scholarly journals Exposure to a fungal pathogen increases the critical thermal minimum of two frog species

2021 ◽  
Author(s):  
Spencer R. Siddons ◽  
Catherine L. Searle
2017 ◽  
Vol 67 (4) ◽  
pp. 525-539
Author(s):  
Somporn Techangamsuwan ◽  
Angkana Sommanustweechai ◽  
Sumate Kamolnorranart ◽  
Boripat Siriaroonrat ◽  
Wichase Khonsue ◽  
...  

AbstractChytridiomycosis, a disease in amphibians caused by Batrachochytrium dendrobatidis (Bd), has led to a population decline and extinction of frog species since 1996. The objective of this study was to determine the prevalence of and the need for establishing a surveillance system for monitoring chytridiomycosis in five national zoos and five free ranging protected areas across Thailand. A total of 492 skin swab samples were collected from live and dead animals and tested by polymerase chain reaction (PCR) for the presence of Bd. The positive specimens were confi rmed by amplicon sequencing and examined by histopathology and immunohistochemistry. From July 2009 to August 2012, the prevalence of Bd from frog skin samples was low (4.27%), monitored by PCR. All samples from live amphibians were negative. The positive cases were only from dead specimens (21/168, 12.5% dead samples) of two non-native captive species, poison dart frog (Dendrobates tinctorius) and tomato frog (Dyscophus antongilii) in one zoo. Immunohistochemistry and histopathology revealed the typical feature of fl ask-shaped zoosporangia and septate thalli, supporting the PCR-based evidence of chytridiomycosis in captive amphibians in Thailand, but detected Bd in only 7/21 of the PCR-positive samples. Although the introduction of a pathogenic strain of Bd from imported carriers might have a serious impact on the native amphibian populations in Thailand, chytridiomycosis has not currently been detected in native Thai amphibians. An active surveillance system is needed for close monitoring of the fungus crossing into Thai amphibian populations


Author(s):  
H.M. Mazzone ◽  
G. Wray ◽  
R. Zerillo

The fungal pathogen of the Dutch elm disease (DED), Ceratocystis ulmi (Buisman) C. Moreau, has eluded effective control since its introduction in the United States more than sixty years ago. Our studies on DED include establishing biological control agents against C. ulmi. In this report we describe the inhibitory action of the antibiotic polymyxin B on the causal agent of DED.In screening a number of antibiotics against C. ulmi, we observed that filter paper discs containing 300 units (U) of polymyxin B (Difco Laboratories) per disc, produced zones of inhibition to the fungus grown on potato dextrose agar or Sabouraud agar plates (100mm x 15mm), Fig. 1a. Total inhibition of fungal growth on a plate occurred when agar overlays containing fungus and antibiotic (polymyxin B sulfate, ICN Pharmaceuticals, Inc.) were poured on the underlying agar growth medium. The agar overlays consisted of the following: 4.5 ml of 0.7% agar, 0.5 ml of fungus (control plate); 4.0 ml of 0.7% agar, 0.5 ml of fungus, 0.5 ml of polymyxin B sulfate (77,700 U). Fig. 1, b and c, compares a control plate and polymyxin plate after seven days.


2017 ◽  
Vol 11 (1) ◽  

The Taal Volcano Protected Landscape (TVPL) encompasses a prehistoric volcano caldera that caters to many documented endemic species. Although regarded as a unique area with the potential to house a diverse ecological community, biodiversity research in TVPL is still found wanting. The present paper aims to provide baseline information and increase research interests on the herpetofaunal diversity of TVPL, in light of its many undocumented terrestrial faunal species. Twelve study sites within the municipalities of Tanauan, Mataasnakahoy, and Balete were visited during survey trips from May to November 2015. A combination of transect and opportunistic sampling techniques were utilized, with morphometric data and sexual maturity recorded for each specimen collected. This preliminary survey provided 24 newly documented species of amphibians and reptiles occurring within TVPL. A total 10 frog species (from families Bufonidae, Ceratobatrachidae, Microhylidae, Dicroglossidae, Ranidae, and Rhacophoridae) and 14 reptile species (from families Agamidae, Gekkonidae, Scincidae, Varanidae, Acrochordidae, Colubridae, Elapidae, and Tryonychidae) were documented. Of the reptiles recorded, 3 are endemic species and widespread throughout the Philippines: Gekko mindorensis, Hydrosaurus pustulatus, and Draco spilopterus. Also recorded were the Philippine endemic frogs Kaloula picta and Limnonectes woodworthi along with the Luzon endemics Platymantis mimulus and Varanus marmoratus. The species-effort curve of amphibians showed a distinct plateau whereas the species-effort curve of reptiles has shown an increasing trend suggesting that additional sampling efforts should be done in the area to further increase knowledge of the TVPL herpetofaunal diversity.


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