TY - JOUR A1 - Obertegger, Ulrike A1 - Cieplinski, Adam A1 - Raatz, Michael A1 - Colangeli, Pierluigi T1 - Switching between swimming states in rotifers - case study Keratella cochlearis JF - Marine and Freshwater Behaviour and Physiology N2 - Swimming is of vital importance for aquatic organisms because it determines several aspects of fitness, such as encounter rates with food, predators, and mates. Generally, rotifer swimming speed is measured by manual tracking of the swimming paths filmed in videos. Recently, an open-source package has been developed that integrates different open-source software and allows direct processing and analysis of the swimming paths of moving organisms. Here, we filmed groups of females and males of Keratella cochlearis separately and in a mixed experimental setup. We extracted movement trajectories and swimming speeds and applied the classification method random forest to assign sex to individuals of the mixed setup. Finally, we used advanced statistical methods of movement ecology, namely a hidden Markov model, to investigate swimming states of females and males. When not discriminating swimming states, females swam faster than males, while when discriminating states males swam faster. Specifically, females and males showed two main states of movement with many individuals switching between states resulting in four modes of swimming. We suggest that switching between states is related to predator avoidance. Males of K. cochlearis especially exhibited switching between turning in a restricted area and swimming over longer distances. No mating or other male-female interactions were observed. Our study elucidates the steps necessary for automatic analysis of rotifer trajectories with open-source software. Application of sophisticated software and analytical models will broaden our understanding of zooplankton ecology from the individual to the population level. KW - BEMOVI KW - dwarf males KW - hidden markov model KW - Monogononta KW - swimming modes Y1 - 2018 U6 - https://doi.org/10.1080/10236244.2018.1503541 SN - 1023-6244 SN - 1029-0362 VL - 51 IS - 3 SP - 159 EP - 173 PB - Routledge, Taylor & Francis Group CY - Abingdon ER - TY - JOUR A1 - Solovyev, Nikolay A1 - Prakash, N. Tejo A1 - Bhatia, Poonam A1 - Prakash, Ranjana A1 - Drobyshev, Evgenii J. A1 - Michalke, Bernhard T1 - Selenium-rich mushrooms cultivation on a wheat straw substrate from seleniferous area in Punjab, India JF - Journal of trace elements in medicine and biology N2 - Intensive rice-wheat cultivation cycle in Northern belt of India in general and in the State of Punjab in particular results in large volumes of straw and other post-harvest residue annually. The agricultural area, bordering the districts of Nawanshahr and Hoshiarpur, is popularly known as the seleniferous belt of India. The agri-residues, generated in seleniferous region of this state, are observed to contain significantly high concentration of selenium (Se). The present study was aimed to evaluate the Se uptake by different mushroom species: Pleurotus sajorcaju, Pleurotus ostreatus, Pleurotus citrinopileatus, Agaricus bisporus, and Volvariella volvacea, cultivated on Se-rich wheat and paddy straw from the seleniferous region. Wheat (Pleurotus species and A. bisporus) and paddy straw (V. volvacea) was inoculated with the mycelium spawn and left for 7-20 days, depending on the species, to grow. Control mushrooms were grown analogously using the agricultural residues from non-seleniferous area of the State of Punjab. All fruiting bodies were collected and analyzed in triplicate. Se was quantified using inductively coupled plasma sector field mass spectrometry. The Se accumulation was high in all species under study, being the highest in A. bisporus (1396 mu g/g vs. 46.8 mu g/g in controls - dry weight) and V. volvacea (231 mu g/g vs. 3.77 mu g/g - dry weight). The observed biological