Micro 2420 LAB HW-5
Which of the following may induce dysentery? (Mark all that apply)
- Entamoeba histolytica - Balantidium coli
Select ALL of these that are example of eukaryotic microbes. (Mark all that apply)
- Enterobius vermicularis - Trichinella spiralis - Chlamydomonas - Entamoeba histolytica
Select ALL of these that are characteristics of fungi. (Mark all that apply)
- May be unicellular or multicellular - Exhibit dimorphism, and may be a yeast or a mold depending on the environment it inhabits - May be coenocytic (mutlinucleate) or have a single nucleus per cell - May reproduce through asexual and/or sexual mechanisms
Which of the following are examples of ciliates? (Mark all that apply)
- Stentor - Balantidium coli - Paramecium
Use pseudopods for movement
Amoeba
Which image is depicting Trypanosoma cruzi, the etiolologic agent of Chaga's disease?
Answer: D Feedback: A = Paramecium caudatum, B = Amoeba proteus, C = Plasmodium falciparum, E = Giardia lamblia (cyst)
Which image is depicting Penicillum?
Answer: E Feedback: A = Aspergillus, B = Rhizopus, C = Candida albicans, D = Saccharomyces cerevisiae
Which mode of reproduction is depicted here?
Budding
Which image is depicting the causative agent of toxoplasmosis?
C
Normal human microbiota; opportunistic pathogen
Candida albicans
Use a short hair-like projections to facilitate movement
Ciliates
Dimorphic fungus that causes Valley fever
Coccocoides immitis
Yeast found in pigeon feces that may cause serious infection in immunocompromised patients
Cryptococcus neoformans
Identify the helminth shown here.
Dipylidium
Use a whip-like projection to facilitate movement
Flagellates
What is the key difference between yeast and mold?
Yeast is unicellular, while mold is multicellular
Generally, protozoans are described as ...
unicellular heterotrophic eukaryotes.
Used in food production
Saccharomyces cerevisiae
Non-motile, transmitted to new hosts through vectors
Sporozoans
Pathogenic black mold associated with poor indoor air quality
Stachybotrys chartarum
Dermatophyte associated with Tinea pedis (athletes foot)
Trichophyton
Which image is depicting the trphozoite form of Acanthamoeba?
A
Does Saccharomyces cerevisiae stain Gram-positive or Gram-negative? Research and describe the composition of yeast cell walls. How does the composition compare to the cell walls of Gram-positive or Gram-negative bacteria?
From the research, I've done S. cerevisiae cells stain both gram-positive and gram-negative. Intact, mature cells (vegetative cells) are gram-positive. Broken cells and ascospores are gram-negative. The cell wall composition of yeasts is different from that of bacterial cells. A yeast cell wall is 30-60% polysaccharides (mainly beta-glucan and mannan sugars), 15-30% proteins, and 5-20% lipids. It also has a small amount of chitin. The proteins are linked to mannan-oligo-saccharides to form mannoprotein complexes. In comparison, the cell walls of bacteria are composed of peptidoglycans of disaccharides and amino acids. Feedback: Saccharomyces cerevisiae stains Gram-positive. The cell walls of yeast, and other fungi, are made up of are made up of a layer of chitin, beta-glucan, and mannoproteins. The fungal cell wall is thick and rigid, similar to the cell wall of Gram-positive bacteria, which is why it retains the primary stain crystal violet. The Gram positive cell wall is composed of mainly peptidoglycan in addition to teichoic acids and a very small periplasm. Gram negative bacteria have a thin layer of peptidoglycan located within the periplasm. Because the Gram negatiive peptidoglycan layer is much thinner it readily decolorizes and will take on the safranin counterstain.
Dimorphic fungus found as a mold in the environment but as a yeast in the lungs once inhaled
Histoplasma capsulatum
Antibiotic source
Penicillium chrysogenum
What does this image depict?
Pseudohyphae of Saccharomyces cerevisiae
