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Re: [SANET-MG] Fw: [SANET-MG] there's gold in them thar spuds



Hi Evon,
In the research article the gene to produce  beta carotene  leading to
vitamin A came from a bacterium. The genetic  engineering involved
insertion of two antibiotic resistance markers for kanamycin and for
rifamycin. Kanamycin is still used in human surgery and rifamycin is
used extensively to treat AIDs related tuberculosis. The selection of
markers was peculiar particularly as  rifamycin is used so extensively!
The situation on vit A birth defects is clear and even  beta carotene
has been implicated in a reported case of  Vitamin A toxicity.
The incidence of vit A birth defects was very significant until pregnant
women were advised to avoid vit A supplements and to watch their diet
for excessive beta carotene. Too little vitamin A may also cause birth
defects so the analogy to goldylocks porridge may be good. That is the
bear facts in the matter :-)
sincerely,joe

Evon Kochey wrote:

----- Original Message -----
From: "Evon Kochey" <sydney151@earthlink.net>
To: "Sustainable Agriculture Network Discussion Group"
<SANET-MG@LISTS.IFAS.UFL.EDU>
Sent: Sunday, November 21, 2004 6:16 PM
Subject: Re: [SANET-MG] there's gold in them thar spuds




Joe- I read the story in the times.  It says nothing about the


methods


used to genetically modify these potatoes.

I continue to be concerned about the use of antibiotic resistant
markers in the GM foods?  am I correct in assuming that with the
current state of genetic modification antibiotic resistant markers
would be required.

Evon




http://www.timesonline.co.uk/article/0,,2087-1368222_2,00.html

But how does a discovery in Dundee - which has so far produced only


a


few sackfuls of the new potato - make it into fields and foodbowls
across the Third World? For the next stage in the product's
development, Davies is looking to the richest businessman in the
world.

An international consortium led by Davies - with partners in


America,


China, India, South Africa and Denmark - has applied for a $7m


(£3.8m)


grant from the Bill and Melinda Gates Foundation's Grand Challenges


in


Human Health programme.

This is a $200m (£108m) fund set up by the Microsoft boss in January
2003 to find new ways to combat disease and malnutrition among the


two


billion poorest people on earth. As well as programmes to counter


HIV,


malaria and water sanitation, $20m (£10.8m) has been allocated to
"create a full range of optimal, bioavailable nutrients in a single
staple plant species".

Many of the applicants are expected to focus on rice and various
cereal crops. But the Scottish team believes potatoes will play an
important role and they understand their application is being looked
at sympathetically. An answer is expected just after Christmas.



----- Original Message -----
From: "jcummins" <jcummins@UWO.CA>
To: <SANET-MG@LISTS.IFAS.UFL.EDU>
Sent: Sunday, November 21, 2004 5:41 PM
Subject: [SANET-MG] there's gold in them thar spuds




The paper below was featured in today's sunday times.
The problem with beta  carotene and vitamin D  is that if it is


too


low


it is just public relations as in golden rice, if it is too high


you


face human birth defects and resulting lawsuites.
Like Goldylocks porridege, it has to be just right.
Journal of Experimental Botany, doi:10.1093/jxb/eri016 2004
RESEARCH PAPER

Metabolic engineering of high carotenoid potato tubers containing
enhanced levels of -carotene and lutein
Laurence J. M. Ducreux 1, Wayne L. Morris 1, Peter E. Hedley 2,


Tom


Shepherd 1, Howard V. Davies 1, Steve Millam 2, and Mark A. Taylor


1*


1 Quality, Health and Nutrition, Scottish Crop Research Institute,
Invergowrie, Dundee, DD2 5DA, UK
2 Gene Expression, Scottish Crop Research Institute, Invergowrie,
Dundee, DD2 5DA, UK

  Abstract

In order to enhance the carotenoid content of potato tubers,


transgenic


potato plants have been produced expressing an Erwinia uredovora


crtB


gene encoding phytoene synthase, specifically in the tuber of


Solanum


tuberosum L. cultivar Désirée which normally produces tubers


containing


c. 5.6 µg carotenoid g-1 DW and also in Solanum phureja L. cv.


Mayan


Gold which has a tuber carotenoid content of typically 20 µg


carotenoid


g-1 DW. In developing tubers of transgenic crtB Désirée lines,
carotenoid levels reached 35 µg carotenoid g-1 DW and the balance


of


carotenoids changed radically compared with controls: -carotene


levels


in the transgenic tubers reached c. 11 µg g-1 DW, whereas control


tubers


contained negligible amounts and lutein accumulated to a level


19-fold


higher than empty-vector transformed controls. The crtB gene was


also


transformed into S. phureja (cv. Mayan Gold), again resulting in


an


increase in total carotenoid content to 78 µg carotenoid g-1 DW in


the


most affected transgenic line. In these tubers, the major


carotenoids


were violaxanthin, lutein, antheraxanthin, and -carotene. No


increases


in expression levels of the major carotenoid biosynthetic genes


could be


detected in the transgenic tubers, despite the large increase in
carotenoid accumulation. Microarray analysis was used to identify


a


number of genes that were consistently up- or down-regulated in
transgenic crtB tubers compared with empty vector controls. The
implications of these data from a nutritional standpoint and for


further


modifications of tuber carotenoid content are discussed.

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