Alkaloids include some of the most impactful molecules used in science and medicine. While plant alkaloids are well explored, much less is known about the diverse bioactive alkaloids from the animal kingdom. To solve this problem, we developed a computational method to discover genes that are bundled in chromosomal regions, enabling agnostic discovery of noncanonical biosynthetic gene clusters (BGCs) without prior knowledge of what enzymes might be involved. The method was applied to marine sponges that produce oroidin and related pyrrole-imidazole alkaloids, uncovering 36 BGCs in oroidin-producing sponges, only one of which (oro) was found in all species. Many of these clusters defy current BGC dogma, leading us to suggest the name "bundles" for this phenomenon. Five oro proteins were validated in biochemical assays. oro consists of orthologs of common, animal-specific primary metabolic genes that have been collected in one chromosomal region and repurposed for alkaloid biosynthesis. This provides a roadmap to accelerate the development of oroidins and the countless other unique natural products found in the animal kingdom.

Lipopeptide natural products are essential agents against multidrug-resistant bacteria, but their clinical utility is often constrained by toxicity and resistance. Here, we compare the mechanisms of action of two superficially similar lipopeptide antibiotics: colistin, a last-line treatment for Gram-negative infections, and turnercyclamycins, a new class active against certain colistin-resistant strains. Both antibiotics require lipopolysaccharide (LPS) biosynthesis, even when LPS transport to the outer membrane (OM) is impaired. Colistin rapidly disrupts both the OM and the cytoplasmic membrane (CM), causing swift bacterial death. Turnercyclamycins, by contrast, act independently of the CM, with delayed OM disruption. Unlike colistin, which binds LPS directly to damage membranes, turnercyclamycins show no measurable LPS binding by calorimetry. Instead, their activity is modulated by different phospholipids, as confirmed by phospholipidomic profiling on whole cells, which identifies alterations in bacterial lipid biosynthesis and membrane homeostasis. These findings support a mechanistically distinct mode of action for turnercyclamycins, which we propose to correlate with their different pharmacological properties and potential therapeutic applications. Our results highlight how subtle structural differences between lipopeptides can lead to major functional divergence, offering a framework for the rational design of next-generation antibiotics with improved safety and efficacy profiles.

With the ongoing antibiotic drug resistance crisis, new molecules with new mechanisms of action are essential. Here, we characterized quorum sensing-regulated butuanimides from symbiotic γ-proteobacteria, Teredinibacter sp. 2052S, which kill Gram-positive bacterial and human cells with micromolar and submicromolar potencies, respectively. Butuanimides share a peptide-imide moiety with andrimid-class antibiotics that target bacterial acetyl-CoA carboxylase (ACC), the rate-limiting step in fatty acid biosynthesis. Similarly, site-directed mutagenesis in Acinetobacter baylyi identified the ACC carboxyl transferase (CT) subunit as responsible for butuanimide antibacterial activity. The andrimid-like peptide-imide moiety is attached to a longer, halogenated polyene chain that initiates with an unusual starter unit likely derived from phenylalanine. The resulting epoxyquinone is unstable in solution over a period of hours to days, enabling redox control of antibiotic action. Comparison of the hybrid polyketide synthase-nonribosomal peptide synthetase (PKS-NRPS) biosynthetic gene clusters of butuanimides and andrimid suggests the repurposing of a key phenylalanine-derived motif. The butuanimide structures link the thailandamide- and andrimid-class ACC inhibitors, which should aid ongoing efforts in the development of ACC inhibitors to treat multidrug-resistant infections.

Soft corals are prolific producers of terpenoids, such as pseudopterosins. The exact biosynthetic pathway of these anti-inflammatory diterpene glycosides has eluded the scientific community for decades. Using a forward genetic approach, we have identified, cloned, and expressed the key genes involved in pseudopterosin biosynthesis. We characterized a unique class of multifunctional cytochrome P450 enzymes that catalyze a cascade reaction that produces a nearly mature natural product using a single enzyme. This clarifies the previously proposed biosynthetic pathways to pseudopterosin A and its relatives. The mechanism of the oxidative cascade was probed using in vivo feeding studies in Saccharomyces cerevisiae expressing heterologous coral genes. The cascade produces the pseudopterosin aglycone 7,8-dihydroxyerogorgiaene via elisabethatrienol and its epimer, starting from elisabethatriene. This discovery demonstrates the potential to produce this valuable class of natural products using fermentation.

