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Mirror life is a scientific fantasy leading to a dangerous reality − a synthetic biologist explains how mirror bacteria could conquer life on Earth

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theconversation.com – Kate Adamala, Assistant Professor of Genetics, Cell Biology and Development, University of Minnesota – 2025-02-11 07:46:00

Mirror life is a scientific fantasy leading to a dangerous reality − a synthetic biologist explains how mirror bacteria could conquer life on Earth

Synthetic biology offers many tantalizing possibilities, but scientists consider some projects too risky to pursue.
DBenitostock/Moment via Getty Images

Kate Adamala, University of Minnesota

Most major biological molecules, including all proteins, DNA and RNA, point in one direction or another. In other words, they are chiral, or handed. Like how your left glove fits only your left hand and your right glove your right hand, chiral molecules can interact only with other molecules of compatible handedness.

Two chiralities are possible: left and right, formally called L for the Latin laevus and D for dexter. All life on Earth uses L proteins and D sugars. Even Archaea, a large group of microorganisms with unusual chemical compositions, stick to the program on the handedness of the main molecules they use.

For a long time, scientists have been speculating about making biopolymers that would mirror compounds in nature but in the opposite orientation – namely, compounds made of D proteins and L sugars. Recent years have seen some promising advancements, including enzymes that can make mirror RNAs and mirror DNAs.

Diagam of two molecular models that are mirror images of each other, like the two hands they're superimposed on
Chirality refers to something that is not superimposable on its mirror image – like your hands.
NASA

When scientists observed that these mirror molecules behave just like their natural equivalents they considered that it would be possible to make a whole living cell from them. Mirror bacteria in particular had the potential to be a useful basic research tool – possibly allowing scientists to study a new tree of life for the first time and solve many problems in bioengineering and biomedicine.

This so-called mirror life – living cells made from building blocks with an opposite chirality to those that make up natural life – could have very similar properties to natural living cells. They could live in the same environment, compete for resources and behave like you would expect of any living organism. They would be able to evade infection from other predators and immune systems because these opponents wouldn’t be able to recognize them.

These features are why researchers like me were so attracted to mirror life in the first place. But these qualities are also huge bugs of this technology that make it a problem.

I am a synthetic biologist who studies using chemistry to create living cells. I am also a bioengineer who develops tools for the bioeconomy. As a chemist by training, engineering mirror life initially seemed like a fascinating way to answer foundational questions about biology and practically apply those findings to industry and medicine. As I learned more about the immunology and ecology of mirror life, however, I became aware of the potential environmental and health consequences of this technology.

Real concerns about hypothetical mirror life

It’s important to note that researchers are likely at least 10 to 30 years away from creating mirror bacteria. On the timescale of a fast-moving field like synthetic biology, a decade is a very long time. Creating synthetic cells is difficult on its own. Creating mirrored ones would require several technical breakthroughs.

However, it would come with a risk. If mirror cells were released into the environment, they would likely be able to quickly proliferate without much restriction. The natural mechanisms that keep ecosystems in balance, including infection and predation, would not work on mirror life.

Bacteria, like most life forms, are susceptible to viral infections. These bacterial viruses, or bacteriophages, enter bacteria by binding to their surface receptors and then use their cellular machinery to replicate. But just as a left glove doesn’t fit a right hand, natural bacteriophages wouldn’t recognize mirror cell receptors or be able to use its machinery. Mirror life would likely be resistant to viruses.

Microscopy image of many geometric balls attached to a translucent sphere by thin strands
Mirror bacteria may be able to evade the bacteriophages that would otherwise help keep them in check. Here, multiple bacteriophages are attached to a bacterial cell wall.
Professor Graham Beards/Wikimedia Commons, CC BY-SA

Microorganisms foraging in the environment also keep bacterial populations in check. They differentiate food from nonfood by using chemical “taste” receptors. Anything those receptors bind to, such as bacteria and organic debris, are considered edible, while things that cannot bind to those receptors, such as rocks, are classified as inedible. Think about how a dog foraging on the kitchen floor will eat a bread roll but only sniff a spoon and move on. Mirror life would be, to the bacterial predators, more like a spoon than bread – predators would “sniff” it with their receptors and move on because these cells can’t bind.

