scholarly journals Input from a chemosensory organ, the osphradium, does not mediate aerial respiration in Lymnaea stagnalis

2012 ◽  
Vol 15 (2) ◽  
pp. 167-173 ◽  
Author(s):  
V Karnik ◽  
S Dalesman ◽  
K Lukowiak
Keyword(s):  
Lymnaea Stagnalis ◽  
Aerial Respiration

Memory from one-trial training is resistant to extinction in Lymnaea Stagnaliss

2007 ◽  
Vol 30 (4) ◽  
pp. 89
Author(s):  
Kara Murias ◽  
Martin Amarell ◽  
Ken Lukowiak
Keyword(s):  
Lymnaea Stagnalis ◽  
Aversive Stimulus ◽  
Traumatic Event ◽  
Training Stimulus ◽  
Extinction Training ◽  
Long Term Memory ◽  
Training Environment ◽  
Aerial Respiration ◽  
Extreme Stress ◽  
Water Pond

Background: Memories that follow a traumatic event or extreme stress have been shown in some cases, to be particularly resistant to therapies meant to reduce their impact on patients. Two methods shown to decrease memories in laboratory tests are disruption after reactivation and extinction training. Newly formed memories undergo a period of stabilization, during which they are susceptible to amnesia treatments. Over a period of time memories become stabilized and can no longer be disrupted. However memories that are retrieved are returned to a labile state that must undergo a process of ‘reconsolidation’. Also, many memories can be occluded by ‘extinction training’, which consists of withholding the training stimulus in the training environment resulting in a new memory that overshadows the original training. Methods and Results: Using the Lymnaea stagnalis model system we show that memories following an extreme aversive stimulus demonstrate resistance to manipulation by these methods. Lymnaea stagnalis are fresh-water pond snails that can breathe either cutaneously or aerially through an orifice (pneumostome). Snails can form a long-term memory (LTM) to suppress pneumostome opening after operant conditioning consisting of either multiple sessions of repeated tactile stimulation to the orifice area each time the snail attempts to open its pneumostome or a single applications of 25mM KCl stimulus contingent with pneumostome opening (one-trial training; 1TT). The LTM formed following one-trial training has many of the same characteristics as memory formed following repetitive tactile training. Specifically, both are dependent on new mRNA synthesis in the circuit that controls aerial respiration and both can be blocked by cooling immediately after training. However, we show that memories in Lymnaea that form after a single, highly aversive stimulus, unlike LTM after repetitive training, aren’t disrupted after reactivation. We also attempted to extinguish the 1TT memory by placing the snails in the training beaker and not applying the KCl stimulus when they opened their pneumostome. When repetitive training was employed, extinction sessions such as these resulted in naïve levels of aerial respiration i.e. occlusion of the operantly trained memory. Conclusions: Therefore, memory after 1TT is more resistant to suppression by extinction training than memories formed after less aversive stimuli. Further research will attempt to determine the cellular mechanism that causes the memory to be particularly resilient.

A thermal stressor, propranolol and LTM formation in freshly collected Lymnaea

2021 ◽  
Author(s):  
Cayley Swinton ◽  
Erin Swinton ◽  
Iain Phillips ◽  
Ken Lukowiak
Keyword(s):  
Operant Conditioning ◽  
Lymnaea Stagnalis ◽  
Test Session ◽  
Long Term Memory ◽  
Memory Recall ◽  
Term Memory ◽  
Aerial Respiration ◽  
Cognitive Phenotype ◽  
Heat Stressor

A heat stressor (1h at 30o C) in Lymnaea stagnalis before operant conditioning training of aerial respiration is sufficient to enhance long-term memory (LTM) formation in average cognitive-ability, laboratory-reared, inbred snails. However, in freshly collected outbred snails the same heat stressor blocks LTM formation in smart cognitive phenotype but not in average cognitive phenotype strains. Here we hypothesize that: 1) preventing the stress associated with the heat stressor before training allows LTM to form in the smart phenotype strains ; and 2) alleviating the stress before a memory recall session allows a formed LTM to be recalled in the smart phenotype strains. We found that an injection of propranolol, which mitigates the stressor, before snails experience the heat stressor enabled two strains of the smart phenotype snails to form LTM formation, consistent with our first hypothesis. However, the injection of propranolol before a memory test session, did not alleviate a memory recall block in the smart phenotype snails. Thus, our second hypothesis was not supported. Thus, smart cognitive phenotype snails encountering a heat stressor have an inability to form LTM, but this inability can be overcome by the pre-injection of propranolol.

The First Record of Parthenitae and Cercariae of Plagiorchis Multiglandularis (Trematoda, Plagiorchiidae) in Lymnaea Stagnalis in Ukraine

2018 ◽  
Vol 52 (4) ◽  
pp. 289-294
Author(s):  
E. P. Zhytova
Keyword(s):  
Lymnaea Stagnalis ◽  
Morphological Characteristics ◽  
First Record ◽  
Morphometric Data ◽  
Diagnostic Characters ◽  
Plagiorchis Elegans

Abstract Parthenitae and cercariae of Plagiorchis. multiglandularis Semenov, 1927 are recorded in Lymnaea stagnalis (Linnaeus, 1758) for the fi rst time in Ukraine; their morphological characteristics are specifi ed. Diagnostic characters of P. multiglandularis parthenitae and cercariae found in Ukrainian Polissia are compared with those from other regions. To confi rm the validity of the species, a comparison of the morphometric data of this trematode larvae with the cercariae of Plagiorchis elegans (Rudolphi, 1802) Braun, 1902, found in molluscs L. stagnalis, L. ralustris and L. corvuses, was performed. It was determined that P. multiglandularis cercariae diff er from those of P. elegans in size and position of the penetration glands.

