The Mouse I Worked With This Summer (http://jaxmice.jax.org/jaxnotes/archive/489i.html)

I spent the last summer at the Jackson Laboratory in Bar Harbor, Maine as a summer intern. The program is amazing, and I had the chance to work in a lab that studies medulloblastoma, a type of brain cancer. I learned a lot of amazing biology, but as a good portion of it is not yet published I don’t really feel that I should write about it. So instead, today I’m going to write about an interesting topic of biology that I had never really thought about until I worked at The Jackson Laboratory: mouse models. Specifically, I can think of three amazing things about the mouse models at the Jackson Laboratory.

1.      They are virtually genetically identical, but only within strains. This makes them ideal for research. In science, one wants to find results that are consistent and can be replicated so that definitive conclusions can be drawn. However, wild mice are just like people; they are all genetically different. Consequently, if scientists conducted research on wild mice, their results would often vary and conclusions would be difficult to form, as each mouse would respond slightly differently because of its different genetic makeup. The mice studied at the Jackson Lab avoid the problem of genetic variation, as they have all been engineered to be genetically identical.

How do you create a genetically identical mouse? Well it turns out that mice don’t mind mating with their brothers, sisters, and parents. So you use this fact to your advantage. First, breed two unrelated mice together. When they have their litter, then have the brothers, sisters, and parents all mate. When the next litters are formed, repeat the process. Over time, around ten generations or so, the mice will become so inbred that they are virtually genetically identical.

Now, having genetically identical mice is ideal for replication, but not ideal for modeling what actually happens in people, as people are genetically diverse. So, the ideal system is one that’s called, “genetically identical inbred strains”, and this is exactly how mouse research is done. There are multiple “strains” or types of genetically identical mouse. The mice are genetically identical, but only within each type. This enables researchers to first test if an effect happens in one type of mouse, as each mouse of this type is genetically identical, but then see if they can replicate their findings in mice that are not genetically identical. This is called replicating your findings in a “different genetic background”, and it is the most compelling evidence for any biological effect or response.

2.      They can be genetically engineered to have amazing, science fiction like mutations. Overtime, scientists have developed an incredible amount of control over the mouse genome. They can inject genes directly into the fertilized egg of a mouse, creating what’s known as a “transgenic mouse”. Or, they can induce random mutations in the mouse genome and observe the effects. Together, these processes have enabled the production of mouse models for cancer, genetic diseases, and even some forms of mental illness. For instance, the mouse I worked with this summer has been genetically engineered to develop medulloblastoma, which is a tumor in the area of the brain known as the cerebellum, by 4 months of age. Scientists have also developed mice with some interesting mutations, such as glowing green (see the mice at the bottom of the article) and being very obese:

Finally, scientists have even learned to turn on and off genes only in specific tissues. For example, the brain of the mouse model I worked with this summer glowed green.

3.      Scientists can turn off their genes. How do you find out what a particular gene does? One way to do it is to turn off a particular gene, and then see what happens to the mouse when you do. A mouse that doesn’t express a particular gene is called a “knock out mouse”, and scientists have become amazingly skilled at turning off any mouse gene. Thousands of mouse genes have already been turned off to study their function, and scientists have the goal of knocking out every gene in the mouse genome within the next few years.

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http://curiousbastard.files.wordpress.com/

It’s strange to imagine, but physicists cannot accurately describe nearly three quarters of the matter and energy in the universe. Because as it turns out, nearly 73% of the universe is composed of a mysterious substance called dark energy. In physical terms, no one knows exactly what dark energy is. Instead, dark energy is a theoretical construct that permeates all of the space in the universe and can provide an explanation as to why the expansion rate of the universe is increasing. Simply put, Dark Energy is a force that is intrinsically found in space and is causing the expansion rate of the universe to increase.

There are different opinions as to how and when Dark Energy was discovered. Although physical observations have only recently confirmed the existence of dark energy, some say that Einstein discovered Dark Energy way back when he was formulating his General Theory of Relativity. While making the General Theory of Relativity, Einstein originally added the “cosmological constant” into his equations in order create a static universe. In this original formulation of General Relativity, the cosmological constant acted as a mysterious force that caused the universe to expand; this was necessary in order for General Relativity to predict a static universe, which Einstein wanted. However, Einstein then removed this cosmological constant when observations by Hubble indicated that the Universe was expanding. But since the cosmological constant causes the Universe to expand and would permeate all of space, it is essentially dark energy.

