Transcript

6.19.25 · Science Show KY

0:01
Speaker 1: Welcome to Radiowized Diary of Science and Nature, Your readers,
0:04
Kelly Taylor. We'll have some articles related to science and nature,
0:08
but first a reminder. RADIOI is a reading service intended
0:13
for people who are blind or have other disabilities that
0:16
make it difficult to read prinum material. Starting off today
0:20
with an article from Popular Science dated June sixteenth, What's
0:24
the purpose of dreaming? We all dream? But why? As
0:29
with many mysteries of the mind, science doesn't have one
0:33
neat answer. You'll get as many answers to the question
0:37
what is the purpose of dreaming? As there are dream psychologists,
0:42
says Deirdre Barrett, dream researcher at Harvard University and author
0:47
of the Committee of Sleep. According to Austrian neurologist and
0:53
founder of psychoanalysis, Sigmund Freud, dreams offered vital clues to
0:59
unresolved conflict buried deep within our psyche. But Freud's theory,
1:03
introduced in his eighteen ninety nine book The Interpretation of Dreams,
1:09
sparked plenty of controversy. Critics argued that his dream interpretations
1:13
were overly focused on sex, highly subjective, and impossible to verify.
1:19
Two analysts might offer entirely different readings of the same dream,
1:23
with no objective way to know who was right. In
1:28
the decades since Freud, other scientists have offered alternative explanations
1:32
for why we dream. One of the most prominent is
1:35
the threat stimulation I'm sorry threat simulation theory, proposed by
1:41
Finnish neuroscientist and psychologist Anti Ravonsuo in two thousand. According
1:50
to this view, dreaming is an ancient biological defense mechanism.
1:54
By simulating dangerous situations, our brains rehearse the skills needed
2:00
to recognize and avoid threats, a kind of virtual reality
2:03
training ground for survival. A two thousand and five study
2:09
lent support to this theory by examining the dreams of
2:12
Kurdish children exposed to war and trauma compared to non
2:17
traumatized Finnish children. These children reported more frequent dreams filled
2:22
with severe threats, suggesting that their minds were practicing how
2:26
to cope with danger. But even the threat simulation theory
2:30
is debated. A two thousand and eight study comparing residents
2:34
of high crime areas in South Africa to those in
2:37
low crime parts of Wales found that South African participants,
2:41
despite facing more real world threats actually reported fewer threatening
2:46
dreams than their Welsh counterparts. This result challenges the idea
2:50
that the brain uses dreams to simulate danger when exposed
2:55
to trauma. Another theory suggests that dreams are simply a
3:00
side effect of memory consolidation, the brain's way of replaying
3:05
and reinforcing new memories while we sleep. As the brain's
3:09
hippocampus and neocortex worked together to file away fresh information,
3:14
they may also blend it with older memories, creating the
3:17
often strange mash ups we experience as dreams. Dreams may
3:23
also help us process and manage emotions, especially negative ones,
3:27
according to the emotion regulation theory of dreaming. Research focusing
3:33
on recently divorced individuals experiencing depression found that participants who
3:39
dreamed about their ex spouses were more likely to show
3:42
significant improvement in their mood one year later, particularly if
3:46
their dreams were vivid and emotionally rich. Another study found
3:51
that people who dreamed about stressful events they had experienced
3:54
before sleep woke up feeling more positively about the events
3:58
the next day, Such as that dreams can help transform
4:02
emotional distress into resilience. Recent brain imaging studies support this idea.
4:09
People who frequently experience fear related dreams show reduced activation
4:15
in fear centers of the brain during waking life, hinting
4:19
that these dreams may serve as a kind of overnight
4:22
therapy session, helping us better regulate our emotions when awake. Ultimately,
4:28
Barrett suggests that we may be asking the wrong question.
