The effect of temperature on Pacifastacus leniusculus immunity

• Global climate change is an upcoming threat to marine as well as freshwater invertebrates andthe temperature around the globe is expected to rise with up to 4°C in the next decade. Thewater temperature is known to affect many aspects of aquatic life including immuneresponses and susceptibility to diseases. In this context, we studied the effect of temperatureon the defense system of the freshwater crayfish Pacifastacus leniusculus. Animals werechallenged with two pathogenic Gram-negative bacteria Aeromonas hydrophila andPseudomonas gessardii, as well as the bacterial cell wall component lipopolysaccharide(LPS) at two different temperatures, one cold and one room temperature. The immuneresponses were compared by means of differences in mortality, phagocytosis, bacterialclearance, and the melanization reaction of the hemolymph at these two temperatures. Weobserved that crayfish survived infections better at cold temperatures. The mortality rate waszero at 6°C following A. hydrophila or LPS injections. Furthermore, the bacteria werecompletely cleared from crayfish after they had been kept at this low temperature for morethan 9 days. We also observed a strong melanization reaction of hemolymph at 22°C whenstimulated with LPS, as well as with bacteria. Taken together, our results suggest that thecellular immunity is more effective at low temperature in this cold-adapted animal andpathogens are efficiently removed from the body by means of phagocytosis.

Ämnesord

NATURVETENSKAP  -- Biologi -- Immunologi (hsv//swe)

NATURAL SCIENCES  -- Biological Sciences -- Immunology (hsv//eng)

Nyckelord

Aeromonas hydrophila

Pseudomonas gessardii

temperature

innate immunity

melanization

invertebrate

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