title: Correlative light/electron microscopy for the investigation of microbial mats from Black Sea Cold Seeps.
abstract: In several fields of cell biology, correlative microscopy is applied to compare the structure of objects at high resolution under the electron microscope with low resolution light microscopy images of the same sample. It is, however, difficult to prepare samples and marker systems that are applicable for both microscopic techniques for the same specimen at the same time. In our studies, we used microbial mats from Cold Seep communities for a simple and rapid correlative microscopy method. The mats consist of bacterial and archaeal microorganisms, coupling reverse methanogenesis to the reduction of sulfate. The reverse methanogenic pathway also generates carbonates that precipitate inside the mat and may be the main reason for the formation of a microbial reef. The mat shows highly differentiated aggregates of various organisms, tightly interconnected by extracellular polysaccharides. In order to investigate the role of EPS as adhesive mucilage for the biofilm and as a precipitation matrix for carbonate minerals, samples were embedded in a hydrophilic resin (Lowicryl K4 M). Sections were suitable for light as well as electron microscopy in combination with lectins, either labeled with a fluorescent marker or with colloidal gold. This allows lectin mapping at low resolution for light microscopy in direct comparison with a highly resolved electron microscopic image.
authors.affiliation: Institut für Mikrobiologie und Genetik der Universität Göttingen, Grisebachstr. 8, D-37077 Göttingen, Germany.
authors.forename: Christoph
authors.initials: C
authors.lastname: Wrede
authors.forename: Christina
authors.initials: C
authors.lastname: Heller
authors.forename: Joachim
authors.initials: J
authors.lastname: Reitner
authors.forename: Michael
authors.initials: M
authors.lastname: Hoppert
mesh_terms: D001105:Archaea / Q000378:metabolism / Q000648:ultrastructure*; D001419:Bacteria / Q000378:metabolism / Q000648:ultrastructure*; D002254:Carbonates / Q000378:metabolism; D003080:Cold Temperature; D005456:Fluorescent Dyes; D019015:Geologic Sediments / Q000382:microbiology*; D017979:Gold Colloid; D037102:Lectins / Q000378:metabolism; D008697:Methane / Q000096:biosynthesis; D008853:Microscopy; D008854:Microscopy, Electron; D008867:Microtomy; D010084:Oxidation-Reduction; D016613:Plastic Embedding; D011134:Polysaccharides / Q000378:metabolism; D011135:Polysaccharides, Bacterial / Q000378:metabolism; D012623:Seawater / Q000382:microbiology*; D013194:Staining and Labeling / Q000379:methods; D013431:Sulfates / Q000378:metabolism
chemical_list: D002254:Carbonates; D005456:Fluorescent Dyes; D017979:Gold Colloid; D037102:Lectins; D011134:Polysaccharides; D011135:Polysaccharides, Bacterial; D013431:Sulfates; D008697:Methane