Mulvihill, Eoin
(2014)
Transcriptomic and proteomic analysis of
anhydrobiosis in Panagrolaimus superbus
and Caenorhabditis elegans dauer larvae.
PhD thesis, National University of Ireland Maynooth.
Abstract
Many organisms are able to survive the loss of up to 95% of their cellular fluid by
entering a state of suspended animation known as anhydrobiosis. The mechanisms which
allow these organisms to survive desiccation are poorly understood. The nematodes
Panagrolaimus superbus and Caenorhabditis elegans are able to survive extreme
desiccation. These nematodes have contrasting strategies for surviving desiccation
perhaps defined by the habitats in which they evolved. P. superbus was originally isolated
in 1981 from a gull’s nest in Surtsey, Iceland. In contrast C. elegans adults inhabit rotting
fruit, a stable environment, less susceptible to desiccation. However, C. elegans does
possess a stress resistant dauer larval stage in which the larvae are able to survive
desiccation. The aim of this project was to identify the genes and proteins involved in
desiccation tolerance in P. superbus and C. elegans dauer larvae.
The genes which were differentially expressed in response to desiccation and recovery in
P. superbus and C. elegans dauer larvae were identified using RNA-seq technology. The
mechanisms of desiccation tolerance were further investigated in P. superbus and C.
elegans dauer larvae by using quantitative proteomic methods. In C. elegans dauer larvae
and P. superbus, the following processes and pathways were implicated in the response to
desiccation at both the transcriptome and proteome level: molecular chaperone activity,
molecular shield activity, antioxidants, compatible solutes, the ubiquitin proteasome
system, autophagy, DNA repair, cellular repair and response to pathogens. While there
was much overlap in the identities of the genes and proteins which were up-regulated in
response to dehydration, differences were also observed, which could be a reflection of
the differences in the adaptive strategies used by these two nematode species to combat
desiccation. Desiccation responsive gene candidates were selected for functional analyses
using RNAi in C. elegans dauer larvae. This RNAi study revealed the importance of
genes encoding hydrophilic proteins, molecular chaperones, trehalose phosphate synthase
and glycerol kinase, as well as previously uncharacterised genes in enabling C. elegans
dauer larvae to successfully survive desiccation.
The data presented in this thesis show that substantial reorganisation of cellular structures
and mobilization of cellular protection repair systems occurs in C. elegans dauer larvae
and P. superbus in response to desiccation, indicating that anhydrobiotic survival requires
a major, integrated organismal response.
| Item Type: |
Thesis
(PhD)
|
| Keywords: |
Transcriptomic; proteomic analysis;
anhydrobiosis; Panagrolaimus superbus;
Caenorhabditis elegans dauer larvae; |
| Academic Unit: |
Faculty of Science and Engineering > Biology |
| Item ID: |
7724 |
| Depositing User: |
IR eTheses
|
| Date Deposited: |
11 Jan 2017 16:10 |
| URI: |
|
| Use Licence: |
This item is available under a Creative Commons Attribution Non Commercial Share Alike Licence (CC BY-NC-SA). Details of this licence are available
here |
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