Postcranial morphology of a basal Pistosauroidea (Sauropterygia) from the Lower Muschelkalk of Winterswijk,The Netherlands

Two partial postcranial skeletons from the Lower Muschelkalk (early Anisian) of Winterswijk, The Netherlands, are described in detail. The specimens were assigned to basal Pistosauroidea, presumably to cf. Cymatosaurus or a closely related taxon. Cymatosaurus is currently the earliest member of the Pistosauroidea and is only known from skull material. Taxonomical assignment is based on humerus morphology and histology, and on morphological differences from other Sauropterygia (Nothosauria and Pachypleurosauria).     

Two functional types of attachment pads on a single foot in the Namibia bush cricket Acanthoproctus diadematus (Orthoptera: Tettigoniidae)

Insects have developed different structures to adhere to surfaces. Most common are smooth and hairy attachment pads, while nubby pads have also been described for representatives of Mantophasmatodea, Phasmida and Plecoptera. Here we report on the unusual combination of nubby and smooth tarsal attachment structures in the !nara cricket Acanthoproctus diadematus. Their three proximal tarsal pads (euplantulae) have a nubby surface, whereas the most distal euplantula is rather smooth with a hexagonal ground pattern resembling that described for the great green bush-cricket Tettigonia viridissima. This is, to our knowledge, the first report on nubby euplantulae in Orthoptera and the co-occurrence of nubby and smooth euplantulae on a single tarsus in a polyneopteran species. When adhering upside down to a horizontal glass plate, A. diadematus attaches its nubby euplantulae less often, compared to situations in which the animal is hanging upright or head down on a vertical plate. We discuss possible reasons for this kind of clinging behaviour, such as morphological constrains, the different role of normal and shear forces in attachment enhancement of the nubby and smooth pads, ease of the detachment process, and adaptations to walking on cylindrical substrates.     

Demyelinating myelin oligodendrocyte glycoprotein-specific autoantibody response is focused on one dominant conformational epitope region in rodents

Conformational epitopes of myelin oligodendrocyte glycoprotein (MOG) provide a major target for demyelinating autoantibodies in experimental autoimmune encephalomyelitis and recent studies indicate that a similar situation may exist in multiple sclerosis. We recently solved the crystal structure of the extracellular domain of MOG (MOG(ex)) in complex with a Fab derived from the demyelinating mAb 8-18C5 and identified the conformational 8-18C5 epitope on MOG that is dominated by the surface exposed FG loop of MOG. To determine the importance of this epitope with regard to the polyclonal Ab response to MOG(ex) we investigated the effects of mutating His(103) and Ser(104), the two central amino acids of the FG loop, on Ab binding. Mutation of these two residues reduced binding of a panel of eight demyelinating conformation-dependent mAbs to <20% compared with binding to wild-type MOG(ex), whereas substitution of amino acids that do not contribute to the 8-18C5 epitope had only a minor effect on Ab binding. The same restriction was observed for the polyclonal MOG-specific Ab response of MOG DNA-vaccinated BALB/c and SJL/J mice. Our data demonstrate that the pathogenic anti-MOG Ab response primarily targets one immunodominant region centered at the FG loop of MOG. Comparison of the structure of MOG(ex) with the structures of related IgV-like domains yields a possible explanation for the focused Ab response.     

The costs of copulating in the dung fly Sepsis cynipsea

Finding, assessing, rejecting, and copulating with a mate isassumed to carry fitness costs, particularly for females, thathave to be traded off against fitness benefits of mating suchas increased fecundity, fertility, longevity, or better qualityoffspring. Female dung flies, Sepsis cynipsea (Diptera: Sepsidae),typically attempt to dislodge mounted males harassing themby vigorous shaking. Shaking duration has been shown to reflect both direct and indirect female choice in this species. Thelatter is an expression of the females' general reluctanceto mate due to presumed costs of mating. We investigated thecosts of copulation in the laboratory. Females were randomlyassigned to one of three treatment groups and allowed to copulateeither not at all, once, or twice. The males' armored genitalia injured females internally during copula. Injuries were visibleas sclerotized scars in the female ovipositor, and their occurrenceincreased with mating frequency. Presumably due to these injuries,mated females showed higher mortality. This effect was statisticallyindependent from additional costs of reproduction related tooviposition, as copulation also increased lifetime egg productionand tended to augment oviposition rate (eggs per day), while fertility (proportion of offspring emerged) was unaffected.We thus found high mortality costs of copulating, indicatingsubstantial sexual conflict, which helps explain female reluctanceto mate in this species.     

