Viruses challenge our definition of life. Neither dead nor alive, they are simply functional or not. Viruses do not possess the machinery to replicate themselves. Yet you can even argue that they are more evolved than us. With each discovery about viruses, we realize there is so much more to learn.
10. Black Widow Virus
Scientists have recently discovered a virus containing the gene for black widow poison.
The WO virus specifically targets Wolbachia bacteria in arthropods. Latrotoxin kills by poking holes in cell membranes. It is believed that the venom genes allow the WO virus to break through cells and evade the host's immune system. This is the first time animal genes have been seen in bacteriophages—bacteria-targeting viruses.
Experts hypothesize that the virus picked up the genetic material after breaking out of a Wolbachia bacterium into a black widow cell. However, it is possible the spider stole the gene from the WO virus.
9. Infertility Virus
A mysterious viral infection may be the cause of half of unexplained cases of infertility. In one-quarter of infertility cases—roughly one in 70 women under the age of 44—doctors cannot find a cause. An Italian research team discovered that a virus in the herpes family is to blame. It causes immune reactions that make the womb inhospitable for an embryo. Customized anti-viral treatment could offer help.
The team studied 30 mothers and 30 women with unexplained infertility. 13 of the infertile women were infected with HHV-6A. None of the mothers had it. This herpes variety was discovered over 30 years ago but remains a mystery. HHV-6A infection releases estradiol hormone, which triggers ovulation and prepares a womb for fertilization.
8. Survivor Virus
Scientists have recently unlocked the secrets to a virus that can survive boiling acid.
The SIRV2 virus infects a microbe called Sulfolobus islandicus, which lives in acidic hot springs where temperatures top 80 degrees Celsius (175 °F). Using a Titan Krios electron microscope to examine the specimens in previously unimaginable detail, scientists have unlocked the basic mechanism of resistance to heat, desiccation, and ultra-violet radiation.
SIRV2 forces genetic material into a protective structural state called A-formation to survive extreme conditions. The mechanism is remarkably similar to the spores bacteria form to survive such environments. These spores are known to cause hard to combat diseases like anthrax. Scientists plan on using these survival mechanisms to design a DNA package for gene therapy.
7. Multicomponent Virus
Normal viruses have all their genes in one viral particle. This viral ball attaches to a cell, opens, and injects its genetic material inside. The host cell begins replicating the virus. Once enough copies are made, they kill the cell, break free, and infect more.
The Guaico Culex virus is different. To become infected, a cell needs to be exposed to four varieties of packages. A fifth appears optional.
Named after the region in Trinidad it originated, Guaico Culex was discovered during a comprehensive study by the US Army Medical Team to isolate mosquito-borne viruses around the globe. While researchers do not believe Guaico Culex virus can infect mammals, they recently discovered a closely related variety in Uganda's red colobus monkeys.
6. Human Endogenous Retrovirus
Roughly 8 percent of the human genome comes from ancient viruses. Retroviruses reproduce by inserting their genetic material into a host and hijacking its replication machinery. Occasionally, these viruses infect sperm and egg cells. If these cells survive, they go on to create an organism containing the virus's DNA in every cell. These are referred to as endogenous retroviruses—in humans, HERVs. The vast majority are considered non-functional "fossils." However, a small portion are still intact and can make infectious particles.
