Investigating the function of PINK1 in cancer development and pathogenesis

PTEN‐induced kinase 1 (PINK1) was identified initially in cancer cells as a gene up‐regulated by overexpression of the central tumour suppressor, PTEN. Loss‐of‐function mutations in PINK1 were discovered subsequently to cause autosomal recessive Parkinsonʹs disease (ARPD). Despite much research focusing on the proposed mechanism(s) through which loss of PINKI function causes neurodegeneration, few studies have focused on a direct role for this serine/threonine kinase in cancer biology. The focus of this thesis was to examine a direct role for PINK1 function in tumourigenesis. Initial studies showed that loss of PINK1 reduces tumour‐associated phenotypes including cell growth, colony formation and invasiveness, in several cell types in vitro, indicating a pro‐tumourigenic role for PINK1 in cancer. Furthermore, results revealed for the first time that PINK1 deletion, examined in mouse embryonic fibroblasts (MEFS) from PINK1 knock‐out animals, causes cell cycle defects, whereby cells arrest at in cytokinesis, giving rise to a highly significant increase in the number of multinucleated cells. This results in several key changes in the expression profile of cell cycle associated protein. In addition, PINK1‐deficient MEFs were found to resist cell cycle exit, with a proportion of cells remaining in proliferative phases upon removal of serum. The ability of cells to progress through mitosis conferred by PINK1 expression was independent of its kinase activity, while the cell cycle exit following serum withdrawal was kinase dependent. Investigations into the mechanism through which loss of PINK1 function gives rise to cell cycle defects revealed that dynamin related protein 1 (Drp1)‐mediated mitochondrial fission is enhanced in PINK1‐ deficient MEFs, and that increased expression of Drp1 on mitochondria and activation of Drp1 is highly significant in PINK1‐deficient multinucleated cells. Deregulated and increased levels and activation of mitochondrial fission via Drp1 was shown to be a major feature of cell cycle defects caused by PINK1 deletion, both during progression through G2/M and cell cycle exit following serum removal. Altered PINK1 localisation was also observed during progression of mitosis, and upon serum deprivation. Thus, PINK1 dissociated from the mitochondria during the mitotic phases and localised to mitochondria upon serum withdrawal. During serum withdrawal deletion of PINK1 disabled the ability of MEFs to increase mitochondrial membrane potential (ΔΨm), and increase autophagy. This was co‐incident with increased mitochondrial fission, and increased localisation of Drp1 to mitochondria following serum deprivation. Together, this indicates an inability of PINK1‐negative cells to respond protectively to this stress‐induced state, primarily via impaired mitochondrial function. In contrast, PINK1 overexpression was found to protect cells from DNA damage following treatment with oxidants. In addition, deletion of PINK1 blocked the ability of cells to re‐enter the cell cycle in response to insulin‐like growth factor‐1 (IGF‐1), a major cancer promoting agonistwhich acts primarily via PI3‐kinase/Akt activation. Furthermore, PINK1 mRNA expression was significantly increased following serum deprivation of MCF‐7 cells, and this was rendered more significant upon additional inhibition of PI3‐kinase. Conversely, IGF‐1 activation of PI3‐kinase/Akt causes a time‐dependent and significant reduction of PINK1 mRNA expression that was PI3‐kinase dependent. Together these results indicate that PINK1 expression is necessary for IGF‐1 signalling and is regulated reciprocally in the absence and presence of IGF‐1, via PI3‐kinase/Akt, a signalling system which has major tumour‐promoting capacity in cancer cell biology. The results of this thesis indicate PINK1 is a candidate tumour-promoting gene which has a significant function in the regulation of the cell cycle, and growth factor responses, at key cell cycle checkpoints, namely, during progression through G2/M and during exit of the cell cycle following removal of serum. Furthermore, the results reveal that the regulation of mitochondrial fission and Drp1 function is mechanistically important in the regulation of cell cycle control by PINK1. As deregulation of the cell cycle is linked to both tumourigenesis and neurodegeneration, the findings of this thesis are of importance not just for understanding cancer biology, but also in the context of PINK1‐associated neurodegeneration.

The role of synchronization in digital communications using chaos - Part II: Chaotic modulation and chaotic synchronization.

