-
The Journal of Experimental Biology Apr 2015Recent developments in the study of pain in animals have demonstrated the potential for pain perception in a variety of wholly aquatic species such as molluscs,... (Review)
Review
Recent developments in the study of pain in animals have demonstrated the potential for pain perception in a variety of wholly aquatic species such as molluscs, crustaceans and fish. This allows us to gain insight into how the ecological pressures and differential life history of living in a watery medium can yield novel data that inform the comparative physiology and evolution of pain. Nociception is the simple detection of potentially painful stimuli usually accompanied by a reflex withdrawal response, and nociceptors have been found in aquatic invertebrates such as the sea slug Aplysia. It would seem adaptive to have a warning system that allows animals to avoid life-threatening injury, yet debate does still continue over the capacity for non-mammalian species to experience the discomfort or suffering that is a key component of pain rather than a nociceptive reflex. Contemporary studies over the last 10 years have demonstrated that bony fish possess nociceptors that are similar to those in mammals; that they demonstrate pain-related changes in physiology and behaviour that are reduced by painkillers; that they exhibit higher brain activity when painfully stimulated; and that pain is more important than showing fear or anti-predator behaviour in bony fish. The neurophysiological basis of nociception or pain in fish is demonstrably similar to that in mammals. Pain perception in invertebrates is more controversial as they lack the vertebrate brain, yet recent research evidence confirms that there are behavioural changes in response to potentially painful events. This review will assess the field of pain perception in aquatic species, focusing on fish and selected invertebrate groups to interpret how research findings can inform our understanding of the physiology and evolution of pain. Further, if we accept these animals may be capable of experiencing the negative experience of pain, then the wider implications of human use of these animals should be considered.
Topics: Animals; Behavior, Animal; Biological Evolution; Brain; Crustacea; Fishes; Mollusca; Nociception; Nociceptors; Pain Perception
PubMed: 25833131
DOI: 10.1242/jeb.088823 -
Proceedings of the National Academy of... Sep 2021Habituation and sensitization (nonassociative learning) are among the most fundamental forms of learning and memory behavior present in organisms that enable adaptation...
Habituation and sensitization (nonassociative learning) are among the most fundamental forms of learning and memory behavior present in organisms that enable adaptation and learning in dynamic environments. Emulating such features of intelligence found in nature in the solid state can serve as inspiration for algorithmic simulations in artificial neural networks and potential use in neuromorphic computing. Here, we demonstrate nonassociative learning with a prototypical Mott insulator, nickel oxide (NiO), under a variety of external stimuli at and above room temperature. Similar to biological species such as , habituation and sensitization of NiO possess time-dependent plasticity relying on both strength and time interval between stimuli. A combination of experimental approaches and first-principles calculations reveals that such learning behavior of NiO results from dynamic modulation of its defect and electronic structure. An artificial neural network model inspired by such nonassociative learning is simulated to show advantages for an unsupervised clustering task in accuracy and reducing catastrophic interference, which could help mitigate the stability-plasticity dilemma. Mott insulators can therefore serve as building blocks to examine learning behavior noted in biology and inspire new learning algorithms for artificial intelligence.
Topics: Algorithms; Animals; Aplysia; Artificial Intelligence; Electrons; Insulator Elements; Models, Neurological; Neural Networks, Computer; Neuronal Plasticity; Nickel; Synapses
PubMed: 34531299
DOI: 10.1073/pnas.2017239118 -
Molecules (Basel, Switzerland) Feb 2020Invertebrates are an important source of structurally-diverse and biologically-active halogenated metabolites. The sea hare Rang has long been known to possess... (Review)
Review
Invertebrates are an important source of structurally-diverse and biologically-active halogenated metabolites. The sea hare Rang has long been known to possess halogenated metabolites of dietary origin that are used as a self-defense mechanism. The compounds from Rang are comprised mainly of terpenoids and small percentages of C-15 acetogenins, indoles, macrolides, sterols and alkaloids with potent cytotoxic, anti-microbial and anti-inflammatory properties. For decades the metabolites discovered have been investigated for their medical and pharmaceutical applications, so much so that the ecological role of the metabolites has been overlooked. The interaction between Rang and its diet that is comprised of seaweed can provide information into the distribution and diversity of the seaweed, the application of bioaccumulated secondary metabolites as part of its defense mechanism and the potential roles of these metabolites for adaptation in the marine environment. This paper compiles the diversity of halogenated secondary metabolites documented from Rang.
