Earth

A team of international researchers, which includes a Saint Louis University Madrid anthropologist, dug deep to find some of the oldest African DNA on record, in a new study published in Nature.

Africa is the homeland of our species and harbors greater human genetic diversity than any other part of the planet. Studies of ancient DNA from African archaeological sites can shed important light on the deep origins of humankind. The research team sequenced DNA from four children buried 8,000 and 3,000 years ago at Shum Laka in Cameroon, a site excavated by a Belgian and Cameroonian team 30 years ago.

The findings, "Ancient West African foragers in the context of African population history," published Jan. 22 in Nature, represent the first ancient DNA from West or Central Africa, and some of the oldest DNA recovered from an African tropical context. They enable a new understanding of the deep ancestral relationships among early Homo sapiens in sub-Saharan Africa.

This study was the product of collaboration among geneticists, archaeologists, biological anthropologists and museum curators based in North America (including Harvard Medical School and the Université de Montréal); Europe (Royal Belgian Museum of Natural Sciences, Royal Museum for Central Africa, Université Libre de Bruxelles and Saint Louis University's Madrid campus); Cameroon (University of Yaoundé, University of Buea); and China (Duke Kunshan University).

A unique archaeological site with exceptional preservation

Shum Laka is a rock shelter located in the 'Grassfields' region of Cameroon, a place long pinpointed by linguists as the probable cradle of Bantu languages, a widespread and diverse group of languages spoken by more than a third of Africans today.

"Linguists, archaeologists and geneticists have been studying the origin and spread of Bantu languages for decades, and the Grassfields region is key to this question," said Mary Prendergast, Ph.D., a professor of anthropology and chair of humanities at Saint Louis University's campus in Madrid, and a co-supervising author of the study. "The consensus is that the Bantu language group originated in west-central Africa, before spreading across the southern half of the continent after about 4,000 years ago."

This expansion is thought to be the reason why most people from central, eastern and southern Africa are genetically closely related to each other and to West Africans.

"Shum Laka is a reference point for understanding the deep history of west-central Africa," said Isabelle Ribot, Ph.D., a University of Montreal anthropologist who excavated and studied the burials, and is a key author of the study.

The Shum Laka rockshelter was excavated in the 1980s and 1990s by archaeologists from Belgium and Cameroon. It boasts an impressive and well-dated archaeological record, with radiocarbon dates spanning the past 30,000 years. Stone tools, plant and animal remains, and eventually pottery collectively indicate long-term forest-based hunting and gathering and an eventual transition to intensive tree fruit exploitation.

Shum Laka is emblematic of the 'Stone to Metal Age,' a critical era in west-central African history that ultimately gave rise to Iron Age metallurgy and farming. During this era, the site repeatedly served as a burial ground for families, with 18 individuals (mainly children) buried in two major phases at about 8,000 and 3,000 years ago.

"Such burials are unique for West and Central Africa because human skeletons are exceedingly rare here prior to the Iron Age," said Ribot. "Tropical environments and acidic soils are not kind to bone preservation, so the results from our study are really remarkable."

Scientists at Harvard Medical School sampled petrous (inner-ear) bones from six individuals buried at Shum Laka. Four of these samples produced ancient DNA, and were directly dated at the Pennsylvania State University Radiocarbon Laboratory. The molecular preservation was impressive given the burial conditions, and enabled whole-genome ancient DNA analysis.

A newly documented population of hunter-gatherers

Surprisingly, the ancient DNA sequenced from the four children - one pair buried 8,000 years ago, the other 3,000 years ago - reveals ancestry very different from that of most Bantu-speakers today. Instead, they are closer to central African hunter-gatherers.

"This result suggests that Bantu-speakers living in Cameroon and across Africa today do not descend from the population to which the Shum Laka children belonged," said Mark Lipson, Ph.D., Harvard Medical School, lead author of the study. "This underscores the ancient genetic diversity in this region and points to a previously unknown population that contributed only small proportions of DNA to present-day African groups."

The spreads of farming and herding in Africa - as in other parts of the world - were accompanied by many movements of people.

"If you go back 5,000 years ago, virtually everyone living south of the Sahara was a hunter-gatherer," said Prendergast. "But look at a map of Africa showing foraging groups today, and you'll see they are very few and far between."

This study contributes to a growing body of ancient DNA research demonstrating ancient genetic diversity and population structure that has since been erased by the demographic changes that accompanied the spread of food production.

A rare paternally inherited lineage with deep roots

One of the sampled individuals - an adolescent male - carried a rare Y chromosome haplogroup (A00) found almost nowhere outside western Cameroon today. A00 is best documented among the Mbo and Bangwa ethnic groups living not far from Shum Laka, and this is the first time it has been seen in ancient DNA. A00 is a deeply divergent haplogroup, having split from all other known human lineages about 300,000-200,000 years ago. This shows that this oldest known lineage of modern human males has been present in west-central Africa for more than 8,000 years, and perhaps much longer.

New light on human origins

While the findings do not speak directly to Bantu language origins, they do shed new light on multiple phases of the deep history of Homo sapiens. The researchers examined the DNA of the Shum Laka children alongside published DNA from ancient hunter-gatherers from eastern and southern Africa, as well as DNA from many present-day African groups. Combining these datasets, they could construct a model of diverging lineages over the course of the human past.

"Our analysis indicates the existence of at least four major deep human lineages that contributed to people living today, and which diverged from each other between about 250,000 and 200,000 years ago," said David Reich, Ph.D., of Harvard Medical School, senior author of the study.

These lineages are ancestral to present-day central African hunter-gatherers, southern African hunter-gatherers, and all other modern humans, with a fourth lineage being a previously unknown 'ghost population' that contributed a small amount of ancestry to both western and eastern Africans.

"This quadruple radiation--including the position of a deeply-splitting 'ghost' modern human lineage--had not been identified before from DNA," Reich said.

Previous models for human origins suggested that present-day southern African hunter-gatherers, who split from other populations about 250,000-200,000 years ago, represent the deepest known branch of modern human variation. However, Lipson said, "the new analysis suggests that the lineage contributing to central African hunter-gatherers is similarly ancient and diverged from other African populations around the same time."

This finding adds to a growing consensus among archaeologists and geneticists that human origins in Africa may have involved deeply divergent, geographically separated populations.

Analysis also revealed another set of four human lineages branching between 80,000 and 60,000 years ago, including the lineages contributing most the ancestry in present-day eastern and western Africans and all non-Africans.

