scholarly journals Electrophysiological and Morphological Characterization of Identified Motor Neurons in the Drosophila Third Instar Larva Central Nervous System

2004 ◽  
Vol 91 (5) ◽  
pp. 2353-2365 ◽  
Author(s):  
James C. Choi ◽  
Demian Park ◽  
Leslie C. Griffith
Keyword(s):  
Motor Neurons ◽  
Instar Larva ◽  
Morphological Characterization ◽  
Genetic Identification ◽  
Display Type ◽  
Voltage Sensitivity ◽  
Ventral Ganglion ◽  
Larval Stages ◽  
Electrophysiological Recordings ◽  
Cell Recording

We have used dye fills and electrophysiological recordings to identify and characterize a cluster of motor neurons in the third instar larval ventral ganglion. This cluster of neurons is similar in position to the well-studied embryonic RP neurons. Dye fills of larval dorsomedial neurons demonstrate that individual neurons within the cluster can be reproducibly identified by observing their muscle targets and bouton morphology. The terminal targets of these five neurons are body wall muscles 6/7, 1, 14, and 30 and the intersegmental nerve (ISN) terminal muscles (1, 2, 3, 4, 9, 10, 19, 20). All cells except the ISN neuron, which has a type Is ending, display type Ib boutons. Two of these neurons appear to be identical to the embryonic RP3 and aCC cells, which define the most proximal and distal innervations within a hemisegment. The targets of the other neurons in the larval dorsomedial cluster do not correspond to embryonic targets of the neurons in the RP cluster, suggesting rewiring of this circuit during early larval stages. Electrophysiological studies of the five neurons in current clamp revealed that type Is neurons have a longer delay in the appearance of the first spike compared with type Ib neurons. Genetic, biophysical, and pharmacological studies in current and voltage clamp show this delay is controlled by the kinetics and voltage sensitivity of inactivation of a current whose properties suggest that it may be the Shal IA current. The combination of genetic identification and whole cell recording allows us to directly explore the cellular substrates of neural and locomotor behavior in an intact system.

scholarly journals Observations on the predatory potential of Lutzia fuscana on Aedes aegypti larvae: implications for biological control (Diptera: Culicidae)

2016 ◽  
Vol 48 (2) ◽  
pp. 137
Author(s):  
Soujita Pramanik ◽  
Sampa Banerjee ◽  
Soumyajit Banerjee ◽  
Goutam K. Saha ◽  
Gautam Aditya
Keyword(s):  
Biological Control ◽  
Aedes Aegypti ◽  
Biological Control Agent ◽  
Instar Larva ◽  
Control Agent ◽  
The Body ◽  
Larval Habitats ◽  
Larval Stages ◽  
Augmentative Release ◽  
Predatory Potential

Among the natural predators, larval stages of the mosquito <em>Lutzia fuscana (</em>Wiedemann, 1820) (Diptera: Culicidae) bear potential as a biological control agent of mosquitoes. An estimation of the predatory potential of the larva of <em>L. fuscana</em> against the larva of the dengue vector <em>Aedes aegypti</em> (Linnaeus, 1762) (Diptera: Culicidae) was made to highlight its use in vector management. Laboratory experiments revealed that the larva of<em> L</em>. <em>fuscana</em> consumes 19 to 24 <em>A. aegypti</em> larvae per day, during its tenure as IV instar larva. The consumption of <em>A. aegypti</em> larvae was proportionate to the body length (BL) and body weight (BW) of the predatory larva<em> L. fuscana</em> as depicted through the logistic regressions: y = 1 / (1 + exp(-(-2.09 + 0.35*BL))) and y = 1 / (1 + exp(-(0.4+ 0.06*BW))). While the prey consumption remained comparable among the days, the net weight gained by the <em>L</em>. <em>fuscana</em> larva showed a decreasing trend with the age. On the basis of the results, it is apparent that the larva of the mosquito <em>L. fuscana</em> can be used in the regulation of the mosquito <em>A. aegypti</em> through augmentative release, particularly, in the smaller mosquito larval habitats.

