Author Archives: Jasper Yoo

Key protein in spinal cord regeneration found

Researchers at Duke University have identified a key protein used in spinal cord regeneration in zebrafish. The findings were presented in the November 4 edition of the Science journal.

An adult female zebrafish. Authorized for redistribution by the copyright holder. Retrieved from https://en.wikipedia.org/wiki/Zebrafish.

An adult female zebrafish. Authorized for redistribution by the copyright holder. Retrieved from https://en.wikipedia.org/wiki/Zebrafish.

While zebrafish can completely regenerate their spinal cords even after it is severed, humans cannot. This makes spinal cord injuries (SCI) one of the most debilitating injuries for humans, as ability to walk and sense can be impaired. As SCI can be permanent, many patients require lifelong assistance with daily activities, resulting in loss of autonomy.

Diagram of the spinal cord. Image in the public domain; retrieved from https://en.wikipedia.org/wiki/Spinal_cord_injury

Diagram of the spinal cord. Image in the public domain.

When a zebrafish’s spinal cord is undergoing regeneration, a bridge forms. The first cells (a cell is the basic functional unit of all living things) project lengths many times their own size and connect a wide length of the injury. This is followed by nerve cells, and after eight weeks, new nerve tissue has filled the gap formed by the injury, reversing the zebrafish’s paralysis.

Nerve cells in the brain. Shared under the Creative Commons license. Retrieved from https://en.wikipedia.org/wiki/Neuron.

Nerve cells in the brain. Shared under the Creative Commons license. Image by UC Regents Davis campus.

The researchers looked for genes (the basic functional units, made up of DNA, that instruct the body how to make proteins) whose activities changed throughout this process, and they focused on a protein called connective tissue growth factor (CTGF), as they found more of it in the supporting cells (glia) that formed the bridge within two weeks of the injury than before.

Glial cells in a rat brain. Public domain. Retrieved from https://en.wikipedia.org/wiki/Neuroglia.

Glial cells in a rat brain. Public domain.

This finding is important because it provides a direction for research in achieving full recovery of function in patients with SCI. Although the researchers say that CTGF alone will probably not be enough for spinal cord regeneration due to scar tissue (new tissue that forms after injuries) in mammals, now that CTGF has been identified as a key protein for regeneration, it could be used with other proteins and therapies. The researchers expect that studies on CTGF will move towards mammals like mice.

In addition, knowing this new information about CTGF can lead research towards similar proteins. Indeed, the researchers themselves have indicated plans to study the other secreted proteins they observed when looking for genes with altered activities throughout the zebrafish’s healing process.

Permanent SCI have debilitating physical and psychological effects on their patients, their families, and the support system around them. An estimated 24-45% of people with SCI suffer from depression, and the suicide rate can be as great as six times of the general population. In fact, in young people with SCI, it is suicide that is the leading cause of death and not physical complications of the injury itself. The psychological impact is tragic, which is one of the reasons why I believe that improving patient outcomes for SCI is one of the most pressing needs for modern medicine, and also why I hope research funding continues to go towards spinal cord research.

-Jasper Yoo

The Atmosphere of Earth Is Leaking Oxygen

Although oxygen composes 21% of the Earth’s atmosphere, oxygen levels are not stable. Through analysis of air bubbles caught inside ice cores (core samples of ice taken from ice sheets or glaciers) in Greenland and Antarctica, Princeton University researchers determined that oxygen levels dropped 0.7% over the past 800,000 years.

A sliver of Antarctic showing air bubbles trapped within it. Image from http://www.scienceimage.csiro.au/pages/about/.

A sliver of Antarctic showing air bubbles trapped within it. Image from http://www.scienceimage.csiro.au/pages/about/, published under the Creative Commons license.

The full research article was published in the September 23 issue of Science journal. While the researchers are not sure why the oxygen drop occurred, researcher Daniel Stolper believes that it is due to the increase in global erosion rates. Erosion is the process in which earth is worn away, often due to processes like rain or wind. Grinding of rocks by glaciers (large bodies of ice that move under their own weight) results in erosion, and the growth of glaciers over the past tens of million years has increased Earth’s erosion levels.

Aletsch Glacier in Switzerland. Photograph by Mike Peel (www.mikepeel.net)

Aletsch Glacier in Switzerland. Photograph by Mike Peel (www.mikepeel.net), published under the Creative Commons license.

How does erosion relate to oxygen levels? Erosion would expose increased pyrite and organic carbon to the atmosphere.

Pyrite from Tuscany, Italy. Image by Didier Descouens, published under the Creative Commons license.

Pyrite from Tuscany, Italy. Image by Didier Descouens, published under the Creative Commons license.

