Intersexuality and Endocrine Disruption in the Amphipod Echinogammarus marinus – From Genes to Physiology
type: CreativeWork
description: The intertidal amphipod (Echinogammarus marinus LEACH) exhibits several forms of intersexuality (intersex males and intersex females) and has been considered an ideal model to study reproductive endocrine disruption in Crustacea. This study aimed to investigate both the physiology and gene expression in intersex E. marinus with the objective of better understanding their reproductive biology and aid the development of biomarkers of de-masculinisation in Crustacea. E. marinus populations from three Scottish (Thurso, Inverkeithing and Loch Fleet) and two English sites (Portsmouth Harbour and Langstone Harbour) were assessed for intersexuality prevalence, sperm counts or microsporidian infection rate. Increased incidence of intersexes and reduced sperm counts were revealed in amphipods from industrial impacted sites. The microsporidian species infecting E. marinus were identified for the first time, and Dictyocoela duebenum and Dictyocoela berillonum were found to be dominant in Inverkeithing and Portsmouth Harbour E. marinus populations, respectively. Microsporidian has been reported as a potential factor inducing intersexes in amphipods, and this study also revealed a strong association between microsporidian infection and intersexes in E. marinus. A cross-species cDNA microarray was used to characterise the gene expressions of three male phenotypes (normal males, internal and external intersex males), and PCA analysis clearly differentiates the three groups into three separate patches. The de novo transcriptome sequencing was carried out on E. marinus gonadal tissue, by 9 employing Roche 454 pyrosequencing producing one of the largest cDNA libraries for a crustacean species. A total of 12,645 gonadal contigs were assembled from 213,212 sequencing reads, and 1206, 1745 and 782 contigs were found to be male-, female- and intersex-specific genes, respectively. This study revealed that the majority of internal intersex males were without microsporidian infection, indica…
abstract: The intertidal amphipod (Echinogammarus marinus LEACH) exhibits several forms of intersexuality (intersex males and intersex females) and has been considered an ideal model to study reproductive endocrine disruption in Crustacea. This study aimed to investigate both the physiology and gene expression in intersex E. marinus with the objective of better understanding their reproductive biology and aid the development of biomarkers of de-masculinisation in Crustacea. E. marinus populations from three Scottish (Thurso, Inverkeithing and Loch Fleet) and two English sites (Portsmouth Harbour and Langstone Harbour) were assessed for intersexuality prevalence, sperm counts or microsporidian infection rate. Increased incidence of intersexes and reduced sperm counts were revealed in amphipods from industrial impacted sites. The microsporidian species infecting E. marinus were identified for the first time, and Dictyocoela duebenum and Dictyocoela berillonum were found to be dominant in Inverkeithing and Portsmouth Harbour E. marinus populations, respectively. Microsporidian has been reported as a potential factor inducing intersexes in amphipods, and this study also revealed a strong association between microsporidian infection and intersexes in E. marinus. A cross-species cDNA microarray was used to characterise the gene expressions of three male phenotypes (normal males, internal and external intersex males), and PCA analysis clearly differentiates the three groups into three separate patches. The de novo transcriptome sequencing was carried out on E. marinus gonadal tissue, by 9 employing Roche 454 pyrosequencing producing one of the largest cDNA libraries for a crustacean species. A total of 12,645 gonadal contigs were assembled from 213,212 sequencing reads, and 1206, 1745 and 782 contigs were found to be male-, female- and intersex-specific genes, respectively. This study revealed that the majority of internal intersex males were without microsporidian infection, indica…
author: Yang, Gongda
language: eng
date published: 2013-1-17
date modified: 2026-07-24T05:12:04Z
provider: University of the Highlands and Islands
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: University of Edinburgh