title: Stable expression of Escherichia coli beta-glucuronidase A (GusA) in Giardia lamblia: application to high-throughput drug susceptibility testing.
abstract: OBJECTIVE
  In order to create a suitable model for high-throughput drug screening, a Giardia lamblia WB C6 strain expressing Escherichia coli glucuronidase A (GusA) was created and tested with respect to susceptibility to the anti-giardial drugs nitazoxanide and metronidazole.
  
  
  METHODS
  GusA, a well-established reporter gene in other systems, was cloned into the vector pPacVInteg allowing stable expression in G. lamblia under control of the promoter from the glutamate dehydrogenase (gdh) gene. The resulting transgenic strain was compared with the wild-type strain in a vitality assay, characterized with respect to susceptibility to nitazoxanide, metronidazole and -- as assessed in a 96-well plate format -- to a panel of 15 other compounds to be tested for anti-giardial activity.
  
  
  RESULTS
  GusA was stably expressed in G. lamblia. Using a simple glucuronidase assay protocol, drug efficacy tests yielded results similar to those from cell counting.
  
  
  CONCLUSIONS
  G. lamblia WB C6 GusA is a suitable tool for high-throughput anti-giardial drug screening.
authors.affiliation: Institute of Parasitology, University of Berne, Berne, Switzerland. joachim.mueller@ipa.unibe.ch
authors.forename: Joachim
authors.initials: J
authors.lastname: Müller
authors.forename: Dorothea
authors.initials: D
authors.lastname: Nillius
authors.forename: Adrian
authors.initials: A
authors.lastname: Hehl
authors.forename: Andrew
authors.initials: A
authors.lastname: Hemphill
authors.forename: Norbert
authors.initials: N
authors.lastname: Müller
mesh_terms: D000818:Animals; D000981:Antiprotozoal Agents / Q000494:pharmacology; D004353:Drug Evaluation, Preclinical / Q000379:methods*; D004926:Escherichia coli / Q000201:enzymology* / Q000235:genetics; D029968:Escherichia coli Proteins / Q000096:biosynthesis* / Q000235:genetics; D017930:Genes, Reporter; D016829:Giardia lamblia / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics; D005966:Glucuronidase / Q000096:biosynthesis* / Q000235:genetics; D008795:Metronidazole / Q000494:pharmacology; D008826:Microbial Sensitivity Tests; D050296:Microbial Viability; D009574:Nitro Compounds; D004364:Pharmaceutical Preparations; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000235:genetics; D013844:Thiazoles / Q000494:pharmacology
chemical_list: D000981:Antiprotozoal Agents; D029968:Escherichia coli Proteins; D009574:Nitro Compounds; D004364:Pharmaceutical Preparations; D011994:Recombinant Proteins; D013844:Thiazoles; D008795:Metronidazole; D005966:Glucuronidase; C041747:nitazoxanide