As the Holiday Season approaches, millions of us will be out in the malls looking for that special gift for family, friends and colleagues. While the hunt may prove challenging for many, for others, another requirement of the gift-giving process may lead to untold stress: the gift wrap. While a number of successful methods exist, the actual execution of this task can be painful.
In the microbial world, gift wrapping -- better known as cellular packaging -- is also considered to be an art. All germs perform some aspects of packaging but the masters are without a doubt the viruses. Viruses are unique from all other germs in that they don't start to thrive until they have entered a host cell. They are akin to gift packages that float around in the environment - and in the body. On the inside, there is an assortment of microscopic goods, such as genetic material and proteins. On the outside, the wrap, better known as a capsid, serves as both protection and also disguise.
When a virus meets a host cell, there is no indication that there is anything other than treats on the inside. The cell might then decide to welcome the virus hoping for the best. Unfortunately, there is nothing friendly about the exchange and when the capsid opens, the cell is more than likely doomed to die.
Over the last decade, researchers have been acting in the same vein as Oprah and Martha Stewart to better understand how viruses are able to wrap themselves so effectively and cause so much damage. Some have proposed models to explain the wrapping process while others have examined the history of virus gift-wrapping to find any clues to their success.
In 2010, two researchers from the Catholic University of America and the University of Maryland revealed how one particular type of virus, known as a bacteriophage or a virus of bacteria, had a similar means to those fancy gift wrappers we see in the shopping malls. Not only did they have the capsid, but they also were decorated with two molecules that acted as the equivalent of gift bows.
These proteins, known as Hoc and Soc, provide extra padding and also a molecular sheen to the virus making them irresistible to their hosts. Yet, while this helped to understand how bow-laden phages may work to make a bacterium's life miserable, there was still no clear explanation for human viruses.
In 2012, there was a partial answer found by a group from Indiana University. The team looked at how a type of animal virus, enterovirus, formed its capsid shell, which is known to be one of the toughest known to exist. What they found was that unlike our normal view of gift wrapping, which is primarily based on one sheet of paper forming a cube or cylinder, these viruses used a number of pieces of gift-wrapping protein to form a 3-dimensional structure known as a dodecahedron. But what was even more fascinating was that inside each of these pieces was an intricate molecular structure that rivaled origami.
A year later, a team from the University of Michigan took this one step further by showing these artful creations were unique to each protein and that each virus could have different types of adornments. This would mean that even if a cell met with two of the same viruses, there would be enough difference between the wraps that the cell would accept both. Unfortunately, unlike accidental duplicate gifting in the human world, there is no possibility for a gift exchange afterwards.
Based on the combination of molecular bows and origami, finding the perfect means to gift wrap a virus might never be possible. But recently, an international collaboration of researchers worked together to find the right model such that the mechanics of virus gifting might be finally understood. Using computerized models of a number of different viruses, such as bacteriophages, yeast, plant, animal and human viruses, the group spent countless hours trying to find a common pathway for successful gift wrapping.
To accomplish this, they virtually unwrapped and re-wrapped viruses in the hopes that they would find a method that would work for all. Eventually, they were able to find an equation that worked both in theory and practice although its name, Quasi-Rigid Domain Decomposition, might not make it on either Martha or Oprah's gift wrapping guides anytime soon.
The increasing knowledge on how viruses can offer cells the best gift package -- at least on the outside -- may eventually help to keep you from getting sick whilst trying to find more human-themed gifts. December is a tough month for many as colds and flus make their way into the noses and lungs of millions leaving many sick and less than happy for the holidays.
Researchers may one day be able to change the nature of the gift wrap or find ways to block the interaction with our cells, such that we may never have to worry about going shopping again. Unfortunately, even with Quasi-Rigid Domain Decomposition, there may never be a way to make everyone the perfect gift wrapper.