In Vitro Recapitulation of Developmental Transitions in Human Neural Stem Cells.

During nervous system development, early neuroepithelial stem (NES) cells with a highly polarized morphology and responsiveness to regionalizing morphogens give rise to radial glia (RG) cells, which generate region-specific neurons. Recently, stable neural cell populations reminiscent of NES cells have been obtained from pluripotent stem cells and the fetal human hindbrain. Here, we explore whether these cell populations, similar to their in vivo counterparts, can give rise to neural stem (NS) cells with RG-like properties and whether region-specific NS cells can be generated from NES cells with different regional identities. In vivo RG cells are thought to form from NES cells with the onset of neurogenesis. Therefore, we cultured NES cells temporarily in differentiating conditions. Upon reinitiation of growth factor treatment, cells were found to enter a developmental stage reflecting major characteristics of RG-like NS cells. These NES cell-derived NS cells exhibited a very similar morphology and marker expression as primary NS cells generated from human fetal tissue, indicating that conversion of NES cells into NS cells recapitulates the developmental progression of early NES cells into RG cells observed in vivo. Importantly, NS cells generated from NES cells with different regional identities exhibited stable region-specific transcription factor expression and generated neurons appropriate for their positional identity. Stem Cells 2019;37:1429-1440

Entry Into Afferent Lymphatics and Maturation In Situ of Migrating Murine Cutaneous Dendritic Cells

An important property of dendritic cells (DC), which contributes crucially to their strong immunogenic function, is their capacity to migrate from sites of antigen capture to the draining lymphoid organs. Here we studied in detail the migratory pathway and the differentiation of DC during migration in a skin organ culture model and, for comparison, in the conventional contact hypersensitivity system. We report several observations on the capacity of cutaneous DC to migrate in mouse ear skin. (i) Upon application of contact allergens in vivo the density of Langerhans cells in epidermal sheets decreased, as determined by immunostaining for major histocompatibility complex class II, ADPase, F4/80, CD11b, CD32, NLDC-145/DEC-205, and the cytoskeleton protein vimentin. Evaluation was performed by computer assisted morphometry. (ii) Chemically related nonsensitizing or tolerizing compounds left the density of Langerhans cells unchanged. (iii) Immunohistochemical double-staining of dermal sheets from skin organ cultures for major histocompatibility complex class II and CD54 excluded blood vessels as a cutaneous pathway of DC migration. (iv) Electron microscopy of organ cultures revealed dermal accumulations of DC (including Birbeck granule containing Langerhans cells) within typical lymphatic vessels. (v) Populations of migrating DC in organ cultures upregulated markers of maturity (the antigen recognized by monoclonal antibody 2A1, CD86), but retained indicators of immaturity (invariant chain, residual antigen processing function). These data provide additional evidence that during both the induction of contact hypersensitivity and in skin organ culture, Langerhans cells physically leave the epidermis. Both Langerhans cells and dermal DC enter lymphatic vessels. DC mature while they migrate through the skin

Effects of sponge-derived Ageladine A on the photosynthesis of different microalgal species and strains

Fluorescent natural compounds have been identified in several marine hosts of microalgae. Their prevalence, and the energy the host is expending on their synthesis, suggests an important, yet poorly understood ecological role. It has been suggested that some of these natural products may enhance the photosynthesis of microbial symbionts. In this study, the effect of Ageladine A (Ag A), a pH-dependent fluorophore found in sponges of the genus Agelas, on the photosynthesis of nine microalgal species and strains was examined. The data showed that the variety of effects of Ag A additions differed between species, and even strains within a species. While in one strain of Synechococcus sp., the presence of Ag A increased gross photosynthesis under UV light exposure, it decreased in another. And while in the chlorophyte T. chuii overall metabolic activity was greatly reduced under all forms of lighting, photosynthesis in T. lutea was positively affected by the addition of Ag A. The variety of effects of Ag A on photosynthesis observed in this study indicate a complex interaction of Ag A with microalgal cells and suggests that a host may be able to shape its own symbiotic microbiome with self-produced natural products

Reduction Scrotoplasty in 100 kg Scrotums

Scrotal elephantiasis is a rare form of lymphedema of the scrotum. Its pathophysiology is diverse and often not clear, as there are only a few diagnostic tools available. Primary therapy consists, as usual for lymphedema, of conservative measures. However, due to anatomical and physiological findings, conservative therapy options are not always applicable. Although the only possible therapy in severe cases is the surgical resection, there is a lack in the literature regarding a standardized surgical approach. Surgical treatment of massive scrotal elephantiasis was performed in two patients according to a standardized strategy. After computed tomography and planning the operation, the penis and testicles were first exposed. Then, the reduction of the scrotum was performed, by holding the lateral flaps to the contralateral side and setting the cutoff line to the center. The cranial flap was decreased as in a modified abdominoplasty. After surgical treatment following the standardized approach, both patients showed functionally and esthetically positive results. Scrotal elephantiasis has a huge impact on life quality of the affected patients. With the described combination of intense conservative therapy and a standardized surgical procedure, these challenging patients can be helped

