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Effects of the acanthocephalan Polymorphus minutus and the microsporidian Dictyocoela duebenum on energy reserves and stress response of cadmium exposed Gammarus fossarum.

Chen HY, Grabner DS, Nachev M, Shih HH, Sures B - PeerJ (2015)

Bottom Line: An increase of glycogen was also found due to interaction of acanthocephalan and microsporidian infection.P. minutus did not affect the stress response of its host.The results of our study clearly demonstrate the importance of parasitic infections, especially of microsporidians, for ecotoxicological research.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Life Science, National Taiwan University , Taipei , Taiwan ; Aquatic Ecology and Centre for Water and Environmental Research, University of Duisburg-Essen , Essen , Germany.

ABSTRACT
Amphipods are commonly parasitized by acanthocephalans and microsporidians and co-infections are found frequently. Both groups of parasites are known to have severe effects on their host. For example, microsporidians can modify host sex ratio and acanthocephalans can manipulate the behavior of the amphipod to promote transmission to the final host. These effects influence host metabolism in general and will also affect the ability of amphipods to cope with additional stressors such as environmental pollution, e.g., by toxic metals. Here we tested the effects of sub-lethal concentrations of cadmium on glycogen and lipid levels, as well as on the 70kDa heat shock protein (hsp70) response of field collected Gammarus fossarum, which were naturally infected with microsporidians and the acanthocephalan Polymorphus minutus. Infected and uninfected G. fossarum were exposed to a nominal Cd concentration of 4 µg/L, which resembled measured aqueous Cd concentration of 2.9 µg/L in reconstituted water for 7 d at 15 °C in parallel to an unexposed control. After exposure gammarids were snap frozen, weighed, sexed and tested for microsporidian infection by PCR. Only individuals containing the microsporidian Dictyocoela duebenum were used for the further biochemical and metal analyses. P. minutus infected amphipods were significantly smaller than their uninfected conspecifics. Mortality was insignificantly increased due to cadmium exposure, but not due to parasite infection. Microsporidian infection in combination with cadmium exposure led to increased glycogen levels in female gammarids. An increase of glycogen was also found due to interaction of acanthocephalan and microsporidian infection. Elevated lipid levels were observed in all groups infected with microsporidians, while acanthocephalans had the opposite effect. A positive correlation of lipid and glycogen levels was observed. The general stress response measured in form of hsp70 was significantly increased in microsporidian infected gammarids exposed to cadmium. P. minutus did not affect the stress response of its host. Lipid levels were correlated negatively with hsp70 response, and indicated a possible increased stress susceptibility of individuals with depleted energy reserves. The results of our study clearly demonstrate the importance of parasitic infections, especially of microsporidians, for ecotoxicological research.

No MeSH data available.


Related in: MedlinePlus

Box plot of gammarid weight depending on infection and sex.Numbers below boxes show number of gammarids. Asterisks indicate significant differences.
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fig-3: Box plot of gammarid weight depending on infection and sex.Numbers below boxes show number of gammarids. Asterisks indicate significant differences.

Mentions: The mean weight of females (19.96 mg) and males (25.63 mg) differed significantly (Welch two sample t-test; t = − 5.18, p < 0.001; (Fig. 3). Additionally, acanthocephalan infected gammarids had a significantly lower weight than their uninfected conspecifics (females: infected 18.84 mg vs 20.47 mg for uninfected gammarids, F = 5.90, p < 0.05; males: infected 22.94 mg vs uninfected 28.70 mg for uninfected gammarids, F = 11.07, p < 0.01). In contrast, microsporidian infection was not correlated with the weight of gammarids (females: F = 0.01, p = 0.92; males: F = 0.27, p = 0.61; Fig. 3).


Effects of the acanthocephalan Polymorphus minutus and the microsporidian Dictyocoela duebenum on energy reserves and stress response of cadmium exposed Gammarus fossarum.

Chen HY, Grabner DS, Nachev M, Shih HH, Sures B - PeerJ (2015)

Box plot of gammarid weight depending on infection and sex.Numbers below boxes show number of gammarids. Asterisks indicate significant differences.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4631464&req=5

fig-3: Box plot of gammarid weight depending on infection and sex.Numbers below boxes show number of gammarids. Asterisks indicate significant differences.
Mentions: The mean weight of females (19.96 mg) and males (25.63 mg) differed significantly (Welch two sample t-test; t = − 5.18, p < 0.001; (Fig. 3). Additionally, acanthocephalan infected gammarids had a significantly lower weight than their uninfected conspecifics (females: infected 18.84 mg vs 20.47 mg for uninfected gammarids, F = 5.90, p < 0.05; males: infected 22.94 mg vs uninfected 28.70 mg for uninfected gammarids, F = 11.07, p < 0.01). In contrast, microsporidian infection was not correlated with the weight of gammarids (females: F = 0.01, p = 0.92; males: F = 0.27, p = 0.61; Fig. 3).

Bottom Line: An increase of glycogen was also found due to interaction of acanthocephalan and microsporidian infection.P. minutus did not affect the stress response of its host.The results of our study clearly demonstrate the importance of parasitic infections, especially of microsporidians, for ecotoxicological research.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Life Science, National Taiwan University , Taipei , Taiwan ; Aquatic Ecology and Centre for Water and Environmental Research, University of Duisburg-Essen , Essen , Germany.

ABSTRACT
Amphipods are commonly parasitized by acanthocephalans and microsporidians and co-infections are found frequently. Both groups of parasites are known to have severe effects on their host. For example, microsporidians can modify host sex ratio and acanthocephalans can manipulate the behavior of the amphipod to promote transmission to the final host. These effects influence host metabolism in general and will also affect the ability of amphipods to cope with additional stressors such as environmental pollution, e.g., by toxic metals. Here we tested the effects of sub-lethal concentrations of cadmium on glycogen and lipid levels, as well as on the 70kDa heat shock protein (hsp70) response of field collected Gammarus fossarum, which were naturally infected with microsporidians and the acanthocephalan Polymorphus minutus. Infected and uninfected G. fossarum were exposed to a nominal Cd concentration of 4 µg/L, which resembled measured aqueous Cd concentration of 2.9 µg/L in reconstituted water for 7 d at 15 °C in parallel to an unexposed control. After exposure gammarids were snap frozen, weighed, sexed and tested for microsporidian infection by PCR. Only individuals containing the microsporidian Dictyocoela duebenum were used for the further biochemical and metal analyses. P. minutus infected amphipods were significantly smaller than their uninfected conspecifics. Mortality was insignificantly increased due to cadmium exposure, but not due to parasite infection. Microsporidian infection in combination with cadmium exposure led to increased glycogen levels in female gammarids. An increase of glycogen was also found due to interaction of acanthocephalan and microsporidian infection. Elevated lipid levels were observed in all groups infected with microsporidians, while acanthocephalans had the opposite effect. A positive correlation of lipid and glycogen levels was observed. The general stress response measured in form of hsp70 was significantly increased in microsporidian infected gammarids exposed to cadmium. P. minutus did not affect the stress response of its host. Lipid levels were correlated negatively with hsp70 response, and indicated a possible increased stress susceptibility of individuals with depleted energy reserves. The results of our study clearly demonstrate the importance of parasitic infections, especially of microsporidians, for ecotoxicological research.

No MeSH data available.


Related in: MedlinePlus