Widespread biosynthesis of 16-carbon terpenoids in bacteria.

Terpenoids are the most diverse group of specialized metabolites with numerous applications. Their biosynthesis is based on the five-carbon isoprene building block and, as a result, almost all terpenoids isolated to date are based on backbones that contain multiples of five carbon atoms. Intrigued by the discovery of an unusual bacterial terpenoid with a 16-carbon skeleton, here we investigate whether the biosynthesis of 16-carbon terpenoids is more widespread than this single example. We mine bacterial genomic information and identify potential C16 biosynthetic clusters in more than 700 sequenced genomes. We study selected clusters using a yeast synthetic biology platform and reveal that the encoded synthases produce at least 47 different noncanonical terpenoids. By thorough chemical analysis, we explain the structures of 13 C16 metabolites, most of which possess intricate highly strained bi- and tricyclic backbones. Our results unveil the existence of an extensive class of terpenoids in bacteria.

Oxetane Ring Formation in Taxol Biosynthesis Is Catalyzed by a Bifunctional Cytochrome P450 Enzyme.

Taxol is a potent drug used in various cancer treatments. Its complex structure has prompted extensive research into its biosynthesis. However, certain critical steps, such as the formation of the oxetane ring, which is essential for its activity, have remained unclear. Previous proposals suggested that oxetane formation follows the acetylation of taxadien-5α-ol. Here, we proposed that the oxetane ring is formed by cytochrome P450-mediated oxidation events that occur prior to C5 acetylation. To test this hypothesis, we analyzed the genomic and transcriptomic information for Taxus species to identify cytochrome P450 candidates and employed two independent systems, yeast (Saccharomyces cerevisiae) and plant (Nicotiana benthamiana), for their characterization. We revealed that a single enzyme, CYP725A4, catalyzes two successive epoxidation events, leading to the formation of the oxetane ring. We further showed that both taxa-4(5)-11(12)-diene (endotaxadiene) and taxa-4(20)-11(12)-diene (exotaxadiene) are precursors to the key intermediate, taxologenic oxetane, indicating the potential existence of multiple routes in the Taxol pathway. Thus, we unveiled a long-elusive step in Taxol biosynthesis.

High-Efficiency, 80 mm Aperture Metalens Telescope.

Metalenses promise potential for a paradigm shift of conventional optical devices. However, the aperture sizes of metalenses are usually bound within hundreds of micrometers by the commonly used fabrication methods, limiting their usage on practical optical devices like telescopes. Here, for the first time, we demonstrate a high-efficiency, single-lens, refractive metalens telescope. We developed a mass production-friendly workflow for fabricating wafer-scale (80 mm aperture) metalenses using deep-ultraviolet (DUV) photolithography. Our metalens works in the near-infrared region with nearly diffraction-limited focal spot sizes and a high peak focusing efficiency of 80.84% at 1450 nm experimentally. Based on the metalens, we built a single-lens telescope and acquired images of the lunar surface, revealing its geographical structures. We believe our demonstration of the metalens telescope proves the exciting potential lying in the metasurfaces and could bring new possibilities for areas involving large optical systems, including geosciences, planetary observation, and astrophysical science.

Near-Field GHz Rotation and Sensing with an Optically Levitated Nanodumbbell.

A levitated nonspherical nanoparticle in a vacuum is ideal for studying quantum rotations and is an ultrasensitive torque detector for probing fundamental particle-surface interactions. Here, we optically levitate a silica nanodumbbell in a vacuum at 430 nm away from a sapphire surface and drive it to rotate at GHz frequencies. The relative linear speed between the tip of the nanodumbbell and the surface reaches 1.4 km s-1 at a submicrometer separation. The rotating nanodumbbell near the surface demonstrates a torque sensitivity of (5.0 ± 1.1) × 10-26 N m Hz-1/2 at room temperature. Moreover, we probed the near-field laser intensity distribution beyond the optical diffraction limit with a nanodumbbell levitated near a nanograting. Our numerical simulations show that the system can measure the Casimir torque and will improve the detection limit of non-Newtonian gravity by several orders of magnitude.

Structurally Diverse Cytotoxic Polyphenols from Garcinia gracilis.

