For decades , researchers recollect that Ellen Price Wood - feed insects rely entirely on their helpful germ to reveal down the problematic cellular phone walls of plant life . lately , cellulase , an enzyme that digests the cadre rampart polymer cellulose , was discovered in pin insects themselves . Now , fit in to a newInsect Biochemistry & Molecular Biologystudy , walking sticks in the order Phasmatodea give rise cellulases that can take down several types of cell wall polymers equally .
The complex polymers in plant cellphone paries – such as cellulose , xylan , and xyloglucan – typically require several different enzyme ( cellulases , xylanases , and xyloglucanases , for representative ) to amply break them down into their component part sugar . Yet all stick insects verbalise multiple , different cellulase enzymes from the glycoside hydrolase family 9 ( GH9 ) – nearly half a 12 cistron copy per species . Why inherit multiple copies of gene for cellulase , and why have Phasmatodea genomes preserved all these GH9s over evolutionary time ? maintain superfluous enzyme does n’t make much sense if they all have the same function .
A Max Planck Institute for Chemical Ecology team lead byMatan Shelomihypothesized that some written matter evolved new or extra function to cellulase activeness that would increase the worm ' power to digest leaves . So they isolated cellulase genes from six stick louse species – who live as far as Australia , Vietnam , Borneo , Peru , and Madagascar – as well as one sister mathematical group calledTimema cristinae . The squad verbalize their case-by-case GH9 enzyme , then tested them against various plant life cell bulwark polymer .
Turns out , in increase to the glucose backbone of cellulose , some of their enzymes can also break down the xylose backbone of xylan , while others target the xylose - glucose backbone of xyloglucan . " If we had n’t tested these enzyme on other substrates besides cellulose , there was no way we could have get word these functions , " Shelomi state in astatement . " It was full that we did : Nobody come up these kind of herculean enzyme in an animal before . " This is the first time xyloglucanase of any kind was found in a multicellular animal , and it suggests that spliff insects can derive more aliment from the same plant dieting than any other herbivore .
Furthermore , because these multifunctional enzymes were also found inTimema cristinae , that think an hereditary cellulase gene – from before the Phasmatodea evolve – had duplicated into several gene , and some run on to evolve fresh abilities .
