Lunar Oasis

A QUANTUM OF SCIENCE

Three separate space probes find spectral evidence of lunar water

In October 2008, India launched the Chandrayaan-1, its first lunar probe. The Chandrayaan-1 was designed to spend the following two years mapping the surface of the moon, but on August 31, 2009 contact with the probe was lost. Before then, however, the probe generated over 70,000 high-resolution images covering almost the entirety of the moon’s surface. Even more importantly, its sensors revealed a curious observation: ice.

Light absorbance is the characteristic interaction of different wavelengths of light with particular chemical elements. If a specific element is present in a material, it will absorb light of a characteristic wavelength. The same is true for simple compounds, such as water. With this technique, specific elements and often simple compounds can be detected even at interstellar distances, allowing scientists to deduce the chemical composition of distant stars. One compound that has a particularly characteristic absorbance spectrum is water. The Chandrayaan’s sensors reported a spectrum containing absorbance peaks consistent with water, and soon afterwards the observations were repeated by NASA’s Cassini and Deep Impact space probes.

Isn’t the moon a dry desert, though? Apollo astronauts certainly believed so when they landed on the moon in 1969, and "moon rocks" brought back from the lunar landing seemed to confirm it – except that it was assumed that any humidity found in the samples were the result of earth water contamination. Now, scientists theorize that water exists on the lunar surface in extremely thin layers just millimeters below the surface. The source and amount of water are still matters for further investigation, but scientists theorize that water on the surface of the moon might "migrate" as the moon is alternately warmed and cooled by exposure to the sun, until it ends up in deep lunar craters. These craters were recently found to be at a lower temperature than the surface of Pluto, so water ending up there would be "stuck" and accumulate over time.

The existence of water on the moon is particularly exciting not only because it was contrary to decades-old assumptions but also because it creates new possibilities. If it could be effectively harvested, lunar water could help sustain a human outpost on the lunar surface. Even more daringly, some have suggested that hydrogen and oxygen derived from electrochemically "splitting" this water could serve as rocket fuel. Rockets launched from the moon would require substantially less fuel because the moon’s gravity is so much less than that on Earth, leading to speculation that lunar launches could facilitate a new era in the exploration of the solar system, especially Mars.

For more information:

India's first lunar probe fails after less than a year (New Scientist)

Widespread water may cling to moon's surface (New Scientist)

How astronauts could 'harvest' water on the moon (New Scientist)

What Do Spectra Tell Us? (NASA)


© AQOS / P. Smalley (2009)
Reproduction with attribution is appreciation

Gene Therapy cures color-blindness in adult primates

A QUANTUM OF SCIENCE

This is the single biggest success story for gene therapy to date. Instead of reiterating, I will simply say: go read the linked articles and marvel that this could have come to pass in your lifetime.

"Looking back on this in 50 or 100 years, it will be a landmark paper even then."
-David Williams, director of the University of Rochester’s Center for Visual Science

FOR MORE INFORMATION:

Gene Therapy Cures Color-Blind Monkeys (Wired Science)

Original article: Gene therapy treatment of color blindness in adult primates (Mancuso et al)


© AQOS / P. Smalley (2009)
Reproduction with attribution is appreciation

Antioxidants Curb Cancer's Spread

A QUANTUM OF SCIENCE

New research shows reactive oxygen breaks down cell walls and helps cancer spread

Malignant cancer tumors have a unique characteristic: they can release tumor cells into the lymphatic system and cause tumors to grow elsewhere in the body, even in tissues or organs totally unrelated to those that were the original source of the tumor. This process is called metastasis, and sometimes forces doctors to use whole-body or systemic anti-cancer treatments when a localized treatment targeting a single tumor would be both more effective and far easier on the patient. Now scientist are advancing understanding of how metastasis occurs, and how to prevent it.

