Estimation of free glutamic acid in the differentiating central nervous system of the chick

Zusammenfassung Es wird der Gehalt an Glutaminsäure in den embryonalen Entwicklungsstadien des Hühnergehirns festgestellt.     

Specific gravity of cell types in differentiating central nervous system of chick

Zusammenfassung Es wird gezeigt, dass das Gewicht der Nervenzellen ihrem Herkunftsort aus dem Neuralrohr entspricht, das heisst, Vorderhirnzellen sind schwerer als Rückenmarkzellen.     

Mutagenic action of 2-ethyl-2-phenyl-ethyleneimine

Zusammenfassung Die Wirkung von 2-Äthyl-2-phenyl-äthylenimin auf die Induktion von Chlorophyllmutanten bei der Gerste wurde beschrieben. Nach Behandlung mit dem Agens (5 in Wasser) war die Mutationsfrequenz 5,2% für die Ährennachkommenschaften. Die maximale Anzahl Mutanten gehörte zur Viridisklasse (57,9%). Bei höheren Konzentrationen wurde ein beträchtlicher Letaleffekt beobachtet.     

Glucose transporter recycling in response to insulin is facilitated by myosin Myo1c

Insulin stimulates glucose uptake in muscle and adipocytes by signalling the translocation of GLUT4 glucose transporters from intracellular membranes to the cell surface. The translocation of GLUT4 may involve signalling pathways that are both independent of and dependent on phosphatidylinositol-3-OH kinase (PI(3)K). This translocation also requires the actin cytoskeleton, and the rapid movement of GLUT4 along linear tracks may be mediated by molecular motors. Here we report that the unconventional myosin Myo1c is present in GLUT4-containing vesicles purified from 3T3-L1 adipocytes. Myo1c, which contains a motor domain, three IQ motifs and a carboxy-terminal cargo domain, is highly expressed in primary and cultured adipocytes. Insulin enhances the localization of Myo1c with GLUT4 in cortical tubulovesicular structures associated with actin filaments, and this colocalization is insensitive to wortmannin. Insulin-stimulated translocation of GLUT4 to the adipocyte plasma membrane is augmented by the expression of wild-type Myo1c and inhibited by a dominant-negative cargo domain of Myo1c. A decrease in the expression of endogenous Myo1c mediated by small interfering RNAs inhibits insulin-stimulated uptake of 2-deoxyglucose. Thus, myosin Myo1c functions in a PI(3)K-independent insulin signalling pathway that controls the movement of intracellular GLUT4-containing vesicles to the plasma membrane.     

Rapid regulation of steroidogenesis by mitochondrial protein import

Most mitochondrial proteins are synthesized on cytoplasmic ribosomes and imported into mitochondria. The imported proteins are directed to one of four submitochondrial compartments--the outer mitochondrial membrane, the inner mitochondrial membrane, the intramembraneous space, or the matrix--where the protein then functions. Here we show that the steroidogenic acute regulatory protein (StAR), a mitochondrial protein required for stress responses, reproduction, and sexual differentiation of male fetuses, exerts its activity transiently at the outer mitochondrial membrane rather than at its final resting place in the matrix. We also show that its residence time at this outer membrane and its activity are regulated by its speed of mitochondrial import. This may be the first example of a mitochondrial protein exerting its biological activity in a compartment other than that to which it is finally targeted. This system enables steroidogenic cells to initiate and terminate massive levels of steroidogenesis within a few minutes, permitting the rapid regulation of serum steroid hormone concentrations.     

Further studies on the sensitivity of plant pathogenic microorganisms towards some naturally occurring chalcones and flavanones

Summary The antifungal and antibacterial activities of some quinochalcones, chalcones and flavanones isolated fromDidymocarpus pedicellata have been assayed.The authors are grateful to B.C.K.V.V. and CSIR, India, for financial assistance.     

Activation of the innate immune receptor Dectin-1 upon formation of a 'phagocytic synapse'

Innate immune cells must be able to distinguish between direct binding to microbes and detection of components shed from the surface of microbes located at a distance. Dectin-1 (also known as CLEC7A) is a pattern-recognition receptor expressed by myeloid phagocytes (macrophages, dendritic cells and neutrophils) that detects β-glucans in fungal cell walls and triggers direct cellular antimicrobial activity, including phagocytosis and production of reactive oxygen species (ROS). In contrast to inflammatory responses stimulated upon detection of soluble ligands by other pattern-recognition receptors, such as Toll-like receptors (TLRs), these responses are only useful when a cell comes into direct contact with a microbe and must not be spuriously activated by soluble stimuli. In this study we show that, despite its ability to bind both soluble and particulate β-glucan polymers, Dectin-1 signalling is only activated by particulate β-glucans, which cluster the receptor in synapse-like structures from which regulatory tyrosine phosphatases CD45 and CD148 (also known as PTPRC and PTPRJ, respectively) are excluded (Supplementary Fig. 1). The 'phagocytic synapse' now provides a model mechanism by which innate immune receptors can distinguish direct microbial contact from detection of microbes at a distance, thereby initiating direct cellular antimicrobial responses only when they are required.