The first insects were not yet able to smell well: Odorant receptors evolved long after insects migrated from water to land

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, 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.Many insect species employ three families of receptor proteins in order to perceive thousands of different environmental odors. Among them are the olfactory receptors. They form a functional complex with another protein, the so-called olfactory receptor co-receptor, which enables insects to smell the tiniest amounts of odor molecules in their environment very rapidly.Crustaceans and insects share a common ancestor. Since crustaceans do not have olfactory receptors, previously scientists assumed that these receptors evolved as an adaptation of prehistoric insects to a terrestrial life. This hypothesis is also based on the assumption that for the ancestors of recent insects, the ability to detect odor molecules in the air rather than dissolved in water was of vital importance.Early research on insect olfactory receptors focused entirely on insects with wings. Ewald Groe-Wilde and Bill S. …

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Massive neutrinos solve a cosmological conundrum

Scientists have solved a major problem with the current standard model of cosmology identified by combining results from the Planck spacecraft and measurements of gravitational lensing in order to deduce the mass of ghostly sub-atomic particles called neutrinos.The team, from the universities of Manchester and Nottingham, used observations of the Big Bang and the curvature of space-time to accurately measure the mass of these elementary particles for the first time.The recent Planck spacecraft observations of the Cosmic Microwave Background (CMB) — the fading glow of the Big Bang — highlighted a discrepancy between these cosmological results and the predictions from other types of observations.The CMB is the oldest light in the Universe, and its study has allowed scientists to accurately measure cosmological parameters, such as the amount of matter in the Universe and its age. But an inconsistency arises when large-scale structures of the Universe, such as the distribution of galaxies, are observed.Professor Richard Battye, from The University of Manchester School of Physics and Astronomy, said: “We observe fewer galaxy clusters than we would expect from the Planck results and there is a weaker signal from gravitational lensing of galaxies than the CMB would suggest.”A possible way of resolving this discrepancy is for neutrinos to have mass. The effect of these massive neutrinos would be to suppress the growth of dense structures that lead to the formation of clusters of galaxies.”Neutrinos interact very weakly with matter and so are extremely hard to study. They were originally thought to be massless but particle physics experiments have shown that neutrinos do indeed have mass and that there are several types, known as flavours by particle physicists. The sum of the masses of these different types has previously been suggested to lie above 0.06 eV (much less than a billionth of the mass of a proton).In this paper, Professor Battye and co-author Dr Adam Moss, from the University of Nottingham, have combined the data from Planck with gravitational lensing observations in which images of galaxies are warped by the curvature of space-time. They conclude that the current discrepancies can be resolved if massive neutrinos are included in the standard cosmological model. They estimate that the sum of masses of neutrinos is 0.320 +/- 0.081 eV (assuming active neutrinos with three flavours).Dr Moss said: “If this result is borne out by further analysis, it not only adds significantly to our understanding of the sub-atomic world studied by particle physicists, but it would also be an important extension to the standard model of cosmology which has been developed over the last decade.”The paper is published in Physical Review Letters and has been selected as an Editor’s choice.Story Source:The above story is based on materials provided by University of Manchester. Note: Materials may be edited for content and length.

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I’m OK, you’re not OK: Right supramarginal gyrus plays an important role in empathy

Oct. 9, 2013 — Egoism and narcissism appear to be on the rise in our society, while empathy is on the decline. And yet, the ability to put ourselves in other people’s shoes is extremely important for our coexistence. A research team headed by Tania Singer from the Max Planck Institute for Human Cognitive and Brain Sciences has discovered that our own feelings can distort our capacity for empathy. This emotionally driven egocentricity is recognised and corrected by the brain. When, however, the right supramarginal gyrus doesn’t function properly or when we have to make particularly quick decisions, our empathy is severely limited.When assessing the world around us and our fellow humans, we use ourselves as a yardstick and tend to project our own emotional state onto others. While cognition research has already studied this phenomenon in detail, nothing is known about how it works on an emotional level. It was assumed that our own emotional state can distort our understanding of other people’s emotions, in particular if these are completely different to our own. But this emotional egocentricity had not been measured before now.This is precisely what the Max Planck researchers have accomplished in a complex marathon of experiments and tests. They also discovered the area of the brain responsible for this function, which helps us to distinguish our own emotional state from that of other people. …