Researchers at Burnham Institute for Medical Research in La Jolla, California recently reported that reactive oxygen species were key players in the cellular process of metastasis. Reactive oxygen species (ROS) include superoxide, hydrogen peroxide and other forms of oxygen generated by the body’s normal functions. Some uses of ROS are beneficial, such as when the immune system generates ROS to kill invading cells. In cancerous cells, however, ROS help form lesions and break down cell walls, aiding in the spread of tumor-forming cells. Researchers have isolated a scaffold protein called Tks5 (for Tyrosine Kinase Substrate) which is concentrated in extruded lesions of tumor cells, called podosomes (or invadopodia in some papers). Tks5-rich cells rapidly produce ROS and form lesions that facilitate the spread of tumorous cells throughout the body. In their paper, Burnham scientists show that cells lacking the gene for Tks5 production are substantially inhibited from forming metastatic tumors, and treating the tumor cells with antioxidants similar suppresses the activity of Tks5, resulting in smaller tumors, fewer lesions/podosomes and a substantial decrease in extruded (metastatic) cells.

An example of tumor size reduction in cells lacking the Tks5 gene (4.20 and 4.24):

This paper is an exciting advance in the understanding of the basic processes of malignant cancer. If podosome formation and metastasis can be reduced by either antioxidant treatments or drugs that target Tks5, huge advances can be made in reducing the mortality associated with highly-metastatic malignant cancer.

For more information:

Reactive Oxygen’s Role in Metastasis

A role for the podosome/invadopodia scaffold protein Tks5 in tumor growth in vivo (Blouw et al)

Metastasis (Wikipedia article)

© AQOS / P. Smalley (2009)
Reproduction with attribution is appreciation

Old Flu Drug, New Hope

A QUANTUM OF SCIENCE

When vaccines fail, antiviral drugs might make the difference between life and death

The seasonal flu vaccine is already being administered and a special vaccine targeting H1N1 will soon follow, but for some people a vaccine may not be enough. Children, the elderly and immunocompromised individuals are at high risk for complications from influenza. For those already infected a vaccine does no good, but fortunately, antiviral medications are available when the flu turns life-threatening.

The most well-known anti-influenza drug is TamiFlu (its official name is Oseltamivir). TamiFlu is taken orally, usually for a five-day course of treatment. Approved in 1999, it has been used to treat 50 million people to date. Currently, TamiFlu is usually reserved for serious, potentially life-threatening cases in an attempt to prevent the flu virus from mutating into a form resistant to the drug. Indeed, five cases of TamiFlu-resistant H1N1 have already been reported but overall the rate of resistance flu cases remains low (around 1.2%).

Recently, a drug called Peramivir has been developed and is on the fast track to approval by the FDA. This is not a new drug – it was abandoned in 2001 by Johnson and Johnson due to low oral availability – but in 2005 concerns over Avian flu caused drug-makers to reexamine the compound and begin testing it as an intravenous medication. Recent studies show a single intravenous dose of Peramivir is as effective as the full five-day course of oral treatment with TamiFlu. Additionally, adverse drug reactions were less common with Peramivir.

Both TamiFlu and Peramivir act by inhibiting the same viral enzyme, neuraminidase. This enzyme allows viral particles to escape infected cells and go out in the bloodstream where they can find new cells to infect. When TamiFlu or Peramivir inhibit the viral neuraminidase, viral particles remain trapped inside infected cells until the body’s immune system can respond, usually with macrophages (literally "big eaters") that engulf the infected cell and digest it, destroying the viral particles along with the cell.

Additional advantages of Peramivir include its single-dose effectiveness. There have been reports of individuals hoarding TamiFlu pills and threatening the supply of the drug, but that cannot happen with a drug which can only be administered intravenously.


For more information:

Study: New Drug Fights Flu as Well as TamiFlu

TamiFlu (Wikipedia article)

TamiFlu-resistant H1N1 cases reported


© AQOS / P. Smalley (2009)
Reproduction with attribution is appreciation

Toward Better Vaccines

A QUANTUM OF SCIENCE

Making vaccines both optimally effective and optimally safe may be an easier task in the near future

Vaccines have an overwhelming track record when it comes to preventing illness, and thanks in part to conservative rules put in place by the federal agencies regulating them vaccines have also been extremely safe. Still, there’s an unadvertised trade-off in that compromise: vaccines would be even more effective than they are today if they could be made with heat-inactivated pathogens rather than highly purified microbial proteins generated in non-toxic bacteria, but that elevates the risk of possible immune reactions and side effects in those who take the vaccine.