Safety from being eaten would be great news for mirror bacteria, because it would allow it to replicate freely. It would be much worse news to the rest of the ecosystem, because mirror bacteria might hog all the nutrients and spread uncontrollably. Even if mirror bacteria don’t actively attack other organisms, they would still consume food sources other organisms need. And since mirror cells would have much lower death rates than regular organisms due to a lack of predation, they would slowly but surely take over the environment.

Even if mirror cells grow more slowly than normal cells, they would be able to grow without anything stopping them.

Insufficient immunity

Another biological control mechanism that wouldn’t be able to “sniff” out mirror cells is the immune system.

Your immune cells constantly check everything they find in your blood. The decision tree of an immune cell is fairly simple. First, decide whether something is alive or not, then compare it with its database of “self” – your own cells. If it is alive but is not a part of you, then it needs to be killed. Mirror cells likely wouldn’t pass the first step of that screen: it would not induce an immune response because the immune system would not be able to recognize or bind to mirror cell antigens. This means mirror cells could infect an unprecedentedly wide variety of hosts.

You might think an infection from mirror bacteria could be treated with antibiotics of the same handedness. It would probably work, and may even be easier on your gut than regular antibiotic therapy. Because antibiotics are also handed, mirror versions of these drugs would not affect your gut microbiome, just like how regular antibioics would not affect mirror cells.

But humans are a relatively small part of the ecosystem. All other animals and plants may also be susceptible to infection from mirror pathogens. While it is possible to imagine developing mirror antibiotics to treat human infections, it is physically impossible to treat the entire plant and animal world. If all organisms are susceptible to even a slow-moving infection by mirror bacteria, there is no good treatment that could be deployed across the entire ecosystem.

Better safe than sorry

Mirror life is an exciting research subject and a potential tool with some practical applications in medicine and biotechnology. But for many scientists, including me, none of those benefits outweigh the serious consequences to human health and the environment that mirror life poses.

I and a group of researchers in immunology, ecology, biosafety and security – including some who used to actively work on mirror life – conducted a thorough analysis of possible concerns regarding the creation of mirror life. No matter how we looked at it, straight up or in the mirror, the conclusions were clear: The potential benefits of engineering mirror life are not worth the risk.

YouTube video
Mirror life is scientifically tantalizing but ethically unwise.

There is no way to make anything completely foolproof, and that includes any safeguards built into a mirror cell that could prevent the risk of accidental or deliberate release into the environment. Researchers working in this space, including us, may find this disappointing. But not making mirror cells can ensure the safety and security of the planet. More discussion among the global scientific community about what kinds of research on mirror biomolecules and related technologies are safe – as well as how to regulate this research – can help safeguard against potential harms.

Keeping mirror cells inside the mirror, rather than making them a physical reality, is the clearest path to staying safe.The Conversation

Kate Adamala, Assistant Professor of Genetics, Cell Biology and Development, University of Minnesota

This article is republished from The Conversation under a Creative Commons license. Read the original article.

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A brief history of Medicaid and America’s long struggle to establish a health care safety net

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theconversation.com – Ben Zdencanovic, Postdoctoral Associate in History and Policy, University of California, Los Angeles – 2025-03-18 07:53:00

President Lyndon B. Johnson, left, next to former President Harry S. Truman, signs into law the measure creating Medicare and Medicaid in 1965.
AP Photo

Ben Zdencanovic, University of California, Los Angeles

The Medicaid system has emerged as an early target of the Trump administration’s campaign to slash federal spending. A joint federal and state program, Medicaid provides health insurance coverage for more than 72 million people, including low-income Americans and their children and people with disabilities. It also helps foot the bill for long-term care for older people.

