Painting the invisible

Watercolor of Mycoplasma mycoides by David S. Goodsell, the Scripps Research Institute.

Section through a eukaryotic cell here.

From the department of amazing facts

Notes [1] today:

• The flagellar motors in a bacterium such as Escherichia Coli rotate at up to 18,000 revolutions per minutes. Each rotation is powered by the flow of about 1,000 hydrogen ions across the inner membrane. The motor can turn the flagellum in either direction, clockwise or anticlockwise, on demand. 
  
• E coli cells push their way through water about at 30μm/s -- that is, 10 or 15 times their body length. [2] (That's roughly equivalent to a human moving at 65 to 97.5 km per hour.) But when they stop turning the flagella, the don't keep coasting as a ship or submarine would. Instead, the surround water stops them in less than the diameter of a water molecule, less than a ten thousandth of their length. [3]

Footnotes

[1] from The Machinery of Life by David Goodsell

[2] 1μm is 0.001 mm -- a millionth, or 10^-6 , of a metre

[3] A water molecule is 3x10^-10 metre (A Sense of Scale) 

'Overcome by an astonishment at being me'

We can contrast two distant relatives: the intestinal bacterium Escherichia coli and its host, ourselves. We span the spectrum of complexity in living organisms: the bacterium has minimal capability for perceiving and reacting to short term changes in its environment, whereas the major portion of our body is devoted to these tasks.

E coli commit less than 5% of their molecular machinery to motion and perception, allowing the simplest responses...Our bodies, in contrast, are built for specific, directed motion under the control of detailed, reasoned perception. The bulk of our body weight is dedicated to sense, reaction and motion. Cells in our retina are filled with arrays of opsin proteins for sensing light, light that is focused by layers of eye lens cells packed full of clear crystallin proteins. Cells in our skin spin enormously long strands of keratin protein into hairs, and other cells sense their slightest movement. These and other sensory data are transmitted and processed by nerve cells that carry electrical currents propagated by proteins and insulated by concentric layers of lipid. Fine control of movement is accomplished by an enormous skeleton of mineralized bone cells, moved by muscle cells filled with proteins that do nothing but contract, all glued together by connective tissue cells that build tough layers of sugar and protein. However, the common thread of life on Earth still shows through the diversity, tying the simplicity of the bacterium to the complexity of our bodies. All of these unique molecular machines are built of the same four molecular components -- proteins, nucleic acids, lipids, and polysaccharides.

-- from The Machinery of Life by David S. Goodsell.

The title of this post is from an essay by Ken MacLeod. See also In the Waiting Room by Elizabeth Bishop.

An inordinate fondness for microbes

By one rough estimate there may be 150 million species of microbes.

In years to come scientists hope to have genomes of about 1,500 analyzed for a new encyclopedia.

"It's a dent, but a small dent".

-- from Catologing the vast world of microbes.

Little wonders

Two of the stories in the news:

Microbes survive 30,000 years inside a salt crystal

Working as a team, bacteria spin gears

Bugs do it

...co-operate and cheat, that is:

An increasing body of empirical evidence suggests that cooperation among clone-mates is common in bacteria. Bacterial cooperation may take the form of the excretion of “public goods”: exoproducts such as virulence factors, exoenzymes or components of the matrix in biofilms, to yield significant benefit for individuals joining in the common effort of producing them...Moreover,...this synergism opens up a remarkably rich repertoire of social interactions in which cheating and exploitation are commonplace.

-- from Czárán T, Hoekstra RF, 2009 Microbial Communication, Cooperation and Cheating: Quorum Sensing Drives the Evolution of Cooperation in Bacteria. PLoS ONE 4(8): e6655. doi:10.1371/journal.pone.0006655

In the big picture, co-operation prevails. As Richard Fortey puts it, most of history has been conducted inside bacterial mats:

Sealed in slime from the cruelty of ultraviolet radiation, mats formed mounds, and columns, and pillows, and fingers; mats formed great cones in the deeper sea, the like of which have not been seen on Earth for 1,500 million years. Ultimately, mats maketh man.

Tummy bugs

Because bacteria can evolve so fast, it may be that some of what we think of as human evolution — like the ability to digest new diets that accompanied the invention of agriculture — is actually bacterial evolution. We know that hostile bacteria — those that cause diseases in ourselves and our domestic plants and animals — have undergone dramatic genetic changes in the last 10,000 years. Perhaps our friendly bacteria have, too.

-- from Microbes R Us by Olivia Judson.

Nature's smartdust

Communication, decision making, 'city living', accelerated mutation, navigation, learning and memory.

-- Six reasons 'why microbes are smarter than you thought.'

Remarkable though these behaviours are, we have probably only scratched the surface of what single-celled organisms can do. With so many still entirely unknown to science, there must be plenty more surprises in store.

Stentor