Chytrid infection reduces thoracic beat and heart rate of Daphnia pulicaria

Abstract

Zooplankters are hosts to numerous endoand ectoparasites, some of which have dramatic impacts on their hosts. Epizootics on zooplankton are probably more widespread in lake systems than it is currently known, and few studies have explored the direct and indirect importance of parasitism in aquatic food webs. In addition, our understanding of the sublethal effects of parasitic infections on host organisms and populations is limited. We used a novel electro-chemical based technique to measure in the outflow of the feeding current changes in the beat rate of the thoracic appendages in female Daphnia pulicaria. We observed simultaneously the heart rates and compared chytrid infected animals with uninfected gravid and non-gravid ones. We found in uninfected animals a thoracic beat rate of 3.81 ± 018 Hz and a heart rate of 4.67 ± 0.42 Hz. Gravid daphnids had a 14% lower thoracic beat rate (3.27 ± 0.30 Hz) than non-gravid females while the heart rate did not significantly differ (4.48 ± 0.28 Hz). In contrast, infected animals showed a 22% lower thoracic beat rate (2.96 ± 0.47 Hz) and a 36% lower heart rate (2.98 ± 0.5 Hz) when compared with uninfected nongravid females. We discuss the ways Daphnia are affected by Polycaryum leave infections on the individual and population level.

Protective effects of ectoine on behavioral, physiological and biochemical parameters of Daphnia magna subjected to hydrogen peroxide

“…Thoracic limbs play an important role in the process of ventilation and their movement frequency is a common physiological marker of D. magna metabolic activity and this parameter may be altered by various environmental stressors (Pirow et al, 1999;Penalva-Arana et al, 2011). The current study indicated that H 2 O 2 alone reduced thoracic limb movement probably by oxidation of cell membrane proteins and lipids of nerve and muscle cells resulting in the depressed neuromotor activity (Keller and Mattson, 1998;Aoi et al, 2004).…”

Background-free in-vivo Imaging of Vitamin C using Time-gateable Responsive Probe

“…It should be noted that no immobilization of Daphnia magna treated by TOB-Eu 3+ was observed, and the TOB-Eu 3+ treatment did not induce a significant change on the heart rate of Daphnia magna (~200 beats per minute) during the incubation 37 , which suggests that the probe is biocompatible and low-toxic for in vivo imaging of vitamin C in living bodies.…”

Protective effects of ectoine on heat-stressed Daphnia magna

“…Thoracic limb movement is a common physiological marker of Daphnia magna metabolic activity and its rate may be altered by various environmental stressors (Pirow et al, 1999a ; Penalva-Arana et al, 2011 ). Heat stress of Daphnia magna results in initial stimulation of thoracic limb activity and its subsequent decrease at sublethal temperature (Paul et al, 2004 ).…”