Its not a tumour. Oh wait, it IS a tumour!

I admit it, I LOVE the movie Total Recall.  I love its cheesy special effects, I love The Governator pulling a bug out of his brain through his nose, and I love Sharon Stone in all her over-permed 80’s pant suit glory.  But most of all I love Kuato, the mysterious little conjoined-twin character who leads the Martian rebels in their fight against the Richter character (played by the terrifically melodramatic Michael Ironside) and his cronies.

Thing is, there are weirder things in the world than Kuato, and one of the all-time weirdest is a type of cancerous tumour called a teratoma.  Teratoma’s take the cake in my book for the strangest and most fascinating of all pathologies, and fish get really good ones, as you’ll see.

Typically, tumours arise when a cell in the body is transformed by a mutation that interferes with the normal cycle of cell growth and death that’s essential for regulating tissues.  Instead, the cell multiplies in an uncontrolled or inappropriate fashion.  These mutations are sometimes built into our genes, and sometimes caused by viruses, by contaminants in the environment, by radiation, or even by spontaneous mutations from mistakes in DNA replication.  Anyway, the type of tumour that develops depends on the tissue of origin, and there’s a whole taxonomy of names that describe them accordingly.  For example, a malignancy in the liver is a hepatocellular carcinoma, while a cancer of the pigment cells in the skin is a melanoma. 

But what happens when you get a tumour of a pluripotent or stem cell?  That is, a cell that hasn’t yet decided what to be when it grows up.  The answer is a teratoma.  What makes teratomas so cool and gross and awesome and weird is that as the cells in the tumour multiply, they can and do turn into other different cell types as they go, which is a perversion of the normal differentiation that stem cells would go through when they are maturing into a liver cell, a skin cell or whatever.  The result is a tumour that, at the tissue level, may resemble or contain one or more other tissues!  My colleague and pathologist extraordinaire Jeff Wolf introduced me to teratomas when I took the AQUAVET course at Woods Hole and I was horrified and fascinated.  I saw Jeff last week at the ISAAH meeting in Tampa and asked him if I could share one of his fish teratoma cases with you.  So here it is:

What you’re looking at is a very thin slice of the gonads of a medaka (a type of small fish thats used a lot as a model in biomedical research) stained with haematoxylin (blue) and eosin (pink), to reveal the structure of the tissue.  Ovaries and testes have a pretty high population of stem cells, so teratomas tend to be more common in gonads, but they can turn up anywhere that stem cells occur in the body.  Lets take a closer look, for those who may be unfamiliar with histopathology:

I outlined the tumour in yellow.  Most of the tissue surrounding it is gonad, and you can even see a few big blue oocytes scattered here and there, but you may also see how the tumour is sort of squishing the surrounding tissue.  But what’s cool is all that stuff inside.  The concentric structure marked 1, thats a bit of an eye - you can see the pigment layer of the retina and the alternating layers of rod and cone cells.  All that stuff marked 2 that goes from 12-4 on the clock face, thats all brain tissue.  The stuff marked 3, thats cartilage, and at 4, fish scales (the thin pink lines) and skin, complete with rows of mucus cells along the outside!  There’s just 4 or 5 tissue types in this lesion, but it could just as easily form a bit of gut, some pancreas or a bit of kidney, anything really.

How does this happen?  How can seemingly intact retina grow inside a tumour, a lesion whose very nature implies uncontrolled growth?  The answer seems to lie in cell-cell signalling.  As the first teratoma cell differentiated into a retinal cell, it sent out signals to surrounding cells to say “right lads, we’re forming an eye” and those cells fell into line as the lesion developed.  This is a normal process thats essential for proper development of embryos, but in a perverted recapitulation, we instead get bits of intact tissue forming in tracts within a tumour.  If you think its weird in a fish, wait till you see the ones in mammals: they can have bones, teeth, even fur, growing embedded within the tumour.

Teratomas: fantastically interesting and creepy, no?

It seemed like a good idea at the time...

Human-powered plankton tow, in an attempt to catch larval fish under sargassum without catching the sargassum itself. 

Note to self: towing 15 feet of 100 micron mesh through the water is HARD WORK

Amazing satellite video of Hurricane Igor

Hurricane Igor is a big beast allright.  If you don’t believe me, check out this spectacular QuickTime movie from the Space Science and Engineering team at the University of Wisconsin, and after you pick your jaw up off the floor, go over to their blog and check out the rest of their great data.  Just look at that eye; I love the way the shadow casts across it as the sun goes down.  You can also see convection cells to the left and the lower right of the storm, where air is moving rapidly upwards. (if the video stops, double click it to restart).  Thats just made of awesome.

