Evaluation of horizontal gene transfer risk between the Mediterranean fruit fly Ceratitis capitata (Tephritidae) and its parasitoid Fopius ceratitivorus (Braconidae).

The transgenic strain of the Mediterranean fruit fly (medfly), Ceratitis capitata (Wied.) VIENNA 8 1260, developed from the classical genetic sexing strain VIENNA 8, has two molecular markers that exhibit red fluorescence in the body and green fluorescence in testicles and sperm. These traits offer a precise tool to discriminate between mass-reared sterile males and wild fertile males, and they could potentially increase the effectiveness of control programs for this pest. To assess the risk of horizontal transfer of the fluorescence transgenes in natural ecosystems, we used the VIENNA 8 1260 strain and the medfly parasitoid Fopius ceratitivorus. The fluorescence signal and the inheritance of the fluorescence gene markers were monitored for over 16 generations (about two years) in both species using fluorescence microscopy and a PCR-based assay. The PCR analysis was performed in four independent laboratories. Both fluorescence microscopy and PCR analysis indicated that no horizontal gene transfer of the DsRed transgene occurred during 16 generations of medfly parasitoid rearing under experimental conditions.

Levels of organochlorine pesticides in blood plasma from residents of malaria-endemic communities in Chiapas, Mexico.

Organochlorine (OC) pesticides have been extensively used for pest control in agriculture and against malaria vectors in the region of Soconusco, Chiapas, in southern Mexico. Our study aimed to identify whether the inhabitants of four Soconusco communities at different locations (i.e., altitudes) and with different history of use of OC pesticides, have been similarly exposed to residues of these pesticides. In particular, we analyzed the potential relationship between levels of OC pesticides in plasma and the age, gender, and residence of the study population (n = 60). We detected seven pesticides in total (γ-HCH, ß-HCH, heptachlor, p,p'-DDE, p,p'-DDT, ß-endosulfan, endrin aldehyde). Of these, p,p'-DDE and ß-endosulfan were the most frequently found (in 98% and 38% of the samples, respectively). The low-altitude (<20 m above sea level; masl) and mid-altitude (520 masl) locations had the highest levels of p,p'-DDE, with geometric means of 50.6 µg/L and 44.46 µg/L, respectively. The oldest subjects (>60 years) had the highest p,p'-DDE level (56.94 ± 57.81 µg/L) of all age groups, while men had higher p,p'-DDE (34.00 ± 46.76 µg/L) than women. Our results demonstrate that residents of the Soconusco region are exposed to p,p'-DDE because of high exposure to DDT in the past and current environmental exposure to this DDT-breakdown product.