Strategies and mechanisms of cellular interaction between the parasitic weed Orobanche cumana WALLR. and its host Helianthus annuus L.

Sunflower broomrape, Orobanche cumana WALLR., is a root parasitic plant causing considerable yield losses in sunflower cultivation in Europe, North Africa and Asia. Comprehensive knowledge about early interaction stages between host and parasite is necessary to find new ways of controlling this weed. In this thesis, three aspects regarding the biology of O. cumana were studied: 1) the chemotropism of O. cumana germtubes which bend towards the host root, 2) the development of O. cumana on resistant and susceptible sunflower lines and 3) the development of the phloem connection between the O. cumana haustorium and the sunflower host root. Sesquiterpene lactones in sunflower root exudates act as germination stimulants for O. cumana. As sesquiterpene lactones are known inhibitors of plant elongation growth and seem to play a role in the phototropic curvature of sunflower hypocotyls, a chemotropism bioassay on water agar was established to test if they also serve as chemotropic signals for the host-finding of O. cumana germtubes. When sesquiterpene lactone containing sunflower root exudate, sunflower seed oil extract or the sesquiterpene lactone reference costunolide were applied on filter discs, 70 % of the germtubes showed orientation towards them. The artificial strigolactone GR24, however, did not induce chemotropism. A concentration gradient of sesquiterpene lactones exudated from the host root is likely to be responsible for a stronger inhibition of elongation growth on the host-facing flank of the germtube. This would confer a double role of sesquiterpene lactones from root exudates in the sunflower-broomrape-interaction, namely as germination stimulants and as chemotropic signals. One way of controlling O. cumana is the cultivation of resistant sunflower lines. However, this resistance is rapidly overcome by more aggressive pathotypes of the parasite. Therefore, the resistance or tolerance reaction of the sunflower genotype T35001 was investigated in comparison to six other sunflower genotypes with different resistance characteristics. The development of O. cumana was monitored in a root chamber system which allowed permanent assessment of germination, attachment and tubercle formation in the different host-parasite-combinations. All seven tested sunflower lines induced germination and attachment of O. cumana, independent of the expected resistance or susceptibility of the host. A difference between compatibility or incompatibility of the interactions was only observed at the tubercle stage. On T35001, tubercles never occurred, neither in root chamber nor in pot experiments. To find out why the development stopped before the tubercle stage, samples of sunflower roots with attached O. cumana seedlings were analysed by bright field-, fluorescence- and transmission electron microscopy. Histological studies revealed that O. cumana penetrated the host root, but never reached the hosts vascular bundle. The root cortex cells surrounding the Orobanche haustorium showed no ultrastructural changes such as cell wall thickening. Fluorescence microscopy revealed no callose depositions or signs of phytoalexin release. However, ultrastructural examination of the host-parasite-interface showed degeneration processes in both cortex and haustorial cells. Cortex cells were flooded with bacteria, haustorium cells showed degeneration of cytoplasm and nuclei. The resistance mechanism that prevented further development of the O. cumana haustorium did not express itself in a histologically visible way. As holoparasite, O. cumana acquires its entire demand for water, minerals and organic nutrients from the hosts vascular system. The development of the xylem connection between O. cumana and sunflower had previously been reported, but the phloem connection is far more relevant for the parasite in terms of organic nutrients. Accordingly, the ultrastructure of the phloem connection between the haustorium of young O. cumana tubercles and the sunflower root was examined. Parasite and host tissues were intermingled at the contact site and difficult to distinguish, but sieve-tube elements of O. cumana and sunflower could be differentiated according to their plastid ultrastructure. While sieve-element plastids of O. cumana were larger, often irregular in shape and contained few, small starch inclusions, sieve-element plastids of the host were significantly smaller, always round with more and larger starch inclusions. This made it possible to trace the exact contact site of host and parasite sieve elements to show a direct symplastic phloem connection between the two species. The interspecific sieve plate showed more callose on the host side. This allowed detection of newly formed plasmodesmata between host sieve-tube elements and parenchymatic parasite cells, thus showing that undifferentiated cells of the