Author Archives: Elena Motivans

About Elena Motivans

I've always liked the way that words can sound together. Combined with my love for nature (and biology background), I'm interested in diving deep into different topics- in the natural world even the most mundane is fascinating!

A new look at an old fossil reveals how lemurs could have evolved

Lemurs are only found on the island of Madagascar, but no one knows why that is or how they got there. A “bat”, some fossils, and a strange-looking, large-eyed creature have given us some clues. Researchers examined a fossil that had been neglected for about 50 years and found that it held some important information about the origin of lemurs.

Three fossils of three partial mandibles were found in 1967 in Kenya that dated back to the early Miocene period (23 to 16 million years ago). The creature was named Propotto leakeyi and was first thought to be a new species of a loris — a nocturnal primate with large eyes — by paleontologist George Gaylord Simpson. However, his colleague, Alan Walker, convinced him that it was a fruit bat, so a bat it was declared. To be fair, their only clues were inch-long lower jaw bones and tiny teeth. Since that declaration, the identity of P. leakeyi has not been questioned.

A microCT scan of P. leakeyi’s jaw. Image credit: Duke SMIF.

Half a century later, the late paleontologist Gregg Gunnell of Duke University was reexamining the fossils when something struck his eye. There was the stump of a broken front tooth that would have stuck out like a dagger, along with primate-like hind teeth. These combined traits are only known in one other animal: the aye-aye, a lemur.

To verify the identity of these tiny jaws, other researchers at Duke University took microCT scans of the jaws of 42 living and extinct animals groups, including bats, treeshrews, and primates. They then compared the shape of their teeth to P. leakeyi using a computer program. In addition, more than 395 anatomical features and 79 genes for 125 mammal species, living and extinct, were compared.

The researchers found that P. leakeyi shared features with a similar primate that lived 34 million years ago in Egypt called Plesiopithecus teras — also a relative of the aye-aye. The aye-aye is one of the earliest known species of lemur. It is a small, nocturnal primate and the only primate with rodent-like dentition, which it uses to bore wood to search for insects.

The aye-aye. Image credit: David Haring.

This discovery questions the current theory of how lemurs evolved. The original theory states that all the lemurs migrated to Madagascar at the same time, more than 60 million years ago. The presence of the fossils could mean that two different types of lemurs had already evolved in Africa before migrating to Madagascar. One type may have evolved into the aye-aye, and the other type may be the origin of the hundred other species of lemurs. This conclusion makes some sense, as, at the time, the sea levels were lower, so lemurs would have less distance to travel. It’s fascinating that so much about this fossil has been uncovered after so many years in storage.

Journal reference: “Fossil Lemurs From Egypt and Kenya Suggest an African Origin for Madagascar’s Aye-Aye,” Gregg F. Gunnell, Doug M. Boyer, Anthony R. Friscia, Steven Heritage, Fredrick Kyalo Manthi, Ellen R. Miller, Hesham M. Sallam, Nancy B. Simmons, Nancy J. Stevens, Erik R. Seiffert. Nature Communications, August 21, 2018.

Natural preservatives are more effective and healthy than artificial preservatives

Artificial preservatives are used to make food last longer. However, it comes at a cost. Preservatives used to keep meat fresh have been linked to thyroid troubles and cancers. Scientists from the Nanyang Technological University in Singapore have discovered how to create a plant-based preservative that is actually more effective than artificial preservatives.

Flavonoids are phytonutrients that are found in almost all fruits and vegetables. They give produce, such as strawberries, kale, and grapes, their bright colors. Otherwise, they defend plants against pathogens, pests, and environmental stress. They have already been known to be antimicrobial, but have not been used in food production because they would require another cost and time intensive processing step to defend against bacteria.

The breakthrough here is that the researchers found an easier way to extract flavonoids by implanting the flavonoid-producing mechanism from plants into baker’s yeast. The yeast then produced the flavonoids. It is a similar procedure to manufacturing vaccines using yeast. This new process yields flavonoids that have greater antimicrobial properties than samples taken directly from plants and the added bonus of antioxidant properties.

Preservatives are added to fruit juices to make them stay fresh longer. Image credits: Pixnio.

“Antimicrobial and antioxidant properties are key elements in food preservation. Flavonoids extracted directly from plants need to be further processed to be antimicrobial whereas our flavonoids produced from yeast do not require this. Secondly, there have been no reports on antioxidant properties in flavonoids while our yeast-based flavonoids naturally come with it,” said Professor William Chen, Director of NTU’s Food Science & Technology programme.

These flavonoid-based preservatives were tested on meat and fruit juice samples. The food samples were treated with the new natural preservative and artificial preservatives, and left at room temperature. The food treated with the flavonoid-based preservative stayed fresh for two days, while the food treated with artificial preservatives only lasted about six hours before being colonized by bacteria.

“This organic food preservative is derived from plants and produced from food grade microbes, which means that it is 100 percent natural. It is also more effective than artificial preservatives and does not require any further processing to keep food fresh,” said Prof Chen.

The researchers are already developing their technique to be used in the food industry. Hopefully we will be seeing these all-natural preservatives in packaged food in the near future.

Journal reference: Kuan Rei Ng, Xiaomei Lyu, Rita Mark, Wei Ning Chen. Antimicrobial and antioxidant activities of phenolic metabolites from flavonoid-producing yeast: Potential as natural food preservatives. Food Chemistry, 2019; 270: 123 DOI: 10.1016/j.foodchem.2018.07.077.

 

Tiny phytoplankton may be able to change the weather

Most phytoplankton aren’t visible to the naked eye. However, one species of phytoplankton, Emiliania huxleyi, is so abundant that its blooms can be seen from space. Now, scientists from the Weizmann Institute of Science in Israel have found that this phytoplankton could be indirectly responsible for reflecting sunlight and creating clouds.

