Die Lehre aus Sicht der Lernenden: Lehrlinge als neue Anspruchsgruppe im Qualitätsdiskurs beruflicher Lernprozesse

Im österreichischen Bildungswesen sind durchgängig Qualitätssicherungsverfahren und -strukturen etabliert worden, die Ausnahme bestand in der betriebsbasierten Berufsausbildung (abgesehen von der vor externen Prüfenden abgelegten Lehrabschlussprüfung). Nun liefert der "Erste Österreichische Lehrlingsmonitor" repräsentative Daten zur Weiterentwicklung des Lehrausbildungssystems: Insgesamt nehmen Lehrlinge am Ende der Ausbildung diese mehrheitlich positiv wahr, kritische Bereiche deuten auf eine Schwäche des Gesamtsystems hin oder führen in der betrieblichen Praxis wiederkehrend zu Problemen

Assay development for and evaluation of sphingomyelinase D and associated activities in venoms from Loxosceles reclusa and Kukulcania hibernalis and in isolated soil bacteria

Since a sphingomyelinase D (SMase D) enzyme is presumably the major agent in the necrosis and toxicity of the brown recluse spider venom by cleaving sphingomyelin (SM) to ceramide 1,3-cyclic phosphate (Cer(1,3)P), a rigorous but simple assay would aid in detecting the presence of this sphingomyelinase activity. Several Sicariidae spiders, such as the brown recluse spider Loxosceles reclusa, and some pathogenic bacteria contain phospholipase D (PLase D) enzymes that act on phospholipid substrates. PLases D that cleave SM to release the headgroup choline are also called SMases D. Although the lipid product of the L. reclusa SMase D was initially thought to be ceramide 1-phosphate (Cer1P), a transphosphatidylation mechanism by L. reclusa SMase D has been shown to produce Cer(1,3)P. For this thesis, fluorescent nitrobenzoxadiazole (NBD) analogs of products that are known to be made by various types of SMases (i.e., ceramide, Cer1P and Cer(1,3)P) were synthesized and an elution solvent system was identified that fully resolves these compounds as well as the substrate NBD-SM using silica gel thin-layer chromatography plates. When venom from L. reclusa was assayed, the product was the expected NBD-labeled Cer(1,3)P. Venom from Kukulcania hibernalis, a spider that has been suggested to have SMase D but whose products have not yet been determined, was assayed as well and NBD-Cer(1,3)P was found to be produced. To explore additional biomedically relevant applications of these methodologies, such as to discover bacterial enzymes that can degrade sphingolipids, we attempted to isolate bacteria from the soil with enzymatic activity to degrade SM and/or cyclic Cer(1,3)P. Single isolates of soil microorganisms were selected based on their ability to grow on the restrictive carbon sources SM or Cer(1,3)P and then examined for their cleavage of NBD-SM and/or NBD-Cer(1,3)P. Of four candidate isolates, genome sequencing of two isolates was taxonomically assigned to Klebsiella variicola, a gram-negative bacterium and opportunistic human pathogen. Unfortunately, in the timeframe of this thesis, the conditions to assay the degradatory enzymes were not found. In summary, this work has developed a facile assay for SMase D, characterized for the first time Cer(1,3)P as a breakdown product of the action of K. hibernalis venom on SM, and expanded the methodologies that are available for analysis of activities that produce and degrade Cer(1,3)P.M.S

Maskless lithography for versatile and low cost fabrication of polymer based micro optical structures

For applications in optical communication, sensing or information projection in automotive lighting, polymer based optical devices are of keen interest. Optical structures such as waveguides and gratings are basic blocks for these devices. We report on a simple, versatile, and yet low-cost fabrication method suited for both binary and multilevel diffractive microstructures as well as multimode optical waveguides in polymers. The fabrication of the diffractive structures, i.e. gratings, with two and multiple levels, is achieved by using a maskless optical lithography system employing a spatial light modulator. With the same system, waveguide cladding structures are realized by stitching of multiple single exposure patterns. For replication of these structures on polymer, e.g. polymethyl methacrylate (PMMA), a lab-made hot embossing machine is used. We then employ UV curable material and doctor blading to realize the waveguide cores. The created diffractive and waveguide structures are characterized in terms of diffraction efficiency and optical propagation loss, respectively, showing good optical quality and performance. With our fabrication system we have demonstrated a diffraction efficiency of 71% for multilevel grating structure and a propagation loss for stitched waveguides of 2.07 dB/cm at a wavelength of 638 nm. These basic elements will be employed to realize entire optical measurement systems for applications in sensing and integrated photonics in the next step