parasite can connect to fully differentiated sieve elements of sunflower.Die Sonnenblumen-Sommerwurz, Orobanche cumana WALLR., eine wurzelparasitische Pflanze, verursacht beträchtliche Ernteausfälle im Sonnenblumenanbau in Europa, Nordafrika und Asien. Umfassendes Wissen über frühe Interaktionsstadien zwischen Wirt und Parasit sind nötig, um neue Wege zur Bekämpfung des Parasiten zu finden. In dieser Arbeit wurden drei Aspekte der Biologie von O. cumana untersucht: 1) Der Chemotropismus von O. cumana-Keimschläuchen hin zur Wirtswurzel; 2) die Entwicklung von O. cumana auf resistenten und suszeptiblen Sonnenblumen-Linien; und 3) die Entwicklung der Phloem-Verbindung zwischen dem O. cumana-Haustorium und der Sonnenblumen-Wirtswurzel. Sesquiterpenlactone in Wurzelexsudaten der Sonnenblume induzieren die Keimung von O. cumana-Samen, sind auch als Inhibitoren des pflanzlichen Streckungswachstums bekannt und scheinen eine Rolle in der phototropen Krümmung von Sonnenblumen-Hypokotylen zu spielen. Um zu testen, ob sie auch als chemotrope Signale für die Wirtsfindung von O. cumana-Keimschläuchen verantwortlich sind, wurde ein Chemotropismus-Biotest auf Wasseragar entwickelt. Wenn sesquiterpenlactonhaltiges Sonnenblumenwurzelexsudat, Sonnenblumenölextrakt oder die Sesquiterpenlacton-Referenzsubstanz Costunolid auf Filterplättchen eingesetzt wurden, wuchsen 70 % der Keimschläuche auf diese zu. Das künstliche Strigolacton GR24 induzierte keinen Chemotropismus. Ein Konzentrationsgradient der von der Wirtswurzel exsudierten Sesquiterpenlactone scheint für eine stärkere Inhibierung des Streckungswachstums auf der dem Wirt zugewandten Keimschlauchseite verantwortlich zu sein. Dies würde den Sesquiterpenlactonen in Sonnenblumenwurzelexsudaten eine Doppelrolle in der Interaktion mit O. cumana zukommen lassen, nämlich als Keimstimulanzien und als Signale für den Chemotropismus. O. cumana kann durch den Anbau resistenter Sonnenblumenlinien bekämpft werden. Diese Resistenz wird jedoch von neuen, aggressiveren Pathotypen des Parasiten überwunden. Ziel war es daher, Resistenz- oder Toleranzreaktionen des Sonnenblumen-Genotyps T35001 im Vergleich zu sechs anderen Sonnenblumengenotypen mit unterschiedlichen Resistenzcharakteristika zu untersuchen. Ein Wurzelkammersystem erlaubte die kontinuierliche Beobachtung der Keimung, Anlagerung und Tuberkelbildung bei den unterschiedlichen Wirt-Parasit-Kombinationen. Alle sieben getesteten Sonnenblumenlinien induzierten die Keimung und Anlagerung von O. cumana, unabhängig von deren erwarteter Suszeptibilität oder Resistenz. Ein Unterschied zwischen kompatiblen und inkompatiblen Interaktionen wurde erst im Tuberkelstadium sichtbar. Auf den Wurzeln von T35001 entwickelten sich nie Tuberkel, weder in Wurzelkammer- noch in Topfversuchen. Warum die Entwicklung von O. cumana vor dem Tuberkelstadium stoppte, wurde licht-, fluoreszenz- und transmissionselektronenmikroskopisch untersucht. Die histologischen Studien zeigten, dass der Parasit zwar in die Wirtswurzel eindrang, aber nicht den Zentralzylinder erreichte. Die Wurzelrindenzellen, die das Orobanche-Haustorium umgaben, wiesen keine ultrastrukturellen Veränderungen auf, wie beispielsweise Zellwandverdickungen. Weder Kalloseablagerungen noch Zeichen für Phytoalexinproduktion waren mittels Fluoreszenzmikroskopie sichtbar. Ultrastrukturelle Untersuchungen der Kontaktstellen von Wirt und Parasit zeigten jedoch Degenerationsprozesse sowohl in den Zellen der Wurzelrinde als auch in denen des Haustoriums. Die Wurzelzellen waren voller Bakterien, auch Zellkerne und Cytoplasma der Haustorienzellen erschienen degeneriert. Der Resistenzmechanismus, der die weitere Entwicklung des Haustoriums verhinderte, war histologisch nicht sichtbar. Als Holoparasit deckt O. cumana seinen gesamten Bedarf an Wasser, Mineralien und organischen Nährstoffen aus dem Leitbündelsystem des Wirtes. In dieser Arbeit wurde zum ersten Mal die Ultrastruktur der Phloemverbindung zwischen dem Haustorium des jungen Tuberkels und der Wirtswurzel untersucht. Die Gewebe von Wirt und Parasit waren an den Kontaktstellen schwer zu unterscheiden, doch die Siebröhrenelemente konnten aufgrund ihrer Plastidenultrastruktur eindeutig zugeordnet werden. Während die Siebröhrenplastiden von O. cumana meist größer und unregelmäßig geformt waren und wenige kleine Stärkeeinschlüsse enthielten, waren die der Sonnenblume signifikant kleiner, immer rundlich und besaßen mehr und größere Stärkeeinschlüsse. Dies erlaubte es, die exakte Anschlussstelle zwischen Wirt und Parasit zu finden. Direkte symplastische Phloemverbindungen wurden zwischen den beiden Arten entdeckt. Die interspezifische Siebplatte wies auf der Wirtsseite stets mehr Kallose auf und ermöglichte somit die Identifizierung neu gebildeter Plasmodesmen zwischen parenchymatischen Haustorienzellen und Siebröhren der Sonnenblume. Undifferenzierte Orobanche-Zellen konnten sich also mit vollständig differenzierten Siebröhrenelementen der Sonnenblume verbinden

