General Microbiology Ch5 pt2

What are the two types of fungi?

Hyphae and Yeast

Hyphae

Type of fungi that consists of long filamentous cells that make up molds

Yeast

Type of fungi with round/ovoid shape

How to yeasts reproduce?

Budding (small swellings on the surface of the cell that eventually become separate cells

What is one defining feature of yeasts?

Have cell walls and lack motility appendages

What do hyphae sometimes look like?

Soft, velvety, and have a cotton-like appearance

Mycelium

Woven, intertwining mass of hyphae

What are the two phases of hyphae?

Vegetative - digest and absorb nutrients

Reproductive- produce spores for reproduction

Is spore production sexual or asexual?

Can be both

Sporangium

Structure that contains many spores; similar to an egg sac

How do fungi absorb nutrients?

They secrete digestive enzymes outside of the cell wall, then absorb the simple nutrients; rather than digesting internallly

What are the majority of fungi?

Saprobes

Saprobes

Living off dead plants and animals

What is another type of fungi (nutrition wise)?

Parasites

Mycoses

Fungal infections

Opportunistic Pathogens

Only cause infection in people whose immune systems or defenses are compromised

Pneumocystis jirovecii pneumonia

Frequent most opportunistic infection seen in AIDS patients

Fungal Meningitis Outbreak 2013

Lab making pharmaceutical pain management drugs was not up to cleanliness standard and shipped medication out that was contaminated with fungal spores

Benefits of fungi

Antibiotics, organic acids, vitamins

Fermentation

Decomposers

Making foods and in genetic studies

What are the two types of protists?

Algae and Protozoa

Algae

Photosynthetic organisms found in fresh and marine waters

Contain chlororplasts

Contribute to food webs and oxygen levels

Micro and Macroscopic

Sexual and Asexual

Cell wall present; may or may not have flagella

Not typically pathogenic

Dinoflagellates

Deadly red algae that release a neurotoxin

High fatality rate

Shellfish are able to absorb neurotoxin and not die

Protozoa

Diverse group of single-celled organisms that include 65,000 different species

Most are harmless and free living **some pathogenic

Vary in shape and lack cell wall

Most have locomotor structures

Exhibit sexual or asexual reproduction

How are protozoans classified?

By their locomotor structures

Mastigophorans

Flagellated

Amoebas

Pseudopod-bearing

Ciliophorans

Ciliated

Apicomplexans

No motility appendages

How do amoeba feed?

Endocytosis; feed on bacteria, algae, or dead plants/animals

Endocytosis

Engulfing substances into the cell

What are the two phases of a protozoa?

Trophozoite and Cyst

Trophozoite

Motile feeding stage

Cyst

Dormant stage entered during unfavorable conditions

(similar to endospore, but not that resilient)

Trypanosoma cruzi

Pathogenic, flagellated protozoan

Transmitted by blood sucking reduviid bug (aka kissing bug)

Causes Chaga’s disease

Chaga’s disease

Short term: Nausea, diarrhea, headache, swollen glands, enlarged liver/spleen/colon/esophagus

Long term: Massive edema, congestive failure, cardiac arrest

How is Chaga’s disease spread?

T. cruzi reproduces in intestinal tract of reduviid bug and harbored in the bug’s feces. Bug bites host and defecates near bite. Feces containing T. cruzi enters the bite wound. Trypanosomes spread from the blood to many sites in the host, causing many symptoms.

Helminths

Multicellular worms that parasitize host tissues

About 50 species that infect humans

Distributed worldwide

Most are acquired through ingestion of larvae/eggs in food, soil, or water (Some carried by insect vectors or penetrate skin directly)

What are the three categories of helminths?

Cestatodes, Nematodes, and Trematodes

Flatworms

Incomplete digestive systems, simple excretory/nervous systems

Cestatodes (Flatworms)

Trematodes (Roundworms)

Cestatodes

Type of flatworm

Tapeworms

Long, segmented bodies

Have hooks or suckers for attaching to hosts

Trematodes

Type of flatworm

Flukes

Flattened, non-segmented worms

Have sucking mouthparts

Nematodes

NOT a type of flatworm

Roundworms

Cylindrical, non-segmented bodies

Have a complete digestive tract and secretory system

Spines or hooks on mouth

How do helminths reproduce?

Most undergo sexual reproduction

Nematodes have separate sexes

Trematodes and Cestodes are hermaphrodites

Hermaphroditic

Containing both male and female parts

Tapeworms

Continue to grow until death; eggs pass in feces

Taenia solium (“Pork Tapeworm”)

1. Humans consume undercooked pork containing tapeworm cysts

2. Larvae emerge and attach to intestinal wall

3. Tapeworm matures in intestines and produces a long series of reproductive segments

4. Proglottids are shed from end of worm and passed in feces

5. Pig eats food contaminated by human feces

6. Larvae hatch in pig intestine and migrate via blood vessels to muscle tissue

7. Larvae form cysts in muscle tissue

True/False: Cysts get destroyed with proper internal cooking temp

True