INTRODUCTION
Microorganisms such as bacteria, fungus, mold, and yeast are present and common in almost every environment on earth. The normally microscopic organisms can easily be seen using differing types of agar, which creates an ideal environment for the organisms to form colonies, which are groups of hundreds of organisms that can be seen with the naked eye. In order to see individual microorganisms, it is necessary to use the magnification of a high-powered microscope.
These techniques of microbiology are used in the following five experiments. The first experiment used Trypticase Soy Nutrient Agar (TSA), which can grow a wide variety of organisms and contains casein and soybean meal and a minute NaCl, to study the effectiveness of alcohol as a skin antiseptic. The second experiment tested the effectiveness of different kinds of mouthwashes as antiseptics using TSA as well. Experiment number three explored the normal human flora existing on skin and in nasal cavities, and two types of agar were used, including TSA and Mannitol Salt Agar, which contains manitol sugar, phenol red, and 7.5% NaCl. Mannitol Salt Agar tests for the presence of staphylococci bacteria that can survive in the salt that inhibits the growth of most other bacteria. Some forms of staph bacteria ferment mannitol and produce a yellow color around the colonies, which can easily be seen against the red background. The fourth experiment studied the number of bacteria in a diluted sample of uncooked hamburger meat using nutrient agar and a Quebec counter to count the colonies. The final experiment involved the growth of yeast cells under aerobic and anaerobic conditions.
MATERIALS
- Trypticase Soy Nutrient Agar
- Mannitol Salt Agar
- Sterile alcohol swab
- Listerine mouthwash
- Tubes of nutrient agar
- Diluted hamburger meat
- Quebec colony counter
- Apple juice
- Anaerobic yeast culture
- Hemacytometer
- Iodine
METHODS
Experiment 1. Effectiveness of alcohol as an antiseptic
1) All experiments must be done in a sterile environment; Lysol can be used to sterilize the a...
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...ide had a lot of large tan colonies and dense, small colonies. The Listerine side seemed to destroy all most all of these small colonies, but the larger colonies were actually more numerous. The other mouth washes used were salt water rinse and Scope. The salt water did almost no damage to the bacteria, and the Scope killed the most.
In experiment three, there were a lot of different kinds of organisms persent on the agar. On the plate that contained nasal micro-organisms, large yellow colonies appeared on the Mannitol Salt Agar, indicating Staphylococcus aureus. On the TSA side, small creamy white colonies were also present. These could possibly be yeast. On the plate that contained the skin swab, there was a large amount of large, fuzzy white and black growth, which is mold. There was a single light-orange colony on the TSA side, possibly a growth of Flavobacterium.
In the fourth experiment, there were a number of different kinds of colonies on the EMB plate with the meat swab. There were black dots, which indicate the presence of E-coli, pink dots, which indicate lactose-fermenters, and a few white and gray colonies.
I identified the genus and species of an unknown bacterial culture, #16, and I applied the following knowledge of morphologic, cultural and metabolic characteristics of the unknown microorganism according to the laboratory manual as well as my class notes and power point print outs. I was given an incubated agar slant labeled #16 and a rack of different tests to either examine or perform myself; the tests are as follows: Gram Stain; Nutrient Gelatin Test; Carbohydrate Fermentation; Dextrose, Lactose and Sucrose; IMVIC tests; Citrate, Indole, Mythel-Red and Vogues Proskauer test; as well as a Urease and TSI Test. Materials and Methods/Results Upon receiving the Microorganism (M.O.) #16, I prepared a slide by cleaning and drying it. Then, using a bottle of water I placed a sterile drop of water on the slide and used an inoculating loop, flame sterilized, I took a small sample of the unknown growth in my agar slant and smeared it onto the slide in a dime sized circle and then heat fixed it for ten minutes.
The first day an unknown sample was assigned to each group of students. The first test applied was a gram stain to test for gram positive or gram-negative bacteria. The morphology of the two types of bacteria was viewed under the microscope and recorded. Then the sample was put on agar plates using the quadrant streak method for isolation. There were three agar plates; one was incubated at room temperature, the second at 30 degrees Celsius, and the third at 37 degrees Celsius. By placing each plate at a different temperature optimal growth temperature can be predicted for both species of bacteria.
