dictyNews Electronic Edition Volume 40, number 13 May 16, 2014 Please submit abstracts of your papers as soon as they have been accepted for publication by by using the form at http://dictybase.org/db/cgi-bin/dictyBase/abstract_submit or by sending them to dicty@northwestern.edu 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 ========= Potential role of bacteria packaging by protozoa in the persistence and transmission of pathogenic bacteria Alix M. Denoncourt1,2, Valˇrie E. Paquet1,2 and Steve J. Charette1,2,3* 1. Institut de Biologie Intˇgrative et des Syst¸mes (IBIS), Canada 2. Centre de recherche de l'institut universitaire en cardiologie et pneumologie de Quˇbec, Canada 3. Dˇpartement de biochimie, microbiologie et bio-informatique, Universitˇ Laval, Canada Front. Microbiol. | doi: 10.3389/fmicb.2014.00240 (Hypothesis & theory article) http://journal.frontiersin.org/Journal/10.3389/fmicb.2014.00240/abstract) Many pathogenic bacteria live in close association with protozoa. These unicellular eukaryotic microorganisms are ubiquitous in various environments. A number of protozoa such as amoebae and ciliates ingest pathogenic bacteria, package them usually in membrane structures, and then release them into the environment. Packaged bacteria are more resistant to various stresses and are more apt to survive than free bacteria. New evidence indicates that protozoa and not bacteria control the packaging process. It is possible that packaging is more common than suspected and may play a major role in the persistence and transmission of pathogenic bacteria. To confirm the role of packaging in the propagation of infections, it is vital that the molecular mechanisms governing the packaging of bacteria by protozoa be identified as well as elements related to the ecology of this process in order to determine whether packaging acts as a Trojan Horse. Submitted by Steve Charette [Steve.Charette@bcm.ulaval.ca] --------------------------------------------------------------------------- Secondary Ion Mass Spectrometry Imaging of Dictyostelium discoideum Aggregation Streams J. Daniel DeBord1, Donald F. Smith2, Christopher R. Anderton3, Ron M.A. Heeren2, Ljiljana Pasa-Tolc 3, Richard H. Gomer4, and Francisco A. Fernandez-Lima1* 1Department of Chemistry and Biochemistry, Florida International University, Miami, FL 33199, USA 2 FOM Institute AMOLF, Science Park 104, 1098 XG Amsterdam, The Netherlands 3 Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, Washington 99352, USA 4Department of Biology, Texas A&M University, College Station, TX 77843, USA PLoS ONE, in press High resolution imaging mass spectrometry could become a valuable tool for cell and developmental biology, but both, high spatial and mass spectral resolution are needed to enable this. In this report, we employed Bi3 bombardment time-of-flight (Bi3 ToF-SIMS) and C60 bombardment Fourier transform ion cyclotron resonance secondary ion mass spectrometry (C60 FTICR-SIMS) to image Dictyostelium discoideum aggregation streams. Nearly 300 lipid species were identified from the aggregation streams. High resolution mass spectrometry imaging (FTICR-SIMS) enabled the generation of multiple molecular ion maps at the nominal mass level and provided good coverage for fatty acyls, prenol lipids, and sterol lipids. The comparison of Bi3 ToF-SIMS and C60 FTICR-SIMS suggested that while the first provides fast, high spatial resolution molecular ion images, the chemical complexity of biological samples warrants the use of high resolution analyzers for accurate ion identification. Submitted by Richard Gomer [rgomer@tamu.edu] --------------------------------------------------------------------------- Erika Kovacs-Bogdan , Yasemin Sancak , Kimberli J. Kamer , Molly Plovanich , Ashwini Jambhekar , Robert J. Huber , Michael A Myre , Michael D Blower and Vamsi K. Mootha Reconstitution of the mitochondrial calcium uniporter in yeast. Proceedings of the National Academy of Sciences, USA in press The mitochondrial calcium uniporter is a highly selective calcium channel distributed broadly across eukaryotes but absent in the yeast S. cerevisiae. In recent years, the molecular components of the human uniporter holocomplex (uniplex) have been identified. It consists of three membrane-spanning subunits (MCU, its paralogue MCUb, and EMRE) and two soluble regulatory components (MICU1 and its paralogue MICU2). At present, the minimal components sufficient for in vivo uniporter activity are not known. Here, we consider Dictyostelium discoideum (Dd), a member of amoebazoa, which is the outgroup of metazoa and fungi, and show that it has a highly simplified uniporter machinery. We show that D. discoideum mitochondria exhibit membrane potential-dependent calcium uptake compatible with uniporter activity. Furthermore, expression of DdMCU complements the mitochondrial calcium uptake defect in human cells lacking MCU or EMRE. Moreover, expression of DdMCU in yeast alone is sufficient to reconstitute mitochondrial calcium uniporter activity. Having established yeast as an in vivo reconstitution system, we then reconstituted the human uniporter. We show that co-expression of MCU and EMRE is sufficient for uniporter activity, whereas expression of MCU alone is not sufficient. Our work establishes yeast as a powerful in vivo reconstitution system for the uniporter. Using this system we confirm that MCU is the pore-forming subunit, define the minimal genetic elements sufficient for a metazoan and a non-metazoan uniporter activity, and provide valuable insights into the evolution of the uniporter machinery. Submitted by Michael Myre [myre@chgr.mgh.harvard.edu] ============================================================== [End dictyNews, volume 40, number 13]