efficiency and total yield for all mushroom species showed good and unaltered productivity in Se-rich conditions, if compared to the controls. The Se-rich mushrooms can be prospective Se-supplements sourcing and biofortified foods, providing readily bioavailable and accessible Se for the diets deficient of this biologically essential element. KW - Selenium KW - Mushrooms KW - Cultivation KW - Bioaccumulation KW - Seleniferous area KW - Supplements Y1 - 2018 U6 - https://doi.org/10.1016/j.jtemb.2018.07.027 SN - 0946-672X VL - 50 SP - 362 EP - 366 PB - Elsevier CY - Jena ER - TY - JOUR A1 - Dittmann, Thea A1 - Heinken, Thilo A1 - Schmidt, Marcus T1 - Die Wälder von Magdeburgerforth (Fläming, Sachsen-Anhalt) T1 - The forests of Magdeburgerforth (Flaming, NE Germany) BT - eine Wiederholungsuntersuchung nach sechs Jahrzehnten BT - a resurvey study after six decades JF - Tuexenia : Mitteilungen der Floristisch-Soziologischen Arbeitsgemeinschaft N2 - In einem rund 2.200 ha großen Waldgebiet bei Magdeburgerforth (Fläming, Sachsen-Anhalt) wurden 1948 bis 1950 von Harro Passarge 120 Vegetationsaufnahmen sowie eine Vegetationskartierung erstellt. Das Gebiet zeichnet sich durch eine große Vielfalt an Waldtypen aus den Verbänden Agrostio-Quercion petraeae, Alnion glutinosae, Alnion incanae, Carpinion betuli, Dicrano-Pinion und Quercion roboris aus. Daher und weil viele der heute in Wäldern wirksamen Prozesse (z. B. Stickstoffeintrag, Klimawandel) vor 60 Jahren noch nicht spürbar waren, bietet sich das Gebiet für eine Wiederholungsuntersuchung besonders an. Da die Aufnahmeflächen von Passarge nicht punktgenau verortet waren, wurden im Jahr 2014 in einem über die Forstabteilungen und die Vegetationskarte definierten Suchraum immer die der Erstaufnahme ähnlichsten Waldbestände erfasst. Insgesamt konnten 97 (81 %) der Aufnahmen wiederholt werden. Vegetationsveränderungen werden mithilfe einer NMDS-Ordination, der Gegenüberstellung von α -Diversität, Zeigerwerten und Waldbindungskategorien für die beiden Aufnahmezeitpunkte sowie über die Identifikation von Gewinner- und Verlierer-Arten analysiert. Auch wenn methodenbedingt bei der Wiederholungsuntersuchung nur die jeweils geringstmögliche Vegetationsveränderung abgebildet wird, konnten Ergebnisse erzielt werden, die mit denen quasi permanenter Plots übereinstimmen. Die beobachteten allgemeinen Trends (Eutrophierung, Sukzession nach Nutzungswandel, Verlust lichtliebender und magerkeitszeigender Arten, Ausbreitung von stickstoffliebenden Arten und mesophilen Waldarten, Einwanderung von Neophyten, keine generelle Abnahme der Artenzahl) stimmen gut mit den in zahlreichen Studien aus mitteleuropäischen Wäldern festgestellten überein. Durch das von nassen bis trockenen sowie von bodensauer-nährstoffarmen bis zu relativ basenreichen Böden reichende Standortsspektrum innerhalb des Untersuchungsgebietes konnte aber – deutlicher als in den meisten bisherigen Fallstudien – gezeigt werden, dass sich die Resilienz der Wälder gegenüber Vegetationsveränderung je nach Ausgangsgesellschaft stark unterscheidet und jeweils unterschiedliche Treiber wirksam sind. Stellario-Carpinetum und Luzulo-Quercetum erwiesen sich als relativ stabil, und auch in den Feuchtwäldern des Circaeo-Alnetum gab es trotz eines Artenwechsels wenig Hinweise auf Umweltveränderungen. Dagegen wiesen die Wälder nährstoffarmer Standorte (Sphagno-Alnetum, Betulo-Quercetum, Dicrano-Pinion) viele Verliererarten und eine starke Eutrophierungstendenz auf. Die in besonderem Maße von historischen Waldnutzungsformen abhängigen thermophilen Wälder und die Flechten-Kiefernwälder gingen weitgehend verloren. N2 - Between 1948 and 1950 the German phytosociologist Harro Passarge conducted 120 relevés in a 2,200 ha large forest area near Magdeburgerforth (Fläming, Saxony-Anhalt, NE Germany). The study area is characterized by a remarkable diversity of forest communities of