Sodium present in NaCl is a fundamental nutrient required for many physiological processes. In an... more Sodium present in NaCl is a fundamental nutrient required for many physiological processes. In animals including Drosophila low-salt concentrations induce attraction and high-salt concentrations evoke aversive behavior. Although high salt detection pathways have been studied in great details but mechanisms that regulate high salt consumption in animals are largely undetermined. We looked into the neural mechanisms of high NaCl consumption in adult Drosophila by which flies modify their acceptance of high salt as a function of diet where a long-term high-salt exposure increases taste sensitivity of pharyngeal LSO neurons and enhance high salt intake. Exposing flies to high NaCl diet for three days show decline in high salt aversion under starvation. Additionally, genetic suppression of LSO pharyngeal neurons in high NaCl fed flies inhibit excessive salt intake. We observed this modulation requires functional LSO neurons and a starvation state or dopamine. Multiple independent taste r...
Nutrient-sensing mechanisms in animals’ sense available nutrients to generate a physiological reg... more Nutrient-sensing mechanisms in animals’ sense available nutrients to generate a physiological regulatory response involving absorption, digestion, and regulation of food intake and to maintain glucose and energy homeostasis. During nutrient sensing via the gastrointestinal tract, nutrients interact with receptors on the enteroendocrine cells in the gut, which in return respond by secreting various hormones. Sensing of nutrients by the gut plays a critical role in transmitting food-related signals to the brain and other tissues informing the composition of ingested food to digestive processes. These signals modulate feeding behaviors, food intake, metabolism, insulin secretion, and energy balance. The increasing significance of fly genetics with the availability of a vast toolbox for studying physiological function, expression of chemosensory receptors, and monitoring the gene expression in specific cells of the intestine makes the fly gut the most useful tissue for studying the nutr...
Background: Members of the canonical Transient Receptor Potential (TRPC) class of cationic channe... more Background: Members of the canonical Transient Receptor Potential (TRPC) class of cationic channels function downstream of Gaq and PLCb in Drosophila photoreceptors for transducing visual stimuli. Gaq has recently been implicated in olfactory sensing of carbon dioxide (CO2) and other odorants. Here we investigated the role of PLCb and TRPC channels for sensing CO2 in Drosophila. Methodology/Principal Findings: Through behavioral assays it was demonstrated that Drosophila mutants for plc21c, trp and trpl have a reduced sensitivity for CO2. Immuno-histochemical staining for TRP, TRPL and TRPc indicates that all three channels are expressed in Drosophila antennae including the sensory neurons that express CO2 receptors. Electrophysiological recordings obtained from the antennae of protein null alleles of TRP (trp343) and TRPL (trpl302), showed that the sensory response to multiple concentrations of CO2 was reduced. However, trpl 302; trp343 double mutants still have a residual response...
Introduction: Sugar is the main source of energy for nearly all animals. However, consumption of ... more Introduction: Sugar is the main source of energy for nearly all animals. However, consumption of a high amount of sugars can lead to many metabolic disorders hence, balancing calorie intake in the form of sugar is required. Various herbs are in use to control body weight, cure diabetes and control elevated blood sugar levels. One such herb is Gymnema sylvestre commonly called Gurmar (destroyer of sugar). Gurmar selectively inhibits sugar sensation by mechanisms that are still elusive. Objectives: The primary objective of this study is to understand the effect of gurmar on sweet taste feeding behaviour in insects using the invertebrate model system Drosophila melanogaster. Methods: For this study, we used feeding assays, spectrophotometry and Proboscis Extension Reflex (PER) assay to determine how flies detect gurmar. Additionally, life span analysis, egg-laying behaviour and developmental profiles were used to probe the role of gurmar on the overall health of the flies. During the w...
Fruit fly, Drosophila melanogaster is a most powerful animal model for exploring fundamental biol... more Fruit fly, Drosophila melanogaster is a most powerful animal model for exploring fundamental biological processes and modeling molecular and cellular aspects of human diseases. It provides the flexibility and tool box with which scientists can experimentally manipulate and study behavior as well as gene expression in specific, defined population of cells in their normal tissue contexts. The utility and increasing value of a sophisticated genetic system of flies, the tool box available for studying physiological function, functional imaging, neural circuitry from gut to brain, taste receptors expression and controlling gene expression by determining the specific cells in the intestine, makes fly gut the most useful tissue for studying the regulation of feeding behavior under changing internal state. To understand the intestine and its connectivity with the brain, Drosophila has proved an ideal model organism for studying gut brain axis aspects of human metabolic diseases. Various mar...
