LCR Paper Abstract

Kevin O'Donnell odonnell at sasa.gov.uk
Wed Apr 17 08:53:23 EST 1996


In article <199604171049.LAA25410 at caird.scri.sari.ac.uk>, 
djones at SCRI.SARI.AC.UK (D Jones) says:

>        I'd be really interested to see the preliminary results you
>refer to. Was the comparison done on dormant tubers, or on tubers on
>which dormancy had been broken? Also what were the comparative 
costs of
>the two techniques? In my experience with molecular techniques, even 
when
>labour costs are taken into account, the cost compared to ELISA can be
>prohibitive. Seeing as ultimately the cost of any test is bourne by the
>grower and farmers are notoriously 'careful with there money' this is an
>important consideration. Any one else have any views?
>
David,

You are welcome to see the preliminary results - in fact if you'd like an 
off-print please let me know.  The work was carried out using purified 
virus and viral RNA rather than tuber material, however that will be the 
next stage.  The paper reports a 10-fold increase in sensitivity over 
ELISA. We have since increased that to 100-fold and believe that there is 
further room for improvement.

You are absolutely correct, IMO, to identify cost as the key criterion in 
agricultural diagnostics.  For many purposes it just doesn't make sense at 
the moment to use nucleic-acid based techniques when cheaper ones do 
the job just as well.  

However, post harvest tuber testing in potatoes may be an exception, 
because of the high costs of the existing method. for example, greenhouse 
space for 6-8 weeks is a significant overhead - especially with a high 
throughput of samples.   The grower is also inconvenienced by the long 
wait to discover whether his crop is of a good enough standard to be sold 
as seed or whether it must be sold as ware. For that reason they may be 
willing to pay a slightly higher price for a faster test, if given the choice.

Once the method is optimised and a direct comparison made with ELISA 
on  tests on dormant tubers, then we will be able to compare costs.  All I 
can say at the moment is that I expect the costs to be in the same 
'ballpark'. The capacity of the LCR method to dispence with the costs 
associated with electrophoresis willl be a help here.

Kevin

Dr Kevin O'Donnell
Diagnostics and Molecular Biology
SASA
Edinburgh



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