Targeted Discovery of a Natural ortho-Quinone Methide Precursor and Green Generation of Its Oligomers.

ortho-Quinone methides (o-QMs) are a class of highly reactive intermediates that serve as important nonisolable building blocks (NBBs) in organic synthesis and small-molecule library construction. Because of their instability and nonisolability, most reported o-QMs are generated through in situ chemical synthesis, and only a few natural o-QMs have been reported due to the lack of directed discovery strategies. Herein, a new natural o-QM precursor (trichophenol A, 2) was identified from the fungal strain of Trichoderma sp. AT0167 through genome mining, which was generated by trilA (nonreducing polyketide synthase) and trilB (2-oxoglutarate dependent dioxygenase). Combinatorial biosynthesis via two other known NRPKS genes with trilA and trilB was performed, leading to the generation of five new trichophenol o-QM oligomers (trichophenols D-H, 5-9). The strategy combining genome mining with combinatorial biosynthesis not only targetedly uncovered a new natural o-QM precursor but also produced various new molecules through oligomerization of the new o-QM and its designated o-QM acceptors without chemical synthesis and isolation of intermediates, which was named NBB genome mining-combinatorial biosynthesis strategy for o-QM molecule library construction. This study provides a new strategy for the targeted discovery of natural o-QMs and small-molecule library construction with natural o-QMs.

One-year outcomes of a novel venous stent for symptomatic iliofemoral venous obstruction: prospective cohort study.

BACKGROUND: A stent with characteristics of a hybrid design may have advantages in improving the patency of symptomatic iliofemoral vein obstruction. This study assessed the safety and effectiveness of the V-Mixtent Venous Stent in treating symptomatic iliofemoral outflow obstruction. METHODS: Eligible patients had a Clinical-Etiologic-Anatomic-Physiologic (CEAP) C classification of ≥ 3 or a Venous Clinical Severity Score (VCSS) pain score of ≥ 2. The primary safety endpoint was the rate of major adverse events within 30 days. The primary effectiveness endpoint was the 12-month primary patency rate. Secondary endpoints included changes in VCSS from baseline to 6 and 12 months, alterations in CEAP C classification, Chronic Venous Disease Quality of Life Questionnaire (CIVIQ-14) scores at 12 months, and stent durability measures. RESULTS: Between December 2020 and November 2021, 171 patients were enrolled across 15 institutions. A total of 185 endovenous stents were placed, with 91.81% of subjects receiving one stent and 8.19% receiving 2 stents. Within 30 days, only two major adverse events occurred (1.17%; 95% confidence interval [CI], 0.14-4.16%), below the literature-defined performance goal of 11% (P < .001). The 12-month primary patency rate (91.36%; 95% CI, 85.93-95.19%; P < .001) exceeded the literature-defined performance goal. VCSS changes from baseline demonstrated clinical improvement at 6 months (- 4.30 ± 3.66) and 12 months (- 4.98 ± 3.67) (P < .001). Significant reduction in symptoms, as measured by CEAP C classification and CIVIQ-14, was observed from pre-procedure to 12 months (P < .001). CONCLUSIONS: The 12-month outcomes confirm the safety and effectiveness of the V-Mixtent Venous Stent in managing symptomatic iliofemoral venous outflow obstruction, including clinical symptom improvement compared to before treatment.

Identification of three novel P450 enzymes involved in the oxidative modification of a newly discovered fusicoccane diterpene.

Fusicoccane (FC)-type diterpenoids are a class of diterpenoids characterized by a unique 5-8-5 ring system and exhibit diverse biological activities. Recently, we identified a novel FC-type diterpene synthase MgMS, which produces a myrothec-15(17)-en-7-ol (1) hydrocarbon skeleton, however, its tailoring congeners have not been elucidated. Here, we discovered two additional gene clusters Bn and Np, each encoding a highly homologous terpene synthase to MgMS but distinct tailoring enzymes. Heterologous expression of the terpene synthases BnMS and NpMS yielded the same product as MgMS. Subsequent introduction of three P450 enzymes MgP450, BnP450 and NpP450 from individual gene clusters resulted in four new FC-type diterpenoids 2-5. Notably, MgP450 serves as the first enzyme responsible for hydroxylation of the C19 methyl group, whereas NpP450 functions as a multifunctional P450 enzyme involved in the oxidations at C5, C6, and C19 positions of the 5-8-5 tricyclic skeleton. C5 oxidation of the hydrocarbon skeleton 1 led to broadening of the NMR signals and incomplete spectra, which was resolved by high-temperature NMR spectral analysis.

