Tuesday, March 27, 2007

Revisiting organismal complexity

Once it was thought to be proportional to the size of the genome. Then, we found that most of the genome of some organisms was apparently doing nothing since it did not code any proteins, so it was postulated that organismal complexity was proportional to the number of genes. Thus, it came as shock that we humans, of all organisms, had a relatively modest number of genes with respect to our intuitive notion of complexity.

Nowadays people talk of the regulatory interactions between genes as the true key to organismal complexity. According to this view, intricate regulation and not sheer number of proteins should reflect the complexity of an organism.

A relatively new player in this mind-game is miRNA. Strong evidence suggests that microRNAs are effectors of an intricate, fine-tuned regulatory network that acts combinatorially on mRNA transcripts. And, according to some estimates, more than half of the coding genes of vertebrates have their expression modulated by microRNAs.

An excellent introduction to this topic can be found here.

And let there be light

Commonly used lab bacteria called E. coli can be converted into light-harvesting organisms in a single genetic step, according to new research from MIT. The genetic enhancement allows microorganisms that normally derive their cellular energy from sugars to switch to a diet of sunlight. These findings could ultimately be used to genetically engineer bacteria that can more efficiently produce biofuels, drugs, and other chemicals.

Read more

Wednesday, March 14, 2007

Another dimension...

Have you heard about this work? It reports the first 3D reconstruction of a complete eukaryotic cell volume, the fission yeast Schizosaccharomyces pombe, by electron tomography. How amazing!

This high-resolution, three-dimensional image of a eukaryotic cell was created by researchers led by Claude Antony of the European Molecular Biology Laboratory in Heidelberg, Germany. They scanned 250-nanometre-thick slices of frozen fission yeast and assembled the scans into a computer-generated 3D image.

Neglected and Orphan Tropical Diseases?!

Last week, in my lab meeting we laughed at the existence of a journal called 'PLoS Neglected Tropical Diseases' which is the first open-access journal devoted to the neglected tropical diseases (NTDs).

So, I was curious, and I tried to find what diseases are charaterized this way. And why! I'm writing this post because I thought this could be a great topic of discussion.

There are 13 tropical diseases considered to be 'neglected', because not enough money is spent on researching and/or distributing cures (e.g., leprosy). I've read that the 13 all have some fundamental traits in common, not in terms of their biology, namely:
  • Ancient afflictions that have burdened humanity for centuries
  • Poverty-promoting conditions
  • Associated with stigma
  • Rural areas of low-income countries and fragile states
  • No commercial markets for products that target these diseases
  • Interventions, when applied, have a history of success

  • But, do you know what I also found interesting? The open-source 'Tropical Disease initiative' also refers to Orphan Diseases (illnesses on which phamaceutical companies tend to do little research)! They argue that there is an overlap between 'neglected' and 'orphan' diseases, but the latter group includes TB and malaria.

    By the way, do you know that some people argue that malaria is
    not a tropical disease? World largest outbreaks of malaria in recent time occured in siberia and norway in the 19th Century!