Climate change and land‐use change are leading drivers of biodiversity decline, affecting demographic parameters that are important for population persistence. For example, scientists have speculated for decades that climate change may skew adult sex ratios in taxa that express temperature‐dependent sex determination (TSD), but limited evidence exists that this phenomenon is occurring in natural settings. For species that are vulnerable to anthropogenic land‐use practices, differential mortality among sexes may also skew sex ratios. We sampled the spotted turtle (Clemmys guttata), a freshwater species with TSD, across a large portion of its geographic range (Florida to Maine), to assess the environmental factors influencing adult sex ratios. We present evidence that suggests recent climate change has potentially skewed the adult sex ratio of spotted turtles, with samples following a pattern of increased proportions of females concomitant with warming trends, but only within the warmer areas sampled. At intermediate temperatures, there was no relationship with climate, while in the cooler areas we found the opposite pattern, with samples becoming more male biased with increasing temperatures. These patterns might be explained in part by variation in relative adaptive capacity via phenotypic plasticity in nest site selection. Our findings also suggest that spotted turtles have a context‐dependent and multi‐scale relationship with land use. We observed a negative relationship between male proportion and the amount of crop cover (within 300 m) when wetlands were less spatially aggregated. However, when wetlands were aggregated, sex ratios remained consistent. This pattern may reflect sex‐specific patterns in movement that render males more vulnerable to mortality from agricultural machinery and other threats. Our findings highlight the complexity of species' responses to both climate change and land use, and emphasize the role that landscape structure can play in shaping wildlife population demographics.
e22548 Background: Clinical responses in patients with soft tissue sarcoma administered immune checkpoint inhibitors have been infrequent. Little is known regarding the immune microenvironment in soft tissue sarcoma that leads to a lack of effective responses with immune therapies. Whilst several studies have shown T cell infiltration in sarcomas, these tumors do not respond to immunotherapies. Macrophages are important regulators of immune responses in the tumor microenvironment. Studies in mouse models indicate that macrophages regulate immune checkpoint inhibitor response. With the overall goal of developing more effective combination immunotherapies for sarcoma, we examined tumor associated macrophages in patients with soft tissue sarcoma administered neoadjuvant chemotherapy. Interactions between macrophage infiltration, tumor immunogenicity and overall survival were also assessed using publicly available RNAseq and exome mutation data. Methods: Immunohistochemistry was performed on formalin fixed soft tissue sarcoma tissue. Tissues from 20 patients with soft tissue sarcoma pre and post neo-adjuvant chemotherapy were included. TAMs were detected by CD68; M2 subtype were detected by CD163. CD4, CD8, and CD25 T cells were also examined. The density of CD68+ TAMs, CD163+ TAMs and the ratio of CD163+ TAMs / CD68+ TAMs were calculated and their correlation with survival was also made. Publicly available RNAseq and exome mutation data were assembled from The Cancer Genome Atlas (TCGA) sarcoma cohort (n = 259). For each tumor, a relative measure of abundance of tumor-infiltrating macrophages was estimated using gene expression. Tumor mutational burden (TMB), expressed as the rate of non- synonymous mutations per megabase of sequenced DNA, was used as a measure of tumor immunogenicity. Interactions between macrophage infiltration, tumor immunogenicity and overall survival were assessed by Cox regression and Kaplan-Meier analysis. Categorical relationships involving clinical, immunologic, and genomic features of the tumor immune subclasses were compared. Results: Specific alteration in the density of CD68+ TAMs, CD163+ TAMs, and the CD163 / CD68 ratio were observed in patients with soft tissue sarcoma responding to neoadjuvant chemotherapy. Categorical relationships involving macrophage infiltration, TMB, and survival were also observed. Conclusions: These study support the targeting of tumor associated macrophages in patients with soft tissue sarcoma and suggest that changes in TAMs may be achievable using neoadjuvant chemotherapy.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.