Lab Report On The Bacteria

The following tests according to the lab manual were performed: gram stain, fermentation tubes, methyl red, vogues proskauer, sulfur, indole, motility and growing it up on MacConkey agar. The gram stain was performed incorrectly the first time. This is because the decolorizer was not on the bacterium slide for long enough, giving a false outcome.

In the beginning of lab, we were advised to obtain a nutrient agar petri plate, which is used for the cultivation of microbes supporting growth of non-fastidious organisms. Since it contains many nutrients, a wide variety of bacteria and fungi can grow. Taking the plate,

3. Microbiologists employee a number of approached to acquiring a pure culture from a from sample containing a number of different types of bacteria. Briefly describe three different procedures commonly used to secure pure cultures from a mixed culture. The use of simple labeled diagrams may be quite helpful.

Place a small drop of sterile media onto a microscope slide. Take a small sample of the bacteria from the colony using your inoculating loop. It is important that you use asceptic technique when sampling the bacteria as you will be looking at a pure bacterial sample. Flame your inoculating loop as shown by the instructor and allow the loop to cool without waving the loop it the air. When you sample the bacteria make

2) Record the shape of the bacteria, the arrangement of the bacteria, and the gram staining characteristics.

Purpose: The purpose of this lab is to help you become a little familiar with some of the tests that can be typically performed in a clinical or research lab facility. These tests may help in determining a particular pathogen’s growth needs.

The first method is the pyrogallic acid technique in a solid medium. This technique uses streak cultures on nutrient agar slants. A person pushes a cotton plug into the tube until it almost touches the slant. The space above the cotton gets filled with pyrogallic acid crystals and put sodium hydroxide in there as well. Insert the stopper very tightly and then invert and incubate. The chemicals absorb the oxygen which produces an anaerobic environment. The second method is the shake-culture method in a solid medium. This is a molten and cooled nutrient agar which is inoculated with a loopful of an organism. The tube gets shaken, cooled quickly, and then incubated. The position of growth in the tube makes it the index of gaseous requirements for an organism. The third method os the Paraffin plug technique in a broth medium. It is a medium that has reducing substances like cystein or ascorbic acid in it. This medium gets heated to make the oxygen go away then get quickly cooled and inoculated with a loopful of culture. After that it get immediately sealed with melted paraffin and then gets incubated. The last method is fluid thioglycollate in a broth medium. It is present in redox potential indicator like resazurin, which produces a pink color in an oxidized

Make sure to sterilize the loop between each disk placement. To do this, dip into alcohol and then hold it over the Bunsen burner flame for at least ten seconds. To secure its place onto the agar, tap the disk lightly into the agar.

pneumoniae is Gram positive or Gram negative by following the staining process. A clean slide was retrieved and carefully a small drop of water was placed on the slide. The lid of the plate was opened and a sterile swab was swiped a few times to get enough of the S. pneumoniae. The swab of S. pneumoniae was mixed with the water on the slide, then allowed to air dry. After air drying, the slide were held with slide clamps and passed over a Bunsen burner at a 45° angle a few times until warmed. The slide was placed on the staining tray that was set up prior to the beginning of the lab. Four drops of crystal violet were dripped on to the slide and left on for one minute. Then the slide was tilted at a 45°angle and carefully the crystal violet was washed off with the distilled water from the squirt bottle. Next, the slide was stained with iodine and kept on for one minute. Then the slide was tilted at a 45° angle and washed off carefully with distilled water from squirt bottle. 95% alcohol was dripped onto the slide until the run off became clear. Distilled water from squirt bottle was used to wash off the 95% alcohol. Safranin was applied for 45 seconds, then the slide was tilted at a 45° angle and washed off with distilled water. With bibulous paper, the slide was carefully dried to prevent removing of S. pneumoniae and ruining the

For this particular assignment, I was given an unknown bacteria from my lab instructor and several procedures were performed to identify the unknown bacteria. The first procedure was completing a quadrant streak on a tryptic soy agar (TSA) plate. The purpose of streaking is to isolate single colonies or colony forming units (CFU). My inoculating loop was placed into the fire of a Bunsen burner to ensure that no other bacteria were present and allowed to cool. Next the inoculating loop was placed into the TSB of the unknown bacteria and in Quadrant I I swiped from left to right from top to bottom. After flaming my inoculating loop once again, I took my loop and from the bottom of Quadrant I, and I took the bottom part of the streak and swiped

For both agar plates, a spread plate was created by using a cotton bud dipped into a liquid suspension of the bacteria followed by a wiping of the entire surface

The agar plates will be divided into 3 sections (one for each filter paper discs) using any form or marker. Using sterilized forceps, put the filter paper disc at the center of each area in an agar plate. Apply 20µl of each concentration for 10 agar plates. This includes distilled water (negative control), 100% ethanol and the common antibiotic. Observe for the zone of inhibition within 16 hours and above (Tendencia, 2004). To measure the zones of inhibition, use a ruler and record the diameter in terms of millimeters.

Nutrient Broth and Nutrient Agar were used to inoculate bacteria taken from different surfaces. Nutrient agar plate was inoculated with a sample taken from skin surface. A sterile cotton swab was first immersed on sterile water, then, rubbed against the skin with swirling motion and transferred to an agar plate by rubbing

Used a fresh pipette tip for each sample and dispensed 10.0 µL of DNA ladder (M), 10.0 µL of R-, and 10.0 µL of R+ into designated wells.

With a glass-marking pen preferably black, mark four sterile test tubes. The test tubes should be marked 1A, 2A, 3A, and 4A. First, using a mortar and pestle to grind together a spatula of sand, a 0.5 cm pieces of apple, and 1 ml of distilled water. Then pour this mixture into test tube 1A. Second, using a mortar and pestle to grind together a spatula of sand, a 0.5 cm pieces of potato, and 1 ml of distilled water. Then pour this mixture into test tube 2A. Third, using a mortar and