title: Amelioration of cadmium- and mercury-induced liver and kidney damage in rats by genetically engineered probiotic Escherichia coli Nissle 1917 producing pyrroloquinoline quinone with oral supplementation of citric acid.
abstract: OBJECTIVE
  Antioxidants, chelating agents, and probiotics are used to manage the toxic effects of cadmium (Cd) and mercury (Hg). The aim of this study was to investigate the combined effects of antioxidants, chelating agents, and probiotics against heavy metal toxicity.
  
  
  METHODS
  Genetically modified probiotic Escherichia coli Nissle 1917 (EcN-20) producing a potent water soluble antioxidant pyrroloquinoline quinone (PQQ) was supplemented with oral citric acid and compared with another genetically modified probiotic EcN-21 producing PQQ and citric acid against oxidative stress induced by Cd and Hg. Rats were independently given 100 ppm Cd and 80 ppm Hg in drinking water for 4 wk.
  
  
  RESULTS
  EcN-20 was found to be more effective than EcN-2 (EcN strain with genomic integration of vgb and gfp genes) with orally given PQQ against oxidative stress induced by Cd and Hg. EcN-20 supplemented with oral citric acid was more effective against Cd and Hg toxicity compared with EcN-2+citric acid (oral), EcN-2+PQQ (oral), EcN-2+PQQ (oral)+citric acid (oral), EcN-20, and EcN-21. However, protection shown by EcN-21 was similar to EcN-20.
  
  
  CONCLUSIONS
  The combination therapy involving probiotic EcN-20 producing PQQ with citric acid given orally was found to be a moderately effective strategy against toxicity induced by Cd and Hg, whereas the protective effect of EcN-21 was the same as EcN-20.
authors.affiliation: Department of Biochemistry, Faculty of Science, The Maharaja Sayajirao University of Baroda, Gujarat, India.
authors.forename: Ruma
authors.initials: R
authors.lastname: Raghuvanshi
authors.affiliation: Department of Biochemistry, Faculty of Science, The Maharaja Sayajirao University of Baroda, Gujarat, India.
authors.forename: Archana
authors.initials: A
authors.lastname: Chaudhari
authors.affiliation: Department of Biochemistry, Faculty of Science, The Maharaja Sayajirao University of Baroda, Gujarat, India. Electronic address: gnaresh_k@yahoo.co.in.
authors.forename: G Naresh
authors.initials: GN
authors.lastname: Kumar
mesh_terms: D000284:Administration, Oral; D000818:Animals; D000975:Antioxidants / Q000008:administration & dosage; D002104:Cadmium / Q000633:toxicity*; D002614:Chelating Agents / Q000008:administration & dosage; D019343:Citric Acid / Q000008:administration & dosage / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D005818:Genetic Engineering; D007668:Kidney / Q000187:drug effects* / Q000293:injuries / Q000378:metabolism; D008099:Liver / Q000187:drug effects* / Q000293:injuries / Q000378:metabolism; D008297:Male; D008628:Mercury / Q000633:toxicity*; D045542:PQQ Cofactor / Q000096:biosynthesis* / Q000235:genetics*; D019936:Probiotics / Q000627:therapeutic use*; D051381:Rats
chemical_list: D000975:Antioxidants; D002614:Chelating Agents; D002104:Cadmium; D019343:Citric Acid; D045542:PQQ Cofactor; D008628:Mercury
keywords: Cadmium; Citric acid; Heavy metal toxicity; Mercury; Probiotic E. coli Nissle 1917; Pyrroloquinoline quinone