Financieel duurzaam leiderschap:financials en MVO

De doelstelling van dit onderzoek is duidelijkheid krijgen over hoe een duurzame financial denkt en handelt. De centrale vraag die wij hierbij stellen is: “Hoe denkt en handelt een duurzame financial?”. Op basis van deze hoofdvraag zijn wij gekomen tot drie deelvragen. De eerste deelvraag luidt: “Wat is MVO?” Deze vraag stellen wij om het theoretische kader van het onderzoek te definiëren. In de ISO 26000 zijn de richtlijnen voor MVO vastgelegd. De definitie van de ISO 26000 van MVO is: “maximaliseer je bijdrage aan natuur en milieu, mens en economie.” “Je houdt rekening met de behoeften van nu en van toekomstige generaties.” De ISO 26000 kent zeven kernthema’s die van belang zijn voor elke type organisatie. Deze kernthema’s zijn: behoorlijk bestuur, mensenrechten, arbeidsomstandigheden, milieu, eerlijk zaken doen, klant/consument-aangelegenheden en maatschappelijke betrokkenheid

Perception and action of nod factors in Rhizobium-legume symbiosis

Rhizobium bacteria are able to invade the roots of their leguminous hosts and trigger the formation of a new organ, the root nodule. In these nodules the bacteria are hosted in the proper environment for fixing atmospheric nitrogen into ammonia, making plant growth independent of nitrogen compounds from the soil. The interaction between the bacterium and the host plant starts with a signal exchange, when flavonoids excreted by the plant induce the transcription of bacterial nodulation (nod) genes. Induction of these nod genes leads to the synthesis of specific lipo-oligosaccharides (Nod factors) required for inducing various root responses like root hair deformation, infection thread and nodule primordia formation. The aim of the research described in this thesis is to contribute to the insight in the mechanism by which Nod factors initiate root nodule formation. To address this issue it is essential to have a plant system in which both the morphological and molecular changes induced by Nod factors can be studied. We adapted a root hair deformation assay for Vicia sativa (vetch), growing the seedlings in Fahraeus slides, to study the activity and fate of the various Nod factors secreted by Rhizobium leguminosarum by viciae in a fast, simple and semiquantitative way (Chapter 2). Root hair deformation in this assay is limited to root hairs in a specific developmental stage and involves a reinitiation of tip growth which is visible within 3 hours after Nod factor application. In an attempt to identify genes the expression of which is induced in an immediate respons to Nod factors we used the differential RNA display method to compare the pattern of cDNAs expressed in the zone of the vetch root where root hair deformation occurs at 0, 1 and 3 hours after Nod factor addition. Surprisingly, the sequence of one of the isolated clones already expressed I hour after Nod factor application coded for leghemoglobin. This gene was used to show that gene expression and root hair deformation are not coupled and to investigate how NH4NO3* might block root hair deformation (Chapter 3). Root hair deformation induced by Nod factors involves a reinitiation of growth in the existing root hair tip, a mechanism reminiscent of ethylene induced tip growth leading to the formation of root hairs in the epidermis. Since ethylene is a potent inhibitor of cortical cell division there seems to be a paradox in its action during the initial interaction between rhizobia and its host. We showed that ethylene is not invoved in the root hair deformation process, but it is one of the factors involved in giving positional information determining where nodule primordia can be induced (Chapter 4). How Nod factors are perceived and induce the various responses in the root is poorly understood. Considering that Nod factors are active at very low concentrations it is likely that they are recognized by receptors. Besides a biochemical approach to search for such receptors it win be very important to isolate and analyse host mutants disturbed in the early staves of the interaction with Rhizobium. We chow to focus on the sym2 A gene originating from Afghanistan pea since the presence of this gene puts more stringent structural demands on the Nod facotrs secreted by Rhizobium leguminosarum by viciae. After detailed analysis of the phenotype conferred by sym2 A we propose that Sym2 controls the infection process in the epidermis, possibly representing a Nod factor receptor (Chapter 5).</p