Three-step economical and green alternative to Donepezil intermediate

A three step economical and green alternative has been developed for the synthesis of the Donepezil intermediate. Donepezil is an acetylcholinesterase inhibitor used to improve cognitive functions in Alzheimer\u27s disease (AD) patients. AD is a progressive neurodegenerative disorder characterized by the loss of memory and dementia and has been shown to cause the death of cholinergic neurons and a decline in acetylcholine. Multiple studies showed that the use of anticholinergic agents cause amnesia and learning disabilities which confirm the importance of acetylcholine against dementia. The use of acetylcholinesterase inhibitor inhibits the enzyme acetylcholinesterase increasing, thus, the levels of acetylcholine. The three steps synthesis proposed involve the conversion of 3,4-dimethoxycinnamic acid to 3-phenylpropionic acid via Pd/C catalysis followed by the conversion of 3-phenylpropionic acid to 5,6-dimethoxy-1-inandone via intramolecular Friedel-Craft acylation using ethyl acetate for extraction as a green alternative to dichloromethane. 5,6-dimethoxy-1-inandone and 4-Pyridinecarboxaldehyde were added together to form our Donepezil intermediate

Aufbau und Transformation Si-stereogener Verbindungen

Das Ziel dieser Arbeit war es, Si-stereogene Organosilane über substratinduzierte diastereoselektive Synthesen mit hohen Diastereomerenüberschüssen zu erzeugen, und die Reaktionen stereochemisch zu untersuchen. Im direkten Anschluss erfolgte die intensive Untersuchung des stereochemischen Ver¬laufs der Substitution der verbliebenen funktionellen Gruppen. Nach Synthese der Si-stereogenen Silane erfolgte die konfigurelle Aufklärung über die Co-Kristallisation mit der Halogenbrücken-Methode als nicht-kovalente Derivatisierung. Neben der Bestimmung der absoluten Konfigurationen der stereogenen Siliciumzentren konnte die Halogenbrücken-Methode auch zur Strukturaufklärung achiraler Verbindungen erfolgreich genutzt werden. Die substratinduzierten diastereoselektiven Synthesen, basierend auf einem chiralen Aminrückgrat, lieferten bei der nucleophilen Substitution von Dimethoxysilanen mit Lithiumalkylen Si-stereogene Monomethoxysilane mit guten bis exzellenten Diastereomerenverhältnissen (bis > 99:1). Die wechselseitig komplementären Synthesen zeigen eine klare Stereodivergenz, wodurch experimentell eine kinetisch kontrollierte Reaktionsführung belegt ist. Die Si-stereogenen Monomethoxysilane wurden in einem weiteren Schritt in Studien zur Trans-formation der verbliebenen Methoxygruppe durch Substitution mit verschiedenen Nucleophilen eingesetzt. Die nucleophile Substitution der Monomethoxysilane verläuft stereospezifisch unter Retention der Konfiguration am Silicium für primäre Lithiumalkyle, heterozyklische Lithiumalkyle und Hydride ab. Durch die Kombination der experimentellen Beobachtungen mit quantenchemischen Studien konnten Mechanismushypothesen aufgestellt werden

Visualizing Entanglement in multi-Qubit Systems

In the field of quantum information science and technology, the representation and visualization of quantum states and related processes are essential for both research and education. In this context, a focus especially lies on ensembles of few qubits. There exist many powerful representations for single-qubit and multi-qubit systems, such as the famous Bloch sphere and generalizations. Here, we utilize the dimensional circle notation as a representation of such ensembles, adapting the so-called circle notation of qubits and the idea of representing the n-particle system in an n-dimensional space. We show that the mathematical conditions for separability lead to symmetry conditions of the quantum state visualized, offering a new perspective on entanglement in few-qubit systems and therefore on various quantum algorithms. In this way, dimensional notations promise significant potential for conveying nontrivial quantum entanglement properties and processes in few-qubit systems to a broader audience, and could enhance understanding of these concepts as a bridge between intuitive quantum insight and formal mathematical descriptions.Comment: 22 pages, 20 figure

