Biomedical Laboratory Science

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Showing posts with label Bacteriology. Show all posts
Showing posts with label Bacteriology. Show all posts

Thursday, April 21, 2016

MacConkey Agar (MAC): Composition, preparation, application and colony characteristics

MacConkey agar was developed in 20th century by Alfred Theodore MacConkey. It was the first formulated solid differential media. MacConkey Agar is a selective and differential culture media commonly used for the isolation of enteric Gram-negative bacteria. It is based on the bile salt-neutral red-lactose agar of MacConkey. Crystal violet and bile salts in incorporated in MacConkey Agar to prevent the growth of gram-positive bacteria and fastidious gram-negative bacteria, such as Neisseria and Pasteurella. Gram-negative enteric bacteria can tolerate to bile salt because of their bile-resistant outer membrane.

MacConkey Agar is selective for Gram negative organisms, and helps to differentiate lactose fermenting gram negative rods from Non lactose fermenting gram negative rods. It is primarily used for detection and isolation of members of family enterobacteriaceae and Pseudomonas spp.

Composition of MacConeky Agar:
Enzymatic Digest of Gelatin, Casein and Animal tissue: provides nitrogen, vitamins, minerals and amino acids essential for growth.


LF and NLF colonies in MacConkey Agar
Source: microbeonline

Tuesday, March 29, 2016

Tweaking Gut Bacteria Could help Prevent Brain Strokes

Recent research has shown how fundamentally important the bacteria in our gut are to the rest of our mental and physical health, affecting everything from our appetite to our state of mind.

Now a new study suggests that our gut bacteria could even play a role in protecting us from brain damage, with an experiment involving mice showing that certain types of stomach microbes can actually help reduce the severity of strokes.

"Our experiment shows a new relationship between the brain and the intestine,"said neuroscientist Josef Anrather from the Feil Family Brain and Mind Research Institute at Cornell University. "The intestinal microbiota shape stroke outcome, which will have an impact [on] how the medical community views stroke and defines stroke risk."

Anrather and his colleagues analyed two groups of mice – one received a combination of antibiotics that tweaked their gut microbiota, and the other acted as a control group, with no alterations made to their gut microbiota over the course of the experiment.

Read more:
Tweaking Gut Bacteria Could help Prevent Brain Strokes


Source: anufrench
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