Topics: Acetogenins; Alkaloids; Animals; Aplysia; Halogenation; Indoles; Macrolides; Seaweed; Sterols
PubMed: 32070000
DOI: 10.3390/molecules25040815 -
Science Signaling Nov 2017Elucidating the molecular mechanisms that maintain long-term memory is a fundamental goal of neuroscience. Accumulating evidence suggests that persistent signaling by... (Review)
Review
Elucidating the molecular mechanisms that maintain long-term memory is a fundamental goal of neuroscience. Accumulating evidence suggests that persistent signaling by the atypical protein kinase C (PKC) isoform protein kinase Mζ (PKMζ) might maintain synaptic long-term potentiation (LTP) and long-term memory. However, the role of PKMζ has been challenged by genetic data from PKMζ-knockout mice showing intact LTP and long-term memory. Moreover, the PKMζ inhibitor peptide ζ inhibitory peptide (ZIP) reverses LTP and erases memory in both wild-type and knockout mice. Data from four papers using additional isoform-specific genetic approaches have helped to reconcile these conflicting findings. First, a PKMζ-antisense approach showed that LTP and long-term memory in PKMζ-knockout mice are mediated through a compensatory mechanism that depends on another ZIP-sensitive atypical isoform, PKCι/λ. Second, short hairpin RNAs decreasing the amounts of individual atypical isoforms without inducing compensation disrupted memory in different temporal phases. PKCι/λ knockdown disrupted short-term memory, whereas PKMζ knockdown specifically erased long-term memory. Third, conditional PKCι/λ knockout induced compensation by rapidly activating PKMζ to preserve short-term memory. Fourth, a dominant-negative approach in the model system revealed that multiple PKCs form PKMs to sustain different types of long-term synaptic facilitation, with atypical PKM maintaining synaptic plasticity similar to LTP. Thus, under physiological conditions, PKMζ is the principal PKC isoform that maintains LTP and long-term memory. PKCι/λ can compensate for PKMζ, and because other isoforms could also maintain synaptic facilitation, there may be a hierarchy of compensatory mechanisms maintaining memory if PKMζ malfunctions.
Topics: Animals; Humans; Long-Term Potentiation; Memory; Protein Kinase C; Signal Transduction
PubMed: 29138296
DOI: 10.1126/scisignal.aao2327 -
Journal of Biotechnology Nov 2022Simultaneous coexpression of multiple proteins is essential for biotechnology and synthetic biology. Currently, the most popular polyprotein coexpression system utilizes...
Simultaneous coexpression of multiple proteins is essential for biotechnology and synthetic biology. Currently, the most popular polyprotein coexpression system utilizes the foot-and-mouth disease virus (FMDV) 2A peptide that mediates translational ribosome-skipping events. However, due to unfavorable consumer acceptance of transgenic products containing animal-virus sequences, novel non-viral 2A-like peptides from purple sea urchin (Strongylcentrotus purpuratus) and California sea slug (Aplysia californica) were investigated for polyprotein coexpression in this study. We demonstrated that these non-viral 2A sequences functioned similarly to their viral counterpart in polyprotein processing, in both plant and mammalian cells, and were successfully used to express a functional recombinant antibody. The new non-viral 2A-like sequences offer an alternative tool for engineering multigenic traits or production of protein complexes as biomedicine via coexpression of protein subunits.
Topics: Animals; Foot-and-Mouth Disease Virus; Mammals; Peptides; Polyproteins; Protein Subunits; Viral Proteins
PubMed: 35995093
DOI: 10.1016/j.jbiotec.2022.08.014 -
Cold Spring Harbor Perspectives in... Jul 2015Consolidation of implicit memory in the invertebrate Aplysia and explicit memory in the mammalian hippocampus are associated with remodeling and growth of preexisting... (Review)
Review
Consolidation of implicit memory in the invertebrate Aplysia and explicit memory in the mammalian hippocampus are associated with remodeling and growth of preexisting synapses and the formation of new synapses. Here, we compare and contrast structural components of the synaptic plasticity that underlies these two distinct forms of memory. In both cases, the structural changes involve time-dependent processes. Thus, some modifications are transient and may contribute to early formative stages of long-term memory, whereas others are more stable, longer lasting, and likely to confer persistence to memory storage. In addition, we explore the possibility that trans-synaptic signaling mechanisms governing de novo synapse formation during development can be reused in the adult for the purposes of structural synaptic plasticity and memory storage. Finally, we discuss how these mechanisms set in motion structural rearrangements that prepare a synapse to strengthen the same memory and, perhaps, to allow it to take part in other memories as a basis for understanding how their anatomical representation results in the enhanced expression and storage of memories in the brain.
Topics: Animals; Aplysia; Dendritic Spines; Hippocampus; Memory; Models, Neurological; Neuronal Plasticity; Signal Transduction; Synapses
PubMed: 26134321
DOI: 10.1101/cshperspect.a021758 -
Small GTPases 2021Since the discovery by Madaule and Axel in 1985 of the first Ras homologue (Rho) protein in and its human orthologue RhoB, membership in the Rho GTPase family has grown... (Review)
Review
Since the discovery by Madaule and Axel in 1985 of the first Ras homologue (Rho) protein in and its human orthologue RhoB, membership in the Rho GTPase family has grown to 20 proteins, with representatives in all eukaryotic species. These GTPases are molecular switches that cycle between active (GTP bound) and inactivate (GDP bound) states. The exchange of GDP for GTP on Rho GTPases is facilitated by guanine exchange factors (GEFs). Approximately 80 Rho GEFs have been identified to date, and only a few GEFs associate with microtubules. The guanine nucleotide exchange factor H1, GEF-H1, is a unique GEF that associates with microtubules and is regulated by the polymerization state of microtubule networks. This review summarizes the regulation and functions of GEF-H1 and discusses the roles of GEF-H1 in human diseases.