Arterial Catheters as a Source of Bloodstream Infection: A Systematic Review and Meta-Analysis*

Objective: Catheter-related bloodstream infections are associated with significant costs and adverse consequences. Arterial catheters are commonly used in the critical care setting and are among the most heavily manipulated vascular access devices. We sought to evaluate the prevalence of arterial catheter-related bloodstream infection. Data Sources: PubMed, CinAHL, EMBASE, and Web of Science. Study Selection: Included studies reported prevalence rate of catheter-related bloodstream infection for arterial catheters used for critical illness or postoperative monitoring. For the purposes of this study, catheter-related bloodstream infection was defined as positive blood culture collected from an arterial catheter and from the periphery with the same organism in a patient demonstrating systemic signs of sepsis. Data Extraction: The study population, site of insertion, antiseptic preparation, catheter days, and prevalence of catheter-related bloodstream infection were abstracted. When data were not available, authors were contacted for further information. Data Synthesis: Forty-nine studies met criteria including 222 cases of arterial catheter-related bloodstream infection in 30,841 catheters. Pooled incidence was 3.40/1,000 catheters or 0.96/1,000 catheter days. Prevalence was considerably higher in the subgroup of studies that cultured all catheters (1.26/1,000 catheter days) compared with those studies that cultured only when the arterial catheter was suspected as the source for the catheter-related bloodstream infection (0.70/1,000 catheter days). Pooled data also found a significantly increased risk of infection for femoral site of insertion compared with radial artery for arterial catheter placement ( relative risk, 1.93; 95% CI, 1.32-2.84; p = 0.001) Conclusions: Arterial catheters are an underrecognized cause of catheter-related bloodstream infection. Pooled incidence when catheters were systematically cultured and correlated to blood culture results indicated a substantial burden of arterial catheter-related bloodstream infection. Selection of a radial site over a femoral site will help reduce the risk of arterial catheter-related bloodstream infection. Future studies should evaluate technologies applied to preventing central venous catheter-related bloodstream infection to arterial catheters as well. (Crit Care Med 2014; 42:1334-1339 Key Words: arterial catheterization; catheter-related infections; critical care; meta-analysis; nosocomial infections; peripheral; prevalence A rterial catheters are essential for hemodynamic monitoring in critically ill patients. Each year, approximately eight million arterial catheters are placed in the United States (1, 2). One of the most serious complications of all intravascular devices is catheter-related bloodstream infection (BSI) (3). Arterial catheter-related BSIs (CRBSIs) are associated with serious complications, including site pseudoaneurysms (4), septic thromboarteritis (5), and arterial rupture (6). Arterial CRBSIs carry a considerable risk of morbidity and mortality, as complications often require surgical intervention. The risk of endemic arterial CRBSI is unclear and has ranged from 0% to 4% in published studie

