Thanks to Nature’s Fynd for sponsoring this episode.
We teamed up with Nature’s Fynd
to explain the science behind their fungi-based foods.
Check out the link in the description to learn more.
[♪ INTRO]
Anyone with seasonal allergies can tell you that springtime… is a mixed blessing.
And for the some 150 million people worldwide who suffer from allergic asthma,
it can be particularly terrible.
Coughing, wheezing, shortness of breath, and a tight chest are common.
But hope might be on the horizon, with scientists announcing this week that
they’ve developed a vaccination to protect against allergic asthma.
At least... in mice.
Allergic asthma is a specific form of asthma where the body becomes sensitivE
to some kind of allergen -- like pollen or dust.
So then when someone is exposed to those particles, their bodies mount an immune response,
releasing proteins called cytokines from immune cells.
One of those cytokines -- called IL-4 -- triggers the body to make antibodies,
including one called IgE.
IL-4, together with another cytokine called IL-13, are one cause
of the symptoms we know of as allergic asthma.
Some treatments do exist, targeting these immune molecules.
But they can be pricey, and people may have to take them for years, or even for the rest of their life.
In a study published this week in the journal Nature Communications,
researchers developed vaccines against the main allergic asthma culprits, IL-4 and IL-13.
Now, if you’re thinking that it seems a little weird to vaccinate ourselves against
our own immune systems, well it’s a little weird!
But here’s how that would work.
The whole reason allergic asthma sufferers have symptoms is because
their bodies are having an immune response to an allergen, mediated in part by those
cytokines.
These vaccines are designed to raise neutralizing antibodies:
antibodies that will stick to those cytokines and stop them from causing that response.
Now, these are conjugate vaccines, which are kind of super-powered vaccines
designed to create a longer-lasting immune response.
And they’re called conjugate because they combine a molecule that usually
triggers a weak immune response with one that triggers a strong one.
In the case of the asthma vaccine, researchers combined each of the IL-4 and IL-13 cytokines
with a non-toxic form of the diphtheria protein,
which is a commonly-used carrier in conjugate vaccines because it sets off a really strong
immune response.
The diphtheria carrier is what tells the body that these cytokines actually aren’t helpful here
and it should make some neutralizing antibodies against them.
In the study, researchers administered these conjugate vaccines to mice.
The mice received either two conjugate vaccines, one for each cytokine;
a vaccine for only one of the cytokines; or a control vaccine that only had the carrier.
They all got four doses of a vaccine or control over about two months.
At around day forty, the researchers induced allergic asthma in the mice by spraying dust
mites up their noses.
And they saw that mice who had received both vaccines had less severe asthma symptoms
than those who only got one, or the ones who got the control.
The double-vaccinated mice also had higher levels of neutralizing antibodies against
those cytokines
and lower levels of the asthma IgE antibody.
That effect lasted up to fifteen weeks in some mice.
The researchers also tested their vaccine on mice
that had been engineered to produce the human versions of these cytokines -- and they got
very similar results.
That means making the jump from a mouse model to a human model might be easier --
though it’s never a sure thing.
The researchers now want to confirm their findings with human trials,
and hopefully develop a more cost-effective source of relief for people with allergic asthma.
Now, from mice to very large predators.
The California condor has been making a comeback
after its numbers dropped to just 22 individuals in the early 1980s.
This vulture-like bird of prey is the largest bird in North America.
And thanks to a captive breeding program, its numbers are now up
to around 300 in the wild and 200 in captivity.
And it’s not just their numbers that have rebounded.
Their gene pool is also looking pretty healthy, according to a paper published in the journal
Current Biology.
When a species’ numbers drop really low, it creates what’s called a genetic bottleneck
meaning there’s very little genetic diversity in the population.
Fewer individuals means fewer alleles -- or different versions -- of the same gene,
simply because it’s not likely for that small sample to preserve every allele
that was present in the larger population.
That can decrease a population’s ability to adapt to changing environments,
since there are fewer options -- genetically speaking -- for how to cope.
In this study, researchers first sequenced the condor genome.
Then, they compared the genome from two California condors to the genetic makeup of two of their relatives --
the Andean condor and turkey vulture -- to see how many unique alleles the California
species had.
In other words, they were looking for heterozygosity.
Since genes come in pairs, heterozygosity is every place in the genome
an individual has two different alleles instead of a pair of the same one.
The more heterozygosity, the more diverse the genome and, theoretically, the healthier
the population.
Researchers saw lots of similarity between the two California condor individuals,
telling them that there was a bottleneck and some inbreeding in the past when the species
was near extinction.
But outside of particular regions of the genome, and compared to their condor relatives,
California condors were surprisingly genetically diverse.
Overall, they had similar levels of heterozygosity to the turkey vulture, the species that had
the most.
And they’re more diverse than another iconic American bird species, the bald eagle,
who was also brought back from the brink through heavy conservation efforts.
In fact, for the California condor, it looked like the bottleneck
had actually gotten rid of a bunch of harmful genes in the process.
The study is a great start to understanding the genetics of this species,
but researchers want to extend their work to include more wild individuals.
That could help them understand the genetic basis of disorders
that affect the condors, like abnormal skeleton growth.
That information could be used to improve the ongoing breeding programs,
to help bring back healthier condors.
Thanks for watching this episode of SciShow,
which was brought to you by Nature’s Fynd, the fungi-based food company for optimists.
The climate is getting warmer and threatening our food system.
But through their NASA-backed research and breakthrough fermentation technology,
Nature’s Fynd creates sustainable, vegan foods from tiny fungi!
And the food is delicious!
I had some of their cream cheese.
And then I went home to my wife to tell her about it, because it was that good.
It was …
… maybe better than regular cream cheese???
I’m excited about this cream cheese.
Any excuse to eat more bagels.
If you want to learn more about Nature’s Fynd and the science behind their fungi-based foods,
Check the link in the description.
[♪ OUTRO]