Characterisation of cold atmospheric plasma afterglow for decontamination

The exploration missions of outer space and the associated search for extra-terrestrial lifeforms require to fulfil the international planetary protection policies of COSPAR. Today, dry heat microbial reduction (DHMR) and vapor phase bioburden reduction using hydrogen peroxide (VHP) are validated sterilisation methods for space missions. However, the fact that these methods could negatively influence sensitive materials increases the demand of alternative decontamination methods for space research. Cold atmospheric plasma (CAP) provides one of the most promising low-temperature decontamination methods and comprises various benefits such as low cost, simple design and comfortable usage. In the presented work, a newly developed plasma afterglow circulation apparatus (PACA) based on the surface micro-discharge (SMD) technology is investigated. To understand the important chemical reaction processes and to evaluate the presented PACA as a useful alternative decontamination method for planetary protection, this thesis combines interdisciplinary research fields of physics, biology and chemistry. In particular, the chemical reaction processes, the microbial inactivation and the material compatibility of the plasma treatment are investigated

Characterisation of cold atmospheric plasma afterglow for decontamination

The exploration missions of outer space and the associated search for extra-terrestrial lifeforms require to fulfil the international planetary protection policies of COSPAR. Today, dry heat microbial reduction (DHMR) and vapor phase bioburden reduction using hydrogen peroxide (VHP) are validated sterilisation methods for space missions. However, the fact that these methods could negatively influence sensitive materials increases the demand of alternative decontamination methods for space research. Cold atmospheric plasma (CAP) provides one of the most promising low-temperature decontamination methods and comprises various benefits such as low cost, simple design and comfortable usage. In the presented work, a newly developed plasma afterglow circulation apparatus (PACA) based on the surface micro-discharge (SMD) technology is investigated. To understand the important chemical reaction processes and to evaluate the presented PACA as a useful alternative decontamination method for planetary protection, this thesis combines interdisciplinary research fields of physics, biology and chemistry. In particular, the chemical reaction processes, the microbial inactivation and the material compatibility of the plasma treatment are investigated

Influence of repeated pyrethroid applications on the sensitivity of pyrethroid-resistant pollen beetles (Meligethes aeneus F.) and their offspring

In der Vergangenheit erfolgte die Kontrolle von Rapsglanzkäfern hauptsächlich durch die Anwendung von synthetischen Pyrethroiden. Durch die häufige und einseitige Nutzung dieser Insektizidgruppe entstand ein hoher Selektionsdruck, der die Ausbildung einer Resistenz zur Folge hatte, die sich über ganz Deutschland und viele europäische Länder ausgebreitet hat. Das Ausweichen auf Insektizide mit anderen Wirkmechanismen ist nur bedingt möglich, da nur wenige solcher Produkte verfügbar sind.Um die Sensitivität von adulten Rapsglanzkäfern und deren Nachkommen gegenüber lambda-cyhalothrin zu untersuchen, wurde 2012 ein Feldversuch mit zwei unbehandelten Kontrollparzellen und zwei fünfmal mit lambda-cyhalothrin behandelten Parzellen durchgeführt. Um die Sensitivität der Käfer, die Dosierungen von 0.015 bis 0.375 μg lambda-cyhalothrin cm–2 ausgesetzt waren, zu überprüfen, wurde der Adult-Vial-Test genutzt. Alle Proben wurden als resistent oder hoch resistent eingestuft. Über den Versuchszeitraum wurden Schwankungen in der Sensitivität festgestellt. Es traten nur geringe Sensitivitätsunterschiede zwischen Käfern aus behandelten und unbehandelten Parzellen auf. Dennoch waren die Sen­sitivitätsschwankungen zwischen aufeinanderfolgenden Sammelterminen in den behandelten Parzellen geringer.Die mittels Photoeklektoren gefangenen Jungkäfer wiesen ein ähnliches Resistenzniveau wie die Elterngeneration auf. Im Vergleich zur Sensitivität der überwinterten Generation zeigten die Jungkäfer geringere LD50-Werte. Die Anzahl der zur Verpuppung in den Boden abwandernden Larven war in den mit lambda-cyhalothrin behandelten Parzellen 18% geringer als in den unbehandelten Par­zellen. Ähnliche Unterschiede wurden bei der Anzahl der schlüpfenden Jungkäfer festgestellt. Dies deutet auf einen unerheblichen Effekt der Pyrethroid-Applikationen auf die Populationsdynamik von resistenten Rapsglanzkäfern hin. DOI: 10.5073/JfK.2014.03.01, https://doi.org/10.5073/JfK.2014.03.01In the past, control of pollen beetles was mainly based on the application of synthetic pyrethroids. The frequent and indiscriminate use of this insecticide class resulted in a high selection pressure, ensuing in the formation of resistance, which has spread over the whole area of Germany and many European countries. Replacement by insecticides with other modes of action is limited as few alternative products are available.To analyze the relative sensitivity of adult pollen beetles and their offspring to lambda-cyhalothrin, a field trial was conducted in 2012 which included two control plots without insecticide applications and two plots sprayed five times with lambda-cyhalothrin. The Adult-Vial-Test was used to analyze the sensitivity of the beetles when exposed to dosages from 0.015 to 0.375 μg lambda-cyhalothrin cm–2. All samples were classified as resistant or highly resistant. Over the trial period fluctuations of the sensitivity were noticed. Only small differences occurred between the sensitivity of beetles from treated and untreated plots. However, the fluctuation of the sensitivity between successive sampling dates was smaller in treated plots.New generation pollen beetles were caught by using photoeclectors and the resistance classified relative to their parent generation. In comparison to the sensitivity of the overwintered generation, new generation beetles showed lower LD50-values. The number of larvae migrating to soil for pupation in plots treated with lambda-cyhalothrin, was 18% lower than in untreated plots. Similar differences occurred with the number of emerging adults of the new generation. This indicates a negligible effect of pyrethroid applications on population dynamics of resistant pollen beetles. DOI: 10.5073/JfK.2014.03.01, https://doi.org/10.5073/JfK.2014.03.0

