title: Effects of silkworm paralytic peptide on in vitro hematopoiesis and plasmatocyte spreading.
abstract: Bombyx mori paralytic peptide (BmPP), a multifunctional cytokine-like molecule, is expressed in the hematopoietic organ-wing imaginal disc complex, suggesting that BmPP is involved in both immune response and the hematopoietic process. We studied the effects of BmPP on plasmatocytes and hematopoietic organs of the silkworm. BmPP (1 microM) stimulated spreading of circulating plasmatocytes, but the percentage of spread plasmatocytes was only 20%. Over 10 nM of BmPP, however, elicited prominent spreading in 70% of young plasmatocytes discharged from cultured hematopoietic organs. Cells in hematopoietic organs that were enzymatically dispersed did not spread even after adding 100 nM of BmPP, indicating that plasmatocytes acquired BmPP-sensitivity immediately after discharge. When cultured in a medium containing larval plasma, hematopoietic organs grew markedly and discharged a large number of hemocytes, over 95% of which were morphologically plasmatocytes. The hemocyte discharge was blocked in the medium containing BmPP dose-dependently, although hematopoietic organ growth was not suppressed. These results suggest that BmPP plays important roles both in hematopoietic regulation and in the hemocyte immune reaction of the silkworm.
authors.affiliation: National Institute of Agrobiological Sciences, Ibaraki, Japan.
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Nakahara
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Kanamori
authors.forename: Makoto
authors.initials: M
authors.lastname: Kiuchi
authors.forename: Manabu
authors.initials: M
authors.lastname: Kamimura
mesh_terms: D000818:Animals; D030801:Animals, Genetically Modified; D015153:Blotting, Western; D012831:Bombyx / Q000187:drug effects / Q000502:physiology*; D002448:Cell Adhesion / Q000187:drug effects / Q000502:physiology; D002449:Cell Aggregation / Q000187:drug effects / Q000502:physiology; D002452:Cell Count; D004305:Dose-Response Relationship, Drug; D006098:Granulocytes / Q000166:cytology / Q000187:drug effects; D049452:Green Fluorescent Proteins; D006410:Hematopoiesis / Q000187:drug effects* / Q000502:physiology; D006434:Hemocytes / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D007814:Larva / Q000187:drug effects / Q000502:physiology; D008164:Luminescent Proteins / Q000737:chemistry / Q000235:genetics; D008856:Microscopy, Fluorescence; D008857:Microscopy, Interference / Q000379:methods; D009479:Neuropeptides / Q000494:pharmacology* / Q000502:physiology
chemical_list: D008164:Luminescent Proteins; D009479:Neuropeptides; C121924:paralytic peptide, insect; D049452:Green Fluorescent Proteins