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In a Dragon’s Blood, Scientists Discover a Potential Antibiotic (nytimes.com)
97 points by dnetesn on April 18, 2017 | hide | past | favorite | 43 comments

More then 5000 antimicrobial peptides (AMPs) have been discovered to date, the first one (gramicidin) back in 1939.

This review article provides a good overview of different AMPs and the history of their discovery: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3873676/

I sincerely hope they are able to synthesize this, and that the synthetic doesn't lose any effectiveness over the natural compound. It sounds like an amazing breakthrough if it works out, as it's much more than a garden-variety antibiotic. FTA:

"It punched holes in the outer membranes of both gram-negative and gram-positive bacteria, it dissolved the biofilms that glue bacteria together, and it sped skin healing."

Getting through the cell walls of gram-negative bacteria alone would make this worth investigating, but the other two added to it are like icing on the life-saving cake.

FTA the mouse trials were done on synthetic peptides already.

Not to take anything away from the accomplishment (we definitely need more research on antibiotics), but the wound healing experiment is IMO just sloppy: they compared a infected wound treated using the peptide to an untreated wound. I could imagine that even a basic wound desinfection using rubbing alcohol will have comparative results to this peptide.

Depends what question you're trying to answer.

If the question is "Is this the greatest antibiotic ever", well, sure you'll want to compare it against a slew of other compounds. But if your question is "does this increase the speed of healing at all?" as a first test before later, more complex experiments, then this seems fine to me.

As far as I'm aware, alcohol or other disinfectants slow healing as they damage tissue. Flushing with water is much better.

Gram + bacteria have no outer membrane.

The peptide of interest has been named 'DRGN1' [1]. The actual full length DRG1 amino acid sequence of DRGN1 if you want to use it: PSKKTKPVKPKKVA

As a genetically encoded peptide it has a few advantages over the traditional small molecule antibiotics you might know about from being prescribed by your doctor:

- It retains anti-biotic effect on gram-negative (hard to attack because they have a secondary wall) bacteria.

- It's mechanism of action is less well understood, but because it's not obviously just a 'signal jammer' than a small molecule antibiotic, developing resistance to anti-microbial peptides seems more difficult than with small molecules.

- It has anti-biofilm properties as well as well as anti-biotic properties (biofilms are a royal pain in hospitals - think catheters...)

- Anti-microbial peptides also often have a strange effect where they activate wound healing in non-microbes (people), rather than just being an ineffectively diluted poison or entirely benign (the way most small molecule antibiotics are).

- My favorite though, because it is genetically encodable, the anti-microbial properties can be conferred to other genetically encoded tools/machines/proteins. If you fuse the amino acid sequence to another protein's sequence, the new fusion protein will likely also have anti-microbial properties.

Spider silk gloves could have this peptide woven into them - and the R&D cost to at least try it out is likely a few hundred bucks and a day or two of effort, CRISPR could deliver a sequence that produces this peptide, or a protein that contained this peptide. The peptide could be produced at commercial scale attached to another 'filler protein' to coat stents/catheters to prevent biofilm buildup - adding exactly zero production cost if such a filler protein is already being used. Or fused to a protein that other 'good' bacteria already produce to prevent biofilm formation where it shouldn't be. Because it can be encodedly produced by nearly all life, it can be introduced genetically as a one-time cost/effort, letting the organism then produce the antibiotic, rather than having to mass-produce the antibiotic in some chemical reaction.

[0] The paper: https://www.nature.com/articles/s41522-017-0017-2

[1] DRG1: https://serotiny.bio/notes/proteins/drgn1/

Does the fact that it's a peptide mean it won't survive digestion and can't be taken orally?

On a silver lining, this may mean that people won't give this thing to cattle and it won't accumulate on the wild. That may delay bacteria resistance.

This is one of the ways it's been sold. But, we've tried D-enantiomer peptides too, which aren't as readily degraded.

Don't farmers ever inject stuff into cattle?

It's more expensive. Farmers avoid injecting things in healthy cattle.

It depends on the peptide and how it's affected by gastric acid. Some peptides can't be used at all, some can be modified so that the bioactive chemical is a result of digestion.

Just to confirm, are you saying that this "miracle cure" news article (which are notoriously bullshit) might actually be true?

It's not a miracle cure, it's just a nicely different way of attacking a problem. It still has tradeoffs - I'm not versed on what they all are, but its tradeoffs are of a different kind than of small molecules. A few guesses of what those tradeoffs might look like: A peptide will be more expensive to synthesize in bulk, it will not have as long of a shelf-life, it likely has a different (not perfect) resistance mechanism and will be more or less effective on different specific microbes. It's likely not as effective on a per/molecule basis. And it's much larger, meaning it will have a greater difficulty diffusing through the body of an organism - and might actually be degraded more quickly once inside an organism because it's peptide-like.

But the mere fact that there are alternative tools in our toolbox for different scenarios is useful in our fight against disease (if not a 'miracle').

DRGN1 is not the first of such antimicrobial peptides, but it was found in a systematic way, and once it was found it was systematically made more effective. This hints at workflows to mine and refine more genetically encoded peptides like it in the future.

Thank you very much for the insight!

The use cases are quite limited since it can only be applied externally (e.g. wound infections) and not against systemic infections.

Even there, there is quite a bit of potential for allergic reactions.

There's always the problem of antibiotic resistance. With the current trend of personal medicine, we might as well switch to bacteriophages [1]. In Georgia and Russia, people have been using the technique for decades.

[1] https://en.wikipedia.org/wiki/Phage_therapy

Phage would be useful but bacteria are likely to be able to resist engineered phage as well.


The abstract states the opposite of the parent. It says that while bacteria develop resistance in the lab to phases that co-evolve, it is unlikely to be a problem in the real world.

