TY - THES A1 - Firkala, Tamás T1 - Investigation of nanoparticle-molecule interactions and pharmaceutical model formulations by means of surface enhanced raman spectroscopy Y1 - 2017 ER - TY - GEN A1 - Zehbe, Kerstin A1 - Kollosche, Matthias A1 - Lardong, Sebastian A1 - Kelling, Alexandra A1 - Schilde, Uwe A1 - Taubert, Andreas T1 - Ionogels based on poly(methyl methacrylate) and metal-containing ionic liquids BT - correlation between structure and mechanical and electrical properties N2 - Ionogels (IGs) based on poly(methyl methacrylate) (PMMA) and the metal-containing ionic liquids (ILs) bis-1-butyl-3-methlimidazolium tetrachloridocuprate(II), tetrachloride cobaltate(II), and tetrachlorido manganate(II) have been synthesized and their mechanical and electrical properties have been correlated with their microstructure. Unlike many previous examples, the current IGs show a decreasing stability in stress-strain experiments on increasing IL fractions. The conductivities of the current IGs are lower than those observed in similar examples in the literature. Both effects are caused by a two-phase structure with micrometer-sized IL-rich domains homogeneously dispersed an IL-deficient continuous PMMA phase. This study demonstrates that the IL-polymer miscibility and the morphology of the IGs are key parameters to control the (macroscopic) properties of IGs. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 361 KW - microstructure KW - ionogels KW - ionic liquids KW - phase separation KW - mechanical properties KW - ionic conductivity Y1 - 2017 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-400607 ER - TY - JOUR A1 - Deyou, Tsegaye A1 - Marco, Makungu A1 - Heydenreich, Matthias A1 - Pan, Fangfang A1 - Gruhonjic, Amra A1 - Fitzpatrick, Paul A. A1 - Koch, Andreas A1 - Derese, Solomon A1 - Pelletier, Jerry A1 - Rissanen, Kari A1 - Yenesew, Abiy A1 - Erdelyi, Mate T1 - Isoflavones and Rotenoids from the Leaves of Millettia oblata ssp teitensis JF - Journal of natural products N2 - A new isoflavone, 8-prenylmilldrone (1), and four new rotenoids, oblarotenoids A-D (2-5), along with nine known compounds (6-14), were isolated from the CH2Cl2/CH3OH (1:1) extract of the leaves of Millettia oblata ssp. teitensis by chromatographic separation. The purified compounds were identified by NMR spectroscopic and mass spectrometric analyses, whereas the absolute configurations of the rotenoids were established on the basis of chiroptical data and in some cases by single-crystal X-ray crystallography. Maximaisoflavone J (11) and oblarotenoid C (4) showed weak activity against the human breast cancer cell line MDA-MB-231 with IC50 values of 33.3 and 93.8 mu M, respectively. Y1 - 2017 U6 - https://doi.org/10.1021/acs.jnatprod.7b00255 SN - 0163-3864 SN - 1520-6025 VL - 80 SP - 2060 EP - 2066 PB - American Chemical Society CY - Washington ER - TY - JOUR A1 - Schulze, Nicole A1 - Koetz, Joachim T1 - Kinetically controlled growth of gold nanotriangles in a vesicular template phase by adding a strongly alternating polyampholyte JF - Journal of dispersion science and technology N2 - This paper is focused on the temperature-dependent synthesis of gold nanotriangles in a vesicular template phase, containing phosphatidylcholine and AOT, by adding the strongly alternating polyampholyte PalPhBisCarb. UV-vis absorption spectra in combination with TEM micrographs show that flat gold nanoplatelets are formed predominantly in the presence of the polyampholyte at 45°C. The formation of triangular and hexagonal nanoplatelets can be directly influenced by the kinetic approach, i.e., by varying the polyampholyte dosage rate at 45°C. Corresponding zeta potential measurements indicate that a temperature-dependent adsorption of the polyampholyte on the {111} faces will induce the symmetry breaking effect, which is responsible for the kinetically controlled hindered vertical and preferred lateral growth of the nanoplatelets. KW - Kinetically controlled nanocrystal growth KW - nanotriangles KW - polyampholytes Y1 - 2016 U6 - https://doi.org/10.1080/01932691.2016.1220318 SN - 0193-2691 SN - 1532-2351 VL - 38 IS - 8 SP - 1073 EP - 1078 PB - Taylor & Francis CY - Philadelphia ER - TY - JOUR A1 - Onal, Emel A1 - Sass, Stephan A1 - Hurpin, Jeanne A1 - Ertekin, Kadriye A1 - Topal, Sevinc Zehra A1 - Kumke, Michael Uwe A1 - Hirel, Catherine T1 - Lifetime-Based