A Variety of Fungal Species on the Green Frogs' Skin (Pelophylax esculentus complex) in South Banat

MALDI-TOF Mass Spectrometry Characterization of Culturable Microbiota Associated with the Skin of Amphibians from the Southern Andes Mountains of Ecuador

Ecuador is recognized for having a high diversity of anuran species, which are distributed mainly south of the Andes mountains. However, due to their geographic location and accessibility, there are few studies related to the culturable microbiota of these amphibians in this region. The objective of this study was to explore the bacterial and fungal biodiversity present on the skin of wild anuran species in the southern Andes of Ecuador and to observe whether geographical barriers in the region could increase the variability of the culturable microbiota through MALDI-TOF mass spectrometry. This analysis revealed the presence of 29 bacterial taxa and 9 fungal taxa, consisting mainly of: Pseudomonas chlororaphis (28%), Acinetobacter iwoffii (14%), Pseudomonas fluorescens (14%), and Hortaea werneckii (26.4%), Fusarium solani (20.5%), Syncephalastrum spp. (20.5%), respectively. Diversity varied across the five sampling locations, with geographic location proving to be a significant driver of diversity. Some of the most abundant bacterial and fungal genera have important associations with skin diseases in wildlife and humans. This work represents a glimpse into the complex biodiversity of bacteria and fungi that inhabit the skin substrate, and further studies will be needed to better understand bacterial and fungal biodiversity with potential implications for establishing conservation strategies, along with the development of necessary animal protection measures.

More Than Meets the Eye: Unraveling the Interactions Between Skin Microbiota and Habitat in an Opportunistic Amphibian

With amphibians still holding the record as the most threatened class of terrestrial vertebrates, their skin microbiota has been shown to play a relevant role in their survival in a fast-changing world. Yet little is known about how abiotic factors associated with different aquatic habitats impact these skin microorganisms. Here we chose the yellow-bellied toad (Bombina variegata), a small anuran that colonizes a wide range of wetland habitats, to investigate how the diversity and composition of both its bacterial and fungal skin communities vary across different habitats and with water characteristics (temperature, pH, and dissolved oxygen) of these habitats. Skin microbiota was sampled from 14 sites in the Province of Trento (Italy), including natural pools, ephemeral ponds, irrigation tanks, and farm ponds. Interestingly, the diversity of the two microbial components was also highly correlated. Close associations between both the diversity and composition of water and skin communities were noted for each habitat and sampling site, suggesting that water bodies actively contribute to the skin microbiota assemblage. In addition, water pH, temperature, and dissolved oxygen affected both bacterial and fungal diversity of skin. We confirmed the presence of Batrachochytrium dendrobatidis in skin samples of animals collected from eight waterbodies, as well as more than 60 microbial taxa previously associated with resistance to this pathogen. We concluded that both skin bacterial and fungal communities appear to be influenced by each other as well as by environmental communities and conditions, and these relationships connecting the whole ecosystem should be considered in future research concerning amphibian conservation.

Mineral profile and histopathological findings in the liver of white-lipped frog (Leptodactylidae) from the morphoclimatic domain of the Caatingas, Brazil

This study aimed to investigate the mineral profile and histopathological findings in the liver of Leptodactylus macrosternum (white-lipped frog) and to assess the association between melanomacrophage areas and hepatic fungal granuloma with several factors such as weight, snout-cloacal length, sex, hepatosomatic index, season (dry and rainy), and condition factor K. A total of 135 frogs of different ages were collected from three areas in the city of Petrolina, Pernambuco, with varying land use (conventional agriculture, organic agriculture, and Caatinga stricto sensu). The liver of all specimens exhibited changes such as granulomatous lesions, inflammatory cell infiltrate, blood vessel congestion, and sinusoid dilation. The melanomacrophage areas were influenced by weight, snout-cloacal length, and hepatosomatic index. Our findings revealed a positive correlation between body size (weight and snout-cloacal length) and melanomacrophage/hepatic granuloma, while the hepatosomatic index showed a negative relationship. For the condition factor K, only age presents relationship. Eleven elements were quantified for the mineral profile, with aluminum (Al), iron (Fe), and zinc (Zn) being the most abundant in both liver and muscle. Although the histopathological findings and mineral profile of the liver and muscle in this study indicate an effect on the health of L. macrosternum in different collection areas, confirming the relationship between environmental characteristics and these findings requires future studies. Furthermore, long-term studies would be necessary to allow the monitoring of all stages of development of these populations, from tadpoles to adults, for a better evaluation of these effects in L. macrosternum.