Transgene and mitochondrial DNA are indicators of efficient composting of transgenic pig carcasses.

Composting is an environmentally sound method for the disposal of on-farm livestock mortalities that generates material suitable for use as fertilizer; however, this method is not generally permitted for disposal of transgenic livestock mortalities during the research and development phase. This study has explored the application of the polymerase chain reaction (PCR) as a method for assessing the persistence of transgene and mitochondrial DNA markers during the composting of euthanized transgenic pig. There was at least a 10(7) fold reduction of genetic material to a level that not either transgene or mitochondrion markers were detectable. At the end of the composting period, only bone fragments that were completely demineralised and chalky were detected. Chemically the compost was similar to that from pig litter and poultry mortalities, except the copper content was lower. Based on these data, composting appears to be an appropriate method for the disposal of transgenic animals.

Inducible expression of green fluorescent protein in porcine tracheal epithelial cells by the bovine tracheal antimicrobial peptide promoter.

Tracheal antimicrobial peptides (TAP) are expressed primarily in respiratory epithelial cells of cattle. The TAP expression is inducible upon challenge with bacteria and bacterial lipopolysaccharide (LPS). In pigs, a promoter that can be activated by bacterial infection has yet to be identified. The objective of this study was to use green fluorescent protein (GFP) as a reporter gene to determine the function and inducibility of the bovine TAP promoter in porcine primary tracheal epithelial cells. Thus, evaluating the feasibility of using this promoter to direct transgene expression in porcine cells. The percentage of GFP expressing cells increased in response to LPS challenge in both a dose-dependent and time-dependent manner (p < 0.05). Moreover, when the intensity of the GFP fluorescence was measured, it was observed that the percentage of cells that have a high intensity of GFP fluorescence, also increased gradually as LPS dose increased, the difference between the unchallenged (control) and challenged group become statistically significant at the concentration of 100 ng/mL after 36 h LPS challenge (p < 0.05). The level of induced-expression driven by the TAP promoter was 67.8 +/-12.2% that of the cytomegalovirus (CMV) promoter. The intensity of GFP fluorescence by the TAP promoter was 39.8 +/- 7.6% when compared to the expression driven by the CMV promoter. These data suggest the TAP promoter functions at a lower, but comparable, level to the strong CMV promoter. Our data demonstrated that the bovine TAP promoter was functional in porcine primary tracheal epithelial cells. The ability of the TAP promoter to control gene expression in an inducible manner in the porcine respiratory tract presents an important application potential in transgenic animal studies.