Thirty-five diverse polyphenols, belonging to seven structure classes, were isolated from Garcinia gracilis, a medicinal and edible plant sampled from Laos. The structures of nine new compounds, gargarcilones A-I (1-3, 5-7, 10, 12, and 17), were established using spectroscopic, X-ray diffraction, and experimental and calculated ECD methods. Additionally, we revised the stereochemical assignment of cochinchinoxanthone and cochinchinoxanthone C. The compounds were evaluated for antiproliferative activity against five human tumor cell lines (HL-60, A549, SMMC-7721, MDA-MB-231, and SW480). Compounds 1-4, 7, and 8 exhibited cytotoxic activity with IC50 values of 0.5-8.9 µM. Compound 3 significantly induced apoptosis in SMMC-7721 cells.

Robotic versus Laparoscopic Total Mesorectal Excision Surgery in Rectal Cancer: Analysis of Medium-Term Oncological Outcomes.

Background. Robotic systems can overcome some limitations of laparoscopic total mesorectal excision (L-TME), thus improving the quality of the surgery. So far, many studies have reported the technical feasibility and short-term oncological results of robotic total mesorectal excision (R-TME) in treating rectal cancer (RC); however, only a few evaluated the survival and long-term oncological outcomes. The following study compared the medium-term oncological data, 3-year overall survival (OS), and disease-free survival (DFS) of L-TME and R-TME in patients with rectal cancer. Methods. In this retrospective study, records of patients (patients with stage I-III rectal cancer) who underwent surgery (127 cases of L-TME and 148 cases of R-TME) at the Gansu Provincial Hospital between June 2016 and March 2018 were included in the analysis. Kaplan-Meier analysis evaluated the 3-year OS and DFS for all patients treated with curative intent. Results. The conversion rate was significantly higher, and the postoperative hospital stay was significantly longer in the L-TME group than in the R-TME group (all P<.05). Major complications were significantly lower in the robotic group (P<.05). The 3-year DFS rate (for all stages) was 74.8% for L-TME and 85.8% for R-TME (P = .021). For disease stage III, the 3-year DFS and OS were significantly higher in the R-TME group (P<.05). Conclusion. R-TME can achieve better oncological outcomes and is more beneficial for RC patients compared with L-TME, especially for those with stage III rectal cancers. Nevertheless, further randomized controlled trials and a longer follow-up period are needed to confirm these findings.

Inhibitory effects of simeprevir on Staphylococcusepidermidis and itsbiofilm in vitro. / è¥¿å’ªåŒ¹éŸ¦å¯¹è¡¨çš®è‘¡è„çƒèŒåŠå ¶ç”Ÿç‰©è†œçš„ä½“å¤–æŠ‘åˆ¶ä½œç”¨.

OBJECTIVES: Staphylococcus epidermidis (S. epidermidis) is a Gram-positive opportunistic pathogen that often causes hospital infections. With the abuse of antibiotics, the resistance of S. epidermidis gradually increases, and drug repurposing has become a research hotspot in the treating of refractory drug-resistant bacterial infections. This study aims to study the antimicrobial and antibiofilm effects of simeprevir, an antiviral hepatitis drug, on S. epidermidis in vitro. METHODS: The micro-dilution assay was used to determine the minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) of simeprevir against S. epidermidis. Crystal violet staining assay was used to detect the biofilm inhibitory effect of simeprevir. The antimicrobial activity of simeprevir against S. epidermidis and its biofilm were explored by SYTO9/PI fluorescent staining. The combined effect between simeprevir and gentamycin was assessed by checkerboard assay and was confirmed by time-inhibition assay. RESULTS: Simeprevir showed significant antimicrobial effects against S. epidermidis type strains and clinical isolates with the MIC and MBC at 2-16 µg/mL and 4-32 µg/mL, respectively. The antimicrobial effects of simeprevir were confirmed by SYTO9/PI staining. Simeprevir at MIC could significantly inhibit and break the biofilm on cover slides. Similarly, simeprevir also significantly inhibit the biofilm formation on the surface of urine catheters either in TSB [from (0.700±0.020) to (0.050±0.004)] (t=54.03, P<0.001), or horse serum [from (1.00±0.02) to (0.13±0.01)] (t=82.78, P<0.001). Synergistic antimicrobial effect was found between simeprevir and gentamycin against S. epidermidis with the fractional inhibitory concentration index of 0.5. CONCLUSIONS: Simeprevir shows antimicrobial effect and anti-biofilm activities against S. epidermidis.

