2 Strange But True Facts About Spirochetes

Image: Kilauea Volcano
by Brian Snelson

I have a few strange but true facts about spirochetes to share which you may not know. A few are ones I have shared here before  - but most are not something about which I've already written. What you read here today may surprise you...

• Many people call Borrelia burgdorferi spirochetes Gram negative bacteria. However, Borrelia burgdorferi are not Gram-negative bacteria even if a Gram negative stain works on them:
  
  "Borrelia were thought to be Gram negative because of their double membrane structure, but genetic analysis places them - along with other spirochetes - into a separate eubacterial phylum. Ultrastructural molecular and biochemical studies have emphasized the wide taxonomic gap between spirochetes and Gram-negative bacteria."
  
  - From "The Genus Borrelia" by Melissa Caimano. Prokaryotes (2006) 7:235-293.

• Unlike Leptospira and Brachyspira, spirochetes in the Borrelia and Treponema genera appear to have acquired Phenylalanyl-tRNA synthetase (PheRS)  genes from Archaea through horizontal gene transfer. [1] Borrelia and Treponema have Archaea genes.

• What are Archaea? It used to be that cells and organisms were labeled as being either eukaryotic (animal, plants, fungi, and protists) or prokaryotic (bacterial). In recent years, a subset of what seemed to be prokaryotic organisms called archaebacteria were shown to have a distinctly different genetic and molecular background than other bacteria. It was determined that these organisms were not bacteria and should become an entirely new domain, Archaea. Despite their differences, there is some evidence that Archaea may be more closely related to Eukaryotes than Prokaryotes.

• Somewhere along the line, an ancient Spirochaeta relative picked up genes from Archaea's order, Thermococcales. Borrelia and Treponema have close affinities with Thermococcus and Pyrococcus (not depicted on tree).[1]

•  The fascinating thing about this genetic relationship is that these genes come from organisms which are extremely thermophilic organisms. They are extremophiles - which means they can live in extreme environments. Thermophilic extremophiles thrive in hot environments such as volcanic vents and hot springs. That genes from extremophiles would end up in mesophilic organisms which thrive in lower temperatures - such as in mammalian and acarian hosts - seems surprising. The highest temperature Borrelia garinii can still grow in is around 41-42 C. That's not anywhere near the high temperatures in which one finds Archaean Thermococcales (often over 60 C, sometimes as high as 100 C).

• This all does seem really weird. But the reason why it isn't too far fetched to see genes from extremely thermophilic organisms in moderately warm Borrelia and Treponema is more easily understood once you know more about the wide diversity found within the genus Spirochaeta in general. A number of Spirochaeta species live in extreme environments and not just in humans, animals, or ticks. For example:
• S. halophila lives in a high salinity pond on the Sinai shore.[2]
• S. thermophila lives in marine hot springs in New Zealand and Russia.[3]
• S. americana lives in alkaline, hypersaline Mono Lake in California.[4]

Champagne Pool, Wai-O-Tapu, near Rotorua, New Zealand by Christian Mehlführer

• When looking at a phylogenetic tree, Spirochaeta is at the base of the tree and Borrelia and Treponema branch off later. Based on this, the best assessment one can make about the gene transfer from Archaea to Spirochaeta is that the most recent common ancestor of Spirochaeta, Borrelia, and Treponema had to have been very similar to thermophilic Spirochaeta.

• My running joke on this is to imagine a pile of thermophilic Archaea and thermophilic Spirochaeta hanging out around a hot spring together, laughing, joking, and flirting. Before you know it, horizontal gene transfer occurs, and a new form of spirochete is born. (This would make for a good Far Side comic, I just know it.)

• As if having Borrelia acquire Archaea genes wasn't interesting enough, it's been thought that ProS prolyl-tRNA synthetase (BB402) was acquired from a eurkaryote.
  
