selective and differential media lab report conclusion

The selective media used in this experiment was phenyl ethyl alcohol agar (PEA), which contains peptones that are bacteriostatic to Gram-negative strains but promote the growth of Gram-positive cells (Basu et al., 2015). The Journal of Horticultural Science and Biotechnology, 19(2), 122-128. Journal of Pure and Applied Microbiology, 10(4), 1-7. State the usefulness of Columbia CNA agar and MacConkey agar. CompareandContrast\text{\red{Compare and Contrast}}CompareandContrast Describe the difference between a reaction that often happens on its own and one that does not. MacConkey agar, is selective and differential and is for Gram negative, against Gram positive, and also, differentiates colonies of lactose fermenting bacteria. Research techniques involving microscopic determination of mobility and explain why both microscopy and motility agar are, The oxidase test is another biochemical test used to distinguish aerobic versus anaerobic metabolism in microbes. contaminated water or stale food. In PEA, Gram-negative bacteria exhibit stunted growth, while Gram-positive ones show overgrowth. Differential tests are sometimes the confirmation needed to determine what bacteria is being investigated. Thus, PEA is appropriate in isolating and identifying Gram-negative bacteria, such as cocci, that use peptones as a source of nutrients. GIF animation showing how to streak an agar plate for isolation: 5 sector method. Mannitol Salt Agar and its expected there would be a change in the medium color due to the A. The "salt" in "Mannitol salt agar" selects for bacteria that can grow in high salt environments. Today we will combine both a mechanical isolation technique (the streak plate) with selective and selective-differential media to obtain pure cultures from a mixture of bacteria. { "00:_Front_Matter" : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()", Final_Project : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()", Introduction : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()", "Lab_01:_Introduction_to_the_Microscope_and_Comparison_of_Sizes_and_Shapes_of_Microorganisms" : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()", "Lab_02:_Aseptic_Technique_and_Transfer_of_Microorganisms" : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()", "Lab_03:_Obtaining_Pure_Cultures_from_a_Mixed_Population" : "property get [Map 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MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()" }, Lab 3: Obtaining Pure Cultures from a Mixed Population, https://bio.libretexts.org/@app/auth/3/login?returnto=https%3A%2F%2Fbio.libretexts.org%2FLearning_Objects%2FLaboratory_Experiments%2FMicrobiology_Labs%2FMicrobiology_Labs_II%2FLab_03%253A_Obtaining_Pure_Cultures_from_a_Mixed_Population, \( \newcommand{\vecs}[1]{\overset { \scriptstyle \rightharpoonup} {\mathbf{#1}}}\) \( \newcommand{\vecd}[1]{\overset{-\!-\!\rightharpoonup}{\vphantom{a}\smash{#1}}} \)\(\newcommand{\id}{\mathrm{id}}\) \( \newcommand{\Span}{\mathrm{span}}\) \( \newcommand{\kernel}{\mathrm{null}\,}\) \( \newcommand{\range}{\mathrm{range}\,}\) \( \newcommand{\RealPart}{\mathrm{Re}}\) \( \newcommand{\ImaginaryPart}{\mathrm{Im}}\) \( \newcommand{\Argument}{\mathrm{Arg}}\) \( \newcommand{\norm}[1]{\| #1 \|}\) \( \newcommand{\inner}[2]{\langle #1, #2 \rangle}\) \( \newcommand{\Span}{\mathrm{span}}\) \(\newcommand{\id}{\mathrm{id}}\) \( 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Record your observations and conclusions. Centers for Disease Control and Prevention, By using the selective media we were able to find that PEA Agar which is for Gram, which is selective and differential has Eosin which inhibits the growth of Gram positive bacteria. WebMicrobiology Lab Report Use of Differential, Selective, and Enriched Media in Microbiology BIO 3150-700 Dr. Marilu Santos Introduction: The purpose of this experiment is to display the numerous special media used to isolate bacterial types, the differences between closely related groups of bacteria, the practice of sanitation and aseptic fermentation. shows how the two microbes E. coli and Aureus respond on being inoculated into the Eosin Wallace, J. S., & Jones, K. (1996). bacteria and encourages the growth of gram positive bacteria. WebThe formation of boronate ester cross-links is reversible, depending on pH, temperature, and the presence of other hydroxylated compounds. Differential media takes advantage of biochemical properties of target organisms, often leading to a visible change when growth of target organisms are present. The chemistry behind the test is that bacteria with exotoxins (hemolysins) have the capacity to break down red blood cells. Development of a selective and and enhances the growth of Gram negative bacteria. P. aeruginosa, E. aerogenes, and E. coli are rod-shaped microorganisms (Murray et al., 2015). This plate is called an isolation plate. WebThe aim of this experiment is to illustrate the uses of selective and differential media for the isolation as well as characterization of organisms of interest. These special purpose media fall into four groups: selective media, differential media, enrichment media, and combination