Development of an Assay for Sphingomyelinase D Products in Venom from Loxosceles reclusa and Other Spiders

The venoms of Loxosceles reclusa, the brown recluse spider, and some other Loxosceles species cause dermonecrotic lesions—a dying of the flesh—and in severe cases, systemic injury and death. Since this type of injury results from a bite, diagnosis can be cryptic unless the culprit spider is available to be identified by an expert. The distribution of Loxosceles reclusa is also not well known, which further complicates diagnosis. These spiders are of additional interest because one of the agents in the venom is a sphingomyelinase D (SMase D) that cleaves the head group of sphingomyelin (SM) and causes intramolecular transphosphatidylation to produce ceramide 1,3-cyclic phosphate (Cer(1,3)P), a lipid that is not known to be present in humans otherwise. Therefore, a simple assay to analyze the presence of SMase D, by either activity assays or detection of its product Cer(1,3)P, could aid in identification of spider bites and possibly facilitate development of a treatment. A key reagent for such studies is Cer(1,3)P which is currently not commercially available, so we have developed a method for its synthesis and identified conditions for distinguishing Cer(1,3)P from the substrate SM and alternative hydrolysis products (ceramide-1-phosphate and ceramide) by thin-layer chromatography. The availability of this chemical and its synthesis procedure enables an assay of SMase D for better characterization of this important component of brown recluse spider venom (and possibly other organisms). Moreover, the assay could be used to search for enzymes that hydrolyze Cer(1,3)P, and such enzymes might prove useful in the development of a treatment for these wounds.Undergraduat

Quantifying Nonspecific TEM -Lactamase (blaTEM) Genes in a Wastewater Stream

To control the antibiotic resistance epidemic, it is necessary to understand the distribution of genetic material encoding antibiotic resistance in the environment and how anthropogenic inputs, such as wastewater, affect this distribution. Approximately two-thirds of antibiotics administered to humans are β-lactams, for which the predominant bacterial resistance mechanism is hydrolysis by β-lactamases. Of the β-lactamases, the TEM family is of overriding significance with regard to diversity, prevalence, and distribution. This paper describes the design of DNA probes universal for all known TEM β-lactamase genes and the application of a quantitative PCR assay (also known as Taqman) to quantify these genes in environmental samples. The primer set was used to study whether sewage, both treated and untreated, contributes to the spread of these genes in receiving waters. It was found that while modern sewage treatment technologies reduce the concentrations of these antibiotic resistance genes, the ratio of blaTEM genes to 16S rRNA genes increases with treatment, suggesting that bacteria harboring blaTEM are more likely to survive the treatment process. Thus, β-lactamase genes are being introduced into the environment in significantly higher concentrations than occur naturally, creating reservoirs of increased resistance potential.Organismic and Evolutionary Biolog

Kompetenzanerkennung und Validierungspraxis in der Erwachsenen- und Weiterbildung

Lehrende in der Erwachsenen- und Weiterbildung verfügen über viel praktische Lern- und Berufserfahrungen, die sie jedoch nicht immer sichtbar nachweisen können. Für ihre Professionalisierung ist es wichtig, die eigenen Kompetenzen in einem Validierungs- und Anerkennungsverfahren prüfen zu lassen. Doch wie kann die Qualität solcher Prüfverfahren gesichert werden? Die Autorinnen und Autoren präsentieren die Ergebnisse einer wissenschaftlichen Begleitstudie an der Weiterbildungsakademie Österreich (wba) und reflektieren den kausalen Zusammenhang von Professionalisierung und Kompetenzvalidierung. Dabei zeigt sich ein Handlungsfeld von großer Komplexität, in dem die Expertise und das Zusammenspiel der Beteiligten auf unterschiedlichen Verfahrensebenen über die Qualität entscheidet

Antibiotic Resistance Genes in the Bacteriophage DNA Fraction of Environmental Samples

