Assays on the amphibian Chytrid fungus at Crocker Range, Sabah
Global amphibian population decline is happening at an alarming rate. Comparatively, anurans (Amphibia: Anura) face greater risk due to its greater representation in the Class Amphibia, and wider distribution throughout the Earth. Batrachochytrium dendrobatldis (Bd), the amphibian chytrid fungus, ha...
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| Format: | Thesis |
| Language: | English English |
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2012
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| Online Access: | https://eprints.ums.edu.my/id/eprint/41714/2/ABSTRACT.pdf https://eprints.ums.edu.my/id/eprint/41714/1/FULLTEXT.pdf |
| Summary: | Global amphibian population decline is happening at an alarming rate. Comparatively, anurans (Amphibia: Anura) face greater risk due to its greater representation in the Class Amphibia, and wider distribution throughout the Earth. Batrachochytrium dendrobatldis (Bd), the amphibian chytrid fungus, has been associated with the dramatic decline of amphibian and anuran populations globally. Thus, a study on the prevalence of the amphibian chytrid fungus on anuran population becomes imperative. The objectives of this study were (i) to investigate the prevalence of amphibian chytrid fungus, Bd, on anuran species at Crocker Range, Sabah and (ii) to assess the species composition of general fungal microflora on anuran species at Crocker Range. The study was conducted in Crocker Range which encompasses Crocker Range Park (CRP) and Kinabalu National Park (KNP). The altitude of the sampling sites ranged from 120 - 3,242 m a.s.l., temperatures ranged from 9 - 31°C, and relative humidity ranged from 53 - 100%. Opportunistic examination was applied in anuran sampling. Swab-Polymerase Chain Reaction (PCR) approach was used to detect Bci. Swab-culture-based and PCR assay were used to isolate and identify the general fungal microflora from anuran skin. A total of 418 adult anurans representing 36 species, 17 genera and five families were collected. As for larval anurans, 298 larvae of Hylarana sp., Leptobrachium sp., Meristogenys sp., and Rhacophorus sp. were collected. A total of 507 specimens of anurans representing 418 wild adults, nine adult Lithobates catesbianus, 80 larvae with depigmented mouthpart, and three dead anurans were analysed for Bd presence. All collected anuran species were tested negative for Bd DNA. The reason for the absence of Bd in anurans at both Parks could be affected by temperature, altitude, latitude, and seasons, and varied response among anuran species towards Bd infection. Factors such as host age, innate defense such as the production of antimicrobial peptides, proportion of anti-chytrid microbes, and strains of Bd itself could also influence the prevalence of Bd. The lack of baseline information on the susceptibility of the sampled species to Bd infection is also preventing a definite conclusion regarding the absence of Bd in CRP and KNP to be drawn. A total of 19 genera of fungi representing 15 families and six classes from two phyla, namely Ascomycota and Basidiomycota, were identified from anuran skin. Further studies on the prevalence of Bd, and general fungal microflora on anuran species need to be conducted throughout Sabah, Borneo, and Malaysia. |
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