Nocturnal animals need their noses to stay alive. Mice, among others, depend on their impressive olfactory powers to sniff out food or avoid danger in the dark.
Juvenile mice secrete a protective pheromone in their tears, blocking adult mating
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Scientists find insect DEET receptors, develop safe alternatives to DEET
Insects are repelled by N,N-diethyl-m-toluamide, also known as DEET. But exactly which olfactory receptors insects use to sense DEET has eluded scientists for long. Now researchers at the University of California, Riverside have identified these DEET-detecting olfactory receptors that cause the repellency—a major breakthrough in the field of olfaction.
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Chemical passwords could lead to unbreakable molecular lock
(Phys.org) —If you're in the business of cracking codes, it would be pretty difficult to break into a security system that you don't even know is there. That's one of the advantages of molecular keypad locks, whose small sizes make them very difficult to detect. As such, these locks are an example of steganography, since not only is the password hidden, but the very existence of the lock itself is concealed. Another advantage of these tiny locks is that, instead of using electronic signals, they use chemical and optical signals that further complicate their cracking.
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Captive breeding for thousands of years has impaired olfactory functions in silkmoths
A new study on silkmoths revealed that the insects' ability to perceive environmental odors has been reduced after about 5,000 years of domestication by humans. Scientists from the Max Planck Institute for Chemical Ecology in Jena, Germany, and their colleagues from Japan compared olfactory functions in Bombyx mori and in their wild ancestors. Perception of the pheromone bombykol, however, remained highly sensitive in domesticated males.
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Mosquito sperm have 'sense of smell'
Vanderbilt biologists have discovered that mosquito sperm have a "sense of smell" and that some of same chemicals that the mosquito can smell cause the sperm to swim harder.
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Scientists find distinctive patterns of olfactory receptors in fruit-eating bats
How do we smell? The answer lies in the 1,000 or so genes that encode what's known as olfactory receptors inside our noses.
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The first insects were not yet able to smell well
An insect's sense of smell is vital to its survival. Only if it can trace even tiny amounts of odor molecules is it is able to find food sources, communicate with conspecifics, or avoid enemies. According to scientists at the Max Planck Institute for Chemical Ecology in Jena, Germany, many proteins involved in the highly sensitive odor perception of insects emerged rather late in the evolutionary process. The very complex olfactory system of modern insects is therefore not an adaptation to a terrestrial environment when ancient insects migrated from water to land, but rather an adaptation that appeared when insects developed the ability to fly. The results were published in the Open Access Journal eLife.
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Combatting malaria using natural mosquito repellents
Repellents derived from Greek herb extracts show potent effects, as spatial repellents, against malaria carrying mosquitoes, and possibly others.
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Odor code for food is based on a few volatile substances
(Phys.org) —The actual flavor of a food is experienced through our sense of smell rather than with our tongue. However, of the large number of volatile compounds in foods, only about 230 are involved in the scent, as reported by German scientists in the journal Angewandte Chemie. The different smells derive from characteristic combinations of three to forty of these odorants.
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Elephants possess 'superior' sense of smell, study finds
Elephants possess a sense of smell that is likely the strongest ever identified in a single species, according to a study by Japanese scientists out Tuesday.
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Odor molecules monitor pest that spreads devastating citrus disease
The Asian citrus psyllid (ACP) is an efficient vector of a bacterium that causes a lethal citrus disease, huanglongbing (HLB), one of the most destructive diseases of citrus worldwide.
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Nasal immunity is an ancient adaptation of the mucosal immune system of vertebrates
(Phys.org) —Researchers at the University of New Mexico recently discovered an olfactory immune system in fish previously thought to be associated with terrestrial vertebrates only. The results could provide a new tool for the control of infectious diseases in fish farms and hatcheries.
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How does a machine smell? Better than it did
Every odor has its own specific pattern which our noses are able to identify. Using a combination of proteins coupled to transistors, for the first time machines are able to differentiate smells that are mirror images of each other, so called chiral molecules, something that has not been possible before. The human nose can distinguish between some of these molecules and the different forms of the same molecule of carvone, for example, can smell either like spearmint or caraway. Previous machines would not have been able to distinguish between the two.
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Design and enantioselective synthesis of new Cashmeran odorants
When a perfume is said to include Cashmere Wood, it means the typical smell of the odorant Cashmeran. As described in the journal Angewandte Chemie, scientists from Switzerland and Germany have introduced new members in this exclusive and precious family of scents, by using a novel synthetic strategy to synthesize enantiomerically pure products. Olfactory analysis of these compounds provided insight into the structural requirements for Cashmeran odorants.
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Fruit flies use olfactory cues to detect healthy antioxidants in their food
Antioxidants are natural food ingredients that protect cells from harmful influences. Their main task is to neutralize so-called "free radicals" which are produced in the process of oxidation and which are responsible for cell degeneration. Scientists at the Max Planck Institute for Chemical Ecology in Jena, Germany, and the University of Lund, Sweden, now show that vinegar flies are able to detect these protective substances by using olfactory cues. Odors that are exclusively derived from antioxidants attract flies, increase feeding behavior and trigger oviposition in female flies.
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Picking up on the smell of evolution
UA researchers have discovered some of the changes in genes, physiology and behavior that enable a species to drastically change its lifestyle in the course of evolution.
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Leaf odor attracts Drosophila suzukii
In 2014, more spotted-wing Drosophila suzukii than ever before were observed in Germany. This pest lays its eggs in fresh and ripening fruits before they are harvested. Infested fruits are often additionally infected with bacteria and fungi, and become unsuitable for sale and further processing. Currently, the only way to effectively control this pest insect is through the use of insecticides. Scientists at the Max Planck Institute for Chemical Ecology have now identified a leaf odor which is highly attractive to Drosophila suzukii. Beta-cyclocitral lures the spotted-wing drosophila but no other related drosophilids. Researchers were able to measure the olfactory specialization of the insect to this leaf odor on the basis of the response of a certain sensillum.
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Plausibility of the vibrational theory of smell
The vibrational theory of olfaction explains several aspects of odorant detection that theories based purely on receptor binding do not. It provides for additional selectivity through receptors that are tuned to specific vibrational bands of the odorants they bind, and also through the subsequent conduction of electrons across the odorant, presumably by a tunneling mechanism. A lot of people seem like the theory, or at least its main theorist, Luca Turin. Over the years, efforts to prove, or disprove the vibrational theory have progressed through a long series of olfactory touchstones: molecular enigmas like carvone, acetophenone, or benzaldehyde, whose experimentally perceived scent is a seemingly fickle amalgam of various molecular vibrations, mirror images, and isotopes.
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One simple molecule regulates sexual behavior in Drosophila
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.
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Cracking the function of the fly olfactory system to understand how neural circuits work
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.
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