Why is this on a marine science blog?  Well, its over the ocean, so that counts, right?  Seriously, hurricanes are really marine phenomena.  They’re driven by the tremendous amount of heat that builds up in the tropical oceans during the summer months.  That heat warms and moistens the overlying atmosphere, as the energy stored in the ocean fluxes back into the air.  Warmer air is less dense and so you end up with a focused area of low pressure, and the moist air rising up to colder higher parts of the atmosphere, causing rain.  Add in some favourable winds and and dash of the coriolis effect and the whole thing starts to spin, forming into a tropical cyclone.

Via my colleague Brian Colle at Stony Brook U.

Visualising the New Zealand earthquake

New Zealand is very active for eathquakes and vulcanism, unlike its bigger brother Australia, which is perhaps the most tectonically stable piece of crust floating around anywhere on this ball of magma. Thats because NZ sits atop the place where the Pacific ocean floor dives down under the aforementioned Australian plate. On September 4th there was a big slip around Christchurch, resulting in an eathquake measured at 7.4 in magnitude, which damaged hundreds of buildings and was felt all over New Zealand. Chris McDowall is a kiwi informatician who assembled 6 months of NZ earthquake activity into a cool data visualisation that shows just how common it is for the ground to move down there. Each earthquake appears as a purple blob, of intensity matched to the magnitude of the temblor, leaving a little red mark behind to show the accumulation over time. I was struck by how much of the activity is concentrated in two parallel lines running southwest-northeast on the north island. When the Christchurch quake hits the middle of the south island it just seems so big and out of place. Anyway, its a great bit of data visualisation and I thought you might like it too. Via my colleague Malcolm Bowman at Stony Brook U.

Visualising six months of New Zealand earthquake data (Apr 1 - Sep 7, 2010) from Chris McDowall on Vimeo.

How cute is this little guy?

This is one of the smaller whale sharks I’ve seen on YouTube. Starts around 8:25 into the video (I can’t seem to work out how to embed a video half way through). You can see him do a bit of subsurface ram filtering, and he coughs a couple of times, which is a behaviour we see at the aquarium from time to time. 

Those remoras are a real drag…

The power of a rolling sea

A colleague from my old university sent around this video as a reminder of why you need to secure things while working on the university research vessel.  Its the Pacific Sun cruise liner, which hit a storm in 2008.  It starts out mildly amusing, but ends up downright scary.

Check out the tool cabinet missile around 40 seconds into this one yikes…

Oceans on the Edge

Back in Spring 2009 I attended a creative and unusual meeting at the Aquarium of the Pacific in Long Beach CA, which their director Jerry Schubel had organised to discuss pressing issues facing the worlds oceans.  It was a fantastic mix of scientists, film-makers, journalists, bloggers, game designers and social scientists, and it really opened my eyes to the sucky job we scientists sometimes do in explaining the importance of our work.  Everytime one of the scientists lapsed into jargon or science-ese, one of the others would jump up and say “ya lost me” and drag us back to reality.  It was very enlightening, to the point where it actually inspired me in part to start this blog.

One of the final products of that meeting is now in print.  The four key areas we identified and discussed were summarised in reports that are intended to be part of educational packages that grew out of the workshop.  I co-authored the one about oceans and their connection to human health.  You can get it, and the other three on Coastal Hazards, Fisheries, and Pollution, here.

Twittering from ISAAH6

I am live twittering from the International Symposium on Aquatic Animal Health in Tampa. If you're interested, follow me @para_sight or follow #ISAAH6

Host, pathogen, and ... ammonia?

In  either a happy accident or a particularly clever piece of scheduling, there were two talks back to back in todays ISAAH program that dealt with the role of ammonia (NH3) in fish diseases.  But these two talks gave surprisingly different perspectives on the role of this nitrogen waste compound in the mechanism of disease.

In the first, Ron Thune from LSU talked about a bacterial disease of catfish cased by Edwardsiella ictaluri.  Edwardsiella is an obligate intracellular parasite of macrophages, which is to say that the bacterium must live inside a host cell, in this case a the major scavenging cell in the immune system.  How does that work, that a parasites can (indeed NEEDS to) live inside the very cell that the host would use to attack it?  In a normal macrophage, an offending bacterium would be engulfed in a small bubble in the cell called a vacuole, and the macrophage would drop the pH inside that vacuole, to kill the bacterium.  Edwadsiella cannot survive at those sorts of low and corrosive pH’s, but it cleverly produces ammonia, which forms a sort of pH buffering system that raises the pH to a level where E. ictaluri not only survives but thrives.  What makes this unusual is that ammonia is normally a waste product that is in itself toxic to many biochemical systems.  The idea that a pathogen uses this waste chemical to improve its own conditions is fascinating.

