Microbiology Chapter 5

photosynthetic eukaryotic organisms; classified as a Protistas in the Five Kingdom System of Classification along w/protozoa;

phycology/algology
studied by phycologist/algologist

All cells have: cytoplasm, cell wall (usually), cell membrane, nucleus, plastids, ribosomes, mitochondria, and Golgi bodies
-Some may also include: pellicle, stigma/eyespot, flagella
They are NOT plants but are more plantlike than protozoa. (they lack a true root, stem and leafs)

-size varies from small unicellular microscopic organisms to large multicellular seaweed (NOT all algae are microorganisms)
-may be arranged in colonies or strands; in salt or freshwater, soil, and wet rocks
-produce energy from photosynthesis
-most algal cell wall contain cellulose
-They can be called green, red, golden, or brown algae depending on the pigments.
(photosynthetic protists are classified as algae in the book)

tiny unicellular algae that live in freshwater & seawater
-important members of phytoplankton
-contain silicon dioxide (glass) in their cell wall
-Together they form diatomaceous earth that can be used for filtration, insulation, and abrasives.

microscopic unicellular flagellated photosynthetic algae
-important phytoplanktons
-may produce light, therefore known as fire algae
-responsible for “red tide”

1) Desmids: unicellular/resemble a microscopic banana
2) Spirogyra: filamentous algae/produce long green strands
3) Chlamydomonas: unicellular/ biflagellated w/ one chloroplast & a stigma
4) Volvox: multicellular, biflagellated/form hollow sphere (sometimes called a colony)
5) Euglena: has both algae & protozoan features/has chloroplast & is photosynthetic (stores energy as starch)

Euglena

YES

ALGAE…PROTOZOA

nearly 50% oil (being studied as a source of biofuel)
-agar is from a polysaccharide from red algae
-they can clog up filters and pipes

rare cause of human disease
-produces a small subcutaneous lesion (crusty looking)
-If it enters the lymphatics it can be debilitating/fatal infection
Other algae can secrete phycotoxin which can be poisonous to humans, fish, and other animals

-Eukaryotic organisms along w/ algae
-Protozoology: the study of protozoans by a protozoologist
-most are unicellular; free living organisms found in soil & water
-more animal-like than plantlike
-no cell wall, but some have pellicle; no chlorophyll (cannot make their own food), some have a cytostome to engulf
-contractile vacuole: pumps water out of the cell

1) Paramecium: pellicle, a cytostome, & contractile vacuole
2) Vorticella spp.: contractile stalk

1) Trophozoite: motile, feeding, dividing stage
2) Cyst: nonmotile, dormant, survival stage (similar to bacterial spores)

-when they break down & absorb nutrients from the host’s body
-many are pathogens
-Ex: malaria, giardiasis, African sleeping sickness, & amebic dysentery.

-Other co-exist w/ the host in which both organisms benefit from the relationship
-ex: is termite and intestinal protozoa

-according to locomotion
1) Amebae: move by cytoplasmic extensions called pseudopodia
2) Ciliates: move by large # of hairlike cilia
3) Flagellates: move in wavelike motion
4) Sporozoa: nonmotile protozoa (ex: Plasimodium spp. which causes malaria)

Balantidium coli

-have their own kingdom; study of fungi is called mycology by a mycologist
-found almost everywhere
(saprophytic fungi: living in organic matter in water & soil; parasitic fungi: living in and on animals and plants)
-some are harmful while others are beneficial
-Eukaryotic organisms that include: yeast, moulds, and mushrooms.

