The first venomous crustacean is found

October 24, 2013 • 5:37 am

The phylum Arthropoda contains four major living groups, usually considered subphyla: Hexapoda (insects and a few other groups like springtails), Myriapoda (mostly centipedes and millipedes), Chelicerata (spiders, scorpions, horseshoe crabs, mites, etc.) and Crustacea (crabs, lobsters, barnacles, shrimp, etc.). Trilobites, which are extinct, are classed as another subphylum.

The first three of these living groups all contain species that have venom, which, biologically, are toxins injected into a prey with a bite or sting (delivery via those methods distinguishes venoms from, say “poisons,” as found in some frogs that are toxic to predators). Up to now, though, no crustaceans had been known to have venom.

This has changed with the publication of a new paper in Molecular Biology and Evolution (advance online manuscript; free), by Björn von Reumont et al. The authors show—not definitively, but suggestively—that some remipedes—rare, blind crustaceans that live in marine underwater caves—have venom that they inject into their prey.

Remipedes were discovered only in 1981, and there are only 17 known species. They constitute a class in the subphylum Crustacea. Here is an individual from the University of California’s Museum of Paleontology. Remipedes are about 10-40 mm long: about half an inch to 1.5 inches:

speleon_b

Previous work had suggested that these species could be venomous, as they have biting mouthparts, but this wasn’t investigated. In fact, the going wisdom was that they fed on suspended particles.  But morphological analysis of one species from the Yucatan in Mexico showed a “highly adapted venom delivery apparatus” as well as mouthparts that could deliver venom, and lab studies showed that captive individuals of the species, Speleonectes tulumensis, could indeed capture and kill small prey.  Here are the venom glands and the paper’s caption:

Picture 2
Figure 1 – 3D reconstructions of Speleonectes tulumensis (Crustacea: Remipedia)
from high resolution SR-!CT data.
A) Ventral and B) lateral view showing the course of the venom delivery system
(VDS), (purple) and its position inside the body. C) Anterior and D) posterior view
focused on the maxillule and the muscle equipment related to the VDS.
Abbreviations: 4 seg, 4th segment; 5-7 seg, 5-7th segment; ab, abductors; ad,
adductors; am, anterior apodemal muscle; br, brain; cep, cephalon; dc, ductus; gl,
gland; mxu, maxillule; phx, pharynx; rv, reservoir; t, tentorium; vm, ventral apodemal
muscle; vnc, ventral nerve cord. Images not to scale to each other, mouthparts and
other structures are not shown.

How did they find the venom? They used “transcriptomics,” a newish way of finding the DNA (and protein) sequences of genes that are actually expressed in organisms, that is, whose DNA is converted into RNA. (Remember that a lot of DNA is “junk” that never does anything.)

The authors extracted RNA from the venom glands, sequenced those RNAs by converting them to DNAs and sequencing the latter, and then translated those DNA sequences into protein sequences (the messenger RNA’s are read into proteins). They then looked in databases for proteins corresponding to known classes of venoms.

And they found at least three types of putative venoms, with 108 different forms of those venoms. The three classes are peptidases, enzymes that dissolve protein, chitinases, which do the same for that material, found in exoskeletons, and neurotoxins.  While the authors didn’t actually isolate the venom itself, they did this indirectly by finding sequences that correspond to things known to be venoms.  It remains to be demonstrated that there actually are venoms in these species that kill prey, but the evidence is pretty strong. And the venom proteins seem most closely related to proteins found in spiders.

Here’s the species that was studied:

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While the results need confirmation (are those venoms actually used to kill?), the authors suggest that “remipedes can feed in an arachnoid manner, sucking the prey’s liquefying tissue out of its cuticle.”

So there’s your fact for the day, and be sure to drop it at the next cocktail party. “Say, did you know they found the first venomous crustacean?” is sure to bring gasps of wonder and admiration over a round of martinis.

h/t: James

______________

Björn M. von Reumont, Alexander Blanke, Sandy Richter, Fernando Alvarez, Christoph Bleidorn, and Ronald A. Jenner 2013. The first venomous crustacean revealed by transcriptomics and functional morphology: remipede venom glands express a unique toxin cocktail dominated by enzymes and a neurotoxin. Mol. Biol. Evol.: mst199v1-mst199.

Thursday: Hili Dialogue

October 24, 2013 • 3:26 am

Hili seems to be getting more philosophical as she ages:

Hili: As I, too, eliminate entities which are beyond necessity, what is the difference between me and Occam’s razor?

A: Ockham suggested more economical thinking and you are more ruthless in action.

