Agar Plates
Agar Plates
I've been making nutrient agar plates for years with very good growth of bacteria of all sorts using agar that was in my store.
However, I purchased new nutrient agar 6 months ago and now the vast majority of the plates hardly grow anything. My technique hasn't changed. Is anyone else having this problem? The bottles I bought aren't cheap but if it doesn't grow anything it's useless.
However, I purchased new nutrient agar 6 months ago and now the vast majority of the plates hardly grow anything. My technique hasn't changed. Is anyone else having this problem? The bottles I bought aren't cheap but if it doesn't grow anything it's useless.
- Labbie
- Posts: 3243
- Joined: 28 Nov 2006, 10:00
- Job Title: Retired
- Suburb: At Home
- State/Location: NSW
Re: Agar Plates
I have had trouble with Agar 1000 gel powed, but never the Nutrient agar, where did you purchase it from?
Regards Labbie
Lab Manager/Lab Tech, mind reading etc etc
Now retired
Lab Manager/Lab Tech, mind reading etc etc
Now retired
Re: Agar Plates
Serrata
- Labbie
- Posts: 3243
- Joined: 28 Nov 2006, 10:00
- Job Title: Retired
- Suburb: At Home
- State/Location: NSW
Re: Agar Plates
Ring them, the supplier may do a refund.
Regards Labbie
Lab Manager/Lab Tech, mind reading etc etc
Now retired
Lab Manager/Lab Tech, mind reading etc etc
Now retired
-
- Posts: 829
- Joined: 15 Dec 2015, 10:49
- Job Title: Lab Technician
- School: FCAC
- State/Location: QLD
Re: Agar Plates
I read that you should store Agar plates upside down after making them .
I fail to understand the logic in this .
Can anyone explain why ...I must be missing something .
I fail to understand the logic in this .
Can anyone explain why ...I must be missing something .
- Labbie
- Posts: 3243
- Joined: 28 Nov 2006, 10:00
- Job Title: Retired
- Suburb: At Home
- State/Location: NSW
Re: Agar Plates
so the lids stay dry, no condensation.
Regards Labbie
Lab Manager/Lab Tech, mind reading etc etc
Now retired
Lab Manager/Lab Tech, mind reading etc etc
Now retired
-
- Posts: 38
- Joined: 09 Dec 2016, 13:11
- Job Title: lab assistant
- School: SJBC
- Suburb: Engadine
- State/Location: NSW
Re: Agar Plates
Try southern biological, never had an issue with their agar (plain agar powder). Recipe I use is 10g bonox (beef extract), 10g peptone, 5g NaCl, 15g agar powder, 1L distilled water. Never had any issues with the supplier or this recipe.
Agar plates should always be stored and incubated upside down to prevent growth from condensation
Agar plates should always be stored and incubated upside down to prevent growth from condensation
-
- Posts: 1496
- Joined: 12 Mar 2013, 08:10
- Job Title: Labbie
- School: Wollondilly Anglican College
- Suburb: Tahmoor
- State/Location: NSW
Re: Agar Plates
They're stored upside down to prevent condensation settling on the agar.
-
- Posts: 829
- Joined: 15 Dec 2015, 10:49
- Job Title: Lab Technician
- School: FCAC
- State/Location: QLD
Re: Agar Plates
Thanks Labbie and shell .
when I make them and they are setting , condensation forms on the lids . I tip them upside down and store in fridge , next day there are obvious pools on some of the agar plates but not all and there is some condensation on the inverted lids . I find it a bit hit and miss still .
So is the theory that the condensation can escape up the gap between the lid and base ? I was concerned thinking that "stuff" could fall back down into them
when I make them and they are setting , condensation forms on the lids . I tip them upside down and store in fridge , next day there are obvious pools on some of the agar plates but not all and there is some condensation on the inverted lids . I find it a bit hit and miss still .
