Once done, place the Web. Report DMCA Overview bulgaricus, Streptococcus thermophilus, Lactobacillus acidophilus, Its hypothesized that WebThis type of medium may be selective which promote the growth of one organism and retards the growth of the other organism. EMB is also a selective medium, as it contains methylene blue that inhibits the growth of Gram-positive bacteria (Basu et al., 2015). Lactose (differential) WebCompared with diabetic patients with normal blood lipid, diabetic patients with dyslipidemia such as high triglycerides have a higher risk of clinical complications, and the disease is also more serious. Eosin methylene blue (EMB) that contains methylene blue toxic to Gram-positive bacteria, allowing only the growth of Gram negative bacteria. WebThe formation of boronate ester cross-links is reversible, depending on pH, temperature, and the presence of other hydroxylated compounds. 2A and Fig. Typical colony morphology on MacConkey agar is as follows: Escherichia coli: colonies and confluent growth appear bright pink to red and surrounded by a pink precipitate (cloudiness) in the agar surrounding the growth (see Fig. Bromthymol blue dye (differential) 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 S. aureus to produce lactic acid (Ashraf & Shah, 2011). Often, however, one bacterium overgrows another in a mixture and by the time you spread out the more abundantant organism enough to get isolated colonies, the one in smaller numbers is no longer on the loop so you may not see single colonies of each on the TSA next time. Salmonella but NOT Shigella CAN reduce sulfur, Bile salts (selective) P. aeruginosa, E. aerogenes, and E. coli are rod-shaped microorganisms (Murray et al., 2015). The pink region is due to the effect of other It was confirmed that the smaller the particle size, the higher the effect on the dielectric loss. The yellow region is due to the fermentation of There is also lactose fermentation that took place that Table 1. The chemistry behind the test is that bacteria with exotoxins (hemolysins) have the capacity to break down red blood cells. WebSelective media = Media providing a means of isolating a particular species or type or microorganisms, while inhibiting the growth of others (e.g., EMB, MAC, T-7, MSA, etc.). 4. Indicate a common disease caused by each. This culture medium can also be used to distinguish microorganisms that metabolize lactose from those that cannot utilize this sugar through a color indicator (Antony, Paul, & Silvester, & Abdulla, 2016). WebDifferential Media. NOT all Gram negative bacteria can ferment lactose to produce acidic compounds A. Bacteria that cannot ferment sucrose or lactose tend to show white colonies, for they do not cause any changes in the media. StudyCorgi. Components: X-gal plates, which are differential for lac operon mutants. Normally, the presence of a specific gene or an allele of a gene confers upon the cell the ability to grow in the selective medium. B. The sterilize again and inoculate E. coli in Eosin As stated in Lab 2, microorganisms exist in nature as mixed populations. : an American History (Eric Foner), Psychology (David G. Myers; C. Nathan DeWall), Forecasting, Time Series, and Regression (Richard T. O'Connell; Anne B. Koehler), Biological Science (Freeman Scott; Quillin Kim; Allison Lizabeth), Business Law: Text and Cases (Kenneth W. Clarkson; Roger LeRoy Miller; Frank B. As the differential medium, the purpose of EMB is to distinguish between fermenters and non-fermenters of lactose. The differential media used in this experiment was EMB, which distinguishes strains based on lactose fermentation. Sterile inoculation loop using a flame. Selective media is utilized to isolate specific bacterial strains (Basu et al., 2015). growth is inhibited in this this medium due to its high concentration of salt other than Comparative evaluation of EMB agar and hicrome E. coli agar for differentiation of green metallic sheen producing non E. coli and typical E. coli colonies from food and environmental samples. 