RE: Hormesis again?

["Bjorn Cedervall" <bcradsafers@HOTMAIL.COM>]

Increased fertility or growth may not necessarily mean "improved health". A 

stress reaction (as I pointed out here on Radsafers about 3 years ago) may 

simply mean - "look - you may die indirectly due to genetic and other types 

of damage - so you have better reproduce quickly and as much as possible so 

that there is an enhanced probability of a few - and in best case mutant 

survivors with an even better chance of survival". (There is a classical 

example found in the RecA system in E. coli)



This could be an example where the stress is positive for the long-tem 

effect of the population but statistically detrimental on the individual 

level.



A practical example of lots of progeny is found among the often small 

Brassicaceae (Angiosperm family - previously named Cruciferae) plants which 

are common on streets in cities. These run a high risk of disappearing due 

to whatever goes on on streets so they invest little in a complicated root 

system. Instead they shoot up quickly, flower and spreads lots of seeds. 

Many individuals are probably lost but the population is healthy. Lepidium 

ruderale (Narrow-leaved Pepperwort) is an example:

http://linnaeus.nrm.se/flora/di/brassica/lepid/lepirud2.jpg

http://linnaeus.nrm.se/flora/di/brassica/lepid/lepirud1.jpg



Similar characteristics can be found for some members of the Asteraceae 

(previously Compositae) and grass family Poaeceae (previously Graminae).



I may mention that these are reflections I made when I spent several years 

(sparetime hobby) in the seventies studying what grew in the two most 

exploited suburbs next to Stockholm - most of it is asphalt, streets, roads 

or otherwise very disturbed land.



>From a genetic aspect there should probably be a "balanced" (related to the 

average stress and danger seen a per generation and extinction 

risk/vulnerability perspective) inflow of mutations into any population.



So we are back to the difference between observation and interpretation. I 

have made a reasonable interpretation above.



Bjorn Cedervall      bcradsafers@hotmail.com

http://www.geocities.com/bjorn_cedervall/



I have deliberately left some of the previous comments which I believe are 

most relevant to my response. It would, however, be nice if some Radsafers 

could do more to clean up their messages from totally unnecessary previous 

content.

------

From: "Jacobus, John (OD/ORS)" <jacobusj@ors.od.nih.gov>

Date: Fri, 8 Feb 2002 09:56:29 -0500



Jim,

Since you asked, here are some thoughts on this new item.



Item: Microwave radiation used

Increased fertility in nematodes

Progeny are 10 larger.



Questions:

1.  What is the mechanism?  Genetic changes? Hormonal?



2.  What are the long term effects?  Early Death?  Are there developmental 

abnormalities that may not be evident at the current investigational levels?



3.  Are the effects reversible?  If you stop irradiating with microwaves, do 

fertility levels and size return to pre-irradiation levels?  Does it drop 

due to affects on the immediate progeny, leading to smaller populations and

size in future generations?



4.  What are the effects of continuous irradiation over several generations? 

Mutations or developmental abnormalities (both good and bad) that increase 

in each future generation?





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