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Older adults gauge their partner’s feelings through knowing, not seeing

Sep. 10, 2013 — Compared to younger adults, older people are less adept at reading emotion in their spouse’s face. But when their spouse isn’t present, older and younger adults are equally able to discern their significant others’ moods.These findings, published in Psychological Science, a journal of the Association for Psychological Science, suggest that older adults retain the ability to make accurate judgments about others’ emotions using their acquired knowledge, but not sensory cues.”When judging others’ emotions in real life, people do not exclusively rely on emotional expressions,” says lead researcher Antje Rauers of the Max Planck Institute for Human Development in Germany. “Instead, they use additional information, such as accumulated knowledge about a given situation and a particular person.”To investigate how these two processes vary with age, Rauers and colleagues Elisabeth Blanke and Michaela Riediger recruited 100 couples, some of whom were between the ages of 20 and 30 and some of whom were between the ages of 69 and 80. When they came to the lab, Rauer and colleagues first showed various faces to the participants, asking them to identify particular emotions.”We started by replicating past research, showing that older adults are typically worse than younger adults at interpreting emotions through facial expressions,” Rauers explains.Then the researchers took the study outside the lab, asking participants to record their own emotions and the emotions of their partners six times a day for two weeks using a cell phone.When the participant’s partner was nearby, the participant could use his or her partner’s facial expressions as an indicator of their emotions. But it was those moments when the partner was absent, which occur frequently in everyday life, that the researchers were particularly interested in.Even though partners were sometimes in different places, they recorded their emotions at the exact same times throughout the day. This way, the researchers could tell if one partner was accurately estimating how the other partner felt at that particular moment.The data revealed that older adults were not as adept as younger adults at reading the expressions in their partner’s face — when both partners were present, the older adults estimated consistently worse than their younger counterparts. These findings confirmed the results from the expression recognition task completed in the lab.But the age differences disappeared when the researchers looked at only those moments when the partners were separated. In these cases, both older adults and younger adults were equally good at estimating how their partner was feeling at a given moment.These findings suggest that some cognitive processes associated with understanding and empathizing with one’s partner remain stable as we age.”Reading emotional expressions may become more difficult with age, but using one’s knowledge about a familiar person remains a reliable strategy throughout adulthood,” Rauers concludes.”This is really good news, given that the overwhelming majority of research findings testifies an age-related decline in many competencies,” says Rauers. “Our data suggest that knowing your loved ones well is an important resource that stays available throughout life.”

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Hubble bubble may explain different measurements of expansion rate of the universe

Sep. 9, 2013 — The existence of the “Hubble Bubble” may explain, at least in part, the differing measurements for the expansion and therefore the age of the universe. That is the assumption of a team of physicists headed by Prof. Dr. Luca Amendola from the Institute for Theoretical Physics at Heidelberg University. In collaboration with colleagues from the Netherlands, the Heidelberg physicists developed a theoretical model that places the Milky Way inside of this type of cosmic bubble. The researchers believe the bubble can explain some of the deviations between previous measurements and the latest ones from the Planck satellite of the European Space Agency (ESA).The results of their research were published in the journal Physical Review Letters.The observable universe has been expanding since the Big Bang. It still is, causing galaxies in our Milky Way to recede. The actual speed of this expansion is known as the Hubble constant. Due to its importance in calculating basic properties of the universe, such as its age, modern cosmology is tasked with determining the value of the constant. …

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A magnetar at the heart of our Milky Way