TRUE

NO, but they contain a polysaccharide called chitin instead

-most are unicellular, but some grow as filaments known as hyphae, which intertwines to form a mass known as mycelium/thallus.
-Some have septate hyphae while others have aseptate hyphae

eukaryotic…prokaryotic

unicellular…multinucleated

-species specific & can be done by: budding, hyphal extension, or spore formation
The 2 general categories of fungal spores are: sexual or asexual (conidia) spores
1) sexual: produced by fusion of 2 gametes (name depends on manner they’re formed)
2) asexual: not made by fusion of gametes
some can produce both types

Currently divided by 5 phyla; depending on the mode of sexual reproduction
“Lower fungi”:
-chytridiomycotina: live in water and soil
-zygomycotina: food spoilage, such as bread mould
“Higher fungi”:
-Ascomycotina: yeast & some fungi that cause plant disease
-Basidiomycotina: includes yeast & “fleshy fungi” that live in the woods (mushroom, toadstool, bracket fungi & puffballs)
Last phylum:
Deuteromycotina: fungi w/ no known mode of sexual reproduction

-unicellular eukaryotes that lack mycelia
-individual cells are known as blasopores (can only be seen w/ microscope) (usually produced by budding)
-pseudohypha: string of elongated buds from a yeast (resembles a hypha but it is NOT one)
-some produce a sporelike structure known as chlamydospores, which are found in soil, water, & skin of fruits and vegetables

Saccharomyces cerevisiae: baker’s yeast
-Anaerobic condition: sugar->alcohol
-aerobic condition: simple sugar-> CO2 & H2O
Good source of nutrients b/c it produces vitamins/proteins. Colonies look similar to those from bacteria, wet mounts can be used to differentiate the two.

Mould

-grow as cytoplasmic filaments or hyphae that make mycelium
(growing above the surface-aerial hyphae, reproductive hypha; growing below the surface-vegetative hyphae)
-Phytophthora infestans caused potato blight in Ireland mid-19th century.
-Many are important in antibiotic production (penicillium & Acremonium)
-some molds are used to produce large quantities of enzymes, citric acid, & other organic acids

-large fungi that are encountered in the forest which are not microorganisms
-mushrooms, bracket fungi, toadstool, and puffballs
-Mushrooms are a class of true fungi; contains a network of filaments or strands (mycelium) that grow in the soil along w/ a fruiting body that makes spores; some are good and some deadly

Yeast, mold, and some fleshy fungi can cause disease in animals, plants or humans.
-Fungi can destroy plants as well as release mycotoxins. Infectious diseases caused by fungi are called mycoses.
Categories include: superficial, cutaneous, subcutaneous, and systemic

fungal infection of the outermost area of the human body (ex: nails, hair, epidermis)

fungal infection of the living layers of the skin(dermis)
-Dermatophytes cause tinea, infection known as “ringworm”
-C. albicans is an opportunistic yeast that lives on the skin and mucous membrane, that may invade the bloodstream becoming systemic

fungal infection of the dermis and underlying tissue
(ex: Madura foot)

fungal infection of the internal organ(s)
-spores from pathogenic fungi can be inhaled causing respiratory infections- ex: blastomycosis from wood & leafs

sent to mycology section of clinical microbio lab
-Yeast are identified through biochemical test
-Moulds do not use biochemical test instead there is a combination of microscopic observations and the growth speed.
-Skin test may be available for certain types of mycoses
Most effectively treated w/ antifungals
(Nystatin, amphotericin B, 5-fluotocytosine; but can be toxic to humans)

can live either as yeast OR moulds…depends on growth conditions, known as dimorphism.
-Unicellular yeast: grow at body temp (37 deg. C)
-Moulds: grow at 25 deg. C

-a combination of two organisms in a symbiotic relationship
-Algae or cyanobacteria= Photobiont
-Fungus=mycobiont
-They are NOT associated w/human disease

found in soil & rotting wood (not known to cause human diseases)
have protozoan & fungal characteristics
-Cellular slime molds: start life as independent amebae (food-> motile/multicellular slug-> fruiting w/ a stalk & spore cap->spores from the cap->amoeba
-Plasmodial/acellular slime moulds: produce stalks & spores (haploid cells fuse-> diploid cells->large masses of motile multinucleated protoplasm. Each mass is known as a plasmodium.)

d) all of the above

d) sporozoa

b) paramecium

c) hyphae

d) pellicle

c) sexual and asexual

d) an alga and a fungus

a) light-sensing organelle

d) yeast

d) Prototheca