6.19.25

Episode Transcript

Speaker 1 (00:01):
Welcome to Radiowized Diary of Science and Nature, Your readers,
Kelly Taylor. We'll have some articles related to science and nature,
but first a reminder. RADIOI is a reading service intended
for people who are blind or have other disabilities that
make it difficult to read prinum material. Starting off today
with an article from Popular Science dated June sixteenth, What's

(00:24):
the purpose of dreaming? We all dream? But why? As
with many mysteries of the mind, science doesn't have one
neat answer. You'll get as many answers to the question
what is the purpose of dreaming? As there are dream psychologists,
says Deirdre Barrett, dream researcher at Harvard University and author

(00:47):
of the Committee of Sleep. According to Austrian neurologist and
founder of psychoanalysis, Sigmund Freud, dreams offered vital clues to
unresolved conflict buried deep within our psyche. But Freud's theory,
introduced in his eighteen ninety nine book The Interpretation of Dreams,

(01:09):
sparked plenty of controversy. Critics argued that his dream interpretations
were overly focused on sex, highly subjective, and impossible to verify.
Two analysts might offer entirely different readings of the same dream,
with no objective way to know who was right. In
the decades since Freud, other scientists have offered alternative explanations

(01:32):
for why we dream. One of the most prominent is
the threat stimulation I'm sorry threat simulation theory, proposed by
Finnish neuroscientist and psychologist Anti Ravonsuo in two thousand. According
to this view, dreaming is an ancient biological defense mechanism.

(01:54):
By simulating dangerous situations, our brains rehearse the skills needed
to recognize and avoid threats, a kind of virtual reality
training ground for survival. A two thousand and five study
lent support to this theory by examining the dreams of
Kurdish children exposed to war and trauma compared to non

(02:17):
traumatized Finnish children. These children reported more frequent dreams filled
with severe threats, suggesting that their minds were practicing how
to cope with danger. But even the threat simulation theory
is debated. A two thousand and eight study comparing residents
of high crime areas in South Africa to those in
low crime parts of Wales found that South African participants,

(02:41):
despite facing more real world threats actually reported fewer threatening
dreams than their Welsh counterparts. This result challenges the idea
that the brain uses dreams to simulate danger when exposed
to trauma. Another theory suggests that dreams are simply a
side effect of memory consolidation, the brain's way of replaying

(03:05):
and reinforcing new memories while we sleep. As the brain's
hippocampus and neocortex worked together to file away fresh information,
they may also blend it with older memories, creating the
often strange mash ups we experience as dreams. Dreams may
also help us process and manage emotions, especially negative ones,

(03:27):
according to the emotion regulation theory of dreaming. Research focusing
on recently divorced individuals experiencing depression found that participants who
dreamed about their ex spouses were more likely to show
significant improvement in their mood one year later, particularly if
their dreams were vivid and emotionally rich. Another study found

(03:51):
that people who dreamed about stressful events they had experienced
before sleep woke up feeling more positively about the events
the next day, Such as that dreams can help transform
emotional distress into resilience. Recent brain imaging studies support this idea.
People who frequently experience fear related dreams show reduced activation

(04:15):
in fear centers of the brain during waking life, hinting
that these dreams may serve as a kind of overnight
therapy session, helping us better regulate our emotions when awake. Ultimately,
Barrett suggests that we may be asking the wrong question.
Quote we'd rarely ask the analogis question what is the

(04:36):
purpose of thinking? She says, just as waking thought serves
many functions, from planning to problem solving to daydreaming, dreams
likely do too. Quote. The value of dreaming lies in
its difference. It's a distinct mode of thought, one that
supplements and enriches our waking cognition. In fact, some researchers

(05:03):
believe dreams offer a unique mental space for solving problems
that stump us during the day. In this altered brain state,
regions responsible for imagery become more active, allowing a mind
to solve problems requiring visualization. History is full of famous examples.
Mary Shelley reportedly dreamed the central scenes of Frankenstein. German

(05:28):
chemist Auguste Kekule envisioned the ring structure of Benzene in
a dream, and Russian chemist Dmitri Mendeleev dreamed his final
form of the periodic table of the elements. In the end,
dreams may serve many purposes or none at all, but
they remind us that even in sleep, the brain never

(05:48):
truly rests. And now we go to Wired Magazine. This
article's headline Scientists discover the key to Axelottel's ability to
reach generate limbs written by Anna Legos and dated June seventeen.
The axe Lotel seems like something out of science fiction.

