Influence of vitamin B12 and light on the formation of chlorosomes in green- and brown-colored Chlorobium species

The specific Bchl a and c content of the vitamin B12-dependent Chlorobium limicola strain 1230 decreased strongly under vitamin B12 limitation. In comparison to a regularly grown culture (20 g vitamin B12/l) the specific Bchl c content of a B12-limited culture was reduced to 20% and the specific Bchl a content to 42%. By ultrathin sections it could be clearly demonstrated that B12-deficient cells contained no chlorosomes. After the addition of vitamin B12 to a deficient culture, chlorosomes were formed and the Bchl a and c content increased again to the level of regularly grown cells. The brown-colored Chlorobium phaeobacteroides strain 2430 (type strain) and the extremely low-light-adapted strain MN1 were compared with respect to the influence of light on the formation of chlorosomes and the Bchl e and carotenoid content. By ultrathin sections it could be demonstrated that strain MN1 produced two-fold larger chlorosomes. Chlorosome dimensions of strain MN1 decreased with increasing light intensities. The number of chlorosomes per cell in both strains did not change with different light intensities. Strain MN1 formed twice as much Bchl e as the type strain when grown at 30 or below 1 mol · m-2 · s-1. Under comparable light conditions strain MN1 formed 14–57% more carotenoids than the type strain. Low light intensities aaused the carotenoid content to increase by 25% in strain 2430 in comparison to high light intensity

Investigation of Frizzled-5 during embryonic neural development in mouse

Journal ArticleCellular and tissue--tissue interactions regulate development of the central nervous system (CNS) and a paramount question is what is the nature of the signals involved in these interactions. The vertebrate eye represents an excellent and challenging CNS model because it contains multiple cell and tissue types that must coordinate their development to form a functional unit. Eye development becomes apparent when the ventral diencephalic neuroepithelium evaginates to form the optic vesicles. The neural retina and retinal pigment epithelium become patterned in the distal and proximal domains of the optic vesicle, respectively. Adjacent extraocular tissues such as the surrounding mesenchyme, the overlying surface ectoderm and the ventral diencephalon regulate these patterning events. Interaction between the distal optic vesicle and surface (lens) ectoderm leads to invagination, formation of the optic cup, and subsequent development of the lens. Several genes have been shown to control optic cup morphogenesis and differentiation of ocular tissues

Extraocular ectoderm triggers dorsal retinal fate during optic vesicle evagination in zebrafish

pre-printDorsal retinal fate is established early in eye development, via expression of spatially restricted dorsal‐specific transcription factors in the optic vesicle; yet the events leading to initiation of dorsal fate are not clear. We hypothesized that induction of dorsal fate would require an extraocular signal arising from a neighboring tissue to pattern the prospective dorsal retina, however no such signal has been identified. We used the zebrafish embryo to determine the source, timing, and identity of the dorsal retina‐inducing signal. Extensive cell movements occur during zebrafish optic vesicle morphogenesis, however the location of prospective dorsal cells within the early optic vesicle and their spatial relationship to early dorsal markers is currently unknown. Our mRNA expression and fate mapping analyses demonstrate that the dorsolateral optic vesicle is the earliest region to express dorsal specific markers, and cells from this domain contribute to the dorsal retinal pole at 24 hpf. We show that three bmp genes marking dorsal retina at 25 hpf are also expressed extraocularly before retinal patterning begins. We identified gdf6a as a dorsal initiation signal acting from the extraocular non‐neural ectoderm during optic vesicle evagination. We find that bmp2b is involved in dorsal retina initiation, acting upstream of gdf6a. Together, this work has identified the nature and source of extraocular signals required to pattern the dorsal retina

