Effects Of Escherichia Coli With Different Activities Of β-G On The Output And Quality Of ECB

This studies consisted of four tests. In the test Ⅰ, the optimum condition forβ-glucuronidase(β-G) produced by Escherichia coli (E. coli)was determined by testing the activity of the enzyme under different conditions. In the test Ⅱ, the activities of β-G produced by five different serotypes of E. coli were examined. In the test Ⅲ was about the change rate of bilirubin from conjugated blilrubin(CB) to un-conjugated blilrubin(UCB) in the bile from slaughtered cattle with different serotypes of E. coli. In the test Ⅳ, the equal amount of two different serotypes of E. coli were mixed, then the activity of β-G, the change rate of CB, and the Output and Quality of the external Calculus Bovis(ECB) were respectively measured. The main results as follows:Test Ⅰ: The effect of factors on the activity ofβ-G produced by E. coliIn this test the influences of the temperature, pH, Ca2+ and ethylene glycol on the activity ofβ-G were examined. The results showed that rising temperature increased significantly the activity of β-G , the activity was the highest at 55℃ ,more over 4 times than one at 37℃ . The optimum pH of β-G was 7.0. 0.5mMol/L to 10 mMol/L Ca2+ might activate β-G, the activate has direct relationship with [Ca2+],and the most optimum concentration at 10 mMol/L. 0.3Mol/L to 3Mol/L Ethylene glycol could activate β-G and the most optimum concentration at 1.5 Mol/L.Test Ⅱ: Studies on the activity ofβ-G produced by five different serotypes of E. coliBased on the test Ⅰ, the test using the improved way of Fishman studied the activity of β-G produced by five different serotypes of E. coli, named as EcoⅠ,EcoⅡ,EcoⅢ,EcoⅣ,EcoⅤ,separately. The10ml,20mland 40ml solution with E. Coli(3.2×108/mL) was inoculated in 500ml bile. The results showed that the activities of β-G produced by EcoⅠand EcoⅡwere 120.20±11.68u/L and 117.30±10.73 u/L ,respectively,and were significantly higher than that of EcoⅢ,EcoⅣ,and EcoⅤ(P< 0.01),but there was no a significant difference between EcoⅠand EcoⅡ (p>0.05). The activities ofβ-G produced by EcoⅢ,EcoⅣ,EcoⅤwere 91.52±19.45u/L,30.41±14.12u/Land 29.11±11.32u/L, respectively. The activities ofβ-G produced by EcoⅢ was significantly higher than that of EcoⅣ,and EcoⅤ(P< 0.01),but there was not a significant difference between EcoⅣ and EcoⅤ(p>0.05). The amount of E. coli in the bile significantly decreased after 16th hour(P< 0.01),and the amount of E. coli in the bile had little impact on the results(p>0.05).Test Ⅲ: Studies on the change rate of CB with five different serotypes of E. coli The bile from slaughtered cattle(BSC) was sterilized by 60Co and the UCB in the bile was separated by adding to chloroform ,then the BSC was equally divided into five parts and tested the content of the total bilirubin(TB) and UCB. The five different serotypes of E. coli were individually inoculated into the BSC and incubated for 2 hours at 55℃,then the change rates of CB were examined. The results showed that the change rate of CB in the bile with EcoⅠand EcoⅡ were 57.14%±21.88% and 64.25%±26.83% , respectively, significantly higher than that of EcoⅢ or EcoⅣ(p<0.01).The change rate of CB in EcoⅢand EcoⅣrespectively were 28.57%±13.22% and 23.19%±11.33%,and the change rates of CB were much higher in the four strains of E. coli than that of EcoⅤ(p<0.01).Test 4 Effects of the mixture of E. coli with different activities ofβ-G on the output and quality of ECB EcoⅠand EcoⅡ,EcoⅠand EcoⅢ,EcoⅡand EcoⅢ were mixed with equal amount and named as EcoA,EcoB,EcoC, then the activity of β-G,the changing rate of CB, the weight of the precipitate in bile and the content of bilirubin and cholic acid in precipitate were tseted. The results showed that the activity ofβ-G produced by EcoⅠwas the highest and the sequence of the activity was EcoⅠ,EcoⅡ,EcoA,EcoⅢ,EcoB,EcoC and the non- E coli sample.The highest changing rate of CB was EcoⅠ,the result was 64.35%±15.36% and the lowest one was the non- E coli...