Behaviour, Disease, and the MHC of Amphibians

Bruce Waldman 한국양서·파충류학회 2011 한국양서·파충류학회 학술대회 Vol.2011 No.1

Skin microbiome diversity of Asiatic toad (Bufo gargarizans) and its association with differential immune response to Batrachochytrium dendrobatidis infection and animal behaviour

Ramasamy Dhamodharan,Bruce Waldman 한국양서·파충류학회 2016 한국양서·파충류학회 학술대회 Vol.2016 No.07

Chytridiomycosis is a devastating disease that causes a decline in the amphibian population (Stuart et al., 2004) worldwide. Recently, the fungus, Batrachochytrium dendrobatidis (Bd) emerged as one of the greatest threats to biodiversity due to its ability to affect amphibian species across all continents (James et al., 2015). A growing number of studies have examined the role of amphibian adaptive immunity in response to this pathogen, with varying degrees of immune activation (Carey et al., 1999). Variations in the susceptibility of B. gargarizans to chytridiomycosis, pathogen virulence, and environmental factors have been well documented (Tobler and Schmidt 2010). Anurans infected with B. dendrobatidis also change its mate choice, a choice which is significantly determined by the genetic variation in the major histocompatibility complex (MHC) molecules of the host. Furthermore, it is known that the MHC gene polymorphism also contributes to chytridiomycosis resistance (Savage et al., 2011; Bataille et al., 2015). Amphibians are host to a diverse community of microbes on their skin and some of the bacterial species are known to protect their host from the lethal fungal pathogen B. dendrobatidis, by secreting antifungal metabolites (Becker et al., 2015). Recently, microbiome variation across amphibian skin regions has been reported (Bataille et al., 2016) but there are no reports on the role of the skin microbiome and its relationship with Bd resistance and animal behaviour of B. gargarizans. The objectives of this study are to characterize the skin microbiome diversity of B. gargarizans collected from two locations in South Korea, and to correlate with MHC diversity, Bd resistance and animal behaviour (mating choice). In order to analyse the skin microbiome diversity, metagenomics sequencing of 16S rRNA will be used. Exploring the skin microbiome diversity of B. gargarizans would be useful for understanding the differential immune response to B. dendrobatidis. The results of the study may also help us understand the association of different selection pressures (geographical variation, nutrition, pesticides, antibiotics, and other environmental factors) in the evolution of host-microbial diversity and virulence. The findings will contribute to our understanding of how host immune system and symbiotic bacteria interact to confer disease resistance and provide cues used in mate choice that is important in maintaining immunogenetic variation within populations.

도롱뇽(Hynobius leechii) 유생의 공격성

Samantha Wojciechowski,Bruce Waldman 한국양서·파충류학회 2013 한국양서·파충류학회 학술대회 Vol.2013 No.1

무당개구리(Bombina orientalis)의 계통지리 연구

Jonathan J. Fong,민미숙,Bruce Waldman 한국양서·파충류학회 2014 한국양서·파충류학회 학술대회 Vol.2014 No.07

Batrachochytrium salamandrivorans 가 도롱뇽(Hynobius leechii)과 이끼도롱뇽(Karsenia koreana)의 성장과 생존에 미치는 영향

이은선,전종윤,김주완,Bruce Waldman 한국양서·파충류학회 2018 한국양서·파충류학회 학술대회 Vol.2018 No.07

1990년대 말, 전 세계적으로 많은 양서류 개체군의 크기를 급감시킨 항아리곰팡이 (Batrachochytrium dendrobatidis, Bd)가 발견되었다. 해당 곰팡이는 개구리 등의 무미목 과 도롱뇽 등의 유미목 모두를 감염시키는 종으로, 발견 이후 이에 대한 여러 종의 감염 여부 및 취약성을 확인하는 연구가 진행되었다. 2010년대에 이르러, 유미목만을 감염시켜 이에 취약한 종은 죽음에 이르게 하는 Batrachochytrium salamandrivorans (Bsal) 이 추가로 발견되었다. Bd의 국내 발견과는 달리 Bsal은 아직 국내에서 발견되 었다는 보고가 없다. 이에 우리나라 도롱뇽 (Hynobius leechii)과 이끼도롱뇽 (Karsenia koreana)을 대상으로 Bsal에 대한 취약성 연구를 진행하였다. 감염을 위해 도롱뇽의 준성체와 성체, 이끼도롱뇽의 성체를 각 비슷한 크기의 실험군과 대조군으로 나누었 다. 이후 2018년 4월과 5월에 걸쳐 연구실 내 배양한 곰팡이의 일정량을 따내 감염 을 진행하였다. 감염 이후 5주간 매일 각 개체의 피부 병변 등을 확인하였고, 개체별 snout-vent length (SVL), total length (TL), 무게를 감염 전과 5주 이후 측정, 비교하 여 감염의 영향을 확인하였다. 실험 결과 해당 곰팡이가 도롱뇽과 이끼도롱뇽 모두 에게 치명적이지 않으며, 개체의 길이나 무게에도 유의미한 영향을 주지 않아 취약 성이 없는 것으로 확인되었다. 향후 유전자증폭을 이용한 연구 등을 통해, 해당 곰팡 이의 감염 이후 피부 조직 내 곰팡이의 양이 어떻게 변화하는지를 확인하여 저항성 의 특성을 깊게 파악하는 연구가 필요할 것으로 생각된다. 또한, Bsal뿐 아니라 Bd Global Panzootic Lineage(Bd GPL) 등 여러 계통에의 감염성 연구도 이뤄져야 할 것이다.

