title: Antibacterial hemoglobin fragments from the midgut of the soft tick, Ornithodoros moubata (Acari: Argasidae).
abstract: Midgut contents of Ornithodoros moubata showed strong antibacterial activity against Staphylococcus aureus. A combination of reversed-phase chromatography and mass spectrometric analysis was used to isolate two antibacterial peptides from the tick midgut lumen. Partial amino acid sequences by Edman degradation of these two peptides showed they are identical with the 1-11 and 3-19 portions of rabbit a hemoglobin. Host rabbit a hemoglobin appears to be cleaved between Met32 and Phe33 to produce these two antibacterial peptides. Isolation of a host bovine hemoglobin fragment with antimicrobial activity has been demonstrated in the Ixodid tick, Boophilus microplus (Fogaca et al. 1999). Similar immune mechanisms in the two major families of ticks, Ixodidae and Argasidae, appear to use the hemoglobin of the host as an antimicrobial agent in midgut defense.
authors.affiliation: Institute of Agriculture and Forestry, University of Tsukuba, Tsukuba, Ibaraki, 305-8572, Japan.
authors.forename: Yoshiro
authors.initials: Y
authors.lastname: Nakajima
authors.forename: Kazumasa
authors.initials: K
authors.lastname: Ogihara
authors.forename: Demar
authors.initials: D
authors.lastname: Taylor
authors.forename: Minoru
authors.initials: M
authors.lastname: Yamakawa
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000890:Anti-Infective Agents / Q000737:chemistry / Q000302:isolation & purification*; D004064:Digestive System / Q000737:chemistry*; D006454:Hemoglobins / Q000737:chemistry*; D013058:Mass Spectrometry; D008969:Molecular Sequence Data; D026861:Ornithodoros / Q000382:microbiology*; D010446:Peptide Fragments / Q000737:chemistry* / Q000302:isolation & purification; D016415:Sequence Alignment; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
chemical_list: D000890:Anti-Infective Agents; D006454:Hemoglobins; D010446:Peptide Fragments