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Channel: Phys.org news tagged with:olfactory

One simple molecule regulates sexual behavior in Drosophila

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The common vinegar fly Drosophila melanogaster is a very well-studied animal. For decades, the fly has been used as a model organism in genetic research; its genome was fully sequenced in 2000. However, until now researchers have failed to identify the specific pheromone in this species that leads to mating success. Although the pheromones that inhibit mating in Drosophila were known, the positive pheromone signal that elicits courtship behavior and mating remained a mystery. Scientists from the Max Planck Institute for Chemical Ecology in Jena, Germany, have succeeded in identifying a relatively simple molecule that is able to regulate complex mating behavior in vinegar flies: a fatty acid methyl ester called methyl laurate. Verification was a result of the combination of state-of-the-art chemical analytic techniques, physiological measurements in the fly brain, and behavioral assays.

Cracking the function of the fly olfactory system to understand how neural circuits work

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If a banana is rotting in the fruit basket of your kitchen, chances are that a fruit fly will find it long before you do. How is the nervous system of a tiny fly capable of ascending the odour trail created by a banana? This question has been addressed in a new study conducted by the Sensory Systems and Behaviour laboratory led by Matthieu Louis at the EMBL-CRG Systems Biology Unit of the CRG. The fruit fly Drosophila melanogaster is an excellent model system to explore how complex behaviours, such as chemotaxis, are controlled by the activity of neural circuits. Although the word neuroscience may evoke the human brain to most of us, research in smaller genetic model organisms often represents the most direct entry point into the molecular and cellular basis neural functions.

A controversial theory of olfaction deemed implausible

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Humans can discriminate tens of thousands of odors. While we may take our sense of smell for granted, it adds immeasurably to our quality of life: the aroma of freshly brewed coffee; the invigorating smell of an ocean breeze or a field of wildflowers; the fragrance of a lover or the natural smell of a baby. Our olfactory sense also warns us when milk turns rancid, when a baby's diaper needs changing and when there's a gas leak. In animals, the sense of smell is essential for detection of predators and other dangers, food sources and mates.

Making sense of our evolution

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The science about our our special senses - vision, smell, hearing and taste - offers fascinating and unique perspectives on our evolution.

Study of birds' sense of smell reveals important clues for behavior and adaptation

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From slight sparrows to preening peacocks to soaring falcons, birds have long been known to possess distinct abilities in their sense of smell, but little has been known about the evolution of olfaction.

How do ants identify different members of their society?

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Ants, which are eusocial insects, have intrigued scientists for long as a model for cooperation inside a colony where they nurse the young, gather food and defend against intruders. Most recently, ants have been shown to cooperate when transporting big chunks of food, they have been studied for how they manage to keep clean, and they have been examined also for why most of them in a colony are lazy. Add to this list now how ants identify different members of their colony from other colonies.

Better learning through neural distinguishing

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A study published in the latest issue of Nature Neuroscience describes work led by the University of Geneva's (UNIGE) Faculties of Medicine and Sciences, on the indisputable role of the olfactory bulb in mammal brains' ability to discriminate between smells. This research has verified the importance of a very active neural network, which cuts, prunes, and models the sequence of electrical impulses that result from information transmitted by the nose. Although the interpretation needed to distinguish between different smells takes place in the cortex, this step is greatly facilitated by the work done by the bulb neurons who put together the information to be read. From a behavioral perspective this concerns the learning process since the brain is better at learning and recalling what it can clearly differentiate.

For worms, positive thinking is the key to finding food

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Caenorhabditis elegans, a tiny roundworm, spends much of its lifetime searching for soil bacteria to eat. This humble creature possesses 302 neurons, which may not seem like a lot compared to the billions of nerve cells that make up the human brain. Nonetheless, it uses sophisticated strategies to reach nutritionally promising places.

Same switches program taste and smell in fruit flies

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A new study sheds light on how fruit flies get their keen sense of smell.

New evidence for the vibration theory of smell

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(Phys.org)—The predictive power and galvanizing influence that theoretical models routinely enjoy in physics is only rarely replicated in biology. Lord Raleigh's theory of sound perception, Francis Crick's sequence and adapter hypotheses, and Hodgkin and Huxley's model of the electrical dynamics of neurons are a few notable exceptions that have gone on to spawn entire scientific industries. Although it is hard to find comparable mechanistic drama unfolding in our current century, Luca Turin's vibrational theory of olfaction has been a persistently fertile seed that has now ripened into a contentious fruit.

