Bacteria On Agar Plates

10 plates necessitates a 5g lb agar powder mixed with 125ml of water.

Bacteria on agar plates. Different species of bacteria can produce very different colonies. Identifying viruses on agar plates is a different story and rely on methods such as differences in viral plaque phenotype selective media contain substances that will inhibit growth of organisms while allowing for only a specific type of organism to grow. The agar serves as food for the bacteria. On solid media a single microbe will grow and divide to produce a colony a spot of identical descendants.

Blood agar plates baps contain mammalian blood usually sheep or horse typically at a concentration of 5 10. Agar is the perfect substance for biological experiments as it holds up to bacteria and doesn t disintegrate easily. The addition of agar to lb results in the formation of a gel that bacteria can grow on as they are unable to digest the agar but can gather nutrition from the lb within. Each distinct circular colony should represent an individual bacterial cell or group that has divided repeatedly.

Nine obviously different colonies are numbered. A common ratio to remember when making your lb agar mix is 40g to 1l of water ratio this ratio will make about 80 plates. β hemolytic activity will show lysis and complete digestion of red blood cell contents surrounding a colony. There are a number of ways to make an agar plate or agar filled petri dish.

Agar plates are the standard solid support material for growing microorganisms. Microbial growth media contains nutrients and an energy source to fuel the microbes as they grow and agar to keep the media in a semi solid gel like state. Being kept in one place the resulting cells have accumulated to form a visible patch. In the above picture of a mixed culture an agar plate that has been exposed to the air and many different colony morphologies can be identified.

The addition of an antibiotic to this gel allows for the selection of only those bacteria with resistance to that antibiotic usually conferred by a plasmid carrying the. Examples include streptococcus haemolyticus. Put the nutrient agar plates into a zipper lock bag and keep the plates upside down and place them in a. Growing bacteria in a nutrient agar plate is a great way to see bacteria because each one becomes a colony of thousands of bacteria.

Don t forgot to have a control in your experiment. To start we will talk about a bacterial base in which we use lb agar. Some colony types recur in various areas of the plate note 3 and 4. Baps are enriched differential media used to isolate fastidious organisms and detect hemolytic activity.

Bacteria are so tiny they cant be seen with the naked eye and often millions of bacteria are condensed in a small spot. Label the agar plates with a marker pen sharpie on the bottom of the agar plate the agar side not the lid side. Place the lid back and put agar plate upside down. Agar is the gelatinous substance that sits inside the petri dishes used by scientists and students alike.