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The study of complex ecosystems requires an understanding of the chemical processes involving molecules from several sources. Some of the molecules present in fungus-growing ants’ symbiotic system originate from plants. Many ant species grow fungus gardens that predigest food as an essential step of the ants’ nutrient uptake. These symbiotic fungus gardens have long been studied and feature a gradient of increasing substrate degradation from top to bottom. To further facilitate the study of fungus gardens and enable the understanding of the predigestion process in more detail than currently known, we applied recent mass spectrometry-based approaches and generated a three-dimensional (3D) molecular map of an Atta texana fungus garden to reveal chemical modifications as plant substrates pass through it. The metabolomics approach presented in this study can be applied to study similar processes in natural environments to compare with lab-maintained ecosystems. IMPORTANCE The study of complex ecosystems requires an understanding of the chemical processes involving molecules from several sources. Some of the molecules present in fungus-growing ants’ symbiotic system originate from plants. To facilitate the study of fungus gardens from a chemical perspective, we provide a molecular map of an Atta texana fungus garden to reveal chemical modifications as plant substrates pass through it. The metabolomics approach presented in this study can be applied to study similar processes in natural environments.

Many ant species grow fungus gardens that predigest food as an essential step of the ants’ nutrient uptake. These symbiotic fungus gardens have long been studied and feature a gradient of increasing substrate degradation from top to bottom. To further facilitate the study of fungus gardens and enable the understanding of the predigestion process in more detail than currently known, we applied recent mass spectrometry-based approaches and generated a three-dimensional (3D) molecular map of an Atta texana fungus garden to reveal chemical modifications as plant substrates pass through it. The metabolomics approach presented in this study can be applied to study similar processes in natural environments to compare with lab-maintained ecosystems. IMPORTANCE The study of complex ecosystems requires an understanding of the chemical processes involving molecules from several sources. Some of the molecules present in fungus-growing ants’ symbiotic system originate from plants. To facilitate the study of fungus gardens from a chemical perspective, we provide a molecular map of an Atta texana fungus garden to reveal chemical modifications as plant substrates pass through it. The metabolomics approach presented in this study can be applied to study similar processes in natural environments.

Fungus-growing ants depend on a fungal mutualist that can fall prey to fungal pathogens. This mutualist is cultivated by these ants in structures called fungus gardens. Ants exhibit weeding behaviors that keep their garden healthy by physically removing compromised pieces. However, how ants detect diseases of their fungus gardens is unknown. Here, we applied the logic of Koch's postulates using environmental fungal community genomic sequencing, fungal isolation, and in vitro infection experiments to establish Trichoderma spp. as pathogens of Trachymyrmex septentrionalis fungus gardens. Our environmental data showed that Trichoderma are the most abundant non-cultivar fungi in wild T. septentrionalis fungus gardens. We further determined that metabolites produced by Trichoderma induce an ant weeding response that mirrors their response to live Trichoderma. Combining ant behavioral experiments with bioactivity-guided fractionation and statistical prioritization of metabolites in Trichoderma extracts demonstrated that T. septentrionalis ants weed in response to peptaibols, a specific class of secondary metabolites known to be produced by Trichoderma fungi. Similar assays conducted using purified peptaibols, including the two new peptaibols trichokindins VIII and IX, suggested that weeding is likely induced by peptaibols as a class rather than by a single peptaibol metabolite. In addition to their presence in laboratory experiments, we detected peptaibols in wild fungus gardens. Our combination of environmental data and in vitro experiments strongly support that peptaibols act as chemical cues of Trichoderma pathogenesis in T. septentrionalis fungus gardens.Competing Interest StatementK.E.K., S.P.P., A.M.C.R., J.R.-C., R.M.S., C.E.E., M.E., M.E.A., J.L.K, and M.J.B declare no competing interest. N.H.O., C.J.P. and H.A.R are members of the Scientific Advisory Board of Clue Genetics, Inc. N.H.O. is also a member of the Scientific Advisory Board of Mycosynthetix, Inc. J.J.J.v.d.H. is a member of the Scientific Advisory Board of NAICONS Srl. P.C.D. is a scientific co-founder and advisor to Ometa and Enveda with prior approval by UC-San Diego and an advisor to Cybele.

