scholarly journals Neuroscience Needs Ethology: The Marked Example of the Moth Pheromone System

2020 ◽  
Author(s):  
Herve Thevenon
Keyword(s):  
Animal Species ◽  
Intrinsic Value ◽  
Sensory Information ◽  
Systemic Review ◽  
Auditory Stimuli ◽  
C Elegans ◽  
Pheromone System ◽  
Translational Studies ◽  
Insight Into ◽  
Genetic Toolkit

The key premise of translational studies is that knowledge gained in one animal species can be transposed to other animals. So far translational bridges have mainly relied on genetic and physiological similarities, in experimental setups where behaviours and environment are often oversimplified. These simplifications were recently criticised for decreasing the intrinsic value of the published results. The inclusion of wild behaviour and rich environments in neuroscience experimental designs is difficult to achieve because no animal model has it all. As an example, the genetic toolkit of moths species is virtually non-existent when compared to C. elegans, rats, mice, or zebrafish, however the balance is reversed for wild behaviours. The ethological knowledge gathered about the moth was instrumental for designing natural-like auditory stimuli, that were used in association with electrophysiology in order to understand how moths use these variable sounds produced by their predators in order to trump death. Conversely, we are still stuck with understanding how male moths make sense of their complex and diffuse olfactory landscape in order to locate conspecific females up to several hundred meters away, and precisely identify a conspecific in a sympatric swarm in order to reproduce. This systemic review articulates the ethological knowledge pertaining to this unresolved problem and leverages the paradigm to gain insight into how male moths process sparse and uncertain environmental sensory information.

scholarly journals Neuropeptides and Behaviors: How Small Peptides Regulate Nervous System Function and Behavioral Outputs

2021 ◽  
Vol 14 ◽  
Author(s):  
Umer Saleem Bhat ◽  
Navneet Shahi ◽  
Siju Surendran ◽  
Kavita Babu
Keyword(s):  
Nervous System ◽  
Behavioral Plasticity ◽  
Environmental Changes ◽  
Sensory Information ◽  
Synaptic Activity ◽  
Small Peptides ◽  
C Elegans ◽  
Wide Range ◽  
Nervous System Function ◽  
Insight Into

One of the reasons that most multicellular animals survive and thrive is because of the adaptable and plastic nature of their nervous systems. For an organism to survive, it is essential for the animal to respond and adapt to environmental changes. This is achieved by sensing external cues and translating them into behaviors through changes in synaptic activity. The nervous system plays a crucial role in constantly evaluating environmental cues and allowing for behavioral plasticity in the organism. Multiple neurotransmitters and neuropeptides have been implicated as key players for integrating sensory information to produce the desired output. Because of its simple nervous system and well-established neuronal connectome, C. elegans acts as an excellent model to understand the mechanisms underlying behavioral plasticity. Here, we critically review how neuropeptides modulate a wide range of behaviors by allowing for changes in neuronal and synaptic signaling. This review will have a specific focus on feeding, mating, sleep, addiction, learning and locomotory behaviors in C. elegans. With a view to understand evolutionary relationships, we explore the functions and associated pathophysiology of C. elegans neuropeptides that are conserved across different phyla. Further, we discuss the mechanisms of neuropeptidergic signaling and how these signals are regulated in different behaviors. Finally, we attempt to provide insight into developing potential therapeutics for neuropeptide-related disorders.

Neuropeptide signalling shapes feeding and reproductive behaviours in male C. elegans

2021 ◽  
Author(s):  
Matthew J Gadenne ◽  
Iris Hardege ◽  
Djordji Suleski ◽  
Paris Jaggers ◽  
Isabel Beets ◽  
...  
Keyword(s):  
Synaptic Connectivity ◽  
Male Mating ◽  
Sexually Dimorphic ◽  
C Elegans ◽  
Mating Efficiency ◽  
Sexually Dimorphic Expression ◽  
Pharyngeal Pumping ◽  
Insight Into ◽  
Feeding Behaviours ◽  
Dimorphic Expression

Sexual dimorphism occurs where different sexes of the same species display differences in characteristics not limited to reproduction. For the nematode Caenorhabditis elegans, in which the complete neuroanatomy has been solved for both hermaphrodites and males, sexually dimorphic features have been observed both in terms of the number of neurons and in synaptic connectivity. In addition, male behaviours, such as food-leaving to prioritise searching for mates, have been attributed to neuropeptides released from sex-shared or sex-specific neurons. In this study, we show that the lury-1 neuropeptide gene shows a sexually dimorphic expression pattern; being expressed in pharyngeal neurons in both sexes but displaying additional expression in tail neurons only in the male. We also show that lury-1 mutant animals show sex differences in feeding behaviours, with pharyngeal pumping elevated in hermaphrodites but reduced in males. LURY-1 also modulates male mating efficiency, influencing motor events during contact with a hermaphrodite. Our findings indicate sex-specific roles of this peptide in feeding and reproduction in C. elegans, providing further insight into neuromodulatory control of sexually dimorphic behaviours.

