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Biology subjects

Sformo, T. L.

Publications and source records attributed to Sformo, T. L..

2 recordsLinked to original sources

Latitudinal gradients in predation persist in urban environments

Urbanization can profoundly disrupt local ecology. But while urban areas now stretch across latitudes, little is known about urbanizations effects on macroecological patterns. We used standardized experiments to test whether urbanization disrupts latitudinal gradients in seed predation, a macroecological pattern that shapes community assembly and diversity. Using >56,000 seeds, we compared predation in urbanized and natural areas across 14,000 km of latitude, spanning the Americas. Predation increased 5-fold from high latitudes to the tropics, and latitudinal gradients in predation persisted in urban areas despite significant habitat modification. Urbanization reduced predation by vertebrates, but not invertebrates, and seemed to increase ant predation specifically. Our results show that macroecological patterns in predation intensity can persist in urbanized environments, even as urbanization alters the relative importance of predators. One-Sentence SummaryAcross 56,000 seeds and 112{degrees} of latitude, latitudinal gradients in seed predation are equally strong in natural vs. urban areas

ecology↗

DNA repair and anti-cancer mechanisms in the longest-living mammal: the bowhead whale

At over 200 years, the maximum lifespan of the bowhead whale exceeds that of all other mammals. The bowhead is also the second-largest animal on Earth, reaching over 80,000 kg1. Despite its very large number of cells and long lifespan, the bowhead is not highly cancer-prone, an incongruity termed Petos Paradox2. This phenomenon has been explained by the evolution of additional tumor suppressor genes in other larger animals, supported by research on elephants demonstrating expansion of the p53 gene3-5. Here we show that bowhead whale fibroblasts undergo oncogenic transformation after disruption of fewer tumor suppressors than required for human fibroblasts. However, analysis of DNA repair revealed that bowhead cells repair double strand breaks (DSBs) and mismatches with uniquely high efficiency and accuracy compared to other mammals. The protein CIRBP, implicated in protection from genotoxic stress, was present in very high abundance in the bowhead whale relative to other mammals. We show that CIRBP and its downstream protein RPA2, also present at high levels in bowhead cells, increase the efficiency and fidelity of DNA repair in human cells. These results indicate that rather than possessing additional tumor suppressor genes as barriers to oncogenesis, the bowhead whale relies on more accurate and efficient DNA repair to preserve genome integrity. This strategy which does not eliminate damaged cells but repairs them may be critical for the long and cancer-free lifespan of the bowhead whale.

cancer biology↗