954 resultados para Two-component systems PhoBR and PhoPQ
Resumo:
Starch is the main form in which plants store carbohydrates reserves, both in terms of amounts and distribution among different plant species. Carbohydrates are direct products of photosynthetic activity, and it is well know that yield efficiency and production are directly correlated to the amount of carbohydrates synthesized and how these are distributed among vegetative and reproductive organs. Nowadays, in pear trees, due to the modernization of orchards, through the introduction of new rootstocks and the development of new training systems, the understanding and the development of new approaches regarding the distribution and storage of carbohydrates, are required. The objective of this research work was to study the behavior of carbohydrate reserves, mainly starch, in different pear tree organs and tissues: i.e., fruits, leaves, woody organs, roots and flower buds, at different physiological stages during the season. Starch in fruit is accumulated at early stages, and reached a maximum concentration during the middle phase of fruit development; after that, its degradation begins with a rise in soluble carbohydrates. Moreover, relationships between fruit starch degradation and different fruit traits, soluble sugars and organic acids were established. In woody organs and roots, an interconversion between starch and soluble carbohydrates was observed during the dormancy period that confirms its main function in supporting the growth and development of new tissues during the following spring. Factors as training systems, rootstocks, types of bearing wood, and their position on the canopy, influenced the concentrations of starch and soluble carbohydrates at different sampling dates. Also, environmental conditions and cultural practices must be considered to better explain these results. Thus, a deeper understanding of the dynamics of carbohydrates reserves within the plant could provide relevant information to improve several management practices to increase crop yield efficiency.
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Das Enterobakterium Escherichia coli sowie das Bodenbakterium Bacillus subtilis können C4-Dicarbonsäuren als aerobe Kohlenstoffquelle zur Energiekonservierung nutzen. Die Regulation des C4-Dicarboxylatstoffwechsels erfolgt in E. coli und B. subtilis durch das Zweikomponentensystem DcuSREc bzw. DctSRBs, bestehend aus einer Sensorkinase und einem Responseregulator. Diese kontrollieren die Expression des C4-Dicarboxylat-Transporters DctA. Der Sensor DcuSEc benötigt für seine Funktion im aeroben Stoffwechsel den Transporter DctA als Cosensor. Für das DctSRBs-System gibt es Hinweise aus genetischen Untersuchungen, dass DctSBs das Bindeprotein DctBBs und möglicherweise auch DctABs als Cosensoren für seine Funktion benötigt. In dieser Arbeit sollte ein direkter Nachweis geführt werden, ob DctBBs und DctABs gemeinsam oder nur jeweils eine der Komponenten als Cosensoren für DctSBs fungieren. Sowohl für DctBBs als auch für DctABs wurde eine direkte Protein-Protein-Interaktion mit DctSBs durch zwei in vivo Interaktionsmethoden nachgewiesen. Beide Methoden beruhen auf der Co-Reinigung der Interaktionspartner mittels Affinitätschromatographie und werden je nach Affinitätssäule als mSPINE oder mHPINE (Membrane Strep/His-Protein INteraction Experiment) bezeichnet. Die Interaktion von DctSBs mit DctBBs wurde zusätzlich über ein bakterielles Two-Hybrid System nachgewiesen. Nach Coexpression mit DctSBs interagieren DctABs und DctBBs in mSPINE-Tests gleichzeitig mit der Sensorkinase. DctSBs bildet somit eine sensorische DctS/DctA/DctB-Einheit in B. subtilis und das Bindeprotein DctBBs agiert nur als Cosensor, nicht aber als Transport-Bindeprotein. Eine direkte Interaktion zwischen dem Transporter DctABs und dem Bindeprotein DctBBs besteht nicht. Transportmessungen belegen, dass der DctA-vermittelte Transport von [14C]-Succinat unabhängig ist von DctBBs. Außerdem wurde untersucht, ob Zweikomponentensysteme aus anderen Bakteriengruppen nach einem ähnlichen Schema wie DcuSREc bzw. DctSRBs aufgebaut sind. Das thermophile Bakterium Geobacillus kaustophilus verfügt über ein DctSR-System, welches auf genetischer Ebene mit einem Transporter des DctA-Typs und einem DctB-Bindeprotein geclustert vorliegt. Die Sensorkinase DctSGk wurde in E. coli heterolog exprimiert und gereinigt. Diese zeigt in einer E. coli DcuS-Insertionsmutanten Komplementation der DcuS-Funktion und besitzt dabei Spezifität für die C4-Dicarbonsäuren Malat, Fumarat, L-Tartrat und Succinat sowie für die C6-Tricarbonsäure Citrat. In Liposomen rekonstituiertes DctSGk zeigt Autokinase-Aktivität nach Zugabe von [γ-33P]-ATP. Der KD-Wert für [γ-33P]-ATP der Kinasedomäne von DctSGk liegt bei 43 μM, die Affinität für ATP ist damit etwa 10-fach höher als in DcuSEc.