Between Art and Commerce

Contact puppetry is a western interpretation of the ancient Japanese bunraku puppetry. In the last decade or so, the popularity seems to have grown exponentially. As part of the performing arts, contact puppetry is a creative industry. These industries are characterized by seven properties, according to Richard Caves in his book Creative Industries; Contracts Between Art and Commerce (2000). By means of three modern-day contact puppetry productions (War Horse, Disney’s The Little Mermaid, and A Dog’s Heart), the aim of this thesis is to identify if everyday practice in contact puppetry follows the creative industry ‘rules’ as portrayed by Caves’ properties. And if so, what can be (preliminary) said from a cultural economic point of view about the economic and artistic reasons to use contact puppetry

A Model for the Development of the Rhizobial and Arbuscular Mycorrhizal Symbioses in Legumes and Its Use to Understand the Roles of Ethylene in the Establishment of these two Symbioses

We propose a model depicting the development of nodulation and arbuscular mycorrhizae. Both processes are dissected into many steps, using Pisum sativum L. nodulation mutants as a guideline. For nodulation, we distinguish two main developmental programs, one epidermal and one cortical. Whereas Nod factors alone affect the cortical program, bacteria are required to trigger the epidermal events. We propose that the two programs of the rhizobial symbiosis evolved separately and that, over time, they came to function together. The distinction between these two programs does not exist for arbuscular mycorrhizae development despite events occurring in both root tissues. Mutations that affect both symbioses are restricted to the epidermal program. We propose here sites of action and potential roles for ethylene during the formation of the two symbioses with a specific hypothesis for nodule organogenesis. Assuming the epidermis does not make ethylene, the microsymbionts probably first encounter a regulatory level of ethylene at the epidermis–outermost cortical cell layer interface. Depending on the hormone concentrations there, infection will either progress or be blocked. In the former case, ethylene affects the cortex cytoskeleton, allowing reorganization that facilitates infection; in the latter case, ethylene acts on several enzymes that interfere with infection thread growth, causing it to abort. Throughout this review, the difficulty of generalizing the roles of ethylene is emphasized and numerous examples are given to demonstrate the diversity that exists in plants

Root genomics: towards digital in situ hybridization

Separation of cell types and developmental stages in the Arabidopsis root and subsequent expression profiling have yielded a valuable dataset that can be used to select candidate genes for detailed study and to start probing the complexities of gene regulation in plant development

The Arabidopsis JAGGED LATERAL ORGANS (JLO) gene sensitizes plants to auxin

Plant growth and development of new organs depend on the continuous activity of the meristems. In the shoot, patterns of organ initiation are determined by PINFORMED (PIN)-dependent auxin distribution, while the undifferentiated state of meristem cells requires activity of KNOTTED LIKE HOMEOBOX (KNOX) transcription factors. Cell proliferation and differentiation of the root meristem are regulated by the largely antagonistic functions of auxin and cytokinins. It has previously been shown that the transcription factor JAGGED LATERAL ORGANS (JLO), a member of the LATERAL ORGAN BOUNDARY DOMAIN (LBD) family, coordinates KNOX and PIN expression in the shoot and promotes root meristem growth. Here we show that JLO is required for the establishment of the root stem cell niche, where it interacts with the auxin/PLETHORA pathway. Auxin signaling involves the AUX/IAA co-repressor proteins, ARF transcription factors and F-box receptors of the TIR1/AFB1–5 family. Because jlo mutants fail to degrade the AUX/IAA protein BODENLOS, root meristem development is inhibited. We also demonstrate that the expression levels of two auxin receptors, TIR1 and AFB1, are controlled by JLO dosage, and that the shoot and root defects of jlo mutants are alleviated in jlo plants expressing TIR1 and AFB1 from a transgene. The finding that the auxin sensitivity of a plant can be differentially regulated through control of auxin receptor expression can explain how different developmental processes can be integrated by the activity of a key transcription factor