Phloem loading is the process by which sugars are loaded into the phloem of source leaves and then subsequently transported to sink organs via bulk flow driven by hydrostatic pressure. Three loading mechanisms are described: passive, polymer trap, and apoplastic loading. In passive loading, sucrose diffuses from mesophyll through plasmodesmata into the phloem. The two energized loading mechanisms are the polymer trap and apoplastic loading. In the polymer trap, sucrose moves into intermediary cells and is synthesized into oligosaccharides that become "trapped." In apoplastic loading, sucrose is transported into the apoplast by SWEETs, and subsequently taken up by SUTs in a proton-sucrose symport mechanism, concentrating sucrose in companion cells. Herbaceous species tend to use active loading, while woody species tend to use passive loading. Confirming either passive or energized loading is not without ambiguity. Cotton was investigated as a model because its phloem loading mechanism is ambiguous. Cotton was

Background: Alterations of hypothalamic–pituitary–adrenal (HPA) axis activity and serotonergic signaling are implicated in the pathogenesis of human obesity and may contribute to its metabolic and mental complications. The association of these systems has not been investigated in human obesity. Objective: To investigate the relation of HPA responsiveness and serotonin transporter (5-HTT) availability in otherwise healthy individuals with obesity class II or III (OB) compared to non-obesity controls (NO). Study participants: Twenty-eight OB (21 females; age 36.6 10.6 years; body mass index (BMI) 41.2 5.1 kg/m2) were compared to 12 healthy NO (8 females; age 35.8 7.4 years; BMI 22.4 2.3 kg/m2), matched for age and sex. Methods: HPA axis responsiveness was investigated using the combined dexamethasone/corticotropin-releasing hormone (dex/CRH) test, and curve indicators were derived for cortisol and adrenocorticotropic hormone (ACTH). The 5-HTT selective tracer [11C]DASB was applied, and parametric images of the binding potentials (BPND) were calculated using the multilinear reference tissue model and evaluated by atlas-based volume of interest (VOI) analysis. The self-questionnaires of behavioral inhibition system/behavioral activation system (BIS/BAS) with subscales drive, fun-seeking and reward were assessed. Results: OB showed significant positive correlations of ACTH curve parameters with overall 5-HTT BPND (ACTHAUC: r = 0.39, p = 0.04) and 5-HTT BPND of the caudate nucleus (ACTHAUC: r = 0.54, p = 0.003). In NO, cortisol indicators correlated significantly with BPND in the hippocampus (cortisolAUC: r = 0.59, p = 0.04). In OB, BAS reward was inversely associated with the ACTHAUC (r = 0.49, p = 0.009). Conclusion: The present study supports a serotonergic-neuroendocrine association, which regionally differs between OB and NO. In OB, areas processing emotion and reward seem to be in-volved. The finding of a serotonergic HPA correlation may have implications for other diseases with dysregulated stress axis responsiveness, and for potential pharmacologic interven-tions.

No / The L-glutamate transporter GLT-1 is an abundant central nervous system (CNS) membrane protein of the excitatory amino acid transporter (EAAT) family that controls extracellular L-glutamate levels and is important in limiting excitotoxic neuronal death. Using reverse transcription-polymerase chain reaction, we have determined that four mRNAs encoding GLT-1 exist in mouse brain, with the potential to encode four GLT-1 isoforms that differ in their N and C termini. We expressed all four isoforms (termed MAST-KREK, MPK-KREK, MAST-DIETCI, and MPK-DIETCI according to amino acid sequence) in a range of cell lines and primary astrocytes and show that each isoform can reach the cell surface. In transfected human embryonic kidney (HEK) 293 or COS-7 cells, all four isoforms support high-affinity sodium-dependent L-glutamate uptake with identical pharmacological and kinetic properties. Inserting a viral epitope (tagged with V5, hemagglutinin, or FLAG) into the second extracellular domain of each isoform allowed coimmunoprecipitation and time-resolved Forster resonance energy transfer (tr-FRET) studies using transfected HEK-293 cells. Here we show for the first time that each of the four isoforms is able to combine to form homomeric and heteromeric assemblies, each of which is expressed at the cell surface of primary astrocytes. After activation of protein kinase C by phorbol ester, V5-tagged GLT-1 is rapidly removed from the cell surface of HEK-293 cells and degraded. This study provides direct biochemical evidence for oligomeric assembly of GLT-1 and reports the development of novel tools to provide insight into the trafficking of GLT-1.