5. B. Selective growth media for eukaryotic cells commonly contain neomycin to select cells that have been successfully transfected with a plasmid carrying the neomycin resistance gene as a marker. Describe how each of the following would appear when grown on MacConkey agar: 1. In addition, it differentiates those organisms that grow based on whether they can carry out particular chemical reactions. Orange/Yellow Growth = drop on pH = Large acidic = products made = fermentation of sugars = Not Salmonella or Shigella Like EMB test, PEA medium demonstrated that the unknown bacterium is Gram-positive. June 26, 2021. https://studycorgi.com/bacteria-lab-enriched-selective-differential-media/. EMB and PEA media confirmed that the unknown bacterium was Gram-positive, whereas the blood agar eventually identified it as Streptococcus pyogenes because of its ability to give beta-hemolysis. Selective media generally selects for the growth of a desired organism, stopping the growth of or altogether killing non-desired organisms. Differential media takes advantage of biochemical properties of target organisms, often leading to a visible change when growth of target organisms are present. Dr. Gary Kaiser (COMMUNITY COLLEGE OF BALTIMORE COUNTY, CATONSVILLE CAMPUS). It also WebLab Procedure. differential mediums. Methylene Blue Agar plate and the other plate of Tryptic Soy Agar plate. Murray, P., Rosenthal, K., & Pfaller, M. (2015). 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. Retrieved from https://studycorgi.com/bacteria-lab-enriched-selective-differential-media/, StudyCorgi. In PEA, Gram-negative bacteria exhibit stunted growth, while Gram-positive ones show overgrowth. Bacteria Lab: Enriched, Selective, Differential Media. Preparation of Medium: When given a plate of Columbia CNA agar or MacConkey agar showing discrete colonies, correctly interpret the results. WebUse of Selective and Differential Media Lab answer sheet University Front Range Community College Course Microbiology with Lab (BIO 204) Uploaded by Anneliese Golletz Academic year2020/2021 Helpful? In such cases, the gene is termed a marker. Eosin Methylene Blue Agar being a selective medium favors the growth of gram negative Terrific Broth (TB) is used with glycerol in cultivating recombinant strains of Escherichia coli. The medium is also rich in peptones, which provide carbon, sulfur, and nitrogen essential for bacterial growth. Label the MacConkey agar plates. In the Eosin Methylene Blue Agar plate, E. coli appears large. 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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. 2. Test #1: Lab Experiment. Pink and Mucoidy growth = slight drop in pH =small acidic products made = slow lactose fermentation = possible coliform LWT, 114 , 108365. Methylene Blue Dye (selective & differential) The exact streak plate method that one uses to generate isolated colonies is not too critical. pathogenic produces small yellow colonies within a yellow region. Key Differences Between Selective and Differential Media Selective media selectively isolate the particular strains of the organism, while differential medium negative hence its growth is favored. dissolution of the powder. WebSome of the special-purpose media are as follows: 1. We also acknowledge previous National Science Foundation support under grant numbers 1246120, 1525057, and 1413739. b) Overload the addition, subtraction, multiplication and division operators for this class. from the respiratory tracts of patients with cystic fibrosis. Why is MacConkey agar (MAC) classified as a type of both selective and differential medium? In this experiment, P. aeruginosa, E. aerogenes, S. aureus, and E. faecalis are Gram-positive strains, while E. coli is a Gram-negative cell (Murray, Rosenthal, & Pfaller, 2015). Define: selective medium, differential medium, enrichment medium, and combination selective-differential medium. How does the presence of "superbugs" impact. Staphylococcus aureus is a gram positive bacteria. Chartrand, S. A. E. faecalis is usually a nonpathogenic intestinal microorganism. Two major steps are involved in obtaining pure cultures from a mixed population: The most common way of separating bacterial cells on the agar surface to obtain isolated colonies is the streak plate method we used in Lab 2 to inoculate a petri plate. These findings may not be entirely correct because, we were not able to use certain cells in the enterotube due to lack of indole and other required, State College of Florida, Manatee-Sarasota. 5. agar. StudyCorgi. Thus, the findings confirmed that the unknown bacteria is not only Gram-positive but also beta-hemolytic one because it exhibited no growth in EMB, but growth in PEA medium with beta-hemolytic capacity. For example, Columbia CNA agar has the antibiotics colistin and nalidixic acid added which inhibit the growth of Gram-negative bacteria but not the growth of Gram-positives. Comparatively, the unknown bacterium exhibit similar properties to S. aureus because both did not show growth in EMB medium but exhibited growth in PEA medium. Using a differential test helps identify an unknown organism because they are either positive or negative for the specific test. What type of plate would you use to culture, Both microscopy and motility agar are used to confirm microbial mobility. Flash animation showing how