Successional Age, Not Functional Guild, Predicts Inter-Species Phosphorus Acquisition Strategies in a Lowland, Tropical Forest

Trees capable of di-nitrogen fixation play a critical role in establishing the nitrogen content of early successional soils, yet the responses of this functional guild to nutrient co-limitation and nutrient cycling in tropical ecosystems remain largely unresolved. Notably, fixers in early successional forests grow more rapidly than non-fixers, despite supporting the high energetic costs of fixation. This eccentricity has led some to suggest fixation may provide an adaptive advantage to a fixer’s early development, possibly by assisting fixers in alleviating additional sources of nutrient limitation. We examined the interaction of nitrogen fixation and phosphorus acquisition strategies across a successional soil gradient in a lowland, Panamanian tropical forest. We quantified the extent of mycorrhizal colonization and root phosphatase activity for three species of fixer and three species of non-fixer. Statistical comparisons of relative differences in mycorrhizal colonization and root phosphatase activity among individuals allowed us to elucidate the extent and identity of relationships between phosphorus acquisition strategy, species, successional age, tree size, soil phosphorus content, and functional guild. Significantly, our findings indicate that a tree’s metabolic interest in phosphorus is not influenced by its propensity for di-nitrogen fixation, but rather by the local, macro-nutrient limitations relative to evolving successional soils. This study represents the first observational data set to combine both mycorrhizal and phosphatase data in the context of functional guild and successional age. Thusly, our results have broad implications for the study of nutrient limitation and biogeochemical cycling in tropical ecosystems

Etiologies of Melanoma Development and Prevention Measures: A Review of the Current Evidence

(1) Melanoma is the most aggressive dermatologic malignancy, with an estimated 106,110 new cases to be diagnosed in 2021. The annual incidence rates continue to climb, which underscores the critical importance of improving the methods to prevent this disease. The interventions to assist with melanoma prevention vary and typically include measures such as UV avoidance and the use of protective clothing, sunscreen, and other chemopreventive agents. However, the evidence is mixed surrounding the use of these and other interventions. This review discusses the heritable etiologies underlying melanoma development before delving into the data surrounding the preventive methods highlighted above. (2) A comprehensive literature review was performed to identify the clinical trials, observational studies, and meta-analyses pertinent to melanoma prevention and incidence. Online resources were queried to identify epidemiologic and clinical trial information. (3) Evidence exists to support population-wide screening programs, the proper use of sunscreen, and community-targeted measures in the prevention of melanoma. Clinical evidence for the majority of the proposed preventive chemotherapeutics is presently minimal but continues to evolve. (4) Further study of these chemotherapeutics, as well as improvement of techniques in artificial intelligence and imaging techniques for melanoma screening, is warranted for continued improvement of melanoma prevention