Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 5.497
Filtrar
1.
Curr Biol ; 33(2): 351-363.e3, 2023 Jan 23.
Artigo em Inglês | MEDLINE | ID: mdl-36610393

RESUMO

Circadian clocks align various behaviors such as locomotor activity, sleep/wake, feeding, and mating to times of day that are most adaptive. How rhythmic information in pacemaker circuits is translated to neuronal outputs is not well understood. Here, we used brain-wide, 24-h in vivo calcium imaging in the Drosophila brain and searched for circadian rhythmic activity among identified clusters of dopaminergic (DA) and peptidergic neurosecretory (NS) neurons. Such rhythms were widespread and imposed by the PERIOD-dependent clock activity within the ∼150-cell circadian pacemaker network. The rhythms displayed either a morning (M), evening (E), or mid-day (MD) phase. Different subgroups of circadian pacemakers imposed neural activity rhythms onto different downstream non-clock neurons. Outputs from the canonical M and E pacemakers converged to regulate DA-PPM3 and DA-PAL neurons. E pacemakers regulate the evening-active DA-PPL1 neurons. In addition to these canonical M and E oscillators, we present evidence for a third dedicated phase occurring at mid-day: the l-LNv pacemakers present the MD activity peak, and they regulate the MD-active DA-PPM1/2 neurons and three distinct NS cell types. Thus, the Drosophila circadian pacemaker network is a polyphasic rhythm generator. It presents dedicated M, E, and MD phases that are functionally transduced as neuronal outputs to organize diverse daily activity patterns in downstream circuits.


Assuntos
Relógios Circadianos , Proteínas de Drosophila , Animais , Drosophila melanogaster/fisiologia , Atividade Motora/fisiologia , Ritmo Circadiano/fisiologia , Drosophila/fisiologia , Proteínas de Drosophila/genética , Proteínas de Drosophila/metabolismo , Neurônios Dopaminérgicos/metabolismo
2.
Curr Biol ; 33(2): 321-335.e6, 2023 Jan 23.
Artigo em Inglês | MEDLINE | ID: mdl-36603587

RESUMO

Visual systems extract multiple features from a scene using parallel neural circuits. Ultimately, the separate neural signals must come together to coherently influence action. Here, we characterize a circuit in Drosophila that integrates multiple visual features related to imminent threats to drive evasive locomotor turns. We identified, using genetic perturbation methods, a pair of visual projection neurons (LPLC2) and descending neurons (DNp06) that underlie evasive flight turns in response to laterally moving or approaching visual objects. Using two-photon calcium imaging or whole-cell patch clamping, we show that these cells indeed respond to both translating and approaching visual patterns. Furthermore, by measuring visual responses of LPLC2 neurons after genetically silencing presynaptic motion-sensing neurons, we show that their visual properties emerge by integrating multiple visual features across two early visual structures: the lobula and the lobula plate. This study highlights a clear example of how distinct visual signals converge on a single class of visual neurons and then activate premotor neurons to drive action, revealing a concise visuomotor pathway for evasive flight maneuvers in Drosophila.


Assuntos
Drosophila , Percepção de Movimento , Animais , Drosophila/fisiologia , Drosophila melanogaster/fisiologia , Neurônios Motores/fisiologia , Interneurônios/metabolismo , Cálcio/metabolismo , Vias Visuais , Percepção de Movimento/fisiologia , Voo Animal/fisiologia
3.
Proc Natl Acad Sci U S A ; 120(5): e2217532120, 2023 Jan 31.
Artigo em Inglês | MEDLINE | ID: mdl-36689661

RESUMO

The gut microbiome is well known to impact host physiology and health. Given widespread control of physiology by circadian clocks, we asked how the microbiome interacts with circadian rhythms in the Drosophila gut. The microbiome did not cycle in flies fed ad libitum, and timed feeding (TF) drove limited cycling only in clockless per01 flies. However, TF and loss of the microbiome influenced the composition of the gut cycling transcriptome, independently and together. Moreover, both interventions increased the amplitude of rhythmic gene expression, with effects of TF at least partly due to changes in histone acetylation. Contrary to expectations, timed feeding rendered animals more sensitive to stress. Analysis of microbiome function in circadian physiology revealed that germ-free flies reset more rapidly with shifts in the light:dark cycle. We propose that the microbiome stabilizes cycling in the host gut to prevent rapid fluctuations with changing environmental conditions.