E. huxleyi bloom seen from space. Image credits: Steve Groom, en:Plymouth Marine Laboratory.

When Emiliana huxleyi blooms, it is often infected by the virus EhV, which breaks up the bloom. The phytoplankton is composed of tiny, intricate plates of calcium carbonate. When infected, parts of these chalky shells are released into the air when bubbles in the ocean burst. These particles are not the only ones released from the ocean: a number of others are also released in the same way. They act as aerosols in the atmosphere which can start cloud formation and reflect solar energy.

“This study demonstrates that oceanic microbial interactions affect key atmospheric processes. It also suggests that coccoliths may by key contributors to coarse mode sea spray aerosol, and may participate in important chemical reactions in the marine atmosphere, and in cloud formation processes,” commented commented Dr. Miri Trainic from the Weizmann Institute of Science to ZME Science.

The structure of E. huxleyi. The little plates fall off and can become airborne when the phytoplankton is infected by a virus. Image credits: Alison R. Taylor (University of North Carolina Wilmington Microscopy Facility).

Although it was known that E. huxleyi’s particles could act as aerosols, they have a much greater impact than expected. The researchers observed a model system in the laboratory and found the phytoplankton produced particles four times larger than expected and were very abundant. These characteristics, along with the particle density, indicate that they could be more influential in affecting atmospheric conditions than originally thought.

“What we found was that we don’t need to look at just the size of the [particle], but also its density,” says Assaf Vardi, an environmental scientist at the Weizmann Institute of Science. “These ones are shaped like parachutes; they have an intricate structure of calcium carbonate with lots of space within it, which extends the particle’s lifetime in the atmosphere.”

The next step for the scientists is to study this phytoplankton and its particles in the atmosphere to understand the relationship of these particles with the natural world. The world is such an interesting and complex place: even a single-celled organism can influence the climate.

Journal reference: Trainic, et al.: “Infection dynamics of a bloom-forming alga and its virus determine airborne coccolith emission from seawater”, iScience

New pesticide found to be as harmful to bumblebees as used pesticides

Agriculture currently faces a huge conundrum: pesticides kill the pests that would damage or destroy our crops, but these pesticides are killing the very pollinators that make agriculture possible. Recently, it has been discovered that the widely used neonicotinoid pesticides cause bee population declines. After much debate, three of these pesticides are now banned in Europe and two will be phased out in Canada. The question of how to safely protect these crops against pests still remains. A new class of pesticides based on sulfoximine is being suggested as an alternative. However, a new study published in the journal Nature has just reported that these pesticides could be just as harmful as the ones that they are replacing.

Bee reproduction affected

Bumblebees were exposed to low doses of the new pesticide in the lab (similar to what they would be exposed to in an agricultural field) and transferred to a field. Their reproductive output was severely compromised: fewer workers and only half as many reproductive male bumblebees were produced. This is a drastic impact and would affect wild bumblebee population immediately if put into widespread use.

Besides being useful at pollinating, bumblebees are pretty darn cute. Image credits: Pixabay.

“This study shows an unacceptable scale of impact on bumblebee reproductive success, after realistic levels of exposure to sulfoxaflor,” commented Lynn Dicks, a Natural Environmental Research Council Fellow at the University of East Anglia.

Bigger picture

From the results of this experiment, the new sulfoximine-based pesticide is not a viable alternative for currently used pesticides. The study also highlights the importance of conducting these sorts of studies before approving a pesticide for widespread use. Indeed, two sulfoxaflor-based pesticides were already approved by the US Environmental Protection Agency in 2013; many other countries have also registered this pesticide for use. Hopefully this study will convince the prohibition of this pesticide as well; after all, using a pesticide that harms bees is self-sabotage in the long run.

It is a tricky situation and there aren’t any magic solutions at the moment. Most arthropods have such conserved systems that it is difficult to selectively target only a group of them. If a pesticide is harmful to a pesky group of arthropods, it is usually also harmful to other useful ones, such as pollinators and stream invertebrates. Other pollinator-friendly alternatives to protect crops need to be explored immediately.

Journal reference: Harry Siviter et al. Sulfoxaflor exposure reduces bumblebee reproductive success, Nature (2018). DOI: 10.1038/s41586-018-0430-6

 

Lizards can only regrow imperfect tails due to faulty stem cells

Although humans cannot regrow body parts after they are lost, some animals have the impressive ability to regrow a tail or leg like nothing has happened. A salamander can lose a tail to a hungry bird and regenerate a new tail that is indistinguishable from the old tail. Lizards can also regrow a lost tail, but the new tail isn’t the same as the old one. Scientists at the University of Pittsburgh were interested in seeing what the difference is between the two animals and transplanted stem cells from a salamander to a lizard.

Comparing the regeneration abilities of salamander, lizard, and mouse tails. Image credits: Thomas P. Lozito.

“The traditional animal model for regeneration is the salamander,” said senior author Thomas P. Lozito, Ph.D., assistant professor in Pitt’s Department of Orthopaedic Surgery, Center for Cellular and Molecular Engineering and the McGowan Institute for Regenerative Medicine. “Salamanders can regenerate a wide variety of tissues – brain, heart, parts of their eyes, limbs, tails – but they have whole classes of molecule types and tissues that just aren’t found in mammals, so we really haven’t been able to apply very much of what we found in the salamander to humans.”

A lizard with a newly grown tail. Image credits: Francois Mignard.

Lizards have more similar tissue types to humans and are thus a better model for examining regeneration in humans. Although they can still regenerate some tissues, they aren’t perfect at it. They can also regrow lost tails but they are different inside out. The scales and color are different as well as the tissues inside. The regenerated tails also do not contain any bones, only cartilage. The difference between the perfectly regenerating salamander and the not-so-perfect lizard could help reveal what actually determines whether an animal is able to regenerate.

