送交者: xh 于 2005-11-09, 13:18:47:
1. To say a theory is partial right, and the only right part is on the observation is to say that the theory is wrong.
The major confilct between 细胞重建 and cell division is whether an existing cell is necessary for the formation of the new cell. We can always argue one way or the other, however, 细胞重建 has so many critical problems that it is obviously not true.
2. Materials to make new cells from an existing cell can only come from the existing cell. For an intact cell, only ways to change materials in it are endocytosis or exocytosis. Otherwise, whatever happens in the cell would not change the basic chemical components. New cells of course have to use the old materials to form under all circumstances.
However, 'Reformation' says cells can form from even intercellular spaces, i.e. materials outside of the cell. Sounds like in a bowl of soup, if you cook it right, would give you a living cell, or even a cow in the end. Then I would ask, where does all the information come from, how does the soup know it should be a cow instead of a snake.
3. The bottomline to me is what is 'A Cell'. In vitro oscillation of chromosome and chromatin structures mimiking what happens during cell cycle is a classical observation in cell cycle study. However, it is not quite the nucleus yet. To be alive, there are lots of other functions.
Every cell now a days carries an evolutionary history from the orgin of life. That is the information that determines what, where, when and how a cell should be. Life in a soup might have happened at the beginning of life because there had been virtually no information prior to that. However, that primitive 'life' has no comparison in terms of complexity to any of modern life form. Some people claimed they 'reformed' the primitive life form. But to claim to 'reform' a modern cell is just absurd.
4. As to drosophila eggs, I think it should still be considered 'one' cell after all the nuclear divisions. There are individual cells only after the membrane formed. That is when they can relatively independently 'mind their own businesses'. My own way of looking at it: a cell is something that you can take out from something a live and sustain its autonomous living function in an in vitro condition. Better still, to be able to put it back in to the organism without doing either of them any harm.