A breathtaking trick potentially left over
from our ancestors might be found in us — the ability to sense oxygen through
our skin.
Amphibians, animals such as frogs that can
live both on land and in water, have long been known to be capable of breathing
through their skin. In fact, the first known lungless frog that breathes only
through its skin was discovered recently in the rivers of Borneo.
Now the same oxygen sensors found in frog
skins and in the lungs of mammals (哺乳动物) have unexpectedly been discovered in the skin of mice.
“No one had ever looked,” explained Randall
Johnson, a biologist researcher.
Mice and frogs are quite distant relatives,
so the fact they have these molecules (分子) in common in their skin suggests they might well be found in the
skin of other mammals, such as humans.
“We have no reason to think that they are
not in the skin of people too,” Johnson said. These molecules not
only detect oxygen, but help increase levels of vital red blood cells, which
carry oxygen around the body. Normal mice breathing in air that is 10 percent
oxygen—a dangerously low level similar to conditions at the top of Mount
Everest, and about half that of air at sea level. However, mice that had the
oxygen sensor HIF-1a genetically removed from their skin failed to produce this
hormone (荷尔蒙) even
after hours of such low oxygen.
These findings, if they hold true in
humans, suggest one could raise the level of oxygen circulating inside the
body. This could help treat lung diseases and disorders such as anemia (贫血症) without injecting drugs,
which make up a multibillion-dollar market, Johnson said.
Athletes also often try to get more oxygen
delivered to their muscles in order to improve their performance. They often do
this by training at high altitudes or in low-oxygen tents. The new study
suggests they might want to expose their skin as well as breathing in
low-oxygen air to improve their performance. “It’s hard to say what exactly
might be done, however—there’s a lot we don’t know yet,” Johnson explained.
The scientists detailed their findings in
the April 18 issue of the journal Cell.
49. Which of the following statements is
TRUE according to the passage?
A. Johnson believes that Oxygen sensors
also exist in human skin.
B. People have to surf the Internet to read
detailed findings.
C. It has been proved that these findings
help treat lung diseases.
D. It has long been expected oxygen sensors
exist in mice’s skin.
50. One of the functions of the molecules
mentioned above is _______.
A. carrying oxygen around the
body
B. improving athletes’ performance
C. detecting
oxygen
D. increasing level of oxygen
51. What is Johnson’s attitude to the
application of the findings to the athletes’ training?
A.
Negative
B.
Doubting
C. Positive
D. Hesitating
52. The best title of the passage may be
_______.
A. Great Findings Benefits Athletes A Lot
B. Frogs And Mice Are Distant Relatives
C. First Known Animal Breathes Through Skin
D. Humans Might Sense Oxygen Through Skin