CROCLIST: Crocodilian immune system studies

[Adam Britton]

Chris,

Most of the work hasn't been published yet pending one key study that's
still ongoing (long story), but the following bits and pieces have been:

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

ABSTRACT: 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.

Merchant, M. and Britton, A.R.C., 2006. Characterization of serum complement
activity of saltwater (Crocodylus porosus) and freshwater (Crocodylus
johnstoni) crocodiles. Comp. Biochem. Physiol. A Mol. Integr. Physiol. A.
143(4): 488-493  (sorry, I don't have a PDF of this - Mark made all the
final changes)

I'm continuing to work with Dr Merchant who is driving this research now,
and he's also published quite a few papers from his lab's work on the
alligator immune system.

Merchant ME, Roche C, Elsey RM, et al. Antibacterial properties of serum
from the American alligator (Alligator mississippiensis) COMPARATIVE
BIOCHEMISTRY AND PHYSIOLOGY B-BIOCHEMISTRY & MOLECULAR BIOLOGY 136 (3):
505-513 NOV 2003

Merchant M, Thibodeaux D, Loubser K, et al. Amoebacidal effects of serum
from the American alligator (alligator mississippiensis) JOURNAL OF
PARASITOLOGY 90 (6): 1480-1483 DEC 2004

Merchant ME, Pallansch M, Paulman RL, et al. Antiviral activity of serum
from the American alligator (Alligator mississippiensis) ANTIVIRAL RESEARCH
66 (1): 35-38 APR 2005

Merchant ME, Verret B, Elsey RM Role of divalent metal ions in serum
complement activity of the American alligator (Alligator mississippiensis)
COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY B-BIOCHEMISTRY & MOLECULAR BIOLOGY
141 (3): 289-293 JUL 2005

Merchant ME, Roche CM, Thibodeaux D, et al. Identification of alternative
pathway serum complement activity in the blood of the American alligator
(Alligator mississippiensis) COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY
B-BIOCHEMISTRY & MOLECULAR BIOLOGY 141 (3): 281-288 JUL 2005

Adam



-----Original Message-----
From: croclist-bounces at lists.gatorhole.com
[mailto:croclist-bounces at lists.gatorhole.com] On Behalf Of Christopher Law
Sent: Monday, 16 October 2006 3:02 AM
To: croclist at lists.gatorhole.com
Subject: CROCLIST: Crocodilian immune system studies

Hello everyone,

    I am trying to find studies on the crocodilian immune system,  
more specifically the studies conducted by Adam Britton.  I can only  
seem to find news articles, but I can't appear to find the actually  
research articles anywhere.  Can someone please point me in the right  
direction?  Or, if someone happens to have copies of the research  
articles and wouldnt mind going through the troubles of emailing them  
to me, that would be great as well.

Best Wishes,

Chris Law
www.herpfanatic.com
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