In late February 2025, House Republicans advanced a budget proposal that would potentially cut US$880 billion from Medicaid over 10 years. President Donald Trump has backed that House budget despite repeatedly vowing on the campaign trail and during his team’s transition that Medicaid cuts were off the table.

Medicaid covers one-fifth of all Americans at an annual cost that coincidentally also totals about $880 billion, $600 billion of which is funded by the federal government. Economists and public health experts have argued that big Medicaid cuts would lead to fewer Americans getting the health care they need and further strain the low-income families’ finances.

As a historian of social policy, I recently led a team that produced the first comprehensive historical overview of Medi-Cal, California’s statewide Medicaid system. Like the broader Medicaid program, Medi-Cal emerged as a compromise after Democrats failed to achieve their goal of establishing universal health care in the 1930s and 1940s.

Instead, the United States developed its current fragmented health care system, with employer-provided health insurance covering most working-age adults, Medicare covering older Americans, and Medicaid as a safety net for at least some of those left out.

Health care reformers vs. the AMA

Medicaid’s history officially began in 1965, when President Lyndon B. Johnson signed the system into law, along with Medicare. But the seeds for this program were planted in the 1930s and 1940s. When President Franklin D. Roosevelt’s administration was implementing its New Deal agenda in the 1930s, many of his advisers hoped to include a national health insurance system as part of the planned Social Security program.

Those efforts failed after a heated debate. The 1935 Social Security Act created the old-age and unemployment insurance systems we have today, with no provisions for health care coverage.

Nevertheless, during and after World War II, liberals and labor unions backed a bill that would have added a health insurance program into Social Security.

Harry Truman assumed the presidency after Roosevelt’s death in 1945. He enthusiastically embraced that legislation, which evolved into the “Truman Plan.” The American Medical Association, a trade group representing most of the nation’s doctors, feared heightened regulation and government control over the medical profession. It lobbied against any form of public health insurance.

YouTube video
This PBS ‘Origin of Everything!’ video sums up how the U.S. wound up with its complex health care system.

During the late 1940s, the AMA poured millions of dollars into a political advertising campaign to defeat Truman’s plan. Instead of mandatory government health insurance, the AMA supported voluntary, private health insurance plans. Private plans such as those offered by Kaiser Permanente had become increasingly popular in the 1940s in the absence of a universal system. Labor unions began to demand them in collective bargaining agreements.

The AMA insisted that these private, employer-provided plans were the “American way,” as opposed to the “compulsion” of a health insurance system operated by the federal government. They referred to universal health care as “socialized medicine” in widely distributed radio commercials and print ads.

In the anticommunist climate of the late 1940s, these tactics proved highly successful at eroding public support for government-provided health care. Efforts to create a system that would have provided everyone with health insurance were soundly defeated by 1950.

JFK and LBJ

Private health insurance plans grew more common throughout the 1950s.

Federal tax incentives, as well as a desire to maintain the loyalty of their professional and blue-collar workers alike, spurred companies and other employers to offer private health insurance as a standard benefit. Healthy, working-age, employed adults – most of whom were white men – increasingly gained private coverage. So did their families, in many cases.

Everyone else – people with low incomes, those who weren’t working and people over 65 – had few options for health care coverage. Then, as now, Americans without private health insurance tended to have more health problems than those who had it, meaning that they also needed more of the health care they struggled to afford.

But this also made them risky and unprofitable for private insurance companies, which typically charged them high premiums or more often declined to cover them at all.

Health care activists saw an opportunity. Veteran health care reformers such as Wilbur Cohen of the Social Security Administration, having lost the battle for universal coverage, envisioned a narrower program of government-funded health care for people over 65 and those with low incomes. Cohen and other reformers reasoned that if these populations could get coverage in a government-provided health insurance program, it might serve as a step toward an eventual universal health care system.

