How Cells Find the Right Partners

Fluorescence microscopy images of Drosophila egg chambers of different developmental stages. Eya in the epithelial cells is depicted in orange.
Image Credit: Vanessa Weichselberger/University of Freiburg

During the growth and development of living organisms, different types of cells must come into contact with each other in order to form tissues and organs together. A small team working with Prof. Dr. Anne Classen of the Excellence Cluster CIBSS – Centre for Integrative Biological Signaling Studies of the University of Freiburg has discovered that complex changes in form, or morphogenesis, during development are driven exclusively via the affinity of cells to each other. The researchers examined the egg chambers of fruit flies (Drosophila melanogaster) and combined genetic methods and mathematical modeling in their work. The study has been published in the scientific journal Nature Communications.

Complex organization processes in egg chamber

The lead author of the study and a member of Classen’s lab, Dr. Vanessa Weichselberger, summarized the team’s work: “We wanted to find out how different types of cells organize their morphogenesis with each other in order to form functional units.” She continues, “The egg chamber is a good example, because within it, different cell populations must self-organize into functional units.” The egg chamber is the structure in which an immature egg cell, or oocyte, matures until it is ready for fertilization. Drosophila’s egg chamber looks like a tiny football. Inside, the growing egg cell is located on one side, and on the other are 15 nurse cells that provide nutrients for the immature egg cell. In order to produce an egg, the egg cell must mature, while the nurse cells are ultimately removed.

Both processes – the maturation of the egg cell and the removal of the nurse cells, are dependent on an external layer of epithelial cells. For this purpose, the epithelial cells are divided into specialized groups, which – based on their function – must either make contact with the nurse cells or the egg cell. This partnering between the inner and outer cells is a complex process which takes place while simultaneously the size relationships within the egg chamber continually change. “Until now, the mechanisms that could robustly control such a dynamic process were unknown,” says Classen.

Sikorsky And DARPA's Autonomous Black Hawk® Flies Logistics and Rescue Missions Without Pilots on Board

SikorskyOPVBlackHawkYuma2022
Sikorsky demonstrates to the U.S. Army for the first time how an optionally piloted Black Hawk helicopter flying in autonomous mode could resupply forward forces. These uninhabited Black Hawk flights occurred in October at Yuma Proving Ground in Arizona.
Photo Credit: Sikorsky, a Lockheed Martin company.

Sikorsky, a Lockheed Martin company (NYSE: LMT) and the Defense Advanced Research Projects Agency (DARPA) have successfully demonstrated to the U.S. Army for the first time how an uninhabited Black Hawk helicopter flying autonomously can safely and reliably perform internal and external cargo resupply missions, and a rescue operation.

Performed Oct. 12, 14 and 18 as part of the U.S. Army's Project Convergence 2022 (PC22) experiment, the flights show how existing and future piloted utility helicopters could one day fly complex missions in reduced crew or autonomous mode. This would give Army commanders and aviators greater flexibility in how and when aircraft and pilots are used, especially in limited visibility or contested environments.

Why It Matters

Sikorsky is partnered with DARPA to develop autonomy technology that will exponentially improve the flight safety and efficiency of rotary and fixed-wing aircraft. Sikorsky's autonomy system, known as MATRIX™ technology, forms the core of DARPA's ALIAS (Aircrew Labor In-cockpit Automation System) project.

Infants are less likely to contract COVID, develop severe symptoms than other household caregivers

Image by Pexels

Infants whose mothers test positive for COVID-19 tend to develop less-severe symptoms than their parents, if they become infected with the virus at all.

In one of the first studies to explore how COVID-19 specifically affects older infants, researchers from the University of Washington and at institutions at four other locations in the Western and Southern U.S. found that the number of infected people in a household was the factor most closely linked with the infant’s likelihood of being infected.

“The focus on infants early in the pandemic was about possible transmission risks during pregnancy, birth or through breastfeeding, but there were other questions about the risks in the household to infants and other children when caregivers are sick,” said Melanie Martin, assistant professor of anthropology at the UW and the first author of the study, which in the journal Frontiers in Immunology. “Infants are in the most contact, and very close contact, with their caregiver than with any other family members. And so, we asked, "How much are infants at risk, and how do you protect children when they are sick?”

