Science Fact, or Science Fiction?

Fact. As unlikely as it sounds, there is a type of animal whose survival relies on this very ability. Tardigrades, also known as water bears, are water-dwelling, microscopic invertebrates that are deemed by many as the “toughest animals in the world” due to their ability to withstand the most extreme of environments. They live quite literally all over the world and can be found from the deep sea (below 4,000 m) to the Himalayas (above 6,000 m), and from the arctic to the tropics. In laboratory studies, they have been shown to endure temperatures from 1 K (-272° C) to roughly 420 K (150° C), pressures up to 600 times that of the surface of the Earth, high intensity ionizing radiation, going without food or water for 10 years, and even the vacuum that is outer space. They can also survive extreme desiccation (drying out) by turning to glass! In a recent study by biologist Thomas Boothby of the University of North Carolina, it was discovered that in dry conditions, tardigrades can make large amounts of particular “glass” proteins. If the water bears are hydrated, these proteins are disordered in liquid solution; however, once water is removed, the proteins form a glass glaze that protects the other proteins and molecules that would otherwise be damaged when dried. The water bear recovers upon the addition of water, which “melts” the glass.

Why should we care (aside from how cool this is)?

This discovery has implications on the food and pharmaceutical industries. For instance, it may allow for the stabilization of proteins in bacteria or cells for extended periods of time without refrigeration. It has also inspired further research into the properties of glasses and the development of a new type of glass.

Sources

To read more about the study: https://www.sciencenews.org/article/water-bears-glass-all-full

More about water bears: http://www.nytimes.com/2015/09/08/science/the-tardigrade-water-bear.html?_r=0

Glass research and practical implications: http://www.uchicago.edu/features/microscopic_animals_inspire_innovative_glass_research/

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Fact.

Biomethane, also called biogas or renewable natural gas (RNG), is produced by the anaerobic digestion of organic wastes such as sewage, manure, and dead plant and animal matter. It can be used as a greener alternative to the conventionally-used natural gas – a fossil fuel – derived from stores of dead plant and animal matter buried deep in the ground for thousands to millions of years. Unlike conventional natural gas, biomethane is a renewable energy source that is not limited to existing stores, and surprisingly reduces the release of methane (a highly potent greenhouse gas) and other harmful gases into the atmosphere. This is because its production eliminates the exposure of decaying matter to the air, preventing the release of gases; whereas naturally-decomposing organic matter causes gases (such as nitrous oxide) to be emitted directly into the atmosphere.

Pictured above is the 40-seater Bio-Bus, the first bus in the United Kingdom to run on gas generated through the treatment of sewage and food waste, which began service in November of 2014. A full tank of gas allows the bus to travel up to 300 km and takes the annual waste of around five people to produce. In addition to powering vehicles, biomethane can function just like conventional natural gas in electricity generation, water and space heating, and cooking. The use of biomethane can be a significant step towards reducing emissions in urban areas and achieving a more sustainable means of fueling transport.

Sources

To read more about the Bio Bus: http://www.geneco.uk.com/About-Us/News.aspx?ID=14

More on biomethane:

http://www.biomethane.org.uk/

http://www.afdc.energy.gov/fuels/natural_gas_renewable.html

http://biofuelstp.eu/biogas.html

http://waste-management-world.com/a/biomethane-fuelled-vehicles-the-carbon-neutral-option

Also, beer-powered cars? – http://www.nationofchange.org/2015/08/04/are-we-ready-for-beer-powered-cars-new-zealand-thinks-so/

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Fiction.

It’s a frequently-used piece of “common knowledge” in classrooms and scientific literature, but the idea that bacteria cells typically outnumber human cells in the human body in a 10:1 ratio does not have much scientific basis. New calculations from January 2016 find that there are instead roughly equal numbers of each: a standard “reference” man weighing 70 kg would be composed of 40 trillion bacteria and 30 trillion human cells – a ratio of 1.3 bacteria cells for every 1 human cell. As red blood cells form the majority of human cells in the body, and women tend to have lower blood volumes than men, women may have about 30% more bacteria per human cell than men do; however this is still far off from the old 10:1 estimation.

So where did the 10:1 idea come from?

The 10:1 ratio of bacteria cells to human cells stems from a 1972 paper which contains a very rough estimation derived from combining values from various pieces of scientific literature. When these values were revisited, it was found that simplifying assumptions were made that resulted in very different numbers of bacteria in the colon from current estimates. Thus, although the most recent study is yet to be confirmed by other scientists, the true (fluctuating) ratio of bacteria to human cells in the body is likely much closer to 1:1 than 10:1.

Sources

https://www.sciencenews.org/article/body%E2%80%99s-bacteria-don%E2%80%99t-outnumber-human-cells-so-much-after-all?tgt=nr

http://biorxiv.org/content/biorxiv/early/2016/01/06/036103.full.pdf

http://www.nature.com/news/scientists-bust-myth-that-our-bodies-have-more-bacteria-than-human-cells-1.19136

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Fact.

The manchineel tree is an endangered flowering, fruit-bearing tree native to the tropical regions of southern North America and northern South America. The tree’s leaves and fruits deceptively resemble those of an apple tree; however mistaking it for an apple tree and eating its fruit calls for a particularly unpleasant experience. Excruciating abdominal pain, vomiting, bleeding, digestive tract damage, difficulty breathing and seizures are just some of the effects one can experience after taking a bite out of what was called the “death apple” by early explorers. Merely touching the tree’s bark can cause chemical burns, and the smoke created from burning the bark can severely irritate the eyes and cause temporary blindness. A cocktail of toxins, including hippomanin A and B, as well as some as of yet unidentified toxins, is the cause of these effects and can be found in every part of tree – including the bark and the sap. The manchineel tree is considered the world’s most dangerous tree by the Guinness World Records.

Despite its toxicity, there are species known to live among the tree’s branches and eat its fruit, such as some species of iguanas. Additionally, people have also been using the manchineel to build furniture for centuries, neutralizing the sap by drying out chopped pieces of wood in the sun. Indigenous peoples have also long used the tree for various medicinal purposes. Regardless, if you ever find yourself on a tropical island in the Americas, this is definitely a tree you want to avoid.

Sources:

http://www.sabapark.org/downloads/SCF%20Manchineel%20Advisory.pdf

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1127797/

http://www.mnn.com/family/protection-safety/blogs/why-manchineel-might-be-earths-most-dangerous-tree

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Fiction.

Although confusing predators is one of the hypotheses for why zebras have stripes, recent studies strongly suggest that it has more to do with maintaining cooler body temperatures and repelling flies than with camouflage. Since black absorbs more heat than white, air currents over the black parts of a zebra are more rapid and stronger than those over the white parts. This leads to what are called “cooling eddies”: the meeting of the two opposing air flows causes air to swirl and cools down a zebra’s skin. There was evidence that in the same area, other animals without the stripes had skin temperatures a whole three degrees Celsius higher than zebras. In addition, zebras who live in colder climates were found to be less striped (lacking stripes in legs and/or other body parts) than those in hotter climates. Disease-carrying flies are also likely to avoid black and white surfaces; hence the stripes may be behaving as a form of natural bug-repellent, reducing the zebra’s exposure to potential diseases.

Sources

Find out more in the links below:

http://newsroom.ucla.edu/releases/why-do-zebras-have-stripes

http://news.nationalgeographic.com/news/2015/01/150113-zebras-stripes-evolution-animals-science-africa/

http://blogs.discovermagazine.com/d-brief/2014/04/02/why-do-zebras-have-stripes-riddle-finally-solved/#.VpRckBUrLIU

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