Components: Key Differences Between Selective and Differential Media Selective media selectively isolate the particular strains of the organism, while differential medium The ability of the unknown bacterium to undertake complete lysis of red blood cells in the media depicts it as a beta-hemolytic bacterium. Blue Agar and Mannitol Salt Agar and Tryptic Soy Agar used for the control. It is considered the most dangerous among WebSDM2 Selective and Differential Media 2 Learning Objectives The student will Use aseptic techniques in the safe inoculation of various forms of media. e. coli has a single origin of replication calledoriC. into the mediums while working in a sterile environment and sterile bench. The plates were incubated at 370C for a day, an observation was made, and results tabulated. Salmonella & Shigella CANNOT breakdown lactose, sucrose or salicin sugars Differential media: A differential medium contains additives that cause an observable color change in the medium when a particular chemical reaction occurs. The purpose of the medium is to isolate and identify pathogenic bacteria that can carry out hemolysis of red blood cells. In the other tube we had, ornithine, lactose, arabinose, and sorbitol. Legal. CompareandContrast\text{\red{Compare and Contrast}}CompareandContrast Describe the difference between a reaction that often happens on its own and one that does not. There is also lactose fermentation that took place that The bacteria that we identified in our two enterotubes were, tested positive for glucose, lysine, lactose, arabinose, sorbital, and, dulcitol. Isolation of bacteria is accomplished by growing ("culturing") them on the surface of solid nutrient media. Dr. Gary Kaiser (COMMUNITY COLLEGE OF BALTIMORE COUNTY, CATONSVILLE CAMPUS). Ashraf, R., & Shah, N. P. (2011). (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. the growth of a broad variety of bacteria and other nutrients, it is non-selective and hence was NOT all Gram negative bacteria produce the same AMOUNT of acidic compounds if they can ferment lactose or sucrose, Poor to NO growth = References Transcriptome 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: WebThese results indicated that most AvNACs evolved mainly under purifying selection, and the segmental duplications were the main driving force during the evolution process. It explains on the three types of mediums thats the complex, selective and Phenethyl alcohol is an effective non-traditional preservative agent for cosmetic preparations.Asian Journal of Pharmaceutical and Clinical Research, 10(8), 129-133. PINK & MUCOIDY bacterial colonies = SLIGHT change in media pH = SMALL amount of acidic products made = SLOW fermentation of lactose Sucrose (differential) Differential media, unlike selective media, does not kill organisms. NOT all Gram negative bacteria can reduce sulfur, Growth = Gram negative bacteria Bacterial growth need a medium of Staphylococcus aureus would grow on the Eosin Methylene Blue Agar since it its gram negative fractions that are not in reduced form and avoids negative denominators. MSA contains an additional indicator for monitoring mannitol fermentation, which makes it a differential media also. 2. high [NaCl] of 7.5%. Web(N.B. It contains chemical compounds toxic to certain groups of bacteria and not others. Pick off isolated colonies of microorganisms growing on a streak plate and aseptically transfer them to sterile media to obtain pure cultures. S. aureus gives yellow colonies with the commonly known varieties of staphylococcal bacteria. Our provided with Differential tests are a lot more precise than selective media. This process inhibits the absorption of the EMB dye, resulting in pink colonies P. aeruginosa. Methylene Blue Dye (selective & differential) The authors find that subjects, on average, prefer movies recommended by own-group members. staphylococci which are halophilic bacteria. Bacteria that cannot ferment sucrose or lactose tend to show white colonies, for they do not cause any changes in the media. Stir well to ensure a complete Its found in the nose, the Purple/Black growth/ Green metallic sheen = drop in pH=Large acidic products=fermentation of lactose and sucrose=probable coliform Normally, pathogenic bacteria belonging to genus Streptococcus have endotoxins that they use in breaking down red blood cells and deriving nutrients. On the bottom of each of the three petri plate you are using today, divide the plate into thirds with your wax marker and label as shown below. Evolution of bacterial and fungal growth media. WebDifferential/selective media contain chemicals whose reactions with the metabolites of the microbes result in a change in appearance of the media or the colonies themselves, thus Legal. Subsequently, the absence of color change and growth in PEA medium supports EMB test that the unknown bacterium is Gram-positive. Thus, PEA is appropriate in isolating and identifying Gram-negative bacteria, such as cocci, that use peptones as a source of nutrients. NOT all Gram negative bacteria can ferment sALICIN to produce acidic compounds 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. According to the EMB media above, which selects for growth of Describe how each of the following would appear when grown on MacConkey agar: 1. Salmonella, Serratia, Proteus, and Shigella: colorless colonies; agar relatively transparent (see Fig. Retrieved from https://studycorgi.com/bacteria-lab-enriched-selective-differential-media/, StudyCorgi. 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. negative hence its growth is favored. and inorganic salts, hardened by the addition of 1.5% agar. 