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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Comprehensive fish health assessment and parasitological investigation of alien and indigenous fishes from the Amatola region, South Africa / Kyle Joseph McHugh

McHugh, Kyle Joseph January 2015 (has links)
The conservation of biodiversity and endemism in South Africa’s freshwater aquatic ecosystems is a high priority, particularly in the Cape Floristic Region. However, the perception that South Africa lacks suitable fish species for recreational angling, aquaculture and biological control, led to the widespread introduction and use of alien fish species. As a result, formal stocking programs have seen the introduction of five of the world’s top 100 invasive species into South Africa (Dudgeon et al. 2006). According to Dudgeon et al. (2006) freshwater ecosystems are the most endangered ecosystem in the world. The threats to freshwater biodiversity, according to Dudgeon et al. (2006), can be grouped into five categories that interact with one another: overexploitation, water pollution, flow modifications, destruction of habitat and invasion by exotic species. This PhD study took place in the Amatola region of the Eastern Cape Province, South Africa. The Amatola region is a rural area with no large-scale mining or industrial developments, only localised settlements. These developments are mainly situated around impoundments, because of the resources such as water and food that they provide. Thus the dams within the Amatola region should theoretically have no major industrial stressors on them. The three impoundments studied were Binfield Park, Sandile and Wriggleswade Dams. Binfield Park Dam is a 260ha impoundment. It impounds the Tyume River and is used by both subsistence anglers from the local communities and occasionally by recreational bass anglers. Sandile Dam is a 146ha impoundment and is the smallest of the three dams in this study. It impounds the Wolf and Keiskamma Rivers. Wriggleswade Dam is a 1000ha impoundment used extensively by recreational bass and carp anglers, and impounds the Kubusi River. There is a paucity of information regarding the health of the indigenous and alien fish species from the study region, as well as on the parasite diversity of these various fish species. In order to fill the gaps in the information the following hypothesis was proposed. That the necropsy based and histology based fish health assessment can be successfully implemented as tools to assess the effects of heavy metal pollution and alien fish parasites in freshwater fish from selected impoundments in the Amatola region, Eastern Cape Province, South Africa. In order to achieve this hypothesis the main aim of this study will be to use the necropsy- and histology- based fish health assessment to determine the health status of the fish species in these impoundments as well as to understand the potential threat of water pollution and fish parasites. Fish were sampled with the aid of gill nets, fyke nets and by angling from each of the three impoundments over three surveys in July 2011, and March and August 2012. Following capture fish were transported to a field laboratory in aerated containers. At the field laboratory the fish were examined and dissected using the methods recommended by Adams et al. (1993) for a necropsy-based fish health assessment. Gills, livers, kidneys and gonads samples were also collected for histological analysis. Macroscopic and histology-based fish health assessment index was used, as well the analysis of muscle tissue of Micropterus salmoides and surface water and sediment from Binfield Park, Sandile and Wriggleswade Dams. It was shown that, according to the macroscopic fish health assessment index, M. salmoides in Wriggleswade Dam had a higher FHAI score compared to those in Binfield Park and Sandile Dam, there were no significant differences between the FHAI scores. However, the cause of the higher FHAI in the Wriggleswade Dam was because of the external skin damage caused by the presence of the alien parasite Lernaea cyprinacea. The histology-based fish health assessment index, however, showed that M. salmoides from Binfield Park had significantly higher histology Fish Index (IFISH) scores compared to those in Sandile and Wriggleswade Dams. The main contributors to the high IFISH score of Binfield Park were the significantly high Liver Index (IL) and Kidney Index (IK). The increased severity of the alterations observed in the liver and kidney tissue of the Binfield Park M. salmoides samples may have been as a result of the high concentration of mercury found in the muscle tissue of M. salmoides. The water quality and metals detected in the water of Binfield Park, Sandile and Wriggleswade Dams were all below the target water quality guideline values, as well as below those of previous research into the nutrients and presence of metals in these impoundments. The sediment metal analysis showed that the levels of Co, Mn and Ni were above the target guideline levels for Binfield Park, Sandile and Wriggleswade Dams, Cu was above target guidelines levels for Sandile Dam, and uranium was above the target guideline concentrations for Wriggleswade Dam. Binfield Park Dam had significantly high levels of mercury in the muscle tissue of M. salmoides, while Sandile Dam had significantly high levels of zinc in the muscle tissue of M. salmoides. It was shown that M. salmoides from each of the three impoundments are in a healthy state according to the parameters assessed. However, the presence of heavy metals, particularly mercury, uranium and zinc, do indicate the presence of human activities. The indigenous parasites of Anguilla mossambica have been well documented including