Germ with seven motors in one!

by Jonathan Sarfati

Published: 15 January 2013 (GMT+10)

www.pnas.org

Over the last two decades, scientists have uncovered some of the amazing machinery in microscopic living cells. These include germs with a miniature motor that generates waves in a tiny tail that allows germs to swim—the bacterial flagellum.¹ This even turns out to have a clutch to disconnect the motor from the tail.² Even more miniaturized is the tiniest motor in the universe, ATP synthase, which makes the vital energy molecule ATP (adenosine triphosphate).³ Remarkably, a virus has a tiny motor used to wind up DNA into tight packages.⁴

Some germs have more than one flagellum. Sometimes they work individually but still the germ manages to coordinate the motors. Other germs have the tails loosely bundled. But the marine bacterium MO-1 is different again. Here, seven flagella are tightly bundled in a sheath.

The mystery was how they could all rotate in the same direction without interfering with each other. Now a research team from French and Japanese universities⁵ has worked out how. They produced a series of 2-dimensional images of cross sections to build up a 3-dimensional picture (electron cryotomography—like a CAT scan, but with an electron microscope and very cold temperatures).

The seven flagella are actually surrounded by 24 fibrils (tiny fibres), in a hexagonal array. And these fibrils rotate in the opposite direction to the flagella, allowing them to rotate freely. The researchers’ diagram shows the flagella as large gear wheels with the fibrils as smaller gear wheels. These gears or bearings enable the flagella to spin very fast—so the germ can swim about 300 μm/s, or 10 times faster than E. coli and Salmonella.

www.pnas.org

The researchers evidently had no use for evolution in their research. Instead, they referred to “complex and exquisite architecture”, and said:

“This design must be playing an essential role in the fast, smooth rotation of the flagellar apparatus that allows the rapid swimming of MO-1.”

But in the last paragraph, the researchers paid the obligatory fact-free homage to goo-to-you evolution:

“Taken together, these features of the MO-1 flagellar apparatus represent an advanced level of evolution of a motility apparatus. It is also intriguing that the same pattern of an intertwined hexagonal array in two evolutionary distant systems: the basal bodies of flagella and fibrils of the MO-1 flagellar apparatus, and the thick and thin filaments in vertebrate skeletal muscle. Similar architectures of filamentous structures presumably evolved independently in prokaryotes and eukaryotes to fulfill the requirements for two very distinct mechanisms to generate motion: counter rotation and axial sliding.”

This is yet another example of appealing to ‘convergence’: the same design feature allegedly evolved not just once but twice. But more to the point: in the late 1940s, the famous evolutionist J.B.S. Haldane predicted that we would find no wheels or magnets in living creatures.⁶ This is because these would not work unless fully formed. Thus natural selection could not have produced them step by small step, each an improvement over the previous one. Such motors thus falsify evolution by Haldane’s own words. MO-1 also senses magnetism,⁷ following Earth’s magnetic north pole in a helical path. So MO-1 provides two strikes against evolution.