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Bacterial secretion systems have been playing essential roles in modulating the microbiota of most ecological niches. Among a variety of secretion systems, the Type VI Secretion System (T6SS), a nanomachine widely distributed in Gram-negative bacteria, is gaining increasing attention due to its involvement in microbe-microbe and microbe-host interactions through secreting toxins into host cells, microbial competitors, and the extracellular milieu. Most secreted toxins, also known as T6SS effectors, have bacteriostatic effects upon delivery into competing bacteria, and therefore bacteria with potent T6SS may acquire competition advantage and represent promising biological control agents (BCAs). The main body of this dissertation will focus on the characterization of the T6SS of a phytopathogen, Acidovorax citrulli (strain AAC00-1), and the secreted T6 effectors, and will also discuss the possible application of AAC00-1 as a BCA. The seed-borne, gram-negative A. citrulli is able to cause bacterial fruit blotch (BFB) disease and then result in devastating decrease in yields of important cucurbits including watermelon, melon, squash and cucumber. Our inter-microbial competition assays demonstrate that AAC00-1 contains an active T6SS and presents a dramatic antimicrobial activity against a variety of microbes, including Gram-negative bacteria, Gram-positive bacteria, and yeast, dependent upon its T6SS. A group of novel non-enzymatic effectors, Hyde1 proteins, delivered into prey cells through the T6SS, are responsible for this broad-spectrum antimicrobial activity. Expressing Hyde1 or its N-terminal transmembrane domain shows significant toxicity in both E. coli and AAC00-1, and the toxicity of Hyde1 can be counteracted by its immunity protein, Hyde2. A non-pathogenic AAC00-1 strain suppresses the growth of multiple deleterious phytopathogens in planta and protects plant host. Transgenic plants expressing either full-length Hyde1 or its transmembrane domain demonstrate improved resistance against both bacterial and oomycete pathogens. Altogether, we characterize the T6SS killing of AAC00-1, identify the determinant effectors and discuss the application of both AAC00-1 and its T6SS effector in plant disease management. Additionally, in order to develop molecular tools better serving our T6SS-related studies, we successfully generate a series of salicylic acid (SA)-inducible vectors, functioning in A. citrulli, that can be used for inducible gene expression, protein purification and other applications. The core regulatory component that we employ, is a transcriptional regulator, Sal7AR-V295F, due to its responsiveness to salicylate. By cloning this fragment to a broad-host-range plasmid, in this study, we establish multiple SA-inducible vectors that may be used in most Gram-negative bacteria. When using the E. coli strain C41(DE3) as the expression host, protein purification can be conducted routinely, upon the addition of affinity tags to our vectors, such as the maltose-binding protein (MBP) tag. Combining the modified vectors with the robust NanoLuc binary Technology (NanoBiT), we are able to devise a novel bacteria two-hybrid system as an effective method to detect protein-protein interaction. Two complementary fragments of the NanoLuc protein, LgBiT and SmBiT, with extremely low affinity, are fused to potential interactors, and they will be brought into proximity and reconstitute NanoLuc bioluminescence upon the occurrence of interaction. This system is used in our T6SS study to validate the interaction between Hyde1 toxin and its cognate immunity protein. Another fragment, HiBiT, which automatically interacts with LgBiT and reconstitutes NanoLuc, is cloned to the SA-inducible vector as well, enabling us to generate a split-NanoLuc-based method, for the purpose of detecting secretion of tagged T6 toxins into the prey bacterial cells expressing LgBiT. Overall, our SA-inducible vectors and their further modifications enrich the molecular tool repertoire for T6SS-related studies. / Doctor of Philosophy / Effective crop disease management is critical for agricultural production. Chemical spray has been practiced as one major approach to control plant diseases for more than a decade. However, increase of pesticide application could threaten public health and the environment. Biological control has been considered as one of the effective and environmental-friendly alternative approaches for disease control. In this dissertation, we identify that, Acidovorax citrulli (strain AAC00-1), a Gram-negative pathogen causing bacterial fruit blotch (BFB) disease in Cucurbitaceae, could be a potential biological control agent (BCA), because it carries an active Type VI Secretion System (T6SS), and the T6SS has been shown to contribute to the protective effects of many plant-associated BCAs. T6S is believed to mediate inter-bacterial competition through secreting toxins into microbial competitors. Most secreted toxins, also known as T6SS effectors, have bacteriostatic effects upon delivery into competing bacteria, and therefore bacteria with potent T6SS may acquire competition advantage and represent promising BCAs. We demonstrate that AAC00-1 suppresses the growth of multiple phytopathogens, depending upon its T6SS. Expressing ten out of eleven microbial toxins, encoded by Hyde1 genes, in E. coli shows significant toxicity. The wild type AAC00-1 strain inhibits the growth of multiple Arabidopsis leaf bacterial isolates, while an AAC00-1 Hyde1 mutant loses this capacity. The antimicrobial activity of AAC00-1 is proven to be broad-spectrum since this strain also shows inhibitory effect on the growth of Gram-positive bacteria and yeast. In planta disease assay suggests that a non-pathogenic AAC00-1 mutant defective in Type III secretion system (T3SS) maintains its capacity to suppress disease symptoms and pathogen growth on plants infected with different phytopathogens. Our study demonstrates the viability of the employment of non-pathogenic A. citrulli as an effective BCA in plant disease management.