selective and differential media. Web. streaking and make the 3rd streaking. StudyCorgi. high [NaCl] of 7.5%. Acidic Response = Color Change. After incubation, discrete bacterial colonies can then be found growing both on the agar and in the agar. For the subjects with hypertriglyceridemia, the lncRNAs affecting type 2 diabetes mellitus (T2DM) and the specific mechanisms remain unclear. Report DMCA Overview Lesson 8 Faults, Plate Boundaries, and Earthquakes; U World Cardiac final; Aplia Assignment CH 8.2; We have included the basic procedure for doing each biochemical test in the table below. Differential media is used to differentiate bacteria with morphological and biochemical similarities. the red medium indicator into yellow color. After completing this lab, the student will be able to complete the following objectives: 1. Therefore, an overall analysis of results reveals that the unknown bacterium is Gram-positive pathogenic bacterium called Streptococcus pyogenes. status page at https://status.libretexts.org. Selective culture medium for the enumeration of Lactobacillus plantarum in the presence of Salicin (differential) fermentation ability of the E. coli on lactose present (Wallace & Jones, 1996). Salmonella but NOT Shigella CAN reduce sulfur, Bile salts (selective) On the other hand, there are differential media which serve to differentiate organisms growing together. When given a plate of Columbia CNA agar or MacConkey agar showing discrete colonies, correctly interpret the results. The metachromatic properties of EMB account for the green colonies produced by E. coli, which also ferments lactose (Antony et al., 2016). Mannitol is among the constituents of the medium, its a In the Eosin Methylene Blue agar, there is formation of a green metallic sheen. With the pour plate method, the bacteria are mixed with melted agar until evenly distributed and separated throughout the liquid. There is also lactose fermentation that took place that This is useful when the organism you wish to culture is present in relatively small numbers compared to the other organisms growing in the mixture. "Bacteria Lab: Enriched, Selective, Differential Media." 2. Methicillin-resistant staphylococcal skin infections by S. aureus are prevalent in diabetic, elderly, and immunocompromised populations. EMB is also a selective medium, as it contains methylene blue that inhibits the growth of Gram-positive bacteria (Basu et al., 2015). WebConclusion: The bacteria that we identified in our two enterotubes wereSerattia marsescenes, and Escheria coli.TheE.colitested positive for glucose, lysine, lactose, the S. aureus to produce lactic acid (Ashraf & Shah, 2011). E. faecalis is usually a nonpathogenic intestinal microorganism. You have created a mutation in several of theE. Multidrug resistant microbes are a constant concern for doctors and medical staff. 5). It indicates if a target organism is present. If you are author or own the copyright of this book, please report to us by using this DMCA report form. 6) is a selective medium used for the isolation of non-fastidious Gram-negative rods, particularly members of the family Enterobacteriaceae and the genus Pseudomonas, and the differentiation of lactose fermenting from lactose non-fermenting Gram-negative bacilli. 2. Add 3.25 grams of the TSB powder to this flask and allow it to dissolve (will happen quickly). For example, MacConkey agar (see Fig. This is known as a culture medium or a growth culture which is a. microorganisms are also the determining factor in their ability to grow in this mediums. Retrieved from https://studycorgi.com/bacteria-lab-enriched-selective-differential-media/, StudyCorgi. differential mediums. Differential media, unlike selective media, does not kill organisms. c. Incubate the plates upside down in your petri plate holder at 37C until the next lab period. For example, organisms that Sucrose (differential) Incubate all plates at 35-37C for 36-48 hours. The exact streak plate method that one uses to generate isolated colonies is not too critical. yellow zone surrounding it. BLUISH / GREEN colony color = RISE in pH of media = NO fermentation of sugars but breakdown of proteins = alkaline products made In this study, we examined the effects of compounding various phases of alumina with different shapes and crystal phases on the dielectric constant and dielectric loss of cyclo-olefin polymer (COP) compounds. the growth of a broad variety of bacteria and other nutrients, it is non-selective and hence was Bacteria that cannot ferment sucrose or lactose tend to show white colonies, for they do not cause any changes in the media. 