The scientists transplanted neural stem cells from a salamander to the tail stump of a lizard. Neural stem cells can differentiate in neurons or glia, the cells that surround neurons. Lizards with the salamander stem cells were able to produce many cell types, including neurons. However, lizards with their own stem cells only produced glial cells. Therefore, the neural stem cells in lizards are not true neural stem cells because they only form one type of cells.

The neural stem cells are the key that define the difference between the perfect regeneration in salamanders and the imperfect regeneration in lizards. The stem cells in lizards can only produce one tissue type and thus result in imperfect tails. These cells make all the difference and could be important in causing tissue regeneration in other animals.

Journal reference: Sun et al. 2018 Proceedings of the National Academy of Sciences.

Flowers have likely been producing heavenly scents for millions of years

Nestling your nose into a bouquet of flowers, you can enjoy not only the beauty of the flowers, but their delicate olfactory notes. Flowers 100 million years ago looked very different than they do today—they did not have colorful petals then. However, new research shows that looks aren’t everything and these ancient plants still produced attractive scents.

A father-son duo (an entomologist at Oregon State University, George Poinar Jr. and his son Greg, a fragrance collector) examined ancient flowers that have been preserved in Burmese amber for millions of years. Although they don’t have a scent anymore, tissues that are known produce the scents are still present in the fossilized flowers. Therefore, the relevant tissues and flower-based aromatic compounds have been around since the mid-Cretaceous period.

An ancient flower preserved in amber. Image credits: Oregon State University.

Indeed, scent was even more important for these ancient flowers because they didn’t have any flashy flower petals that could aid in attracting pollinators. So they needed to smell very attractive.

“It’s obvious flowers were producing scents to make themselves more attractive to pollinators long before humans began using perfumes to make themselves more appealing to other humans,” said George Poinar.

In one respect, these ancient flowers are not so far removed from modern-day flowers. The tissue that secreted the fragrances is very similar to the tissue found in modern plants. Perhaps, then, they also produced similar fragrances to today’s flowers.

Who knows, maybe even a dinosaur enjoyed a whiff of a prehistoric flower every now and then.

Journal reference: George Poinar et al, “The antiquity of floral secretory tissues that provide today’s fragrances”, Historical Biology (2018). DOI: 10.1080/08912963.2018.1502288

Bermuda fireworms glow in a one-of-a-kind way

Bermuda fireworms (Odontosyllis enopla) were described by Christopher Columbus in 1492 as “looking like the flame of a small candle alternately raised and lowered.” These worms glow a striking green-blue color before mating. Researchers from the American Museum of Natural History looked at this phenomenon on a molecular level to see what exactly causes these fireworms to glow.

The fireworms only glow during the mating season. The females have a spookily accurate sense of time and always start to glow a blue-green color 22 minutes after sundown on the third night after a full moon, throughout the summer and autumn. The tantalizing glow then attracts the males.

The Bermuda fireworm. Image credits: © James B. Wood.

“The female worms come up from the bottom and swim quickly in tight little circles as they glow, which looks like a field of little cerulean stars across the surface of jet black water,” said Mark Siddall, a curator in the American Museum of Natural History’s Division of Invertebrate Zoology and corresponding author of the study. “Then the males, homing in on the light of the females, come streaking up from the bottom like comets–they luminesce, too. There’s a little explosion of light as both dump their gametes in the water. It is by far the most beautiful biological display I have ever witnessed.”

The researchers analyzed the full set of RNA molecules from twelve female Bermuda fireworms. They found that the worms glow due to a luciferase enzyme. Although luciferases are already known to be responsible for bioluminescence in many organisms — such as copepods, fungi, and jellyfish — this particular enzyme is new! It is especially exciting that this particular enzyme has never been seen before, because it could potentially be used as a tagging molecule in biomedical research, to track the movement of certain factors in cells, for example.

The researchers were also interested in how the timing of the mating display may be linked to other physical or genetic changes in the worms. Just before mating, the worms prepare themselves by enlarging their eyes and modifying the organ that stores and releases gametes. After mating, these changes reverse themselves. These worms are pretty fascinating, and perhaps the most punctual maters of all time! It would be interesting to learn more about the genetic cues for beginning the glowing process.

 

Annual killifish get the prize for youngest sexually mature vertebrate

Annual killifish (Nothobranchius furzeri) have a live-fast-die-young type of lifestyle. The fish embryos survive in a dried inactive state in sediment. When it rains, they are activated, somewhat like plant seeds. Therefore they need to hatch, mature, and produce offspring on a ticking clock before the pools dry up. Scientists have found that this lifestyle has caused the killifish to become the fastest maturing vertebrate.

Previously, only laboratory studies have examined the lifestyle of the killifish and it turns out that they have underestimated their lifespan. In the lab, the fish live on average three to four weeks, though it can take up to ten weeks. It can be rather variable and the researchers suspected that the fish might mature even quicker in natural populations.

An annual killifish. Image credits Leibniz Institute for Age Research – Fritz Lipmann Institute (FLI), Jena, Germany,

“We guessed that some populations of this species could achieve very rapid growth and sexual maturation under particular conditions,” says Martin Reichard of the Institute of Vertebrate Biology, The Czech Academy of Sciences. “But we have found that this rapid maturation is the norm rather than a rare exception.”

How the fish and their habitat look like after 1, 2, and 3 weeks. Image credits: M. Vrtílek, Ják, M. Reichard.

The research team surveyed killifish in the wild across southern Mozambique. Fish were collected from eight pools within three weeks after the pools filled with rainwater. By comparing the age of the fish with the time of pool filling, it was determined that the fish hatched from their eggs after three days of being immersed in water. By analyzing the fish’s gonads, the researchers found that they were sexual mature after a mere 14 or 15 days.