Hili: Oh well, I’m a cat.
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In Polish:
Hili: Jeśli ja też eliminuję zbędne byty to jaka jest różnica między mną z brzytwą Ockhama?
Ja: Ockham sugerował bardziej ekonomiczne myślenie, a ty jesteś bezwzględna w działaniu.
Hili: No tak, ale ja jestem kotem.

Readers’ cats: Purruru

October 23, 2013 • 2:46 pm

After the mortality must come a felid. Reader Steve Obrebski sent a picture of his cat Purruru:

Purruru is allegedly a Flame Point Siamese, a breed having  bright, reddish-gold points and brilliant blue eyes, creamy-white, short coats, and look like Siamese cats.  Elsewhere these cats are also called Red Point Siamese or Color Point Shorthairs.  We got him from a Japanese friend who had to move back to Japan.  He is very snuggly with me and my wife, but also likes the laps of visiting ladies. and likes to dash outside (we keep most of our cats indoors) so we have to use a can of special aromatic cat food to entice him indoors.  We have had him for 12 years and he is doing fine.  He was probably 3 when we got him.  We never checked but maybe Purruru is a Japanese word pertaining to cats.

OLYMPUS DIGITAL CAMERA

Steve that they have 6 totally indoor cats, one who lives indoors in winter, and one feral outdoor cat that has adopted them. He also reports that two decades ago they had 23 cats, which is probably a record for readers here.

Again? Phil Zuckerman wins debate with Christian, church refuses to post video

October 23, 2013 • 12:32 pm

Sound familiar? Phil Zuckerman, a professor of sociology at Pitzer College in Claremont, CA, who studies the geography and sociology of atheism (he wrote Faith No More: Why People Reject Religion, Atheism and Secularity, and Society Without God), is asked to debate Christian author David Marshall at Adventure Christian Church in Sacramento.

The topic: “What provides a better foundation for civil society, Christianity or Secular Humanism?” Zuckerman, of course, took the secularist stand.

The preparation was arduous: months of work for everyone. And, as Zuckerman reports at PuffHo, everything was in order. They had agreed to film the debate and post it on Vimeo, and even provided the speakers with nice noms.

But then the unexpected happened: Zuckerman won.

You can imagine what happened next. As he reports:

And so we had the debate. And I won. Now, that’s not my opinion — its the opinion of Adventure Christian church, because they now refuse to post the video on-line.

Instead, what they’ve done is post a series of rebuttals to the debate — refutations and criticisms. But they won’t post the actual debate. And they’ve disabled my ability to even comment on their posted refutations.

When I called pastor Bryan, and asked him why they are refusing to post the video — even after repeated promises of doing so — he replied, “It just didn’t go the way we wanted it to go. We were not represented well.”

Shades of John Haught! Except his excuse was that he didn’t want to subject the viewers to the odious spectacle of me saying bad things about Catholicism.  And, like me in the Kentucky affair, Zuckerman was blindsided:

I was actually quite stunned by Adventure Church’s not keeping their word and being so cowardly. And I shared my dismay with my friends, family and students. But then, yesterday, one of my students came up to me and said, “I’m stunned that you’re so stunned.”

“What do you mean?” I replied. “They were such nice people. And they repeatedly assured me that the debate would be put up on vimeo. Now they won’t do it.”

“Clearly you don’t know a lot of Evangelicals,” she replied. “Sure, they’re very nice. But if you say anything that goes against their party line, you’re out. They can’t handle debate, they can’t handle real dialogue. It doesn’t surprise me at all that they won’t show the video.”

This is why this form of Christianity is inimical to democracy. I can’t imagine Zuckerman, myself, or any other debating atheist refusing to allow the debate to be aired—no matter how bad our performance was.

Imagine what these Christians would do if they turned America into the theocracy they want!

They are indeed afraid to air the underling truth of my position: that no civil society can thrive if it does not exist upon a bedrock of democracy, and democracy is not a Christian value — it is not articulated anywhere in the Gospels, nor is it promulgated, in any way, by Jesus or Paul. Rather, democracy is a secular humanist ideal — something dreamed up and established by and for people.

Over at his website, Christ the Tao, Marshall gives his own interpretation. While admitting that the church agreed to post the debate, he disputes Zuckerman’s interpretation, and even claims that he (Marshall) had the better argument. Note as well that he uses the Haught Evasion: maybe the video was deep-sixed because Zuckerman was too nasty to faith!

[Zuckerman; And so we had the debate. And I won. Now, that’s not my opinion — its the opinion of Adventure Christian church, because they now refuse to post the video on-line.]

[Marshall]: First, I’m not sure that’s the correct explanation for their peculiar actions.  It may be that they didn’t feel I supported their theological views as well as they expected.  It may also be that while both sides offered some good arguments — as both sides did, though I think I had the better ones — the pastors felt that something Phil said might somehow undercut the faith of some listening.  Which seems kind of lame to me, especially since the next morning I preached on boldly and fearlessly engaging with the world.  (“Step out of the boat!”)

