Microbiogy Labs 5+7 - Algae, Protozoa, Fungi

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Algae Characteristics

Eukarya - Protist

Most single-celled

Photosynthetic

Aquatic

Diatoms (Algae)

Volvox (Algae)

Spirogyra (Algae)

Ceratium (Algae)

Protozoa Characteristics

“First Animal”

Eukarya - Protist

Unicellular, heterotrophic

Classified by movement

Protozoa Movement

Pseudopodia

Cilia

Flagella

Apicomplexa (nonmotile parasites)

Protozoa stages (names)

Trophozoite

Cyst

First stage protozoa

Trophozoite

Active feeding state

Second stage protozoa

Some can form cysts

Like an endospore for protozoa

Protects from harsh conditions

Call allow a parasite to live outside a host

Allows for transfer from host to host

Amoeba proteus (Protozoa)

Amorphous

Moves by pseudopods

Free-living (non-parasitic)

Freshwater organism

Entamoeba coli (Protozoa)

Non-pathogenic

Colonizes human GI tract

Cyst has 8-16 nuclei

Moves via pseudopodia

Balantidium coli (Protozoa)

Causes balantidiasis (most asymptomatic but can be diarrhea)

Fecal-oral transmission, or contaminated food/water

Cysts withstand acidic pH of stomach

Excystation occurs in GI tract

Trophozoite causes ulceration of the colon

Highly motile (ciliated) trophozoite

Giardia lamblia (Protozoa)

Flagellated

Causes giardiasis

Same life cycle as B. coli

Attaches to epithelium in duodenum via ventral sucking disks

Cysts are shed via feces

Most infections are asymptomatic

Infects a number of mammals (dogs, humans, beavers..)

Trichomonas vaginalis (Protozoa)

Causes trichomoniasis (vulvovaginitis), curable STI found in both sexes

Most infections asymptomatic

Four anterior flagella

Trophozoite only; no cyst stage

Trypanosoma cruzi (Protozoa)

Flagellated - no cyst

Causes Chagas

Endemic throughout Latin America and South America

Insect vector - Acquired through the reduviid (kissing) bug

Infection can be lifelong, most asymptomatic

Can cause heart problems (dilated heart, arhythmia)

Plasmodium vivax (Protozoa)

Causes malaria

Insect vector

Life cycle involves insect (female Anopheles mosquito) and vertebrate tissue

Nonmotile - apicomplexa

Fungi Characteristics

Eukarya - Fungi

Nonmotile

Cell wall made from chitin (polysaccharide)

Absorptive heterotrophs (secrete enzymes, then absorb nutrients)

Saprophytes (decompose decaying matter)

Fungi divided by

Unicellular yeasts

Filamentous molds

Based on appearance

Fungi parts

Hypha (plural: hyphae)

• Individual fungal filament

Mycelium

• Fibrous network of hyphae

Microscope techniques for fungi

Tape mount

Slide culture

Tape mount

Lactophenol Cotton Blue (LPCB) –

• Lactic acid - preserves fungal structures –

• Phenol – kills any live organisms

• Cotton Blue – stains chitin

Advantages –

• Fast/easy to prepare

• Slide lasts long time

Disadvantages

• Structures may not be preserved

Slide Culture

Potato Dextrose Agar (pH 5.5 – Fungi like acidic environment)

Best grown at RT, dark, and moist

Advantages

• Fungal structures preserved

Disadvantages

• Takes days to grow

Saccharomyces cerevisiae (Fungi)

Common baker’s yeast

Does not form mycelium (not fuzzy)

Produces colonies that look like bacteria

Rhizopus (Fungi Mold)

“bread mold”

White or grayish cottony growth

Mycelium appears white

Sporangia (where spores are) appears black

Aspergillus (Fungi Mold)

Characterized by green-yellow or brown colonies with white edge

Conidiospores (asexually produced fungal spores)

Penicillium (Fungi Mold)

Conidiospores (asexually produced fungal spores)

Fungal spores - asexual reproduction

Offspring identical to parents

Sporangiospores

• Found in Rhizopus

Conidiospores

• Found in Penicillium and Aspergillus

Fungal spores - sexual reproduction

Offspring genetically different

Zygospores

• Found in Rhizopus

• Fusion of nuclei occurs in zygospore

Candida albicans (Fungi)

Grows as yeast and filamentous fungi

Part of gut flora

Causes candidiasis

Schizosaccharomyces (Fungi)

Look for 8 spores

Produced by meiosis