So, these fish hatch at under a millimeter in size and grow to full size, four or five centimeters, and start reproducing after only two weeks! They receive the prize for the youngest vertebrate parents.

Journal reference: Vrtílek et al. 2018. Extremely rapid maturation of a wild African annual fish. Current Biology.

New 3D model treats avalanches as both solid and liquid to get most accurate results

Avalanches are complex, and often unpredictable events. Researchers from the Laboratory of Cryospheric Sciences and Swiss Federal Institute for Snow and Avalanche Research have shed light on how avalanches form and transpire. With the help of 3D modeling experts (some of whom worked for Disney to help simulate the snow in the animated movie Frozen), they created an accurate model of an avalanche, which could help predict avalanches in the future.

The combination of 3D simulations, scientific data, and field observations led to the birth of this accurate model of a snow slab avalanche. This especially dangerous and unpredictable avalanche type occurs when the layers of snow are unstable — there is usually a weak snow pack layer under the dense top snow layer. A small trigger, such as a person skiing or walking over the snow, can cause a large crack to form in the top layer of the snowpack and initiate the avalanche.

Image credits: Chagai.

The key to modeling the avalanche was to account for the snow’s behavior as both a liquid and a solid. When a trigger causes a crack to form in the snow layer, it spreads rapidly and the snow acts as a solid. However, the spreading crack causes the weak snow pack layer to collapse. The heavy top layer (the slab) is then released and slides down, now acting like a fluid.

The researchers used a technique called the Material Point Method to model the avalanche, which was previously used to analyze the behavior of moving objects. The same technique was used to develop the algorithm “Matterhorn”, which created simulations of how various types of snow behaves. You’ve probably seen it in action as the snow in Disney’s animated movie Frozen.

“In addition to deepening our knowledge of how snow behaves, this project could make it possible to assess the potential size of an avalanche, the runout distance and the pressure on any obstacles in the avalanche’s path more accurately,” says lead reseaercher Johan Gaume of the Laboratory of Cryospheric Sciences and Swiss Federal Institute for Snow and Avalanche Research.

The novel approaches implemented in this study enabled the creation of an accurate avalanche model. This model can be used to predict and prevent avalanches, and can also be used to simulate snow in animated films.

Journal reference:  J. Gaume, T. Gast, J. Teran, A. van Herwijnen,C. Jiang. 2018. Dynamic anticrack propagation in snow, Nature Communications.

 

Naked mole-rat kings and queens challenge what we know about aging

Naked mole-rats are known for their, um, interesting appearance, but it turns out they are of interest to scientists for other reasons (such as being able to live without oxygen for 18 minutes). They live in social colonies (somewhat similar to bees) and the queen and king actually live the longest in the colony, despite carrying the entire colony’s reproductive costs. This defies what we know to be true in almost every other animal: reproduction decreases lifespan. Researchers from the Leibniz Institute on Aging in Germany examined their genetics to find out why.

Naked mole-rats live in colonies comprised of a breeding pair (the king and queen, who are the only ones that reproduce) and up to 300 sterile workers. The king and queen are fertile from the age of one until their deaths, and they can live for up to 18 years. The sterile workers gather food, take care of the young, and maintain and guard the nest. When the king and queen die, other members of the eusocial colony take over and sexually mature.

Naked mole-rat. Image credits: Buffenstein/Barshop Institute/UTHSCSA.

“Our results indicate that when naked mole-rats mature into breeders, it changes their aging rates, meaning that breeders are able to live longer than non-breeders. This is surprising, as evidence from other species suggest that reproduction, which ensures the survival of the species as a whole, reduces the lifespan of the individual. In naked mole-rats reproduction appears to prolong the breeders’ lifespan. This goes against the common expectation that mammals either invest resources in a long life or in reproduction,” said the corresponding author Dr. Martin Bens.

The researchers compared the genes for a range of organs in breeding and nonbreeding naked mole-rats, as well as for guinea pigs, which are close relatives. Aging related genes in breeding mole-rats were differentially expressed as compared to nonbreeding mole-rats and guinea pigs. For example, a muscle regeneration gene is more strongly expressed in breeding naked mole-rats. These differences may be responsible for the long lifespan of breeders.

Interestingly, there were no differences between male and female workers. However, a big difference arises if they become breeders. When the researchers took a male and female worker from the colony and put them together in a separate place, they changed into breeders. They suddenly became sexually dimorphic and had the associated changes in gene expression tied to increased lifespan and health. Becoming sexually active actually changes them at a molecular level! They then get a load of health benefits — presumably to help them maintain a colony.

Journal reference: Bens et al. Naked mole-rat transcriptome signatures of socially-suppressed sexual maturation and links of reproduction to aging. BMC Biology 2018. DOI: 10.1186/s12915-018-0546-z

Long-term exposure to sunscreen chemicals disrupts zebrafish embryo development

It’s summertime, and for many people that means lying on a beach, going hiking, or other outdoor activities. Using sunscreen is the easiest way to protect the skin against sunburns and skin cancer. It has recently come to light that the chemicals used to filter out ultraviolet (UV) light have negative effects on marine life. A new study published in Environmental Science & Technology shows that the combination of UV filters in water can be more dangerous to fish than the individual presence of UV filters.

Image credits: Public Domain Pictures.

Most commercial sunscreens contain chemical UV filters that absorb the rays and keep them from reaching skin. Oxybenzone and octinoxate are two chemicals often used in sunscreens that are known to damage corals and impede the development of marine creatures. In general, most studies have shown that the current concentrations of individual UV filters are not so dangerous for humans or animals. Kelvin Sze-Yin Leung decided to test the long-term effects of combinations of UV filters.

Leung and his research team chose Shenzhen as the site for their study because it has a large growing urban population and more than 20 public beaches. They analyzed the levels of nine common UV filters in surface water. Seven of the nine chemicals were found in sea water, and even in reservoir and tap water. Their levels were high in most locations throughout the whole year.