Oxygen Sensing Properties of palladium(II) and platinum(II) meso-tetrakis(4-phenylethynyl)phenylporphyrin JF - Journal of fluorescence N2 - High oxygen permeable [poly(TMSP)] nanofibers incorporating porphyrin macrocycle as luminescence indicators were prepared by electrospinning technique. The porphyrins involves were modified by i) introducing phenylacetylide substituents on the para position of the phenyl moieties and ii) varying the metal centers [Pt(II) or Pd(II)] of the meso-tetrakisphenylporphyrins. A set of nanofibers; (Pt-TPP)NF, (Pd-TPP)NF, (Pt-TPA)NF and (Pd-TPA)NF were obtained to study their structure-activity relationship toward oxygen. The lifetime-based technique was privileged to take advantage of their long-lived phosphorescent properties. A two-fold enhancement was observed for (Pt-TPA)NF and (Pd-TPA)NF compared to (Pt-TPP)NF and (Pd-TPP)NF demonstrating the positive effect of the phenylacetylide moieties on the lifetime. Also, Silver nanoparticles were included in nanofibers to investigate their influence on lifetime-based oxygen sensitivity, showing that the presence of AgNPs only affects (Pd-TPA)NF. KW - Oxygen sensing KW - Phosphorescence lifetime KW - meso-tetrakisphenylporphyrins KW - Phenylacetylide KW - Nanofibers KW - Poly(trimethylsilylpropyne) matrix Y1 - 2017 U6 - https://doi.org/10.1007/s10895-016-2022-x SN - 1053-0509 SN - 1573-4994 VL - 27 SP - 861 EP - 868 PB - Springer CY - New York ER - TY - THES A1 - Graglia, Micaela T1 - Lignin valorization T1 - Lignin Valorisierung BT - extraction, characterization and applications BT - Extraktion, Charakterisierung und Anwendungen N2 - The topic of this project is the use of lignin as alternative source of aromatic building blocks and oligomers to fossil feedstocks. Lignin is known as the most abundant aromatic polymer in nature and is isolated from the lignocellulosic component of plants by different possible extraction treatments. Both the biomass source and the extraction method affect the structure of the isolated lignin, therefore influencing its further application. Lignin was extracted from beech wood by two different hydrothermal alkaline treatments, which use NaOH and Ba(OH)2 as base and by an acid-catalyzed organosolv process. Moreover, lignin was isolated from bamboo, beech wood and coconut by soda treatment of the biomasses. A comparison of the structural features of such isolated lignins was performed through the use of a wide range of analytical methods. Alkaline lignins resulted in a better candidate as carbon precursor and macromonomers for the synthesis of polymer than organosolv lignin. In fact, alkaline lignins showed higher residual mass after carbonization and higher content of the reactive hydroxy functionalities. In contrast, the lignin source turned out to slightly affect the lignin hydroxyl content. One of the most common lignin modifications is its deconstruction to obtain aromatic molecules, which can be used as starting materials for the synthesis of fine chemicals. Lignin deconstruction leads to a complex mixture of aromatic molecules. A gas chromatographic analytical method was developed to characterize the mixture of products obtained by lignin deconstruction via heterogeneous catalytic hydrogenolysis. The analytical protocol allowed the quantification of three main groups of molecules by means of calibration curves, internal standard and a preliminary silylation step of the sample. The analytical method was used to study the influence of the hydrogenolysis catalyst, temperature and system (flow and batch reactor) on the yield and selectivity of the aromatic compounds. Lignin extracted from beech wood by a hydrothermal process using Ba(OH)2 as base, was functionalized by aromatic nitration in order to add nitrogen functionalities. The final goal was the synthesis of a nitrogen doped carbon. Nitrated lignin was reduced to the amino form in order to compare the influence of different nitrogen functionalities on the porosity of the final carbon. The carbons were obtained by ionothermal treatment of the precursors in the presence of the eutectic salt mixture KCl/ZnCl2 Such synthesized carbons showed micro-, macro- and mesoporosity and were tested for their electrocatalytic activity towards the oxygen reduction reaction. Mesoporous carbon derived from nitro lignin displayed the highest electrocatalytic