AKAKOR GEOGRAPHICAL EXPLORING

JWST-7329: a rare massive galaxy that formed very early in the Universe. This JWST NIRCAM image shows a red disk galaxy but with images alone it is hard to distinguish from other objects. Spectral analysis of its light with JWST revealed its anomalous nature – it formed around 13 billions years ago even though it contains ~4x more mass in stars than our Milky Way does today. Credit: James Webb Space Telescope

Our understanding of how galaxies form and the nature of dark matter could be completely upended after new observations of a stellar population bigger than the Milky Way from more than 11 billion years ago that should not exist.

A paper published today in Nature details findings using new data from the James Webb Space Telescope (JWST). The results find that a massive galaxy in the early universe—observed 11.5 billion years ago (a cosmic redshift of 3.2)—has an extremely old population of stars formed much earlier—1.5 billion years earlier in time (a redshift of around 11). The observation upends current modeling, as not enough dark matter has built up in sufficient concentrations to seed their formation.

Swinburne University of Technology’s Distinguished Professor Karl Glazebrook led the study and the international team, who used the JWST for spectroscopic observations of this massive quiescent galaxy.

“We’ve been chasing this particular galaxy for seven years and spent hours observing it with the two largest telescopes on earth to figure out how old it was. But it was too red and too faint, and we couldn’t measure it. In the end, we had to go off Earth and use the JWST to confirm its nature.”

The formation of galaxies is a fundamental paradigm underpinning modern astrophysics and predicts a strong decline in the number of massive galaxies in early cosmic times. Extremely massive quiescent galaxies have now been observed as early as one to two billion years after the Big Bang which challenges previous theoretical models.

Distinguished Professor Glazebrook worked with leading researchers all over the world, including Dr. Themiya Nanayakkara, Dr. Lalitwadee Kawinwanichakij, Dr. Colin Jacobs, Dr. Harry Chittenden, Associate Professor Glenn G Kacprzak and Associate Professor Ivo Labbe from Swinburne’s Centre for Astrophysics and Supercomputing.

“This was very much a team effort, from the infrared sky surveys we started in 2010 that led to us identifying this galaxy as unusual, to our many hours on the Keck and Very Large Telescope where we tried, but failed to confirm it, until finally the last year where we spent enormous effort figuring out how to process the JWST data and analyze this spectrum.”

Dr. Themiya Nanayakkara, who led the spectral analysis of the JWST data, says, “We are now going beyond what was possible to confirm the oldest massive quiescent monsters that exist deep in the universe. This pushes the boundaries of our current understanding of how galaxies form and evolve. The key question now is how they form so fast very early in the universe, and what mysterious mechanisms lead to stopping them forming stars abruptly when the rest of the universe doing so.”

Associate Professor Claudia Lagos from The University of Western Australia node of the International Centre for Radio Astronomy Research (ICRAR) was crucial in developing the theoretical modeling of the evolution of dark matter concentrations for the study.

“Galaxy formation is in large part dictated by how dark matter concentrates,” she says. “Having these extremely massive galaxies so early in the universe is posing significant challenges to our standard model of cosmology. This is because we don’t think such massive dark matter structures as to host these massive galaxies have had time yet to form. More observations are needed to understand how common these galaxies may be and to help us understand how truly massive these galaxies are.”

Glazebrook hopes this could be a new opening for our understanding of the physics of dark matter, stating, “JWST has been finding increasing evidence for massive galaxies forming early in time. This result sets a new record for this phenomenon. Although it is very striking, it is only one object. But we hope to find more, and if we do, this will really upset our ideas of galaxy formation.”

by Breck Carter   , Swinburne University of Technology

University of Michigan researchers are celebrating their discovery of a new plant biochemistry and its unusual ability to form cyclic peptides—molecules that hold promise in pharmaceuticals as they can bind to challenging drug targets.

Cyclic peptides are an emerging and promising area of drug research.

The new study, led by U-M College of Pharmacy researchers Lisa Mydy and Roland Kersten, revealed a mechanism by which plants generate cyclic peptides. The research is published in the journal Nature Chemical Biology.

Mydy identified the new plant protein fold and its novel chemistry, which she said had never been seen before. The protein can generate cyclic peptides, one of which holds potential as an anti-cancer drug.

“It’s extremely exciting,” said Mydy, a postdoctoral research fellow in the Department of Medicinal Chemistry. “This type of discovery doesn’t happen too often.”

Mydy and colleagues studied the biosynthesis of a class of macrocyclic peptides found in plants and known for their potential use as therapeutic drugs. They identified a “fascinating new protein fold that has a really unusual mechanism to form cyclic peptides. It is a new biochemistry that we have not seen before,” Mydy said.