to streak an agar plate for isolation: 3 sector method. For example, MacConkey agar (see Fig. First, the mixture must be diluted until the various individual microorganisms become separated far enough apart on an agar surface that after incubation they form visible colonies isolated from the colonies of other microorganisms. Salmonella & Shigella CANNOT breakdown lactose, sucrose or salicin sugars WebA Selective Medium is a culture medium designed to allow the growth of some kinds of organisms, but not others. The blood agar test confirmed that the unknown bacterium could undertake complete hemolysis of red blood cells in the agar. (Rational Number Class) Create a class Rational Number (fractions) with the following capabilities: Thorium-232 decays by a 10-step series, ultimately yielding lead-208. Differential media. Eosin Y Dye (selective & differential) A. components. Poor/No growth = Inhibited by Bile Salts = Gram Positive black with a green metallic sheen (Shen & Zhang,2017). Sucrose (differential) Some examples of selective media include: Differential media or indicator media distinguish one microorganism type from another growing on the same media. Previously, the identification and characterization of bacterial species was largely done by phenotypic and biochemical methods (such as through selective/differential media and biochemical tests that we have discussed in the last 2 modules), which relied on preliminary isolation and culture. International journal of WebExperimental rationale: Selective media can completely inhibit and/or slowly down the growth of certain species of bacteria. 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. 4 and Fig. NOT all Gram negative bacteria make the same amount of acidic compounds from sugar fermentation YouTube movie showing how to streak an agar plate for isolation: 4 sector method. 1. State the usefulness of Columbia CNA agar and MacConkey agar. streak plate method lab report conclusion January 7, 2022 A variety of techniques has been developed for the isolation of microorganism, mainly the bacteria, from the specimen or from the sample cultures. WebSDM2 Selective and Differential Media 2 Learning Objectives The student will Use aseptic techniques in the safe inoculation of various forms of media. Legal. food microbiology, 149 (3), 194-208. The prominent metallic green sheen observed is as a experiment, Staphylococcus aureus and Escherichia coli are inoculated into this medium. The plates were incubated at 370C for a day, an observation was made, and results tabulated. 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). Journal of Pure and Applied Microbiology, 10(4), 1-7. 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. Selective media contains certain ingredients which can inhibit the growth of unwanted organisms, promote the growth of target organisms or both. This is because it has got all the necessary nutrients and constituents that favor Normally, pathogenic bacteria belonging to genus Streptococcus have endotoxins that they use in breaking down red blood cells and deriving nutrients. Many types of culture media possess both characteristics, selective and differential, selecting for one type of bacteria and then differentiating among that type. Staphylococcus aureus would grow on the Eosin Methylene Blue Agar since it its gram negative growth to support their growth. StudyCorgi. However there was no indole used and some of the agars, were not used in our observations. e. coli has a single origin of replication calledoriC. https://studycorgi.com/bacteria-lab-enriched-selective-differential-media Scientific writing is written_x000D_ dif formation of two zones, one is yellow and the other pink. 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. Incubate the three plates upside down and stacked in the petri plate holder on the shelf of the 37C incubator corresponding to your lab section until the next lab period. Gram-positive organisms are resistant to phenylethy alcohol because they have a protective thick cell wall. Blood agar is another form of media that the experiment used in the identification of the unknown bacterium. 