Molecular Characterization of Biological Rhythms in the beach amphipod Talitrus saltator (Montagu)

Abstract

The supralittoral sandhopper, Talitrus saltator (Montagu, 1808) exhibits prominent circadian behavioural phenotypes such as locomotor activity rhythm and time-compensated celestial navigation. To investigate the molecular underpinnings of these behaviours, a circadian transcriptome was assembled from time-series RNA-seq data with template from brain tissue samples. Rhythmically expressed clock and clock-associated genes were identified and compared to homologous sequences in the literature. Investigating the time-compensation aspect of Talitrus navigation, evidence for an anatomically discrete antennal moon compass clock was discovered while solar orientation was found to be antennae independent. Further, the time-compensation mechanism of solar navigation and rhythmic locomotor activity is likely linked to clock gene expression as molecular and behavioural phenotypes agree. Immunohistochemical staining indicated at least four neurons as potential central pacemaker cells in the cerebral ganglia. The circadian clock output was also researched through analysing ‘crustacean hyperglycaemic hormone’ (CHH) which was- contrary to other crustaceans- not expressed rhythmically in the brain. Immunolocalization of CHH protein and mRNA confirm distinct staining patterns in agreement with findings in the literature. The present thesis connect molecular data with behavioural phenotypes and provides clear progress in the research of biological rhythms in arthropods

Date of Award	2018
Original language	English
Awarding Institution	Aberystwyth University
Supervisor	David Wilcockson (Supervisor)