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Updated: Aug 14, 2026

Site-Specific Lysine Lactylation via Genetic Code Expansion in E. coli and Mammalian Cells
Published on: February 24, 2026
Genetic Construction of Lactose-Utilizing Xanthomonas campestris
P M Walsh1, M J Haas, G A Somkuti
1Agricultural Research Service, Eastern Regional Research Center, U.S. Department of Agriculture, Philadelphia, Pennsylvania 19118.
Abstract:
Xanthomonas campestris, the producer of xanthan gum, possesses a beta-galactosidase of very low specific activity. Plasmid pGC9114 (RP1::Tn951), generated by the transposition of the lactose transposon Tn951 to RP1, was conjugally transferred into XN1, a nalidixic acid-resistant derivative of X. campestris NRRL B-1459S-4L. Transfer occurred on membrane filters and in broth. The beta-galactosidase gene of Tn951 was expressed in X. campestris. The specific activity of beta-galactosidase in transconjugants was over 200-fold higher than that in XN1, and transconjugants grew as well in lactose-based media as in glucose-based media. The lactose-utilizing transconjugants could potentially be used to produce xanthan gum from cheese whey.
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