the gastrointestinal nematode Paraquimperia africana, and the stomach nematode Heliconema africanum. Indigenous parasites such as the swimbladder nematode Anguillicola papernai had no effect on the condition factor of infected and uninfected eels. However, the damage caused by the alien parasites were evident, including the first documented effects of the alien gill monogenean Pseudodactylogyrus anguillae on indigenous wild populations of the longin fin eel A. mossambica from the Eastern Cape, South Africa. Histological observations indicated that an alien gill monogenean caused hyperplasia, increase in mucous cells, rupture of pillar cells as well as telangiectasia. This alien parasite has invaded the Keiskamma and Kei River systems in the Eastern Cape, South Africa. According to the macroscopic fish health assessment index, A. mossambica from Binfield Park, Sandile and Wriggleswade Dams are in a healthy state. However, the histology-based health assessment highlighted that the effects on P. anguillae have a severe negative impact on the health of A. mossambica. Using the macroscopic and histology-based fish health assessment, a comprehensive investigation into the fish health status of Mugil cephalus and Myxus capensis from Binfield Park Dam revealed that human effects and parasites are not the only threats to freshwater fish. Nephrocalcinosis is a non-infectious kidney disease which is characterised by abnormal calcium deposition in the kidneys of humans and some fish species. According to the macroscopic and histology-based fish health assessment, the M. cephalus and M. capensis are not in a healthy condition. The macroscopic and histology-based fish assessment indices are not stressor-specific, and therefore the cause of the poor health state of these two fish species could not be determined. A possible suggestion for the poor health of these two species is the age of the species. Because the two mullet species were stocked into Binfield Park Dam, Ellender et al. (2012) could successfully age them accurately to ten years of age, which is the upper limit of the life span for these species. Macroscopic and histology-based fish heath assessments were conducted on Labeo umbratus from Sandile Dam in order to determine the health of this species. Macroscopic and histology-based fish health assessment indicated that its L. umbratus are in a healthy state. The March 2012 survey specimens had a significantly higher macroscopic FHAI score than those from the July 2011 survey. The increased FHAI score was because of parasite infections, as well as discoloured livers and increased total blood plasma protein levels, which are indicators of nutritional state. However, the presence of the anchor worm parasite Lernaea barnimiana in low numbers had no significant impact on the health of L. umbratus. The effect of the alien anchor worm parasite Lernaea cyprinacea was shown on the transloacted small mouth yellowfish Labeobarbus aeneus. It was also shown that L. aeneus are, according the macroscopic FHAI and the histology-based fish health assessment index, in a healthy state. However, the high scores observed in the macroscopic fish health assessment index were primarily as a result of the presence of the alien parasite L. cyprinacea and its associated affects on the fish host. Because of the significant impact of this alien parasite species on the translocated host species, it can be assumed that this alien parasite species will have a negative effect on the health of indigenous fish species in the Great Kei River. It is clear from the results presented in this study that the necropsy based and histology based fish health assessment can be successfully implemented as tools to assess the effects of heavy metal pollution and alien fish parasites in freshwater fish from selected impoundments in the Amatola region, Eastern Cape Province, South Africa, thus the original hypothesis of this thesis is accepted. Based on work done in this research the gaps in research have been identified. Due to the high levels of mercury indentified in the muscle tissue of M. salmoides from Binfield Park Dam. A human health assessment and edibility should be conducted in order to determine if the fish from Binfield Park Dam is safe for human consumption. In order to conserve South Africa’s Freshwater fish biodiversity, country wide surveys of indigenous fish species must be undertaken so that the health and the parasite diversity can be evaluated. / PhD (Zoology), North-West University, Potchefstroom Campus, 2015
2

Comprehensive fish health assessment and parasitological investigation of alien and indigenous fishes from the Amatola region, South Africa / Kyle Joseph McHugh

McHugh, Kyle Joseph January 2015 (has links)
The conservation of biodiversity and endemism in South Africa’s freshwater aquatic ecosystems is a high priority, particularly in the Cape Floristic Region. However, the perception that South Africa lacks suitable fish species for recreational angling, aquaculture and biological control, led to the widespread introduction and use of alien fish species. As a result, formal stocking programs have seen the introduction of five of the world’s top 100 invasive species into South Africa (Dudgeon et al. 2006). According to Dudgeon et al. (2006) freshwater ecosystems are the most endangered ecosystem in the world. The threats to freshwater biodiversity, according to Dudgeon et al. (2006), can be grouped into five categories that interact with one another: overexploitation, water pollution, flow modifications, destruction of habitat and invasion by exotic species. This PhD study took place in the Amatola region of the Eastern Cape Province, South Africa. The Amatola region is a rural area with no large-scale