Week 13: Reflection

I am so THRILLED that this class is almost over and that I'm graduating. I'm glad I picked microbiology as one of my last classes in college. The information that I learned from class will help me in my future career and in maintaining proper person hygiene. The labs that we did recently really helped me gain clinical experience of what a microbiologist would do. 

The labs showed me how diseases and conditions are tested for. Recently, I developed a sore throat from hay fever yet it persisted for another week. This had me thinking if my sore throat was really from allergic reactions. If I had the equipment and materials, I would know how to test what was causing my sore throat. I would swab the back of my throat and swab it on an agar plate and incubate it. Next, I would take a sample of the growth and conduct a gram-staining test and further testing after that. Microbiology taught me this and I am glad that I could learn these techniques and facts so that I can apply them to life. 

Week 12: Definitions

Hypersensitivity: Any immune response against a foreign antigen that is exaggerated beyond the norm. 

There are four types of hypersensitivity and it's associated diseases or conditions:

• Type I Hypersensitivity
• Allergies: An immediate hypersensitivity response against an antigen. 

• Type II Hypersensitivity
• Immune Thrombocytopenic Purpura: Disease resulting when drugs bound to platelets bind antibodies and complement, causing the platelets to lyse. 

• Type III Hypersensitivity
• Glomerulonephritis: Deposition of immune complexes in the walls of the glomeruli--networks of minute blood vessels in the kidneys--that may result in kidney failure; typically caused by infection with group A Streptococcus. 

• Type IV Hypersensitivity
• Allergic Contact Dermatitis: Type of delayed hypersensitivity reaction in which chemically modified skin proteins trigger a cell-mediated immune response. 

*allergic contact dermatitis 

Week 11: Investigation

In our last class, we discussed two processes of cell destruction: apoptosis and necrosis.

Apoptosis is the body's normal process of cell destruction. Necrosis on the other hand is abnormal and is caused by genetic defects or mechanical injury. Unlike apoptosis, the necrotic process involves cell swelling and damaging cell organelles. Eventually, the cell erupts, spilling out the cell contents into the blood stream. This causes inflammation and other types of immunological affects that could lead to diseases and conditions. Apoptosis slowly shrinks the cell and its remnants undergo phagocytosis.

Week 10: Observation

I'm pretty sure I've used my piercings in my previous blogs, but they are actually pertinent to what I'm studying in my microbiology class. Recently, somebody gave me a tight hug which exerted pressure on my cartilage piercing. About three to four days after that, my piercing has been bothersome.

A couple of things occurred to my ear:

• redness
• warmth
• swelling
• pain
• itching
• bleeding
• discharge of yellow-white pus

After thinking about all of these bothersome things that happened after someone bumped into my piercing, I realized that this all consists of inflammatory responses. Inflammation is a component of the innate immune system which we are all born with. Whenever there is an infection, wound, or cut, inflammation is the body's normal response to killing whatever foreign pathogens came in contact with the location as well as to help repair whatever tissue was lost from the injury.

Week 9: Definitions

Chapter 14 - Innate Immunity

1) Innate Immunity - Resistance to pathogens conferred by barriers, chemicals, cells, and processes that remain unchanged upon subsequent infections with the same pathogens.

2) Leukocyte - White blood cell.

3) Plasma Cells - B cells that are actively fighting against exogenous antigens and secreting antibodies.

4) Phagocytes - Cells, often leukocytes, that are capable of phagocytosis (type of endocytosis in which solids are moved into the cell).

5) Differential White Blood Cell Count - Lab technique that indicates the relative numbers of leukocytes.


*red blood cells surrounding a white blood cell

Week 8: Reflection

Last week when I was studying for my microbiology exam, I took a break and went to a restaurant with my cousins for dinner. Our waiter seated us close to the kitchen door and we were able to see to food being prepared. Along with the stoves and ovens, we were able to see huge sinks and faucets that were filled with dirty dishes, utensils, and cooking pans.

Comparing the cleaning process of dishes and utensils at a restaurant and the cleaning process at home is different. In a public area, such as a restaurant, the process of killing germs and microbes is known as sanitization. In a general area, such as a sink inside your kitchen, the process of killing germs and microbes is known as disinfection.

Sanitization kills 99.9% of bacteria in under 30 seconds and must pass the Official Detergent Sanitizer Test. Disinfection kills bacteria in under 10 minutes.

Week 7: Investigation

At my internship in a pediatrician's office at Washington Adventist University, I stood in and watched the doctor perform a throat culture on a young boy. The procedure was done with a swab (a larger version of a q-tip).

The procedure is quite simple: the patient opens his or her mouth and the doctor uses a tongue depressor so that he or she can have a better view of the back of the throat. Next, the doctor takes a swab and rubs it along the back of the patient's throat for a few seconds. After the swabbing is completed, the swab is concealed in a bag and is sent to the laboratory for testing.