Isolation of equine endothelial cells and life cell angiogenesis assay

Arterial or venous thromboses are frequent clinical complications with the risk of fatal progression. Recent studies suggest the disruption of angiogenesis in the course of thrombus resolution as the underlying pathomechanism. Very similar to the situation in human patients, equine vessels have been described to be particularly susceptible to thrombosis. In contrast to humans, equine donors are readily available to obtain organs and tissues for isolation of endothelial cells. Objective of this study was to isolate equine endothelial cells and develop an angiogenesis assay from primary cultures. Macrovascular endothelial cells were obtained from jugular veins and carotid arteries of nine horses, one of which suffered from inflammatory processes. After enzymatic isolation, the cells were incubated in different selective primary media. Phenotypic identification of endothelial cells was accomplished by morphology and positive staining to von Willebrand factor. The reliable, inexpensive, and standardized combination of methods presented here resulted in pure endothelial cultures for angiogenesis assays that can be used in any cell culture laboratory. Inverted phase microscopy and life cell imaging was used to characterize the stages of the angiogenic cascade of the endothelial cells. Life cell imaging gave new insights into the in vitro formation of capillary like structures including exocytosis of microparticles from endothelial cells before integration into the three-dimensional structure. We hypothesize that a specific population of endothelial cells showing a highly active migration pattern in life cell imaging might play a role in the resolution of thrombosis

Multiple time-scale approach for a system of Brownian particles in a non-uniform temperature field

8 pages, 2 figures.-- PACS numbers: 05.45.-a, 05.10.Gg.-- arXiv pre-print: http://arxiv.org/abs/cond-mat/0610069.-- Final full-text version of the paper available at: http://dx.doi.org/10.1103/PhysRevE.75.021101.The Smoluchowski equation for a system of interacting Brownian particles in a temperature gradient is derived from the Kramers equation by means of a multiple time-scale method. The interparticle interactions are assumed to be represented by a mean-field description. We present numerical results that compare well with the theoretical prediction together with an extensive discussion on the prescription of the Langevin equation in overdamped systems.C.L. acknowledges financial support from MEC (Spain) and FEDER through project CONOCE2 (FIS2004-00953) and from the bilateral project Spain-Italy HI2004-0144. He also acknowledges a Ramón y Cajal research fellow of the Spanish MEC. U.M.B.M. acknowledges a grant COFIN-MIUR 2005, 2005027808

Learning from students\u27 statements?! - Towards a professional feedback culture at schools

Lehrkräfte sind aufgefordert, die Qualität ihres Unterrichts mithilfe von Schülerrückmeldungen zu überprüfen. In diesem Beitrag wird diskutiert, was unter einer "professionellen Feedbackkultur" in Schulen im Hinblick auf die Verwendung des Schülerfeedbacks zur Messung von Unterrichtsqualität zu verstehen ist und auf welche Verwendungsweisen angesichts des empirischen Forschungsstands zur Validität von Schülerratings zur Unterrichtsqualität möglicherweise auch besser zu verzichten wäre. (DIPF/Orig.)Teachers are encouraged to check the quality of their teaching by using student feedback. This paper discusses what a "professional feedback culture" in schools in the context of measuring teaching quality means. The second question is, whether some uses of student feedback are not useful in light of the empirical research literature on validity of student ratings of teaching quality. (DIPF/Orig.