mining or industrial developments, only localised settlements. These developments are mainly situated around impoundments, because of the resources such as water and food that they provide. Thus the dams within the Amatola region should theoretically have no major industrial stressors on them. The three impoundments studied were Binfield Park, Sandile and Wriggleswade Dams. Binfield Park Dam is a 260ha impoundment. It impounds the Tyume River and is used by both subsistence anglers from the local communities and occasionally by recreational bass anglers. Sandile Dam is a 146ha impoundment and is the smallest of the three dams in this study. It impounds the Wolf and Keiskamma Rivers. Wriggleswade Dam is a 1000ha impoundment used extensively by recreational bass and carp anglers, and impounds the Kubusi River. There is a paucity of information regarding the health of the indigenous and alien fish species from the study region, as well as on the parasite diversity of these various fish species. In order to fill the gaps in the information the following hypothesis was proposed. That the necropsy based and histology based fish health assessment can be successfully implemented as tools to assess the effects of heavy metal pollution and alien fish parasites in freshwater fish from selected impoundments in the Amatola region, Eastern Cape Province, South Africa. In order to achieve this hypothesis the main aim of this study will be to use the necropsy- and histology- based fish health assessment to determine the health status of the fish species in these impoundments as well as to understand the potential threat of water pollution and fish parasites. Fish were sampled with the aid of gill nets, fyke nets and by angling from each of the three impoundments over three surveys in July 2011, and March and August 2012. Following capture fish were transported to a field laboratory in aerated containers. At the field laboratory the fish were examined and dissected using the methods recommended by Adams et al. (1993) for a necropsy-based fish health assessment. Gills, livers, kidneys and gonads samples were also collected for histological analysis. Macroscopic and histology-based fish health assessment index was used, as well the analysis of muscle tissue of Micropterus salmoides and surface water and sediment from Binfield Park, Sandile and Wriggleswade Dams. It was shown that, according to the macroscopic fish health assessment index, M. salmoides in Wriggleswade Dam had a higher FHAI score compared to those in Binfield Park and Sandile Dam, there were no significant differences between the FHAI scores. However, the cause of the higher FHAI in the Wriggleswade Dam was because of the external skin damage caused by the presence of the alien parasite Lernaea cyprinacea. The histology-based fish health assessment index, however, showed that M. salmoides from Binfield Park had significantly higher histology Fish Index (IFISH) scores compared to those in Sandile and Wriggleswade Dams. The main contributors to the high IFISH score of Binfield Park were the significantly high Liver Index (IL) and Kidney Index (IK). The increased severity of the alterations observed in the liver and kidney tissue of the Binfield Park M. salmoides samples may have been as a result of the high concentration of mercury found in the muscle tissue of M. salmoides. The water quality and metals detected in the water of Binfield Park, Sandile and Wriggleswade Dams were all below the target water quality guideline values, as well as below those of previous research into the nutrients and presence of metals in these impoundments. The sediment metal analysis showed that the levels of Co, Mn and Ni were above the target guideline levels for Binfield Park, Sandile and Wriggleswade Dams, Cu was above target guidelines levels for Sandile Dam, and uranium was above the target guideline concentrations for Wriggleswade Dam. Binfield Park Dam had significantly high levels of mercury in the muscle tissue of M. salmoides, while Sandile Dam had significantly high levels of zinc in the muscle tissue of M. salmoides. It was shown that M. salmoides from each of the three impoundments are in a healthy state according to the parameters assessed. However, the presence of heavy metals, particularly mercury, uranium and zinc, do indicate the presence of human activities. The indigenous parasites of Anguilla mossambica have been well documented including the gastrointestinal nematode Paraquimperia africana, and the stomach nematode Heliconema africanum. Indigenous parasites such as the swimbladder nematode Anguillicola papernai had no effect on the condition factor of infected and uninfected eels. However, the damage caused by the alien parasites were evident, including the first documented effects of the alien gill monogenean Pseudodactylogyrus anguillae on indigenous wild populations of the longin fin eel A. mossambica from the Eastern Cape, South Africa. Histological observations indicated that an alien gill monogenean caused hyperplasia, increase in mucous cells, rupture of pillar cells as well as telangiectasia. This alien parasite has invaded the Keiskamma and Kei River systems in the Eastern Cape, South Africa. According to the macroscopic fish health assessment index, A. mossambica from Binfield Park, Sandile and Wriggleswade Dams are in a healthy state. However, the histology-based health assessment highlighted that the effects on P. anguillae have a severe negative impact on the health of A. mossambica. Using the macroscopic and histology-based fish health assessment, a comprehensive investigation into the fish health status of Mugil cephalus and Myxus capensis from Binfield Park Dam revealed that human effects and parasites are not the only