But even if the senior pastor thought Phil had the better of the argument, of course it would not make it so.  There are people who always see their own side as winning, and even vote for, say, Alex Rosenberg over William Lane Craig, or think Romney did well in his second debate.  But there are also people in whose eyes opposing arguments loom large, and there are lots of other people who just aren’t qualified to judge.

Honestly, I don’t think anyone who believed Phil wiped up the floor with me in terms of arguments, understood what was going on.  Phil didn’t even attempt to answer most of my main arguments.  And they weren’t exercises in trivia.

Let’s hope the unadventurous Adventure Church finally gets some guts and posts the debate. For right now they’re looking pretty stupid—and pusillanimous.

One last round with Eric

October 23, 2013 • 10:19 am

I won’t prolong my dispute with Eric MacDonald about whether we have free will, whether our behavior is truly deterministic, or whether there are “ways of knowing” other than empirical observation and reason (science construed broadly). I’ll just post and comment briefly on two statements that he made in his response to my critique of his views on Monday. These appear in yesterday’s piece on his site Choice in Dying, a piece called “Lurching sideways.”

#1. Responding to a famous characterization of “scientism” in the Oxford Dictionary of Philosophy, Eric says this:

“Nobody espouses scientism it is just detected in the writings of others.”

This, I am sad to say, is not true, as a number of recent remarks by Steven Pinker, Jerry Coyne and Richard Dawkins have suggested, and all the discussion around this issue has not convinced me that Kitcher, Haack, Hughes, etc. are wrong in their belief that scientism is a growing problem. I happen to think that any doctrinaire belief system is a problem – even one that gives the palm of victory to science. Science is a marvellous human achievement. It also constitutes a problem, and may, indeed — the signs are ominous — spell the end of human life as we know it on this rapidly overcrowding, polluted planet. How long does it take to “kill” an ocean? Does anyone know? And what would be the effect of that on life on this planet? Yet it seems that we are well on the way to acidifying the ocean so ruinously as to make it uninhabitable by the creatures that make their home there, without knowing how quickly this essential ecosystem could collapse. You may say that these consequences are the result of the misuses of science, or the continued hegemony of religion, but that is not at all clear. However, I think the dehumanising possibilities of doctrinaire scientific atheism are just as real as the dehumanising possibilities of religious tyranny. Indeed, the sheer power of science makes the dangerous effects of scientific dogmatism even more likely.

So science is responsible for polluting the oceans? And enablers of science, like Pinker, Dawkins, and I, are implicated in this?  Really, isn’t this the result of human greed (dumping crap into the oceans and overfishing)? How can we make science responsible for that? We might as well, as Steve Pinker said, indict architecture as responsible for the Nazi gas chambers. The problems here are technology in the hands of immoral or greedy people.  Do we blame toolmakers because people have used shovels, chisels, and hammers to murder people, or chemists for gas attacks in World War I?

And as for the “danger of doctrinaire scientific atheism” and its supposed similarity to religious tyranny, all I can say is that no “scientific atheist” has ever threatened to kill somebody, bombed marathons, shot girls for going to schools, or flown planes into buildings. (Note, too, Eric’s subtle transformation of “doctrinaire scientific atheism” into “scientific dogmatism.” Where did the “atheism” go?) Are climate-change denialists “scientific dogmatists,” too? What about creationists?

Both of Eric’s claims above are so ludicrously wrong, and yet so similar to those made by theologians (“science does stuff as bad as religion does”, and “science is just as fundamentalist as the worst forms of Christianity”), that I am wondering if Eric really is undergoing a confluence with theology. He may still reject God, but he adopts the same arguments theologians use against science to protect their god.

#2: About determinism:

There is far more evidence, if you take philosophical reasoning to be a rational kind of critical enquiry that provides evidence in the form of reasons, for “compatibilist” free will, than there is for outright determinism, if it even makes sense to “speak” in terms of determinism. I assume, therefore, that determinism is merely a doctrinaire or dogmatic claim, and should be, for that reason, rejected, until there is some evidence one way or the other for affirming one or the other stance as true.

Really, we should reject determinism until more evidence is in?  Has Eric ever flown in a plane, dropped a rock, played pool, or cut himself? The consequences of such actions are pretty much predictable, and much of our technology—technology Eric must use—depends on physical processes whose results are absolutely predictable.

The statement that there is far more evidence for “compatibilist” free will—a concept that varies among philosophers and cannot necessarily be confirmed empirically—than for physical determinism is simply silly.  In fact, it’s not even wrong.