activity. Lignins isolated from coconut, beech wood and bamboo were used as macromonomers for the synthesis of biobased polyesters. A condensation reaction was performed between lignin and a hyper branched poly(ester-amine), previously obtained by condensation of triethanolamine and adipic acid. The influence of the lignin source and content on the thermochemical and mechanical properties of the final material was investigated. The prepolymer showed adhesive properties towards aluminum and its shear strength was therefore measured. The gluing properties of such synthesized glues turned out to be independent from the lignin source but affected by the amount of lignin in the final material. This work shows that, although still at a laboratory scale, the valorization of lignin can overcome the critical issues of lignin´s structure variability and complexity. N2 - Das Thema dieser Arbeit ist Lignin als alternative Quelle für aromatische Moleküle einzusetzen, welche sonst aus fossilen Rohstoffen hergestellt werden. Lignin ist das am häufigsten vorkommende aromatische Polymer in der Natur. Es wird durch verschiedene Extraktionsmethoden aus pflanzlicher Lignocellulose isoliert. Sowohl der Rohstoff als auch das Extraktionsverfahren beeinflussen die Struktur des isolierten Lignins und bestimmen dadurch die weiteren Anwendungsmöglichkeiten. In der vorliegenden Arbeit die wurde Lignin durch zwei alkalisch hydrothermale Extraktionsmethoden aus Buchenholz extrahiert, wobei entweder NaOH oder Ba(OH)2 verwendet wurde. Eine dritte Methode bedient sich der sogenannten säuerekatalysierten Organosolv-Extraktion. Das Weiteren wurden drei Lignine durch eine Soda Extraktionsmethode aus Bambus, Buchenholz und Kokosnussschalen isoliert. Die Strukturen dieser wurden mit Hilfe verschiedener analytischer Techniken analysiert und verglichen. Während alkalische Lignine sich besser als Ausgangsstoff für poröse Kohlenstoffmaterialien und Makromonomere für die Synthese von Polymeren eignen, zeigen Lignine aus dem Organosolv Prozess weniger gute Eigenschaften hinsichtlich dieser Applikationen. Die bis heute häufigste Modifikation von Lignin beschäftigt sich mit der Aufschließung zu aromatischen Molekülen, welche die Grundlage für die weitere Herstellung von Chemikalien darstellen. Um die Aufschlussprodukte der Hydrogenolyse aus Lignin vergleichen zu können, wurde während dieser Arbeit wurde eine Gaschromatographiemethode entwickelt. In einem weiteren Schritt wurde isoliertes Lignin aus Buchenholzspänen durch Nitrierung mit zusätzlichem Stickstoff funktionalisiert. Das modifizierte Lignin konnte direkt al Präkursor für stickstoffdotierte kohlen dienen, welche mittels ionothermaler Synthese mit Hilfe von KCl/ZnCl2 als eutektischem Salz hergestellt wurden. Diese Materialien wurden erfolgreich in der Sauerstoffreduktion als Katalysator zum Einsatz gebracht. Die gewonnen Lignine aus Kokosnussschalen, Bambus und Buchenholz wurden als Makromonomere für die Herstellung von biobasiertem Polyester verwendet. Sowohl die thermochemischen als auch die mechanischen Eigenschaften wurden durch die unterschiedlichen Lignine der verschiedenen Pflanzen beeinflusst. Das hergestellte Polymer zeigte gute Eigenschaften als Biomass-basierter Kleber. Mit dieser Arbeit konnte gezeigt werden, dass Lignin, obwohl es eine sehr variable und komplexe Struktur aufweis, in verschiedenen Anwendungsbereichen zum Einsatz kommen kann, auch wenn diese bis heute nur im Labormaßstab verwirklicht wurden. KW - Lignin KW - biorefinery KW - biomass KW - Lignin KW - Biomasse KW - Bioraffinerie Y1 - 2017 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-104863 ER - TY - JOUR A1 - Hu, Shuangyan A1 - Zhao, Junpeng A1 - Zhang, Guangzhao A1 - Schlaad, Helmut T1 - Macromolecular architectures through organocatalysis JF - Progress in Polymer Science N2 - In virtue of the rising demand for metal-free polymeric materials, organocatalytic polymerization has emerged and blossomed unprecedentedly in the past 15 years into an appealing research area and a powerful arsenal for polymer synthesis. In addition to the inherent merits as being metal-free, small molecule organocatalysts have also provided opportunities to develop alternative and, in many cases, more expedient synthetic approaches toward macromolecular architectures, that play a crucial role in shaping the properties of the obtained polymers. A