Bacteriology 102:
Guidelines for Preparing Formal Laboratory Reports

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Report Guidelines
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This web page replaces Appendix 11A in the Lab Manual. Note that we no longer do posters in this course. How we grade these reports (i.e., those associated with these specific guidelines) is the subject of this page.

Note that this is one of the truly archived pages for the old Bacteriology 102 course website, and these guidelines are not applicable presently. After 2007, updated guidelines have been included in the lab manuals.

One report is required, and it can be on one of the following experiments: 10.2, 11.1, 11.2, 11.3. (Note that we are no longer doing Exp. 9.3.) A report is strictly an individual project. We have some samples of reports from previous semesters. These are not necessarily meant to be perfect examples to follow, as we continue to increase our expectations.

The more you understand how the characteristics of the various kinds of bacteria can be exploited in order to recover them in pure culture from their natural source, the better will be the information value of your report – in the Introduction and (especially) the Discussion. Filling out the table on the handout (reproduced here) as you go through the experiments will help considerably.

We are interested in what you observed – not what should have been observed in any ideal situation. We do not expect each sample to yield the same number or variety of organisms! There is no "key" for the samples we use, nor should or can there be. For example, do not expect each different colony of photosynthetic bacteria to represent a separate genus. (Even though one might see several different colors or sizes of colonies on the plate, they could be of several species of Rhodobacter.) Likewise, in the Bacillus experiment, each differently-appearing colony on the plates from the heat-shocked inoculum probably represents a different species of Bacillus. We never expect to find the same species or strain we work with in our experiments. If we were still doing Experiment 9.3, we would certainly never expect to find phage strains "JL-1" or "KX-32"!

We insist that terms be used appropriately. Problems often arise regarding singular vs. plural forms (medium vs. media, inoculum vs. inocula, genus vs. genera, etc.) and the correct way to indicate scientific names. A true microbiologist, comfortable with his/her field and regularly doing lab work, never says "media is." See page 149 which summarizes a number of fundamentals; this material is also reproduced here. The concept of scientific names should be familiar material which would have been covered in previous biology courses of any level.

For the reports, you must properly acknowledge the sources of any facts you cite from others. "Quoting, Paraphrasing and Acknowledging Sources" is the title of a handout from the Writing Lab at the Helen C. White Library which we have made available in connection with our discussion of writing formal reports. The expanded handout is on the web here where the most relevant section for us is "Quoting and Paraphrasing." Another relevant section deals with documentation – i.e., referencing which is something we can discuss in lab as needed. The American Society for Microbiology has downloadable referencing guidelines for its journal authors; an example can be found here.

Feel free to use whatever referencing system you wish – just as long as it is consistently applied! However, you must pay heed to the following:

  • Every "borrowed" quotation, image, table or other item – as well as each hard fact that a reader may wish to pursue – must be referenced where it is used in the report.

  • If you utilize anything from the web, make sure that the URL of the web page on which the specific item is found is correctly referenced. Do not give the specific URL of an image but rather the web page on which it is found. Citing the URL of the entire site or its home page may not get the reader to the specific item being referred to without a lot of extra searching and hassle, as many websites can be extremely difficult to navigate. When listing web pages among your references, include the author and date (if shown) and also the title of the page. Make sure that whatever image(s) you use is (are) correctly labeled as to what is being represented! Do not state or imply that you got the result illustrated on any of these images from the web.

  • It may be most handy to have all references listed together and numbered, such that any reference can be referred to by its number (rather than the more cumbersome author, page no., etc.) wherever it is cited in the text of the report.

Be careful how items are discussed, especially in the Introduction and Discussion. Avoid "mixing apples and oranges" – an example being the frequently-seen classification of nitrogen-fixing organisms into three groups: non-symbiotic (i.e., free-living), symbiotic, and cyanobacteria. Some cyanobacteria fix nitrogen in symbiotic relationships (e.g., lichens) and the other nitrogen-fixing cyanobacteria are free-living. So, the primary groupings of nitrogen-fixing bacteria should just be non-symbiotic and symbiotic. Another thing that is seen too frequently in reports is the statement that nitrogen-fixers "pull" their nitrogen out of the atmosphere. It is mentioned in this fashion in the lab manual, but it is technically not correct and will not be stated in this manner in future editions of the manual.

Your report should follow the format of a typical scientific journal article of which Steenbock Library has thousands. Journals such as Applied and Environmental Microbiology and the Journal of Clinical Microbiology can be consulted to get an overall idea of the format of a scientific paper – how it is arranged in logical sections. (We will not require you to prepare an "abstract.") See how these papers summarize much of their results in tables, and how these tables are referred to from the text of the paper. Another valuable thing one can pick up from these journal papers is how references to other publications are made. Please do not feel you must necessarily use material from journal papers in your report. However, you may find relevant items that can make your report more interesting and informative.