In this lab project, the microbiology students were given 2 unknown bacteria in a mixed broth each broth being numbered. The goal of this project is to determine the species of bacteria in the broth. They had to separate and isolate the bacteria from the mixed broth and ran numerous tests to identify the unknown bacteria. The significance of identifying an unknown bacteria is in a clinical setting. Determining the exact bacteria in order to prescribe the right treatment for the patient. This project is significant for a microbiology students because it gives necessary skills to them for future careers relating to clinical and research work.
They can be found anywhere and identifying them becomes crucial to understanding their characteristics and their effects on other living things, especially humans. Biochemical testing helps us identify the microorganism present with great accuracy. The tests used in this experiment are rudimentary but are fundamental starting points for tests used in medical labs and helps students attain a better understanding of how tests are conducted in a real lab setting. The first step in this process is to use gram-staining technique to narrow down the unknown bacteria into one of the two big domains; gram-negative and gram-positive. Once the gram type is identified, biochemical tests are conducted to narrow down the specific bacterial species.
I also inoculated a tryptic soy broth (TSB), a nutrient gelatin deep, a motility agar deep, a fluid thioglycollate medium (FTM) tube, and a TSA plate with my unknown culture. All of these inoculated media were incubated until the next class period (about 48 hours). Then when I came to class most of my inoculated tubes and my streak plate appeared to have growth. The next step I took was making a gram stain to determine the gram reaction and cellular morphology of my unknown. I used my working slant to do this, after careful examination of the gram stain, I learned that my unknown was a gram-positive bacterium. I then preceded by making a negative stain to see the size of the cells of my unknown bacteria. The cell shape was cocci and the cells occurred in clusters of tetrads. After discovering that my unknown bacteria was gram-positive cocci, I turned to page 207 of the lab manual to narrow down my options, there was only four out of the gram-positive list that were
In the last decade, the number of prescriptions for antibiotics has increases. Even though, antibiotics are helpful, an excess amount of antibiotics can be dangerous. Quite often antibiotics are wrongly prescribed to cure viruses when they are meant to target bacteria. Antibiotics are a type of medicine that is prone to kill microorganisms, or bacteria. By examining the PBS documentary Hunting the Nightmare Bacteria and the article “U.S. government taps GlaxoSmithKline for New Antibiotics” by Ben Hirschler as well as a few other articles can help depict the problem that is of doctors prescribing antibiotics wrongly or excessively, which can led to becoming harmful to the body.
The purpose of this project was to identify unknown bacteria species from a mixed culture. The two unknown species were initially plated onto Tryptic Soy Agar (TSA), Eosin Methylene Blue (EMB), Mannitol Salt Agar (MSA), and blood agar plates to distinguish between the two different bacteria using colony size, color, shape, and growth characteristics. By identifying and inoculating the differing types of colonies, the two unknown bacteria were purified and able to be tested
Inconsistencies in this lab could have caused variations in data collecting. Collecting data from one petri dish was challenging because something could have been different on other petri dishes if this experiment was tested on several petri dishes. This could have been different because the other petri dishes could have had more micro-organisms in Section 2 instead of Section 1, or no bacteria could have grown at all in every section of the petri dish.- Second, nothing grew in section B even though there were no disinfectants in that section. The reason why the bacteria and mold might have grown in sections 1, 2, and 3 was because in the process of making the experiment, the coffee filter papers were touched with glove free hands and were not clean. If this lab was run again, some changes would be to wear rubber gloves, do not pour the hand sanitizers on the coffee filter paper but just pour one pump straight into the petri dish, have more than one petri dish to collect data off of, and check when the last time someone cleaned the door knob
What are microorganisms? They are organisms that you have to view with a microscope. The three that I will be discussing are bacteria, viruses, and prions. Of the three, a bacterium is the only one that can be helpful to us in many situations, and they are also the most diverse organism on the earth. The structure, reproduction, and the diseases bacteria, viruses, and prion cause are all different. Let’s begin to compare these microorganisms.