For pt. I see ibid., vol. 44, p. 927-36 (1997). In a digital communications system, data are transmitted from one location to another by mapping bit sequences to symbols, and symbols to sample functions of analog waveforms. The analog waveform passes through a bandlimited (possibly time-varying) analog channel, where the signal is distorted and noise is added. In a conventional system the analog sample functions sent through the channel are weighted sums of one or more sinusoids; in a chaotic communications system the sample functions are segments of chaotic waveforms. At the receiver, the symbol may be recovered by means of coherent detection, where all possible sample functions are known, or by noncoherent detection, where one or more characteristics of the sample functions are estimated. In a coherent receiver, synchronization is the most commonly used technique for recovering the sample functions from the received waveform. These sample functions are then used as reference signals for a correlator. Synchronization-based coherent receivers have advantages over noncoherent receivers in terms of noise performance, bandwidth efficiency (in narrow-band systems) and/or data rate (in chaotic systems). These advantages are lost if synchronization cannot be maintained, for example, under poor propagation conditions. In these circumstances, communication without synchronization may be preferable. The theory of conventional telecommunications is extended to chaotic communications, chaotic modulation techniques and receiver configurations are surveyed, and chaotic synchronization schemes are described

The effect of variability in the powder/liquid ratio on the strength of zinc phosphate cement

Aim: To investigate (a) variability in powder/liquid proportioning (b) effect of the extremes of any such variability on diametral tensile strength (DTS), in a commercial zinc phosphate cement. Statistical analyses (a = 0.05) were by Student's t-test in the case of powder/liquid ratio and one-way ANOVA and Tukey HSD for for pair-wise comparisons of mean DTS. The Null hypotheses were that (a) the powder-liquid mixing ratios observed would not differ from the manufacturer's recommended ratio (b) DTS of the set cement samples using the extreme powder/liquid ratios observed would not differ from those made using the manufacturer's recommended ratio. Methodology: Thirty-four undergraduate dental students dispensed the components according to the manufacturer's instructions. The maximum and minimum powder/liquid ratios (m/m), together with the manufacturer's recommended ratio (m/m), were used to prepare cylindrical samples (n = 3 x 34) for DTS testing. Results: Powder/liquid ratios ranged from 2.386 to 1.018.The mean ratio (1.644 (341) m/m) was not significantly different from the manufacturer's recommended value of 1.718 (p=0.189). DTS values for the maximum and minimum ratios (m/m), respectively, were both significantly different from each other (p<0.001) and from the mean value obtained from the manufacturer's recommended ratio (m/m) (p<0.001). Conclusions: Variability exists in powder/liquid ratio (m/m) for hand dispensed zinc phosphate cement. This variability can affect the DTS of the set material.

The transformation of Ireland 1958 - 93: the role of ideas in punctuating institutional path dependency at critical junctures

Ireland experienced two critical junctures when its economic survival was threatened: 1958/9 and 1986/7. Common to both crises was the supplanting of long established practices, that had become an integral part of the political culture of the state, by new ideas that ensured eventual economic recovery. In their adoption and implementation these ideas also fundamentally changed the institutions of state – how politics was done, how it was organised and regulated. The end result was the transformation of the Irish state. The main hypothesis of this thesis is that at those critical junctures the political and administrative elites who enabled economic recovery were not just making pragmatic decisions, their actions were influenced by ideas. Systematic content analysis of the published works of the main ideational actors, together with primary interviews with those actors still alive, reveals how their ideas were formed, what influenced them, and how they set about implementing their ideas. As the hypothesis assumes institutional change over time historical institutionalism serves as the theoretical framework. Central to this theory is the idea that choices made when a policy is being initiated or an institution formed will have a continuing influence long into the future. Institutions of state become ‘path dependent’ and impervious to change – the forces of inertia take over. That path dependency is broken at critical junctures. At those moments ideas play a major role as they offer a set of ready-made solutions. Historical institutionalism serves as a robust framework for proving that in the transformation of Ireland the role of ideas in punctuating institutional path dependency at critical junctures was central.