  
• Treponema spirochetes have a symbiotic relationship with termites. These spirochetes help termites in breaking down cellulose in wood in the termites' guts. So it isn't just ticks which have a symbiotic relationship with spirochetes - termites have one, too.[1, 5]
  
  
• Borrelia burgdorferi survives on the equivalent of tick antifreeze in the tick's midgut inbetween tick blood feeding cycles. Borrelia burgdorferi prefers glucose when in the tick, but it will feast on glycerol instead. See: http://spirochetesunwound.blogspot.com/2011/10/lyme-disease-spirochete-feasts-on-tick.html

• Both Borrelia hermsii and Borrelia burgdorferi metabolize chitobiose and N acetyl-glucosamine, a nutrient of these spirochetes and the major constituent of chitin for the exoskeletons of ticks.[6]

• Borrelia have most of the genes required for the enzymes which make up the mevalonate pathway - a metabolic pathway used by the bacteria for synthesis of isoprenoid precursors. Isoprenoids are very important compounds which are found in over 30,000 products from the three domains of life (Eukaryotes, Prokaryotes, and Archaea). One interesting proposal about how Borrelia has the genes required for these enzymes for this pathway is that they come from the genetic cenancestor - an ancestor which predates the split into the three domains.[7]
   
• In Act II of Samuel Beckett's play, Waiting For Godot, one character, Estragon, curses at the other, Vladimir, by calling him, "Gonococcus! Spirochete!"

Spirochetes continue to hold surprises and mysteries for us all... both good and bad. Another interesting installment of strange spirochete facts could be posted here - probably not too far in the future.

References:

1) Cheryl P Andam and J Peter Gogarten. Biased gene transfer and its implications for the concept of lineage. Biology Direct 2011, 6:47 doi:10.1186/1745-6150-6-47
2) Greenberg EP, Canale-Parola E: Spirochaeta halophila sp. n., a facultative anaerobe from a high-salinity pond. Arch Microbiol 1976, 110:185-19
3) Aksenova H, Rainey F, Janssen P, Zavarzin G, Morgan H: Spirochaeta thermophila sp. nov., an obligately anaerobic, polysaccharolytic, extremely thermophilic bacterium. Int J Syst Bacteriol 1992, 42:175-177
4) Hoover RB, Pikuta EV, Bej AK, Marsic D, Whitman WB, Tang J, Krader P: Spirochaeta americana sp. nov., a new haloalkaliphilic, obligately anaerobic spirochaete isolated from soda Mono Lake in California. Int J Syst Evol Microbiol 2003, 53:815-821.
5) Droge S, Frohlich J, Radek R, Konig H: Spirochaeta coccoides sp. nov., a novel coccoid spirochete from the hindgut of the termite Neotermes castaneus. Appl Environ Microbiol 2006, 72:392-397.
6) Tilly, K., Elias, A.F., Errett, J., Fischer, E., Iyer, R., Schwartz, I., et al. Genetics and regulation of chitobiose utilization in Borrelia burgdorferi. J Bacteriol 183: 5544–5553.
7) Jonathan Lombard and David Moreira. Origins and Early Evolution of the Mevalonate Pathway of Isoprenoid Biosynthesis in the Three Domains of Life. Mol Biol Evol  2011, 28 (1): 87-99. doi: 10.1093/molbev/msq177 http://mbe.oxfordjournals.org/content/28/1/87.full

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0 BBC Article On Assessing Risk (Cellphones, Carcinogens, & Others)

This isn't about Lyme disease and tickborne infections, but it is definitely food for thought when considering the risk involved in any action you decide to take.

Check this article out:

Link: http://www.bbc.co.uk/news/magazine-13886254

Summary Teaser:

BBC News - Go Figure: Do we understand 'risk' of mobile phone use?

What should we make of recent news reports speculating about whether mobile phones cause cancer? It's all about how we deal with uncertainty, says Michael Blastland in his regular Go Figure column.

I highly recommend reading the highly rated comments from the "All Comments" pile, too. Insightful stuff, there.

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3 Mullis' PCR and Borrelia burgdoferi's discovery

Remember I got a pile of books on loan to read? And remember that eccentric Nobel prize winner, Kary Mullis, who was featured in a TED video I posted?