Voltage dependence of conductance changes evoked by glycine release in the zebrafish brain

1995 ◽  
Vol 73 (6) ◽  
pp. 2404-2412 ◽  
Author(s):  
P. Legendre ◽  
H. Korn
Keyword(s):  
Voltage Dependence ◽  
Reversal Potential ◽  
Voltage Sensitivity ◽  
M Cell ◽  
Open Probability ◽  
Similar Time ◽  
Whole Cell ◽  
Glycine Release ◽  
Cell Recording ◽  
Voltage Dependent

1. The kinetics and mechanisms underlying the voltage dependence of inhibitory postsynaptic currents (IPSCs) recorded in the Mauthner cell (M cell) were investigated in the isolated medulla of 52-h-old zebrafish larvae, with the use of whole cell and outside-out patch-clamp recordings. 2. Spontaneous miniature IPSCs (mIPSCs) were recorded in the presence of 10(-6) M tetrodotoxin (TTX), 10 mM MgCl2, and 0.1 mM [CaCl2]o. Depolarizing the cell from -50 to +50 mV did not evoke any significant change in the distribution of mIPSC amplitudes, whereas synaptic currents were prolonged at positive voltages. The average decay time constant was increased twofold at +50 mV. 3. The voltage dependence of the kinetics of glycine-activated channels was first investigated during whole cell recording experiments. Currents evoked by voltage steps in the presence of glycine (50 microM) were compared with those obtained without glycine. The increase in chloride conductance (gCl-) evoked by glycine was time and voltage dependent. Inactivation and reactivation of the chloride current were observed during voltage pulses from 0 to -50 mV and from -50 to 0 mV, respectively, and they occurred with similar time constants (2-3 s). During glycine application, voltage-ramp analysis revealed a shift in the reversal potential (ECl-) occurring at all [Cl-]i tested. 4. The basis of the voltage sensitivity of glycine-evoked gCl- was first analyzed by measuring the relative changes in the total open probability (NPo) of glycine-activated channels with voltage.(ABSTRACT TRUNCATED AT 250 WORDS)

Analysis of decreased conductance serotonergic response in Aplysia ink motor neurons

1985 ◽  
Vol 53 (2) ◽  
pp. 590-602 ◽  
Author(s):  
J. P. Walsh ◽  
J. H. Byrne
Keyword(s):  
Cell Body ◽  
Motor Neurons ◽  
Potassium Conductance ◽  
Membrane Conductance ◽  
Resting Potential ◽  
Slow Inward Current ◽  
Equilibrium Potential ◽  
Voltage Sensitivity ◽  
Inward Current ◽  
Bath Application

Micropressure ejection of serotonin (5-hydroxytryptamine, 5-HT) produced excitatory responses in the L14 ink motor neurons of Aplysia that depended on the site of application. Ejection of 5-HT onto the cell body produced a slow response that showed variability in voltage sensitivity between preparations. In contrast, ejection of 5-HT onto the neuropil underneath the cell body produced a response whose amplitude was consistently a linear function of the holding potential, reversing near the predicted potassium equilibrium potential. Subsequent analyses focused on this second response. The neuropil response induced by 5-HT had a linear current-voltage relationship (reversing at ca. -80 mV), was associated with a decrease in input conductance, and was sensitive to changes in the concentration of extracellular K+. Serotonin application in artificial seawater (ASW) containing 30 mM K+ produced a response that reversed close to the altered Nernst potential for K+. The 5-HT response did not appear to be due to secondary activation of interneurons or to depend primarily on extracellular Ca2+, since ejection of 5-HT onto cells bathed in ASW containing 30 mM Co2+ produced responses comparable to, although somewhat attenuated from, those observed in ASW. Serotonin responses similar to those produced in ASW were obtained after perfusing the ganglion with ASW containing Co2+, 4-aminopyridine (4-AP), and tetraethylammonium (TEA). This suggests that the 5-HT-sensitive current is separate from the Ca2+-activated, fast, and delayed rectifying K+ currents. The 5-HT response appeared to be mediated by changes in levels of cAMP. Bath application of the phosphodiesterase inhibitors IBMX (3-isobutyl-1-methylxanthine) or Ro 20-1724, or the adenylate cyclase activator forskolin mimicked the 5-HT response by producing a slow inward current associated with a decrease in membrane conductance. Alteration of cellular cAMP metabolism modulated the response to 5-HT. Exposure of the ganglion to low concentrations of either Ro 20-1724 or forskolin potentiated the 5-HT response. Higher concentrations of these agents largely blocked the response to subsequent 5-HT applications. Bath application of the 8-bromo derivative of either cAMP or cGMP produced a slow inward current associated with a decrease in membrane conductance in cells voltage clamped at the resting potential. Responses to 5-HT were blocked, however, after exposure to 8-bromo-cAMP, but not to 8-bromo-cGMP. These results suggest that 5-HT produces a voltage-independent decrease in a steady-state potassium conductance that may be mediated by cAMP.(ABSTRACT TRUNCATED AT 400 WORDS)

scholarly journals Optimized Protocol to Generate Spinal Motor Neuron Cells from Induced Pluripotent Stem Cells from Charcot Marie Tooth Patients