threats to freshwater fish. Nephrocalcinosis is a non-infectious kidney disease which is characterised by abnormal calcium deposition in the kidneys of humans and some fish species. According to the macroscopic and histology-based fish health assessment, the M. cephalus and M. capensis are not in a healthy condition. The macroscopic and histology-based fish assessment indices are not stressor-specific, and therefore the cause of the poor health state of these two fish species could not be determined. A possible suggestion for the poor health of these two species is the age of the species. Because the two mullet species were stocked into Binfield Park Dam, Ellender et al. (2012) could successfully age them accurately to ten years of age, which is the upper limit of the life span for these species. Macroscopic and histology-based fish heath assessments were conducted on Labeo umbratus from Sandile Dam in order to determine the health of this species. Macroscopic and histology-based fish health assessment indicated that its L. umbratus are in a healthy state. The March 2012 survey specimens had a significantly higher macroscopic FHAI score than those from the July 2011 survey. The increased FHAI score was because of parasite infections, as well as discoloured livers and increased total blood plasma protein levels, which are indicators of nutritional state. However, the presence of the anchor worm parasite Lernaea barnimiana in low numbers had no significant impact on the health of L. umbratus. The effect of the alien anchor worm parasite Lernaea cyprinacea was shown on the transloacted small mouth yellowfish Labeobarbus aeneus. It was also shown that L. aeneus are, according the macroscopic FHAI and the histology-based fish health assessment index, in a healthy state. However, the high scores observed in the macroscopic fish health assessment index were primarily as a result of the presence of the alien parasite L. cyprinacea and its associated affects on the fish host. Because of the significant impact of this alien parasite species on the translocated host species, it can be assumed that this alien parasite species will have a negative effect on the health of indigenous fish species in the Great Kei River. It is clear from the results presented in this study that the necropsy based and histology based fish health assessment can be successfully implemented as tools to assess the effects of heavy metal pollution and alien fish parasites in freshwater fish from selected impoundments in the Amatola region, Eastern Cape Province, South Africa, thus the original hypothesis of this thesis is accepted. Based on work done in this research the gaps in research have been identified. Due to the high levels of mercury indentified in the muscle tissue of M. salmoides from Binfield Park Dam. A human health assessment and edibility should be conducted in order to determine if the fish from Binfield Park Dam is safe for human consumption. In order to conserve South Africa’s Freshwater fish biodiversity, country wide surveys of indigenous fish species must be undertaken so that the health and the parasite diversity can be evaluated. / PhD (Zoology), North-West University, Potchefstroom Campus, 2015
3

Vital Rates, Population Trends, and Habitat-Use Patterns of a Translocated Greater Sage-Grouse Population: Implications for Future Translocations

Duvuvuei, Orrin V. 01 May 2013 (has links)
Translocations have been used as a management strategy to successfully augment declining native wildlife populations. Greater sage-grouse (Centrocercus urophasianus; sage-grouse) population declines on Anthro Mountain, Utah prompted managers to translocate sage-grouse and test protocols from a successful translocation project in Strawberry Valley, Utah. Sage-grouse from Parker Mountain, Utah were used as the source population for Anthro Mountain and Strawberry Valley translocations. Sixty hens were translocated to Anthro Mountain in 2009 and 2010; I monitored vital rates of the 60 translocated hens and 32 resident hens from 2009-2012. My objective was to determine the overall success of the translocation 4 years after the initial release and compare vital rates to the source population and Strawberry Valley.In Chapter 2, I determined that survival varied by study area and hen age but was not affected by residency status. Annual survival of Anthro Mountain hens was lower than Parker Mountain and Strawberry Valley hens. Adult hen survival in all three populations was higher than yearling survival.In Chapter 3, I determined that the translocation contributed to population growth. Adult resident and previously translocated hens had the highest reproductive success, followed by resident yearlings, newly translocated adults, and newly translocated yearlings. Lek counts increased from 2009-2013 and a new lek was discovered in 2011. Survival was not affected by residency status or age, but varied greatly by year and season. Mean monthly survival was lowest in the fall; this differs from range-wide trends.In Chapter 4, I determined that translocated hens adapted to the release area. They exhibited similar seasonal movements and used similar habitats as residents. The home range size of resident and translocated hens was comparable; however, previously translocated hens had smaller home ranges than newly released hens.Despite landscape level differences between the source and release areas, translocated hens assimilated to the population and contributed to population growth. Although the translocation was successful, the low vital rate estimates are cause for concern. The low estimates suggest that factors such as predation, habitat quality and quantity, and anthropogenic influences may be problematic for this isolated population.
