Can the Genetic Origin Affect Rabbit Seminal Plasma Protein Profile along the Year?

The study was designed to evaluate the influence of genetic origin on rabbit seminal plasma protein profile variation along the year. Seminal plasma of rabbits from line A (maternal line) and R (paternal line) collected during a natural year was subjected to polyacrylamide gel electrophoresis (SDS‐PAGE). The electrophoretic profile of rabbit seminal plasma resulted in multiple protein bands of different intensity ranging from 9 to 240 kDa. Results showed that seven protein bands were significantly different between genetic lines, and among these, three protein bands were significantly different between seasons. The differentially expressed proteins were identified by MALDI‐TOF/TOF or LC‐MS/MS analysis and were the following ones: FAM115E‐like (220, 113 and 59 kDa), ectonucleoside triphosphate diphosphohydrolase 3 isoform X2 (72 kDa), annexin A5 (32 kDa), lipocalin allergen Ory c 4 precursor (19 kDa), and haemoglobin subunit zetalike (13 kDa) between genetic lines and FAM115E‐like (113 kDa), haemoglobin subunit zetalike (13 kDa) and β‐nerve growth factor (12 kDa) between seasons. These results indicate that proteins from rabbit seminal plasma are under both seasonal control and genetic control. Furthermore, the differential presence of these proteins could be one of the causes explaining the differences observed in fertility and seminal parameters between these two lines in earlier studies.     

Anchoring tick salivary anti-complement proteins IRAC I and IRAC II to membrane increases their immunogenicity

Tick salivary proteins are promising targets for the development of anti-tick vaccines. Recently, we described two paralogous anti-complement proteins, called Ixodes ricinus anti-complement (IRAC) proteins I and II, that are co-expressed in tick I. ricinus salivary glands. However, our previous attempts to immunize rabbits against IRAC via infection with recombinant Bovine herpesvirus 4 (BoHV-4) vectors invariably failed although both recombinants expressed high levels of functional IRAC proteins in vitro. As IRAC are soluble monovalent antigens, one of the possible explanations is that monovalent ligation of the B-cell receptor induces receptor activation but fails to promote antigen presentation, a phenomenon that is thought to induce a state of B-cell tolerance. In the present study, we tried to increase IRAC immunogenicity by expressing them as oligovalent antigens. To this end, IRAC were fused to membrane anchors and BoHV-4 vectors expressing these recombinant forms were produced. The immunization potentials of recombinant viruses expressing either secreted or transmembrane IRAC proteins were then compared. While the former did not induce a detectable immune response against IRAC, the latter led to high titres of anti-IRAC antibodies that only marginally affected tick blood feeding. All together, the data presented in this study demonstrate that the immunogenicity of a soluble antigen can be greatly improved by anchoring it in membrane.     

Molecular mechanism of antioxidant synergism of tocotrienols and carotenoids in palm oil

During repeated deep-fat frying of potato slices at 163 degrees C in yellow or red palm olein of comparable fatty acid profiles, the oxidative stability (peroxide value and anisidine value) of the palm oleins was similar, and in yellow palm olein, the rate of antioxidant depletion decreased in the order gamma-T3 > alpha-T3 > delta-T3 (T3, tocotrienol). In red palm olein, which had a total tocopherol/tocotrienol content of 1260 vs 940 ppm in yellow palm olein and a corresponding longer induction period in the Rancimat stability test at 120 degrees C, only depletion of gamma-T3 was significant among the phenols during frying and slower as compared to that in yellow palm olein. The carotenes in the red palm olein were depleted linearly with the number of fryings, apparently yielding an overall protection of the phenols. In antioxidant-depleted palm olein and in phospholipid liposomes with added increasing concentrations of phenols, gamma-T3 was found to be a better antioxidant than alpha-T3. alpha-T3 and alpha-T (T, tocopherol) had a similar antioxidant effect in antioxidant-depleted palm olein in the Rancimat stability test, while in the liposomes the ordering as determined by induction period for the formation of conjugated dienes was gamma-T3 > alpha-T3 > alpha-T. The addition of 100-1000 ppm beta-carotene to antioxidant-depleted palm olein or liposomes (lycopene also tested) did not provide any protection against oxidation. In the liposomes, synergistic interactions were observed between beta-carotene or lycopene and alpha-T, alpha-T3, or gamma-T3 for carotene/phenol ratios of 1:10 and 1:2 but not for 1:1. In chloroform, carotenes were regenerated by tocopherols/tocotrienols from carotene radicals generated by laser flash photolysis as shown by transient absorption spectroscopy, suggesting that carotenes rather than phenols are the primary substrate for lipid-derived radicals in red palm olein, in effect depleting carotenes prior to phenols during frying. Regeneration of carotenes by the phenols also explains the synergism in liposomes. In the laser flash photolysis experiments, gamma-T3 was also found to be faster in regenerating carotenes than alpha-T3 and alpha-T.