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Vi lever i en värld av klimatförändringar där det ständigt söks efter lösningar för att minska utsläppen av växthusgaser. IMO har infört SEEMP:en med målet att reducera utsläppen från världshandelsflottan och därmed öka dess energieffektivitet. Med denna bakgrund har syftet varit att undersöka hur svenska tankrederier implementerat och tillämpat SEEMP:en samt kartlägga åsikter kring den. En kvalitativ metod har använts för att på djupet undersöka rederiernas tillvägagångssätt. Undersökningen omfattar fyra semistrukturerade intervjuer med totalt sex personer ifrån två rederier där både ombord- och landanställda finns representerade. Resultatet visade att rederierna implementerat SEEMP:en efter IMO:s riktlinjer, i samråd med sitt klassningssällskap, där rederierna också har försökt ta tillvara möjligheten att energieffektivisera sin organisation. Båda rederierna såg positivt på införandet av SEEMP:en och menade att den borde införts tidigare. Det framkommer dock faktorer som anses motverka SEEMP:ens fulla potential, bland annat att strukturen i branschen måste ändras för att kunna applicera SEEMP:en fullt ut. / We live in a world of climate change where finding a solution to reducing the emission of GHG is a continuous pursuit. To reduce the emission from global shipping IMO has adopted the SEEMP consequently making the shipping industry more energy efficient. With this in mind the purpose of this study has been to review the implementation and usage of the SEEMP among Swedish shipping companies trading oil. Furthermore, the views of the involved parties with regard to the SEEMP were also investigated. In order to deeply analyze the companies´ approach to the SEEMP a qualitative research method has been used. The study consists of four semi-structured interviews with sex persons from two shipping companies including both onshore and ship-based personnel. The result shows that the implementation has been carried out in consultation with their own classification societies and with the IMO guidelines in mind. They have also tried to take the opportunity to make their organization more energy efficient. Both companies welcomed the adoption of the SEEMP and were of the opinion that it shouldhave been introduced at an earlier stage. However, some barriers to the SEEMP have been found, for example the operational structure of the shipping industry.

ABSTRACT Vi-Agroforestry communication has been studied to see how they use communication as a tool to attract donors. The aim is to be able to contribute to shed some light on the importance of image and text as a unified communication. Its about acknowledge what the sender (aid organization) sends out to tell potential donors. It examines how the organization communicates the problems they want to solve, which method they want to solve it with and why their organization should be the preferred option before the interest is gone by the recipient. By examine the reliability (ethos), the emotional connection (pathos) and the factual conviction (logos) of the Vi Agroforestry communication it helps to understand the organizations way of communicate with their listeners. The study examined Vi-Agroforestry communication through image and text. The author hopes to contribute to explore what an aid organization, like Vi-Agroforestry, choose to focus on regarding when they get to talk about their organization and their work. The organization has been analyzed based on the rhetorical basics to go on to see which framework they create their communications. / SAMMANFATTNING Vi-skogens kommunikation har studerats för att kunna se på hur de använder sig av kommunikation som verktyg för att locka givare. Förhoppningen är att kunna bidra med att öppna upp betydelsen av bild och text i sitt sammanhang vid kommunikation. Det handlar om vad avsändaren (biståndsorganisationen) skickar ut för att nå ut till potentiella givare. Det undersöks hur organisationen kommunicerar ut de problem som de vill lösa, vilken metod de vill lösa den med och varför just deras organisation ska vara det självklara alternativet innan intresset är borta hos mottagaren. Detta studeras med hjälp av att undersöka den tillförlitlighet (ethos), den känslomässig koppling (pathos) och den saklig övertygelse (logos) i Vi-skogens kommunikation. Studien studerat Vi-skogens kommunikation genom bild och text. Författaren hoppas bidra med att undersöka vad en biståndsorganisation, som Vi-skogen, väljer att belysa och fokusera på när de själva får berätta om sin organisation och sitt arbete. Organisationen har analyserats utifrån de retoriska grunderna för att gå vidare för att se vilket ramverk de skapar sin kommunikation.