Zebrafish embryo. Image credits: Nikita Tsyba in cooperation with Azamat Bashabayev.

In a lab experiment, the researchers fed zebrafish brine shrimp that had been exposed to three common UV filters, separately and in combination. There was a short-term (25 days) and long term (47 days) treatment. The short exposure did not affect the zebrafish’s offspring, but the 47 day exposure disrupted embryo development. Fish embryos exposed to all three chemicals had a decreased heart and hatching rate and changes in enzyme activity. The level of UV filters found in the fish that were exposed to the chemical mixtures was up to four times higher than in fish that were exposed to just one chemical.

In all, this study has shown that these UV filters are prevalent in the waters of Shenzhen and that the combination of different UV filters can be more dangerous than single chemicals.

Journal reference: Jing Li, A., Cheuk-Fung Law, J., Chow, C., Huang, Y., Li, K., & Sze-Yin Leung, K. Joint Effects of Multiple UV Filters on Zebrafish Embryo Development. Environmental Science & Technology Article. DOI: 10.1021/acs.est.8b02418

Wings

CRISPR was used to change a butterfly’s wing color

Butterflies have complex color and scale patterns that allow them to camouflage, attract mates, or warn predators. Researchers used CRISPR/Cas9 to study the genes of one butterfly species to see how they contribute to the wing color and scale structure. Surprisingly, they found that the scale and color of the wings are linked to the same genes.

Wings

The wings of each melanin gene mutant.
image credits

The squinting bush brown butterfly, Bicyclus anynana, comes from East Africa and is typically a dark brown color. A postdoctoral fellow at the National University of Singapore, Yuji Matsuoka, disabled five of the butterfly’s pigment genes with CRISPR/Cas9. CRISPR is a new gene editing system that is capable of adding and disabling genes to different organisms easily and cheaply. The mutations not only changed the color of the butterfly to a light brown/yellow, but also altered the wing scale structure.

“Our research indicates that the color and structure of wing scales are intimately related because pigment molecules also affect the structure of scales,” says senior author Antónia Monteiro, a biologist at the National University of Singapore’s Faculty of Science and Yale-NUS College in Singapore. “Some end products of the melanin pathway, which produces butterfly wing pigments, play a role in both scale pigmentation and scale morphology.”

One mutation prevented the manifestation of the pigment dopa-melanin and it also caused an extra sheet of chitin to form horizontally on the upper surface of the wing scale. However, when the different pigment dopamine-melanin was mutated, there were suddenly vertical blades of chitin. This work shows that butterfly color and scale structure are intimately linked and seem to work together. These fives genes could constrain the evolution of a butterfly’s color.

The wildtype butterfly (left) and with mutations (right).
Image credits: William H. Piel and Antónia Monteiro.

The morphology of wing scales is very different between butterfly species. Melanin seems to be an important molecule in this process and it is likely not the only one. These results also help us to know more about the development and evolution of butterfly wing scales.

“Some butterflies can have vivid hues just by having simple thin films of chitin on their scales that interfere with incoming light to create shades known as structural colors without producing corresponding pigments,” says Monteiro. “Light beams reflecting off the top and bottom surfaces of the chitin layer can interfere with each other and accentuate specific colors depending on the thickness of the film, so our results might be interesting in this context.”

One interesting application of this result could be to bioengineer bright colors based on butterfly scales in the future. Above all, this discovery helps us to better understand butterfly coloration and wing scale structure.

Journal reference: Matsuoka et al. 2018. Melanin Pathway Genes Regulate Color and Morphology of Butterfly Wing Scales. Cell Reports.

A “textbook changing” new form of photosynthesis has been discovered

For those of you who think that we know it all already, there’s a new surprise. A recent discovery has shaken what know about photosynthesis, an already well-studied topic. The “textbook changer” is that a group of photosynthesizers exists that does not need visible red light. This was thought to be impossible because light below these wavelengths does not contain much energy.

It is very well established that photosynthetic organisms use visible red light for photosynthesis. The green pigment, chlorophyll-a, is used to collect red light and use its energy to make necessary biochemicals and oxygen. Chlorophyll-a is found in pretty much every single photosynthetic organism, so we thought that it sets an energy limit for photosynthesis. This has been termed the “red limit” and was thought to signify the minimum amount of energy required for the process of photosynthesis.

One cyanobacterium, Acaryochloris, that lives in the shade of a green sea squirt that blocks most visible light is known to use near-infrared light. It was considered an exception as it is a single species and lives in an extremely specific habitat. Now, the researchers have discovered that it isn’t just a one-off, but actually a quite common lifestyle for cyanobacteria that live in shaded areas. A few examples are found in bacterial mats in Yellowstone Park and in Australian beach rock.

Colony of cyanobacteria where magenta represents chlorophyll-a driven photosynthesis and yellow represents chlorophyll-f driven photosynthesis. Credit: Dennis Nuernberg.

So how are these cyanobacteria able to survive if they can’t power their chlorophyll-a? It turns out that chlorophyll-a shuts down under these circumstances and lets its sidekick chlorophyll-f take over. Previously, chlorophyll-f was thought to just harvest light, now we know that it takes a starring role under shaded conditions and can use infrared red light to perform photosynthesis below the red limit. Plants that use this photosynthesis type can also protect themselves from varying brightness of light.

“The new form of photosynthesis made us rethink what we thought was possible. It also changes how we understand the key events at the heart of standard photosynthesis. This is textbook changing stuff,” said lead researcher Professor Bill Rutherford, from the Department of Life Sciences at Imperial College London.

Now we know of a third widespread type of photosynthesis. It is only employed in special conditions, in infrared-rich shaded conditions. When there is normal light, standard photosynthesis is still the norm.

