Techn. University, Diss., 2005--Dresden.

Ability to regenerate is found in many groups of metazoans but the majority of research is focused on adults from just a few taxa, such as planarians and hydra (Agata and Inoue, 2012; Bely et al., 2014). Increasing the diversity of study organisms and life stages can reveal new and interesting aspects of regeneration mechanisms. This study focuses on regeneration of the nemertean pilidium larva. The planktotrophic pilidium of Maculaura alaskensis provides a unique model in which to observe several components of the regeneration process. Here I have documented a timeline for regeneration and have begun to evaluate the cells responsible for regenerative success. This study has revealed the interplay between regeneration and degeneration, a tradeoff between larval and juvenile structures, as well as the important relationship between global versus local signaling in proliferation and differentiation responses.

This reflexive ethnography investigates both the practice of cultural regeneration movement and fieldwork engagement in the context of contested development. The setting is Mt. Apo National Park where the Philippine National Oil Company has built a 250-megawatt geothermal power plant. The project aims to reduce government's dependence on imported oil and fuel its industrialisation program. Mt. Apo, however, is an ecologically and politically sensitive site, being a sanctuary of Southeast Asia's rich biodiversity, home to indigenous peoples, and shelter for armed insurgents. The local NGO and Church opposition grew into a massive national and international protest. Despite the hesitant hospitality of the affected community, PNOC managed to transform its image into a corporate environmentalist and pursue its project. This thesis explores the interaction among the various contextual actors, including social scientists and the sick, the pastors, priests and protesters. It also analyses the politicisation of rituals and the construction of advocacy in Europe. My main focus, however, is the kin-based movement called Tuddok. Tuddok aimed at cultural regeneration and territorial recognition. It emerged, apparently, from the failure of both development project and political protest to take seriously the predicament of the host community. Cultural politics research rightly treats this type of movement not simply as resistance, but as struggle for meaning and existence. Even recent literature, however, still equates movement with protest. I highlight, instead, what may be called cultural energies-the human capabilities by which people collectively re-animate themselves in face of, but not exhaustively in reaction to, political binary oppositions. My fieldwork (September 1995-January 1997) consisted mostly in accompanying Tuddok from its revival of Manobo dance, to its retrieval of Mt. Apo history and territory. As Tuddok became central to my research, my research in turn served as resource for the movement. This partnership grew tense as the ethnographer's status as Catholic priest allegedly threatened the peace of the Protestant village. The last section of the thesis reflects on the practice of fieldwork as social intervention before it is transformed into a textual invention.

Parkid higlohosa, an important indigenous fruit tree of West Affican Sudanian woodland, was studied with respect to natural population distribution and structure, regeneration, reproductive biology and phytosociology in Nigeria. As relevant background, a comprehensive range-wide monographic account of the species was assembled. An ecological survey covering the range of Parkia in Nigeria was undertaken between 1994-1995. The survey involved four ecological zones ranging from derived to Sudan/Sahel zone transition. In each ecological zone there were two sample sites within each of which there were two land use types. The survey showed that nearest mature con-specific neighbour distance and corresponding stocking for all individuals ý: 10 cm dbh ranged from 25.5 m and 15 tree ha-I in the north down to 91.5 m and I tree ha-I in the south. A gradual increase in stocking from the lowland forest zone boundary to the Sudan savanna was observed. Parkia populations are significantly more concentrated in cultivated fields than in less intensively used areas of the bush fallow. Natural regeneration in Parkia in Nigeria was sparse overall - 9.80 individuals ha-I and coppice shoot regeneration was the main form. Bush fallow conditions favour more regeneration than intense cultivation, and to the south there is more regeneration than in the north. Tree morphological appraisal showed that there tended to be taller trees in the south of the Nigerian range (with a moister climate) but with smaller diameter than in the north. A broader crown diameter typified populations in the northern part of Nigeria range compared with the south. Branching height ranged from 1.7 m in the north to 3.9 m in the south. The tree rarely branched below Im anywhere. Two was the most frequent number of primary branches. Individuals with more than two primary branches per tree occur more frequently in the north of the range. For all morphological parameters except the number of primary branches a significant land use effect was detected. In the survey 136 associated woody species were recorded. More woody tree species were associated with Parkia biglobosa in the south than in the north of its range in Nigeria. A reproductive cycle of 135 days was observed at Saki, Nigeria. Capitulum abortion rate was more than 30% and not related to the tree diameter or crown position. Capitulum, podding efficiency was about 67%. Open pollinated capitula had the highest number of pods per treatment. Parkid displays some degree of self-compatibility. Capitula located >5 m above the ground are more likely to be pollinated than those below.