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Die Ausstellung „Osmanen in Hamburg – eine Beziehungsgeschichte zur Zeit des Ersten Weltkrieges“, die vom 6. November 2014 bis zum 4. Januar 2015 in der Staats- und Universitätsbibliothek Carl von Ossietzky gezeigt wurde, widmete sich anlässlich des 100. Jahrestages der „Urkatastrophe“ den deutsch-osmanischen Beziehungen aus Hamburger Sicht und nahm vor allem die Zeit zwischen 1914 und 1918 in den Blick. Die erstmals gezeigten Archivmaterialien veranschaulichen dabei nicht nur die wirtschaftlichen, diplomatischen und kulturellen Kontakte. Sie vermitteln vor allem einen Eindruck von der Präsenz und vom Leben der ethnisch wie religiös heterogenen Gruppe der Osmanen (u. a. Armenier, Griechen, sephardische Juden, muslimische Türken) in Hamburg, deren Spuren sich bis ins 19. Jahrhundert zurückverfolgen lassen. Der vorliegende Katalog möchte aber nicht nur die in acht Sektionen unterteilte Ausstellung dokumentieren. Er liefert mit zusätzlichen acht Beiträgen einen weiterführenden Einblick in die komplexe und ambivalente osmanisch-deutsche bzw. hamburgisch-osmanische Beziehungsgeschichte. In drei Kapiteln werden neben den transkulturellen Begegnungen wie Kulturdifferenzen der Zeit von etwa 1850 bis 1909, die kolonialen Ambitionen und orientalistischen Embleme des Deutschen Reiches, aber auch die Rolle deutscher Frauen im Osmanischen Reich zwischen 1914 und 1918 beleuchtet.The exhibition "Osmanen in Hamburg - a relationship history during the First World War" which was shown in the Hambrug State and University Library from November 6th, 2014 to January 4th, 2015, devoted itself to the 100th anniversary of the "Urkatastrophe" (the Great War) to he German-Ottoman relations from the perspective of Hamburg, and focused on the years between 1914 and 1918. The archival objects were presented for the first time and are documented in this publication. They illustrate not only economic, diplomatic and cultural contacts., but also give an impression of the presence and the life of the ethnically and religiously heterogeneous group of the Ottomans (e.g. Armenians, Greeks, Sephardic Jews, Muslim Turks) in Hamburg who can be traced back to the 19th century. This catalog, however, does not only want to document the exhibition which was divided into eight sections. With an additional eight contributions, it provides a deeper insight into the complex and ambivalent Ottoman-German and/ or Hamburg-Ottoman relations. In addition to transcultural encounters such as cultural differences between the time of 1850 and 1909 the colonial ambitions and oriental emblems of the German Reich, as well as the role of German women in the Ottoman Empire between 1914 and 1918, are illuminated in three chapters

[Insulin pump therapy and continuous glucose monitoring].

This Guideline represents the recommendations of the Austrian Diabetes Association (ÖDG) on the use of diabetes technology (insulin pump therapy; continuous glucose monitoring, CGM; hybrid closed-loop systems, HCL; diabetes apps) and access to these technological innovations for people with diabetes mellitus based on current scientific evidence

Planet Populations as a Function of Stellar Properties

Exoplanets around different types of stars provide a window into the diverse environments in which planets form. This chapter describes the observed relations between exoplanet populations and stellar properties and how they connect to planet formation in protoplanetary disks. Giant planets occur more frequently around more metal-rich and more massive stars. These findings support the core accretion theory of planet formation, in which the cores of giant planets form more rapidly in more metal-rich and more massive protoplanetary disks. Smaller planets, those with sizes roughly between Earth and Neptune, exhibit different scaling relations with stellar properties. These planets are found around stars with a wide range of metallicities and occur more frequently around lower mass stars. This indicates that planet formation takes place in a wide range of environments, yet it is not clear why planets form more efficiently around low mass stars. Going forward, exoplanet surveys targeting M dwarfs will characterize the exoplanet population around the lowest mass stars. In combination with ongoing stellar characterization, this will help us understand the formation of planets in a large range of environments.Comment: Accepted for Publication in the Handbook of Exoplanet

Quantitative High-Resolution Genomic Analysis of Single Cancer Cells

During cancer progression, specific genomic aberrations arise that can determine the scope of the disease and can be used as predictive or prognostic markers. The detection of specific gene amplifications or deletions in single blood-borne or disseminated tumour cells that may give rise to the development of metastases is of great clinical interest but technically challenging. In this study, we present a method for quantitative high-resolution genomic analysis of single cells. Cells were isolated under permanent microscopic control followed by high-fidelity whole genome amplification and subsequent analyses by fine tiling array-CGH and qPCR. The assay was applied to single breast cancer cells to analyze the chromosomal region centred by the therapeutical relevant EGFR gene. This method allows precise quantitative analysis of copy number variations in single cell diagnostics