Mechanism discovered for mosaic pattern of cells in the nasal cavity

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Every cell in our bodies has its proper place, but how do they get there? A research group led by Kobe University Graduate School of Medicine Ph.D. student KATSUNUMA Sayaka and Assistant Professor TOGASHI Hideru discovered the mechanism for a mosaic pattern formation of two different cell types. Their discovery has potentially broad applications as a common principle for determining pattern formation in different types of cell. The findings were published in the Journal of Cell Biology on February 29, 2016.

Study yields insight into the mystery of smell

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Researchers at the University of Pittsburgh School of Medicine have uncovered the mechanism underlying a phenomenon in how we smell that has puzzled researchers for decades. In an article appearing online today in the Proceedings of the National Academy of Sciences, the team reports that, surprisingly, the mechanism follows a simple physics principle called cooperativity.

Olfactory receptor discovered in pigment cells of the skin

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Researchers at Ruhr-Universität Bochum were the first ones to prove the existence of an olfactory receptor in pigment-producing cells in human skin, the so-called melanocytes. The team headed by Prof Dr Dr Dr habil. Hanns Hatt demonstrated that the violet-like scent Beta-Ionone can activate the receptor.

Using the 'deuterium switch' to understand how receptors work

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(Phys.org)—The market value for deuterated drugs has recently been estimated at over a billion dollars. Such drugs are simply molecules in which one or more hydrogen atoms are replaced with deuterium. While these kinds of manipulations are known to work wonders as far as breathing new life into aging patents, the overall therapeutic value of this medical manna can be contentious. A recent paper published in PLoS ONE seeks to explain the 'quantum nature of drug-receptor interactions' under deuteration using a combined experimental and computational approach. Although a tall order, a more comprehensive and predictive theory of receptor interactions is sorely needed. Perhaps a theory in which the molecular character of drug effects are written less into the receptor and more into the drug itself.

The basic units of the olfactory system in the fly brain provide references to their function and ecological relevance

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Scientists at the Max Planck Institute for Chemical Ecology in Jena, Germany, have now quantified and mapped the functional units of the olfactory center in the brains of vinegar flies responsible for the perception of odors. They found out that the so-called olfactory glomeruli in the antennal lobe, the insect analogue of the olfactory bulb of mammals, differ from each other in their architecture. The morphology and the structure of these spherical brain units provide information about the ecological relevance of the odors they process, especially with regard to the flies' odor-guided behavior.

Understanding sulfur's rotten smell

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Though odorless in its normal state, utility companies add sulfur-containing odorants - called mercaptans or thiols - to the gas so it's easy to detect a leak. The foul smell is reminiscent of rotting cabbage or spoiled eggs.

3-D imaging technique maps migration of DNA-carrying material at the center of cells

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Scientists have mapped the reorganization of genetic material that takes place when a stem cell matures into a nerve cell. Detailed 3-D visualizations show an unexpected connectivity in the genetic material in a cell's nucleus, and provide a new understanding of a cell's evolving architecture.

Mice can smell oxygen

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The genome of mice harbours more than 1000 odorant receptor genes, which enable them to smell myriad odours in their surroundings. Researchers at the Max Planck Research Unit for Neurogenetics in Frankfurt, the University of Saarland in Homburg, the University of Cambridge and the Karolinska Institute in Stockholm have discovered that mice can also sense the oxygen level of the inhaled air using neurons in their nose. For this newly discovered sensory property, mice rely on two genes termed Gucy1b2 and Trpc2, but apparently not on odorant receptor genes.

"Ladies choice" reigns in the greater sac-winged bat

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Females of the greater sac-winged bat select their mating partner by smell and unerringly choose a male which differs from them the most in genetic terms. Females with more variants of olfactory receptors of the TAAR-group have an advantage over other females. The results of this study have been released by the Nature Publishing Group in their open access journal Scientific Reports.

The apple maggot fly—how an altered sense of smell could drive the formation of new species

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"Two months ago, we were congratulating ourselves on a fair crop of winterapples. To all appearance, they were freer from worms than we had known them in this section for years. But, alas! our hopes are again blasted. The apple-maggot seems to be as prolific as ever. Two weeks ago, we overhauled two hundred and fifty bushels of apples that we had gathered and placed in store for winter use; and of that number we threw out fifty bushels, most of which had been rendered worthless; and still the work of destruction goes on. The depredations of the apple-maggot continue, converting the pulp of the apple into a mere honeycomb, and rendering another overhauling soon indispensable."