majority of preliminary studies exploring for new catalysts, catalytic mechanisms and optimized polymerization conditions are extended to application of the catalytic systems on rational design and controlled synthesis of various macromolecular architectures. Such endeavors are described in this review, categorized by the architectural elements including chain structure (types, sequence and composition of monomeric units constituting the polymer chains), topological structure (the fashion different polymer chains are covalently attached to each other within the macromolecule) and functionality (position and amount of functional groups that endow the entire macromolecule with specific chemical, physico-chemical or biological properties). (C) 2017 Published by Elsevier B.V. KW - Organocatalytic polymerization KW - Metal-free polymerization KW - Macromolecular architecture KW - Controlled polymer synthesis Y1 - 2017 U6 - https://doi.org/10.1016/j.progpolymsci.2017.07.002 SN - 0079-6700 SN - 1873-1619 VL - 74 SP - 34 EP - 77 PB - Elsevier CY - Oxford ER - TY - JOUR A1 - Ghaisari, Sara A1 - Winklhofer, Michael A1 - Strauch, Peter A1 - Klumpp, Stefan A1 - Faivre, Damien T1 - Magnetosome Organization in Magnetotactic Bacteria Unraveled by Ferromagnetic Resonance Spectroscopy JF - Biophysical journal N2 - Magnetotactic bacteria form assemblies of magnetic nanoparticles called magnetosomes. These magnetosomes are typically arranged in chains, but other forms of assemblies such as clusters can be observed in some species and genetic mutants. As such, the bacteria have developed as a model for the understanding of how organization of particles can influence the magnetic properties. Here, we use ferromagnetic resonance spectroscopy to measure the magnetic anisotropies in different strains of Magnetosprillum gtyphiswaldense MSR-1, a bacterial species that is amendable to genetic mutations. We combine our experimental results with a model describing the spectra. The model includes chain imperfections and misalignments following a Fisher distribution function, in addition to the intrinsic magnetic properties of the magnetosomes. Therefore, by applying the model to analyze the ferromagnetic resonance data, the distribution of orientations in the bulk sample can be retrieved in addition to the average magnetosome arrangement. In this way, we quantitatively characterize the magnetosome arrangement in both wild-type cells and Delta mamJ mutants, which exhibit differing magnetosome organization. Y1 - 2017 U6 - https://doi.org/10.1016/j.bpj.2017.06.031 SN - 0006-3495 SN - 1542-0086 VL - 113 SP - 637 EP - 644 PB - Cell Press CY - Cambridge ER - TY - JOUR A1 - Karpitschka, Stefan A1 - Liebig, Ferenc A1 - Riegler, Hans T1 - Marangoni Contraction of Evaporating Sessile Droplets of Binary Mixtures JF - Langmuir N2 - The Marangoni contraction of sessile drops of a binary mixture of a volatile and a nonvolatile liquid has been investigated experimentally and theoretically. The origin of the contraction is the locally inhomogeneous evaporation rate of sessile drops. This leads to surface tension gradients and thus to a Marangoni flow. Simulations show that the interplay of Marangoni flow, capillary flow, diffusive transport, and evaporative losses can establish a quasistationary drop profile with an apparent nonzero contact angle even if both liquid components individually wet the substrate completely. Experiments with different solvents, initial mass fractions, and gaseous environments reveal a previously unknown universal power-law relation between the apparent contact angle and the relative undersaturation of the ambient atmosphere: theta(app) similar to (RHeq - RH)(1/3). This experimentally observed power law is in quantitative agreement with simulation results. The exponent can also be inferred from a scaling analysis of the hydrodynamic-evaporative evolution equations of a binary mixture of liquids with different volatilities. Y1 - 2017 U6 - https://doi.org/10.1021/acs.langmuir.7b00740 SN - 0743-7463 VL - 33 SP - 4682 EP - 4687 PB - American Chemical Society CY - Washington ER - TY - JOUR A1 - Sprenger, Heike A1 - Erban, Alexander A1 - Seddig, Sylvia A1 - Rudack, Katharina A1 - Thalhammer, Anja A1 - Le, Mai Q. A1 - Walther, Dirk A1 - Zuther, Ellen A1 - Koehl, Karin I. A1 - Kopka, Joachim A1 - Hincha, Dirk K. T1 - Metabolite and