Bio225-Chapter 12:Fungi, Algae, Protozoa, and Helminths

Eukaryotic organisms that obtain nutrients by absorption and are not photosynthetic

What are fungi?

An organism that obtains nutrients from dead or decaying organic matter

What is a saprophyte?

They secrete exoenzymes and absorb the resulting nutrients

How do fungi digest food?

A generally unicellular fungus

What is a yeast?

A fungus that grows as multicellular filaments

What is a mold?

A filament that forms part of a fungus

What is a hypha?

A network or mass of fungal hyphae

What is a mycelium?

Hyphae involved in nutrient absorption and growth

What are vegetative hyphae?

Hyphae extending above the growth surface, often bearing reproductive structures

What are aerial hyphae?

A fungus that can grow in yeast and mold forms under different conditions

What is a dimorphic fungus?

A reproductive or dispersal structure that can develop into a new fungus

What is a fungal spore?

By their reproductive structures and methods of sexual reproduction

How are many fungi grouped taxonomically?

Zygomycota, Ascomycota, Basidiomycota, and Deuteromycota (imperfect fungi)

What are the fungal groups listed in the course notes?

A fungal infection

What is a mycosis?

An infection that occurs when host defenses or normal barriers are weakened

What is an opportunistic fungal infection?

A major sterol in fungal cell membranes and a target of antifungal drugs

What is ergosterol?

it binds ergosterol and disrupts fungal membranes

How does amphotericin B act?

It inhibits ergosterol synthesis

How does fluconazole act?

Topical or mucosal fungal infections

What is nystatin commonly used for?

A diverse group of mostly unicellular eukaryotes, many associated with aquatic environments

What are protists?

By cilia, flagella, pseudopodia, or not actively moving

How can protozoa move?

A resistant or dormant stage that can help survival and transmission

What is a cyst in a protozoan life cycle?

A ciliated protozoan parasite that can cause intestinal disease

What is Balantidium coli?

Trichomoniasis, which can cause vaginitis

What disease is associated with Trichomonas vaginalis?

Contaminated water enters through the nose and the organism can invade the brain

How can Naegleria fowleri infect humans?

a harmful algal bloom that can produce toxins

What is a red tide?

Toxins associated with dinoflagellates such as Gymnodinium

What causes paralytic shellfish poisoning in the notes?

Amnesic shellfish poisoning, including exposure through clams and mussels

What is domoic acid poisoning associated with?

Fish kills and reported neurologic symptoms following certain exposures

What is Pfiesteria associated with?

Toxins associated with Gambierdiscus that accumulate in predatory fish

What causes ciguatera poisoning?

Some toxins are heat-stable

Why can cooking fail to prevent some algal toxin poisonings?

A gelling agent, including some microbiological culture media; it is obtained from red algae

What is agar used for?

Silica-containing cell walls or shells

What are diatoms known for?

A parasitic worm

What is a helminth?

Trematodes (flukes) adn cestodes (tapeworms)

What are the two major flatworm groups in the notes?

Roundworms

What are nematodes?

A host in which an immature or larval stage develops

What is an intermediate host?

A host in which a parasite reaches maturity or undergoes sexual reproduction

What is a definitive host?

By ingestion of infective eggs

How is pinworm commonly transmitted?

They penetrate the skin, enter the circulation, migrate through the lungs, are swallowed, and reach the intestine

How do hookworm larvae commonly enter the body?

Anemia from intestinal blood loss

What complication can hookworm cause?

Mebendazole

Which drugs are listed for nematode infections?

Praziquantel or niclosamide

Which drugs are listed for flatworm infections?