Tuesday, July 21, 2015

Living Off Nothing But Coffee

Can you imagine living off nothing but coffee? Some of us probably feel like we do at times, if not for the taste then for the buzz the caffeine brings. Caffeine makes us feel more alert because it structurally resembles a molecule called adenosine.
Caffeine and adenosine are like brothers from another mother.
 Adenosine accumulates in our brain the longer we stay awake, binding to its receptors to induce that sleepy feeling we all get after a long day. It is the body’s way of signaling to the brain that it has had enough and needs to shut down for a while. If you disagree with your body, the ingestion of caffeine can help. Due to their structural similarity, caffeine competes with adenosine for binding to adenosine receptors; however, adenosine receptors do not execute the signal to shut down when bound to caffeine. In other words, the body is trying to throw a pass to sleep but caffeine blocks the receiver.

Some people can’t get to their happy place without a cup of joe in the morning. By the way, the term “cup of joe” is likely to have originated from “cup of jamoke” - “jamoke” being a combination of locales noted for their coffee goodness, “Java” and “Mocha”.
But that’s not all. Caffeine also ramps up adrenaline production, which increases your heart and breathing rates, and primes your brain and muscles for action. You feel a boost from coffee because the caffeine blocks the signal to sleep and fools your body into thinking it is under attack.
Like other drugs, people can build up a tolerance to caffeine, requiring more and more of the drug just to achieve the sensation of that original buzz. And the road to addiction is a short one, indeed. People love their coffee so much that the threat of a shortage can send them into a panic, which is perfectly captured in this scene from Airplane II.


How much coffee can people safely consume? According to the FDA, 400 mg (4 cups of brewed coffee) per day appears to be safe for most healthy adults. While it is estimated to take about 140 cups (8 oz size) of coffee to kill, you can get there a lot quicker with pure caffeine powder. A single tablespoon can be lethal, prompting the FDA to issue this warning to consumers.

But there is a creature on Earth that can tolerate much, much more. In fact, it eats coffee beans for breakfast. And lunch. And dinner. And everything in-between. Amazingly, the coffee berry borer eats nothing but coffee beans!

The coffee berry borer is a small but devastating beetle that lays waste to coffee crops. It subsists solely on coffee, capable of drinking any Starbucks junkie under the table.

Scientists have recently discovered how the coffee berry pest can tolerate toxic levels of caffeine. Do they possess a special gene that can detoxify caffeine? Do they have receptors that don’t bind caffeine? No…evidently, the answer does not lie in the genome of the beetle, but in its gut.
Like most other living creatures, the coffee berry borer houses a microbiome in its intestinal system. Several species of bacteria, such as Pseudomonas fulva, that reside in the gut of coffee berry borers are wizards at breaking down caffeine. The gut bacteria from coffee berry borers found around the world were put into culture medium containing caffeine as the primary nutrient so researchers could identify which species grew the best in this condition. P. fulva was the most common; subsequently, this bacterial species was found to carry a gene known to degrade caffeine.

To further test this hypothesis, researchers gave the beetles antibiotics to deplete their intestinal microbiome. Beetles without their gut bacteria lost the ability to break down caffeine. When fed some P. fulva before their coffee bean diet, the beetles excreted no caffeine, indicating that they were able to detoxify it once again.

Assuming no adverse effects, ingestion of P. fulva might help humans break down caffeine. A better alternative to decaf?
The scientists speculate that altering the beetle’s microbiome might provide a new approach in the battle against this pest. However, antibiotics are a precious commodity in treating human disease, so this could be a reckless idea as the introduction of antibiotics into the field has the potential of generating resistant bacteria.

From an evolutionary perspective, the study serves as an example of how organisms can adapt to a new niche without genetic modification. By acquiring specific types of bacterial symbionts, the coffee berry borer is uniquely able to live off nothing but coffee.

In the video below, you can learn more about this research and similar studies being performed at Lawrence Berkeley National Laboratory:

Contributed by:  Bill Sullivan
Follow Bill on Twitter.

See the news release at ScienceDaily.
Ceja-Navarro, J., Vega, F., Karaoz, U., Hao, Z., Jenkins, S., Lim, H., Kosina, P., Infante, F., Northen, T., & Brodie, E. (2015). Gut microbiota mediate caffeine detoxification in the primary insect pest of coffee Nature Communications, 6 DOI: 10.1038/ncomms8618

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