Assuntos
Relógios Circadianos , Microbioma Gastrointestinal , Animais , Ritmo Circadiano/genética , Drosophila/fisiologia , Fotoperíodo
4.
Biol Open ; 12(1)2023 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-36606515

RESUMO

Developmental neuronal pruning is a process by which neurons selectively remove excessive or unnecessary neurite without causing neuronal death. Importantly, this process is widely used for the refinement of neural circuits in both vertebrates and invertebrates, and may also contribute to the pathogenesis of neuropsychiatric disorders, such as autism and schizophrenia. In the peripheral nervous system (PNS), class IV dendritic arborization (da) sensory neurons of Drosophila, selectively remove the dendrites without losing their somas and axons, while the dendrites and axons of mushroom body (MB) γ neuron in the central nervous system (CNS) are eliminated by localized fragmentation during metamorphosis. Alternatively, dendrite pruning of ddaC neurons is usually investigated via live-cell imaging, while dissection and fixation are currently used for evaluating MB γ neuron axon pruning. Thus, an excellent model system to assess axon specific pruning directly via live-cell imaging remains elusive. Here, we report that the Drosophila motor neuron offers a unique advantage for studying axon pruning. Interestingly, we uncover that long-range projecting axon bundle from soma at ventral nerve cord (VNC), undergoes degeneration rather than retraction during metamorphosis. Strikingly, the pruning process of the motor axon bundle is straightforward to investigate via live imaging and it occurs approximately at 22 h after pupal formation (APF), when axon bundles are completely cleared. Consistently, the classical axon pruning regulators in the Drosophila MB γ neuron, including TGF-ß signaling, ecdysone signaling, JNK signaling, and the ubiquitin-proteasome system are also involved in governing motor axon pruning. Finally, our findings establish an unprecedented axon pruning mode that will serve to systematically screen and identify undiscovered axon pruning regulators. This article has an associated First Person interview with the first author of the paper.


Assuntos
Axônios , Drosophila , Animais , Drosophila/fisiologia , Neurônios Motores , Neuritos , Plasticidade Neuronal
5.
Sci Rep ; 13(1): 383, 2023 Jan 07.
Artigo em Inglês | MEDLINE | ID: mdl-36611081

RESUMO

Acoustic communication signals diversify even on short evolutionary time scales. To understand how the auditory system underlying acoustic communication could evolve, we conducted a systematic comparison of the early stages of the auditory neural circuit involved in song information processing between closely-related fruit-fly species. Male Drosophila melanogaster and D. simulans produce different sound signals during mating rituals, known as courtship songs. Female flies from these species selectively increase their receptivity when they hear songs with conspecific temporal patterns. Here, we firstly confirmed interspecific differences in temporal pattern preferences; D. simulans preferred pulse songs with longer intervals than D. melanogaster. Primary and secondary song-relay neurons, JO neurons and AMMC-B1 neurons, shared similar morphology and neurotransmitters between species. The temporal pattern preferences of AMMC-B1 neurons were also relatively similar between species, with slight but significant differences in their band-pass properties. Although the shift direction of the response property matched that of the behavior, these differences are not large enough to explain behavioral differences in song preferences. This study enhances our understanding of the conservation and diversification of the architecture of the early-stage neural circuit which processes acoustic communication signals.


Assuntos
Drosophila melanogaster , Drosophila , Animais , Masculino , Feminino , Drosophila/fisiologia , Drosophila melanogaster/fisiologia , Corte , Evolução Biológica , Neurônios , Drosophila simulans , Comportamento Sexual Animal/fisiologia , Vocalização Animal/fisiologia
6.
Curr Biol ; 33(2): 263-275.e4, 2023 Jan 23.
Artigo em Inglês | MEDLINE | ID: mdl-36543168