Low-complexity adaptive radius outlier removal filter based on PCA for lidar point cloud denoising.

In autonomous driving, cars rely on light detection and ranging (lidar) to navigate the surroundings, but interference from the environment makes it difficult to retrieve useful information. To address this problem, this paper develops a noise reduction method to filter lidar point clouds (i.e., an adaptive radius outlier removal filter based on principal component analysis). We believe this method can outperform existing clustering algorithms when applied to point cloud images captured at a large distance from the lidar. Compared to traditional methods, the proposed method has higher precision and recall with an F-score up to 0.876 and complexity reduced by at least 50%.

First report of Xanthomonas albilineans causing leaf scald on two chewing cane clones in Zhejiang province, China.

In recent years, outbreaks of leaf scald have been reported in two chewing cane clones "Guangdong Huangpi" and "Taoshang Guozhe" in Zhejiang province, China. From May to July 2019, we collected 11 and 13 leaf or stalk samples from symptomatic "Guangdong Huangpi" from four farms in Wenling and "Taoshang Guozhe" clones from three farms in Ruian, Zhejiang province, respectively. Leaves in young plants exhibited white pencil-line streaks (Supplement Fig. 1A & 1D) as well as partial or complete chlorosis of the leaf blade (Supplement Fig. 1B & 1E). Internal symptoms included an orange-red discoloration of the vascular bundles at the basal nodes of the stalk and discoloration extension into the internodes (Supplement Fig. 1C & 1F). Leaf and stalk tissues were used for bacterial isolation and purification on XAS medium, which is selective for Xanthomonas albilineans (Davis et al. 1994), using the streak plate method to obtain 24 isolates (Lin et al. 2018). Circular, convex, smooth, shiny and yellow colonies were isolated from all the samples. The pathogenicity of two isolates, XaCN30 from "Guangdong Huangpi" and XaCN43 from "Taoshang Guozhe", was confirmed with Koch's postulates according to the protocol reported by Lin et al. (2018). The incidences of diseased plants (56% and 63%) were observed in individual host clones at 28 d post-inoculation with isolates XaCN30 and XaCN43, respectively. Furthermore, all isolates were confirmed as X. albilineans via molecular methods. PCR amplification was conducted for all 24 isolates using the primer pairs XgyrB1F/XgyrB1R2 (Ntambo et al. 2019) and XAF1/XAR1 (Wang et al. 1999), which targeting the gyrB (encoding the b subunit of the DNA gyrase) and abc (encoding an ABC transporter) genes, and generating 904 bp and 608 bp amplicons, respectively. The PCR fragments were cloned into the pMD19-T vector (TaKaRa, Dalian, China). For each isolate, three single colonies of transformed Escherichia coli DH5α carrying targeted fragment were sequenced. These sequences were deposited into the GenBank with accession no. MT776053-MT776059 and MT776061-MT776077 for gyrB gene and MT776098-MT776104 and MT776106-MT776122 for abc gene. Based on the two concatenated DNA sequences of our 24 isolates, compared with 27 previously reported X. albilineans isolates obtained from the GenBank database, pairwise sequence identity analysis revealed that all 24 isolates from Zhejiang province had 99.4-100% identity with each other, 99.6-100% identity with 14 published domestic isolates, and 98.3-100% identity with 13 foreign isolates. Furthermore, phylogenetic analysis with MEGA 7.0 (Kumar et al. 2016) showed that the isolates from Zhejiang province clustered into two distinct groups (Supplement Fig. 2). One group consisted of 25 Chinese isolates (including all 11 isolates from Wenling) along with four isolates from the French West Indies (GPE PC73, GPE PC17, GPE PC86, and MTQ032), and one isolate from the USA (XaFL07-1), which were assigned to pulsed-field gel electrophoresis (PFGE) group B (Davis et al. 1997; Pieretti et al. 2012). A putative group was also proposed, which included all 13 isolates from Ruian, indicating that isolates from Ruian are distinct from the isolates isolated from other Chinese sugarcane-planting areas, including Wenling. We conclude that leaf scald disease in local clones of chewing cane are caused by X. albilineans in Zhejiang province in China, which will be helpful for leaf scald management in chewing cane, a cash crop.

