Tag Archives: medicine

Who said you can’t see bright stars in the deep ocean?


Euprymna scolopes by MattiasOrmestad

A photo of a Bobtail squid,  Euprymna scolopes, performing bioluminescence. It’s underside is brightly lit by its symbiotic bacteria V.fischeri. Photo by Mattias Ornestad on kahikai.org

Euprymna scolopes, commonly known as the Bobtail squids, are found around the Hawaiian Islands. Additionally, they’re about 4.5cm and has one other amazing fact: they have an indirect ability to perform bioluminescence, which is the production or emission of light by living organisms.  To be exact, the Bobtail squids don’t produce this phenomenon, it is the bacteria residing in these squids that produce this light. Together they can perform the largest symphony of dancing blue stars in the ocean.

The bacteria, Vibrio fischeri, is a symbiont that lives in the mantle of the Bobtail squids. The squids acquire this bacteria after they are hatched. These symbionts live in the deepest tract of the mantle and they produce the light source depending on the seawater environment, sensed through the squids’ pores. Furthermore, the Bobtail squids expel around 90-95% of these bacteria every dawn. At dusk, the bacteria increase in population and emit light again from the mantle. Since Euprymna scolopes is a nocturnal species, it hunts for prey at night time. With the bacteria, the squids are able to perform counterillumination. This effect allows them to camouflage themselves by looking like the sky above or deep abyss to divert their predators’ attention.

Here’s a video from the United Kingdom Society for Applied Microbiology uploaded by Siouxsie Wiles on YouTube. It explains how the Bobtail squids and the bacteria interact.

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But here is the most astonishing hypothesis about the symbiotic relationship: the squids themselves can adjust the intensity of the light produced by their dependents.

Research tested this hypothesis and found two possible theories. Firstly, the squids may be controlling their oxygen intake to restrict the bacteria’s production of energy, thus resulting in dimmer or brighter illumination.  Secondly, the squids control light emission by using their ink sac as an iris to restrict light. Both processes cannot kill the bacteria but only limit its emission. Unfortunately, biologists couldn’t explain the mechanism behind light intensity control since they could not visually see inside the mantle.

Aliivibrio fischeri (toxita.cz)

A photo of the bacteria, Vibrio fischeri, which provides the Bobtail squid bioluminescence, in a petri dish. Photo from toxita.cz.

Biologists are trying to find out how these bacteria communicate with its host. There still remain many unanswered questions. For example, how do the squids know how much V. fischeri to expel? What happens if we remove these symbiotic bacteria from their hosts? How do the squids know when to stop before killing the bacteria?

With further research, they hope to understand how bacterial cells communicate with human cells using Bobtail squids as their model. Scientists wish to find ways to distinguish harmful bacteria versus those that help regulate our body. By understanding how V.fischeri functions inside the squids, we could produce antibiotics that only pinpoint the harmful bacteria in our body and find ways to disrupt these bacteria from causing us sicknesses.

– Alison Fung





Miracle Cures? Not Quite.

Hey, remember that miracle baby that was found to be HIV-free?

No? What about the HIV-killing bee venom?

How about the cure for all cancer, courtesy of you friendly neighbourhood mole-rat? They all sound so promising, don’t they? All the talk with “foresee[ing] a day when the … treatment could give … a lifetime free of toxic and costly antiviral drugs”  and “radically and potentially life-saving treatment[s]“.  At this rate, it sounds like the new “wonder-drugs” are just around the corner;  and when they hit the pharmacies and hospitals, the world will be a much, much better place.

So where’s the cancer drugs? Why aren’t pharmaceutical companies scrambling to raise beehives to harvest bee venom? And why are doctors still prescribing antivirals to HIV+ patients? What happened to those “major breakthroughs” and “game-changers”? To make a long story short, science doesn’t work like that. The science behind new drugs is a well-tested and extensively researched, and it follows a rigorous process.

LONG ROAD TO A NEW DRUG” by Lizanne Koch – own work. Via Wikibooks.








The development of a new drug begins with a breakthrough in research – things like a new therapy target, or a new way of treating a condition. A classic example of this is the key development in HAART therapy towards controlling the HIV virus, as shown in the video in detail.

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After first observing AIDS in the US in 1981, it took two years for researchers to confirm the source of the symptoms as the HIV virus in 1983, and another 4 years for the FDA to approve azidothymidine/AZT,  one of the first antiviral drugs effective against suppressing HIV. The video describes the molecular mechanism of AZT:

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Of course, AZT was ripe with side-effects; it took until 1991 for researchers to find effective antivirals which minimized the side-effects.  The entire process to develop today’s HAART took just over 10 years  – hardly “around the corner”. And this is a process repeated by many of the novel drugs proposed in academia  – it takes DECADES, if not years to develop a drug that is safe and effective.

So, where do all those “break-throughs” fit in? Well… That’s the thing. Even though science makes discoveries in cutting-edge fields on a daily basis, it takes months, if not years of follow-up experiments to confirm the results. Adding this to the arduous process of drug development, it may be a long, long time before a viable drug is developed, assuming the new proposed drug holds up in the experiments and the clinical trials. Of course, one can only hope that the breakthrough doesn’t turn out to be a false-positive, like the (ex-)HIV-free baby.

As for the daily media sensationalist titles, they may sound hopeful and optimistic (not to suggest that they’re not), but the point is to take them with a grain of salt. After all, a disease takes years to be understood scientifically, and longer still to develop a working treatment. And of course, always remember:

source: XKCD

Souce: XKCD

– James L.