A central tenet of stem cell biology has been that proliferating tissues are maintained through a cellular hierarchy comprising of self-renewing stem cells at the apex, multiple lineage-restricted short-lived progenitor cells, and post-mitotic differentiated cells. The wide range of colony sizes in cultured human keratinocytes has been taken to support this hypothesis. Contrary to this model, researchers using genetic lineage tracing in mouse epidermis have inferred a single progenitor population for homeostasis, and a quiescent stem cell population activated upon wounding or genetic mutation. To study the proliferative behaviour of human keratinocytes, I used live imaging in vitro at single cell resolution. This shows two modes of proliferation: Type 1 cell division is stochastic with equal odds of generating dividing or non-dividing progeny, while Type 2 cell division predominantly produces two dividing daughters. These two modes are sufficient to explain the entire range of colony sizes seen after 7-12 days of culture and does not require a spectrum of proliferative ability. This insight provides a simple way to study the effects of external factors on cell fate. To exemplify this, I observed the effects of epidermal growth factor (EGF) and the Wnt agonist R-spondin on proliferation. Here I find proliferation in type 2 colonies changes by changing the proportion of cells dividing. This has implications for the limited success of EGF therapies in clinical trials following burns. To examine clonal contributions to wound repair, I used the mouse oesophageal epithelium which is exclusively composed of, and maintained by, a single progenitor population. I developed a micro-endoscopic wounding technique that produced localised superficial wounds. Here, I found that these wounds healed by uniform contribution from surrounding keratinocytes, demonstrating that reserve stem cells are not obligatory for wound repair. In summary, my work shows that human keratinocytes in vitro have two, and only two, modes of proliferation: a stochastic mode that is insensitive to external EGF signalling, and a EGF-sensitive exponential mode. Additionally, proliferation during wound repair can occur with stochastically dividing progenitors, and does not obligate stem cell recruitment in vivo.

In addition to ATP generation, mitochondria are essential in various cellular processes ranging from biosynthetic pathways, apoptosis, cell cycle progression, and calcium buffering. Studies in living cells have now firmly established that mitochondria exist as a dynamic network sculpted by fission and fusion reactions, rather than separated, individual organelles. Not surprisingly, mutations in genes involved in mitochondrial dynamics and quality control lead to human diseases such as Charcot-Marie-Tooth disease type 2A, Optic atrophy, and autosomal recessive Parkinson disease. I have designed a high-throughput protocol to permit genome-wide screening for novel genes that are required for normal mitochondrial morphology. I have executed a genome-wide RNA interference screen and identified several novel genes required for mitochondrial dynamics in addition to known regulators of mitochondrial dynamics. A detailed high-throughput genome-wide screening protocol is presented. I have shown that TID1, a gene identified from the screen, has a dual-role in maintaining the integrity of mitochondrial DNA and preventing the aggregation of complex I subunits. My analysis of the mitochondrial role of TID1 supports the existence of a TID1- mediated stress response to ATP synthase inhibition. The genome screen also identified the novel gene ROMO1 as essential for normal mitochondrial morphology. I have shown that ROMO1 may have an additional role in maintaining mitochondrial spare respiratory capacity, possibly by affecting cellular substrate availability. Finally, in a collaborative effort, we have shown that homozygous mutations in the mitochondrial fusion gene MFN2 lead to multiple symmetric lipomatosis (MSL) associated with neuropathy. Mechanistically, this mutation reduces MFN2 homocomplex formation. Taken together, these results show the utility of genome-wide screening in identifying genes involved in mitochondrial quality control.

