We defined a new type of open Gromov-Witten invariants on hyperK\"aher manifolds with holomorphic / Mathematics

Plant cell walls play a central role in cell growth and morphogenesis. All plant cells have a primary wall. The formation of a secondary cell wall is restricted to particular cell types, such as the xylem cells, highly lignified cells that provide support and transport functions to the plant. The mechanisms regulating secondary cell wall biogenesis remain largely unknown. To identify genes involved in such mechanisms, a genetic screen for mutants with altered xylem development in the primary root of Arabidopsis thaliana has been conducted. Three different classes of mutants were identified. They are characterised by increased number of xylem strands (m"), altered timing of protoxylem differentiation (tpx) and ectopic lignification (eh). Initial characterisation of the mutant phenotypes, establishment of different complementation groups and their map position in the Arabidopsis genome has been determined. Mutations in the EL [I locus have been characterised in further detail. The eli l mutants exhibited ectopic lignification of cells throughout the plant that never normally lignify. Xylem cells in elil were misshapen and failed to differentiate into continuous strands, causing a disorganised xylem. elil mutants also exhibited altered cell expansion resulting in a stunted phenotype. Abnormal distribution of cellulose and lignin was observed in elil cell walls. Ultrastructural analysis of elil cell walls using an anti-lignin antibody has revealed that that the ectopic deposition of lignin-like compounds occurs within an altered secondary wall. Furthermore, other previously described cell expansion mutants, such as lit, rswl (at the conditional temperature) and det3, exhibited lignification patterns reminiscent to that of elil mutants. Analysis of the genetic interactions of elil with the lit mutant revealed that ELlI and LIT genes act in independent pathways to control cell expansion. These results, together with the double mutant analysis of eli l with other cell expansion mutants suggested a link between cell growth and differentiation of secondary thickened walls. Map-based cloning placed the ELJ1 gene in a 140-Kb interval on the top arm of Arabidopsis chromosome V. A candidate gene approach was used that identified a gene encoding a cellulose synthase catalytic subunit (CesA), AthCesA-3 as a candidate. Sequence analysis revealed that the AthCesA-3 gene is mutated in two elil alleles sequenced, both mutations leading to amino acid substitutions. Initial complementation experiments of elil plants with the wild type AthCesA-3 gene appeared to restore the wild type phenotype, suggesting that mutations in the AthCesA-3 gene gave rise to the elil phenotypes. These studies represent an important contribution to our understanding of the molecular mechanism of cellulose deposition during cell expansion and secondary cell wall deposition during plant morphogenesis.

Growth anisotropy, in which cells grow predominantly in one direction, is common in plant cells, and an essential event for plant form and function. The direction and degree of growth anisotropy are governed by the mechanical properties of the primary cell wall. When aligned in a parallel manner, cellulose microfibrils accommodate great resistance in the direction of their alignment to expansion driven by isotropic turgor pressure. Using the Arabidopsis thaliana inflorescence stem as a model system, field emission scanning electron microscopy (FESEM) analysis demonstrated that the establishment of parallel arrangement of microfibrils is closely correlated with anisotropic cell expansion. In the novel anisotropy 1 (any1) mutant allele of the primary cellulose synthase CesA1, growth defects were correlated with random cellulose microfibril patterns in some inflorescence stem tissues. Microtubules have been considered to be the most likely candidates for controlling the orientation of cellulose microfibrils. Recent studies have indeed demonstrated a close association of the plasma membrane-localized cellulose-synthase-complexes (CSCs) that produce cellulose and cortical microtubules. Despite this close association, microtubule disruption did not cause cellulose microfibrils to lose parallel alignment in the radial and inner periclinal walls of cells in the inflorescence stem, suggesting that microtubules influence mechanical properties of cellulose microfibrils other than orientation. X-ray diffraction analysis demonstrated that cellulose crystallinity in wild-type plants declines at the growth-promoting temperature of 29°C, whereas crystallinity fails to adapt and remains high in mor1-1, the temperature-sensitive mutant whose microtubule arrays become disorganized at its restrictive temperature (29°C). This finding suggests that organized microtubules are involved in reducing cellulose crystallinity that normally accompanies increased cell expansion. Live-cell imaging of CSCs by tracking a yellow fluorescent protein (YFP)-tagged CesA6 subunit in hypocotyl cells demonstrated that dynamic and well-organized microtubules affect the velocity, the direction of movement, and the density of CSCs, suggesting that there is a close relationship between microtubules and CSCs. Together with the finding that microtubules also control the distribution of COBRA, a GPI-anchored wall protein that is essential for growth anisotropy, I discuss the variety of roles microtubules play in anisotropic growth.

