What Are Antibiotics Made Of?

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What are antibiotics made of?Drew Smith:

Most antibiotics are based on natural products synthesized by bacteria and fungi. Quinolones (like Cipro) and sulfa drugs (like sulfamethoxazole) are the major exceptions to this rule.

Antibiotics belong to a class of natural compounds called secondary metabolites. These are molecules that are not essential to normal growth and metabolism (like sugars, amino acids, and nucleic acids) but perform specialized roles. Secondary metabolites enable creatures that can’t move or speak to communicate, control their environments and defend themselves.

Bacteria, plants, and fungi are much better than human chemists at creating complex molecules. These biosyntheses are often accomplished in factories within cells, large complexes of enzymes in which various precursors and intermediates are assembled, modified, and passed on.

Vancomycin, the most commonly prescribed antibiotic in U.S. hospitals, is a good example:

Although total synthesis of vancomycin has been accomplished in labs, I believe that it is still produced commercially by fermentation of the bacterium Amycolatopsis orientalis from which it was first isolated.

The thing to keep in mind about these secondary metabolites is that anything that is made by an enzyme can also be broken down by an enzyme—often the same one that made it. Small tweaks to these enzymes, or just putting them in a different environment, can cause them to degrade antibiotics. Antibiotic resistance is thus an intrinsic and inevitable feature of antibiotic use.

This post originally appeared on Quora. Click here to view.

Are Any of the Scientific Instruments Left on the Moon By the Apollo Astronauts Still Functional?

Apollo 11 astronaut Neil Armstrong left the first footprint on the Moon on July 20, 1969.
Apollo 11 astronaut Neil Armstrong left the first footprint on the Moon on July 20, 1969.
Heritage Space/Heritage Images/Getty Images

C Stuart Hardwick:

The retroreflectors left as part of the Apollo Lunar Ranging Experiment are still fully functional, though their reflective efficiency has diminished over the years.

This deterioration is actually now delivering valuable data. The deterioration has multiple causes including micrometeorite impacts and dust deposition on the reflector surface, and chemical degradation of the mirror surface on the underside—among other things.

As technology has advanced, ground station sensitivity has been repeatedly upgraded faster than the reflectors have deteriorated. As a result, measurements have gotten better, not worse, and measurements of the degradation itself have, among other things, lent support to the idea that static electric charge gives the moon an ephemeral periodic near-surface pseudo-atmosphere of electrically levitating dust.

No other Apollo experiments on the moon remain functional. All the missions except the first included experiment packages powered by radiothermoelectric generators (RTGs), which operated until they were ordered to shut down on September 30, 1977. This was done to save money, but also because by then the RTGs could no longer power the transmitters or any instruments, and the control room used to maintain contact was needed for other purposes.

Because of fears that some problem might force Apollo 11 to abort back to orbit soon after landing, Apollo 11 deployed a simplified experiment package including a solar-powered seismometer which failed after 21 days.

This post originally appeared on Quora. Click here to view.

What Makes a Hotel Breakfast 'Continental'?

Hotels often offer a complimentary pastry and fruit breakfast.
Hotels often offer a complimentary pastry and fruit breakfast.
tashka2000/iStock via Getty Images

The continental breakfast, which is typically made up of pastries, fruit, and coffee, is often advertised by hotels as a free perk for guests. But why is it called continental, and why don’t patrons get some eggs and bacon along with it?

The term dates back to 19th century Britain, where residents referred to mainland Europe as “the continent.” Breakfast in this region was usually something light, whereas an English or American breakfast incorporated meat, beans, and other “heavy” menu options.

American hotels that wanted to appeal to European travelers began advertising “continental breakfasts” as a kind of flashing neon sign to indicate guests wouldn’t be limited to American breakfast fare that they found unappealing. The strategy was ideal for hotels, which saved money by offering some muffins, fruit, and coffee and calling it a day.

That affordability as well as convenience—pastries and fruit are shelf-stable, requiring no heat or refrigeration to maintain food safety—is a big reason continental breakfasts have endured. It’s also a carryover from the hybrid model of hotel pricing, where American hotels typically folded the cost of meals into one bill and European hotels billed for food separately. By offering a continental breakfast, guests got the best of both worlds. And while Americans were initially aghast at the lack of sausages and pancakes on offer, they’ve since come around to the appeal of a muffin and some orange juice to get their travel day started.

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