So what are the consequences of this discovery? The researchers think that it could help to engineer more efficient crops that can use a wider range of light. Another interesting implication is that is could lower our standard, so to speak, to search for life on other planets. Until now, the red limit is used in astrobiology to determine whether complex life could have evolved in other solar systems.

It’s pretty cool that there are major discoveries to be made on topics that we think that we know well!

Journal reference: Dennis J. Nürnberg et al, Photochemistry beyond the red limit in chlorophyll f–containing photosystems, Science (2018). DOI: 10.1126/science.aar8313

Platypus hormone could be useful in treating type 2 diabetes

Nature contains a trove of substances that could be useful in human medicine. Now a key metabolic hormone has been found in the venom and gut of the platypus that has the potential to treat type 2 diabetes. Researchers from the University of Adelaide examined the platypus genome, which was sequenced in 2008, and learned more about the genes present in platypuses.

“One of the most amazing discoveries of the platypus genome project was the massive loss of genes important for digestion and metabolic control – these animals basically lack a functional stomach,” said project leader Professor Frank Grutzner, from the University of Adelaide.

The metabolic hormone called glucagon-like peptide-1 (GLP-1) is seen as an important substance in treating diabetes. It is usually secreted in both human and animal guts and stimulates the release of insulin to lower blood glucose. Exenatide, a modified form of this hormone, is commonly used to treat diabetes.

Image credits: Brisbane City Council.

The platypus GLP-1 is very different from other types, likely due to its function in their venom, as well as in the gut. The platypus GLP-1 therefore functions differently and doesn’t degrade as quickly as the type found in humans. These features could make it a more effective treatment option.

“We have privileged access to these amazing animals,” says Professor Grutzner. “Male platypuses produce venom during the breeding season, and can deliver the venom from their hind spurs. We were surprised to see GLP-1 present in venom and think that this may have led to a more effective hormone.

The hormone has just been identified as being useful and needs to go through testing and clinical trials to see if it is actually a viable diabetes treatment option. However, its viability as a treatment option also depends on whether it can be produced synthetically as platypuses are “near threatened” and pressure on their wild populations could make them endangered.

 

A new way to know if you’ll catch the flu

Uh-oh, there’s a flu virus going around and you’re worried that you will get sick. There may be a simple way to know if you are actually susceptible. Researchers from the Stanford University School of Medicine have found a biomarker that is very accurate in predicting whether someone will become infected with a flu virus or not.

From analyzing thousands of immune cell samples and using an experimental approach, the researchers found, for the first time, an important biomarker that holds across multiple strains of influenza. The biomarker is a gene called KLRD1 and it is connected to the presence of immune cells that fight off flus. The more cells with this biomarker that a person has, the less likely that they are to get the flu.

Image credits: Pixabay.

The researchers analysed data collected from over 150 studies that monitored the gene expression of immune cells. They looked at 20 immune cell types to see if any of them showed a consistent response to the H1N1 or H3N2 flu. If they did, then the researchers looked at their genes as well. Additionally, there were two experimental studies, one at Harvard University and one at Duke University in which, crazily enough, 52 participants volunteered themselves to be exposed to influenza. Their immune cells were then quantified.

“We found that a type of immune cell called a natural killer cell was consistently low at baseline in individuals who got infected,” said lead author Erika Bongen. The participants with a higher proportion of natural killer cells had a better immune system and were less likely to get sick.

The gene KLRD1 was a good proxy for these natural killer cells. It expresses a receptor on the surface of the natural killer cells and thus helps count how many of these immune cells that there are in the body. People whose immune cells consisted 10-13% of natural killers did not become infected, while those with less than 10% got sick. This was true in all of the cases.

The researchers do emphasize that the link between KLRD1 levels and influenza is just an association for now. They don’t know exactly how both are linked. The next step in the research is to find the mechanism for why this is the case.

“It will be crucial to understand the role of natural killer cells’ protection so that we can potentially leverage that in designing better flu vaccines,” said Purvesh Khatri, Ph.D., associate professor of medicine and of biomedical data science at the Stanford University School of Medicine. “Since we see that natural killer cells are protective across different strains, maybe that would be a path to a universal flu vaccine.”

In addition to helping to develop a vaccine, these findings can also help by identifying who is the most susceptible to the flu and should take preventative measures.

Bongen et al. 2018. KLRD1-expressing natural killer cells predict influenza susceptibility. Genome Medicine.

 

Restoring forest habitat has filled Missouri forests with birdsong again

Humans have destroyed many natural habitats and the animals that used to live there are suffering. Restoring these habitats is a way to help out its inhabitants, though it can be hard to see if this actually works. Because birds living in Missouri have been in decline, there have been efforts made to restore the forests. A monitoring project alongside the restoration efforts shows that bird survival has gone way up in the restored habitats. These results are published in The Condor: Ornithological Applications.

The typical type of forest in Missouri was pine savanna and woodland areas. The forests were very open with trees dispersed across grasslands. Forest fires in particular were responsible for these habitat types. Native Americans had regularly set fires to promote the resources that supported their livelihoods, such as those for hunting, crops, and warfare. Therefore, there was a mosaic of grasslands and forest, supporting a large amount of biodiversity. However, the Europeans decimated Native populations and started a fire suppression policy upon their arrival.

Pine savanna in the USA. Image credits: NOAA.

Habitat restoration involves using the Native technique of fire clearing, with so-called prescribed fires. Additionally, some of the forest strands have thinned. This study, examining restored pine woodland in the Midwest, is unique as previous work has focused on oak savannas in the Midwest and longleaf pine savannas in the eastern US.

Researchers followed the birds’ survival as restoration progressed. Melissa Roach from the University of Missouri and her colleagues looked at the survival of six bird species over two years. Three of them nest in shrubs, the Eastern Towhee, Prairie Warbler, and Yellow-breasted Chat, and three in the canopy, included Eastern Wood-Pewee, Pine Warbler, and Summer Tanager.