Improved Primers for the Specific Detection of Leifsonia xyli subsp. xyli in Sugarcane Using a Conventional PCR Assay.

Ratoon stunting disease (RSD), one of the most important diseases of sugarcane, is caused by the bacterium Leifsonia xyli subsp. xyli (Lxx). Lxx infects sugarcane worldwide and RSD results in high yield losses and varietal degeneration. It is highly challenging to diagnose RSD based on visual symptomatology because this disease does not exhibit distinct external and internal symptoms. In this study, a novel Lxx-specific primer pair Lxx-F1/Lxx-R1 was designed to detect this pathogen using a conventional PCR assay. These primers were then compared with four published Lxx-specific primers and one universal Leifsonia generic primer pair LayF/LayR. Sugarcane leaf samples were collected from Saccharum spp. hybrids in commercial fields (315 samples) and from germplasm clones of five Saccharum species and Erianthus arundinaceus (216 samples). These samples were used for comparative field diagnosis with six conventional PCR assays. Sensitivity tests suggested that the PCR assay with primers Lxx-F1/Lxx-R1 had the same detection limit (1 pg of Lxx genomic DNA) as the primer pairs Cxx1/Cxx2 and CxxITSf#5/CxxITSr#5 and had 10-fold higher sensitivity than the primer pairs Pat1-F2/Pat1-R2, LayF/LayR, and C2F/C2R. Comparison of PCR assays revealed that natural Lxx-infection incidence (6.1%) in field sample evaluation identified by Lxx-F1/Lxx-R1 primers was higher than incidences (0.7 to 3.0%) determined by other primer pairs. Moreover, no nonspecific DNA amplification occurred within these field samples with Lxx-F1/Lxx-R1 primers, unlike with the primer pairs Cxx1/Cxx2 and LayF/LayR. Diverse Leifsonia strains were identified by PCR detection with LayF/LayR primers in the field samples, whereas whether these Leifsonia strains were pathogenic to sugarcane requires further research. Our investigations revealed that the PCR assay with the newly designed primers Lxx-F1/Lxx-R1 could be widely used for RSD diagnosis and Lxx-pathogen detection with satisfactory sensitivity and specificity.

The Median Mandibular Symphysis Tessier 30 Cleft:: 3D Imaging Analysis and Review of the Literature.

Atypical craniofacial clefts of the upper facial region have been well documented; however, the mandibular clefts remain rare and reported as isolated case reports. We report a case of a median mandibular cleft within the context of a Tessier 0-14 axis that we have followed over a 5-year period without surgical/orthodontic intervention. The mandibular symphysis cleft remained open without evidence of the fusion, in contrast to ossification of the metopic dysraphism. Within this context, we present a review of the median mandibular cleft cases from 1819 to 2015.

Cleft Skeletal Asymmetry: Asymmetry Index, Classification and Application.

OBJECTIVE: To quantitatively measure the extent of 3D asymmetry of the facial skeleton in patients with unilateral cleft lip and palate (UCLP) using an asymmetry index (AI) approach, and to illustrate the applicability of the index in guiding and measuring treatment outcome. METHOD: Two groups of subjects between the ages of 15 and 20 who had archived CBCT scan were included in this study. Twenty-five patients with complete UCLP were compared with 50 age-matched noncleft subjects. The CBCT scans were segmented and landmarked for 3D anthropometric analysis. An AI was calculated as a quantitative measure of the extent of facial skeletal asymmetry. RESULTS: For the control group, the AI ranged from 0.72 ± 0.47 at A point to 4.77 ± 1.59 at Gonion. The degree of asymmetry increased with the increasing laterality of the landmark from the midsagittal plane. In the UCLP group, the values of AI significantly increased compared to the control group at nearly all measured landmarks. The extent of the asymmetry to involve the upper, middle, and lower facial skeleton varied widely with the individual patient with UCLP. CONCLUSION: The asymmetry index is capable of capturing the 3D facial asymmetry of subjects with UCLP and as a basis for classification of the extent of the asymmetry. We found the index to be applicable in surgical planning and in measuring the outcome in improving the symmetry in patients who have undergone orthognathic surgery.