the alliances Agrostio- Quercion petraeae, Alnion glutinosae, Alnion incanae, Carpinion betuli, Dicrano-Pinion and Quercion roboris. Because of this broad ecological spectrum, and because many processes which impact Central European forests today (nitrogen deposition, climate change) were not noticeable at the date of the first survey, it provides a good opportunity for a resurvey study after 60 years. As the position of Passarge’s relevés were not marked in a map, in the 2014 resurvey we sampled the most similar forest stands within a search area defined by the forest compartment and the Passarge vegetation map. In this way, 97 (81%) of the relevés could be repeated. Vegetation change was analysed by NMDS ordination and the comparison of α diversity, Ellenberg indicator values and linkage to forest habitats of species from both censuses, as well as by the identification of winner and loser species. Although, due to the methodology, only the smallest possible vegetation change was indicated, we nevertheless gained results which conform to those of resurveys based on quasi-permanent plots. The main trends (eutrophication, succession after management change, loss of plant species that are light- demanding and linked to oligotrophic sites, spread of nitrophilous and mesophilous forest species, immigration of neophytes, no general decline in species richness) are in agreement with the results of several other resurvey studies in Central and Western European forests. Because of the wide spectrum of habitats within the study area (from wet to dry, as well as from acidic and nutrient-poor to relatively base-rich) we could demonstrate more clearly than in previous studies that the resilience of forests to vegetation change differs strongly according to the initial forest type, and that different drivers of tem- poral changes are active. Mesophilous forests (Stellario-Carpinetum and Luzulo-Quercetum) turned out to be relatively stable, while Circaeo-Alnetum forests also showed few signs of environmental change despite some species turnover. In contrast, forests of nutrient-poor habitats (Sphagno-Alnetum, Betulo-Quercetum, Dicrano-Pinion) were characterized by many loser species and a strong tendency towards eutrophication. Thermophilous forests and lichen-pine forests, which are especially dependent on historical forest management techniques, largely disappeared. KW - initial site conditions KW - nitrogen deposition KW - past land use KW - quasi-permanent plots KW - vegetation change KW - winner and loser species Y1 - 2018 U6 - https://doi.org/10.14471/2018.38.009 SN - 0722-494X IS - 38 SP - 11 EP - 42 PB - Floristisch-Soziologische Arbeitsgemeinschaft CY - Göttingen ER - TY - JOUR A1 - Zhao, Liming A1 - Xia, Yan A1 - Wu, Xiao-Yuan A1 - Schippers, Jos H. M. A1 - Jing, Hai-Chun T1 - Phenotypic analysis and molecular markers of leaf senescence JF - Plant Senescence: Methods and Protocols N2 - The process of leaf senescence consists of the final stage of leaf development. It has evolved as a mechanism to degrade macromolecules and micronutrients and remobilize them to other developing parts of the plant; hence it plays a central role for the survival of plants and crop production. During senescence, a range of physiological, morphological, cellular, and molecular events occur, which are generally referred to as the senescence syndrome that includes several hallmarks such as visible yellowing, loss of chlorophyll and water content, increase of ion leakage and cell death, deformation of chloroplast and cell structure, as well as the upregulation of thousands of so-called senescence-associated genes (SAGs) and downregulation of photosynthesis-associated genes (PAGs). This chapter is devoted to methods characterizing the onset and progression of leaf senescence at the morphological, physiological, cellular, and molecular levels. Leaf senescence normally progresses