“The thought is that the dense shrub layer created by the restoration of pine woodland increases both nest concealment and the number of potential nest sites. This would force predators to search harder and longer for nests; therefore, decreasing the chance of any one nest being found. It’s also likely that predators are taking advantage of an abundance of alternative prey such as small mammals, reptiles, and invertebrates that are supported by the diverse and lush vegetation,” said Melissa Roach to ZME Science.

Before the restoration, predation was the main reason why chicks did not survive. The open forest floor allowed predators to find the chicks easily. Now, forest thinning and fire has created a landscape with multiple vegetation types, changing the dynamics between predators and prey. Shrub and canopy birds have benefitted almost equally. The result is that more animal species are able to coexist in the forest and songbirds are doing better.

Prairie warbler. Image credits: Andy Reago & Chrissy McClarren.

“There are multiple big picture implications from this study. The first being that restored pine savanna and woodland is benefitting a variety of bird species, some of which are species of concern, even when bird conservation was not the primary focus of the restoration plan. While our six focal species were common in this study, four are species of conservation concern and some, like Summer Tanagers and Pine Warblers, even have limited reproduction data. Not only were we able to show that these species are responding positively to pine woodland restoration, we provided baseline nest survival data for some understudied species. We hope that land managers can directly apply this information when choosing the type and frequency of restoration treatments, and we also hope that this study increases the public’s awareness and appreciation of just how important prescribed fire and tree thinning can be for wildlife,” said Melissa Roach to ZME Science.

Habitat restoration, if done properly, can really help local species to thrive again.

Journal reference: Roach et al. 2018. Songbird nest success is positively related to restoration of pine-oak savanna and woodland in the Ozark Highlands, Missouri, USA. The Condor: Ornithological Applications.

Why we need sleep– a molecular answer

It’s funny, although we spend about a third of our lives doing it, we don’t know exactly why we need to sleep. There are a number of different theories—that we sleep to conserve energy, for brain plasticity, or for evolutionary reasons. Whatever the true purpose of sleep may be, researchers are delving deeper into the molecular reasons behind why we have the desire to go to sleep, and, in the process, could shed light on the purpose of sleep as well.

Qinghua Liu and colleagues studied the molecular need for sleep by developing a special type of mutant mouse. The mutant genotype was called Sleepy, like Snow White’s dwarf, and had a single mutation in the Sik3 gene. These mice had a much higher need to sleep although they slept a lot. Their brains showed a ton of phosphorylation, similar to those in sleep-deprived mice. The mutant protein in Sleepy mice phosphorylates at a greater rate.

“To study the molecular basis of sleep need, we devised a novel strategy of comparing phosphorylation in the brains of the sleep-deprived normal mice and Sleepy mutant mice. In Sleepy mice, a single nucleotide mutation of the salt-induced kinase 3 (Sik3) gene, a member of the AMP-activated protein kinase family, results in constitutively high sleep need and chronic hypersomnia. Whereas sleep deprivation increases wake time, Sleepy mutation decreases wake time; yet both increase sleep need. Thus, these mice are two opposite models of increased sleep need. We hypothesize that cross-comparison of these two models will allow us to zero in on the specific phosphorylation changes associated with sleep need by filtering out non-specific effects of prolonged sleep, wake, and stress, which can never be achieved by either model alone,” said Liu to ZME Science.

Image credits: Public Domain Photos.

Phosphorylation entails the attachment of a phosphoryl group to a molecule. It is an important regulatory mechanism in living organisms that is usually reversible. Phosphorylation and dephosphorylation function as “on” and “off” switches for a variety of different enzymes and receptors.

By comparing Sleepy and sleep-deprived mice, the researchers were able to identify 80 synaptic proteins that were phosphorylated due to a lack of sleep and named them Sleep-Need-Index-Phosphoproteins (SNIPPs). Comparing these two mouse types filtered out confounding effects and they could see what really changed on a molecular basis. High phosphorylation levels in the brain increased the need for sleep and sleeping lowered phosphorylation levels.

“A holy grail of sleep research is to identify the actual molecular factor or factors involved in sleep. We found that the phosphorylation of SNIPPs increased along with sleep need and dissipated, or dephosphorylated, throughout the brain during sleep.  Previous studies suggested a close link between sleep need and synaptic plasticity (the strengthening and weakening of synaptic connections between neurons that is linked to thinking and learning). Intriguingly, the majority of SNIPPs are synaptic proteins, including many regulators of synaptic plasticity. Thus, we propose that SNIPPs constitute the molecular interface between synaptic plasticity and regulation of sleep need, or in lay terms, between thinking and sleepiness.
The phosphorylation/dephosphorylation cycle of SNIPPs may be an important way for the brain to reset itself every night, restoring both synaptic and sleep-wake balance to maximize clear thinking,” explained Liu to ZME Science.

Synapse phosphorylation seems to be a sign that you need sleep. These results are interesting because they match up with the synaptic homeostasis hypothesis, which proposes that sleep allows synapses to recover from their daily activity and keep everything going stably. When you’re awake memories are encoded and synapses fire, while during sleep memories are consolidated and synapses are brought back to homeostasis by scaling back excitatory synapses.

These findings add to our knowledge about sleep and provide concrete targets for drugs that can treat sleep disorders.

Journal reference: Liu et al. 2018. Quantitative phosphoproteomic analysis of the molecular substrates of sleep need. Nature.

Whale sharks are very picky about where they live, which could be bad for their survival

Whale sharks are gentle giants—they are the world’s largest fish at up to 18 meters (60 feet) long and filter feed instead of hunting for food. Unfortunately, they are endangered and only gather in groups in a few locations around the world. Researchers examined why they choose these particular sites, hoping to come up with a way to conserve these unique sharks.