scholarly journals Notes on distribution and relative abundances of some animal species, and on climate in the Kruger National Park during prehistoric times

Koedoe ◽  
1989 ◽  
Vol 32 (1) ◽  
Author(s):  
Ina Plug
Keyword(s):  
National Park ◽  
Animal Species ◽  
Climatic Conditions ◽  
Kruger National Park ◽  
Archaeological Sites ◽  
Animal Population ◽  
Faunal Remains ◽  
The Past ◽  
Relative Abundances ◽  
Insight Into

Faunal remains obtained from archaeological sites in the Kruger National Park, provide valuable information on the distributions of animal species in the past. The relative abundances of some species are compared with animal population statistics of the present. The study of the faunal samples, which date from nearly 7 000 years before present until the nineteenth century, also provides insight into climatic conditions during prehistoric times.

scholarly journals C. elegans provide milk for their young

2020 ◽  
Author(s):  
Carina C. Kern ◽  
StJohn Townsend ◽  
Antoine Salzmann ◽  
Nigel B. Rendell ◽  
Graham W. Taylor ◽  
...  
Keyword(s):  
Sexual Maturity ◽  
Reproductive Effort ◽  
Pacific Salmon ◽  
Resource Transfer ◽  
C Elegans ◽  
Destructive Process ◽  
Severe Pathology ◽  
Intestinal Atrophy ◽  
Insight Into

AbstractAdult C. elegans hermaphrodites exhibit severe senescent pathology that begins to develop within days of reaching sexual maturity (Ezcurra et al., 2018; Garigan et al., 2002; Herndon et al., 2002; Wang et al., 2018). For example, after depletion of self-sperm, intestinal biomass is converted into yolk leading to intestinal atrophy and yolk steatosis (pseudocoelomic lipoprotein pools, PLPs) (Ezcurra et al., 2018; Garigan et al., 2002; Herndon et al., 2002; Sornda et al., 2019). These senescent pathologies are promoted by insulin/IGF-1 signalling (IIS), which also shortens lifespan (Ezcurra et al., 2018; Kenyon, 2010). This pattern of rapid and severe pathology in organs linked to reproduction is reminiscent of semelparous organisms where massive reproductive effort leads to rapid death (reproductive death) as in Pacific salmon (Finch, 1990; Gems et al., 2020). Moreover, destructive conversion of somatic biomass to support reproduction is a hallmark of reproductive death (Gems et al., 2020). Yet arguing against the occurrence of reproductive death in C. elegans is the apparent futility of post-reproductive yolk production. Here we show that this effort is not futile, since post-reproductive mothers vent yolk through their vulva, which is consumed by progeny and supports their growth; thus vented yolk functions as a milk, and C. elegans mothers exhibit a form of lactation. Moreover, IIS promotes lactation, thereby effecting a costly process of resource transfer from postreproductive mothers to offspring. These results support the view that C. elegans hermaphrodites exhibit reproductive death involving a self-destructive process of lactation that is promoted by IIS. They also provide new insight into how the strongly life-shortening effects of IIS in C. elegans evolved.

scholarly journals The Caenorhabditis elegans DEG-3/DES-2 Channel Is a Betaine-Gated Receptor Insensitive to Monepantel

Molecules ◽  
2022 ◽  
Vol 27 (1) ◽  
pp. 312
Author(s):  
Tina V. A. Hansen ◽  
Heinz Sager ◽  
Céline E. Toutain ◽  
Elise Courtot ◽  
Cédric Neveu ◽  
...  
Keyword(s):  
Caenorhabditis Elegans ◽  
Nicotinic Acetylcholine Receptors ◽  
Acetylcholine Receptors ◽  
Parasitic Nematode ◽  
Nematode Species ◽  
Xenopus Laevis Oocytes ◽  
Allosteric Modulators ◽  
C Elegans ◽  
Electrode Voltage ◽  
Insight Into

