Understanding peripheral and central taste coding using Drosophila melanogaster
Dissecting Taste Neural circuits and taste modulation:
Taste is extremely important for all the organisms to evaluate and choose foods that are rich in calories and avoid bitter compounds that may be toxic. Using their peripheral taste organs (Labellum, legs, wings and genitalia), flies detect different taste compounds in their environment.Taste information present at the periphery must be processed by the central circuits for the final behavioral output. Identification and understanding of neural circuitry regulating taste behavior is required to understand the neural basis of taste preference. In humans, abnormal nutrient consumption causes metabolic conditions like obesity and diabetes. Despite this burden on society, neuronal circuits that regulate appetite and influence feeding behaviors are undetermined. We are using genetic model system Drosophila that can sense the same taste stimuli as mammals (sugars, sour, water, salt, umami and bitter) to study the molecular and cellular mechanisms by which specific neural circuits underlie modulation of aste function and orchestrate observable
taste driven behaviors (acceptance or rejection).In particular, we are trying to understand (1) novel taste circuits in the brain (2) physiological state and factors that act on the taste cells and circuits (3) modulation of the taste behavior. Identification of unknown central taste circuits will provide valuable insight into the neural architecture of appetitive and aversive circuits.
Understanding the link: Obesity and Satiety
While enjoying food, it is essential that one should know when to stop when you are full. Metabolic conditions and eating disorders including obesity, diabetics, cardiovascular diseases and hypertension are affecting millions of people every year. Increased consumption of sweet products is a growing concern with medical authorities and it has been linked to the rising incidents of Diabetes and Obesity all over the world. Hence, it is essential to balance the nutrient intake and maintain stable body weight to regulate metabolism. The lab is interested in exploring how the hunger and satiety are achieved by identifying pathways, neurons and genes involved in Drosophila and relate our findings to homologous mammalian genes with similar functions to discover conserved pathways that regulate hunger and satiety.
Eat it right :
Salt (NaCl) is an essential component of our diets. Presence of salt makes food more palatable than the same food with no salt. Right and small amounts of salt is essential for our health. Literature suggest that adults need less than 1 gram per day and children need even less. In India, general salt consumption is approximately 8.0 g of salt per day, far more than we need, putting us at risk of various health problems like blood pressure. Raised blood pressure (hypertension) is the major factor which causes strokes, heart failure and heart attacks, the leading causes of death and disability worldwide. There is also increasing evidence of a link between high salt intake and stomach cancer, osteoporosis, obesity, kidney stones, kidney disease and vascular dementia and water retention. Salt can also exacerbate the symptoms of asthma, Ménière’s disease and diabetes. A high salt diet can cause calcium to be lost from bones and excreted in the urine, making bones weak and easily broken.
Various hypothesis suggest that optimal salt preferences are learned. Early experience with low or high salt diets may have a long-term impact on preferred salt levels. Liking for salt, similar to liking for sweets, has an innate basis that can be modified by individual experience.
We are using Drosophila melanogaster to understand the behavioral and sensory factors involved in maintaining high salt preference as a prerequisite to successful programs aimed at reducing intake.
Healthy aging, healthy eating:
Both smell and taste play vital roles in food enjoyment and safety. A delightful meal or pleasant smell can improve social interaction and enjoyment of life. Various groups have reported that number of taste buds decreases with age. Sensitivity to the five main tastes often declines after age 60. In addition, our mouth produces less saliva as we age.
This can cause dry mouth, which can affect your sense of taste. Decreased taste and smell can lead to less interest, diminished appetite and no enjoyment while eating. Using Drosophila, we are trying to understand the effects of aging and diseased condition on taste behavior. Understanding the taste age-related factors can help us prepare to accept change, adapt, and be aware of potential hazards and help in aging gracefully with changed heathy eating habits.
Modulation of taste behavior by phytochemicals in Drosophila melanogaster.
Sugar is a main source of energy for nearly all animals. But consumption of high amount of sugars can lead to many metabolic disorders including obesity, diabetes and cardiovascular diseases, hence balancing calorie intake in the form of sugar is required. Taste helps in evaluating and choose food rich in calories and avoid compounds that are toxic to the body. Various herbs are in use to control the body weight, cure diabetes and control the elevated blood sugar levels. We have identified many phytochemicals to selectively inhibit sugar sensation and curb the cravings for sugar. Using Drosophila, we are trying to understand the effect of these phytochemicals on the feeding behavior of flies. Our preliminary studysuggeststhe potential of some of these phytochemicals to be used in developing cost effective strategies for pest control using raw powered form and save agricultural crops from insects.