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How would you recognize a coliform on desoxycholate and EMB agar?
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What selective growth media is best suited for isolation of coliform bacteria?
MacConkey agar is commonly used for isolation of coliform bacteria as it selectively allows for the growth of Gram-negative bacteria, including coliforms, while inhibiting the growth of Gram-positive bacteria. Additionally, Eosin Methylene Blue (EMB) agar can also be used for the isolation of coliform bacteria as it helps differentiate between lactose-fermenting and non-lactose fermenting Gram-negative bacteria.
How many teaspoons is 7 g agar agar powder?
Approximately 2 teaspoons of agar agar powder is equivalent to 7 grams.
From which organism agar agar is extracted?
Agar agar is extracted from red algae, specifically from the cell walls of species such as Gelidium, Gracilaria, and Pterocladia.
Is there a microorganism that degrades Agar agar?
Yes, some marine bacteria and fungi have been identified to possess the capability to degrade agar agar. These microorganisms secrete enzymes such as agarases that breakdown agar into simpler sugars, which they can then use as a source of energy.
Which group of algae produce agar agar?
Agar comes from Red Algae (primarily the Gracilaria genus).It mainly is produed from the red algae Gracilaria lichenoides.This algae is harvested along the western coast of the United States and in parts of Asia. To extract the agar the Algae is boiled, cooled, purified and then dried. The agar is then make into blocks, flakes, or granules.("Agar agar" is usually abbreviated as "agar".)
What selective growth media is best suited for isolation of coliform bacteria?
MacConkey agar is commonly used for isolation of coliform bacteria as it selectively allows for the growth of Gram-negative bacteria, including coliforms, while inhibiting the growth of Gram-positive bacteria. Additionally, Eosin Methylene Blue (EMB) agar can also be used for the isolation of coliform bacteria as it helps differentiate between lactose-fermenting and non-lactose fermenting Gram-negative bacteria.
What ingredients in EMB agar contain carbon and nitrogen?
The peptones in EMB agar provide nitrogen for bacterial growth, while the lactose is a source of carbon. These ingredients support the growth of certain coliform bacteria, which ferment lactose to produce characteristic color changes on the agar.
What conclusions may be drawn if no growth appeared on MacConkey agar and emb agar after inoculation of the media and an incubation period?
If no growth appeared on MacConkey agar, it may indicate that the organism does not ferment lactose or it is not a gram-negative bacterium. If no growth appeared on EMB agar, it may suggest that the organism does not ferment lactose or it is not a coliform bacterium. Further testing would be needed to identify the organism.
Why coliform show pink color colony in violet red bile agar?
Coliform bacteria, such as E. coli, produce acid during fermentation which causes the pH indicator in violet red bile agar to turn pink. This characteristic pink coloration of coliform colonies helps in their differentiation from other bacteria present in the sample.
What would be possible consequence of replacing the lactose with glucose on the MacConkey Agar?
Replacing lactose with glucose on MacConkey Agar would inhibit the differentiation of lactose-fermenting vs. non-fermenting bacteria. This would make it difficult to identify lactose-fermenting organisms, as they would not produce the characteristic pink/red color on the agar plate. Additionally, it may lead to misinterpretation of results when testing for lactose fermentation in microbiology.
How do you recognize bacteria on agar plate and not confusing bacteria with eukaryotes like yeast or fungi?
Use selective media agar plates. Different types of agar will let bacteria grow and inhibit fungal growth, or vice versa.
Why can't e coli grow on ms agar?
Because this medium is differentially selected to isolate streptococci (E.coli is bacillus). Also because E. coli produces coliform which rarely grows on this medium.
Why do the membrane filtration and the colilert IDEXX technique for measuring fecal coliforms in waste water produce discrepant results?
The membrane filter / agar plates produce colonies from bacteria that can grow on the agar you are using (not all fecal coliforms can). The Colilert will turn color if the bacteria have the enzyme to metabolize substrates in the Colilert (not all do). If all fecal coliform bacteria could grow on the agar and all fecal Coliforms had the right enzymes you'd get the same numbers.
What does it mean to inoculate an agar plate?
Inoculating an agar plate refers to transferring microorganisms onto the surface of the agar using a sterile inoculating loop. This allows the microorganisms to grow and form visible colonies that can be studied or identified.
Agar agar grain found in Germany?
Agar, or agar-agar, is not a grain, but rather an extract of seaweed. Agar translates to German as Agar-Agar Try whole- or health-food stores
If an organism can grow on both a nutrient agar and a MacConkey Agar on which would you expect it to grow better?
You would expect the organism to grow better on nutrient agar because it is a general-purpose medium that supports the growth of a wide range of organisms. MacConkey agar, on the other hand, contains inhibitors that selectively inhibit the growth of Gram-negative bacteria, so the organism may not grow as well on this medium.
What jelly is made from seaweed and used in glue making?
Agar-agar