Preoperative prediction of microvascular invasion: new insights into personalized therapy for early-stage hepatocellular carcinoma.

Owing to advances in diagnosis and treatment methods over past decades, a growing number of early-stage hepatocellular carcinoma (HCC) diagnoses has enabled a greater of proportion of patients to receive curative treatment. However, a high risk of early recurrence and poor prognosis remain major challenges in HCC therapy. Microvascular invasion (MVI) has been demonstrated to be an essential independent predictor of early recurrence after curative therapy. Currently, biopsy is not generally recommended before treatment to evaluate MVI in HCC according clinical guidelines due to sampling error and the high risk of tumor cell seeding following biopsy. Therefore, the postoperative histopathological examination is recognized as the gold standard of MVI diagnosis, but this lagging indicator greatly impedes clinicians in selecting the optimal effective treatment for prognosis. As imaging can now noninvasively and completely assess the whole tumor and host situation, it is playing an increasingly important role in the preoperative assessment of MVI. Therefore, imaging criteria for MVI diagnosis would be highly desirable for optimizing individualized therapeutic decision-making and achieving a better prognosis. In this review, we summarize the emerging image characteristics of different imaging modalities for predicting MVI. We also discuss whether advances in imaging technique have generated evidence that could be practice-changing and whether advanced imaging techniques will revolutionize therapeutic decision-making of early-stage HCC.

A Functional Switch Between Asperfumene and Fusicoccadiene Synthase and Entrance to Asperfumene Biosynthesis through a Vicinal Deprotonation-Reprotonation Process.

The diterpene synthase AfAS was identified from Aspergillus fumigatiaffinis. Its amino acid sequence and-according to a structural model-active site architecture are highly similar to those of the fusicocca-2,10(14)-diene synthase PaFS, but AfAS produces a structurally much more complex diterpene with a novel 6-5-5-5 tetracyclic skeleton called asperfumene. The cyclisation mechanism of AfAS was elucidated through isotopic labelling experiments and DFT calculations. The reaction cascade proceeds in its initial steps through similar intermediates as for the PaFS cascade, but then diverges through an unusual vicinal deprotonation-reprotonation process that triggers a skeletal rearrangement at the entrance to the steps leading to the unique asperfumene skeleton. The structural model revealed only one major difference between the active sites: The PaFS residue F65 is substituted by I65 in AfAS. Intriguingly, site-directed mutagenesis experiments with both diterpene synthases revealed that position 65 serves as a bidirectional functional switch for the biosynthesis of tetracyclic asperfumene versus structurally less complex diterpenes.

Functional and structural dissection of glycosyltransferases underlying the glycodiversity of wolfberry-derived bioactive ingredients lycibarbarspermidines.

Lycibarbarspermidines are unusual phenolamide glycosides characterized by a dicaffeoylspermidine core with multiple glycosyl substitutions, and serve as a major class of bioactive ingredients in the wolfberry. So far, little is known about the enzymatic basis of the glycosylation of phenolamides including dicaffeoylspermidine. Here, we identify five lycibarbarspermidine glycosyltransferases, LbUGT1-5, which are the first phenolamide-type glycosyltransferases and catalyze regioselective glycosylation of dicaffeoylspermidines to form structurally diverse lycibarbarspermidines in wolfberry. Notably, LbUGT3 acts as a distinctive enzyme that catalyzes a tandem sugar transfer to the ortho-dihydroxy group on the caffeoyl moiety to form the unusual ortho-diglucosylated product, while LbUGT1 accurately discriminates caffeoyl and dihydrocaffeoyl groups to catalyze a site-selective sugar transfer. Crystal structure analysis of the complexes of LbUGT1 and LbUGT3 with UDP, combined with molecular dynamics simulations, revealed the structural basis of the difference in glycosylation selectivity between LbUGT1 and LbUGT3. Site-directed mutagenesis illuminates a conserved tyrosine residue (Y389 in LbUGT1 and Y390 in LbUGT3) in PSPG box that plays a crucial role in regulating the regioselectivity of LbUGT1 and LbUGT3. Our study thus sheds light on the enzymatic underpinnings of the chemical diversity of lycibarbarspermidines in wolfberry, and expands the repertoire of glycosyltransferases in nature.

Biosynthesis of Enfumafungin-type Antibiotic Reveals an Unusual Enzymatic Fusion Pattern and Unprecedented C-C Bond Cleavage.

