Premise of the studyThe Climate Reconstruction Analysis using Coexistence Likelihood Estimation (CRACLE) method for the estimation of climate from vegetation is a robust set of modeling tools for estimating climate and paleoclimate that makes use of large repositories of biodiversity data and open-access R software.MethodsHere we implement a new R library for the estimation of climate from vegetation. The ‘cRacle’ library implements functions for data access, aggregation, and models to estimate climate from plant community composition. ‘cRacle’ is modular and features many best-practice features.ResultsPerformance tests using modern vegetation survey data from North and South America shows that CRACLE outperforms alternative methods. CRACLE estimates of mean annual temperature (MAT) are usually within 1°C of the actual when optimal model parameters are used. Generalized Boosted Regression (GBR) model correction is also shown here to improve on CRACLE models by reducing bias.DiscussionCRACLE provides accurate estimates of climate from modern plant communities. Non-parametric CRACLE modeling coupled to GBR model correction produces the most accurate results to date. The ‘cRacle’ R library streamlines the estimation of climate from plant community data, and will make this modeling more accessible to a wider range of users.

We report the complete genome sequence of Clostridium cadaveris IFB3C5, a strain isolated from the resected tumor of a treatment naive colorectal cancer patient. This genome is comprised of a singular chromosome of approximately 3.63 Mbp in length, contains two plasmids, and has an overall mean GC content of 31.7%.

We report the complete genome sequence of Morganella morganii CTX51T, a strain isolated from the resected tumor of a patient with cecal colorectal adenocarcinoma of the cecum. The genome comprises a circular chromosome of 4.19 Mbp, with an overall GC content of 50.4% and one circular plasmid of 8.48 kbp.

Cancerous tissue is a largely unexplored microbial niche that provides a unique environment for the colonization and growth of specific bacterial communities, and with it, the opportunity to identify novel bacterial species. Here, we report distinct features of a novel Fusobacterium species, F. sphaericum sp. nov. (Fs), isolated from primary colon adenocarcinoma tissue. We acquire the complete, closed genome of this organism and phylogenetically confirm its classification into the Fusobacterium genus. Phenotypic and genomic analysis of Fs reveal that this novel organism is of coccoid shape, rare for Fusobacterium members, and has species-distinct gene content. Fs displays a metabolic profile and antibiotic resistance repertoire consistent with other Fusobacterium species. In vitro, Fs has adherent and immunomodulatory capabilities, as it intimately associates with human colon cancer epithelial cells and promotes IL-8 secretion. Analysis of the prevalence and abundance of Fs in ~1,750 human metagenomic samples shows that it is a moderately prevalent member of the human oral cavity and stool. Intriguingly, analysis of ~1,270 specimens from patients with colorectal cancer demonstrate that Fs is significantly enriched in colonic and tumor tissue as compared to mucosa or feces. Our study sheds light on a novel bacterial species that is prevalent within the human intestinal microbiota and whose role in human health and disease requires further investigation.

Fusobacterium nucleatum is among the most prevalent and dominant bacterial species in colorectal cancer (CRC) tumor tissue, and growing evidence supports its role in cancer progression and poorer patient prognosis. Here we perform a small molecule inhibitor screen of 1,846 bioactive compounds against a CRC isolate of F. nucleatum and find that 15% of inhibitors are antineoplastic agents including fluoropyrimidines. Validation of these findings reveal that 5-fluorouracil (5-FU), the first-line chemotherapeutic used to treat CRC worldwide, is a potent inhibitor of F. nucleatum CRC isolates at concentrations found in serum of CRC patients treated with 5-FU. We also identify members of the intratumoral microbiota that are resistant to 5-FU, including Escherichia coli. Further, CRC E. coli isolates can modify 5-FU and relieve 5-FU toxicity towards otherwise-sensitive F. nucleatum and human CRC epithelial cells. Lastly, we demonstrate that ex-vivo CRC tumor microbiota from patients undergo different levels of community disruption after 5-FU exposure and have the potential to deplete 5-FU levels, thereby reducing local drug efficacy. Together, these observations argue for further investigation into the role that the CRC intratumoral microbiota plays in patient response to chemotherapy.