Koch Florian

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Koch
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Florian
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  • Article
    A novel immunofluorescence flow cytometry technique detects the expansion of brown tides caused by Aureoumbra lagunensis to the Caribbean Sea
    (American Society for Microbiology, 2014-06-06) Koch, Florian ; Kang, Y. ; Villareal, Tracy A. ; Anderson, Donald M. ; Gobler, Christopher J.
    During the past 3 decades, brown tides caused by the pelagophytes Aureococcus anophagefferens and Aureoumbra lagunensis have caused ecological and economic damage to coastal ecosystems across the globe. While blooms of A. lagunensis had previously been confined to Texas, in 2012, an expansive brown tide occurred on Florida's East Coast, causing widespread disruption within the Indian River and Mosquito Lagoons and generating renewed interest in this organism. A major impediment to detailed investigations of A. lagunensis in an ecosystem setting has been the absence of a rapid and reliable method for cell quantification. The combination of their small size (3 to 5 μm) and nondescript extracellular features makes identification and enumeration of these cells with conventional methods a challenge. Here we report the development of an immunological-based flow cytometry method that uses a fluorescently labeled antibody developed against A. lagunensis. This method is species specific, sensitive (detection limit of 1.5 × 103 cells ml−1), precise (1% relative standard deviation of replicated samples), and accurate (108% ± 8% recovery of spiked samples) over a wide range of cell concentrations. Furthermore, this method effectively quantifies A. lagunensis in both glutaraldehyde- and formalin-preserved samples, yields a high throughput of samples (∼35 samples h−1), and is cost-effective, making it an ideal tool for managers and scientists. This method successfully documented the recurrence of a brown tide bloom in Florida in 2013. Bloom densities were highest in June (>2.0 × 106 cells ml−1) and spanned >60 km from the Ponce de Leon inlet in the northern Mosquito Lagoon south to Titusville in the Indian River Lagoon. Low levels of A. lagunensis cells were found >250 km south of this region. This method also quickly and accurately identified A. lagunensis as the causative agent of a 2013 brown tide bloom in Guantanamo Bay, Cuba, and thus should prove useful for both quantifying the dynamics of ongoing blooms of A. lagunensis as well as documenting new outbreaks of this harmful alga.
  • Preprint
    Niche of harmful alga Aureococcus anophagefferens revealed through ecogenomics
    ( 2011-01) Gobler, Christopher J. ; Berry, Dianna L. ; Dyhrman, Sonya T. ; Wilhelm, Steven W. ; Salamov, Asaf ; Lobanov, Alexei V. ; Zhang, Yan ; Collier, Jackie L. ; Wurch, Louie L. ; Kustka, Adam B. ; Dill, Brian D. ; Shah, Manesh ; VerBerkmoes, Nathan C. ; Kuo, Alan J. ; Terry, Astrid ; Pangilinan, Jasmyn ; Lindquist, Erika A. ; Lucas, Susan ; Paulsen, Ian T. ; Hattenrath-Lehmann, Theresa K. ; Talmage, Stephanie C. ; Walker, Elyse A. ; Koch, Florian ; Burson, Amanda M. ; Marcoval, Maria Alejandra ; Tang, Ying-Zhong ; LeCleir, Gary R. ; Coyne, Kathryn J. ; Berg, Gry M. ; Bertrand, Erin M. ; Saito, Mak A. ; Gladyshev, Vadim N. ; Grigoriev, Igor V.
    Harmful algal blooms (HABs) cause significant economic and ecological damage worldwide. Despite considerable efforts, a comprehensive understanding of the factors that promote these blooms has been lacking because the biochemical pathways that facilitate their dominance relative to other phytoplankton within specific environments have not been identified. Here, biogeochemical measurements demonstrated that the harmful 43 Aureococcus anophagefferens outcompeted co-occurring phytoplankton in estuaries with elevated levels of dissolved organic matter and turbidity and low levels of dissolved inorganic nitrogen. We subsequently sequenced the first HAB genome (A. anophagefferens) and compared its gene complement to those of six competing phytoplankton species identified via metaproteomics. Using an ecogenomic approach, we specifically focused on the gene sets that may facilitate dominance within the environmental conditions present during blooms. A. anophagefferens possesses a larger genome (56 mbp) and more genes involved in light harvesting, organic carbon and nitrogen utilization, and encoding selenium- and metal-requiring enzymes than competing phytoplankton. Genes for the synthesis of microbial deterrents likely permit the proliferation of this species with reduced mortality losses during blooms. Collectively, these findings suggest that anthropogenic activities resulting in elevated levels of turbidity, organic matter, and metals have opened a niche within coastal ecosystems that ideally suits the unique genetic capacity of A. anophagefferens and thus has facilitated the proliferation of this and potentially other HABs.