Med fokus på att öka lönsamheten för sina medlemmar strävar Norra Skog ständigt efter att förbättra och effektivisera sin logistik för att hantera det ständigt föränderliga flödet av massaved från skogsavlägg till industri. För att uppnå detta har företaget implementerat Woodflow, en avancerad programvara för logistikoptimering. I linje med det ökande intresset för att minska transportkostnader och främja hållbarhet inom transportnätverket, har det också börjat väcka intresse för att undersöka möjligheterna till att utöka användningen av tågtransporter för massaved. Detta examensarbete syftar till att analysera och optimera Norra Skogs transportflöde av massaved med målet att minimera transportkostnader och undersöka möjligheterna till att minska koldioxidutsläpp inom transportflödet. Arbetet inleddes med en grundlig litteraturstudie för att skapa en förståelse för leveranskedjan för massaved inom skogsindustrin samt ge en bakgrund till den optimeringsteori som ligger till grund för programvaran Woodflow.  Genom användning av Woodflow utfördes olika scenarioanalyser för att utvärdera olika strategier och metoder för att optimera transportflödet. Relevanta data för projektet samlades in och bearbetades för att förbereda indata till programvaran och möjliggöra analys av informationen om transportflöden för massaved. De undersökta scenarierna inkluderade ett scenario som speglade det faktiska transportflödet år 2023 och ett scenario med optimerade lastbilstransporter som användes som referenspunkt. Vidare genomfördes ett scenario med fria tåg- och lastbilstransporter med syftet att undersöka det optimala transportflödet som minimerar transportkostnader. Införande av nya terminaler och uteslutande av en befintlig terminal undersöktes i ett scenario och dessutom utfördes en analys av minimering av koldioxidutsläpp och transportkostnader genom att tillämpa en premiekostnad som representerade lastbilstransporternas högre koldioxidutsläpp. Till sist genomfördes ett framtidsscenario som syftar till att undersöka hur Norra Skog bör planera för sina transporter i framtiden utifrån prognoser av ökade tillgångsvolymer. Genom att noggrant utvärdera dessa olika scenarier söker arbetet efter de mest effektiva och hållbara lösningarna för Norra Skogs transportflöde för massaved. Resultatet visar på att det finns potential till stora kostnadsbesparingar och betydande minskningar av koldioxidutsläpp genom att optimera lastbilstransporterna från det faktiska utfallet 2023. Därefter finns ytterligare kostnadsbesparingar att hämta genom att optimera tågflödet och transportera mer volym via detta mer hållbara transportslag. Samtliga optimeringar av tågflödet, förutom framtidsscenariot med ökad tillgång, bidrar till ytterligare minskningar av koldioxidutsläpp och det anses därav vara av intresse för Norra Skog att fortsatt undersöka och utvärdera möjligheten att utöka tågtransporterna. Det är främst terminalen Storuman som visar på stor potential för fler antal tågavgångar, medan Hissmofors och Bastuträsk överlag visar minst potential för utökning av tågtransporter. Vidare visar terminalen Östavall ytterligare potential för ökad transport av massaved via tåg genom att helt ersätta terminalen Ånge. / Focusing on increasing profitability for its members, Norra Skog continuously strives to improve and streamline its logistics to manage the ever-changing flow of pulpwood from forest sites to industry. To achieve this, the company has implemented Woodflow, an advanced logistics optimization software. In line with the growing interest in reducing transportation costs and promoting sustainability within the transport network, there has also been increasing interest in exploring the possibilities of expanding the use of rail transport for pulpwood. This thesis aims to analyze and optimize Norra Skog's transport flow of pulpwood with the goal of minimizing transportation costs and exploring possibilities to reduce carbon dioxide emissions within the transport flow. The work began with a thorough literature review to create an understanding of the supply chain