Phytoecdysteroids larvae

20-Hydroxyecdysone and other ecdysteroids are used in biochemistry research as inducers in transgenic animals, whereby a new gene is introduced into an animal so that its expression is under the control of an introduced ecdysone receptor . Adding or removing ecdysteroids from the animal's diet then gives a convenient way to turn the inserted gene on or off (see ecdysone receptor ). At usual doses, 20-hydroxyecdysone appears to have little or no effect on animals that do not have extra genes inserted; it also has high bioavailability when taken orally, so it is useful for determining whether the transgene has been taken up effectively. [4] For uses in gene therapy , it may be necessary to investigate more thoroughly the natural sources of ecdysteroids in humans (which appear to include dietary phytoecdysteroids , gut flora , helminth infections , and other diseases ). [5]

Using pure phytoecdysteroids isolated from Ajuga iva (L.) Schreber (Lamiales: Lamiaceae) and Silene nutans L. (Caryophyllales: Caryophyllaceae), plants known for their high ecdysteroid content, a study was carried out on the effects of ingestion of four different phytoecdysteroids (20-hydroxyecdysone, polypodine B, ponasterone A and makisterone A) on the growth and development of the Indian meal moth, Plodia interpunctella Hübner (Lepidoptera: Pyralidae) larvae when added at a concentration of 200 ppm in their diet. The experiments clearly showed the susceptibility of P. interpunctella to phytoecdysteroid ingestion. The toxicity of phytoecdysteroids manifested itself by a decrease in larval weight, induction of cannibalism and an increase of mortality, together with disruption of development. The severity of the phytoecdysteroid effect on P. interpunctella depended on the structure of the molecule. The results demonstrate that the minimal structural differences existing between these four phytoecdysteroids significantly affected their toxicity toward P. interpunctella. Makisterone A was the most toxic of the four compounds towards P. interpunctella larvae. In conclusion, phytoecdysteroids ingestion evokes disruptive growth effects on P. interpunctella. This work supports a role for phytoecdysteroids in plant defence against phytophagous insects.

Phytoecdysteroids larvae

phytoecdysteroids larvae

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