RESUMEN
Aim: To determine the biocidal efficacy of THPS based biocides currently used in oil fields to control souring and corrosion. Methodology: By direct monitoring of inhibition of cell growth and inhibition of microbial functional group activities such as the ability to reduce sulfate and generate sulfide by sulfate reducing bacteria (SRB), reduce nitrate to nitrite by heterotrophic nitrate reducing bacteria (hNRB) and oxidation of sulfide and reduction of nitrate by sulfide oxidizing, nitrate reducing bacteria( so-NRB) using CSB-K medium. Results: We observed that higher doses of THPS (>400 ppm) was required to considerably inhibit the ability of SRB to reduce sulfate and generate hydrogen sulfide. It was also observed that the activities of SRB were more affected by the THPS biocides than those of hNRB and so-NRB. Conclusion: We conclude that SRB may have developed low level microbial resistance to THPS based biocides as higher doses are required to inhibit their activities. It is therefore recommended that THPS should be used in combination with other biocides or metabolic inhibitors for it to be effective at lower concentrations.
RESUMEN
Objective:To investigate the suppressed e ects of total hedysarum polybotrys saccharide(THPS) alone and THPS combined with Cytoxan(CTX) on tumor-bearing mice and its mechanisms.Method:Kunming mice inoculated with S180 were given low,moderate and high dose THPS and THPS combined with CTX by intraperitoneal injection.Fourteen day later,tumor weight,inhibition rate,thymus index and spleen index were observed.CD4+ and CD8+ lymphocyte were counted though the ow cytometer.Results:Compared with the control,the moderate dose THPS showed signi cantly suppressed e ect on the growth of S180 tumor(P
RESUMEN
Objective To study the efficacy and toxicity of tetrakis(hydroxymethyl)phosphonium sulfate(THPS)in indoor air disinfection.Methods The orthogonal experiments were employed with three factors including concentration of THPS,temperature and time,and four levels including the concentrations of THPS,0.05%,0.1%,0.5%,1%,and the temperature,15℃,20℃,25℃,30℃,and the time,2 h,4 h,8 h,16 h.The germicidal effect of THPS with those factors was assessed.Using modified method,Daphnia magna straus(Cladocera crustacea),Brachydanio rerio,mice were randomly divided into 5 dose groups and a control respectively.For Daphnia magna straus(Cladocera crustacea),123.03 mg/L,134.90 mg/L,147.91 mg/L,162.18 mg/L and 177.83 mg/L,for Brachydanio rerio,42.66 mg/L,57.54 mg/L,77.62 mg/L,104.71 mg/L and 140.90 mg/L,for mice,183.60 mg/kg,293.75 mg/kg,470.00 mg/kg,752.00 mg/kg and 1 203.20 mg/kg.The data for 2th,4th and 7th day of treatment were collected for calculation of the 48h-EC50,the 96h-LC50 and the acute oral LD50 in Daphnia magna straus(Cladocera crustacea),Brachydanio rerio and mice.Results The maximal germicidal rate of THPS in indoor air was over 86%.At the concentration of 0.5% THPS,4 h reaction time,germicidal efficacy of THPS was optimal.The toxicity test indicated that the acute oral LD50 for mice was 492.72 mg/kg,the 48 h-EC50 for Daphnia magna straus(Cladocera crustacea)was 143.61 mg/L,the 96h-LC50 for Brachydanio rerio was 84.17mg/L.Conclusion The toxicity of THPS is low and can be used for indoor air disinfection with a good efficacy and the potential benefit for environment.