Pyrite, colloquially known as “fool’s gold” for physically resembling gold, reacts with oxygen and removes it from the atmosphere. Organic carbon has been found to do the same thing.

In terms of immediate impact on Earth, the drop is trivial because of how slow it is. Organisms have had time to adapt to the change in atmospheric oxygen. However, atmospheric oxygen levels are linked to climate change and how organisms evolve, so understanding its trends is important. For example, changing oxygen levels can alter how living things adapt, and from an evolutionary standpoint, declining oxygen levels would prefer individuals and species who are more efficient with their use of oxygen.

Understanding oxygen levels can also be the key to understanding long-term weather trends, and further research could determine if there are any links between this observation about oxygen levels and the global warming crisis that we are facing today.

In addition, understanding the processes behind the declining oxygen levels and observing how living things have adapted to it over time could help humans understand what is needed for a habitable environment. With continued efforts to build a feasible human settlement in Mars, having a better grasp of what is needed for life on Earth would be important if humans are ever to colonize Mars. As lack of atmospheric oxygen is one of the major obstacles to life on Mars, understanding how living things on Earth react to lower levels of oxygen could allow for potential ideas on how to survive in Mars’ low-oxygen conditions.

Photograph of Mars by the Hubble Space Telescope. Image by NASA.

Photograph of Mars by the Hubble Space Telescope. Public domain. Image by NASA.

Therefore, although these findings do not have an immediate impact on Earth, they carry big implications both for humanity’s future and understanding our planet’s past.

-Jasper Yoo

The Atmosphere of Earth Is Leaking Oxygen

Although oxygen composes 21% of the Earth’s atmosphere, oxygen levels are not stable. Through analysis of air bubbles caught inside ice cores (core samples of ice taken from ice sheets or glaciers) in Greenland and Antarctica, Princeton University researchers determined that oxygen levels dropped 0.7% over the past 800,000 years.

A sliver of Antarctic showing air bubbles trapped within it. Image from http://www.scienceimage.csiro.au/pages/about/.

A sliver of Antarctic showing air bubbles trapped within it. Image from http://www.scienceimage.csiro.au/pages/about/, published under the Creative Commons license.

The full research article was published in the September 23 issue of Science journal. While the researchers are not sure why the oxygen drop occurred, researcher Daniel Stolper believes that it is due to the increase in global erosion rates. Erosion is the process in which earth is worn away, often due to processes like rain or wind. Grinding of rocks by glaciers (large bodies of ice that move under their own weight) results in erosion, and the growth of glaciers over the past tens of million years has increased Earth’s erosion levels.

Aletsch Glacier in Switzerland. Photograph by Mike Peel (www.mikepeel.net)

Aletsch Glacier in Switzerland. Photograph by Mike Peel (www.mikepeel.net), published under the Creative Commons license.

How does erosion relate to oxygen levels? Erosion would expose increased pyrite and organic carbon to the atmosphere.

Pyrite from Tuscany, Italy. Image by Didier Descouens, published under the Creative Commons license.

Pyrite from Tuscany, Italy. Image by Didier Descouens, published under the Creative Commons license.

Pyrite, colloquially known as “fool’s gold” for physically resembling gold, reacts with oxygen and removes it from the atmosphere. Organic carbon has been found to do the same thing.

In terms of immediate impact on Earth, the drop is trivial because of how slow it is. Organisms have had time to adapt to the change in atmospheric oxygen. However, atmospheric oxygen levels are linked to climate change and how organisms evolve, so understanding its trends is important. For example, changing oxygen levels can alter how living things adapt, and from an evolutionary standpoint, declining oxygen levels would prefer individuals and species who are more efficient with their use of oxygen.

Understanding oxygen levels can also be the key to understanding long-term weather trends, and further research could determine if there are any links between this observation about oxygen levels and the global warming crisis that we are facing today.

In addition, understanding the processes behind the declining oxygen levels and observing how living things have adapted to it over time could help humans understand what is needed for a habitable environment. With continued efforts to build a feasible human settlement in Mars, having a better grasp of what is needed for life on Earth would be important if humans are ever to colonize Mars. As lack of atmospheric oxygen is one of the major obstacles to life on Mars, understanding how living things on Earth react to lower levels of oxygen could allow for potential ideas on how to survive in Mars’ low-oxygen conditions.

Photograph of Mars by the Hubble Space Telescope. Image by NASA.

Photograph of Mars by the Hubble Space Telescope. Public domain. Image by NASA.

Therefore, although these findings do not have an immediate impact on Earth, they carry big implications both for humanity’s future and understanding our planet’s past.

-Jasper Yoo