Abstract Continuous software engineering (CSE) has instigated academic debate regarding the rapid, parallel cycles of releasing software and customer experimentation. This approach, originating from Web 2.0 and the software-as-a-service domain, is widely recognised among software-intensive companies today. Earlier studies have indicated some challenges in the use of CSE, especially in the context of business-to-business and product-oriented, embedded systems development. Consequently, research must address more explicit definitions and theoretical models for analysing the prerequisites and organisational capabilities related to the use of CSE. This dissertation investigates various approaches to conducting empirical evaluations related to CSE. The study aims to improve existing models of CSE and to empirically validate them in the context of software companies. The study also aims to accumulate knowledge regarding the use of CSE, as well as its impacts. The case study method is applied for the collection and analysis of empirical data. Twenty-seven interviews are conducted at five companies. In addition, a systematic literature review is used to synthesise the empirical research on agile release engineering practices. Design science research is used to portray the model design and the evaluation process of this dissertation. Three approaches for evaluating CSE are constructed: (1) LESAT for software focuses on enterprise transformation using an organisational self-assessment approach, (2) STH+ extends the “Stairway to Heaven” model and evaluates company practices with respect to evolutionary steps towards continuous experimentation-driven development, and (3) CRUSOE defines 7 key areas and 14 diagnostic questions related to the product-intensive software development ecosystem, strategy, architecture, and organisation, as well as their continuous interdependencies. This dissertation states the relevance of CSE in the context of product-intensive software development. However, more adaptations are anticipated in practices that involve business and product development stakeholders, as well as company external stakeholders. / Tiivistelmä Jatkuva ohjelmistotuotanto on herättänyt keskustelua nopeasta, samanaikaisesta ohjelmistojulkaisemisesta ja asiakaskokeiluista. Toimintatapa on peräisin Web 2.0 ja software-as-a-service yhteydestä, mutta se tunnetaan nykyään yleisesti ohjelmistoja kehittävissä yrityksissä. Aiemmat tutkimukset ovat osoittaneet haasteita jatkuvan ohjelmistotuotannon käytössä. Erityisesti haasteita on havaittu yritykseltä yritykselle liiketoiminnassa ja tuotepainotteisten sulautettujen järjestelmien yhteydessä. Näin ollen on havaittu tarve tutkimuksen avulla kehittää täsmällisempiä määritelmiä ja teoreettisia malleja, joilla voidaan analysoida jatkuvan ohjelmistotuotannon käyttöön liittyviä edellytyksiä ja organisaatioiden kyvykkyyksiä. Tässä väitöskirjassa tutkitaan malleja, joilla voidaan empiirisesti arvioida jatkuvaa ohjelmistotuotantoa. Tutkimuksella pyritään parantamaan nykyisiä malleja ja arvioimaan niiden käyttöä ohjelmistoyrityksissä. Lisäksi tutkimuksella pyritään kasvattamaan tietoa jatkuvasta ohjelmistotuotannosta ja sen vaikutuksista. Tiedon keräämiseen ja analysointiin käytettiin tapaustutkimus menetelmää. Kaksikymmentäseitsemän haastattelua tehtiin viidessä yrityksessä. Lisäksi tehtiin ketterään ohjelmistojulkaisuun keskittyvä systemaattinen kirjallisuuskatsaus. Väitöskirjassa käytetään Design Science Research menetelmää kuvaamaan tutkimuksen eri vaiheita, joissa malleja suunniteltiin ja arvioitiin. Tutkimuksessa rakennettiin kolme tapaa jatkuvan ohjelmistotuotannon arvioimista varten: (1) LESAT for Software keskittyy organisaation muutoskyvykkyyden arviointiin käyttäen itsearviointimenetelmää, (2) STH+, laajentaa ”Stairway to Heaven” mallia ja arvioi yrityksen käytäntöjä eri evoluutioaskelmilla matkalla kohti kokeilupainotteista tuotekehitystä, (3) CRUSOE määrittelee seitsemän pääaluetta ja 14 kysymystä liittyen tuotekehityksen ekosysteemiin, strategiaan, arkkitehtuuriin, organisointiin sekä näiden välisiin jatkuviin riippuvuuksiin. Väitöskirja osoittaa jatkuvan ohjelmistokehityksen olevan merkityksellinen myös tuotepainotteisessa ohjelmistokehityksessä. Nähtävissä kuitenkin on, että useita nykykäytäntöjä on tarvetta muokata. Erityisesti muokkaustarvetta on tuotekehityksen ja liiketoiminnan sidosryhmiin ja yrityksen ulkoisiin sidosryhmiin liittyvissä käytännöissä.