In the second, even more surprising talk, Drew Mitchell looked at a different bacterial disease called columnaris.  Some other researchers had noticed that fish survival in the face of columnaris outbreaks was better in cruddy water quality, which is totally counter-intuitive.  So Drew and his co-authors did a controlled study of the progression and resolution of columnaris disease at different concentrations of ammonia in their water; ammonia being the greatest component of excreted fish waste.  Sure enough, at concentrations of the toxic unionised form of ammonia that most folks would avoid for fear of killing their fish (0.4ppm and higher), the columnaris agent was effectively eliminated and fish survival actually increased!  The idea that a toxic metabolic waste product could serve to protect a fish from a pathogenic bacterium was, to me, completely counter-intuitive and surprising!  We would normally think of ammonia as an environmental stressor that might make a fish MORE susceptible to disease, not less.  What Drew discovered was more like the protection against the malaria parasite conferred on people by the genetic disease sickle cell anaemia.

Lets recap for a second.  The first study showed that a bacterium can use ammonia to create conditions conducive to survival within host cells, making a disease worse.  The second showed that ammonia can (somehow, as yet unspecificed) protect fish from a different bacterial pathogen, making the disease better.  I guess it goes to show that any single chemical player can have a range of roles in the complex biological landscape of disease, and that we have to be careful about thinking that any given chemical is “good” or “bad”.  Best of all, both studies involve a big element of surprise, and that always makes biology fun and exciting.

ISAAH 6 underway!

Today was registration day for the International Symposium on Aquatic Animal Health at the (very grand) Marriott Waterside in Tampa.  Usually thats a mellow check-in day but it was also ExCom meeting time for the Fish Health Section and then a Session Chair co-ordination meeting.  I was delighted to see again a colleague from Kamchatka, Tatiana Gavruseva, who I first met at a US/Russian bilateral exchange meeting last year in the DC area.  Kamchatka-Moscow-Washington-Tampa - what a flight, can you imagine? I am aurprised she can keep her eyes open.

Ice-breaker calls….

Play Bit-o-Critter round 30 - and win stuff.

In celebration of the thirtieth round of Bit-o-Critter: prizes!  The winner this time will receive a bottle of SPF 30+ ReefSafe sunscreen -  its great stuff; I used it in Mexico this summer - and in case you forget to apply, a bottle of Beach Buff burn cooler.  Both are from the kind folks at Tropical Seas. 

Here’s the critter.  First correct full scientific name in the comments wins.  And don’t panic if you don’t see your comment straight away - the order of submission is preserved in the moderation queue.

 Good luck

Do you know about this course?

My colleagues at the University of Florida are running an online Aquatic Animal Conservation course, with credit offered at both the undergraduate and graduate levels.  If you’re into marine conservation or you have a particular interest in Florida’s aquatic ecosystems, you might really dig it.

Check out the flyer here.

Tampa - brace yourselves...

Next week I will be in sunny Tampa for the 6th International Symposium on Aquatic Animal Health, a great meeting that happens every four years covering the gamut of AAH from aquaculture to fisheries to aquariums and even marine mammals (they’re OK too, ‘spose).  The energetic Andy Kane from UF and the lovely and talented Sarah Poynton from Johns Hopkins are chairing the program and it looks to be a great set of folks attending. They’ve got me co-chairing a session about parasites in molluscs, which should be fun, and my own talk will be about metabolomics in whale sharks, a collaboration with colleagues at Georgia Tech.  What’s metabolomics, I hear you say?  Well, perhaps I’ll post about it while I’m there (you know, AFTER I make the powerpoint.  I should probably start that…).

The AGM for the Fish Health Section of the American Fisheries Society will also be there, so we’ll be mixing hundreds of science talks with some serious chit-chat about the state of fish health science in this country, which has evolved significantly of late, in part because of new disease epizootics (VHSV anyone?), the National Aquatic Animal Health Plan and the increasing role of veterinarians in fish health research (the more the merrier, I say).

Should be a great meeting.  Anyone got any “must hit” spots while I am there? or want to meet up for a cuban sandwich, or better yet, a couple of cervezas?

Wanted: Lionfish, dead or alive

Loved this banner, which was hanging in the lobby at the hotel in Mexico where we were based last week and where, coincidentally, there was a lionfish eradication strategy meeting going on.  I think Se Busca literally means “you see” but in this case I think it means “Wanted”, as in an old-time wanted poster. Perhaps a Spanish speaking reader can clarify for us.  Pez Leon is definitely Lionfish.

He’s terrifically grouchy-looking.  Love it.