Yeasts Occurring in Surface and Mouth Cavity of Two Chelonian Species, Podocnemis expansa Schweigger and P. unifilis Troschel (Reptilia: Chelonia: Pelomedusidae), in the Javaés River Border of Araguaia National Park in Brazil
Thirty-eight specimens of free-ranging Podocnemis expansa (Amazon turtle) and 22 of P. unifilis (Tracajá) were screened for yeast isolation from surface (plastron, skin, and nails), eye, and mouth cavity. A hundred and eighteen yeast isolates belonging to 39 species were obtained. Debaryomyces hansenii, Candida galli, C. sake, and Rhodotorula mucilaginosa were the most frequent species isolated from these chelonians. Species diversity measured by Shannon's index was shown to be low and a degree of dominance could be detected as species known as potential pathogens were commonly isolated. The effective number of species in plastron of P. expansa was higher than in mouth samples, but not in P. unifilis probably due to dietary factors. P. expansa animals were captured on the beaches, and the superficial yeast populations may include terrestrial species. P. unifilis animals were captured in the water and the yeasts from superficial sites may represent species from river water. 1. Introduction According to Summerbell , an important component of the fungal biodiversity of any given area occurs in habitats defined or conditioned primarily by vertebrates. Such habitats include the animals themselves which are colonized by commensals and disease-causing fungi, as well as organic materials making up dwelling places of those animals. Jones et al.  have studied fungi occurring in fecal samples of the Eastern box turtle (Terrapene carolina carolina), a facultative mycovore reptile that may play an important role in fungal spore dispersion. These authors isolated two yeasts, Cryptococcus albidus and Rhodotorula mucilaginosa, that are reported to naturally occur on Trifolium seeds found in fecal samples. Pathogenic interactions are mostly opportunistic  and yeasts present a variety of hosts [4–9]). Kostka et al.  did postmortem examination in 91 reptiles that revealed that the intestines of 80.6% of the animals carried yeasts. The authors found 56 yeast isolates belonging to the genera Candida (39), Trichosporon (13), Torulopsis (9), and Rhodotorula (3), and one nonidentified teleomorph yeast species. However, they point that no sufficiently reliable criteria could be established to prove that yeasts are associated with disease in reptiles. Erosion and traumatic lesions are common in scutelum and plastron of aquatic turtles that may be caused by algae, bacteria, and fungi . We studied the yeasts occurring in Podocnemis expansa (Amazon turtle) and Podocnemis unifilis (Tracajá), reptiles of Testudines family that occur in the rivers of Araguaia Plains,
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