4:32
Quote we'd rarely ask the analogis question what is the
4:36
purpose of thinking? She says, just as waking thought serves
4:42
many functions, from planning to problem solving to daydreaming, dreams
4:47
likely do too. Quote. The value of dreaming lies in
4:51
its difference. It's a distinct mode of thought, one that
4:55
supplements and enriches our waking cognition. In fact, some researchers
5:03
believe dreams offer a unique mental space for solving problems
5:07
that stump us during the day. In this altered brain state,
5:11
regions responsible for imagery become more active, allowing a mind
5:16
to solve problems requiring visualization. History is full of famous examples.
5:22
Mary Shelley reportedly dreamed the central scenes of Frankenstein. German
5:28
chemist Auguste Kekule envisioned the ring structure of Benzene in
5:33
a dream, and Russian chemist Dmitri Mendeleev dreamed his final
5:37
form of the periodic table of the elements. In the end,
5:42
dreams may serve many purposes or none at all, but
5:44
they remind us that even in sleep, the brain never
5:48
truly rests. And now we go to Wired Magazine. This
5:55
article's headline Scientists discover the key to Axelottel's ability to
5:59
reach generate limbs written by Anna Legos and dated June seventeen.
6:07
The axe Lotel seems like something out of science fiction.
6:11
This perpetually youthful looking Mexican salamander possesses a superpower that
6:16
defies biology as we know it, the ability to regenerate
6:20
entire limbs, parts of its heart, and even its spinal cord.
6:26
But how does an amputated limb know whether to regenerate
6:29
an entire arm from the shoulder down or just a
6:33
hand from the wrist. This mystery of positional identity has
6:38
fascinated scientists for decades. A team at Northeastern University led
6:43
by James Monaghan has unraveled a key piece of this
6:47
biological puzzle in a study published in Nature Communications. The
6:52
researchers reveal an elegant molecular mechanism that acts like a
6:57
GPS coordinate system for regenerating cells. Surprisingly, the secret lab
7:05
is not in producing more of a chemical signal, but
7:09
in how quickly it is destroyed. Monahan's lab houses about
7:14
five hundred acxiltels, cared for by a team ranging from
7:18
undergraduate students to postdocs. Quote Raising acxi lottels involves managing
7:24
a complex aquatic system and being patient as they reach
7:28
sexual maturity within a year. It's slower than with other
7:32
model organisms, but also more exciting. In many experiments, the
7:36
team is exploring completely new terrain, Monaghan says. For more
7:41
than two decades, Monahan's lab has been studying the axe
7:44
lottl to understand how it regenerates complex organs such as
7:48
its limbs, vital cord, heart, and tail. His lab's research
7:53
focuses on uncovering why nerves are essential to this process
7:58
and what unique cellular properties allow axilotels to regenerate tissues
8:04
that other animals cannot. These findings could transform our understanding
8:09
of bodily regeneration and have important applications in regenerative medicine.
8:16
For years we've known that retonoic acid, a derivative of
8:20
vitamin A, is a grit crucial molecule that screens to
8:24
cells mild a shoulder, explains Monahan. But the puzzle was
8:29
how the cells in the regenerating limb stump controlled their
8:34
levels so precisely to know exactly where they were on
8:39
the axis from shoulder to hand. To unpack this mystery,
8:44
the team focused on a cluster of stem cells that
8:47
form at the wound site after a limb is lost.
8:51
In animals like the axilotel that are capable of regeneration
8:55
known as the blasphema, it's this base of stem cells
8:59
that then orchestrates regeneration. The prevailing theory was that differences
9:05
in retinoic acid might explain why a shoulder a proximal
9:11
amputation leads to an entire limb being regenerated, while a
9:16
wrist a distal amputation only regenerates the hand. Our big
9:22
surprise was to discover that the key was not in
9:24
how much retinoic acid was produced, but in how it
9:28
was degraded, says Monahan. The team discovered that cells in
9:32
the distal part of the limb the risk are a
9:35
wash in an enzyme called CYP twenty six V one,
9:40
whose sole function is to destroy retinoic acid. In contrast,
9:45
cells in the shoulder have hardly any of this enzyme,
9:48
allowing retinoic acid to accumulate to high levels. This difference
9:53
creates a chemical gradient along the limb, lots of retinoic
9:57
acid in the shoulder little in the wrist. It is
10:01
this gradient that informs cells of their exact location. In humans,
10:05
this pathway of cellular plasticity is absent or closed. Therefore,
10:11
the great challenge is to understand how to induce this
10:14
blastomal state in our cells, a key transient structure in regeneration.