Sensitivity to heat in MS patients: a factor strongly influencing symptomology - an explorative survey

<p>Abstract</p> <p>Background</p> <p>Many individuals diagnosed with Multiple Sclerosis (MS) are sensitive to increased body temperature, which has been recognized as correlating with the symptom of fatigue. The need to explore this association has been highlighted. The aim of this study was to investigate the occurrence of heat sensitivity and its relations to disease course, disability, common MS-related symptoms and ongoing immunosuppressive treatments among individuals 65 years of age or younger diagnosed with MS.</p> <p>Methods</p> <p>A cross-sectional designed survey was undertaken. A questionnaire was sent to MS-patients with an Expanded Disability Status Score (EDSS) in the interval of 0-6.5 and who were between 20 and 65 years of age, living in an eastern region of Sweden (n = 334). Besides occurrence of heat sensitivity (Yes/No) and corresponding questions, the Fatigue Severity Scale (FSS), the MS-related symptom checklist and the Perceived Deficit Questionnaire (PDQ) were included. Data were analysed in relation to data level using Chi-square, Mann Whitney U-test, and Student's t-test. Pearson's and Spearman's correlations were calculated. In the logistic regression analyses (enter) dichotomized MS-symptoms were used as dependent variables, and EDSS, disease-course, time since onset, heat-sensitivity, age and sex (female/male) were independent variables. In the linear regression analyses, enter, mean FSS and summarized PDQ were entered as dependent variables and EDSS, disease-course, time since onset, heat sensitivity, age and sex (female/male) were independent variables.</p> <p>Results</p> <p>Of the responding patients (n = 256), 58% reported heat sensitivity. The regression analyses revealed heat sensitivity as a significant factor relating not only to fatigue (p < 0.001), but also to several other common MS symptoms such as pain (p < 0.001), concentration difficulties (p < 0.001), and urination urgency (p = 0.009).</p> <p>Conclusions</p> <p>Heat sensitivity in MS patients is a key symptom that is highly correlated with disabling symptoms such as fatigue, pain, concentration difficulty and urination urgency.</p