Considering this new model of human population relationships, the authors could show that about one third of the ancestry of the Shum Laka children derived from a lineage closely related to central African hunter-gatherers, and about two thirds of their ancestry came from a distinctive lineage distantly related to a majority of present-day West Africans.

"These results highlight how the human landscape in Africa just a few thousand years ago was profoundly different from what it is today, and emphasize the power of ancient DNA to lift the veil over the human past that has been cast by recent population movements," Reich said.

International collaboration

The international research team plans to return to Shum Laka this year, in part to help communicate findings to the Cameroonian academic and broader communities. "Interdisciplinary collaborations like this one are an essential part of ancient DNA research," says Reich.

Key Take-Aways

The study examines DNA from four people buried in the Shum Laka rockshelter in Cameroon, about 8,000 years ago and 3,000 years ago, at the transition from the Stone to Iron Ages. This study reports the first ancient DNA recovered from West or Central Africa, and includes some of the oldest DNA recovered from the African tropics.

This part of west-central Africa - the 'Grassfields' region of Cameroon - has been identified as the probable cradle of Bantu languages, the most widespread and diverse group of languages in Africa today. For decades, linguists, archaeologists, and geneticists have investigated the origin of Bantu languages and their spread.

None of the sampled individuals from Shum Laka are closely related to most present-day Bantu-speakers. Instead, they were part of a separate population that lived in the region for at least five millennia, and was later almost completely replaced by very different populations whose descendants comprise most people living in Cameroon today.

The Shum Laka individuals harbored about two-thirds of their ancestry from a previously unknown lineage distantly related to present-day West Africans and about one-third of their ancestry from a lineage related to present-day central African hunter-gatherers. This finding reveals previously unknown genetic diversity prior to the spread of food production.

Analysis of whole-genome ancient DNA data from these individuals provided insights into the relationships among several early-branching African human lineages. Results suggest that lineages leading to today's central African hunter-gatherers, southern African hunter-gatherers, and all other modern humans diverged in close succession about 250,000-200,000 years ago.

Another set of genetic divergences was identified dating to about 80,000-60,000 years ago, including the lineage leading to all present-day non-Africans.

These findings strengthen arguments recently made by archaeologists and geneticists that human origins in Africa may have involved deeply divergent, geographically separated populations.

Australian research collaboration makes first detection of 'ghost particles' from Bose-Einstein condensates made of light and matter.

The ANU/Monash University collaboration study:

Observed 'quantum depletion' for the first time in a non-equilibrium condensate

Discovered that 'light-like' condensates don't behave as we would expect

Observed 'ghost' excitations arising from quantum depletion for the first time.

QUANTUM DEPLETION OBSERVED FOR THE FIRST TIME

Bose-condensed quantum fluids are not forever.

Such states include superfluids and Bose-Einstein condensates (BECs).

There is a beautiful purity in such exotic states, in which every particle is in the same quantum state, allowing quantum effects to be seen at a macroscopic level visible on a simple microscope.

In reality though, not all particles stay in the condensate even at absolute zero where, classically, particles are expected to stand still. Instead, interaction-induced quantum fluctuations make the particles collide, unavoidably expelling some particles out of the condensate, a phenomenon called "quantum depletion".

This effect is incredibly strong in superfluid helium-4, the first known superfluid, such that 90% of the particles are expelled out of the condensate. However, in extremely dilute, ultracold atomic gases, which form the typical Bose-Einstein condensates (BEC) we know, the effect is much weaker, almost negligible.

Although quantum depletion has been well described theoretically (by the 70-year-old theory developed by Nikolay Bogoliubov), it has historically known to be difficult to measure in an atomic BEC for a number of reasons.

Instead of atomic particles, physicists at the Australian National University (ANU) use exciton-polaritons, hybrid particles with both light and matter character, which allows detection of momentum without any distortion.

The ANU team, led by Prof Elena Ostrovskaya, successfully detected the expelled particles by blocking the light, using a razor edge, emitted by the incredibly bright condensate. "It is like recreating a solar eclipse," says the study's lead author Dr Maciej Pieczarka. "The moon blocks the bright sun (the condensate) and exposes its glorious corona (the excitations)."

The study represents the first direct observation of quantum depletion in a non-equilibrium Bose-Einstein condensate (BEC).

'LIGHT-LIKE' CONDENSATES DON'T BEHAVE AS WE WOULD EXPECT. IN FACT, THERE IS NO EXPLANATION FOR THIS BEHAVIOUR

A surprising result of the study offers a new challenge for the physics of nonequilibrium quantum fluids. Exciton-polariton condensates can be tuned from more matter-like (excitonic) to more light-like (photonic), allowing for comparison with theories of equilibrium atomic (matter) condensate and of nonequilibrium quantum fluids of light.

(Exciton polaritons are a hybrid particle composed of a photon (light) and an exciton (a bound electron-hole pair))

The researchers found that when condensates were 'matter-like', they behaved precisely as expected for a BEC in thermal equilibrium (described by the long-standing Bogoliubov theory).

However, condensates that were 'light like' deviated from expected Bogoliubov behaviour, in a manner not described by any existing theories

In short, even if these condensates are driven-dissipative, they can behave like atomic condensates in equilibrium (when they are matter-like) or a non-equilibrium quantum fluid (when they are light-like).

NEGATIVE EXCITATION OBSERVED

The research resolves a long-standing problem in exciton-polariton condensates: the problem of visibility of excitation branches.

Quantum depletion leads to visibility of 'ghost' branches in the spectrum of excitations. Previously, only the positive or normal excitations had ever been observed in a spontaneously created, steady-state BEC, while the negative or ghost excitations predicted by Bogoliubov eluded observations in this regime.

Now, the ANU team used the interaction-dominated high-density condensates, in the steady-state regime, to increases the very weak signal from the ghost particles. This study demonstrates the first clear experimental observation of this ghost branch of elementary excitations in a spontaneously created, steady-state exciton-polariton condensate.

Unlike its normal counterpart, the ghost particles can only be created by quantum fluctuations and their detection in this study is the smoking gun of the quantum depletion of exciton-polariton condensates.

"The ironic thing about these expelled particles is that even though they are strictly not part of the condensate, they actually tell you almost everything about the depleted condensate," says co-author Dr Eliezer Estrecho.

The ANU-led team used the observation of the ghost branch to accurately measure the strength of interactions of exciton-polaritons, a key parameter that had a controversially large uncertainty based on other groups' measurements. The result is in full agreement with previous work by the ANU team, where the high-density, interaction-dominated condensate was serendipitously combined with the hole burning effect. Excellent agreement with theory has finally settled the controversy.