for pulpwood in the forestry industry and then provide a background to the optimization theory underlying the Woodflow software. Using Woodflow, various scenario analyses were conducted to evaluate different strategies and methods for optimizing the transport flow. Relevant data for the project was collected and processed to prepare input for the software and enable the analysis of information on pulpwood transport flows. The scenarios examined included one that reflected the actual transport flow in 2023 and one with optimized truck transports used as a reference point. Furthermore, a scenario with free rail and truck transports was conducted to investigate the optimal transport flow that minimizes transportation costs. The introduction of new terminals and the exclusion of an existing terminal were examined in one scenario, and an analysis of minimizing carbon dioxide emissions and transportation costs was also performed by applying a premium cost representing the higher carbon dioxide emissions of truck transports. Finally, a future scenario was conducted to examine how Norra Skog should plan its transports in the future based on forecasts of increased supply volumes. By carefully evaluating these different scenarios, the work seeks the most efficient and sustainable solutions for Norra Skog's pulpwood transport flow. The results show that there is potential for significant cost savings and substantial reductions in carbon dioxide emissions by optimizing truck transports from the actual outcome in 2023. Further cost savings can be achieved by optimizing the rail flow and transporting more volume with this more sustainable mode of transport. All optimizations of the rail flow, except for the future scenario with increased supply, contribute to further reductions in carbon dioxide emissions and are therefore considered of interest for Norra Skog to continue evaluating the possibility of expanding rail transports. It is mainly the terminal Storuman that shows great potential for an increased number of rail departures, while Hissmofors and Bastuträsk generally show the least potential for the expansion of rail transports. Furthermore, the Östavall terminal shows additional potential for increased transport of pulpwood by rail by completely replacing the Ånge terminal.

Glutamat ist der wichtigste exzitatorische Neurotransmitter im Zentralnervensystem der Säugetiere. Die präzise Kontrolle des extrazellulären Glutamatspiegels ist für eine normale synaptische Transmission wichtig und erforderlich, um die Neurone vor Exzitotoxizität zu schützen. Im Gehirn sorgen vor allem verschiedene hochaffine Na+-abhängige Glutamattransporter für diese Kontrolle. In der vorliegenden Arbeit wurde deshalb untersucht, welchen Einfluß die Inhibition der Glutamattransporter auf die exzitatorische synaptische Transmission in Schicht III, einer Region in der bei Alzheimer-Demenz, Schizophrenie und Epilepsie häufig Zellschädigungen und Zellverluste beobachtet werden, und Schicht V des medialen entorhinalen Kortex (mEC) hat. Extrazelluläre Messungen in den Schichten III und V der Ratte zeigten, daß die verwendeten Transport-Inhibitoren signifikant die negativen Feldpotentialkomponenten beider Schichten reduzierten. Schichtspezifische Unterschiede konnten dabei nicht festgestellt werden, was auf eine ähnliche Glutamatregulation in beiden Schichten schließen läßt. Für die anschließenden intrazellulären und patch-clamp Messungen wurden aus diesem Grund nur noch Neurone der Schicht III untersucht. Beide Transport-Inhibitoren (L-trans-2,4-PDC und DL-TBOA) reduzierten die Amplituden der pharmakologisch isolierbaren EPSPs/EPSCs ohne die Kinetik zu beeinflussen. Diese reduzierende Wirkung konnte durch trans-(±)-ACPD, einen Agonisten der Gruppe I und II metabotropen Glutamatrezeptoren (mGluRs), nachgeahmt werden. Die Vorinkubation der Hirnschnitte mit dem unspezifischen Gruppe I und II mGluR-Antagonisten MCPG verhinderte die durch trans-(±)-ACPD hervorgerufene Amplitudenreduktion und auch den reduzierenden Effekt der beiden Transport-Inhibitoren. In nachfolgenden