Fungi

In the five kingdom system of classification, fungi are not classified as plants (kingdom Plantae) because they are ______________________________________ (i.e., lack green pigments) and have a _________________________________________ mode of nutrition.

Achlorophyllous/ chemoheterotrophic

That portion of a mold-type fungus that extends above the substrate upon which the fungus is growing (agar, soil, rotting wood, etc.) is referred to as the _____________________________ and is involved in reproduction (either sexual or asexual). The portion of the fungus that extends into the substrate is called the ________________________________ and is involved in food getting.

Aerial mycelium/ vegetative mycelium

_______________________ is the name given to a mycotoxin produced by Aspergillus flavus.

Aflatoxin

Define Aflatoxin:

Aflatoxins are a type of mycotoxin produced by fungi identified as Aspergillus flavus (A = Aspergillus, fla = flavus, toxin = toxic substance), and Aspergillus parasiticus. Aflatoxins are potent carcinogens that can cause liver cancer when ingested in high doses. Because Aspergillus are soil fungi, contamination of hay, grains and peanuts can occur when conditions favor fungus growth.

Two genera of fungi known to produce mycotoxins that can cause severe illness or death when consumed by humans are _______________________ and ___________________________.

Amanita and Aspergillus

Yeast type fungi typically reproduce asexually via a process called ______________________ during which there is uneven division of the cytoplasm, one "daughter" cell being much smaller than the other.

Budding or the formation of blastospores

Name two genera of fungi that are known to cause deep or systemic mycoses (you may include opportunistic pathogens). a) _____________________________________ b) _______________________________

Coccidioides, Histoplasma, Cryptococcus, Aspergillus, Rhizopus and Candida are common opportunistic pathogens; however, multiple other types of fungi can cause systemic mycoses in immunocompromised individuals.

Superficial fungal infections are often caused by fungi in the genera Epidermophyton, Trichophyton and Microsporum. These fungi are collectively referred to as the ___________________________ and cause a variety of infections including ________________________________________________________________________.

Dermatophytes/ tinea pedis (athletes foot) - tinea corporis/ tinea capitis (ringworm of body/ head or scalp)

Organisms in the kingdom Fungi (Myceteae) are achlorophyllous chemoheterotrophs that are made up of _________________________________ type cells, and that have cell walls containing cellulose, chitin, glucan or a combination of these polysaccharides.

Eukaryotic

Explain two ways in which fungi are considered to be of value or beneficial to humans.

Fungi are beneficial in a number of ways 1. They are saprotrophs that break down or decompose dead organic material 2. They form mycorrhizae that are beneficial to forest trees 3. They may be used as a food source, they are used in food processing/preparation (bread, cheese, wine, etc.) 4. They are a source of antibiotics 5. They are used as research tools, and are used industrially to produce enzymes, organic acids and solvents. 6. Yeast cells can also be genetically modified and used to produce human proteins.

A soil fungus in the genus _______________________________________ may cause deep or systemic infection in people with compromised immune function. These fungi typically enter the body via ____________________________________________________. (More than one answer is possible in the first blank above.)

Histoplasma, Coccidioides, Aspergillus, or Rhizopus/ respiratory tract

Define Hyphae:

Hyphae (singular = hypha), are microscopic, thread-like filaments that form the body or thallus of a mold-type or fleshy fungus. Multiple hyphae typically come together to form a mat (mycelium), that can be more or less visible to the naked eye depending on the fungus type.

The thallus of a mold-type fungus is made up of many thin thread-like filaments called ______________________________ that come together to form visible mats called mycelia. If the fungus is parasitic, and the filaments are specialized to penetrate host cells and absorb nutrients, they are referred to as _____________________________ .

Hyphae/ haustoria

Define Karyogamy:

Karyogamy is the second stage in the sexual reproductive processes of fungi (Karyon = nucleus, gamous = union or marriage). During karyogamy, two haploid nuclei (each with one set of chromosomes), join or fuse to form a diploid nucleus (with two sets of chromosomes).

Sexual reproduction as it occurs in fungi involves three stages or steps. The stage allowing nuclei to join forming a diploid zygote is called _____________________________, while the stage allowing the zygote to return to the haploid state is called ______________________.