SUPERFLUIDS AND QUANTUM CONDENSATES

Superfluids, such as Helium-4, are closely related to Bose-Einstein condensates (BEC) of interacting bosons.

'Quantum depletion' describes the process by which, even at Absolute Zero, some of the particles that occupy the macroscopic quantum state become excited into higher momentum states via interparticle interactions and quantum fluctuations.

Essentially, such particles are 'expelled' out of the condensate.

Quantum depletion is particularly difficult to measure in non-equilibrium systems such as exciton-polariton condensates (photons coupled to electron-hole pairs in a semiconductor) since there are other processes that can produce the same expelling effect

In the new study, quantum depletion of an optically- trapped high-density exciton-polariton condensate is observed by directly detecting the process's telltale signature of the ghost particles occupying the negative branch of elementary excitations.

"The results call for a deeper understanding of the relationship between equilibrium and nonequilibrium BECs," says Prof Elena Ostrovskaya.

The team, which includes theory collaborators within the Monash University node of FLEET, is now extending their work to elucidate deeper underlying properties, like the phases and universal relations, of this light-matter hybrid of a condensate.

Among the Marvel characters, Spider-man has been the most popular character for the longest time of its history. The most attractive superpower of the Spider-man is that he shoots sticky spider webs to cling to walls or fly between buildings. Would his spider web be powerful in underwater, too? The answer is no. Because spider webs are dissolved in water and show no longer strong adhesion. However, mussels are capable of strong underwater adhesion. It is not even affected by heavy waves or storms. When a mussel is removed from a rock by force, surface of rock is also teared. That's how strong its adhesion is. Mussels produce tough fibers called byssus to attach to surface of a rock and, adhesive proteins are secreted when mussels make byssus.

Hyung Joon Cha, professor of POSTECH Chemical Engineering Department and his research team of Jeong Woo Han (Prof.) and Mincheol Shin collaborated with Nak-kyoon Kim of Korea Institute of Science and Technology on studying adhesive proteins in a mussel. They analyzed adhesive proteins secreted by mussels and confirmed two molecules, Dopa and Lysine which have strong adhesion even in underwater. Also, they discovered that these molecules have synergetic effect on mussel adhesions in various conditions. Their findings took one step closer in unveiling the secret of underwater mussel adhesion.

Before their findings, researchers paid attention to a molecule, Dopa. The shape of Dopa has been imitated to make underwater adhesives. But, there has been a limitation in making underwater adhesives as strong as nature adhesives of mussels because it has been challenging to balance between surface adhesion, which is attraction between surface and adhesives, and cohesion of adhesive molecules.

Unlike the conventional studies, the research group of Cha recognized an important role of another molecule called Lysine in underwater mussel adhesion. The interfacial adhesive protein, fp-3F, is located in surface of mussels and contains a great quantity of Dopa, which makes underwater adhesion possible and Lysine, which has a positive electric charge. The joint research team observed distribution of these molecules in the protein and found an interesting fact that these molecules were either bound to or apart from each other at a specific location.

Based on the sequencing of an interfacial adhesive protein, they synthesized three simple peptides with each different distance between Dopa and Lysine. By testing these model peptides, they discovered that the distance between Dopa and Lysine affected their synergy on surface adhesion and cohesion differently.

First of all, when these two molecules were adjacent to each other, surface adhesion of the peptide increased greatly. The team confirmed that Lysine enhanced underwater surface adhesion by attracting water molecules, which disrupted underwater adhesion, in the surface and water molecules around Dopa.

Next, they noticed that ferric ion(Fe3+)-mediated cohesion diminished unlike the surface adhesion when Lysine was flanked to Dopa. They explained that this was because Lysine disrupted ferric ion, a mediator for cohesion, from approaching Dopa electrically and structurally.

Through molecular biology techniques, they synthesized two different proteins with artificial sequences and compared with proteins with natural sequence to apply the same mechanism in interfacial adhesive proteins of a mussel. As a result, they verified that the identical result was obtained in the proteins with artificial sequences.

Professor Cha said, "We discovered synergy of two molecules, Dopa and Lysine which are known to play important roles in underwater adhesion. With this accomplishment, we anticipate to see new underwater bioadhesives on another level." Also, this research explained how adhesive proteins of a mussel are designed and could enlighten future studies of other adhesive proteins in nature.

Their research accomplishment has been recently posted in Journal of Colloid and Interface Science, the world's prominent journal in the field of interface science. The research was supported by the Basic Science Research Program through the National Research Foundation of Korea.

SAN FRANCISCO (January 21, 2020)--From sea shores to salt flats, a high incidence of spiders spin a life in or around water. Researchers at the California Academy of Sciences and William Paterson University found that nearly one fifth of all spider families are associated with saltwater or freshwater aquatic habitats. Their findings--recently published in the Zoological Journal of the Linnean Society and aptly titled "The Life Aquatic with Spiders"--address the common misconception that all spiders dwell on land, and reveal surprising evolutionary pathways of this group from a land-based existence back to a water-based existence.

"This study shines a light on what was previously a dark corner of the spider tree of life," says senior author Lauren Esposito, PhD, the Academy's Curator of Arachnology. "It's the most extensive literature review of aquatic spiders to date--we were blown away by the extent that spiders have evolved to interact with aquatic habitat."

Illuminating "The Life Aquatic with Spiders"

To catalogue these water-dwelling spiders, the team first consulted years of prior research led by Academy colleagues. A spider group known as Dictynidae caught their attention: Although known to contain remarkable diversity of aquatic spiders from around the globe, the group presented tangled species relationships. Using DNA analysis, the team carefully studied and sorted specimens, flagging instances where a species evolved a full or partial association with water. Of 120 spider families across the tree of life, they found that members of 21 families exhibited an affinity for aquatic habitat. This group represents nearly one fifth of all spider families known to science.

"We're grateful for the collaborative spirit of our colleagues, whose prior research laid the groundwork for our team," says lead author Sarah Crews, PhD and an Academy researcher. "Not only were we fascinated by the Dictynidae group's unique ecology and remarkable diversity, we also realized no one has ever given them a closer look."

While some aquatic spider species share a common ancestor, the co-authors concluded that most are distant cousins with superficially similar traits--a phenomenon known as convergent evolution. Knowing the group lacked a single evolutionary origin, the study team set out to compile an "atlas of characteristics" to see if certain traits give spiders a leg up (or eight) when thriving in harsh, watery worlds.