RESUMO

Epithelial cells remodel cell adhesion and change their neighbors to shape a tissue. This cellular rearrangement proceeds in three steps: the shrinkage of a junction, exchange of junctions, and elongation of the newly generated junction. Herein, by combining live imaging and physical modeling, we showed that the formation of myosin-II (myo-II) cables around the cell vertices underlies the exchange of junctions in the Drosophila wing epithelium. The local and transient detachment of myo-II from the cell cortex is regulated by the LIM domain-containing protein Jub and the tricellular septate junction protein M6. Moreover, we found that M6 shifts to the adherens junction plane on jub RNAi and that Jub is persistently retained at reconnecting junctions in m6 RNAi cells. This interplay between Jub and M6 can depend on the junction length and thereby couples the detachment of cortical myo-II cables and the shrinkage/elongation of the junction during cell rearrangement. Furthermore, we developed a mechanical model based on the wetting theory and clarified how the physical properties of myo-II cables are integrated with the junction geometry to induce the transition between the attached and detached states and support the unidirectionality of cell rearrangement. Collectively, this study elucidates the orchestration of geometry, mechanics, and signaling for exchanging junctions.


Assuntos
Proteínas de Drosophila , Drosophila , Animais , Drosophila/fisiologia , Drosophila melanogaster/genética , Drosophila melanogaster/metabolismo , Proteínas de Drosophila/metabolismo , Epitélio/metabolismo , Miosinas/genética , Miosinas/metabolismo , Junções Aderentes/metabolismo , Junções Intercelulares/metabolismo , Miosina Tipo II/metabolismo
7.
Artigo em Inglês | MEDLINE | ID: mdl-36554435

RESUMO

Although studies have shown that myomesin 2 (MYOM2) mutations can lead to hypertrophic cardiomyopathy (HCM), a common cardiovascular disease that has a serious impact on human life, the effect of MYOM2 on cardiac function and lifespan in humans is unknown. In this study, dMnM (MYOM2 homologs) knockdown in cardiomyocytes resulted in diastolic cardiac defects (diastolic dysfunction and arrhythmias) and increased cardiac oxidative stress. Furthermore, the knockdown of dMnM in indirect flight muscle (IFM) reduced climbing ability and shortened lifespan. However, regular exercise significantly ameliorated diastolic cardiac dysfunction, arrhythmias, and oxidative stress triggered by dMnM knockdown in cardiac myocytes and also reversed the reduction in climbing ability and shortening of lifespan caused by dMnM knockdown in Drosophila IFM. In conclusion, these results suggest that Drosophila cardiomyocyte dMnM knockdown leads to cardiac functional defects, while dMnM knockdown in IFM affects climbing ability and lifespan. Furthermore, regular exercise effectively upregulates cardiomyocyte dMnM expression levels and ameliorates cardiac functional defects caused by Drosophila cardiomyocyte dMnM knockdown by increasing cardiac antioxidant capacity. Importantly, regular exercise ameliorates the shortened lifespan caused by dMnM knockdown in IFM.


Assuntos
Proteínas de Drosophila , Cardiopatias Congênitas , Animais , Humanos , Drosophila/fisiologia , Longevidade , Proteínas de Drosophila/genética , Proteínas de Drosophila/metabolismo , Regulação para Baixo , Exercício Físico
8.
BMC Biol ; 20(1): 283, 2022 12 17.
Artigo em Inglês | MEDLINE | ID: mdl-36527001

RESUMO

BACKGROUND: Like most living organisms, the fruit fly Drosophila melanogaster exhibits strong and diverse behavioural reactions to light. Drosophila is a diurnal animal that displays both short- and long-term responses to light, important for, instance, in avoidance and light wavelength preference, regulation of eclosion, courtship, and activity, and provides an important model organism for understanding the regulation of circadian rhythms both at molecular and circuit levels. However, the assessment and comparison of light-based behaviours is still a challenge, mainly due to the lack of a standardised platform to measure behaviour and different protocols created across studies. Here, we describe the Drosophila Interactive System for Controlled Optical manipulations (DISCO), a low-cost, automated, high-throughput device that records the flies' activity using infrared beams while performing LED light manipulations. RESULTS: To demonstrate the effectiveness of this tool and validate its potential as a standard platform, we developed a number of distinct assays, including measuring the locomotor response of flies exposed to sudden darkness (lights-off) stimuli. Both white-eyed and red-eyed wild-type flies exhibit increased activity after the application of stimuli, while no changes can be observed in Fmr1 null allele flies, a model of fragile X syndrome. Next, to demonstrate the use of DISCO in long-term protocols, we monitored the circadian rhythm of the flies for 48 h while performing an alcohol preference test. We show that increased alcohol consumption happens intermittently throughout the day, especially in the dark phases. Finally, we developed a feedback-loop algorithm to implement a place preference test based on the flies' innate aversion to blue light and preference for green light. We show that both white-eyed and red-eyed wild-type flies were able to learn to avoid the blue-illuminated zones. CONCLUSIONS: Our results demonstrate the versatility of DISCO for a range of protocols, indicating that this platform can be used in a variety of ways to study light-dependent behaviours in flies.