However, others say that dark energy was really discovered in 1998, as this was the first time a physical phenomenon that required the existence of dark energy to be explained was observed. Scientists from Berkeley and scientists from Australian National University observed two supernovas that were farther apart than models would predict in a universe that lacked dark energy. Consequently, others say that these scientists discovered dark energy.

Ebola (historyfilms.net)

Evolution has created some nasty microbes…

Anthrax: Anthrax, caused by the bacterium Bacillus anthracis, is one of the most lethal microorganisms in existence, killing over 80% of those it infects. The antidote doesn’t always work.

When your firsts become infected, you’ll just feel like you have a cold. But after a few more days, you’ll have trouble breathing as the anthrax voraciously eats your lungs and grows in your blood. The anthrax soon reaches the brain and causes it to bleed.  You’ll then lapse into a coma and suffer massive internal bleeding, eventually suffocating to death in your own blood.

Botulism: The bacterium Clostridium botlulinum produces the neurotoxin botulinum, two ounces of which is enough to kill the entire United States. You can get botulism from expired canned food. Botulism kills by slowly paralyzing all of your muscles, so that eventually you can no longer breathe. However, you won’t lose consciousness; as you die from botulism you will be aware of the paralysis overtaking your entire body and feel yourself suffocating.

Ebola: Ebola is probably the worst of all. There is no known cure for ebola, and over 80% of those that contract if die. When you first become infected with Ebola, the symptoms aren’t that interesting: headaches, muscle aches, fever, fatigue, nausea, and dizziness. But after a few days, Ebola will simply start to dissolve your blood vessels, and you will begin to bleed rapidly from every orifice. You eventually die either from organ failure, or the simple absence of enough blood in your body. To this day, no one knows where Ebola comes from, or even how it was initially transmitted to humans.

Source: This Will Kill You: A Guide to the Ways in Which We Go by HP Newquist and Rich Maloof

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If an alien civilization tried to reach out to us, how would they do it? Radio waves are the obvious answer; they travel far and only require a small power input. But what type of radio signal would aliens send?

In the early seventies, physicists Phillip Morrison and Giuseppe Cocconi predicted that an alien civilization would transmit a radio signal at 1420 MHz and in a narrow band frequency. Why? An alien signal would have to be something more fundamental and universal than language, something that any intelligent civilization would understand. So why not use a number associated with the most common element in the universe, hydrogen? Hydrogen emits radiation at 1420Mhz. Furthermore, Morrison and Cocconi predicted that an extraterrestrial civilization would send the signal at a narrow band frequency, as narrow band frequency signals require less energy and are created by no natural phenomena.

On August 15, 1977, an exact match for this signal predicted by Morrison and Cocconi arrived on a detector in Delaware, Ohio. Astronomer Jerry Ehman, who first discovered the signal in the data a little while later, christened it the, “Wow!” signal. It has never been explained since.

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 Recent advances in the biological sciences have made cloning, the production of a genetically identical copy of an organism, a reality. However, not everyone believes that scientists should attempt to clone human beings. Opponents of human cloning present a compelling case. First, they argue that cloning is an inefficient process that would likely produce an unhealthy clone. Furthermore, opponents warn that a clone would unfairly bear heavy psychological burdens. Finally, those against cloning caution that human cloning would be detrimental to society at large. However, those in favor of human cloning raise some valid points. For instance, advocates argue that cloning research may lead to medical benefits. They also make the case that cloning is just another form of reproductive technology that people should be free to use. Despite these arguments in favor of cloning, the negative aspects of human cloning outweigh any positive ones; scientists should not try to clone human beings.

Organismal cloning, the generic term for cloning that produces an entire human, animal or plant from a single cell, first emerged as a technology in 1958 when carrots were cloned from mature carrot cells. Like all clones, the cloned carrots carried the exact same genetic code as the mature carrot cells from which they were cloned (Petechuck). Cloning research continued to make incremental improvements over the next few decades, and in the summer of 1996 scientists accomplished the successful cloning of a mammal for the first time with the birth of Dolly, a cloned sheep, at the Roslin Institute (Nardo 35). Dolly’s birth spawned a media frenzy, and for the first time the public and politicians seriously debated the morality of organismal and human cloning. Shortly after Dolly, in June of 1997, President Clinton called on the U.S. Bioehics Advisory Commission to review the ethical and legal implications of cloning (Human Cloning). The debate on the ethicality of cloning, and specifically human cloning, hasn’t stopped since.