The researchers also examined peptide cyclase, a protein called AhyBURP found in the roots of the peanut plant, a representative of the founding Unknown Seed Protein, or USP-type, which in turn is part of the BURP-domain protein family.

“There was no experimental information on our protein AhyBURP,” Mydy said. “The only hint we had for function was that the protein needed copper to cyclize a peptide.”

The research team studied the protein structures with X-ray crystallography and used the Advanced Photon Source at Argonne National Laboratory. In the process, they found that the “protein AhyBURP uses copper and oxygen in a unique way that we’re still investigating,” Mydy said.

“Most cyclic peptides need another enzyme to come in and do the cyclization chemistry,” she said. “However, AhyBURP can do it within the same protein on itself. Other copper-dependent proteins function by attaching oxygen somewhere on the peptide. We don’t observe that, and we want to know why. I see this as the first example of this type of chemistry that can happen with copper and oxygen within a protein.”

The discovery of the new protein grew from ongoing work in Kersten’s lab. As part of the U-M Natural Product Discovery Initiative, the Kersten lab aims to discover and research new plant-based chemicals that can become drugs and ultimately cure human diseases.

“We use a modern approach where we screen the genetic sequences of plants, searching for genes connected to new chemistry,” said Kersten, assistant professor of medicinal chemistry at the College of Pharmacy. “That’s how we identified the cyclic peptide products and their underlying proteins as a target of interest.”

This class of peptides is of interest because their cyclization properties make them more structured and stable, increasing their potential to be used as drugs.

Many drugs, including chemicals derived from living organisms, are cyclic, meaning that they can bind drug targets and remain intact in a patient for a desired time. Nature has evolved many biochemical solutions to produce such cyclic molecules.

Kersten has isolated other compounds made by the same protein family that have been shown to have suppressing effects on lung cancer cells in lab tests, so there is growing hope that this discovery will have potential as a future anti-cancer agent.

“Now that we know what the protein looks like for one of the BURP-domain proteins, we can test more ideas about how the protein may influence the chemical reaction between the peptide, copper and oxygen to form cyclic peptides,” said Mydy, a structural biologist and enzymologist by training.

“It is a fantastic and challenging puzzle to figure out why this is happening and understand the structure. It’s extremely exciting to be part of this type of discovery that may eventually lead to effective pharmaceutical therapeutics.”

A team including University of Wyoming anthropologists works at the site of a circular plaza that was built around 4,750 years ago in the Cajamarca Basin of northern Peru.

Two University of Wyoming anthropology professors have discovered one of the earliest circular plazas in Andean South America, showcasing monumental megalithic architecture, which refers to construction that uses large stones placed upright with no mortar.

Located at the Callacpuma archaeological site in the Cajamarca Basin of northern Peru, the plaza is built with large, vertically placed megalithic stones—a construction method previously unseen in the Andes. Associate Professor Jason Toohey, project lead, and Professor Melissa Murphy have been researching this topic since the project’s inception in 2015. Excavations took place in the plaza starting in 2018.

Their paper, which reports new data on this earliest known megalithic circular plaza in the northern Andes, is titled “A Monumental Stone Plaza at 4750 BP in the Cajamarca Valley of Peru” and has been published in Science Advances.

Radiocarbon dating places its initial construction around 4,750 years ago during the Late Preceramic Period, making it one of the earliest instances of such architecture in the Americas.

To better understand this timeline, the team carefully excavated within the plaza, uncovering artifacts related to life in the past and collecting charcoal samples for dating. All material remains then were cleaned, processed and analyzed in the laboratory.

“This structure was built approximately 100 years before the Great Pyramids of Egypt and around the same time as Stonehenge,” Toohey says.

These dates signify that the circular plaza at Callacpuma is the earliest known example of monumental and megalithic architecture in the Cajamarca Valley—and one of the earliest examples in ancient Peru.

“It was probably a gathering place and ceremonial location for some of the earliest people living in this part of the Cajamarca Valley,” Toohey adds. “These people were living a primarily hunting-and-gathering lifestyle and probably had only recently begun growing crops and domesticating animals.”

The plaza is formed by two concentric walls and measures about 60 feet in diameter.

The project is led by Toohey and Patricia Chirinos Ogata from the University of California-Santa Barbara. The team also includes Murphy, as well as undergraduate and graduate students from Peru and the U.S.

Toohey is an anthropological archaeologist who is dedicated to taking a holistic and multidisciplinary approach to the field. He has conducted fieldwork in the Peruvian Andes since 2003. The department head for anthropology at UW, Murphy is a biological anthropologist specializing in bioarchaeology and committed to multidisciplinary approaches within anthropology.

“As part of our community outreach, we collaborate and work with the residents of the towns on and adjacent to the site of Callacpuma about our findings and their importance,” Toohey says. “We highlight the importance of cultural heritage, and working together, we can continue the scientific investigations and help to preserve the site.”