10:20
If achieved, it would be possible for our cells to
10:23
respond again to positional and regenerative signals as they do
10:29
in the axolotl, explains Monahan. To confirm their discovery, the
10:35
researchers conducted in experiment. They amputated axolotal legs at the
10:40
wrist and administered a drug called talosol, which inhibits the
10:45
CYP twenty six P one enzyme by turning off the
10:49
brakes on retinoic acid. It accumulated to extremely high levels
10:54
in a place where it normally shouldn't as a result
10:57
of wrist cells, confused by the high concentration of retinoic acid,
11:02
interpreted position as being the shoulder. Instead of regenerating a hand,
11:07
they proceeded to regenerate a complete, duplicated limb. It was
11:11
the ultimate test, Monahan says. The team went a step
11:18
further to identify which genes were activated by these high
11:21
levels of retinoic acid. They discovered a master gene that
11:25
was specifically activated in shoulder areas, shocks. SHOX, an abbreviation
11:32
of short stature homeobox gene. SHOX is so called because
11:37
mutations to it in humans cause short stature. We identified
11:42
SHOCKS as a critical instruction manual in this process. Monahan explains,
11:47
it's the gene that tells developing cells to build the
11:50
arm and forearm bones. To confirm this, the team used
11:55
Crisper gene editing technology to knock out the SHOCKS gene
11:59
in axalottal embryos. The resulting animals had had peculiar limbs,
12:05
normal size hands and fingers, but significantly shorter and underdeveloped
12:10
arms and forearms. This demonstrated that SHOCKS is essential for
12:14
shaping proximal but not distal structures, revealing that regeneration uses
12:20
distinct genetic programs for each limb segment. This study not
12:25
only solves a long standing mystery of regenerative biology, but
12:29
also provides a molecular roadmap. By understanding how the AXOLOTL
12:34
reads and executes its genetic instructions for regeneration, scientists can
12:39
begin to think about how someday we might learn to
12:42
write our own genetic instructions. The AXALOTL has cellular properties
12:48
that we want to understand at the deepest level, says Monahan.
12:51
While regeneration of a complete human limb is still in
12:54
the realm of science fiction, each time we discover a
12:57
piece of this genetic blueprint, such as the role of
13:00
CYP twenty six B one and shocks, we move one
13:05
step closer to understanding how to orchestrate complex tissue repair
13:09
in humans. To bring this science closer to clinical applications,
13:14
one crucial step is to succeed in inducing blas STEMA
13:18
formations of stem cells at sites of amputation in humans.
13:23
This is the holy grail of regenerative biology. Understanding the
13:27
minimal components that make it up the molecular signals a
13:31
cellular environment. The physiological conditions would allow us to transform
13:36
a scar into a regenerative tissue, explains Monihan. In his
13:41
current research, there are still gaps to be filled, how
13:44
the CYP twenty six B one gradient is regulated, how
13:49
retanoic acid connects to the shocks gene, and what downstream
13:53
factors determine the formation of specific structures such as the
13:58
humorous or radius moment. Monahan explains that axelotels do not
14:03
possess a magic gene for regeneration, but share the same
14:08
fundamental genes as humans. The key difference lies in the
14:12
accessibility of those genes. While an injury in humans activates
14:17
genes that induce scarring, in salamanders, there is cell d differentiation.