Experimenten mit dem spezifischen Gruppe II mGluR-Antagonisten EGLU konnte dieser zwar die durch L-trans-2,4-PDC hervorgerufene Wirkung verhindern, nicht aber den durch DL-TBOA vermittelten Effekt, was auf eine Aktivierung von Gruppe I mGluRs hinweist. Zusätzlich führte die Applikation von DL-TBOA zu einer signifikanten Veränderung des Doppelpuls-Index, was auf einen präsynaptischen Wirkmechanismus hinweist. Die Applikation von L-trans-2,4-PDC hingegen hatte keinen Effekt auf den Doppelpuls-Index. Die Ergebnisse der vorliegenden Arbeit sprechen dafür, daß beide Transport-Inhibitoren die erregende synaptische Transmission über eine Aktivierung präsynaptischer metabotroper Glutamatrezeptoren der Gruppen I und II hemmen. Dabei konnte festgestellt werden, daß diese Hemmung unter Applikation von DL-TBOA die präsynaptische Transmitterausschüttung über einen negativen Rückkopplungsmechanismus durch Aktivierung von Gruppe I mGluRs vermindert, während L-trans-2,4-PDC seine Wirkung vor allem über eine Aktivierung der Gruppe II vermittelt. Dabei kann davon ausgegangen werden, daß L-trans-2,4-PDC in der benutzten Konzentration die mGluRs der Gruppe II direkt aktivieren kann und der Effekt nicht nur präsynaptisch vermittelt wird. / Glutamate is the primary excitatory neurotransmitter in the mammalian central nervous system. The precise control of extracellular glutamate is crucial for the maintenance of normal synaptic transmission and the prevention of excitotoxicity. High-affinity glutamate transporters ensure termination of glutamatergic neurotransmission and keep the synaptic glutamate concentration below excitotoxic levels. In layer III, a region that is especially prone to cell damage in Alzheimer's disease, schizophrenia and epilepsy, and layer V of the medial entorhinal cortex (mEC) effects of blocking glutamate uptake on excitatory synaptic transmission were studied. Extracellular recordings in rat brain slices revealed that application of glutamate uptake inhibitors significantly reduced stimulus-induced negative field potentials in both, layer III and V of the mEC. This effect showed no significant differences in both layers suggesting a similar glutamate regulation in layer III and V. Therefore, only layer III neurons of the mEC were used for the subsequent intracellular and patch-clamp recordings. Two competitive glutamate transporter antagonists, DL-TBOA and L-trans-2,4-PDC, reduced the amplitude of pharmacologically isolated EPSPs/EPSCs without changing the time course of the events. This effect was mimicked by trans-(±)-ACPD, an agonist of group I and II metabotropic glutamate receptors (mGluRs). The competitive group I and II mGluR antagonist MCPG blocked the depression of the EPSC amplitude induced by trans-(±)-ACPD and also masked the effect of either DL-TBOA or L-trans-2,4-PDC. Furthermore, EGLU, which selectively antagonizes group II mGluRs, masked the effect of L-trans-2,4-PDC but not that of DL-TBOA, indicating an involvement of group I mGluRs in the latter case. Finally, DL-TBOA significantly enhanced the paired-pulse index, suggesting a presynaptic mechanism for the depression of EPSP/EPSC amplitude, whereas application of L-trans-2,4-PDC had no significant effect on the paired-pulse behaviour. The present study shows that both transport inhibitors depress pharmacologically isolated EPSPs/EPSCs in layer III neurons of the mEC in combined entorhinal-hippocampal slices. This effect seems to be mediated via activation of different groups of mGluRs. The results suggest that DL-TBOA causes a negative feedback on glutamate release via indirect activation of presynaptic group I mGluRs, possibly due to an accumulation of glutamate, whereas application of L-trans-2,4-PDC most likely leads to an activation of presynaptic group II mGluRs reducing Ca2+-independent release. The latter might be due to a direct action of L-trans-2,4-PDC at these receptors. The present data suggest that blockade of glutamate transport in the mEC does not lead to an excessive accumulation of glutamate because of a counteractive autoinhibiting mechanism.

