The physiological response of the marine platyhelminthMacrostomum lignanoto different environmental oxygen concentrations

Abstract

SUMMARYThe respiration rate of meiofauna is difficult to measure, and the response to variations in the environmental oxygen concentration has so far been mainly addressed through behavioral investigation. We investigated the effect of different oxygen concentrations on the physiology of the marine platyhelminth Macrostomum lignano. Respiration was measured using batches of 20 animals in a glass microtiter plate equipped with optical oxygen sensor spots. At higher oxygen saturations (>12kPa), the animals showed a clear oxyconforming behavior. However, below this value, the flatworms kept respiration rates constant at 0.064±0.001nmol O 2 l ) -showed increased ROS formation following anoxia-reoxygenation treatment. Animals exposed to hyperoxic, normoxic and anoxic treatments displayed no significant differences in O 2 • -formation, whereas mitochondrial ROS formation as detected by C-H 2 DFFDA was higher after hyperoxic exposure and lowest under near-anoxia conditions compared with the normoxic control group. Macrostomum lignano seems to be a species that is tolerant of a wide range of oxygen concentrations (being able to maintain aerobic metabolism from extremely low P O2 up to hyperoxic conditions), which is an essential prerequisite for successfully dealing with the drastic environmental oxygen variations that occur within intertidal sediments. Supplementary material available online at

A screening-based platform for the assessment of cellular respiration in Caenorhabditis elegans

“…As the experimental set-up only requires organisms that are viable in liquid culture and have a size that fits the transient microchamber (XF96: 3 μl, XF24: 7 μl), mitochondrial respiration can also be estimated in species other than C. elegans. Therefore, Seahorse XF respirometers might open new avenues for other well-established or upcoming species that may be used in metabolic or aging studies, such as the flatworm Macrostomum lignano 56, Danio Rerio embryos57–58 and even Nothobranchius furzeri embryos59. While XF respirometers are, to our knowledge, not used in Macrostomum lignano or Nothobranchius furzeri research yet, it has been shown that respiratory kinetics in embryos from Danio Rerio can be investigated with XF respirometers58.…”

Preparation for oxidative stress under hypoxia and metabolic depression: Revisiting the proposal two decades later

“…The few works that had measured ROS levels using chemical probes indicate that indeed ROS formation still occurs during oxygen deprivation (even in animals under anoxia) (Milton et al, 2007;Rivera-Ingraham et al, 2013a;RiveraIngraham et al, 2013b), but, so far, there is no report of increased ROS in such situations. On the other hand, there are many pieces of indirect evidence that indicates that ROS levels should rise.…”

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CO2-induced fertilization impairment in Strongylocentrotus droebachiensis collected in the Arctic

“…ASW was continuously aerated with humidified filtered air (0.2 lm) of different partial pressures of CO 2 in 5-l Duran borosilicate bottles equipped with glass frits. This manipulation method is the most appropriate to reproduce the expected situation influenced by atmospheric CO 2 concentrations (Riebesell et al 2010).…”

“…The CO 2 partial pressures were selected according to the literature (Riebesell et al 2010;IPCC-Report 2007) to represent atmospheric conditions during the last glacial maximum and the present conditions (measured pCO 2 between 180-425 latm), projected acidification scenarios by the end of the century and increased/extreme values (acidified conditions with measured pCO 2 *550-800, *1,300 and *2,000 latm).…”