oalib

Publish in OALib Journal

ISSN: 2333-9721

APC: Only $99

Submit

Search Results: 1 - 10 of 1936 matches for " Uwe Ludewig "
All listed articles are free for downloading (OA Articles)
Page 1 /1936
Display every page Item
The genome of the endophytic bacterium H. frisingense GSF30T identifies diverse strategies in the Herbaspirillum genus to interact with plants
Daniel Straub,Anton Hartmann,Uwe Ludewig
Frontiers in Microbiology , 2013, DOI: 10.3389/fmicb.2013.00168
Abstract: The diazotrophic, bacterial endophyte Herbaspirillum frisingense GSF30T has been identified in biomass grasses grown in temperate climate, including the highly nitrogen-efficient grass Miscanthus. Its genome was annotated and compared with related Herbaspirillum species from diverse habitats, including H. seropedicae, and further well-characterized endophytes. The analysis revealed that Herbaspirillum frisingense lacks a type III secretion system that is present in some related Herbaspirillum grass endophytes. Together with the lack of components of the type II secretion system, the genomic inventory indicates distinct interaction scenarios of endophytic Herbaspirillum strains with plants. Differences in respiration, carbon, nitrogen and cell wall metabolism among Herbaspirillum isolates partially correlate with their different habitats. Herbaspirillum frisingense is closely related to strains isolated from the rhizosphere of phragmites and from well water, but these lack nitrogen fixation and metabolism genes. Within grass endophytes, the high diversity in their genomic inventory suggests that even individual plant species provide distinct, highly diverse metabolic niches for successful endophyte-plant associations.
H+-Independent Glutamine Transport in Plant Root Tips
Huaiyu Yang,Martin Bogner,York-Dieter Stierhof,Uwe Ludewig
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0008917
Abstract: Glutamine is one of the primary amino acids in nitrogen assimilation and often the most abundant amino acid in plant roots. To monitor this important metabolite, a novel genetically encoded fluorescent FRET-reporter was constructed and expressed in Arabidopsis thaliana. As a candidate for the glutamine fluxes, the root tip localized, putative amino acid transporter CAT8 was analyzed and heterologously expressed in yeast and oocytes.
Two putative-aquaporin genes are differentially expressed during arbuscular mycorrhizal symbiosis in Lotus japonicus
Marco Giovannetti, Raffaella Balestrini, Veronica Volpe, Mike Guether, Daniel Straub, Alex Costa, Uwe Ludewig, Paola Bonfante
BMC Plant Biology , 2012, DOI: 10.1186/1471-2229-12-186
Abstract: A phylogenetic analysis has shown that the two putative aquaporins belong to different functional families: NIPs and XIPs. Transcriptomic experiments have shown the independence of their expression from their nutritional status but also a close correlation with mycorrhizal and rhizobial interaction. Further transcript quantification has revealed a good correlation between the expression of one of them, LjNIP1, and LjPT4, the phosphate transporter which is considered a marker gene for mycorrhizal functionality. By using laser microdissection, we have demonstrated that one of the two genes, LjNIP1, is expressed exclusively in arbuscule-containing cells. LjNIP1, in agreement with its putative role as an aquaporin, is capable of transferring water when expressed in yeast protoplasts. Confocal analysis have demonstrated that eGFP-LjNIP1, under its endogenous promoter, accumulates in the inner membrane system of arbusculated cells.Overall, the results have shown different functionality and expression specificity of two mycorrhiza-inducible aquaporins in L. japonicus. One of them, LjNIP1 can be considered a novel molecular marker of mycorrhizal status at different developmental stages of the arbuscule. At the same time, LjXIP1 results to be the first XIP family aquaporin to be transcriptionally regulated during symbiosis.Knowledge has increased concerning the fact that a plant does not act as an individual on its own, but as an actor in a vast stage populated by bacteria, fungi and other microorganisms [1-3]. Arbuscular mycorrhizal (AM) fungi represent one of the most important components of the complex root-plant microbiome, since they are present in about 80% of vascular plants. They supply the plant with phosphate, nitrogen, mineral salts and water, and they guarantee a more extensive protection from biotic and abiotic stresses at both local and systemic level. On the other hand, the plant allows the fungus to access the photosynthetic carbon-compounds [4].A partly know
Rhesus factors and ammonium: a function in efflux?
Uwe Ludewig, Nico von Wirén, Doris Rentsch, Wolf B Frommer
Genome Biology , 2001, DOI: 10.1186/gb-2001-2-3-reviews1010