[pt] As tecnologias 3D estão se consolidando em espaços profissionais e, entre suas possibilidades de uso, está seu emprego no contexto educacional. As pesquisas para desenvolvimento de tecnologias partem de um referencial ainda distante da realidade educacional e com predominância de visões advindas do público adulto. Nesse sentido, há espaço para o entendimento de como as crianças experimentam tais tecnologias - impressão 3D (manufatura aditiva), modelagem 3D e escaneamento 3D - no ambiente escolar da Educação Infantil. A presente pesquisa busca investigar qual a contribuição da experimentação das tecnologias 3D para a Educação Infantil, objetivando abrir possibilidades para o entendimento das formas de experimentação pelos alunos. A partir da leitura de documentos governamentais e de teóricos da educação e do desenvolvimento infantil, além do levantamento de outras experiências semelhantes, foi estruturado um experimento composto por três encontros, baseados no método de pesquisa-ação. O primeiro encontro ocorreu no espaço não formal do museu - para apresentação das tecnologias - e os outros dois no ambiente de sala de aula - para a experimentação e reflexão sobre as tecnologias. Para o experimento, foram selecionadas três turmas do último ano da Educação Infantil da escola Curiosa Idade, além do Museu Internacional de Arte Naif. Para a análise dos dados obtidos, foi utilizada a abordagem da Sociolinguística Interacional. Foi constatado que os alunos do último ano da Educação Infantil são capazes de compreender todo o processo, do escaneamento 3D de objetos, passando pela customização via modelagem 3D e chegando ao objeto modificado impresso em 3D. Além disso, verificou-se que a ludicidade e a criatividade são potencializadas pelo uso das tecnologias 3D. / [en] The 3D technologies are ever more present in professional spaces, and among their possibilities is their employment in the educational context. The research for technologies development starts from a referential still far from the educational reality and with visions coming predominatly from the perspective of adults. In this sense, there is room for understanding how children experience such technologies - 3D printing (additive manufacturing), 3D modeling and 3D scanning - in the preschool environment of Educação Infantil (brazilian stage similar to the Early Childhood Education). The present research seeks to investigate the contribution of the 3D technologies experimentation to Educação Infantil, aiming to open possibilities for the understanding of the ways of experimentation by the students. Having reviewed governmental documents and education and child development theorists, besides surveying similar experiences, an experiment was structured consisting of three meetings, based on the action-research method. The first meeting took place in the museum s non-formal space - for the presentation of technologies - and the other two in the classroom environment - for experimentation and reflection on technologies. For the experiment, three groups attending the kindergarten at the Curiosa Idade school, as well as the International Museum of Naif Art, were selected. For the analysis of the obtained data, the approach of Interactional Sociolinguistics was applied. It was found that the students of the kindergarten are able to understand the whole process, from the 3D scanning of objects, to the customization through 3D modeling and to the modified object 3D printed. In addition, it has been found that playfulness and creativity are enhanced by the mediated use of 3D technologies.

Dans une application d’équipement automobile, la conception optimale d’un actionneur nécessite la prise en compte simultané des différents phénomènes physiques ; tant qu’en termes de performances attendues ainsi que les contraintes à respectées. Ces physiques comprennent la performance électromagnétique / électromécanique, comportement thermique et le comportement vibro-acoustique. En prenant en compte le coût et la faisabilité en matières de fabrications, la machine synchro-réluctante (Syncrel) à rotor segmenté a été démontré intéressante pour une application avec des fortes contraintes d’encombrement et thermique. Cette étude a donc pour objective d’évaluer la capacité de la machine Syncrel dans ces différents physiques et démontre les interactions entre eux, qui peuvent affecter les performances de la machine en fonctionnement. Des modèles multi-physiques ont été développés et validés en utilisant une machine prototype conçu précédemment pour un actionneur d’embrayage électrique. En se servant des modèles validés, différents critères de performances des différentes topologies de rotor de la machine Syncrel ont été aussi comparés. A l’issue de l’étude, les modèles électromagnétiques, électromécaniques, thermiques et vibro-acoustiques valides sont à nos dispositions pour être utilisés dans la conception de machine Syncrel en future. La machine Syncrel avec rotor segmenté a été démontrée capable pour être utilisé dans l'application de l'embrayage électrique étudié en particulier. Suite à des évaluations de performance en physique différente, des pistes d'améliorations ont également été proposées. / In an on-board automotive environment, machines optimal design requires simultaneous consideration of numerous physical phenomena; both in terms of expected performance or in terms of constraints to be respected. The physics that can be affected includes the electromagnetic / electromechanical performance, thermal behavior and vibro-acoustic behavior. Among a large choice of machine, with the manufacturer cost and manufacturing concern taken en into account, the synchronous reluctance machine with segmented has been found to be particularly interesting for application with severe ambient temperature and encumbrance limitation. This study has therefore as objectives to evaluate the capacity of the synchronous reluctance machine in ail physics mentioned and eventually shows the interaction between these physics, thus performance alteration of the machine in operated in the automobile equipment environment. Multi-physics model were developed and confronted to experimental validations using a prototype machine that was developed for an electrical clutch. Using the validated model, different performance figures of synchronous reluctance machines with different rotor topologies were compared. Resulting from the study, valid electromagnetic, electromechanical, thermal and vibro-acoustic models are now available to be used as tools in future machine design. The synchronous reluctance with segmented rotor prototype machine has been shown to be capable to be used in the electrical clutch application studied in particular. Following performance evaluations in different physics, suggestions of improvements have also been proposed.

