New Sulfurated Butyrolactones from the Fungus Penicillium janthinellum.

Deep-sea derived fungi are considered as significant resources to discovery structurally diverse and biologically active natural compounds. In this study, four new sulfurated butyrolactones, penijanthiones A-D (1-4), together with four known analogues (5-8), were isolated from a Mariana Trench-derived fungus Penicilliumjanthinellum SH0301. Compounds 1-4 were the undescribed examples for natural butyrolactones coupling with a mercaptolactate moiety. Their structures including the absolute configurations of these new compounds were elucidated by comprehensive spectroscopic data, and calculated electronic circular dichroism (ECD). The plausible biosynthetic pathway of sulfur-incorporation of 1-4 was proposed. All of these isolated compounds were evaluated their cytotoxic, antimicrobial and antiviral activities.

Long-term distress throughout one's life: health-related quality of life, economic and caregiver burden of patients with neurofibromatosis type 1 in China.

Introduction: Neurofibromatosis type 1 (NF1) is a rare genetic disorder, with lack of evidence of disease burden in China. We aimed to describe the economic burden, health-related quality of life (HRQL), and caregiver burden of NF1 patients in China. Methods: We conducted an online cross-sectional survey employing the China Cloud Platform for Rare Diseases, with 223 caregivers of NF1 pediatric patients (patients under 18), and 226 adult patients. Economic burden was estimated using direct and indirect costs related to NF1 in 2021, and the Work Productivity and Activity Impairment Questionnaire: General Health V2.0 (WPAI-GH). HRQL measures included EQ-5D-Y proxy version and PedsQL™ 4.0 Generic Core Scales (PedsQL GCS) proxy version for pediatric patients, and EQ-5D-5L and PedsQL™ 3.0 Neurofibromatosis Module (PedsQL NFM) for adult patients. Caregiver burden was estimated by Zarit Burden Interview (ZBI). Results: For pediatric patients, the average direct cost in 2021 was CNY 33,614 (USD 4,879), and employed caregivers' annual productivity loss was 81 days. EQ-5D-Y utility was 0.880 ± 0.13 and VAS score was 75.38 ± 20.67, with 52.6% patients reporting having problems in "pain/discomfort" and 42.9% in "anxiety/depression." PedsQL GCS total score was 68.47 ± 19.42. ZBI score demonstrated that 39.5% of caregivers had moderate-to-severe or severe burden. For adult patients, average direct cost in 2021 was CNY 24,531 (USD 3,560). Patients in employment reported an absenteeism of 8.5% and presenteeism of 21.6% according to the results of WPAI-GH. EQ-5D-5L utility was 0.843 ± 0.17 and VAS score was 72.32 ± 23.49, with more than half of patients reporting having problems in "pain/discomfort" and "anxiety/depression" dimensions. PedsQL NFM total score was 68.40 ± 15.57. Conclusion: Both pediatric and adult NF1 patients in China had a wide-ranging economic burden and low HRQL, especially in the psychological dimension. Caregivers for NF1 pediatric patients experienced considerable caregiver burden. More attention and support from policymakers and stakeholders are required to relieve NF1 patients' and caregivers' distress.

Substrate specificity of a branch of aromatic dioxygenases determined by three distinct motifs.

The inversion of substrate size specificity is an evolutionary roadblock for proteins. The Duf4243 dioxygenases GedK and BTG13 are known to catalyze the aromatic cleavage of bulky tricyclic hydroquinone. In this study, we discover a Duf4243 dioxygenase PaD that favors small monocyclic hydroquinones from the penicillic-acid biosynthetic pathway. Sequence alignments between PaD and GedK and BTG13 suggest PaD has three additional motifs, namely motifs 1-3, distributed at different positions in the protein sequence. X-ray crystal structures of PaD with the substrate at high resolution show motifs 1-3 determine three loops (loops 1-3). Most intriguing, loops 1-3 stack together at the top of the pocket, creating a lid-like tertiary structure with a narrow channel and a clearly constricted opening. This drastically changes the substrate specificity by determining the entry and binding of much smaller substrates. Further genome mining suggests Duf4243 dioxygenases with motifs 1-3 belong to an evolutionary branch that is extensively involved in the biosynthesis of natural products and has the ability to degrade diverse monocyclic hydroquinone pollutants. This study showcases how natural enzymes alter the substrate specificity fundamentally by incorporating new small motifs, with a fixed overall scaffold-architecture. It will also offer a theoretical foundation for the engineering of substrate specificity in enzymes and act as a guide for the identification of aromatic dioxygenases with distinct substrate specificities.

