Localization and density of phoretic deutonymphs of the mite Uropoda orbicularis (Parasitiformes : Mesostigmata) on Aphodius beetles (Aphodiidae) affect pedicel length

The phoretic stage of Uropodina mites is a deutonymph with developed morphological adaptations for dispersal by insects. Phoretic deutonymphs are able to produce a pedicel, a stalk-like temporary attachment structure that connects the mite with the carrier. The aim of our study was to determine whether localization and density of phoretic deutonymphs on the carrier affect pedicel length. The study was conducted on a common phoretic mite-Uropoda orbicularis (Uropodina) and two aphodiid beetles-Aphodius prodromus and Aphodius distinctus. Our results show that pedicel length is influenced by the localization of deutonymphs on the body of the carrier. The longest pedicels are produced by deutonymphs attached to the upper part of elytra, whereas deutonymphs attached to femora and trochanters of the third pair of legs and the apex of elytra construct the shortest pedicels. In general, deutonymphs attached to more exposed parts of the carrier produce longer pedicels, whereas shorter pedicels are produced when deutonymphs are fixed to non-exposed parts of the carrier. A second factor influencing pedicel length is the density of attached deutonymphs. Mean pedicel length and deutonymph densities were highly correlated: higher deutonymph density leads to the formation of longer pedicels. The cause for this correlation is discussed, and we conclude that pedicel length variability can increase successful dispersal

Artificial Skin – Culturing of Different Skin Cell Lines for Generating an Artificial Skin Substitute on Cross-Weaved Spider Silk Fibres

Background: In the field of Plastic Reconstructive Surgery the development of new innovative matrices for skin repair is in urgent need. The ideal biomaterial should promote attachment, proliferation and growth of cells. Additionally, it should degrade in an appropriate time period without releasing harmful substances, but not exert a pathological immune response. Spider dragline silk from Nephila spp meets these demands to a large extent. Methodology/Principal Findings: Native spider dragline silk, harvested directly out of Nephila spp spiders, was woven on steel frames. Constructs were sterilized and seeded with fibroblasts. After two weeks of cultivating single fibroblasts, keratinocytes were added to generate a bilayered skin model, consisting of dermis and epidermis equivalents. For the next three weeks, constructs in co-culture were lifted on an originally designed setup for air/liquid interface cultivation. After the culturing period, constructs were embedded in paraffin with an especially developed program for spidersilk to avoid supercontraction. Paraffin cross-sections were stained in Haematoxylin & Eosin (H&E) for microscopic analyses. Conclusion/Significance: Native spider dragline silk woven on steel frames provides a suitable matrix for 3 dimensional skin cell culturing. Both fibroblasts and keratinocytes cell lines adhere to the spider silk fibres and proliferate. Guided by the spider silk fibres, they sprout into the meshes and reach confluence in at most one week. A well-balanced, bilayered cocultivation in two continuously separated strata can be achieved by serum reduction, changing the medium conditions and the cultivation period at the air/liquid interphase. Therefore spider silk appears to be a promising biomaterial for the enhancement of skin regeneration

Mesenchymale Stammzellen: Eigenschaften und klinisches Potential für zellbasierte Therapien in der rekonstruktiven Chirurgie mit dem Schwerpunkt der peripheren Nervenchirurgie

The isolation and expansion of multipotent mesenchymal stem cells (MSCs) could be demonstrated from bone marrow, peripheral blood, skin, umbilical cord blood and adipose issue. They can be differentiated to different mesodermal cell lines like bone, cartilage, muscle or adipose tissue cells in vitro as well as in vivo . Thus MSCs represent an attractive cell population for the substitution of mesenchymal tissues via tissue engineering due to their potential of differentiation and their favourable expansion properties. In contrast to embryonic stem cells (ESCs) they have the advantage that they can be autologously harvested in high numbers. Besides, there are fewer ethical issues in the use of MSCs. Another advantage of MSCs is the highly regenerative secretion profile of cytokines and growth factors, in particular supporting angiogenesis. A plethora of studies describe the morphological and phenotypical characterization of this cell type as well as regulatory mechanisms underlying the differentiation into specific tissues aiming to optimize in vitro conditions for differentiation and thus clinical application. This review describes the definition of a mesenchymal stem cell, methods for isolation and phenotypical characterization, possibilities of differentiation and possible therapeutical applications of MSCs.Die Isolierung und die Expansion pluripotenter mesenchymaler Stammzellen (MSCs) konnte aus Knochenmark, peripherem Blut, Haut, Nabelschnurblut und Fettgewebe demonstriert werden. Sie können sich zu verschiedenen mesodermalen Zellarten wie Knochen-, Knorpel-, Muskel- oder Fettzellen sowohl in vitro wie auch in vivo differenzieren. Somit stellen die MSCs aufgrund ihres mesenchymalen Differenzierungspotentials und ihrer guten in vitro- Expansionseigenschaften eine attraktive Zellpopulation für den Ersatz mesenchymaler Gewebe für das Tissue Engineering (TE) dar. Im Gegensatz zu embryonalen Stammzellen (ESCs) haben sie den Vorteil, dass sie in ausreichend hoher Zellzahl autolog gewonnen werden können. Darüber hinaus bestehen bei den MSCs keine ethischen Problemstellungen. Ein weiterer Vorteil von mesenchymalen Stammzellen ist ihr hochgradig regeneratives, insbesondere Angiogenese förderndes Sekretionsprofil von Zytokinen und Wachstumsfaktoren. Eine Vielzahl von Studien beschreibt die morphologische und phänotypische Charakterisierung dieser Zellart und Regulationsmechanismen bei der Differenzierung in bestimmte Gewebespezifikationen mit dem Ziel, die in vitro- Konditionen zur Differenzierung zu optimieren und um somit die klinische Anwendung zu erleichtern.Dieser Übersichtsartikel beschreibt die Definition der mesenchymalen Stammzellen, die Methoden zur Isolierung und phänotypischen Charakterisierungen, die Differenzierungsmöglichkeiten und mögliche therapeutische Anwendungen der MSCs