According to Bull's Eye: Unraveling the Medical Mystery of Lyme Disease, Kary's new invention, developed in 1983 - Polymerase Chain Reaction (PCR) - was instrumental in learning more about Borrelia burgdorferi's history:

"One medical researcher who was quick to apply this technique in the medical arena was Dr. David Persing, then at the Yale University Department of Pathology. Being at Yale, Persing was interested in Lyme disease. Among many other projects, he and colleagues used PCR on 102 dried-out or alcohol-preserved tick specimens from the Museum in Comparative Zoology in Cambridge, Massachussetts. The ticks had been collected from various areas in New England between 1945 and 1951; each was tagged with the exact location where they had been collected. The researchers also examined another batch of ticks from the Smithsonian collection in Washington, D.C., some dating back as far as 1924. They found ticks that were positive for the DNA of B. burgdorferi from Montauk Point and from the adjacent Heather Hills State Park from the mid-1940s. 

Several years later, the same group with additional colleagues reported the results of similar experiments done on tiny biopsy specimens taken from the ears of archived mice from the same museum. They found two specimens that tested positive by PCR anaylsis for B. burgdorferi from mice orginally captured near Dennis, Massachusetts (on Cape Cod), in 1894! The DNA from these specimens was identical to the B31 strain that Willy Burgdorfer had found on Shelter Island. 

European investigators have reproduced these experiments using archived ticks from various parts of Europe including England and have found borrelial DNA dating back to the late 1880s as well. If the Lyme spirochete had been around for so long, why did it begin to surface as a recognized medical entity only in the past few decades? This question can be answered in one word --- deer."

I always find history fascinating, especially the connections between technology and information gathering. Here the PCR was invented around shortly after the time that news that Borrelia burgdorferi was the agent of Lyme disease was published in Science in 1982. We know far more about Bb now than we would have if this (or a similar technology) had not been developed at the time it was.

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0 Including the Middle

This was passed on to me in email. The original author's name is Lon Sarver, so credit goes to him and not me. 

Including the Middle

That there is no One True Way does not mean that all ways are equally valid, or that there are no false ways.  Similarly, there may be no one thing that works for everyone, but it does not follow that therefore, everything works for someone.  There are things that don’t work for anyone.

Just because you are a free adult, and do not require my consent to engage in whatever it is that you do (assuming it doesn’t impact me or mine), this does not mean that I have to agree that whatever you’re doing is a good thing.  Even less does it mean I have to approve, or withhold criticism.

I can’t tell you that you don’t like or enjoy something.  I can tell you that, in my experience or understanding, something is actually, objectively harmful.  I can’t tell you that you and other consenting adults cannot do whatever it is you’re consenting to do, but I can object when I see collateral effects impacting me or mine.

You see the distinction, yes?  I’m not arguing tastes, or debating rights in the abstract.  I’m questioning whether or not you’ve thought this through, whether or not you understand the unintended consequences of your actions. 

Consent is not a magic spell to negate ill effect, nor is tolerance or pluralism a barrier that prevents what you do over there from affecting me over here.  Hell, the more interconnected society becomes, the more likely I am to be impacted by people I never meet.  We can argue the extent of this, but not (I think) the fact of it.

So here’s the deal:  I won’t tell you what or who to like, or what’s best for you.  I won’t ask you to tailor your tastes or preferences to defer to mine.  I will tell you if I think you’re factually wrong, or if what you’re doing doesn’t seem to match up with the reasons why you’re doing it.  Feel free to tell me to butt out.  Hopefully, I’ll do it with grace.

If I’m saying that what you’re doing is somehow harmful, trust that I’m not judging you on some measure of Good or Evil, Worthy or Worthless.  Try and take it in the spirit of questioning the effects of your actions, not your intentions.  I’ll probably be a bit more stubborn, here, in proportion to how much I feel that my life is impacted by those effects.  We may not agree on that, but at least let’s agree on what we disagree about.

---

Any thoughts on this? 

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