title: Molecular characterization of goose- and chicken-type lysozymes in emu (Dromaius novaehollandiae): evidence for extremely low lysozyme levels in emu egg white.
abstract: Lysozyme (LZ), a bacteriolytic enzyme, is found in the egg white of many avian eggs and plays an important role in host defense; however, LZ activity in emu (Dromaius novaehollandiae) egg white is exceptionally undetectable. We cloned and characterized emu goose-type LZ (LZG) and chicken-type LZ (LZC) genes. RT-PCR analysis revealed very low LZG gene expression levels and absence of LZC gene expression in the emu oviduct. Sequencing of full-length LZG and LZC cDNAs indicated that their amino acid sequences show high similarities to ostrich LZG and LZC, respectively, with conserved catalytic residues for enzymatic activities. Whereas recombinant emu LZG prepared using Pichia pastoris exhibited similar enzyme activity as ostrich LZG, recombinant emu LZC exhibited significantly higher lytic activity than chicken LZC. We concluded that emus have functional genes for both LZG and LZC like many other avians, and the LZG gene is expressed in oviduct probably as in other ratite, however, its expression levels in egg white were low to be detected.
authors: Department of Fermentation Science, Faculty of Applied Bio-Science, Tokyo University of Agriculture, 1-1-1 Sakuragaoka, Setagaya-ku, Tokyo 156-8502, Japan. maehashi@nodai.ac.jp
authors: Kenji
authors: K
authors: Maehashi
authors: Mami
authors: M
authors: Matano
authors: Tomohiro
authors: T
authors: Irisawa
authors: Masataka
authors: M
authors: Uchino
authors: Yutaka
authors: Y
authors: Kashiwagi
authors: Toshihiro
authors: T
authors: Watanabe
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002645:Chickens / Q000235:genetics; D020312:Dromaiidae / Q000235:genetics*; D004529:Egg White / Q000737:chemistry*; D005260:Female; D005777:Geese / Q000235:genetics; D009113:Muramidase / Q000235:genetics / Q000378:metabolism*; D010057:Oviducts / Q000378:metabolism; D010802:Phylogeny; D010843:Pichia / Q000235:genetics; D011994:Recombinant Proteins; D016415:Sequence Alignment; D020310:Struthioniformes / Q000235:genetics
chemical_list: D011994:Recombinant Proteins; D009113:Muramidase