The study analyzed surveys and antibody results (taken from pin-prick blood samples) of 46 pairs of COVID-positive mothers and their infants for two months following maternal infection. Infants were at least 1 month old, and COVID-positive mothers were enrolled in the study within days, sometimes hours, of receiving their positive PCR test results. The researchers also recruited a comparative group of 11 COVID-negative mothers, who tested negative after exposure or symptoms, and a control group of 26 mothers with no known COVID exposures or symptoms.

Why fish look down when they swim

Field site in Tumprop, India. The researchers collected video data a forested stream with a sandy substrate and low-to-medium flow.
Photo Credit: E. Alexander/Northwestern University

Just as you might look down at the sidewalk as you walk, fish look downward when they swim, a new study by a Northwestern University-led international collaboration has confirmed.

The study is the first to combine simulations of zebrafish’s brain, native environment and spatially-varying swimming behavior into one computational model. By analyzing this model, the researchers concluded that this quirk — looking down while swimming forward — is an adaptive behavior that evolved to help the fish self-stabilize, as when swimming against a current.

As water moves, fish are constantly trying to self-stabilize in order to stay in place — rather than getting swept away in a moving stream. Focusing on other fish, plants or debris might give the fish a false sensation that it’s moving. The stable riverbed below them, however, gives fish more reliable information about their swimming direction and speed.

“It’s similar to sitting on a train car that isn’t moving. If the train next to yours starts to pull to away from the station, it can trick you into thinking you are moving too,” said Northwestern’s Emma Alexander, who led the study. “The visual cue from the other train is so strong that it overrides the fact that all of your other senses are telling you that you are sitting still. That’s exactly the same phenomenon that we are studying in fish. There are many misleading motion cues above them, but the most abundant and reliable signals are from the bottom of the river.”

The study was published today (Nov. 2) in the journal Current Biology.

Alexander is an assistant professor of computer science in Northwestern’s McCormick School of Engineering, where she runs the Bio Inspired Vision Lab.

New 3D model shows how cadmium exposure may affect heart development

2D model showing how the pluripotent stem cells react to human relevant doses of cadmium over 8 days. From the control in the first panel, to the last panel, researchers can see how the differentiation to cardiomyocytes is inhibited with different doses of cadmium.
Credit: National Institutes of Health

NIH researchers develop new tools to demonstrate how environmental agents can lead to diseases.

Researchers have developed a three-dimensional model that shows how exposure to cadmium might lead to congenital heart disease. Affecting nearly 40,000 newborns a year, congenital heart disease is the most common type of birth defect in the United States. The model was created by scientists at the National Institute of Environmental Health Sciences (NIEHS), part of the National Institutes of Health.

Cadmium is a metal that can be released into the environment through mining and various industrial processes, and it has been found in air, soil, water, and tobacco. The metal can enter the food chain when plants absorb it from soil. Previous studies suggested that maternal exposure to cadmium might be a significant risk factor for congenital heart disease.

Using models derived from human cells and tissues, called in vitro models, researchers designed a 3D organoid model that mimics how the human heart develops. The researchers saw how exposure to low levels of cadmium can block usual formation of cardiomyocytes, which are the major type of cells that form the heart. In doing so, they revealed the biological mechanisms that might explain how cadmium could induce heart abnormalities.

Blind spots when monitoring plastic waste

The researchers used river models that were filled with plastic waste for their investigation
Photo Credit: Daniel Valero, KIT

Whether in drinking water, in food or even in the air: plastic is a global problem - and the full extent of the pollution may not be known yet. Researchers at the Karlsruhe Institute of Technology (KIT), together with partners from the Netherlands and Australia, have reviewed conventional assumptions for the transport of plastic in rivers. The actual amount of plastic waste in rivers could therefore be up to 90 percent larger than previously thought. The new findings are intended to help improve monitoring and remove plastic from water. They report on their results in the journal Water Research.

