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Lab Report for Microbiology 334 exercise 3...

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Exercise 3 - Microbes in the Environment 1. Purpose : To describe why algar is used in cultured media, to prepare both a nutrient broth and agar and then compare bacterial growth on solid and liquid culture media. Describe colony morphology. Expected Results 1. In the environment sample, I suspect that the sliding door will have the most growth on the agar plate because the dor is constantly being touched and handled by different individuals 2.

I do expect turbidity in the unsterilized nutrient broth that was incubated because there is still bacteria inside the broth that will continue to grow during incubation.

3.

The nutrient agar will have more information.

Results Area Sampled : Clinical hair Incubated for: __ degree C for 7 days Estimated Diameter: 1in - .2cm Whole Colony appearance: Circular and irregular Margin: Entire Elevation: Flat and Raised (on some) Pigment: Brown, Yellow, and white Number of type: Too many Area Sampled: Slide Door Handle Incubated at ____ degree C for 7 days Estimated diameter: Spherical ones were .3in. Brown line was 1.5 in long. Rest were .1mm Whole Colony Appearance: Circular and rhizoid margin: Entire and Undulate Elevation: flat Pigment: White, black, yellowish brown Number of type: too many to count

Area Sampled: Feet Incubated for __ degree C for 7 days Estimated Diameter : .1mm - .05 inches Whole colony Appearance: White were circular. Yellow were irregular. Grey were circular

Margin: Entire and Lobate Elevation:flat Pigment: Grey, yellow, and white Number of Type: too many to count Area Sampled: Microscope lense Incubated for ___ degree C for 7 days Estimated Diameter : .05 in Whole colony Appearance: circular Margin:curled Elevation: Flat Pigment: Beige Number of Type: 10 Nutrient Broth. Area sampled was open air. incubated at 30 degree C for 7 days Non-Sterilized Broth Sterilized broth; not incubated Turbidity no no Flocculent present yes no sediment present no no pellicle present no no color yellow pale yellow tone Conclusion 1. a. Yes it did. b. yes c. yes 2. Two was the minimum number of different bacteria present which was seen by the shape and color of the bacteria on the plate 3. The non-sterilized broth had more bacterial growth due to the fact that it was not sterilized before incubating the substance. due to this, the bacteria inside was able to grow and produce during the 7 days it was untouched. However, the sterilized broth was free of contaminants and therefore had no interference between it and the liquid. 4. The door had the most bacteria and the feet had the least because the dor is handeled more often than the feet. it is constantly being exposed to different matter such as the open air where the surface the feet is constantly shield from the environment and is in warmer conditions. 5. The door had the most door bacteria where the microscope had the least because the door is constantly being handled by various people and therefore more matter gets on it than the microscope which is only being touched by two things, the eye and the hands (typically).

Questions 1. Petri plates allows you to examine species in a close, flat surface in microbiology 2. In nutrient Agar, bacteria consume sugar , or glucose . Agar allows the substance to remain solid during bacterial growth and this can allow for a higher temperature of incubation to occur without disturbing the colony you are trying to observe.

Critical Thinking 1. Gelatin can liquify at higher temperature as oppose to Agar which will not. 2. yes it did. after seeing the experiment the week after, we were able to see that bacterial growth did occur on the nutrient agar because the conditions were ideal for the bacteria t continue living. 3. you can tell if the nutrient broth was from a mixture of different microbe or from merely one by how it looks. When the same microbe attach to one another they become colony-forming units which will have the same appearance as one another, yet as different species form their own colony, the appearance should be distinguishable. This will then allow you to determine if there is a mixture, or just one. clinical application You can conclude that the swab samples taken has the least bacterial growth on them because you had taken the matter with a sterilized swab in which you then put on the nutrient agar to grow. On the other hand, when you use the rodac environment plate, there is more contaminant that allows more colonies to form and is therefore not as clean as the swab samples which would have you use the swab instead of the rodac plates. Exercise 5: Preparation of Smears and simple staining Purpose is to prepare and fix a smear. Then be able to list advantages of staining microorganisms and explain the basic staining mechanisms and be able to perform a direct stain. Expected Results 1. Coccus 2. Rod 3. Bacillus is a species that is a rod Results 1. Bacteria : Staphylococcus Epidermidis

100 x Coccus & Spiral Shaped Clustered

Conclusion 1. Staphylococcus Epidermidis would be closest to a rod shape 2. Staphylococcus Epidermidis was the larger bacteria.

Bacillus Megaterium

100x Coccus shaped Free Floating (?)

Questions 1. A simple stain is important because it allows you to see one bacteria and therefore helps you determine the size and shape of that bacterial organism. 2. Heat fixing a smear allows you to kill any contaminants that may be on the smear. 3. Alcohol chemically fixs the bacteria by making it less hydrophilic and therefore when you wash the smear in anything, the bacteria will not be disturbed. 4. If too much heat was applied you would denature the cells, including the ones you want to sample Critical thinking 1. The pH of the stain could affect the staining of the bacteria by changing the charge of the bacteria which would then affect the shape that the sample may become. this would then ruin your results. 2. other dyes cannot be used because methylene blue has a property in it that has charged ions which allows the dye to mix with the sample and show the color of whatever ion the sample may be (either - or +) . other dyes may not have this characteristic. Clinical application 1. Even though bacteria can be seen without staining, some bacteria cannot be seen with the naked eye therefore staining and fixing them does not only allow for a physical substance to always refer to, but can also tell a lot about a certain type of bacteria that may cause a disease. 2. the saline is not contaminated Exercise 6: Negative staining purpose is to explain the application and mechanisms of negative stain techniques and to also prepare a negative stain. expected results 1. negative stained rod:

2. the bacillus subtilis should be rod shaped. results

Bacillus Subtilis

Staphylococcus Epidermidis

Tooth&Gum

10x Coccos and Rod

10x Coccus

10x Coccous&Rod

Conclusion 1. Bacillus subtilis and the tooth and gum bacteria were rod shaped. With the methylene blue stain, the rod shape was more exact and easy to distinguish, however, since with a negative stain the background is typically black, the rod shape was harder to make out in my slides. 2. I observed 2 different type of morphologies that really stuck out for the tooth and gum scraping. Questions 1.the size is more accurate in negative staining because you do not stain the bacteria, but merely the background, which allows you to see the shape more than a direct stain. 2. the toothpick was placed in the disinfectant because of the various bacteria found in the toothpick after scraping the surface of your teeth. it was no longer sterile and had various DNA from yourself and the classmates around you which you would not want to handle. Critical thinking 1. possibly controlling the light that enters the microscope can give an appearance similar to a negative stain. 2. the pH would have to be acidic or less… making the pH be...