Why plants don’t
Plants rely on sunlight for photosynthesis,
but they also need protection from harmful
UVB radiation, just as humans do. Recently,
researchers discovered a group of molecules in plants that shield them from UVB
radiation. Now, in an article in the Journal
of the American Chemical Society, one team
reports on the mechanics of how these
natural plant sunscreens work.
Timothy Zwier and colleagues at Purdue University note
that the UVB radiation to which plants are exposed daily
can cause mutations to a plant’s DNA and hinder its growth.
Biochemical tests have shown that plants produce sinapate
esters and send them to the outer layer of their leaves to
protect themselves. These molecules appear to block UVB
radiation from penetrating deeper into leaves where it
might otherwise cause DNA mutations. Although research-
ers have been amassing evidence that points to sinapate
esters as the protective molecules, no one had investigated
in detail what happens to them
under UV exposure in an iso-
lated environment. Zwier’s
team wanted to understand
this process, which
they explored by
testing a series
of sinapic acid
the sinapate esters into
the gas phase and exposed
them to UVB radiation
from a laser. They
found that sinapoyl
plants use as a
ble of soaking
up radiation at
across the UVB
they are remark-
ably efficient at
could otherwise damage the plant. These findings further
strengthen the idea that sinapate esters function as plant-made sunblock.
Read more about the research: “Plant Sunscreens in
the UV-B: Ultraviolet Spectroscopy of Jet-Cooled Sinapoyl
Malate, Sinapic Acid, and Sinapate Ester Derivatives,”
Journal of the American Chemical Society, 2014, 136 (42), pp
Tonsil stem cells could
someday help repair liver
damage without surgery
The liver performs critical functions, such as ridding the body
of toxins. Its failure can be deadly, and there are few options
for repairing it. But in the journal ACS Applied Materials & Interfaces, researchers now report on a way to potentially inject
stem cells from tonsils, a body part we don’t need, to repair
damaged livers — all without surgery.
Byeongmoon Jeong and colleagues point out that currently, the only established
method for treating liver failure or severe cases of liver disease is complete or partial
transplantation. But the need is much greater than the number of available organs.
Plus, surgery has inherent risks and a hefty price tag. A promising alternative in development is transplanting liver cells. One such approach involves using adult stem cells
to make liver cells. Stem cells from bone marrow could be used, but they have limitations. Recently, scientists identified another source of adult stem cells that could be
used for this purpose — tonsils. Every year, thousands of surgeries are performed to
remove tonsils, and the tissue is discarded. Now it could have a new purpose, but
researchers needed a way to grow them on a 3D scaffold that mimics real liver tissue.
Jeong’s team set out to do just that.
The researchers encapsulated tonsil-derived stem cells in a polypeptide thermogel
that turns into a gel at body temperature. They added growth factors to encourage
the stem cells to become liver cells. Then, they heated the combination up to a normal
body temperature. The result was a 3D, biodegradable gel that contained functioning liver cells. The researchers conclude that the
same process has
promise — with
ideal conditions — as
technique to treat liver
disease without surgery.
Read more about the research: “
Polypeptide Thermogels as a Three Dimensional
Culture Scaffold for Hepatogenic Differentiation of Human Tonsil-Derived Mesenchymal
Stem Cells,” ACS Applied Materials & Interfaces,
The number of “lead” pencils one could fill from
the amount of carbon in the human body.
80 The length of wire in kilometers
that can be formed from
stretching an ounce of gold.
The atomic number
of chromium, the
that is responsible for
the red color of rubies
and the green of
strength of the world’s strongest superacid,
fluoroantimonic acid, to 100% sulfuric acid.