Pannexin 1 (Panx1) and Pannexin 3 (Panx3) are single membrane channels recently implicated in myogenic commitment, as well as myoblast proliferation and differentiation in vitro. However, their expression patterns during skeletal muscle development and regeneration have yet to be investigated. Here, I show that Panx1 levels increase during development, becoming highly expressed in adult skeletal muscle. A switch in Panx3 expression pattern was observed as its ~70 kDa immunoreactive species was mainly expressed in embryonal and neonatal muscles while its ~40 kDa species was the main form expressed in adult skeletal muscle. In adult mice, Panx1 and Panx3 were differentially expressed in fast- and slow-twitch muscles. Interestingly, Panx1 and Panx3 levels were modulated in muscle degeneration/regeneration, similar to the pattern seen during skeletal muscle development. Since Duchenne muscular dystrophy is characterized by skeletal muscle degeneration and impaired regeneration, I next used mild and severe mouse models of this disease and found a significant down-regulation of both Panx1 and the lower MM form of Panx3 in dystrophic skeletal muscles, with an increase in the ~70 kDa immunoreactive species of Panx3. I also found that Panx1/PANX1 and Panx3/PANX3 are co-expressed in mouse and human satellite cells, which play crucial roles in skeletal muscle regeneration. Indeed, in vitro PANX1 levels may be increasing during human primary satellite cell differentiation and blocking PANX1 channel activity with the pharmacological compounds probenecid or carbenoxolone inhibited the differentiation and fusion of these satellite cells into myotubes. In addition, satellite cell proliferation was inhibited by probenecid and carbenoxolone. These findings are the first to demonstrate that Panx1 and Panx3 are differentially expressed amongst skeletal muscle types with their levels being highly modulated during skeletal muscle development, regeneration and dystrophy. In addition to our laboratory’s previous reports, I now demonstrate that PANX1 levels may be modulated during satellite cell differentiation and that PANX1 channels regulate satellite cell differentiation and proliferation. Altogether, my studies suggest that Panx1/PANX1 and Panx3/PANX3 channels may play important and distinct roles in myoblasts and satellite cells in healthy and diseased skeletal muscles.

