Calcium Metabolism in a Freshwater Mollusc : Quantitative Importance of Water and Food as Supply for Calcium During Growth

Borght, O. Van Der; Puymbroeck, S. Van

doi:10.1038/210791a0

Cited by 59 publications

(18 citation statements)

References 13 publications

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“…Here we provide the first direct evidence that this is indeed the case. Lymnaea stagnalis is a calciphile, obtaining at least 80% of its calcium requirements directly from the water (Van Der Borght and Van Puymbroek, 1966). Its distribution is limited by environmental calcium availability, with populations requiring a minimum of 20mgl -1 environmental calcium (Boycott, 1936;Young, 1975), and, at low levels of environmental calcium, growth and reproduction decline (McKillop and Harrison, 1972).…”

Section: Discussionmentioning

confidence: 99%

Sensory mediation of memory blocking stressors in the pond snailLymnaea stagnalis

Dalesman

Karnik

Lukowiak

2011

Journal of Experimental Biology

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to external chemical stimulation (Wedemeyer and Schild, 1995;Kamardin et al., 2001), it is thought to be responsible for analysing many of the physiochemical properties of the water in which the snail lives. Despite this knowledge, very little is known about how sensory input from the osphradium affects the behaviour of the snail in response to changes in the environment. A recent study demonstrated that the osphradium is used to sense the presence of predator kairomones from a crayfish (Il-Han et al., 2010). The presence of crayfish kairomones during operant conditioning of aerial respiratory behaviour enhances long-term memory (LTM) formation in L. stagnalis . By severing the osphradial nerve innervating the central nervous system (CNS), the snails no longer responded to the presence of crayfish kairomones in their environment, and responded to the training regime in the Accepted 9 May 2011 SUMMARY The great pond snail, Lymnaea stagnalis, is commonly used as a model species to study how stress affects the ability to form long-term memory (LTM); however, we still have little information about how the snail senses stressful stimuli. The osphradium is an external sensory organ that demonstrates electrophysiological responses to a variety of external chemical stimuli. We examined the role, if any, played by the osphradium in sensing two environmental stressors, crowding and low environmental calcium, both known to block LTM in intact animals. We severed the osphradial nerve, blocking external sensory input from this organ to the central nervous system, and then exposed the snails to low environmental calcium or crowding stress to assess whether these stressors continued to block LTM formation. When exposed to low environmental calcium, snails with their osphradial nerve severed responded as if they were maintained in our standard calcium environment. That is, they did not respond to low calcium as a stressor blocking LTM; therefore, the osphradium plays a crucial role in mediating how snails respond to this stressor. However, following crowding, LTM formation was blocked in both control groups and snails that had the osphradial nerve severed, indicating that sensory information from the osphradium is not required to sense crowded conditions. Together these data show that two stressors that result in the same behavioural phenotype, blocking LTM formation, do so via two distinct sensory pathways.

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Section: Discussionmentioning

confidence: 99%

Sensory mediation of memory blocking stressors in the pond snailLymnaea stagnalis

Dalesman

Karnik

Lukowiak

2011

Journal of Experimental Biology

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“…Romaine lettuce has been used as a food source to successfully rear snails at this facility for several years, and although it contains a source of calcium that the snails would be able to utilize, the calcium content is fairly low (0.36 mg Ca 2+ per gram of lettuce). Previous work has suggested that Lymnaea obtains the majority of its calcium requirements from the water (Van Der Borght and Van Puymbroek, 1966 (20 mg l -1 ) depending on the treatment group for 1 week prior to training. Operant conditioning to reduce aerial respiration in hypoxic conditions was carried out using a training procedure consisting of two 0.5 h training sessions separated by 1 h (Sangha et al, 2003b;Parvez et al, 2005).…”