4

Investigation des fonctions de la protéine du pore nucléaire TPR en utilisant la microscopie à molécule unique

Bop, Bineta 08 1900 (has links)
Le complexe de pores nucléaires est le seul point d'entrée et de sortie du transport nucléocytoplasmique. Le panier nucléaire, l'un de ses principaux composants, s'est avéré impliqué dans la régulation des gènes et pourrait jouer un rôle majeur dans le contrôle de la qualité de l'export d'ARNm. Cependant, on sait peu de choses sur le fonctionnement du panier dans l'export nucléaire et la régulation des gènes. La principale composante structurelle du panier, la TPR (Translocated Promoter Region), est considérée comme l'acteur principal de la fonction de contrôle de la qualité du panier. Il reste à établir par quel mécanisme cette protéine assure la sélection des mRNP compétentes pour l'exportation. Malgré son implication connue dans le contrôle de la qualité des mRNP, l'exportation et la maturation, des questions demeurent: que fait vraiment le panier, qu'est-ce qui définit le contrôle qualité, comment le panier nucléaire est-il capable d'identifier l'ARN qui n'est pas compétent pour l'exportation et quels sont les rôles de différentes protéines composant le panier nucléaire. Récemment, il a été montré que la protéine TPR est présente dans deux populations, l'une dans le nucléoplasme et l'autre liée au NPC. Nos études préliminaires utilisant FRAP (Fluorescence Recorvery After Photobleaching) et la microscopie à molécule unique montrent que les molécules nucléoplasmiques de TPR ne sont pas impliquées dans un échange rapide avec les molécules assemblant avec les paniers ancrés au NPC et présentent différentes sous-populations basées sur la diffusion. L'analyse de études protéomiques préliminaires de notre laboratoire a révélé que l’interactome de TPR présente un enrichissement inattendu en protéines impliquées dans la maturation de l'ARNm, notamment l'épissage et les facteurs de traitement de l'extrémité 3'. Ces résultats pourraient suggérer des interactions complexes des nouvelles fractions nucléoplasmiques de TPR avec la machinerie de maturation des ARNms et nous amènent à poser les questions suivantes : Quelle est la fonction de la protéine du panier TPR lorsqu'elle n'est pas associée au NPC, et la TPR nucléoplasmique participe-t-elle au métabolisme de l'ARN nucléaire, reliant potentiellement les processus nucléaires au contrôle de la qualité au NPC? Mon projet s'est concentré sur l'étude des fonctions et de la dynamique de la protéine du panier nucléaire TPR à l'aide de techniques d'imagerie fluorescente en cellule vivante et de suivi de protéine unique. Nous avons pu identifier la dynamique et la localisation des différentes populations de TPR à partir des profils de diffusion de leurs trajectoires, qui peuvent être réparties en 5 catégories : Dirigée, Brownienne, Restreinte, Confinée et Butterfly. Nos données suggèrent que les trajectoires confinées pourraient être liée à l’association de TPR à la chromatine tandis que les browniennes représenteraient les molécules de TPR diffusant librement dans le noyau. De plus, nous avons constaté que les trajectoires dirigées et restreintes pourraient être liées à la maturation de l'ARN vu que ces deux sous-populations de TPR sont les plus affectées lorsque la transcription est inhibée. Également, en absence de la transcription par l’ARN polymérase II, TPR forme des granules dans le nucléoplasme, suggérant son implication durant la transcription active. Ainsi, notre étude montre que la fraction nucléoplasmique du TPR est subdivisée en fractions non associées aux pores hétérogènes qui pourraient jouer plusieurs rôles dans le métabolisme de l'ARN et la qualité de l'export. / The nuclear pore complex is the only entry and exit point for the nucleocytoplasmic transport. The nuclear basket, one of its main components, was shown to be involved in gene regulation and could play a major role in quality control of mRNA export. However, little is known on how the basket functions in nuclear export and gene regulation. The main structural component of the basket, TPR (Translocated Promoter Region), is thought to be the main actor in the quality control function of the basket. It is yet to be establish by which mechanism this protein ensures the selection of competent mRNPs for export. With all these involvement of the basket in quality control, export, and