dictyNews Electronic Edition Volume 42, number 24 October 14, 2016 Please submit abstracts of your papers as soon as they have been accepted for publication by sending them to dicty@northwestern.edu or by using the form at http://dictybase.org/db/cgi-bin/dictyBase/abstract_submit. Back issues of dictyNews, the Dicty Reference database and other useful information is available at dictyBase - http://dictybase.org. Follow dictyBase on twitter: http://twitter.com/dictybase ========= Abstracts ========= Terpene synthase genes in eukaryotes beyond plants and fungi: Occurrence in social amoebae Xinlu Chen, Tobias G. Köllner, Qidong Jia, Ayla Norris, Balaji Santhanam, Patrick Rabe, Jeroen Dickschat, Gad Shaulsky, Jonathan Gershenzon, and Feng Chen Department of Plant Sciences, University of Tennessee, Knoxville, TN 37996 Max Planck Institute for Chemical Ecology, D-07745 Jena, Germany Graduate School of Genome Science and Technology, University of Tennessee, Knoxville, TN 37996 Graduate Program in Structural Computational Biology and Molecular Biophysics, Baylor College of Medicine, Houston, TX 77030 Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030 Kekulé-Institute of Organic Chemistry and Biochemistry, University of Bonn, 53121 Bonn, Germany PNAS, in press Terpenes are structurally diverse natural products involved in many ecological interactions. The pivotal enzymes for terpene biosynthesis, terpene synthases (TPSs), had been described only in plants and fungi in the eukaryotic domain. In this report, we systematically analyzed the genome sequences of a broad range of nonplant/nonfungus eukaryotes and identified putative TPS genes in six species of amoebae, five of which are multicellular social amoebae from the order of Dictyosteliida. A phylogenetic analysis revealed that amoebal TPSs are evolutionarily more closely related to fungal TPSs than to bacterial TPSs. The social amoeba Dictyostelium discoideum was selected for functional study of the identified TPSs. D. discoideum amoebae grow as unicellular organisms, whereas digesting bacteria and switch from vegetative growth to multicellular development upon starvation. We found that expression of most D. discoideum TPS genes was induced during development. Upon heterologous expression, all nine TPSs from D. discoideum showed sesquiterpene synthase activities. Some also exhibited monoterpene and/or diterpene synthase activities. Direct measurement of volatile terpenes in cultures of D. discoideum revealed essentially no emission at an early stage of development. In contrast, a bouquet of terpenes, dominated by sesquiterpenes including beta-barbatene and (E,E)-alpha- farnesene, was detected at the middle and late stages of development, suggesting a development-specific function of volatile terpenes in D. discoideum. The patchy distribution of TPS genes in the eukaryotic domain and the evidence for TPS function in D. discoideum indicate that the TPS genes mediate lineage-specific adaptations. submitted by: Gad Shaulsky [gadi@bcm.edu] ——————————————————————————————————————— The Dictyostelium discoideum as a novel host system to study the interaction between phagocytes and yeasts Barbara Koller, Christin Schramm, Susann Siebert, János Triebel, Eric Deland, Anna M. Pfefferkorn, Volker Rickerts and Sascha Thewes. Front. Microbiol. 7:1665. doi: 10.3389/fmicb.2016.01665 The social amoeba Dictyostelium discoideum is a well-established model organism to study the interaction between bacteria and phagocytes. In contrast, research using D. discoideum as a host model for fungi is rare. We describe a comprehensive study, which uses D. discoideum as a host model system to investigate the interaction with apathogenic (Saccharomyces cerevisiae) and pathogenic (Candida sp.) yeast. We show that Dictyostelium can be co-cultivated with yeasts on solid media, offering a convenient test to study the interaction between fungi and phagocytes. We demonstrate that a number of D. discoideum mutants increase (atg1-, kil1-, kil2-) or decrease (atg6-) the ability of the amoebae to predate yeast cells. On the yeast side, growth characteristics, reduced phagocytosis rate, as well as known virulence factors of C. albicans (EFG1, CPH1, HGC1, ICL1) contribute to the resistance of yeast cells against predation by the amoebae. Investigating haploid C. albicans strains, we suggest using the amoebae plate test for screening purposes after random mutagenesis. Finally, we discuss the potential of our adapted amoebae plate test to use D. discoideum for risk assessment of yeast strains. submitted by: Sascha Thewes [sascha.thewes@fu-berlin.de] ——————————————————————————————————————— The microfluidic lighthouse: an omnidirectional gradient generator A. Nakajima (a), M. Ishida (b), T. Fujimori (b), Y. Wakamoto (a,b) and S. Sawai (*a,b,c) a Research Center for Complex Systems Biology, Graduate School of Arts and Sciences, The University of Tokyo, Japan b Department of Basic Science, Graduate School of Arts and Sciences, The University of Tokyo, Japan c PRESTO, Japan Science and Technology Agency, Japan Lab Chip, 2016 (in press) DOI: 10.1039/c6lc00898d Studies of chemotactic cell migration rely heavily on various assay systems designed to evaluate the ability of cells to move in response to attractant molecules. In particular, the development of microfluidics-based devices in recent years has made it possible to spatially distribute attractant molecules in graded profiles that are sufficiently stable and precise to test theoretical predictions regarding the accuracy and efficiency of chemotaxis and the underlying mechanism of stimulus perception. However, because the gradient is fixed in a direction orthogonal to the laminar flow and thus the chamber geometry, conventional devices are limited for the study of cell re-orientation to gradients that move or change directions. Here, we describe the development of a simple radially symmetric microfluidics device that can deliver laminar flow in 360°. A stimulant introduced either from the central inlet or by photo uncaring is focused into the laminar flow in a direction determined by the relative rate of regulated flow from multiple side channels. Schemes for flow regulation and an extended duplexed device were designed to generate and move gradients in desired orientations and speed, and then tested to steer cell migration of Dictyostelium and neutrophil-like HL60 cells. The device provided a high degree of freedom in the positioning and orientation of attractant gradients, and thus may serve as a versatile platform for studying cell migration, re-orientation, and steering. submitted by: Satoshi Sawai [cssawai@mail.ecc.u-tokyo.ac.jp] ============================================================== [End dictyNews, volume 42, number 24]