Differences in the ultrastructure of two selected taxa of phytoplankton in a thermally stratified Lake Holzmaar (Germany)

This paper presents the results of ultrastructural studies and ecological aspects of some phytoplankton species belongingto the groups of cyanobacteria (Planktothrix rubescens, Synechocystis aquatilis) and green algae (Desmodesmus grahneisii). Specimens were collected during summertime from the mesotrophic and stratified Lake Holzmaar (Western Germany) as planktonic from the pelagic zone. The highest cyanobacterium P. rubescens concentration was detected in the metalimnion where the alkaline pH, low phosphorus and high nitrogen contents were recorded. It was characterized by straight filaments up to 1000 um long and 5.4-8 um wide and numerous aerotopes in cells. The accompanying algae were identified by ultrastructuralanalysis and photographic documentation was provided. In the case of D. grahneisii, chloroplast was concentrated in the parietal part of cell with one large, oval pyrenoid and, in addition, the granular and spiny cell wall clearly showed important taxonomical criteria for Desmodesmus genera. This is in contrast with cyanobacterium S. aquatilis where the presence of a homogeneous content with visible chromatoplasma was mostly distributed through the cell. This algal association was stable in the epilimnion characterized by the presence of high temperature, pH values, nitrate nitrogen and oxygen concentrations

Study on a three-step rapid assembly of zolpidem and its fluorinated analogues employing microwave-assisted chemistry

We developed an efficient microwave-assisted three-step synthesis of zolpidem and its fluorinated analogues 1–3. The procedure relays on the utilization of easily accessible and inexpensive starting materials. Our protocol shows superior performance in terms of yield and purity of products, compared to conventional heating systems. Notably, the total time needed for reaction accomplishment is significantly lower comparing to oil bath heating systems. Finally, we have performed a detailed study on the preparation of zolpidem tartrate salt I, and we assessed its particle-sizes using a polarizing microscope. Our goal was to select the appropriate method that generates the acceptable particle-size, since the solid-size directly influences solubility in biological fluids and further bioavailability. We believe that the disclosed procedure will help to produce a lab-scale quantity of zolpidem and its fluorinated derivatives 1–3, as well as zolpidem tartrate salt I, with suitable fine-particle size for further biological experimentation

Vom Germanistikstudium zum Arbeitsmarkt – Rückblick und aktueller Bestand

Die berufliche Positionierung der angehenden Germanist(inn)en auf dem gegenwärtigen Arbeitsmarkt ist mittlerweile Gegenstand zahlreicher Diskussionspanels, Tagungen und Beiträge. Im Mittelpunkt der Debatte steht zum einen die Frage nach aktueller gesellschaftlicher Relevanz der Germanistik und nach deren möglicher inhaltlicher Ausrichtung auf andere als traditionell bewährte Fächer (Literatur oder Sprachwissenschaft), z. B. Fachkommunikation, Fachsprachenunterricht, Fachdolmetschen bzw. -übersetzen. Zum anderen kommt es dabei auf die Frage nach Kompetenzorientierung der Germanistikabsolvent(inn)en an. Gemeint sind hier Sprach- und Fachkompetenzen sowie die gegenwärtig gefragten Schlüsselkompetenzen, wie etwa die interkulturelle oder die rhetorische. Derartigen Fragestellungen widmet sich auch der vorliegende Beitrag und bietet im Rückblick auf einige exemplarisch gewählte Publikationen eine systematische Zusammenfassung der in dem vorliegenden Kontext wichtigsten Problemstellungen

Morphological and ultrastructural studies on Ulva flexuosa subsp. pilifera (Chlorophyta) from Poland

Ulva flexuosa subsp. pilifera (Kütz.) M. J. Wynne 2005 (= Enteromorpha pilifera Kützing 1845) was previously found in Argentina, the Czech Republic, Germany, Hungary, Romania, Slovakia and Sweden, recently also in Poland. The genus Ulva was first time described as Enteromorpha. Interestingly, Enteromorpha is used nowadays as a synonym for Ulva, a development which is based on molecular data. The morphologies of both young and mature specimens were studied, and most life cycle stages could be observed. Further, the formation of calcium carbonate crystals on the surface of Ulva thalli seems to influence the arrangement of the cells. A detailed ultrastructural (TEM) analysis of cell walls is presented. The TEM reveals in great details highly complex, irregular structures with stratification lines.The project was supported by funding from the Polish Ministry of Science, grant No. NN 304 013 437 and partially funded by the project GDWB-07/ 2011.822157163Acta Societatis Botanicorum Polonia

Ulva flexuosa subsp. pilifera (Chlorophyta, Ulvophyceae) from the Wielkopolska region (West Poland): a new observation of the ultrastructure of vegetative cells

Ulva flexuosa subsp. pilifera previously known from northern Poland, from the channel near Szczecin and ponds near Łódź, has recently been found in the Malta Reservoir in the Wielkopolska (West Poland) region. Specimens collected in the Wielkopolska region were examined in detail, also under a transmission electron microscope (TEM). The morphometric analysis of Ulva thalli (both young and mature specimens) was performed in order to study the differences in the ultrastructure of vegetative cells. Rectangular cells in young thalli measured from 32.21 - 55.81 μm to 20.24 – 35.12 μm, and they formed clear longitudinal rows, while cells in the mature specimens ranged from 25.09 – 47.66 μm to 18.90 – 31.56 μm. This study indicates that vegetative cells of the mature thalli show tendency towards distortions of both the longitudinal and transverse cells arrangement. This distortion is determined by the development of possible carbonate calcium crystals on the thalli surface. The ultrastructural analysis (TEM) confirmed that the structure and placement of thylakoids is genus/species specific.This work was supported by the grant NN 304 013 437.422209215Oceanological and Hydrobilogical Studie