phages

2

SONIC UNIVERSE #74
The final showdown for the fate of the digital realm is HERE! “Spark of Life” Part Four: It’s pandemonium aplenty in this conclusion to the stunning “Spark of Life” story arc!  Who, or what, is Phage?  Introductions aren’t necessary—she’s creating havoc for our heroes anyway!  Tails and Big—menaced by badniks and Dark Gaia Monsters alike!  A Chaos Emerald—about to fall into enemy hands!  Nicole—on the brink of deletion!  Will Sally sacrifice it all to save her friends and the world? Only the dramatic conclusion to SPARK OF LIFE can tell! Featuring cover art from Sonic comic artist extraordinaire Tracy Yardley, and a special SEGA-art TAILS variant cover! 

On Sale: 3/18/2015

Fossilized human feces from 14th century contain antibiotic resistance genes

A team of French investigators has discovered viruses containing genes for antibiotic resistance in a fossilized fecal sample from 14th century Belgium, long before antibiotics were used in medicine. They publish their findings ahead of print in the journal Applied and Environmental Microbiology.

The viruses in the fecal sample are phages, which are viruses that infect bacteriai. Most of the viral sequences the researchers found in the ancient coprolite (fossil fecal sample) were related to viruses currently known to infect bacteria commonly found in stools (and hence, in the human gastrointestinal tract), including both bacteria that live harmlessly, and even helpfully in the human gut, and human pathogens, says corresponding author Christelle Desnues of Aix Marseille Université.

Fossilized human feces have been found in a cave in Oregon. The fossils are thought to be more than 14,000 years old.

  • A Boy Who Lost Everything
  • Case
Play

He wasn’t ready to attach himself to anything nice, or anyone nice for that matter. Then again, it would be stupid for him to wish to be alone after what he’d been through. He never hunted or provoked misfortune, but he was prone to surrender to it should it seem inevitable.

THE BACTERIOPHAGE — usually just called ‘phage’

  • An electron micrograph of the most abundant life-form on Earth
        the viruses that infect bacteria and replicate inside of them.
  • They’re one of the ways genes are transferred between bacteria.
  • Trillions of them inhabit each of us as part of our microbiome.

Colorized image by Department of Microbiology,
Biozentrum, University of Basel/Photo Researchers, Inc

Are viruses alive? Traditionally: no.
Are they biological entities? Well, they’re certainly important in the biosphere. Microbiologists study them, as do workers in other biomedical sciences.

Life-form = [1] a form of life; [2] something that is in the shape of life, that has the appearance of life  …

2

Your daily dose of Myoviridae TEM images:

Here’s a nice picture of some Myoviridae phage which infect Salmonella. Generally in the phage world, there are three more common families although others have been found:

  • Siphoviridae with long flexible tails. (P2 above)
  • Myoviridae with long contractile tails (T4 above)
  • Podoviridae with short non-contractile tails. (P22 above)

Phage are first classified based on their morphologies, but bioinformatic information shows the relationships between the families. Typically families of phage are grouped on their appearance as a large amount of the phage genome goes into making the structural proteins.

Myoviridae are quite interesting in the sense that when they bind their host, there are large visible structural changes in the tail region. The tail sheath contracts and the DNA is transported from the head into the bacterium. Other less visible mechanisms are present in the other two morphology types too.

Sam

youtube

Coming of Phage

Everything you’ve been taught about phage is wrong. Well, maybe not everything. Heck, maybe you’ve never been taught anything about phage in the first place! But if you’ve ever encountered a story about this family of bacteria-infecting viruses, I’m willing to bet it included a picture much like this:

That geometric lunar lander is the standard illustration of phage such as T7. It looks exotic and alien, a freakish example of biological symmetry, but it’s pretty true to the actual biology: The icosahedral protein head, the protruding neck that it uses to pierce the membrane of its victim so that it can inject its genetic material … and the legs.

Wait a sec, those legs need revising. Some really cool new research by Ian Molineux (who taught my graduate school molecular bio class, btw) says that all those “legs-out”, moon lander drawings of phage probably aren’t right.

In the video above you see that, according to the electron imagery they report in their Science paper, those legs stay tucked up next to the body for most of the free-floating life of the phage. It sort of drags one or two along, waiting to hook onto an appropriate bacterium that it can infect, at which point it extends the rest of the legs to go into full infection mode. To give you an idea of how hard this was to observe, a single phage is only around 20-30 nanometers wide, which means you could fit about 4,000 of them across the width of a single human hair!

It might seem like a small, ho-hum tidbit of research at first, since who really cares about a virus that infects bacteria? But phage are incredibly important. Phage have driven a great deal of the evolution of life on Earth. They are vehicles of gene swapping that have allowed genomes to expand and become more complex. They are veterans of 70+ years of biology research, from back when we first identified DNA as a genetic material to today’s exotic synthetic biology applications. A great deal of what we know about molecular genetics is because of these little guys, and we’re still making the most basic discoveries as to how they function.

Never let anyone tell you that there’s nothing left to discover! We have scarcely begun to fill in the colors, even for the most basic parts of biology’s palette.