(06:11):
This perpetually youthful looking Mexican salamander possesses a superpower that
defies biology as we know it, the ability to regenerate
entire limbs, parts of its heart, and even its spinal cord.
But how does an amputated limb know whether to regenerate
an entire arm from the shoulder down or just a

(06:33):
hand from the wrist. This mystery of positional identity has
fascinated scientists for decades. A team at Northeastern University led
by James Monaghan has unraveled a key piece of this
biological puzzle in a study published in Nature Communications. The
researchers reveal an elegant molecular mechanism that acts like a

(06:57):
GPS coordinate system for regenerating cells. Surprisingly, the secret lab
is not in producing more of a chemical signal, but
in how quickly it is destroyed. Monahan's lab houses about
five hundred acxiltels, cared for by a team ranging from

(07:18):
undergraduate students to postdocs. Quote Raising acxi lottels involves managing
a complex aquatic system and being patient as they reach
sexual maturity within a year. It's slower than with other
model organisms, but also more exciting. In many experiments, the
team is exploring completely new terrain, Monaghan says. For more

(07:41):
than two decades, Monahan's lab has been studying the axe
lottl to understand how it regenerates complex organs such as
its limbs, vital cord, heart, and tail. His lab's research
focuses on uncovering why nerves are essential to this process
and what unique cellular properties allow axilotels to regenerate tissues

(08:04):
that other animals cannot. These findings could transform our understanding
of bodily regeneration and have important applications in regenerative medicine.
For years we've known that retonoic acid, a derivative of
vitamin A, is a grit crucial molecule that screens to

(08:24):
cells mild a shoulder, explains Monahan. But the puzzle was
how the cells in the regenerating limb stump controlled their
levels so precisely to know exactly where they were on
the axis from shoulder to hand. To unpack this mystery,
the team focused on a cluster of stem cells that

(08:47):
form at the wound site after a limb is lost.
In animals like the axilotel that are capable of regeneration
known as the blasphema, it's this base of stem cells
that then orchestrates regeneration. The prevailing theory was that differences
in retinoic acid might explain why a shoulder a proximal

(09:11):
amputation leads to an entire limb being regenerated, while a
wrist a distal amputation only regenerates the hand. Our big
surprise was to discover that the key was not in
how much retinoic acid was produced, but in how it
was degraded, says Monahan. The team discovered that cells in

(09:32):
the distal part of the limb the risk are a
wash in an enzyme called CYP twenty six V one,
whose sole function is to destroy retinoic acid. In contrast,
cells in the shoulder have hardly any of this enzyme,
allowing retinoic acid to accumulate to high levels. This difference

(09:53):
creates a chemical gradient along the limb, lots of retinoic
acid in the shoulder little in the wrist. It is
this gradient that informs cells of their exact location. In humans,
this pathway of cellular plasticity is absent or closed. Therefore,
the great challenge is to understand how to induce this

(10:14):
blastomal state in our cells, a key transient structure in regeneration.
If achieved, it would be possible for our cells to
respond again to positional and regenerative signals as they do
in the axolotl, explains Monahan. To confirm their discovery, the

(10:35):
researchers conducted in experiment. They amputated axolotal legs at the
wrist and administered a drug called talosol, which inhibits the
CYP twenty six P one enzyme by turning off the
brakes on retinoic acid. It accumulated to extremely high levels
in a place where it normally shouldn't as a result

(10:57):
of wrist cells, confused by the high concentration of retinoic acid,
interpreted position as being the shoulder. Instead of regenerating a hand,
they proceeded to regenerate a complete, duplicated limb. It was
the ultimate test, Monahan says. The team went a step

(11:18):
further to identify which genes were activated by these high
levels of retinoic acid. They discovered a master gene that
was specifically activated in shoulder areas, shocks. SHOX, an abbreviation
of short stature homeobox gene. SHOX is so called because
mutations to it in humans cause short stature. We identified

