Optimierung und Etablierung von Testmethoden und funktionelle Untersuchung verschiedener Aquaporine & Aquaglyceroporine

Die vorliegende Arbeit behandelte drei Themen: 1) Klärung der umstrittenen Wasserleitfähigkeit von PfAQP, 2) Ammoniakleitfähigkeit von Aquaglyceroporinen am Beispiel von hAQP8 und PfAQP und 3) H2O2-Permeabilität von Aquaporinen und Aquaglyceroporinen. Durch den Einsatz verschiedener Polyole (Saccharose, Sorbitol, PEG300 und Glycerol) konnte die Wasserleitfähigkeit von PfAQP und EcGlpF geklärt werden. EcGlpF, wie viele Aquaglyceroporine, kann Glycerol aber praktisch kein Wasser transportieren. Die Wasserleitfähigkeit von PfAQP ist von dem eingesetzten Polyol abhängig. In der großen cyclischen Saccharose kann PfAQP sowohl Wasser als auch Glycerol gut leiten. Dagegen hemmt Sorbitol den Wassertransport (IC50 = 0,81 M) und erniedrigt die Glycerolpermeabilität um 80 %. Der Hemmeffekt von Sorbitol beruht nicht auf das Eindringen und Verschließen des Kanals sondern auf die Interaktion mit dem Einmündungsbereich. Glycerol wird durch PfAQP besser transportiert als Harnstoff, auch wenn beide Solute in unterschiedlichen Verhältnissen gemischt sind. Somit trifft die Molenbruch-Anomalie für die Aquaporine unter den herrschenden Testbedingungen nicht zu. Es konnte experimentell ein Protokoll zur Beladung von Hefezellen mit dem pH-sensitiven Fluoresceindiacetat (FDA) etabliert werden, mit dessen Hilfe die Ammoniakleitfähigkeit von Aquaporinen und Aquaglyceroporinen gemessen werden kann. Damit wurde die Ammoniakpermeabilität von hAQP8 und PfAQP gemessen. Beide Aquaporine erhöhten die Ammoniakpermeabilität um das drei- bzw. zweifache gegenüber den Kontrollzellen. Im letzten Teil wurde die H2O2-Leitfähigkeit beider AQP-Subfamilien gegenübergestellt. Die schnell wasserleitenden Isoformen (hAQP1, rAQP1 und hAQP8) sind in der Lage H2O2 schneller zu transportieren als die glycerolleitenden hAP9 und PfAQP. Die Mutante rAQP1 H180A besitzt eine 4mal größere ar/R-Region als der Wildtyp. Um den gleichen Faktor erhöhte sich die H2O2-Leitfähigkeit dieser Mutante. Im Gegensatz dazu verringerte sich die H2O2-Leitfähigkeit von Mutanten, in denen die ar/R-Region verkleinert wurde wie z. B. hAQP8 I200H und rAQP1 H180F

Soil erosion and sediment transport modelling using hydrological models and remote sensing techniques in Wadi Billi, Egypt

Modelling soil erosion and sediment transport are vital to assess the impact of the flash floods. However, limited research works have studied sediment transport, especially in Egypt. This paper employs the HEC-HMS lumped hydrological model to predict the sediment load due to the flood event of 9th March 2014 in Wadi Billi, Egypt. The Modified USLE model has been used to calculate the total upland erosion, while Laursen-Copeland has been used to simulate load streams’ sediment transport potential. The Normalized Difference Vegetation Index (NDVI) has been applied over Landsat 8 image captured on 20th February 2014 using ArcMap 10.5 to determine the vegetation cover based on its spectral footprint. The resulted sedigraph showed accumulation of more than five thousand tons of sediments at the Wadi’s outlet. The results are crucial to design a suitable stormwater management system to protect the downstream urban area and to use flood water for groundwater recharge.TU Berlin, Open-Access-Mittel – 202

Altered respiratory microbiota composition and functionality associated with asthma early in life

