Wednesday, April 16, 2008

Truth in the Media

Ah, don't we love our local newspaper the Northern Territory News! They do try, but occasionally I'd like to strangle (figuratively of course) the journalist who wrote the story. In this case we sent out a media release talking about the work we did with Sir David Attenborough in November 2006 for his excellent series Life in Cold Blood. After all, it was quite a momentous event for us bringing the great Sir David to the Territory to film our saltwater crocodiles (and I'm sure I'll write more about that experience later).

The original media release contains the following:

"David Attenborough is one of the only people I've met who actually exceeded my expectations" said Dr Britton. "His enthusiasm and fascination for both animals and people was humbling, and there's no better ambassador for how remarkable our crocodiles are than watching David enthuse about them in his inimitable style."

The NT News version was:

"There's no better ambassador for how remarkable our crocodiles are than watching David describe how magnificent they are," Dr Britton said.


They then go on to quote me saying that people come to the NT because it's a place that crocodiles eat people! First of all that was not a quote, and taken out of context of the media release (which is all about the value of crocs to the NT) it rather misses the point!

Oh well, keep trying...

Monday, April 14, 2008

Three cheeky monkeys, one crocodile

Just got back from the Darwin premiere of Black Water, not a film about rogue security agencies in Iraq but rather a crocodile thriller set in the Northern Territory. As you can imagine, the crocodile featured in the film wasn't interested in tea and biscuits with the cast. It is the latest in a series of movies about killer crocodiles, but I reckon this was easily the best. Of course I may be slightly biased because I did a lot of work on the crocodile sequences for the movie!

The film is loosely based on a couple of actual crocodile attacks that occurred in the NT, but they are used as a premise to set up the situation. You might call it a situation horror film: what would you do if you were stuck up a tree surrounded by water containing an unfeasibly hungry crocodile? It's an interesting premise because it plays upon your fears: not knowing where the crocodile is, nor what its motives are, and not really knowing what to do. And although the crocodile behaviour ends up being a little unrealistic by the end of the movie, it was certainly effective. Of course, I'm a sucker for films that take their time to establish atmosphere. I'm not a fan of most modern "horror" films that mistakenly believe that gore is a substitute for generating tension, and in that sense Black Water is quite old-fashioned.

We ended up doing most of the crocodile effect shots for the film, and I was intrigued because the director wanted to use real crocodiles instead of CGI. Perhaps that was a question of budget (Black Water cost $1.2 million Australian dollars) but it turned out for the best - there's no question that the effects look an order of magnitude better and more convincing than any CGI beast, because the crocodile was in control of its movement and not a computer animator. I've long been frustrated by how crocodile effects have been handled in movies, so what better way to show how it should be done than turn to the experts themselves - saltwater crocodiles. Our job was to get footage of the crocodiles doing what was in the script!

Most of this was simpler than you might think if you use the right approach - understand each individual crocodile, know what its strengths are, and encourage it to perform the right behaviour. It's a case of working around the animal, and adapting to what it wants to do. Of course, the director had such a low budget that we had to cut a few corners. One sequence involving a crocodile climbing into a boat could have been done by training the crocodile - something we've done several times in the past - but that takes time. Instead we had to improvise, encouraging the crocodile to run down a bank into the boat rather than climb over the side. And getting it out again? Why, just tip the boat! With a bit of creative editing it ended up looking quite convincing.

In fact, the end result looks so convincing that I've seen reviewers who couldn't tell whether we were using real crocodiles, CGI or models. Of course, the actors were mostly acting against a blue screen so that the crocodiles could be digitally inserted later, but it's real croc behaviour on screen and not an animator's idea of croc behaviour. A lot of these techniques come from years of working on natural history films where you need to understand the animals in order to know how, when and where to film them.

Things didn't always go to plan, though. The director wanted a specific shot of a crocodile launching itself towards camera left, jaws opening. We knew the crocodile that would deliver this shot, so we used a chicken to entice him towards us. The camera was housed in a protective case which was suspended near the chicken. I did warn the camera operator not to get too close to the head or the casing might get bitten. Too late. The crocodile took one look at the chicken, then one look at the white camera housing that was twice the size, and figured it would go for what must have looked like an enormous chicken! Crunch! The croc punctured the housing in several places and dragged it off its mount into the water. Fortunately the camera operator whipped it out of the water by its cable before the crocodile could find the soft, chewy centre. Scratch one very expensive casing, but it did get them a far better shot that ended up in the film.

Black Water has already opening theatrically in the UK, and it's available in the US on DVD, and finally now opening in Australia theatrically. It's definitely worth watching if you want to see real crocodiles on the big screen.

