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The obligate marine actinobacterial genus Salinispora has become a model organism for natural product discovery, yet little is known about the ecological functions of the compounds produced by this taxon. The aims of this study were to assess the effects of live cultures and culture extracts from two Salinispora species on invertebrate predators. In choice-based feeding experiments using the bacterivorous nematode Caenorhabditis elegans, live cultures of both Salinispora species were less preferred than Escherichia coli. When given a choice between the two species, C. elegans preferred S. areniolca over S. tropica. Culture extracts from S. tropica deterred C. elegans, while those from S. arenicola did not, suggesting that compounds produced by S. tropica account for the feeding deterrence. Bioactivity-guided isolation linked compounds in the lomaiviticin series to the deterrent activity. Additional assays using the marine polychaete Ophryotrocha siberti and marine nematodes further support the deterrent activity of S. tropica against potential predators. These results provide evidence that Salinispora natural products function as a defense against predation and that the strategies of predation defense differ between closely related species. IMPORTANCE Bacteria inhabiting marine sediments are subject to predation by bacterivorous eukaryotes. Here, we test the hypothesis that sediment-derived bacteria in the genus Salinispora produce biologically active natural products that function as a defense against predation. The results reveal that cultures and culture extracts of S. tropica deter feeding by Caenorhabditis elegans and negatively affect the habitat preference of a marine annelid (Ophryotrocha siberti). These activities were linked to the lomaiviticins, a series of cytotoxic compounds produced by S. tropica. Microbial natural products that function as a defense against predation represent a poorly understood trait that can influence community structure in marine sediments.

Thousands of natural products have been identified from cultured microorganisms, yet evidence of their production in the environment has proven elusive. Technological advances in mass spectrometry, combined with public databases, now make it possible to address this disparity by detecting compounds directly from environmental samples. Here, we used adsorbent resins, tandem mass spectrometry, and next-generation sequencing to assess the metabolome of marine sediments and its relationship to bacterial community structure. We identified natural products previously reported from cultured bacteria, providing evidence they are produced in situ, and compounds of anthropogenic origin, suggesting this approach can be used as an indicator of environmental impact. The bacterial metabolite staurosporine was quantified and shown to reach physiologically relevant concentrations, indicating that it may influence sediment community structure. Staurosporine concentrations were correlated with the relative abundance of the staurosporine-producing bacterial genus Salinispora and production confirmed in strains cultured from the same location, providing a link between compound and candidate producer. Metagenomic analyses revealed numerous biosynthetic gene clusters related to indolocarbazole biosynthesis, providing evidence for noncanonical sources of staurosporine and a path forward to assess the relationships between natural products and the organisms that produce them. Untargeted environmental metabolomics circumvents the need for laboratory cultivation and represents a promising approach to understanding the functional roles of natural products in shaping microbial community structure in marine sediments.IMPORTANCE Natural products are readily isolated from cultured bacteria and exploited for useful purposes, including drug discovery. However, these compounds are rarely detected in the environments from which the bacteria are obtained, thus limiting our understanding of their ecological significance. Here, we used environmental metabolomics to directly assess chemical diversity in marine sediments. We identified numerous metabolites and, in one case, isolated strains of bacteria capable of producing one of the compounds detected. Coupling environmental metabolomics with community and metagenomic analyses provides opportunities to link compounds and producers and begin to assess the complex interactions mediated by specialized metabolites in marine sediments.

Bacterial natural products remain an important source of new medicines. DNA sequencing has revealed that a majority of natural product biosynthetic gene clusters (BGCs) maintained in bacterial genomes have yet to be linked to the small molecules whose biosynthesis they encode. Efforts to discover the products of these orphan BGCs are driving the development of genome mining techniques based on the premise that many are transcriptionally silent during normal laboratory cultivation. Here, we employ comparative transcriptomics to assess BGC expression among four closely related strains of marine bacteria belonging to the genus Salinispora The results reveal that slightly more than half of the BGCs are expressed at levels that should facilitate product detection. By comparing the expression profiles of similar gene clusters in different strains, we identified regulatory genes whose inactivation appears linked to cluster silencing. The significance of these subtle differences between expressed and silent BGCs could not have been predicted a priori and was only revealed by comparative transcriptomics. Evidence for the conservation of silent clusters among a larger number of strains for which genome sequences are available suggests they may be under different regulatory control from the expressed forms or that silencing may represent an underappreciated mechanism of gene cluster evolution. Coupling gene expression and metabolomics data established a bioinformatic link between the salinipostins and their associated BGC, while genetic manipulation established the genetic basis for this series of compounds, which were previously unknown from Salinispora pacifica.

