scholarly journals Acetic acid activates distinct taste pathways in Drosophila to elicit opposing, state-dependent feeding responses

2018 ◽  
Author(s):  
Anita V. Devineni ◽  
Bei Sun ◽  
Anna Zhukovskaya ◽  
Richard Axel
Keyword(s):  
Acetic Acid ◽  
Behavioral Response ◽  
Internal State ◽  
Fruit Fly ◽  
Potential Toxicity ◽  
State Dependent ◽  
Aversive Response ◽  
Opposing Effects ◽  
Genetically Determined ◽  
Appetitive Response

ABSTRACTTaste circuits are genetically determined to elicit an innate appetitive or aversive response, ensuring that animals consume nutritious foods and avoid the ingestion of toxins. We have examined the response of the fruit fly Drosophila melanogaster to acetic acid, a tastant that can be a metabolic resource but can also be toxic to the fly. Our data reveal that flies accommodate these conflicting attributes of acetic acid by virtue of a hunger-dependent switch in their behavioral response to this stimulus. Fed flies show taste aversion to acetic acid, likely a response to its potential toxicity, whereas starved flies show a robust appetitive response that may reflect their overriding need for calories. These opposing responses are mediated by two different classes of taste neurons. Acetic acid activates both the sugar and bitter pathways, which have opposing effects on feeding behavior. Hunger shifts the response from aversion to attraction by enhancing the appetitive sugar pathway as well as suppressing the aversive bitter pathway. Thus a single tastant can drive opposing behaviors by activating distinct taste pathways modulated by internal state.

scholarly journals Acetic acid activates distinct taste pathways in Drosophila to elicit opposing, state-dependent feeding responses

eLife ◽  
2019 ◽  
Vol 8 ◽  
Author(s):  
Anita V Devineni ◽  
Bei Sun ◽  
Anna Zhukovskaya ◽  
Richard Axel
Keyword(s):  
Acetic Acid ◽  
Drosophila Melanogaster ◽  
Taste Aversion ◽  
Behavioral Response ◽  
Internal State ◽  
State Dependent ◽  
Aversive Response ◽  
Genetically Determined ◽  
Appetitive Response

Taste circuits are genetically determined to elicit an innate appetitive or aversive response, ensuring that animals consume nutritious foods and avoid the ingestion of toxins. We have examined the response of Drosophila melanogaster to acetic acid, a tastant that can be a metabolic resource but can also be toxic to the fly. Our data reveal that flies accommodate these conflicting attributes of acetic acid by virtue of a hunger-dependent switch in their behavioral response to this stimulus. Fed flies show taste aversion to acetic acid, whereas starved flies show a robust appetitive response. These opposing responses are mediated by two different classes of taste neurons, the sugar- and bitter-sensing neurons. Hunger shifts the behavioral response from aversion to attraction by enhancing the appetitive sugar pathway as well as suppressing the aversive bitter pathway. Thus a single tastant can drive opposing behaviors by activating distinct taste pathways modulated by internal state.

State-dependent parasitism by a facultative parasite of fruit flies

Parasitology ◽  
2017 ◽  
Vol 144 (11) ◽  
pp. 1468-1475 ◽  
Author(s):  
LIEN T. LUONG ◽  
TAYLOR BROPHY ◽  
EMILY STOLZ ◽  
SOLOMON J. CHAN
Keyword(s):  
Internal State ◽  
Fruit Fly ◽  
Model Systems ◽  
Life History Strategies ◽  
Free Living ◽  
Dependent Plasticity ◽  
Host Condition ◽  
State Dependent ◽  
Facultative Parasite ◽  
Condition State