transcript markers for the prediction of potato drought tolerance JF - Plant Biotechnology Journal N2 - Potato (Solanum tuberosum L.) is one of the most important food crops worldwide. Current potato varieties are highly susceptible to drought stress. In view of global climate change, selection of cultivars with improved drought tolerance and high yield potential is of paramount importance. Drought tolerance breeding of potato is currently based on direct selection according to yield and phenotypic traits and requires multiple trials under drought conditions. Marker-assisted selection (MAS) is cheaper, faster and reduces classification errors caused by noncontrolled environmental effects. We analysed 31 potato cultivars grown under optimal and reduced water supply in six independent field trials. Drought tolerance was determined as tuber starch yield. Leaf samples from young plants were screened for preselected transcript and nontargeted metabolite abundance using qRT-PCR and GC-MS profiling, respectively. Transcript marker candidates were selected from a published RNA-Seq data set. A Random Forest machine learning approach extracted metabolite and transcript markers for drought tolerance prediction with low error rates of 6% and 9%, respectively. Moreover, by combining transcript and metabolite markers, the prediction error was reduced to 4.3%. Feature selection from Random Forest models allowed model minimization, yielding a minimal combination of only 20 metabolite and transcript markers that were successfully tested for their reproducibility in 16 independent agronomic field trials. We demonstrate that a minimum combination of transcript and metabolite markers sampled at early cultivation stages predicts potato yield stability under drought largely independent of seasonal and regional agronomic conditions. KW - drought tolerance KW - machine learning KW - metabolite markers KW - potato (Solanum tuberosum) KW - prediction models KW - transcript markers Y1 - 2017 U6 - https://doi.org/10.1111/pbi.12840 SN - 1467-7644 SN - 1467-7652 VL - 16 IS - 4 SP - 939 EP - 950 PB - Wiley CY - Hoboken ER - TY - JOUR A1 - Behrendt, Felix Nicolas A1 - Schlaad, Helmut T1 - Metathesis polymerization of cystine-based macrocycles JF - Polymer Chemistry N2 - Macrocycles based on L-cystine were synthesized by ring-closing metathesis (RCM) and subsequently polymerized by entropy-driven ring-opening metathesis polymerization (ED-ROMP). Monomer conversion reached similar to 80% in equilibrium and the produced poly (ester-amine-disulfide-alkene)s exhibited apparent molar masses (M-w(app)) of up to 80 kDa and dispersities (D) of similar to 2. The polymers can be further functionalized with acid anhydrides and degraded by reductive cleavage of the main-chain disulfide. Y1 - 2016 U6 - https://doi.org/10.1039/c6py01864e SN - 1759-9954 SN - 1759-9962 VL - 8 IS - 2 SP - 366 EP - 369 PB - Royal Society of Chemistry CY - Cambridge ER - TY - JOUR A1 - Michalik-Onichimowska, Aleksandra A1 - Beitz, Toralf A1 - Panne, Ulrich A1 - Löhmannsröben, Hans-Gerd A1 - Riedel, Jens T1 - Microsecond mid-infrared laser pulses for atmospheric pressure laser ablation/ionization of liquid samples JF - Sensors and actuators : B, Chemical N2 - In many laser based ionization techniques with a subsequent drift time separation, the laser pulse generating the ions is considered as the start time to. Therefore, an accurate temporal definition of this event is crucial for the resolution of the experiments. In this contribution, the laser induced plume dynamics of liquids evaporating into atmospheric pressure are visualized for two distinctively different laser pulse widths, Delta t = 6 nanoseconds and Delta tau = 280 microseconds. For ns-pulses the expansion of the generated vapour against atmospheric pressure is found to lead to turbulences inside the gas phase. This results in spatial and temporal broadening of the nascent clouds. A more equilibrated expansion, without artificial smearing of the temporal resolution can, in contrast, be observed to follow mu s-pulse excitation. This leads to the counterintuitive finding that longer laser pulses results in an increased temporal vapour formation definition. To examine if this fume expansion also eventually results in a better definition of ion formation, the nascent vapour plumes were expanded into a linear drift tube ion