Groups of whale sharks are only found at about 20 locations, all very near the coasts of countries such as Australia, Belize, Mexico, and the Maldives. The researchers from the University of York in collaboration with the Maldives Whale Shark Research Program found what makes all of these areas special: they all have areas with shallow, warm water and a steep drop off to deep water.

The reason that these sites are so suitable for whale sharks could be that they are ideal feeding zones and the shallow water allows them to warm themselves up. The sharp drop off can cause currents to well up bring in the plankton and small crustaceans that whale sharks feed upon.

Image credits: Pixabay.

“Sharks are ectotherms, which means they depend on external sources of body heat. Because they may dive down to feed at depths of more than 1,900 metres, where the water temperature can be as cold as 4 degrees, they need somewhere close by to rest and get their body temperature back up,” said the supervising author of the study, Dr. Bryce Stewart from the Environment Department at the University of York.

Unfortunately, what makes these areas so nice for the whale sharks also makes them problematic. Swimming in shallow water makes the sharks vulnerable to being struck by a boat, which often occurs. Throughout the duration of the study, the researchers were able to track individual whale sharks by their unique pattern of stripes and spots. They found that the rate of injuries to the whale sharks was quite high.

Indeed, boat strikes, along with hunting and accidental trapping in fishnets, have led to a drastic global decline of whale sharks in the past 75 years. Hopefully, this study can help us maintain ideal whale shark habitats to balance out human and whale needs.

Journal reference: Joshua P. Copping et al. Does bathymetry drive coastal whale shark (Rhincodon typus) aggregations?, PeerJ (2018). DOI: 10.7717/peerj.4904

 

Dogs like fatty food but cats prefer carbs

There are so many different types of pet food, it can be hard to choose what is the best for your darling hound or feline. A new study has examined pet nutritional preferences to find out what they really need.

For the study, 17 healthy adult dogs and 27 cats were recruited and observed over a period of 28 days. Each day, each animal was given a choice between four food types that differed nutritionally: high-fat, high-carb, high-protein, and balanced food. However, one important factor was kept constant: all of the foods tasted equally good! Therefore, the animals ate according to their nutritional requirements and not to taste preference. The food bowl position was switched daily to prevent any food bowl bias.

The dogs were given an hour each day to eat as much as they wanted, up to a predetermined caloric threshold. Cats had constant access to food but they were also limited to a certain number of calories per day. The reason for this calorie limit was to make sure that the animals just got the calories that they needed for their metabolism and to maintain weight.

Image credits: Max Pixel.

In the end, dogs got 41% of their calories from fat and 36% from carbs, while cats got 43% from carbs and 30% from protein. This result is in contrast to the widely held belief that cats need a lot of protein. A possible reason for this difference in results is that previous studies have used food that tastes different. In this case, cats do eat more protein and dogs eat a lot of fat. However, no dog or cat got the highest percentage of its calories from protein.

“The numbers were much different than what traditional thinking would have expected,” said the study’s corresponding author, Jean Hall, a professor in the Carlson College of Veterinary Medicine at Oregon State University. “Some experts have thought cats need diets that are 40 or 50 percent protein. Our findings are quite different than the numbers used in marketing and are going to really challenge the pet food industry.”

The animals’ age and amount of muscle also influenced what they preferred to eat. Younger cats with less muscle mass ate more protein than older cats. In contrast, young dogs ate the lowest percentage of protein, and dogs with a higher mass of body fat got more calories from protein. Old cats weren’t able to break down proteins so well and had higher amounts of catabolic products that are connected to cardiovascular and kidney disease in humans. That means that older cats shouldn’t eat so much protein because their bodies can’t deal with it and food chosen especially for older cats should contain less protein.

This study does assume that animals will choose their ideal diet when given the chance. It’s hard to say if preference necessarily means that it is better nutritionally. Some animals eat things that aren’t necessary good for them often (how do dogs always find the chocolate). Backing it up with studies on the animal’s health (like done here for the affect of protein on older cats) is also needed.

Journal reference: Jean A. Hall, Jodi C. Vondran, Melissa A. Vanchina, Dennis E. Jewell. When fed foods with similar palatability, healthy adult dogs and cats choose different macronutrient compositions. The Journal of Experimental Biology, 2018; jeb.173450 DOI: 10.1242/jeb.173450

Aggressive guppies turn their eyes black to warn other fish

If you see a Trinidadian guppy with black eyes, watch out– they’re feeling aggressive.

Well, Trinidadian guppies are pretty tiny so you don’t really need to watch out, but other smaller guppies should. Researchers from the University of Exeter and the University of the West Indies made little robo-guppies with black eyes to see how larger guppies would react to them.

Dr Robert Heathcote, lead author of the study and from the University of Exeter, said: “Trinidadian guppies can change their iris colour within a few seconds, and our research shows they do this to honestly communicate their aggressive motivation to other guppies.

A guppy with silver (lower) and black (upper) irises. Image credits: Robert Heathcote, University of Exeter.

Larger guppies usually only show black eyes to smaller guppies that they could beat in a fight, and smaller guppies don’t dare to show black eyes to larger guppies. The researchers made realistic looking small robot guppies with black eyes, which were placed to guard a food source. Then larger real guppies were introduced and competed relatively often with the black-eyed robots. The larger fish that competed also usually displayed black eyes.

All in all, the guppies then use their black eyes as a signal of aggression, and they really mean it. Smaller guppies don’t dare to show black eyes because they know that a bigger fish will take their signal seriously and fight with them, and the smaller fish don’t really stand a chance. There’s no messing around, if you make your eyes black then you have to be prepared to actually be aggressive. Therefore only dominant fish tend to show the aggressive look. Those poor robo-fish must have gotten quite the beating.

Journal reference: Heathcote et al. 2018. Dynamic eye colour as an honest signal of aggression. Current Biology.