Karyogamy/ meiosis

Matching: ____ Dermatophytes ____ Tinea corporis ____ Chromomycosis ____ Coccidioides ____ Cryptococcus ____ Histoplasma ____ Aspergillus ____ Amanita A. Soil fungus that causes San Joaquin Valley fever or desert rheumatism. B. Pathogenic fungus often associated with soil rich in bird or bat feces. C. Genus of yeast-like fungi known to be a pathogen in immunocompromised individuals. D. Recognized as the source of aflatoxin and sometimes a respiratory pathogen. E. Fleshy fungus known to produce a mycotoxin that sometimes causes fatal intoxication in humans. F. Superficial mycosis sometimes caused by fungi in the genus Epidermophyton. G. A subcutaneous mycosis caused by various pigmented fungi called black molds. H. Group of fungi known to be the cause of superficial mycoses.

Matching letter sequence is: H, F, G, A, C, B, D, and E

The thallus of a mold-type fungus is made up of many thin thread-like filaments called hyphae that come together to form a mat-like structure called a __________________________. Hyphae may be septate or aseptate; but in either case, the cells involved are all connected, and so form a true _________________________ or multinucleated mass of protoplasm.

Mycelium/ syncytium

__________________________ may be defined as the science or study of fungi.

Mycology

Define Mycology:

Mycology is the science or study of fungi or Myceteae. Microscopic fungi include molds (filamentous forms), and yeasts (single-celled forms), but in this course some fleshy fungi (mushrooms), will also be discussed.

Many types of fungi form symbiotic relationships with plant roots. Some fungi form specialized hyphae called _____________________________________ that actually help plants to absorb water and minerals (e.g., phosphorous), from the soil. These fungi are essential to forest ecosystems.

Mycorrhizae

Although some forms of fungi are the causative agents of _____________________________ (fungal induced diseases) in man and other animals, others serve as a source of __________________________________ (such as penicillin) that are used to treat disease.

Mycoses/ antibiotics

______________________________ may be defined as infections or diseases that are caused by fungi. If these diseases involve the deep tissues of the body (blood, lungs, lymphatics, etc.) they are said to be deep or _________________________________ infections and typically involve fungi that enter their host by _____________________________________________.

Mycoses/ systemic/ respiratory tract

Fungi are used industrially in the production of food, antibiotics, ___________________________, and a variety of __________________________________.

Organic acids and solvents/ enzymes (as well as other proteins)

The sexual reproductive process of fungi involves three steps or stages. The stage involving the union or joining of protoplasm is called ______________________________ while the one allowing each diploid zygote to divide into four haploid cells is called ___________________.

Plasmogamy/ meiosis

An opportunistic pathogen known to cause the formation of fungus balls in the lungs of compromised individuals is classified within the genus ________________________________.

Rhizopus

Fungi often reproduce asexually by budding, fragmentation, or by producing numerous reproductive structures called spores. If these spores are contained within a sac-like structure at the end of a filament, they are called ________________________________________.

Sporangeospores

The primary factor determining if or not an individual will be likely to develop a serious mycosis after being exposed to potentially pathogenic fungi is __________________________ ____________________________________________________________________________.

The condition of their immune system, i.e., if or not their immune system is functioning properly. People with compromised immune systems are much more susceptible to fungal infection than are normal, healthy individuals.

Define Dermatophytes:

The term dermatophyte applies to a group of fungi that cause superficial mycoses (fungal infections of the skin, hair and nail beds). Three important genera within this group are Microsporum, Trichophyton, and Epidermophyton.

Two factors that have contributed to an increase in fungal induced diseases in people living in the US during recent years are: a) __________________________________________________________________________ b) __________________________________________________________________________

There are three factors known to have caused increases in mycoses, including: 1) an increase in the widespread use of antimicrobial drugs (these tend to kill normal bacterial flora that help to keep fungus populations in check) 2) increased use of chemotherapeutic agents that damage the immune system (cancer chemotherapy and immunosuppression in association with organ transplants) 3) increases in HIV infection and the incidence of AIDS (acquired immune deficiency syndrome).