Theoretical study of the substituent effects on the ESIPT mechanism of salicylideneaniline and the TICT photochemistry reactions.

The study of salicylideneaniline (SA) and its derivatives is critical due to their special photophysical properties and environmental sensitivity. In this work, the density time-dependent functional theory (TDDFT) and complete-active-space self-consistent-field (CASSCF) methods were carried out to calculate the substituent effect on excited-state properties and dynamics of SA derivatives. We found the para-substitution triggers the excited-state intramolecular proton transfer (ESIPT) reaction, exhibiting the dual-fluorescent phenomena. However, the meta- and ortho-substitutions impel the non-radiative transition process along the minimum energy conical intersection (MECI), forming the twisted intramolecular charge transfer (TICT) state to prevent ESIPT. This investigation of substituent effects on the photochemical processes and photophysical properties will provide the benchmarks for the design of fluorescent materials.

Synthetic Nicotinamide Cofactors as Alternatives to NADPH in Imine Reductase-Catalyzed Reactions.

This study demonstrates the effectiveness of synthetic nicotinamide cofactors as cost-effective alternatives to NADPH in imine reductase (IRED) catalysis. The synthetic cofactors maintained catalytic activity and stereoselectivity, achieving high conversion rates. Molecular docking studies revealed key structural interactions influencing performance. Combining a glucose dehydrogenase (GDH) recycling system further enhanced the stability and efficiency. These findings highlight the potential of synthetic cofactors to reduce costs and improve the feasibility of IRED-catalyzed processes for industrial applications.

Coronary heart disease increases the risk of perioperative ischemic stroke after noncardiac surgery: A retrospective cohort study.

OBJECTIVE: To investigate the association between coronary heart disease (CHD) and the risk of perioperative ischemic stroke in patients undergoing noncardiac surgery. METHODS: This retrospective study evaluated the incidence of ischemic stroke within 30 days after a noncardiac surgery. A cohort of 221,541 patients who underwent noncardiac surgery between January 2008 and August 2019 was segregated according to whether they were diagnosed with CHD. Primary, sensitivity, and subgroup logistic regression analyses were conducted to confirm that CHD is an independent risk factor for perioperative ischemic stroke. Propensity score matching analysis was used to account for the potential residual confounding effect of covariates. RESULTS: Among the 221,541 included patients undergoing noncardiac surgery, 484 patients (0.22%) experienced perioperative ischemic stroke. The risk of perioperative ischemic stroke was higher in patients with CHD (0.7%) compared to patients without CHD (0.2%), and multivariate logistic regression analysis showed that CHD was associated with a significantly increased risk of perioperative ischemic stroke (odds ratio (OR), 3.7943; 95% confidence interval (CI) 2.865-4.934; p < 0.001). In a subset of patients selected by propensity score matching (PSM) in which all covariates between the two groups were well balanced, the association between CHD and increased risk of perioperative ischemic stroke remained significantly significant (OR 1.8150; 95% CI, 1.254-2.619; p = 0.001). In the subgroup analysis stratified by age, preoperative ß-blockers, and fibrinogen-to-albumin ratio (FAR), the association between CHD and perioperative ischemic stroke was stable (p for interaction >0.05). Subgroup analyses also showed that CHD was significantly increased the risk of perioperative ischemic stroke in the preoperative mean arterial pressure (MAP) ≥94.2 mmHg subgroups (p for interaction <0.001). CONCLUSION: CHD is significantly associated with an increased risk of perioperative ischemic stroke and is an independent risk factor for perioperative ischemic stroke after noncardiac surgery. Strict control of preoperative blood pressure may reduce the risk of perioperative ischemic stroke for patients with CHD undergoing noncardiac surgery.

