Again, Re: sectioning insects

From:Gayle Callis

Hmmm a tape tranfer might help, Sterchi did this with large bone sections,
is in Journal of Histotechnology some years back, if you are interested
will dig out reference. I loved Barry's reply! 

Gayle Callis 

At 03:04 PM 2/27/02 -0600, you wrote:
>Most of the experience I had sectioning insects was looking at
>dragonflies and dragonfly larvae almost 40 years ago but I did spend a
>lot of time researching of methods to produce sections of the head
>The most effective method I found was to concentrate on the processing
>itself. I mixed melt equal parts of chloral hydrate and phenol together
>by gentle warming and used as the chitin softening agent (I cannot claim
>credit for this and chloral hydrate is probably difficult to get chloral
>hydrate unless in business of shanghaiing sailors!)). This solution was
>used after dehydration and specimens were left for up to a week in this
>solution. Usually a day was adequate but did not hurt leaving much
>longer. Then chloroform as an intermediary agent.
>Most of the other methods that I tried such as softening with hydroxides
>did not seem to be effective.
>I think that effectiveness may depend largely on the insects and probably
>will not work with thick shelled coleoptera.
>Some of the older methods suggested snipping off a piece of the outer
>chitin to allow penetration of agents through the rest of the body of the
>An alternate is to use double embedding with celloidin-wax. Found this to
>work but not as well as first method.
>Yet another method was to use isopropyl alcohol dehydration in place of
>ethanol dehydration to minimize hardening. Worked reasonably well for
>larvae but was not as effective for  adult dragonflies.
>If the insects have already been embedded I would recommend soaking the
>block in water or using Mollifex.
>If the chitin tends to separate you might try to use the technique of
>wiping a block of 45 degree wax over the surface before cutting each
>section. Failing this (and probably by this time after several
>Guinesses)- try  painting a thin layer of celloidin on the surface, allow
>to dry and then cut the sections. This is time consuming but sometimes
>Effects on DNA - no idea?
>Tom Clarke wrote:
>> Does anyone have any experience sectioning paraffin embedded insects?
>> Are there any methods that can be used to soften the chitin without
>> significantly damaging the other tissues (in particular, the DNA)?
>>   -Tom Clarke-
>>    Division of Biology
>>    Kansas State University

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