Over the years, phonologists working in the generative framework have encountered a number of persistent problems in their descriptions of Japanese phonology. Several of these problems concern phonological rules that sometimes do and sometimes do not apply in seemingly identical phonological environments. Many of the proposed analyses achieve observational adequacy, but, nonetheless, are intuitively dissatisfying. The first of two such problems involves the desiderative suffix -ta and the homophonous perfective inflection -ta, both of which attach to verb roots. When the verb root is vowel-final, the derivations are straightforward. (1) (a) tabe + ta + i → tabe-ta-i 'want to eat' mi + ta + i → mi-ta-i 'want to see' (b) tabe + ta → tabe-ta 'ate' mi + ta → mi-ta 'see (past)' Derivations are not so straightforward when the verb root is consonant-final. In such cases an intervening i is inserted between the root and the desiderative suffix, but not between the root and the perfective inflection. (2) (a) tat + ta + i → tat-i-ta-i 'want to stand' kat + ta + i → kat-i-ta-i 'want to win' (b) tat + ta → tat-ta 'stood' kat + ta → kat-ta 'won' McCawley (1968) is not specific in how he accounts for this differential it appears that he favours the adoption of a morphological rule such as (3) (from Koo, 1974). (3) ∅ → i / C]v__+tai Koo (1974) has attempted to reanalyze the desiderative suffix as -ita, but, since there is no evidence of W cluster simplification in the language, he is left with the even more difficult problem of deleting the initial i of the suffix following vowel-final verb roots. (4) tabe + ita + i → tabe-ta-i 'want to eat' mi + ita + i → mi-ta-i 'want to see' Maeda (1979) has chosen a boundary solution, positing that t-initial inflections are joined to verb roots by morpheme boundaries (+), while other suffixes such as the desiderative suffix are joined by a stronger boundary (:). By making the i insertion rule sensitive to boundaries of level :, the correct outputs can be derived. This solution, though, is unsatisfactory since the assignment of boundaries is not independently motivated. A second difficulty encountered by McCawley (1968) and others involves a high vowel syncopation rule that deletes the final i or u of Sino-Japanese monomorphemes when the initial consonant of a following Sino-Japanese monomorpheme is voiceless. (5) iti + too → it-too 'first class' roku + ka → rok-ka 'sixth lesson' However, a morpheme- or word-final high vowel at the boundary between a Sino-Japanese compound and a Sino-Japanese monomorpheme does not delete under those conditions insertion of i in these phonological identical environments, but (6) zi-ryoku 'magnetism' (X-Y) zi-ryoku + kei → zi-ryoku-kei 'magnetometer' (X-Y-Z) hai-tatu 'delivery' (Y-Z) betu + hai-tatu → betu-hai-tatu 'special delivery' (X-Y-Z) McCawley accounts for this pattern by invoking internal boundaries of different strengths: + and #. (7) iti + too roku + ka zi + ryoku # kei betu # hai + tatu He claims, then, that high vowel syncopation is sensitive to boundaries of strength + and is, therefore, blocked from applying to the u of zi + ryoku # kei. His analysis is correct, but his assignment of boundary strengths is rather arbitrary. Analyses such as the two above which appeal to boundary strength hierarchies have often been intuitively dissatisfying because of a lack of independent motivation. The relatively recent theory of lexical morphology and phonology as formulated by Kiparsky (1982) is ideally suited for this type of problem. One of the theory's most compelling attributes is that phonological processes may be put into a much broader context that includes morphological processes as well. This more integrated approach is often able to fit formerly isolated facts into a network of related facts to provide compelling independent motivation for diverse processes. The purpose of this thesis, then, is to fit i insertion, high vowel syncopation, and other Japanese phonological processes into the lexical phonology network to see exactly how they are related to each other and to the morphological phenomena of the language. / Arts, Faculty of / Linguistics, Department of / Graduate