The transporter systems of Oliver and Ventura and the localities of Chermak are classes of algebraic structures that model the 𝑝-local structures of finite groups. Other than the transporter categories and localities of finite groups, important examples include centric, quasicentric, and subcentric linking systems for saturated fusion systems. These examples are, however, not defined in general on the full collection of subgroups of the Sylow group. We study here punctured groups, a short name for transporter systems or localities on the collection of nonidentity subgroups of a finite 𝑝-group. As an application of the existence of a punctured group, we show that the subgroup homology decomposition on the centric collection is sharp for the fusion system. We also prove a Signalizer Functor Theorem for punctured groups and use it to show that the smallest Benson–Solomon exotic fusion system at the prime 2 has a punctured group, while the others do not. As for exotic fusion systems at odd primes 𝑝, we survey several classes and find that in almost all cases, either the subcentric linking system is a punctured group for the system, or the system has no punctured group because the normalizer of some subgroup of order 𝑝 is exotic. Finally, we classify punctured groups restricting to the centric linking system for certain fusion systems on extraspecial 𝑝-groups of order 𝑝3.

Little is still known about what allows mature Arabidopsis thaliana (Arabidopsis) plants to respond with an Age-Related Resistance response (ARR). To better understand how mature plants initiate and establish ARR, gene expression in the leaves of young and mature plants responding to Pseudomonas syringae pv. tomato (Pst) was investigated using RNA-sequencing analysis. Genes involved in the biosynthesis of N-hydroxypipecolic acid (NHP) were upregulated in ARR-responding leaves leading to the idea that NHP, a signaling molecule in Systemic AcquiredResistance (SAR) may also be required for ARR. The ARR response was examined in NHP biosynthesis mutants and revealed that NHP biosynthesis is required for ARR. During ARR, NHP biosynthesis mutants were also shown to accumulate less salicylic acid (SA) compared to wild-type leaves in response to Pst. Healthy untreated leaves had modest accumulation of NHP and modest expression of several cell-surface receptors was observed compared to the healthy untreated leaves of young plants, suggesting that ARR competence in mature untreated plants involves a primed/immune ready state similar to what is observed in systemic leaves of plants induced for SAR in a local leaf. The ARR response also requires the accumulation of intercellular SA which is involved in inhibiting biofilm-like aggregate formation of Pst in mature plant leaves. To understand how SA is transported from the cytosol to the intercellular space during ARR, the ARR response of the PDR-type transporter mutants pdr8-4 and pdr12-3 was examined. The pdr8-4 pdr12-3 double mutant was partially ARR-defective and SA accumulation in leaf intercellular spaces was reduced by ~50% compared to wild-type mature plants during ARR, demonstrating that PDR8 and PDR12 are required for the intercellular localisation of SA during ARR. To obtain evidence that PDR8 and PDR12 act as transporters of SA, SA transporter assays were performed with yeast expressing PDR8 and PDR12. PDR8- and PDR12-expressing yeast accumulated less intracellular SA than empty vector containing yeast cells, suggesting that PDR8 and PDR12 act as SA transporters. Together, this work found ARR shared signaling components with SAR and found additional support for SA as an antimicrobial and signaling molecule during ARR. / Thesis / Doctor of Science (PhD)