14:23
The cells return to an embryonic like state where they
14:27
can respond to signals such as retinoic acid. This ability
14:31
to return to a developmental state is the basis of
14:35
their regeneration, explains the researcher. So if humans have the
14:40
same genes, why can't we regenerate? The difference is that
14:44
the salamander can reaccess that developmental program after injury. Humans cannot.
14:51
They only access this development pathway during initial growth, before birth,
14:56
we've had selective pressure to shut down and heal. Monan says,
15:00
my dream and the community's dream, is to understand how
15:03
to make the transition from scar to blasphema. Monahan says
15:08
that in theory, it would not be necessary to modify
15:11
human DNA to induce regeneration, but to intervene at the
15:15
right time and place in the body with regulatory molecules.
15:20
For example, the molecular pathways that signal a cell to
15:23
be located in the elbow on the pinky side and
15:26
not the thumb could be reactivated in a regenerative environment
15:31
using technologies such as crisper. This understanding could be applied
15:37
in stem cell therapies. Currently, laboratory grown stem cells do
15:41
not know where they are when they are transplanted. If
15:44
they can be programmed with precise positional signals, they could
15:48
integrate properly into damaged tissues and contribute to structural regeneration,
15:54
such as forming a complete humorous says Monahan. After years work,
16:00
understanding the role of retinoic acid studied since nineteen eighty one,
16:05
is a source of deep satisfaction. From my hand. The
16:08
scientist imagines a future where a patch placed on a
16:11
wound can reactivate developmental programs in human cells, emulating the
16:17
regenerative mechanism of the salamander. Although not immediate, he believes
16:24
that SELL engineering to induce regeneration is a goal already
16:29
within the reach of science. He reflects on how the
16:34
axelotel has had a second scientific life. It was a
16:38
dominant model one hundred years ago, then fell into disuse
16:41
for decades, and now has re emerged thanks to modern
16:44
tools such as gene editing and SELL analysis. The team
16:50
can study any gene and SELL during the regenerative process.
16:58
And now from Popular Science, we have another article focusing
17:02
on the axolotl and this headline is axalottl mucous peptides
17:07
attack breast cancer cells and MRSA dated June seventeenth. Among
17:14
animals that can regrow their detached limbs, Mexico's axolotls stand out.
17:20
These endangered amphibians can also regrow organs, including parts of
17:24
its brain and heart. Now biologists are looking closer at
17:28
the mucus on these masters of regrowth. The antimicrobial peptides
17:34
AMP in the axolottl's mucous membranes protect them from pathogens. Now,
17:41
a new study believes that this Internet famous animal could
17:44
hold some solutions to antibiotic resistance. Its antimicrobial peptides were
17:51
effective against multi resistant bacteria, including the dreaded methicillin resistant
17:58
Staphylococcus aureus or and helped combat cancer cells. The results
18:04
are described in a study recently published in the journal
18:08
plos one. Antimicrobial peptides are among the most promising candidates
18:14
for tackling further antibiotic resistance. They are found in almost
18:20
all living organisms and are part of the innate immune system.
18:24
Antimicrobial peptides could be an alternative to antibiotics in the future.
18:28
Study co author doctor Peter Vote, surgeon and clinic director
18:32
at Kirsten Reimer's laboratory at the Clinic for Plastic Esthetic,
18:38
Hand and Reconstructive Surgery in Hanover, Germany. They have a
18:43
broad spectrum of activity and at the same time it
18:45
is more difficult for pathogens to develop resistance. Axelotels in
18:50
the wild are threatened with extinction largely due to habitat degradation, pollution,
18:55
and non native predators. In their small geographic range in
18:59
southern Mexico City, the Lakes and canals. The Ambistoma mexicanom
19:05
bio Regeneration Center is currently home to the axelotal species
19:12
Ambistoma mexicanom, among other amphibian species that scientists can examine.
19:17
All the animals in this study come from captive breeding.
