The ignored virus that causes liver cancer

Hepatitis G virus was identified in 1995. Some little research was carried out on the virus and the US Food and Drug Administration (FDA) declared it a non-harmful virus in 1997. Researchers in Saudi Arabia, writing in the International Journal of Immunological Studies present evidence to suggest that this may have been the wrong decision. They claim that transmission of the virus through donated blood that was not screened for the virus as well as infection through other routes has led to an increase in cirrhosis of the liver and liver cancer.

Hepatitis G virus (HGV) was renamed as GB virus C (GBV-C) and is a virus in the Flaviviridae family but has not yet been assigned to a genus. Intriguingly, some evidence suggests that co-infection with the AIDS virus, HIV, somehow enhances the immune system in those patients. However, it is the effects of the virus on the livers of otherwise healthy patients that is of concern to Mughis Uddin Ahmed of the King Abdulaziz Hospital (NGHA) in Al-Ahsa, Saudi Arabia. He points out that since the FDA declared the virus not to cause health problems to humans in 1997, no donated blood has been screened for this virus.

However, Mughis Uddin Ahmed has carried out a review of the scientific literature for the last 16 years that show the virus to be quite prevalent around the globe. Moreover, there is a correlation with infection with this virus and hepatitis, cirrhosis of the liver and it is possibly linked to hepatocellular carcinoma. Mughis Uddin Ahmed also found an apparent link with hematological disorders and hematological malignancies.

For this reason, he suggests that research should be carried out into this virus to determine whether it is a true human pathogen and a viral carcinogen. He also advises that screening of donated blood for this virus should be reinstated urgently rather than healthcare workers continuing to transferring the virus ignorantly to blood recipients and risking the same morbidity and mortality outcomes seen with hepatitis C virus transferred from donor to recipient until screening for that virus was adopted.

Ahmed, Q. (2011). Hepatitis G virus (HGV): where we stand and what to do? International Journal of Immunological Studies, 1 (3) DOI: 10.1504/IJIS.2011.041723

It’s life Jim, but not as we know it

Would we recognize life if we found it on other planets? Are the weird imaginings of decades of science fiction writers enough to provide the necessary clues for finding ET?

Exobiology is an odd field of science. Research in this fascinating field relies on one of the biggest assumptions we make about the universe – that we are not alone, that there could be life on worlds other than the Earth. However, while life on earth is incredibly diverse, fundamentally, almost every single species of plant, virus, fungus, bacterium, fish, mammal, insect boils down to one of two nucleic acids – DNA or RNA. There is no reason to presume that life on another planet would use molecules resembling the nucleic acids. So, any discussion of exobiology always comes back to that first question – would we recognize alien life if we saw it?

Professor John A. Baross

Professor John A. Baross

A new report published by the US National Research Council (NRC) suggests that scientists focus at least some of their efforts on weird life, that is, the possibility of life that does not confirm to the standard terrestrial chemical blueprint. The NRC team suggests that the fundamental requirements for life on Earth – liquid water, as a biosolvent, carbon-based metabolism, molecular system capable of evolution, and the ability to exchange energy with the environment – may not be the only biochemical options for life. Our investigation made clear that life is possible in forms different than those on Earth, explains committee chair John Baross, of the University of Washington, Seattle.

The report states that the discovery of extraterrestrial life would have an enormous and inspirational impact on our position in the cosmos, but nothing would be more tragic than if we failed to recognize it.

Life elsewhere in the universe needn’t resemble life on earth.

Life elsewhere in the universe needn’t resemble life on earth.

Until now, the search for ET, has homed in on putative habitats that share at least some of the features of Earth, such as liquid water. However, Baross and his colleagues suggest that other liquids such as ammonia or formamide could also work as biosolvents, although the biochemistry of an organism using those materials would inevitably be very different. That said, Saturn’s moon Titan is thought to have a liquid water-ammonia mixture within and so is close to the top of the list of likely homes for weird life beyond Earth.

It is critical to know what to look for in the search for life in the Solar system, explains Baross, The search so far has focused on Earth-like life because that’s all we know, but life that may have originated elsewhere could be unrecognizable compared with life here. Life forms that use a replication chemistry unrelated to nucleic acids could well exist, there are suggestions that spiral entities that form spontaneously from cosmic dust, replicate and change, could be defined as somehow alive. There is also perhaps the entirely non-carbon organisms of science fiction fame, the silicon-based lifeform. It looks like a rock, Jim but double check those vital signs on the tricorder just in case

Further reading

The Limits of Organic Life in Planetary Systems
http://www.nap.edu/catalog.php?record_id=11919

Professor John A. Baross
http://oceanweb.ocean.washington.edu/ocean_web/about/faculty/profiles/BARJOF.html

Suggested searches

astrobiology
extraterrestrial life

Spherical chemical

The outer shells of viruses and other biological systems assemble themselves spontaneously from identical sub-units composed of proteins coded for by the organism’s genes. This way, a simple set of instructions can build a complex and functional structure.

Now, Makoto Fujita and colleagues Masahide Tominaga, Keisuke Suzuki, Masaki Kawano, and Takahiro Kusukawa at The University of Tokyo, Shigeru Sakamoto, and Kentaro Yamaguchi at Chiba University and Tomoji Ozeki of Tokyo Institute of Technology have used this natural approach to construction to help them develop self-organizing spherical networks of organic molecules. Such supramolecular compounds might be useful as catalysts, sensor molecules, or to help extract other smaller molecules from mixtures.

Makoto Fujita

Makoto Fujita

The team knew from their earlier work, that short, rod-shaped molecules with sticky ends that can join to metal ions can form two-dimensional grids with the metal ions forming the corners of a grid of the rod-like molecules. There is no theoretical limit on the size of these grids. Fujita reasoned that banana-shaped rods might link up similarly but rather than forming infinite flat grids, they would form curved surfaces. The team used biphenyl-based compounds and mixed them with the noble metal palladium. The result was the spontaneous formation of large, spherical structures with diameters of about 4 nanometres.

The researchers then analysed their spheres using NMR spectroscopy and showed that each acts like a single large molecule. They could also crystallize the spheres and so carry out an X-ray diffraction study to determine the exact structure, showing that each sphere contains twelve metal centres and 24 organic units.

Masahide Tominaga

Masahide Tominaga

The next step was to alter the surface of the spheres by adding functional groups, or ligands, as attachment points to the metal centres. Fujita and his colleagues have, for example, added porphyrin systems to these ligands. Porphyrins are well-characterised nitrogen-containing molecular rings with a metal at their centre found in light-absorbing proteins and in the chlorophyll of plants and blue-green algae. A porphyrin system is also present in the blood pigment haemoglobin, which carries, transports and exchanges oxygen and carbon dioxide. Fujita’s team reason that such modifications to their spheres could enable them as light-gathering systems or as sensor units for different gases.

Rod for sheets, bananas for balls (Adapted from Wiley/VCH by David Bradley)

Rod for sheets, bananas for balls (Adapted from Wiley/VCH by David Bradley)

The crystal structure of a self-assembled sphere (Credit: Wiley/VCH)

The crystal structure of a self-assembled sphere (Credit: Wiley/VCH)

Banana-shaped molecules could ring the changes for chemists (Photo by David Bradley)

Banana-shaped molecules could ring the changes for chemists (Photo by David Bradley)

Further reading

Angew. Chem. Int. Ed. 2004, 43, 5621-5625
http://dx.doi.org/10.1002/anie.200461422

Fujita Lab
http://fujitalab.t.u-tokyo.ac.jp/index_e/

Ozeki Group
http://www.cms.titech.ac.jp/~ozeki/index-e.html