This thesis provides an analysis of wh-questions in Nêhiyawêwin (Plains Cree). The study is done within the Principles and Parameters framework (Chomsky 1981, 1986, 1995). I argue that Nêhiyawêwin wh-words like awfna 'who' are not generated in argument position and do not undergo A-bar movement to Spec CP (Chapter 3). Rather, they are licensed as the predicate of a nominal clause, and respect the same syntactic constraints as other nominal clauses: they are strictly predicatê-initial; obey a referentiality hierarchy; and display agreement for number, animacy and obviation (chapter 4). I analyze Nêhiyawêwin nominal clauses as IP with a null Infl head in which the predicate fronts to Spec CP. The clausê-initial position of the wh-word is thus part of a more general process of predicatefronting. The nominal clause analysis of wh-words accounts for the absence of wh-movement per se in the language, as well as for the absence of wh in situ. However, based on their interpretive properties, wh-questions must contain an operator-variable chain. I argue that the operator-variable relation arises when the subject of the nominal clause links to an A-position in a subordinate clause. This occurs in one of two ways: by means of the kâ-complementizer or the ê-complementizer (Chapter 5). If the subordinate clause has kâ-, the resulting structure is a relative clause which restricts the reference of the subject. This yields a cleft construction: Who is it[sub i] that Mary likes t[sub i] ? If the subordinate clause has ê-, the clauses are conjoined, and null-operator movement in the subordinate clause forces an anaphoric relation between the wh-word and the A-position in the ê- clause: Who is he[sub i] & OP[sub i] Mary likes him[sub i]. Having shown how Nêhiyawêwin wh-words are associated with an operator-variable chain, I then consider the consequences of the proposed analysis (Chapter 6). A defining property of wh-chains is their sensitivity to island effects. Consistent with this, there is an argument/adjunct asymmetry in Nêhiyawêwin, which in turn bears on the question of where overt arguments are positioned in a polysynthetic language. I argue that complement clauses are basê-generated in an A-position, unlike overt DPs which are in an A'-position (adjoined to IP). This explains why long-distance extraction is possible from complement clauses, while extraction from adjunct clauses is ungrammatical. Another property of wh-chains is their sensitivity to Weak Crossover (WCO). WCO effects are absent in Nêhiyawêwin wh-questions. I argue that WCO may be avoided because there is no movement of a truly quantificational operator in the sense of Lasnik and Stowell (1991), but rather movement of a null operator. I then propose a Weakest Crossover analysis for the absence of WCO, following Demirdache (1997). / Arts, Faculty of / Linguistics, Department of / Graduate

The goal of this thesis is to present an analysis of verbal plurality and adverbial quantification in Skwxwu7mesh (Squamish Salish). This thesis provides a detailed analysis of a phenomenon in Skwxwu7mesh that has never been explored: the effect of the auxiliary wa on predicates from various aspectual classes in both non-quantified and quantified sentences, wa has been described as a morpheme referring to a process that has duration either in the form of a single act or the regular performance of it (Kuipers 1967). Two central questions will be addressed in this thesis. Firstly, what is the function of the auxiliary wa in Skwxwu7mesh?. In other words, why is wa obligatorily present for certain interpretations of predicates and obligatorily absent for others; furthermore, what does wa do to a predicate to yield the various readings? Secondly, why is wa obligatory with adverbs of quantification? To answer these questions, this thesis proposes that wa is a pluractional marker that pluralizes the head of a predicate's event structure or the event type denoted by the predicate. Assuming Pustejovsky's (1991, 1995) event structure model representing the distinction between three primitive event types (states, processes, transitions), four aspectual classes are analyzed (activities , accomplishments , achievements and states) in both English and Skwxwu7mesh. This thesis argues that Skwxwu7mesh provides crucial evidence that all bare predicates (that is, predicates without wa) are telic, with the exception of individual-level predicates, wa causes a predicate to be atelic via pluralization; this atelicity is marked by continuous and/or habitual readings for the predicates of the various classes. As a consequence of these claims, this analysis suggests that activities and stage-level states are not primitives universally. This thesis argues that Kratzer's (1995) analysis of adverbs of quantification as unselective binders cannot account for Skwxwu7mesh; thus, adopting De Swart's (1993, 1995) event based approach to analyzing adverbial quantification, this thesis claims that Skwxwu7mesh provides crucial evidence that Q-adverbs quantify over events only. The evidence derives from the fact that the pluractional marker wa is obligatory with both stage-level stative predicates and individual-level predicates when they combine with a Q-adverb. The analysis presented in this thesis claims that wa is the source of the plurality of events over which a Q-adverb quantifies. / Arts, Faculty of / Linguistics, Department of / Graduate