in an age-dependent manner but is also induced prematurely by a variety of environmental stresses in plants. Focused on the hallmarks of the senescence syndrome, a series of protocols is described to asses quantitatively the senescence process caused by developmental cues or environmental perturbations. We first briefly describe the senescence process, the events associated with the senescence syndrome, and the theories and methods to phenotype senescence. Detailed protocols for monitoring senescence in planta and in vitro, using the whole plant and the detached leaf, respectively, are presented. For convenience, most of the protocols use the model plant species Arabidopsis and rice, but they can be easily extended to other plants. KW - Leaf senescence KW - Visible yellowing KW - Chlorophyll KW - Ion leakage KW - Cell death KW - Senescence-associated genes (SAGs) KW - Arabidopsis KW - Rice Y1 - 2018 SN - 978-1-4939-7672-0 SN - 978-1-4939-7670-6 U6 - https://doi.org/10.1007/978-1-4939-7672-0_3 SN - 1064-3745 SN - 1940-6029 VL - 1744 SP - 35 EP - 48 PB - Humana Press Inc. CY - Totowa ER - TY - JOUR A1 - Perillon, Cecile A1 - van de Weyer, Klaus A1 - Päzolt, Jens A1 - Kasprzak, Peter A1 - Hilt, Sabine T1 - Changes in submerged macrophyte colonization in shallow areas of an oligo-mesotrophic lake and the potential role of groundwater JF - Limnologica : ecology and management of inland waters N2 - Groundwater influx can significantly contribute to nutrient budgets of lakes and its influence is strongest in shallow littoral areas. In oligo-or mesotrophic systems, additional nutrient supply by groundwater influx may affect benthic primary producers and their interactions. Potential changes can be expected in community composition, biomass, stoichiometry and interactions between submerged macrophytes and epiphyton. KW - Seepage KW - Eutrophication KW - Charophytes KW - Periphyton KW - Nutrients KW - Littoral Y1 - 2018 U6 - https://doi.org/10.1016/j.limno.2017.03.002 SN - 0075-9511 SN - 1873-5851 VL - 68 SP - 168 EP - 176 PB - Elsevier CY - Jena ER - TY - JOUR A1 - Machatschek, Rainhard Gabriel A1 - Schulz, Burkhard A1 - Lendlein, Andreas T1 - The influence of pH on the molecular degradation mechanism of PLGA JF - MRS Advances N2 - Poly[(rac-lactide)-co-glycolide] (PLGA) is used in medicine to provide mechanical support for healing tissue or as matrix for controlled drug release. The properties of this copolymer depend on the evolution of the molecular weight of the material during degradation. which is determined by the kinetics of the cleavage of hydrolysable bonds. The generally accepted description of the degradation of PLGA is a random fragmentation that is autocatalyzed by the accumulation of acidic fragments inside the bulk material. Since mechanistic studies with lactide oligomers have concluded a chain-end scission mechanism and monolayer degradation experiments with polylactide found no accelerated degradation at lower pH, we hypothesize that the impact of acidic fragments on the molecular degradation kinetics of PLGA is overestimated By means of the Langmuir monolayer degradation technique. the molecular degradation kinetics of PLGA at different pH could be determined. Protons did not catalyze the degradation of PLGA. The molecular mechanism at neutral pH and low pH is a combination of random and chainend-cut events, while the degradation under strongly alkaline conditions is determined by rapid chainend cuts. We suggest that the degradation of bulk PLGA is not catalyzed by the acidic degradation products. Instead. increased concentration of small fragments leads to accelerated mass loss via fast chain-end cut events. In the future, we aim to substantiate the proposed molecular degradation mechanism of PLGA with interfacial rheology. Y1 - 2018 U6 - https://doi.org/10.1557/adv.2018.602 SN - 2059-8521 VL - 3 IS - 63 SP - 3883 EP - 3889 PB - Cambridge Univ. Press CY - New York ER - TY - JOUR A1 - Wischke, Christian A1 - Baehr, Elen A1 - Racheva, Miroslava A1 - Heuchel, Matthias A1 - Weigel, Thomas A1 - Lendlein, Andreas T1 - Surface immobilization strategies for tyrosinase as biocatalyst applicable to polymer network synthesis JF - MRS Advances N2 - Enzymes have recently attracted increasing attention in material research based on their capacity to catalyze the conversion of polymer-bound moieties for synthesizing polymer networks, particularly bulk hydrogels. hi this study. the surface immobilization of a relevant enzyme. mushroom tyrosinase, should be explored using glass as model surface. In a first step. the glass support was functionalized with silanes to introduce either amine or carboxyl groups, as confirmed e.g. by X-ray photoelectron spectroscopy. By applying glutaraldehyde and EDC/NHS chemistry, respectively, surfaces have been activated for subsequent successful coupling of tyrosinase. Via protein hydrolysis and amino acid characterization by HPLC, the quantity of bound tyrosinase was shown to correspond to a full surface coverage. Based on the visualized enzymatic conversion of a test substrate at the glass support. the functionalized surfaces may be explored for surface-associated material synthesis in the future. Y1 - 2018 U6 - https://doi.org/10.1557/adv.2018.630 SN - 2059-8521 VL - 3 IS - 63 SP - 3875 EP - 3881 PB - Cambridge Univ. Press CY - New York ER - TY - JOUR A1 - Farhan, Muhammad A1 - Rudolph, Tobias A1 - Kratz, Karl A1 - Lendlein, Andreas T1 - Torsional Fiber Actuators from Shape-memory Polymer JF - MRS Advances N2 - Humanoid robots, prosthetic limbs and exoskeletons require soft actuators to perform their primary function, which is controlled movement. In this wont we explored whether crosslinked poly[ethylene-co-(vinyl acetate)] (cPEVA) fibers, with different vinyl acetate (VA) content can serve as torsional fiber actuators. exhibiting temperature controlled reversible rotational changes. Broad melting transitions ranging from 50 to 90 degrees C for cPEVA18-165 or from 40 to 80 degrees C for cPEVA28-165 fibers in combination with complete crystallization at temperatures around 10 degrees C make them suitable actuating materials with adjustable actuation temperature ranges between 10 and 70 degrees C during repetitive cooling and heating. The obtained fibers exhibited a circular cross section with diameters around 0.4 +/- 0.1 mm, while a length of 4 cm was employed for the investigation of reversible rotational actuation after programming by twist insertion using 30 complete rotations at a temperature above melting transition. Repetitive heating and cooling between 10 to 60 degrees C or 70 degrees C of one-end-tethered programmed fibers revealed reversible rotations and torsional force. During cooling 3 +/- 1 complete rotations (Delta theta(r) = + 1080 +/- 360 degrees) in twisting direction were observed, while 4 +/- 1 turns in the opposite direction (Delta theta(r) = - 1440 +/- 1360 degrees) were found during heating. Such torsional fiber actuators, which are capable of approximately one rotation per cm fiber length, can serve as miniaturized rotary motors to provide rotational actuation in futuristic humanoid robots. Y1 - 2018 U6 - https://doi.org/10.1557/adv.2018.621 SN - 2059-8521 VL - 3 IS - 63 SP - 3861 EP - 3868 PB - Cambridge Univ. Press CY - New York ER - TY - JOUR A1 - Yan, Wan A1 - Fang, Liang A1 - Nöchel, Ulrich A1 - Gould, Oliver E. C. A1 - Behl, Marc A1 - Kratz, Karl A1 - Lendlein, Andreas T1 - Investigating the roles of crystallizable and glassy switching segments within multiblock copolymer shape-memory materials JF - MRS Advances N2 - The variation of the molecular architecture of multiblock copolymers has enabled the introduction of functional behaviour and the control of key mechanical properties. In the current study, we explore the synergistic relationship of two structural components in a shape-memory material formed of a multiblock copolymer with crystallizable poly(epsilon-caprolactone) and crystallizable polyfoligo(3S-iso-butylmorpholine-2,5-dione) segments (PCL-PIBMD). The thermal and structural properties of PCL-PIBMD films were compared with PCI.