Topics: Animals; Disease; Gene Expression Regulation; Humans; Microtubules; Rho Guanine Nucleotide Exchange Factors
PubMed: 33126816
DOI: 10.1080/21541248.2020.1840889 -
Zootaxa Dec 2022During the past century eight species of sea hares of the genus Aplysia were recorded from Peru. However, there is disagreement about how many of these species are valid...
During the past century eight species of sea hares of the genus Aplysia were recorded from Peru. However, there is disagreement about how many of these species are valid and their taxonomy needs to be critically evaluated. Based on detailed morphological examinations, this study presents a redescription of Aplysia nigra d'Orbigny, 1837 and Aplysia inca d'Orbigny, 1837, the most common species of Aplysia along the Peruvian coast. They showed consistent morphological differences, mainly in the foot, parapodia development, opaline gland, jaws, radular teeth and penial morphology. Anatomical data for both species are provided for the first time, as well as a comparison with other species of Aplysia reported for the Eastern Pacific. The records of Aplysia keraudreni Rang, 1828, Aplysia dactylomela Rang, 1828 and Aplysia juliana Quoy & Gaimard, 1832 for Peruvian waters are likely erroneous and need to be verified based on collected specimens.
Topics: Animals; Aplysia; Peru; Species Specificity
PubMed: 37044529
DOI: 10.11646/zootaxa.5222.3.1 -
Frontiers in Neuroscience 2020The nervous system (NS) of invertebrates and vertebrates is composed of two main types of cells: neurons and glia. In both types of organisms, nerve cells have... (Review)
Review
The nervous system (NS) of invertebrates and vertebrates is composed of two main types of cells: neurons and glia. In both types of organisms, nerve cells have similarities in biochemistry and functionality. The neurons are in charge of the synapse, and the glial cells are in charge of important functions of neuronal and homeostatic modulation. Knowing the mechanisms by which NS cells work is important in the biomedical area for the diagnosis and treatment of neurological disorders. For this reason, cellular and animal models to study the properties and characteristics of the NS are always sought. Marine invertebrates are strategic study models for the biological sciences. The sea slug and the squid are two examples of marine key organisms in the neurosciences field. The principal characteristic of marine invertebrates is that they have a simpler NS that consists of few and larger cells, which are well organized and have accessible structures. As well, the close phylogenetic relationship between Chordata and Echinodermata constitutes an additional advantage to use these organisms as a model for the functionality of neuronal cells and their cellular plasticity. Currently, there is great interest in analyzing the signaling processes between neurons and glial cells, both in vertebrates and in invertebrates. However, only few types of glial cells of invertebrates, mostly insects, have been studied, and it is important to consider marine organisms' research. For this reason, the objective of the review is to present an update of the most relevant information that exists around the physiology of marine invertebrate neuronal and glial cells.
PubMed: 32132895
DOI: 10.3389/fnins.2020.00121 -
Journal of Neuroscience Methods Jan 2022Extracellular recording of nerve activities using suction electrodes is an easy yet powerful tool in characterizing neural activities in physiology and pathological...
BACKGROUND
Extracellular recording of nerve activities using suction electrodes is an easy yet powerful tool in characterizing neural activities in physiology and pathological conditions. The key factors that determine the quality of suction electrode recordings have not been fully investigated. New Methods: Here, we proposed a biophysical model to study the mechanisms underlying suction technology for axon recording. The model focuses on the interpretation of the recorded single neuron activity based on the location of the electrode, the integrity of the recorded tissue, and the tightness of the suction. To directly test these model predictions, we applied two channel recordings from the nerves in Aplysia californica, and analyzed the shape of the extracellularly recorded single neuron activity under various conditions.
RESULTS
We found that both the recording site and the integrity of the neural tissue impact the shape of the action potentials traveling along the axon. In practice, the tightness of the suction is the key parameter for high-quality recordings using a suction electrode. Comparison with Existing Methods: Experimental protocols that can improve precise positioning of the electrode tip to the target nerve, avoid tissue damage, enhance suction force, and maintain tightness are essential for high-quality suction recording from axons. Current methods have not emphasized on achieving and maintaining of the suction pressure during experimentation, and have sometimes ignored the impact of suction electrode position or tissue damage to the quality of the recorded neural signal.
CONCLUSIONS
A combined theoretical analysis and experimental approach is essential in improving neural recording technology. The work provides theoretical and practical guidelines to improve suction technology. This work also provides valuable insights to the improvement of several other extracellular recording technology in laboratory research or clinical settings.
Topics: Action Potentials; Electrodes; Neurons; Suction; Technology
PubMed: 34728256
DOI: 10.1016/j.jneumeth.2021.109401