BACKGROUND: The microbiota of the respiratory tract has an important role in maintaining respiratory health. However, little is known on the respiratory microbiota in asthmatic patients among Middle Eastern populations. This study investigated the respiratory microbiota composition and functionality associated with asthma in Emirati subjects. METHODS: We performed 16S rRNA and ITS2-gene based microbial profiling of 40 expectorated sputum samples from adult and pediatric Emirati individuals averaging 52 and 7 years of age, respectively with or without asthma. RESULTS: We report bacterial difference belonging to Bacteroidetes, Firmicutes, Fusobacteria and Proteobacteria phyla between asthmatic and non-asthmatic controls. Similarly, fungal difference belonging to Ascomycota, Basidiomycota phyla and other unclassified fungi. Differential abundance testing among asthmatic individuals with relation to Asthma Control Test show a significant depletion of Penicillium aethiopicum and Alternaria spp., among poorly controlled asthmatics. Moreover, data suggest a significant expansion of Malassezia spp. and other unclassified fungi in the airways of those receiving steroids and leukotriene receptor antagonists’ combination therapy, in contrast to those receiving steroids alone. Functional profiling from 16S data showed marked differences between pediatric asthmatic and non-asthmatic controls, with pediatric asthmatic patients showing an increase in amino acid (p-value < 5.03 × 10− 7), carbohydrate (p-value < 4.76 × 10− 7), and fatty acid degradation (p-value < 6.65 × 10− 7) pathways, whereas non-asthmatic controls are associated with increase in amino acid (p-value < 8.34 × 10− 7), carbohydrate (p-value < 3.65 × 10− 7), and fatty acid (p-value < 2.18 × 10− 6) biosynthesis pathways in concordance with enterotype composition. CONCLUSIONS: These differences provide an insight into respiratory microbiota composition in Emirati population and its possible role in the development of asthma early in life. This study provides important information that may eventually lead to the development of screening biomarkers to predict early asthma development and novel therapeutic approaches

Transit of H2O2 across the endoplasmic reticulum membrane is not sluggish

Cellular metabolism provides various sources of hydrogen peroxide (H2O2) in different organelles and compartments. The suitability of H2O2 as an intracellular signaling molecule therefore also depends on its ability to pass cellular membranes. The propensity of the membranous boundary of the endoplasmic reticulum (ER) to let pass H2O2 has been discussed controversially. In this essay, we challenge the recent proposal that the ER membrane constitutes a simple barrier for H2O2 diffusion and support earlier data showing that (i) ample H2O2 permeability of the ER membrane is a prerequisite for signal transduction, (ii) aquaporin channels are crucially involved in the facilitation of H2O2 permeation, and (iii) a proper experimental framework not prone to artifacts is necessary to further unravel the role of H2O2 permeation in signal transduction and organelle biology. © 2016 Elsevier Inc

Beyond water homeostasis:diverse functional roles of mammalian aquaporins

Background - Aquaporin (AQP) water channels are best known as passive transporters of water that are vital for water homeostasis. Scope of review - AQP knockout studies in whole animals and cultured cells, along with naturally occurring human mutations suggest that the transport of neutral solutes through AQPs has important physiological roles. Emerging biophysical evidence suggests that AQPs may also facilitate gas (CO2) and cation transport. AQPs may be involved in cell signalling for volume regulation and controlling the subcellular localization of other proteins by forming macromolecular complexes. This review examines the evidence for these diverse functions of AQPs as well their physiological relevance. Major conclusions - As well as being crucial for water homeostasis, AQPs are involved in physiologically important transport of molecules other than water, regulation of surface expression of other membrane proteins, cell adhesion, and signalling in cell volume regulation. General significance - Elucidating the full range of functional roles of AQPs beyond the passive conduction of water will improve our understanding of mammalian physiology in health and disease. The functional variety of AQPs makes them an exciting drug target and could provide routes to a range of novel therapies

ROS-dependent signaling pathways in plants and algae exposed to high light: Comparisons with other eukaryotes