Armed with aquatic adaptations

Aquatic spiders display a vast and specialized array of adaptations, suggesting they lead more water-inclined lives than previously thought.

Consider the Maningrida diving tarantulas of Australia's Northern Territory, which sport dense hairs that repel water and keep (all four of) their lungs dry. When heavy rains arrive, the spiders retreat into waterproof burrows--if flooded, they can hunker down in an armor of air bubbles and withstand up to six hours of full submersion. In freshwater habitats across the globe, fishing spiders utilize the water's surface as an extension of their sensory system: Each ripple alerts of an approaching fishy meal. And in hot, parched pockets of the evaporated Salton Sea, the salt flat spider thrives in the freshwater that pools between gaping cracks and saline crusts. The only truly aquatic spider--the diving bell spider of Europe and Asia--spins a submerged silken web that it inflates like a balloon by dragging air bubbles down from the surface.

"We found that many adaptations are widespread across water-dwelling spider species, while other water-dwelling spiders lack these favorable characteristics entirely," says Esposito. "We were surprised to find that these traits--although certainly helpful--are not a prerequisite to being able to withstand a life submerged in water."

Evolutionary pathways less traveled

The ancestors of spiders--and all terrestrial life--originated in the ocean.

"We know that spiders have aquatic origins," says Crews. "So in some ways, it comes as no surprise that they are predisposed to coping with full or partial submersion in water."

What's puzzling is the evolutionary steps that Dictynidae spiders took to arrive back at their aquatic lifestyle.

"They didn't follow the evolutionary steps we expected them to," says Esposito. "Every time we identified a saltwater spider species, its closest relative was living on land, rather than around freshwater. This tells us that perhaps spiders are pre-adapted to live in various types of water habitat, and don't need to take evolutionary baby steps from land to freshwater to saltwater."

Esposito and Crews hope that future data collection will allow for a finer-scale analysis of how these spiders have evolved to navigate watery worlds.

"It's been hypothesized that aquatic spiders have beneficial adaptations, like producing more silk or being better at regulating water for salt tolerance," says Esposito. "With a deeper understanding of these broad evolutionary patterns, we hope to tease apart certain physiological characteristics and physical traits important for living in aquatic environments. These findings could have implications for technologies ranging from biomaterials derived from silk to agricultural crops designed with higher salinity tolerances."

For now, the team will continue to explore and surface the life aquatic of spiders--one surprising find at a time.

Often, patients from the same family and carriers of the same genetic mutation, develop a disease differently. This disparity may be due to the existence of mutations in other secondary genes, which influence the onset and progression of the disease caused by the main mutation. As an example, members of a family who are carriers of the same mutation may show symptoms of the disease at age 20, and others at age 50. Knowing what factors influence the onset and development of the disease would help a better prognosis and the application of preventive treatments. Retinitis pigmentaria is a group of a genetic and degenerative diseases characterized by the loss of light-receptor cells in the retina, this causes a non-responder retina and a progressive vision loss.

Two researchers from Dr. Cerón's group, Dmytro Kukhtar and Karinna Rubio-Peña, from Bellvitge Biomedical Research Institute (IDIBELL), have worked on this topic in the last few years. To do it, and by CRISPR gene-editing technology, they introduced in C. elegans worms, mutations that cause retinitis pigmentaria in humans. Next, these mutations were classified into two groups: those that caused an obvious problem to worms (eg sterility or smaller size) and those that did not.

Worms that were not affected by human mutations were used to search for other genes whose inactivation caused alterations in the mutant worms, but not in the control worms. Thus, up to three genes were identified as candidates to be disease modifiers, and in cooperation with the main mutation could be affecting disease progression.

On the other hand, those avatar worms to which the human mutation caused them a defect were used to look for drugs that would alleviate the negative effect of the mutation. The result was surprising because researchers identified drugs that were harmful to worms harboring patient mutations, but these drugs did not affect control worms equally. In this way, this study changes the paradigm of drug screens since although it is important to find drugs that cure, it is also relevant for health to identify those drugs that could be harmful to patients with certain genetic mutations.

After years of research on cell surface receptors called Frizzleds, researchers at Karolinska Institutet in Sweden provide the proof-of-principle that these receptors are druggable by small molecules. The results, which are published in the scientific journal Nature Communications, open for new strategies to treat different types of cancer.

For more than 20 years Frizzleds (FZDs) have been proposed as suitable therapeutic targets for the treatment of diverse forms of cancer and several other disorders, such as fibrosis and cardiovascular disorders. They belong to the family of G protein-coupled receptors, which are involved in the progress of many diseases and are very common targets for drugs.

Large efforts have been undertaken to attack FZDs using therapeutic antibodies and other biopharmaceuticals. It has not previously been possible to design small molecules that would target FZDs pharmacologically. The Schulte laboratory at the Department of Physiology and Pharmacology, Karolinska Institutet, has now repurposed an existing small-molecule drug targeting a related receptor and shown that it can bind to and activate FZDs.

"Our study provides proof-of-principle that it is possible to target FZDs with small molecules," says Professor Gunnar Schulte, who led the study. "This is a breakthrough laying the basis for development of novel and improved compounds that target FZDs for the treatment of different types of cancer."

Key to the discovery was on the one hand a basic understanding of FZDs as pharmacological receptors and on the other hand a technical advance in drug screening.

"However, the most important driving force was a clever, translational idea by postdoctoral fellow Pawel Kozielewicz in my lab, who identified the first small molecule that activates a Frizzled receptor," says Gunnar Schulte. "Furthermore, computer simulations performed by postdoctoral fellow Ainoleena Turku allowed validation of laboratory experiments presenting deep structural insight into receptor-drug interactions."

Researchers at Chalmers University of Technology and Gothenburg University in Sweden have achieved something long thought almost impossible - counting the molecules of the neurotransmitter glutamate released when a signal is transferred between two brain cells. With a new analysis method, they showed that the brain regulates its signals using glutamate in more ways than previously realised.

The ability to measure the activity and quantity of glutamate in brain cells has been long sought-after among researchers. Glutamate is the major excitatory neurotransmitter in the brain. Despite its abundance, and its influence on many important functions, we know a lot less about it than other neurotransmitters such as serotonin and dopamine, because so far glutamate has been difficult to measure quickly enough.

The new findings around glutamate are therefore very significant and could help improve our understanding of the pathologies underlying neurological and psychiatric diseases and conditions. The relationship between glutamate and these disorders, as well as our memory, our appetite and more, are just some of the questions which the researchers' newly discovered technology could help answer.

