Microbiology Lab 7: Bacteriophage, Microbial Diversity, and Eukaryotic Microorganisms

What are bacteriophages?

Viruses that specifically infect bacterial cells.

What is the purpose of the lab?

To determine how viruses are restricted to certain hosts and to explore microbial diversity.

What types of microorganisms will be explored in this lab?

Eukaryotic microorganisms, specifically protists, fungi, and helminths.

What is the host bacteria used for growing bacteriophages in this lab?

Escherichia coli.

What is a plaque in the context of bacteriophage activity?

A zone of clearing on agar caused by the lysis of bacteria infected by bacteriophages.

What is the significance of the dilution series in the experiment?

To prepare different concentrations of bacteriophage for infection of E. coli.

What is the initial concentration of the bacteriophage used in the dilution?

10^7 PFU/mL (plaque forming units/mL).

What temperature is used to incubate the agar plates after solidification?

37°C for 2 days.

What materials are needed for the bacteriophage activity?

Sterile saline tubes, soft agar, agar plates, sterile pipets, bacteriophage, and E. coli.

What should be recorded after examining plaques?

The typical morphology of plaques, including size and shape.

What types of eukaryotic microorganisms are required to be observed in Activity 2?

One fungal species, at least three protozoa species, and at least three helminths.

Why is it important to pay attention to working distance when observing slides?

Some slides have thick coverslips that limit the use of higher magnifications.

What is the first step in preparing the plates for bacteriophage infection?

Combine 100 µl of diluted phage with 300 µl of E. coli.

What is the role of the soft agar in the experiment?

To solidify and support the growth of bacteria and bacteriophages on the agar plates.

What should be done after pouring the soft agar mixture onto the TSA plate?

Slide the plate in a circular motion to spread the agar uniformly.

What is the purpose of comparing results with others in the group?

To validate findings and ensure accuracy in counting plaques.

What is the significance of the plaques formed by bacteriophages?

They indicate successful infection and lysis of bacterial cells by the bacteriophage.

What is the expected outcome of the bacteriophage activity?

The formation of visible plaques on agar plates after incubation.

What should be done with the pipet after transferring the bacteriophage?

Discard the pipet to avoid contamination.

What is the main focus of the microbial diversity section of the lab?

To observe various life cycle stages of eukaryotic pathogens.

What is the first step in the serial dilution process?

Label the tubes containing 0.9 ml of sterile saline for the dilution series.