SUMMARYParasites can evolve phenotypically plastic strategies for transmission such that a single genotype can give rise to a range of phenotypes depending on the environmental condition. State-dependent plasticity in particular can arise from individual differences in the parasite's internal state or the condition of the host. Facultative parasites serve as ideal model systems for investigating state-dependent plasticity because individuals can exhibit two life history strategies (free-living or parasitic) depending on the environment. Here, we experimentally show that the ectoparasitic mite Macrocheles subbadius is more likely to parasitize a fruit fly host if the female mite is mated; furthermore, the propensity to infect increased with the level of starvation experienced by the mite. Host condition also played an important role; hosts infected with moderate mite loads were more likely to gain additional infections in pairwise choice tests than uninfected flies. We also found that mites preferentially infected flies subjected to mechanical injury over uninjured flies. These results suggest that a facultative parasite's propensity to infect a host (i.e. switch from a free-living strategy) depends on both the parasite's internal state and host condition. Parasites often live in highly variable and changing environments, an infection strategy that is plastic is likely to be adaptive.

scholarly journals Genetic variation in dispersal plasticity in an aquatic host-parasite model system

2020 ◽  
Author(s):  
Giacomo Zilio ◽  
Louise Solveig Noergaard ◽  
Giovanni Petrucci ◽  
Nathalie Zeballos ◽  
Claire Gougat-Barbera ◽  
...  
Keyword(s):  
Genetic Variation ◽  
Internal State ◽  
Theoretical Models ◽  
Infection Prevalence ◽  
Main Role ◽  
Dependent Plasticity ◽  
Evolutionary Forces ◽  
State Dependent ◽  
Context Dependent ◽  
Host Parasite

Dispersal plays a main role in determining spatial dynamics, and both theory and empirical evidence indicate that evolutionary optima exist for constitutive or plastic dispersal behaviour. Plasticity in dispersal can be influenced by factors both internal (state-dependent) or external (context-dependent) to individuals. Parasitism is interesting in this context, as it can influence both types of host dispersal plasticity: individuals can disperse in response to internal infection status but might also respond to the presence of infected individuals around them. We still know little about the driving evolutionary forces of host dispersal plasticity, but a first requirement is the presence of a genetic basis on which natural selection can act. In this study, we used microcosm dispersal mazes to investigate plastic dispersal of 20 strains of the freshwater protist Paramecium caudatum in response to the bacterial parasite Holospora undulata. We additionally quantified the genetic component of the plastic responses, i.e. the heritability of state- and context-depended dispersal. We found that infection by the parasite can either increase or decrease dispersal of individual strains relative to the uninfected (state-dependent plasticity), and this to be heritable. We also found strain-specific change of dispersal of uninfected Paramecium when exposed to variable infection prevalence (context-dependent plasticity) with very low level of heritability. To our knowledge, this is the first explicit empirical demonstration and quantification of genetic variation of plastic dispersal in a host-parasite system, which could have important implications for meta-population and epidemiological dynamics. We discuss some of the underlying mechanisms of this variation and link our results to the existing theoretical models.

scholarly journals Threat induces changes in cardiac activity and metabolism negatively impacting survival in flies

2020 ◽  
Author(s):  
Natalia Barrios ◽  
Matheus Farias ◽  
Marta A Moita
Keyword(s):  
Internal State ◽  
Brain Activity ◽  
Dynamic Environment ◽  
Cardiac Activity ◽  
Fruit Fly ◽  
Physiological Changes ◽  
Neural Basis ◽  
Cardiac Responses ◽  
Cardiac Deceleration ◽  
Defensive Behaviours

