Muscular and nervous systems of the cubopolyp (Cnidaria)

Summary New observations on the morphology, anatomy, asexual reproduction and metamorphosis of the formerly unknown polyp of the tropical Cubomedusae resulted in the conclusion that a new class Cubozoa must be established and positioned between the Scyphozoa and Hydrozoa. This conclusion could be confirmed by the histological investigation of the cubopolyp's muscular and nervous systems by light and transmission electron microscopy.     

A test of space-time arma modelling and forecasting of hotel data

This paper describes the application of space-time ARMA modelling to demand-related data from eight hotels from a single hotel chain in a large US city. Important spatial characteristics of the space-time process are incorporated into the model using a simple weighting matrix based on driving distances between the hotels. Using a hold-out sample, the forecasting performance of this space-time approach was found to be superior to eight separate univariate ARMA models.     

T-cell recognition of chemicals, protein allergens and drugs: towards the development of in vitro assays

Chemicals can elicit T-cell-mediated diseases such as allergic contact dermatitis and adverse drug reactions. Therefore, testing of chemicals, drugs and protein allergens for hazard identification and risk assessment is essential in regulatory toxicology. The seventh amendment of the EU Cosmetics Directive now prohibits the testing of cosmetic ingredients in mice, guinea pigs and other animal species to assess their sensitizing potential. In addition, the EU Chemicals Directive REACh requires the retesting of more than 30,000 chemicals for different toxicological endpoints, including sensitization, requiring vast numbers of animals. Therefore, alternative methods are urgently needed to eventually replace animal testing. Here, we summarize the outcome of an expert meeting in Rome on 7 November 2009 on the development of T-cell-based in vitro assays as tools in immunotoxicology to identify hazardous chemicals and drugs. In addition, we provide an overview of the development of the field over the last two decades.     

L'action antibiotique de la streptomycine étudiée au microscope électronique

Summary The authors have tried to observe, with the aid of the electron microscope, the effect of streptomycin on the morphology ofB. subtilis. This action is very swift and manifests itself by the appearance of cells with high turgescence (sporical forms, but not resistant), by extreme shrinkage of cytoplasm inside the cell-wall and by the extrusion of this cytoplasm from the cellular envelope.     

Investigation of gas concentration cell based on LiSiPO electrolyte and Li2CO3, Au electrode

Solid lithium ion conducting electrochemical cells using LiSiPO as solid electrolyte and Li₂CO₃ mixed with Au as electrodes were prepared and employed as chemical sensors for the detection of CO₂ gas. The EMF of the cell depends on the concentration of CO₂ in air according to the partial pressure dependence of Nernst’s law in the investigated range from 100 to 2000 ppm over the temperature range from 473 K to 673 K.     

The structural basis for membrane binding and pore formation by lymphocyte perforin

Natural killer cells and cytotoxic T lymphocytes accomplish the critically important function of killing virus-infected and neoplastic cells. They do this by releasing the pore-forming protein perforin and granzyme proteases from cytoplasmic granules into the cleft formed between the abutting killer and target cell membranes. Perforin, a 67-kilodalton multidomain protein, oligomerizes to form pores that deliver the pro-apoptopic granzymes into the cytosol of the target cell. The importance of perforin is highlighted by the fatal consequences of congenital perforin deficiency, with more than 50 different perforin mutations linked to familial haemophagocytic lymphohistiocytosis (type 2 FHL). Here we elucidate the mechanism of perforin pore formation by determining the X-ray crystal structure of monomeric murine perforin, together with a cryo-electron microscopy reconstruction of the entire perforin pore. Perforin is a thin 'key-shaped' molecule, comprising an amino-terminal membrane attack complex perforin-like (MACPF)/cholesterol dependent cytolysin (CDC) domain followed by an epidermal growth factor (EGF) domain that, together with the extreme carboxy-terminal sequence, forms a central shelf-like structure. A C-terminal C2 domain mediates initial, Ca(2+)-dependent membrane binding. Most unexpectedly, however, electron microscopy reveals that the orientation of the perforin MACPF domain in the pore is inside-out relative to the subunit arrangement in CDCs. These data reveal remarkable flexibility in the mechanism of action of the conserved MACPF/CDC fold and provide new insights into how related immune defence molecules such as complement proteins assemble into pores.