Face un environnement complexe et hyper-compétitif, les firmes sont amenées à reconsidérer leur modèle de création de valeur. Leur réaction s’insère dans le cadre d’une réinvention voire innovation de leur Business Model (BM). Ceci passe indéniablement par une démarche d’expérimentation stratégique. Définie comme un processus par lequel les firmes explorent de nouvelles sources de revenus et testent de nouveaux concepts d’affaires, l’expérimentation stratégique s’associe à un outil de réinvention du BM qui intervient non seulement dans la création de nouveaux BM mais également dans la transformation de BM existants. Nous posons ainsi la question de savoir : Comment concevoir l’expérimentation stratégique des BM des entreprises ? Dans cette perspective, notre recherche vise à dresser un cadre conceptuel et méthodologique de l’expérimentation stratégique. Il s’agit de proposer aux entreprises une aide à la conception d’une méthodologie d’expérimentation de BM. Pour répondre à cette problématique, nous proposons de définir l’expérimentation stratégique comme une théorie combinée du changement en partant du modèle de Van de Ven et Poole (1995) sur les théories de changement et de développement organisationnel. Ceci permet de traduire les processus centraux de l’expérimentation stratégique et d’en saisir les dimensions clés. Dans le cadre d’une approche qualitative avec étude de cas, nous interrogeons trois profils d’acteurs sur leurs registres de conception et de pratique de l’expérimentation. Ensuite, nous élaborons via une analyse inter-profils un modèle générique d’expérimentation stratégique de BM qui s’articule autour de trois temps de l’expérimentation stratégique ; un temps de virtualisation, un temps d’actualisation et un temps d’itérations de processus de rationalisation et d’apprentissage. / In a hypercompetitive environment, firms are obliged to reconsider their revenue formula and to innovate consequently the way they create value and make profit. This lies at the heart of every company’s ability to experiment new Business Models (BM) and becomes a key step in the strategic thinking. Defined as a process by which firms explore new ways of doing business, strategic experimentation takes shape of series of trial and error changes pursued along various dimensions of strategy in an effort to identify and establish a viable basis for competing. Our research examines strategic experimentation as an effective tool for BM reinvention. It answers therefore to the main question of: How to conceive BM experimentation? In this way, we define strategic experimentation as a combined theory of change according to the model developed by Van de Ven and Poole (1995) to explain processes of organizational development and change. We aim at dressing a conceptual and methodological framework for strategic experimentation that would helps managers and academics to conceive and master the process of BM experimentation. Using a qualitative research methodology rooted in a case study approach, we achieved semi-structured interviews with three categories of actors implied in the process of BM experimentation. Our results demonstrate that BM experimentation is organized through four major processes which are exploration, formulation, resources allocation and identification which are articulated by a time of virtualization, a time of actualization, and a time of iterations based on learning and rationalization.