(11:42):
SHOCKS as a critical instruction manual in this process. Monahan explains,
it's the gene that tells developing cells to build the
arm and forearm bones. To confirm this, the team used
Crisper gene editing technology to knock out the SHOCKS gene
in axalottal embryos. The resulting animals had had peculiar limbs,

(12:05):
normal size hands and fingers, but significantly shorter and underdeveloped
arms and forearms. This demonstrated that SHOCKS is essential for
shaping proximal but not distal structures, revealing that regeneration uses
distinct genetic programs for each limb segment. This study not
only solves a long standing mystery of regenerative biology, but

(12:29):
also provides a molecular roadmap. By understanding how the AXOLOTL
reads and executes its genetic instructions for regeneration, scientists can
begin to think about how someday we might learn to
write our own genetic instructions. The AXALOTL has cellular properties
that we want to understand at the deepest level, says Monahan.

(12:51):
While regeneration of a complete human limb is still in
the realm of science fiction, each time we discover a
piece of this genetic blueprint, such as the role of
CYP twenty six B one and shocks, we move one
step closer to understanding how to orchestrate complex tissue repair
in humans. To bring this science closer to clinical applications,

(13:14):
one crucial step is to succeed in inducing blas STEMA
formations of stem cells at sites of amputation in humans.
This is the holy grail of regenerative biology. Understanding the
minimal components that make it up the molecular signals a
cellular environment. The physiological conditions would allow us to transform

(13:36):
a scar into a regenerative tissue, explains Monihan. In his
current research, there are still gaps to be filled, how
the CYP twenty six B one gradient is regulated, how
retanoic acid connects to the shocks gene, and what downstream
factors determine the formation of specific structures such as the

(13:58):
humorous or radius moment. Monahan explains that axelotels do not
possess a magic gene for regeneration, but share the same
fundamental genes as humans. The key difference lies in the
accessibility of those genes. While an injury in humans activates
genes that induce scarring, in salamanders, there is cell d differentiation.

(14:23):
The cells return to an embryonic like state where they
can respond to signals such as retinoic acid. This ability
to return to a developmental state is the basis of
their regeneration, explains the researcher. So if humans have the
same genes, why can't we regenerate? The difference is that

(14:44):
the salamander can reaccess that developmental program after injury. Humans cannot.
They only access this development pathway during initial growth, before birth,
we've had selective pressure to shut down and heal. Monan says,
my dream and the community's dream, is to understand how
to make the transition from scar to blasphema. Monahan says

(15:08):
that in theory, it would not be necessary to modify
human DNA to induce regeneration, but to intervene at the
right time and place in the body with regulatory molecules.
For example, the molecular pathways that signal a cell to
be located in the elbow on the pinky side and
not the thumb could be reactivated in a regenerative environment

(15:31):
using technologies such as crisper. This understanding could be applied
in stem cell therapies. Currently, laboratory grown stem cells do
not know where they are when they are transplanted. If
they can be programmed with precise positional signals, they could
integrate properly into damaged tissues and contribute to structural regeneration,

(15:54):
such as forming a complete humorous says Monahan. After years work,
understanding the role of retinoic acid studied since nineteen eighty one,
is a source of deep satisfaction. From my hand. The
scientist imagines a future where a patch placed on a
wound can reactivate developmental programs in human cells, emulating the

(16:17):
regenerative mechanism of the salamander. Although not immediate, he believes
that SELL engineering to induce regeneration is a goal already
within the reach of science. He reflects on how the
axelotel has had a second scientific life. It was a

(16:38):
dominant model one hundred years ago, then fell into disuse
for decades, and now has re emerged thanks to modern
tools such as gene editing and SELL analysis. The team
can study any gene and SELL during the regenerative process.
And now from Popular Science, we have another article focusing

(17:02):
on the axolotl and this headline is axalottl mucous peptides
attack breast cancer cells and MRSA dated June seventeenth. Among
animals that can regrow their detached limbs, Mexico's axolotls stand out.
These endangered amphibians can also regrow organs, including parts of