Rivers play a key role in the transportation of plastic in the environment. "As soon as plastic gets into a river, it is transported at high speed and spread in the environment," says Dr. Daniel Valero from the KIT Institute for Water and Water Development and lead author of the current study on plastic transport. “But depending on the size and nature, plastic can behave very differently. It can be dipped, swimming or stopped by obstacles. "Current methods for estimating plastic pollution in rivers are based as standard but mainly on surface observations. “This is the only way to effectively monitor large rivers from bridges. However, the underlying assumptions have not yet been adequately reviewed,” said Valero.

500 million year-old fossils reveal answer to evolutionary riddle

Fossil specimen (left) and diagram (right) of Gangtoucunia aspera preserving soft tissues, including the gut and tentacle.
Image Credit: Luke Parry and Guangxu Zhang.

An exceptionally well-preserved collection of fossils discovered in eastern Yunnan Province, China, has enabled researchers to solve a centuries-old riddle in the evolution of life on earth, revealing what the first animals to make skeletons looked like. The results have been published today in Proceedings of the Royal Society B.

The first animals to build hard and robust skeletons appear suddenly in the fossil record in a geological blink of an eye around 550-520 million years ago during an event called the Cambrian Explosion. Many of these early fossils are simple hollow tubes ranging from a few millimetres to many centimetres in length. However, what sort of animals made these skeletons was almost completely unknown, because they lack preservation of the soft parts needed to identify them as belonging to major groups of animals that are still alive today.

The new collection of 514-million-year-old fossils includes four specimens of Gangtoucunia aspera with soft tissues still intact, including the gut and mouthparts. These reveal that this species had a mouth fringed with a ring of smooth, unbranched tentacles about 5 mm long. It’s likely that these were used to sting and capture prey, such as small arthropods. The fossils also show that Gangtoucunia had a blind-ended gut (open only at one end), partitioned into internal cavities, that filled the length of the tube.

Study urges caution when comparing neural networks to the brain

Neural networks, a type of computing system loosely modeled on the organization of the human brain, form the basis of many artificial intelligence systems for applications such speech recognition, computer vision, and medical image analysis.
Image Credits: Christine Daniloff | Massachusetts Institute of Technology

Neural networks, a type of computing system loosely modeled on the organization of the human brain, form the basis of many artificial intelligence systems for applications such speech recognition, computer vision, and medical image analysis.

In the field of neuroscience, researchers often use neural networks to try to model the same kind of tasks that the brain performs, in hopes that the models could suggest new hypotheses regarding how the brain itself performs those tasks. However, a group of researchers at MIT is urging that more caution should be taken when interpreting these models.

In an analysis of more than 11,000 neural networks that were trained to simulate the function of grid cells — key components of the brain’s navigation system — the researchers found that neural networks only produced grid-cell-like activity when they were given very specific constraints that are not found in biological systems.

“What this suggests is that in order to obtain a result with grid cells, the researchers training the models needed to bake in those results with specific, biologically implausible implementation choices,” says Rylan Schaeffer, a former senior research associate at MIT.

Viruses can ‘hitchhike’ on microplastics

Photo Credit: Naja Bertolt Jensen

Microplastics are not just tiny particles that can be ingested, they can also carry viruses, a University of Queensland study has revealed.

The study, led by Associate Prof Jianhua Guo and Dr Ji Lu from UQ’s Australian Centre for Water and Environmental Biotechnology (ACWEB), investigated if microplastics have the ability to harbor viruses, including the one found inside E. coli bacteria.

“We often hear about the human and environmental harm caused by microplastics in water, but there is little known about whether the tiny microplastic particles can carry viruses,” Dr Guo said.

“What we found is that viruses can hitchhike on microplastics and prolong their infectivity, which means there could be an increased risk of virus transmission throughout waterways and the environment.”

Dr Lu said they used the E. coli bacteriophage in the study, which is a virus that infects and replicates within the bacteria itself and is not harmful to humans.

