Environmental DNA (eDNA) is the genetic material that organisms leave in the environment. In this study, we collected water samples from four isolated wetlands in the Francis Marion National Forest in the winter (January) and spring (March), extracted environmental DNA (eDNA) and used species-specific mitochondrial genes to identify the presence of rare amphibian species. Currently, our target genes are COI (Cytochrome C Oxidase Subunit I) and ND2 (Subunit of NADH dehydrogenase). Our target species is the rare Gopher Frog (Lithobates capito), a fossorial species that emerges from upland longleaf pine habitats to breed in isolated temporary ponds after heavy rains. In addition, we are testing for the presence of potentially co-occurring species of the longleaf pine isolated wetlands (Southern Leopard Frog - Lithobates sphenocephalus, Southern Toad - Anaxyrus terrestris, Southern Chorus Frog - Pseudacris nigrita, Southern Cricket Frog - Acris gryllus, and Pine Woods Treefrog - Dryophytes femoralis). The Gopher frog was present in all four ponds on both sampling dates. Lithobates sphenocephalus was present in Sunset Pond in January and all four ponds in March. These results may contribute to a better understanding of amphibian phenology in isolated ephemeral wetlands of the longleaf pine ecosystem.
Fungi communities in environmental samples were analyzed by microbial DNA extraction and next generation sequencing of ITS sequences. Compost showed a lower fungi diversity responding to the selective pressure of high temperature by limiting the number of fungi adapted to high temperatures compared to forest and garden soils. The compost sample showed a dominance of Ascomycota sequences at the phylum level with Thermomyces and Myceliophthora accounting for more than 94% of the genera detected. The forest soil sample showed higher fungi diversity than garden soil and compost with a predominant community comprised of Basidiomycota at the phylum level and Cortinarius, Piloderma, and Cenococcum at the genus level. However, the garden soil was mostly comprised of unknown fungi at both taxonomical levels. When identification was possible, fungi in garden soil were mostly related to the genera Solheimia, Phialophora, and Lecophagus. Saprophytic fungi were most abundant in compost and garden soil while ectomycorrhizal genera were dominant in forest soil. Beta diversity and Jaccard similarity analyses between habitats showed the fungi community composition was significantly different. Next generation sequencing of ITS sequences provided a better resolution and sensitivity to understand the diversity and community structure of fungi in soils and compost. The presence of large numbers of unclassified ITS sequences demonstrated the need to optimize molecular and cultivation-based methods to recover and identify the tremendous diversity of fungi communities in soils leading to a better understanding of their ecological function in the environment.
Perfluorooctanesulfonic acid (PFOS), a persistent environmental contaminant, remains detectable in U.S. drinking water and oral exposure to PFOS may cause dysbiosis, which is implicated in the pathology of many inflammatory diseases. The goal of this proof-of-concept study was to investigate the effects of subchronic oral PFOS exposure on the composition of the gut microbiota. Adult male and female Sprague-Dawley rats were exposed to PFOS via drinking water at concentrations of 0.5 or 5.0 µg/mL or tap water (naïve) for 28 days. Fecal samples were collected on days 0, 14, and 28, pooled, and analyzed by 16S rRNA next generation sequencing. PFOS exposure resulted in sex- and dose-dependent temporal effects on body weight, food consumption, and water consumption with more pronounced changes observed in males. Community dysbiosis, indicated by altered Firmicutes to Bacteroidetes ratios and alpha diversity, was also more pronounced in males. Weighted UniFrac β-diversity analysis revealed clustering among females exposed to 5.0 µg/mL PFOS and naïve conditions. These findings provide evidence that oral PFOS exposure is associated with mild dysbiosis, particularly in males, which may increase their risk for digestive system diseases and support the notion that females have a mechanism to confer protection against PFOS-induced toxicity.
Every year, plants are exposed to increasingly severe environmental stresses. To survive these constant stressors, plants make metabolic tradeoffs to minimize the damage to their subcellular structures. Highly conserved enzymes such as the Cytochrome P450 (CYP) enzyme family are of particular interest in untangling the stress response displayed by a wide variety of plants, because they catalyze a diverse array of biochemical changes. The CYP72A subfamily is involved in a variety of biochemical responses that may include reacting to external stresses. For example, CYP72A9 is a 13-hydroxylase involved in maintaining seed dormancy. This enzyme modulates gibberellins (GAs), which are crucial to plant growth and development. The gene for CYP72A9 is also induced by various abiotic stresses, and may play a role in the metabolic growth-defense tradeoff in plants. Our work tests the hypothesis that CYP72A9 acts as a 13-hydroxylase in response to osmotic stress. We evaluate this hypothesis by measuring the abundance of several GAs when cyp72a9 mutant plants and wild type plants are exposed to mannitol to induce osmotic stress. We find that in stressed conditions the precursors closer to GA4 on the pathway are in very low abundance in wild type, whereas they remain quite high in cyp72a9 mutant plants, supporting the hypothesis that CYP72A9 is critical in the modulation of gibberellic acid.