Metabolic profiling of different parts of Physalis alkekengi L. var. franchetii (Mast.) Makino based on UPLC-Q-Orbitrap-HRMS coupled with bioactivity assays.

Physalis alkekengi L.var. franchetii (Mast.) Makino (PAF) is an important edible and medicinal plant resource in China. Historically, phytochemical studies have primarily examined the calyx and fruit due to their long-standing use in traditional Chinese medicine for their ability to clear heat and detoxify. Metabolites and bioactivities of other parts such as the leaves, stems and roots, are rarely studied. The study involved conducting metabolic profiling of five plant parts of PAF using UPLC-Q-Orbitrap-HRMS analysis, in conjunction with two bioactivity assays. A total of 95 compounds were identified, including physalins, flavonoids, sucrose esters, phenylpropanoids, nitrogenous compounds and fatty acids. Notably, 14 aliphatic sucrose esters, which are potentially novel compounds, were initially identified. Furthermore, one new aliphatic sucrose ester was purified and its structure was elucidated by 1D and 2D NMR analysis. The hierarchical clustering analysis and principal component analysis showed the close clustering of the root and stem, suggesting similarities in their chemical composition, whereas the leaf, calyx and fruit clustered more distantly. Orthogonal partial least-squares discriminant analysis results showed that 41 compounds potentially serve as marker compounds for distinguishing among plant parts. Variations in activity were observed among the plant parts during the comparative evaluation with biological assays. The calyx, leaf and fruit extracts showed stronger antibacterial and anti-inflammatory activities than the stem and root extracts, and 19 potential biomarkers were identified by S-plot analysis for the observed activities, including chlorogenic acid, luteolin, cynaroside, physalin A, physalin F, physalin J, apigetrin, quercetin-3ß-D-glucoside and five ASEs, which likely explain the observed potent bioactivity.

Distribution of the active components from Xianglian Pill in tissues of healthy and antibiotic-associated diarrhea model mice and the mechanism study.

Antibiotic-associated diarrhea (AAD) is a common side effect of antibiotic therapy, characterized by intestinal inflammation which reduces the quality of life of patients. Xianglian Pill (XLP) has long been used to treat abdominal pain, diarrhea, bacillary dysentery and enteritis. Studies found that XLP has curative effect on AAD; however, the chemical constituents and mechanism of XLP have not been fully elucidated because of the lack of in vitro and in vivo studies. In this study, ultra-high performance liquid chromatography mass spectrometry method (UPLC-Q-Exactive-Orbitrap-HRMS) was used to examine the components of the XLP. Then, the binding between active compounds and the key targets was studied using network pharmacology and molecular docking. A comparative tissue distribution study was established for the simultaneous determination of the 10 active components in healthy and AAD mouse models. Forty-six components were characterized from XLP. According to the network pharmacology degree value, a prediction was made that encompassed 42 components and 14 core targets, which were intricately involved in crucial biological pathways, such as the AGE-RAGE signaling, cellular senescence, and MAPK signaling. Tissue distribution analysis showed that the 10 components were widely distributed in the heart, liver, spleen, lungs, kidneys, small intestine, and large intestine of mice, with varying concentrations in healthy and AAD mice. Molecular docking analysis also indicated that the active compounds in the tissue distribution could bind tightly to key targets of network pharmacological studies. This study provides a reference for further investigations of the relationships between the chemical components and pharmacological activities of XLP.

Comparative transcriptomic insights into molecular mechanisms of the susceptibility wheat variety MX169 response to Puccinia striiformis f. sp. tritici (Pst) infection.

Stripe rust of wheat is caused by the fungal pathogen Puccinia striiformis f. sp. tritici (Pst). Breeding durably resistant wheat varieties by disrupting the susceptibility (S) gene has an important impact on the control of wheat stripe rust. Mingxian169 (MX169) showed strong stripe rust susceptibility to all the races of Pst. However, molecular mechanisms and responsive genes underlying susceptibility of the wheat variety MX169 to Pst have not been elucidated. Here, we utilized next-generation sequencing technology to analyze transcriptomics data of "MX169" and high-resistance wheat "Zhong4" at 24, 48, and 120 h post-inoculation (hpi) with Pst. Comparative transcriptome analysis revealed 3,494, 2,831, and 2,700 differentially expressed genes (DEGs) at different time points. We observed an upregulation of DEGs involved in photosynthesis, flavonoid biosynthesis, pyruvate metabolism, thiamine metabolism, and other biological processes, suggesting their involvement in MX169's response to Pst. DEGs encoding transcription factors were also identified. Our study suggested the potential susceptibility gene resources in MX169 related to stripe rust response could be valuable for understanding the mechanisms involved in stripe rust susceptibility and for improving wheat resistance to Pst. IMPORTANCE: Our study suggests the potential susceptibility gene resources in MX169 related to stripe rust response could be valuable for understanding the mechanisms involved in stripe rust susceptibility and for improving wheat resistance to Pst.

