This fragment can also be labeled and used for dot blot
or in situ hybridization assays. The problem with these 2
techniques is that the viral RNA is very labile and must be
protected during specimen preparation. For in situ
hybridization using fixed tissues, it is important not to
use Davidson's fixative for too long a period or not to use
it at all. This is because it is acidic and will destroy the
RNA. IfDavidson's fixative is used, it should be used only
overnight and be followed by immediate dehydration and
embedding. Alternatively, an RNA-friendly fixative has
been previously reported (Hasson et al., 1997). Briefly this
method uses a formulawhere the acetic acid in Davidson's
fixative is replaced with additional formalin. It employs
shrimp tissues that have had the cuticle removed. After