Project description:Sedimentation in the sea occurs through natural processes, such as wave and tidal action, which can be exacerbated during storms and floods. Changes in terrestrial land use, marine aggregate extraction, dredging, drilling and mining are known to result in substantial sediment deposition. Research suggests that deposition will also occur due to the modern development of marine renewable energy. The response to individual burial under three depths of sediment, three sediment fractions and five burial durations was investigated in two mussel species, Modiolus modiolus and Mytilus edulis in specialist mesocosms. Both mussel species showed substantial mortality, which increased with duration of burial and burial by finer sediment fractions. M. modiolus was better able to survive short periods of burial than M. edulis, but at longer durations mortality was more pronounced. No mortality was observed in M. modiolus in burial durations of eight days or less but by 16 days of burial, over 50% cumulative mortality occurred. Under variable temperature regimes, M. edulis mortality increased from 20% at 8°C to over 60% at 14.5 and 20°C. Only M. edulis was able to emerge from burial, facilitated by increased byssus production, laid mostly on vertical surfaces but also on sediment particles. Emergence was higher from coarse sediment and shallow burials. Byssus production in M. edulis was not related to the condition index of the mussels. Results suggest that even marginal burial would result in mortality and be more pronounced in warm summer periods. Our results suggest that in the event of burial, adult M. modiolus would not be able to emerge from burial unless local hydrodynamics assist, whereas a small proportion of M. edulis may regain contact with the sediment water interface. The physiological stress resulting in mortality, contribution of local hydrodynamics to survival and other ecological pressures such as mussels existing in aggregations, are discussed.
Project description:C1q domain-containing (C1qDC) proteins are a group of biopolymers involved in immune response as pattern recognition receptors (PRRs) in a lectin manner identifying and binding carbohydrate components of pathogen-associated molecular patterns (PAMPs). In the current study, we present a new protein MkC1qDC-1 purified from the hemolymph plasma of Modiolus kurilensis bivalve mollusk widespread in the Northwest Pacific. The isolation procedure included ammonium sulfate precipitation followed by affinity chromatography on pectin-Sepharose. The full-length MkC1qDC-1 sequence was assembled based on mass-spectrometry data supplemented with N-terminal Edman sequencing, and included 156 amino acid residues displaying high homology to C1qDC proteins of bivalves. 2-D electrophoresis of purified MkC1qDC-1 showed a single polypeptide with 19 kDa mass and pI 5.2 in accordance with predicted values. The protein was functionally active after 1 h incubation in temperatures up to 50°C and stable over a wide pH range. MkC1qDC-1 demonstrated antibacterial properties against gram-negative and gram-positive strains.