Principles and prejudice: The erosion of fairness in admissibility determinations relating to historic child sexual abuse trials in Ireland

This thesis interrogates the construction of fairness to the accused in historic child sexual abuse trials in Ireland. The protection of fairness is a requirement of any trial that claims to adhere to the rule of law. Historic child sexual abuse trials, in which the charges relate to events that are alleged to have taken place decades previously, present serious challenges to the ability of the trial process to safeguard fairness. They are a litmus test of the courts’ commitment to fairness. The thesis finds that in historic abuse trials fairness to the accused has been significantly eroded and that therefore the Irish Courts have failed to respect the core of the rule of law in these most serious of prosecutions. The thesis scrutinises two bodies of case law, both of which deal with the issue of whether evidence should reach the jury. First, it examines the decisions on applications brought by defendants seeking to prohibit their trial. The courts hearing prohibition applications face a dilemma: how to ensure the defendant is not put at risk of an unfair trial, while at the same time recognising that delay in reporting is a defining feature of these cases. The thesis traces the development of the prohibition case law and tracks the shifting interpretations given to fairness by the courts. Second, the thesis examines what fairness means in the superior courts’ decisions regarding the admissibility of the following kinds of evidence, each of which presents particular challenges to the ability of the trial to safeguard fairness: evidence of multiple complainants; evidence of recovered memories and evidence of complainants’ therapeutic records. The thesis finds that in both bodies of case law the Irish courts have hollowed out the meaning of fairness. It makes proposals on how fairness might be placed at the heart of courts’ decisions on admissibility in historic abuse trials. The thesis concludes that the erosion of fairness in historic abuse trials is indicative of a move away from the liberal model of criminal justice. It cautions that unless fairness is prioritised in historic child sexual abuse trials the legitimacy of these trials and that of all Irish criminal trials will be contestable.

Investigation into the role of autophagy in chemoresistance in oesophageal cancer and evaluation of novel prognostic markers

Accepted Version

The Rpf/DSF system and the regulation of virulence in the plant pathogen Xanthomonas campestris

The full virulence of Xanthomonas campestris pv. campestris (Xcc) to plants depends upon cell-to-cell signalling mediated by the signal molecule DSF (for diffusible signal factor), that has been characterised as cis-11-methyl-2-dodecenoic acid. DSF-mediated signalling regulates motility, biofilm dynamics and the synthesis of particular virulence determinants. The synthesis and perception of the DSF signal molecule involves products of the rpf (regulation of pathogenicity factors) gene cluster. DSF synthesis is fully dependent on RpfF, which encodes a putative enoyl-CoA hydratase. A two-component system, comprising the complex sensor histidine kinase RpfC and the HD-GYP domain regulator RpfG, is implicated in DSF perception. The HD-GYP domain of RpfG is a phosphodiesterase working on cyclic di-GMP; DSF perception is thereby linked to the turnover of this intracellular second messenger. The full range of regulatory influences of the Rpf/DSF system and of cyclic di-GMP in Xcc has yet to be established. In order to further characterise the Rpf/DSF regulatory network in Xcc, a proteomic approach was used to compare protein expression in the wildtype and defined rpf mutants. This work shows that the Rpf/DSF system regulates a range of biological functions that are associated with virulence and biofilm formation but also reveals new functions mediated by DSF regulation. These functions include antibiotic resistance, detoxification and stress tolerance. Mutational analysis showed that several of these regulated protein functions contribute to virulence in Chinese radish. Interestingly, it was demonstrated that different patterns of protein expression are associated with mutations of rpfF, rpfC and rpfG. This suggests that RpfG and RpfC have broader roles in regulation other than perception and transduction of DSF. Taken together, this analysis indicates the broad and complex regulatory role of Rpf/DSF system and identifies a number of new functions under Rpf/DSF control, which were shown to play a role in virulence.

The role of metabolism in the pathogenesis of adherent invasive Escherichia coli (AIEC)