Structural Optimization of Marine Natural Product Pretrichodermamide B for the Treatment of Colon Cancer by Targeting the JAK/STAT3 Signaling Pathway.

Marine natural product (MNP) pretrichodermamide B (Pre B, 9) was identified as a novel STAT3 inhibitor in our previous work, while its metabolic instability hindered its further development. To address this drawback, ligand structure-based drug design was adopted leading to a series of Pre B derivatives. Among them, MNP trichodermamide B (tri B, 24) obtained by skeletal rearrangement exhibited more potent antiproliferative activity with an IC50 value of 0.12 µM against HCT116. Notably, 24 stood out with improved metabolic stability (T1/2 = 31 min) and more favorable oral bioavailability (F = 37.5%). Further studies indicated that 24 blocked JAK/STAT3 signaling in dose- and time-dependent manner. In vivo, 24 suppressed tumor growth (TGI = 65%) at a dose of 20 mg/kg in a HCT116-derived xenograft mouse model. Overall, 24 might be a promising lead compound for colon cancer and is worthy of further investigation.

Resolving syntactic-semantic conflicts: comprehension and processing patterns by deaf Chinese readers.

The current study combined sentence plausibility judgment and self-paced reading tasks to examine the comprehension strategies and processing patterns of Chinese deaf individuals when comprehending written Chinese sentences with syntactic-semantic cue conflicts. Similar to findings from previous crosslinguistic studies on deaf readers, the Chinese deaf readers showed great variability in their comprehension strategies, with only 38% robustly relying on syntactic cues. Regardless of their overall comprehension preferences, the deaf readers all showed additional processing efforts as reflected by longer reading time at the verb regions when they relied on the syntactic cues. Those with less robust reliance on syntactic cues also showed longer reading time at the verb regions even when they relied on the semantic cues, suggesting sensitivity to the syntactic cues regardless of the comprehension strategy. These findings suggest that deaf readers in general endure more processing burden while resolving conflicting syntactic and semantic cues, likely due to their overall high reliance on semantic information during sentence comprehension. Increased processing burden thus may contribute to an overall tendency of over-reliance on semantic cues when comprehending sentences with cue conflicts.

Prelimbic cortical pyramidal neurons to ventral tegmental area projections promotes arousal from sevoflurane anesthesia.

AIMS: General anesthesia has been used in surgical procedures for approximately 180 years, yet the precise mechanism of anesthetic drugs remains elusive. There is significant anatomical connectivity between the ventral tegmental area (VTA) and the prelimbic cortex (PrL). Projections from VTA dopaminergic neurons (VTADA ) to the PrL play a role in the transition from sevoflurane anesthesia to arousal. It is still uncertain whether the prelimbic cortex pyramidal neuron (PrLPyr ) and its projections to VTA (PrLPyr -VTA) are involved in anesthesia-arousal regulation. METHODS: We employed chemogenetics and optogenetics to selectively manipulate neuronal activity in the PrLPyr -VTA pathway. Electroencephalography spectra and burst-suppression ratios (BSR) were used to assess the depth of anesthesia. Furthermore, the loss or recovery of the righting reflex was monitored to indicate the induction or emergence time of general anesthesia. To elucidate the receptor mechanisms in the PrLPyr -VTA projection's impact on anesthesia and arousal, we microinjected NMDA receptor antagonists (MK-801) or AMPA receptor antagonists (NBQX) into the VTA. RESULTS: Our findings show that chemogenetic or optogenetic activation of PrLPyr neurons prolonged anesthesia induction and promoted emergence. Additionally, chemogenetic activation of the PrLPyr -VTA neural pathway delayed anesthesia induction and promoted anesthesia emergence. Likewise, optogenetic activation of the PrLPyr -VTA projections extended the induction time and facilitated emergence from sevoflurane anesthesia. Moreover, antagonizing NMDA receptors in the VTA attenuates the delayed anesthesia induction and promotes emergence caused by activating the PrLPyr -VTA projections. CONCLUSION: This study demonstrates that PrLPyr neurons and their projections to the VTA are involved in facilitating emergence from sevoflurane anesthesia, with the PrLPyr -VTA pathway exerting its effects through the activation of NMDA receptors within the VTA.