Natural plant compounds, such as betaine, are described to have nematocidal properties. Betaine also acts as a neurotransmitter in the free-living model nematode Caenorhabditis elegans, where it is required for normal motility. Worm motility is mediated by nicotinic acetylcholine receptors (nAChRs), including subunits from the nematode-specific DEG-3 group. Not all types of nAChRs in this group are associated with motility, and one of these is the DEG-3/DES-2 channel from C. elegans, which is involved in nociception and possibly chemotaxis. Interestingly, the activity of DEG-3/DES-2 channel from the parasitic nematode of ruminants, Haemonchus contortus, is modulated by monepantel and its sulfone metabolite, which belong to the amino-acetonitrile derivative anthelmintic drug class. Here, our aim was to advance the pharmacological knowledge of the DEG-3/DES-2 channel from C. elegans by functionally expressing the DEG-3/DES-2 channel in Xenopus laevis oocytes and using two-electrode voltage-clamp electrophysiology. We found that the DEG-3/DES-2 channel was more sensitive to betaine than ACh and choline, but insensitive to monepantel and monepantel sulfone when used as direct agonists and as allosteric modulators in co-application with betaine. These findings provide important insight into the pharmacology of DEG-3/DES-2 from C. elegans and highlight the pharmacological differences between non-parasitic and parasitic nematode species.

scholarly journals Systematic characterization and genetic interaction analysis of adhesins in Candida albicans virulence

2020 ◽  
Author(s):  
Sierra Rosiana ◽  
Liyang Zhang ◽  
Grace H. Kim ◽  
Alexey V. Revtovich ◽  
Arjun Sukumaran ◽  
...  
Keyword(s):  
Candida Albicans ◽  
Genetic Interaction ◽  
Interaction Analysis ◽  
Genetic Interactions ◽  
Fungal Virulence ◽  
C Elegans ◽  
Adhesin Proteins ◽  
Insight Into

AbstractCandida albicans is a microbial fungus that exists as a commensal member of the human microbiome and an opportunistic pathogen. Cell surface-associated adhesin proteins play a crucial role in C. albicans’ ability to undergo cellular morphogenesis, develop robust biofilms, colonize, and cause infection in a host. However, a comprehensive analysis of the role and relationships between these adhesins has not been explored. We previously established a CRISPR-based platform for efficient generation of single- and double-gene deletions in C. albicans, which was used to construct a library of 144 mutants, comprising 12 unique adhesin genes deleted singly, or in every possible combination of double deletions. Here, we exploit this adhesin mutant library to explore the role of adhesin proteins in C. albicans virulence. We perform a comprehensive, high-throughput screen of this library, using Caenorhabditis elegans as a simplified model host system, which identified mutants critical for virulence and significant genetic interactions. We perform follow-up analysis to assess the ability of high- and low-virulence strains to undergo cellular morphogenesis and form biofilms in vitro, as well as to colonize the C. elegans host. We further perform genetic interaction analysis to identify novel significant negative genetic interactions between adhesin mutants, whereby combinatorial perturbation of these genes significantly impairs virulence, more than expected based on virulence of the single mutant constituent strains. Together, this yields important new insight into the role of adhesins, singly and in combinations, in mediating diverse facets of virulence of this critical fungal pathogen.SummaryCandida albicans is a human fungal pathogen and cause of life-threatening systemic infections. Cell surface-associated adhesins play a central role in this pathogen’s ability to establish infection. Here, we provide a comprehensive analysis of adhesin factors, and their role in fungal virulence. Exploiting a high-throughput workflow, we screened an adhesin mutant library using C. elegans as a simple model host, and identified mutants and genetic interactions involved in virulence. We found that adhesin mutants are impaired in in vitro pathogenicity, irrespective of their virulence. Together, this work provides new insight into the role of adhesin factors in mediating fungal virulence.

scholarly journals Fractal scaling of C. elegans behavior is shaped by insulin signaling

2021 ◽  
Author(s):  
Yukinobu Arata ◽  
Itsuki Shiga ◽  
Yusaku Ikeda ◽  
Hiroshi Kimura ◽  
Peter Jurica ◽  
...  
Keyword(s):  
Residence Time ◽  
Insulin Signaling ◽  
Time Distribution ◽  
Animal Species ◽  
Power Law Distribution ◽  
Fractal Scaling ◽  
C Elegans ◽  
Fractal Analyses ◽  
Patients With Diabetes ◽  
Behavioral Activities