In order to address ground and industrial water pollution, the University of Manchester has developed a novel and economic water treatment technology called the Arvia® process. This technology is being commercialized through a spin-out company, Arvia Technology Ltd. This process consists of adsorption and electrochemical regeneration in a single unit and can be carried out in batch or continuous modes where both operations can run simultaneously. This process has been successfully demonstrated for the removal and destruction of a number of organic contaminants using a graphite based adsorbent known as Nyex®1000. Nyex®1000 is an intercalation compound prepared from Chinese natural large fake graphite. This adsorbent has been found to be capable of fast adsorption and quick electrochemical regeneration in minutes due to its non-porous surface and high electrical conductivity. However, Nyex®1000 has a small adsorptive capacity for a number of organic pollutants and there is thus a need to develop new adsorbents with the aim of achieving high adsorptive capacity with maintaining good electrical conductivity. In this context, three routes for the development of adsorbents were selected, adsorbents developed through electrochemical intercalation, adsorbent developed through thermal and mechanical treatment of GIC-bisulphate and adsorbents developed through the formulation of composite materials. In order to strengthen the contributing effect of surface treatment, all raw graphite materials and developed adsorbents were characterized using Boehm titration, X-ray EDS, zeta potential, powder XRD, SEM, BET surface area, pore volume, particle size and bulk density techniques. These adsorbents were tested for the removal of a number of different target organic pollutants such as acid violet 17, mercaptans, phenol and humic acid using the Arvia® process. The performance of the developed materials was compared with the current adsorbent used in the Arvia® process i.e. Nyex®1000. A range of graphite types (synthetic graphite, Chinese natural large fake gra- phite, Madagascan medium fake graphite, natural vein graphite and recycled Abstract 27 vein graphite) were tested for the removal of acid violet 17 before and after electrochemical treatment in order to investigate the selection of the graphite types for the Arvia® process. The electrochemical surface treatment improved the adsorptive capacity by a factor of two for most of the graphite types tested and changed the surface of the graphite from hydrophobic to hydrophilic. Results obtained through surface characterization using Boehm titration, X-ray (EDS) elemental analysis and zeta potential measurements revealed a significant increase in oxygen containing surface functional groups on the surface of CNLFG in consequence of electrochemical surface treatment. The second type of adsorbent was developed through thermal and mechanical treatment of GIC bisulphate. It was tested for the removal of acid violet 17, mercaptans (ethane thiol & methyl propane thiol), phenol and humic acid using the Arvia® process. This material had twice the electrical conductivity of Nyex® 1000 and improved the adsorptive capacity by a factor of three for acid violet 17, approximately seven to eight for ethane thiol and methyl propane thiol, seven for phenol and two for humic acid. Starting and developed adsorbent materials were characterized using above mentioned techniques. The third type of adsorbent materials, three composite adsorbents were developed using high shear (wet) and compaction (dry) granulation methods. The composite adsorbent made through high shear wet granulation was found to have poor mechanical strength. The second and third composite adsorbents were developed through dry compaction granulation using carbon black, synthetic graphite and exfoliated graphite as raw materials. These adsorbents delivered improved adsorptive capacity for acid violet 17 by a factor of 100 and 9 respectively. Electrochemical regeneration efficiencies of around 100 % were obtained for these adsorbent materials. However, electrochemical parameters required to achieve 100 % regeneration, such as current density and regeneration time were found to vary depending on the adsorptive capacity of each adsorbent material for a particular polluting agent.

Abstract Angiogenesis is essential for the replacement of cartilage by bone during skeletal growth and regeneration. Vascular endothelial growth factor-A (VEGF-A) is a key regulator of angiogenesis whereas endostatin, a potent inhibitor of endothelial cell proliferation and migration, is a natural antagonist of VEGF-A. The regulatory roles of these peptides in angiogenesis, bone formation and bone cells were investigated in this study. In the present work we studied the effects of VEGF-A, delivered with an adenoviral vector, on the recovery of bone drilling defects in rat femur. Our data confirm the important role of VEGF in bone healing and that adenoviral VEGF gene transfer may modify bone defect healing in a rodent model. We studied the effects of VEGF-A and endostatin on bone resorption activity. It was found that VEGF-A is a potent stimulator of bone resorption and osteoclast differentiation in vitro and endostatin can antagonize this stimulatory effect when acting directly on bone cells. This suggests that endostatin is indeed a regulator of bone resorption, but not a critical one. In the present study we induced ectopic bone formation in the hamstring muscles of adult mice. The effects of VEGF-A and endostatin in the ectopic bone formation assay were evaluated by the simultaneous delivery of both peptides with recombinant adenoviral vectors. It was found that endostatin retards the cartilage phase in endochondral ossification that subsequently reduces bone formation. We conclude that bone growth and healing, which share features with ectopic bone formation, may be regulated by endostatin. To confirm in vivo effects on bone formation we further investigated the effects of endostatin and VEGF-A on mouse pre-osteoblastic cells in vitro. Finally the effects of endostatin on bone were studied in transgenic mouse lines overexpressing endostatin, and mice lacking collagen XVIII.

