title: Existence of prophenoloxidase in wing discs: a source of plasma prophenoloxidase in the silkworm, Bombyx mori.
abstract: In insects, hemocytes are considered as the only source of plasma prophenoloxidase (PPO). PPO also exists in the hemocytes of the hematopoietic organ that is connected to the wing disc of Bombyx mori. It is unknown whether there are other cells or tissues that can produce PPO and release it into the hemolymph besides circulating hemocytes. In this study, we use the silkworm as a model to explore this possibility. Through tissue staining and biochemical assays, we found that wing discs contain PPO that can be released into the culture medium in vitro. An in situ assay showed that some cells in the cavity of wing discs have PPO1 and PPO2 mRNA. We conclude that the hematopoietic organ may wrongly release hemocytes into wing discs since they are connected through many tubes as repost in previous paper. In wing discs, the infiltrating hemocytes produce and release PPO probably through cell lysis and the PPO is later transported into hemolymph. Therefore, this might be another source of plasma PPO in the silkworm: some infiltrated hemocytes sourced from the hematopoietic organ release PPO via wing discs.
authors: Key Laboratory of Insect Developmental and Evolutionary Biology, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, People's Republic of China.
authors: Yupu
authors: Y
authors: Diao
authors: Anrui
authors: A
authors: Lu
authors: Bing
authors: B
authors: Yang
authors: Wenli
authors: W
authors: Hu
authors: Qing
authors: Q
authors: Peng
authors: Qing-Zhi
authors: QZ
authors: Ling
authors: Brenda T
authors: BT
authors: Beerntsen
authors: Kenneth
authors: K
authors: Söderhäll
authors: Erjun
authors: E
authors: Ling
mesh_terms: D000818:Animals; D012831:Bombyx / Q000201:enzymology*; D004156:Catechol Oxidase / Q000378:metabolism*; D004792:Enzyme Precursors / Q000378:metabolism*; D006434:Hemocytes / Q000201:enzymology; D006458:Hemolymph / Q000201:enzymology*; D060227:Imaginal Discs / Q000201:enzymology*; D019476:Insect Proteins / Q000378:metabolism*; D007814:Larva / Q000201:enzymology
chemical_list: D004792:Enzyme Precursors; D019476:Insect Proteins; C038451:pro-phenoloxidase; D004156:Catechol Oxidase