While President John F. Kennedy endorsed these plans, they would not be enacted until Johnson was sworn in following JFK’s assassination. In 1965, Johnson signed a landmark health care bill into law under the umbrella of his “Great Society” agenda, which also included antipoverty programs and civil rights legislation.

That law created Medicare and Medicaid.

From Reagan to Trump

As Medicaid enrollment grew throughout the 1970s and 1980s, conservatives increasingly conflated the program with the stigma of what they dismissed as unearned “welfare.” In the 1970s, California Gov. Ronald Reagan developed his national reputation as a leading figure in the conservative movement in part through his high-profile attempts to cut and privatize Medicaid services in his state.

Upon assuming the presidency in the early 1980s, Reagan slashed federal funding for Medicaid by 18%. The cuts resulted in some 600,000 people who depended on Medicaid suddenly losing their coverage, often with dire consequences.

Medicaid spending has since grown, but the program has been a source of partisan debate ever since.

In the 1990s and 2000s, Republicans attempted to change how Medicaid was funded. Instead of having the federal government match what states were spending at different levels that were based on what the states needed, they proposed a block grant system. That is, the federal government would have contributed a fixed amount to a state’s Medicaid budget, making it easier to constrain the program’s costs and potentially limiting how much health care it could fund.

These efforts failed, but Trump reintroduced that idea during his first term. And block grants are among the ideas House Republicans have floated since Trump’s second term began to achieve the spending cuts they seek.

Women carry boxes labeled 'We need Medicaid for Long Term Care' and We need Medicaid for Pediatric Care' at a protest in 2017.
Protesters in New York City object to Medicaid cuts sought by the first Trump administration in 2017.
Erik McGregor/LightRocket via Getty Images

The ACA’s expansion

The 2010 Affordable Care Act greatly expanded the Medicaid program by extending its coverage to adults with incomes at or below 138% of the federal poverty line. All but 10 states have joined the Medicaid expansion, which a U.S. Supreme Court ruling made optional.

As of 2023, Medicaid was the country’s largest source of public health insurance, making up 18% of health care expenditures and over half of all spending on long-term care. Medicaid covers nearly 4 in 10 children and 80% of children who live in poverty. Medicaid is a particularly crucial source of coverage for people of color and pregnant women. It also helps pay for low-income people who need skilled nursing and round-the-clock care to live in nursing homes.

In the absence of a universal health care system, Medicaid fills many of the gaps left by private insurance policies for millions of Americans. From Medi-Cal in California to Husky Health in Connecticut, Medicaid is a crucial pillar of the health care system. This makes the proposed House cuts easier said than done.The Conversation

Ben Zdencanovic, Postdoctoral Associate in History and Policy, University of California, Los Angeles

This article is republished from The Conversation under a Creative Commons license. Read the original article.

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People say they prefer stories written by humans over AI-generated works, yet new study suggests that’s not quite true

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theconversation.com – Martin Abel, Assistant Professor of Economics, Bowdoin College – 2025-03-18 07:52:00

Artificial intelligence is expected to generate a growing share of the world’s creative work.
karetoria/Moment via Getty Images

Martin Abel, Bowdoin College and Reed Johnson, Bowdoin College

People say they prefer a short story written by a human over one composed by artificial intelligence, yet most still invest the same amount of time and money reading both stories regardless of whether it is labeled as AI-generated.

That was the main finding of a study we conducted recently to test whether this preference of humans over AI in creative works actually translates into consumer behavior. Amid the coming avalanche of AI-generated work, it is a question of real livelihoods for the millions of people worldwide employed in creative industries.

To investigate, we asked OpenAI’s ChatGPT 4 to generate a short story in the style of the critically acclaimed fiction author Jason Brown. We then recruited a nationally representative sample of over 650 people and offered participants US$3.50 to read and assess the AI-generated story. Crucially, only half the participants were told that the story was written by AI, while the other half was misled into believing it was the work of Jason Brown.