The borate-binding polyketide macrolide natural products are a long-known family of bacterial antibiotics and antiparasitic agents. Among these, tartrolon E is highly potent and selective in killing eukaryotic parasites while sparing mammalian cells. However, it has been challenging to obtain, fully chemically define, and formulate the tartrolons. Here, we describe a streamlined route to obtain pure tartrolon E as a highly crystalline material. The method yielded crystals of tartrolon E, the analysis of which revealed the stable chelation of a sodium counterion. Using this chemically defined material, additional experiments permitted quantitative cation exchange with alkali-metal cations, suggesting a relative binding affinity of Li+ > Na+ > K+. In cases where complex mixtures of boronated/deboronated tartrolons are obtained, we developed methods to cleanly deboronate tartrolon E, yielding tartrolon D, and to reintroduce the boron atom back to the complex. Overall, we demonstrate practical methods to deliver chemically defined complexes of tartrolon E, which will facilitate further study of the intriguing biological activities of this potently bioactive macrolide family and enable the preclinical development of these important antiparasitic and antibiotic agents.

Teredinibactins are β-resorcyclic thiazoline dipeptides synthesized by Teredinibacter turnerae T7901, a bacterial symbiont of shipworms in the sea. Through feeding studies, we show that the thiazoline moiety is made from glutathione and its metabolites in a noncanonical pathway, for which we suggest the name "glutazoline". Mimicking the biosynthetic reaction, we synthesized both natural and unnatural teredinibactins. The results expand the scope of biological and chemical approaches to aromatic azoline conjugates.

Covering 2010 to 2025Sponges are benthic, sessile invertebrate metazoans that are some of the most prolific sources of natural products in the marine environment. Sponge-derived natural products are often endowed with favorable pharmaceutical bioactivities, and paired with their structural complexity, have long served as title compounds for chemical syntheses. Sponges are holobionts, in that the sponge host is associated with symbiotic and commensal microbiome. Natural products isolated from sponges can be produced by the sponge host, or the associated microbiome. Recent genomic studies have shed light on the sponge eukaryotic host as the true producer of several classes of sponge-derived peptidic natural products. In this review spanning years 2010-2025, we describe peptidic natural products isolated from the sponge hosts and the associated microbiome, detail their biosynthetic processes where known, and offer forward looking insights into future innovation in discovery and biosynthesis of peptidic natural products from marine sponges.

Cone snails (genus Conus Linnaeus, 1758) represent one of the most species-rich lineages of venomous marine snails, producing diverse and highly specialized toxins. While Conus diversity is particularly high in the Indo-Pacific, some regions, such as the archipelago of Palau, remain poorly studied. Here, we combine mitochondrial marker gene sequencing (COI, 12S, and 16S) and venom-gland transcriptomics to investigate the phylogenetic relationships and venom gene diversity of Palauan Conus species. We sampled 27 species, recovering mitochondrial sequences for 34–41 individuals per gene. Maximum-likelihood phylogenetic analysis revealed that most individuals group with known species, although several lineages show notable divergence from reference sequences. We additionally sequenced venom gland transcriptomes from 21 individuals representing 14 species, including three species for which no previous venom data exist. Comparative analysis showed largely consistent expression patterns at the superfamily level within species collected from different biogeographical regions, supporting conserved venom gene expression profiles. These results contribute foundational data for future studies of Conus evolution, biogeography, and toxin diversification in an underexplored biodiversity hotspot. ### Competing Interest Statement The authors have declared no competing interest. University of Utah, https://ror.org/03r0ha626