"When we started, everybody said 'this will never work'. But we didn't give in. Now we have a beautiful example of how multi-disciplinary basic science can yield major breakthroughs, and deliver real benefit," says Ann-Sofie Cans, Associate Professor in Chemistry at Chalmers and leader of the research group.

The key was to do the opposite of what had been previously attempted. Instead of using a biosensor made from thick layers, they used an ultrathin layer of the enzyme needed for biological identification. The researchers made it so that the enzyme, which was placed on a nano-structured sensor surface, was just a molecule thick. This made the sensor technology a thousand times faster than previous attempts.

The technique was therefore fast enough to measure the release of glutamate from a single synaptic vesicle - the small liquid vessel which releases neurotransmitters to the synapse between two nerve cells. This is a process that occurs in less than a thousandth of a second.

"When we saw the benefits of improving the sensor technology in terms of time, instead of concentration, then we got it to work" says Ann-Sofie Cans.

The research was carried out in two steps. In the first, the breakthrough was being able to measure glutamate. That study was published early in Spring 2019 in the scientific journal ASC Chemical Neuroscience. In the second part, which the current publication addresses, Ann-Sofie Cans and her research group made further important adjustments and ground-breaking discoveries.

"Once we had built the sensor, we could then refine it further. Now, with the help of this technology we have also developed a new method to quantify these small amounts of glutamate," she explains.

Along the way the group had many interesting surprises. For example, the quantity of glutamate in a synaptic vesicle has been revealed to be much greater than previously believed. It is comparable in quantity to serotonin and dopamine, a finding which came as an exciting surprise.

"Our study changes the current understanding of glutamate. For example, it seems that transport and storage of glutamate in synaptic vesicles is not as different as we thought, when compared with other neurotransmitters like serotonin and dopamine", says Ann-Sofie Cans.

The researchers also showed that nerve cells control the strength of their chemical signals by regulating the quantity of glutamate released from single synaptic vesicles.

The fact that researchers can now measure and quantify this neurotransmitter can yield new tools for pharmacological studies in many vital areas in neuroscience.

"The level of measurement offered by this ultra-fast glutamate sensor opens up countless possibilities to truly understand the function of glutamate in health and disease. Our knowledge of the brain function, and dysfunction, is limited by the experimental tools we have, and this new ultra-fast tool will allow us to examine neuronal communication at a level we did not have access to before", says Karolina Patrycja Skibicka, Associate Professor in Neuroscience and Physiology at Gothenburg University.

"The new finding, that glutamate-based communication is regulated by the quantity of glutamate released from synaptic vesicles, begs the question of what happens to this regulation in brain diseases thought to be linked to glutamate, for example epilepsy."

ROCHESTER, Minn. -- Mesenchymal stromal cells from fat tissue and bone marrow are widely used in therapeutic trials for their anti-inflammatory qualities, but new Mayo Clinic research finds that liver cells may be of greater value.

The study, published in Liver Transplantation, finds that liver mesenchymal stromal cells have immunoregulatory qualities that make them more effective than similar cells derived from adipose, or fat, tissue and bone marrow.

"This is very exciting, given that many ongoing trials around the world use mesenchymal stromal cells from bone marrow or fat tissue," says Timucin Taner, M.D., Ph.D., a Mayo Clinic transplant surgeon, and the study's principal investigator and first author. "If our findings are validated, liver mesenchymal stromal cells would be a much better option for those kinds of therapeutic applications."

The cells could be valuable in treating a wide range of diseases and conditions with underlying inflammation, such as organ rejection after transplantation, inflammatory bowel disease and other autoimmune disorders.

The liver is an immunologically active organ, and liver transplant recipients require much lower doses of anti-rejection medications than patients receiving other organs. "We have been interested in this phenomenon for a while, and have been studying the mechanisms of the liver's tolerance-inducing properties in transplant recipients," Dr. Taner says. "In this research, we found that liver mesenchymal stromal cells were much more potent than their counterparts from other tissues in their ability to control immune responses, which may explain why liver transplants are better tolerated."

It also may explain why the incidence of kidney rejection in patients who undergo a kidney-liver transplant is significantly lower than those of kidney-only transplant recipients. Similar results have been noted in other multiorgan transplants involving the liver, such as combined heart-liver transplants.

Mesenchymal stromal cells, which are found in most liver tissues, have a capacity to regulate inflammation and tissue repair mechanisms. For this study, liver mesenchymal stromal cells were generated in vitro from 12 biopsy specimens from people of various ages and both genders.

In each phase of experimentation, the liver mesenchymal stromal cells appeared superior to those from bone marrow and adipose tissue, regardless of the age or sex of the donor. Further research in humans will be needed to test the anti-inflammatory superiority of the cells, Dr. Taner says.

"We now need to go deeper and try to understand why and how liver mesenchymal stromal cells are different from mesenchymal stromal cells from other tissues," he says.

La Jolla, California (January 18, 2020). A new study published in the Journal of Clinical Investigation enrolled people with HIV who also happened to have a terminal illness to study where HIV hides in the human body so doctors can better treat and maybe even cure HIV.

Selfless Terminally Ill Persons Join Doctors To Study HIV

Despite understanding that HIV exists throughout the human body, researchers working toward a cure of HIV do not understand how HIV populates deep tissues. "Unfortunately, we simply cannot know the answer until a person is deceased and subject to an autopsy. Delays between death and when tissues are collected means the virus degrades, obscuring where HIV really hides," said Davey Smith, MD, the senior author and Chief of Infectious Diseases and Global Public Health at UC San Diego.

To fill this gap, the team turned to terminally ill persons who happened to have HIV, and with their consent, the team serially collected blood while the person was alive, and then performed a rapid autopsy at the time of their death. "This donation at the end of one's life is the first of its kind in HIV research, and allowed us to discover all the places HIV hides, even during treatment where the virus is difficult to detect in standard blood tests."

Terminally ill volunteers were eager to support this groundbreaking work. "Our participants have HIV but are dying of something else, like cancer. They are going through a lot, but they still want to leave a larger legacy behind and help find a cure for HIV," said Sara Gianella, MD, assistant professor at UC San Diego Health and study coauthor. Study participants were either self-referred from hearing about the study or referred from their primary HIV providers. "Only one potential volunteer decided ultimately not to participate," added Dr. Gianella."It is an amazing gift from both the participants and their families."

Where does HIV hide?

Study investigators found HIV in every one of the 30 organ sites they studied, even when the deceased participant was taking modern HIV therapy . When the virus was sequenced, some of the virus had genetic defects, which meant that it was nonfunctional or likely 'dead', but most of the virus seemed to be intact and able to grow.