Plant diversity in a water-meadow landscape: the role of irrigation ditches

Species-rich, extensively managed grasslands are among the most threatened ecosystems in Europe. The traditional technique of meadow irrigation, formerly practised in large parts of Europe, may be a viable management option that meets both ecological and economical objectives. While studies on plant diversity of the meadow matrix exist, the role of other landscape components for biodiversity conservation is unknown. We quantify the role of irrigation and drainage ditches compared with field paths, and analysed the local and landscape plant species composition and diversity in a water-meadow landscape. The meadows are located in the river Queich catchment (Upper Rhine valley, Germany). We recorded plant species cover on 18 meadows, adjacent ditches and field paths and analysed alpha, beta and gamma diversity within and among these landscape components. Irrigation and drainage ditches were more species rich than meadows and more heterogeneous in their species composition compared with meadows and paths. Ditches contributed one-third of the landscape’s plant species numbers, habitat for wetland species and refuges for high nature value grassland species. Fertilization of the adjacent meadow had no negative impact on the ditch diversity, while well-maintained ditches were more plant species rich than ditches filled with sediments. Traditional flood meadow irrigation should be taken into account when sustainable grassland management techniques are discussed that meet economical and ecological needs. A major contribution to landscape richness arises from the ditch structures as crucial part of the traditional irrigation technique.     

Recent developments in the chemistry of sandalwood odorants

Natural sandalwood oil, a unique and valuable ingredient in fine perfumery, has been the focus of scientific interest for many years. Due to its scarcity and its high price, the search for novel synthetic raw materials imitating the characteristic odor profile of sandalwood oil is as challenging as ever. In this context, the preparation of the novel sandalwood odorants 26, 33, and 39 will be discussed, including their sensory properties and structure-odor relationship.     

Production of nitric oxide by carp (Cyprinus carpio L.) kidney leukocytes is regulated by cyclic 3',5'-adenosine monophosphate

The inducible nitric oxide synthase (iNOS) plays a central role in the inflammatory reactions that follow infection or tissue damage. Induction of nitric oxide (NO) synthesis by bacterial lipopolysaccharide (LPS) depends on activation of G protein-coupled receptors in mammals. Thus, it was our intention to evaluate whether similar mechanisms are involved in iNOS activation in fish leukocytes. Therefore, the participation of membrane-bound receptors which activate effectors via G proteins has been confirmed using the G protein inhibitor suramin. Furthermore, the NO produced by iNOS performs both beneficial and detrimental actions. It is thus conceivable that regulatory mechanisms exist which control the timing and intensity of NO production by iNOS in order to outweigh protective effects against detrimental ones. The second messenger cAMP produced by adenylyl cyclases (ACs) plays a key role in the regulation of many cellular functions. Since cAMP signaling inhibits numerous immunological reactions, studies have been carried out to determine whether cAMP-dependent pathways could inhibit NO production by carp leukocytes as well. To measure cellular responses such as NO production by carp leukocytes derived from head and trunk kidneys treatments were performed with the cAMP elevating agents forskolin and dibutyryl-cAMP (db-cAMP) prior to stimulation with Aeromonas hydrophila. Pharmacological studies in stimulated kidney leukocytes showed that increased intracellular cAMP levels lead to reduced NO formation. This reduction of NO production was not due to decreased cell numbers, since a tetrazolium dye-based assay revealed no reduction of cell viability by cyclic nucleotide elevating agents. Thus, our data provide evidence that the AC/cAMP signaling pathway is well established in carp leukocytes. Cyclic AMP leads to type II immune response. We provide evidence that the predominant AC in fish leukocytes is a particulate enzyme due to its sensitivity to forskolin. Treatment of leukocytes with agents increasing intracellular cAMP gave clear evidence for participation of this cyclic nucleotide in immune signaling.     

