Members of the genus Basidiobolus, a saprophytic fungus, have been associated with the digestive tracts of a wide variety of amphibians and reptiles. To elucidate the relationship of Basidiobolus sp. with amphibians in central Florida (USA), we document the occurrence of the fungus in the digestive tracts of Bufo terrestris, Buffo quercicus, Hyla femoralis, Hyla cinerea, Hyla gratiosa, Hyla squirella, Osteopilus septentrionalis, and Rana utricularia. Species that occupy terrestrial habitats (B. terrestris, B. quercicus, and R. utricularis) were found to harbor Basidiobolus spp. more frequently (83, 78, and 91%, respectively) than those that occupied a more arboreal habitat (H. cinerea, H. squirella, H. femoralis, H. gratiosa, and O. septentrionalis (50, 56, 55, 56, and 70%, respectively).

In an effort to begin to understand the basic population structure of Basidiobolus, a single, nonlongitudinal field study was conducted to shed light on the number and distribution of the fungus in the soil and litter from several locations near the University of South Florida (USF) in Tampa, Florida. The occurrence of the related fungus Conidiobolus was also documented for comparison with previous studies. An undisturbed cypress stand, an open grassy area on the campus of USF and two pasture lands were chosen for study. Four isolations of Basidiobolus and 48 of Conidiobolus were obtained from 125 soil samples taken from the 5 study plots. Additional samples of soil were taken from the area immediately surrounding the locations of two positive soil collections. One additional isolate of Basidiobolus was recovered from each of these samplings. RAPD analysis indicates that each Basidiobolus isolate is genetically unique and thus show no evidence of clonal growth in soil. This study suggests the conclusion that in some cases the intestines of reptiles and perhaps other animals may be a more significant reservoir for Basidiobolus than the soil.

ABSTRACTGenetic variation and its distribution among populations and putative species of 70 isolates in the genus Basidiobolus were analyzed by means of electrophoretic analysis of soluble enzymes. Five enzyme systems were examined and showed large variation. Among laboratory isolates, only one of B. microspore could be distinguished by means of cluster analysis. Patterns of variation among natural isolates revealed little differentiation with respect to host (toad vs lizard), but very strong patterns of geographical differentiation. Furthermore, natural isolates were quite distinct from laboratory strains tested. These results suggest that the genus Basidiobolus is genetically very heterogeneous, and this fact may contribute to difficulties encountered in defining taxonomic relationships.Key Words: EntomophthoralesBasidiobolusgenetic variationpopulationsisozymes

Journal of Fish DiseasesVolume 12, Issue 2 p. 175-178 Ulcerative mycosis: a serious menhaden disease of the southeastern coastal fisheries of the United States M. J. DYKSTRA, Corresponding Author M. J. DYKSTRA School of Veterinary Medicine, North Carolina State University, Raleigh, North Carolina, USADr M. J. Dykstra, School of Veterinary Medicine, North Carolina State University, Raleigh, North Carolina 27606, USA.Search for more papers by this authorJ. F. LEVINE, J. F. LEVINE School of Veterinary Medicine, North Carolina State University, Raleigh, North Carolina, USASearch for more papers by this authorE. J. NOGA, E. J. NOGA School of Veterinary Medicine, North Carolina State University, Raleigh, North Carolina, USASearch for more papers by this authorJ. H. HAWKINS, J. H. HAWKINS North Carolina Division of Marine Fisheries, Washington, North Carolina, USASearch for more papers by this authorP. GERDES, P. GERDES Virginia Institute of Marine Science, Gloucester Point, Virginia, USASearch for more papers by this authorW. J. HARGIS JR, W. J. HARGIS JR Virginia Institute of Marine Science, Gloucester Point, Virginia, USASearch for more papers by this authorH. J. GRIER, H. J. GRIER Bureau of Marine Research, St Petersburg, Florida, USASearch for more papers by this authorD. TE STRAKE, D. TE STRAKE Department of Biology, University of South Florida, Tampa, Florida, USASearch for more papers by this author M. J. DYKSTRA, Corresponding Author M. J. DYKSTRA School of Veterinary Medicine, North Carolina State University, Raleigh, North Carolina, USADr M. J. Dykstra, School of Veterinary Medicine, North Carolina State University, Raleigh, North Carolina 27606, USA.Search for more papers by this authorJ. F. LEVINE, J. F. LEVINE School of Veterinary Medicine, North Carolina State University, Raleigh, North Carolina, USASearch for more papers by this authorE. J. NOGA, E. J. NOGA School of Veterinary Medicine, North Carolina State University, Raleigh, North Carolina, USASearch for more papers by this authorJ. H. HAWKINS, J. H. HAWKINS North Carolina Division of Marine Fisheries, Washington, North Carolina, USASearch for more papers by this authorP. GERDES, P. GERDES Virginia Institute of Marine Science, Gloucester Point, Virginia, USASearch for more papers by this authorW. J. HARGIS JR, W. J. HARGIS JR Virginia Institute of Marine Science, Gloucester Point, Virginia, USASearch for more papers by this authorH. J. GRIER, H. J. GRIER Bureau of Marine Research, St Petersburg, Florida, USASearch for more papers by this authorD. TE STRAKE, D. TE STRAKE Department of Biology, University of South Florida, Tampa, Florida, USASearch for more papers by this author First published: March 1989 https://doi.org/10.1111/j.1365-2761.1989.tb00289.xCitations: 39AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Citing Literature Volume12, Issue2March 1989Pages 175-178 RelatedInformation