"As expected, most of the HIV was in the blood, gut and lymph nodes," said Antoine Chaillon, MD, PhD, assistant professor in the Division of Infectious Diseases and Global Public Health at UC San Diego and the study's lead author. "But, intact HIV was also found in the brain, liver, spleen, kidney, basically everywhere."

It seems that having HIV in all these tissues can cause problems, even when someone is taking HIV therapy, and active HIV growth is 'undetectable' in blood. Being 'undetectable' in blood means that a person's HIV therapy has basically stopped the growth of HIV in the blood. Although antiretroviral therapy can keep HIV from replicating, it does not stop all of the problems associated with HIV. Persons with HIV have more inflammation-related diseases, like heart attacks, stroke and cancer, than people who do not have HIV. "We do not fully know why," Dr. Gianella said. "We think that when HIV tries to regrow in each of these tissues where it was lying dormant, it can cause an inflammatory response. Even though the antiretroviral therapy keeps it from fully replicating, it still causes local damage."

"Yes," Dr. Smith added. "For example, half of persons with HIV have neurocognitive impairment even when taking the very best HIV therapy. How HIV causes local inflammation in the brain, even during therapy, may explain this."

"Further improving the health of people with HIV likely means we need to figure out how to clear HIV from its hiding places," Dr. Chaillon said. "This means new therapies."

How HIV moves in the body?

Two of the study's participants had stopped taking their HIV therapy, leading to even more new insights. "Sometimes when people have a terminal illness they don't want to keep taking their medicines anymore," Dr. Gianella explained. "This gave us a unique opportunity to study how the virus replicated and moved in the body while the virus was untreated. We collected the participant's blood before and after stopping their therapy, while they were alive, and then we collected all the tissues after they died. Since HIV evolves quickly within a person, we were able to identify the same viruses that restarted replicating in the blood after the person stopped their therapy in all their tissues after death."

"We expected the replicating virus to seed blood cells and cells in the gut and lymph nodes," added Dr. Chaillon, "but we were surprised at how quickly the virus was everywhere!" The team used new analytical methods, to find that the virus moved between tissues in the body. Cells in the blood and the gut seemed to be the source of most HIV in the rest of the body, and most HIV was trafficked through the body by the blood.

What does this mean for curing HIV?

Developing a way to keep HIV from replicating when therapy is stopped, often called 'therapy free remission', is a major goal for HIV researchers. Two people seem to have achieved this goal through treatments with special bone marrow transplants. "But even in these patients they still have intact virus throughout their body, even if it cannot get to the bloodstream," said Dr. Smith. "Our study found that HIV was mainly trafficked through the body in the blood. This might explain why we saw therapy-free remission in the two persons with bone marrow transplants," Dr. Smith explained. "After the transplants, their blood cells were protected and could no longer carry HIV. They still have intact virus throughout their body, but it can't get to the bloodstream to start replicating."

"But, HIV in these tissues still likely cause local inflammation and damage," Dr. Chaillon added. "We need new ways to clear those places and extensions of our work can some day answer how."

"When looking at the status of planet Earth and the influence of current global agriculture practices upon it, there's a lot of reason to worry, but also reason for hope - if we see decisive actions very soon," Dieter Gerten says, lead author from PIK and professor at Humboldt University of Berlin. "Currently, almost half of global food production relies on crossing Earth's environmental boundaries. We appropriate too much land for crops and livestock, fertilize too heavily and irrigate too extensively. To solve this issue in the face of a still growing world population, we collectively need to rethink how to produce food. Excitingly, our research shows that such transformations will make it possible to provide enough food for up to 10 billion people."

The researchers ask the question how many people could be fed while keeping a strict standard of environmental sustainability worldwide. These environmental capacities are defined in terms of a set of planetary boundaries - scientifically defined targets of maximum allowed human interference with processes that regulate the state of the planet. The present study accounts for four of nine boundaries most relevant for agriculture: Biosphere integrity (keeping biodiversity and ecosystems intact), land-system change, freshwater use, and nitrogen flows. Based on a sophisticated simulation model, the impacts of food on these boundaries are scrutinised at a level of spatial and process detail never accomplished before, and moreover aggregated to the entire planet. This analysis demonstrates where and how many boundaries are being violated by current food production and in which ways this development could be reverted through adopting more sustainable forms of agriculture.

Globally differentiated picture: In some regions, less would be more

The encouraging result is that, in theory, 10 billion people can be fed without compromising the Earth system. This leads to very interesting conclusions, as Johan Rockström, director of PIK points out: "We find that currently, agriculture in many regions is using too much water, land, or fertilizer. Production in these regions thus needs to be brought into line with environmental sustainability. Yet, there are huge opportunities to sustainably increase agricultural production in these and other regions. This goes for large parts of Sub-Saharan Africa, for example, where more efficient water and nutrient management could strongly improve yields."

As a positive side effect, sustainable agriculture can increase overall climate resilience while also limiting global warming. In other places, however, farming is so far off local and Earth's boundaries that even more sustainable systems could not completely balance the pressure on the environment, such as in parts of the Middle East, Indonesia, and to some extent in Central Europe. Even after recalibrating agricultural production, international trade will remain a key element of a sustainably fed world.

Hard to chew: Dietary changes needed

Importantly, there is the consumers' end, too. Large-scale dietary shifts seem to be inevitable for turning the tide to a sustainable food system. For example, regarding China's currently rising meat consumption, parts of animal proteins would need to be substituted by more legumes and other vegetables. "Changes like this might seem hard to chew at first. But in the long run, dietary changes towards a more sustainable mix on your plate will not only benefit the planet, but also people's health", adds Vera Heck from PIK. Another crucial factor is reducing food loss. In line with scenarios adopted in the present study, the most recent IPCC Special Report on land use found that currently, up to 30 percent of all food produced is lost to waste. "This situation clearly calls for resolute policy measures to set incentives right on both the producers' and consumers' ends", Heck further lays out.

Perhaps the most sensitive and challenging implication of the study relates to land. "Anything involving land tends to be complex and contested in practice because people's livelihoods and outlook depend on it. Transitioning to more sustainable land use and management is therefore a demanding challenge to policy-making. Key to success is that the regions affected need to see clear benefits for their development. Then there is a real chance that support for new directions will grow fast enough for stabilising the Earth system", says Wolfgang Lucht, co-chair for Earth System Analysis at PIK and co-author of the study.