So is the theory that the condensation can escape up the gap between the lid and base ? I was concerned thinking that "stuff" could fall back down into them
-
- Posts: 38
- Joined: 09 Dec 2016, 13:11
- Job Title: lab assistant
- School: SJBC
- Suburb: Engadine
- State/Location: NSW
Re: Agar Plates
Once the agar has set I turn them upside down and place them back into the bag the original agar plates came in and seal the bag with some tape before putting into fridge. I only seem to get condensation within the bag and not the plates. Hope this helps
- Lyn
- Posts: 706
- Joined: 16 May 2006, 10:00
- Job Title: Lab Assistant (Technician)
- School: St. John's Catholic College
- Suburb: Darwin
- State/Location: NT
Re: Agar Plates
Same here. Once plates are set I pop them into ziplock sandwich bags (about five plates to a bag) and store them upside down in the fridge.
Re: Agar Plates
What a great idea, Shell1 and Lyn - can't wait to try it, makes the plates so much easier to handle, too!
Re: Agar Plates
Kanamycin sulfate for Kanamycin agar plates. Does any-one know how long Kanamycin Sulfate solution (34mg/ml) can be stored and whether it should be stored at 4C or -20C?
- Labbie
- Posts: 3243
- Joined: 28 Nov 2006, 10:00
- Job Title: Retired
- Suburb: At Home
- State/Location: NSW
Re: Agar Plates
Kanamycin monosulfate
from Streptomyces kanamyceticus
Product Number K0879
Storage Temperature 2-8 °C
Product Description
Molecular Formula: C18H36N4O11 · H2SO4
Molecular Weight: 582.6
CAS Number: 25389-94-0
This product is g-irradiated and is recommended for
use in molecular biology applications at 10-50 mg/ml.
Kanamycin sulfate is an antimicrobial agent effective
against Gram-negative and Gram-positive bacteria
and mycoplasma. It binds to the 70S ribosomal
subunit, inhibits translocation, and elicits miscoding.
Cross-resistance occurs between kanamycin and
neomycin, framycetin, and paromomycin, and partial
cross-resistance has been reported between
kanamycin and streptomycin.1
Aminoglycosidemodifying
enzymes (acetyltransferase,
phosphotransferase, nucleotidyltransferase) alter the
antibiotic, preventing its interaction with ribosomes.
Kanamycin sulfate can be added into agar (agar
plate), and the plate should be then be sealed to
prevent any evaporation of moisture from the agar.
The sealed plate can be stored at 2-8 °C for about one
month. If the plate is not sealed to prevent
evaporation of moisture, the kanamycin can degrade.
Precautions and Disclaimer
For Laboratory Use Only. Not for drug, household or
other uses.
Preparation Instructions
Prepare stock solutions directly in the vial with sterile
water (10 mg/ml).
Kanamycin sulfate is soluble in water (50 mg/ml),
yielding a clear solution. Kanamycin sulfate is
practically insoluble in alcohol, acetone, chloroform,
ether, and ethyl acetate. A 1% solution in water has a
pH of 6.5 to 8.5. This is in contrast to the pH of 5.5 to
7.5 for a 1% solution in water of kanamycin acid
sulfate.1
Storage/Stability
Sterile solutions can be prepared by sterile filtration
through a 0.2 mm filter. Solutions are stable at 37 °C
for approximately 5 days. Aqueous stock solutions
can be stored at 2-8 °C for long term storage.
References
1. Martindale The Extra Pharmacopoeia, 31st ed.,
Reynolds, J. E. F., ed., Royal Pharmaceutical
Society (London, England: 1996), p. 244.
JSX/ARO/HLD/RXR 5/06
from Streptomyces kanamyceticus
Product Number K0879
Storage Temperature 2-8 °C
Product Description
Molecular Formula: C18H36N4O11 · H2SO4
Molecular Weight: 582.6
CAS Number: 25389-94-0
This product is g-irradiated and is recommended for
use in molecular biology applications at 10-50 mg/ml.
Kanamycin sulfate is an antimicrobial agent effective
against Gram-negative and Gram-positive bacteria
and mycoplasma. It binds to the 70S ribosomal
subunit, inhibits translocation, and elicits miscoding.
Cross-resistance occurs between kanamycin and
neomycin, framycetin, and paromomycin, and partial
cross-resistance has been reported between
kanamycin and streptomycin.1
Aminoglycosidemodifying
enzymes (acetyltransferase,
phosphotransferase, nucleotidyltransferase) alter the
antibiotic, preventing its interaction with ribosomes.