>Bacteriophage therapy, the use of viruses that infect bacteria as antimicrobials, has been championed as a promising alternative to conventional antibiotics. Although in the laboratory bacterial resistance against phages arises rapidly, resistance so far has been an only minor problem for the effectiveness of phage therapy. Resistance to antibiotics, however, has become a major issue after decades of extensive use. Should we expect similar problems after long-term use of phages as antimicrobials? Like antibiotics, phages are often noted to be drivers of bacterial evolution. Should we expect phage-treated pathogens to develop a general resistance to phages over time, a resistance against which only, for example, hypothetically co-evolved phages might be infective? Here we argue that the global infection patterns of phages suggest that this is not necessarily a concern as environmental phages often can infect bacteria with which those phages lack any recent co-evolutionary history.

Antibiotics are incredibly cheap to manufacture and easy to use which is a large part of their appeal.

You know, in hindsight, of course Komodo Dragons would have neat antibacterial techniques.

Interesting to learn that the "bite and sepsis" theory was debunked-ish years ago.

Also interesting to learn that they're hard to study? It surprises me that such a well-known species is still that opaque, and the article gives some hints as to why.

Curiously the peptide is derived from a histone protein. Histones are the 'spools' around which genomic DNA is wrapped. Histones are found in the nucleus inside dragon cells. There probably should be no bacteria there even under really bad infection conditions unless the cell itself is being totally destroyed. It's not immediately obvious to me why a histone would have such antibacterial properties. But it's almost certainly not the obvious "bite and sepsis" theory, as you state. I'm not sure it is an 'of course' here - rather it might actually be a lucky find while playing with the truly cool sounding 'dragon's blood'.

edit: Huh - after getting curious it looks like the above is precisely my 'incongruent expectation'. From this article in 2001 about antimicrobial histone peptides found in salmon [1]:

"Most antimicrobial activity is an extracellular event or occurs in the cellular lysosomal compartment. Therefore, an in vivo antimicrobial role for salmon histone H1 might seem incongruent with this protein’s assumed nuclear location and nucleosomal role. In mammals, however, histone H1 has been found outside the nucleus. It is present in the cytosol of human intestinal villus cells, from which it is released into the intestinal lumen during normal cell sloughing. Histone H1 is also found on the surfaces of murine macrophages where it serves as a receptor for thyroglobulin and it is a cell surface protein in murine neurons and in human monocytes. Therefore, histone H1 is not limited to the nucleus in all cells and it may be released to locations where it can act as an extracellular antimicrobial agent. Moreover, an antimicrobial role has been proposed for histone H1."

[1] (2001) http://www.sciencedirect.com/science/article/pii/S0006291X01...

Interesting! Neutrophils can actually release their chromatin to engage bacteria through NETosis, so histone proteins having antibacterial activity does make some sense.


Perhaps keeping the big guns locked away in the nucleus means that they're active when an entire cell has been destroyed? That wouldn't help the destroyed cell, but it might help nearby cells?

> It's not immediately obvious to me why a histone would have such antibacterial properties.

> I'm not sure it is an 'of course' here - rather it might actually be a lucky find while playing with the truly cool sounding 'dragon's blood'.

It's most likely a result of the method used to pick peptides out of the blood samples [0]. Histone peptides have lots of K/Rs, and the bait used to trap the peptides is tuned to pull out small peptides with >5+ (? IIRC) net positive charge. So, pretty sure it's a lucky find while sifting through lots of histone peptides, where something inhibits/degrades biofilm formation and helps wounds close.

[0] http://journals.plos.org/plosone/article?id=10.1371/journal....

(This is the best comment chain and you are all the best posters. :D )

Wild dragons might have even more defenses against infection, but the researchers said they were unlikely to find out.

“I wouldn’t turn down wild dragon blood if it was sent to me and I thought it was collected ethically,” Dr. Bishop said. “But I’m not going to go out in the wild to try to get it.”

Why the different attitude towards mice and guinea pigs?

Komodo dragons have a relatively small population which researchers wouldn't want to disrupt on a large scale.

Not that researchers collect their mice from the wild...

Also, they're a protected species which is fairly large and aggressive - so getting a sample without causing any harm to the animal would involve a certain amount of risk of getting significant chunks of tender flesh torn from one's body.

Why not get a blood sample from a zoo? I'm sure they already take blood samples from time to time. They could just request a portion of the next blood sample. Someone should write to the authtor.

A related coverage of the same story by The Economist. http://www.economist.com/news/science-and-technology/2171780...

Turns out the idea of Komodo dragons having extra bacteria in their mouths is a myth.


As animals go extinct, we lose the opportunity to borrow great ideas from their biology.

That is the annoying thing about all those "Save the planets" pitch of the green and sustainable measure. Short of nuking everything, nature will be fine a few thousands years after humanity is forgotten. That should really be "Save humanity".

Disappearing ecosystem threaten directly humanity: food, water, even climate.

That's just the tip of the iceberg though. A lot of innovation are still coming from nature. We rely on solution already found by millions of years of evolution to solve our problem. Short of AI singularity, there is no substitute.

The fact that it doesn't work in broth and only works in low salt phosphate buffer conditions is a big red flag in my opinion.

Very nice: a justifiable clickbaity headline.

It was either Komodo Dragons or Bearded Dragons. Not clickbaity at all for a reptile lover. :)

I shared a link to the same study on Twitter four days ago with the headline "Researchers create healing elixir from the blood of a dragon." Perhaps I'm not as original as I thought.

Reminds me of the other HN front page article about bleeding crabs. They lost to think you can steal animal blood and get away with the karma.

If that sounds too spiritual to you, consider even Newton's 3rd law, "For every action there is an opposite and equal reaction". Humans are swiftly bringing their own demise in the name technological advancement.

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