Absolute Configuration of Oxabornyl Polyenes Prugosenes A1-A3 and Structural Revision of Prugosene A2.

Oxabornyl polyenes represent a unique group of polyketides characterized by a central polyene core flanked by a conserved oxabornyl moiety and a structurally diverse oxygen heterocyclic ring. They are widely distributed in fungi and possess a variety of biological activities. Due to the significant spatial separation between the two stereogenic ring systems, it is difficult to establish their overall relative configurations. Here, we isolated three oxabornyl polyenes, prugosenes A1-A3 (1-3), from Talaromyces sp. JNU18266-01. Although these compounds were first reported from Penicillium rugulosum, their overall relative and absolute configurations remained unassigned. By employing ozonolysis in combination with ECD calculations, we were able to establish their absolute configurations, and additionally obtained seven new chemical derivatives (4-10). Notably, through NMR data analysis and quantum chemical calculations, we achieved the structural revision of prugosene A2. Furthermore, prugosenes A1-A3 exhibited potent antiviral activity against the respiratory syncytial virus, with compound 1 displaying an IC50 value of 6.3 µM. Our study thus provides a valuable reference for absolute configuration assignment of oxabornyl polyene compounds.

Isolation of new compounds related to xyloketals biosynthesis implies an alternative pathway for furan-fused-chromene formation.

In fungi, there is a rare group of natural products harboring the 2,3,3a,9a-tetrahydro-4H-furo[2,3-b]chromene skeleton, represented by xyloketal B, which display a wide range of biological activities and have drawn significant attention. In this work, four new analogues simpliketals A-D (1-4), as well as two other new compounds simplilactones A and B (5 and 6), were isolated from Simplicillium sp. AHK071-01. Their structures were elucidated by extensive NMR spectroscopic methods, 13C NMR calculation, single-crystal X-ray diffraction, and ECD calculation. In addition, five known compounds (7-11) including alboatrin (7) were also obtained. Based on the structural similarity of the above compounds, we inferred that compounds 5, 6, and 8-11 might be biosynthetically related with 1-4 and 7, which allowed us to propose an alternative biosynthetic route to generate the furan-fused chromene skeleton of this class of compounds, instead of a previously presumed polyketide-terpenoid hybrid pathway. Finally, cytotoxicity assays showed that 1-4 exhibited weak inhibitory activity on PANC-1 cells and that 2 and 3 possessed moderate activity against SH-SY5Y cells.

Efficiency Enhancement Strategies for Stable Bismuth-Based Perovskite and Its Bioimaging Applications.

Lead-free perovskite is one of the ideal solutions for the toxicity and instability of lead halide perovskite quantum dots. As the most ideal lead-free perovskite at present, bismuth-based perovskite quantum dots still have the problem of a low photoluminescence quantum yield, and its biocompatibility also needs to be explored. In this paper, Ce3+ ions were successfully introduced into the Cs3Bi2Cl9 lattice using a modified antisolvent method. The photoluminescence quantum yield of Cs3Bi2Cl9:Ce is up to 22.12%, which is 71% higher than that of undoped Cs3Bi2Cl9. The two quantum dots show high water-soluble stability and good biocompatibility. Under the excitation of a 750 nm femtosecond laser, high-intensity up-conversion fluorescence images of human liver hepatocellular carcinoma cells cultured with the quantum dots were obtained, and the fluorescence of the two quantum dots was observed in the image of the nucleus. The fluorescence intensity of cells cultured with Cs3Bi2Cl9:Ce was 3.20 times of that of the control group and 4.54 times of the control group for the fluorescence intensity of the nucleus, respectively. This paper provides a new strategy to develop the biocompatibility and water stability of perovskite and expands the application of perovskite in the field.

Characterization of a new fusicoccane-type diterpene synthase and an associated P450 enzyme.

Fusicoccane-type terpenoids are a subgroup of diterpenoids featured with a unique 5-8-5 ring system. They are widely distributed in nature and possess a variety of biological activities. Up to date, only five fusicoccane-type diterpene synthases have been identified. Here, we identify a two-gene biosynthetic gene cluster containing a new fusicoccane-type diterpene synthase gene tadA and an associated cytochrome P450 gene tadB from Talaromyces wortmannii ATCC 26942. Heterologous expression reveals that TadA catalyzes the formation of a new fusicoccane-type diterpene talaro-7,13-diene. D2O isotope labeling combined with site-directed mutagenesis indicates that TadA might employ a different C2,6 cyclization strategy from the known fusicoccane-type diterpene synthases, in which a neutral intermediate is firstly formed and then protonated by an environmental proton. In addition, we demonstrate that the associated cytochrome P450 enzyme TadB is able to catalyze multiple oxidation of talaro-7,13-diene to yield talaro-6,13-dien-5,8-dione.

Delayed Postoperative Neurologic Deficit After Spine Deformity Surgery: Analysis of 5377 Cases at 1 Institution.

BACKGROUND: To our knowledge, few studies have focused on delayed postoperative neurologic deficit (DPND) after spine deformity surgery. OBJECTIVES: This study was intended to investigate the incidence, risk factors, treatments, and outcomes of DPND after corrective surgery for spinal deformity in a single spine center. METHODS: The database of a single spine center was queried for dates from 2002 to 2014 to identify all spinal deformity cases. The variables extracted included patient age, diagnosis, procedure, whether neuromonitoring was used and if so which methods were used, whether neuromonitoring abnormalities were detected, whether new neurologic deficits occurred, whether implants were used, and the degree of recovery from new neurologic deficits (none, partial, complete). The patients were classified as pediatric (<21 years old) or adult (≥21 years old). The rates of DPND were tabulated and stratified on the basis of age, diagnosis, and surgical features. RESULTS: A total of 5377 cases were investigated from 2002 through 2014. Seven cases of DPND were reported (incidence, 0.13%). For adult patients, the overall incidence of DPND was 0.17%, and for pediatric patients, it was 0.10%. The incidence of DPND was 0.35% when osteotomies were performed and 0.05% without osteotomies. After the onset of neurologic deficits, loss of somatosensory evoked potentials occurred in 1 patient, and loss of motor evoked potentials occurred in all 7 patients. Revision surgery was performed for 3 patients. At the last follow-up visit, 1 patient experienced no recovery, 2 partial recovery, and 5 complete recovery. CONCLUSIONS: The incidence of DPND is low. Old age and osteotomies are risk factors for DPND. Most patients with DPND experience varying degrees of recovery.