Assuntos
Proteínas de Drosophila , Drosophila melanogaster , Animais , Drosophila melanogaster/fisiologia , Ritmo Circadiano/fisiologia , Drosophila/fisiologia , Atividade Motora/fisiologia , Visão Ocular , Proteína do X Frágil de Retardo Mental
9.
STAR Protoc ; 3(4): 101806, 2022 12 16.
Artigo em Inglês | MEDLINE | ID: mdl-36386873

RESUMO

Fruit flies sense the features of food that are driven by particle size, including smoothness versus grittiness, by deflection of sensilla decorating the labellum, and md-L neurons. We describe adaptation of the Drosophila proboscis extension response assay, including steps to perform the taste tests and score behavioral responses, to determine preferences to foods with different sized particles. We also describe calcium imaging in GCaMP-expressing flies to assess the responses of md-L neurons to different levels of taste sensilla deflection. For complete details on the use and execution of this protocol, please refer to Li and Montell. (2021).


Assuntos
Borboletas , Drosophila , Animais , Drosophila/fisiologia , Paladar/fisiologia , Sensilas , Alimentos
10.
Elife ; 112022 11 18.
Artigo em Inglês | MEDLINE | ID: mdl-36398882

RESUMO

The agricultural pest Drosophila suzukii differs from most other Drosophila species in that it lays eggs in ripe, rather than overripe, fruit. Previously, we showed that changes in bitter taste sensation accompanied this adaptation (Dweck et al., 2021). Here, we show that D. suzukii has also undergone a variety of changes in sweet taste sensation. D. suzukii has a weaker preference than Drosophila melanogaster for laying eggs on substrates containing all three primary fruit sugars: sucrose, fructose, and glucose. Major subsets of D. suzukii taste sensilla have lost electrophysiological responses to sugars. Expression of several key sugar receptor genes is reduced in the taste organs of D. suzukii. By contrast, certain mechanosensory channel genes, including no mechanoreceptor potential C, are expressed at higher levels in the taste organs of D. suzukii, which has a higher preference for stiff substrates. Finally, we find that D. suzukii responds differently from D. melanogaster to combinations of sweet and mechanosensory cues. Thus, the two species differ in sweet sensation, mechanosensation, and their integration, which are all likely to contribute to the differences in their egg-laying preferences in nature.


Assuntos
Drosophila melanogaster , Drosophila , Animais , Drosophila/fisiologia , Drosophila melanogaster/fisiologia , Açúcares , Oviposição , Sensação
11.
Sci Robot ; 7(72): eabq8184, 2022 Nov 23.
Artigo em Inglês | MEDLINE | ID: mdl-36417499