Growth and development of Artemisia annua l. on different soil types

Artemisia annua, a neophyte from the temperate zone in Asia, became established within 30 years on the banks of the middle course of the river Elbe. One reason for the fast expansion and the success of this plant is its settlement ability on different soil types, which was tested with field and greenhouse experiments. A. annua displays a remarkable phenotypic plasticity, comparable to successful weeds such as e. g. Chenopodium album. Available nutrients are readily utilized for an increase of biomass and diaspore production. The relatively low demands on its environment paired with the ability to exploit resources successfully help A. annua to colonize different sites of the river banks

Intravascular tissue factor initiates coagulation via circulating microvesicles and platelets

Although tissue factor (TF), the principial initiator of physiological coagulation and pathological thrombosis, has recently been proposed to be present in human blood, the functional significance and location of the intravascular TF is unknown. In the plasma portion of blood, we found TF to be mainly associated with circulating microvesicles. By cell sorting with the specific marker CD42b, platelet-derived microvesicles were identified as a major location of the plasma TF. This was confirmed by the presence of full-length TF in microvesicles acutely shedded from the activated platelets. TF was observed to be stored in the α-granules and the open canalicular system of resting platelets and to be exposed on the cell surface after platelet activation. Functional competence of the blood-based TF was enabled when the microvesicles and platelets adhered to neutrophils, as mediated by P-selectin and neutrophil counterreceptor (PSGL-1, CD18 integrins) interactions. Moreover, neutrophil-secreted oxygen radical species supported the intravascular TF activity. The pools of platelet and microvesicle TF contributed additively and to a comparable extent to the overall blood TF activity, indicating a substantial participation of the microvesicle TF. Our results introduce a new concept of TF-mediated coagulation crucially dependent on TF associated with microvesicles and activated platelets, which principally enables the entire coagulation system to proceed on a restricted cell surface

Impact of Selected Small-Molecule Kinase Inhibitors on Lipid Membranes

Small-molecule protein kinase inhibitors are used for the treatment of various diseases. Although their effect(s) on the respective kinase are generally quite well understood, surprisingly, their interaction with membranes is only barely investigated; even though these drugs necessarily come into contact with the plasma and intracellular membranes. Using biophysical methods such as NMR, ESR, and fluorescence spectroscopy in combination with lipid vesicles, we studied the membrane interaction of the kinase inhibitors sunitinib, erlotinib, idelalisib, and lenvatinib; these drugs are characterized by medium log p values, a parameter reflecting the overall hydrophobicity of the molecules, which is one important parameter to predict the interaction with lipid membranes. While all four molecules tend to embed in a similar region of the lipid membrane, their presence has different impacts on membrane structure and dynamics. Most notably, sunitinib, exhibiting the lowest log p value of the four inhibitors, effectively influences membrane integrity, while the others do not. This shows that the estimation of the effect of drug molecules on lipid membranes can be rather complex. In this context, experimental studies on lipid membranes are necessary to (i) identify drugs that may disturb membranes and (ii) characterize drug–membrane interactions on a molecular level. Such knowledge is important for understanding the efficacy and potential side effects of respective drugs.Peer Reviewe

Membrane Interaction of Ibuprofen with Cholesterol-Containing Lipid Membranes

Deciphering the membrane interaction of drug molecules is important for improving drug delivery, cellular uptake, and the understanding of side effects of a given drug molecule. For the anti-inflammatory drug ibuprofen, several studies reported contradictory results regarding the impact of ibuprofen on cholesterol-containing lipid membranes. Here, we investigated membrane localization and orientation as well as the influence of ibuprofen on membrane properties in POPC/cholesterol bilayers using solid-state NMR spectroscopy and other biophysical assays. The presence of ibuprofen disturbs the molecular order of phospholipids as shown by alterations of the 2H and 31P-NMR spectra of the lipids, but does not lead to an increased membrane permeability or changes of the phase state of the bilayer. 1H MAS NOESY NMR results demonstrate that ibuprofen adopts a mean position in the upper chain/glycerol region of the POPC membrane, oriented with its polar carbonyl group towards the aqueous phase. This membrane position is only marginally altered in the presence of cholesterol. A previously reported result that ibuprofen is expelled from the membrane interface in cholesterol-containing DMPC bilayers could not be confirmed.Deutsche ForschungsgemeinschaftPeer Reviewe