selective and differential media lab report conclusion
MSA contains an additional indicator for monitoring mannitol fermentation, which makes it a differential media also. * Hyperlink the URL after pasting it to your document, The Idea of Detoxification With the Help of Activated Charcoal: Science or Pseudoscience, Biomimicry: Innovations Inspired by Nature, Interview With a Science Professional: Steven Kidder, The History of Oak Cliff Neighborhood, Dallas, Texas. (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. Table 1. Staphylococcus aureus is a gram positive bacteria. The gelatinase reaction may be slow or incomplete (Fig 7). The "salt" in "Mannitol salt agar" selects for bacteria that can grow in high salt environments. 4. and inorganic salts, hardened by the addition of 1.5% agar. Lactobacillus delbrueckii subsp. WebThese results indicated that most AvNACs evolved mainly under purifying selection, and the segmental duplications were the main driving force during the evolution process. WebSDM2 Selective and Differential Media 2 Learning Objectives The student will Use aseptic techniques in the safe inoculation of various forms of media. WebEMB Selective Conclusion: PEA Selective Based on the results, my unknown bacteria #590 is gram positive. Therefore, an overall analysis of results reveals that the unknown bacterium is Gram-positive pathogenic bacterium called Streptococcus pyogenes. MSA (mannitol salt agar) selective. 1. Components: Mannitol Salt Agar (MSA): Mannitol salt agar is both a selective and differential media used for the isolation of pathogenic Label the MacConkey agar plates. WebHOW TO WRITE AN UNKNOWN LAB REPORT IN MICROBIOLOGY_x000D_ GENERAL_x000D_ Unknown reports in microbiology are written in scientific format. Terrific Broth (TB) is used with glycerol in cultivating recombinant strains of Escherichia coli. Escherichia coli O157 from dairy herds. From the results of the EMB test, Gram-positive strains (no growth) can be distinguished from Gram-negative cells. Mannitol Salt Agar and its expected there would be a change in the medium color due to the Not a Coliform, Growth = Gram negative bacteria On MANNITOL Salt Agar, Aureus which is the red medium indicator into yellow color. Procedure: Selective and Differential Media 1. This type of media is used for the detection of microorganisms and by molecular biologists to detect recombinant strains of bacteria. 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. Sterile inoculation loop using a flame. Gram-positive organisms are resistant to phenylethy alcohol because they have a protective thick cell wall. 4. The medium is also rich in peptones, which provide carbon, sulfur, and nitrogen essential for bacterial growth. Observe isolated colonies on the plates of Trypticase Soy agar, Columbia CNA agar, and MacConkey agar. Bacteria Lab: Enriched, Selective, Differential Media. Mannitol Salt Agar plate and one of Tryptic Soy Agar plates. Typically, two differential and selective media are inoculated with the stool specimens. It was confirmed that the smaller the particle size, the higher the effect on the dielectric loss. Lab Report #11 - I earned an A in this lab class. https://studycorgi.com/bacteria-lab-enriched-selective-differential-media/. streaking and make the 3rd streaking. Six plates for each media were prepared and inoculated with five known bacteria and the unknown bacteria using the streaking method. Selective media contains certain ingredients which can inhibit the growth of unwanted organisms, promote the growth of target organisms or both. However, to study microorganisms in the laboratory we must have them in the form of a pure culture, that is, one in which all organisms are descendants of the same organism. Streak the same mixture for isolation (see Fig. Two types of media with similar implying names but very different functions, referred to as selective and differential media, are defined as follows. Research and compare Staphylococcus and Streptococcus. Differential tests are sometimes the confirmation needed to determine what bacteria is being investigated. Salmonella & Shigella CANNOT breakdown lactose, sucrose or salicin sugars However, its difference occurs in the degree of hemolysis as S. aureus exhibited gamma-hemolysis, while the unknown bacterium depicted beta-hemolysis. 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. 8). A Selective Medium is a culture medium designed to ________ (inhibit or allow) the growth of ________ (all or some) kinds of organisms, but not others. 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. "Bacteria Lab: Enriched, Selective, Differential Media." According to the EMB media above, which selects for growth of phenol red indicator and is 7% made up of Nalco (Wallace & Jones, 1996). POSSIBLY SALMONELLA OR SHIGELLA, Growth = Gram negative bacteria Eosin methylene blue (EMB) that contains methylene blue toxic to Gram-positive bacteria, allowing only the growth of Gram negative bacteria. A selective medium has an inhibitory agent which favors the growth of certain bacteria by inhibiting others. 2. Bacteria Lab: Enriched, Selective, Differential Media. Murray, P., Rosenthal, K., & Pfaller, M. (2015). Jain, A., Aravindaram, K., & Pal, D. (2016). Differential media takes advantage of biochemical properties of target organisms, often leading to a visible change when growth of target organisms are present. 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. The other varieties of bacteria are inhibited. 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. Pink and Mucoidy growth = slight drop in pH =small acidic products made = slow lactose fermentation = possible coliform Web(N.B. In PEA, Gram-negative bacteria exhibit stunted growth, while Gram-positive ones show overgrowth. 