Intracellular Oceanospirillales bacteria inhabit gills of Acesta bivalves

Abstract

A novel bacterium was discovered in the gills of the large bivalve Acesta excavata (Limidae) from coral reefs on the northeast Atlantic margin near the shelf break of the fishing ground Haltenbanken of Norway, and confirmed present in A. excavata from a rock-wall in the Trondheimsfjord. Purified gill DNA contained one dominant bacterial rRNA operon as indicated from analysis of broad range bacterial PCR amplicons in denaturant gradient gels, in clone libraries and by direct sequencing. The sequences originated from an unknown member of the order Oceanospirillales and its 16S rRNA gene fell within a clade of strictly marine invertebrate-associated Gammaproteobacteria. Visual inspection by fluorescent in situ hybridization and transmission electron microscopy indicated a pleomorphic bacterium with no visible cell wall, located in aggregates inside vacuoles scattered within the gill cells cytoplasm. Intracellular Oceanospirillales exist in bathymodiolin mussels (parasites), Osedax worms and whiteflies (symbionts). This bacterium apparently lives in a specific association with the Acesta.

Bacteria of the genus Endozoicomonas dominate the microbiome of the Mediterranean gorgonian coral Eunicella cavolini

“…The group of samples from 30 m contained an Endozoicomonas OTU that was not found among the other gorgonians, and the samples from 41 m were associated with one OTU that could not be assigned in the SILVA taxonomy database. However, none of these G24A G24B G24C G30A G30B G30C G41A G41B G41C OTU1 7 148 10 35 78 97 4 9 4 392 0.57 OTU2 24 157 18 56 78 148 9 2 2 494 0.72 OTU3 1311 11662 1355 7492 4187 3435 9330 1998 1519 42289 61.35 OTU41 61 48 150 419 17 83 20 2 48 Oceanospirillales and the family Hahellaceae, and most bacteria closely related to them are associated with marine invertebrates (Zielinski et al 2009, Jensen et al 2010. The closest relatives in the database were isolated from a Caribbean gorgonian, Gorgonia ventalina (98.3% identity) (Sunagawa et al 2010) and the arctic gorgonian Alcyonium ant arcticum (93.3% identity) (Webster & Bourne 2007).…”

“…S3 in the Supplement). Endozoicomonas have been found in sponges (some under the name Spongiobacter) (Thiel et al 2007, Mohamed et al 2008, Nishijima et al 2013, bivalves (Zielinski et al 2009, Jensen et al 2010, ascidians (Martínez-García et al 2007), a nudibranch (Kurahashi & Yokota 2007), polychaetes (Goffredi et al 2007), sea anemones (Schuett et al 2007, Du et al 2010, starfish (Choi et al 2010), scleractinian corals (Bourne & Munn 2005, Bourne et al 2008, Hansson et al 2009, Littman et al 2009, Raina et al 2009, Sunagawa et al 2010, Speck & Donachie 2012, and different tropical gorgonians and other soft corals (Webster & Bourne 2007, Sunagawa et al 2010). In the Caribbean gorgonian Gorgonia ventalina, the most common bacteria are Endozoicomonas.…”

Methane and minor oil macro-seep systems — Their complexity and environmental significance

“…But, the intensified study of microorganisms in the water and sediments surrounding and beneath such reefs, demonstrates the presence of seep-related microorganisms in their immediate surroundings (Jensen et al, 2008a(Jensen et al, , 2008b(Jensen et al, , 2010. They seem to be 'bathing' in nutrient rich water containing similar primary producers as those observed blooming in the Deepwater Horizon blowout plume, mentioned previously.…”

“…In June, plume samples were dominated by two different bacterial groups of Gammaproteobacteria, Colwellia, and Cycloclasticus . Another remarkable aspect, is that although these bacterial species are rare in normal seawater, three of the groups: Oceanospirillales, Gammaproteobacteria, and Colwellia are found in seawater sampled from deep-water coral reefs occurring at Norwegian oil and gas fields off mid Norway (Hovland, 2008;Jensen et al, 2008aJensen et al, , 2008bJensen et al, 2010). This probably means that the corals living in total darkness off Norway (and also several places in the GoM), may actually derive part of their nutrients from primary producers feeding on hydrocarbons originating from nearby natural seeps (Hovland, 1990;Hovland and Thomsen, 1997;Hovland and Risk, 2003).…”

Horizontal gene transfer in the sponge Amphimedon queenslandica

“…Intranuclear bacteria can be stable over long periods of time in protozoa, dinoflagellates, free-living amoebae, and arthropods (Grandi et al 1997;Görtz 2001;Alverca et al 2002;Fujishima and Kodama 2012;Schulz et al 2014), but they can also be detrimental to host cells in protozoa, euglenoids, freeliving amoebae, and marine invertebrates by ultimately causing lysis (Roth 1957;Leedale 1969;Elston 1986;Azevedo 1989;Görtz 2001;Zielinski et al 2009;Jensen et al 2010). Intranuclear bacteria have also been observed in the marine sponge Aplysina cavernicola, though have not been further characterised (Friedrich et al 1999), and while thought rare, nuclei have been invaded by bacteria in mammalian cells in vitro (Burgdorfer et al 1968;Urakami et al 1982;Pongponratn et al 1998;Ogata et al 2006).…”