Sperm Gets Cold Shoulder

Now GE may cause the inability of the sperm to fuse with the egg. Genetically modified (GM) carrots and potatoes have been imported into NZ, these vegetables contain an unstable transgene containing a zona pellucida (ZP) antigen and a LT-B protein to enhance the absorption of the antigen. This antigen when eaten crosses the intestinal wall and then circulates around the blood stream. The antigen then causes an auto-immune response causing antibodies to ZP to be formed. These antibodies will then go on to attack the undeveloped egg in the follicles of the ovary. It has been found that human ZP is 85% similar to possum and pig ZP. Researcher, Koyama (1996) injected pZP into hamsters causing permanent infertility followed by degenerative changes in the ovaries. In monkeys there was also ovarian impairment with pre-cancerous cells.

Why worry.....because an antigen to the zona pellucida has been created?

The zona pellucida (ZP) is a jelly that every mammalian female egg cell has enclosing it. It is a compound of three glycoproteins that acts as; an attraction to the sperm, a help for binding sperm to the egg and once the egg is fertilised a repellent to other sperm. It also acts to protect the egg from chromosomal damage and to promote fertility. All ZP jelly is specific and essential to each species. If this form of possum control is allowed to become commonplace, horizontal gene transfer (HGT) across species could infer long term sterility to all the female populations of animals both marsupial, bird, bovine, ovine and homo-sapiens. How would this happen?

It is acknowledged that possums are major carriers of TB. They transfer the toxin to the soil through their faecal waste and dead bodies. Cows dogs and other animals can pick the disease is up if they contact the waste. There is no guarantee that possums would not transfer the ZP antigen through their faeces into the soil in this manner. Research studies have found that, “Humans and mice fed on potato expressing the sLT-B protein produced antibodies against LT-B in their serum and gut secretions” (Mason et al. 1998; Tacket et al. 1998). Therefore, GE Free NZ suggests that ERMA should have prohibited the release of possums to the outdoor facility/pens.

ERMA has allowed 13 such decisions to reach the field without any scientific reviewed information counteracting the concerns of the NZ public. The risk to the NZ environment and economy through poor science with no insight to the precautionary principle, is leading New Zealand agriculture close to the brink of a disaster. So maybe the least worry is the sperm being left in the cold!

References

Skinner,SM,:Mills,T.:Kirchick, H.J; Dunbar, B.S.; (1984) Immunisation with zona pellucida proteins results in abnormal ovarian follicular differentiation and inhibition of gonadotrophin-induced steroid secretion. Dept Cell Biol; Baylor Coll. Med., Houston, TX, USA.

Rankin Tracy; Talbot, Prue; Lee, Eric; Dean, Jurrien.(1999) Abnormal zonae pellucidae in mice lacking ZP1 result in early embryonic loss. Laboratory of Cellular and Development Biology, NIDDK, National Institutes of Health, Bethesda, MD, USA.

Cai,L; Li, D; Sun, X; Wang, M. (2000). Mechanism of prmature ovarian failure in murine autoimmune oophoritis immunised by porcine zona pellucida.Institute of Obstetrics and Gynecology, Shanghai Medical University, Shanghai, People Rebublic of China.

Abington Reproductive Medicine.(2000) Association of antizona pellucida antibodies in human premature ovarian failure and infertility. www.abington-repromed.com

Koyama, K.; Hasegawa, A.; Isojima, S.(1994) Porcine zona pellucida antigen 4(ZP-4) as a candidate for vaccine. Department of Obstetrics and Gynecology, Hyogo Medical College, Hyogo, Japan.Eds. Talwar, G.P.; Rao, Kanury V.S.; Chauhan V.S. Recomb. Synth. Vaccines.

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