Aug. 14, 2013 — Astronomers have discovered a magnetar at the centre of our Milky Way. This pulsar has an extremely strong magnetic field and enables researchers to investigate the direct vicinity of the black hole at the heart of the galaxy. An international team of scientists headed by the Max Planck Institute for Radio Astronomy in Bonn have, for the first time, measured the strength of the magnetic field around this central source and were able to show that the latter is fed by magnetic fields. These control the inflow of mass into the black hole, also explaining the x-ray emissions of this gravity trap.The discovery of a pulsar closely orbiting the candidate supermassive black hole at the centre of the Milky Way (called Sagittarius A*, or Sgr A* in short) has been one of the main aims of pulsar astronomers for the last 20 years. Pulsars, those extremely precise cosmic clocks, could be used to measure the properties of space and time around this object, and to see if Einstein’s theory of General Relativity could hold up to the strictest tests.Shortly after the announcement of a flaring X-ray source in the direction of the Galactic centre by NASA’s Swift telescope, and the subsequent discovery of pulsations with a period of 3.76 seconds by NASA’s NuSTAR telescope, a radio follow-up program was started at the Effelsberg radio observatory of the Max Planck Institute for Radio Astronomy (MPIfR).”As soon as we heard about the discovery of regular pulsations with the NuSTAR telescope we pointed the Effelsberg 100-m dish in the direction of the Galactic centre,” says Ralph Eatough from MPIfR’s Fundamental Physics Research department, the lead author of the study. “On our first attempt the pulsar was not clearly visible, but some pulsars are stubborn and require a few observations to be detected. The second time we looked, the pulsar had become very active in the radio band and was very bright. I could hardly believe that we had finally detected a pulsar in the Galactic centre!” Because this pulsar is so special, the research team spent a lot of effort to prove that it was a real object in deep space and not due to human-made radio interference created on Earth.Additional observations were performed in parallel and subsequently with other radio telescopes around the world (Jodrell Bank, Very Large Array, Nançay). “We were too excited to sleep in between observations! …

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Motional layers found in the brain: Neurobiologists discover elementary motion detectors in the fruit fly

Aug. 7, 2013 — Recognising movement and its direction is one of the first and most important processing steps in any visual system. By this way, nearby predators or prey can be detected and even one’s own movements are controlled. More than fifty years ago, a mathematical model predicted how elementary motion detectors must be structured in the brain. However, which nerve cells perform this job and how they are actually connected remained a mystery. Scientists at the Max Planck Institute of Neurobiology in Martinsried have now come one crucial step closer to this “holy grail of motion vision”: They identified the cells that represent these so-called “elementary motion detectors” in the fruit fly brain. The results show that motion of an observed object is processed in two separate pathways. In each pathway, motion information is processed independently of one another and sorted according to its direction.Ramón y Cajal, the famous neuroanatomist, was the first to examine the brains of flies. Almost a century ago, he thus discovered a group of cells he described as “curious elements with two tufts.” About 50 years later, German physicist Werner Reichardt postulated from his behavioural experiments with flies that they possess “elementary motion detectors,” as he referred to them. These detectors compare changes in luminance between two neighbouring photoreceptor units, or facets, in the fruit fly’s eye for every point in the visual space. …

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Making connections in the eye: Wiring diagram of retinal neurons is first step toward mapping the human brain

Aug. 7, 2013 — The human brain has 100 billion neurons, connected to each other in networks that allow us to interpret the world around us, plan for the future, and control our actions and movements. MIT neuroscientist Sebastian Seung wants to map those networks, creating a wiring diagram of the brain that could help scientists learn how we each become our unique selves.In a paper appearing in the Aug. 7 online edition of Nature, Seung and collaborators at MIT and the Max Planck Institute for Medical Research in Germany have reported their first step toward this goal: Using a combination of human and artificial intelligence, they have mapped all the wiring among 950 neurons within a tiny patch of the mouse retina.Composed of neurons that process visual information, the retina is technically part of the brain and is a more approachable starting point, Seung says. By mapping all of the neurons in this 117-micrometer-by-80-micrometer patch of tissue, the researchers were able to classify most of the neurons they found, based on their patterns of wiring. They also identified a new type of retinal cell that had not been seen before.”It’s the complete reconstruction of all the neurons inside this patch. No one’s ever done that before in the mammalian nervous system,” says Seung, a professor of computational neuroscience at MIT.Other MIT authors of the paper are former postdoc Srinivas Turaga and former graduate student Viren Jain. The Max Planck team was led by Winfried Denk, a physicist and the Max Planck Institute’s director. Moritz Helmstaedter, a research group leader at the Max Planck Institute, is the lead author of the paper, and Kevin Briggman, a former postdoc at Max Planck, is also an author.Tracing connectionsNeurons in the retina are classified into five classes: photoreceptors, horizontal cells, bipolar cells, amacrine cells and ganglion cells. Within each class are many types, classified by shape and by the connections they make with other neurons.”Neurons come in many types, and the retina is estimated to contain 50 to 100 types, but they’ve never been exhaustively characterized. …