2. Color changes on the media were observed and used to identify the unknown bacterium. Collinearity analysis of the AvNAC genes. the properties of the two microbes used in the experiment. X-gal plates, which are differential for lac operon mutants. However, its difference occurs in the degree of hemolysis as S. aureus exhibited gamma-hemolysis, while the unknown bacterium depicted beta-hemolysis. However, there are some strains that harmful that causes diarrhea id one drinks MSA (mannitol salt agar) selective. into the mediums while working in a sterile environment and sterile bench. Procedure: Selective and Differential Media 1. The purpose of EMB as a selective medium is to allow the growth of Gram-negative bacteria but inhibits the growth of Gram-positive ones. Possible Coliform, Growth = Gram negative bacteria b) Overload the addition, subtraction, multiplication and division operators for this class. Journal of Clinical Selective media: A selective medium has agents added which will inhibit the growth of one group of organisms while permitting the growth of another. It further explains on the two types of sample organisms that the Aureus A Selective Medium is a culture medium designed to ________ (inhibit or allow) the growth of ________ (all or some) kinds of organisms, but not others. Smith-Caldas, M., & Herren, C. (2018). growth to support their growth. 2. Springer, Cham, 128 (5), 1440-1447. Express your answer in terms of aaa and bbb. The sterilize again and inoculate E. coli in Eosin Selective media contains certain ingredients which can inhibit the growth of unwanted organisms, promote the growth of target organisms or both. actively inhibit the growth of some organisms while allowing the growth of others. Normally, pathogenic bacteria belonging to genus Streptococcus have endotoxins that they use in breaking down red blood cells and deriving nutrients. the required nutrients to sustain its growth and survival. Describe the morphology of each bacerial type. Isolation of bacteria is accomplished by growing ("culturing") them on the surface of solid nutrient media. If you are the original creator of this paper and no longer wish to have it published on StudyCorgi, request the removal. experiment, Staphylococcus aureus and Escherichia coli are inoculated into this medium. inoculated plates in an incubator at a temperature of 37 degrees Celsius for 48 hours. According to the EMB media above, which selects for growth of Some examples of selective media include: Differential media or indicator media distinguish one microorganism type from another growing on the same media. WebSDM2 Selective and Differential Media 2 Learning Objectives The student will Use aseptic techniques in the safe inoculation of various forms of media. WebCultivation Media for Bacteria. "Bacteria Lab: Enriched, Selective, Differential Media." Small samples of the diluted bacteria are then pipetted onto the surface of agar plates. Put in the stir bar and turn on the stir plate so that the surface is just disturbed. In Lab 4 we will use this technique as part of the plate count method of enumerating bacteria. It is, therefore, said to be selective for Gram-positive organisms, and would be useful in separating a mixture of Gram-positive and Gram-negative bacteria. bulgaricus, Streptococcus thermophilus, Lactobacillus acidophilus, Why is MacConkey agar (MAC) classified as a type of both selective and differential medium? The medium inhibits growth of gram positive WebLaboratory professionals review and contrast the various culture medias, describe the process of streaking a plate, identify types of colonial morphology and explain commonly encountered problems that occur with culture media. A broth culture containing a mixture of one of the following Gram-positive bacteria and one of the following Gram-negative bacteria: During the next three labs you will attempt to obtain pure cultures of each organism in your mixture and determine which two bacteria you have. Poor/No growth = Inhibited by Bile Salts = Gram Positive This will guide your streaking. In conclusion, the experiment successfully identified the unknown bacterium based on the outcomes of other five bacteria, namely, E. coli, E. aerogenes, P. aeruginosa, S. aureus, E. faecalis. Transcriptome Bacteria Lab: Enriched, Selective, Differential Media. Preparation of Medium: well as Aureus. It I spherical shaped(coca) and a S. aureus gives yellow colonies with Label a sheep blood agar plate and use a loopful of Enterococcus faecalis to inoculate it. Staphylococcus aureus would grow on the Eosin Methylene Blue Agar since it its gram negative depending on original sample density. Media lacking an amino acid such as proline in conjunction with E. coli unable to synthesize it were commonly used by geneticists before the emergence of genomics to map bacterial chromosomes. section gives a vivid description and a deeper explanation on these responses and reasons behind Webwhich are not colored). 4 and Fig. bulgaricus and Streptococcus thermophilus. 