Abstract: Ammonium is the preferred nitrogen source of bacteria and fungi, and plants acquire nitrogen from the soil in the form of ammonium [1]. In animals and humans, assimilated forms of nitrogen - amino acids - are much preferred for nutrition, and, in the case of ammonotelic animals, ammonium is used for the excretion of nitrogen instead. In the human kidney, ammonium is produced, reabsorbed and excreted as a means to maintain pH balance and to get rid of surplus inorganic nitrogen. Whether ammonium transport also has a role in the pH regulation of other organs is not known and the molecular mechanisms were not, up to now, understood.In aqueous solution, ammonium (NH4+) is in equilibrium with ammonia (NH3) with a pKa of 9.25. Thus, at typical cytosolic pH, approximately 99% is present in the cationic form. Ammonia can pass through lipid bilayers along its concentration gradient, whereas ammonium is orders of magnitude less permeant. A transmembrane electrical and pH gradient will therefore affect NH4+/NH3, equilibrium. Plants and some microorganisms acidify their external environment and utilize membrane-bound ammonium transport proteins, so internal ammonia concentration may be more than 100 times enriched compared to the external space. Besides pH, membrane potential and transporters, enzymatic reactions that generate or remove ammonium are also important in maintaining its concentration. For example, in microorganisms and plants, ammonium is rapidly and efficiently assimilated by enzymes such as glutamine synthetase and glutamate dehydrogenase. As high levels of ammonium can be cytotoxic, cytoplasmic ammonium has to be kept low. To maintain desired cytoplasmic concentrations and to promote nitrogen assimilation and growth, microorganisms and plants have evolved highly specific uptake and, because of passive leakage of ammonia out of the cells, re-uptake mechanisms. The mechanism of transport for import and export in different species - whether the transporters use amm
A Semiclassical Heat Kernel Proof of the Poincaré-Hopf Theorem
Matthias Ludewig
Mathematics , 2013,
Abstract: We treat the Witten operator on the de Rham complex with semiclassical heat kernel methods to derive the Poincar\'e-Hopf theorem and degenerate generalizations of it. Thereby, we see how the semiclassical asymptotics of the Witten heat kernel are related to approaches using the Thom form of Mathai and Quillen.
Vector Fields with a non-degenerate Source
Matthias Ludewig
Mathematics , 2013, DOI: 10.1016/j.geomphys.2014.01.014
Abstract: We discuss the solution theory of operators of the form $\nabla_X + A$, acting on smooth sections of a vector bundle with connection $\nabla$ over a manifold $M$, where $X$ is a vector field having a critical point with positive linearization at some point $p \in M$. As an operator on a suitable space of smooth sections $\Gamma^\infty(U, \V)$, it fulfills a Fredholm alternative, and the same is true for the adjoint operator. Furthermore, we show that the solutions depend smoothly on the data $\nabla$, $X$ and $A$.
Asymptotic eigenfunctions for Schr?dinger operators on a vector bundle
Matthias Ludewig,Elke Rosenberger
Mathematics , 2013,
Abstract: In the limit $\hbar\to 0$, we analyze a class of Schr\"odinger operators $H_\hbar = \hbar^2 L + \hbar W + V\cdot \mathrm{id}_\Eh$ acting on sections of a vector bundle $\Eh$ over a Riemannian manifold $M$ where $L$ is a Laplace type operator, $W$ is an endomorphism field and the potential energy $V$ has a non-degenerate minimum at some point $p\in M$. We construct quasimodes of WKB-type near $p$ for eigenfunctions associated with the low lying eigenvalues of $H_\hbar$. These are obtained from eigenfunctions of the associated harmonic oscillator $H_{p, \hbar}$ at $p$, acting on $C^\infty (T_pM, \Eh_p)$.
Immunopathological Basis of Virus-induced Myocarditis
Reinhard Maier,Philippe Krebs,Burkhard Ludewig
Clinical and Developmental Immunology , 2004, DOI: 10.1080/10446670410001670427
Abstract: Heart diseases are an important cause of morbidity and mortality in industrialized countries. Dilated cardiomyopathy (DCM), one of the most common heart diseases, may be the consequence of infectionassociated myocardits. Coxsackievirus B3 (CVB3) can be frequently detected in the inflamed heart muscle. CVB3-induced acute myocarditis is most likely the consequence of direct virus-induced myocyte damage, whereas chronic CVB3 infection-associated heart disease is dominated by its immunopathological sequelae. Bona fide autoimmunity, for example, directed against cardiac myosin, may favor chronic destructive immune damage in the heart muscle and thereby promote the development of DCM. The immunopathogenesis of myocarditis and subsequent DCM induced either by pathogens or autoantigens can be investigated in well-established animal models. In this article, we review recent studies on the role of viruses, with particular emphasis on CVB3, and different immunological effector mechanisms in initiation and progression of myocarditis.
