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The myth mentions "The Spindle of Necessity", in that the cosmos is represented by the Spindle attended by sirens and the three daughters of the Goddess Necessity known collectively as The Fates, whose duty is to keep the rims of the spindle revolving. The Fates, Sirens, and Spindle are used in The Republic, partly to help explain how known celestial bodies revolved around the Earth according to Plato's cosmology.
The "Spindle of Necessity", according to Plato, is "shaped ... like the ones we know"—the standard Greek spindle, consisting of a hook, shaft, and whorl.
The hook was fixed near the top of the shaft on its long side. On the
other end resided the whorl. The hook was used to spin the shaft, which
in turn spun the whorl on the other end.
Placed on the whorl of his celestial spindle were 8 "orbits", whereof
each created a perfect circle. Each "orbit" is given different
descriptions by Plato.
A lack of melanin production can be associated with albinism, visual
impairment and a greater susceptibility to skin and eye cancer. Melanin
protects DNA from ultraviolet radiation. For years, however, scientists
have had little insight into how pigmentation is governed. In late 2014,
Oancea's team discovered that melanosomes employed an ion channel,
"OCA2," whose activity increases melanin production by reducing their
acidity. OCA2 is named for the disease caused by mutations in the
protein, oculocutaneous albinism type II.
The new study, therefore, finds that TPC2 and OCA2 counterbalance.
"Having more than one ion channel regulating the pH allows for
complex regulatory mechanisms that can be fine tuned to regulate the pH
under diverse conditions," Oancea said.
In coordination with the U.S. Food and Drug Administration (FDA), the
Red Cross is seeking people who are fully recovered from the new
coronavirus to sign up to donate plasma to help current COVID-19 patients.
People who have fully recovered from COVID-19 have antibodies in
their plasma that can attack the virus. This convalescent plasma is
being evaluated as treatment for patients with serious or immediately
life-threatening COVID-19 infections, or those judged by a healthcare
provider to be at high risk of progression to severe or life-threatening
https://www.fda.gov/emergency-preparedness-and-response/coronavirus-disease-2019-covid-19/donate-covid-19-plasma#:~:text=Convalescent plasma is the liquid,from COVID-19.
Convalescent plasma is the liquid part of blood that is collected
from patients who have recovered from the novel coronavirus disease,
COVID-19, caused by the virus SARS-CoV-2. COVID-19 patients develop
antibodies in the blood against the virus. Antibodies are proteins that
might help fight the infection. Convalescent plasma is being
investigated for the treatment of COVID-19 because there is no approved
treatment for this disease and there is some information that suggests
it might help some patients recover from COVID-19.
This is weird because that's really not how adaptations usually
happen in multicellular animals. When an organism changes in some
fundamental way, it typically starts with a genetic mutation - a change
to the DNA.
Those genetic changes are then translated into action
by DNA's molecular sidekick, RNA. You can think of DNA instructions as a
recipe, while RNA is the chef that orchestrates the cooking in the kitchen of each cell, producing necessary proteins that keep the whole organism going.
RNA doesn't just blindly execute instructions - occasionally it
improvises with some of the ingredients, changing which proteins are
produced in the cell in a rare process called RNA editing.
such an edit happens, it can change how the proteins work, allowing the
organism to fine-tune its genetic information without actually
undergoing any genetic mutations. But most organisms don't really bother
with this method, as it's messy and causes problems more often that
"The consensus among folks who study such things is
Mother Nature gave RNA editing a try, found it wanting, and largely
abandoned it," Anna Vlasits reported for Wired.
But it looks like cephalopods didn't get the memo.
researchers discovered that the common squid has edited more than 60
percent of RNA in its nervous system. Those edits essentially changed
its brain physiology, presumably to adapt to various temperature
conditions in the ocean.
The team returned in 2017 with an even
more startling finding - at least two species of octopus and one
cuttlefish do the same thing on a regular basis. To draw evolutionary comparisons, they also looked at a nautilus and a gastropod slug, and found their RNA-editing prowess to be lacking.
"This shows that high levels of RNA editing is not generally a molluscan thing; it's an invention of the coleoid cephalopods," said co-lead researcher, Joshua Rosenthal of the US Marine Biological Laboratory.
The researchers analysed hundreds of thousands of RNA recording sites in these animals, who belong to the coleoid subclass of cephalopods. They found that clever RNA editing was especially common in the coleoid nervous system.
wonder if it has to do with their extremely developed brains,"
geneticist Kazuko Nishikura from the US Wistar Institute, who wasn't
involved in the study, told Ed Yong at The Atlantic.
It's true that coleoid cephalopods are exceptionally intelligent. There are countless riveting octopus escape artist stories out there, not to mention evidence of tool use, and that one eight-armed guy at a New Zealand aquarium who learned to photograph people. (Yes, really.)
it's certainly a compelling hypothesis that octopus smarts might come
from their unconventionally high reliance on RNA edits to keep the brain
"There is something fundamentally different going on in these cephalopods," said Rosenthal.
it's not just that these animals are adept at fixing up their RNA as
needed - the team found that this ability came with a distinct
evolutionary tradeoff, which sets them apart from the rest of the animal
In terms of run-of-the-mill genomic evolution (the one
that uses genetic mutations, as mentioned above), coleoids have been
evolving really, really slowly. The researchers claimed that this has
been a necessary sacrifice - if you find a mechanism that helps you
survive, just keep using it.