Root hemiparasites suppress invasive alien clonal plants: evidence from a cultivation experiment

Alien invasive plants threaten biodiversity by rapid spread and competitive exclusion of native plant species. Especially, tall clonal invasives can rapidly attain strong dominance in vegetation. Root-hemiparasitic plants are known to suppress the growth of clonal plants by the uptake of resources from their below-ground organs and reduce their abundance. However, root-hemiparasites’ ability to interact with alien clonal plants has not yet been tested. We explored the interactions between native root-hemiparasitic species, Melampyrum arvense and Rhinanthus alectorolophus and invasive aliens, Solidago gigantea and Symphyotrichum lanceolatum. We investigated the haustorial connections and conducted a pot experiment. We used seeds from wild hemiparasite populations and those cultivated in monostands of the invasive plants to identify a possible selection of lineages with increased compatibility with these alien hosts. The hemiparasitic species significantly suppressed the growth of the invasive plants. Melampyrum inflicted the most substantial growth reduction on Solidago (78%), followed by Rhinanthus (49%). Both hemiparasitic species reduced Symphyotrichum biomass by one-third. Additionally, Melampyrum reduced the shoot density of both host species. We also observed some transgenerational effects possibly facilitating the growth of hemiparasites sourced from subpopulations experienced with the host. Native root hemiparasites can effectively decrease alien clonal plants’ biomass production and shoot density. The outcomes of these interactions are species-specific and may be associated with the level of clonal integration of the hosts. The putative selection of lineages with higher performance when attached to the invasive novel hosts may increase hemiparasites’ efficiency in future biocontrol applications

Aligned nanofibres made of poly(3-hydroxybutyrate) grafted to hyaluronan for potential healthcare applications

In this work, a hybrid copolymer consisting of poly(3-hydroxybutyrate) grafted to hyaluronic acid (HA) was synthesised and characterised. Once formed, the P(3HB)-g-HA copolymer was soluble in water allowing a green electrospinning process. The diameters of nanofibres can be tailored by simply varying the Mw of polymer. The optimization of the process allowed to produce fibres of average diameter in the range of 100-150 nm and low polydispersity. The hydrophobic modification has not only increased the fibre diameter, but also the obtained layers were homogenous. At the nanoscale, the hybrid copolymer exhibited an unusual hairy topography. Moreover, the hardness and tensile properties of the hybrid were found to be superior compared to fibres made of unmodified HA. Particularly, this reinforcement was achieved at the longitudinal direction. Additionally, this work reports the use in the composition of a water-soluble copolymer containing photo cross-linkable moieties to produce insoluble materials post-electrospinning. The derivatives as well as their nanofibrous mats retain the biocompatibility of the natural polymers used for the fabrication

Popularization of history at the example of Lidice and Terezin

The essence of bachelor thesis Popularization of history at the example of Lidice and Terezín is to define the methods of presentation and popularization of Lidice Memorial and Terezín Memorial. The aim of the theoretical framework is mainly to outline the topic of collective memory in it´s basic forms. The topic continues with definitions of collective memory products as are collective trauma and politics of memory. The separate chapter is dedicated to the bearers of memory among which are museums, memorials, books, movies and internet. Last part is focused on historical context. The purpose of the practical framework is to apply the theoretical base on the mentioned memorials and to analyze their activities, which are helping to popularize history. The thesis presents form and appearance of the both memorials Terezín and Lidice, their projects, education programs and also movie and book production

Využití bylin v procesu úsporného hospodaření s vodou

The presented master study is focused on sustainable rain water management with emphasis on proper use of plants in the process. This thesis connects information from foreign countries and puts them into context of Czechclimatic conditions and Czechlegal and technical standards. It defines term “dešťový záhon“ (rain flower bed) as a landscape element for rainwater infiltration that combines aesthetical, ecological and water management functions. Technical aspect and assortment of usable plant species is critically evaluated. Suitable technical variants are “vsakovací průleh” (rain garden), “vsakovací průleh s rýhou” (bioretencion system) a “vsakovací průleh s rýhou a regulovaným odtokem” (bioretencion system). The study includes also few examples of realized rain water management solutions. Drought tolerant species looks surprisingly as most promising for use in “rain flower beds“. Combination of annual, biennial etc. plants is possible; however perennials are most promising, while shrubs and trees usage is limited. “Rain flower bed“ can be established by plantingor sowing. Both having its pros and cons the combination of these two approaches is apparently best, because sowing allows reduce initial costs of new greenery, while planted perennials prevents erosion and operate as structural plants. Additionally 30 plant species were tested, whether they are usable for direct sowing. Experiment was established within the grant project IGA - ZF/2018 - AP001 on April 2018 in Mendeleum grounds of Faculty of Horticulture, Lednice. Preliminary results show low germination rates that are significantly dependent on climatic conditions. Of the 30 only six can recommend for now: Achillea ptarmica, Asclepias tuberosa, Cichorium intybus, Coreopsis lanceolata ´Sterntaller´, Phuopsis stylosa, Oenothera biennis. Better results can be probably achieved by sowing plants in autumn, however results of the autumn part of the experiment will be known after submission of this work

