title: Histopathological effects and immunolocalization of periplocoside NW from Periploca sepium Bunge on the midgut epithelium of Mythimna separata Walker larvae.
abstract: Periplocoside NW (PSNW) with pregnane glycoside skeleton is a novel insecticidal compound isolated from the root bark of Periploca sepium Bunge. This compound has a potent stomach poisoning activity against several insect pests. In this study, we observed the intoxication symptoms, investigated the histopathological effects and carried out immuno-electron microscopic localization of PSNW on the midgut epithelium of oriental armyworm Mythimna separata Walker larvae for better understanding its action mechanism against insects. Ultrastructural observations showed that cell damages caused by PSNW in the midgut of M. separata larvae are related to the degeneration of brush border microvilli. The dissolution of cytoskeletal structures in the interior and on the surface of microvilli was responsible for the decrease in size and eventual disappearance of microvilli when bubbles of cytoplasmic substances protrude into the midgut lumen of M. separata, thus resulting in cell death. The immuno-electron microscopic localization research showed that gold particle appeared on the microvilli layer of the midgut of M. separate larvae firstly. The density of gold particle gradually added with the time, and finally microvilli layer was destructed severely. Meantime, the gold particles were also presented to the intracellular organelle membrane and the organelles also were destructed. Therefore, we proposed that this membrane system on insect midgut epithelium cells is the initial acting site of PSNW against insects.
authors.affiliation: Institute of Pesticide Science, Northwest Agriculture and Forestry University, Yangling 712100, PR China.
authors.forename: Mingxing
authors.initials: M
authors.lastname: Feng
authors.affiliation: Institute of Pesticide Science, Northwest Agriculture and Forestry University, Yangling 712100, PR China.
authors.forename: Baojun
authors.initials: B
authors.lastname: Shi
authors.affiliation: Institute of Pesticide Science, Northwest Agriculture and Forestry University, Yangling 712100, PR China.
authors.forename: Yanchao
authors.initials: Y
authors.lastname: Zhao
authors.affiliation: Institute of Pesticide Science, Northwest Agriculture and Forestry University, Yangling 712100, PR China. Electronic address: huzhaonong@nwsuaf.edu.cn.
authors.forename: Zhaonong
authors.initials: Z
authors.lastname: Hu
authors.affiliation: Institute of Pesticide Science, Northwest Agriculture and Forestry University, Yangling 712100, PR China.
authors.forename: Wenjun
authors.initials: W
authors.lastname: Wu
mesh_terms: D000818:Animals; D004064:Digestive System / Q000737:chemistry / Q000187:drug effects / Q000648:ultrastructure; D004848:Epithelium / Q000737:chemistry / Q000187:drug effects / Q000648:ultrastructure; D006027:Glycosides / Q000633:toxicity*; D006653:Histology; D007306:Insecticides / Q000633:toxicity*; D007814:Larva / Q000737:chemistry / Q000187:drug effects / Q000648:ultrastructure; D016253:Microscopy, Immunoelectron; D008871:Microvilli / Q000737:chemistry / Q000187:drug effects / Q000648:ultrastructure; D009036:Moths / Q000737:chemistry / Q000187:drug effects* / Q000648:ultrastructure; D031109:Periploca / Q000737:chemistry*; D010936:Plant Extracts / Q000633:toxicity*; D011278:Pregnanes / Q000633:toxicity*
chemical_list: D006027:Glycosides; D007306:Insecticides; D010936:Plant Extracts; D011278:Pregnanes; C574437:pregnane glycoside
keywords: Botanical insecticide; Histopathological effects; Immunolocalization; Mythimna separata; Periploca sepium; Periplocoside NW