In such cases, the gene is termed a marker. Explore examples of selective and differential media; Practice Exams. One of the most powerful applications of these types of media is combining both selective and differential characteristics into a single type of media. If so please see the note that follows. 0000000727 00000 n
Differential media. Missed the LibreFest? Selective media refer to a type of growth media that allows the growth of selected microorganisms in the medium. 0000001092 00000 n
Whether you are politically right-sided, left-sided, or not sided at all, this affects what you click on and how you interpret it. Agar-Based, Enriched Media, Enrichment Media, Fastidious Bacteria, Selective Media. Examples of selective media include: Thayer Martin Agar used to recover N. gonorrhoeae contains antibiotics; vancomycin, colistin and nystatin. For example, mannitol salt agar contains a high concentration of sodium chloride that inhibits the growth of most organisms but permits staphylococci to grow. Selective media allows for the growth of one type of bacteria while preventing the growth of another type. Blood agar, EMB agar, and MacConky agar are examples of differential media. Selective media are used for the growth of only selected microorganisms. : The non-selective media on the right allows of the growth of several different bactarial species and is overgrown with bacteria (whitish lines). [ "article:topic", "Selective Media", "Differential media", "authorname:boundless", "showtoc:no", "license:ccbysa" ], https://bio.libretexts.org/@app/auth/2/login?returnto=https%3A%2F%2Fbio.libretexts.org%2FBookshelves%2FMicrobiology%2FBook%253A_Microbiology_(Boundless)%2F6%253A_Culturing_Microorganisms%2F6.3%253A_Culturing_Bacteria%2F6.3C%253A_Selective_and_Differential_Media, 6.3D: Aseptic Technique, Dilution, Streaking, and Spread Plates. Final Exam Intro to Microbiology Status: Not Started. Mannitol Salt medium (MSA) will only grow halophilic (salt-loving) bacteria, such as Staphylococcus & Micrococcus. in addition to the basal medium. Selective medium is designed to suppress the growth of some microorganisms while allowing the growth of others. H\TtMWþþ½Ï¹7"'N$BF RæÜxEj*ñX¹WD3A04Aq1M*¥3vÚaÉI½ië5¥m5
Ehf&JÊ. For example, if the introduction of an antibiotic such as ampicillin destroys or otherwise agitates the growing cells, scientists can reasonably conclude that the cells react adversely to ampicillin. Selective growth media are also used in cell culture to ensure the survival or proliferation of cells with certain properties, such as antibiotic resistance or the ability to synthesize a certain metabolite. Mannitol Salt Agar and Salt Milk Agar used to recover S.aureus contains 10% NaCl. There are many types of media used in the studies of microbes. 1. bacteria that reside in the guts of birds and all mammals (including humans) 2. most well known coliform is E. coli drinking water must be assessed for the presence of coliforms since this is an indicator of fecal contamination 3. Selective media generally selects for the growth of a desired organism, stopping the growth of or altogether killing non-desired organisms. Eosin methylene blue contains dyes that are toxic for Gram-positive bacteria. SELECTIVE MEDIA. 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. many types of selective media that contain indicators to expose differences between organisms. Two types of media with similar implying names but very different functions, referred to as selective and differential media, are defined as follows. As some organisms inhibit or grow faster than others, using selective media may be required. jejuni from fecal or rectal swabs 21. 6.3C: Selective and Differential Media - Biology LibreTexts Selective media are formulated to contain ingredients that inhibit the growth of selected species or categories of bacteria while allowing other organisms to grow. Example of selective media supplemented with dyes:. Selective definition is - of, relating to, or characterized by selection : selecting or tending to select. Other media are more selective for specific organisms. An example of a selective medium is MacConkey agar. Media that inhibit the growth of unwanted microorganisms and support the growth of the organism of interest by supplying nutrients and reducing competition are called selective media. 47 0 obj
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For example, Donald Trump supporters are more likely to scroll past an article with a headline that speaks negatively of him. This type of media is used for the detection of microorganisms and by molecular biologists to detect recombinant strains of bacteria. Therefore, these media contain extra nutrients in the form of egg yolk, blood, serum, etc. Examples of media with altered pH:. Summary – Selective vs Differential Media For example, NaCl media selects for halophiles (salt lovers) versus non-halophiles. MacConkey agar media contains bile salt and less selective for the isolation of different members belonging to the Enterobacteriacea family. Media can be Selective and Differential. For example… X-gal plates, which are differential for lac operon mutants. These formulations may include antibiotics which inhibit the growth of gram positive bacteria or gram negative bacteria. 0000001374 00000 n
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