Eszett (ẞ; ß)-glucuronidase, a false positive of beta (β)-glucuronidase

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Short Communications | Published:

Print ISSN : 0970-4078.
Online ISSN : 2229-4473.
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Doi: 10.1007/s42535-022-00452-w
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Keywords: Biomarker, Enzyme activity, Errors, MUG (4-methylumbelliferyl β-d-glucuronide), Precision, PubMed, Reporter gene, Transgene expression, X-Gluc (5-bromo-4-chloro-3-indoxyl-β-d-glucuronic acid)


The Escherichia coli beta (β)-glucuronidase gene (GUS), coded for by the uidA gene, is a popular reporter gene in plant genetic transformation experiments. There are only two forms of GUS, alpha (α) and β. As a result of a typographic-type error, leading to confusion between Eszett (uppercase ẞ; lowercase ß), a German special character, and Greek lowercase beta (β), some published papers claimed to have used Eszett (ẞ/ß)-glucuronidase, which does not exist. A total of 79 plant science-related papers indexed on PubMed containing this error, i.e., false positive (ẞ/ß-glucuronidase), are highlighted. The error was detected in 100% of abstracts on PubMed and also in 100% of the abstracts on the original journal/publisher websites, while 62.0% of papers had this error in the text (once or multiple times). Errors in two other terms associated with plant genetic transformation, and related to false-positive GUS, namely 4-methylumbelliferyl β-d-glucuronide (MUG) and 5-bromo-4-chloro-3-indoxyl-β-d-glucuronic acid (X-gluc), were found in 5.1% and 24.1% of the 79 papers screened. A large-scale post-publication analysis of papers claiming to have used non-existent Eszett (ẞ/ß)-glucuronidase is needed. Those errors should be corrected.


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The author thanks Dr. Maria A. Smit, Managing Editor at Cold Spring Harbor Laboratory Press for kindly providing two full texts. This paper was preprinted at Research Square:

Author Information

Teixeira da Silva Jaime A.
Independent Researcher, Kagawa-ken, Japan