2020 ◽  
Vol 10 (7) ◽  
pp. 407
Author(s):  
Pierre-Antoine Faye ◽  
Nicolas Vedrenne ◽  
Federica Miressi ◽  
Marion Rassat ◽  
Sergii Romanenko ◽  
...  
Keyword(s):  
Stem Cells ◽  
Induced Pluripotent Stem Cells ◽  
Motor Neurons ◽  
Pluripotent Stem Cells ◽  
Charcot Marie Tooth ◽  
Charcot Marie Tooth Disease ◽  
Spinal Motor ◽  
Electrophysiological Recordings ◽  
Induced Pluripotent

Modelling rare neurogenetic diseases to develop new therapeutic strategies is highly challenging. The use of human-induced pluripotent stem cells (hiPSCs) is a powerful approach to obtain specialized cells from patients. For hereditary peripheral neuropathies, such as Charcot–Marie–Tooth disease (CMT) Type II, spinal motor neurons (MNs) are impaired but are very difficult to study. Although several protocols are available to differentiate hiPSCs into neurons, their efficiency is still poor for CMT patients. Thus, our goal was to develop a robust, easy, and reproducible protocol to obtain MNs from CMT patient hiPSCs. The presented protocol generates MNs within 20 days, with a success rate of 80%, using specifically chosen molecules, such as Sonic Hedgehog or retinoic acid. The timing and concentrations of the factors used to induce differentiation are crucial and are given hereby. We then assessed the MNs by optic microscopy, immunocytochemistry (Islet1/2, HB9, Tuj1, and PGP9.5), and electrophysiological recordings. This method of generating MNs from CMT patients in vitro shows promise for the further development of assays to understand the pathological mechanisms of CMT and for drug screening.

scholarly journals Immunofluorescence and image analysis pipeline for Drosophila motor neurons

2019 ◽  
Vol 4 (1) ◽  
Author(s):  
Jeremy R Brown ◽  
Chanpasith Phongthachit ◽  
Mikolaj J Sulkowski
Keyword(s):  
Image Analysis ◽  
Motor Neurons ◽  
Background Subtraction ◽  
Genetic Model ◽  
Automated Image Analysis ◽  
Ventral Ganglion ◽  
Pixel Intensity ◽  
Axon Terminals ◽  
The Central Nervous System ◽  
Motor Nuclei

Abstract The neuromuscular junction (NMJ) of larval Drosophila is widely used as a genetic model for basic neuroscience research. The presynaptic side of the NMJ is formed by axon terminals of motor neurons, the soma of which reside in the ventral ganglion of the central nervous system (CNS). Here we describe a streamlined protocol for dissection and immunostaining of the Drosophila CNS and NMJ that allows processing of multiple genotypes within a single staining tube. We also present a computer script called Automated Image Analysis with Background Subtraction which facilitates identification of motor nuclei, quantification of pixel intensity, and background subtraction. Together, these techniques provide a pipeline for neuroscientists to compare levels of different biomolecules in motor nuclei. We conclude that these methods should be adaptable to a variety of different cell and tissue types for the improvement of efficiency, reproducibility, and throughput during data quantification.

scholarly journals Micromorphology of egg and larva of Eristalis fratercula, with an updated key of Eristalis species with known third instar larvae (Diptera: Syrphidae)

2017 ◽  
Vol 57 (1) ◽  
pp. 215-227 ◽  
Author(s):  
Andrés Campoy ◽  
Celeste Pérez-Bañón ◽  
Tore R. Nielsen ◽  
Santos Rojo
Keyword(s):  
Electron Microscopy ◽  
Instar Larva ◽  
Liquid Media ◽  
Larval Stages ◽  
The Third ◽  
Morphological Studies ◽  
The Common ◽  
Third Instar Larva ◽  
Cryo Scanning Electron Microscopy ◽  
Scanning Electron

