April 22, 2008

Ken Miller: Intelligent Design

Posted in Mad Scientist, Policy tagged , , , , , , at 4:38 am by D. Borst

In the below video, (its about 2 hours 70 minutes long, with 50 minutes of questions) Ken Miller of Brown University shows the intellectual pitfalls that are faced by Intelligent Design. It was originally posted 2 years ago, but his points are no less important today than they were then. If you have ever found yourself mystified at how to intelligently and coherently respond to ID advocates, then take a look at this video. Ken Miller nicely skirts the line between respecting those who believe in God yet still maintaining scientific rigor. If you have a spare 2 hours, check it out. It is good.

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October 29, 2007

Mad Scientist: Update on Chloroplasts

Posted in Mad Scientist at 10:54 pm by D. Borst

So it turns out that a natural experiment has developed that tests exactly what I questioned in my last mad scientist post– Sea Slugs ingest algae and are able to extract the chloroplasts from these cells and use them to fix their own carbon.  These sea slugs only extract the chloroplasts though, and they are able to use the products of the fixation reaction in their own bodies.  Cool!  Read about it in this article here. Free article from NCBI.

October 21, 2007

Mad Scientist Dreams: Chloroplasts in Animal Cells

Posted in Cell Biology, Mad Scientist at 8:07 am by D. Borst

So animals cells need the universal energy currency ATP just like plant cells. We animals get our ATP from the catabolic processing of carbohydrates and fats. Which is really, really cool, as I will go over in another post. Plants, as every 3rd grader learns, use chloroplasts to generate high energy electrons (in the form of NADPH) which are then used to make ATP through oxidative phosphorlation. But for the first episode of Mad Scientist’s Question Period, what would happen if you were to insert chloroplasts into an animal cell, or even just a eucaryote that normally doesn’t contain them? Would the cell be able to attain the ATP generated by the chloroplasts? Chloroplasts, like mitochondria have transferred many of the genes for their machinery to the host genome, but even in the absence of this information the chloroplast should be able to last for a while. Does this sort of transgenic cell work? Furthermore, would it be possible to insert the genes for chloroplasts into the genome of a mouse or a nematode and get a photosynthetic animal?

I am trying to approach the issue of modularity in genetics and cell biology. Some aspects of cellular life appear to be fairly modular–they can be mixed and matched between organisms with relative ease, adding features without disrupting the symmetry of the pattern. In my mind, lateral gene transfer in prokaryotes is a prime example of this.

For example, the genes of an ABC transporter that confers drug resistance can be transferred from one prokaryote to the next, making the spread of drug resistance much faster than it would be if microbes followed a strictly hereditary system of evolution. But the point is, the gene for the transporter protein can be transferred to a new type of bacteria through lateral transfer, and the protein can be expressed and implanted in the membrane, where it will serve its function without necessarily gumming up the rest of the organisms works.

Now the chloroplast is a much larger and more complex possible “module” than a single Transporter Protein, and multicellular eucaryotic cells are much more complex than prokaryotic cells. It is very likely that this wouldn’t work at all. But it sounds to me like a question for science.

Any papers describing an attempt at such a crazy task would be greatly appreciated.