RESUMO

Tiny "gnat robots," weighing just a few milligrams, were first conjectured in the 1980s. How to stabilize one if it were to hover like a small insect has not been answered. Challenges include the requirement that sensors be both low mass and high bandwidth and that silicon-micromachined rate gyroscopes are too heavy. The smallest robot to perform controlled hovering uses a sensor suite weighing hundreds of milligrams. Here, we demonstrate that an accelerometer represents perhaps the most direct way to stabilize flight while satisfying the extreme size, speed, weight, and power constraints of a flying robot even as it scales down to just a few milligrams. As aircraft scale reduces, scaling physics dictates that the ratio of aerodynamic drag to mass increases. This results in reduced noise in an accelerometer's airspeed measurement. We show through simulation and experiment on a 30-gram robot that a 2-milligram off-the-shelf accelerometer is able in principle to stabilize a 10-milligram robot despite high noise in the sensor itself. Inspired by wind-vision sensory fusion in the flight controller of the fruit fly Drosophila melanogaster, we then added a tiny camera and efficient, fly-inspired autocorrelation-based visual processing to allow the robot to estimate and reject wind as well as control its attitude and flight velocity using a Kalman filter. Our biology-inspired approach, validated on a small flying helicopter, has a wind gust response comparable to the fruit fly and is small and efficient enough for a 10-milligram flying vehicle (weighing less than a grain of rice).


Assuntos
Robótica , Vento , Animais , Voo Animal/fisiologia , Asas de Animais/fisiologia , Drosophila melanogaster , Drosophila/fisiologia
12.
Curr Biol ; 32(22): 4900-4913.e4, 2022 Nov 21.
Artigo em Inglês | MEDLINE | ID: mdl-36327980

RESUMO

Elucidating how the distinct components of synaptic plasticity dynamically orchestrate the distinct stages of memory acquisition and maintenance within neuronal networks remains a major challenge. Specifically, plasticity processes tuning the functional and also structural state of presynaptic active zone (AZ) release sites are widely observed in vertebrates and invertebrates, but their behavioral relevance remains mostly unclear. We here provide evidence that a transient upregulation of presynaptic AZ release site proteins supports aversive olfactory mid-term memory in the Drosophila mushroom body (MB). Upon paired aversive olfactory conditioning, AZ protein levels (ELKS-family BRP/(m)unc13-family release factor Unc13A) increased for a few hours with MB-lobe-specific dynamics. Kenyon cell (KC, intrinsic MB neurons)-specific knockdown (KD) of BRP did not affect aversive olfactory short-term memory (STM) but strongly suppressed aversive mid-term memory (MTM). Different proteins crucial for the transport of AZ biosynthetic precursors (transport adaptor Aplip1/Jip-1; kinesin motor IMAC/Unc104; small GTPase Arl8) were also specifically required for the formation of aversive olfactory MTM. Consistent with the merely transitory increase of AZ proteins, BRP KD did not interfere with the formation of aversive olfactory long-term memory (LTM; i.e., 1 day). Our data suggest that the remodeling of presynaptic AZ refines the MB circuitry after paired aversive conditioning, over a time window of a few hours, to display aversive olfactory memories.


Assuntos
Proteínas de Drosophila , Corpos Pedunculados , Animais , Corpos Pedunculados/fisiologia , Drosophila/fisiologia , Proteínas de Drosophila/metabolismo , Aprendizagem da Esquiva/fisiologia , Memória de Curto Prazo/fisiologia
13.
Biol Open ; 11(10)2022 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-36285699

RESUMO

Many insects inhabiting temperate climates are faced with changing environmental conditions throughout the year. Depending on the species, these environmental fluctuations can be experienced within a single generation or across multiple generations. Strategies for dealing with these seasonal changes vary across populations. Drosophila mojavensis is a cactophilic Drosophila species endemic to the Sonoran Desert. The Sonoran Desert regularly reaches temperatures of 50°C in the summer months. As individuals of this population are rare to collect in the summer months, we simulated the cycling temperatures experienced by D. mojavensis in the Sonoran Desert from April to July (four generations) in a temperature- and light-controlled chamber, to understand the physiological and life history changes that allow this population to withstand these conditions. In contrast to our hypothesis of a summer aestivation, we found that D. mojavensis continue to reproduce during the summer months, albeit with lower viability, but the adult survivorship of the population is highly reduced during this period. As expected, stress resistance increased during the summer months in both the adult and the larval stages. This study examines several strategies for withstanding the Sonoran Desert summer conditions which may be informative in the study of other desert endemic species.