Abstract Like all aerobic organisms, plants and algae co-opt reactive oxygen species (ROS) as signaling molecules to drive cellular responses to changes in their environment. In this respect, there is considerable commonality between all eukaryotes imposed by the constraints of ROS chemistry, similar metabolism in many subcellular compartments, the requirement for a high degree of signal specificity and the deployment of thiol peroxidases as transducers of oxidizing equivalents to regulatory proteins. Nevertheless, plants and algae carry out specialised signaling arising from oxygenic photosynthesis in chloroplasts and photoautotropism, which often induce an imbalance between absorption of light energy and the capacity to use it productively. A key means of responding to this imbalance is through communication of chloroplasts with the nucleus to adjust cellular metabolism. Two ROS, singlet oxygen (1O2) and hydrogen peroxide (H2O2), initiate distinct signaling pathways when photosynthesis is perturbed. 1O2, because of its potent reactivity means that it initiates but does not transduce signaling. In contrast, the lower reactivity of H2O2 means that it can also be a mobile messenger in a spatially-defined signaling pathway. How plants translate a H2O2 message to bring about changes in gene expression is unknown and therefore, we draw on information from other eukaryotes to propose a working hypothesis. The role of these ROS generated in other subcellular compartments of plant cells in response to HL is critically considered alongside other eukaryotes. Finally, the responses of animal cells to oxidative stress upon high irradiance exposure is considered for new comparisons between plant and animal cells

Transcending boundaries : modern poetic responses to the city

This thesis examines poetic representations of the city in the works of T.S. Eliot, William Carlos Williams, Roy Fisher, Iain Sinclair, and Aidan Andrew Dun. Chapter One discusses Eliot's vision of the city, arguing that Eliot was always seeking new ways for forming urban imagery. Concentrating on the relation between poetic form and urban images, I look at Eliot's poetry including his unpublished poems to highlight how modernism, form, and the city inform one another. Chapter Two examines briefly Williams's response to Eliot's vision of London in The Waste Land, highlighting the contrast between Eliot's cosmopolitanism and Williams's localism/ provincialism. Exploring the relation between Williams's representation of Paterson in Pater son and Roy Fisher's poetic representation of Birmingham in City and A Furnace, I reveal that Fisher adopts Williams's approach to the city but subsequently diverges from it thus creating a new urban poetics. Chapter Three investigates Iain Sinclair's visionary representation of London in Lud Heat in conjunction with Lights Out for the Territory, and I examine Sinclair's notion of the city as a text. I argue that Sinclair's textual representation of London gives a new meaning to the relation between poetry and the city. I also look at Sinclair's rewriting of the flaneur as a strategy to elide the boundaries between real and imagined spaces. Chapter Four concentrates on Aidan Andrew Dun's representation of London in his long poem Vale Royal, and I look at Dun's use of the two romantic poets (William Blake and Thomas Chatterton) as a strategy to revive the city's metropolitan history. I compare Dun's vision of London with that of Sinclair and Eliot, stressing how Dun engages in rewriting modernism's definitive view of the city

Soil erosion and sediment transport modelling using hydrological models and remote sensing techniques in Wadi Billi, Egypt

Modelling soil erosion and sediment transport are vital to assess the impact of the flash floods. However, limited research works have studied sediment transport, especially in Egypt. This paper employs the HEC-HMS lumped hydrological model to predict the sediment load due to the flood event of 9th March 2014 in Wadi Billi, Egypt. The Modified USLE model has been used to calculate the total upland erosion, while Laursen-Copeland has been used to simulate load streams' sediment transport potential. The Normalized Difference Vegetation Index (NDVI) has been applied over Landsat 8 image captured on 20th February 2014 using ArcMap 10.5 to determine the vegetation cover based on its spectral footprint. The resulted sedigraph showed accumulation of more than five thousand tons of sediments at the Wadi's outlet. The results are crucial to design a suitable stormwater management system to protect the downstream urban area and to use flood water for groundwater recharge

Soil erosion and sediment transport modelling using hydrological models and remote sensing techniques in Wadi Billi, Egypt

Modelling soil erosion and sediment transport are vital to assess the impact of the flash floods. However, limited research works have studied sediment transport, especially in Egypt. This paper employs the HEC-HMS lumped hydrological model to predict the sediment load due to the flood event of 9th March 2014 in Wadi Billi, Egypt. The Modified USLE model has been used to calculate the total upland erosion, while Laursen-Copeland has been used to simulate load streams’ sediment transport potential. The Normalized Difference Vegetation Index (NDVI) has been applied over Landsat 8 image captured on 20th February 2014 using ArcMap 10.5 to determine the vegetation cover based on its spectral footprint. The resulted sedigraph showed accumulation of more than five thousand tons of sediments at the Wadi’s outlet. The results are crucial to design a suitable stormwater management system to protect the downstream urban area and to use flood water for groundwater recharge.Technische Universität Berlin (3136)https://www.hec.usace.army.mil/software/hec-hms