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Hormone receptors may regulate effect of nutrition on life expectancy not only in roundworms, but perhaps also in humans

Aug. 6, 2013 — A reduced caloric intake increases life expectancy in many species. But how diet prolongs the lives of model organisms such as fruit flies and roundworms has remained a mystery until recently. Scientists at the Max Planck Institute for Biology of Ageing in Cologne discovered that a hormone receptor is one of the links between nutrition and life expectancy in the roundworms.The receptor protein NHR-62 increases the lifespan of the animals by twenty per cent if their calorie intake is reduced. Furthermore, another study showed that the hormone receptor NHR-8 affects development into adulthood as well as the maximum lifespan of the worms. It may be possible that receptors related to these are also responsible for regulating life expectancy in human beings.The roundworm Caenorhabditis elegans lives only about 20 days. This makes it an ideal research subject, as the complete lifecycle of the worm can be studied in a short time. Also, the worm consists of less than a thousand cells, and its genetic make-up has been extensively analysed, and contains many genes similar to humans. The scientists in Adam Antebi’s team at the Max Planck Institute for Biology of Ageing use Caenorhabditis elegans to find out how hormones influence ageing. They are particularly interested in hormone receptors that reside in the cell nucleus, which regulate the activity of metabolic genes.Their results indicate that the receptor NHR-62 must be active for reduced dietary intake to fully prolong the life of worms. …

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Depressed fish could help in the search for new drug treatments

Aug. 5, 2013 — Antidepressant normalises the behaviour of zebrafish with a defective stress hormone receptor.Chronic stress can lead to depression and anxiety in humans. Scientists working with Herwig Baier, Director at the Max Planck Institute of Neurobiology in Martinsried, recently discovered a very similar link in fish. Normally, the stress hormone cortisol helps fish, as in humans, to regulate stress. Fish that lack the receptor for cortisol as a result of a genetic mutation exhibited a consistently high level of stress. They were unable to adapt to a new and unfamiliar situation. The fishes’ behaviour returned to normal when an antidepressant was added to the water. These findings demonstrate a direct causal link between chronic stress and behavioural changes which resemble depression. The findings could also open the door to an effective search for new drugs to treat psychiatric disorders.In stressful situations, the body releases hormones in order to ready itself for a fight or flight reaction. But it is equally important for the hormone level to return to normal after a certain time. …

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The power of imitation: Already in infancy, imitation promotes a general pro-social orientation toward others

June 27, 2013 — Being mimicked increases pro-social behaviour in adults, yet little is known about its social effect on children. Researchers of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, have now investigated whether the fact of being imitated had an influence on infants’ pro-social behaviour and on young children’s trust in another person.In one study, eighteen-month-old infants were either mimicked or not by an experimenter. Later, when this experimenter or a different adult needed help, infants who had been imitated were more likely to help spontaneously. In a second study, five- to six-year-olds interacted with one experimenter who mimicked their choices and another experimenter who made independent choices. The researchers found that the children were more likely to trust the preferences and factual claims of the experimenter who had mimicked them before. These results demonstrate that already in infancy mimicry promotes a general pro-social orientation toward others and that in young children imitation is a powerful means of social influence in development.Imitation is not only a means by which we learn from others. As adults, we routinely and automatically copy each other’s movements, postures, and facial expressions, and this has a variety of positive social consequences. After being mimicked, we behave more helpfully and generously toward others, from picking up others’ dropped belongings to giving more money to charity. Much less is known, however, about the social effects of imitation on infants and young children.Focusing on the social side of imitation, the researchers tested in a first study whether being mimicked increased pro-social behaviour in infants, as it does in adults. To this end, 48 eighteen-month-old infants were either mimicked or not by an experimenter: In the mimic condition, the experimenter immediately copied everything she saw or heard infants do. …

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City slicker or country bumpkin: City-life changes blackbird personalities