A dematiaceous fungus, Phialophora richardsiae (Nannf.) Conant, was isolated from human bone. In culture the fungus produced no yeast forms and was less pigmented than two other P. richardsiae isolates. While growth rates were similar, colonial forms differed. Phialides were of two kinds. While both had broad bases and tapered at the tips, only one terminated with a cupulate or rarely a saucer-shaped collarette. Most phialides were hyaline with a few lightly pigmented ones in older cultures. Broth dilution susceptibility testing of the isolates against amphotericin B, miconazole, ketoconazole, clotrimazole, and 5-fluorocytosine showed the fungus was susceptible to miconazole, ketoconazole and amphotericin B at achievable serum levels and resistant to 5-fluorocytosine and clotrimazole. The other isolates were reported to differ in their resistance to miconazole and amphotericin B. Enzyme and salinity studies showed minor difference among the isolates.

To provide information about the distribution of a Basidiobolus sp., an occasional pathogen in the subtropics and tropics, 95 reptiles and amphibians, comprising eight different species, were trapped from the beaches and inland habitats of Tampa and Miami, Florida. Five of the eight animal species were infested with Basidiobolus sp. Approximately 50% of the animals collected carried this zygomycete. Under laboratory conditions, it remained in the digestive tracts of some starved anoles for up to 3 weeks. Some animals, whose digestive tract was fungus-free, could be colonized with the Basidiobolus sp. by feeding them mealworms contaminated with propagules of this fungus. This finding alters, in a minor way, the present concept of the life history of the fungus.

Fungistasis which occurs in soil has also been reported to exist in seawater. Nannochloris sp. (Chlorophyta) found along the west coast of Florida, has been shown to elaborate a compound which is cytolytic towards Ptychodiscus brevis, the Florida red tide organism. Aponin, a chloroform extract containing the cytolytic compound or compounds, was tested on the spore germination of two fungi, Dendryphiella salina, a facultative marine organism and Curvularia sp. a terrestrial one. Aponin was stimulatory towards D. salina at all concentrations tested, while Curvularia sp. was stimulated at the highest concentration used but inhibited at the lower concentrations. The culture age of the two fungi did not alter the relative sensitivity of both fungi towards aponin but the germination percentage of Curvularia sp. was affected by the culture age. An aqueous extract of Nannochloris sp. was also tested on the two fungi and was shown to be inhibitory to both. The results seem to indicate that more than one compound from Nannochloris sp. is capable of affecting spore germination indicating that this alga might be playing a role in the reported fungistasis in seawater. Gulf seawater was tested and found to have little if any fungistatic activity.

The in vitro activities of amphotericin B, miconazole, ketoconazole, 5-fluorocytosine, and potassium iodide (KI) were studied on human and wild-type isolates of Basidiobolus and Conidiobolus species. Of the antifungal agents tested, the imidazole derivatives, especially ketoconazole, were the most active against the agents of entomophthoromycosis. Transmission electron microscopy showed severe morphological alteration of Basidiobolus sp. exposed to 0.78 micrograms of ketoconazole per ml. The MIC and minimal fungicidal concentration of ketoconazole was often lowered in the presence of 10% fetal calf serum or antibiotic medium no. 3. Half of the Basidiobolus isolates and all Conidiobolus isolates were inhibited by amphotericin B at 0.39 micrograms/ml. None of the strains tested were inhibited or killed at maximum concentrations of 5-fluorocytosine and KI. The in vitro resistance of these fungi to KI at high concentrations suggests that the reported favorable treatment with KI may not be due to its direct effect on these fungi but rather to other, undefined factors in combination with KI. These data suggest that ketoconazole may be of use in the treatment of entomophthoromycosis, particularly in cases which are not responsive to KI.