Abstract The flower- or hoverflies (Syrphidae) and particularly the subfamily Eristalinae, are known by their importance as pollinators in both natural and agro-ecosystems. Similar to other saprophagous eristalines, the larvae of Eristalis Latreille, 1804 are characterized by an elongated anal segment and a telescopic breathing tube. These features have given them the common name of rat-tailed maggots and allow them to develop in liquid or semi-liquid media loaded with decaying organic material. This paper presents the first description of the egg and the third-instar larva of the boreal species Eristalis fratercula (Zetterstedt, 1838). Morphological studies are presented based on cryo-scanning electron microscopy (cryo-SEM). After comparison with all other known species of the genus Eris-talis with described preimaginal morphology, we conclude that main diagnostic character of E. fratercula is the presence of long branched spicules located in the upper margin on the lateral lips. Finally, we provide an updated key that includes the 15 Eristalis species whose third larval stages have already been described.

scholarly journals Temperature and Photoperiodic Response of Diapause Induction in Anastatus japonicus, an Egg Parasitoid of Stink Bugs

Insects ◽  
2021 ◽  
Vol 12 (10) ◽  
pp. 872
Author(s):  
Can Zhao ◽  
Yi Guo ◽  
Zixin Liu ◽  
Yue Xia ◽  
Yuyan Li ◽  
...  
Keyword(s):  
Biological Control Agent ◽  
Developmental Regulation ◽  
Exposure Period ◽  
Instar Larva ◽  
Egg Parasitoid ◽  
Control Agent ◽  
Photoperiodic Response ◽  
Stink Bugs ◽  
Larval Stages ◽  
Long Term Storage

Anastatus japonicus Ashmead is a widely used biological control agent against stink bugs that can be successfully reared using the large eggs of the Chinese silkworm. In this study, environmental factors responsible for the induction of diapause in A. japonicus were investigated on host eggs of the Chinese silkworm. A. japonicus exhibited a facultative, mature larval diapause within its host eggs. Second–third instar larva are the most sensitive stages to diapause stimuli. The accumulation of diapause stimuli during all the larval stages maximized the diapause response. A short photoperiod of 10L:14D and temperature of 17 °C led to the occurrence of the highest diapause response, while a long photoperiod (14L:10D) and low temperatures (11 and 14 °C) prevented the diapause. A specific exposure period was required to reach high diapause incidence. Diapausing mature larvae had a significantly higher survival rate after 180 days storage at 10 °C than that of nondiapausing mature larvae. Taken together, results suggest methods that could be exploited in the developmental regulation, field-release pretreatment technology, and long-term storage of A. japonicus.

scholarly journals Responses of cerebellar Purkinje cells during fictive optomotor behavior in larval zebrafish

2016 ◽  
Vol 116 (5) ◽  
pp. 2067-2080 ◽  
Author(s):  
Karina Scalise ◽  
Takashi Shimizu ◽  
Masahiko Hibi ◽  
Nathaniel B. Sawtell
Keyword(s):  
Purkinje Cells ◽  
Climbing Fiber ◽  
Visual Responses ◽  
Optomotor Response ◽  
General Role ◽  
Larval Stages ◽  
Larval Zebrafish ◽  
Electrophysiological Recordings ◽  
Cerebellar Purkinje Cells ◽  
Climbing Fiber Responses

Although most studies of the cerebellum have been conducted in mammals, cerebellar circuitry is highly conserved across vertebrates, suggesting that studies of simpler systems may be useful for understanding cerebellar function. The larval zebrafish is particularly promising in this regard because of its accessibility to optical monitoring and manipulations of neural activity. Although several studies suggest that the cerebellum plays a role in behavior at larval stages, little is known about the signals conveyed by particular classes of cerebellar neurons. Here we use electrophysiological recordings to characterize subthreshold, simple spike, and climbing fiber responses in larval zebrafish Purkinje cells in the context of the fictive optomotor response (OMR)—a paradigm in which fish adjust motor output to stabilize their virtual position relative to a visual stimulus. Although visual responses were prominent in Purkinje cells, they lacked the direction or velocity sensitivity that would be expected for controlling the OMR. On the other hand, Purkinje cells exhibited strong responses during fictive swim bouts. Temporal characteristics of these responses are suggestive of a general role for the larval zebrafish cerebellum in controlling swimming. Climbing fibers encoded both visual and motor signals but did not appear to encode signals that could be used to adjust OMR gain, such as retinal slip. Finally, the observation of diverse relationships between simple spikes and climbing fiber responses in individual Purkinje cells highlights the importance of distinguishing between these two types of activity in calcium imaging experiments.

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