New kind of scissors discovered

Professor Chase Beisel and Dr. Oleg Dmytrenko in the Würzburg HIRI laboratory.
Photo Credit: HIRI

Like a Swiss Army knife: a newly discovered component of bacterial immune defense paralyzes infected cells. He could advance molecular biological diagnostics.

Bacteria can also be infected by viruses, and they have developed their own immune defense strategies in this case. Bacterial defense systems such as CRISPR-Cas have various proteins and functions that help the bacteria protect themselves against intruders.

The defense is based on a common basic mechanism: a CRISPR ribonucleic acid (crRNA), which serves as a "lead RNA", helps to identify regions of a foreign genome, such as the DNA of a virus, in order to make them specifically harmless. The nuclease led by a crRNA can cut its target like scissors. It is a strategy of nature that humans have made use of technologically in a variety of ways.

"When you consider how well different nucleases have been implemented in new and improved technologies, any discovery in this area could bring new benefits to society," Professor Chase Beisel describes a research motivation of his laboratory at the Helmholtz Institute for RNA-based in Würzburg Infection research (HIRI). The facility is a location of the Helmholtz Center for Infection Research in Braunschweig in cooperation with the Julius Maximilians University, to which Chase Beisel is the head of the chair for synthetic RNA biology.

Climate change could cause “disaster” in the world’s oceans

J. Keith Moore, UCI professor of Earth system science, says, “… unchecked global warming could lead to a shutdown of the ocean deep circulation. This would be a climate disaster similar in magnitude to complete melting of the ice sheets on land.”
Photo Credit: Steve Zylius / UCI

Climate-driven heating of seawater is causing a slowdown of deep circulation patterns in the Atlantic and Southern oceans, according to University of California, Irvine Earth system scientists, and if this process continues, the ocean’s ability to remove carbon dioxide from the atmosphere will be severely limited, further exacerbating global warming.

In a recent study published in Nature Climate Change, these researchers analyzed projections from three dozen climate models and found that the Atlantic Meridional Overturning Circulation and the Southern Meridional Overturning Circulation will slow by as much as 42 percent by 2100. The simulations suggest that under worst-case warming, the SMOC could cease entirely by 2300.

“Analysis of the projections from 36 Earth system models over a range of climate scenarios shows that unchecked global warming could lead to a shutdown of the ocean deep circulation,” said co-author J. Keith Moore, UCI professor of Earth system science. “This would be a climate disaster similar in magnitude to complete melting of the ice sheets on land.”

Antibiotic residues in water a threat to human health

Photo Credit: Thomas Hoang

Antibiotic residues in wastewater and wastewater treatment plants in regions around China and India risk contributing to antibiotic resistance, and the drinking water may pose a threat to human health, according to an analysis from Karolinska Institutet published in The Lancet Planetary Health. The researchers also determined the relative contribution of various sources of antibiotic contamination in waterways, such as hospitals, municipals, livestock, and pharmaceutical manufacturing.

” Our results can help decision-makers to target risk reduction measures against environmental residues of priority antibiotics and in high-risk sites, to protect human health and the environment,” says Nada Hanna, researcher at the Department of Global Public Health at Karolinska Institutet, and the study’s first author. “Allocating these resources efficiently is especially vital for resource-poor countries that produce large amounts of antibiotics.”

Bacteria that become resistant to antibiotics are a global threat that can lead to untreatable bacterial infections in animals and humans.

Antibiotics can enter the environment during their production, consumption and disposal. Antibiotic residues in the environment, such as in wastewater and drinking water, can contribute to the emergence and spread of resistance.

Effects of highly pathogenic avian influenza on canids investigated

When the H5N1 HPAI virus (orange) affected a flock of crows in a public garden, it caused a mass die-off of crows. An Ezo red fox and a Japanese raccoon dog were also infected by the H5N1 HPAI virus, the former likely by consuming corpses of the crows, and the latter due to close contact with crow corpses
Illustration Credit: Takahiro Hiono

Researchers at Hokkaido University have revealed the effects of high pathogenicity avian influenza virus infection on an Ezo red fox and a Japanese raccoon dog, linking their infection to a recorded die-off of crows.

High Pathogenicity Avian Influenza (HPAI), commonly known as a type of bird flu, is caused by a group of influenza viruses that affect birds. Humans are very rarely infected by this virus. The most well-known HPAI viral subtype is H5N1, first reported in 1996 for its infection in geese, and then found in humans since 1997. A great amount of time and resources are devoted to monitoring and tracking the spread of HPAI across the globe, due to its disruptive potential on poultry farming—outbreaks are contained by culling exposed and infected flocks.

How to turn a tentacle into a foot

Hydra with reduced Zic4 content. The red arrowheads indicate the tentacles that have been transformed into feet, the asterisk indicates the animal's mouth.
Illustration Credit:  Galliot, Brigitte CC-BY-NC

By identifying a key cell identity regulator, a team from UNIGE and the IMF has managed to modify the structure and function of tentacle cells in the hydra.

Humans, animals, plants: all multicellular organisms consist of so-called differentiated specialized cells. Thus, the cells that make up the epidermis do not have the same identity - nor the same function - as those that line the digestive system, for example. However, the mechanisms allowing these cells to maintain their identity are still poorly understood. Working on hydra, a team from the University of Geneva (UNIGE), in collaboration with the Friedrich Miescher Institute for Biomedical Research (IMF) in Basel, discovered one of the key regulators: the factor of transcription Zic4. After reducing its expression, researchers have found that the tentacle cells of the hydra change their identity and turn into foot cells, forming functional feet in the animal's head. These results are to be discovered in the journal Science Advances.