A simple sniff: Nanoparticle research tested in locusts focuses on new drug-delivery method

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Delivering life-saving drugs directly to the brain in a safe and effective way is a challenge for medical providers. One key reason: the blood-brain barrier, which protects the brain from tissue-specific drug delivery. Methods such as an injection or a pill aren't as precise or immediate as doctors might prefer, and ensuring delivery right to the brain often requires invasive, risky techniques.

Genetics and environment combine to give everyone a unique sense of smell

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Researchers from the Wellcome Trust Sanger Institute and their collaborators have shown that receptors in the noses of mice exposed to certain smells during life are different to genetically similar mice that lived without those smells. Published today in eLife, the study found it is this combination of genetics and experience that gives each individual a unique sense of smell.

This nasal receptor mediates the appetizing smell of fish food

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The aquatic environment is full of tantalizing chemicals that can guide a fish to mates or meals. Now, scientists in Japan have identified the olfactory receptor and brain circuitry that picks up the scent of adenosine triphosphate, or ATP. Although mostly known for carrying energy within cells, ATP is also a constituent of fish prey such as brine shrimp and plankton. The newly identified receptor is unique to fish and amphibians and is the gateway to initiating foraging behaviors in the zebrafish.

Using single-cell RNA sequencing and clever statistical analysis to track stem cells as they mature

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Adult stem cells have the ability to transform into many types of cells, but tracing the path individual stem cells follow as they mature and identifying the molecules that trigger these fateful decisions are difficult in a living animal.

It's a myth that humans' sense of smell is inferior to that of other animals – here's why

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Conventional wisdom has it that humans have a poorer sense of smell than most other animals. Sure, we can smell – most of us appreciate the aroma of our morning coffee or a delightful fragrance, and we're able to detect burning toast or a gas leak. But we have nonetheless long been thought to be relative weaklings in the animal kingdom's league of olfactory excellence, which puts dogs and rodents near the top.

Why a crackly crust is essential to a baguette's aroma and taste

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An authentic French baguette is one of those key staples that foodies hunt for. Now scientists have gained new insight into why a crisp crust is a must for this quintessential bread. They report their findings on how crumb and crust structure affect aroma—and therefore, perceived taste—in ACS' Journal of Agricultural and Food Chemistry.

Viral vectors travel longer distances than previously thought

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Gene transfer is seen as a hopeful therapy for Alzheimer's and Parkinson's patients. The approach involves using harmless laboratory-produced viruses to introduce important genes into the brain cells. In a study on mice, a team of researchers from Vetmeduni Vienna for the first time investigated how far these viruses spread in the brain and which cells they infect. Some of the artificial viruses travelled from the injection site in the brain as far as the olfactory bulb or the cerebellum and infected not only neurons but also other cells. The results, which were published in the journal Histochemistry and Cell Biology, could help to improve the selection of suitable viral "gene transporters" for custom therapies using gene transfer.

Researchers demonstrate how some genes evolved from an immune function to an olfactory role in some mammals

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Mammals possess several lines of defense against microbes. One of them is activated when receptors called Fprs, which are present on immune cells, bind to specific molecules that are linked to pathogens. Researchers at the University of Geneva (UNIGE), Switzerland, showed in 2009 that these same receptors were also present in the nose of mice, probably to detect contaminated food or to avoid sick conspecifics. The biologists now describe in the journal PNAS how Fprs have acquired this olfactory role during rodent evolution, moving from the immune system to a neuronal system. This innovation results from two genomic 'accidents' that occurred several millions years apart during the evolution of rodents.

Researchers have identified olfactory receptors that enable ants to smell and recognize workers, males, and their queen

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Queen ants spend most of their time having babies. To reign supreme in a colony, they exude a special scent, or pheromone, on the waxy surface of their body that suppresses ovary development in their sisters, rendering the latter reproductively inactive workers that find food, nurse the young and protect the colony.

Researchers look to the fruit fly to understand the human brain

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The human nervous system is like a complex circuit board. When wires cross or circuits malfunction, conditions such as schizophrenia or bipolar disorder can arise.




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