ABSTRACT
Little information is available regarding the effectiveness of water disinfection by CO(2) at low pressure. The aim of this study was to evaluate the use of high levels of dissolved CO(2) at 0.3-0.6 MPa for the inactivation of microorganisms. Bacteriophage T4 was chosen as the model virus and Escherichia coli was selected as the representative bacterium. The results of the study showed a highly effective log inactivation of E. coli and bacteriophage T4 at low and medium initial concentrations by high levels of dissolved CO(2) at 0.3 MPa with a treatment time of 20 min. When the pressure was increased to 0.6 MPa, inactivation of both microorganisms at high initial concentrations was improved to different extents. Neither pressurized air nor O(2) effectively inactivated both E. coli and bacteriophage T4. The pH was not a key factor affecting the inactivation process by this method. The results of scanning electron microscopy of E. coli and transmission electron microscopy of bacteriophage T4 suggested that "CO(2) uptake at high pressure and bursting of cells by depressurization" were the main reasons for lethal effect on microorganisms. This technology has potential for application in the disinfection of water, wastewater, and liquid food in the future.
Subject(s)
Bacteriophage T4/drug effects , Carbon Dioxide/pharmacology , Disinfectants/pharmacology , Disinfection/methods , Escherichia coli/drug effects , Microbial Viability/drug effects , Bacteriophage T4/growth & development , Bacteriophage T4/metabolism , Carbon Dioxide/metabolism , Disinfectants/metabolism , Escherichia coli/growth & development , Escherichia coli/metabolismABSTRACT
We have established a continuous cell line from the fat body tissue of the longicorn beetle Plagionotus christophi. The cells have been serially subcultured in MGM450 medium, and the line has been designated as PC-1. The cells were grown in suspension and comprise largely flattened spindle- or oval-shaped cells morphologically related to blood cells of longicorn beetles. The chromosome number ranged from 19 to 36, with a mode of 20 (diploid). The growth curve was determined at the 100th passage, and the population doubling time was calculated to be 3.79 d. Isozyme analysis of malic enzyme, phosphoglucose isomerase, and phosphoglucomutase revealed that PC-1 cells were enzymatically distinct from coleopteran XP-1, AnCu-35, dipteran AeAl-2, and lepidopteran GaMe-LF1 cell lines.
