Abstract This paper describes a blood agar mouth swab lab experiment whose purpose is to show that Streptococcus sp. is present in all mouths. The experiment uses sheep blood agar and swabs taken from volunteers which are left in a petri dish overnight. The paper also includes tables and diagrams.
Outline:
Objective
Materials and Methods
Results
Interpretation
From the Paper "The agar used was Sheep Blood Agar. According to Colome, et. al., 1986, Blood Agar includes 1 liter of sterile, molten blood agar base medium which has been cooled to 50 to 55 degrees C., and 5% (v/v) of sterile, defibrinated sheep blood which was added aseptically. Further, "[a]ny of several complex infusion agar media may be suitable for use as a blood agar base, including heart infusion agar, Columbia blood agar base, neopeptone infusion agar, tryptic soy agar, etc." all of which should be rich in nutrients and have a final pH of 7.2 to 7.4. This particular medium lacks carbohydrates like dextrose which are fermentable. The sheep blood is used in this particular agar because hemolysis will be able to be proven by a change in the blood or color of the agar. In particular, Streptococcus will lyse the blood in the agar. Alpha-hemolytic Streptococcus will turn it a green and beta-hemolytic Streptococcus completely lyses the sheep blood turning it from red to clear. "
Abstract This report discusses the results of the effects of the nutrient, agar on bacteria found on bathroom surfaces. The report describes the materials used and the methods in which they are used. The paper then examines and interprets the results of the experiment. This paper includes tables and graphs that illustrate the findings of the test.
Table of Contents:
Objective
Materials and Methods
Results
Interpretation
References
From the Paper "The agar used was Nutrient Agar. According to (Colome, et. al., 1986), Nutrient Agar includes 3.0 g Beef extract, 5.0 g Tryptone, 15.0 g Agar and 1000.0 ml Distilled water. The final pH is 7.0 at 25 degrees C. This is a complex infusion agar that "supports the growth of nonfastidious heterotrophic microorganisms" (D11). It can be a selective media depending on what nutrients are added. According to Bauman (2009), "Selective media typically contain substances that either favor the growth of particular microorganisms or inhibit the growth of unwanted ones" (p. 180). Here, however, the nutrient agar is being used to grow whatever bacteria it might be inoculated with."
Abstract The writer points out that the purpose of this laboratory was to acquire fundamental knowledge and experience in microbiological procedures, specifically in growing bacterial colonies on a nutrient medium under controlled conditions. In this case, Escherichia coli (E. coli) bacteria were grown on nutrient agar, contamination was minimized by keeping the surroundings sterile, and all agar plates were incubated. The writer notes that the first part involved making five serial dilutions from a bacterial suspension in order to pinpoint colony numbers. The second experiment compared two methods of spreading bacteria across agar plates using streaks. The goal was to isolate single colonies. Lastly, the third portion of the laboratory involved replicating plates from a master plate in order to isolate strains of mutant bacteria onto different nutrient mediums and determine bacterial auxotrophy to these nutrients.
Outline:
Introduction
Materials and Methods
Results
Discussion
References
From the Paper "In the streaking experiment, method B proved to be much more effective for isolating single colonies. The different streaking methods may have contributed to the morphological differences between the E. coli on the two plates. There were evident differences in the size and colour. Since method B was dominated by spaced out single colonies, the darker colour and larger size can be attributed to more nutrients being available to each colony, and more room (surface area) for growth. For the same reason, the more crowded groups of bacteria on the method A plate were a lighter colour and generally smaller. Aside from these two differences, the E. coli shared great resemblance, and based on morphology alone, should not be classified as different species. Nonetheless, the only way to determine whether or not two sets of visibly different bacteria are genetically different is to actually observe their DNA."
Abstract This paper presents a formal biology laboratory report. It presents a procedure that was devised to remove all bacteria from a chicken wing. It begins by discussing the bacteria that can be present on chicken wings and the possible solutions to the problem. The paper then reports on a test for the efficacy of certain antibiotics on the bacteria of the untreated wing.