Abstract Most animals digest their food within their own bodies, but some do not. Many species of ants grow fungus gardens that pre-digest food as an essential step of the ants’ nutrient uptake. To better understand this digestion process, we generated a 3D molecular map of an Atta texana fungus garden, revealing chemical modifications mediated by the fungus garden as plant material passes through. Competing Interest Statement PCD is a scientific advisor to Sirenas. MW is Founder of Ometa Labs LLC.

We introduce a web-enabled small-molecule mass spectrometry (MS) search engine. To date, no tool can query all the public small-molecule tandem MS data in metabolomics repositories, greatly limiting the utility of these resources in clinical, environmental and natural product applications. Therefore, we introduce a Mass Spectrometry Search Tool (MASST) (https://proteosafe-extensions.ucsd.edu/masst/), that enables the discovery of molecular relationships among accessible public metabolomics and natural product tandem mass spectrometry data (MS/MS). Footnotes * https://proteosafe-extensions.ucsd.edu/masst

The underuse of oral anticoagulation in patients with nonvalvular atrial fibrillation (AF) is a major issue that is not well understood. To understand the lack of anticoagulation by assessing the perceptions of patients with AF who are not receiving anticoagulation and their physician's about the risk of stroke and the benefits and risks of anticoagulation. This cohort study included patients with nonvalvular AF and a CHA2DS2-VASc score of 2 or more (calculated as congestive heart failure, hypertension, age 75 years and older, diabetes, stroke or transient ischemic attack, vascular disease, age 65 to 74 years, and sex category) who were not receiving anticoagulation and were enrolled from 19 sites within the National Cardiovascular Data Registry (NCDR) Practice Innovation and Clinical Excellence Registry (PINNACLE Registry) between January 18, 2017, and May 7, 2018. Data were collected from January 18, 2017, to September 30, 2019, and analyzed from April 2022 to March 2023. Each patient enrolled in the study completed a survey, and their treating physician then conducted a clinical review of their care. Assessment of willingness for anticoagulation treatment and its appropriateness after central review by a panel of 4 cardiologists. Use of anticoagulation at 1 year follow-up was compared vs similar patients at other centers in the PINNACLE Registry. Of the 817 patients enrolled, the median (IQR) age was 76.0 (69.0-83.0) years, 369 (45.2%) were women, and the median (IQR) CHA2DS2-VASc score was 4.0 (3.0-6.0). The top 5 reasons physicians cited for no anticoagulation were low AF burden or successful rhythm control (278 [34.0%]), patient refusal (272 [33.3%]), perceived low risk of stroke (206 [25.2%]), fall risk (175 [21.4%]), and high bleeding risk (167 [20.4%]). After rereview, 221 physicians (27.1%) would reconsider prescribing oral anticoagulation as compared with 311 patients (38.1%), including 67 (24.6%) whose physician cited patient refusal. Of 647 patients (79.2%) adjudicated as appropriate or may be appropriate for anticoagulation, physicians would reconsider anticoagulation for only 177 patients (21.2%), while 527 patients (64.5%) would either agree to starting anticoagulation (311 [38.1%]) or were neutral (216 [27.3%]) to starting anticoagulation. Upon follow-up, 119 patients (14.6%) in the BOAT-AF study were prescribed anticoagulation, as compared with 55 879 of 387 975 similar patients (14.4%) at other centers in the PINNACLE Registry. The findings of this cohort study suggest that patients with AF who are not receiving anticoagulation are more willing to consider anticoagulation than their physicians. These data emphasize the need to revisit any prior decision against anticoagulation in a shared decision-making manner.