The technology that produced Dolly, and that could also create a human clone, is known as somatic cell nuclear transfer, often abbreviated as SCNT. In SCNT, the nucleus of an egg cell is removed, literally using a glass pipette. This nucleus is then replaced with the nucleus from a cell that contains the genetic material of the organism that is being cloned. Naturally occurring chemicals inside of the egg cell then cause the egg to develop into an embryo, just as it would if the egg had been fertilized naturally by a sperm cell (Sive). However, unlike a normal embryo, the embryo that results from SCNT is genetically identical to the organism that supplied the donor nucleus. In the case of humans, a clone would be a younger identical twin of the individual that had supplied his nucleus.

Though extraordinary, the technology of SCNT contains several peculiarities that create the first objection raised by opponents of human cloning; cloning is an inefficient process that produces physically abnormal clones. First, for reasons that remain obscure, the success rate of cloning experiments in producing organisms is extremely low. In a recent experiment that cloned human embryos through SCNT, only three out of twenty five attempts worked (Caplan). More generally, scientists estimate that the success rate of SCNT hovers around a mere one percent (Sive). Furthermore, animal clones almost always suffer physical problems that normal animals do not. For instance, Dolly suffered from extreme arthritis and lung disease that forced veterinarians to euthanize her at the age of six, when sheep normally live to the age of twelve (Petechuck). In addition to these physical problems, research showed that Dolly possessed DNA that was older than her chronological age. Carrying this older DNA made Dolly more susceptible to age-related illnesses, especially cancer. Old DNA and physical problems similar but not limited to those of Dolly have been observed in a wide range of cloned animals; nearly all clones have something wrong with them (Sive). Consequently, the pattern suggests that a human clone would be difficult to create and suffer many physical abnormalities.

As a consequence of the near certainty that human clones would bear many health problems, opponents of human cloning make the valid point that human cloning cannot be ethically carried out because it exposes clones to physical harm. Though future technology may be able to create healthy clones, the experimentation necessary to create such technology also violates moral principles, as the experimentation would likely produce physically damaged clones (Kaebnik).   Furthermore, regarding human cloning research, the President’s Council on Bioethics concluded that, “There seems to be no ethical way to try to discover whether cloning to produce children can become safe, now or in the future” (President’s). Since human cloning would produce clones with dramatic health problems, and any research that would make cloning safe would also produce babies with health problems, no situation exists where human reproductive cloning should be attempted.

Not only do opponents of human cloning argue that cloning would inflict physical health problems on clones, but they also warn that a clone would suffer psychological burdens to such an extent that cloning a person would be unethical. First, a clone would likely grapple with pronounced problems regarding his sense of identity and self. The President’s Council on Bioethics cautions, “Cloned children may experience serious problems of identity both because each will be genetically virtually identical to a human being who has already lived and because the expectations for their lives may be shadowed by constant comparisons to the life of the ‘original’” (President’s). Also, a clone may feel as if he had been denied an open future, as he would be constantly compared to the person he had been cloned from. Finally, any human clone will have to learn to handle the thought that he is a copy of someone else and not an original person (Wachbroit). Adversaries of cloning make the point that forcing a clone to accept his status as a copy and not his own unique individual fundamentally violates human dignity. Because a clone would have many painful psychological issues to confront, human cloning can only lead to suffering, and thus it should not be carried out.

Though the opposition of cloning makes the case that cloning should not be tried because it would cause the clone to suffer, human cloning also should not be attempted because it would have a detrimental effect on society. For instance, cloning creates the danger that some individuals may be cloned against their will. Since people give off cells everywhere they go, it would be nearly impossible to prevent someone from cloning another individual without that individual’s consent. Fans may try to clone actors or superstar athletes, and a woman could even clone an apathetic man that she wants to have a child with (Herbert). Moreover, human cloning may cause society to look at identity differently. “Cloning might force us to regard people as repeatable, and accepting that people are not one time occurrences is to allow the value of personhood to be diminished” (Kaebnick). Since a society that permits human cloning could not prevent individuals from being cloned without their permission, and also since the value of the person may be reduced, human beings should not be cloned.