Antibiotic resistance is an increasing global problem resulting from the pressure of antibiotic usage, greater mobility of the population, and industrialization. Many antibiotic resistance genes are believed to have originated in microorganisms in the environment, and to have been transferred to other bacteria through mobile genetic elements. Among others, β-lactam antibiotics show clinical efficacy and low toxicity, and they are thus widely used as antimicrobials. Resistance to β-lactam antibiotics is conferred by β-lactamase genes and penicillin-binding proteins, which are chromosomal- or plasmid-encoded, although there is little information available on the contribution of other mobile genetic elements, such as phages. This study is focused on three genes that confer resistance to β-lactam antibiotics, namely two β-lactamase genes (blaTEM and blaCTX-M9) and one encoding a penicillin-binding protein (mecA) in bacteriophage DNA isolated from environmental water samples. The three genes were quantified in the DNA isolated from bacteriophages collected from 30 urban sewage and river water samples, using quantitative PCR amplification. All three genes were detected in the DNA of phages from all the samples tested, in some cases reaching 104 gene copies (GC) of blaTEM or 102 GC of blaCTX-M and mecA. These values are consistent with the amount of fecal pollution in the sample, except for mecA, which showed a higher number of copies in river water samples than in urban sewage. The bla genes from phage DNA were transferred by electroporation to sensitive host bacteria, which became resistant to ampicillin. blaTEM and blaCTX were detected in the DNA of the resistant clones after transfection. This study indicates that phages are reservoirs of resistance genes in the environment

Antibiotic resistance genes in an urban river as impacted by bacterial community and physicochemical parameters

Antibiotic resistance genes (ARGs) in urban rivers are a serious public health concern in regions with poorly planned, rapid development. To gain insights into the predominant factors affecting the fate of ARGs in a highly polluted urban river in eastern China, a total of 285 ARGs, microbial communities, and 20 physicochemical parameters were analyzed for 17 sites. A total of 258 unique ARGs were detected using high-throughput qPCR, and the absolute abundance of total ARGs was positively correlated with total organic carbon and total dissolved nitrogen concentrations (P < 0.01). ARG abundance and diversity were greatly altered by microbial community structure. Variation partitioning analysis showed that the combined effects of multiple factors contributed to the profile and dissemination of ARGs, and variation of microbial communities was the major factor affecting the distribution of ARGs. The disparate distribution of some bacteria, including Bacteroides from mammalian gastrointestinal flora, Burkholderia from zoonotic infectious diseases, and Zoogloea from wastewater treatment, indicates that the urban river was strongly influenced by point-source pollution. Results imply that microbial community shifts caused by changes in water quality may lead to the spread of ARGs, and point-source pollution in urban rivers requires greater attention to control the transfer of ARGs between environmental bacteria and pathogens

INVESTIGATION OF SOLID-STATE SELF-ASSEMBLY OF ONE- AND MULTI- COMPONENT SUGAR POLYOLEFIN CONJUGATES AND MECHANISMS FOR FRANK-KASPER MESOPHASE TRANSITIONS

The self-assembly of molecules provides the basis of life and has become ubiquitous for the development of nanostructured materials. Nanostructured materials have long reaching impacts for the furtherment of science, as the next revolution in technology requires the ability to fabricate nanostructured materials with sub-10-nm feature sizes. To this end, the work herein, presents on methods and mechanisms of solid-state nanostructured mesophase formation, through the isolation of complex phases and understanding of thermotropic order-order transition pathways. This extends to both solid-state classical and nonclassical phases, including the highly desirable, bicontinuous double gyroid, and uncommon Frank-Kasper (FK) phases resulting from self-assembly of the sugar polyolefin conjugates. The sugar polyolefin conjugates are produced through practical and scalable bulk quantities that demonstrate the dynamic self-assembly on the nanometer-scale, which results from rapid thermally induced order-order phase transitions. Production of different derivatives of the sugar polyolefin conjugates and blended systems, can significantly lower the barriers to access uncommon and complex mesophases through the elucidation of transition mechanisms for FK mesophases. To better understand the basic principles and mechanisms of formation that result in the complex packing motifs of FK phases, single- and multi-component systems were devised. These mechanisms avoid the need for large structural reconfigurations of spheres, and dynamic mass transfer, as previous solid-state thermotropic mechanisms have required. Additionally, a general strategy for design, modulation, and utilization of functionally competent soft matter solid-state FK phases is provided from developments with a two-component system utilizing a small molecule additive. These results demonstrate the sugar polyolefin conjugates as an exceptional class of self-assembling amphiphilic materials, which provide methods for reliably producing Frank-Kasper phases from single- and multi-component systems, in addition to remarkable classical phase behavior