Fill the table about the selective and diferential media 15. Special media chart:MediaWhy do we use itSelective for:Differential for:МАСEMBMSACentrimideTCBSBCYERegan LoweВАРTellurideQuad PlateBBE (anaerobic)LLA (anaerobic)НЕКCINCHOCMTM16. What is an AB toxin – how does it function. We talked about many AB toxins - give 4 examples andhow specifically they work to exert toxigenic effect.

Hello. Since your question has multiple sub-parts, we will solve first three sub-parts for you. If you want remaining sub-parts to be solved, then please resubmit the whole question and specify those sub-parts you want us to solve.Culture media are liquid or solid substrate/preparation used for the growth, transportation, and storage of microbes. An effective culture medium should contain all the essential nutrients needed for the microbial growth. Specialized culture media are required for the identification, isolation, antibiotic sensitivity, analysis of food and water, and industrial microbiology purposes.Depending on the functional types, the culture media can be classified into several types including selective media, enriched media, differential media, and supportive media. The differential media is used for distinguishing between microbes and allows visual identification based on the microbe’s biological characteristics. On the other side, selective media permit the growth of specific microbes and inhibits the growth of other. For example, the gram-positive bacterial growth is inhibited by bile salts and dyes whereas these agents promote the growth of gram-negative cells. Media Why do we use it Selective for: Differential for: MAC The MacConkey is a differential and selective media used for coliform cultivation. The Enterobacteriaceae family members and Pseudomonas can be isolated and differentiated from other bacterial types due to their gram-negative and non-fastidious nature. The MAC media is used for examination of dairy products, food products, isolation of enteric bacteria, differentiation of lactose fermenters from non-fermenters. It is selective for the growth of gram-negative microbes. The crystal violet dye and bile salt inhibit gram-positive bacterial growth and does not have any impact on gram-negative bacterial growth. It is differential for lactose fermentation. The lactose sugar is the carbon source that is fermented by some gram-negative bacterial cells called fermenters and not by others called non-fermenters. Due to fermentation of lactose, acid is produced which causes the pH (potential of hydrogen) indicator to turn red. However, if the bacterium is a non-fermenter then no acid will be produced and the pH indicator will remain colorless. Therefore, colonies formed by fermenters will be pinkish-red and non-fermenters will be colorless. EMB (Eosin methylene blue) agar It is used for the differentiation and isolation of enteric bacteria that have gram-negative cell type. The water quality can be checked with the help of this media by looking for fecal coliform growth. It is selective for the growth of gram-negative bacteria. The selective components are dyes methylene blue and eosin Y that inhibit gram-positive bacterial growth. It is differential for lactose fermentation. If the bacterial cells ferment lactose or any other carbon source then pH of the medium is lowered. At this acidic pH, the two dyes form a purple precipitate. Therefore, lactose fermenters will form colonies having metallic green sheen. However, non-fermenters will form colorless colonies MSA (mannitol salt agar) It is used for the isolation of Staphylococcus aureus from clinical specimen. The testing of dairy products, food products, water, and cosmetic products can be done using this media. It is selective for Staphylococci as it contains a high salt concentration of 7.5% which is inhibitory for the growth of other bacterial cells. It is differential for mannitol fermentation. The pathogenic strains of Staphylococci can ferment mannitol to produce acidic products which convert phenol red (pH indicator) into a yellow colored form. Therefore, mannitol fermenters form yellow colonies.