CSHL Professor and HHMI Investigator Zachary Lippman and his team discovered that tomato and Arabidopsis thaliana plants can use very different regulatory systems to control the same exact gene. Incredibly, they linked this behavior to extreme genetic makeovers that occurred over 125 million years of evolution.

The scientists used genome editing to create over 70 mutant strains of tomato and Arabidopsis thaliana plants. Each mutation deleted a piece of regulatory DNA around a gene known as CLV3. They then analyzed the effect each mutation had on plant growth and development. When the DNA keeping CLV3 in check was mutated too much, fruit growth exploded.

Danielle Ciren, a recent CSHL School of Biological Sciences graduate who led this study, explains, “CLV3 helps plants develop normally. If it wasn’t turned on at the exact time that it is, then plants would look very different. All the fruits would be ginormous and not ideal. You have to balance growth and yield. If a plant has giant tomatoes but only two, is that as beneficial as a lower yield? There’s no simple solution. You’re always sacrificing something when you’re trying to get something improved.”

For tomatoes, engineering mutations near the beginning but not the end of the CLV3 gene dramatically affected fruit size. For Arabidopsis, areas around both parts of the gene needed to be disrupted. This indicates something happened over the last 125 million years that made the plants evolve differently. Exactly what occurred remains a mystery.

“You can’t go back to the common ancestor because they don’t exist anymore. So it’s hard to say what was the original state and how have things been mixed up,” says Ciren. “The most simple explanation is that there’s a regulatory element that’s conserved in some capacity, and it’s been altered in subtle ways. It is a bit unexpected.”

What is certain is that genetic regulation is not uniform between plant species. Unearthing these genetic differences could help make crop genome engineering more predictable. And that would be a big win not just for science but for farmers and plant breeders across the globe.

Initially detected with NASA’s Hubble Space Telescope, this galaxy — one of the youngest and most distant ever observed — is so bright that it is challenging scientists to understand why. Now, GN-z11 is giving up some of its secrets.

Vigorous Black Hole Is Most Distant Ever Found

A team studying GN-z11 with Webb found the first clear evidence that the galaxy is hosting a central, supermassive black hole that is rapidly accreting matter. Their finding makes this the farthest active supermassive black hole spotted to date.

“We found extremely dense gas that is common in the vicinity of supermassive black holes accreting gas,” explained principal investigator Roberto Maiolino of the Cavendish Laboratory and the Kavli Institute of Cosmology at the University of Cambridge in the United Kingdom. “These were the first clear signatures that GN-z11 is hosting a black hole that is gobbling matter.”

Using Webb, the team also found indications of ionized chemical elements typically observed near accreting supermassive black holes. Additionally, they discovered a very powerful wind being expelled by the galaxy. Such high-velocity winds are typically driven by processes associated with vigorously accreting supermassive black holes.

“Webb’s NIRCam (Near-Infrared Camera) has revealed an extended component, tracing the host galaxy, and a central, compact source whose colors are consistent with those of an accretion disk surrounding a black hole,” said investigator Hannah Übler, also of the Cavendish Laboratory and the Kavli Institute.

Together, this evidence shows that GN-z11 hosts a 2-million-solar-mass, supermassive black hole in a very active phase of consuming matter, which is why it’s so luminous.

Pristine Gas Clump in GN-z11’s Halo Intrigues Researchers

A second team, also led by Maiolino, used Webb’s NIRSpec (Near-Infrared Spectrograph) to find a gaseous clump of helium in the halo surrounding GN-z11.

“The fact that we don’t see anything else beyond helium suggests that this clump must be fairly pristine,” said Maiolino. “This is something that was expected by theory and simulations in the vicinity of particularly massive galaxies from these epochs — that there should be pockets of pristine gas surviving in the halo, and these may collapse and form Population III star clusters.”

Finding the never-before-seen Population III stars — the first generation of stars formed almost entirely from hydrogen and helium — is one of the most important goals of modern astrophysics. These stars are anticipated to be very massive, very luminous, and very hot. Their expected signature is the presence of ionized helium and the absence of chemical elements heavier than helium.

The formation of the first stars and galaxies marks a fundamental shift in cosmic history, during which the universe evolved from a dark and relatively simple state into the highly structured and complex environment we see today.

In future Webb observations, Maiolino, Übler, and their team will explore GN-z11 in greater depth, and they hope to strengthen the case for the Population III stars that may be forming in its halo.

The research on the pristine gas clump in GN-z11’s halo has been accepted for publication by Astronomy & Astrophysics. The results of the study of GN-z11’s black hole were published in the journal Nature on January 17, 2024. The data was obtained as part of the JWST Advanced Deep Extragalactic Survey (JADES), a joint project between the NIRCam and NIRSpec teams.

Until now, assistive dressing robots, designed to help an elderly person or a person with a disability get dressed, have been created in the laboratory as a one-armed machine, but research has shown that this can be uncomfortable for the person in care or impractical.

To tackle this problem, Dr Jihong Zhu, a robotics researcher at the University of York’s Institute for Safe Autonomy, proposed a two-armed assistive dressing scheme, which has not been attempted in previous research, but inspired by caregivers who have demonstrated that specific actions are required to reduce discomfort and distress to the individual in their care.

It is thought that this technology could be significant in the social care system to allow care-workers to spend less time on practical tasks and more time on the health and mental well-being of individuals.

Dr Zhu gathered important information on how care-workers moved during a dressing exercise, through allowing a robot to observe and learn from human movements and then, through AI, generate a model that mimics how human helpers do their task.

This allowed the researchers to gather enough data to illustrate that two hands were needed for dressing and not one, as well as information on the angles that the arms make, and the need for a human to intervene and stop or alter certain movements.

Dr Zhu, from the University of York’s Institute for Safe Autonomy and the School of Physics, Engineering and Technology, said: “We know that practical tasks, such as getting dressed, can be done by a robot, freeing up a care-worker to concentrate more on providing companionship and observing the general well-being of the individual in their care. It has been tested in the laboratory, but for this to work outside of the lab we really needed to understand how care-workers did this task in real-time.

“We adopted a method called learning from demonstration, which means that you don’t need an expert to programme a robot, a human just needs to demonstrate the motion that is required of the robot and the robot learns that action. It was clear that for care workers two arms were needed to properly attend to the needs of individuals with different abilities.

“One hand holds the individual’s hand to guide them comfortably through the arm of a shirt, for example, whilst at the same time the other hand moves the garment up and around or over. With the current one-armed machine scheme a patient is required to do too much work in order for a robot to assist them, moving their arm up in the air or bending it in ways that they might not be able to do.”

The team were also able to build algorithms that made the robotic arm flexible enough in its movements for it to perform the pulling and lifting actions, but also be prevented from making an action by the gentle touch of a human hand, or guided out of an action by a human hand moving the hand left or right, up or down, without the robot resisting.

Dr Zhu said: “Human modelling can really help with efficient and safe human and robot interactions, but it is not only important to ensure it performs the task, but that it can be halted or changed mid-action should an individual desire it. Trust is a significant part of this process, and the next step in this research is testing the robot’s safety limitations and whether it will be accepted by those who need it most.”

The research, in collaboration with researchers from TU Delft and Honda Research Institute Europe, was funded by the Honda Research Institute Europe.