Sevoflurane exerts antidepressant-like effects via the BDNF-TrkB pathway.

Depression has emerged as the predominant psychiatric affliction affecting individuals. Prior research has substantiated the antidepressant properties exhibited by numerous anesthetics. Sevoflurane, a widely utilized inhalant anesthetic in clinical practice, remains relatively uncharted in terms of its specific antidepressant effects. In this study, we used open field test, forced swimming test and novelty-suppressed feeding test to investigate the anxiety and depression-like behaviors in C57BL/6 mice following the inhalation of sevoflurane. We then used western blotting to scrutinized the expression levels of proteins associated with the brain-derived neurotrophic factor (BDNF)-tryosine receptor kinase B (TrkB) pathway in the hippocampus and prefrontal cortex. To further investigate whether sevoflurane exerts antidepressant-like effects via the BDNF-TrkB pathway, we downregulated TrkB expression by administering siRNA into the lateral ventricle. We found that the inhalation of 2.5 % sevoflurane exerted a significant antidepressant-like effect, accompanied by an elevation in p-TrkB expression levels in the hippocampus and prefrontal cortex. Intriguingly, this antidepressant-like effect was abrogated following the downregulation of TrkB expression through the microinjection of siRNA into the lateral ventricle. In conclusion, this study provides evidence supporting the notion that sevoflurane exerts its antidepressant-like effect via the BDNF-TrkB signaling pathway.

A flame-retardant and conductive fabric-based triboelectric nanogenerator: Application in fire alarm and emergency evacuation.

The fabrics commonly used in architectural decorative materials pose significant fire hazards due to their flammability and rapid fire spread. Moreover, the traditional fire-alarm systems may fail to function properly in complex fire environments owing to power supply disruptions. In this study, we developed a low-cost and eco-friendly flame-retardant conductive fabric-based triboelectric nanogenerator (FCF-TENG) by integrating flame-retardant conductive nylon fabric and polytetrafluoroethylene soaked cotton fabric. This nanogenerator exhibits excellent flame-retardant properties and remarkable energy-harvesting capabilities. The nylon fabric, treated with layer-by-layer self-assembly method, possesses outstanding self-extinguishing capability and melt-dripping resistance. Additionally, the electrical performance of FCF-TENG significantly improves, with a 10-fold boost in conductivity, and the open-circuit voltage increases by 84% to 92 V. Besides, by incorporating the rectifier circuit, the FCF-TENG is capable of completely charging a 1 µF capacitor within 30 s. Furthermore, the FCF-TENG was successfully applied as a self-powered sensor in the fire-alarm system and served as a safety exit indicator for evacuees and fire rescue. This work presents an effective and innovative application of multifunctional smart textiles for energy harvesting and self-powered sensing.

Host-parasite interactions: a study on the pathogenicity of different Mesanophrys sp. densities and hemocytes-mediated parasitic resistance of swimming crabs (Portunus trituberculatus).