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The fall of the Berlin Wall on November 9, 1989 was called by many observers of international affairs the end of the Cold War. However, fifteen years earlier, commentators such as Alistair Buchan had also declared the end of the Cold War. Was this just an premature error on Buchan's part or is there a link between the events of the early 1970s, which is referred to as the era of detente and those leading up to the collapse of the Berlin Wall. It is the intention of this thesis to argue that these periods are integrally related mainly by the fact that they were each periods when one of the two superpowers was forced to reevaluate their foreign policies. The re-evaluations were brought about by changes in the international arena, most importantly a change in the nature of military power. Because the two superpowers were to recognize the change in the nature of military power at different times, it was not until both the United States and the Soviet Union had re-evaluated and altered their foreign policies was the Cold War really over. This thesis will firstly discuss the theoretical approaches to International Relations and the issue of power. It will then identify and define this change in the nature of military power by tracing the evolution of war and conflict in the past century. The thesis then trace the development of both US and Soviet foreign policy from the origin of the Cold War, through its various stages until the fall of the Berlin Wall. Through materials obtained from both US and Soviet archives, as well as interviews, this thesis will argue that this change in the nature of power was a central factor in altering the thinking of American and Soviet leaders at the time they brought drastic change to their foreign policies. Finally, this thesis will briefly look at the future role of military power as the world moves into the twenty-first century.

In this study I use semi-structured interviews and participant observation, in an intersectional and post-colonial theoretical framework, to look at one specific aspect of the Israeli occupation of the Palestinian territory: the restrictions of movement that are a result of the occupation, and how these influence different groups of the population in different ways, more specifically by analysing intersections of gender and age.  I consider not only restrictions caused by physical barriers, but also barriers caused by fear of violence or detainments and arrests. In the second part of the study I analyse strategies of resistance against the issues caused by the restrictions of movement and their gendered aspects. I show how the effects of the Wall, barriers and restrictions of movement are gendered and age-related, identifying multiple vulnerable locations at different intersections of gender and age. I also demonstrate how both individual strategies of resistance and the possibilities to participate in organised forms of resistance are gendered.

Glucans are polysaccharides integral to many materials and biological functions. Under the umbrella of Biomime, the Swedish Center for Biomimetic Fiber Engineering, this work has aimed to improve basic understanding of the biosynthesis of such glucans. This has been achieved through direct investigation of cellulose structure, and by developing the tools to analyze glucan biosynthesis. Notably we have identified a novel chemical effector of glucan synthesis processes and developed a proteomic toolkit useful for analyzing membrane-bound glycosyltransferases, the enzyme group responsible for glucan biosynthesis. During this work, glucan synthesis has been studied using both Gluconacetobacter and Populus cell suspension cultures. Publication I. Gluconacetobacter cellulose (BC) was used as a base to create a novel and well characterized nano-material with improved mechanical properties. This novel composite of BC and hydroxyethylcellulose (HEC) had improved tensile strength compared to pure BC. Through thorough study utilizing dispersion measurements, electron microscopy, nuclear magnetic resonance and X-ray diffraction it was shown that the improved properties derived from a layer of HEC coating each fibril. Publication II. Bacterial cellulose was labeled in specific positions with 13C (C4 and C6). These samples were analyzed by CP/MAS NMR along with cellulose samples from cotton and Halocynthia sp. For each sample spectral fitting was performed and general properties of crystal allomorph composition and fibril widths were determined. Calculations were also made for water accessible surfaces of the fibrils. The results showed that water accessible C4 surface signals are reflective of the allomorph composition of the sample, along with a distorted signal that derives due to fibril imperfections. Water accessible surface signals from the C6 region are instead derived from rotamer conformations of the C6 hydroxymethyl groupsfrom glucose residues. In Publication III, a high-throughput screen was used to identify an inhibitor of Golgi-derived glycosyltransferase activity, termed chemical A. The structural basis for inhibition was determined and in vitro assays of callose synthesis were performed. The in vitro assays revealed chemical A to also be an activator of callose synthesis. To understand this activation kinetic studies were performed, showing that chemical A is a mixed type of activator, which can bind either the free enzyme or the enzyme-substrate complex. Chemical A has uses in chemical genetics for dissecting processes involving callose synthesis, such as stress response and cell-plate formation. In publication IV, we present an in-house developed platform for proteomics with a distributed processing model. This in-house system has been central to many proteomics tasks, including for those presented in publication V, and is being distributed as the Automated Proteomics Pipeline (APP). In publication V, conditions for enrichment of Detergent-Resistant Microdomains (DRM) have been optimized for Populus trichocarpa cell cultures. The proteins enriched in DRM were identified using mass spectrometry based proteomics, and a functional model for DRM was proposed. This model involves proteins specialized in stress response, including callose synthase, and cell signaling. This further strengthens the arguments for DRMs as sites of specific cellular functions and confirms they play a role in glucan synthesis. / <p>QC 20140710</p>