The aim of this dissertation is an analysis of the regulatory framework for the procurement and distribution of stem cells in South Africa. This research includes aspects of the law of obligations, medical law and human rights law as found in the Bill of Rights. More specifically however, this dissertation attempts to bring to attention the shortcomings of chapter 8 of the National Health Act. An examination is undertaken according to the multilayered approach and therefore the proposed regulatory framework is examined within a constitutional framework, an ethical framework, the framework as established by common law, in this case the doctrine of informed consent and lastly within the national legislation framework as found in the National Health Act of 2003 and the regulations made in terms of the Act. This dissertation further entails a brief comparative study of the regulatory mechanisms of the United Kingdom as entrenched in the Human Fertilisation and Embryology Act of 2008 and the Human Tissue Act of 2004 and as practiced by the Human Fertilisation and Embryology Authority and the Human Tissue Authority. The analysis in this dissertation firstly provides an overview of the clinical manifestations and science of stem cell technology. Secondly, the impact of the Constitution of the Republic of South Africa is discussed with particular reference to the Bill of Rights on stem cell research and therapy. The most noteworthy conclusion to be made in this regard is that the embryo is not the bearer of constitutional rights. The ethical guidelines which act as regulatory tools in this field are then discussed with attention to general ethical principles as provided for by the Health Professions Council of South Africa as well as the Medical research Council. The doctrine of informed consent further enjoys attention as it is discussed in context of medical research and key issues are addressed regarding the process of obtaining consent in context of stem cell technologies. Certain recommendations are then made pertaining to the minimum scope required for lawful consent. Lastly a critical analysis is made of chapter 8 of the National Health Act. The findings which are made here lead to further recommendations regarding the regulation of stem cells. / Dissertation (LLM)--University of Pretoria, 2011. / Public Law / unrestricted

In order to ascertain the degree of compatibility in developmental restructuring and behavioral plasticity between two fish species frequently made subject of laboratory research (Metriaclima zebra & Danio rerio), alternative trophic niche exposure experiments utilizing novel three-prong feeding treatments were conducted to obtain morphometric data, which demonstrated both species do bear some degree of plasticity. The results are somewhat complicated by differences in locality of detectable restructuring, which may be due to disparity in the form-function relationship for each species’ lineage. Each is notable in the manner of respective species’ jaw protrusion, as it is driven by anterior kinethmoid rotation in D. rerio. as opposed to force imparted upon the rostral cartilage of the premaxilla’s articular process in M zebra. Each is markedly distinct in the pharyngeal jaw as well, as zebrafish (also toothless at the oral jaw) bear teeth only on the lower set at the posterior of the mouth, while cichlids bear teeth on all jaws and additionally possess a unique, fused lower pharyngeal jaw. However, accounting for this difference in experimental models does allow for direct comparison, both at the morphological/behavioral and potentially the genetic level, though additional research is necessary. The evidence provided here also provides encouragement that more nuanced approaches to laboratory trophic niche exposure experiments could elucidate further evidence on the nature of phenotypic plasticity.

Development of functional neural circuits involves a series of complicated steps, including neurogenesis and neuronal morphogenesis. To understand the molecular mechasnims of neurite complexity, especially neurite branching/arborization, the Drosophila brain, especially MBNs (mushroom body neurons) and PNs (projection neurons) in olfactory circuitry, was used in this dissertation work as the model system to study how two molecules, Dscam and Kr-h1 affect neurite complexity in the Drosophilabrain. For the Drosophila Dscam, through alternative splicing it could encode up to 152,064 distinct immunoglobulin/fibronectin type cell adhesion molecules. Each Dscam isoform is derived from one of the 19,008 ectodomain variants connected with one of the two alternative transmembrane segments and one of the four possible endodomain portions. Recent studies revealed that Dscam was widely required for neurite branching/arborizaiton. However, due to the technical difficulty, the functional roles of Dscam transmembrane variants and ectodomain variants remain unclear. In this thesis work, a microRNA based RNA interference was used to knock down distinct subsets of Dscam isoform. First, loss of Dscam[TM1] versus Dscam[TM2], two distinct Dscam transmembrane variants, disrupted the dendritic versus axonal morphogenesis, respectively. Furthermore, structural analysis suggested that the juxtamembrane portion of transmembrane segment was required for