Biosynthesis of Haloterpenoids in Red Algae via Microbial-like Type I Terpene Synthases.

Red algae or seaweeds produce highly distinctive halogenated terpenoid compounds, including the pentabromochlorinated monoterpene halomon that was once heralded as a promising anticancer agent. The first dedicated step in the biosynthesis of these natural product molecules is expected to be catalyzed by terpene synthase (TS) enzymes. Recent work has demonstrated an emerging class of type I TSs in red algal terpene biosynthesis. However, only one such enzyme from a notoriously haloterpenoid-producing red alga (Laurencia pacifica) has been functionally characterized and the product structure is not related to halogenated terpenoids. Herein, we report 10 new type I TSs from the red algae Portieria hornemannii, Plocamium pacificum, L. pacifica, and Laurencia subopposita that produce a diversity of halogenated mono- and sesquiterpenes. We used a combination of genome sequencing, terpenoid metabolomics, in vitro biochemistry, and bioinformatics to establish red algal TSs in all four species, including those associated with the selective production of key halogenated terpene precursors myrcene, trans-ß-ocimene, and germacrene D-4-ol. These results expand on a small but growing number of characterized red algal TSs and offer insight into the biosynthesis of iconic halogenated algal compounds that are not without precedence elsewhere in biology.

Generating high-quality plant and fish reference genomes from field-collected specimens by optimizing preservation.

Sample preservation often impedes efforts to generate high-quality reference genomes or pangenomes for Earth's more than 2 million plant and animal species due to nucleotide degradation. Here we compare the impacts of storage methods including solution type, temperature, and time on DNA quality and Oxford Nanopore long-read sequencing quality in 9 fish and 4 plant species. We show 95% ethanol largely protects against degradation for fish blood (22 °C, ≤6 weeks) and plant tissue (4 °C, ≤3 weeks). From this furthest storage timepoint, we assemble high-quality reference genomes of 3 fish and 2 plant species with contiguity (contig N50) and completeness (BUSCO) that achieve the Vertebrate Genome Project benchmarking standards. For epigenetic applications, we also report methylation frequency compared to liquid nitrogen control. The results presented here remove the necessity for cryogenic storage in many long read applications and provide a framework for future studies focused on sampling in remote locations, which may represent a large portion of the future sequencing of novel organisms.

Scalable Biosynthesis of the Seaweed Neurochemical, Kainic Acid.

Kainic acid, the flagship member of the kainoid family of natural neurochemicals, is a widely used neuropharmacological agent that helped unravel the key role of ionotropic glutamate receptors, including the kainate receptor, in the central nervous system. Worldwide shortages of this seaweed natural product in the year 2000 prompted numerous chemical syntheses, including scalable preparations with as few as six-steps. Herein we report the discovery and characterization of the concise two-enzyme biosynthetic pathway to kainic acid from l-glutamic acid and dimethylallyl pyrophosphate in red macroalgae and show that the biosynthetic genes are co-clustered in genomes of Digenea simplex and Palmaria palmata. Moreover, we applied a key biosynthetic α-ketoglutarate-dependent dioxygenase enzyme in a biotransformation methodology to efficiently construct kainic acid on the gram scale. This study establishes both the feasibility of mining seaweed genomes for their biotechnological prowess.

Treating functional impairment of autism with selective serotonin-reuptake inhibitors.

OBJECTIVE: To review literature describing use of selective serotonin-reuptake inhibitors (SSRIs) in the management of functional impairments associated with autistic disorder. DATA SOURCES: EMBASE (1980-3rd quarter of 2003), International Pharmaceutical Abstracts (1970-August 2003), and MEDLINE (1966-August 2003) were searched. Search terms included autism, autistic disorder, citalopram, fluoxetine, fluvoxamine, paroxetine, selective serotonin-reuptake inhibitors, and sertraline. DATA SYNTHESIS: Studies and case reports evaluating treatment outcomes associated with the use of SSRIs in managing impairments of autism were reviewed. Multiple SSRI dosing ranges were evaluated in autistic patients of different ages with various functional impairments. No specific SSRI or dose range has been shown to improve a specific autistic symptom although some patients have demonstrated improvements. CONCLUSIONS: Benefits with SSRIs in treating functional impairments in autism have been observed. Response to therapy and adverse effects are individualized. Current evidence does not support selection of one SSRI over another for any impairment associated with autism.