Orientadores: Luis Felipe de Toledo Ramos Pereira, Renato Neves Feio / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-27T16:33:55Z (GMT). No. of bitstreams: 1 Nunes-de-Almeida_CarlosHenriqueLuz_M.pdf: 2724728 bytes, checksum: 32daa352df879ffab82840075e1dc3f6 (MD5) Previous issue date: 2015 / Resumo: Os anfíbios da família Cycloramphidae são endêmicos da porção oriental do Brasil e alguns estão ameaçados ou em perigo de extinção. Apesar de ser uma família com poucos grupos taxonômicos, apenas três gêneros (Cycloramphus, Thoropa e Zachaenus), até o momento não há uma proposta filogenética para o gênero Thoropa que abranja todas as espécies. Então, propomos a reconstrução filogenética de Thoropa usando como grupo esterno, uma espécie do gênero Hylodes (Hylodidae), duas do gênero Cycloramphus e uma espécie do gênero Zachaenus. Definimos 86 caracteres baseados em osteologia, ecologia e morfologia externa de adultos e larvas. Neste contexto realizamos a descrição da forma larval de Cycloramphus rhyakonastes, a qual foi utilizada como grupo esterno. A filogenia proposta é baseada em critérios de máxima parcimônia. Como duas das árvores resultantes indicam parafilia, propomos aqui um novo gênero para as espécies de menor porte, separando-as das espécies maiores / Abstract: The phylogenetic resolution of Neotropical amphibians increased considerably in recent decades, providing great understanding of the relationships of higher taxa, such as the relationships between families and genera. After such improvement, amphibian systemticians are now focusing their efforts on lower taxa, such as the relationships within congeneric species. Under such context we did a phylogenetic reconstruction of the genus Thoropa, for which no comprehensive phylogeny is available. We examined all species of the genus including two species with extinct populations and possible new species. We adopted the criteria of maximum parsimony to analyze 86 characters based on osteology, external morphology, behavior, bioacoustics, and tadpole external morphology of at least one specimen per species. As the resulting topology of Thoropa tree indicates a possible case of paraphyly, we propose a new genus, assuring the monophyly of Thoropa in all possible scenarios / Mestrado / Biodiversidade Animal / Mestre em Biologia Animal

A família Simaroubaceae constitui um grupo com grande potencial de estudo. Com distribuição essencialmente tropical, é considerado um grupo relativamente pequeno dentro da Ordem Sapindales e monofilético, mas morfologicamente diversificado. Apenas Engler, no final do século XIX, estudou detalhadamente a família no Brasil como um todo, e desde então as adições ao conhecimento do grupo têm ocorrido de forma gradual e fragmentada. Esta dissertação aborda estudos estruturais de espécies do gênero Simaba, o maior da família, analisando a estrutura foliolar dos representantes de todas as suas seções, Simaba sect. Floribundae Engl., S. sect. Grandiflorae Engl. e S. sect. Tenuiflorae Engl., a fim de selecionar caracteres morfológicos e anatômicos para auxiliar os trabalhos de taxonomia deste gênero, que não recebe tratamento desde uma revisão taxonômica publicada em 1983. Além do estudo das estruturas vegetativas, neste trabalho documentamos as estruturas florais, que possuem com poucos registros de estudo na literatura do grupo, por meio de análise comparativa da morfologia e anatomia das flores de espécies pertencentes às seções S. sect. Floribundae e S. Sect. Grandiflorae, tradicionalmente distintas principalmente pelo tamanho da flor e grau de fusão do apêndice estaminal ao longo do filete, mas com grande semelhança morfológica entre si. Além de apresentar as descrições e ilustrações das características estruturais vegetativas e reprodutivas encontradas, investigamos a existência de atributos florais ainda não reportados no grupo, provendo um panorama de caracteres foliares e florais informativos para subsidiar a resolução dos problemas taxonômicos existentes no gênero e visando melhor delimitação entre as espécies que exibem grande semelhança morfológica, mesmo pertencendo ao mesmo grupo. / The Simaroubaceae family is a group with great potential for study. With essentially tropical distribution, it is considered a relatively small group within the Order Sapindales and monophyletic, but morphologically diverse. Only Engler, in the late nineteenth century, studied in detail the family in Brazil, and since then the additions to the knowledge of the group have taken place gradually. This dissertation deals with structural studies on the largest genus of the family Simaba, analyzing the leaflet structure of representatives of all its sections, Simaba sect. Floribundae Engl., S. sect. Grandiflorae Engl. and S. sect. Tenuiflorae Engl., we select morphological and anatomical characters for this genus, which does not receive taxonomic treatment since 1983. In addition to the study of vegetative structures, we documented floral structures of selected Simaba species, which have few study records in the group\'s literature. Through a comparative analysis of the morphology and anatomy of flower, we studied species belonging to sections S. sect. Floribundae and S. sect. Grandiflorae, traditionally distinguished mainly by flower size and degree of fusion of stamen appendages, but with some morphological similarity. In addition to presenting the descriptions and illustrations of the vegetative and reproductive structural features, we investigate the existence of floral traits not yet reported for the group. We also provide an overview of informative leaf and floral characters that support the resolution of existing taxonomic problems in the genus and to assist delimitation among species.