Daytime Naps Reinforce Memories of Emotional Trauma and Anxiety

According to Yuri Pavlov, the positive effect of sleep on memory can be observed years later.
Photo Credit: Nadezhda Pavlova

Scientists from Ural Federal University and the University of Tübingen (Germany) studied the effect of sleep on the formation and translation of primary memories of something scary into long-term memory. Neurobiologists discovered that sleeping during the day strengthens memory of disturbing and frightening events, but a similar effect of memory strengthening is also observed after a period of calm wakefulness. The findings will be useful for developing rehabilitation strategies for people who have been emotionally traumatized by disasters, warfare, and violence. The study was published in the journal Cognitive, Affective, & Behavioral Neuroscience.

Memory consolidation - the transition of memories from short-term memory to long-term memory - occurs primarily during sleep. Studies show that sleep after learning can have positive effects that are superior to passive wakefulness. This occurs by reactivating important memories, which may also be reflected in dreams. The positive effects of dreaming can be observed even years later. However, there are currently no studies that analyze whether sleep enhances the effect of remembering emotionally difficult events. Therefore, scientists decided to find out how sleep affects the memory of a person's experience of fear.

Method to char­ac­ter­ize large quan­tum com­put­ers

View inside an ion trap, the heart of an ion trap quantum computer. 
Credit: C Lackner/Quantum Optics and Spectroscopy Group, University of Innsbruck

Quantum devices are becoming ever more complex and powerful. Researchers at the University of Innsbruck, in collaboration with the Johannes Kepler University Linz and the University of Technology Sydney, are now presenting a method to characterize even large quantum computers using only a single measurement setting.

The gold-standard for the characterization of quantum devices is so-called quantum tomography, which in analogy to medical tomography, can draw a complete picture of a quantum system from a series of snapshots of the system. While offering plenty of insights, the number of measurements required for tomography increases rapidly, with three times as many measurements required for every additional qubit. Due to the sheer time it takes to perform all these measurements, tomography has only been possible on devices with a handful of qubits. However, recent developments on quantum computers have successfully scaled up system sizes much beyond the capabilities of tomography, making their characterization a daunting bottleneck.

A new method for studying ribosome function

Illustration showing the principle of native chemical ligation approach developed by Syroegin, et al. Addition of the cysteine amino acid (red) to tRNA (blue, top left) allows for the tRNA to fuse to a peptide (yellow, lower left). The resulting ribosome structure (middle) and the captured electron density maps for the peptidyl-tRNA inside the ribosome (right) were obtained by X-ray crystallography in the UIC experiments.
Image Credit: Syroegin, et al.

Inside tiny cellular machines called ribosomes, chains of genetic material called messenger RNAs (mRNAs) are matched with the corresponding transfer RNAs (tRNAs) to create sequences of amino acids that exit the ribosome as proteins. Unfinished proteins are called nascent chainsm and they are left attached to the ribosome.

Scientists know that some of these nascent chains can regulate the activity of the ribosome and that the nascent chains can sometimes interfere with antibiotics — many of which work by targeting bacterial ribosome activity. Scientists do not know why this happens, mainly because it is hard to visualize what the ribosome-peptide-drug interactions look like while the unfinished proteins are still tethered to the ribosome.

Now, scientists at the University of Illinois Chicago are the first to report a method for stable attachment of peptides to tRNAs, which has allowed them to gain new fundamental insights into ribosome function by determining the atomic-level structures of ribosomes and the shapes that these peptides take inside the ribosome.

How much microplastic do whales eat? Up to 10 million pieces per day

Humpback whales lunge feed in Monterey Bay. New research shows whales are ingesting plastic in larger quantities than previously thought, and nearly all comes from their prey, not from the enormous volumes of seawater the whales gulp when feeding.
Photo Credit: shadowfaxone

Analysis of ocean plastic pollution and whale foraging behavior tracked with noninvasive tags shows whales are ingesting tiny specks of plastic in far bigger quantities than previously thought, and nearly all of it comes from the animals they eat – not the water they gulp.

