download the PDF here - Amphibian Specialist Group

sensitivity does it. This assumption could
be analyzed through the probit regressions
parameters. The steeper slope (b) in
double exposure (DE) treatment really
gives information about the increment
in the range of sensitivity. The previous
ammonium nitrate pulse induces the
reduction in the LC50 values (DLC50),
indicating a certain increment in the E.
calamita larvae sensitivity. Although this
information was obtained under laboratory
conditions, could help us to understand
what might be happening under these
circumstances in aquatic ecosystems.
Full article: García-Muñoz, E.
et al. (2011) Effects of previous
sublethal pulse to ammonium
nitrate on mortality and total
length on Epidalea calamita larvae.
Chemosphere 84 671–675
Amphibian immune defenses
against chytridiomycosis: Impacts
of changing Environments
By Louise A. Rollins-Smith 1 , Jeremy P.
Ramsey 2 , James D. Pask 3 , Laura K. Reinert 3 and
Douglas C. Woodhams 4
Amphibians are currently suffering
devastating declines and extinctions
in nearly all parts of the world due
to the emerging infectious disease
chytridiomycosis caused by the chytrid
fungus, Batrachochytrium dendrobatidis.
The publication linked to this abstract
briefly reviews our current understanding
of amphibian immune defenses against
B. dendrobatidis. We review what is
known about the impacts of temperature,
environmental chemicals, and stress
on the host-pathogen interactions and
suggest future directions for research.
Infectious zoospores or bacteria landing in
the skin mucus must overcome chemical
defenses, including antimicrobial peptides,
lysozyme, secreted antibodies, and bacterial
metabolites that may have antifungal or
antibacterial activities. If B. dendrobatidis
zoospores reach the growing epidermal
cells, they would be expected to alter
the properties of those cells and attract
the attention of antigen-presenting cells
such as dendritic cells or macrophages.
These cells would be expected to recruit
an adaptive cell-mediated and antibodymediated
lymphocyte response. However,
factors produced by the fungus can
interfere with lymphocyte responses by
induction of apoptosis of lymphocytes. The
immune defense against chytridiomycosis
is impacted by a variety of factors that
may affect the overall survival of the host.
Because tadpoles carry mild infections in
their mouthparts, changes in the immune
system at metamorphosis may result in
greater susceptibility to the development
of disease at that time. Stress due to
a number of environmental factors
including poor nutrition in marginal
habitats and enhanced activity during
breeding may elevate corticosteroids. If
infection by B. dendrobatidis impairs
ion transport in the skin, the endocrine
response that balances cutaneous ion
transport may also elevate glucocorticoid
or mineralocorticoid responses resulting
in immune suppression. The immune
system of amphibians is highly temperature
sensitive, and even small reductions
in temperature may impair immunity.
Environmental chemicals may also impair
innate and adaptive immune responses.
Author details: 1 Departments of Pathology,
Microbiology and Immunology and of
Pediatrics, Vanderbilt University Medical
Center, Nashville, TN 37232; Department
of Biological Sciences, Vanderbilt
University, Nashville, TN 37235; Center
for Species Survival, Conservation
and Science, National Zoological Park,
Smithsonian Institution, Washington,
DC 20013-7012. 2 Department of Biology,
James Madison University, Harrisonburg,
VA 22807. 3
Department of Pathology,
Microbiology and Immunology, Vanderbilt
University Medical Center, Nashville,
TN 37232. 4
Institute of Evolutionary
Biology and Environmental Studies,
University of Zurich, Winterthurerstrasse
190, CH-8057 Zurich, Switzerland.
Full article: Rollins-Smith, L.A.,
Ramsey, J.P., Pask, J.D., Reinert,
L.K., and Woodhams, D.C. 2011.
Amphibian immune defenses
against chytridiomycosis: Impacts
of changing environments. Integr.
Comp. Biol. Aug. 3, 2011.
July
Alton, L. A. et al. (2011) A small increase
in UV-B increases the susceptibility of
tadpoles to predation. Proc. R. Soc.
B: 278; 2575-2583. (l.alton@uq.edu.au)
Aronzon, C. M. et al. (2011)
Stage-dependent toxicity of 2,4-
dichlorophenoxyacetic on the embryonic
development of a South American toad,
Rhinella arenarum. Environmental
Toxicology: 26; 373-381.
(herkovit@retina.ar)
AmphibiaWeb Recent Publication List
This reference list is compiled by Professor Tim Halliday (formerly DAPTF International
Director) (tim.halliday@homecall.co.uk). It lists papers on amphibian declines and
their causes and papers on amphibian conservation, with an emphasis on those
that describe methods for monitoring and conserving amphibian populations. Tim
is always delighted to receive details of forthcoming papers from their authors.
AmphibiaWeb: Information on amphibian biology and conservation. [web application].
2011. Berkeley, California: AmphibiaWeb. Available: http://amphibiaweb.org/.
(Accessed: September 11, 2011).
Austin, J. D. et al. (in press) Genetic
evidence of contemporary hybridization in
one of North America’s rarest anurans, the
Florida bog frog. Animal Conservation:
(austinj@ufl.edu)
Bancroft, B. A. et al. (2011) Specieslevel
correlates of susceptibility
to the pathogenic amphibian
fungus Batrachochytrium
dendrobatidis in the United
States. Biodiversity & Conservation: 20;
1911-1920.(betsybancroft@suu.edu)
Barker, B. S. et al. (in press) Deep
intra-island divergence of a montane
forest endemic: phylogeography of the
Puerto Rican frogEleutherodactylus
portoricensis (Anura:
Eletherodactylidae). J. Biogeography:
(barkerbr@unm.edu)
Belden, L. K. & Wojdak, J. M. (2011)
The combined influence of trematode
parasites and predatory salamanders
on wood frog (Rana sylvatica)
tadpoles. Oecologia: 166; 1077-1086.
(belden@vt.edu)
Bionda, C de L. et al. (2011) Composition
of amphibian assemblages in
agroecosystems from the central region of
Argentina. Russian J. Herpetol: 18; 93-
98. (cbionda@exa.unrc.edu.ar)
Boisvert, S. P. & Davidson, E. W.
(2011) Growth of the amphibian
pathogen, Batrachochytrium
dendrobatidis, in response to chemical
properties of the aquatic environment. J.
Wildlife Diseases: 47; 694-698.
(e.davidson@asu.edu)
48 | FrogLog Vol. 98 | September 2011