When there is a perturbation in the balance between hunger and satiety, food intake gets mis-regu... more When there is a perturbation in the balance between hunger and satiety, food intake gets mis-regulated leading to excessive or insufficient eating. In humans, abnormal nutrient consumption causes metabolic conditions like obesity, diabetes, and eating disorders affecting overall health. Despite this burden on society, we currently lack enough knowledge about the neuronal circuits that regulate appetite and taste perception. How specific taste neuronal circuits influence feeding behaviours is still an under explored area in neurobiology. The taste information present at the periphery must be processed by the central circuits for the final behavioural output. Identification and understanding of central neural circuitry regulating taste behaviour and its modulation by physiological changes with regard to internal state is required to understand the neural basis of taste preference. Simple invertebrate model organisms like Drosophila melanogaster can sense the same taste stimuli as mamm...
The world is currently witnessing a severe health crisis of its time. Everyone is juggling and st... more The world is currently witnessing a severe health crisis of its time. Everyone is juggling and struggling to fight a viral disease named Covid-19 (Corona virus disease 2019) caused by SARS-CoV-2 (Severe Acute Respiratory Syndrome Coronavirus 2). The genome of newly identified virus is less than 30,000 letters long where pathogenesis involve from being asymptomatic to deadly in all age groups. Almost everybody is at a grave risk in such an unpredictable scenario where range of symptoms are so variable from people to people making this pandemic a threat to human race.
Sachin Kumar1 and Pinky Kain2* 1Director/Founder, Viresco Technologies LLP, Roorkee, Uttarakhand,... more Sachin Kumar1 and Pinky Kain2* 1Director/Founder, Viresco Technologies LLP, Roorkee, Uttarakhand, India 2Principal Investigator/DBT Welcome Trust India Alliance Fellow, Laboratory of Neurogenetics, Regional Centre for Biotechnology, NCR Biotech Science Cluster, Faridabad, Haryana, India *Corresponding Author: Pinky Kain, Principal Investigator/DBT Welcome Trust India Alliance Fellow, Laboratory of Neurogenetics, Regional Centre for Biotechnology, NCR Biotech Science Cluster, Faridabad, Haryana, India. Short Communication
Mechanisms by which G-protein-coupled odorant receptors transduce information in insects still ne... more Mechanisms by which G-protein-coupled odorant receptors transduce information in insects still need elucidation. We show that mutations in the Drosophila gene for G(q)alpha (dgq) significantly reduce both the amplitude of the field potentials recorded from the whole antenna in responses to odorants as well as the frequency of evoked responses of individual sensory neurons. This requirement for G(q)alpha is for adult function and not during antennal development. Conversely, brief expression of a dominant-active form of G(q)alpha in adults leads to enhanced odor responses. To understand signaling downstream of G(q)alpha in olfactory sensory neurons, genetic interactions of dgq were tested with mutants in genes known to affect phospholipid signaling. dgq mutant phenotypes were further enhanced by mutants in a PLCbeta (phospholipase Cbeta) gene, plc21C. Interestingly although, the olfactory phenotype of mutant alleles of diacylglycerol kinase (rdgA) was rescued by dgq mutant alleles. Our results suggest that G(q)alpha-mediated olfactory transduction in Drosophila requires a phospholipid second messenger the levels of which are regulated by a cycle of phosphatidylinositol 1,4-bisphosphate breakdown and regeneration.
The widely used insect repellent DEET has a limited spatial zone of protection, requiring it to b... more The widely used insect repellent DEET has a limited spatial zone of protection, requiring it to be applied over all exposed areas of skin. Identification of insect DEET-sensing neurons expressing a highly conserved Ionotropic receptor, Ir40a, provides an opportunity to identify new structural classes of volatile agonists as potential spatial repellents. By imaging the activity of the Ir40a+ neurons in D. melanogaster expressing the calcium sensitive GCaMP3 protein, we identify a strong agonist, 4-methylpiperidine, with a much higher vapor pressure than DEET. Behavioral testing reveals that 4-methylpiperidine repels Aedes aegypti, which is consistent with our model that Ir40a marks a conserved innate aversive pathway. Using a spatial repellency assay we demonstrate that 4-methylpiperidine applied to one part of the hand repels mosquitoes on another part effectively, whereas DEET cannot do so. Using orco mutant A. aegypti we demonstrate that avoidance to 4-methypiperidine is not depen...
