Re: Can chloroplasts cause a person to become green in colour?

Hi Leow!

I very much doubt that the chloroplasts would survive long in a human cell. It is very likely that either 1) the cell will die, or 2) the chloroplasts would be destroyed by autophagy, i.e. by being taken up in a lysosome in the cell and digested. So I think it is very unlikely that you could turn someone green by injecting their cells with chloroplasts.

Having said that, let me tell of a very interesting case of an animal that can take up chloroplasts. There are some sea slugs, shell-less gastropods (snails), which do exactly that. The best studied example of this is Elysia chlorotica, a ascoglossan mollusk found in intertidal marshes on the east coast of the US. This sea slug resembles a green leaf (see: http://www.seaslugforum.net/display.cfm?id=1969).

The Elysia feeds on filamentous algae like Vaucheria litorea by piercing the cell wall and sucking out the cell contents, including the algal chloroplasts. The sea slug digestive tract has many out-pocketings (diverticula) in which digestion takes place. However, unlike the rest of the algal cell contents, the chloroplasts are not digested, but are in fact taken up intact into cells lining the digestive diverticula. This is why the Elysia is green. These chloroplasts carry out photosynthesis, and may remain active up to 9 months! This “symbiosis” raises many questions, as it is generally accepted that in plants the chloroplasts are strongly dependent upon the plant cell nucleus for the coding for many of the proteins required for chloroplast function.

Hope that helps!

Karl Wilson, Ph.D.
Professor of Biological Sciences