(17:24):
its brain and heart. Now biologists are looking closer at
the mucus on these masters of regrowth. The antimicrobial peptides
AMP in the axolottl's mucous membranes protect them from pathogens. Now,
a new study believes that this Internet famous animal could
hold some solutions to antibiotic resistance. Its antimicrobial peptides were

(17:51):
effective against multi resistant bacteria, including the dreaded methicillin resistant
Staphylococcus aureus or and helped combat cancer cells. The results
are described in a study recently published in the journal
plos one. Antimicrobial peptides are among the most promising candidates

(18:14):
for tackling further antibiotic resistance. They are found in almost
all living organisms and are part of the innate immune system.
Antimicrobial peptides could be an alternative to antibiotics in the future.
Study co author doctor Peter Vote, surgeon and clinic director
at Kirsten Reimer's laboratory at the Clinic for Plastic Esthetic,

(18:38):
Hand and Reconstructive Surgery in Hanover, Germany. They have a
broad spectrum of activity and at the same time it
is more difficult for pathogens to develop resistance. Axelotels in
the wild are threatened with extinction largely due to habitat degradation, pollution,
and non native predators. In their small geographic range in

(18:59):
southern Mexico City, the Lakes and canals. The Ambistoma mexicanom
bio Regeneration Center is currently home to the axelotal species
Ambistoma mexicanom, among other amphibian species that scientists can examine.
All the animals in this study come from captive breeding.

(19:22):
To obtain skin mucus for his new study, the axilotels
were gently massaged with sterile gloves. The mucus produced by
the amphibians was removed from the gloves with steril scrapers.
According to the team, this work was done in accordance
with the guidelines of the German Animal Welfare Act. Out
of the thousands of antimicrobial peptides extracted, the team selected

(19:44):
twenty two likely effective peptide candidates. This is time consuming
and expensive, but unfortunately amps are not as easy to
produce in microorganisms as some antibiotics. Explained vote the chemical
structure and mechanism are what make them so difficult to produce.
They all contain amino acids with a positive charge and

(20:06):
have water repellent components so that they can bind to
the cell wall of bacteria. Once attached to the bacterial
cell wall, they either create small holes in it to
penetrate the cell or bind to molecules. Both processes damage
the cell and lead to death. Antimicrobial peptides can also

(20:27):
act against viruses and fungi. According to study co author
Sarah Straub, that special chemical structure could be what makes
antimicrobial peptides effective against resistant bacterial strains and might reduce
the risk of further resistance. Harnessing the power of that

(20:48):
chemical structure could yield a decisive advantage, since even reserve
antibiotics are at risk of losing efficacy against bacteria. Reserve
antibiotics are used for infections caused by bacteria when conventional
antibiotics are no longer effected. This is the case in MERSA,
which causes roughly twenty thousand infections per year in the US.

(21:12):
Four of the oxalotal antimicrobial peptides showed efficacy against MERSA.
In some cases, they were even more effective than the
reserve antibiotic. The results against MERSA are particularly significant because
the spread of this multi resistant bacterial strain will continue
to increase with the over use of antibiotics in both

(21:33):
health care and agriculture, said Vote. The team also detected
an anti carcinogenic effect in three of the four antimicrobio peptides.
This group also was effective against MERSA. In a cell culture,
these peptides triggered a program cell death in breast cancer cells.

(21:53):
Program cell death is a controlled biological program in which
the effected cell dies in a lab. We observe that
the peptide specifically kidle cancer cells without attacking healthy breast
tissue cells, Straub said. Overall, our results suggest that these
identified amps could be promising candidates for combating antimicrobic resistance

(22:16):
and for anti cancer strategies. While more studies are needed
to verify these results, they are a basis for additional
research into what future therapeutics are lurking in axelattle mucus.
Now we have an article from National Geographic what we
can learn from the genius of beavers. The East Troublesome

(22:38):
Fire erupted on October twenty first, twenty twenty. Whipped by
strong winds and fueled by drought parched forests, the fire
roared through northern Colorado's spruce and fir woods. It leaked
roads and rivers, and the Continental Divide, scaling mountain passes
above tree line. It incinerated historic buildings in Rocky Mountain

