Anti-E. coli Beta Glucuronidase Polyclonal antibody

To express a human lactoferrin (hLF) gene in Bacteroides uniformis, a member of the anaerobic microflora in the colon, we constructed a recombinant plasmid, pVLFK, by subcloning hLF cDNA to an Escherichia coli-Bacteroides shuttle vector, pVAL-1. The plasmid pVLFKwas transferred to B. uniformis strain BU1001 by the filter mating procedure creating strain TCTK101. The lactoferrin protein in B. uniformis strain TCTK101 was detected by Western blot analysis with an anti-human lactoferrin monoclonal antibody. A culture of strain TCTK101 inhibited the growth of E. coli strain HB101 in vitro compared to a culture of strain TCTK11, which is a B. uniformis strain-carrying plasmid pVAL-1, suggesting that the lactoferrin produced from strain TCTK101 possesses biological activity. To determine the effect of lactoferrin-producing B. uniformis on the formation of azoxymethane-induced aberrant crypt foci (ACF), putative neoplastic lesions, overnight cultures of strains TCTK11 and TCTK101 were given to rats as drinking water. The numbers of ACF and ACF having more than three crypts per focus five weeks after the beginning of the experiment significantly increased in the group treated by a culture of strain TCTK11 compared with those in the non-treated water group. However, rats treated with a culture of strain TCTK101 carrying plasmid pVLFK showed a significantly lower number of ACF than rats with a culture of strain TCTK11 (34% reduction), suggesting that hLF which is produced in a prokaryotic expression system prevents formation of ACF in the rat colon. (C) 2001 Academic Press.

This study was conducted to develop a screening method using Colilert-18 and a device for the detection of E. coli from agri-food production environments and fresh vegetables. The specificity and sensitivity of Colilert-18 by temperature (37 degrees C and 44 degrees C) were evaluated with 38 E. coli and 78 non-E. coli strains. The false-positive rate was 3.8% (3/78) and 0% (0/78) at 37 degrees C and 44 degrees C, respectively. The detection limit of E. coli at 37 degrees C at <1.0 log CFU/250 ml was lower than that at 44 degrees C. The efficiency of the developed device, which comprised an incubator equipped with a UV lamp to detect E. coli in the field, was evaluated by measuring the temperature and UV lamp brightness. The difference between the set temperature and actual temperature of the developed device was about 1.0 degrees C. When applying the developed method and device to various samples, including utensils, gloves, irrigation water, seeds, and vegetables, there were no differences in detection rates of E. coli compared with the Korean Food Code method. For sanitary disposal of culture samples after experiments, the sterilization effect of sodium dichloroisocyanurate (NaDCC) tablets was assessed for use as a substitute for an autoclave. The addition of one tablet of NaDCC per 50 ml was sufficient to kill E. coli cultured in Colilert-18. These results show that the developed protocol and device can efficiently detect E. coli from agri-food production environments and vegetables.