Sodium present in NaCl is a fundamental nutrient required for many physiological processes. In an... more Sodium present in NaCl is a fundamental nutrient required for many physiological processes. In animals including Drosophila low-salt concentrations induce attraction and high-salt concentrations evoke aversive behavior. Although high salt detection pathways have been studied in great details but mechanisms that regulate high salt consumption in animals are largely undetermined. We looked into the neural mechanisms of high NaCl consumption in adult Drosophila by which flies modify their acceptance of high salt as a function of diet where a long-term high-salt exposure increases taste sensitivity of pharyngeal LSO neurons and enhance high salt intake. Exposing flies to high NaCl diet for three days show decline in high salt aversion under starvation. Additionally, genetic suppression of LSO pharyngeal neurons in high NaCl fed flies inhibit excessive salt intake. We observed this modulation requires functional LSO neurons and a starvation state or dopamine. Multiple independent taste r...
Nutrient-sensing mechanisms in animals’ sense available nutrients to generate a physiological reg... more Nutrient-sensing mechanisms in animals’ sense available nutrients to generate a physiological regulatory response involving absorption, digestion, and regulation of food intake and to maintain glucose and energy homeostasis. During nutrient sensing via the gastrointestinal tract, nutrients interact with receptors on the enteroendocrine cells in the gut, which in return respond by secreting various hormones. Sensing of nutrients by the gut plays a critical role in transmitting food-related signals to the brain and other tissues informing the composition of ingested food to digestive processes. These signals modulate feeding behaviors, food intake, metabolism, insulin secretion, and energy balance. The increasing significance of fly genetics with the availability of a vast toolbox for studying physiological function, expression of chemosensory receptors, and monitoring the gene expression in specific cells of the intestine makes the fly gut the most useful tissue for studying the nutr...
Background: Members of the canonical Transient Receptor Potential (TRPC) class of cationic channe... more Background: Members of the canonical Transient Receptor Potential (TRPC) class of cationic channels function downstream of Gaq and PLCb in Drosophila photoreceptors for transducing visual stimuli. Gaq has recently been implicated in olfactory sensing of carbon dioxide (CO2) and other odorants. Here we investigated the role of PLCb and TRPC channels for sensing CO2 in Drosophila. Methodology/Principal Findings: Through behavioral assays it was demonstrated that Drosophila mutants for plc21c, trp and trpl have a reduced sensitivity for CO2. Immuno-histochemical staining for TRP, TRPL and TRPc indicates that all three channels are expressed in Drosophila antennae including the sensory neurons that express CO2 receptors. Electrophysiological recordings obtained from the antennae of protein null alleles of TRP (trp343) and TRPL (trpl302), showed that the sensory response to multiple concentrations of CO2 was reduced. However, trpl 302; trp343 double mutants still have a residual response...
Introduction: Sugar is the main source of energy for nearly all animals. However, consumption of ... more Introduction: Sugar is the main source of energy for nearly all animals. However, consumption of a high amount of sugars can lead to many metabolic disorders hence, balancing calorie intake in the form of sugar is required. Various herbs are in use to control body weight, cure diabetes and control elevated blood sugar levels. One such herb is Gymnema sylvestre commonly called Gurmar (destroyer of sugar). Gurmar selectively inhibits sugar sensation by mechanisms that are still elusive. Objectives: The primary objective of this study is to understand the effect of gurmar on sweet taste feeding behaviour in insects using the invertebrate model system Drosophila melanogaster. Methods: For this study, we used feeding assays, spectrophotometry and Proboscis Extension Reflex (PER) assay to determine how flies detect gurmar. Additionally, life span analysis, egg-laying behaviour and developmental profiles were used to probe the role of gurmar on the overall health of the flies. During the w...
Fruit fly, Drosophila melanogaster is a most powerful animal model for exploring fundamental biol... more Fruit fly, Drosophila melanogaster is a most powerful animal model for exploring fundamental biological processes and modeling molecular and cellular aspects of human diseases. It provides the flexibility and tool box with which scientists can experimentally manipulate and study behavior as well as gene expression in specific, defined population of cells in their normal tissue contexts. The utility and increasing value of a sophisticated genetic system of flies, the tool box available for studying physiological function, functional imaging, neural circuitry from gut to brain, taste receptors expression and controlling gene expression by determining the specific cells in the intestine, makes fly gut the most useful tissue for studying the regulation of feeding behavior under changing internal state. To understand the intestine and its connectivity with the brain, Drosophila has proved an ideal model organism for studying gut brain axis aspects of human metabolic diseases. Various mar...