June 19, 2013 — The origins of a young animal might have a significant impact on its behaviour later on in life. Researchers at the Max Planck Institute for Ornithology in Radolfzell, Germany, have been able to demonstrate in hand-reared blackbirds that urban-born individuals are less curious and more cautious about new objects than their country counterparts. This study sheds light on an interesting debate on whether personality differences between rural and urban birds are behavioural adjustments to urban environments, or if there is an underlying evolutionary basis to the existence of different personalities in urban habitats.It’s something pet owners have always known: animals have personalities too. More than 100 species have so far been identified by scientists where individuals consistently follow distinct behavioural strategies and behave in similar ways in a variety of situations. Scientists believe that such differences may also be important in adapting to new habitats.Urbanization has considerably changed the living conditions of many wild animals. Animals living in urban areas need to cope with new anthropogenically-altered living conditions. A textbook example is the European blackbird (Turdus merula). Historically a forest-dweller, the blackbird is now one of the most common bird species found in our cities. In these new habitats, the blackbird has changed its behaviour in many ways: urban blackbirds migrate less in the winter, breed earlier, and live in higher densities than their forest conspecifics.Cities might be also responsible for fundamental changes in the behaviour of wild animals across the globe. A team from the Max Planck Institute for Ornithology in Radolfzell analysed existing studies on differences between urban and rural populations of various species. …

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Flowering at the right age: Alpine rock cress uses a ribonucleic acid to measure its age and tell when it’s the right time to flower

June 10, 2013 — Perennial plants flower only when they have reached a certain age and been subjected to the cold. These two circumstances prevent the plant from starting to flower during winter. George Coupland and his fellow scientists from the Max Planck Institute for Plant Breeding Research in Cologne have now discovered that the Alpine rock cress determines its age based on the quantity of a short ribonucleic acid.Perennial plants carefully balance periods of growth and flowering to ensure that they can live for many years. They do not flower when they are still too young and small or produce flowers on all their side shoots. Also, they do not flower out of season and they continue to grow after flowering. In temperate regions they do not produce flowers during winter but only after exposure to a long cold period. This dependency on a cold stimulus is called vernalisation. George Coupland, Sara Bergonzi, Maria Albani and other scientists from the Max Planck Institute for Plant Breeding Research have now identified the molecular signals used by the perennial Alpine rock cress (Arabis alpina) to register its ageand to realise that it has been exposed to vernalisation. Only when the right age has been reached and the chill has had its effect can flowers begin to form.The Alpine rock cress measures its age based on the concentration of a short ribonucleic acid known as miR156. A purely regulatory nucleic acid, miR156 works like an hourglass. …

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Female moths use olfactory signals to choose the best egg-laying sites

June 3, 2013 — Functional calcium imaging in the antennal lobes of a female Manduca sexta moth: Different activation patterns (red spots) can be observed depending on whether the moths respond to (Z)-3-hexenyl acetate or (E)-2-hexenyl acetate. The odor of a (Z)-3-isomer or a (Z)-3 / (E)-2 ratio in favor of a (Z)-3-isomer − according to the odor bouquet of an unattacked plant − guides ovipositing Manduca females to plants that have yet been spared by herbivorous caterpillars. Copyright: Anna Späthe, MPI Chem. Ecol.Researchers at the Max Planck Institute for Chemical Ecology, Jena, Germany, discovered that the ability of Manduca sexta moths to recognize changes in the profile of volatile compounds released by plants being attacked by Manduca caterpillars allows them to lay their eggs on plants that are less likely to be attacked by insects and other predators, and to avoid competing against other caterpillars of the same species for resources. The results of field experiments and neurobiological studies were now published in the open access online journal eLIFE. (eLIFE, May 14, 2013, DOI: 10.7554/elife.00421)”Green” leaf odorsPlants have developed many different strategies to defend themselves against herbivorous animals, particularly insects. In addition to mechanical defenses such as thorns and spines, plants also produce compounds that keep insects and other herbivores at bay by acting as repellents or toxins. Some of these metabolites are produced on a continuous basis by plants, whereas others — notably compounds called green-leaf volatiles — are mainly produced once the plant has been wounded or attacked. Green-leaf volatiles — which are also responsible for the smell of freshly cut grass — have been observed to provide plants with both direct protection, by inhibiting or repelling herbivores, and indirect protection, by attracting predators of the herbivores themselves.Attracting the enemies of the herbivoresThe hawkmoth Manduca sexta lays its eggs on various plants, including tobacco and Sacred Datura plants (Datura wrightii). Once the eggs have hatched into caterpillars, they start eating the leaves of their host plant, and if present in large numbers, these caterpillars can quickly defoliate and destroy the plant. …

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