Mesanophrys sp. is a parasitic ciliate that invades and destroys the hemocytes of the swimming crab (Portunus trituberculatus). In the present study, we employed an in vitro model to elucidate how Mesanophrys sp. destroys crab hemocytes. We also evaluated the relationship between the parasite's density, the destruction rate of the hemocytes, and the rapid proliferation pattern of parasites in host crabs. We found that the survival rate and cell integrity of crab hemocytes decreased with an increase in Mesanophrys sp. density, depicting a negative correlation between hemocyte viability and parasite density. Further analyses revealed that crab hemocytes could resist destruction by a low density (10 ind/mL) of Mesanophrys sp. for a long time (60 h). Mesanophrys sp. and its culture medium (containing the ciliate secretions) destroy the host hemocytes. The natural population growth rate of Mesanophrys sp. decreased with an increase in the parasite density, but the Mesanophrys sp. density did not affect the generation time of the parasites. In summary, Mesanophrys sp. can destroy crab hemocytes, and the degree of destruction is directly proportional to the parasite density. The resistance of crab hemocytes to Mesanophrys sp. decreased gradually with an increase in the parasite density.

A deep lung cell atlas reveals cytokine-mediated lineage switching of a rare cell progenitor of the human airway epithelium.

The human airway contains specialized rare epithelial cells whose roles in respiratory disease are not well understood. Ionocytes express the Cystic Fibrosis Transmembrane Conductance Regulator (CFTR), while chemosensory tuft cells express asthma-associated alarmins. However, surprisingly, exceedingly few mature tuft cells have been identified in human lung cell atlases despite the ready identification of rare ionocytes and neuroendocrine cells. To identify human rare cell progenitors and define their lineage relationship to mature tuft cells, we generated a deep lung cell atlas containing 311,748 single cell RNA-Seq (scRNA-seq) profiles from discrete anatomic sites along the large and small airways and lung lobes of explanted donor lungs that could not be used for organ transplantation. Of 154,222 airway epithelial cells, we identified 687 ionocytes (0.45%) that are present in similar proportions in both large and small airways, suggesting that they may contribute to both large and small airways pathologies in CF. In stark contrast, we recovered only 3 mature tuft cells (0.002%). Instead, we identified rare bipotent progenitor cells that can give rise to both ionocytes and tuft cells, which we termed tuft-ionocyte progenitor cells (TIP cells). Remarkably, the cycling fraction of these TIP cells was comparable to that of basal stem cells. We used scRNA-seq and scATAC-seq to predict transcription factors that mark this novel rare cell progenitor population and define intermediate states during TIP cell lineage transitions en route to the differentiation of mature ionocytes and tuft cells. The default lineage of TIP cell descendants is skewed towards ionocytes, explaining the paucity of mature tuft cells in the human airway. However, Type 2 and Type 17 cytokines, associated with asthma and CF, diverted the lineage of TIP cell descendants in vitro , resulting in the differentiation of mature tuft cells at the expense of ionocytes. Consistent with this model of mature tuft cell differentiation, we identify mature tuft cells in a patient who died from an asthma flare. Overall, our findings suggest that the immune signaling pathways active in asthma and CF may skew the composition of disease-relevant rare cells and illustrate how deep atlases are required for identifying physiologically-relevant scarce cell populations.

Economic and Humanistic Burden of Osteoarthritis: An Updated Systematic Review of Large Sample Studies.

OBJECTIVE: A previous systematic literature review demonstrated a significant economic and humanistic burden on patients with osteoarthritis (OA). The aim of this study was to systematically review and update the burden of OA reported by large sample studies since 2016. METHODS: We searched Medline (via Ovid) and Embase using the updated search strategy based on the previous review. Those studies with a sample size ≥ 1000 and measuring the cost (direct or indirect) or health-related quality of life (HRQL) of OA were included. Pairs of reviewers worked independently and in duplicate. An arbitrator was consulted to resolve discrepancies between reviewers. The Kappa value was calculated to examine the agreement between reviewers. All costs were converted to 2021 US dollars according to inflation rates and exchange rates. RESULTS: A total of 1230 studies were screened by title and abstract and 159 by full text, and 54 studies were included in the review. The Kappa value for the full-text screening was 0.71. Total annual OA-related direct costs ranged from US$326 in Japan to US$19,530 in the US. Total annual all-cause direct costs varied from US$173 in Italy to US$41,433 in the US. The annual indirect costs ranged from US$736 in the US to US$18,884 in the Netherlands. Thirty-four studies reported HRQL, with EQ-5D (13, 38%) and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) (6, 18%) being the most frequently used instruments. The EQ-VAS and utility scores ranged from 41.5 to 81.7 and 0.3 to 0.9, respectively. The ranges of WOMAC pain (range 0-20, higher score for worse health), stiffness (range 0-8), and physical functioning (range 0-68) were 2.0-3.0, 1.0-5.0, and 5.8-42.8, respectively. CONCLUSION: Since 2016, the ranges of direct costs of OA became wider, while the HRQL of patients remained poor. More countries outside the US have published OA-related disease burden using registry databases.