Enfumafungin-type antibiotics, represented by enfumafungin and fuscoatroside, belong to a distinct group of triterpenoids derived from fungi. These compounds exhibit significant antifungal properties with ibrexafungerp, a semisynthetic derivative of enfumafungin, recently gaining FDA's approval as the first oral antifungal drug for treating invasive vulvar candidiasis. Enfumafungin-type antibiotics possess a cleaved E-ring with an oxidized carboxyl group and a reduced methyl group at the break site, suggesting unprecedented C-C bond cleavage chemistry involved in their biosynthesis. Here, we show that a 4-gene (fsoA, fsoD, fsoE, fsoF) biosynthetic gene cluster is sufficient to yield fuscoatroside by heterologous expression in Aspergillus oryzae. Notably, FsoA is an unheard-of terpene cyclase-glycosyltransferase fusion enzyme, affording a triterpene glycoside product that relies on enzymatic fusion. FsoE is a P450 enzyme that catalyzes successive oxidation reactions at C19 to facilitate a C-C bond cleavage, producing an oxidized carboxyl group and a reduced methyl group that have never been observed in known P450 enzymes. Our study thus sets the important foundation for the manufacture of enfumafungin-type antibiotics using biosynthetic approaches.

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.

New sesquiterpenoids from Biscogniauxia sp.

Five new sesquiterpenoids, including a campherenane-type (1), a bergamotane-type (2), a drimane-type (3), and two bisabolane-type (5-6) sesquiterpenoids have been isolated from Biscogniauxia sp. 71-10-1-1. Their structures were determined by spectroscopic analyses, quantum chemical ECD calculations,13C chemical shifts calculations, and X-ray crystallography. This is the first report of campherenane-type and drimane-type sesquiterpenoids from Biscogniauxia. Furthermore, the anti-inflammatory assays of all compounds are evaluated, and the results showed that compounds 3 and 7 exhibited the effects against the production of the pro-inflammatory cytokine TNF-α.

Thirteen new peptaibols with antimicrobial activities from Trichoderma sp.

From the fungus Trichoderma sp., we isolated seven novel 18-residue peptaibols, neoatroviridins E-K (1-7), and six new 14-residue peptaibols, harzianins NPDG J-O (8-13). Additionally, four previously characterized 18-residue peptaibols neoatroviridins A-D (14-17) were also identified. The structural configurations of the newly identified peptaibols (1-13) were determined by comprehensive nuclear magnetic resonance (NMR) and high-resolution electrospray ionization tandem mass spectrometry (HR-ESI-MS/MS) data. Their absolute configurations were further determined using Marfey's method. Notably, compounds 12 and 13 represent the first 14-residue peptaibols containing an acidic amino acid residue. In antimicrobial assessments, all 18-residue peptaibols (1-7, 14-17) exhibited moderate inhibitory activities against Staphylococcus aureus 209P, with minimum inhibitory concentration (MIC) values ranging from 8-32 µg·mL-1. Moreover, compound 9 exhibited moderate inhibitory effect on Candida albicans FIM709, with a MIC value of 16 µg·mL-1.

Identification of new bisabosqual-type meroterpenoids reveals non-enzymatic conversion of bisabosquals into seco-bisabosquals.

Bisabosqual-type meroterpenoids are fungi-derived polyketide-terpenoid hybrids bearing a 2,3,3a,3a1,9,9a-hexahydro-1H-benzofuro[4,3,2-cde]chromene skeleton (6/6/6/5 ring system) or its seco-C-ring structure, and exhibit diverse bioactivities. Their unique structural architecture and impressive biological activities have led to considerable interest in discovering new analogues. However, to date, only nine analogues have been identified. Herein, we reported the isolation and identification of six new bisabosqual-type meroterpenoids stachybisbins C-H (1-6), together with one known compound bisabosqual C (7), from Stachybotrys bisbyi PYH05-7. Intriguingly, we found that 7, which contains the intact tetracyclic skeleton, can be non-enzymatically converted into its seco derivative stachybisbin I (8), unveiling the biosynthetic relationship between bisabosquals and seco-bisabosquals. Moreover, based on CRISPR/Cas9-mediated gene disruption, we revealed that the three-gene cluster responsible for the formation of LL-Z1272ß is associated with the biosynthesis of bisabosqual-type meroterpenoids, and then proposed a plausible route to 1-8.

Oxidative aromatization mechanism of ligustilide.

