One hundred 6-to 12-month-old Nelore calves were allotted into control group (G1; 50 healthy calves) and photosensitization group (G2; n= 50). Blood samples were collected 12 to 24 hours after the onset of dermatitis (M1), and 15 to 30 days after that (M2), at time of resolution of clinical signs. Serum protein electrophoresis was performed by means of sodium dodecyl sulphate-polyacrylamide gel electrophoresis. Eighteen serum proteins with molecular weights ranging from 16,000 to 189,000 daltons (Da) were identified in all calves. In M1 and M2 serum concentrations of proteins with molecular weights of 115,000Da (ceruloplasmin), 61,000Da (α 1 -antitrypsin), 45,000Da (haptoglobin), and 40,000Da (acid glycoprotein) were significantly increased in calves. In conclusion, measurement of serum acute phase protein concentrations may be useful in monitoring the progression of bovine hepatogenous photosensitization, including guide probable alteration on therapeutic procedures.Keywords: calf, hepatogenous photosensitization, acute phase protein de PM 115.000Da (ceruloplasmina), 45.000Da (haptoglobina) RESUMO Foram examinados 100 bezerros da raça Nelore com 6 a 12 meses de idade, distribuídos em: grupo controle (G1; 50 bezerros sadios) e grupo fotossensibilização (G2; n= 50). As amostras de sangue foram coletadas 12 a 24 horas após o início da dermatite (M1) e 15 a 30 dias após (M2), época da cura das lesões cutâneas. O proteinograma sérico foi obtido por eletroforese em gel de acrilamida. Em todos os bezerros foram identificadas 18 proteínas com pesos moleculares (PM) entre 16.000 a 189.000 dáltons (Da). Em M1 e M2, as concentrações séricas das proteínas

The ability of synthetic arginine-glycine-aspartic acid (RGD)-containing peptides to induce intracellular calcium transients similar to those observed at fertilization by spermatozoa in the bovine has been reported (Campbell et al., 2000: Biol Reprod 62:1702-1709; Sessions et al., 2006. Mol Reprod Dev). These results also indicated the ability of synthetic RGD-containing peptides to induce activation and subsequent parthenogenetic development to the blastocyst stage, although, at numbers lower than observed with control in vitro fertilization (IVF). Evidence has been provided indicating the important effect of surrounding regions on the biological activity of the RGD sequence (Zhu and Evans, 2002; Sessions et al., 2006). The current experiments were designed to use natural RGD-containing sequences (disintegrins) to understand their effects. A total of three RGD-containing snake venom peptides (Kistrin (K), Elegantin (Ele), and Echistatin (Ech)) and one nonRGD-containing venom (Erabutoxin B (EB; control) were used at three concentrations (0.1, 1, and 10 micro g /ml) to induce parthenogenetic development to the blastocyst stage and in conjunction (1.0, 5.0, and 10 micro g/ml) with spermatozoa to evaluate competitive inhibition of fertilization and subsequent development. A (P < 0.01) higher number of bovine oocytes developed to the blastocyst stage after incubation with K, Ele and Ech at 1.0 micro g/ml, and was not different (P > 0.01) from IVF control. Fertilization was significantly reduced (P < 0.01) at all concentrations of K, Ele and Ech as compared to IVF control. No reduction (P > 0.05) was observed in EB (nonRGD) treated oocytes. These results support the involvement of a disintegrin-integrin interaction at fertilization in the bovine resulting in activation and subsequent development.