Semi-rational design of an imine reductase for asymmetric synthesis of alkylated S-4-azepanamines.

Although imine reductase (IRED)-catalyzed reductive amination is promising for the synthesis of alkylated chiral amines, precisely regulating the stereoselectivity of IRED remains a great challenge. Herein, focusing on the residues directly in contact with the ketone moiety, we applied structure-guided semi-rational design to obtain the triple-mutant I149Y/L200H/W234K. This mutant showed high stereoselectivity, of up to >99% (S), toward reductive amination of N-Boc-4-oxo-azepane and different amines, and to the best of our knowledge is the first biocatalyst developed for asymmetric synthesis of chiral azepane-4-amines.

Identification of marine natural product Pretrichodermamide B as a STAT3 inhibitor for efficient anticancer therapy.

The Janus kinase (JAK)/signal transducer and activator of transcription 3 (STAT3) regulates the expression of various critical mediators of cancer and is considered as one of the central communication nodes in cell growth and survival. Marine natural products (MNP) represent great resources for discovery of bioactive lead compounds, especially anti-cancer agents. Through the medium-throughput screening of our in-house MNP library, Pretrichodermamide B, an epidithiodiketopiperazine, was identified as a JAK/STAT3 signaling inhibitor. Further studies identified that Pretrichodermamide B directly binds to STAT3, preventing phosphorylation and thus inhibiting JAK/STAT3 signaling. Moreover, it suppressed cancer cell growth, in vitro, at low micromolar concentrations and demonstrated efficacy in vivo by decreasing tumor growth in a xenograft mouse model. In addition, it was shown that Pretrichodermamide B was able to induce cell cycle arrest and promote cell apoptosis. This study demonstrated that Pretrichodermamide B is a novel STAT3 inhibitor, which should be considered for further exploration as a promising anti-cancer therapy. Supplementary Information: The online version contains supplementary material available at 10.1007/s42995-022-00162-x.

Effects of solvent polarity on the novel excited-state intramolecular thiol proton transfer and photophysical property compared with the oxygen proton transfer.

Recently, the dual-fluorescent phenomena of excited state intramolecular thiol proton transfer (ESIPT) for 3-thiolflavone derivative (3NTF) were reported by Chou and coworkers for the first time [J. Am. Chem. Soc. 143 (2021) 12715-12724], which opened a new chapter in the field of ESIPT. Based on density functional theory (DFT) and time-dependent density functional theory (TDDFT), the proton transfer processes of 3NTF in toluene, dichloromethane and acetonitrile were studied. By optimizing the structure of the ground (S0) state and first excited (S1) state of 3NTF in different solvents, the hydrogen-bond parameters and proton-transfer potential energy curves were calculated. It was shown that although photo-excitation enhanced the intramolecular hydrogen bonding strength and thus promoted the occurrence of ESIPT, the solvent polarities inhibited the enhancement of the hydrogen bond of S1 state, which was not conducive to ESIPT. The electron spectra analyses were consistent with experimental data, which confirmed the rationality of molecular configurations. The time-evolved excited state dynamics simulation was performed based on the optimized structure of 3NTF, indicating that the ESIPT was an ultrafast photochemical reaction less than 180 fs. Moreover, we compared the potential energy surfaces of ESIPT, electronic structures based on natural transition orbitals (NTOs) method and electron-hole isosurfaces for the 3NTF and the traditional flavone molecule (3NHF), concluded that the unusually large Stokes shift fluorescence of 3NTF was mainly caused by the coupling of ESIPT and twisting intramolecular charge transfer (TICT), and the 3NTF isomer had the more nπ* character in the electron transition process. The nπ* ICT significantly increased with the decrease of solvent polarities, affecting the molecular photophysical properties, this made it more widely used in biomedical, photochemical, materials science and other fields.