Teenage mu­tant space bac­te­ria

Wangaratta Chronicle - North East Regional Extra - - News - WITH CHRIS FEBVRE,

FOR­GET Face-Hug­gers, Zenomorphs and Trif­fids, the real threat from outer-space might just be earth­born bac­te­ria that has hitched a ride to our space sta­tions.

Ac­cord­ing to re­cent, and very in­ter­est­ing, re­search con­ducted by the Univer­sity of Hous­ton, Texas, E. coli bac­te­ria that trav­els into low or zero grav­ity en­vi­ron­ments be­comes heav­ily mu­tated over a short span of time.

In the long­est study yet of bac­te­ria in sim­u­lated mi­cro-grav­ity, the re­searchers found that the adap­ta­tions which had de­vel­oped over 1000 gen­er­a­tions of the or­gan­isms (quite a short span of time when it comes to bac­te­ria) re­mained even when the re­searchers tried to erase them.

While in the low grav­ity en­vi­ron­ment, genome se­quenc­ing re­vealed that the bac­te­ria had de­vel­oped 16 mu­ta­tions, the most no­table of which was its abil­ity to form biofilm - colonies of cells that are em­bed­ded in pro­tec­tive slime that makes the bac­te­ria hardier.

But re­searchers are un­sure of the func­tions of some of the other mu­ta­tions.

“We are, in fact, see­ing true ge­nomic changes – per­ma­nent changes,” says team mem­ber Ge­orge Fox at the Univer­sity of Hous­ton.

“We can see which genes are mu­tat­ing, but we don’t know what they’re do­ing ex­actly.”

Af­ter giv­ing the cells time to adapt in mi­cro­grav­ity, the team at Hous­ton then com­bined them with an­other strain of E. coli that had not been sub­jected to such an en­vi­ron­ment.

They found that the mi­cro­grav­i­ty­mu­tated bac­te­ria grew at three times the rate of the reg­u­lar bac­te­ria.

In other words, not only was the Space-E.coli harder to kill, it grew much faster as well.

“This study is broader in scope than pre­vi­ous ones on two counts,” says Ja­son Rosen­zweig at Texas South­ern Univer­sity.

“It’s look­ing at a much longer tra­jec­tory and it’s also in­ter­ro­gat­ing the en­tire genome rather than spe­cific sub­sets of genes.”

Even af­ter the bac­te­ria was re­moved from mi­cro­grav­ity for 30 gen­er­a­tions be­fore be­ing com­bined with the reg­u­lar strain, it still re­tained 72 per cent of their adap­tive ad­van­tage, which in­di­cated to the re­searchers that it wasn’t merely of short term adap­tive boost, but per­ma­nent mu­ta­tions in the genes.

While the E.coli strains the sci­en­tists were deal­ing with were rel­a­tively in­nocu­ous, the mu­tated strain could po­ten­tially cause a prob­lem if it at­tached it­self to a space sta­tion’s life sup­port sys­tem.

“We need more of this kind of ex­per­i­ment, espe­cially with hu­man space flight gain­ing more trac­tion in re­cent years,” said re­search leader Mad­han Tiru­malai.

Tiru­malai’s chief con­cern is that if E.coli can mu­tate at an ac­cel­er­ated rate in mi­cro­grav­ity, other more harm­ful bac­te­ria such as sal­mo­nella might do the same.

And given that as­tro­nauts’ im­mune sys­tems are weak­ened in space, the threat of par­tic­u­larly vir­u­lent bac­te­ria is of sig­nif­i­cant con­cern.

The good news is that while the cells grew faster and were less af­fected by their en­vi­ron­ment, the E.coli was still just as sus­cep­ti­ble to an­tibi­otics.

Re­searchers at the Univer­sity of Hous­ton, Texas have dis­cov­ered that E. coli bac­te­ria ex­posed to a mi­cro­grav­ity en­vi­ron­ment (such as in­side a space sta­tion) mu­tate rapidly and grow at three times the rate of the same strain on Earth.

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