Standortspezifische Risikobewertung von Verfahren mechanischer und chemischer Unkrautbekämpfung in Reihenkulturen als Baustein eines nachhaltigen Pflanzenschutzes (Verbundvorhaben)

Die F2F-Strategie der EU zielt auf eine Reduktion des Pestizideinsatzes ab. In der Unkrautkontrolle sollen dazu mechanische Maßnahmen chemische ersetzen. Eine mehrdimensionale Bewertung mechanischer Verfahren auf ökologische, ökonomische und verfahrenstechnische Parameter liegt jedoch bislang nicht vor. Ziel des Projekts war es daher, Kenngrößen mechanischer und chemischer Unkrautbekämpfung in Zuckerrüben als Modellfrucht zu erfassen und zu bewerten. Zu diesem Zweck wurden 3 methodische Ansätze verwendet: (i) Feldversuche wurden in 3 Jahren auf 5-7 Feldern bei Göttingen durchgeführt, um die Auswirkungen des Hackens zur Unkrautkontrolle auf Regenwürmer, Insekten und Spinnen, Wassererosion sowie Unkrautwirkungsgrad und Zuckerrübenertrag zu erfassen; (ii) Das ökotoxikologische Risiko von 5 Unkrautbekämpfungs-verfahren wurde mit SYNOPS-GIS modelliert; (iii) Ressourcenverbrauch, Treibhausgas(THG)-Emissionen und Wirtschaftlichkeit wurden für 11 Unkrautbekämpfungsverfahren mittels Literatur und Webanwendungen berechnet. Die Gesamtbetrachtung der mehrdimensionalen Risiken verschiedener konventioneller und neuer Verfahren zeigt, dass derzeit keine Methode als uneingeschränkt umweltfreundlich bezeichnet werden kann. Die toxikologische Risikobewertung mit SYNOPS-GIS zeigt, dass die Flächenspritzung von praxisüblichen Herbiziden in den meisten Boden-Klima-Räumen (BKR) und Jahren mit einem niedrigen toxikologischen Risiko verbunden. Die Flächenspritzung mit einem Herbizid wie Conviso One ist zwar vorteilhaft für Energieverbrauch, Klimawirkung und Toxizität für Bodenorganismen, weist aber die höchste akute Toxizität auf. Herkömmliche mechanische Verfahren sind toxikologisch zwar unbedenklich, im Vergleich zum ganzflächigen Herbizideinsatz aber mit 100-150 % höheren THG-Emissionen verbunden. Insgesamt hat ein Kleinroboter kombiniert mit Punktspritzung Vorteile. Diese Technik weist einen geringeren Ressourcen- und Energieverbrauch als die konventionelle Flächenspritzung sowie ca. 30 % geringere THG-Emissionen auf und hat ein um 87 % niedrigeres toxikologisches Risiko. Bodenerosion, Abundanz von Regenwürmern, Insekten und Spinnen sowie Zuckerrübenertrag unterschieden sich nicht zwischen den Unkrautbekämpfungs-verfahren

A marine sponge-derived secondary metabolite enhances photosynthesis in Synechococcus bacillaris and putatively in other micro-algae

Marine sponges harbor many symbionts, which constitute a large amount of the sponge's dry weight. The reef sponges Agelas sp. produce a brominated pyrrole alkaloid, Ageladine A, which accumulates in acidic cellular compartments and has previously been used as a pH sensitive, fluorescent dye. Ageladine A may therefore accumulate in the acidic thylakoid lumen of photosynthetic cells. The ecophysiological role of Ageladine A in the sponge biome, however, is still unresolved. Here we show that Ageladine A possibly acts as an additional light harvesting molecule for photosynthesis in Synechococcus bacillaris, a cyanobacteria similar to the sponge's symbionts. A joint modeling and experimental approach revealed that Ageladine A facilitates photosynthesis of Synechococcus, when the cells are exposed to UV light of 370-380nm wavelength. While Ageladine A absorbs in the UV range, it fluoresces blue, matching the blue absorbance of chlorophyll a. In the presence of Ageladine A, photosynthetic production of O2 increased 2.54- and 3.1-fold, in the experiments and the model, respectively. This study presents a type of symbiosis, in which light is the major currency of species interaction. To verify the applicability of these results to other close relatives of sponge symbionts, two additional strains of Synechococcus sp., and two diatom species, are being tested. The current experiments differ from the initial ones, however, since UV-A radiation of a wider spectrum is used. In addition to these experiments, the applicability of the principle to a wide variety of marine and freshwater algae will be assessed