Caldendrin-Jacob: a protein liaison that couples NMDA receptor signalling to the nucleus

NMDA (N-methyl-D-aspartate) receptors and calcium can exert multiple and very divergent effects within neuronal cells, thereby impacting opposing occurrences such as synaptic plasticity and neuronal degeneration. The neuronal Ca2+ sensor Caldendrin is a postsynaptic density component with high similarity to calmodulin. Jacob, a recently identified Caldendrin binding partner, is a novel protein abundantly expressed in limbic brain and cerebral cortex. Strictly depending upon activation of NMDA-type glutamate receptors, Jacob is recruited to neuronal nuclei, resulting in a rapid stripping of synaptic contacts and in a drastically altered morphology of the dendritic tree. Jacob's nuclear trafficking from distal dendrites crucially requires the classical Importin pathway. Caldendrin binds to Jacob's nuclear localization signal in a Ca2+-dependent manner, thereby controlling Jacob's extranuclear localization by competing with the binding of Importin-alpha to Jacob's nuclear localization signal. This competition requires sustained synapto-dendritic Ca2+ levels, which presumably cannot be achieved by activation of extrasynaptic NMDA receptors, but are confined to Ca2+ microdomains such as postsynaptic spines. Extrasynaptic NMDA receptors, as opposed to their synaptic counterparts, trigger the cAMP response element-binding protein (CREB) shut-off pathway, and cell death. We found that nuclear knockdown of Jacob prevents CREB shut-off after extrasynaptic NMDA receptor activation, whereas its nuclear overexpression induces CREB shut-off without NMDA receptor stimulation. Importantly, nuclear knockdown of Jacob attenuates NMDA-induced loss of synaptic contacts, and neuronal degeneration. This defines a novel mechanism of synapse-to-nucleus communication via a synaptic Ca2+-sensor protein, which links the activity of NMDA receptors to nuclear signalling events involved in modelling synapto-dendritic input and NMDA receptor-induced cellular degeneration.     

Characterization of proteins associated with heat shock protein hsp27 in the squamous cell carcinoma cell line A431.

Heat shock protein hsp27 is a molecular chaperone and identification of hsp27-binding proteins might help to elucidate its functional role in keratinocyte biology. In the present investigation we used a human epidermal cell carcinoma cell line (A431) transfected with hsp27 (A431/16) to study interference between hsp27 protein and other proteins. Immunoprecipitation experiments with anti-hsp27 antibody revealed a multicomponent complex when analysed by silver staining. By immunoblotting analysis we could demonstrate that hsp27 associates with actin, the mutant form of p53, hsp70 and hsp90. Immunofluorescence analysis showed a co-localization between hsp27 and p53, hsp70 and hsp90. To control for the specificity of the observed interactions, immuno-precipitations with antibodies to actin, p53, hsp70 and hsp90 respectively, were performed. All of the tested proteins demonstrated a coimmunoprecipitation with hsp27. We conclude that hsp27, like the other heat shock proteins, is part of a complex system of molecular chaperones in epidermal keratinocytes.     

Size-Dependent Mating Success at Various Nutritional States in the Yellow Dung Fly

Mating success not only depends on genetic quality, but also equally on environmental factors, most prominently food availability. We investigated the interactive effects of nutritional state and body size on mating success and copula duration in yellow dung fly males ( Scathophaga stercoraria ; Diptera: Scathophagidae) of three body size selection lines in the laboratory in both non-competitive (single) and competitive (group) situations. Adults require protein and lipids from prey to reproduce, as well as sugars as an energy source for reproductive activity. We expected mating success to decrease with time because of sperm depletion (sugar treatment) and/or energy shortage (water treatment) relative to the control, prey plus sugar treatment. Based on physiological scaling, we also expected large-line males to become depleted either sooner because of their higher energy and sperm demands, or later because of their more efficient energy use. Average mating success indeed declined over a period of 5–7 d (or 5–15 potential copulations per male), but equally for all food treatments and body size classes. Surprisingly, water-fed and small-line males had the highest mating probability in the non-competitive setting, while in the competitive setting large-line males had the highest success. Energy-depleted males showed apparent terminal investment. Small males acquired females more readily but eventually lost them to larger males in the competitive situation. As shown before, copula duration was inversely related to body size and increased with copulation number, independent of food treatment. We conclude that sugar or prey shortage has little effect on mating success in the short term, and does not differentially affect males of different sizes.