Symbiotic bacteria produce defensive compounds found in their eukaryotic hosts, such as marine sponges. How these symbioses are formed in each sponge, their biodiversity, and their ecological roles in nature are open challenges that remain to be addressed. Here, we describe a candidate bacterial genus, Jaspinella sp., that harbors biosynthetic genes for the potent natural product toxin jaspamide (jasplakinolide) in the microbiomes of two geographically and taxonomically diverse sponge species, Jaspis (=Dorypleres) splendens and Dictyonella sp. The jas gene cluster in Jaspinella matches the expectation for jaspamide biosynthesis, including a nonribosomal peptide synthetase (NRPS) region homologous to the characterized chondramide cluster that produces a related compound in cultivated myxobacteria and a polyketide synthase (PKS) region that evolved convergently. Jaspinella is a member of Tectomicrobia, which consists of uncultivated bacteria including many well-known defensive sponge symbionts. However, Jaspinella is from a group previously associated only with soil and sediment bacteria, expanding the phylogenetic diversity of Tectomicrobia, the defensive symbioses in marine sponges, and knowledge of defensive compound evolution in nature.

Bryostatin 1 is a protein kinase C (PKC α, β, δ) activator with anti-inflammatory effects. We hypothesized that bryostatins 1 and 3 could modulate transient receptor potential (TRP) channels via PKC and alter TRP-mediated proinflammatory signaling in lung epithelial cells challenged with a proinflammatory stimulus, coal fly ash (CFA). Bryostatins 1 and 3 inhibited icilin-induced calcium flux in HEK-293 cells overexpressing full-length human transient receptor potential melastatin-8 (TRPM8) but did not inhibit activation by menthol or the activities of human transient receptor potential ankyrin 1, transient receptor potential vanilloid 1 (TRPV1), TRPV3, or TRPV4; mouse and rat TRPM8 were less sensitive to inhibition. TRPM8 inhibition was transient (<24 hours), PKC-dependent, and involved differential phosphorylation of amino acids T17, S27, S850, and S1040. CFA particles stimulate interleukin-8 (IL8) and C-X-C motif chemokine ligand 1 (CXCL1) expression by human bronchial epithelial cells via activation of truncated TRPM8 (TRPM8-Δ801) and TRPV1. However, bryostatins 1 and 3 altered IL8 and CXCL1 mRNA expression with and without CFA treatment. At 4 hours, the bryostatins also suppressed TRPM8 mRNA and induced TRPV1 mRNA, which reversed at 24 hours. These effects were reversed by pharmacological inhibition of PKC isoforms (α, ζ, ε, or η) but not δ, implying a network comprised of presumably PKCα, TRPM8-Δ801, and TRPV1 that regulates IL8 and CXCL1 expression by airway epithelial cells. Finally, an unexpected interaction between TRPV1 and TRPM8, but not TRPM8-Δ801, was also identified. Specifically, the coexpression of TRPM8 and TRPV1 reduced TRPM8 expression and activity, which was reversed by TRPV1 inhibition, revealing novel mechanisms by which bryostatins and PKC affect TRP channel signaling in lung epithelial and potentially other cell types. SIGNIFICANCE STATEMENT: Bryostatins 1 and 3 selectively and transiently inhibit human TRPM8 activity via protein kinase C-dependent phosphorylation and temporally modify the expression and induction of interleukin-8 and C-X-C motif chemokine ligand 1 in lung epithelial cells by regulating TRPV1 and TRPM8 expression. This regulatory nexus may have therapeutic potential for treating airway inflammation.

Halogenated molecules produced by marine algae are thought to be defensive secondary metabolites. The extraordinarily high concentration of bromoform in the seaweed Asparagopsis—up to 8% dry tissue weight—challenges the exclusivity of this paradigm. In this report, we provide evidence that the mbb1 gene which encodes the bromoform producing halogenase is among the most highly transcribed genes in Asparagopsis tissue, with the resulting Mbb1 protein abundance rivaling that of enzymes involved in photosynthesis and carbon fixation. When the seaweed was stressed with light, transcripts for both mbb1 and for proteins involved in photosynthesis were significantly downregulated. Conversely, heat stress modestly upregulated some photosynthesis genes but had no impact on mbb1. Taken together, these findings allow us to posit that bromoform production is not solely a stress-response or self-defense mechanism for A. taxiformis. Instead, we propose that the halogenase Mbb1 likely fulfils a primary metabolic function in this red alga thusly reconceptualizing halogenation biochemistry and pulling it out of the domain of natural product biosynthesis alone.