To help improve the effectiveness of vaccines even when not using the heat-inactivated pathogens, scientists have long used compounds known as adjuvants to "boost" the body’s immune response. In essence, adjuvants are sensitizers that tell the body to be ready for an invader; when given as part of a vaccination, adjuvants significantly increase the vaccine’s protective effects both in duration and potency. But the only adjuvant ever approved for use in humans, aluminum hydroxide (or alum), is far from the most effective compound for the job. To date the FDA has been extremely reluctant to approve other, more powerful adjuvants for use with vaccines because of concerns about toxicity and possible side-effects.

Now scientists at Oregon State University have developed an adjuvant based on lecithin, a common food product, that shows six-fold greater immune response when administered as part of a vaccine as compared to alum-based treatments. Lecithin is part of a category of food products termed "generally recognized as safe" by the FDA, meaning that it is non-toxic in almost any dosage. This could mean a fast track to approval and, very possibly, vaccines that would be more effective, for longer periods of time, with smaller doses and fewer injections.

For more information:

New adjuvant could hold future of vaccine development

Adjuvant (Wikipedia article)

Strong antibody responses induced by protein antigens conjugated onto the surface of lecithin-based nanoparticles (Sloat et al)


© AQOS / P. Smalley (2009)
Reproduction with attribution is appreciation

A Weed No Longer

A QUANTUM OF SCIENCE

Latex production finds an unlikely source: dandelions

Latex is a complex emulsion of proteins, alkaloids, starches, sugars, oils, tannins, resins, and gums. In most plants, latex is white, but some have yellow, orange, or scarlet latex. Latex rubber comes from rubber trees, mostly found in South America, where industrial production of this common material has been severely impacted by fungal infections that threaten the entire industry.

The alternative? Dandelions.

The milky white juice that comes out of the stem when picked is a latex not unlike that found in rubber trees, except that it polymerizes immediately on contact with air. With some careful genetic work, scientists have developed a strain of dandelions lacking the enzyme that causes that polymerization, leading to the very real promise of industrial dandelion latex farms in the next five years. The best part of all is that latex from dandelions exhibits none of the immune rejection observed in latex rubber products, making it safe for use by hospitals and other important applications.

Dandelions: a weed no longer.

For more information:

Dandelion’s natural latex now used for rubber production

Latex (Wikipedia article)

© AQOS / P. Smalley (2009)
Reproduction with attribution is appreciation

Quantum: Tree Power!

A QUANTUM OF SCIENCE

"Green power" takes on a whole new meaning

Researchers at the University of Washington have discovered a way to "tap" the small but renewable electrical currents found in trees by investigators at MIT in 2008. Usually these microcurrents (200 millvolts or less) would be incapable of running even small circuits, but electrical engineers from the UW have built special "boost converters" that take a low incoming voltage and store it to produce a greater output.

This is an entirely new and very exciting field where much is currently unknown but the potential exists for a wide range of low-voltage devices that might one day help with everything from early wildfire alerts to climate-change sensors to methods for measuring tree vitality.

For more information:
News article from the UW

Source of Sustained Voltage Difference between the Xylem of a Potted Ficus benjamina Tree and Its Soil (Love et al, 2008)


© AQOS / P. Smalley (2009)
Reproduction with attribution is appreciation

Genetic Pastorale

A QUANTUM OF SCIENCE

Are cows responsible for the spread of a gene allowing humans to digest their milk?

Lactase is an enzyme that breaks down lactose, the disaccharide found in cow milk, into glucose and galactose.



This is important because lactose itself cannot serve as a source of energy for the human body, but glucose and galactose can. The gene encoding lactase can have either one or two copies and still produce enough lactase for carriers to process milk – humans lacking a copy cannot digest cow milk and are called lactose intolerant. Another term, "lactase persistence," refers to the strange stubbornness of the lactase gene, which is inherited in some human populations with far more frequency and fidelity than in other human populations.

Now a new publication shows statistical attempts to model the spread of lactase persistence in European populations as a correlate with how common dairying – raising cows for their milk – is in that region over the last, say, ten thousand years.

While it might seem intuitively obvious that intensive dairying would provide a strong selective pressure for a gene that makes cow milk digestible, this model shows exactly how strong that pressure is. Think about it this way: dairy cows were first domesticated around 9,000 years ago in the early Neolithic age. Since then, their presence has managed to exert a strong influence on human genetics, making those who raise them and care for them much more able to benefit from their milk. Before cattle were domesticated for milk (as opposed to for meat) there was little advantage for humans to possess even a single copy of the lactase gene; today, there is a sharp genetic profile between human populations associated with dairying and those that are not. This map, taken from the statistical modeling publication, shows how sharp that genetic profile is.