Abstract Fractal scaling governs the complex behavior of various animal species and, in humans, can be altered by neurodegenerative diseases and aging1. However, the mechanism underlying fractal scaling remains unknown. Here, we videorecorded C. elegans that had been cultured in a microfluidic device for 3 days and analyzed temporal patterns of C. elegans actions by fractal analyses. The residence-time distribution of C. elegans shared a common feature with those of human and mice2–4. Specifically, the residence-time power-law distribution of the active state changed to an exponential-like decline at a longer time scale, whereas this change did not occur in the inactive state. The exponential-like decline disappeared in starved C. elegans but was restored by culturing animals with glucose. The exponential-like decline similarly disappeared in insulin-signaling daf-2 and daf-16 mutants. Therefore, we conclude that insulin signaling regulates fractal scaling of C. elegans behavior. Our findings indicate that neurosensory modulation of C. elegans behavior by insulin signaling is achieved by regulation of fractal scaling. In humans, diabetes mellitus is associated with depression, bipolar disorder, and anxiety disorder5, which affect daily behavioral activities. We hypothesize that comorbid behavioral defects in patients with diabetes may be attributed to altered fractal scaling of human behavior.

scholarly journals Microtubule-dependent ribosome localization in C. elegans neurons

eLife ◽  
2017 ◽  
Vol 6 ◽  
Author(s):  
Kentaro Noma ◽  
Alexandr Goncharov ◽  
Mark H Ellisman ◽  
Yishi Jin
Keyword(s):  
Cell Biology ◽  
Neuronal Development ◽  
Ultrastructural Level ◽  
Synthesis Methods ◽  
Tissue Specific ◽  
C Elegans ◽  
Multicellular Organisms ◽  
Axonal Trafficking ◽  
Insight Into

Subcellular localization of ribosomes defines the location and capacity for protein synthesis. Methods for in vivo visualizing ribosomes in multicellular organisms are desirable in mechanistic investigations of the cell biology of ribosome dynamics. Here, we developed an approach using split GFP for tissue-specific visualization of ribosomes in Caenorhabditis elegans. Labeled ribosomes are detected as fluorescent puncta in the axons and synaptic terminals of specific neuron types, correlating with ribosome distribution at the ultrastructural level. We found that axonal ribosomes change localization during neuronal development and after axonal injury. By examining mutants affecting axonal trafficking and performing a forward genetic screen, we showed that the microtubule cytoskeleton and the JIP3 protein UNC-16 exert distinct effects on localization of axonal and somatic ribosomes. Our data demonstrate the utility of tissue-specific visualization of ribosomes in vivo, and provide insight into the mechanisms of active regulation of ribosome localization in neurons.

scholarly journals Novel Technological Advances in Functional Connectomics in C. elegans

2019 ◽  
Vol 7 (2) ◽  
pp. 8 ◽  
Author(s):  
DiLoreto ◽  
Chute ◽  
Bryce ◽  
Srinivasan
Keyword(s):  
Nervous System ◽  
Computational Modeling ◽  
Activity Patterns ◽  
Sensory Information ◽  
Neuronal Cell ◽  
Network Models ◽  
Connectivity Matrix ◽  
C Elegans ◽  
Technological Advances

The complete structure and connectivity of the Caenorhabditis elegans nervous system (“mind of a worm”) was first published in 1986, representing a critical milestone in the field of connectomics. The reconstruction of the nervous system (connectome) at the level of synapses provided a unique perspective of understanding how behavior can be coded within the nervous system. The following decades have seen the development of technologies that help understand how neural activity patterns are connected to behavior and modulated by sensory input. Investigations on the developmental origins of the connectome highlight the importance of role of neuronal cell lineages in the final connectivity matrix of the nervous system. Computational modeling of neuronal dynamics not only helps reconstruct the biophysical properties of individual neurons but also allows for subsequent reconstruction of whole-organism neuronal network models. Hence, combining experimental datasets with theoretical modeling of neurons generates a better understanding of organismal behavior. This review discusses some recent technological advances used to analyze and perturb whole-organism neuronal function along with developments in computational modeling, which allows for interrogation of both local and global neural circuits, leading to different behaviors. Combining these approaches will shed light into how neural networks process sensory information to generate the appropriate behavioral output, providing a complete understanding of the worm nervous system.

A Separability Principle, Contrast Cases, and Contributory Dispositions

2020 ◽  
Vol 36 (1) ◽  
pp. 35-44
Author(s):  
Zak A. Kopeikin ◽  
Keyword(s):  
Intrinsic Value ◽  
Value Theory ◽  
Ethical Methodology ◽  
Separability Principle ◽  
Insight Into

The aim of this paper is to clarify the use of contrast cases—which are pairs of cases in which the feature under examination is varied and all else is held fixed—in ethical methodology. In another paper, I argue that we must reject a separability principle which is thought to allow one to use contrast cases to infer truths about intrinsic value (Kopeikin, 2019). Here I offer a different criticism that has a positive upshot about what we are licensed to infer from contrast cases. This provides clarification about the epistemic use of contrast cases in value theory and insight into what we can glean from contrast cases.

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