[Arabidopsis] brands of agar

Grant Cramer via arab-gen%40net.bio.net (by cramer from unr.edu)
Wed Feb 13 14:15:32 EST 2008


Sorry for the confusion. I miswrote. I meant Phytagel not PhytoAgar.  
That was a brain short circuit!

Grant R. Cramer
Professor
Department of Biochemistry and Molecular Biology, MS 200
University of Nevada, Reno
Reno, NV 89557
(775) 784-4204
cramer from unr.edu
http://www.ag.unr.edu/cramer/



On Feb 13, 2008, at 6:29 AM, Tobias Baskin wrote:

> Greetings,
>         In replies to this thread, Grant Cramer mentions  
> "PhytoAgar" and Brian Forde mentions "PhytagelTM" which I think is  
> the same phytagel we used awhile back too. But is PhytoAgar the  
> same stuff as Phytagel? or are they different? Do you know?
>
>         Thanks,
>                 Tobias
>
> At 4:40 PM -0800 2/12/08, Grant Cramer wrote:
>> I have found very negative effects on root growth using BactoAgar  
>> both from batches in the United States and Australia. I have NEVER  
>> had a problem with PhytoAgar on root growth in root length assays  
>> up to a week. After that they are in the dish for too long and  
>> will suffer. One can supplement with sucrose in a standard quarter  
>> strength Hoaglands solution without problem. I agree you should  
>> not use MS medium or you will suffer from osmotic stress and  
>> perhaps other things that are out of balance for roots. The roots  
>> will grow without the sucrose but slower. It depends on your  
>> experiment, but those shaded cotyledons in a plastic petri dish  
>> can only do so much in the dark or dim light. I always grow them  
>> in the dark, as light inhibits root growth.
>> Grant R. Cramer
>> Professor
>> Department of Biochemistry and Molecular Biology, MS 200
>> University of Nevada, Reno
>> Reno, NV 89557
>> (775) 784-4204
>> cramer from unr.edu
>> http://www.ag.unr.edu/cramer/
>>
>>
>>
>> On Feb 11, 2008, at 6:33 AM, Tobias Baskin wrote:
>>
>>> Dear Tanya,
>>>         Some years ago, we investigated a variety of different  
>>> agars (some of which you mention). We found reproducible  
>>> differences in root elongation rate but perhaps on the order of  
>>> 10 to 20 %. Clearly the roots liked some agar better than others.  
>>> We also found a little bit later when using phytagel that root  
>>> elongation rate depended on the temperature the molten mix was  
>>> held at before pouring, or might have simply been quite  
>>> irreproducible. But again I am talking about differences on the  
>>> order of 20%. Big enough to readily measure but not monstrous. On  
>>> no agar did we see the kind of developmental change you are  
>>> mentioning. On some conditions I have seen (and read) that  
>>> severely salt stressed or water deficit stressed roots will swell  
>>> so I'd guess what you are describing goes way beyond what can be  
>>> expected from different brands/formulations of agar.
>>>
>>>         Hope this helps,
>>>                         Tobias
>>>
>>> At 3:10 PM -0600 2/9/08, Falbel, Tanya G. wrote:
>>>> Colleagues:
>>>>
>>>> Over the years, I've used several brands of agar for growing  
>>>> Arabidopsis seedlings on MS medium,
>>>> from Gibco, Sigma, and others.  I've heard that some groups use  
>>>> Noble agar,
>>>> others, bacto-agar, others in the past have washed their own  
>>>> agar, used phytagel or other
>>>> gelling agents.   I have two questions:
>>>>
>>>> 1) What brands of agar are most commonly in use now by groups?   
>>>> I've found something similar
>>>> to Gibco's Phytagar that is now available through Caisson labs.  
>>>> Other groups seem to like Sigma's
>>>> A1296.  But besides those, what do most groups use?  I'm  
>>>> especially interested in the opinion of
>>>> groups that measure root length or root branching -  growing  
>>>> roots vertically on plates
>>>> for more than just a couple of days. (as opposed to just  
>>>> antibiotic selection)
>>>>
>>>> 2) Does anyone know what inhibitors are washed away? Are  
>>>> micronutrient ions or other toxic
>>>> compounds bound to the crude agar?  Has anyone looked into this?  
>>>> This may have been a question
>>>> that came up among researchers 10 years ago, but I couldn't find  
>>>> any record in the archives.
>>>>
>>>> Here's why I'm asking. I made up a batch of medium with a brand  
>>>> of 'purified agar for microbial use',
>>>> and got a very strong inhibition of root meristems.  Seed  
>>>> germination was good, but roots failed to elongate
>>>> any further after about 4 days of growth. The root meristems  
>>>> became a swollen mess, reminiscent of what
>>>> happens in weak gnom alleles. I'm trying to decide if this is  
>>>> something worth looking into.
>>>>
>>>> I know that for regeneration of plants in tissue culture, folks  
>>>> are very fussy about particular brands of agar.
>>>>
>>>> Please let me know what brands you have used with success or  
>>>> failure.
>>>> I'd be especially interested in other similar experiences -  
>>>> where a  brand
>>>> wreaked havoc on root meristems.
>>>>
>>>> Thanks
>>>>
>>>> Tanya Falbel
>>>> Department of Biology
>>>> 105 Garfield Avenue
>>>> University of Wisconsin-Eau Claire
>>>> Eau Claire, WI 54702-4004,  USA
>>>>
>>>> Tel: 715-836-5087
>>>> Fax: 715-836-5089
>>>>
>>>>
>>>> _______________________________________________
>>>> Arab-gen mailing list
>>>> Arab-gen from net.bio.net
>>>> http://www.bio.net/biomail/listinfo/arab-gen
>>>
>>>
>>> --
>>>       _      ____          __   ____        /  \   /          /  
>>> \    /   \ \        Tobias I. Baskin
>>>     /   /  /          /   \   \      \         Biology Department
>>>    /_ /   __      /__ \   \       \__    611 N. Pleasant St.
>>>   /      /          /       \   \       \        University of  
>>> Massachusetts
>>>  /      /          /         \   \       \          Amherst, MA,  
>>> 01003
>>> /      / ___   /           \   \__/  \ ____
>>> http://www.bio.umass.edu/biology/baskin/
>>> Voice: 413 - 545 - 1533 Fax: 413 - 545 - 3243
>>>
>>> _______________________________________________
>>> Arab-gen mailing list
>>> Arab-gen from net.bio.net
>>> http://www.bio.net/biomail/listinfo/arab-gen
>
>
>



More information about the Arab-gen mailing list