Crohn’s disease (CD) is a chronic, relapsing inflammatory condition affecting the gastrointestinal tract of humans, of which there is currently no cure. The precise etiology of CD is unknown, although it has become widely accepted that it is a multifactorial disease which occurs as a result of an abnormal immune response to commensal enteric bacteria in a genetically susceptible host. Recent studies have shown that a new group of Escherichia coli, called Adherent Invasive Escherichia coli (AIEC) are present in the guts of CD patients at a higher frequency than in healthy subjects, suggesting that they may play a role in the initiation and/or maintenance of the inflammation associated with CD. Two phenotypes define an AIEC and differentiate them from other groups of E. coli. Firstly, AIEC can adhere to and invade epithelial cells; and secondly, they can replicate in macrophages. In this study, we use a strain of AIEC which has been isolated from the colonic mucosa of a CD patient, called HM605, to examine the relationship between AIEC and the macrophage. We show, using a systematic mutational approach, that while the Tricarboxylic acid (TCA) cycle, the glyoxylate pathway, the Entner-Doudoroff (ED) pathway, the Pentose Phosphate (PP) pathway and gluconeogenesis are dispensable for the intramacrophagic growth of HM605, glycolysis is an absolute requirement for the ability of this organism to replicate intracellularly. We also show that HM605 activates the inflammasome, a major driver of inflammation in mammals. Specifically, we show that macrophages infected with HM605 produce significantly higher levels of the pro-inflammatory cytokine IL-1β than macrophages infected with a non-AIEC strain, and we show by immunoblotting that this is due to cleavage of caspase-1. We also show that macrophages infected with HM605 exhibit significantly higher levels of pyroptosis, a form of inflammatory cell death, than macrophages infected with a non-AIEC strain. Therefore, AIEC strains are more pro-inflammatory than non-AIEC strains and this may have important consequences in terms of CD pathology. Moreover, we show that while inflammasome activation by HM605 is independent of intracellular bacterial replication, it is dependent on an active bacterial metabolism. Through the establishment of a genetic screen aimed at identifying mutants which activate the inflammasome to lower levels than the wild-type, we confirm our observation that bacterial metabolism is essential for successful inflammasome activation by HM605 and we also uncover new systems/structures that may be important for inflammasome activation, such as the BasS/BasR two-component system, a type VI secretion system and a K1 capsule. Finally, in this study, we also identify a putative small RNA in AIEC strain LF82, which may be involved in modulating the motility of this strain. Overall this works shows that, in the absence of specialised virulence factors, the ability of AIEC to metabolise within the host cell may be a key determinant of its pathogenesis.

The quality of deliberation in Northern Ireland's district policing partnerships

This study uses theoretical based deliberative democratic dimensions to measure the deliberative quality of Northern Ireland’s District Policing Partnership (DPP) meetings in public. The study combines Habermasian, and Young’s deliberative concepts to create an Augmented Discourse Quality Index. This Augmented DQI is employed by this research as am empirical instrument to establish the true deliberative nature of these DPP meetings in public. The overall goal of this study is two-fold. First; to gain an in-depth understanding of Northern Ireland’s DPPs in relation to deliberative democratic theory, specifically regarding how these policing/public partnerships stand up under a deliberative democratic lens. The second goal is to provide a possible framework by which deliberative quality can be more accurately measured. In that frameworks which are designed to measure deliberative quality should include not only the dimensions for rational participation, but also include broader terms of communication such as greeting, rhetoric and story-telling.