The aromatization mechanisms of ligustilide (1), a versatile monomeric phthalide, were investigated. DFT calculations combined with control experiments prove that the aromatization could result from direct oxidation by triplet oxygen in mild conditions with no catalyst, which is generally thought to be difficult. Moreover, it is predicted that the aromatization could rapidly clear away the harmful-to-organism singlet oxygen, which may be relevant to the general antioxidation activity of phthalides, providing a new point of view to understand the bioactivity from chemical reaction.

Two new alkaloids from a strain of endophytic fungus Aspergillus sp.

19-Hydroxybrevianamide M (1) and 6 R-methoxybrevianamide V (2), two new alkaloids, were isolated from an extract of the endophytic fungus Aspergillus sp. JNU18HC0517J, together with six known analogues (3- 8). Their structures were elucidated by extensive spectroscopic analyses, NMR calculations, and ECD calculations. 6 R-methoxybrevianamide V (2) was the first L-proline indole DKP alkaloid with substitution at C-6 on the proline ring. Furthermore, the cytotoxities and antimicrobial activities of these isolated compounds were also evaluated. Compound 8 exhibited moderate antibacterial activity against Staphylococcus aureus 209 P with a minimal inhibitory concentration (MIC) value of 16 µg/ml.[Figure: see text].

Biosynthetic characterization of the antifungal fernane-type triterpenoid polytolypin for generation of new analogues via combinatorial biosynthesis.

Fernane-type triterpenoids are a small group of natural products mainly found in plants and fungi with a wide range of biological activities. Polytolypin is a representative fernane-type triterpenoid from fungi and possesses potent antifungal activity. So far, biosynthesis of fungal-derived fernane-type triterpenoids has not been characterized, which hinders the expansion of their structural diversity using biosynthetic approaches. Herein, we identified the biosynthetic gene cluster of polytolypin and elucidated its biosynthetic pathway through heterologous expression in Aspergillus oryzae NSAR1, which involves a new triterpene cyclase for the biosynthesis of the hydrocarbon skeleton motiol, followed by multiple oxidations via three P450 enzymes. Moreover, two new triterpene cyclases for the biosynthesis of two other fernane-type skeletons isomotiol and fernenol were identified from fungi, and were individually co-expressed with the three P450 enzymes involved in polytolypin biosynthesis. These studies led to the generation of 13 fernane-type triterpenoids including eight new compounds, and two of them showed stronger antifungal activity towards Candida albicans FIM709 than polytolypin.

DNA dioxygenases Tet2/3 regulate gene promoter accessibility and chromatin topology in lineage-specific loci to control epithelial differentiation.

Execution of lineage-specific differentiation programs requires tight coordination between many regulators including Ten-eleven translocation (TET) family enzymes, catalyzing 5-methylcytosine oxidation in DNA. Here, by using Keratin 14-Cre-driven ablation of Tet genes in skin epithelial cells, we demonstrate that ablation of Tet2/Tet3 results in marked alterations of hair shape and length followed by hair loss. We show that, through DNA demethylation, Tet2/Tet3 control chromatin accessibility and Dlx3 binding and promoter activity of the Krt25 and Krt28 genes regulating hair shape, as well as regulate interactions between the Krt28 gene promoter and distal enhancer. Moreover, Tet2/Tet3 also control three-dimensional chromatin topology in Keratin type I/II gene loci via DNA methylation-independent mechanisms. These data demonstrate the essential roles for Tet2/3 in establishment of lineage-specific gene expression program and control of Dlx3/Krt25/Krt28 axis in hair follicle epithelial cells and implicate modulation of DNA methylation as a novel approach for hair growth control.

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.

Astramalabaricosides A-T, Highly Oxygenated Malabaricane Triterpenoids with Migratory Inhibitory Activity from Astragalus membranaceus var. mongholicus.

Twenty new malabaricane triterpenoids, astramalabaricosides A-T (1-20), were isolated from the roots of Astragalus membranaceus var. mongholicus (Astragali Radix). Their structures were determined by spectroscopic analysis, and the use of the circular dichroism exciton chirality method, quantum chemical calculations, and chemical methods. Malabaricane triterpenoids, an unusual group with the 6-6-5-tricyclic core, are distributed in plants (e.g., Simaroubaceae, Polypodiaceae, and Fabaceae), a marine sponge, and fungi, and their number obtained to date is limited. Compounds 1-20 were characterized as glycosides with a highly oxygenated side chain, and 13-20 were the first cyclic carbonate derivatives among the malabaricane triterpenoids. The stereocluster formed from the continuous hydroxylated chiral carbons in each highly oxygenated side chain and the 6-6-5-tricyclic core system were entirely segregated, and the independent identification of their stereoconfigurations required considerable effort. The migratory inhibitory and antiproliferative activities of 1-20 were evaluated by wound-healing and cell-viability assays, respectively. Most compounds showed significant migratory inhibitory activity, and a preliminary structure-activity relationship was developed. Malabaricane triterpenoids are being reported in the genus Astragalus for the first time.

