Impact of ocean acidification on antimicrobial activity in gills of the blue mussel (Mytilus edulis).
Here, we aimed to investigate potential effects of ocean acidification on antimicrobial peptide (AMP) activity in the gills of Mytilus edulis, as gills are directly facing seawater and the changing pH (predicted to be reduced from ∼8.1 to ∼7.7 by 2100). The AMP activity of gill and haemocyte extracts was compared at pH 6.0, 7.7 and 8.1, with a radial diffusion assay against Escherichia coli. The activity of the gill extracts was not affected by pH, while it was significantly reduced with increasing pH in the haemocyte extracts. Gill extracts were also tested against different species of Vibrio (V. parahaemolyticus, V. tubiashii, V. splendidus, V. alginolyticus) at pH 7.7 and 8.1. The metabolic activity of the bacteria decreased by ∼65-90%, depending on species of bacteria, but was, as in the radial diffusion assay, not affected by pH. The results indicated that AMPs from gills are efficient in a broad pH-range. However, when mussels were pre-exposed for pH 7.7 for four month the gill extracts presented significantly lower inhibit of bacterial growth. A full in-depth proteome investigation of gill extracts, using LC-Orbitrap MS/MS technique, showed that among previously described AMPs from haemocytes of Mytilus, myticin A was found up-regulated in response to lipopolysaccharide, 3 h post injection. Sporadic occurrence of other immune related peptides/proteins also pointed to a rapid response (0.5-3 h p.i.). Altogether, our results indicate that the gills of blue mussels constitute an important first line defence adapted to act at the pH of seawater. The antimicrobial activity of the gills is however modulated when mussels are under the pressure of ocean acidification, which may give future advantages for invading pathogens.
The Royal Swedish Academy of Sciences, Sven Lovén Center for Marine Science, Kristineberg 566, SE - 451 78 Fiskebäckskil, Sweden; Dept. of Natural Science, Kristianstad University, SE - 291 88 Kristianstad, Sweden. Electronic address: bodil.hernroth@kva.se.
B
B
Hernroth
Dept. of Biological and Environmental Sciences, University of Gothenburg, Kristineberg 566, SE - 451 78 Fiskebäckskil, Sweden.
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S
Baden
Dept. of Natural Science, Kristianstad University, SE - 291 88 Kristianstad, Sweden.
H
H
Tassidis
Dept. of Chemistry - BMC, Analytical Chemistry and SciLifeLab, Uppsala University, Box 599, SE - 75124 Uppsala, Sweden.
K
K
Hörnaeus
Dept. of Chemistry - BMC, Analytical Chemistry and SciLifeLab, Uppsala University, Box 599, SE - 75124 Uppsala, Sweden.
J
J
Guillemant
Dept. of Chemistry - BMC, Analytical Chemistry and SciLifeLab, Uppsala University, Box 599, SE - 75124 Uppsala, Sweden.
S
S
Bergström Lind
Dept. of Chemistry - BMC, Analytical Chemistry and SciLifeLab, Uppsala University, Box 599, SE - 75124 Uppsala, Sweden.
J
J
Bergquist
D000818:Animals; D023181:Antimicrobial Cationic Peptides / Q000235:genetics* / Q000378:metabolism; D057231:Climate Change; D004926:Escherichia coli / Q000502:physiology*; D005880:Gills / Q000378:metabolism / Q000382:microbiology; D006434:Hemocytes / Q000382:microbiology; D006863:Hydrogen-Ion Concentration; D049880:Mytilus edulis / Q000235:genetics* / Q000378:metabolism / Q000382:microbiology; D020543:Proteome; D012623:Seawater / Q000737:chemistry*; D014733:Vibrio / Q000502:physiology*
D023181:Antimicrobial Cationic Peptides; D020543:Proteome
Antimicrobial peptide; Gill tissue; LC-Orbitrap MS/MS analysis; LPS; Mytilus edulis; Ocean acidification; Proteome analysis; Vibrio