This is to be a formal, typewritten report with references to quoted material appropriately made and organized with labeled sections as indicated below. This is also meant to be a summary of your work. WARNING: It is very easy for seasoned instructors to note replications of phraseology and results between the reports submitted. Also, any indication of procedures which could not possibly have been accomplished will taint the rest of the report and result in a grade of zero for the entire report.

Please type on one side of the page only, and do not use plastic covers. You must make a copy of your report! The instructors do not expect to lose any submitted papers, but making a backup copy is always desirable. As it may take quite awhile for the instructors to read these papers, one can utilize the backup copy as a study aid. If you have problems, be sure to consult the instructor.

An example of a lab report submitted in a previous semester (when our guidelines were not so detailed) can be found here.



State the purpose of the experiment. Then, summarize the major characteristics of the bacterial group under consideration as if you were writing to one having some biological experience. Include what special features of the bacteria we are exploiting in order to isolate them selectively. Incorporation of interesting material on these organisms from outside readings is expected in an "A" paper. This section, being an introduction, should not be a past-tense summary of what you did. It should rather serve as a "set-up" for the following sections.


This section should serve as a summary of the procedure and materials used. For our purposes, you need only refer to the pages in this lab manual that include the materials and methods used in the experiment. There is no need to copy the list of materials or the procedure you followed as long as no changes were made from the protocol in the manual. Any changes (deletions and/or additions directed by the instructor or made on your own initiative) must be specifically noted! For example, if you gram-stained the Bacillus colonies or performed any other test not indicated in the manual, you must make that clear in this section! As another example, one would need to say "the soil suspension was heat-shocked at 85°C for 18 minutes" if that was actually done instead of the prescribed procedure.

Having made note of incubation times and temperatures as you performed the experiment, it is a good idea to include them here if they do not correspond to the manual. Also, for each group of bacteria studied, indicate the specific source material used. (This includes location and date collected.) This was indicated at the beginning of each procedure for the water or soil samples provided by the instructor.


Include in this section all data (observations, results, etc.) collected during the experiment. Summarize your observations of the individual isolates in table form as much as you can. For some general table guidelines, click here; one example is seen in the lab manual on page 52. Each table should include column headings indicating isolate designation (number or letter), colonial characteristics, microscopic observations and each additional test. For example, in the Bacillus experiment, you would need to include the catalase, amylase and any other tests and observations done on the isolates. Be sure that each table is clearly referred to from the text of this section.

Non-tabulated observations (i.e., those you would put only in the text of this section) would include observations of broth enrichments (done in the photosynthetic and nitrogen-fixer experiments), comparisons of plates (colony numbers and variety such as what is asked for in the Bacillus experiment), and other such observations which would not fit in tables for individual isolates.


Discuss the major points of the isolation procedure and whether or not you were successful in isolating the desired organisms. Answers to the following are expected in an "A" paper and should be easily derived from the filled-out table here (or on the equivalent handout).

  • Consider why the particular source material that you used was expected to contain the desired organisms – either making it their habitat or significantly contaminating that site. (The instructor can tell you about finding purple non-sulfur photosynthetic bacteria in rain and snow – certainly not "habitats" for any organism.)

  • Discuss any special treatment of the inoculum. As an example: Why was the soil suspension in the Bacillus experiment heat-shocked? (There are at least two reasons.) Also, what was significant about filtering the source material in the bacteriophage isolation experiment?

  • What media were used to obtain the isolates? How were these media selective (if selective) and why? How did the enrichment and isolation media aid in obtaining the desired organism? For example, consider the reasons why succinate was important in the enrichment and isolation of the purple non-sulfur photosynthetic bacteria; also think about why these organisms are called "non-sulfur."

  • What were the significant things about the conditions of incubation?

  • Was the procedure successful? That is, were the results in line with the general expectations? What criteria were used to determine success? If you were not successful, what problems did you encounter? What better source materials, media and procedures could have been employed?

Stated in your resources are some questions whose answers can be woven into the Discussion as you feel appropriate. These questions can be found (1) in the introductions and procedures of the experiments in the manual, (2) in Appendix X of the manual, and (3) on our enrichment & isolation page.

GRADING THE REPORTS:  This topic is covered here.


An old Laboratory Report
Flow Charts and Tables
Enrichment and Isolation
Selected Microbial Groups
Bacteriology 102 Website

Pages on the Bacteriology 102 Website have copyright by John Lindquist and found their permanent sanctuary on in 2001. Subsequently this site was "retired" and archived with the coming of the new largely-virtual 102 lab in 2007. However, updates of content regarding subject matter continue to be inserted as necessary. Absolutely none of these pages have been authorized for reproduction on .edu websites. Beware of web piracy!

Content of this page was last modified on 5/6/10 at 11:45 AM, CDT.
John Lindquist, Department of Bacteriology,
University of Wisconsin – Madison