Analysis and modulation of spike trains and oscillations in identified neural network of Lymnaea stagnalis L

2000 ◽  
Vol 51 (2-4) ◽  
pp. 231-235
Author(s):  
G. Molnár ◽  
A. Szűcs ◽  
Katalin S. Rózsa
Keyword(s):  
Neural Network ◽  
Lymnaea Stagnalis ◽  
Spike Trains

scholarly journals Transcriptome profiling of Lymnaea stagnalis (Gastropoda) for ecoimmunological research

BMC Genomics ◽  
2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Otto Seppälä ◽  
Jean-Claude Walser ◽  
Teo Cereghetti ◽  
Katri Seppälä ◽  
Tiina Salo ◽  
...  
Keyword(s):  
Environmental Conditions ◽  
Individual Variation ◽  
Lymnaea Stagnalis ◽  
De Novo ◽  
Transcriptome Profiling ◽  
Snail Species ◽  
Immune Defence ◽  
Immune Activity ◽  
Self Recognition ◽  
Immune Assays

Abstract Background Host immune function can contribute to numerous ecological/evolutionary processes. Ecoimmunological studies, however, typically use one/few phenotypic immune assays and thus do not consider the complexity of the immune system. Therefore, “omics” resources that allow quantifying immune activity across multiple pathways are needed for ecoimmunological models. We applied short-read based RNAseq (Illumina NextSeq 500, PE-81) to characterise transcriptome profiles of Lymnaea stagnalis (Gastropoda), a multipurpose model snail species. We used a genetically diverse snail stock and exposed individuals to immune elicitors (injury, bacterial/trematode pathogens) and changes in environmental conditions that can alter immune activity (temperature, food availability). Results Immune defence factors identified in the de novo assembly covered elements broadly described in other gastropods. For instance, pathogen-recognition receptors (PRR) and lectins activate Toll-like receptor (TLR) pathway and cytokines that regulate cellular and humoral defences. Surprisingly, only modest diversity of antimicrobial peptides and fibrinogen related proteins were detected when compared with other taxa. Additionally, multiple defence factors that may contribute to the phenotypic immune assays used to quantify antibacterial activity and phenoloxidase (PO)/melanisation-type reaction in this species were found. Experimental treatments revealed factors from non-self recognition (lectins) and signalling (TLR pathway, cytokines) to effectors (e.g., antibacterial proteins, PO enzymes) whose transcription depended on immune stimuli and environmental conditions, as well as components of snail physiology/metabolism that may drive these effects. Interestingly, the transcription of many factors (e.g., PRR, lectins, cytokines, PO enzymes, antibacterial proteins) showed high among-individual variation. Conclusions Our results indicate several uniform aspects of gastropod immunity, but also apparent differences between L. stagnalis and some previously examined taxa. Interestingly, in addition to immune defence factors that responded to immune elicitors and changes in environmental conditions, many factors showed high among-individual variation across experimental snails. We propose that such factors are highly important to be included in future ecoimmunological studies because they may be the key determinants of differences in parasite resistance among individuals both within and between natural snail populations.

scholarly journals A survey of miRNAs involved in biomineralization and shell repair in the freshwater gastropod Lymnaea stagnalis

2021 ◽  
Vol 1 (1) ◽  
Author(s):  
Nicolas Cerveau ◽  
Daniel John Jackson
Keyword(s):  
Matrix Protein ◽  
Lymnaea Stagnalis ◽  
Sequence Similarity ◽  
Mature Mirnas ◽  
Pond Snail ◽  
Mrna Levels ◽  
Forming Process ◽  
Rna Molecules ◽  
Freshwater Gastropod ◽  
Shell Matrix

AbstractMicroRNAs (miRNAs) are a deeply conserved class of small, single stranded RNA molecules that post-transcriptionally regulate mRNA levels via several targeted degradation pathways. They are involved in a wide variety of biological processes and have been used to infer the deep evolutionary relationships of major groups such as the Metazoa. Here we have surveyed several adult tissues of the freshwater pulmonate Lymnaea stagnalis (the Great Pond Snail) for miRNAs. In addition we perform a shell regeneration assay to identify miRNAs that may be involved in regulating mRNAs directly involved in the shell-forming process. From seven mature tissues we identify a total of 370 unique precursor miRNAs that give rise to 336 unique mature miRNAs. While the majority of these appear to be evolutionarily novel, most of the 70 most highly expressed (which account for 99.8% of all reads) share sequence similarity with a miRBase or mirGeneDB2.0 entry. We also identify 10 miRNAs that are differentially regulated in mantle tissue that is actively regenerating shell material, 5 of which appear to be evolutionarily novel and none of which share similarity with any miRNA previously reported to regulate biomineralization in molluscs. One significantly down-regulated miRNA is predicted to target Lst-Dermatopontin, a previously characterized shell matrix protein from another freshwater gastropod. This survey provides a foundation for future studies that would seek to characterize the functional role of these molecules in biomineralization or other processes of interest.

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