-PU and PMMD-PU investigated by means of DSC, SAXS and WARS measurements. The shape-memory properties were quantified by cyclic, thermomechanical tensile tests, where deformation strains up to 900% were applied for programming PCL-PIBMD films at 50 degrees C. Toluene vapor treatment experiments demonstrated that the temporary shape was fixed mainly by glassy PIBMD domains at strains lower than 600% with the PCL contribution to fixation increasing to 42 +/- 2% at programming strains of 900% This study into the shape-memory mechanism of PCL-PIBMD provides insight into the structure function relation in multiblock copolymers with both crystallizable and glassy switching segments. Y1 - 2018 U6 - https://doi.org/10.1557/adv.2018.590 SN - 2059-8521 VL - 3 IS - 63 SP - 3741 EP - 3749 PB - Cambridge Univ. Press CY - New York ER - TY - JOUR A1 - Krüger-Genge, Anne A1 - Dietze, Stefanie A1 - Yan, Wan A1 - Liu, Yue A1 - Fang, Liang A1 - Kratz, Karl A1 - Lendlein, Andreas A1 - Jung, Friedrich T1 - Endothelial cell migration, adhesion and proliferation on different polymeric substrates JF - Clinical hemorheology and microcirculation : blood flow and vessels N2 - BACKGROUND: The formation of a functionally-confluent endothelial cell (EC) monolayer affords proliferation of EC, which only happens in case of appropriate migratory activity. AIM OF THE STUDY: The migratory pathway of human umbilical endothelial cells (HUVEC) was investigated on different polymeric substrates. MATERIAL AND METHODS: Surface characterization of the polymers was performed by contact angle measurements and atomic force microscopy under wet conditions. 30,000 HUVEC per well were seeded on polytetrafluoroethylene (PTFE) (theta(adv) = 119 degrees +/- 2 degrees), on low-attachment plate LAP (theta(adv) = 28 degrees +/- 2 degrees) and on polystyrene based tissue culture plates (TCP, theta(adv) = 22 degrees +/- 1 degrees). HUVEC tracks (trajectories) were recorded by time lapse microscopy and the euclidean distance (straight line between starting and end point), the total distance and the velocities of HUVEC not leaving the vision field were determined. RESULTS: On PTFE, 42 HUVEC were in the vision field directly after seeding. The mean length of single migration steps (SML) was 6.1 +/- 5.2 mu m, the mean velocity (MV) 0.40 +/- 0.3 mu m.min(-1) and the complete length of the trajectory (LT) was 710 +/- 440 mu m. On TCP 82 HUVEC were in the vision field subsequent to seeding. The LT was 840 +/- 550 mu m, the SML 6.1 +/- 5.2 mu m and the MV 0.44 +/- 0.3 mu m.min(-1). The trajectories on LAP differed significantly in respect to SML (2.4 +/- 3.9 mu m, p <0.05), the MV (0.16 +/- 0.3 mu m.min(-1), p <0.05) and the LT (410 +/- 300 mu m, p <0.05), compared to PTFE and TCP. Solely on TCP a nearly confluent EC monolayer developed after three days. While on TCP diffuse signals of vinculin were found over the whole basal cell surface organizing the binding of the cells by focal adhesions, on PTFE vinculin was merely arranged at the cell rims, and on the hydrophilic material (LAP) no focal adhesions were found. CONCLUSION: The study revealed that the wettability of polymers affected not only the initial adherence but also the migration of EC, which is of importance for the proliferation and ultimately the endothelialization of polymer-based biomaterials. KW - Endothelial cells KW - migration KW - polymer-based biomaterials KW - cytokine release Y1 - 2019 U6 - https://doi.org/10.3233/CH-189317 SN - 1386-0291 SN - 1875-8622 VL - 70 IS - 4 SP - 511 EP - 529 PB - IOS Press CY - Amsterdam ER -