Congruence between starch gel and polyacrylamide gel electrophoresis in detecting allozyme variation in pulmonate land slugs

The predominantly selfing slug species Arion (Carinarion) fasciatus, A. (C.) silvaticus and A. (C.) circumscriptus are native in Europe and have been introduced into North America, where each species consists of a single, homozygous multilocus genotype (strain), as defined by starch gel electrophoresis (SGE) of allozymes. In Europe, the “one strain per species” hypothesis does not hold since polyacrylamide gel electrophoresis (PAGE) of allozymes uncovered 46 strains divided over the three species. However, electrophoretic techniques may differ in their ability to detect allozyme variation. Therefore, several Carinarion populations from both continents were screened by applying the two techniques simultaneously on the same individual slugs and enzyme loci. SGE and PAGE yielded exactly the same results, so that the different degree of variation in North American and European populations cannot be attributed to differences in resolving power between SGE and PAGE. We found four A. (C.) silvaticus strains in North America indicating that in this region the “one strain per species” hypothesis also cannot be maintained. Hence, the discrepancies between previous electrophoretic studies on Carinarion are most likely due to sampling artefacts and possible founder effects.

Liver-like biosensor: immobilized CYP3A4 sensors as tools for ligand binding and enzyme activity measurements

Cytochromes P450 constitute a super-family of enzymes involved in the metabolism of Xenobiotics, where human cytochrome P450 3A4 is the most abundant of all P450s, accounting for about 50% of all human liver cytochromes. This membrane anchored protein is responsible for the metabolization of a wide array of environmental drugs and intoxicants, mainly due to its haem domain properties, and active site cavity volume. These properties make this protein an excellent subject for biosensor application, although CYO3A4 enzyme is also famous for its instability. Enzyme inactivation at room temperature is a normal conversion process that this enzyme undergoes, that may hamper any biosensing approach.