There were five test solutions used in this experiment, water being the control, which were mixed with a yeast solution to cause fermentation. A 1ml pipetman was used to measure 1 ml of each of the test solutions and placed them in separated test tubes. The 1 ml pipetman was then used to take 1ml of the yeast solution, and placed 1ml of yeast into the five test tubes all containing 1 ml of the test solutions. A 1ml graduated pipette was placed separately in each of the test tubes and extracted 1ml of the solutions into it. Once the mixture was in the pipette, someone from the group placed a piece of parafilm securely on the open end of the pipette and upon completion removed the top part of the graduated pipette.
Molinari, J., & Hart, J. (2010). How to Choose and Use Environmental Surface Disinfectants. Cottone's Practical Infection Control in Dentistry (Third Edition ed., pp. 185- 193). Philadelphia: Wolters Kumar Lippincott Williams & Wilkins.
Microorganism is a living thing that cannot be seen by naked eye and is so small in size. Microorganism usually can be seen through microscope because microscope have the ability to see small thing using various magnification. The examples of microorganism are bacteria, fungi, protozoa, algae and virus. Among all of the microorganisms, bacteria have the greatest advantages in preserving food and beverages. Bacteria are generally harmless but can produce enzymes that can alter the structure the food. In extreme cases, bacteria can secrete toxic substances that can cause the food to spoil.
3. This freshly isolated microorganism, when inoculated into a healthy laboratory animal, should cause the same disease seen in the original animal.
Bacterial cells, like plant cells, are surrounded by a cell wall. However, bacterial cell walls are made up of polysaccharide chains linked to amino acids, while plant cell walls are made up of cellulose, which contains no amino acids. Many bacteria secrete a slimy capsule around the outside of the cell wall. The capsule provides additional protection for the cell. Many of the bacteria that cause diseases in animals are surrounded by a capsule. The capsule prevents the white blood cells and antibodies from destroying the invading bacterium. Inside the capsule and the cell wall is the cell membrane. In aerobic bacteria, the reactions of cellular respiration take place on fingerlike infoldings of the cell membrane. Ribosomes are scattered throughout the cytoplasm, and the DNA is generally found in the center of the cell. Many bacilli and spirilla have flagella, which are used for locomotion in water. A few types of bacteria that lack flagella move by gliding on a surface. However, the mechanism of this gliding motion is unknown. Most bacteria are aerobic, they require free oxygen to carry on cellular respiration. Some bacteria, called facultatibe anaerobes can live in either the presence or absence of free oxygen. They obtain energy either by aerobic respiration when oxygen is present or by fermentation when oxygen is absent. Still other bacteria cannot live in the presence of oxygen. These are called obligate anaerobes. Such bacteria obtain energy only fermentation. Through fermentation, different groups of bacteria produce a wide variety of organic compounds. Besides ethyl alcohol and lactic acid, bacterial fermentation can produce acetic acid, acetone, butyl alcohol, glycol, butyric acid, propionic acid, and methane, the main component of natural gas. Most bacteria are heterotrophic bacteria are either saprophytes or parasites. Saprophytes feed on the remains of dead plants and animals, and ordinarily do not cause disease. They release digestive enzymes onto the organic matter. The enzymes breakdown the large food molecules into smaller molecules, which are absorbed by the bacterial cells. Parasites live on or in living organisms, and may cause disease. A few types of bacteria are Autotrophic, they can synthesize the organic nutrients they require from inorganic substances. Autotrophic bacteria are either photosynthetic or Chemosynthetic. The photosynthetic bacteria contain chlorophyll that are different from the plant chlorophyll. In bacterial photosynthesis, hydrogen is obtained by the splitting of compounds other than water.
They also describe microbes as organisms that are often too small to be seen without the aid of a microscope. Microbes, also known as microorganisms, can be broken down into four classifications that are bacteria, viruses, fungi, and protozoa.