Yoshiro Nakajima

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A genome-wide analysis of innate immunity-related genes and gene families was conducted using the silkworm, Bombyx mori. We identified orthologs for a large number of genes involved in insect immunity that have been reported from Drosophila melanogaster (Diptera), Anopheles gambiae (Diptera), Apis mellifera (Hymenoptera) and Tribolium castaneum(More)
Defensins are a major group of antimicrobial peptides and are found widely in vertebrates, invertebrates and plants. Invertebrate defensins have been identified from insects, scorpions, mussels and ticks. In this study, chemically synthesized tick defensin was used to further investigate the activity spectrum and mode of action of natural tick defensin.(More)
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(More)
We previously purified and determined the partial amino acid sequence of a 4 kDa peptide having high homology with scorpion defensin from the hemolymph of adult fed female soft ticks, Ornithodoros moubata. In this study, the full length sequences of two defensin isoforms were obtained. Deduced amino acid sequences reveal a precursor protein of 73 amino acid(More)
Two defensin genes A and B were previously demonstrated to be up-regulated by blood feeding in the soft tick, Ornithodoros moubata [Nakajima et al. (2001) Two isoforms of a member of the arthropod defensin family from the soft tick, Ornithodoros moubata (Acari: Argasidae). Insect Biochem Mol Biol 31: 747-751]. In this study, two defensin isoforms C and D(More)
Actin genes are found in all living organisms and highly conserved in various animals as shown by numerous studies on actin gene expression and function. Because of this ubiquitous nature of actin, it is often used as an internal control in gene expression studies. To clarify the suitability of actin gene as an internal control in soft ticks, isolation and(More)
In the silkworm, Bombyx mori, antimicrobial peptide (AMP) genes are upregulated in the larval fat body by injection of bacteria and peptidoglycans (PGNs). The DAP-type PGN from Escherichia coli and Bacillus subtilis exhibited stronger elicitor activity for expression of AMP genes in B. mori than Lys-type PGN from Staphylococcus aureus, suggesting that(More)
Retinoid X receptors (RXR) exist broadly from invertebrates to vertebrates, and play essential roles in physiological processes of these organisms. In arthropods, RXRs form a complex with the ecdysteroid receptor (EcR) and ecdysteroids to mediate the regulation of ecdysis and reproduction. Compared to EcR, RXR and its homologue ultraspiracle (USP) are much(More)
Animals are constantly threatened by pathogenic microorganisms and have developed cellular and humoral immune responses to combat these infections. Invertebrates possess only an innate non-specific immune response. Antimicrobial substances are major components of innate immunity not only in invertebrates but also in vertebrates. Despite the importance of(More)