AbstractAdjusting to a dynamic environment involves fast changes in the body’s internal state, characterized by coordinated alterations in brain activity, physiological and motor responses. Threat-induced defensive states are a classic example of coordinated adjustment of bodily responses, being cardiac regulation one of the best characterized in vertebrates. A great deal is known regarding the neural basis of invertebrate defensive behaviours, mainly in Drosophila melanogaster. However, whether physiological changes accompany these remains unknown. Here, we set out to describe the internal bodily state of fruit flies upon an inescapable threat and found cardiac acceleration during running and deceleration during freezing. In addition, we found that freezing leads to increased cardiac pumping from the abdomen towards the head-thorax, suggesting mobilization of energy resources. Concordantly, threat-triggered freezing reduces sugar levels in the hemolymph and renders flies less resistant to starvation. The cardiac responses observed during freezing were absent during spontaneous immobility, underscoring the active nature of freezing response. Finally, we show that baseline cardiac activity predicts the amount of freezing upon threat. This work reveals a remarkable similarity with the cardiac responses of vertebrates, suggesting an evolutionarily convergent defensive state in flies. Our findings are at odds with the widespread view that cardiac deceleration while freezing has first evolved in vertebrates and that it is energy sparing. Investigating the physiological changes coupled to defensive behaviours in the fruit fly has revealed that freezing is costly, yet accompanied by cardiac deceleration, and points to heart activity as a key modulator of defensive behaviours.

Modulation of Jellyfish Potassium Channels by External Potassium Ions

1999 ◽  
Vol 82 (4) ◽  
pp. 1728-1739 ◽  
Author(s):  
Nikita G. Grigoriev ◽  
J. David Spafford ◽  
Andrew N. Spencer
Keyword(s):  
Potassium Channels ◽  
Motor Neurons ◽  
Fruit Fly ◽  
Site Directed Mutagenesis ◽  
High Threshold ◽  
Extracellular Potassium ◽  
Potassium Ions ◽  
Polyorchis Penicillatus ◽  
State Dependent ◽  
Inactivation Mechanism

The amplitude of an A-like potassium current ( I Kfast) in identified cultured motor neurons isolated from the jellyfish Polyorchis penicillatus was found to be strongly modulated by extracellular potassium ([K+]out). When expressed in Xenopus oocytes, two jellyfish Shaker-like genes, jShak1 and jShak2, coding for potassium channels, exhibited similar modulation by [K+]out over a range of concentrations from 0 to 100 mM. jShak2-encoded channels also showed a decreased rate of inactivation and an increased rate of recovery from inactivation at high [K+]out. Using site-directed mutagenesis we show that inactivation of jShak2 can be ascribed to an unusual combination of a weak “implicit” N-type inactivation mechanism and a strong, fast, potassium-sensitive C-type mechanism. Interaction between the two forms of inactivation is responsible for the potassium dependence of cumulative inactivation. Inactivation of jShak1 was determined primarily by a strong “ball and chain” mechanism similar to fruit fly Shaker channels. Experiments using fast perfusion of outside-out patches with jShak2 channels were used to establish that the effects of [K+]out on the peak current amplitude and inactivation were due to processes occurring at either different sites located at the external channel mouth with different retention times for potassium ions, or at the same site(s) where retention time is determined by state-dependent conformations of the channel protein. The possible physiological implications of potassium sensitivity of high-threshold potassium A-like currents is discussed.

Conservation of the Ethanol-Induced Locomotor Stimulant Response among Arthropods

2015 ◽  
Vol 85 (1) ◽  
pp. 37-46 ◽  
Author(s):  
Christopher L. Kliethermes
Keyword(s):  
Drosophila Melanogaster ◽  
Behavioral Response ◽  
Wolf Spider ◽  
Fruit Fly ◽  
Vertebrate Species ◽  
Ethanol Sensitivity ◽  
Locomotor Stimulation ◽  
Arthropod Species ◽  
Acute Ethanol ◽  
Reinforcing Effects

Ethanol-induced locomotor stimulation has been variously described as reflective of the disinhibitory, euphoric, or reinforcing effects of ethanol and is commonly used as an index of acute ethanol sensitivity in rodents. The fruit fly Drosophila melanogaster also shows a locomotor stimulant response to ethanol that is believed to occur via conserved, ethanol-sensitive neurobiological mechanisms, but it is currently unknown whether this response is conserved among arthropod species or is idiosyncratic to D. melanogaster. The current experiments surveyed locomotor responses to ethanol in a phylogenetically diverse panel of insects and other arthropod species. A clear ethanol-induced locomotor stimulant response was seen in 9 of 13 Drosophilidae species tested, in 8 of 10 other species of insects, and in an arachnid (wolf spider) and a myriapod (millipede) species. Given the diverse phylogenies of the species that showed the response, these experiments support the hypothesis that locomotor stimulation is a conserved behavioral response to ethanol among arthropod species. Further comparative studies are needed to determine whether the specific neurobiological mechanisms known to underlie the stimulant response in D. melanogaster are conserved among arthropod and vertebrate species.