19:22
To obtain skin mucus for his new study, the axilotels
19:26
were gently massaged with sterile gloves. The mucus produced by
19:29
the amphibians was removed from the gloves with steril scrapers.
19:33
According to the team, this work was done in accordance
19:35
with the guidelines of the German Animal Welfare Act. Out
19:39
of the thousands of antimicrobial peptides extracted, the team selected
19:44
twenty two likely effective peptide candidates. This is time consuming
19:49
and expensive, but unfortunately amps are not as easy to
19:52
produce in microorganisms as some antibiotics. Explained vote the chemical
19:58
structure and mechanism are what make them so difficult to produce.
20:03
They all contain amino acids with a positive charge and
20:06
have water repellent components so that they can bind to
20:10
the cell wall of bacteria. Once attached to the bacterial
20:14
cell wall, they either create small holes in it to
20:17
penetrate the cell or bind to molecules. Both processes damage
20:23
the cell and lead to death. Antimicrobial peptides can also
20:27
act against viruses and fungi. According to study co author
20:33
Sarah Straub, that special chemical structure could be what makes
20:38
antimicrobial peptides effective against resistant bacterial strains and might reduce
20:44
the risk of further resistance. Harnessing the power of that
20:48
chemical structure could yield a decisive advantage, since even reserve
20:53
antibiotics are at risk of losing efficacy against bacteria. Reserve
20:58
antibiotics are used for infections caused by bacteria when conventional
21:03
antibiotics are no longer effected. This is the case in MERSA,
21:07
which causes roughly twenty thousand infections per year in the US.
21:12
Four of the oxalotal antimicrobial peptides showed efficacy against MERSA.
21:18
In some cases, they were even more effective than the
21:20
reserve antibiotic. The results against MERSA are particularly significant because
21:25
the spread of this multi resistant bacterial strain will continue
21:29
to increase with the over use of antibiotics in both
21:33
health care and agriculture, said Vote. The team also detected
21:40
an anti carcinogenic effect in three of the four antimicrobio peptides.
21:45
This group also was effective against MERSA. In a cell culture,
21:49
these peptides triggered a program cell death in breast cancer cells.
21:53
Program cell death is a controlled biological program in which
21:57
the effected cell dies in a lab. We observe that
22:00
the peptide specifically kidle cancer cells without attacking healthy breast
22:04
tissue cells, Straub said. Overall, our results suggest that these
22:09
identified amps could be promising candidates for combating antimicrobic resistance
22:16
and for anti cancer strategies. While more studies are needed
22:20
to verify these results, they are a basis for additional
22:24
research into what future therapeutics are lurking in axelattle mucus.
22:31
Now we have an article from National Geographic what we
22:33
can learn from the genius of beavers. The East Troublesome
22:38
Fire erupted on October twenty first, twenty twenty. Whipped by
22:43
strong winds and fueled by drought parched forests, the fire
22:47
roared through northern Colorado's spruce and fir woods. It leaked
22:51
roads and rivers, and the Continental Divide, scaling mountain passes
22:55
above tree line. It incinerated historic buildings in Rocky Mountain
22:59
National Park and homes in Grand County, killing two people. Ultimately,
23:05
it torched nearly two hundred thousand acres, making it the
23:08
second largest fire in Colorado's history. In the end, just
23:12
about the only thing the East Troublesome didn't consume was
23:16
beaver ponds. This was not entirely surprising. Beavers, of course,
23:21
build dams that store water, and water, as you may know,
23:24
doesn't burn. But the benefit the semi aquatic rodents provide
23:29
goes further than that. In a study published weeks before
23:33
the East Troublesome blew up, Emily Fairfax and eco hydrologists
23:38
now at the University of Minnesota, found that beaver ponds
23:42
and canals irrigate the landscape so thoroughly that they turned crisp,
23:46
flammable pint plants into lush, fireproof ones, forming green refuges
23:52
in which wild life and livestock can retreat. In a
23:55
nod to another firefighting icon, Fairfax and her co author
24:00
titled their paper Smoky the Beaver. Fairfax studied five fires
24:05
between two thousand and twenty eighteen to reach her conclusions,
24:09
but the East Troublesome was far bigger than most of those.