A study involving researchers from King's College London, has developed a predictive tool that can recognise adolescents who are at high or low risk of depression in young adulthood.

Using data from over 2,000 Brazilian adolescents, the researchers developed the tool that can help identify which young people will go on to experience a major depressive disorder when they reach 18 years.

Published in the Journal of the American Academy of Child and Adolescent Psychiatry, the study also evaluated the performance of the tool in samples of adolescents from New Zealand and the UK, demonstrating differences in its ability to predict depression across these countries and highlighting the need to consider local variations when developing predictive tools.

The research is part of the Identifying Depression Early in Adolescence (IDEA) project funded by mental health research charity MQ. King's College London is the lead institution on the IDEA project.

Valeria Mondelli, IDEA project lead and author on the study, from the Institute of Psychiatry, Psychology & Neuroscience (IoPPN) King's College London said : 'This research marks an important first step in developing an accessible tool that could help screen adolescents for depression and improve mental health worldwide. Depression can have debilitating lifelong impacts and adolescents are especially vulnerable to its onset. Identification of those at high risk of developing depression in later adolescence could be valuable in devising effective early-intervention strategies to help prevent this illness.'

Predictive tools have already been developed for psychosis and many physical health conditions, but little has been done for depression, despite its prevalence. Current methods for assessing the risk of depression are based on family history and subthreshold symptoms which do not reach the criteria for depression.

Based on existing research and clinical expertise the researchers identified 11 sociodemographic variables that could be combined into a single score to recognise those adolescents at risk of developing depression. In addition to a strong association with depression the variables were chosen because they were also easy to collect and simple to evaluate (see notes to editors for a list of variables).

Christian Kieling, lead author on the study from Universidade Federal do Rio Grande do Sul, Brazil said: 'In our study we tried to go beyond more traditional ways of identifying youths at high risk of depression and learn from other medical specialties that combine multiple variables to generate composite risk scores, such as the Framingham cardiovascular risk score. This is relatively new in the field of mental health.'

Using data on these 11 variables from 2,192 Brazilian 15-year-old adolescents and mental health assessments of the same adolescents at 18 years old, the researchers developed the tool to assess the risk of development of a major depressive disorder.

The study compared the ability of this tool to predict depression in a sample of 1,144 British 12 year olds (no data was available at age of 15) from the E-Risk Study and 739 New Zealand 15 year olds from the Dunedin study.

The predictive ability of the score was not as strong in the UK and New Zealand samples. According to researchers this was to some extent expected as not all the information used from the Brazilian sample was available in the other datasets and different diagnostic measures were used to assess mental health at 18 years old.

Dr Kieling said: 'The existence of these discrepancies does not discount the value of our tool but provides important insight into adapting the score according to where it will be used. Adaptation is necessary for most predictive tools; for instance, tools used to assess the risk of cardiovascular disease developed in the US require adjustments when used in other countries. As part of the IDEA project, we are also working to further improve the precision of the tool by studying biomarkers of risk for depression in adolescents.'

Dr Mondelli added: 'When developing any new risk assessment tool it is important to consider how it will work in the real world. As part of the IDEA project we are interviewing adolescents, parents and other stakeholders to understand their perceptions of this tool and the ethical implications of using it to stratify young people in terms of risk for developing depression. By doing this we hope that we can ensure that it can help improve the mental health of adolescents worldwide.'

Scientists say a type of algae crucial to the survival of coral reefs may be able to resist the impacts of ocean acidification caused by climate change.

In a world-first, the team--including researchers from the ARC Centre of Excellence for Coral Reef Studies at The University of Western Australia (Coral CoE at UWA)--found that coralline algae are able to build tolerance to ocean acidification over multiple generations.

"Coralline algae go through a natural process of calcification, where they build a crustose-like calcium carbonate skeleton," said lead author Dr Christopher Cornwall.

"Skeletons like this provide structure, allowing them to grow, as well as providing a substrate for other organisms such as corals to grow upon," he said.

"We show, for the first time, that while growth of these skeletons is initially susceptible to the effects of ocean acidification caused by increased CO2, over multiple generations they develop resistance."

Coralline algae are vital not only to the survival of coral reefs but many ocean species.

"Crustose coralline algae bind coral reefs together," said Professor McCulloch, Coral CoE Deputy Director, who led the research group. "Without it, coral reefs as we know them today wouldn't exist," he said.

"These species limit erosion in reefs that are often made up of mainly coral fragments, act as a nursery for many marine species, and are the main player in temperate reef formation along the Australian and New Zealand coastlines."

The experiments took more than 18 months to complete. On average, the algae took six generations of about six to eight weeks each to develop resistance to ocean acidification.

The findings of the study are important in understanding how longer-lived species, such as tropical corals, could respond over multiple generations to ocean acidification.

"Coralline algae are a useful model species to test hypotheses about adaptation or acclimation over time as they grow to maturity in six weeks as opposed to several years for many coral species," Dr Cornwall said.

The next step is to test a wider range of coralline algae species.

"This research focused on tropical coralline algae species from northern Australia, so the next step is to study temperate species--like those in southern Australian and New Zealand waters--that grow a lot slower and may not acclimatise to climate change as quickly."

Scientific and public appreciation for microbes--and the key role their communal actions play in environmental health, food production, and human wellness--has grown in recent years. While initially considered to be static, uniform entities, microbial communities are highly complex and contain internal chemical swapfests that are in constant flux.

Researchers at the University of Illinois at Urbana-Champaign led by Associate Professor of Bioengineering Ting Lu have demonstrated that the dynamics of these communities can be explained and even predicted by examining the variability trait of microbial social interactions. Lu and his coauthors, including co-first authors Feng Liu and Junwen Mao and Grainger Distinguished Chair in Engineering Rashid Bashir, shared their work in Nature Communications.

"The ultimate goal of our research is to develop effective strategies to program the composition and functionality of microbial communities," Lu said. This broader goal is shared by the Microbiome Metabolic Engineering research group at Illinois' Carl R. Woese Institute for Genomic Biology, of which Lu is a member. "But to achieve this kind of engineering capacity, there're several key steps. The first step is to understand how microbial communities change over time, the second is to predict the dynamics, and the third is to engineer it."

In the present study, Lu's group aimed to begin a transition between the first and second steps, from the perspective of microbial interactions such as competition and cooperation, major biotic driving forces of community behaviors.

"There is increasing evidence that microbial interactions are dynamic over time, instead of invariant," Lu said. "They often change with environmental cues, such as pH, nutrient and stress, and are also subjective to the population of microbes generating the interactions and the presence of other species."

