Retraction

Cell Biology. In the article “Lipochitooligosaccharide-induced tobacco cells release a peptide as mediator of the glycolipid signal” by Michael John, Jürgen Schmidt, Richard Walden, Inge Czaja, Marion Dülz, Jeff Schell, and Horst Röhrig, which appeared in number 19, September 16, 1997, of Proc. Natl. Acad. Sci. USA (94, 10178–10182), the undersigned authors wish to note the following: “We cannot repeat critical experiments reported in this paper and therefore we wish to retract the article. We apologize for any inconvenience that publication of this study may have caused.”