Studies on factors relating to the development of defects in commercial cheese

Defects in commercial cheese result in a downgrading of the final cheese and a consequential economic loss to the cheese producer. Developments of defects in cheese are often not fully understood and therefore not controllable by the producer. This research investigated the underlying factors in the development of split and secondary fermentation defect and of pinking defects in commercial Irish cheeses. Split defect in Swiss-type cheese is a common defect associated with eye formation and manifests as slits and cracks visible in the cut cheese loaf (Reinbold, 1972; Daly et al., 2010). No consensus exists as to the definitive causes of the defect and possible factors which may contribute to the defect were reviewed. Models were derived to describe the relationship between moisture, pH, and salt levels and the distance from sample location to the closest external block surface during cheese ripening. Significant gradients within the cheese blocks were observed for all measured parameters in cheeses at 7 day post/after manufacture. No significant pH gradient was found within the blocks on exit from hot-room ripening and at three months post exit from the hot-room. Moisture content reached equilibrium within the blocks between exit from hot-room and 3 months after exit from hot-room while salt and salt-to-moisture levels had not reached equilibrium within the cheese blocks even at three months after exit from hot-room ripening. A characterisation of Swiss-type cheeses produced from a seasonal milk supply was undertaken. Cheeses were sampled on two days per month of the production year, at three different times during the manufacturing day, at internal and external regions of the cheese block and at four ripening time points (7 days post manufacture, post hot-room, 14 days post hot-room and 3 months in a cold room after exit from hot-room). Compositional, biochemical and microbial indices were determined, and the results were analysed as a splitplot with a factorial arrangement of treatments (season, time of day, area) on the main plot and ripening time on the sub-plot. Season (and interactions) had a significant effect on pH and salt-in-moisture levels (SM), mean viable counts of L. helveticus, propionic acid and non-starter lactic acid bacteria, levels of primary and secondary proteolysis and cheese firmness. Levels of proteolysis increased significantly during hot-room ripening but also during cold room storage, signifying continued development of cheese ripening during cold storage (> 8°C). Rheological parameters (e.g. springiness and cohesiveness) were significantly affected by interactions between ripening and location within cheese blocks. Time of day of manufacture significantly affected mean cheese calcium levels at 7 days post manufacture and mean levels of arginine and mean viable counts of NSLAB. Cheeses produced during the middle of the production day had the best grading scores and were more consistent compared to cheeses produced early or late during day of manufacture. Cheeses with low levels of S/M and low values of resilience were associated with poor grades at 7 days post manufacture. Chesses which had high elastic index values and low values of springiness in the external areas after exit from hot-room ripening also obtained good commercial grades. Development of a pink colour defect is an intermittent defect in ripened cheese which may or may not contain an added colourant, e.g., annatto. Factors associated with the defect were reviewed. Attempts at extraction and identification of the pink discolouration were unsuccessful. The pink colour partitioned with the water insoluble protein fraction. No significant difference was observed between ripened control and defect cheese for oxygen levels and redox potential or for the results of elemental analysis. A possible relationship between starter activity and defect development was established in cheeses with added coulourant, as lower levels of residual galactose and lactose were observed in defective cheese compared to control cheese free of the defect. Swiss-type cheese without added colourant had significantly higher levels of arginine and significantly lower lactate levels. Flow cell cytometry indicated that levels of bacterial cell viability and metabolic state differed between control and defect cheeses (without added colourant). Pyrosequencing analysis of cheese samples with and without the defect detected the previously unreported bacteria in cheese, Deinococcus thermus (a potential carotenoid producer). Defective Swiss-type cheeses had elevated levels of Deinococcus thermus compared to control cheeses, however the direct cause of pink was not linked to this bacterium alone. Overall, research was undertaken on underlying factors associated with the development of specific defects in commercial cheese, but also characterised the dynamic changes in key microbial and physicochemical parameters during cheese ripening and storage. This will enable the development of processing technologies to enable seasonal manipulation of manufacture protocols to minimise compositional and biochemical variability and to reduce and inhibit the occurrence of specific quality defects.

The role of structure in the electrochemical performance of nanostructured metal oxides for lithium ion battery anodes

The Li-ion battery has for a number of years been a key factor that has enabled an ever increasing number of modern consumer devices, while in recent years has also been sought to power a range of emerging electric and hybrid electric vehicles. Due to their importance and popularity, a number of characteristics of Li-ion batteries have been subjected to intense work aimed at radical improvement. Although electrode material selection intrinsically defines characteristics like maximum capacity or voltage, engineering of the electrode structure may yield significant improvements to the lifetime performance of the battery, which would not be available if the material was used in its bulk form. The body of work presented in this thesis describes the relationship between the structure of electrochemically active materials and the course of the electrochemical processes occurring within the electrode. Chapter one describes the motivation behind the research presented herein. Chapter two serves to highlight a number of key advancements which have been made and detailed in the literature over recent years, pertaining to the use of nanostructured materials in Li-ion technology. Chapter three details methods and techniques applied in developing the body of work presented in this thesis. Chapter four details structural, molecular and electrochemical characteristics of tin oxide nanoparticle based electrodes, with particular emphasis on the relationship between the size distribution and the electrode performance. Chapter five presents findings of structural, electrochemical and optical study of indium oxide nanoparticles grown on silicon by molecular beam epitaxy. In chapter 6, tin oxide inverted opal electrodes are investigated for the conduct of the electrochemical performance of the electrodes under varying rate of change of potential. Chapter 7 presents the overall conclusions drawn from the results presented in this thesis, coupled with an indication of potential future work which may be explored further.