scholarly journals Two-Component Fermi Gas on Internal-State-Dependent Optical Lattices

2005 ◽  
Vol 95 (22) ◽  
Author(s):  
M. A. Cazalilla ◽  
A. F. Ho ◽  
T. Giamarchi
Keyword(s):  
Optical Lattices ◽  
Internal State ◽  
Fermi Gas ◽  
State Dependent ◽  
Two Component

scholarly journals Experience-dependent plasticity modulates ongoing activity in the antennal lobe and enhance odor representations

2021 ◽  
Author(s):  
Luis M. Franco ◽  
Emre Yaksi
Keyword(s):  
Antennal Lobe ◽  
Internal State ◽  
Brain Activity ◽  
Fruit Fly ◽  
Brain Regions ◽  
Projection Neurons ◽  
Ongoing Activity ◽  
Dependent Plasticity ◽  
Olfactory Glomeruli ◽  
The Brain

ABSTRACTOngoing neural activity has been observed across several brain regions and thought to reflect the internal state of the brain. Yet, it is not fully understood how ongoing brain activity interacts with sensory experience and shape sensory representations. Here, we show that projection neurons of the fruit fly antennal lobe exhibit spatiotemporally organized ongoing activity in the absence of odor stimulation. Upon repeated exposure to odors, we observe a gradual and long-lasting decrease in the amplitude and frequency of spontaneous calcium events, as well as a reorganization of correlations between olfactory glomeruli during ongoing activity. Accompanying these plastic changes, we find that repeated odor experience reduces trial-to-trial variability and enhances the specificity of odor representations. Our results reveal a previously undescribed experience-dependent plasticity of ongoing and sensory driven activity at peripheral levels of the fruit fly olfactory system.

scholarly journals A distributed dopamine-gated circuit underpins reproductive state-dependent behavior in Drosophila females

2021 ◽  
Author(s):  
Ariane C Boehm ◽  
Anja B Friedrich ◽  
Paul Bandow ◽  
K.P. Siju ◽  
Sydney Hunt ◽  
...  
Keyword(s):  
Internal State ◽  
Brain Regions ◽  
Neural Pathways ◽  
Reproductive State ◽  
Behavioral Screening ◽  
Whole Brain ◽  
State Dependent ◽  
Dependent Behavior ◽  
Output Neurons ◽  
And Behavior

Motherhood induces a drastic, sometimes long-lasting, change in internal state and behavior in most female animals. Here, we show that a mating-induced increase in olfactory attraction of female Drosophila flies to nutrients relies on interconnected neural pathways in the two higher olfactory brain regions, the lateral horn (LH) and the mushroom body (MB). Using whole brain calcium imaging, we find that mating does not induce a global change in the activity of the whole brain nor of entire brain regions, suggesting specific neuronal or network changes in the olfactory system. Systematic behavioral screening and electron microscopy (EM) connectomics identify two types of LH output neurons required for the attraction of females to polyamines -one of them previously implicated in the processing of male pheromones. In addition, we characterize multiple MB pathways capable of inducing or suppressing polyamine attraction, with synaptic connections to the identified LH neurons and a prominent role for the β′1 compartment. Moreover, β′1 dopaminergic neurons are modulated by mating and are sufficient to replace mating experience in virgins inducing the lasting behavioral switch in female preference. Taken together, our data in the fly suggests that reproductive state-dependent expression of female choice behavior is regulated by a dopamine-gated distributed learning circuit comprising both higher olfactory brain centers.

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