Researchers suggest, based on this model, that lactase persistence originated somewhere in the red area on the map around 7,500 years ago. This matches archeological evidence as well, showing the value of the model for predicting genetic drift over time and distance.

As much as human civilization has impacted the genetic destiny of the cow, the reverse is true as well. This begs the question: how many other creatures in our environment are shaping us, even now? It is easy to believe that Homo sapiens is the apex of the evolutionary ladder, but even the humble cow has some say in our genetic path.

For more information:

The Origins of Lactase Persistence in Europe (Itan et al)

Lactase (Wikipedia article)

Lactose intolerance (Wikipedia article)



© AQOS / P. Smalley (2009)
Reproduction with attribution is appreciation

Cut, cut, cut

A QUANTUM OF SCIENCE

Are HIV rates in the US substantial enough to merit a policy of circumcision?

Following evidence of the protective effect against HIV infection, recent news articles report that the CDC is mulling the idea of endorsing circumcision for all male infants born in the United States. But will it have that much impact?

First, the science: how does circumcision prevent HIV infection? HIV infections occur when the virus gains entry to cells by binding to a protein called CD4, found on the surface of cells. Cell types rich in CD4 are thus easier targets for a successful HIV infection. One such cell type is the Langerhans cell, a part of the primate epidermal tissue related to defending the body against invading microbes. As it happens, primate foreskin is rich in Langerhans cells, meaning plenty of CD4 protein for the AIDS virus to bind to and invade the body. By removing the foreskin through circumcision, an easy point of entry for the virus is blocked.

(Interestingly, CD4-rich Langerhans cells are found in human foreskin and vaginal tissues, but not in oral or rectal tissues. This suggests that HIV infections use a different biochemical route when introduced into the body through those tissues.)

The idea of reducing the risk of contracting HIV through circumcision is far from new. In 1987 a letter was published in the New England Journal of Medicine suggesting exactly that, and studies done in the last fifteen years bear out that theory. While the methods used and areas studied (largely in Africa) varied, the conclusions were so striking that in at least one case a circumcision/HIV infection study was halted years early so the findings could be considered for public policy discussions. Depending on the area studied and the risk factors of those involved in the study, HIV infection rates were found to be as much as 50% lower among circumcised African men than their intact counterparts. Various attempts have been made to expand the conclusions of individual studies through meta-analysis papers and their conclusions found an even greater protective effect of circumcision when those studied were from high-risk populations.

So why not support a policy of encouraging circumcision in the United States? The same studies being reviewed by the CDC have some counterindications that are well worth considering in any kind of policy discussion.

First, the benefits of circumcision are greatly enhanced among high-risk populations. This means that for the average American man (whose risk is far, far lower than the average African man) the benefits are considerably lessened. This could well have something to do with the fact that an estimated 79% of American men are already circumcised – though as rates of circumcision have fallen to around 65% in the most recent surveys, that number is now trending downward. Secondly, use of barrier protection is far more prevalent in America among all demographics, another factor that reduces the positive impact of circumcision protection. Another risk factor related to the need for additional preventative measures against HIV infection – the rate of STDs causing lesions or ulcers, such as herpes or syphilis, which help HIV enter the body during sexual contact – is lower in America than in most African nations, and treatment for those afflictions is considerably more available. Finally, almost all the research done in this area has been performed in Africa. This means there is a possibility that things could be different among Caucasian populations, simply because they are biochemically distinct from non-Caucasians.

The need for additional research is clear. Until scientists can repeat the highly successful African studies in America, Europe, or ideally both – since circumcision is much less common in European nations than in America – the benefits of circumcision for Western populations will remain a question too open for a substantive policy debate to take place.


For more information:

CDC mulls routine circumcision of infants to reduce spread of HIV (NY Daily News, 25-Aug-09)

Circumcision and heterosexual transmission of HIV infection to men. (Fink, 1987)

Comparative investigation of Langerhans' cells and potential receptors for HIV in oral, genitourinary and rectal epithelia. (Hussain, 1995)

Male circumcision and risk of HIV infection in sub-Saharan Africa: a systematic review and meta-analysis. (Weiss, 2000)

Male circumcision for HIV prevention in young men in Kisumu, Kenya. (Bailey, 2007)

Langerhans cells.