Assuntos
Adaptação Fisiológica , Drosophila , Animais , Drosophila/fisiologia , Estações do Ano , Aclimatação
14.
Am J Physiol Cell Physiol ; 323(5): C1539-C1547, 2022 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-36189971

RESUMO

All living organisms experience daily environmental cycles and have consequently evolved to synchronize and adapt to this changing environment. Biological processes such as hormonal secretion, body temperature, and sleep follow daily cycles called circadian rhythms that are driven by a molecular clock running in most cells and tissues of the body. This clock is composed of transcriptional-translational negative feedback loops involving clock genes and proteins. This molecular mechanism functions with a period of ∼24 h, and it promotes daily rhythms in the expression of numerous genes. For this robust mechanism to function, the abundance and activity of clock proteins need to be tightly regulated. One of the mechanisms by which this can be achieved is ubiquitination. Indeed, many ubiquitin ligases can tag core clock proteins to target them for proteasomal degradation. However, deubiquitinases can reverse this process by removing or modifying these ubiquitin signals and are thus important enzymes in clock protein homeostasis and regulation. Recent studies on the mammalian and Drosophila clock mechanisms have identified a number of deubiquitinases able to stabilize core clock proteins, change their cellular localization or even regulate their activity. In this review, we aim to discuss the fundamental roles of ubiquitination and deubiquitination in the circadian clock by presenting all deubiquitinases found to be involved in circadian rhythms with the aim to give a global view of recent advances in this emerging field.


Assuntos
Relógios Circadianos , Animais , Proteínas CLOCK/genética , Ritmo Circadiano/genética , Drosophila/fisiologia , Enzimas Desubiquitinantes/genética , Ubiquitinas , Mamíferos
15.
Elife ; 112022 10 03.
Artigo em Inglês | MEDLINE | ID: mdl-36190119

RESUMO

Circadian clocks are highly conserved transcriptional regulators that control ~24 hr oscillations in gene expression, physiological function, and behavior. Circadian clocks exist in almost every tissue and are thought to control tissue-specific gene expression and function, synchronized by the brain clock. Many disease states are associated with loss of circadian regulation. How and when circadian clocks fail during pathogenesis remains largely unknown because it is currently difficult to monitor tissue-specific clock function in intact organisms. Here, we developed a method to directly measure the transcriptional oscillation of distinct neuronal and peripheral clocks in live, intact Drosophila, which we term Locally Activatable BioLuminescence, or LABL. Using this method, we observed that specific neuronal and peripheral clocks exhibit distinct transcriptional properties. Loss of the receptor for PDF, a circadian neurotransmitter critical for the function of the brain clock, disrupts circadian locomotor activity but not all tissue-specific circadian clocks. We found that, while peripheral clocks in non-neuronal tissues were less stable after the loss of PDF signaling, they continued to oscillate. We also demonstrate that distinct clocks exhibit differences in their loss of oscillatory amplitude or their change in period, depending on their anatomical location, mutation, or fly age. Our results demonstrate that LABL is an effective tool that allows rapid, affordable, and direct real-time monitoring of individual clocks in vivo.


The daily rhythms in our lives are driven by biological mechanisms called circadian clocks. These biological clocks are protein machines found in almost every cell and organ of the body, in nearly all living things, from fungi and plants to fruit flies and humans. These clocks control 24-hour cycles of gene activity and behaviour, and are kept in-time by so-called 'master clocks' in the brain. Ideally, scientists would be able to observe how circadian clocks work in different parts of the brain in a living animal and track changes throughout the day, as the animal performs different behaviours. However, the tools that are currently available to study circadian clocks do not allow this. To overcome this difficulty, Johnstone et al. used fruit flies to develop a new method that allows scientists to measure the oscillations of the circadian clocks in the brain in real time. Circadian clocks are composed of proteins called 'transcription factors' that activate different genes throughout the day, producing different proteins at different times. Transcription factors control the activity of genes by binding to DNA sequences called 'promoters' and switching the genes regulated by these promoters on or off. Knowing this, Johnstone et al. engineered fruit flies to carry the gene that codes for a protein called luciferase, which emits light, and placed it under the control of the promoter for the period gene, a gene that is regulated by the circadian clock. To prevent all of the cells in the fly from producing luciferase any time the period promoter was active, Johnstone et al. placed a second gene between the promoter and the luciferase gene. This second gene contains 'stop' sequences that prevent luciferase from being produced as long as the second gene is present. Importantly, this gene can be genetically removed from specific cells in live flies, so only these cells will produce luciferase. When Johnstone et al. removed the second gene from specific cells in the fly brain that are involved in controlling behaviours related to the circadian clocks, these cells started emitting light in cycles that reproduced the activity of the circadian clocks. Thus, by monitoring how the brightness of luciferase changed throughout the day in these flies, Johnstone et al. were able to reveal how the circadian clocks work in different parts of the fly brain. They found that each clock had slightly different cycling lengths, suggesting that the clocks work differently in different parts of the brain to control behaviour. Interestingly, Johnstone et al. found that if a key gene responsible for communication between cells was mutated, the effects of the mutation also varied in different parts of the brain. This suggests that different clocks respond differently to communication cues. Additionally, the results showed that circadian clock activity also changed with age: older flies had weaker circadian behaviours ­ fewer changes in both behavioural and genetic activity levels between the day and night ­ than younger animals. Johnstone et al.'s approach makes it possible to track a living animal's circadian clocks in different parts of the brain and in different organs in real time without the need to dissect the animal. In the future, this method will help scientists understand the links between different circadian clocks, the genes associated with them, and the behaviours they control.