mobility spectrometer (IMS). This time resolved detection of ion formation corroborates the temporal broadening caused by collisional impeding of the supersonic expansion at atmospheric pressure and the overall better defined ion formation by evaporation with long laser pulses. A direct comparison of the observed results strongly suggests the coexistence of two individual ion formation mechanisms that can be specifically addressed by the use of appropriate laser sources. KW - Laser ablation KW - Ion mobility spectrometry KW - Pulse duration KW - Plume KW - Ionization Y1 - 2016 U6 - https://doi.org/10.1016/j.snb.2016.06.155 SN - 0925-4005 VL - 238 SP - 298 EP - 305 PB - Elsevier CY - Lausanne ER - TY - JOUR A1 - Schmidt, Bernd A1 - Riemer, Martin T1 - Microwave-Promoted Pd-Catalyzed Synthesis of Dibenzofurans from Ortho-Arylphenols JF - Journal of Heterocyclic Chemistry N2 - ortho-Aryl phenols, synthesized via protecting group free Suzuki-Miyaura coupling of ortho-halophenols and arene boronic acids, undergo a cyclization to dibenzofurans via oxidative C-H activation. The reaction proceeds under microwave irradiation in short reaction times using catalytic amounts of Pd(OAc)(2) without additional ligands. Y1 - 2017 U6 - https://doi.org/10.1002/jhet.2704 SN - 0022-152X SN - 1943-5193 VL - 54 IS - 2 SP - 1287 EP - 1297 PB - Wiley CY - Hoboken ER - TY - JOUR A1 - Shainyan, Bagrat A. A1 - Belyakov, Alexander V. A1 - Sigolaev, Yurii F. A1 - Khramov, Alexander N. A1 - Kleinpeter, Erich T1 - Molecular Structure and Conformational Analysis of 1-Phenyl-1-X-1-Silacyclohexanes (X = F, Cl) by Electron Diffraction, Low-Temperature NMR, and Quantum Chemical Calculations JF - The journal of organic chemistry N2 - The molecular structure and conformational preferences of 1-phenyl-1-X-1-silacyclohexanes C5H10Si(Ph,X) (X = F (3), Cl (4)) were studied by gas-phase electron diffraction, low-temperature NMR spectroscopy, and high-level quantum chemical calculations. In the gas phase only three (3) and two (4) stable conformers differing in the axial or equatorial location of the phenyl group and the angle of rotation about the Si-C-ph bond (axi and axo denote the Ph group lying in or out of the X-Si-C-ph plane) contribute to the equilibrium. In 3 the ratio Ph-eq:Ph-axo:Ph-axi is 40(12):55(24):5 and 64:20:16 by experiment and theory, respectively. In 4 the ratio Ph-eq:Ph-axo is 79(15):21(15) and 71:29 by experiment and theory (M06-2X calculations), respectively. The gas-phase electron diffraction parameters are in good agreement with those obtained from theory at the M06-2X/aug-ccPVTZ and MP2/aug-cc-pVTZ levels. Unlike the case for M06-2X, MP2 calculations indicate that 3-Ph-eq conformer lies 0.5 kcal/mol higher than the 3-Ph-axo, conformer. As follows from QTAIM analysis, the phenyl group is more stable when it is located in the axial position but produces destabilization of the silacyclohexane ring: By low temperature NMR spectroscopy the six-membered ring interconversion could be frozen, at 103 K and the present conformational equilibria of 3 and 4 could be determined. The ratio of the conformers is 3-Ph-eq:3-Ph-ax = (75-77):(23-25) and 4-Ph-eq:4-Ph-ax = 82:18. Y1 - 2017 U6 - https://doi.org/10.1021/acs.joc.6b02538 SN - 0022-3263 VL - 82 IS - 1 SP - 461 EP - 470 PB - American Chemical Society CY - Washington ER - TY - JOUR A1 - Thirumalaikumar, Venkatesh P. A1 - Devkar, Vikas A1 - Mehterov, Nikolay A1 - Ali, Shawkat A1 - Ozgur, Rengin A1 - Turkan, Ismail A1 - Müller-Röber, Bernd A1 - Balazadeh, Salma T1 - NAC transcription factor JUNGBRUNNEN1 enhances drought tolerance in tomato JF - Plant Biotechnology Journal N2 - Water deficit (drought stress) massively restricts plant growth and the yield of crops; reducing the deleterious effects of drought is therefore of high agricultural relevance. Drought triggers diverse cellular processes including the inhibition of photosynthesis, the accumulation of cell-damaging reactive oxygen species and gene expression reprogramming, besides others. Transcription factors (TF) are central regulators of transcriptional reprogramming and expression of many TF genes is affected by drought, including members of the NAC family. Here, we identify the NAC factor JUNGBRUNNEN1 (JUB1) as a regulator of drought tolerance in tomato (Solanum lycopersicum). Expression of tomato JUB1 (SlJUB1) is enhanced by various