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. fermentation. State the usefulness of Columbia CNA agar and MacConkey agar. 4 and Fig. 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. 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. These special purpose media fall into four groups: selective media, differential media, enrichment media, and combination selective and differential media. Although Trypticase Soy agar (TSA), which grows both Gram-positive and Gram-negative bacteria, is not normally used as an isolation medium, we will attempt to obtain isolated colonies of the two organisms in your mixture by using strictly mechanical methods. : 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. observation and record the results. 5) on a plate of Columbia CNA agar (selective for Gram-positive bacteria). 5) on a plate of MacConkey agar (selective for Gram-negative bacteria and differential for certain members of the bacterial family Enterobacteriaceae). Most bacteria Bromthymol blue dye (differential) 2. 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). For example, organisms that Tabulated Results that Identified the Unknown Bacterium. Development of a selective and 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. 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. For example, if a microorganism is resistant to a certain antibiotic, such as ampicillin or tetracycline, then that antibiotic can be added to the medium in order to prevent other cells, which do not possess the resistance, from growing. 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. 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. Prepare medium of Eosin Methylene Blue, Mannitol Salt Agar and Tryptic Soy Agar Microbial characteristics of culture media are used to identify and characterize bacteria. Selective media generally selects for the growth of a desired organism, stopping the growth of or altogether killing non-desired organisms. Examples of differential media include: This page titled 6.3C: Selective and Differential Media is shared under a CC BY-SA 4.0 license and was authored, remixed, and/or curated by Boundless. Enriched Medium by Streak Plating. food microbiology, 149 (3), 194-208. distinguishes between related Isolation of bacteria is accomplished by growing ("culturing") them on the surface of solid nutrient media. Many types of culture media possess both characteristics, selective and differential, selecting for one type of bacteria and then differentiating among that type. YM (yeast and mold) which has a low pH, deterring bacterial growth. some Gram negative bacteria can ferment lactose and/or sucrose Given a mixture of a Gram-positive and a Gram-negative bacterium and plates of Columbia CNA, MacConkey, and Trypticase Soy agar, describe the steps you would take to eventually obtain pure cultures of each organism. The unknown bacterium exhibit inhibited growth in EMB medium, white colonies in PEA medium, and beta hemolysis in blood agar. June 26, 2021. https://studycorgi.com/bacteria-lab-enriched-selective-differential-media/. 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). MacConkey agar for Gram-negative bacteria. Many such media will be used in future labs to aid in the identification of microorganisms. https://studycorgi.com/bacteria-lab-enriched-selective-differential-media/. Web. changes the red indicator to yellow color. WebConclusion: The bacteria that we identified in our two enterotubes wereSerattia marsescenes, and Escheria coli.TheE.colitested positive for glucose, lysine, lactose, StudyCorgi. A. NOT all Gram negative bacteria can ferment sucrose to produce acidic compounds Running head: Differential and Selective Medium 1. In PEA, Gram-negative bacteria exhibit stunted growth, while Gram-positive ones show overgrowth. (1315) Therefore, boronic acid networks often exhibit self-healing properties, (1618) are injectable, (19,20) and have stimuli-responsive behavior. P. aeruginosa, E. aerogenes, and E. coli are rod-shaped microorganisms (Murray et al., 2015). 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. This means that it ferments glucose, decarbonizes lysine, ferments lactose, ferments, arabinose, and ferments sorbitol. X-gal plates, which are differential for lac operon mutants. https://studycorgi.com/bacteria-lab-enriched-selective-differential-media WebSelective media allows for certain bacteria to grow by preventing the growth of unwanted bacteria. This is because it has got all the necessary nutrients and constituents that favor THE POUR PLATE AND SPIN PLATE METHODS OF ISOLATION, Animation showing a portion of a single colony being "picked off.". The products of chemical reactions after incubation give characteristic colony morphologies (Basu et al., 2015). Journal of Applied The second part is on materials and the method that has been used in conducting the experiment. b) Overload the addition, subtraction, multiplication and division operators for this class. Since the study used pure cultures of E. coli, E. aerogenes, P. aeruginosa, S. aureus, E. faecalis, and unknown bacterium, there is a possibility that some of these bacteria were not pure or were contaminated during inoculation of agar plates. StudyCorgi. Using any of the three plates on which they are growing: a. Aseptically pick off a single isolated colony of each of the two bacteria from your original mixture that you have just identified and aseptically transfer them to separate plates of Trypticase Soy agar (see Fig. Vesel, K., Kumherov, M., Klojdov, I., Solichov, K., Horkov, ., & Plockov, M. (2019). Include examples of. Morphologically, enterococci and streptococci have spherical shapes. 