Assuntos
Relógios Circadianos , Proteínas de Drosophila , Animais , Drosophila melanogaster/fisiologia , Proteínas de Drosophila/genética , Proteínas de Drosophila/metabolismo , Relógios Biológicos/fisiologia , Ritmo Circadiano/genética , Drosophila/fisiologia , Relógios Circadianos/genética
16.
Curr Biol ; 32(22): 4869-4880.e4, 2022 Nov 21.
Artigo em Inglês | MEDLINE | ID: mdl-36265490

RESUMO

Aversive olfactory conditioning in Drosophila is a valuable model for elucidating the mechanism of associative learning. Much effort has centered around the role of neuroplasticity at the mushroom body (MB)-mushroom body output neuron (MBON) synapses in mapping odors to specific behaviors. By electrophysiological recordings from MB neurons, we discovered a form of input-timing-dependent plasticity at the incoming synapses from projection neurons that controls the efficacy of aversive olfactory memory formation. Importantly, this plasticity is facilitated by the neural activity of PPL1, the neuronal cluster that also modulates MB-MBON connections at the output stage of MB. Unlike the MB-MBON synapses that probably utilize dopamine D1-like receptors, this neuroplasticity is dependent on D2-like receptors that are expressed mainly by γ Kenyon cells noticeably in their somato-dendritic region. The D2-like receptors recruit voltage-gated calcium channels, leading to calcium influx in the soma and dendrites of γ neurons. Together, our results reveal a previously unrecognized synaptic component of the MB circuit architecture that not only could increase the salience of a conditioning odor but also couples the process of memory encoding and valency mapping to drive-associative learning.


Assuntos
Drosophila , Corpos Pedunculados , Animais , Corpos Pedunculados/fisiologia , Drosophila/fisiologia , Sinapses/fisiologia , Olfato/fisiologia , Condicionamento Clássico , Drosophila melanogaster/fisiologia
17.
Sci Signal ; 15(755): eabl6179, 2022 10 11.
Artigo em Inglês | MEDLINE | ID: mdl-36219683

RESUMO

Drosophila phototransduction is a model for signaling cascades that culminate in the activation of transient receptor potential (TRP) cation channels. TRP and TRPL are the canonical TRP (TRPC) channels that are regulated by light stimulation of rhodopsin and engagement of Gαq and phospholipase Cß (PLC). Lipid metabolite(s) generated downstream of PLC are essential for the activation of the TRPC channels in photoreceptor cells. We sought to identify the key lipids produced subsequent to PLC stimulation that contribute to channel activation. Here, using genetics, lipid analysis, and Ca2+ imaging, we found that light increased the amount of an abundant endocannabinoid, 2-linoleoyl glycerol (2-LG), in vivo. The increase in 2-LG amounts depended on the PLC and diacylglycerol lipase encoded by norpA and inaE, respectively. This endocannabinoid facilitated TRPC-dependent Ca2+ influx in a heterologous expression system and in dissociated ommatidia from compound eyes. Moreover, 2-LG and mechanical stimulation cooperatively activated TRPC channels in ommatidia. We propose that 2-LG is a physiologically relevant endocannabinoid that activates TRPC channels in photoreceptor cells.


