Properties of vascular permeability factor in human sera for guinea-pig skin.

Properties of vascular permeability factor in native human sera (PF/Nat) showed close similarities with those of necrotizing factor. Time course studies revealed that skin necrosis could be initiated by enhanced vascular permeability.     

Receptor potential of rat taste cell to potassium benzoate.

Rat taste cells responded to relatively low concentrations of K-benzoate with a hyperpolarization and to the high concentrations with a depolarization. During both responses the membrane resistance of a taste cell decreased. Depolarization elicited by application of a combination of 0.25 M NaCl and 0.05 M K-benzoate was smaller than that by the NaCl alone, indicating a depressant action of K-benzoate.     

Occurrence of Rhodoquinone-9 in the muscle of ascaris lumbricoides var. suis

Zusammenfassung Es gelang, aus der Epithelmuskelzelle vonAscaris lumbricoides var.suis Rhodochinon (Methoxylgruppe in Ubichinon mit einer Aminogruppe substituiert) zu extrahieren und kristallin zu gewinnen. Die Spektralmessungen (UV-, IR-, Massen-Spektren) ergeben, dass es sich beim Rhodochinon um Rhodochinon-9 handelt.     

Properties of vascular permeability factor in human sera for guinea-pig skin

Summary Properties of vascular permeability factor in native human sera (PF/Nat) showed close similarities with those of necrotizing factor. Time course studies revealed that skin necrosis could be initiated by enhanced vascular permeability.Acknowledgment. The authors wish to thank Prof. H. Hayashi, Kumamoto University for encouragement and discussions.     

Intestinal epithelial barrier and mucosal immunity

The mucosal immune system maintains a delicate balance between providing robust defense against infectious pathogens and, at the same time, regulating responses toward innocuous environmental and food antigens and commensal microbes. The Peyer's patch (PP) has been studied in detail as a major inductive site for mucosal immunity within the small intestine. While the mechanisms responsible for the induction of mucosal immunity versus tolerance are not yet fully understood, recent studies have highlighted mucosal dendritic cells (DCs) as regulators of the immune responses to orally administered antigens. Here we discuss recent studies that describe the role of PP DCs in immune induction and speculate on the mechanism by which the resident DCs regulate T cell and immunoglobulin A (IgA) responses in the gastrointestinal mucosa.     

Lipid-protein interactions in double-layered two-dimensional AQP0 crystals

Lens-specific aquaporin-0 (AQP0) functions as a specific water pore and forms the thin junctions between fibre cells. Here we describe a 1.9 A resolution structure of junctional AQP0, determined by electron crystallography of double-layered two-dimensional crystals. Comparison of junctional and non-junctional AQP0 structures shows that junction formation depends on a conformational switch in an extracellular loop, which may result from cleavage of the cytoplasmic amino and carboxy termini. In the centre of the water pathway, the closed pore in junctional AQP0 retains only three water molecules, which are too widely spaced to form hydrogen bonds with each other. Packing interactions between AQP0 tetramers in the crystalline array are mediated by lipid molecules, which assume preferred conformations. We were therefore able to build an atomic model for the lipid bilayer surrounding the AQP0 tetramers, and we describe lipid-protein interactions.     

Differential roles of MDA5 and RIG-I helicases in the recognition of RNA viruses

The innate immune system senses viral infection by recognizing a variety of viral components (including double-stranded (ds)RNA) and triggers antiviral responses. The cytoplasmic helicase proteins RIG-I (retinoic-acid-inducible protein I, also known as Ddx58) and MDA5 (melanoma-differentiation-associated gene 5, also known as Ifih1 or Helicard) have been implicated in viral dsRNA recognition. In vitro studies suggest that both RIG-I and MDA5 detect RNA viruses and polyinosine-polycytidylic acid (poly(I:C)), a synthetic dsRNA analogue. Although a critical role for RIG-I in the recognition of several RNA viruses has been clarified, the functional role of MDA5 and the relationship between these dsRNA detectors in vivo are yet to be determined. Here we use mice deficient in MDA5 (MDA5-/-) to show that MDA5 and RIG-I recognize different types of dsRNAs: MDA5 recognizes poly(I:C), and RIG-I detects in vitro transcribed dsRNAs. RNA viruses are also differentially recognized by RIG-I and MDA5. We find that RIG-I is essential for the production of interferons in response to RNA viruses including paramyxoviruses, influenza virus and Japanese encephalitis virus, whereas MDA5 is critical for picornavirus detection. Furthermore, RIG-I-/- and MDA5-/- mice are highly susceptible to infection with these respective RNA viruses compared to control mice. Together, our data show that RIG-I and MDA5 distinguish different RNA viruses and are critical for host antiviral responses.     

Activation of aldosterone and renin secretion by thermal stress

Résumé Un stress thermique aigu est un activateur rapide et puissant de la sécrétion du système rénineangiotensine et de l'aldosterone au cours d'une alimentation normo ou hyposodée, et peut être utilisé pour mesurer l'intégrité des systèmes de production de ces hormones.