Properties of Rice (Oryza sativaL.) Faecal Protein Particles: Light and Electron Microscopic Observations

• Published in: Journal of cereal science 1998-01, Vol.27 (1), p.83-93
• Main Authors: Barber, D.L., Lott, J.N.A., Yang, H.
• Format: Article
• Language: English
• Subjects: Biological and medical sciences; Feeding. Feeding behavior; Fundamental and applied biological sciences. Psychology; rice,Oryza sativaL., faecal protein particles, immunocytochemistry; Vertebrates: anatomy and physiology, studies on body, several organs or systems
• ISSN: 0733-5210; 1095-9963
• DOI: 10.1006/jcrs.1997.0149

The indigestible remains of rice (Oryza sativaL.) found in faeces of monogastric animals (faecal protein particles) appear as isolated, refractive spheres 1–2 μm in diameter. Still controversial, the prolamin-containing PB-I rice protein body has generally been proposed as the progenitor. We used polyclonal antibodies to purified fractions of rice prolamins and glutelins, to total rice protein, and to enzymatically- and chemically-derived waste particles of rice. Three classes of residual particles were examined immunocytochemically using Protein A-gold procedures to determine the polypeptide types present, and thus their possible origin. All particles contained antigenic determinants for all antibodies to the extracted rice polypeptides studied. There was also evidence of protein(s) peculiar to the residual bodies; the label on intact protein bodies showed a small amount of the unique protein(s), but label increased for all residual particles studied. In contrast, antigenic determinants for total rice protein were much reduced in residual particles. While measurement of profiles of intact PB-I and faecal protein particles shows no significant difference between their diameters, the immunocytochemical evidence linking faecal protein particles exclusively with PB-I rice protein bodies is less clear because intact PB-I and PB-II both show evidence of the unique protein also found in the residual particles.