Dr. Delmer pioneered research on how cotton synthesizes cellulose, the primary compound in its fibers. She wanted to see evidence that the researchers’ novel molecules formed stable chemical bonds with cellulose. If they didn’t, she said, “then the prospects that they can survive harsh treatments when incorporated into fabrics would seem less certain.”
Filipe Natalio, lead author of the study and a scientist at the Weizmann Institute of Science in Israel, said his team had similar concerns. He and his colleagues used chemical and physical analytical techniques to show that the cellulose in the fibers had undergone changes.
But that’s not the same as showing that the new molecules were chemically woven, via enzymatic reactions, into strands of cellulose, Dr. Delmer said. Instead, Dr. Natalio’s team could just be picking up signatures of their molecules hanging out in the cells, but not forming long-term linkages.
Dr. Natalio responded that English is not his native language, and to him, words like “incorporated” or “integrated” covered the possibility that the molecules got into the cotton fibers without binding to its components. “We didn’t claim also that there were linkages,” he said. Given limited room to explain every last detail in the paper, he continued, “we had to make a lot of sentences that were very vague” and “encapsulate information without proving it, which is awkward.”
Beyond being unconvinced of the paper’s central claim, cotton researchers were skeptical about whether Dr. Natalio’s system would ever evolve past proof of concept. He spoke in an interview about a not-so-distant future with cotton and other plants growing in hydroponic greenhouses, bathed in fluids with all sorts of customized molecules.
But Dr. Natalio and his colleagues were experimenting with small amounts of cotton embryos in the lab, not whole plants. Dr. Natalio acknowledged that for the technology to work with actual plants, he would have to synthesize whole new sugars, “one of the most delicate chemistries you can do.”
Moreover, Dr. Natalio’s group found that the modified fibers they produced were actually weaker than raw cotton fibers. That’s a big no-no in the cotton industry, since it “wreaks havoc in yarn production” and goes against the durability consumers want from cotton, said Don Jones, a director of agricultural research for Cotton Incorporated, a trade organization based in North Carolina.
Cotton experts also noted that the authors cultured their cotton for an unusually short amount of time, many experiments presented in the paper had no information on replication and there were statistics missing in places one might expect to find them. Mislabeled chemicals in two supplemental figures led Science to publish its editorial expression of concern.
Several experts wondered if the people involved in the peer review of the study were materials scientists, chemists or physicists, not biologists.
When asked what fields the editors and reviewers for this study belonged to, the journal said in an email that Science papers are assigned to a staff editor who “identifies the types of expertise needed to evaluate all aspects of the manuscript under consideration,” but offered no specifics.
Two of the three biologists who are experts in cotton only agreed to speak on the condition of not being named, out of concern that publicly raising questions about other scientists’ work could boomerang on their careers. One of them spotted the misnamed chemicals and contacted Science, leading to the journal’s expression of concern about the paper.
Ivan Oransky, co-founder of Retraction Watch, a site that reports on problems with scientific research, said the researchers’ concerns were understandable, but “in the long term it’s bad for science if researchers are not willing to have public, respectful debates.”
He added that there are ways to make the peer review process more transparent, like having journals publish reviewers’ reports and editorial decisions along with articles.
Dr. Natalio said his team is preparing a list of corrections to be attached to the article. He added that they have preliminary data that suggests the stable chemical linkages that Dr. Delmer had wanted to see. But he refrained from putting that data in this paper because it was incomplete and he believed it would prolong the review process.
One of the rules of publication? “Don’t claim what you can’t prove,” he said.
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