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In questo lavoro di tesi è stato svolto uno studio analitico sul modello di Hubbard esteso unidimensionale al fine di osservare la presenza di eventuali risonanze che possano dare origine alla formazione di stati legati di due particelle. L'esistenza di uno stato legato stabile ha suscitato grande interesse negli ultimi anni, sia in ambito teorico che sperimentale, poichè è alla base di molti fenomeni che vengono osservati nei sistemi a molti corpi a basse temperature, come il BCS-BEC crossover. Pertanto si è ritenuto utile studiare il problema a due corpi nel modello di Hubbard esteso, che in generale non è integrabile. Il modello considerato contiene interazioni a primi e secondi vicini, in aggiunta all'interazione di contatto presente nel modello di Hubbard. Il problema è stato indagato analiticamente attraverso il Bethe ansatz, che consente di trovare tutti gli autovalori e le autofunzioni dell'Hamiltoniana. L'ansatz di Bethe sulla funzione d'onda è stato generalizzato per poter tener conto dei termini di interazione a più lungo raggio rispetto all'interazione di contatto. Si trova che, in questo modello, nel limite termodinamico, possono avvenire delle risonanze (o quasi-risonanze) in cui la lunghezza di scattering diverge, contrariamente a quanto avviene nel modello di Hubbard. Tale fenomeno si verifica quando il livello energetico discreto degli stati legati “tocca” la banda di scattering. Inoltre, con l'aggiunta di nuovi termini di interazione emergono nuovi stati legati. Nel caso in esame, si osservano due famiglie di stati legati, se lo spin totale delle due particelle è 1, e tre famiglie di stati legati, se lo spin totale è 0.
Resumo:
This paper describes informatics for cross-sample analysis with comprehensive two-dimensional gas chromatography (GCxGC) and high-resolution mass spectrometry (HRMS). GCxGC-HRMS analysis produces large data sets that are rich with information, but highly complex. The size of the data and volume of information requires automated processing for comprehensive cross-sample analysis, but the complexity poses a challenge for developing robust methods. The approach developed here analyzes GCxGC-HRMS data from multiple samples to extract a feature template that comprehensively captures the pattern of peaks detected in the retention-times plane. Then, for each sample chromatogram, the template is geometrically transformed to align with the detected peak pattern and generate a set of feature measurements for cross-sample analyses such as sample classification and biomarker discovery. The approach avoids the intractable problem of comprehensive peak matching by using a few reliable peaks for alignment and peak-based retention-plane windows to define comprehensive features that can be reliably matched for cross-sample analysis. The informatics are demonstrated with a set of 18 samples from breast-cancer tumors, each from different individuals, six each for Grades 1-3. The features allow classification that matches grading by a cancer pathologist with 78% success in leave-one-out cross-validation experiments. The HRMS signatures of the features of interest can be examined for determining elemental compositions and identifying compounds.