maturation, one question remains: What is the basket really doing, what defines quality control, how the nuclear basket can identify RNAs that aren’t competent for export, and what are the roles of the different proteins that make up the basket. Recently it was shown that TPR is present in two populations, one in the nucleoplasm and another bound at the NPC. Our preliminary studies using FRAP (Fluorescence Recovery After Photobleaching) and single molecule microscopy shows that the nucleoplasmic TPR molecules aren’t exchanging with the baskets anchored at the NPC and present different subpopulations based on diffusion. Analysis of preliminary proteomics studies from our laboratory revealed an interactome with an unexpected enrichment of proteins involved in mRNA maturation notably splicing and 3’ end processing factors. These results imply complex interactions of the new fractions of TPR and lead us to ask these following questions: What is the function of the basket protein TPR when it is not associated with the NPC, and does nucleoplasmic TPR participate in nuclear RNA metabolism, potentially linking nuclear processes to quality control at the NPC? My project focused on investigating the functions and dynamics of the nuclear basket protein TPR using fluorescent live-cell and single-protein imaging techniques. We were able to identify the dynamics and localization of the different populations of TPR based on the diffusion profiles of their trajectories, which can be divided in 5 categories: Directed, Brownian, Restricted, Confined and Butterfly. Our data suggest that the confined population might be linked to chromatin association of TPR, whereas the Brownian would represent the free diffusing TPR molecules in the nucleus. We further found that the Directed and Restricted trajectories could be linked to RNA maturation as these two subpopulations of TPR are most affected when transcription is inhibited. Moreover, in absence of transcription, TPR forms granules in the nucleus, suggesting its implication during active transcription. Altogether, our study shows that the nucleoplasmic fraction of TPR is subdivided in heterogenous diffusive fractions that could play several roles in the metabolism of RNA and quality of export
5

Investigating the Effects of Mutant FUS on Stress Response in Amyotrophic Lateral Sclerosis: A Thesis

Kaushansky, Laura J. 14 August 2015 (has links)
During stress, eukaryotes regulate protein synthesis in part through formation of cytoplasmic, non-membrane-bound complexes called stress granules (SGs). SGs transiently store signaling proteins and stalled translational complexes in response to stress stimuli (e.g. oxidative insult, DNA damage, temperature shifts and ER dysfunction). The functional outcome of SGs is proper translational regulation and signaling, allowing cells to overcome stress. The fatal motor neuron disease Amyotrophic Lateral Sclerosis (ALS) develops in an age-related manner and is marked by progressive neuronal death, with cytoplasmic protein aggregation, excitotoxicity and increased oxidative stress as major hallmarks. Fused in Sarcoma/Translocated in Liposarcoma (FUS) is an RNA-binding protein mutated in ALS with roles in RNA and DNA processing. Most ALS-associated FUS mutations cause FUS to aberrantly localize in the cytoplasm due to a disruption in the nuclear localization sequence. Intriguingly, pathological inclusions in human FUSALS cases contain aggregated FUS as well as several SG-associated proteins. Further, cytoplasmic mutant FUS incorporates into SGs, which increases SG volume and number, delays SG assembly, accelerates SG disassembly, and alters SG dynamics. I posit that mutant FUS association with stress granules is a toxic gain-of-function in ALS that alters the function of SGs by interaction with SG components. Here, I show that mutant FUS incorporates in to SGs via its Cterminal RGG motifs, the methylation of which is not required for this localization. Further, I identify protein interactions specific to full-length mutant FUS under stress conditions that are potentially capable of interacting with FUS in SGs. Finally, I demonstrate a potential change in the protein composition of SGs upon incorporation of mutant FUS. These findings advance the field of ALS and SG biology, thereby providing groundwork for future investigation.

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