A chemical survey of exoplanets with ARIEL

Thousands of exoplanets have now been discovered with a huge range of masses, sizes and orbits: from rocky Earth-like planets to large gas giants grazing the surface of their host star. However, the essential nature of these exoplanets remains largely mysterious: there is no known, discernible pattern linking the presence, size, or orbital parameters of a planet to the nature of its parent star. We have little idea whether the chemistry of a planet is linked to its formation environment, or whether the type of host star drives the physics and chemistry of the planet’s birth, and evolution. ARIEL was conceived to observe a large number (~1000) of transiting planets for statistical understanding, including gas giants, Neptunes, super-Earths and Earth-size planets around a range of host star types using transit spectroscopy in the 1.25–7.8 μm spectral range and multiple narrow-band photometry in the optical. ARIEL will focus on warm and hot planets to take advantage of their well-mixed atmospheres which should show minimal condensation and sequestration of high-Z materials compared to their colder Solar System siblings. Said warm and hot atmospheres are expected to be more representative of the planetary bulk composition. Observations of these warm/hot exoplanets, and in particular of their elemental composition (especially C, O, N, S, Si), will allow the understanding of the early stages of planetary and atmospheric formation during the nebular phase and the following few million years. ARIEL will thus provide a representative picture of the chemical nature of the exoplanets and relate this directly to the type and chemical environment of the host star. ARIEL is designed as a dedicated survey mission for combined-light spectroscopy, capable of observing a large and well-defined planet sample within its 4-year mission lifetime. Transit, eclipse and phase-curve spectroscopy methods, whereby the signal from the star and planet are differentiated using knowledge of the planetary ephemerides, allow us to measure atmospheric signals from the planet at levels of 10–100 part per million (ppm) relative to the star and, given the bright nature of targets, also allows more sophisticated techniques, such as eclipse mapping, to give a deeper insight into the nature of the atmosphere. These types of observations require a stable payload and satellite platform with broad, instantaneous wavelength coverage to detect many molecular species, probe the thermal structure, identify clouds and monitor the stellar activity. The wavelength range proposed covers all the expected major atmospheric gases from e.g. H2O, CO2, CH4 NH3, HCN, H2S through to the more exotic metallic compounds, such as TiO, VO, and condensed species. Simulations of ARIEL performance in conducting exoplanet surveys have been performed – using conservative estimates of mission performance and a full model of all significant noise sources in the measurement – using a list of potential ARIEL targets that incorporates the latest available exoplanet statistics. The conclusion at the end of the Phase A study, is that ARIEL – in line with the stated mission objectives – will be able to observe about 1000 exoplanets depending on the details of the adopted survey strategy, thus confirming the feasibility of the main science objectives.Peer reviewedFinal Published versio

Beyond the Symptom: The Biology of Fatigue

A workshop titled Beyond the Symptom: The Biology of Fatigue was held virtually September 27-28, 2021. It was jointly organized by the Sleep Research Society and the Neurobiology of Fatigue Working Group of the NIH Blueprint Neuroscience Research Program. For access to the presentations and video recordings, see: https://neuroscienceblueprint.nih.gov/about/event/beyond-symptom-biology-fatigue. The goals of this workshop were to bring together clinicians and scientists who use a variety of research approaches to understand fatigue in multiple conditions and to identify key gaps in our understanding of the biology of fatigue. This workshop summary distills key issues discussed in this workshop and provides a list of promising directions for future research on this topic. We do not attempt to provide a comprehensive review of the state of our understanding of fatigue, nor to provide a comprehensive reprise of the many excellent presentations. Rather, our goal is to highlight key advances and to focus on questions and future approaches to answering them

Motor, cognitive and mobility deficits in 1000 geriatric patients : protocol of a quantitative observational study before and after routine clinical geriatric treatment – the ComOn-study

© The Author(s). 2020 Open Access. This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.Background: Motor and cognitive deficits and consequently mobility problems are common in geriatric patients. The currently available methods for diagnosis and for the evaluation of treatment in this vulnerable cohort are limited. The aims of the ComOn (COgnitive and Motor interactions in the Older populatioN) study are (i) to define quantitative markers with clinical relevance for motor and cognitive deficits, (ii) to investigate the interaction between both motor and cognitive deficits and (iii) to assess health status as well as treatment outcome of 1000 geriatric inpatients in hospitals of Kiel (Germany), Brescia (Italy), Porto (Portugal), Curitiba (Brazil) and Bochum (Germany). Methods: This is a prospective, explorative observational multi-center study. In addition to the comprehensive geriatric assessment, quantitative measures of reduced mobility and motor and cognitive deficits are performed before and after a two week's inpatient stay. Components of the assessment are mobile technology-based assessments of gait, balance and transfer performance, neuropsychological tests, frailty, sarcopenia, autonomic dysfunction and sensation, and questionnaires to assess behavioral deficits, activities of daily living, quality of life, fear of falling and dysphagia. Structural MRI and an unsupervised 24/7 home assessment of mobility are performed in a subgroup of participants. The study will also investigate the minimal clinically relevant change of the investigated parameters. Discussion: This study will help form a better understanding of symptoms and their complex interactions and treatment effects in a large geriatric cohort.info:eu-repo/semantics/publishedVersio