After reading the first half of the AI-generated story, participants were asked to rate the quality of the work along various dimensions, such as whether they found it predictable, emotionally engaging, evocative and so on. We also measured participants’ willingness to pay in order to read to the end of the story in two ways: how much of their study compensation they’d be willing to give up, and how much time they’d agree to spend transcribing some text we gave them.

So, were there differences between the two groups? The short answer: yes. But a closer analysis reveals some startling results.

To begin with, the group that knew the story was AI-generated had a much more negative assessment of the work, rating it more harshly on dimensions like predictability, authenticity and how evocative it is. These results are largely in keeping with a nascent but growing body of research that shows bias against AI in areas like visual art, music and poetry.

Nonetheless, participants were ready to spend the same amount of money and time to finish reading the story whether or not it was labeled as AI. Participants also did not spend less time on average actually reading the AI-labeled story.

When asked afterward, almost 40% of participants said they would have paid less if the same story was written by AI versus a human, highlighting that many are not aware of the discrepancies between their subjective assessments and actual choices.

Why it matters

Our findings challenge past studies showing people favor human-produced works over AI-generated ones. At the very least, this research doesn’t appear to be a reliable indicator of people’s willingness to pay for human-created art.

The potential implications for the future of human-created work are profound, especially in market conditions in which AI-generated work can be orders of magnitude cheaper to produce.

Even though artificial intelligence is still in its infancy, AI-made books are already flooding the market, recently prompting the authors guild to instate its own labeling guidelines.

Our research raises questions whether these labels are effective in stemming the tide.

What’s next

Attitudes toward AI are still forming. Future research could investigate whether there will be a backlash against AI-generated creative works, especially if people witness mass layoffs. After all, similar shifts occurred in the wake of mass industrialization, such as the arts and crafts movement in the late 19th century, which emerged as a response to the growing automation of labor.

A related question is whether the market will segment, where some consumers will be willing to pay more based on the process of creation, while others may be interested only in the product.

Regardless of how these scenarios play out, our findings indicate that the road ahead for human creative labor might be more uphill than previous research suggested. At the very least, while consumers may hold beliefs about the intrinsic value of human labor, many seem unwilling to put their money where their beliefs are.

The Research Brief is a short take about interesting academic work.The Conversation

Martin Abel, Assistant Professor of Economics, Bowdoin College and Reed Johnson, Senior Lecturer in Russian, East European and Eurasian Studies, Bowdoin College

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Cells lining your skin and organs can generate electricity when injured − potentially opening new doors to treating wounds

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theconversation.com – Sun-Min Yu, Postdoctoral Research Fellow in Polymer Science and Engineering, UMass Amherst – 2025-03-17 14:47:00

Your skin cells can generate electricity when wounded.
Torsten Wittmann, University of California, San Francisco/NIH via Flickr, CC BY-NC

Sun-Min Yu, UMass Amherst and Steve Granick, UMass Amherst

Your cells constantly generate and conduct electricity that runs through your body to perform various functions. One such example of this bioelectricity is the nerve signals that power thoughts in your brain. Others include the cardiac signals that control the beating of your heart, along with other signals that tell your muscles to contract.

As bioengineers, we became interested in the epithelial cells that make up human skin and the outer layer of people’s intestinal tissues. These cells aren’t known to be able to generate bioelectricity. Textbooks state that they primarily act as a barrier against pathogens and poisons; epithelial cells are thought to do their jobs passively, like how plastic wrapping protects food against spoilage.

To our surprise, however, we found that wounded epithelial cells can propagate electrical signals across dozens of cells that persist for several hours. In this newly published research, we were able to show that even epithelial cells use bioelectricity to coordinate with their neighbors when the emergency of an injury demands it. Understanding this unexpected twist in how the body operates may lead to improved treatments for wounds.