While the stronger arguments do not support human cloning, those in favor of cloning raise some valid points. First, advocates claim that research on human cloning and SCNT may produce medical benefits. For instance, scientists may learn more about cellular differentiation, a process that often goes wrong in cancer, if they are permitted to study somatic cell nuclear transfer (Kaebnik). This is a valid point, but it only makes the case for allowing SCNT as a technology; it does not make the case that human beings should be cloned. On a more profound level, supporters of human cloning have argued that cloning is just a new form of human reproduction. “In general, why should a couple using cloning have a higher justification required of them than a couple using sexual reproduction?”(Pence). Likewise, cloning could provide infertile couples their only way to have biological descendants, and the ability to have biological descendants may fall under the rights granted to individuals in modern Western societies (Kaebnik). For instance, if cloning is just the newest form of human reproduction, then it is already protected in the United States by the Constitution (Pence). For the proponents of human cloning, its potential to help the sick, as well as those trying to become parents, is most compelling.

Though proponents of cloning raise substantial points, the arguments against cloning carry the day. Specifically, a clone would suffer immensely. He would be born with many health problems, and he would be forced to wrestle with many heavy psychological burdens. “Once the welfare of the clone is considered, the anti-cloning arguments far outweigh the pro-cloning arguments”(President’s). Furthermore, a society that allows cloning would experience detrimental effects, as it could not prevent cloning without permission and would see the value of personhood diminished. For all these reasons, the technology of cloning should not be applied to people; scientists should not attempt to clone human beings.

Works Cited

“Animal Pharming: The Industrialization of Transgenic Animals.” Center for Emerging Issues.      CEI.  Dec. 1999. Web. Feb. 2010.

Caplan, Arthur. “Human Embryos Cloned:  What does it mean?. MSNBC Health. MSNBC. 17     Jan. 2008. Web. 18 Feb. 2010.

Herbert, Wray, Jeffery Sheler, and Traci Watson.  “Ethical Issues Concerning Human Cloning.”                Contemporary Issues Companion. Ed. Lisa Yount. San Diego: Greenhaven, 2000.                                                                                                      

            129-134. Print. Excerpted from “The World After Cloning.” U.S. News and World.

“Human Cloning.” Issues and Controversies. Facts on File News Services, 29 Dec. 2006. Web.

22.Feb. 2010.

The Human Cloning Foundation. “The Medical Benefits of Human Cloning.” Contemporary        Issues Companion.  Ed. Lisa Yount. San Diego: Greenhaven 2000. 153-155. Print.        Excerpted from “The Benefits of Human Cloning.” 1998.

Kaebnick, Gregory and Thomas Murray. “Cloning.” The Concise Encyclopedia of the Ethics         of the Ethics of New Technologies. Ed. Ruth Chadwick. 1^st ed. Vol.1. San Francisco:          Academic Press, 2001. 51-64. Print.

Mautner, Michael. “Cloning Could Halt Human Evolution.” Contemporary Issues Companion.     Ed. Lisa Yount. San Diego: Greehaven 2000. 141-143. Print. Excerpted from “Will             Cloning End Human Evolution?” The Futurist. Nov. 1997.

Nardo, Don. Cloning. San Diego: Lucent, 2002. Print. Great Medical Discoveries.

Pence, Gregory. “Reproductive Cloning Does Not Demean Human Life.” Cloning: Opposing       Viewpoints. Ed. Tamara L. Raleef.  Farmington Hills: Greenhaven Press, 2006.  22-28.         Print.  Rpt. of “Ten Myths About Human Cloning.” 2001.

Petechuk, David. “Clone and Cloning.” Gale Encyclopedia of Science. Ed. K. Lee Lerner and      Brenda Wilmoth Lerner. 4^th ed. Detroit: Gale Group, 2008. Web. 22 Feb. 2010.

Pinker, Steven. “How the Mind Works.” New York: Norton, 1999. Print.

President’s Council on Bioethics. “Reproductive Cloning Demeans Human Life.” Cloning:           Opposing Viewpoints. Ed. Tamara L. Roleff.  Farmington Hills: Greenhaven, 2006.    16-21. Print. Rpt. of “Human Cloning and Human Dignity.” Presidents’s Council on           Bioethics. New York: Public Affairs, 2002.