Newts, such as Notophthalmus viridescens, can regenerate many structures after amputation or injury and have also shown a refractory response to the formation of cancer in tissues that have regenerative capabilities. The mechanisms behind this latter ability have surprisingly not been studied. In the current study, N. viridescens were exposed to a variety of carcinogens in tissue that cannot regenerate with the intention of inducing tumour formation. After testing multiple carcinogens, multiple sites of injection, and two different modes of delivery, no tumours were generated. Consequently, in vitro assays were developed in order to better understand this ability of newt cells to evade transformation. Mouse and newt muscle cells were exposed to DNA damaging agents, such as irradiation and carcinogens, in culture and their response was monitored with respect to the DNA damage response proteins γ-H2AX, p53, and phospho-p53. These proteins are important as they help prevent mutations in the genome from being passed on to daughter cells and potentially generating cells that proliferate uncontrollably, a hallmark of cancer. Preliminary results suggest that after irradiation, γ-H2AX is present in newt cells for a considerably longer period of time in comparison to mouse cells. p53, as well as phospho-p53, appear to be present at a basal level before and after irradiation in newt cells, whereas mouse cells have a distinct increase upon damage and decrease upon repair. The carcinogen treatments also suggest that newt cells have basal levels of expression of these proteins prior to treatment. These studies suggest that newt cells may have a unique profile of these DNA damage response proteins and may be “primed” to repair any future damage. This is a good first step in understanding what is likely a very complicated explanation for newts’ refractory response to cancer formation.

This thesis describes my study of inhibition of brain regeneration in planaria. The flatworm (Dugesia tigrina) possesses a remarkable ability to regenerate lost parts, including the head. The primary objective of my study was to determine the extent to which an inhibiting substance, located in the head, would prevent regeneration of the brain. A secondary objective was to study whether DMSO (Dimethyl Sulfoxide) would facilitate the action of the inhibitor.

Direct in vivo cellular reprogramming offers the potential for local neural replacement to promote post-stroke neural regeneration and recovery. Pericytes are perivascular cells involved in blood-brain barrier maintenance under physiological conditions but are reprogrammed into multipotent induced neural progenitor cells (i-NPCs) in response to ischemia. The atypical protein kinase C (aPKC)-CREB binding protein (CBP) pathway regulates ischemia-activated pericyte (a-pericyte) reprogramming and neuronal differentiation. Our previous work showed that the pathway inhibitor compound C (CpdC) facilitated a- pericyte reprogramming into i-NPCs in culture, and that monoacylglycerol lipase (Mgll) inhibitor JZL184 was able to promote NPC differentiation to generate newborn neurons by mimicking pathway activation. In this regard, we propose to use acute CpdC treatment followed by chronic JZL184 treatment to enhance reprogramming of a-pericytes into i-NPCs and subsequently promote their neuronal differentiation, ultimately improving post-stroke functional recovery. Using the endothelin-1 (ET-1)/L-NAME ischemic stroke model in a pericyte lineage tracing transgenic mouse line, I characterized the ability of a-pericytes in the ischemic lesion site to generate neural (i-NPC, newborn neurons) and non-neural (microglia and fibroblasts) cell types. The CpdC+JZL184 treatment had early effects on enhancing a- pericyte reprogramming efficiency to produce i-NPCs at 7 days post-stroke and promoting their differentiation to generate neuroblasts at 14 days post-stroke. However, it did not affect stroke volume and produced minimal alterations to the pattern of post-stroke motor function recovery. Interestingly, I discovered a novel role of tamoxifen treatment prior to stroke in regulating reprogramming of a-pericytes and efficacy of compound C treatment. These studies inform the necessity of optimization of drug delivery for better control over the timing and duration to directly target in vivo i-NPC reprogramming and reveal a novel pharmacological paradigm to control the aPKC-CBP pathway.