Discovering a new source of bioelectricity

Don’t laugh: Our interest in this topic began with a gut feeling. Think of how your skin heals itself after a scratch. Epithelial cells may look silent and calm, but they’re busy coordinating with each other to extrude damaged cells and replace them with new ones. We thought bioelectric signals might orchestrate this, so our intuition told us to search for them.

Almost all the vendors we contacted to obtain the instrument we needed to test our idea warned us not to try these experiments. Only one company agreed with reluctance. “Your experiment won’t work,” they insisted. If we made the attempt and found nothing worthwhile to study, they feared it would make their product look bad.

But we did our experiments anyway – with tantalizing results.

We grew a layer of epithelial cells on a chip patterned with what’s called a microelectrode array – dozens of tiny electric wires that measure where bioelectric signals appear, how strong the signals are and how fast they travel from spot to spot. Then, we used a laser to zap a wound in one location and searched for electric signals on a different part of the cell layer.

Close-up of a person's hand stretching a gel-like material with an array of metal strips radiating from the center towards the edges
Microelectrode arrays detect electrical signals in cells.
Kwayyy/Wikimedia Commons, CC BY-SA

Several hours of recording confirmed our intuition: When faced with the emergency need to repair themselves, bioelectrical signals appear when epithelial cells need a quick way to communicate over long distances.

We found that wounded epithelial cells can send bioelectric signals to neighboring cells over distances more than 40 times their body length with voltages similar to those of neurons. The shapes of these voltage spikes are also like those of neurons except about 1,000 times slower, indicating they might be a more primitive form of intercellular communication over long distances.

Powering the bioelectric generator

But how do epithelial cells generate bioelectricity?

We hypothesized that calcium ions might play a key role. Calcium ions show up prominently in any good biology textbook’s list of major molecules that help cells function. Since calcium ions regulate the forces that contract cells, a function necessary to remove damaged cells after wounding, we hypothesized that calcium ions ought to be critical to bioelectricity.

To test our theory, we used a molecule called EDTA that tightly binds to calcium ions. When we added EDTA to the epithelial cells and so removed the calcium ions, we found that the voltage spikes were no longer present. This meant that calcium ions were likely necessary for epithelial cells to generate the bioelectric signals that guide wound healing.

We then blocked the ion channels that allow calcium and other positively charged ions to enter epithelial cells. As a result, the frequency and strength of the electrical signals that epithelial cells produce were reduced. These findings suggest that while calcium ions may play a particularly crucial role in allowing epithelial cells to produce bioelectricity, other molecules may also matter.

Further research can help identify those other ion channels and pathways that allow epithelial cells to generate bioelectricity.

Microscopy image of human large intestine tissue, which appears as two curved arms layered with fringe
Epithelial cells line your large intestine.
Choksawatdikorn/Science Photo Library via Getty Images

Improving wound healing

Our discovery that epithelial cells can electrically speak up during a crisis without compromising their primary role as a barrier opens doors for new ways to treat wounds.

Previous work from other researchers had demonstrated that it’s possible to enhance wound healing in skin and intestinal tissues by electrically stimulating them. But these studies used electrical frequencies many times higher than what we’ve found epithelial cells naturally produce. We wonder whether reevaluating and refining optimal electric stimulation conditions may help improve biomedical devices for wound healing.

Further down the road of possibility, we wonder whether electrically stimulating individual cells might offer even more healing potential. Currently, researchers have been electrically stimulating the whole tissue to treat injury. If we could direct these electrical signals to go specifically to where a remedy is needed, would stimulating individual cells be even more effective at treating wounds?

Our hope is that these findings could become a classic case of curiosity-driven science that leads to useful discovery. While our dream may carry a high risk of failure, it also offers potentially high rewards.The Conversation

Sun-Min Yu, Postdoctoral Research Fellow in Polymer Science and Engineering, UMass Amherst and Steve Granick, Professor of Polymer Science and Engineering, UMass Amherst

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