A novel nucleic acid linker for multi-gene expression enhances plant and animal synthetic biology.

The production of compact vectors for gene stacking is hindered by a lack of effective linkers. Here, we report that a 26-nt nucleic acid linker, NAL1, from the fungus Glarea lozoyensis and its truncated derivatives could connect two genes as a bicistron, enabling independent translation in a maize protoplast transient expression system and human 293 T cells. The optimized 9-nt NAL10 linker was then used to connect four genes driven by a bidirectional promoter; this combination was successfully used to reconstruct the astaxanthin biosynthesis pathway in transgenic maize. The short and efficient nucleic acid linker NAL10 can be widely used in multi-gene expression and synthetic biology in animals and plants.

Dabigatran-related serious medication errors: an analysis using data from VigiBase.

OBJECTIVE: To analyze the serious medication errors (MEs) on dabigatran, and their related factors, in order to avoid or reduce the occurrence of adverse events. METHODS: Serious MEs related to dabigatran were extracted from the WHO global database of reported potential side effects of medicinal products (VigiBase) by using "Medication errors and other product use errors and issues" High Level Group Term (HLGT) of the international Medical Dictionary for Regulatory Activities (MedDRA). Well-documented reports, vigiGrade completeness score ≥ 0.80, or with an informative narrative were analyzed with a focus on the clinical features of the cases. The PCNE Classification for drug-related problems (DRP) was used to classify medication errors in our analysis of cases. RESULTS: Until January 26, 2020, there were 453 cases with serious MEs related to dabigatran in VigiBase, and 113 were well-documented. Among these, 69 patients (61%) were hospitalized or had prolonged hospitalization, 16 (14%) had life-threatening events, and 12 (11%) died. The MEs occurred in the prescription phase in 77 cases, in administration in 35, and at the dispensing stage in one case. The MEs in prescription were related to a drug selection error in 44 cases (24 concerning contraindications and 20 drug interactions) and to dose error in 33 cases (17 with excessive dose; eight with insufficient frequency; four had an incorrect time; in three, the dose was too low; and in one, too frequent). The MEs in administration were medical-staff-related errors in five cases (three with wrong administration route, one administration omission, and one overdose), patient-related errors in 28 (14 insufficient dose or no administration, seven improper drug storage, four wrong administration method, and three over prescribed dose), and other errors in two (without efficacy monitoring). The dispensing error of a wrong drug strength occurred in a pharmacy. The main adverse events in the 113 patients were haemorrhage in 57 cases (50%) and ischemia in 29 cases (26%). CONCLUSION: Based on the analysis of reports in VigiBase, serious MEs related to dabigatran mainly occurred during prescription and administration. Although the incidence of MEs with clinical consequences in the use of dabigatran cannot be determined, attention should be paid to selection of the appropriate dose to a right patient in the prescription, and to patient compliance and storage in drug administration. The patient harm mainly manifested itself as bleeding or ischemia including fatal outcome in rare patients.

Re-Engineering Fungal Nonribosomal Peptide Synthetases by Module Dissection and Duplicated Thiolation Domains.

Unnatural product (uNP) nonribosomal peptides promise to be a valuable source of pharmacophores for drug discovery. However, the extremely large size and complexity of the nonribosomal peptide synthetase (NRPS) enzymes pose formidable challenges to the production of such uNPs by combinatorial biosynthesis and synthetic biology. Here we report a new NRPS dissection strategy that facilitates the engineering and heterologous production of these NRPSs. This strategy divides NRPSs into "splitting units", each forming an enzyme subunit that contains catalytically independent modules. Functional collaboration between the subunits is then facilitated by artificially duplicating, at the N-terminus of the downstream subunit, the linker - thiolation domain - linker fragment that is resident at the C-terminus of the upstream subunit. Using the suggested split site that follows a conserved motif in the linker connecting the adenylation and the thiolation domains allows cognate or chimeric splitting unit pairs to achieve productivities that match, and in many cases surpass those of hybrid chimeric enzymes, and even those of intact NRPSs, upon production in a heterologous chassis. Our strategy provides facile options for the rational engineering of fungal NRPSs and for the combinatorial reprogramming of nonribosomal peptide production.

Isolation, Characterization, and Bioherbicidal Potential of the 16-Residue Peptaibols from Emericellopsis sp. XJ1056.

Eco-friendly bioherbicides are urgently needed for managing the problematic weed Amaranthus retroflexus. A mass spectrometry- and bioassay-guided screening approach was employed to identify phytotoxic secondary metabolites from fungi for the development of such bioherbicides. This effort led to the discovery of six phytotoxic 16-residue peptaibols, including five new compounds (2-6) and a known congener (1), from Emericellopsis sp. XJ1056. Their planar structures were elucidated through the analysis of tandem mass and NMR spectroscopic data. The absolute configurations of the chiral amino acids were determined by advanced Marfey's method and chiral-phase liquid chromatography-mass spectrometry (LC-MS) analysis. Bioinformatic analysis and targeted gene disruption identified the biosynthetic gene cluster for these peptaibols. Compounds 1 and 2 significantly inhibited the radicle growth of A. retroflexus seedlings, and 1 demonstrated potent postemergence herbicidal activity against A. retroflexus while exhibiting minimal toxicity to Sorghum bicolor. Structure-activity relationship analysis underscored the importance of trans-4-hydroxy-l-prolines at both the 10th and 13th positions for the herbicidal activities of these peptaibols.