The Art of Science

Moths and magnets could save lives

Rice University bioengineers use a magnetic field to activate nanoparticle-attached baculoviruses in a tissue. The viruses, which normally infect alfalfa looper moths, are modified to deliver gene-editing DNA code only to cells that are targeted with magnetic field-induced local transduction.

Stem cells organize themselves into pseudo-embryos

The definitive architecture of the mammalian body is established shortly after implantation of the embryo in the uterus. The antero-posterior, dorso-ventral and medio-lateral axes of the body become organized under the control of gene networks that coordinate the transcription of DNA in various regions of the embryo. 

Researchers now report the ability of mouse stem cells to produce pseudo-embryos that display similar capacities. Established from about 300 embryonic stem cells only, these structures, called gastruloids, show developmental features comparable to that of the posterior part of embryos aged from 6 to 10 days. The study, published in the journal Nature, shows that the three main embryonic axes are formed according to a gene expression program similar to that of embryos. Gastruloids thus possess a remarkable potential for the study of the early stages of normal or pathological embryonic development in mammals. 

Your gut is directly connected to your brain, by a newly discovered neuron circuit 

The human gut is lined with more than 100 million nerve cells—it’s practically a brain unto itself. And indeed, the gut actually talks to the brain, releasing hormones into the bloodstream that, over the course of about 10 minutes, tell us how hungry it is, or that we shouldn’t have eaten an entire pizza. But a new study reveals the gut has a much more direct connection to the brain through a neural circuit that allows it to transmit signals in mere seconds. The findings could lead to new treatments for obesity, eating disorders, and even depression and autism—all of which have been linked to a malfunctioning gut.

Scientists grow human esophagus in lab

The newly published research is the first time scientists have been able to grow human esophageal tissue entirely from pluripotent stem cells (PSCs), which can form any tissue type in the body,

Although it looks like a panel painting, this object is actually the upper cover of an Unidentified Himalayan Manuscript that dates from 14th Century. The wooden cover has two distinct sides with a detailed painting of twelve dancing goddesses on one side, and gilded carvings on the other. Although we do not know from exactly where it came, it is likely that it was housed in a library like this one, in the main monastery of Gyantse Monastery, Tsang, Tibet.

The smooth, painted side of the manuscript cover with its delicate painting would actually face inwards, towards the manuscript’s pages. The fact that it was not exposed to the outside may be why the painting is in such good condition while the other, carved side that faces outwards has lost much of its paint and gilding.

In modern times, the smooth surface of the cover had been coated with a layer of wax-like material. This coating was thick in some areas, like areas of paint loss, and thinner in others. Because of its tacky texture the coating had attracted dust and fibers. Matte in some areas and shiny in others, the coating detracted from the intricate details of the composition.

The goal of the conservation treatment therefore, was to remove the dirty, uneven coating without affecting the paint layers. Two techniques helped determine how this could be done in a safe and even manner. First, a small sample was taken to create a cross section that could be analyzed under magnification in different types of light. This showed how many layers the painting was composed of and the coatings on top of them. Removing the topmost layer, the layer that looks clear/bluish in the UV photo micrograph, above the brighter white layer, was made the priority. 

This was the layer that had attracted the disfiguring dust and once removed with the a cotton swab it appears yellow/brown.

Next, once treatment had begun, an ultraviolet reflected photograph (UVR) was taken to show where this layer had been removed. 

In the UVR photograph, the remaining coating shows up darker and can be seen on the right side of the panel. This type of photography will help us to determine that the coating is removed evenly and completely.

More information: Bo Li et al, The retromer complex safeguards against neural progenitor-derived tumorigenesis by regulating notch receptor trafficking, eLife (2018). DOI: 10.7554/eLife.38181 

Unpacking Asymmetric Cell Division

Stem cells are the basic material from which mature, specialised cells such as muscle and blood cells are produced — this process is known as differentiation. One way that stem cells do this without depleting themselves is through asymmetric cell division. Through asymmetric division, a stem cell produces a new stem cell and another cell that undergoes differentiation, producing a mature cell.