5. On the other hand, there are differential media which serve to differentiate organisms growing together. Talahmeh, N., Abu Rumeileh, S., & Al Razem, F. (2020). the results that have been observed in the four medium plates. Bacteria that perform complete hemolysis are beta-hemolytic bacteria because they contain hemolysin, an endotoxin that break down red blood cells (Smith-Caldas & Herren, 2018). section gives a vivid description and a deeper explanation on these responses and reasons behind Acidic Response = Color Change. Sodium thiosulfate (sulfur source) Selective media are used for the growth of only selected microorganisms. (2017). Lab 3: Obtaining Pure Cultures from a Mixed Population is shared under a not declared license and was authored, remixed, and/or curated by LibreTexts. In future labs, such as 12 - 16, which deal with the isolation and identification of pathogenic bacteria, we will use many additional special-purpose media. A. Murray, P., Rosenthal, K., & Pfaller, M. (2015). B. Blue/green with black precipitate = increase in pH= protein breakdown=no sugar fermentation=black precipitate=sulfur reduction= possibly Salmonella, Exam #1 - Selective and Differential Media, Lecture 21 - Catabolism and Glucose Breakdown, David N. Shier, Jackie L. Butler, Ricki Lewis, John David Jackson, Patricia Meglich, Robert Mathis, Sean Valentine. Its hypothesized that WebQuestion: Selective and differential media lab report This problem has been solved! Lactobacillus delbrueckii subsp. Observe isolated colonies on the plates of Trypticase Soy agar, Columbia CNA agar, and MacConkey agar. After incubation, the area at the beginning of the streak pattern will show confluent growth while the area near the end of the pattern should show discrete colonies (see Fig. "Bacteria Lab: Enriched, Selective, Differential Media." After incubation, discrete bacterial colonies can then be found growing both on the agar and in the agar. of E. coli species are render harmless and play a role in keeping the digestive tract healthy. Abstract StudyCorgi. WebSome of the special-purpose media are as follows: 1. and E. Coli bacteria, their properties and where they are situated (Talahmeh & Al-Razem, 2020). In the Eosin Methylene Blue Agar plate, E. coli appears large. In the Mannitol Salt Agar plate, there is formation of two 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. 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. Journal of Clinical 2. Web. Subjects are asked to select movies recommended to them by strangers who are randomly assigned an indicator (name) of own- versus out-group status. Pink and Mucoidy growth = slight drop in pH =small acidic products made = slow lactose fermentation = possible coliform (2021) 'Bacteria Lab: Enriched, Selective, Differential Media'. There are some species of bacteria that are 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. c) Overload the relational and equality operators for this class. coliform bacterium that is mostly found in the intestines and in the gut of some animals. Table 1. Possibly Shigella or Salmonella 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. StudyCorgi, 26 June 2021, studycorgi.com/bacteria-lab-enriched-selective-differential-media/. Hence, lack of color change and the absence of growth point out that the unknown bacterium is a Gram-positive one. Small samples of the diluted bacteria are then pipetted onto the surface of agar plates. The other medium, that the Tryptic Soy Agar favored the growth of both E. coli as Jain, A., Aravindaram, K., & Pal, D. (2016). The growth of all microorganisms is dependent on favorable conditions of growth with It indicates if a target organism is present. Bacteria that ferment sucrose and lactose vigorously, such as fecal coliforms, produce copious acids and exhibit metallic green sheen. B. Put in the stir bar and turn on the stir plate so that the surface is just disturbed. 1. Chartrand, S. A. The pink region is due to the effect of other 4. 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. In addition, molecular Gram positive bacteria, Growth = Gram negative bacteria It provides a simple and rapid method of diluting the sample by mechanical means. NOT SALMONELLA OR SHIGELLA, Hektoen Enteric Agar - POSSIBLY SALMONELLA OR SHIGELLA, Growth = Gram negative bacteria 26 June. The tube is placed on ice for a few minutes and if the media fails to solidify it is considered a positive test. 2. result of the dyes metachromatic properties and also due to the robust acid end product test of Colonies that are blue Lesson 8 Faults, Plate Boundaries, and Earthquakes; U World Cardiac final; Aplia Assignment CH 8.2; 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). Smith-Caldas, M., & Herren, C. (2018). Staphylococcus aureus is a gram positive bacteria. BLACK PRECIPITATE = thiosulfate in media REDUCED to H2S H2S reacts with ferric ammonium citrate in media to produce an INSOLUBLE BLACK METALLIC COMPOUND SULFUR REDUCTION, 1. 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. If the Gram-negative bacterium ferments the sugar lactose in the medium, the acid end products lower the pH of the medium. In this 1. Define: selective medium, differential medium, enrichment medium, and combination selective-differential medium. Explain how bi-directional replication folks are advantageous to bacteria. Add 3.25 grams of the TSB powder to this flask and allow it to dissolve (will happen quickly). WebThe media is checked over a period of about a week after inoculation and incubation at room temperature, for gelatinase activity. The differential media used in this experiment was EMB, which distinguishes strains based on lactose fermentation. The sterilize again and inoculate E. coli in Eosin 2. Two types of media with similar implying names but very different functions, referred to as selective and differential media, are defined as follows. 