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  • Resumo IPEN-doc 13668
    Immunological properties of sup(60)Co gamma rays irradiated bothropstoxin-I
    2008 - BAPTISTA, J.A.; VIEIRA, D.P.; GALISTEO JUNIOR, A.J.; CAPRONI, P.; CASARE, M.; ANDRADE JUNIOR, H.F.; SPENCER, P.J.; NASCIMENTO, N.
  • Artigo IPEN-doc 10737
    Immune response against bothropstoxin-I irradiated with sup(60) gamma rays
    2005 - BAPTISTA, J.A.; SPENCER, P.J.; HIGA, O.Z.; ANDRADE JUNIOR, H.F.; CESARE, M.S.; CAMPOS, L.A.; NASCIMENTO, N.
  • Artigo IPEN-doc 15156
    Physico-chemical characterization of gamma rays irradiated crotamine
    2009 - OLIVEIRA, KARINA C. de; SPENCER, PATRICK J.; NASCIMENTO, NANCI
    Ionizing radiation can change the molecular structure and affect the biological properties of biomolecules. It has been employed to attenuate animal toxins. Crotamine, a toxin from Crotalus durissus terrificus (Cdt), is a highly basic polypeptide (pI - 10.3), with myotoxic activity and molecular weight of 4882 Da. It is composed of 42 amino acids residues and reticulated by three disulfide bonds. This study aimed the characterization of irradiated crotamine using Circular Dichroism (CD), Fluorescence Spectroscopy and Differential Scanning Calorimetry (DSC) techniques. We used size exclusion and ion-exchange chromatography to purify it from Cdt crude venom. The pure crotamine was irradiated with 2.0 kGy from a 60Co source. Native and irradiated crotamine were analyzed in a fluorescence spectrophotometer (Hitachi F-4500), under excitation wavelength at 275 nm and the emission was scanned from 300 to 500 nm. The analysis of fluorescence quenching showed that the irradiated form displayed a lower quantum yield when compared to the native form. CD spectra, obtained from a Jasco, J-180 spectropolarimeter, of native and irradiated crotamine solutions, showed a discrete change between the samples, from apparently ordered conformation to a random coil. Finally, the thermodynamics analysis, realized in a calorimeter METTLER TOLEDO, DSC 822e, showed that irradiation promoted changes in the calorimetric profile. Our results indicate that irradiation leads to progressive changes in the structure of the toxin, which could explain the decrease in myotoxic activity.
  • Artigo IPEN-doc 11621
    Study of gamma-radiation effects on crotamine and crotoxin
    2006 - CASARE, M.S.; SPENCER, P.; CAMPOS, L.A.; NASCIMENTO, N.
    Crotoxin is a 23 kDa neurotoxin from Crotalus durissus terrificus and is composed of a 9 kDa acidic subunit (crotapotin) and a 14 kDa basic subunit (phospholipase A2). Crotamine is 4882 Da, basic polypeptide with myotoxic activity. These toxins, when submitted to gamma-rays, in aqueous solution, present structural modifications, preserving their immunogenic properties. In the present work, we investigated some structural modifications on both crotoxin and crotamine after gamma-radiation using various doses, in the presence or not of "scavenger" substances. Our results indicate that irradiation leads to progressive changes in the structure of the toxin, which could explain the lower toxicity observed.
  • Artigo IPEN-doc 14173
    Immunological properties of sup(60)Co gamma-rays irradiated bothropstoxin-I
    2009 - BAPTISTA, J.A.; VIEIRA, D.P.; GALISTEO JUNIOR, A.J.; CAPRONI, P.; CASARE, M.; ANDRADE JUNIOR, H.F. de; SPENCER, P.J.; NASCIMENTO, N.