abiotic stresses, including drought. Inhibiting SlJUB1 by virus-induced gene silencing drastically lowers drought tolerance concomitant with an increase in ion leakage, an elevation of hydrogen peroxide (H2O2) levels and a decrease in the expression of various drought-responsive genes. In contrast, overexpression of AtJUB1 from Arabidopsis thaliana increases drought tolerance in tomato, alongside with a higher relative leaf water content during drought and reduced H2O2 levels. AtJUB1 was previously shown to stimulate expression of DREB2A, a TF involved in drought responses, and of the DELLA genes GAI and RGL1. We show here that SlJUB1 similarly controls the expression of the tomato orthologs SlDREB1, SlDREB2 and SlDELLA. Furthermore, AtJUB1 directly binds to the promoters of SlDREB1, SlDREB2 and SlDELLA in tomato. Our study highlights JUB1 as a transcriptional regulator of drought tolerance and suggests considerable conservation of the abiotic stress-related gene regulatory networks controlled by this NAC factor between Arabidopsis and tomato. KW - Arabidopsis KW - tomato KW - transcription factor KW - drought KW - reactive oxygen species KW - DELLA Y1 - 2017 U6 - https://doi.org/10.1111/pbi.12776 SN - 1467-7644 SN - 1467-7652 VL - 16 IS - 2 SP - 354 EP - 366 PB - Wiley CY - Hoboken ER - TY - JOUR A1 - Charan, Himanshu A1 - Glebe, Ulrich A1 - Anand, Deepak A1 - Kinzel, Julia A1 - Zhu, Leilei A1 - Bocola, Marco A1 - Garakani, Tayebeh Mirzaei A1 - Schwaneberg, Ulrich A1 - Böker, Alexander T1 - Nano-thin walled micro-compartments from transmembrane protein-polymer conjugates JF - Soft matter N2 - The high interfacial activity of protein-polymer conjugates has inspired their use as stabilizers for Pickering emulsions, resulting in many interesting applications such as synthesis of templated micro-compartments and protocells or vehicles for drug and gene delivery. In this study we report, for the first time, the stabilization of Pickering emulsions with conjugates of a genetically modified transmembrane protein, ferric hydroxamate uptake protein component A (FhuA). The lysine residues of FhuA with open pore (FhuA Delta CVFtev) were modified to attach an initiator and consequently controlled radical polymerization (CRP) carried out via the grafting-from technique. The resulting conjugates of FhuA Delta CVFtev with poly(N-isopropylacrylamide) (PNIPAAm) and poly((2-dimethylamino) ethyl methacrylate) (PDMAEMA), the so-called building blocks based on transmembrane proteins (BBTP), have been shown to engender larger structures. The properties such as pH-responsivity, temperature-responsivity and interfacial activity of the BBTP were analyzed using UV-Vis spectrophotometry and pendant drop tensiometry. The BBTP were then utilized for the synthesis of highly stable Pickering emulsions, which could remain non-coalesced for well over a month. A new UV-crosslinkable monomer was synthesized and copolymerized with NIPAAm from the protein. The emulsion droplets, upon crosslinking of polymer chains, yielded micro-compartments. Fluorescence microscopy proved that these compartments are of micrometer scale, while cryo-scanning electron microscopy and scanning force microscopy analysis yielded a thickness in the range of 11.1 +/- 0.6 to 38.0 +/- 18.2 nm for the stabilizing layer of the conjugates. Such micro-compartments would prove to be beneficial in drug delivery applications, owing to the possibility of using the channel of the transmembrane protein as a gate and the smart polymer chains as trigger switches to tune the behavior of the capsules. Y1 - 2017 U6 - https://doi.org/10.1039/c6sm02520j SN - 1744-683X SN - 1744-6848 VL - 13 SP - 2866 EP - 2875 PB - Royal Society of Chemistry CY - Cambridge ER - TY - GEN A1 - Naolou, Toufik A1 - Rühl, Eckart A1 - Lendlein, Andreas T1 - Nanocarriers BT - Architecture, transport, and topical application of drugs for therapeutic use T2 - European Journal of Pharmaceutics and Biopharmaceutics Y1 - 2017 U6 - https://doi.org/10.1016/j.ejpb.2017.03.004 SN - 0939-6411 SN - 1873-3441 VL - 116 SP - 1 EP - 3 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Kleinpeter, Erich A1 - Heydenreich, Matthias A1 - Koch, Andreas A1 - Krtitschka, Angela A1 - Krüger, Tobias A1 - Linker, Torsten T1 - NMR spectroscopic conformational analysis of 4-methylene-cyclohexyl pivalateThe effect of sp(2) hybridization