The bursatellin-oxazinin family is a series of tyrosine-derived, nitrile-containing marine natural products from gastropod and bivalve molluscs. Although the first analogs were identified and associated with toxicity 40 years ago, their biosynthetic origins were unknown. During an investigation of published mollusc genomes and transcriptomes, we serendipitously identified a putative bursatellin biosynthetic gene cluster (referred hereafter as the bur-ox pathway). Through biochemical characterization of some bur-ox genes, we provide evidence suggesting that bursatellin-type metabolites are produced by molluscs themselves rather than by their microbial symbionts. We show that the reductive domain from a monomodular nonribosomal peptide synthetase (NRPS) protein FmtATR performs a four-electron reduction to produce tyrosinols from tyrosine derivatives. Moreover, an aminocarboxypropyltransferase enzyme, ACT, uses S-adenosylmethionine (SAM) to transform tyrosinols into their phenolic homoserine ethers, which in bursatellin is further modified to the nitrile. Widespread occurrence of bur-ox in molluscs suggests a common biosynthetic origin for bursatellins and oxazinins as well as an important but currently unidentified physiological role for this metabolite family in molluscs inhabiting diverse ecological niches. The presence of bur-ox pathway homologues in culinary bivalves, such as mussels and geoducks, calls into question the potential of oxazinins as toxins. As one of the few NRPS pathways of animal origin to be characterized, bur-ox sheds light on underappreciated chemical and biochemical diversity in animals.

Octocorals are metazoans that prolifically produce terpenoid natural products, rivaling the chemical diversity of plants and microbes. We recently established that these cnidarians uniformly express terpene cyclases and that their encoding genes often reside within putative biosynthetic gene clusters (BGCs). Here we report the discovery and characterization of a widespread gene cluster family for briarane diterpenoid biosynthesis. We sequence five genomes from evolutionarily distinct families of briarane-producing octocorals, revealing a conserved five-gene cluster. Expressing these genes in heterologous hosts, we reconstitute the biosynthesis of cembrene B γ-lactone, an established molecule that contains the lactone structural feature distinctive of briarane diterpenoids. The discovery of the genomic basis of briarane biosynthesis establishes that animals also use gene cluster families to produce specialized metabolites. Furthermore, the presence of BGCs in octocorals proves that the formation and maintenance of BGCs related to specialized metabolite biosynthesis is a more widespread phenomenon than previously realized.

The polyketide synthases (PKSs) in microbes and the cytoplasmic fatty acid synthases in humans (FASs) are related enzymes that have been well studied. As a result, there is a paradigm explaining in general terms how FASs repeatedly use a set of enzymatic domains to produce simple fats, while PKSs use the domains in a much more complex manner to produce pharmaceuticals and other elaborate molecules. However, most animals also have PKSs that do not conform to the rules described in microbes, including a large family of enzymes that bridge fatty acid and polyketide metabolism, the animal FAS-like PKSs (AFPKs). Here, we present the cryoelectron microscopy structures of two AFPKs from sea slugs. While the AFPK resemble mammalian FASs, their chemical products mimic those of PKSs in complexity. How then does the architecture of AFPKs facilitate this structural complexity? Unexpectedly, chemical complexity is controlled not solely by the enzymatic domains but is aided by the dynamics of the acyl carrier protein (ACP), a shuttle that moves intermediates between these domains. We observed interactions between enzyme domains and the linker-ACP domain, which, when manipulated, altered the kinetic properties of the enzyme to change the resulting chemical products. This unveils elaborate mechanisms and enzyme motions underlying lipid and polyketide biochemistry across the domains of life.