The largest animals ever known to have lived on Earth ingest the tiniest specks of plastic in colossal amounts, Stanford University scientists have found.

Published in Nature Communications, the study focuses on blue, fin, and humpback whales and their consumption of plastic fragments no bigger than a few grains of sand, which are commonly called microplastics. The authors combined measures of microplastic concentrations up and down the water column off the coast of California with detailed logs of where hundreds of whales carrying tracking devices foraged for food between 2010 and 2019.

They found the whales predominantly feed 50 to 250 meters below the surface, a depth that coincides with the highest concentrations of microplastic in the open ocean. The planet’s biggest creature – the blue whale – ingests the most plastic, at an estimated 10 million pieces per day as it feeds almost exclusively on shrimplike animals called krill.

“They’re lower on the food chain than you might expect by their massive size, which puts them closer to where the plastic is in the water. There’s only one link: The krill eats the plastic, and then the whale eats the krill,” said study co-author Matthew Savoca, a postdoctoral scholar at Hopkins Marine Station, Stanford’s marine laboratory on the Monterey Peninsula.

Arctic Hydrothermal Vent Site Could Help in Search for Extraterrestrial Life

The view from over ice-floes in the Arctic Ocean, covering the Aurora hydrothermal Field, Gakkel Ridge from the R/V Polarstern.
Photo Credit Chris German, ©Woods Hole Oceanographic Institution

When scientists discovered a hydrothermal vent site in the Arctic Ocean’s Aurora hydrothermal system in 2014, they did not immediately realize just how exciting their discovery was.

“Although finding any vent in the Arctic Ocean was a first, we figured what we had found was one of the least interesting kinds of vent sites that there are,” said Chris German, senior scientist with the Woods Hole Oceanographic Institution’s Department of Geology and Geophysics. “We came home from the expedition thinking, ‘Okay, we found a site in the Arctic. That’s great, but if you take away the ice-cover, it is just another vent site’.”

However, after further analysis and a follow-on 2019 expedition to the remote site, German and other researchers now think this is a very significant finding. They believe that this vent—and others still to be located within the Arctic Ocean’s Gakkel Ridge rift-valley floor—could change our understanding of ultra-slow spreading mid-ocean ridges, substantially expand the estimates of valuable marine mineral deposits rich in copper and gold and serve as natural laboratories to help inform the search for extraterrestrial life.

“Our findings have implications for ultra-slow ridge cooling, global marine mineral distributions, and the diversity of geologic settings that can host abiotic organic synthesis–pertinent to the search for life beyond Earth,” according to the paper, “Volcanically hosted venting with indications of ultramafic influence at Aurora hydrothermal field on Gakkel Ridge,” published in Nature Communications.

A New Protocol for Live Imaging Emerges from MBL Embryology Course

A stylized image of a nematode worm (C. elegans) adult encircled by embryos.
Credit: Yicong Wu

The beauty of live-imaging studies is that the specimen is alive, allowing dynamics such as cell division and embryonic development to be recorded over time.

Yet the frustration of live-imaging studies is the specimen is alive – wriggling, twisting, escaping the field of view. Plus, it’s delicate, susceptible to heat damage or death from the imaging equipment itself.

A technical solution to this quandary recently emerged from the MBL Embryology course, in “a classic example of the collaborative effort here at MBL,” says MBL Imaging Research Specialist Carsten Wolff.

“During the 2021 Embryology course, we started to develop a technique that enables us to image adult C. elegans worms for longer periods of time, and at high resolution, using light sheet microscopy,” says Wolff. A group of course faculty and staff, collaborating with MBL imagers, fine-tuned the protocol during the 2022 course and wrote up the paper, which is published this month in Frontiers in Cell and Developmental Biology.

The nematode C. elegans is a popular organism in biological and biomedical research. Light-sheet fluorescence microscopy (LSFM) has been very successful in capturing embryonic processes in C. elegans, as well as in mice and zebrafish. But once the organisms hatch out, LSFM presents limitations.