To identify the molecular mechanisms involved in phagocytosis, we generated random insertion mutants of<i>Dictyostelium discoideum</i> and selected two defective for phagocytosis. Both represented insertions same gene, named<i>PHG1</i>. This gene encodes a polytopic membrane protein with an N-terminal lumenal domain nine potential transmembrane segments. Homologous genes can be identified many species; however, their function is yet to elucidated. Disruption of <i>PHG1</i> caused selective...

Silver nanowire (AgNW) networks are emerging as one of the most promising alternatives to indium tin oxide (ITO) for transparent electrodes in flexible electronic devices. They can be used a variety optoelectronic applications such solar cells, touch panels and organic light-emitting diodes. Recently they have also proven very efficient when heaters (THs). In addition study AgNW acting THs regular use, i.e. at low voltage moderate temperature, their stability physical behavior higher...

Molecular mechanisms of endocytosis in the genetically and biochemically tractable professional phagocyte Dictyostelium discoideum reveal a striking degree similarity to higher eukaryotic cells. Pulse-chase feeding with latex beads allowed purification phagosomes at different stages maturation. Gentle ATP stripping an actin meshwork entrapping contaminating organelles resulted 10-fold increase yield purity, as confirmed by electron microscopy. Temporal profiling signaling, cytoskeletal,...

Quantitative nucleic acid detection is widely used in molecular diagnostics for infectious diseases. Here, we demonstrate that the previously developed MLFIA (magnetically localized fluorescent immunoassay) has potential to detect Polymerase Chain Reaction (PCR) and loop-mediated isothermal amplification (LAMP) products using biotinylated primers streptavidin-coated magnetic nanoparticles. The functionalized nanoparticles separate amplified DNA from non-incorporated situ, allowing...

Application of a mild hydrodynamic shear stress to Dicytostelium discoideum cells, unable detach cells passively from the substrate, triggers cellular response consisting steady membrane peeling at rear edge cell and periodic contact extensions its front edge. Both processes require an active actin cytoskeleton. The movement induced by forces is very similar amoeboid motion during chemotaxis, as for kinematic parameters involvement phosphatidylinositol(3,4,5)-trisphosphate internal gradient...

Cell arrays are of foremost importance for many applications in pharmaceutical research or fundamental biology. Although arraying techniques have been widely investigated adherent cells, organization cells suspension has rarely considered. The non-adherent using the diamagnetic repulsive force is presented. A planar arrangement Jurkat achieved at microscale above high quality microfabricated permanent magnets with remanent magnetization Jr ≈ 1 T, presence a paramagnetic contrast agent....

cGMP-specific phosphodiesterase (PDE) of vertebrate retinal rod outer segments (ROS) is composed two catalytic subunits (PDE alpha and PDE beta) identical inhibitory gamma). Native beta gamma 2 peripherally bound to the membranes ROS discs. We studied quantitatively its partition between soluble membrane-bound fractions in homogenates. In presence activator, alpha-subunit transducin loaded with a triphosphate guanine nucleotide (T alpha*), displayed greatly enhanced membrane binding. Neither...

Cell spreading is a fundamental event where the contact area with solid substrate increases because of actin polymerization. We propose in this Letter physical model to study growth time. This analysis compared experimental data using ameoba Dictyostelium discoideum. Our couples stress, which builds up at margin when cell spreads, biochemical processes leads scaling characteristic time whose order magnitude compares well our results.

Nonaspanins are characterised by a large N-terminal extracellular domain and nine putative transmembrane domains. This evolutionarily conserved family comprises three members in Dictyostelium discoideum (Phg1A, Phg1B Phg1C) Drosophila melanogaster, four mammals (TM9SF1-TM9SF4), the function of which is essentially unknown. Genetic studies demonstrated that Phg1A required for cell adhesion phagocytosis. We created Phg1A/TM9SF4-null mutant flies showed they were sensitive to pathogenic...

The macropinocytic pathway in Dictyostelium discoideum is organized linearly. After actin-driven internalization, fluid material passes sequentially from endosomes to lysosomes, where molecules are degraded and absorbed. Residual exocytosed via post-lysosomal compartments. Syntaxin 7 a SNARE (soluble N -ethylmaleimide-sensitive fusion protein attachment receptor) that present active D. [Bogdanovic, Bruckert, Morio Satre (2000) J. Biol. Chem. 275, 36691-36697]. Here we report the...

The amoeba Dictyostelium is a simple genetic system for analyzing substrate adhesion, motility and phagocytosis. A new adhesion-defective mutant named phg2 was isolated in this system, PHG2 encodes novel serine/threonine kinase with ras-binding domain. We compared the phenotype of null cells to other previously adhesion mutants evaluate specific role each gene product. Phg1, Phg2, myosin VII, talin all play similar roles cellular adhesion. Like VII talin, Phg2 also involved organization...

Adaptor protein complexes (AP) are major components of the cytoplasmic coat found on clathrin-coated vesicles. Here, we report molecular and functional characterization Dictyostelium clathrin-associated AP-1 complex, which in mammalian cells, participates mainly budding vesicles from trans-Golgi network (TGN). The gamma-adaptin subunit was cloned shown to belong a Golgi-localized 300-kDa complex. Time-lapse analysis cells expressing tagged with green-fluorescent demonstrates dynamics...

The transmembrane 9 (TM9) family of proteins contains numerous members in eukaryotes. Although their function remains essentially unknown higher eukaryotes, the Dictyostelium discoideum Phg1a TM9 protein was recently reported to be essential for cellular adhesion and phagocytosis. Herein, a new divergent member called Phg1b further investigated D. discoideum. phenotypes PHG1a, PHG1b, PHG1a/PHG1b double knockout cells revealed that play synergistic but not redundant role adhesion,...

Application of hydrodynamic mild shear stress to adherent Dictyostelium discoideum vegetative cells triggers active actin cytoskeleton remodeling resulting in net cell movement along the flow. The average speed is strongly stimulated by external calcium (Ca2+, K50%=22 μM), but directionality almost unaffected. This concentration ten times higher than one promoting adhesion glass surfaces (K50%=2 μM). Addition chelator EGTA or Ca2+-channel blocker gadolinium (Gd3+) transiently stops movement....

The best described function of the adaptor complex-1 (AP-1) is to participate in budding clathrin-coated vesicles from trans-Golgi network and endosomes. Here, we show that AP-1 also localized phagocytic cups murine macrophages as well Dictyostelium amoebae. recruited phagosomal membranes at this early stage phagosome formation rapidly dissociates maturing phagosomes. To establish role phagocytosis, made used mutant cells (apm1(-) cells) disrupted for medium chain. In mutant, phagocytosis...

Proteins of the Chediak-Higashi/Beige (BEACH) family have been implicated in function lysosomes, as well signal transduction, but their molecular role is still poorly understood. In Dictyostelium, at least six members can be identified. Here cells with mutations two these genes, LVSA and LVSB, were analyzed. Interestingly both mutants exhibited defects organization endocytic pathway,albeit distinct stages. lvsB mutant cells, regulated secretion lysosomal enzymes was enhanced, a phenotype...