We report the possibility to control the tilting of nanoneedles and nanowires by using structured sapphire substrates. The advantage of the reported strategy is to obtain well oriented growth along a single direction tilted with respect to the surface normal, whereas the growth in other directions is suppressed. In our particular case, the nanostructures are tilted with respect to the surface normal by an angle of 58°. Moreover, we demonstrate that variation of the nanostructures shape from nanoneedles to cylindrical nanowires by using SiO2 layer is observed.

Die Verfügbarkeit von Metallen in der Geo- und Biosphäre wird durch deren chemische Form, die Speziation, bestimmt. Zur Analyse der Speziation gibt es eine Vielzahl von Techniken. Für spektroskopische Methoden sind untersuchbare Konzentrationsbereiche unter anderem durch entsprechende Detektionsgrenzen eingeschränkt. Vor allem für niedrige Konzentrationen (< 10 µM), wie sie für viele natürliche Systeme von Bedeutung sind, ist die Lumineszenzspektroskopie ein geeignetes Werkzeug. Die Zerlegung spektroskopischer Daten von komplexen Systemen stellt eine zusätzliche Herausforderung dar. Zur Extraktion spektraler Informationen individueller chemischer Spezies werden moderne mathematische Verfahren verwendet. Die so erhaltene spektroskopische Charakterisierung kann zur strukturellen und thermodynamischen Interpretation genutzt werden. In dieser Arbeit wurde die parallele Faktoranalyse (PARAFAC) zur Auswertung spektroskopischer Datensätze genutzt. Diese Technik wurde hier erstmals auf Uranyl(VI)-Systeme angewendet, wodurch eine umfassende lumineszenzspektroskopische Charakterisierung der Uranyl(VI)-Hydrolyse generiert wurde. Zusätzlich wurde der bestehende PARAFAC-Algorithmus (N-way Toolbox) erweitert. Damit wird die Zerlegung auf chemisch interpretierbare Ergebnisse beschränkt und eine direkte Extraktion thermodynamischer Daten ermöglicht. Für die mononuklearen Hydrolysespezies konnten korrigierte Komplexstabilitätskonstanten vorgeschlagen werden, wodurch entsprechende Speziationsrechnungen belastbarer werden. Die extrahierten spektralen Eigenschaften einzelner Spezies wurden anschließend sorgfältig analysiert. Dazu wurden quantenmechanische sowie semiempirische Ansätze genutzt. Neben einerValidierung der angenommenen Speziesbezeichnung wurde dadurch erstmals eine fundierte lumineszenzspektroskopische Signal-Struktur-Beziehung für die Uranyl(VI)-Hydrolyse generiert. Die entwickelten Algorithmen wurden im Rahmen der Arbeit auf komplexere Systeme des Uranyl(VI) und Europium(III) übertragen und deren Gültigkeit nachgewiesen. So konnten neue Erkenntnisse zur Lumineszenzlöschung des Uranyl(VI)-Ions und der Europium(III)-Hydrolyse gewonnen werden. Zudem wurde eine Strategie zur einfachen und akkuraten Bestimmung der Anzahl von Bindungsstellen am Beispiel des Proteins Calmodulin vorgestellt. Der aufgezeigte breite Anwendungsbereich wird zusätzlich durch die erfolgreiche Übertragung der SpecConst-Erweiterung auf andere spektroskopische Techniken (am Beispiel der UV-vis Spektroskopie) erweitert. Die vorgestellten Werkzeuge verbessern die Auswertung spektroskopischer Daten und erweitern das damit verbundene Verständnis komplexer umweltrelevanter Systeme.