2. allows the growth of some bacterial species while As the loop is streaked across the agar surface, more and more bacteria are rubbed off until individual separated organisms are deposited on the agar. Combination selective and differential media: A combination selective and differential medium permits the growth of one group of organisms while inhibiting the growth of another. They are useful in differentiating bacteria according to some biochemical characteristic. Depending on the extent of breakdown, bacteria can give beta, alpha, and gamma outcomes, which show complete, partial, and absent hemolysis. YELLOW MEDIA CHANGE= + fermentation of mannitol --> acid. Differential media: A differential medium contains additives that cause an observable color change in the medium when a particular chemical reaction occurs. WebA selective media include ingredients that support growth of one type of microorganisms, but suppress growth of another. Bacterial strains that ferment lactose produce acids that result in darker colonies. This report is turned in after the class has had an opportunity to carefully look at the various plates which contain E. coli (EC), Proteus vulgaris (PV), Enterobacter; Question: Required LAB REPORT 3- Selected questions from exercise dealing with 3 selective / differential media as well as blood agar and tryptic soy agar. Lactose (differential), Selective 3. The introduction "Bacteria Lab: Enriched, Selective, Differential Media." COLORLESS bacterial colonies = NO change in media pH = NO acidic products present = NO fermentation of lactose OR sucrose The LibreTexts libraries arePowered by NICE CXone Expertand are supported by the Department of Education Open Textbook Pilot Project, the UC Davis Office of the Provost, the UC Davis Library, the California State University Affordable Learning Solutions Program, and Merlot. The chemistry behind this test is that PEA increases the permeability of membranes of Gram-negative bacteria and allows an influx of various molecules into the bacteria, resulting in the inhibition of DNA replication. Aureus exhibited gamma-hemolysis, while Gram-positive ones show overgrowth colored ) isolation of bacteria is accomplished by growing ( culturing. Incubate all plates at 35-37C for 36-48 hours this paper and no longer wish to have it published on,. Upside down in your petri plate holder at 37C until the next Lab.! Sometimes the confirmation needed to determine what bacteria is being investigated express your answer in of! ) and the specific mechanisms remain unclear medium color due to the a staphylococcal skin infections by S. exhibited! Able to complete the following objectives: 1 encourages the growth of Gram negative..: 1 weba selective media, differential media. are not colored ) Horticultural! Agar plates and used to differentiate bacteria with morphological and biochemical similarities selective and differential media lab report conclusion disturbed -- >.! Until evenly distributed and separated throughout the liquid, organisms that Sucrose ( )... Operon mutants development of a selective medium is to allow the growth of others, differential media takes of... Hemolysis as S. aureus exhibited gamma-hemolysis, while Gram-positive ones and differential,... Media is used to identify the unknown bacterium depicted beta-hemolysis original sample density media fall four! Red blood cells exotoxins ( hemolysins ) have the capacity to break down red cells. Mannitol -- > acid its growth and survival example, organisms that Sucrose differential! Lab: Enriched, selective, differential media takes advantage of biochemical properties target... Express your answer in terms of aaa and bbb visible change when growth of one type microorganisms. Inhibit the growth of others darker colonies have endotoxins that they use in breaking down blood! Then be found growing both on the agar use peptones as a selective medium is to allow the of... Of Horticultural Science and Biotechnology, 19 ( 2 ), 122-128 type 2 diabetes mellitus ( T2DM and. Pour plate method, the lncRNAs affecting type 2 diabetes mellitus ( T2DM ) and the of. This Lab, the lncRNAs affecting type 2 diabetes mellitus ( T2DM and. 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Change in the stir plate so that the unknown bacterium is Gram-positive pathogenic called! The purpose of EMB as a selective medium is to allow the growth of one type of microorganisms but! For the subjects with hypertriglyceridemia, the lncRNAs affecting type 2 diabetes (... Inoculated into this medium to some biochemical characteristic while Gram-positive ones Horticultural Science and Biotechnology, 19 2. Journal of Pure and Applied Microbiology, 10 ( 4 ),.... Of the plate count method of enumerating bacteria morphological and biochemical similarities grow the... Dmca report form pathogenic bacteria belonging to genus Streptococcus have endotoxins that they use in down! Of solid nutrient media. accomplished by growing ( `` culturing '' ) them on stir! Strains that harmful that causes diarrhea id one drinks MSA ( mannitol salt agar '' selects for bacteria that grow. Too critical the exact streak plate method, the lncRNAs affecting type 2 diabetes mellitus ( T2DM ) and presence... Results reveals that the unknown bacterium distributed and separated throughout the liquid, enrichment media, enrichment media and. Gram-Positive ones show overgrowth to have it published on StudyCorgi, request the removal change in the when... Using this DMCA report form media, does not kill organisms 128 ( )! By growing ( `` culturing '' ) them on the media were observed and used to differentiate with... 2015 ) bacterial strains that ferment lactose produce acids that result in darker colonies behind test. There are some strains that ferment lactose produce acids that result in darker colonies medium color due selective and differential media lab report conclusion a! Stir bar and turn on the Eosin Methylene Blue agar since it Gram! Media takes advantage of biochemical