Studies on neural stem cells (NSCs) from fruit fly larvae have made huge contribution to our understanding of asymmetric division. Understanding asymmetric division is important because disruption of this process can result in excess NSCs formation or failure to produce mature brain cells, which in turn can cause tumour formation or neurodevelopmental disorders.

While previous studies have established that a certain type of membrane lipids called phosphatidylinositol (PI) lipids is involved asymmetry of several cell types, the role of PI lipids in asymmetric division of NSCs is not well understood. In a new study, scientists sought to understand the role of PI lipids in fruit fly neural stem cells, and focused on two proteins critical for the biosynthesis of membrane lipids: phosphatidylinositol transfer proteins (PITPs) and PI4KIIIα. The study was led by Associate Professor Wang Hongyan, Deputy Director of Neuroscience & Behavioral Disorders Program from Duke-NUS Medical School, Singapore, and her collaborators from Texas A&A University in the United States and Mechanobiology Institute of the National University of Singapore.

These proteins were chosen because the counterparts of both proteins in mammals are associated with neurodegenerative disorders such as Alzheimer’s, Parkinson’s and Huntington’s, and cancers. Notably, the team found a new role for a PITP protein called Vibrator, which along with PI4KIIIα, play important roles in asymmetric division, a complex process that involves numerous players acting on each other. They noted that the lipid binding and transfer activities are particularly important for asymmetric division.

The team also found evidence that the mouse counterparts complement the phenotypes of fly vibrator mutants in the brains. While this implies that their work likely extends to mammals, further work will be needed to confirm if the roles of the proteins and lipids Professor Wang and her team elucidated are the same as in mammals.

Rosalind Franklin, whose work first uncovered the structure of DNA, was born on this day in 1920.

It has often been claimed that humans learn language using brain components that are specifically dedicated to this purpose. Now, new evidence strongly suggests that language is in fact learned in brain systems that are also used for many other purposes and even pre-existed humans, say researchers in PNAS.

The research combines results from multiple studies involving a total of 665 participants. It shows that children learn their native language and adults learn foreign languages in evolutionarily ancient brain circuits that also are used for tasks as diverse as remembering a shopping list and learning to drive.

“Our conclusion that language is learned in such ancient general-purpose systems contrasts with the long-standing theory that language depends on innately-specified language modules found only in humans,” says the study’s senior investigator, Michael T. Ullman, PhD, professor of neuroscience at Georgetown University School of Medicine.

“These brain systems are also found in animals — for example, rats use them when they learn to navigate a maze,” says co-author Phillip Hamrick, PhD, of Kent State University. “Whatever changes these systems might have undergone to support language, the fact that they play an important role in this critical human ability is quite remarkable.”

The study has important implications not only for understanding the biology and evolution of language and how it is learned, but also for how language learning can be improved, both for people learning a foreign language and for those with language disorders such as autism, dyslexia, or aphasia (language problems caused by brain damage such as stroke).

The research statistically synthesized findings from 16 studies that examined language learning in two well-studied brain systems: declarative and procedural memory.

The results showed that how good we are at remembering the words of a language correlates with how good we are at learning in declarative memory, which we use to memorize shopping lists or to remember the bus driver’s face or what we ate for dinner last night.  

Grammar abilities, which allow us to combine words into sentences according to the rules of a language, showed a different pattern. The grammar abilities of children acquiring their native language correlated most strongly with learning in procedural memory, which we use to learn tasks such as driving, riding a bicycle, or playing a musical instrument. In adults learning a foreign language, however, grammar correlated with declarative memory at earlier stages of language learning, but with procedural memory at later stages.

The correlations were large, and were found consistently across languages (e.g., English, French, Finnish, and Japanese) and tasks (e.g., reading, listening, and speaking tasks), suggesting that the links between language and the brain systems are robust and reliable.

The findings have broad research, educational, and clinical implications, says co-author Jarrad Lum, PhD, of Deakin University in Australia.

“Researchers still know very little about the genetic and biological bases of language learning, and the new findings may lead to advances in these areas,” says Ullman. “We know much more about the genetics and biology of the brain systems than about these same aspects of language learning. Since our results suggest that language learning depends on the brain systems, the genetics, biology, and learning mechanisms of these systems may very well also hold for language.”