Effects of Three Fire-Suppressant Foams on the Germination and Physiological Responses of Plants

Song, Uhram,Mun, Saeromi,Waldman, Bruce,Lee, Eun Ju Springer-Verlag 2014 Environmental management Vol.54 No.4

Ecological immunogenetics of life-history traits in a model amphibian

Barribeau, Seth M.,Villinger, Jandouwe,Waldman, Bruce The Royal Society 2012 Biology letters Vol.8 No.3

<P>Major histocompatibility complex (MHC) genes determine immune repertoires and social preferences of vertebrates. Immunological regulation of microbial assemblages associated with individuals influences their sociality, and should also affect their life-history traits. We exposed <I>Xenopus laevis</I> tadpoles to water conditioned by adult conspecifics. Then, we analysed tadpole growth, development and survivorship as a function of MHC class I and class II peptide-binding region amino acid sequence similarities between tadpoles and frogs that conditioned the water to which they were exposed. Tadpoles approached metamorphosis earlier and suffered greater mortality when exposed to immunogenetically dissimilar frogs. The results suggest that developmental regulatory cues, microbial assemblages or both are specific to MHC genotypes. Tadpoles may associate with conspecifics with which they share microbiota to which their genotypes are well adapted.</P>

Lack of Bsal in South Korea

Samantha Garza,Mi-Sook Min,Bruce Waldman 한국양서·파충류학회 2017 한국양서·파충류학회 학술대회 Vol.2017 No.07

Chytridiomycosis is often associated with die-offs of amphibians worldwide. Two species of amphibian chytrid fungus, Batrachochytrium dendrobatidis (Bd) and Batrachochytrium salamandrivorans (Bsal), have been known to kill amphibians. Most attention has been on Bd, until Bsal was discovered in The Netherlands in 2013 and is considered the responsible agent for massive die-offs in salamanders there. Bd is thought to have originated from Asia, and scientists hypothesize Bsal also originates from Asia. To determine if Bsal is present In South Korea, we swabbed over 200 salamanders from 24 different sites over 2 years. We surveyed 5 salamander species in the genus Hynobius ; over 100 individuals of Hynobius leechii, 20 individuals of Hynobius quelpaertensis, 35 individuals of Hynobius yangi, and 10 individuals Hynobius unisacculus. We also surveyed 61 individuals of the Korean crevice salamander, Karsenia koreana. We swabbed the ventrum and toes of the salamanders. We extracted DNA using Prepman Ultra, and used a Bsal specific primers in a PCR. No Bsal has been detected in any sample screened so far. Thus we suspect that Bsal is not endemic to South Korea, and may pose a threat if it is introduced. This work was supported by a grant from the National Research Foundation of Korea (NRF) funded by the Ministry of Education (NRF-2016R1D1A1B03934071) and National Geographic Society.

Multiple major histocompatibility complex class I genes in Asian anurans: Ontogeny and phylogeny

Didinger, Chelsea,Eimes, John A.,Lillie, Mette,Waldman, Bruce Elsevier 2017 DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY Vol.70 No.-

<P><B>Abstract</B></P> <P>Amphibians, as the first terrestrial vertebrates, offer a window into early major histocompatibility complex (MHC) evolution. We characterized the MHC class I of two Korean amphibians, the Asiatic toad (<I>Bufo gargarizans</I>) and the Japanese tree frog (<I>Hyla japonica</I>). We found at least four transcribed MHC class I (MHC I) loci, the highest number confirmed in any anuran to date. Furthermore, we identified MHC I transcripts in terrestrial adults, and possibly in aquatic larvae, of both species. We conducted a phylogenetic analysis based on MHC I sequence data and found that <I>B. gargarizans</I> and <I>H. japonica</I> cluster together in the superfamily Nobleobatrachia. We further identified three supertypes shared by the two species. Our results reveal substantial variation in the number of MHC I loci in anurans and suggest that certain supertypes have particular physiochemical properties that may confer pathogen resistance.</P> <P><B>Highlights</B></P> <P> <UL> <LI> We describe, for the first time, sequences of MHC class I from the Asian frogs <I>Bufo gargarizans</I> and <I>Hyla japonica.</I> </LI> <LI> We found at least four transcribed MHC class I loci in each species. </LI> <LI> MHC I transcription was found in larvae as well as adults. </LI> <LI> The two species shared supertypes based on their MHC I sequences. </LI> </UL> </P>

Characterization of MHC class IA in the endangered southern corroboree frog

Kosch, Tiffany A.,Eimes, John A.,Didinger, Chelsea,Brannelly, Laura A.,Waldman, Bruce,Berger, Lee,Skerratt, Lee F. Springer-Verlag 2017 Immunogenetics Vol.69 No.3

<P>Southern corroboree frogs (Pseudophryne corroboree) have declined to near extinction in the wild after the emergence of the amphibian chytrid fungus Batrachochytrium dendrobatidis in southeastern Australia in the 1980s. A major captive breeding and reintroduction program is underway to preserve this iconic species, but improving resistance to B. dendrobatidis would help the wild population to be self-sustaining. Using 3' and 5' rapid amplification of complementary DNA ends (RACE), we characterized the major histocompatibility complex (MHC) class IA locus in this species. We then used sequences generated from RACE to design primers to amplify the peptide-binding region (PBR) of this functional genetic marker. Finally, we analysed the diversity, phylogeny, and selection patterns of PBR sequences from four P. corroboree populations and compared this with other amphibian species. We found moderately high MHC class IA genetic diversity in this species and evidence of strong positive and purifying selection at sites that are associated with putative PBR pockets in other species, indicating that this gene region may be under selection for resistance to Bd. Future studies should focus on identifying alleles associated with Bd resistance in P. corroboree by performing a Bd laboratory challenge study to confirm the functional importance of our genetic findings and explore their use in artificial selection or genetic engineering to increase resistance to chytridiomycosis.</P>