Monday, September 27, 2010

What is Life? 変態について(その4)


There were two things, which were both very sad and happy in my life. So, I could not open the class of What is Life? in these days. I am very sorry. But in those days, there was an incredible  news. The Tigers may be won in this season as a champion of the central league, is't it? It' too great for me. There may be a God as a "Life"?


Ok! I shall start also today! Today is the 4th about Metamorphosis. In the 3rd class, I explained that the larval body is melted down in the pupa. Here, I show about the future of their life (^_^).


The worm became to the pupa by control of the hormone, and the larval body was melted down by the activity of some protease. Therefore, when the pupal body of silk worms or beetles were injured by yourself, the white body fluid was leaked from the larval body. Of course, the pupa must be die by the reason. What was happen in the body of the pupa?


As you may think, all was not be melted down in the pupa's body. The process to be an adult is going on in the body. And also, you know that the stem cells have ability to differentiate to various cell types. In the truth, the egg has same character like such stem cells, and fertilized egg differentiate to all cell types to develop to be "Life". So the fertilized egg is a kind of embryonic stem cell. (Can you understand this joke?) Anyway, such cells in the larval body were called as "adult rudiments". They are waiting for "the Time".

蛹の中で溶けた幼虫細胞は、栄養になります。そして、成虫原基はそれを栄養として成長し、そして成虫の体を蛹の中で再構築するのです。この仕組みほど難解なものはございません。嘗て、世界一の発生生物学者Eric Harley Davidsonは1995年のScience誌に、"Origin of Bilaterian Body Plans: Evolution of Developmental Regulatory Mechanisms"という論文を発表しました(PMID: 7481819)。論文の詳細は、ご覧になっていただくとして、当時、まだ「幹細胞」という概念すら無かったその時代に、彼は"Set aside cells"(他所で置いておかれた細胞群)という考えを発表しています。この驚くべき論文は、サミぃの人生を大きく変えることとなる訳です。

The melted body fluid in the pupa was used as a source and energy to rebuild the adult body. This is the most interesting theme or mechanism in Developmental Biology. Many researcher are trying to elucidate the problem "What is Metamorphosis". One of the greatest researcher in the developmental biology area showed an article in Science at 1995. The title is following "Origin of Bilaterian Body Plans: Evolution of Developmental Regulatory Mechanisms"(PMID: 7481819). The article had changed my life.


Today's class is over. Be careful. It is rainy and cold. Please click the button at the bottom of this What is Life?, if you are a student of this class.

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

1 comment:

  1. 早速グラスを掲載して頂きまして有り難うございます!


Thank you!