Life is endlessly surprising: "The diverse bacteria were found in groundwater and are thought to be quite common. They're also quite odd, which isn't a surprise given the cells are close to and in some cases smaller than several estimates for the lower size limit of life. This is the smallest a cell can be and still accommodate enough material to sustain life. The bacterial cells have densely packed spirals that are probably DNA, a very small number of ribosomes, hair-like appendages, and a stripped-down metabolism that likely requires them to rely on other bacteria for many of life's necessities."
The rule I fashioned for myself when I first studied viruses at the low, molecular genetics level, was that if they can exist, they probably will. They especially are "hacks", and I'm sure it'll be interesting to see what's learned from these bacteria.
The smallest virus is 17 nm in diameter, according to Wikipedia. Most are 20 to 300 nm. The bacterium here is about 500 nm across, almost exactly the wavelength of visible light.
Not really my area, but I'd guess the smallest viruses are a lot smaller. They don't have to function at all, just deliver a packet of genetic material to a target. So they don't have to be very large, just that genetic material plus stuff to protect it and to get into the target and attack.
"To concentrate these cells in a sample, they filtered groundwater collected at Rifle, Colorado through successively smaller filters, down to 0.2 microns, which is the size used to sterilize water. The resulting samples were anything but sterile".
Could "sterile" water be potentially dangerous then?