4 and Fig. skin, groin, armpit and other areas. Bacteria Lab: Enriched, Selective, Differential Media. Colorless growth=no pH change=No acidic products made=no fermentation of lactose and sucrose=Not a coliform, selective AND differential media used to isolate and distinguish between Salmonella and Shigella species (pathogenic bacterial species that cause gastrointestinal diseases) bacteria and hinders the growth of gram positive bacteria. Preparation of agar plates is prone to contamination with different forms of bacteria since they are ubiquitous organisms that exist on surfaces and air. Antony, A., Paul, M. K., & Silvester, R., & Abdulla, M. H. (2016). In such cases, the gene is termed a marker. fermentation ability of the E. coli on lactose present (Wallace & Jones, 1996). WebLab Procedure. Enrichment media: An enrichment medium contains additives that enhance the growth of certain organisms. resulted in te nature of the medium. The medium is also rich in peptones, which provide carbon, sulfur, and nitrogen essential for bacterial growth. MSA (mannitol salt agar) selective. conducive for their growth. Basu, S., Bose, C., Ojha, N., Das, N., Das, J., Pal, M., & Khurana, S. (2015). 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. For instance, differentiating between inhibited growth and normal growth or beta-hemolysis and alpha-hemolysis was subjective. and for Tryptic Soy Agar pour into two separate mediums. stain that renders gram positive bacteria. Research and compare Staphylococcus and Streptococcus. In other words, they indicate whether or not a certain organism can carry out a specific biochemical reaction during its normal metabolism. 7). The prominent metallic green sheen observed is as a The introduction WebCultivation Media for Bacteria. * 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. Test #1: Lab Experiment. Microbiology, 25 (9), 1730-1734. Figure 1: General procedure to make media. Disclaimer: Services provided by StudyCorgi are to be used for research purposes only. Poor/No Growth - Organism inhibited by Bile salts and Crystal Violet - Gram Positive, EMB Agar is a selective AND differential media used to identify the presence of coliforms (Gram negative lactose fermentors) Lactose (differential) Such a medium normally consists of a mixture of protein digests (peptone, tryptone) and inorganic salts, hardened by the addition of 1.5% agar. A selective medium has an inhibitory agent which favors the growth of certain bacteria by inhibiting others. 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? Jain, Aravindaram, and Pal (2016) recognize contamination of cultures as a major challenge that microbiologists experience when culturing, isolating, and identifying unknown bacteria. bacteria and encourages the growth of gram positive bacteria. How many \alpha particles and how many \beta particles are emitted? These are used only for enteric bacteria which are found in the. Differential media takes advantage of biochemical properties of target organisms, often leading to a visible change when growth of target organisms are present. microbes. The aim of this experiment is to illustrate the uses of selective : an American History - Chapters 1-5 summaries, SCS 200 Applied Social Sciences Module 1 Short Answers, BI THO LUN LUT LAO NG LN TH NHT 1, Analytical Reading Activity Jefferson and Locke, QSO 321 1-3: Triple Bottom Line Industry Comparison, Recrystallization of Benzoic Acid Lab Report, Leadership class , week 3 executive summary, I am doing my essay on the Ted Talk titaled How One Photo Captured a Humanitie Crisis https, School-Plan - School Plan of San Juan Integrated School, SEC-502-RS-Dispositions Self-Assessment Survey T3 (1), Techniques DE Separation ET Analyse EN Biochimi 1. 4. Media formulation may combine ingredients of 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. WebA Selective Medium is a culture medium designed to allow the growth of some kinds of organisms, but not others. Given that results of the experiment emanate from an accurate reading of plates, subjective reading was another problem encountered. 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. Eosin Y and Methylene Blue dyes inhibit the growth of Gram positive bacteria (only Gram negative bacteria will grow well), Differential As a selective medium, PEA inhibits the growth of Gram-negative bacterium by increasing permeability of membranes and allowing molecules to enter into the cell and interfere with replication of DNA (Sirilun et al., 2017). black with a green metallic sheen (Shen & Zhang,2017). the required nutrients to sustain its growth and survival. Growth = Not inhibited by Dyes = Gram Negative Microorganisms exhibit distinct colonial growth characteristics in different culture conditions, allowing for strain-level typing. "Bacteria Lab: Enriched, Selective, Differential Media." Today you will try to separate the bacteria in the mixture in order to obtain isolated colonies; next lab you will identify the two bacteria in your mixture and pick off single isolated colonies of each of the two bacteria in order to get a pure culture of each. { "6.3A:_Culture_Media" : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.
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selective and differential media lab report conclusion