JF - Magnetic resonance in chemistry N2 - The conformational equilibrium of the axial/equatorial conformers of 4-methylene-cyclohexyl pivalate is studied by dynamic NMR spectroscopy in a methylene chloride/freon mixture. At 153K, the ring interconversion gets slow on the nuclear magnetic resonance timescale, the conformational equilibrium (-G degrees) can be examined, and the barrier to ring interconversion (G(#)) can be determined. The structural influence of sp(2) hybridization on both G degrees and G(#) of the cyclohexyl moiety can be quantified. KW - 4-methylene-cyclohexyl pivalate KW - conformational analysis KW - dynamic NMR spectroscopy KW - exo-methylene conformational effect at cyclohexane KW - quantum chemical calculations Y1 - 2017 U6 - https://doi.org/10.1002/mrc.4630 SN - 0749-1581 SN - 1097-458X VL - 55 SP - 1073 EP - 1078 PB - Wiley CY - Hoboken ER - TY - JOUR A1 - Farhan, Muhammad A1 - Rudolph, Tobias A1 - Nöchel, Ulrich A1 - Yan, Wan A1 - Kratz, Karl A1 - Lendlein, Andreas T1 - Noncontinuously Responding Polymeric Actuators JF - ACS applied materials & interfaces N2 - Reversible movements of current polymeric actuators stem from the continuous response to signals from a controlling unit, and subsequently cannot be interrupted without stopping or eliminating the input trigger. Here, we present actuators based on cross-linked blends of two crystallizable polymers capable of pausing their movements in a defined manner upon continuous cyclic heating and cooling. This noncontinuous actuation can be adjusted by varying the applied heating and cooling rates. The feasibility of these devices for technological applications was shown in a 140 cycle experiment of free-standing noncontinuous shape shifts, as well as by various demonstrators. KW - soft robotics KW - polymer actuators KW - thermo-sensitivity KW - shape shifting materials KW - crystallization behavior Y1 - 2017 U6 - https://doi.org/10.1021/acsami.7b11316 SN - 1944-8244 VL - 9 SP - 33559 EP - 33564 PB - American Chemical Society CY - Washington ER - TY - JOUR A1 - Unuabonah, Emmanuel Iyayi A1 - Kolawole, Matthew O. A1 - Agunbiade, Foluso O. A1 - Omorogie, Martins O. A1 - Koko, Daniel T. A1 - Ugwuja, Chidinma G. A1 - Ugege, Leonard E. A1 - Oyejide, Nicholas E. A1 - Günter, Christina A1 - Taubert, Andreas T1 - Novel metal-doped bacteriostatic hybrid clay composites for point-of-use disinfection of water JF - Journal of Environmental Chemical Engineering N2 - This study reports the facile microwave-assisted thermal preparation of novel metal-doped hybrid clay composite adsorbents consisting of Kaolinite clay, Carica papaya seeds and/or plantain peels (Musa paradisiaca) and ZnCl2. Fourier Transformed IR spectroscopy, X-ray diffraction, Scanning Electron Microscopy and Brunauer-Emmett-Teller (BET) analysis are employed to characterize these composite adsorbents. The physicochemical analysis of these composites suggests that they act as bacteriostatic rather than bacteriacidal agents. This bacterostactic action is induced by the ZnO phase in the composites whose amount correlates with the efficacy of the composite. The composite prepared with papaya seeds (PS-HYCA) provides the best disinfection efficacy (when compared with composite prepared with Musa paradisiaca peels-PP-HYCA) against gram-negative enteric bacteria with a breakthrough time of 400 and 700 min for the removal of 1.5 x10(6) cfu/mL S. typhi and V. cholerae from water respectively. At 10(3) cfu/mL of each bacterium in solution, 2 g of both composite adsorbents kept the levels the bacteria in effluent solutions at zero for up to 24 h. Steam regeneration of 2 g of bacteria-loaded Carica papaya prepared composite adsorbent shows a loss of ca. 31% of its capacity even after the 3rd regeneration cycle of 25 h of service time. The composite adsorbent prepared with Carica papaya seeds will be useful for developing simple point-of-use water treatment systems for water disinfection application. This composite adsorbent is comparatively of good performance and shows relatively long hydraulic contact times and is expected to minimize energy intensive traditional treatment processes. KW - Kaolinite KW - Composites KW - Bacteria KW - Breakthrough time KW - Regeneration Y1 - 2017 U6 - https://doi.org/10.1016/j.jece.2017.04.017 SN - 2213-3437 VL - 5 SP - 2128 EP - 2141 PB - Elsevier CY - Oxford ER -