Scapular and rotator cuff muscle activity during arm elevation: a review of normal function and alterations with shoulder impingement
Phadke, V;Camargo, PR;Ludewig, PM;
Brazilian Journal of Physical Therapy , 2009, DOI: 10.1590/S1413-35552009005000012
Abstract: objective: the purpose of this manuscript is to review current knowledge of how muscle activation and force production contribute to shoulder kinematics in healthy subjects and persons with shoulder impingement. results: the middle and lower serratus anterior muscles produce scapular upward rotation, posterior tilting, and external rotation. upper trapezius produces clavicular elevation and retraction. the middle trapezius is primarily a medial stabilizer of the scapula. the lower trapezius assists in medial stabilization and upward rotation of the scapula. the pectoralis minor is aligned to resist normal rotations of the scapula during arm elevation. the rotator cuff is critical to stabilization and prevention of excess superior translation of the humeral head, as well as production of glenohumeral external rotation during arm elevation. alterations in activation amplitude or timing have been identified across various investigations of subjects with shoulder impingement as compared to healthy controls. these include decreased activation of the middle or lower serratus anterior and rotator cuff, delayed activation of middle and lower trapezius, and increased activation of the upper trapezius and middle deltoid in impingement subjects. in addition, subjects with a short resting length of the pectoralis minor exhibit altered scapular kinematic patterns similar to those found in persons with shoulder impingement. conclusion: these normal muscle functional capabilities and alterations in patient populations should be considered when planning exercise approaches for the rehabilitation of these patients.
Scapular and rotator cuff muscle activity during arm elevation: a review of normal function and alterations with shoulder impingement Atividade dos músculos escapulares e do manguito rotator durante a eleva o do bra o: uma revis o da fun o normal e das altera es na síndrome do impacto
V Phadke,PR Camargo,PM Ludewig
Brazilian Journal of Physical Therapy , 2009,
Abstract: OBJECTIVE: The purpose of this manuscript is to review current knowledge of how muscle activation and force production contribute to shoulder kinematics in healthy subjects and persons with shoulder impingement. RESULTS: The middle and lower serratus anterior muscles produce scapular upward rotation, posterior tilting, and external rotation. Upper trapezius produces clavicular elevation and retraction. The middle trapezius is primarily a medial stabilizer of the scapula. The lower trapezius assists in medial stabilization and upward rotation of the scapula. The pectoralis minor is aligned to resist normal rotations of the scapula during arm elevation. The rotator cuff is critical to stabilization and prevention of excess superior translation of the humeral head, as well as production of glenohumeral external rotation during arm elevation. Alterations in activation amplitude or timing have been identified across various investigations of subjects with shoulder impingement as compared to healthy controls. These include decreased activation of the middle or lower serratus anterior and rotator cuff, delayed activation of middle and lower trapezius, and increased activation of the upper trapezius and middle deltoid in impingement subjects. In addition, subjects with a short resting length of the pectoralis minor exhibit altered scapular kinematic patterns similar to those found in persons with shoulder impingement. CONCLUSION: These normal muscle functional capabilities and alterations in patient populations should be considered when planning exercise approaches for the rehabilitation of these patients. OBJETIVO: O objetivo deste manuscrito é revisar o conhecimento atual sobre como a ativa o muscular e a produ o de for a contribuem para a cinemática do ombro em indivíduos saudáveis e em pessoas com síndrome do impacto. RESULTADOS: As por es média e inferior do músculo serrátil anterior produzem rota o para cima, inclina o posterior e rota o externa na escápula. O trapézio superior produz eleva o e retra o da clavícula. O trapézio médio é principalmente um estabilizador medial da escápula. O trapézio inferior auxilia na estabiliza o medial e rota o para cima da escápula. O músculo peitoral menor está alinhado para resistir às rota es normais da escápula durante a eleva o do bra o. O manguito rotador é crucial para a estabiliza o e preven o do excesso de transla o superior da cabe a do úmero, assim como para a produ o de rota o externa na glenoumeral durante a eleva o do bra o. Foram identificadas altera es na amplitude ou no tempo de ativa
Page 1 /1936
Display every page Item


Home
Copyright © 2008-2017 Open Access Library. All rights reserved.