the Dscam protein targeting in dendrites/axons and this differential protein targeting might account for the functional distinction between Dscam[TM1] and Dscam[TM2]. Second, to further address the functional significance of having two Dscam transmembrane variants in axons versus dendrites, the possibility that there might be different usage of Dscam repertoire between axons and dendrites that lead to different levels of morphological complexity between axons and dendrites in the same neuron was examined. To this end, end-in targeting approaches were used to exchange Dscam populations between axons and dendrites. Though the genetic data suggested that Dscam populations were exchanged between axons and dendrites, the phenotypic analysis in various neuronal types revealed that depending on the neuronal types, exchange of Dscam populations between axons and dendrites might primarily affect either axonal or dendritic morphology, suggesting that different usage of Dscam population between axons and dendrites might regulate complex patterns of neurite morphology. Finally, the functions of Dscam exon 4 variants had been addressed in different model neurons in the Drosophilabrain. First, 12 Dscam exon 4 variants were divided into three groups based on their phylogenetic distance. Then, three miRNA constructs were engineered to knock down one group at a time. The genetic data suggested that different Dscam exon 4 variants are differentially required in different neurons to support their proper neuronal morphogenesis. In summary, this part of my thesis work identified and characterized previously unrecognized functions of all these distinct Dscam variants and provided novel insights into how diverse Dscam isoforms regulate the different aspects of neuronal morphogenesis. In the honey bee brain, Kr-h1 is upregulated during the behavioral shift from nursing to foraging when there is increased neurite branching in the brain. To directly examine the hypothesis that altered Kr-h1 expression might regulate morphological complexity of neurites, this research work involved the MARCM (mosaic analysis with a repressible cell marker) and TARGET (temporal and regional gene expression targeting) techniques to analyze the roles of Kr-h1 in Drosophila neuronal morphogenesis. Interestingly, increased expression of Kr-h1 blocked the axon branching and further disrupted the lobe formation in the mushroom body whereas the loss-of-Kr-h1 did not show any apparent neuronal morphogenetic defects. In addition, it was observed that Kr-h1 was expressed when MB (mushroom body) did not undergo active morphogenesis, suggesting its potential anti-morphogenetic activity. Indeed, loss of Kr-h1 (Kruppel homolog 1) enhanced the neuronal morphogenesis that was otherwise delayed due to the defective TGF-beta signaling. Furthermore, Kr-h1 expression was closely linked to ecdysone dependent signaling: Kr-h1 was first regulated by usp (ultraspiracle), which dimerized with various ecdysone receptors and then Kr-h1 expression was essential for proper ecdysone patterning in the larval CNS (central nervous system). Together, though Kr-h1could potentially regulate the neurite complexity, it seems primarily involved in the coordinating ecdysone signaling. In conclusion, the powerful genetic toolkit available in the Drosophila has allowed the investigation in the molecular mechanisms of neuronal morphogenesis and understanding of these mechanisms will enhance our understanding of how the complex nervous system is wired to perform the delicate behaviors.

Amyotrophic lateral sclerosis (ALS) is a terminal neurodegenerative disease that affects motor neurons causing progressive muscle weakness and respiratory failure. In 2011, the presence of a hexanucleotide repeat expansion within chromosome 9 open reading frame 72(C9ORF72) was identified in ALS patient samples, becoming the major known genetic cause for ALS and frontotemporal dementia (FTD). Carriers of this mutation present reduced levels of C9ORF72 mRNA, RNA foci produced by the aggregating expansion and toxic dipeptides generated through repeat-associated non-ATG translation. These findings have led to multiple hypotheses on the pathogenesis of C9ORF72: 1) Haploinsufficiency, 2) RNA gain-of-function, 3) RAN Translation, and 4) Disrupted nucleocytoplasmic trafficking. Due to lack of treatments for this disease, we have pursued an AAV-RNAi dependent gene therapy approach, using an artificial microRNA (amiR) packaged in a recombinant adeno-associated virus (rAAV). After validating our in vitro results, we advanced to in vivo experiments using transgenic mice that recapitulate the major histopathological features seen in human ALS/FTD patients. Adult and neonate mice were injected through clinically relevant routes and our results indicate that AAV9-mediated amiR silencing not only reduced mRNA and protein levels of C9ORF72 but also the expansion derived toxic GP dipeptides. Although our amiR is not targeting the expansion itself but exon 3, we illustrate here that the evident dipeptide decrease is achievable due to the presence of aberrant transcripts in the cytoplasm containing miss-spliced Intron-HRE-C9ORF72 species. These encouraging results have led to the continued testing of this treatment as a therapeutic option for C9ORF72 - ALS patients.