The purpose of swabbing is to gather the secretions created by the throat and mouth that may have bacteria or foreign pathogens. The laboratory bag serves the purpose of blocking off foreign particles that might come in contact (via direct, liquid, or air) and prevents contamination. Once the swab is sent to the lab, the technicians use the same swab and rubs it in a petri-dish to be incubated. After the incubation period, the growth in the dish will determine if there were any foreign pathogens present and if so, what type of pathogen it was.

Typical diseases that can be diagnosed by a throat swab include strep throat, tonsillitis, and pneumonia.

Week 6: Observation

These past few lab periods, we placed different antimicrobial agents in a bacteria medium. After incubating them for two weeks, the bacteria grew and was visible. The places where the antimicrobial agents were placed each had a clear circle surrounding them. Each of the agents were different and had circles of different circumferences. The size of the circumference of the circle showed which agent was the most effective in stopping bacterial growth.

Although it was clear to see no growth around the microbial agents, one must go into further detail with the antimicrobial agent to determine if it was bacteriostatic or bactericidal. Bacteriostatic refers to bacteria-inhibiting and bactericidal refers to bacteria-killing. If it was bacteriostatic, no growth would've occurred because the microbial agent inhibited growth from the beginning. If it was bactericidal, bacteria would've grown like the rest of the plate but the agent would've killed whatever was surrounding it.

Week 5: Definitions

Chapter 8: Recombinant DNA Technology

Here are three types of artificial methods to introduce DNA into cells:

Electroporation: A method that uses an electrical current to puncture microscopic holes through a cell's membrane so that DNA can enter the cell from the environment.

Protoplast Fusion: A method that exposes protoplasts to polyethylene glycol to increase the rate of fusion. The fusion of protoplasts allows the cytoplasmic membrane of both bodies to fuse to form a single cell that contains the genomes of both "parent cells."

Injection: There are two types of injection methods
a. Gene Gun: A device powered by a blank .22-caliber cartridge or compressed gas to fire tiny gold beads (covered with DNA) to a target cell.
b. Microinjection: DNA is inserted to a target cell with a glass micro-pipette having a tip diameter smaller that that of the cell or nucleus.

 
*Protoplast Fusion

Week 4: Observation

This past week in microbiology lab, we cultured different plates with certain bacteria. One method that we learned was the isolation streaking. The purpose of isolation streaking is to create isolated colonies of bacteria.

In the isolation streaking, the bacteria is collected by using a sterile inoculating loop. Once collected, the streaking occurs in four quadrants. The first quadrant contains the first contact of the inoculating loop. After the streak was made, the inoculating loop is then heated by the incinerator. After the loop in sterile again, the second quadrant is filled with the similar streak patter as the first. Instead of collecting the bacteria again from the original source, the bacteria is collected from the first quadrant by dragging the inoculating loop from the first quadrant. The same process is repeated for the third quadrant and bacteria is dragged from the second to third quadrant and the fourth quadrant has bacteria from the third quadrant's streak.

Week 3: Investigation

Different Types of Bacteria Based on Temperature Tolerance

This past week, we learned about different classifications of bacteria. One classification in particular was on which bacteria grow in certain temperature ranges. Listed below are four types of bacteria that we learned in class, in addition to an extra group:

• Psychrophiles can grow at 0° C but optimum is about 15° C.
• Psychrotrophs can grow at 0° C also but optimum is 20 - 30° C – (important in food spoilage).
• Mesophiles grow best at moderate around 37° C – (many pathogens fall in this category).
• Thermophiles have a growth optimum at around 60° C.
• Hyperthermophiles have growth optima of 80° C or higher.

Week 2: Definitions

Chapter 4: Microscopy, Staining, and Classification

Differential stains: In microscopy, a stain using more than one dye so that different structures can be distinguished. The Gram stain is the most commonly used.

Here are three examples of differential stains that we discussed in class this week:

1) Gram stain: Technique for staining microbial samples by applying a series of dyes that leave some microbes purple and others pink. Developed by Christian Gram in 1884.

2) Acid-fast stain: In microscopy, a differential stain used to penetrate waxy cell walls.

3) Endospore stain: Differential stain which stains endospore or spore bacteria (Clostridium and   Bacillis). 

 

Week 1: Reflections

I'm excited for this new semester, especially taking Microbiology. This past week in class, we learned about different people (scientists, nurses, etc.) and how they contributed to microbiology. The person that I focused on was George M. Sternberg. He was a U.S. Army General Surgeon who traveled with the U.S. army for many wars, including the Civil War. After being sick with typhoid and yellow fever, he took further interest and studied these diseases. He, along with Walter Reed, were able to find a way to stop the spread of typhoid fever and contain it. He was known as the first American Microbiologist.

I'm looking forward to this class and all the useful information that I can use later in the future.