Section: Methodsmentioning

confidence: 99%

“…For calciphilic species, including the great pond snail, Lymnaea stagnalis, environmental calcium is a major factor limiting distribution, with populations absent from environments containing less than 20 mg l -1 Ca 2+ (Boycott, 1936;Macan, 1977;Briers, 2003). Lymnaea relies on dissolved calcium in the water to provide 80% of its calcium requirements, with the remainder coming from food sources (Van Der Borght and Van Puymbroek, 1966), and whilst Lymnaea populations are able to survive in 20 mg l -1 Ca 2+ , they are unable to demonstrate shell thickening, which provides protection from predators (Rundle et al, 2004). Where environmental calcium is limited (less than 50 mg l -1 ), there are metabolic costs associated with Ca 2+ uptake from the environment into the snail to maintain internal Ca 2+ homeostasis, and these costs are greatly reduced at the 80mgl -1 level (Greenaway, 1971).…”

Section: Introductionmentioning

confidence: 99%

Low external environmental calcium levels prevent forgetting in Lymnaea

Knezevic

Dalesman

Karnik

et al. 2011

Journal of Experimental Biology

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SUMMARYForgetting may allow an animal to react more appropriately to current conditions, rather than continuing to exhibit a previously learned, possibly maladaptive behaviour based on previous experience. One theory is that forgetting is an active process, whereby the previously learnt response is replaced by new learning that interferes with the older memory. Hence, we hypothesized that an appropriately timed environmental stressor that blocks long-term memory ( ) immediately following training, they retained memory for at least 96 h, indicating that forgetting had been blocked. Thus, when exposed to low environmental Ca 2+ , Lymnaea will fail to form new memories, but will also continue to retain information previously learned and remembered as the low calcium blocks forgetting.

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“…The snails were fed butterhead lettuce for 5 days per week. Fish food pellets (Velda, Gold Sticks Basic Food) were supplied once a week to provide other nutrients, and half a piece of chalkboard chalk was supplied to provide calcium as the concentration of calcium in the ground water (36 mg L -1 ) may be low for the calciphile species L. stagnalis (Van der Borght & Van Puymbroeck, 1966;Dalesman & Lukowiak, 2010). The water used to culture the snails was fully replaced once, and halfway through the culturing period several indicators of water quality were checked with a multi-meter (Multi 350i/SET, Germany).…”

Section: Model Systemmentioning

confidence: 99%

The effect of temperature on herbivory by the omnivorous ectotherm snail Lymnaea stagnalis

et al. 2016

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Rising temperatures likely affect the trophic interactions in temperate regions as global warming progresses. An open question is how a temperature rise may affect consumer pressure and plant abundance in shallow aquatic ecosystems, where most consumers are omnivorous. Interestingly, herbivory (plant-eating) is more prevalent toward low latitudes in ectotherms such as fish and aquatic invertebrates, and this may be temperature driven. We used pond snails (Lymnaea stagnalis L.) as a model aquatic ectotherm species and tested their consumption of both animal prey (Gammarus pulex L.) and plant material (Potamogeton lucens L.) at three different temperatures (15, 20, and 25°C). Higher temperatures led to higher consumption rates by the omnivore on both plant food and animal prey when fed separately. When the food was offered simultaneously, the pond snails consistently preferred animal prey over plant material at all tested temperatures. However, the omnivore did consume plant material even though they had enough animal prey available to them. Based on our experiments, we conclude that with increasing temperatures, L. stagnalis will only increase their consumption rates but not change food preference. Further studies are needed to test the generality of our findings across aquatic species to predict the effect of warming on aquatic plant consumption.

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Calcium Metabolism in a Freshwater Mollusc : Quantitative Importance of Water and Food as Supply for Calcium During Growth

Cited by 59 publications

References 13 publications

Sensory mediation of memory blocking stressors in the pond snailLymnaea stagnalis

Sensory mediation of memory blocking stressors in the pond snailLymnaea stagnalis

Low external environmental calcium levels prevent forgetting in Lymnaea

The effect of temperature on herbivory by the omnivorous ectotherm snail Lymnaea stagnalis

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