Value of nonenhanced CT combined with laboratory examinations in the diagnosis of acute suppurative cholecystitis treated with percutaneous cholecystostomy: a retrospective study.

PURPOSES: In this study, we aimed to identify the distribution of presenting laboratory and nonenhanced computed tomography (CT) imaging features within 48 h before percutaneous cholecystostomy (PC) and create a model to appropriately guide the diagnosis of acute suppurative cholecystitis (ASC). METHODS: The study population included 204 acute cholecystitis patients who underwent PC. Based on the timing of the last laboratory and CT examinations before PC, the patients were divided into two groups: within 48 h before PC (Group 1, n = 138) and over 48 h before PC (Group 2, n = 63). The clinical features of the ASC patients in the two groups were compared. A multivariable model for the diagnosis of ASC in the patients in Group 1 was developed. RESULTS: Thirty-nine patients in Group 1 had ASC (28.3%). Gallbladder stones, common bile duct stones, gallbladder wall thickness > 2.85 mm, and neutrophil granulocytes > 82.55% were confirmed to be independent risk factors for ASC. The receiver operating characteristic curve of the recurrence prediction model verified its accuracy (area under the curve: 0.803). Compared with the ASC patients in Group 2, the ASC patients in Group 1 had a higher proportion of pericholecystic exudation or fluid (P = 0.013) and thicker gallbladder walls (P = 0.033). CONCLUSIONS: Using nonenhanced CT imaging features and cutoffs for neutrophil granulocytes, we were able to identify a simple algorithm to discriminate ASC. The degree of local inflammation of the gallbladder in ASC patients progressively increases over time, and these changes can be observed on nonenhanced CT images. However, the symptoms of abdominal pain are of little help in estimating the disease duration in elderly patients.

Percutaneous cholecystostomy as a definitive treatment for moderate and severe acute acalculous cholecystitis: a retrospective observational study.

BACKGROUND: In this study, we aimed to investigate risk factors for the relapse of moderate and severe acute acalculous cholecystitis (AAC) patients after initial percutaneous cholecystostomy (PC) and to identify the predictors of patient outcomes when choosing PC as a definitive treatment for AAC. MATERIALS AND METHODS: The study population comprised 44 patients (median age 76 years; range 31-94 years) with moderate or severe AAC who underwent PC without subsequent cholecystectomy. According to the results of follow-up (followed for a median period of 17 months), the data of patients with recurrence versus no recurrence were compared. Patients were divided into the death and non-death groups based on patient status within 60 days after PC. RESULTS: Twenty-one (47.7%) had no recurrence of cholecystitis during the follow-up period after catheter removal (61-1348 days), six (13.6%) experienced recurrence of cholecystitis after PC, and 17 (38.6%) patients died during the indwelling tube period (5-60 days). The multivariate analysis showed that coronary heart disease (CHD) or congestive heart failure (odds ratio [OR] 26.50; 95% confidence interval [CI] 1.21-582.06; P = 0.038) was positively correlated with recurrence. The age-adjusted Charlson comorbidity index (OR 1.53; 95% CI 1.08-2.17; P = 0.018) was independently associated with 60-day mortality after PC. CONCLUSIONS: Our results suggest that CHD or congestive heart failure was an independent risk factor for relapse in moderate and severe AAC patients after initial PC. AAC patients with more comorbidities had worse outcomes.

Two New Diterpenoids from Biscogniauxia sp. and Their Activities.

Two new diterpenoids, including a seco-isopimarane type (1) and an abietane type (2), were isolated from Biscogniauxia sp. (71-10-1-1). Their structures, including absolute configurations, were elucidated by NMR spectroscopic analyses, X-ray crystallography, 13C chemical shifts calculations, and ECD calculations. This is the first report of diterpenoids from Biscogniauxia sp. Furthermore, short-term memory enhancement against Alzheimer's disease (AD), anti-inflammatory, and cytotoxic activities of 1-2 were also evaluated. The results showed that compound 1 exhibited short-term memory enhancement activity against AD.