Agar are come from huge agar plant know as kelps. Are you kidding Ritesh Sharma 0. I dont know about that but you can add a broad spectrum antibiotic to avoid griwth of bacteria in your plates. Whats the basic defferences between all culture media And which culture media would use for which???? Sir I have used nutrient agar for fungus culture…. Before i use PDA for culture it was gud…. But i found lots of bacterial contamination in my Nutrient agar culture….
Does the composition of beef extract hampers the groeth of fungus and favours bacteria instead. Hello I have a question. If a leg wound is cultured and it is put on a nutrient agar, Selective agar and Differential Agar what are expected to show? I streaked out from sweet potato steep water and I had both red colonies and white colonies that turned nutrient agar kind of green.
Please what kind of organisms are these. They areboth staining gram positive. Basal media 2. Enriched media 3. Selective media 4. Enrichment media 5. Differential media. Just list put techniques name so that i could learn it from basics. Could u tell me what are the microbial techniques? Just list out the techniques name so that i could learn it from basics. Save my name and email in this browser for the next time I comment.
Composition of Nutrient Agar 0. Distilled water Water is essential for the growth of and reproduction of micro-organisms and also provides the medium through which various nutrients can be transported. Preparation of Nutrient Agar 1. Suspend 28 g of nutrient agar powder in 1 litre of distilled water.
Heat this mixture while stirring to fully dissolve all components. Autoclave the dissolved mixture at degrees Celsius for 15 minutes.
Once the nutrient agar has been autoclaved, allow it to cool but not solidify. Replace the lid of each Petri dish and store the plates in a refrigerator. Uses of Nutrients Agar 1. It is frequently used for isolation and purification of cultures. Pictures Four nutrient agar plates growing colonies of common Gram negative bacteria.
MacConkey Agar - uninoculated. Purpose: Contains bile salts and crystal violet which selects for gram-negative enterics, differentiates lactose-fermenters from non-fermenters. Can include sugars other than lactose for further differentiation for example, to differentiate enterohemorrhagic E. Interpretation: Selects for non-fastidious gram-negatives; red colonies indicate fermentation of lactose, white indicates no fermentation of lactose. MacConkey Agar - Escherichia coli Note: Red colonies and red precipitate due to acid production as a result of lactose fermentation.
Colorless colonies, medium is slightly yellow due to the increased pH resulting from bacterial digestion of peptone in the medium. Eosin Methylene Blue Agar - uninoculated. Type: Differential lactose and selective dye inhibition and precipitation at acid pH. Purpose: Differentiates lactose fermenters E. Eosin Methylene Blue Agar - Salmonella enteritidis Note: pink colonies indicative of non-lactose fermentation.
Eosin Methylene Blue Agar - Escherichia coli Note: Green metallic sheen indicative of dye precipitation due to lactose fermentation. Eosin Methylene Blue Agar - Klebsiella pneumoniae Note: Mucoid colonies with dark centers due to capsule production and lactose fermentation respectively.
Hektoen Agar. Hektoen - uninoculated. Purpose: Detects lactose fermentation, H 2 S production, inhibits non-enterics. Interpretation: Lactose fermenters yellow or salmon, non-fermenters colorless; H 2 S production produces black precipitate.
Hektoen - Escherichia coli Note: Orange color indicates acid production as a result of lactose fermentation. Mannitol Salt Agar. Mannitol Salt Agar - uninoculated. Purpose: Selects for Staphylococci, which grow at high salt concentrations; differentiates Staphylococcus aureus from other Staphylococci.
Interpretation: Staphylococcus aureus is yellow ferments mannitol , other staphylococci are white. Mannitol Salt Agar - Staphylococcus epidermidis Note: growth, but no fermentation of mannitol, medium color unchanged. It consists of peptone, beef extract, and agar. This relatively simple formulation provides the nutrients necessary for the replication of a large number of non-fastidious microorganisms.
Final pH 6. Composition of nutrient broth: Nutrient broth contains all these ingredients except agar. Nutrient agar and broth are available from most suppliers of culture media in powdered free-flowing, homogeneous form. Shelf life: Up to 2 years providing there is no change in the appearance of the medium to suggest contamination or deterioration. Prepare from ready to use dehydrated nutrient broth powder.
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