Wednesday, April 09, 2008

Antibiotic factors in crocodile and alligator blood - Part 1

In response to the discovery this week by Dr Mark Merchant (McNeese State University) that American alligators have powerful antibiotics in their blood, I've decided to write a short history of our research into crocodile blood and the discovery of the antibiotic "crocodillin" back in 1998. It's an eventful tale, so in the nature of all good cliffhangers I'm going to split it into at least two parts. Or perhaps that's because I don't have time to write the whole thing at once!

So, let's travel in time back to 1998 (don't worry, we're not staying forever). I was involved in a research project that I thought would have major repercussions around the world, because what we discovered was potentially ground-breaking. I was approached by BBC Science to suggest an interesting research project that they could fund, and film. Did I have an interesting project, oh boy!

I had long been intrigued by the immune system of crocodiles, having seen numerous examples where they generously gave each other some pretty horrific physical injuries - slashes and gashes exposing muscle and bone, ripping off legs, and biting off tails. Just a typical night down the swamp. And yet I couldn't recall ever seeing such wounds become infected. Put yourself in the same position: you've just had your arm bitten, you're lying in filthy water full of bacteria, and you just know it's going to get infected and you might even lose your arm. Not so with crocodiles.

What was it about crocodiles, I wondered, that gave them such potent immune systems? And was it something we could use in human medicine to treat our own disease?

The BBC Science producer, Jill Fullerton-Smith, wasn't particularly interested in this at first. Perhaps it didn't feature enough heads being ripped off wildebeests (the usual staple of TV documentaries about crocodiles)? Or perhaps she needed time to think about it? Yes, that was it. In fact, she apparently woke up one night a couple of weeks later, sat bolt upright in bed, and realised what a great question it was!

So a few months later with a BBC camera crew in tow, we started catching both captive and wild crocodiles to get a few ml of blood. We invited a few "celebrities" along to make the show more exciting (as if a British guy catching crocs in northern Australia wasn't exciting enough!) and sent the blood across to Dr Gill Diamond in New Jersey. I remember suggesting Gill because I'd recently read about his work looking at Komodo Dragon blood, investigating why those lizards with particularly unsavoury saliva didn't infect each other during fighting. He'd developed a technique to fractionate serum into its constituents for amplification and analysis. In short, he seemed like the ideal person for the job of looking at our crocodile blood. After preparing the samples and sending Gill red blood cells, white blood cells (leucocytes) and serum, we crossed our fingers and waited. We actually had to send the samples a second time because the courier company screwed up and let everything defrost and rot. Good job we only sent half the samples in case of such an event!

A few weeks later I was sitting in my office and the phone rang, it was the BBC producer Jill. I could tell she was excited. Gill Diamond had isolated the active constituent in the blood and tested it against a range of bacteria - it killed them all. He then thought he'd try for the jackpot and tested it against MRSA (methycillin-resistant Staphylococcus aureus) otherwise known as Golden Staph - resistant to all known antibiotics.

The constituent in the crocodile blood killed the MRSA bacteria.

I don't think it hit me straight away just how exciting it all was. I think Jill was expecting me to dance around the room punching my fists into the air, but perhaps it was my combined British reserve and scientific scepticism that kept it in check. For a while at least.

The results of our exploits were shown in the BBC documentary "Secret Life of Crocodiles" (also known as "Crocodile Secrets" on the Discovery Channel).

Gill's team and I were able to present these findings at the IUCN-SSC Crocodile Specialist Group meeting in Florida in 2002, and the abstract appeared in the proceedings:

Britton, A.R.C., Diamond, G., Laube, D. and Kaiser, V., 2002. Antimicrobial activity in the blood of the saltwater crocodile (Crocodylus porosus). [abstract presented by G. Diamond at the 16th Working Meeting of the IUCN/SSC Crocodile Specialist Group, Florida, USA, October 2002]

The saltwater crocodile shows a low incidence of infection from serious injuries sustained during intraspecific aggression, in spite of the microbe-laden environment in which it lives. This suggests a well-developed innate immune system, which provides a rapid, non-specific first line of host defense. In other aquatic species such as amphibians and fish, this defense is found in the mucous skin secretions as antimicrobial peptides. Due to the anatomy of the crocodile, we reasoned that a homologous defense would be found in the circulatory system, either as soluble factors or as agents expressed in phagocytic cells. To address the first hypothesis, we extracted serum from wild saltwater crocodiles to isolate naturally occurring antibiotics. The serum was maintained at -80C until fractionation. Serum was fractionated by Reverse-phase HPLC on a C-18 column with a 0-60% acetonitrile gradient, and fractions were assayed for antibiotic activity against E. coli in a modified radial diffusion assay. Preliminary results indicated strong antibiotic activity in several fractions. We have taken a single fraction, eluting at 13% acetonitrile, for further characterization. Based on our initial observations, we predict that the crocodile exhibits both peptide and non-peptide based antimicrobial activity in its blood.

In our next exciting episode, we travel forward in time to 2002 to meet Supercroc!