Resumo:
Non-perforating abomasal lesions are a considerable problem affecting more than half the population of veal calves. The objective of the present study was to assess the prevalence of pyloric and fundic abomasal lesions in Swiss veal calves at slaughter and to compare the occurrence of non-perforating abomasal lesions between two different production programs ('Naturafarm' and 'conventional'). 'Conventional'-production settings met the minimal standards as defined by the Swiss animal welfare legislation, whereas 'Naturafarm' production complied with increased animal welfare requirements. In order to identify risk factors for the development of abomasal lesions, information on management, housing, and feeding was obtained by a questionnaire. A total of 125 abomasa were randomly selected in one large abattoir. They were examined macroscopically, and the occurence of lesions in either the fundic or pyloric region of the abomasum was recorded separately. Animals raised in the 'conventional'-production setting revealed a significantly higher prevalence of lesions in the fundic part. Factors significantly affecting the prevalence of non-perforating lesions in the fundic part were the 'conventional'-production environment, including missing access to an outside pen, missing access to water and straw as the only roughage, feeding by bucket and the liquid milk by-product Protofit in combination with the powder Sprayfit.
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We propose an innovative, integrated, cost-effective health system to combat major non-communicable diseases (NCDs), including cardiovascular, chronic respiratory, metabolic, rheumatologic and neurologic disorders and cancers, which together are the predominant health problem of the 21st century. This proposed holistic strategy involves comprehensive patient-centered integrated care and multi-scale, multi-modal and multi-level systems approaches to tackle NCDs as a common group of diseases. Rather than studying each disease individually, it will take into account their intertwined gene-environment, socio-economic interactions and co-morbidities that lead to individual-specific complex phenotypes. It will implement a road map for predictive, preventive, personalized and participatory (P4) medicine based on a robust and extensive knowledge management infrastructure that contains individual patient information. It will be supported by strategic partnerships involving all stakeholders, including general practitioners associated with patient-centered care. This systems medicine strategy, which will take a holistic approach to disease, is designed to allow the results to be used globally, taking into account the needs and specificities of local economies and health systems.
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Long-term dietary intervention frequently induces a rapid weight decline followed by weight stabilization/regain. Here, we sought to identify adipokine biomarkers that may reflect continued beneficial effects of dieting despite partial weight regain.
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There is increasing recognition that transdisciplinary approaches are needed to create suitable knowledge for sustainable water management. However, there is no common understanding of what transdisciplinary research may be and there is very limited debate on potentials and challenges regarding its implementation. Against this background, this paper presents a conceptual framework for transdisciplinary co-production of knowledge in water management projects oriented towards more sustainable use of water. Moreover, first experiences with its implementation are discussed. In so doing, the focus lies on potentials and challenges related to the co-production of systems, target and transformation knowledge by researchers and local stakeholders.
Resumo:
For understanding the major- and minor-groove hydration patterns of DNAs and RNAs, it is important to understand the local solvation of individual nucleobases at the molecular level. We have investigated the 2-aminopurine center dot H2O. monohydrate by two-color resonant two-photon ionization and UV/UV hole-burning spectroscopies, which reveal two isomers, denoted A and B. The electronic spectral shift delta nu of the S-1 <- S-0 transition relative to bare 9H-2-aminopurine (9H-2AP) is small for isomer A (-70 cm(-1)), while that of isomer B is much larger (delta nu = 889 cm(-1)). B3LYP geometry optimizations with the TZVP basis set predict four cluster isomers, of which three are doubly H-bonded, with H2O acting as an acceptor to a N-H or -NH2 group and as a donor to either of the pyrimidine N sites. The "sugar-edge" isomer A is calculated to be the most stable form with binding energy D-e = 56.4 kJ/mol. Isomers B and C are H-bonded between the -NH2 group and pyrimidine moieties and are 2.5 and 6.9 kJ/mol less stable, respectively. Time-dependent (TD) B3LYP/TZVP calculations predict the adiabatic energies of the lowest (1)pi pi* states of A and B in excellent agreement with the observed 0(0)(0) bands; also, the relative intensities of the A and B origin bands agree well with the calculated S-0 state relative energies. This allows unequivocal identification of the isomers. The R2PI spectra of 9H-2AP and of isomer A exhibit intense low-frequency out-of-plane overtone and combination bands, which is interpreted as a coupling of the optically excited (1)pi pi* state to the lower-lying (1)n pi* dark state. In contrast, these overtone and combination bands are much weaker for isomer B, implying that the (1)pi pi* state of B is planar and decoupled from the (1)n pi* state. These observations agree with the calculations, which predict the (1)n pi* above the (1)pi pi* state for isomer B but below the (1)pi pi* for both 9H-2AP and isomer A.