Assuntos
Proteínas de Drosophila , Canais de Potencial de Receptor Transitório , Animais , Cátions/metabolismo , Drosophila/fisiologia , Proteínas de Drosophila/genética , Proteínas de Drosophila/metabolismo , Endocanabinoides/metabolismo , Endocanabinoides/farmacologia , Glicerol/metabolismo , Luz , Lipase Lipoproteica/genética , Lipase Lipoproteica/metabolismo , Fosfolipases/metabolismo , Células Fotorreceptoras de Invertebrados/metabolismo , Rodopsina/metabolismo , Canais de Cátion TRPC/genética , Canais de Cátion TRPC/metabolismo , Canais de Potencial de Receptor Transitório/genética , Canais de Potencial de Receptor Transitório/metabolismo
18.
Neuron ; 110(19): 3058-3060, 2022 10 05.
Artigo em Inglês | MEDLINE | ID: mdl-36202088

RESUMO

Glia-neuronal interplay is critical for circadian regulation of physiology and behavior. In this issue of Neuron, Vaughen et al. identify daily variations of glycosphingolipids that depend on glia and whose disruption alters proteostasis and daily structural plasticity of Drosophila circadian circuits.


Assuntos
Proteínas de Drosophila , Glicoesfingolipídeos , Animais , Encéfalo/fisiologia , Ritmo Circadiano/fisiologia , Drosophila/fisiologia , Proteínas de Drosophila/metabolismo , Homeostase , Neuroglia/fisiologia , Plasticidade Neuronal/fisiologia , Neurônios/fisiologia
19.
J Evol Biol ; 35(11): 1548-1557, 2022 11.
Artigo em Inglês | MEDLINE | ID: mdl-36196885

RESUMO

Sex-based differences in physiological traits may be influenced by both evolutionary and environmental factors. Here we used male and female flies from >80 Drosophila species reared under common conditions to examine variance in a number of physiological traits including size, starvation, desiccation and thermal tolerance. Sex-based differences for desiccation and starvation resistance were comparable in magnitude to those for size, with females tending to be relatively more resistant than males. In contrast thermal resistance showed low divergence between the sexes. Phylogenetic signal was detected for measures of divergence between the sexes, such that species from the Sophophora clade showed larger differences between the sexes than species from the Drosophila clade. We also found that sex-based differences in desiccation resistance, body size and starvation resistance were weakly associated with climate (annual mean temperature/precipitation seasonality) but the direction and association with environment depended on phylogenetic position. The results suggest that divergence between the sexes can be linked to environmental factors, while an association with phylogeny suggests sex-based differences persist over long evolutionary time-frames.


Assuntos
Drosophila , Inanição , Animais , Feminino , Masculino , Drosophila/fisiologia , Filogenia , Diferenciação Sexual , Dessecação
20.
Elife ; 112022 10 27.
Artigo em Inglês | MEDLINE | ID: mdl-36300621

RESUMO

Natural vision is dynamic: as an animal moves, its visual input changes dramatically. How can the visual system reliably extract local features from an input dominated by self-generated signals? In Drosophila, diverse local visual features are represented by a group of projection neurons with distinct tuning properties. Here, we describe a connectome-based volumetric imaging strategy to measure visually evoked neural activity across this population. We show that local visual features are jointly represented across the population, and a shared gain factor improves trial-to-trial coding fidelity. A subset of these neurons, tuned to small objects, is modulated by two independent signals associated with self-movement, a motor-related signal, and a visual motion signal associated with rotation of the animal. These two inputs adjust the sensitivity of these feature detectors across the locomotor cycle, selectively reducing their gain during saccades and restoring it during intersaccadic intervals. This work reveals a strategy for reliable feature detection during locomotion.


Assuntos
Drosophila , Percepção de Movimento , Animais , Drosophila/fisiologia , Locomoção/fisiologia , Visão Ocular , Neurônios/fisiologia , Interneurônios , Percepção de Movimento/fisiologia
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...