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You’ve heard of lung cancer… Breast cancer… Brain cancer… Pancreatic cancer… and cancers of almost all parts of the body. But have you ever heard of muscle cancer? Probably not. Although it does exist, muscle cancer is exceedingly rare and accounts for less than 1% of new cancers in the United States. Why?

Scientists don’t know for sure, but many suspect that muscle cancer is uncommon for a simple reason: muscle cells can store glucose (sugar). Here’s why this matters:

1.      The first mutation that occurs in many cancers is a mutation that causes a cell to take up too much glucose.

2.      The more glucose a cell takes up, the more glucose a cell consumes.

3.      The more glucose a cell consumes, the more waste the cell produces. And unfortunately, a consequence of this waste is the production of reactive oxygen species, commonly abbreviated as ROS.

4.      ROS damage DNA and cause mutation. Eventually, ROS will induce mutations that create uncontrolled cellular proliferation, and cancer will have begun.

However, muscle cells differ from other cell types in a very fundamental aspect. When muscle cells take up extra glucose, they don’t consume it right away. Instead, they store the glucose as glycogen. Consequently, muscle cells have a much lower mutation rate if they are forced to take up extra glucose than other cells have if they consume extra glucose. It is this ability to store glucose as glycogen, instead of burning it and producing mutation inducing ROS, that protects muscle cells from cancer.

Sources:

http://www.canceranswers.com/Muscle.Cancer.html

“Fueling Cancer Cell Growth” Craig Thompson, Ph.D., M.D. Anderson Symposia on Cancer Research 2009

Picture of Global Warming

Everyone worries about global warming these days. As a direct result of humans pumping trillions of tons of carbon dioxide into the atmosphere, global temperatures are predicted to steadily climb, leading to the melting of the polar ice caps by around 2100 (according to the most dire predictions) and a vast rise in sea level that would put modern coastlines under water. The only chance humanity has of halting the progress of global warming is to cap our emission of carbon dioxide, and even then a significant amount of warming will likely still occur (as a result of the CO2 already in the atmosphere). Or is there another option?

There is… geoengineering. Earth scientists have come up with a multitude of ways that people could cool the climate in order to mitigate or prevent the effects of greenhouse gas-induced global warming. In this blog, I’ll focus on the most likely and most cost effective method: sulfur dioxide emission

How It Works:

·         Using commercial planes, military fighter jets, or even giant balloons,  vast quantities of sulfur dioxide would be transported into the stratosphere daily

·         Once in the atmosphere, the SO2 would oxidize to form sulphate (SO4) aerosols

·         Sulphate aerosols are reflexive, so they will reflect some sunlight from the earth and thus cool the planet

·         This concept has already been demonstrated in principle with the Mt. Pinatubo volcanic eruption in 1991. This eruption unleashed a huge quantity of sulfur dioxide into the atmosphere, and global temperatures fell by half a degree Centigrade a year later.

Potential Drawbacks:

·         Although the sulfur dioxide approach would help with global warming, it would do nothing to combat the ocean acidification that carbon dioxide emission is causing

·         The world would need to come to an international consensus before this plan could be put into place

·         Since current climate models aren’t very accurate, there is a very real possibility that humans could overcompensate with the sulfur dioxide and cause too much cooling

·         The view of the stars with underground telescopes would be obscured because of all of the aerosols in the air… KHS Astronomy Club… Bye bye…

·         Solar power would be less efficient

·         Potential drought; the year after the Pinatubo eruption had the lowest rainfall over land ever recorded

Should we geoengineer? The potential problems are real and dangerous. Still, global warming is just as real and dangerous, and geoengineering may be the only way to stop drastic climate change. As time moves on, people will have to weigh the costs and benefits of geoengineering against the consequences of global warming. For instance, which is worse… The drought that would likely be created from sulfur dioxide geoengineering, or the worse hurricanes and rising sea levels that would result from global warming? More importantly, who decides? Thoughts?

Sources:

http://arstechnica.com/science/news/2009/10/weighing-the-pros-and-cons-of-stratospheric-geoengineering.ars

http://www.climateark.org/shared/reader/welcome.aspx?linkid=140354

Superfreakenomics  by Stephen J Dubner and Steven Levitt