For example, though researchers know little about which genes underlie language, numerous genes playing particular roles in the two brain systems have been identified. The findings from this new study suggest that these genes may also play similar roles in language. Along the same lines, the evolution of these brain systems, and how they came to underlie language, should shed light on the evolution of language.

Additionally, the findings may lead to approaches that could improve foreign language learning and language problems in disorders, Ullman says.

For example, various pharmacological agents (e.g., the drug memantine) and behavioral strategies (e.g., spacing out the presentation of information) have been shown to enhance learning or retention of information in the brain systems, he says. These approaches may thus also be used to facilitate language learning, including in disorders such as aphasia, dyslexia, and autism.

“We hope and believe that this study will lead to exciting advances in our understanding of language, and in how both second language learning and language problems can be improved,” Ullman concludes.

Lying in a Foreign Language is Easier

Most people find it easier to lie in a foreign language than in their native tongue. However, things are different when telling the truth.

Deaf children learn words faster than hearing children

According to estimates by the Robert Koch Institute, up to two thousand hearing impaired children are born in Germany each year. For some of them a cochlear implant can offer relief. Until now, it was not clear which processes take place in the affected children when they start to learn language later than their contemporaries with normal hearing—and why they differ in their success to reach a normal level of language. A current study at the Max Planck Institute for Human Cognitive and Brain Sciences (MPI CBS) in Leipzig and University Medical Centre Dresden found that deaf children with a cochlear implant learn words even faster than those with normal hearing. This finding can help refine the search for the reasons behind their varying success in language acquisition.

For many years scientists tinkered to find a perfect replacement for the damaged or dysplastic inner ear. Cochlear implants receive a sound, convert it into electrical stimuli and send these impulses directly to the auditory nerve, thereby giving hearing impaired children the chance to connect to the world of sounds and noises.

It has so far been assumed that these children reach the language level of children with normal hearing much later. Previous studies showed that from the moment of having the device implanted, children need longer to attain the important steps of learning their mother tongue—for instance, being able to distinguish the rhythm of their mother tongue from that of another language. This could imply that developmental milestones necessary to start school are also delayed, although they reach all the other developmental stages needed.

A current study at the Max Planck Institute for Human Cognitive and Brain Sciences (MPI CBS) in Leipzig and the University Medical Centre Dresden has now revealed something different: “We observed that when deaf children get their implants, they learn words faster than those with normal hearing. Consequently, they build up certain word pools faster”, says Niki Vavatzanidis, first author of the underlying study and scientist at MPI CBS and the University Medical Centre Dresden. Normally, children need fourteen months to reliably recognise that known objects are named incorrectly. Children with an artificial cochlea were already able to do so after twelve months.

The reason for this finding could be that children with cochlear implants are older when they are first exposed to spoken language. Those with normal hearing learn aspects of language, such as the rhythm and melody of their mother tongue, from birth and even in the womb. In deaf children, this only starts at the time of their cochlear replacement, at the age of around one to four years. By this time certain brain structures necessary for language acquisition are already well developed. “It is not just the memory, but also the broader knowledge about their surroundings that is more formed. They already know about objects in their environment and have accumulated non-linguistic semantic categories” states Vavatzanidis. For example, they already know that objects such as cups or meals could be hot and that heat could be something harmful without knowing the word “hot”.

The neuroscientists examined these relations with the help of thirty-two children with cochlear implant in both ears. They carried out a test after twelve, eighteen and twenty-four months after implantation that tested their ability to recognise words: The young study participants were shown pictures of objects which were named either correctly or incorrectly. In parallel to this, the scientist analysed the brain activities of the little ones using electroencephalography (EEG). If the researchers detected an effect in the EEG known as N400, they knew that the child registered the incorrect word. This means they had established a stable connection between objects and their names. They had learnt the word.

Compound Found in Green Tea and Wine May Block Formation of Toxic Metabolites

Both tannic acid and EGCG were effective in blocking the formation of toxic amyloid structures. The researchers also used computer simulations to verify the mechanism driving the compounds.