Genome sequencing and the application of omic techniques are driving many important advances in the field of microbial natural products research. Despite these gains, there remain aspects of the natural product discovery pipeline where our knowledge remains poor. These include the extent to which biosynthetic gene clusters are transcriptionally active in native microbes, the temporal dynamics of transcription, translation, and natural product assembly, as well as the relationships between small molecule production and detection. Here we touch on a number of these concepts in the context of continuing efforts to unlock the natural product potential revealed in genome sequence data and discuss nomenclatural issues that warrant consideration as the field moves forward.

The cars we drive, the homes we live in, the restaurants we visit, and the laboratories and offices we work in are all a part of the modern human habitat. Remarkably, little is known about the diversity of chemicals present in these environments and to what degree molecules from our bodies influence the built environment that surrounds us and vice versa. We therefore set out to visualize the chemical diversity of five built human habitats together with their occupants, to provide a snapshot of the various molecules to which humans are exposed on a daily basis. The molecular inventory was obtained through untargeted liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis of samples from each human habitat and from the people that occupy those habitats. Mapping MS-derived data onto 3D models of the environments showed that frequently touched surfaces, such as handles (e.g., door, bicycle), resemble the molecular fingerprint of the human skin more closely than other surfaces that are less frequently in direct contact with humans (e.g., wall, bicycle frame). Approximately 50% of the MS/MS spectra detected were shared between people and the environment. Personal care products, plasticizers, cleaning supplies, food, food additives, and even medications that were found to be a part of the human habitat. The annotations indicate that significant transfer of chemicals takes place between us and our built environment. The workflows applied here will lay the foundation for future studies of molecular distributions in medical, forensic, architectural, space exploration, and environmental applications.

The very first words of the Bill of Rights mark religion as constitutionally distinctive. Congress may not enact laws respecting an establishment of religion--in particular, acts of worship, religious instruction, or proselytizing. A pluralist, liberal democracy requires separation of civil government from these distinctively religious activities. From the middle of the twentieth century until Justice O'Connor's retirement in 2005, the Supreme Court energetically animated that principle of distinctiveness. In a series of decisions in the last decade, however, the Court has upended its longstanding approach to what is distinctive about religion in constitutional law. Notably, this process of change has unfolded with little engagement with, and occasional disdain for, the history and reasoning that underlay once-settled principles. The Court's aggressive undoing of Establishment Clause concerns has been accomplished in large part by dramatically expanding free exercise interests. In this Essay, we analyze these developments. Part I provides a conceptual overview of the idea that certain aspects of religion are constitutionally distinctive. Part II tracks the three major areas of Establishment Clause adjudication in which distinctiveness norms have withered. Part II.A focuses on government financial support of religious entities, with particular emphasis on the recent trilogy, concluding in Carson v. Makin, about state discretion in such matters. Part II.B turns to the collapsing law about state sponsorship of religious exercises and displays. Part II.C confronts the stunning decision in Kennedy v. Bremerton School District, which threatens a sixty-year-old enterprise of prohibiting official prayer in the public schools. In all three contexts, nothing is left except concerns about coercion and nondiscrimination, neither of which depends on the Establishment Clause. Part III turns briefly to the newly declared supremacy of the Free Exercise Clause. We show how a free exercise-based conception of religious distinctiveness generates significant advantages for religious individuals (including staff in public schools) and institutions while simultaneously insulating them from state control. Government, once subject to a distinctive limitation on promoting or sponsoring religion, now must afford religion distinctive privileges. [ABSTRACT FROM AUTHOR]

Background: Low‐risk papillary thyroid carcinoma (LR‐PTC) can be managed by immediate surgery (IS) or active surveillance (AS). We compare the psychological impact of these treatments on patients with LR‐PTC. Methods: Psychological data were collected over 1 year, with assessments at the time of treatment decision (T1), at 6 months (T2) and 12 months (T3) follow‐up. Assessments included 13 validated psychological tools. Results: Of 27 enrolled patients, 20 chose AS and 7 chose IS. The average times to T2 and T3 were 5.7 and 11.3 months, respectively. For both groups, Impact of Events Scale scores significantly decreased (p = 0.001) at T2, and depressive/anxiety symptoms remained low. Conclusions: This study demonstrates the feasibility of assessing psychological outcomes among patients treated for LR‐PTC. Further studies are needed to evaluate the impact of AS versus IS on quality of life and changes that patients experience over longer time periods following their treatment decision. [ABSTRACT FROM AUTHOR]