"But there are little experimental investigations that are trying to elucidate how such variations contributes to community structures," Lu continued. "We hypothesize that this form of variation is an important determinate that regulates community dynamics and that characterizing it can empower the predictions of ecosystem succession from the bottom up."

To test the hypotheses, Lu and his colleagues wanted to utilize communities in which bacteria cooperate or compete in easily observable and controllable ways. They turned to synthetic communities of Lactococcus lactis, the bacterium that helps ferment milk into cheese, due to their reduced complexity compared to native ecologies.

One important way that microbes interact is through the exchange of the compounds they produce--nutrients, chemical signals, and even toxins that kill off competitors. Lu's team created two L. lactis strains, Cα and Cβ, each of which could produce one subunit of an antimicrobial peptide (small protein) called nisin.

"Each of the strains is able to produce an inactive subunit. However, when together, the two strains released subunits that self-assemble into active nisin," Lu said. Experiments confirmed that, when teamed up, the engineered Cα and Cβ could indeed cooperate to fight against Ks, another strain which produces its own toxin.

The team examined the outcomes of communities formed by Cα, Cβ and Ks, and found that increasing the variations of Cα--Cβ cooperation, from either altered labor partition or random sampling, drives the community into distinct structures. They also studied ecosystem succession in different environmental pH using Cα, Cβ and another strain, Kp, that is resistant to bacteriocin at certain levels of acidity. Their study showed that, when the cooperation and competition are additionally modulated by pH, ecosystem succession becomes jointly controlled by the variations of both interactions and yields more diversified dynamics--some communities changed dramatically over time, while other stayed more stable.

The researchers constructed mathematical models that explicitly incorporated the variability of interaction into ecosystem description.

"Asking for seamless integration of experiment and modeling was the most challenging part [of the study]. But it was also the most exciting part, because the model--which incorporated the variability from the experimental measures--allowed us to correctly predict the behavior [of the microbial communities,]" Lu said.

The team hopes that this work would serve as a foundational step toward the analysis, prediction, and engineering of complex communities such as those that we rely on for many human endeavors and our own health. "This study used simple, synthetic consortia," Lu said "We look forward to working on naturally occurring communities . . . hopefully by studying those native ecologies, we will be able to establish basic rules of community organization and even develop feasibility to engineer ecosystem functionality."

EAST LANSING, Mich. - Have I got a fish story for you. Any angler beginning a yarn like that usually ends up spinning a tall tale, an exaggeration or bald-faced lie.

Michigan State University researchers, however, have demonstrated that anglers can produce accurate and complex environmental models similar to those of trained scientists.

The study, led by graduate student Payam Aminpour and Steven Gray, community sustainability professor, shows that fisheries stakeholders can accurately predict pike populations, predator abundance, habitat and fishing pressure.

"This is a novel and potentially revolutionary way to estimate the status of the environment," Gray said.

The survey was conducted in Germany and involved more than 200 anglers, fishing clubs board members and others. They were asked to create drawings that represent ecological relationships influencing the pike population, including fishing pressures and nutrient availability. The individuals' models were then mathematically combined into a collective model representing the community's understanding of the ecosystem.

"The solution produced a model of ecological relationships that is similar to scientists' understanding of pike ecology," Aminpour said. "The accuracy of the results improves when more anglers are involved."

Aminpour found that it is important that the opinions of different types of anglers - recreational, fisheries managers and board members of fishing associations - are taken into account. If the knowledge of only one type of angler is considered, their biases lead to an inaccurate solution.

"Our study shows that it makes sense to involve as many different interest groups as possible, such as anglers, hunters, foresters and conservationists," Gray said. "If as many ideas as possible are involved, the result will be particularly good."

The foundational theory supporting the study is known as "the wisdom of crowds" or "collective intelligence."

Popularized by Francis Galton in 1907, the theory has been applied to many situations over the past century, from people estimating the number of jellybeans in a jar to predicting the winners of major sporting events - often with high rates of success.

Using the wisdom of crowds to better understand the environment is a new approach to managing natural resources. The researchers advocate for gathering the knowledge of local people to understand ecosystems where scientific information is limited.

"About 100 years after the introduction of the wisdom of crowds phenomenon, we have expanded this theory by demonstrating that the collective judgment of large crowds can have incredible scientific accuracy," Aminpour said. "We have shown that this phenomenon exists not only in simple estimation tasks but also in more complex tasks, like predicting the relationships that drive a fishery ecosystem."

The MSU Human-Environment Interactions Lab and their international team of collaborators are applying the principles of collective intelligence to address some of the most pressing environmental issues, such as warming oceans, the impact of climate change on coastal communities, wildfires, degraded wildlife ecosystems and other sustainability issues.

WASHINGTON (Jan. 21, 2020) -- Maternal depression in the postpartum period, and even beyond, is associated with the development of atopic dermatitis (AD) throughout childhood and adolescence, according to a recent study published in the journal Dermatitis.

AD is a chronic, inflammatory skin disease typically characterized by itch, pain, and sleep disturbance. It has also been strongly linked to a number of mental health disorders, such as depression, anxiety, and suicidal ideation.

The study, led by Jonathan Silverberg, MD, PhD, MPH, associate professor of dermatology at the George Washington University School of Medicine and Health Sciences, examined the association of maternal depression in the postpartum period, and maternal and paternal depression in later childhood with AD in U.S. children and adolescents.

Silverberg conducted the data acquisition, analysis, and interpretation at Northwestern University Feinberg School of Medicine, in collaboration with first author Costner McKenzie, a medical student at Northwestern.

"We know that emotional factors can exacerbate AD flares and influence the course of the disease," said Silverberg, the senior author of the study. "Previous studies have shown that family environment and other environmental factors can have an impact on AD."

The researchers analyzed data from the Fragile Families and Child Wellbeing Study. They found that postpartum depression was associated with higher odds of AD developing later in childhood, more persistent AD, and increased sleep disturbance among children with AD.

"Our results further suggest that postpartum depression is associated with AD even in older children and adolescents, with more persistent disease and greater sleep disturbance," Silverberg said. "This could potentially suggest more severe AD."

Continued research is needed, according to the researchers, to confirm the associations found, determine underlying mechanisms, and identify appropriate interventions. The authors of the study suggest that pediatricians should consider screening and early intervention for postpartum depression to identify infants at higher risk for AD.

Children born to mothers with depression in the postpartum period and beyond may warrant increased screening for AD and atopic disease, as well as use of gentle skin care and other strategies to mitigate AD.