do primary and opportunistic fungal pathogens typically gain access to the host?

Primary deep pathogens usually gain access via the respiratory tract, while opportunistic fungi can invade through the respiratory tract, alimentary tract, or intravascular devices.

Name some primary systemic fungal pathogens.

Primary systemic fungal pathogens include Coccidioides immitis, Histoplasma capsulatum, Blastomyces dermatitidis, and Paracoccidioides brasiliensis.

What are some examples of opportunistic fungal pathogens?

Opportunistic fungal pathogens include Cryptococcus neoformans, Candida, Aspergillus spp., Penicillium marneffei, Zygomycetes, Trichosporon beigelii, and Fusarium spp.

What types of infections do dermatophytic and keratinophilic fungi cause?

Dermatophytic and keratinophilic fungi can attack the eyes, nails, hair, and skin, causing local infections such as ringworm (trichophyton) and athlete's foot.

How can fungi cause allergic reactions?

Fungal spores can evoke allergic reactions, and fungi from different taxonomic groups can contribute to allergies.

What are mycotoxins and what effects can they have on humans?

Mycotoxins are toxic compounds produced by some mushroom species, causing effects ranging from mild digestive issues and allergic reactions to severe organ failures and death.