The Tec family tyrosine kinase, Itk, plays an important role in signal transduction following T cell receptor engagement. Several prior studies have established the importance of Itk in immune system processes, such as T cell development and T cell activation. Additional biochemical studies have found that Itk specifically functions within a multi-molecular signalosome complex, which ultimately functions to provide a platform by which Itk can phosphorylate and activate PLC-γ1, a crucial step in T cell activation. To further study how Itk regulates distinct immune outcomes via T cell effector processes within the peripheral immune system, and to further understand how Itk functions in T cells in response to a physiological ligand-receptor interaction, I crossed Itk-deficient mice to mice transgenic for a TCR specific for a moth cytochrome C peptide. My studies have established a unique role for Itk in several important aspects of T cell function. Following T cell activation, I identified an imperative role for Itk in activation-induced cell death via FasL, a mechanism of immune homeostasis. Furthermore, I found Itk plays a unique role in the process of T cell differentiation, where Itk positively regulates the induction of cytokine genes, such as IL-4, while negatively regulating the induction of T-bet, a transcription factor important for Th1 differentiation. Lastly, following T cell differentiation, I found that Itk mRNA and protein are up-regulated during Th2 differentiation, while Rlk, a related Tec kinase, disappears rapidly from Th2 cells, indicating a critical role for Itk in Th2 cell function. Collectively, my thesis work has more clearly defined an important function for Itk not only in TCR signaling, but also in immune processes such as T cell differentiation and activation-induced cell death that are required for proper immune function.

In mammals, newly synthesized proteins destined for secretion are translocated cotranslationally into the lumen of the Endoplasmic Reticulum (ER). Once inside, these nascent polypeptide chains are bound by a lumenal ER protein called BiP (Immunoglobulin Binding Protein) or Grp 78 (Glucose Regulated Protein 78). It is hypothesized that this binding is necessary to protect the nascent chains until they are properly folded or assembled with other subunits. When the proteins are folded and assembled, they are released from BiP by a process that is dependent on ATP hydrolysis. Since ATP is synthesized mainly in the mitochondria, we hypothesized that there must be an ATP transporter in the ER which would allow the protein mediated transport of ATP from the cytosol into the ER lumen. We studied the transport of ATP in vitro and found that ATP enters the lumen of the ER in a saturable manner with a Kmapp~3μM. ATP transport is dependent on time, protein, and vesicle integrity, it is also inhibited by the general anion transport inhibitor, 4,4' diisothiocyano-2,2'-disulfonic acid stilbene (DIDS). We also found that the transport was inhibited by membrane impermeable protein modifying agents such as N-ethlymaleamide (NEM) and Pronase when added to intact ER vesicles. These results suggest that the transport is mediated by a protein with an active cytoplasmic face. Using monoclonal and polyclonal antibodies to BiP and Grp94 (another resident ER protein) and U.V. crosslinking, we demonstrated that after transport of ATPα32P into intact vesicles, radiolabeled BiP and Grp94 could be immunoprecipitated. We also found that labeling of lumenal proteins with ATP is dependent on the transport of ATP. Finally using ATP labeled with 35S, we concluded that BiP was able to bind intact ATP and we confirmed earlier work that BiP was thiophosphorylated while Grp94 is not. The second area of study involves processes that occur further along the secretory pathway in the Golgi apparatus. It was known from previous work that the nucleotide sugar substrates necessary for the synthesis of the linkage region, UDP-xylose (UDP-Xyl), UDP-galactose (UDP-Gal) and UDP-glucuronic acid (UDP-GlcA) were transported into the Golgi apparatus from the cytosol via protein mediated transporters. In order to eventually purify one of these transporter proteins, we wanted to reconstitute their activities. We were able to reconstitute the activities that exhibited kinetic parameters and inhibitor sensitivities very similar to those seen in intact Golgi vesicles. In the case of UDP-xylose it was necessary to prepare the liposomes using endogenous Golgi lipids in order to get transport activity similar to that seen in the intact Golgi vesicles. This suggested a specific lipid requirement for the UDP-xylose transporter. These transporters seem to be antiporters, whereby the nucleotide sugar enters the lumen of the Golgi coupled to the equimolar exit of the corresponding nucleoside monophosphate (Hirschberg, C.B. and Snider, M.D. 1987). We also showed that we could reproduce the hypothesized antiporter system in the reconstituted proteoliposomes by preloading the proteoliposomes with the putative antiporter molecule UMP. The rationale for developing the reconstituted system is eventually to use this system to purify one of these nucleotide sugar translocators. In the last set of studies, I have shown that this reconstituted system can be used to monitor the purification of the UDP-galactose translocator. Using column chromatography we were able to purify this membrane translocator protein 45,000 fold from a rat liver homogenate.