化学论文翻译

Until now, no article reported the identification and quantification ofP. aeruginosa using MSPQC.In this article, a new acetamide broth was developed for identificationand quantification of P. aeruginosa by MSPQC. It was based on the factthat P. aeruginosa can grow well in a medium using acetamide as nitrogenand carbon source (Noel and Holt 1984; Smith and Dayton 1972). Veryfew bacteria can do this. During the process of growing P. aeruginosa,the conductivity of the medium changed and was automatically monitoredby MSPQC. Frequency detection time (FDT), which is defined as time atwhich oscillating frequency shift of MSPQC changed rapidly, has a linearrelationship with the logarithm of concentration. It is a parameter toquantitatively determine P. aeruginosa by MSPQC sensor.EXPERIMENTALBacterial IsolationPseudomonas aeruginosa (ATCC 9027), Staphylococcus aureus (ATCC12600), Acinetobacter baumannii (ATCC 19606), Escherichia coli (ATCC11775), and Pseudomonas maltophilia (ATCC 13637) were obtainedfrom Third Xiangya Hospital of Central South University, China.All the species were inoculated on blood plate (purchased fromGuangdong Huankai Microbial Science and Technology Co. Ltd.) at37C for 18 h, respectively. Then, three loops of each species in pureculture were transferred into a 100-ml sterilized conical flask containing50 ml of sterilized nutrient broth (NB). After incubation for 18 h at37C, the conical flask was removed from the incubator and preservedin a refrigerator as a stock solution. The concentration of stock solutionwas determined by pour plate counts (PPC) method.Composition of MediaThe composition of acetamide broth is acetamide (2.00 g=L), monopotassiumphosphate (0.4 g=L), sodium chloride (0.2 g=L), magnesium sulfate(0.1 g=L), sodium molibdate (0.05 g=L), and iron sulfate (0.005 g=L);pH is 7.2. The broth was autoclaved at 121C for 15 min.The composition of acetamide agar is acetamide (10 g=L), sodiumchloride (5 g=L), dipotassium phosphate (1.39 g=L), monopotassium phosphate(0.73 g=L), magnesium sulfate (0.50 g=L), phenol red (0.012 g=L),and agar (20 g=L); pH is 7.2. The medium was autoclaved at 121C for15 min.60 F. He et al.Downloaded By: [CAS Consortium] At: 03:09 20 April 2009ApparatusMSPQC system (Fig. 1a) consists of eight culture bottles (Fig. 1b) andeight oscillator circuits, shared universal frequency counter, computer,and temperature control system. The details of the instrument have beenpreviously reported (He et al. 2006).MSPQC MethodCulture bottles were placed into MSPQC system and incubated at 37C.Each culture bottle contained 9ml of acetamide broth and 1ml ofP. aeruginosa suspension. The online curves of frequency shift (DF) vs.culture time could be seen on screen by using self-developed software.