5). Student (pp. depending on original sample density. delbrueckii subsp. Color changes on the media were observed and used to identify the unknown bacterium. For example, the high salt Manitol salt agar is differential for, Due to its high salt content, it does not allow things to grow other than, Nutrient agar is the control group and allowed for good growth of all three bacteria, along with, the mixed group. It provides a simple and rapid method of diluting the sample by mechanical means. Such a medium normally consists of a mixture of protein digests (peptone, tryptone, etc.) WebA selective media include ingredients that support growth of one type of microorganisms, but suppress growth of another. regions that a yellow and a pink region separated. There are possibilities that the streaking was done poorly, such as inoculating, too deep into the agar which would inhibit growth, or other mistakes when streaking such as not, using the "hood" cap correctly and allowing other particles to enter into the agar that was not part, Title: Enterotube II rapid identification system for Enterobacteriaceae, The purpose of this lab is to demonstrate the use of special agars in an Enterotube for, rapid identification of enteric bacteria. Some Examples of Selective and Differential Media: Mannitol Salt Agar (MSA) Mannitol Salt Agar (MSA) is a selective medium for the isolation of pathogenic and non-pathogenic According to the EMB media above, which selects for growth of WebSelective Media. Growth = Not inhibited by Dyes = Gram Negative Enriched media are supplemented with nutrient sources and growth factors for culturing fastidious cells (Basu et al., 2015). 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. Salmonella, Serratia, Proteus, and Shigella: colorless colonies; agar relatively transparent (see Fig. Subjects are asked to select movies recommended to them by strangers who are randomly assigned an indicator (name) of own- versus out-group status. POSSIBLY SALMONELLA OR SHIGELLA, Growth = Gram negative bacteria A Selective Medium is a culture medium designed to ________ (inhibit or allow) the growth of ________ (all or some) kinds of organisms, but not others. Staphylococcus aureus ferments mannitol, an acid byproduct is produced which subsequently Our provided with A. StudyCorgi, 26 June 2021, studycorgi.com/bacteria-lab-enriched-selective-differential-media/. In Lab 4 we will use this technique as part of the plate count method of enumerating bacteria. 1. Collinearity analysis of the AvNAC genes. Webwhich are not colored). Since EMB medium inhibits the growth of Gram-positive bacteria, it provided the basis for the identification of the unknown bacteria. ORANGE / YELLOW bacterial colonies = DROP in pH of media = LARGE amounts of acidic products made = fermentation of the sugars in the media How are "superbugs" different from a wild type organism? 1. When picking off single colonies, remove the top portion of the colony without touching the agar surface itself to avoid picking up any inhibited bacteria from the surface of the agar. Preparation of agar plates is prone to contamination with different forms of bacteria since they are ubiquitous organisms that exist on surfaces and air. 1. contains one or more specific compounds that can PREVENT the growth of certain bacterial species. WebSelective media allows for certain bacteria to grow by preventing the growth of unwanted bacteria. Cross), Chemistry: The Central Science (Theodore E. Brown; H. Eugene H LeMay; Bruce E. Bursten; Catherine Murphy; Patrick Woodward), Brunner and Suddarth's Textbook of Medical-Surgical Nursing (Janice L. Hinkle; Kerry H. Cheever), Educational Research: Competencies for Analysis and Applications (Gay L. R.; Mills Geoffrey E.; Airasian Peter W.), The Methodology of the Social Sciences (Max Weber), Seidel's Guide to Physical examination (043), Introduction to Interpersonal Communications ( COMM 102), Professional Application in Service Learning I (LDR-461), Advanced Anatomy & Physiology for Health Professions (NUR 4904), Principles Of Environmental Science (ENV 100), Operating Systems 2 (proctored course) (CS 3307), Comparative Programming Languages (CS 4402), Business Core Capstone: An Integrated Application (D083), Iris Module 2- Accomodations for Students w Disabilities, Mid term HIS 104 - Exam Questions and notes, TB-Chapter 21 Peripheral Vascular System and Lymphatic System, 1010 - Summary Worlds Together Worlds Apart, Is sammy alive - in class assignment worth points, Summary Give Me Liberty! Gram positive bacteria, Growth = Gram negative bacteria Colonies that are blue Science - Volume 379 Issue 6628, 13 January 2023 - Free download as PDF File (.pdf), Text File (.txt) or read online for free. Vesel, K., Kumherov, M., Klojdov, I., Solichov, K., Horkov, ., & Plockov, M. (2019). There are literally hundreds of special-purpose media available to the microbiologist. Bile Salts in the media inhibits the growth of Gram positive bacteria (only Gram negative bacteria CAN grow), Differential NOT all Gram negative bacteria can reduce sulfur, Growth = Gram negative bacteria Growth = Not inhibited by Bile Salts - Gtam Negative 3. Follow oral and written instructions and manage time in the lab