Bronx High School of Science



The Bronx High School of ScienceScience DepartmentV. Reidy, PrincipalJ. Donahue, A.P. ScienceL. Pride, Microbiology InstructorThe Biochemical Identification of a Microbial UnknownLAB REPORTSuggestions for Structuring the Paper:Unknown reports in microbiology are written in scientific format. The purpose of scientific writing is not to entertain, but to inform. Scientific writing is typically written in the passive voice. The pronouns "I", "We" and "They" are not typically used. For example, instead of writing "I used a TSA agar plate to isolate my unknown," it is customary to write, "A trypticase soy agar (TSA) plate was used to isolate the unknown." It is also customary to write in the past tense for most of the report. This includes the introduction, the summary, the description of the materials and methods and the results. he name of the bacterium should be written and spelled correctly. The name should be italicize, for example, Staphylococcus aureus. The first letter of the genus name is capitalized, but the species is not. After the full genus name is given in the paper, it can be written as S. aureus, but still italicized throughout the remainder of the paper. PARTS TO THE UNKNOWN LAB REPORT(Note: Other than the title page, the pages of the report must be numbered)I. TITLE PAGETitle page should include the following information:UNKNOWN LAB REPORTUNKNOWN # (Enter your assigned number)NAMEDUE DATE: JANUARY 3, 2010Ms. Leah D. PrideSBM1 MICROBIOLOGYFALL2010II. INTRODUCTIONThis section introduces the background information for this particular project. Include overarching information on metabolic pathways and the importance of using biochemical testing as an assay for microbial identification. The last paragraph of the introduction should introduce the reader to your study and explain why the study was done. Be sure to include a working hypothesis. Example for what to include in the last paragraph: "There are many reasons for knowing the identity of microorganisms. The reasons range from the knowing the causative agent of a disease in a patient, so as to know how it can be treated, to knowing the correct microorganism to be used for making certain foods or antibiotics. This study was done by applying all of the methods that have been learned so far in the microbiology laboratory class for the identification of an unknown bacterium." The introduction should be at least 1.5 pages long (double spaced, 1 inch margins all around, 12 font Times New Roman- consistent font throughout the body of the paper).MATERIALS AND METHODSThis is where the details of the study are listed. Where did the specimen come from, and what methods were used to identify it? Be specific, but do not re-write the lab manual. See the example below:Example: "An unknown labeled as letter G was given out by the lab instructor. The methods that have been learned thus far for identifying bacteria have been applied to this unknown. Procedures were followed as stated in the course laboratory manual by Cappucino (1). The first procedure that needed to be done was to treak the unknown out on a Trypticase Soy Agar plate, using the T streak method described in the lab manual. This needed to be done in order to test the purity of the unknown. After the plates were incubated and grown, the morphology was observed and recorded and a Gram stain was performed. After determining the Gram reaction, specific biochemical tests were performed. Table 1 lists the test, purpose, reagents and results. All of the following tests were performed on this unknown:1. Oxidase test2. BCP Lactose3. Indole4. H2S5. Citrate6. Motility7. Methyl Red8. Urea"The materials and methods section should be in detailed (again, do not repeat the lab manual) paragraphs. Please do not list any of the steps conducted for the biochemical tests, create concise sentences summarizing the overall procedure you employed to conduct the specific biochemical test. RESULTSThis is where the results are summarized and described (not explained). Table 1 mentioned above (i.e. Table 1 lists the test, purpose, reagents and results) should be the first table included in your results section. This is also where the flow chart showing how you arrived at the answer is stated. Please consider the example included as a way to organize the flowchart. A short paragraph explaining how the results are presented can be included. In the results section, you should include the microscopy pictures you generated from the staining procedures (e.g. Gram stain, Methylene blue, Nigrosin staining). If you would like to take pictures of your plates or test tube results using a camera, please let me know in advance. Following approval, please organize them appropriately in the results section with titles and captions. Separate table(s) including the actual scoring of your biochemical test must also be included in the results section.Example: Figure 1: Colony characteristics of Unknown GUnknown G had the following morphology on a TSA plate: medium sized opaquecream colored colonies. DISCUSSION This section analyzes and interprets the meaning of the results. The following questions should be answered here: How did the biochemical test results lead to the identification of your unknown? What problems were encountered? This is also where the background information on the organism(environment/pathogenicity) that was identified is mentioned.Example of a discussion: After several differential tests, it was concluded that unknown G was Escherichia coli. After performing the Gram stain to determine that the unknown was a Gram negative rod, the organism was grown on a TSA slant for use in inoculating the rest of the biochemical tests. All of the biochemical tests worked well except for the indole test. It gave a false negative result at first. This was determined since it was inconsistent with the rest of the result. The test be repeated and it was repeated. The repeated test gave a positive result, consistent with the other data. Therefore it was concluded that the unknown was Escherichia coli. E. coli is in the Enterobacteriaceae family. It is typically found in the human intestines, but can also infect other organisms as a pathogen.Expand the Discussion section, as necessary. It is the second most important section of the paper, the most important being the methodology. .REFERENCES:The minimum number of references is three, but you can include as many as necessary. Correct reference format must be used. APA formatting of the reference section should be followed. Please follow APA formatting for in-text citations, as well. References should be numbered and the number added to the report when necessary. Spelling of the authors’ names for the references must be correct.ADDITIONAL POINTS:1. Attach copies of both the working results worksheet and the final worksheet. 2. Attach the unknown identification table that was used for identifying the unknown with themarks used to help narrow down results.3. Number the pages.4. Use a spell checker and check for grammar mistakes.5. HAVE FUN WITH THE IDENTIFICATION OF YOUR UNKNOWN! You are an investigator in this project, so look at this project as a mystery you are trying to deduce. Overarching Problem: How do we biochemically confirm the identity of an unknown microbe? BIOCHEMICAL TESTING SCHEDULE 2010DATEBIOCHEMICAL TEST12/15Carbohydrate Fermentation Test Triple Sugar-Iron Agar Test12/17Extracellular Enzymatic Activity12/20IMViCLitmus Milk Reactions12/22IMViCNitrate Reaction Note: You must schedule time to do the simple, negative and Gram stain procedures. Remember, you can use SGI, off days, or after school to conduct lab work. If I am available, you have access to the lab room. Talk to me after considering your schedule and mine (posted outside 329D). Pre-Lab Organization:Before arriving for the aforementioned laboratory session to conduct a biochemical test, please come prepared with the following:I. Statement of purpose for the biochemical testII. What are the essential reagents needed for the biochemical test?III.Short description of the methods (e.g. words, flowchart, etc.) to orient you and so as to not waste time. I will check to see that you have this, and it is required for you to complete the laboratory exercise. IV.A copy of your unknown worksheet for scoring previously inoculated samples. ................
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