Eisenmangel ist ein weltweites Ernährungsproblem für Pflanzen und allen von Ihnen abhängigen Sekundärkonsumenten. Er reduziert den Ertrag, die Qualität und Produktivität von z.B. Kulturpflanzen, was wiederum zu Mangelerscheinungen beim Menschen führen kann. Die Nahrungsmittelforschung hat ein großes ökonomisches und wirtschaftliches Interesse daran, die Eisenverfügbarkeit und -Aufnahme der Pflanzen zu erhöhen. In der vorliegenden Arbeit wurde eine kleine Familie von fünf (VTL1-5) neuen potentiellen Eisentransportern in Arabidopsis thaliana identifiziert und charakterisiert und somit ein weiterer Baustein zu der Aufklärung der Eisenhomöostase hinzugefügt. Bei den fünf Transportern handelt es sich um CCC1-like Proteine, von denen vier (VTL1-3 und 5) eine eisenabhängig regulierte Expression zeigen. Für VTL1 kann mittels Protein-tag Markierung sehr überzeugend eine Lokalisation in der Vakuolenmembran und ein damit verbundener Eisentransport in die Vakuole, analog zur Funktion von VIT1, gezeigt werden. Da vermutlich ein knockout von VTL1 zur Embryo Lethalität führt und auch die vit1-1 Mutante einen sehr verkümmerten Phänotyp unter Eisenmangel zeigt, scheinen beide Proteine getrennt voneinander an verschiedenen Schlüsselpositionen im Eisenhaushalt zu wirken. Auch für VTL2 und VTL5 kann eine Lokalisation an der Vakuolenmembran und der damit verbundene Eisenimport postuliert werden. Die heterologe Expression aller drei Gene in ∆ccc1 Zellen führt zur Erhöhung der vakuolären Eisenkonzentration. Für VTL4 wird mittels Protein-tag Markierung eine Lokalisation an der Plasmamembran mit einer Exportfunktion vorgeschlagen. VTL3 und VTL4 heterolog exprimierende ∆ccc1 Hefe-Zellen weisen einen geringeren Eisengehalt als Kontrollzellen auf. Alle fünf Proteine sind in der Lage sowohl den Mutanten-Phänotyp der ∆ccc1 Hefe-Mutante, wie auch der Arabidopsis vit1-1 und nramp3/nramp4 Doppelmutante zu komplementieren. Anhand dieser Tatsachen konnte die Eisentransportfähigkeit bewiesen werden. / Iron deficiency is a worldwide nutritional problem for plants and in general all heterotrophic organisms. Iron deficiency reduces crop productivity, quality and yield, which in consequence lead to iron deficiency symptoms in humans. Because approximately 50 % of the global human caloric intake is derived from a cereal grain diet, it is not surprising that the emphasis of nutrition research is on uptake, transport and storage of iron in plants, specifically in seeds. In this doctoral thesis a small family of five potential iron transporters (VTL1-5) in Arabidopsis thaliana has been identified and characterized. These five transporters are CCC1-like proteins, four of which (VTL1-3, 5) show a pattern of iron-dependent expression. Through the use of a protein tag, VTL1 is shown to be localized on the vacuolar membrane and associated with import of iron into the vacuole. In this respect VTL1 displays an analogous function to VIT1. Since the knockout of VTL1 likely leads to embryo lethality and seedlings of the vit1-1 mutant display an ephemeral phenotype caused by iron deficiency, both proteins seem to uniquely influence the iron homeostasis. As for VTL1 both VTL2 and VTL5 are localized on the vacuolar membrane and catalyze iron import. The heterologous expression of all three genes in ∆ccc1 cells leads to an increased vacuolar iron concentration. In contrast, VTL3 and VTL4 may function as iron exporters and play possibly roles in xylem loading. This conclusion is supported by the facts that a mCherry-VTL4 signal is localized to the plasma membrane of tobacco leaf cells and that ∆ccc1 cells in which VTL3 and VTL4 are heterologous expressed, show a decreased iron content compared to control cells. All five proteins are able to complement the ∆ccc1 yeast mutant and the two Arabidopsis vit1-1 and nramp3/nramp4 mutant phenotypes, thereby demonstrating a function in iron transport.

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