Cyanobactin biosynthetic pathways are used in synthetic biology approaches to create large, peptide-based chemical libraries with drug-like features such as N-C macrocyclization and prenylation. It remains challenging to express enzymes from multiple RiPP pathways to rationally produce the desired products. Here, we designed a simple yet robust method aimed to produce and assess multiple enzymes, fusing biosynthetic genes together in a well-expressed, soluble construct that enables production of macrocyclic peptides and selectively appends C5, C10, or C15 isoprenoids to tyrosine side chains. A library was developed and assayed, defining the sequence features necessary for prenylation and providing an overall >40% success rate of using a library with an estimated maximum size of 2.6 million peptide derivatives. This flexible and robust system enables the generation of novel compounds and libraries of such compounds with minimal side products in living organisms.

Cellulosic materials are commonly used in the production of biofuels and other commodity chemicals. Here, we employ a cellulolytic bacterium to produce high-value antibiotics using paper and plant waste materials as primary feedstocks. Teredinibacter turnerae is an intracellular symbiont of shipworms, marine bivalves of the family Teredinidae, where it contributes cellulases and other carbohydrate-active enzymes that help animals digest wood. T. turnerae is also a prolific producer of antibiotic drug leads proposed to be integral to shipworm ecology. In the presence of waste cellulose as the sole carbon source, T. turnerae robustly produced potent antiparasitic and antibiotic agents. This suggests an inexpensive strategy to harness mixed waste materials for the synthesis of high-value compounds, such as pharmaceuticals.

The varied pigments found in animals play both ecological and physiological roles. Virtually all echinoderms contain putative pigment biosynthetic enzymes, the polyketide synthases (PKSs). Among these, crinoids have complex pigments found both today and in ancient fossils. Here, we characterize a key pigment biosynthetic enzyme, CrPKS from the crinoid Anneissia japonica. We show that CrPKS produces 14-carbon aromatic pigment precursors. Despite making a compound previously found in fungi, the crinoid enzyme operates by different biochemical principles, helping to explain the diverse animal PKSs found throughout the metazoan (animal) kingdom. Unlike SpPks1 from sea urchins that had strict starter unit selectivity, CrPKS also incorporated starter units butyryl- or ethylmalonyl-CoA to synthesize a crinoid pigment precursor with a saturated side chain. By performing biochemical experiments, we show how changes in the echinoderm pigment biosynthetic enzymes unveil the vast variety of colors found in animals today.

The alveolar-capillary barrier includes microvascular endothelial and alveolar epithelial cells and their matrices, and its disruption is a critical driver of lung injury during development of acute respiratory distress syndrome. In this review, we provide an overview of the structure and function of the alveolar-capillary barrier during health and highlight several important signaling mechanisms that underlie endothelial and epithelial injury during critical illness, emphasizing areas with potential for development of therapeutic strategies targeting alveolar-capillary leak. We also emphasize the importance of biomarker and preclinical studies in developing novel therapies and highlight important areas warranting future investigation.

Secondary metabolites often function as antipredator defenses, but when bioactive at low concentrations, their off-target effects on other organisms may be overlooked. Candidate “keystone molecules” are proposed to affect community structure and ecosystem functions, generally originating as defenses of primary producers; the broader effects of animal chemistry remain largely unexplored, however. Here, we characterize five previously unreported polyketides (alderenes A to E) biosynthesized by sea slugs reaching exceptional densities (up to 9000 slugs per square meter) in Northern Hemisphere estuaries. Alderenes comprise only 0.1% of slug wet weight, yet rendered live slugs or dead flesh unpalatable to three co-occurring consumers, making a potential food resource unavailable and redirecting energy flow in critical nursery habitat. Alderenes also displaced infauna from the upper sediment of the mudflat but attracted ovipositing snails. By altering communities, such compounds may have unexpected cascading effects on processes ranging from bioturbation to reproduction of species not obviously connected to the producing organisms, warranting greater attention by ecologists.