BBC News

[steve_e]

Oops. Only read this thread, sorry. I was, as you say, not keeping up!

 

[frenchbees]

I heard this on radio 4 farming today this morning.
The explanation was that the double stranded RNA mimics a virus attacking the varroa mite. The varroa mite attacks the "virus" but as it is also coded for a varroa gene the varroa effectively destroys itself.
So far so good, but the delivery method is to add the RNA in liquid form to the sugar syrup which the beekeeper is feeding. The bees then use this in the brood food and the RNA soaks into the mite in the cell.
Here I am unsure, would bees take syrup at this time of year as presumably it would need to be fed over the summer?
Suggested the treatment would be available in 5 years.

 

[Dishmop]

Suggested the treatment would be available in 5 years.

so its probably just still theory then...

 

[drstitson]

"Here I am unsure, would bees take syrup at this time of year as presumably it would need to be fed over the summer?"

if targetting varroa in brood then you'd feed when brood present eg spring build up feed.

"double stranded RNA mimics a virus attacking the varroa mite. The varroa mite attacks the "virus" but as it is also coded for a varroa gene the varroa effectively destroys itself."

sort of - all eukaryotic organisms have a conserved system to destroy viruses based on their nucleic acid structure (double stranded RNA). The technique takes advantage of this to deliver antisense RNA (complimentary to the RNA produced when a gene is "read" to ultimately make proteins for the cell) which pairs up with the RNA made by the cell, leading to its destruction.
single stranded RNA is very unstable and so to get reliable delivery you need to use double stranded in the first place. so the "virus disposal system" is in fact used twice - once to "prime" the weapon once in the cell and then to "destroy" the target gene product and hence hopefully kill the mite.

 

[Rosti]

so its probably just still theory then...

No Dishmop, as I read it, it is beyond that, read the supplimentary text, it has been trialed successfully, the issue appears to be the development of a delivery system and required effective dosing concentrations - and of course the human validation stages. The theory of this group/type of treatment is very well established and understood, granted not in this area though

Don't look for more info on the BBKA news home page though, it's not there yet ..... but if you'd like info on a Saga adopt a hive application form they can help you

 

[drstitson]

"No Dishmop, as I read it, it is beyond that, read the supplimentary text, it has been trialed successfully, the issue appears to be the development of a delivery system and required effective dosing concentrations - and of course the human validation stages. The theory of this group/type of treatment is very well established and understood, granted not in this area though"

yes they have shown that RNAi delivered via immersion achieves similar knockdown of GST target gene (a ubiquitous enzyme - which is why they were able to get sequence data ahead of varroa genome project analysis - they fished for sequence matches using deer tick GST sequence - see quote below) as direct injection of mites.

all well and good but now they need, as stated, to determine amounts needed to deliver to a hive AND more importantly, to await genome sequence to allow the identification of targets (although as the team work on other arthropods they may well have ideas as to potential target genes already).

"A V. destructor database from an ongoing pyrosequencing
project (Dr. Jay Evans, pers. comm.) was mined for
putative V. destructor GST sequences by BLASTx analysis
using GST sequences from the deer tick, Ixodes scapularis."

 

[newportbuzz]

i dont think this can work unless this treatment stays in the bee. As the varroa mite enters the cell just as it is about to be capped, Ie very little brood food in there then. so whats the varoa mite gunna have a bath in to make it sick?????????????. if however it remains viable inside the bee and the varroa eats from a bee that is carrying the treatment then it would work???yes/no???

 

[Polyanwood]

The idea is that it needs to be incorporated into the brood food, and because they put some of that in each cell with every larva (including the ones where varroa are already enconsed) then the RNAi will get into every bee. They also mentioned feeding the bees with honey that had the RNAi in it.

 

[drstitson]

i would have thought that transmission through feed won't work - the dsRNA is unlikely to survive digestion by the larvae let alone make it into the haemolymph.

Better to aim use a charged aerosol vehicle to spray all your bees and combs etc.

however can't see it being any better and certainly not cheaper than our current methods of varroa control.