Thursday, January 6, 2011

What is Life? Evolution from invertebrates to vertebrates 7(無脊椎動物から脊椎動物への進化その7)

Good morning everyone. I am sorry, it was new year's holiday till yesterday. Did you have the first dream, which means the destiny of the year? I have not haven it yet, but I could make real plan to rebuild my life with my friend. This might be one of the biggest thing for my life.


Anyway, let's start again. Until the last class, Sammy introduced the finding of the activity of thyroid hormones for the metamorphosis in sea urchin larvae. The result supposed that the hormone controls the metamorphosis of sea urchin larvae. However we could not identify the origin of the hormone, because the algae as food for the larvae contained the hormone at some level. We had to elucidate the origin to identify whether the factor is the hormone or not.


For such problems, Professor Amemiya at Tokyo University suggested for us to use of non-feeding larvae. The eggs of Peronella Japonica contains large amount of yolk. So the larvae does not feed. Furthermore, the alimentary tract does not been developed into a thoroughly canal. Because the larvae does not feed, if the amount of the hormone increased in the larval body, the origin is suggested as endogenous products. It's called as hormone.


By these results showed tree things. First, the thyroid hormones accelerates metamorphosis of sea urchin larvae containing the development of the adult rudiment and the resorption of the larval body. Second, such thyroid hormones are synthesized in the larval body as endogenous factors. Third, such hormonal control of metamorphosis were occurred at some kinds of echinoderms as invertebrates.


The next class shows the conclusion of this course with the biggest report.


Today's class is over. Have a nice day. Click the button at the bottom of this "What is Life?", if you are a student of this class. Mind you? If you have any question about life, please send an e-mail for me.


にほんブログ村 科学ブログ 生物学・生物科学へ人気ブログランキングへ



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