(22:59):
National Park and homes in Grand County, killing two people. Ultimately,
it torched nearly two hundred thousand acres, making it the
second largest fire in Colorado's history. In the end, just
about the only thing the East Troublesome didn't consume was
beaver ponds. This was not entirely surprising. Beavers, of course,

(23:21):
build dams that store water, and water, as you may know,
doesn't burn. But the benefit the semi aquatic rodents provide
goes further than that. In a study published weeks before
the East Troublesome blew up, Emily Fairfax and eco hydrologists
now at the University of Minnesota, found that beaver ponds

(23:42):
and canals irrigate the landscape so thoroughly that they turned crisp,
flammable pint plants into lush, fireproof ones, forming green refuges
in which wild life and livestock can retreat. In a
nod to another firefighting icon, Fairfax and her co author
titled their paper Smoky the Beaver. Fairfax studied five fires

(24:05):
between two thousand and twenty eighteen to reach her conclusions,
but the East Troublesome was far bigger than most of those.
Blazes and a harbinger of the kind of conflagration we're
seeing more and more. Although fire has long been a
natural force of regeneration on North American landscapes, the so
called mega fires that plague the ever drier West are

(24:27):
a different matter, stoked by climate change into explosive infernos
that can burn so big and hot that ecosystems don't
always readily recover. Fairfax doubted whether beavers could steal fireproof
large tracts of landscape under those conditions, but when she
visited the charred forests left behind by the East Troublesome

(24:48):
and one other megafire, she discovered that the oases beavers
created with their ponds had endured these. There are entire
rivers that are basically unaffected by the fire because it's
just beaver dams the whole way, she said, Everything is
full of life. The reeds are growing, the pine needles
are still on the trees. The ponds aren't merely helpful

(25:11):
before a fire. They can also protect ecosystems from the
effects that come right after a blaze, capturing the ash
and debris that run off illsalt hill slopes and shielding
downstream fish and drinking water. In a twenty twenty four
paper describing their findings, Fairfax and her collaborators concluded that

(25:31):
beaver's quote can be part of a comprehensive fire mitigation
strategy end quote. Once hunted to near extinction for their
pelts and later villainized as a nuisance, beavers have rebounded.
There are now ten to fifteen million swimming and waddling
across most of North America, and they're ready for their

(25:53):
third act. Cast in an improbable role. Ecological saviors to
a climate change ravaged war, and fire mitigation is just
the start. By building dams that slow stream flow, they
create reservoirs that help combat drought. By sculpting wetlands, they
furnish habitat for other animals. Nowhere is their return more

(26:18):
unnecessary than in the climate stressed American West, where beaver
restoration is unfolding to some extent in every state. But beavers,
tireless meddlers with a penchant for running a foul of
human infrastructure, aren't yet universally welcome. The sand Pedro River
snakes across Arizona's border with Mexico through the sun blasted

(26:41):
Sonoran Desert. Though the arid land seems better suited for
rattlesnakes than semi aquatic rodents. Frontiersmen once knew the San
Pedro as the Beaver River, before nineteenth century trappers stripped
it clean. Anywhere there were perennial waters, there were probably beavers,
says lisa's Speck, the director of a nonprofit called the

(27:04):
Watershed Management Group. In nineteen ninety nine, in hopes of
enhancing the area's wildlife habitat, the Bureau of Land Management
restocked the sand Priedro with sixteen beavers, whose offspring dispersed
throughout the river, including into Mexico. Since twenty twenty, Shepeck,
along with Mexican biologists and legions of volunteers, has been

(27:25):
scouring the river to estimate the population. Along the trunk
of one down cottonwood, beavers had chiseled away the bark
to expose hartwood and whittled limbs to blunt points. Pale
chips covered the banks. They were probably here within the
last few weeks, Shepeck half whispered, it's easy to emphas

(27:45):
empathize with beavers. Like many of us, they live in
nuclear families on land. Beavers are clumsy, morsels for cougars
and wolves and bears, but they are very good swimmers,
endowed with transparent eyelids and webbed hind feet. Well that's
all for today's Diary of Science and Nature. The reader
is Kelly Taylor. Now stay tuned for the Health Core

(28:08):
on RADIOI