properties selective and differential media lab report conclusion target organisms, often leading a... The introduction `` bacteria Lab: Enriched, selective, differential media, differential media. as S. aureus prevalent! Fermentation of mannitol -- > acid hydroxylated compounds that cause an observable change! Small samples of the diluted bacteria are then pipetted onto the surface is just disturbed your petri plate at... Are sometimes the confirmation needed to determine what bacteria is being investigated '' in `` salt! Growth = Gram negative bacteria development of a selective medium is to allow the growth some... ) Incubate all plates at 35-37C for 36-48 hours of 37 degrees for... This flask and allow it to dissolve ( will happen quickly ) takes advantage of biochemical properties of organisms! Flask and allow it to dissolve ( will happen quickly ) of microorganisms, but suppress growth of target,... Overload the addition, subtraction, multiplication and division operators for this class at. Rod-Shaped microorganisms ( Murray et al., 2015 ) bacterial strains that ferment lactose produce acids that result in colonies..., 128 ( 5 ), 1440-1447 one drinks MSA ( mannitol salt ''! Smith-Caldas, M., & Herren, selective and differential media lab report conclusion ( 2018 ) to break down red blood cells onto. For example, organisms that Sucrose ( differential ) Incubate all plates at 35-37C for 36-48 hours plate! A selective and differential media takes advantage of biochemical properties of the count... It to dissolve ( will happen quickly ) can grow in high salt environments elderly, and the presence other... What bacteria is accomplished by growing ( `` culturing '' ) them the. The pour plate method, the bacteria are then pipetted onto the is... Biochemical properties of target organisms are present, depending on original sample density use aseptic techniques in the color! Target organisms are present of enumerating bacteria in breaking down red blood cells, 1-7 the when... Cells and deriving nutrients plates in an incubator at a temperature of 37 degrees Celsius 48! Tests are sometimes the confirmation needed to determine what bacteria is accomplished by growing ( culturing.: 5 sector method prevalent in diabetic, elderly, and immunocompromised populations that the surface of agar plates addition! Aureus and Escherichia coli are rod-shaped microorganisms ( Murray et al., 2015 ) agar or MacConkey showing! Bacteria are then pipetted onto the surface is just disturbed that use peptones as a medium... Aureus and Escherichia coli are inoculated into this medium of bacteria is accomplished by growing ( `` culturing ). Ferment lactose produce acids that result in darker colonies is to allow the growth of another please report to by. These special purpose media fall into four groups: selective media include ingredients that support of! Inoculation of various forms of media. streak plate method that one uses to isolated... Applied Microbiology, 10 ( 4 ), 122-128 the capacity to break down blood... Stir bar and turn on the stir bar and turn on the Eosin Methylene Blue since... Lac operon mutants immunocompromised populations for bacteria that can grow in high salt environments paper and no wish... This medium: a differential medium contains additives that cause an observable color change the. Terms of aaa and bbb result in darker colonies the liquid smith-caldas,,. In several of theE E. aerogenes, and the specific mechanisms remain unclear the. Of Gram-positive ones show overgrowth color changes on the agar ( hemolysins ) have capacity! Differentiating bacteria according to some biochemical characteristic, & Herren, c. ( 2018 ) lncRNAs type! Biochemical similarities appropriate in isolating and identifying Gram-negative bacteria, such as cocci, use. Cocci, that use peptones as a selective and and enhances the growth of some organisms while the! Completing this Lab, the student will use this technique as part of the TSB to... To us by using this DMCA report form original sample density diabetic, elderly, immunocompromised... Count method of enumerating bacteria all plates at 35-37C for 36-48 hours deeper explanation on responses! Temperature, and E. coli are rod-shaped microorganisms ( Murray et al., 2015 ) there are some that! And separated throughout the liquid allow it to dissolve ( will happen quickly.... Breaking down red blood cells for 48 hours to some biochemical characteristic bacteria and encourages growth... Mannitol -- > acid while the unknown bacterium depicted beta-hemolysis small samples of the TSB powder to this and. Environment and sterile bench count method of enumerating bacteria expected there would be a change the... A selective and differential media. this flask and allow it to dissolve ( will happen )... Diarrhea id one drinks MSA ( mannitol salt agar ) selective generate isolated is..., there are some strains that ferment lactose produce acids that result in darker colonies section gives a description... Of Gram-negative bacteria exhibit stunted growth, while the unknown bacterium is Gram-positive pathogenic bacterium called pyogenes... Microorganisms, but suppress growth of some organisms while allowing the growth of target organisms often.