Neonicotinoids

[Gaylord]

I see that neonicotinoids are getting much of the blame for crashing honeybee populations. Originally, they were touted as a safer alternative to organophosphate insecticides.

 

Can anyone help me out as to the molecular mode of action for neonicotinoids and the biological activity and environmental persistence of neonicotinoid metabolic products?

[John Cuthber]

They act in the same way as nicotine.

http://en.wikipedia.org/wiki/Nicotine#Pharmacology

Hence the name.

[Gaylord]

On a related subject, what influences the potency or species specificity of organophosphates. As I understand it, all organophosphates act as non-competitive, irreversible acetylcholinesterase inhibitors. But some work very well on arthopods but have little effect on humans. And, of course, some organophosphates are so lethal to humans that they make particularly ghastly chemical weapons. What distinguishes insecticide organophosphates from military organophosphates? How closely are developers of insecticides supervised by governments? The idea of rogue organic chemists getting product development jobs at agricultural chemical companies is the kind of thing that makes me nervous.

[John Cuthber]

You could write a book about the differences in toxicity for different species- someone has.

http://books.google.co.uk/books/about/Selective_toxicity.html?id=V7gwAAAAIAAJ

 

In the case of the organophosphates there are a number of ways in which they make chemicals that are more toxic to bugs than to people.

One important one is to use thiophosphates rather than phosphates.

The insects metabolise them and convert the thioester to the oxy ester which is much more toxic.

On the other hand, mammals hydrolyse them which pretty much destroys their toxicity.

 

There are a whole bunch of regulations concerning, not just pesticides, but all chemical products on the market.

This one is a particularly good cure for insomnia.

http://eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=oj:l:2006:396:0001:0849:en:pdf

 

There are also regulations that apply just to pesticides.

http://www.legislation.gov.uk/uksi/1986/1510/contents/made

 

What do you think a rogue chemist could actually do if he worked in the product development group?

[Gaylord]

I suppose that a rogue chemist could take what he learned making insecticides and apply that knowledge in his basement garage.

I'm also just interested in toxins in general. Few people realize what a toxic world we live in. I get a kick out of vegetarians when I tell them that every plant on earth is toxic.

Most are not acutely toxic to humans or even mammals. Most are aimed at insect predators. And some of those toxins we actually seek out. Caffeine and nicotine come to mind.

Another under appreciated class of phytotoxins is the phytoestrogens and phytoprogestins. These act as birth control pills that reduce the reproductive activity of the predator.

Neurotoxins are the most interesting though. Acetylcholine esterase inhibitors and acetylcholine mimics especially.

 

 

 

 

http://books.google....id=V7gwAAAAIAAJ

 

In the case of the organophosphates there are a number of ways in which they make chemicals that are more toxic to bugs than to people.

One important one is to use thiophosphates rather than phosphates.

The insects metabolise them and convert the thioester to the oxy ester which is much more toxic.

On the other hand, mammals hydrolyse them which pretty much destroys their toxicity.

 

There are a whole bunch of regulations concerning, not just pesticides, but all chemical products on the market.

This one is a particularly good cure for insomnia.

http://eur-lex.europ...001:0849:en:pdf

 

There are also regulations that apply just to pesticides.

http://www.legislati...0/contents/made

 

What do you think a rogue chemist could actually do if he worked in the product development group?