Week 1, Day 3

May 16, 2013

Today in lab we started with the normal procedure of donning our lab coats and washing our hands. From there we separated into our groups and retrieved our cultures from last class. Our Petri dish with our outside sample (taken from gum on a trash can), along with the samples from the rest of the groups, did not grow any cultures. We will be repeating this experiment later with fresh agar, since the agar plates seemed to be faulty.

Our streak plate, slant, and broth, that we had transferred some of our assigned sample to last lab, were all successful in growing cultures.

Petri Dish Pure Culture

Slanted Agar Culture

Broth Pure Culture

 We were able to locate many pure cultures on our streak plate and were then tasked with identifying the physical characteristics of our bacterium.

The characteristics we found in our bacterium are as follows:

• puntiform colony form;
• cream/tan pigment;
• translucent, smooth, glistening surface;
• flat elevation;
• filiform (even) on agar slant;
• no growth, sediment in broth medium.
  
  

  

  
  

  

  
  

  

  Bacteria on Culture Dish

  
  

We stored our cultures in the fridge before wiping down our benches and washing our hands. After a short break, we returned to the lab and took a new sample from outside(same gum piece from before). We placed the new sample in the incubator. We then watched as our professor prepared a bacteria culture with a T4 bacteriophage (bacteria infecting virus). The Petri dish with the added virus was placed in an incubator. Before we left the lab we cleaned our stations and washed our hands once again, leaving our lab coats behind.