When there is a perturbation in the balance between hunger and satiety, food intake gets mis-regu... more When there is a perturbation in the balance between hunger and satiety, food intake gets mis-regulated leading to excessive or insufficient eating. In humans, abnormal nutrient consumption causes metabolic conditions like obesity, diabetes, and eating disorders affecting overall health. Despite this burden on society, we currently lack enough knowledge about the neuronal circuits that regulate appetite and taste perception. How specific taste neuronal circuits influence feeding behaviours is still an under explored area in neurobiology. The taste information present at the periphery must be processed by the central circuits for the final behavioural output. Identification and understanding of central neural circuitry regulating taste behaviour and its modulation by physiological changes with regard to internal state is required to understand the neural basis of taste preference. Simple invertebrate model organisms like Drosophila melanogaster can sense the same taste stimuli as mamm...
The world is currently witnessing a severe health crisis of its time. Everyone is juggling and st... more The world is currently witnessing a severe health crisis of its time. Everyone is juggling and struggling to fight a viral disease named Covid-19 (Corona virus disease 2019) caused by SARS-CoV-2 (Severe Acute Respiratory Syndrome Coronavirus 2). The genome of newly identified virus is less than 30,000 letters long where pathogenesis involve from being asymptomatic to deadly in all age groups. Almost everybody is at a grave risk in such an unpredictable scenario where range of symptoms are so variable from people to people making this pandemic a threat to human race.
Sachin Kumar1 and Pinky Kain2* 1Director/Founder, Viresco Technologies LLP, Roorkee, Uttarakhand,... more Sachin Kumar1 and Pinky Kain2* 1Director/Founder, Viresco Technologies LLP, Roorkee, Uttarakhand, India 2Principal Investigator/DBT Welcome Trust India Alliance Fellow, Laboratory of Neurogenetics, Regional Centre for Biotechnology, NCR Biotech Science Cluster, Faridabad, Haryana, India *Corresponding Author: Pinky Kain, Principal Investigator/DBT Welcome Trust India Alliance Fellow, Laboratory of Neurogenetics, Regional Centre for Biotechnology, NCR Biotech Science Cluster, Faridabad, Haryana, India. Short Communication
Mechanisms by which G-protein-coupled odorant receptors transduce information in insects still ne... more Mechanisms by which G-protein-coupled odorant receptors transduce information in insects still need elucidation. We show that mutations in the Drosophila gene for G(q)alpha (dgq) significantly reduce both the amplitude of the field potentials recorded from the whole antenna in responses to odorants as well as the frequency of evoked responses of individual sensory neurons. This requirement for G(q)alpha is for adult function and not during antennal development. Conversely, brief expression of a dominant-active form of G(q)alpha in adults leads to enhanced odor responses. To understand signaling downstream of G(q)alpha in olfactory sensory neurons, genetic interactions of dgq were tested with mutants in genes known to affect phospholipid signaling. dgq mutant phenotypes were further enhanced by mutants in a PLCbeta (phospholipase Cbeta) gene, plc21C. Interestingly although, the olfactory phenotype of mutant alleles of diacylglycerol kinase (rdgA) was rescued by dgq mutant alleles. Our results suggest that G(q)alpha-mediated olfactory transduction in Drosophila requires a phospholipid second messenger the levels of which are regulated by a cycle of phosphatidylinositol 1,4-bisphosphate breakdown and regeneration.
The widely used insect repellent DEET has a limited spatial zone of protection, requiring it to b... more The widely used insect repellent DEET has a limited spatial zone of protection, requiring it to be applied over all exposed areas of skin. Identification of insect DEET-sensing neurons expressing a highly conserved Ionotropic receptor, Ir40a, provides an opportunity to identify new structural classes of volatile agonists as potential spatial repellents. By imaging the activity of the Ir40a+ neurons in D. melanogaster expressing the calcium sensitive GCaMP3 protein, we identify a strong agonist, 4-methylpiperidine, with a much higher vapor pressure than DEET. Behavioral testing reveals that 4-methylpiperidine repels Aedes aegypti, which is consistent with our model that Ir40a marks a conserved innate aversive pathway. Using a spatial repellency assay we demonstrate that 4-methylpiperidine applied to one part of the hand repels mosquitoes on another part effectively, whereas DEET cannot do so. Using orco mutant A. aegypti we demonstrate that avoidance to 4-methypiperidine is not depen...
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