title: The expression of immune-related genes during the ontogenesis of scallop Chlamys farreri and their response to bacterial challenge.
abstract: In the present study, the expression of some immune-related genes was examined as indicator to understand the development of immune defense system during the ontogenesis of scallop Chlamys farreri. The mRNA transcripts of pattern-recognition receptors (PRRs) including CfPGRP-S1, CfLGBP, CfLec-1 and CfLec-3 were observed at a low level or even undetected at early developmental stages from eggs to blastula, and then began to increase overwhelmingly in trochophore. For the genes of immune effector including CfLYZ, CfLBP/BPI, CfSOD and CfCAT, their mRNA transcripts were higher expressed in embryos, and increased significantly in D-hinged or early veliger larvae. The whole-mount immunofluorescence assay revealed two immunoreactive spots of CfPGRP-S1 were first observed in the mid-ventral region of prototroch in trochophore, and the immunopositive fluorescence of CfLGBP, CfLec-1 and CfLec-3 appeared at the same spots in early D-hinged larvae. Most of the PRRs were located in velum, mouth, esophagus and stomach region in early and mid-veliger larvae, and especially the strong immunopositive fluorescence of CfLec-3 was observed in velum. The immunoreactive areas of CfLYZ, CfLBP/BPI, CfSOD and CfCAT were observed in trochophore and early D-hinged larvae. After D-hinged larvae, they distributed in different tissues from the edge of velum, mouth, esophagus to the region around digestive gland. After bacterial challenge, the mRNA expression of CfLGBP, CfLec-1 and CfLec-3 did not change significantly in trochophore, while a down-regulation of CfPGRP-S1 was observed at 6 h (P < 0.05). The expression of CfPGRP-S1 and CfLGBP decreased or increased inversely in D-hinged and late veliger larvae respectively, whereas CfLec-1 and CfLec-3 increased significantly during 6-24 h after bacterial challenge in the two stages (P < 0.05). In contrast, the expressions of immune effectors in trochophore and late veliger larvae were significant up-regulated at 6 h, 12 h or 24 h after bacterial challenge (P < 0.05). However, in late D-hinged larvae, CfLYZ and CfSOD expressions were significantly down-regulated at 6 h, while CfLBP/BPI expression was up-regulated at 6 h and 24 h post challenge (P < 0.05). These results indicated that the immune defense system of scallop might appear firstly in the mid-ventral region of prototroch in trochophore, and developed maturely after late D-hinged larvae. The developing immune system in the D-hinged and late veliger larvae could respond to the immune stimulation in different manner.
authors: Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, 7 Nanhai Rd., Qingdao, Shandong 266071, China.
authors: Feng
authors: F
authors: Yue
authors: Xiaowei
authors: X
authors: Shi
authors: Zhi
authors: Z
authors: Zhou
authors: Lingling
authors: L
authors: Wang
authors: Mengqiang
authors: M
authors: Wang
authors: Jialong
authors: J
authors: Yang
authors: Limei
authors: L
authors: Qiu
authors: Linsheng
authors: L
authors: Song
mesh_terms: D000818:Animals; D002352:Carrier Proteins / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D005260:Female; D005455:Fluorescent Antibody Technique; D018507:Gene Expression Regulation, Developmental; D007113:Immunity, Innate; D007814:Larva / Q000254:growth & development / Q000276:immunology / Q000382:microbiology / Q000502:physiology; D037102:Lectins / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D008070:Lipopolysaccharides / Q000276:immunology; D008297:Male; D009928:Organ Specificity; D049897:Pectinidae / Q000254:growth & development / Q000276:immunology* / Q000382:microbiology / Q000502:physiology; D012333:RNA, Messenger / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction; D051192:Receptors, Pattern Recognition / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D011994:Recombinant Proteins / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D014733:Vibrio / Q000276:immunology
chemical_list: D002352:Carrier Proteins; D037102:Lectins; D008070:Lipopolysaccharides; D012333:RNA, Messenger; D051192:Receptors, Pattern Recognition; D011994:Recombinant Proteins; C118897:peptidoglycan recognition protein