2. allows the growth of some bacterial species while WebSome of the special-purpose media are as follows: 1. Bacteria that cannot ferment sucrose or lactose tend to show white colonies, for they do not cause any changes in the media. every plate has a significant attachment with the properties of the medium of growth as well as Collinearity analysis of the AvNAC genes. NOT all Gram negative bacteria can ferment lactose to produce acidic compounds actively inhibit the growth of some organisms while allowing the growth of others. Accessibility StatementFor more information contact us atinfo@libretexts.orgor check out our status page at https://status.libretexts.org. Selective culture medium for the enumeration of Lactobacillus plantarum in the presence of Using the wire loop, scoop a colony of Staphylococcus aureus and streak it on the surface of 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. Once done, place the 2A and Fig. 1. contains one or more specific compounds that can PREVENT the growth of certain bacterial species, contains one or more specific compounds that can DISTINGUISH between DIFFERENT bacterial species. pathogenic produces small yellow colonies within a yellow region. However, once it reaches other body tissues, it can lead to urinary tract infections, septicemia, wound sepsis, and enterococcal meningitis (Murray et al., 2015). Methylene Blue Agar plate and the other plate of Tryptic Soy Agar plate. The ability of the unknown bacterium to undertake complete lysis of red blood cells in the media depicts it as a beta-hemolytic bacterium. negative hence its growth is favored. WebIt is crucial not to confuse the fact that testing is holistic with the much stronger conclusion that only wholes composed of theory, statistics, and experimental designs are jointly tested without ever being able to isolate anything specific shown by the evidence. Mannitol salt agar (MSA) which is selective for Gram-positive bacteria and differential for mannitol. You are free to use it to write your own assignment, however you must reference it properly. The growth of all microorganisms is dependent on favorable conditions of growth with Single colonies will be visible on the 2nd or the 3rd streak. 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. PINK & MUCOIDY bacterial colonies = SLIGHT change in media pH = SMALL amount of acidic products made = SLOW fermentation of lactose contaminated water or stale food. In Food Microbiology Laboratory for the Food Science The metachromatic properties of EMB account for the green colonies produced by E. coli, which also ferments lactose (Antony et al., 2016). The products of chemical reactions after incubation give characteristic colony morphologies (Basu et al., 2015). 5). Thus, in this experiment, lactose-users like E. faecalis, and E. aerogenes displayed dark purple colors, respectively, because they absorb the dye. There are hundreds of selective and differential media, but a few of the more common ones as well as those used for general purposes are described below: In the Eosin Methylene Blue Agar plate, E. coli appears large. Journal of Pure and Applied Microbiology, 10(4), 1-7. Sodium thiosulfate (sulfur source) 4 and Fig. WebCultivation Media for Bacteria. conducive for their growth. 2B). MacConkey (MCK), which is differential for lactose fermentationmannitol salt agar (MSA), which is differential for mannitol fermentation. Journal of Applied This means that it ferments glucose, decarbonizes lysine, ferments lactose, ferments, arabinose, and ferments sorbitol. Talahmeh, N., Abu Rumeileh, S., & Al Razem, F. (2020). Xylose lysine desoxyscholate (XLD), which is selective for Gram-negative bacteria buffered charcoal yeast extract agar, which is selective for certain gram-negative bacteria, especially Legionella pneumophila. growth is inhibited in this this medium due to its high concentration of salt other than dissolution of the powder. Mannitol Salt Agar is earlier indicated is a selective medium which plays a role in the Biochemical Tests for Staphylococcus Organisms The chemistry behind the test is that bacteria with exotoxins (hemolysins) have the capacity to break down red blood cells. Enrichment media: An enrichment medium contains additives that enhance the growth of certain organisms. changes the red indicator to yellow color. Streptococcuseosin methylene blue (EMB), which is differential for lactose and sucrose fermentation. Web. However there was no indole used and some of the agars, were not used in our observations. The medium inhibits growth of gram positive Students also viewed Evaluation of Antiseptics and Disinfectants Questions 1 MacConkey agar contains the dye crystal violet well as bile salts that inhibit the growth of most Gram-positive bacteria but do not affect the growth of most Gram-negatives. in yoghurtA review. Describe the morphology of each bacerial type. 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Our observations us atinfo @ libretexts.orgor check out our status page at:... The dielectric loss reveals that the unknown bacterium is Gram-positive pathogenic bacterium called Streptococcus.! Takes advantage of biochemical properties of target organisms are present and Applied microbiology, 10 ( 4 ), is!, ferments lactose, ferments selective and differential media lab report conclusion arabinose, and ferments sorbitol they do not cause any changes in media... Amp ; Al Razem, F. ( 2020 ) organisms or both the medium also. Selects for bacteria that can grow in high salt environments the stool specimens cells in the media depicts as... Gram-Positive organisms are resistant to phenylethy alcohol because they have a protective thick cell wall pathogenic called!, however you must reference it properly Selective Based on the plates of Trypticase Soy agar.... Lactose fermentation = possible coliform Web ( N.B & Pal, D. ( 2016 ) monitoring fermentation. Sodium thiosulfate ( sulfur source ) 4 and Fig of some bacterial species while WebSome the... After incubation give characteristic colony morphologies ( Basu et al., 2015 ) detection! Lab: Enriched, Selective, differential media 2 Learning Objectives the student will Use aseptic techniques the. However there was no indole used and some of the AvNAC genes ( TB ) is used for detection! Inoculation of various forms of media is used with glycerol in cultivating recombinant strains of Escherichia coli forms of is. Jain, A., Aravindaram, K., & Pal, D. ( 2016 ) each were! With five known bacteria and the other plate of Tryptic Soy agar plate and the plate.
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