© AQOS / P. Smalley (2009)
Reproduction with attribution is appreciation

Comets: Interstellar Johnny Appleseeds?

A QUANTUM OF SCIENCE

Are comets the disseminators of the seeds of life?

It was January 2, 2004. The NASA space probe known as Stardust passed through the tail of the Wild-2 comet, five years after the craft was launched on its mission to collect interstellar dust and particle samples from the tail, or coma, of the comet – particles that might well come from beyond Earth’s solar system. A specially-designed collector called an extra low density aerogel was used to capture the particles, and the probe’s camera took high-resolution images of the comet’s nucleus.

On January 15, 2006, the Stardust probe returned to Earth. A sonic boom and a fireball heralded its return over Utah’s Great Salt Lake desert. It was travelling at almost 29,000 miles per hour – the fastest re-entry speed into Earth's atmosphere ever achieved by a man-made object.

Since then, scientists in the Stardust Mission of NASA’s Jet Propulsion Laboratory have been hard at work analyzing the microscopic dust and particles it collected on its seven-year, three billion mile journey. And the results of that analysis are breathtaking.

Some things were expected. Silicate crystals had been predicted based on spectroscopic observations, but their presence confirmed not only those predictions but also the belief that the comet contained matter from outside the solar system.

Even more exciting, organic materials were detected. Astrobiologists have long been aware of aliphatic hydrocarbons (long chains of carbon and hydrogen) diffused throughout space, but the hydrocarbons found in the coma of Wild-2 were much longer than standard interstellar chains, indicating greater complexity. Methylamine and ethylamine, while simple molecules, were an exciting find as well because the nitrogen they contain is essential for life.

But on August 16, 2009, Dr. Jamie Elsila of NASA's Goddard Space Flight Center in Greenbelt, Maryland announced something astonishing. Scientists analyzing the Stardust samples had detected the presence of glycine, the simplest amino acid – and one of the critical building blocks of almost all life on Earth.

Rigorous testing was required in order to confirm this result. Every effort was made to ensure that "earth grime" did not contaminate the samples. The Johnson Space Center in Webster, Texas maintained the comet particles (it is also the home of most of the moon rocks recovered by the Apollo missions) and over 150 scientists from some of the most prestigious laboratories in the world helped with the analysis.

Among the tests they performed as confirmation of the results was an isotopic analysis. Isotopes of an element contain different numbers of neutrons than the most common version of that element, and the prevalence of different isotopes of a given element are well characterized. Using that information, scientists were able to confirm that the isotopic prevalence found in the glycine detected in the comet particles was not terrestrial contamination.

Where did the glycine come from, then? Theories abound, but the one with the greatest antiquity is the theory of panspermia (also known as exogenesis). First proposed in ancient Greece, many respected scientists since the Renaissance have expressed support for the idea that life came to Earth from outer space. This is one of the core areas of study in the field known as astrobiology, a multidisciplinary science that has existed formally since NASA established the first astrobiology program in 1960. Combining physics, astronomy, chemistry, biology and even more specialized sciences, astrobiology concerns itself with the study of the origin, evolution, distribution, and future of life in the universe.

The presence of even the simplest amino acid in the tail of a comet is a profound piece of evidence supporting the idea of panspermia. If this theory is correct, comets might well be the Johnny Appleseeds of the universe, slowly sowing their seeds of complex pre-biotic molecules throughout the galaxy – and suggesting that life on other worlds may be far more common than scientists once thought.

For more information:

NASA article on the discovery
http://www.nasa.gov/mission_pages/stardust/news/stardust_amino_acid.html

SCIENCE Magazine article on Wild-2 analysis (2006)
http://xray.physics.sunysb.edu/research/pdf_papers/2006/sandford_science_2006.pdf

More on the Wild-2 comet
http://en.wikipedia.org/wiki/Comet_Wild_2

More on Panspermia
http://en.wikipedia.org/wiki/Panspermia

More on Astrobiology:
http://en.wikipedia.org/wiki/Astrobiology

© AQOS / P. Smalley (2009)
Reproduction with attribution is appreciation