Semiquantitative analysis of genetically modified maize and soybean in food

The aim of this study was to analyze quantitatively the presence of genetically modified organism in food with different composition and degree of processing. Total DNA was extracted by Dellaporta's method and GMO analysis was performed using two consecutives PCR reactions with specie specific primers (IVR and LE), screening primers (35S) and transgen specific primers (CRY and EPSPS). The quantification within the sensitivity establish by the EU was possible only in some foods (ice-cream, flours, soybean isolates and concentrates, starch). Samples with high lipid content or subjected to intense thermal treatments (such as some snacks, mayonnaise, creamy soup) could not be amplified mainly due to the presence of PCR inhibitors. Therefore the method was adequate for identification of food as GM, within the limits establish by EU, only for some Argentinean commercial food products. These findings showed that the develop method was satisfactory only for simple food that were not subject to intense thermal treatments and that do not have high lipid content and that the main limitation of the method is DNA purity.

Sunflower storage proteins are transported in dense vesicles that contain proteins homologous to the pumpkin vacuolar sorting receptor PV 72

Storage proteins are transported to a special storage compartments in seeds by Golgi dependent or independent pathways depending on the plant species. The aim of this work was to study the sunflower storage protein transport pathway and identified component of the sorting machinery. Immature sunflower seeds were analyzed by subcellular fractionation (using percoll and sucrose gradients) and electron microscopy. The vesicles isolated with percoll, have precursors of 11S globulins, á-TIP, ã-TIP, BiP, and two proteins that have homology to the pumpkin vacuolar sorting receptor PV72. Sucrose isolated vesicles have the same composition than percoll ones, except for the lack of BiP and the presence of only one protein that has reactivity with pea VSR BP80. Electronic micrographies of developing seeds show that the formation of electron dense aggregates starts in the endoplasmic reticulum, and that these aggregates are very abundant in the trans-Golgi apparatus, where release of dense vesicles happens. These vesicles contain a homolog of PV72 in their membranes. Storage proteins are also detected in multivesicular bodies whose membranes have reactivity with PV72 serum. All these results indicated that sunflower storage proteins are transported to protein storage vacuoles by a Golgi dependent pathway in a process in which homologous of PV72 are involved.

Expression of the antibody 14D9 in Nicotiana tabacum hairy roots

Nicotiana tabacum hairy roots that express the antibody 14D9 were established. The 14D9 antibody yield obtained after 20 days of culture was 5.95 μg 14D9ml-1. The addition of the reticulum endoplasmic retention sequence KDEL demonstrated a positive effect over the intracellular 14D9 amounts with a yield increase up to 20.82 µg ml-1. DMSO increased the antibody amount in the biomass from 20.00 to 64.03 µg ml-1 while PVP (at 1.5 gl-1) and gelatine (at 5.0 gl-1) increased total 14D9 amounts in the culture medium to 25 µg and 14 µg respectively.