• Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

The objective of this lab was to determine if different cultures would successfully grow on diverse agar medias and to distinguish the appearance of growth on the mediums.

Extracts from this document...

Introduction

´╗┐The objective of this lab was to determine if different cultures would successfully grow on diverse agar medias and to distinguish the appearance of growth on the mediums. The experiment involved three different types of growth medias - selective, differential and enriched. The experiment also involved four broth cultures - Escherichia Coli, Enterobacter Aerogenes, Staphylococcus Epidermidis and Streptococcus Faecalis. Selective media was a growth medium that enhanced and inhibited the growth of certain organisms due to an added media component (Madigan et al., 2012). The selective medium used in this experiment was KF Streptococcal Agar. Differential media allowed the identification of microorganisms based on observable properties (Madigan et al., 2012). In this experiment, the differential media used was Eosin Methylene Blue (EMB) Agar. The methylene blue in EMB inhibited the growth of gram-positive bacteria and only allowed gram-negative organisms to be grown. EMB had a pH of 7.2 and used lactose and sucrose for energy. (Madigan et al., 2012) Enriched media allowed metabolically fastidious organisms to be grown because of the added specific growth factors (Madigan et al., 2012). ...read more.

Middle

The amount of growth ranges from abundant (++++) to none (-). MEDIUM MICROORGANISM GROWTH DESCRIPTION TSA Escherichia Coli Enterobacter Aerogenes Staphylococcus Epidermidis Streptococcus Faecalis ++++ ++++ ++++ ++++ White to beige White to beige White to beige White to beige EMB Escherichia Coli Enterobacter Aerogenes Staphylococcus Epidermidis Streptococcus Faecalis ++++ ++++ - - Green metallic sheen Pink mucoid; dark centre No growth No growth KF Escherichia Coli Enterobacter Aerogenes Staphylococcus Epidermidis Streptococcus Faecalis - - - +++ No growth No growth No growth Pink to red colonies Discussion: After completing the experiment, we can note that each medium used produced different results. The results showcase the differences between enriched, differential and selective media. The enriched media, TSA, had growth for all four different cultures. In this experiment, TSA acted as a growth medium because the most common and even fastidious forms will grow on this medium. TSA is also known as Soybean-Casein Digest agar (Dickson, 2002). It can be considered a defined medium because it can be easily replicated. ...read more.

Conclusion

The KF media, being a selective media, promotes growth of only one type of organism and discourages the growth of any others (Madigan et al, 2012). It makes sense that the medium was selective in producing the growth for its own relative organism. In conclusion, enriched, differential and selective mediums produced different growth results for each culture. The enriched media, Tryptic Soy Agar, produced identical looking growth observations for all four organisms. The differential media, EMB, showcased the difference in gram positive and gram-negative medias by turning them different colours; pink for E. Aerogenes and green for E.Coli respectively. Lastly, the selective medium, KF, promoted the growth of one culture, Streptococcus Faecalis, and discouraged the other cultures. Resources: Department of Biology, 2012, Biology 240 Fundamentals of Microbiology Laboratory Manual. University of Waterloo. pp. 45-47. Dickson, J. (2002) ?MadSci? Faculty, Microbiology, Iowa State University. Oct 2012. < http://www.madsci.org/posts/archives/2000- 02/951527342.Mi.r.html> HiMedia. ?Technical Data: KF Streptococcal Agar Base? Oct 2012. < Himedialabs.com/TD/M248.pdf> Madigan, Martinko, Stahl, Clark. 2012. Brock Biology of Microorganisms, 13th Ed. Benjamin Cummings. San Francisco. Pp. 884-888 Liu, S. (2005) ?Science Buddies: All About Agar?. Oct 2012. <http://www.sciencebuddies.org/science-fair projects/project_ideas/MicroBio_Agar.shtml> Wellesley College BISC 209 Microbiology (2010) ?OpenWetWare? Oct 2012. < http://openwetware.org/wiki/BISC209:_Selective,and/or_Differential,_and/or_Enriched_media> ...read more.

The above preview is unformatted text

This student written piece of work is one of many that can be found in our University Degree Microbiology section.

Found what you're looking for?

  • Start learning 29% faster today
  • 150,000+ documents available
  • Just £6.99 a month

Not the one? Search for your essay title...
  • Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

See related essaysSee related essays

Related University Degree Microbiology essays

  1. Use of selective and differential media to identify bacteria

    Using the streak plate technique, a loopful of the mixture is placed onto the nutrient agar plate then the MacConkey agar 1 plate and MacConkey agar 3 plate. The plates were stored at 40C for a day and then incubated at 370C less than 24hours.

  2. Free essay

    Identifying microorganisms using differential staining techniques

    to distinguish between acid-fast bacteria and non-acid-fast bacteria contained in the cell (Kelleher, 2004). Seeing that the acid-fast bacteria contain strong cell walls they will remain the same pink colour, while the non-acid-fast bacteria become clear because the acid from the decolorizer is able to remove the carbolfuchsin from the weak cell walls (Kelleher, 2004).

  1. Bacterial Metabolism and Enzymatic Growth

    To better see the clearing, Gram's iodine solution was added to the agar plate and any starch present was stained. Lipolysis activity, which is the breakdown of fat, is evident if the area around which the bacterium was spotted on the tween 80 agar is cloudy.

  2. Introduction to Spectrophotometric Analysis - By using spectrophotometric analysis or spectrophotometry, one can determine ...

    absorbance measured was 0.488 at a wavelength 411nm, 0.058 at a wavelength 540nm, and 0.055 at a wavelength 577nm. However, after sodium dithionite was added, the oxyhaemoglobin became deoxyhaemoglobin where the oxygen is released from the haemoglobin and this result in an absorbance measurement of 0.421 at a wavelength of 428nm.

  1. COSHH Risk Assessment for a Laboratory

    This is very important especially in the use of carcinogens, mutagens and asthmagens. These are all harmful to health. Use of PPE can be very useful in controlling exposure. Step 4 is simply to maintain the use of control measures, this is to say to be consistent with usage of

  2. Distinguishing Species of Bacteria

    (Madigan and Thomas, 2009)In table 9, Bacillus subtilis showed positive result on the starch hydrolysis whereas Escherichia coli did not. Starch hydrolysis requires the presence of exoenzyme amylase to hydrolyze starch into smaller polysaccharides. (Madigan and Thomas, 2009) Positive result of starch hyrdrolysis showed the ability of the mircoorgism to produce amylase.

  1. Folic acid. In 1993 the Food and Drug Administration (FDA), in the USA suggested ...

    Although folic acid deficiency is not the sole factor for NTD occurrence it still plays a major role but the environment and genetic factors may have a little affect and this should be recognised. Prevention of oral and facial birth defects such as cleft palate occurring is also done by folic acid.

  2. This review looks at how silicification of bacteria allows preservation of the bacteria through ...

    (1986) Iron-silica crystallite nucleation by bacteria in a geothermal sediment. Nature 320, 609-611. 18. Oehler J. H. and Schopf J. W. (1971) Artificial microfossils: Experimental studies of permineralization of blue-green algae in silica. Science 174, 1229-1231. 19. Toporski J.

  • Over 160,000 pieces
    of student written work
  • Annotated by
    experienced teachers
  • Ideas and feedback to
    improve your own work