From:Geoff McAuliffe <mcauliff@UMDNJ.EDU>

Bruce Abaloz wrote:

> Dear Histonetters,
> Can anyone give me any suggestions on how to prepare a lacmoid solution for ooctye staining?
> We found it very difficult to get lacmoid crystals, and the batch we finally got our hands on is very old.  I needed to prepare a 1% lacmoid solution and placed 1g of lacmoid crystals in 45% acetic acid and left it on a stirrer/hot plate for 2 hours at a moderate heat.  When I filtered it there was still a large amount of crystal undissolved (about half), yet a reasonable amount of colour in the solution.  The undissolved crystal was more grey in colour than they grey/burgundy of the original crystal.
> Does anyone know if this is an appropriate method of preparation?  I can't believe my solution is a 1% solution if there is undissolved crystal?
> DEPARTMENT of ZOOLOGY              *  PH:    +61 3 83446282
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Dear Bruce:

    The 4th edition of "Staining Proceedures" mentions lacmoid only as a stain for plant material. The proceedures I looked at called for 0.25% lacmoid in 30% ethanol with a few ml of 1% NaHCO3 added. That solution would be alkaline, yours is acidic. The 10th edition of the "Microtomists Vade-Mecum" calls for 5 mg in 10-15 ml of water with the pH adjusted to 8 with ammonia. Again, a stain for plant material. So perhaps your solution is too concentrated and the wrong pH?
    Hope this helps.

Geoff McAuliffe, Ph.D.
Neuroscience and Cell Biology
Robert Wood Johnson Medical School
675 Hoes Lane, Piscataway, NJ 08854
voice: (732)-235-4583; fax: -4029

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