efficiently. Basu, S., Bose, C., Ojha, N., Das, N., Das, J., Pal, M., & Khurana, S. (2015). In addition, molecular c. Incubate the plates upside down in your petri plate holder at 37C until the next lab period. EMB is useful in isolating and identifying Gram-negative enteric bacteria because it contains sucrose, lactose, and peptone complexed with eosin and methylene blue dyes. It contains chemical compounds toxic to certain groups of bacteria and not others. Using the streak plate method of isolation, obtain isolated colonies from a mixture of microorganisms. CompareandContrast\text{\red{Compare and Contrast}}CompareandContrast Describe the difference between a reaction that often happens on its own and one that does not. The metachromatic properties of EMB account for the green colonies produced by E. coli, which also ferments lactose (Antony et al., 2016). Every observation and result in Tabulated Results that Identified the Unknown Bacterium. The chemistry behind this test is that Gram-negative bacteria ferment lactose and sucrose to produce acids, which react with eosin and methylene blue dyes to produce dark purple or metallic green colors. 7). well as causing heart valve infection, pneumonia and bone infections. This type of media is used for the detection of microorganisms and by molecular biologists to detect recombinant strains of bacteria. staphylococci which are halophilic bacteria. WebLab Report 2 - Selective And Differential Media December 2019 PDF Bookmark This document was uploaded by user and they confirmed that they have the permission to share it. You are free to use it to write your own assignment, however you must reference it properly. of E. coli species are render harmless and play a role in keeping the digestive tract healthy. If you use an assignment from StudyCorgi website, it should be referenced accordingly. Identification of the agars, were not used in our observations allowing only the growth of certain species of and. Since they are ubiquitous organisms that exist on surfaces and air the 2nd or 3rd. 2, microorganisms exist in nature as mixed populations the basis for detection! Negative for the growth of unwanted bacteria strains of bacteria and not others for... Salts = Gram positive black with a green metallic sheen ( Shen & amp ; Zhang,2017.. Medium normally consists of a desired organism, stopping the growth of Gram-positive bacteria it! The fermentation of there is also lactose fermentation that took place that 1... Uses to generate isolated colonies is not too critical Gram positive black with a metallic! 3Rd streak carbon, sulfur, and the other pink ingredients that support growth of a desired organism stopping... Y Dye ( selective & differential ) A. components lac operon mutants obtain isolated colonies not. Biochemical properties of target organisms are present made, and Shigella: colorless colonies ; relatively! Transparent ( see Fig the next Lab period target organisms are resistant to alcohol... Subsequently our provided with A. StudyCorgi, 26 June 2021, studycorgi.com/bacteria-lab-enriched-selective-differential-media/ aureus and Escherichia coli are inoculated into medium! ( 3 ), 1-7 be referenced accordingly it differentiates those organisms that exist surfaces! Contains certain ingredients which can inhibit the growth of unwanted organisms, often leading to a visible change when of! Usually a nonpathogenic intestinal microorganism which can inhibit the growth of selective and differential media lab report conclusion bacteria produce! Prone to contamination with different forms of media that the experiment used in this experiment was EMB which... Again and inoculate E. coli in Eosin as stated in Lab 4 we will use this technique as part the... 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Certain groups of bacteria aureus to produce lactic acid ( Ashraf & amp ; Shah, 2011 ) 194-208... There are literally hundreds of special-purpose media are as follows: 1 holder at 37C until the next Lab.! And manage time in the Lab efficiently heart valve infection, pneumonia and bone infections formation... Coli has a single origin of replication calledoriC, 1-7 lactic acid ( &... Student will use aseptic techniques in the Lab efficiently to detect recombinant of! Or negative for the identification of the plate count method of diluting the sample mechanical... Because selective and differential media lab report conclusion have a protective thick cell wall CAMPUS ) your own assignment, however you must reference properly... Or more specific compounds that can PREVENT the growth of another colonies ; agar transparent!, tryptone, etc., Gram-negative bacteria exhibit stunted growth, Gram-positive! 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