Characterisation of the role of Fas in intestinal inflammation and cancer

Background: The role of Fas (CD95) and its ligand, Fas ligand (FasL/CD95L), is poorly understood in the intestine. Whilst Fas is best studies in terms of its function in apoptosis, recent studies suggest that Fas ligation may mediate additional, non-apoptotic functions such as inflammation. Toll like Receptors (TLRs) play an important role in mediating inflammation and homeostasis in the intestine. Recent studies have shown that a level of crosstalk exists between the Fas and TLR signalling pathways but this has not yet been investigated in the intestine. Aim: The aim of this study was to evaluate potential cross-talk between TLRs and Fas/FasL system in intestinal cancer cells. Results: Treatment with TLR4 and TLR5 ligands, but not ligands for TLR2 and TLR9 increased the expression of Fas and FasL in intestinal cancer cells in vitro. Consistent with this, expression of Fas and FasL was reduced in the distal colon tissue from germ-free (GF), TLR4 and TLR5 knock-out (KO) mice but was unchanged in TLR2KO tissue, suggesting that intestinal cancer cells display a degree of specificity in their ability to upregulate Fas and FasL expression in response to TLR ligation. Expression of both Fas and FasL was significantly reduced in TRIF KO tissue, indicating that signalling via TRIF by TLR4 and TLR5 agonists may be responsible for the induction of Fas and FasL expression in intestinal cancer cells. In addition, modulating Fas signalling using agonistic anti-Fas augmented TLR4 and TLR5-mediated tumour necrosis factor alpha (TNFα) and interleukin 8 (IL)-8 production by intestinal cancer cells, suggesting crosstalk occurs between these receptors in these cells. Furthermore, suppression of Fas in intestinal cancer cells reduced the ability of the intestinal pathogens, Salmonella typhimurium and Listeria monocytogenes to induce the expression of IL-8, suggesting that Fas signalling may play a role in intestinal host defence against pathogens. Inflammation is known to be important in colon tumourigenesis and Fas signalling on intestinal cancer cells has been shown to result in the production of inflammatory mediators. Fas-mediated signalling may therefore play a role in colon cancer development. Suppression of tumour-derived Fas by 85% led to a reduction in the tumour volume and changes in tumour infiltrating macrophages and neutrophils. TLR4 signalling has been shown to play a role in colon cancer via the recruitment and activation of alternatively activated immune cells. Given the crosstalk seen between Fas and TLR4 signalling in intestinal cancer cells in vitro, suppressing Fas signalling may enhance the efficacy of TLR4 antagonism in vivo. TLR4 antagonism resulted in smaller tumours with fewer infiltrating neutrophils. Whilst Fas downregulation did not significantly augment the ability of TLR4 antagonism to reduce the final tumour volume, Fas suppression may augment the anti-tumour effects of TLR4 antagonism as neutrophil infiltration was further reduced upon combinatorial treatment. Conclusion: Together, this study demonstrates evidence of a new role for Fas in the intestinal immune response and that manipulating Fas signalling has potential anti-tumour benefit.

Keeping their heads down: Shame and pride in the stories of Protestants in the Irish Republic

This study draws on a number of in-depth interviews to explore the ethnic aspect of Protestantism in the Republic of Ireland. We explore themes of shame and pride around issues of identity, together with a sense of loss of a minority rapidly losing cultural distinctiveness. Following Ireland‘s division, the ordinary Protestants of the south, comprising a range of religious denominations bound by history, intermarriage and culture, found themselves in a society in which their story was rarely told. The dominant narrative was one of a Catholic people, long oppressed by a wealthy Protestant minority. The story of ordinary Protestants, including those in rural and urban poverty, went largely unheard. Today, ordinary Protestants – small farmers, shop keepers, housewives – tell the story of Ireland as seen through their family‘s narratives. Themes of pride and shame, often intertwined, form a thread that binds their testimony, drawing on family, personal and local history, folklore and statements of identity.

The Aarhus Convention and its implementation in Ireland: strengthening the role of NGOs in environmental governance

One of the most striking features of the 1998 Aarhus Convention on Access to Information, Public Participation in Decision-making and Access to Justice in Environmental Matters is the leading role envisaged for environmental nongovernmental organisations (ENGOs) in furthering compliance with environmental law. The Convention aims to secure the special status of ENGOs in environmental governance procedures by guaranteeing procedural rights of access to information, participation in decision-making and access to review mechanisms. Although Ireland did not become a Party to the Convention until September 2012, the Aarhus procedural rights were already guaranteed under European Union (EU) law. The EU has been a Party to the Aarhus Convention since May 2005 and has adopted a number of legislative measures to implement the Convention. This thesis examines the evolving role of ENGOs in environmental governance in Ireland. It provides a doctrinal analysis of the impact of the Aarhus Convention and EU law on Irish law and governance arrangements involving ENGOs. The thesis considers the extent to which Ireland has delivered faithfully on the standards set by the Aarhus Convention to facilitate ENGOs to fulfil the role envisaged for them under the Convention.