In other animals, quickly growing tissues, such as tumors and embryos, are thought to get this energy from glycolysis– the items of which can be used to build biomass more quickly than other forms of ATP production.So when Andrea Wills, a biologist at the University of Washington, and her team started looking into what fuels tail regeneration in tadpoles, they expected to find that tadpoles shuttle glucose into this metabolic pathway too, Wills says.Their first experiment appeared to bear this out. “We simply kept putting on more of these inhibitors and they didnt do anything,” she says.So the scientists started browsing for alternative metabolic paths that take in glucose. They looked for increased expression of other genes and discovered higher levels of all however one enzyme used in the pentose phosphate path (PPP). Glucose feeds into the pentose phosphate path (PPP) (3 ).
PDF © NICOLLE FULLER, SAYO STUDIOThe PPP makes NADPH, a molecule utilized to construct fatty acids, and ribose-5-phosphate, a nucleotide precursor. Wills states it makes good sense that the pathway would be upregulated because “if youre going to be a proliferative tissue, you will need to make lots of brand-new membrane out of fatty acids, [and] youre going to need a great deal of nucleotides” for DNA.Caroline Beck, a developmental biologist at the University of Otago in New Zealand who was not included in the work, states that the authors “have done a great job” providing a compelling story, however warns that “these pathways cross-talk with each other all the time, so its quite tough to rule [a pathway] in or out totally.””One of the long-lasting goals,” Wills states, “is to be able to utilize this knowledge to boost regenerative results in individuals,” but she includes that by itself, turning on the PPP probably wouldnt offer cells regenerative capability. “You need to have development … and patterning, and you also have to have inhibition of the scarring reaction … One of the aspects that weve been missing out on is how to allow development.” The PPP may be vital to allowing that growth.