First Day! Streak Method, Gram Stain Test and Microscope.



First day in the STEM-TRAIN program. I learned about the “Streak Plate Method”, the “Gram Stain Test” and how to use a microscope. (Sept. 10th, 2019)

V-Fisheri bacteria

At the beginning of the class, Shawn, a senior student, explained to me the experiment he was working on. He was working with V-fisheri bacteria that have as bioluminescent properties. The goal of his experiment is to find some components that can stop the bacteria from releasing AHL molecules.

  • The V-fischeri bacteria is a gram-negative bacterium found in marine environments
  • When it multiplies and it is ready to communicate with each other, it releases QS molecules.
  • When these molecules are released, the biofilm glows.
  • If the biofilm doesn’t glow there is “something” that stops the communication among these bacteria

Pathogenic bacteria also release molecules when it tries to communicate with the others; however, these molecules are toxins. The V-fisheri experiment is successful, it can be applied to pathogenic bacteria.

 I didn't take a picture, but I found one on the National Science Foundation webpage that shows how the bacteria should look when it's under UV light. "Images in this webpage are allowed for educational and non-profit use"
    Colonies of the bioluminescent marine bacterium <em>Vibrio fischeri</em>


Streak plate method


 I learned how to prepare before this experiment some of the lab equipment during the experiment.
  • We used the Bunsen burner to sterilize the nozzle of the flask because most of the bacteria die at high temperatures. IMAGE 1A & IMAGE 1B
    
        IMAGE 1A
 



IMAGE 1B


IMAGE 2A

  
  • The pipette pump is placed in the Mohr Pipette, while the pipette is in the bag. (It avoids cross-contamination) Do not let the pipette touch anything.  IMAGE 2A

This is the process to put the broth media (with bacteria colonies) to a petri dish:
  • First put some of the broth in a test tube, to avoid contaminating the whole flask. 


  • Once in the test tube, use a loop to spread the bacteria into the petri dish.

Remember to sterilize the flask before putting it away for storage. 

There are multiple streaking methods to spread bacteria into the petri dish. We did the Quadrant Streak Method:
  • First, we sterilize the loop with fire and let it cool. IMAGE 2A & IMAGE 2B

             
IMAGE 2A

    IMAGE 2B

  • Then, we inserted the loop into the sample, and smear on the edge of the plate. Also, make sure of using the loop in the right way. IMAGE 3A & IMAGE 3B
       
IMAGE 3A


IMAGE 3B

  • We sterilized the loop again and made think strikes from the smear. We repeated these 4  more times. (drawing of the plate and the loop on the surface). That would be STEP 1
  • Before every other group of strikes is made: sterilized the loop, let it cool, and then strike thin lines.
  • When you're finished, type both sides of the petri dish and incubate it. 

                       Remember to sterilize the loop before putting it away for storage. 


I found this interesting video on YouTube that helped me to understand the steaking method. It shows every step from how to light a Bunsen burner to the Petri dish's streaks.


Gram Stain Test



This test helps to differentiate between 2 large groups of bacteria based on cell wall constituent.

The test consists of coloring the peptidoglycan layer of the bacteria.

I will explain this test in another post because we have done it other times, and I didn't take a picture of my bacteria the first time (It was Gram Negative).

Microscope

When I did my first Gram Stain Test, I learned how to use a microscope for the first time. Shon taught me how to look for my bacteria, and how to clean the microscope after using it.
I feel like a video would be better explaining this because once you start using the x10, x40 and x100 lens, you have to be careful. Remember to hold the microscope with both hands!



 I know it's a lot. When I started writing this post, I realized that I learned many things in just one day. The most impressive thing is that time flies when we're in the lab. 


Comments

Post a Comment

Popular posts from this blog

Protein: Q13231 (CHIT1)

Image
This semester, I'm focusing on CHIT1.  CHIT1 is a gene and encodes a protein called Chitotriosidase-1, and is a member of the chitinase family. This is selectively expressed in activated tissue macrophages. As a biomarker  (it indicates the  severity or presence of some disease state) is the best  to monitor Gaucher disease from the three most commonly used. Also, it is a marker for macrophage activation in acute ischemic stroke. Chromosomal location  Cytogenetic Location: 1q32.1. 1q    = The long (q) arm of the chromosome 1 32.1 =  It is the position in the arm. Molecular Location: base pairs 203,216,079 to 203,229,673  Data and Picture Reference: Genetics Home Reference.  August 17th, 2020. CHIT1 gene, Chitinase1. Retrieved from: https://ghr.nlm.nih.gov/gene/CHIT1#resources Function:  Chitinases wo rks in both innate and adaptive immunity.  They are necessary for the following functions: Degrades chitin, chitotriose and...
Read more

CULTURAL INTELLIGENCE

Something that I learn about cultural intelligence and cultural responsiveness is to first have cultural openness and cultural awareness. From what I understood one has to be open to learn about other people's culture with an open mind. However, this doesn't mean to be invasive or assume somebody's cultural background.  I like the definition of  Business professors P. Christopher Earley and Elaine Mosakowski about cultural intelligence. They define it as “an outsider’s seemingly natural ability to interpret someone’s unfamiliar and ambiguous gestures the way that person’s compatriots would.”  This means to have the ability to relate to people from other cultures by empathizing and actively working to understand customs and norms of other cultures besides our own  ( What Is Cultural Intelligence and Why Is It Key to Business? – Nationwide , n.d.). Now, according to the National Center for Culturally Responsive Educational Systems (NCCREST), “cultural respons...
Read more