24:12
Blazes and a harbinger of the kind of conflagration we're
24:15
seeing more and more. Although fire has long been a
24:19
natural force of regeneration on North American landscapes, the so
24:23
called mega fires that plague the ever drier West are
24:27
a different matter, stoked by climate change into explosive infernos
24:32
that can burn so big and hot that ecosystems don't
24:35
always readily recover. Fairfax doubted whether beavers could steal fireproof
24:40
large tracts of landscape under those conditions, but when she
24:44
visited the charred forests left behind by the East Troublesome
24:48
and one other megafire, she discovered that the oases beavers
24:53
created with their ponds had endured these. There are entire
24:58
rivers that are basically unaffected by the fire because it's
25:01
just beaver dams the whole way, she said, Everything is
25:05
full of life. The reeds are growing, the pine needles
25:07
are still on the trees. The ponds aren't merely helpful
25:11
before a fire. They can also protect ecosystems from the
25:14
effects that come right after a blaze, capturing the ash
25:18
and debris that run off illsalt hill slopes and shielding
25:22
downstream fish and drinking water. In a twenty twenty four
25:26
paper describing their findings, Fairfax and her collaborators concluded that
25:31
beaver's quote can be part of a comprehensive fire mitigation
25:36
strategy end quote. Once hunted to near extinction for their
25:40
pelts and later villainized as a nuisance, beavers have rebounded.
25:45
There are now ten to fifteen million swimming and waddling
25:49
across most of North America, and they're ready for their
25:53
third act. Cast in an improbable role. Ecological saviors to
25:58
a climate change ravaged war, and fire mitigation is just
26:02
the start. By building dams that slow stream flow, they
26:06
create reservoirs that help combat drought. By sculpting wetlands, they
26:11
furnish habitat for other animals. Nowhere is their return more
26:18
unnecessary than in the climate stressed American West, where beaver
26:22
restoration is unfolding to some extent in every state. But beavers,
26:28
tireless meddlers with a penchant for running a foul of
26:30
human infrastructure, aren't yet universally welcome. The sand Pedro River
26:37
snakes across Arizona's border with Mexico through the sun blasted
26:41
Sonoran Desert. Though the arid land seems better suited for
26:45
rattlesnakes than semi aquatic rodents. Frontiersmen once knew the San
26:50
Pedro as the Beaver River, before nineteenth century trappers stripped
26:55
it clean. Anywhere there were perennial waters, there were probably beavers,
26:59
says lisa's Speck, the director of a nonprofit called the
27:04
Watershed Management Group. In nineteen ninety nine, in hopes of
27:08
enhancing the area's wildlife habitat, the Bureau of Land Management
27:12
restocked the sand Priedro with sixteen beavers, whose offspring dispersed
27:16
throughout the river, including into Mexico. Since twenty twenty, Shepeck,
27:21
along with Mexican biologists and legions of volunteers, has been
27:25
scouring the river to estimate the population. Along the trunk
27:29
of one down cottonwood, beavers had chiseled away the bark
27:32
to expose hartwood and whittled limbs to blunt points. Pale
27:37
chips covered the banks. They were probably here within the
27:41
last few weeks, Shepeck half whispered, it's easy to emphas
27:45
empathize with beavers. Like many of us, they live in
27:48
nuclear families on land. Beavers are clumsy, morsels for cougars
27:53
and wolves and bears, but they are very good swimmers,
27:56
endowed with transparent eyelids and webbed hind feet. Well that's
28:01
all for today's Diary of Science and Nature. The reader
28:05
is Kelly Taylor. Now stay tuned for the Health Core
28:08
on RADIOI