I have collected a series of linear measurements of the postcranial skeletons of 43 extant crocodylian and lepidosaur taxa to determine if those engaging in similar locomotor behavior display similar morphology despite phylogenetic differences. Stepwise discriminant function analyses reveal reptile locomotor mode can be accurately predicted (over 80% correct) based on morphology. Semi-aquatic taxa are distinguished by a longer ischium relative to pubis length, a longer scapula relative to humerus length, and a broader acetabulum than terrestrial and arboreal taxa. Arboreal taxa display a more elongate, gracile humerus and a smaller acetabulum. This morphometric data can potentially be used to predict the locomotor behavior of a wide range of extinct reptile taxa. Within this study, Hyposaurus rogersii, Necrosuchus ionensis, Alligator sp. of the Gray Fossil Site, Crocodylus affinis, and Allognathosuchus mooki were examined and all were inferred to be semi-aquatic by the discriminant function analysis.

Thesis (M.Sc. (Chemistry)) -- University of Limpopo, 2015 / This dissertation investigated the properties of ferrierite synthesised using different SiO2 sources under identical conditions. The SiO2 sources used were TEOS, water-glass, Aerosil 200 and Ludox LS-30. The synthesis procedure comprised preparation of a gel with molar composition: 20 Na2O : Al2O3 : 37 pyrrolidine : 66:5 SiO2 : 6:3 H2SO4 : 1460 H2O. This was followed by hydrothermal treatment at 160 oC in a stainless steel autoclave for 72 h. The solid products were characterised by XRD, SEM, NH3-TPD and BET techniques. The ferrierite prepared using sodium silicate was more crystalline than ferrierite zeolites synthesised using Ludox LS-30, Aerosil 200 and tetraethyl orthosilicate as SiO2 sources. An amorphous phase was produced when ferrierite was synthesised using unhydrolysed TEOS as a sole SiO2 source. The physicochemical properties of the materials were not only affected by the nature of the SiO2 source, but also some synthesis manipulations such as acid-hydrolysis and water-glass addition when TEOS was used as a primary silica source. There were improvements in the materials produced when the TEOS was pre-hydrolysed with HCl and also mixed with water-glass in equal proportions. The SEM images of ferrierite materials synthesised using water-glass and Ludox LS-30 were uniform. The water-glass-based materials were thin sheets, flake-like images and Ludox LS-30-based produced thin-plate-like morphologies. The micrograph of ferrierite synthesised using TEOS as the SiO2 source showed hexagonal-type morphology and aggregates of smaller particles. There were two types of shapes in the ferrierite synthesised using Aerosil 200 as the silica source, namely, octagonal prismatic and hexagonal type morphologies. An equimolar mixture of TEOS and water-glass showed octagonal prismatic shape with triangular faces along certain edges of the material. The NH3-TPD acid site distribution profiles showed two peaks of weak acid strength at low temperatures (≤ 350 oC) for the representative H-ferrierite investigated. The ferrierite materials synthesised using unhydrolysed TEOS and Ludox LS-30 as SiO2 sources, showed NH3 desorption peaks at higher temperatures (≥ 350 oC). These peaks correspond to ammonia eluted from strong acid sites. The BET surface area of ferrierite synthesised using water-glass was high, while the material synthesised using unhydrolysed TEOS had the lowest surface area. Novel crystal shapes, comprising octagonal prisms with additional triangular phases, were observed in ferrierite samples prepared by the use of TEOS/water-glass mixture as silica source. The zeolitic materials prepared in this study were tested for the efficiency in the removal of Cu2+ from simulated wastewater, using a batch method. The effects of initial pH, initial concentration, contact time and adsorbent dose on Cu2+ adsorption were studied. All the materials showed maximum metal uptake efficiency at pH 5, and this pH was fixed in further studies involving other variables. It was observed that the metal uptake from aqueous solution increased with contact time and adsorbent dose. The Na-form of ferrierite synthesised using water-glass was the poorest Cu2+ adsorbent with respect to the four variables investigated (pH, contact time, adsorbent dose and initial metal ion concentration). KEY CONCEPTS Acidity, Adsorption, Ferrierite, Morphology, Silica source.

No description available.