Saddle Up Your Algae: Scientists Harness Flagellar Motors

1805: Beast of burden of choice: oxen.
2005: Beast of burden of choice: algae.
Science Now reported an unusual item: scientists have learned how to hitch their loads to a single-celled green alga named Chlamydomonas reinhardtii (see Yale description).  Researchers are actually calling their little teams “micro-oxen.”

Scientists are increasingly interested in harnessing biological motors for use in micro- and nanotechnology, but recent research has mainly involved taking moving parts out of cells and adapting them for use elsewhere.  It’s a complicated process that can require protein engineering.  So, chemist Doug Weibel of Harvard University in Cambridge, Massachusetts, and colleagues wondered if they could simply use an intact organism as a beast of burden instead.   (Emphasis added in all quotes.)

This alga contains whiplike flagella that propel them through liquid like motorized paddleboats (see U of Wisconsin description).  “These algae are very reliable,” Weibel said.  See also the BBC News report.
    In other flagellum news, Howard Berg of Harvard, writing in Current Biology,¹ described how bacterial flagella (the rotary kind) receive feedback from the environment: “the flagellum senses wetness,” he reported.  The wetness of the environment affects antagonistic regulatory proteins that control flagellum production.  Research by Q. Wang et al. found that a suppressor is “pumped out of the cell by the flagellar transport apparatus once assembly of the basal part of the flagellum is complete,” Berg said.  What for?  “This prevents the cell from wasting energy on flagellin synthesis when this protein cannot be put to use.”  The scientists sprinkled a little water on dry colonies for 90 seconds and, sure enough, got them to produce more and longer flagella that exhibited normal swarming behavior.  Berg describes it: “Swarming is a specialized form of bacterial motility that develops when cells that swim in broth are grown in a rich medium on the surface of moist agar.  The cells become multinucleate, elongate, synthesize large numbers of flagella, secrete surfactants and advance across the surface in coordinated packs.” 

¹Berg, Howard, “Swarming Motility: It Better Be Wet,” Current Biology, Volume 15, Issue 15, 9 August 2005, Pages R599-R600.

The intelligent design movement could get a load of this.  It was amazing enough that some flagella are built like high-tech rotary motors.  For humans to harness that power and use it underscores the claim that these really are molecular machines.  It’s there; it works; why reinvent the wheel?