Glossary entry (derived from question below)
English term or phrase:
overlay agar
English answer:
plating (out) agar, top agar; soft, low setting temperature agar
Added to glossary by
Jörgen Slet
Nov 5, 2003 09:12
21 yrs ago
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English term
Estonia
19 years of biomedical translation
Native in: Estonian 
Works in: English to Estonian, Estonian to English
overlay agar
English
Science
molecular biology
the direct incorporation method in which bacteria and test agent are mixed in overlay agar and poured over the surface of a selective agar plate.
Responses
| 5 +2 | overlay or plating agar |
achisholm
|
Responses
+2
4 mins
Selected
overlay or plating agar
The bacteria and other agents (viruses/phages etc.) are mixed with warm, soft, low setting temperature agar and poured onto preset hard agar plates.
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Note added at 2003-11-05 09:26:43 (GMT)
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The selctive agar plate is set agar with the selective materials already incorporated (usually drugs or antibiotics). The bacteria and test agent are then mixed, preincubated (in order to allow them to be absorbed by the bacteria) and then added to a few ml of melted overlay or plating agar. This is a relatively low melting point agar, and is usually more dilute than the selective agar. This is then poured over the selective plate and allowed to set. The bacteria can then grow in this overlay agar, the less rigid consistency allows relatively free diffusion of gasses and nutrients etc. The idea is that over time, a \"lawn\" of bacteria will form, which may be more or less dense with respect to bacterial growth depending on the effect of the test agent. If the test agent is a lytic phage or virus, this will cause lysis of the bacteria resulting in a clear patch, easily seen against the lawn of \"healthy\" bacteria. This is ised to \"titre\" a phage/virus stock and is also how recombinant cDNA libraries are screened.
Sinonyms are:-
overlay agar
plating (out) agar
top agar etc.
HTH
Sandy
see
http://fruitfly4.aecom.yu.edu/labmanual/61.html
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Note added at 2003-11-05 09:27:43 (GMT)
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sorry - sinonyms for sinonym are synonym!!!
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Note added at 2003-11-05 09:26:43 (GMT)
--------------------------------------------------
The selctive agar plate is set agar with the selective materials already incorporated (usually drugs or antibiotics). The bacteria and test agent are then mixed, preincubated (in order to allow them to be absorbed by the bacteria) and then added to a few ml of melted overlay or plating agar. This is a relatively low melting point agar, and is usually more dilute than the selective agar. This is then poured over the selective plate and allowed to set. The bacteria can then grow in this overlay agar, the less rigid consistency allows relatively free diffusion of gasses and nutrients etc. The idea is that over time, a \"lawn\" of bacteria will form, which may be more or less dense with respect to bacterial growth depending on the effect of the test agent. If the test agent is a lytic phage or virus, this will cause lysis of the bacteria resulting in a clear patch, easily seen against the lawn of \"healthy\" bacteria. This is ised to \"titre\" a phage/virus stock and is also how recombinant cDNA libraries are screened.
Sinonyms are:-
overlay agar
plating (out) agar
top agar etc.
HTH
Sandy
see
http://fruitfly4.aecom.yu.edu/labmanual/61.html
--------------------------------------------------
Note added at 2003-11-05 09:27:43 (GMT)
--------------------------------------------------
sorry - sinonyms for sinonym are synonym!!!
4 KudoZ points awarded for this answer.
Comment: "Thanks everybody"
Discussion
The test is Escherichia coli reverse mutation assay for mutagenicity of chemical substances.
Now when you say "agar plate" does the "plate" refer to agar formation or the test vessel ?