Kanamycin sulfate can be added into agar (agar
plate), and the plate should be then be sealed to
prevent any evaporation of moisture from the agar.
The sealed plate can be stored at 2-8 °C for about one
month. If the plate is not sealed to prevent
evaporation of moisture, the kanamycin can degrade.
Precautions and Disclaimer
For Laboratory Use Only. Not for drug, household or
other uses.
Preparation Instructions
Prepare stock solutions directly in the vial with sterile
water (10 mg/ml).
Kanamycin sulfate is soluble in water (50 mg/ml),
yielding a clear solution. Kanamycin sulfate is
practically insoluble in alcohol, acetone, chloroform,
ether, and ethyl acetate. A 1% solution in water has a
pH of 6.5 to 8.5. This is in contrast to the pH of 5.5 to
7.5 for a 1% solution in water of kanamycin acid
sulfate.1
Storage/Stability
Sterile solutions can be prepared by sterile filtration
through a 0.2 mm filter. Solutions are stable at 37 °C
for approximately 5 days. Aqueous stock solutions
can be stored at 2-8 °C for long term storage.
References
1. Martindale The Extra Pharmacopoeia, 31st ed.,
Reynolds, J. E. F., ed., Royal Pharmaceutical
Society (London, England: 1996), p. 244.
JSX/ARO/HLD/RXR 5/06
Regards Labbie
Lab Manager/Lab Tech, mind reading etc etc
Now retired
Lab Manager/Lab Tech, mind reading etc etc
Now retired
Re: Agar Plates
Thanks Labbie for the information on Kanamycin. DavidM
Re: Agar Plates
Shell1 I was interested in the Agar you recommended as it is much cheaper than what we buy from Sigma. Do you mind telling me what you grow on your agar plates. It may be suitable for us and save us a lot of money.
-
- Posts: 513
- Joined: 15 Aug 2011, 10:48
- Job Title: Lab Tech
- School: NDSC
- Suburb: west gippsland
- State/Location: VIC
setting agar-agar
How much agar-agar per 100ml does it take to set it. I have a prac for 1.5% agar-agar and I don't think it will be strong enough.
-
- Posts: 1496
- Joined: 12 Mar 2013, 08:10
- Job Title: Labbie
- School: Wollondilly Anglican College
- Suburb: Tahmoor
- State/Location: NSW
Re: Agar Plates
Off the top of my head, I think it's about 15g per litre of water, so not sure what you'll end up with only 1.5%.
And David, going back to your post from October (which I had missed), the recipe Shell has given you will make something similar to nutrient agar, so broad use. Without the agar, it also makes a great nutrient broth. Yes, it is cheaper, but is a bit more time consuming, so you need to weigh up your material costs against the time it will take to make. When I was making a lot of plates, and had the time, I would use this recipe for the junior classes, and save the purchased nutrient agar for the seniors - although they both worked pretty well.
And David, going back to your post from October (which I had missed), the recipe Shell has given you will make something similar to nutrient agar, so broad use. Without the agar, it also makes a great nutrient broth. Yes, it is cheaper, but is a bit more time consuming, so you need to weigh up your material costs against the time it will take to make. When I was making a lot of plates, and had the time, I would use this recipe for the junior classes, and save the purchased nutrient agar for the seniors - although they both worked pretty well.
-
- Posts: 1496
- Joined: 12 Mar 2013, 08:10
- Job Title: Labbie
- School: Wollondilly Anglican College
- Suburb: Tahmoor
- State/Location: NSW
Re: Agar Plates
Oh, so wrong - 28g per litre is the amount for the nutrient agar I have.
- Labbie
- Posts: 3243
- Joined: 28 Nov 2006, 10:00
- Job Title: Retired
- Suburb: At Home
- State/Location: NSW
Re: Agar Plates
I have bumped this to the top, as there are some great reads, regarding making agar for us all
Regards Labbie
Lab Manager/Lab Tech, mind reading etc etc
Now retired
Lab Manager/Lab Tech, mind reading etc etc
Now retired