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Two healthy cats underwent elective surgical procedures under general anesthesia. One developed severe esophagitis leading to esophageal rupture, mediastinitis, and pyothorax. The other cat developed esophageal stricture, diverticulum formation, and suspected iatrogenic perforation. Both cats had signs of dysphagia and regurgitation beginning a few days after anesthesia. The first cat also had severe dyspnea due to septic pleural effusion and pneumomediastinum. In the second cat, endoscopy revealed diffuse esophagitis, an esophageal stricture, and a large esophageal diverticulum. Rupture of the esophageal wall occurred while inflating the esophagus for inspection. Due to the poor prognosis, both cats were euthanized. Necropsy revealed severe esophageal changes. Postanesthetic esophagitis has been previously described in dogs and cats; however, severe life-threatening esophageal injuries rarely occur as a sequel to general anesthesia. To the authors' knowledge, esophageal rupture secondary to perianesthetic reflux has never been reported in cats.
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We study how species richness of arthropods relates to theories concerning net primary productivity, ambient energy, water-energy dynamics and spatial environmental heterogeneity. We use two datasets of arthropod richness with similar spatial extents (Scandinavia to Mediterranean), but contrasting spatial grain (local habitat and country). Samples of ground-dwelling spiders, beetles, bugs and ants were collected from 32 paired habitats at 16 locations across Europe. Species richness of these taxonomic groups was also determined for 25 European countries based on the Fauna Europaea database. We tested effects of net primary productivity (NPP), annual mean temperature (T), annual rainfall (R) and potential evapotranspiration of the coldest month (PETmin) on species richness and turnover. Spatial environmental heterogeneity within countries was considered by including the ranges of NPP, T, R and PETmin. At the local habitat grain, relationships between species richness and environmental variables differed strongly between taxa and trophic groups. However, species turnover across locations was strongly correlated with differences in T. At the country grain, species richness was significantly correlated with environmental variables from all four theories. In particular, species richness within countries increased strongly with spatial heterogeneity in T. The importance of spatial heterogeneity in T for both species turnover across locations and for species richness within countries suggests that the temperature niche is an important determinant of arthropod diversity. We suggest that, unless climatic heterogeneity is constant across sampling units, coarse-grained studies should always account for environmental heterogeneity as a predictor of arthropod species richness, just as studies with variable area of sampling units routinely consider area.
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In excisional body-contouring surgery the surgeon is often confronted with time-consuming closure of long wounds. Recently, a new combination of a self-adhering mesh together with a liquid 2-octyl cyanoacrylate adhesive (Prineo™; Ethicon, Inc., Somerville, NJ, USA) has been introduced to replace intracutaneous running suture.
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Sonography is an important diagnostic tool to examine the gastrointestinal tract of dogs with chronic diarrhea. Two-dimensional grayscale ultrasound parameters to assess for various enteropathies primarily focus on wall thickness and layering. Mild, generalized thickening of the intestinal wall with maintenance of the wall layering is common in inflammatory bowel disease. Quantitative and semi-quantitative spectral Doppler arterial waveform analysis can be utilized for various enteropathies, including inflammatory bowel disease and food allergies. Dogs with inflammatory bowel disease have inadequate hemodynamic responses during digestion of food. Dogs with food allergies have prolonged vasodilation and lower resistive and pulsatility indices after eating allergen-inducing foods.