Reef fish must relearn 'rules of engagement' after coral bleaching

butterfly fish
Photo Credit: Светлана

Mass coral bleaching events are making it harder for some species of reef fish to identify competitors, new research reveals.

Scientists studying reefs across five Indo-Pacific regions found that the ability of butterfly fish individuals to identify competitor species and respond appropriately was compromised after widespread loss of coral caused by bleaching.

This change means they make poorer decisions that leave them less able to avoid unnecessary fights, using up precious limited energy. The scientists behind the study believe these changes could have implications for species survival as further global warming increases the likelihood of coral loss.

“By recognizing a competitor, individual fish can make decisions about whether to escalate, or retreat from, a contest—conserving valuable energy and avoiding injuries,” said Sally Keith, a senior lecturer in marine biology at Lancaster University and lead author of the study.

Researchers detect fluoride in water with new simple color change test

Photo Credit: Henryk Niestrój

Test is first to use artificial cell sensors to detect environmental contaminant

A team of synthetic biologists at Northwestern is developing a sensor platform that will be able to detect a range of environmental and biological targets in real-world samples.

Environmental contaminants like fluoride, lead and pesticides exist all around and even within us. While researchers have simple ways to measure concentrations of such contaminants inside lab environments, levels are much more difficult to test in the field. That’s because they require costly specialized equipment.

Recent efforts in synthetic biology have leveraged cellular biosensors to both detect and report environmental contaminants in a cost-effective and field-deployable manner. Even as progress is being made, scientists have struggled to answer the question of how to protect sensor components from substances that naturally exist in extracted samples.

First-ever observation of quantum interference between dissimilar particles

Daniel Brandenburg and Zhangbu Xu at the STAR detector of the Relativistic Heavy Ion Collider (RHIC).
Photo Credit: Courtesy of Brookhaven National Laboratory

Nuclear physicists have found a new way to use the Relativistic Heavy Ion Collider (RHIC)—a particle collider at the U.S. Department of Energy’s (DOE) Brookhaven National Laboratory—to see the shape and details inside atomic nuclei. The method relies on particles of light that surround gold ions as they speed around the collider and a new type of quantum entanglement that’s never been seen before.

Through a series of quantum fluctuations, the particles of light (a.k.a. photons) interact with gluons—gluelike particles that hold quarks together within the protons and neutrons of nuclei. Those interactions produce an intermediate particle that quickly decays into two differently charged “pions” (π). By measuring the velocity and angles at which these π+ and π- particles strike RHIC’s STAR detector, the scientists can backtrack to get crucial information about the photon—and use that to map out the arrangement of gluons within the nucleus with higher precision than ever before.

“This technique is similar to the way doctors use positron emission tomography (PET scans) to see what’s happening inside the brain and other body parts,” said former Brookhaven Lab physicist James Daniel Brandenburg, a member of the STAR collaboration who joined The Ohio State University as an assistant professor in January 2023. “But in this case, we’re talking about mapping out features on the scale of femtometers—quadrillionths of a meter—the size of an individual proton.”

‘Veggie’ dinosaurs differed in how they ate their food

Some of the finite element models compared bite performance across the five ornithischian dinosaurs in the study, with different models showing different bite points. Cooler colors (blue) represent areas of low stress while hot colors (red and pink) indicate areas that are highly stressed.
Illustration Credit: David Button

Although most early dinosaurs were vegetarian, there were a surprising number of differences in the way that these animals tackled eating a plant-based diet, according to a new study by scientists from the Natural History Museum and the Universities of Bristol and Birmingham.

Scientists used CT scans of dinosaur skulls to track the evolution of early dinosaur herbivores - reconstructing jaw muscles and measuring the animals’ bite force to understand how dinosaur feeding evolved.

Five skulls from the plant-eating group Ornithischia provided the key to unlocking their feeding habits: Heterodontosaurus, Lesothosaurus, Scelidosaurus, Hypsilophodon and Psittacosaurus - earliest representatives of what would become the major herbivore dinosaur groups.

Later ornithischian dinosaurs, like Triceratops and Stegosaurus, show a wide range of adaptations to eating plants yet their early relatives have not been examined properly, until now.

How a CRISPR Protein Might Yield New Tests for Many Viruses

In this illustration based on cryo-electron microscope images, a Cas12a2 protein unzips a DNA double helix, allowing it to cut the single strands of DNA (blue and green).
Illustration Credit: Jack Bravo/University of Texas at Austin

In a first for the genetic toolset known as CRISPR, a recently discovered protein has been found to act as a kind of multipurpose self-destruct system for bacteria, capable of degrading single-stranded RNA, single-stranded DNA and double-stranded DNA. With its abilities to target so many types of genetic material, the discovery holds potential for the development of new inexpensive and highly sensitive at-home diagnostic tests for a wide range of infectious diseases, including COVID-19, influenza, Ebola and Zika, according to the authors of a new study in the journal Nature.

Using a high-resolution imaging technique called cryo-EM, the team discovered that when this protein, named Cas12a2, binds to a specific sequence of genetic material from a potentially dangerous virus, called a target RNA, a side portion of Cas12a2 swings out to reveal an active site, similar to a sprung-open switchblade knife. Then, the active site starts to indiscriminately cut any genetic material it comes into contact with. The researchers discovered that, with a single mutation to the Cas12a2 protein, the active site degrades only single-stranded DNA—a feature especially useful in developing new diagnostics tailored for any of a wide range of viruses.