scholarly journals Frogs host faecal bacteria typically associated with humans

2017 ◽  
Vol 63 (7) ◽  
pp. 633-637 ◽  
Author(s):  
Karen Gibb ◽  
Xavier Schobben ◽  
Keith Christian

Tree frogs commonly access drinking water tanks; this may have human health implications. Although amphibians might not be expected to host mammalian faecal indicator bacteria (FIB), it is possible that they may have human FIB on their skin after exposure to human waste. We collected faeces and skin wash from green tree frogs (Litoria caerulea) from a natural environment, a suburban site, and a suburban site near a creek occasionally contaminated with sewage effluent. We used molecular techniques to test for FIB that are routinely used to indicate human faecal contamination. Enterococci colonies were isolated from both faecal and skin wash samples, and specific markers (Enterococcus faecium and Bacteroides thetaiotaomicron) were found in frog faeces, demonstrating that these markers are not human- or mammalian-specific. Bacteroides thetaiotaomicron was detected in frogs from both natural and urban sites, but E. faecium was only associated with the sewage impacted site.

2010 ◽  
Vol 41 (2) ◽  
pp. 242-248 ◽  
Author(s):  
Barbara Gericota ◽  
Michael M. Garner ◽  
Bradd Barr ◽  
Robert Nordhausen ◽  
R. Scott Larsen ◽  
...  

2006 ◽  
Vol 3 (10) ◽  
pp. 689-697 ◽  
Author(s):  
W Federle ◽  
W.J.P Barnes ◽  
W Baumgartner ◽  
P Drechsler ◽  
J.M Smith

Tree frogs are remarkable for their capacity to cling to smooth surfaces using large toe pads. The adhesive skin of tree frog toe pads is characterized by peg-studded hexagonal cells separated by deep channels into which mucus glands open. The pads are completely wetted with watery mucus, which led previous authors to suggest that attachment is solely due to capillary and viscous forces generated by the fluid-filled joint between the pad and the substrate. Here, we present evidence from single-toe force measurements, laser tweezer microrheometry of pad mucus and interference reflection microscopy of the contact zone in Litoria caerulea , that tree frog attachment forces are significantly enhanced by close contacts and boundary friction between the pad epidermis and the substrate, facilitated by the highly regular pad microstructure.


2010 ◽  
Vol 62 (3) ◽  
pp. 586-593 ◽  
Author(s):  
P. Roslev ◽  
A. S. Bukh ◽  
L. Iversen ◽  
H. Sønderbo ◽  
N. Iversen

Sources of faecal pollution in coastal recreational waters may be identified by analysing different host associated microorganisms or molecular markers. However, the microbial targets are often present at low numbers in moderately impacted waters, and often exhibit significant temporal and spatial variability in waters with fluctuating faecal loads. This patchy occurrence can limit successful detection of relevant targets in microbial source tracking studies. In this study, we explored the possibility for using the blue mussel (Mytilus edulis) as a biosampler for accumulation of faecal bacteria relevant for microbial source tracking. Non-contaminated blue mussels were transferred to three coastal recreational waters affected by faecal pollution of unknown origin. Molecular markers associated with animal and human waste were targeted by PCR and compared in seawater and mussel samples. The results demonstrated that transplanted mussels in simple enclosures accumulated and retained elevated levels of molecular markers associated with different types of faecal pollution. The targets included a novel putative human associated E. coli subgroup B2 VIII clone, and animal and human associated markers in enterococci (esp, M19, M66, M90, and M91). Human (sewage) associated markers including esp and M66 were sometimes not detectable in seawater samples despite known wastewater contamination, whereas the markers were detectable in mussels. We suggest that transplanted mussels should be considered as potential biosamplers in studies focusing on identifying source of faecal pollution in low or moderately impacted recreational waters. Bioaccumulation of molecular markers in mussels for several days may represent the water quality better than traditional grab samples from the water column.


1999 ◽  
Vol 11 (2) ◽  
pp. 194-199 ◽  
Author(s):  
Allan P. Pessier ◽  
Donald K. Nichols ◽  
Joyce E. Longcore ◽  
Melvin S. Fuller
Keyword(s):  

2020 ◽  
Vol 30 (1) ◽  
pp. 38
Author(s):  
Ashley R. Krisp ◽  
Jennifer C. Hausmann ◽  
Kurt K. Sladky ◽  
Christoph Mans
Keyword(s):  

2016 ◽  
Vol 7 ◽  
pp. 2116-2131 ◽  
Author(s):  
Niall Crawford ◽  
Thomas Endlein ◽  
Jonathan T Pham ◽  
Mathis Riehle ◽  
W Jon P Barnes

Tree frogs need to adhere to surfaces of various roughnesses in their natural habitats; these include bark, leaves and rocks. Rough surfaces can alter the effectiveness of their toe pads, due to factors such as a change of real contact area and abrasion of the pad epithelium. Here, we tested the effect of surface roughness on the attachment abilities of the tree frog Litoria caerulea. This was done by testing shear and adhesive forces on artificial surfaces with controlled roughness, both on single toe pads and whole animal scales. It was shown that frogs can stick 2–3 times better on small scale roughnesses (3–6 µm asperities), producing higher adhesive and frictional forces, but relatively poorly on the larger scale roughnesses tested (58.5–562.5 µm asperities). Our experiments suggested that, on such surfaces, the pads secrete insufficient fluid to fill the space under the pad, leaving air pockets that would significantly reduce the Laplace pressure component of capillarity. Therefore, we measured how well the adhesive toe pad would conform to spherical asperities of known sizes using interference reflection microscopy. Based on experiments where the conformation of the pad to individual asperities was examined microscopically, our calculations indicate that the pad epithelium has a low elastic modulus, making it highly deformable.


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