Bestimmung der Dickenzuschläge für wetterfesten Stahl im Brückenbau

The corrosion rate of the weathering steel is considerably lower than that of the standard carbon steel. Nevertheless possible effects of corrosion losses on reliable service of the structure throughout the designed service life should be considered when designing the structures. In practice, the effects of the expected corrosion losses are typically eliminated by corrosion allowances which are added to the thickness of the element calculated in static analyses. This paper introduces a new method used for calculation of corrosion allowances on weathering steel bridges. This will be explained using an example of a bridge structure.Die Korrosionsgeschwindigkeiten von wetterfestem Stahl sind im Vergleich mit herkömmlichem Kohlenstoffstahl erheblich niedriger. Trotzdem muss beim Konstruktionsentwurf ein möglicher Einfluss von Korrosion auf die zuverlässig funktionierende Konstruktion für den gesamten Zeitraum ihrer geplanten Nutzungsdauer berücksichtigt werden. Bei der praktischen Gestaltung wird der Einfluss der angenommenen Korrosionsverluste für gewöhnlich über Dickenzuschläge eliminiert, welche zur Dicke der Elemente, die durch statische Berechnung ermittelt wurde, addiert werden. Im vorliegenden Artikel wird eine neue Methode zur Berechnung der Dickenzuschläge angeführt, die bei Entwürfen für Brückenkonstruktionen aus wetterfestem Stahl genutzt werden kann. Dies wird an Hand eines Modellbeispiels erklärt.Web of Science82858858

The Effects of Electric Field Dynamics on the Quality of Large-Area Nanofibrous Layers

This paper presents technological modifications of an electrostatic spinning device, which significantly increase the thickness homogeneity (i.e., quality) of produced layers by creating auxiliary dynamic electric fields in the vicinity of the spinning and collector electrodes. A moving body was installed above the needleless spinning electrode, which destabilized the standing wave occurring on the free surface of the spinning solution. Furthermore, an endless belt design was used for the collector electrode instead of a roll-to-roll design, which made it possible to substantially increase the surface speed of the substrate and, therefore, the dynamics of the electric field at the place of collection of the fibers being spun. As a result, the coefficient of variation of the area weight of 912 samples cut out from the deposited nanofibrous layer, which was (1000 × 500) mm2 in size and had an average area weight of (17.2 ± 0.8) g/m2, was less than 4.5%. These results were obtained only when the dynamics of both the spinning and collector electrodes were increased at the same time. These modifications resulted in a significant increase in the quality of deposited nanofibrous layers up to the standard required for their use in pharmaceutical applications

Porovnání biologických efektů bakteriálního a syntetického melaninu u neuroblastomových buněk.

Melanins belong to a group of pigments of different structure and origin. They can be produced synthetically or isolated from living organisms. A number of studies have reported testing of various melanins in neurological studies providing different outcomes. Because the structure of melanins can have an effect on obtained results in cell toxicity studies, we present here our original study which aimed to compare the biological effects of bacterial melanin (biotechnologically obtained from B. thuringiensis) with that of synthetic melanin in neuroblastoma cells. Both melanins were structurally characterized in detail. After melanin treatment (0–200 μg/mL), cell viability, glutathione levels, cell morphology and respiration were assessed in SH-SY5Y cells. The structural analysis showed that bacterial melanin is more hydrophilic according to the presence of larger number of –OH moieties. After melanin treatment, we found that synthetic melanin at similar dosage caused always larger cell impairment compared to bacterial melanin. In addition, more severe toxic effect of synthetic melanin was found in mitochondria. In general, we conclude that more hydrophilic, bacterial melanin induced lower toxicity in neuroblastoma cells in comparison to synthetic melanin. Our findings can be useable for neuroscientific studies estimating the potential use for study of neuroprotection, neuromodulation or neurotoxicity.Melaniny patří do skupiny heterogenních pigmentů různé struktury a původu. Lze je vyrobit synteticky nebo je lze izolovat z živých organismů. Struktura melaninů může mít vliv na dosažené experimentální výsledky. Hlavním cílem naší studie bylo porovnat biologické účinky bakteriálního melaninu (biotechnologicky získaného z B. thuringiensis) se syntetickým melaninem. K tomuto in vitro testování byla využita neuroblastomová buněčná linie SH-SY5Y. Oba melaniny byly strukturně detailně charakterizovány. Po inkubaci SH-SY5Y buněk s bakteriálním a syntetickým melaninem (0–200 μg/ml) byla studována životaschopnost buněk, hladiny glutathionu, buněčná morfologie a buněčná respirace. Strukturální analýza ukázala, že bakteriální melanin je hydrofilnější, díky přítomnosti většího počtu –OH skupin. Po inkubaci buněk s testovanými melaniny jsme zjistili, že syntetický melanin v podobné dávce způsoboval vždy větší poškození buněk ve srovnání s bakteriálním melaninem. Navíc byl pozorován závažnější toxický účinek syntetického melaninu na mitochondrie. Obecně jsme dospěli k závěru, že hydrofilnější bakteriální melanin indukoval nižší toxicitu u neuroblastomových buněk, než melanin syntetický. Naše poznatky mohou být využitelné zejména při studiu neurotoxicity, neuromodulace a neuroprotekce