Differential gene expression in normal and intersex Crustacea: New horizons for investigating impacts of pollution, parasitism and climate change.

Lead Research Organisation: University of Portsmouth
Department Name: School of Biological Sciences

Abstract

Intersexuality is the abnormal condition when an organism displays characteristics of being both male and female. The study of intersexuality in wildlife provides excellent means for studying comparative biology of abnormal conditions in reproductive determination and/or differentiation. Intersex in crustaceans can occur through genetic abberations, parasitism, disrupted environmental sex determination (ESD) and through chemical exposure. The genetic knowledge of crustacean groups is currently very limited making the assessment of mechanisms behind environmental sex determination (ESD); feminsing parasites; and pollution very limited in this ecologically important group: thus hot-topics in environmental sciences such as endocrine disruption and climate change are difficult to assess without a clear understanding of the biology of ecologically relevant species. Considerable information exists at the physiological, individual and population level impacts of temperature, photoperiod, and parasitism on the sex determination in amphipods. In addition, several studies have suggested sexual disruption might also be occuring in this group following exposure to environmental contaminents. Following on from a NERC 454 pilot study into gene expression in normal and intersex gonadal tissues, this project would utilise high-throughput sequencing technologies to complete a suite of archived biological tissues for specific gene expression in male and female amphipods and two intersex phenotypes (intersex males and females); increasing substantially the genetic knowledge for this and crustacean groups in general. Intra and inter specific differences between organs of males, females, intersex males and intersex females would be compared by digital transcriptmics. Following some evidence that suggests that male crustaceans maybe impacted by pollution in a way that effects their male hormones and cause demasculinisation (a more female-like appearance). Further studies would experimently induce de-masculinisation in an intertidal amphipod using three methods; firstly, physically dissecting the male (androgenic) glands; secondly, through infection with feminising parasites; and thirdly, through chemical exposure to some known endocrine disrupting chemicals. These experiments would be used to examine comparisons in the genes being up/down regulated following each experimental manipulation. Key genes would be selected and utilised to develop assays to assess whether demasculinisation is occuring in field collected specimens from clean and polluted sites. All genetic data acquired during these studies would be made publically available through a specially designed database entitled AmphiBASE.

Publications

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Lewis C (2012) Infertility in male aquatic invertebrates: a review. in Aquatic toxicology (Amsterdam, Netherlands)

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Fong PP (2014) The biological effects of antidepressants on the molluscs and crustaceans: a review. in Aquatic toxicology (Amsterdam, Netherlands)

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Short S (2014) Vitellogenin is not an appropriate biomarker of feminisation in a crustacean. in Aquatic toxicology (Amsterdam, Netherlands)

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Ford AT (2012) Intersexuality in Crustacea: an environmental issue? in Aquatic toxicology (Amsterdam, Netherlands)

 
Description We have developed a set of molecular tools to investigate the health of crustaceans. The initial objective was to design these tools with the view to determining whether pollution could alter the sex and reproductive development of crustaceans. In sequencing the entire set of genes for our model organism we have provided the scientific community with the ability to study crustaceans not previously possible due to the lack of molecular information. This dataset is now publicly available for anybody to use. We have more recently used this resource to measure the genes involved in behaviour following experiments exposing crustaceans to pharmaceutical pollutants such as antidepressants.

We have discovered several new species of parasites, one capable of altering the sex of their crustacean hosts and another capable of altering their behaviour. We have also measured gene expression in organisms with and without infection with these parasites. We have investigated the role of environmental sex determination in crustaceans linking field and laboratory experiments to enlighten us about the possible implications of climate change.
Exploitation Route International regulatory authorities concerned with monitoring the health of aquatic environments would be able to use our datasets and experimental research tools to determine whether ecologically important crustaceans are being impacted by pollutants.
Sectors Agriculture, Food and Drink,Chemicals,Environment,Pharmaceuticals and Medical Biotechnology

 
Description Developing biomarkers of sewage effluent exposure in freshwater amphipods (Gammarus)
Amount £37,000 (GBP)
Organisation ETH Zurich 
Sector Academic/University
Country Switzerland
Start 02/2017 
End 02/2020
 
Description EU Interreg Program
Amount € 2,500,000 (EUR)
Organisation INTERREG IIIC North 
Sector Public
Country France
Start 03/2013 
End 03/2015
 
Title Sex change markers 
Description We have developed a series of molecular tools to determine whether crustaceans are being feminised or demasculinized by pollutants. 
Type Of Material Physiological assessment or outcome measure 
Provided To Others? No  
Impact Only just published and developed 
URL http://www.port.ac.uk/uopnews/2014/11/10/shellfish-win-battle-against-being-feminised/
 
Title Emarinus Trancriptome 
Description Collection of transcriptomic sequences from male, female and intersex crustaceans funded by NERC made public to the scientific community 
Type Of Material Database/Collection of data 
Year Produced 2014 
Provided To Others? Yes  
Impact Only just made the data public 
URL http://gmod.org/wiki/GBrowse
 
Description IgNobel Talk 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Public/other audiences
Results and Impact Some media articles

Further media attention to research
Year(s) Of Engagement Activity 2014
URL http://www.port.ac.uk/uopnews/2014/04/03/ig-nobel-event-celebrates-weird-and-wonderful-research/
 
Description NERC Podcast - Planet Earth 
Form Of Engagement Activity A press release, press conference or response to a media enquiry/interview
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Media (as a channel to the public)
Results and Impact Podcast on the development to molecular tools to determine whether crustaceans are changing sex in response to pollution.
Year(s) Of Engagement Activity 2015
URL http://planetearth.nerc.ac.uk/multimedia/story.aspx?id=1785&cookieConsent=A