Yakimov Michail M.

No Thumbnail Available
Last Name
Yakimov
First Name
Michail M.
ORCID

Filters

2008 - 2009 1 2010 - 2015 3
2 2
4
Reset filters

Settings

Search Results

Now showing 1 - 4 of 4
  • Preprint
    Comparison of Niskin vs. in situ approaches for analysis of gene expression in deep Mediterranean Sea water samples
    ( 2014-10) Edgcomb, Virginia P. ; Taylor, Craig D. ; Pachiadaki, Maria G. ; Honjo, Susumu ; Engstrom, Ivory B. ; Yakimov, Michail M.
    Obtaining an accurate picture of microbial processes occurring in situ is essential for our understanding of marine biogeochemical cycles of global importance. Water samples are typically collected at depth and returned to the sea surface for processing and downstream experiments. Metatranscriptome analysis is one powerful approach for investigating metabolic activities of microorganisms in their habitat and which can be informative for determining responses of microbiota to disturbances such as the Deepwater Horizon oil spill. For studies of microbial processes occurring in the deep sea, however, sample handling, pressure, and other changes during sample recovery can subject microorganisms to physiological changes that alter the expression profile of labile messenger RNA. Here we report a comparison of gene expression profiles for whole microbial communities in a bathypelagic water column sample collected in the Eastern Mediterranean Sea using Niskin bottle sample collection and a new water column sampler for studies of marine microbial ecology, the Microbial Sampler – In Situ Incubation Device (MS-SID). For some taxa, gene expression profiles from samples collected and preserved 33 in situ were significantly different from potentially more stressful Niskin sampling and 34 preservation on deck. Some categories of transcribed genes also appear to be affected by sample 35 handling more than others. This suggests that for future studies of marine microbial ecology, 36 particularly targeting deep sea samples, an in situ sample collection and preservation approach 37 should be considered.
  • Preprint
    Protistan community patterns within the brine and halocline of deep hypersaline anoxic basins in the eastern Mediterranean Sea
    ( 2008-10-21) Edgcomb, Virginia P. ; Orsi, William D. ; Leslin, Chesley ; Epstein, Slava S. ; Bunge, John ; Jeon, Sunok ; Yakimov, Michail M. ; Behnke, Anke ; Stoeck, Thorsten
    Environmental factors restrict the distribution of microbial eukaryotes but the exact boundaries for eukaryotic life are not known. Here we examine protistan communities at the extremes of salinity and osmotic pressure, and report rich assemblages inhabiting Bannock and Discovery, two deep-sea superhaline anoxic basins in the Mediterranean. Using a rRNA-based approach, we detected 1538 protistan rRNA gene sequences from water samples with total salinity ranging from 39 g/kg to 280 g/Kg, and obtained evidence that this DNA was endogenous to the extreme habitats sampled. Statistical analyses indicate that the discovered phylotypes represent only a fraction of species actually inhabiting both the brine and the brine-seawater interface, with as much as 82% of the actual richness missed by our survey. Jaccard indices (e.g., for a comparison of community membership) suggest that the brine/interface protistan communities are unique to Bannock and Discovery basins, and share little (0.8-2.8%) in species composition with overlying waters with typical marine salinity and oxygen tension. The protistan communities from the basins’ brine and brine/seawater interface appear to be particularly enriched with dinoflagellates, ciliates and other alveolates, as well as fungi, and are conspicuously poor in stramenopiles. The uniqueness and diversity of brine and brine-interface protistan communities make them promising targets for protistan discovery.
  • Article
    The ocean sampling day consortium
    (BioMed Central, 2015-06-19) Kopf, Anna ; Bicak, Mesude ; Kottmann, Renzo ; Schnetzer, Julia ; Kostadinov, Ivaylo ; Lehmann, Katja ; Fernandez-Guerra, Antonio ; Jeanthon, Christian ; Rahav, Eyal ; Ullrich, Matthias S. ; Wichels, Antje ; Gerdts, Gunnar ; Polymenakou, Paraskevi ; Kotoulas, Georgios ; Siam, Rania ; Abdallah, Rehab Z. ; Sonnenschein, Eva C. ; Cariou, Thierry ; O’Gara, Fergal ; Jackson, Stephen ; Orlic, Sandi ; Steinke, Michael ; Busch, Julia ; Duarte, Bernardo ; Caçador, Isabel ; Canning-Clode, Joao ; Bobrova, Oleksandra ; Marteinsson, Viggo ; Reynisson, Eyjolfur ; Loureiro, Clara Magalhaes ; Luna, Gian Marco ; Quero, Grazia Marina ; Loscher, Carolin R. ; Kremp, Anke ; DeLorenzo, Marie E. ; Øvreås, Lise ; Tolman, Jennifer ; LaRoche, Julie ; Penna, Antonella ; Frischer, Marc ; Davis, Timothy ; Katherine, Barker ; Meyer, Christopher P. ; Ramos, Sandra ; Magalhaes, Catarina ; Jude-Lemeilleur, Florence ; Aguirre-Macedo, Ma Leopoldina ; Wang, Shiao ; Poulton, Nicole ; Jones, Scott ; Collin, Rachel ; Fuhrman, Jed A. ; Conan, Pascal ; Alonso, Cecilia ; Stambler, Noga ; Goodwin, Kelly ; Yakimov, Michail M. ; Baltar, Federico ; Bodrossy, Levente ; Van De Kamp, Jodie ; Frampton, Dion M. F. ; Ostrowski, Martin ; Van Ruth, Paul ; Malthouse, Paul ; Claus, Simon ; Deneudt, Klaas ; Mortelmans, Jonas ; Pitois, Sophie ; Wallom, David ; Salter, Ian ; Costa, Rodrigo ; Schroeder, Declan C. ; Kandil, Mahrous M. ; Amaral, Valentina ; Biancalana, Florencia ; Santana, Rafael ; Pedrotti, Maria Luiza ; Yoshida, Takashi ; Ogata, Hiroyuki ; Ingleton, Timothy ; Munnik, Kate ; Rodriguez-Ezpeleta, Naiara ; Berteaux-Lecellier, Veronique ; Wecker, Patricia ; Cancio, Ibon ; Vaulot, Daniel ; Bienhold, Christina ; Ghazal, Hassan ; Chaouni, Bouchra ; Essayeh, Soumya ; Ettamimi, Sara ; Zaid, El Houcine ; Boukhatem, Noureddine ; Bouali, Abderrahim ; Chahboune, Rajaa ; Barrijal, Said ; Timinouni, Mohammed ; El Otmani, Fatima ; Bennani, Mohamed ; Mea, Marianna ; Todorova, Nadezhda ; Karamfilov, Ventzislav ; ten Hoopen, Petra ; Cochrane, Guy R. ; L’Haridon, Stephane ; Bizsel, Kemal Can ; Vezzi, Alessandro ; Lauro, Federico M. ; Martin, Patrick ; Jensen, Rachelle M. ; Hinks, Jamie ; Gebbels, Susan ; Rosselli, Riccardo ; De Pascale, Fabio ; Schiavon, Riccardo ; dos Santos, Antonina ; Villar, Emilie ; Pesant, Stephane ; Cataletto, Bruno ; Malfatti, Francesca ; Edirisinghe, Ranjith ; Herrera Silveira, Jorge A. ; Barbier, Michele ; Turk, Valentina ; Tinta, Tinkara ; Fuller, Wayne J. ; Salihoglu, Ilkay ; Serakinci, Nedime ; Ergoren, Mahmut Cerkez ; Bresnan, Eileen ; Iriberri, Juan ; Fronth Nyhus, Paul Anders ; Bente, Edvardsen ; Karlsen, Hans Erik ; Golyshin, Peter N. ; Gasol, Josep M. ; Moncheva, Snejana ; Dzhembekova, Nina ; Johnson, Zackary ; Sinigalliano, Christopher D. ; Gidley, Maribeth Louise ; Zingone, Adriana ; Danovaro, Roberto ; Tsiamis, Georgios ; Clark, Melody S. ; Costa, Ana Cristina ; El Bour, Monia ; Martins, Ana M. ; Collins, R. Eric ; Ducluzeau, Anne-Lise ; Martinez, Jonathan ; Costello, Mark J. ; Amaral-Zettler, Linda A. ; Gilbert, Jack A. ; Davies, Neil ; Field, Dawn ; Glockner, Frank Oliver
    Ocean Sampling Day was initiated by the EU-funded Micro B3 (Marine Microbial Biodiversity, Bioinformatics, Biotechnology) project to obtain a snapshot of the marine microbial biodiversity and function of the world’s oceans. It is a simultaneous global mega-sequencing campaign aiming to generate the largest standardized microbial data set in a single day. This will be achievable only through the coordinated efforts of an Ocean Sampling Day Consortium, supportive partnerships and networks between sites. This commentary outlines the establishment, function and aims of the Consortium and describes our vision for a sustainable study of marine microbial communities and their embedded functional traits.
  • Article
    Evidence for isolated evolution of deep-sea ciliate communities through geological separation and environmental selection
    (BioMed Central, 2013-07-08) Stock, Alexandra ; Edgcomb, Virginia P. ; Orsi, William D. ; Filker, Sabine ; Breiner, Hans-Werner ; Yakimov, Michail M. ; Stoeck, Thorsten
    Deep hypersaline anoxic basins (DHABs) are isolated habitats at the bottom of the eastern Mediterranean Sea, which originate from the ancient dissolution of Messinian evaporites. The different basins have recruited their original biota from the same source, but their geological evolution eventually constituted sharp environmental barriers, restricting genetic exchange between the individual basins. Therefore, DHABs are unique model systems to assess the effect of geological events and environmental conditions on the evolution and diversification of protistan plankton. Here, we examine evidence for isolated evolution of unicellular eukaryote protistan plankton communities driven by geological separation and environmental selection. We specifically focused on ciliated protists as a major component of protistan DHAB plankton by pyrosequencing the hypervariable V4 fragment of the small subunit ribosomal RNA. Geospatial distributions and responses of marine ciliates to differential hydrochemistries suggest strong physical and chemical barriers to dispersal that influence the evolution of this plankton group. Ciliate communities in the brines of four investigated DHABs are distinctively different from ciliate communities in the interfaces (haloclines) immediately above the brines. While the interface ciliate communities from different sites are relatively similar to each other, the brine ciliate communities are significantly different between sites. We found no distance-decay relationship, and canonical correspondence analyses identified oxygen and sodium as most important hydrochemical parameters explaining the partitioning of diversity between interface and brine ciliate communities. However, none of the analyzed hydrochemical parameters explained the significant differences between brine ciliate communities in different basins. Our data indicate a frequent genetic exchange in the deep-sea water above the brines. The “isolated island character” of the different brines, that resulted from geological events and contemporary environmental conditions, create selective pressures driving evolutionary processes, and with time, lead to speciation and shape protistan community composition. We conclude that community assembly in DHABs is a mixture of isolated evolution (as evidenced by small changes in V4 primary structure in some taxa) and species sorting (as indicated by the regional absence/presence of individual taxon groups on high levels in taxonomic hierarchy).