Table of Contents:
Abstract
Introduction
Materials and Methods
Study Organisms
Treatment Of Choice For Elimination Of Bacteria From A Chicken Wing
Serial Dilutions Of Washes From Both Wings
Gathering Of Bacterial Cultures From Both Wings
Effects Of Various Antibiotics On Three Types Of Bacteria
Results
Control Agar Petri Plate
Treatment Agar Petri Plate
Antibiotic Disk Results
Chicken Wing Bacteria
Discussion
Appendix
From the Paper "It is important to remove all bacteria, such as salmonella, from raw foods to avoid any foodborne diseases. Four serial dilutions were created in microfuge test tubes for a control chicken wing and a treatment chicken wing. The treatment chicken wing was treated using vinegar, salt, and heat. Cultures from each microfuge test tube were streaked on two different agar plates and left to reproduce, incubated at 30o Celsius for 22 hours. The proposed treatment of the chicken wing proved to be 100% effective producing no visible colonies on the agar plate. Four antibiotics - penicillin, streptomycin, tetracycline, and chloramphenicol - were used to treat E. coli, M. luteus, and chicken wing bacteria. The bacteria cultures were smeared on three different Petri dishes, and divided into four quadrants where antibiotic disks were placed. After 22 hours of incubation at 30o Celsius, diameters of the rings of clear agar around each antibiotic disk were recorded. Chloramphenicol produced the largest diameter on all three Petri dishes, while penicillin proved to work best on gram-positive bacteria. The bacteria on the chicken wing were gram-negative and most resistant to tetracycline."
Abstract This paper deals with how spots occur (inflamed lesions), and their subsequent bacterial growth. It gives details into how the effect of various concentrations of anti-bacterial facewashes affect the spread of bacteria. A thorough experimental aceptic technique is made reference to in this paper.
From the Paper "A spot starts when a pore in the skin becomes blocked ? usually with oil (sebum) and dead skin cells, which the skin produces. As the pore becomes blocked, it becomes infected with bacteria, which are normally present on the surface of the skin. These bacteria breakdown the oil and dead cells to form chemicals which cause swelling, redness and the formation of an "inflamed lesion" or a SPOT."
Abstract This paper defines the term cytotoxicity and then presents an overview and critique of eye cytotoxicity tests: agar diffusion method; fluorscein leakage test; neutral-red uptake test; MTT-based cytotoxicity assay.
From the Paper "This research paper provided an overview and critique of the agar diffusion method, the fluorescein leakage test, the neutral-red uptake test and the MTT-based cytotoxicity assay. Cytotoxicity refers to a toxic effect at the cellular level such as altered cellular membrane permeability death or enzymatic inhibition. A toxic material is one that releases a chemical that kills cells directly or indirectly. Cell culture methods are used to evaluate cytoxicity bio compatibility and functioning of materials in the in vivo environment. Testing procedures are used for..."
Abstract This paper describes an experiment that was designed to determine the fate of Dictyostelium that had been transected while in the slug stage and placed inside an agar plate for a one week period with no nutrients. The paper aims to gain knowledge, through the experiment, on the life cycle of Dictyostelium, particularly in the slug stage and how they will communicate with their individual cells and themselves as a whole after being transected.
Table of Contents:
Abstract
Introduction
Materials & Methods
Results
Discussion
From the Paper "Cell-autonomous mechanisms play an important role in initial cell-type choice and the subsequent regulation of cell-type differentiation (Gomer and Firtel, 1987). Although further research is still required on differentiation and aggregation, it is known that cells lacking the protein Spn arrest as tight mounds before breaking up into smaller aggregates (Brown J. and Firtel R., 1999). Dephosphorylation of a specific Spn substrate(s) is a limiting step in the differentiation of prestalk cells. Spn may be required for the initial formation of prestalk cells andor ALCs, which induce neighbouring cells to adopt a prespore fate. The production of a prespore cell induction factor by prestalk cells has previously been proposed by studies of the heterotrimeric G-protein subunit Ga4 (Hadwiger J. A. and Firtel R. A., 1992)."
Abstract This paper explains that virtually all bacteria strains have viruses specific to them. The paper then describes an experiment that takes coliphages from sewage and, after enrichment and filtration processes, exposes the E.Coli R10 strain to the phages to obtain the phage specific to the strain. The paper further explains that the bacteria strains are grown on agar plates in the presence of coliphages, and strains W3104-A on plates K12 and W3104 and R12-B on plate K12 developed resistance. The paper then reports that the W3104-A strain is further tested and retains its resistance.
Table of Contents:
Abstract
Introduction
Materials and Method
Isolation and Enrichment of Coliphage from Raw Sewage
Filtration of Coliphage Mixtures
Dilution and Plaque Preparation of R10A and R10B E. Coli Strains
Mutation and Isolation of Phage-Resistant E. Coli Strains
Sensitivity of Phage-Resistant Mutants to Bacteriophages
Results
Discussion
Table: Colonies of Bacterial Strains Response to Coliphages
From the Paper "Bacteria have the ability to develop resistance to viruses [6], so as it can be expected some strains (namely W3104-A and R12-B) developed phage-resistant colonies. It is known that certain genetic elements called "episomes" are instrumental in creating phage-resistance in E. Coli strains such as K12 [8]. As indicated in table 1, there were numerous contaminations; this was certainly due to many of the unfiltered cultures that were used. This was done because of time constraints and shortage or missing supplies in the lab."