Heteroepitaxial Writing of Silicon-on-Sapphire Nanowires.

The heteroepitaxial growth of crystal silicon thin films on sapphire, usually referred to as SoS, has been a key technology for high-speed mixed-signal integrated circuits and processors. Here, we report a novel nanoscale SoS heteroepitaxial growth that resembles the in-plane writing of self-aligned silicon nanowires (SiNWs) on R-plane sapphire. During a low-temperature growth at <350 °C, compared to that required for conventional SoS fabrication at >900 °C, the bottom heterointerface cultivates crystalline Si pyramid seeds within the catalyst droplet, while the vertical SiNW/catalyst interface subsequently threads the seeds into continuous nanowires, producing self-oriented in-plane SiNWs that follow a set of crystallographic directions of the sapphire substrate. Despite the low-temperature fabrication process, the field effect transistors built on the SoS-SiNWs demonstrate a high on/off ratio of >5 × 104 and a peak hole mobility of >50 cm2/V·s. These results indicate the novel potential of deploying in-plane SoS nanowire channels in places that require high-performance nanoelectronics and optoelectronics with a drastically reduced thermal budget and a simplified manufacturing procedure.

[S-Adenosylmethionine Inhibits Expression of Vascular Endothelial Growth Factor-C Protein and Cellular Proliferation in Gastric Cancer].

OBJECTIVE: To explore inhibitory effects of S-adenosylmethionine on vascular endothelial growth factor-C (VEGF-C) protein and cellular proliferation in gastric cancer by regulating methylation status of VEGF-C promoter. METHODS: MTT analyses and nude mice model were employed to examine the effects of S- adenosylmethionine on inhibiting gastric cancer growth in vitro and in vivo. The protein expression of VEGF-C in gastric cancer cells was assessed by Western blot. The methylation status of VEGF-C promoter was assessed by bisulfite genomic DNA sequencing analysis. RESULTS: VEGF-C promoter was hypomethylated in MGC803 and SGC7901. The treatment of S-adenosylmethionine resulted in a heavy hypermethylation of VEGF-C promoter, which consequently down regulated protein level of VEGF-C. S-adenosylmethionine effectively inhibited the growth of gastric cancer cells in vitro and in vivo (P<0. 05). CONCLUSION: S-adenosylmethionine can effectively reverse DNA hypomethylation on VEGF-C promoter which down-regulates VEGF-C protein expression and inhibit gastric cancer growth.

All-optical geometric image transformations enabled by ultrathin metasurfaces.

Image processing plays a vital role in artificial visual systems, which have diverse applications in areas such as biomedical imaging and machine vision. In particular, optical analog image processing is of great interest because of its parallel processing capability and low power consumption. Here, we present ultra-compact metasurfaces performing all-optical geometric image transformations, which are essential for image processing to correct image distortions, create special image effects, and morph one image into another. We show that our metasurfaces can realize binary image transformations by modifying the spatial relationship between pixels and converting binary images from Cartesian to log-polar coordinates with unparalleled advantages for scale- and rotation-invariant image preprocessing. Furthermore, we extend our approach to grayscale image transformations and convert an image with Gaussian intensity profile into another image with flat-top intensity profile. Our technique will potentially unlock new opportunities for various applications such as target tracking and laser manufacturing.

Severe pneumonia with empyema caused by Parvimonas micra and Streptococcus constellatus co-infection: a case report.

Empyema is a common complication of pneumonia, caused by the accumulation of purulent exudate due to pathogenic bacteria invading the pleural cavity. Parvimonas micra and Streptococcus constellatus are pathogens that rarely cause pneumonia with empyema. Herein, a case of severe empyema caused by these two pathogens, confirmed by metagenomic next-generation sequencing (mNGS) of pleural effusion cultures, is reported. A male Chinese patient in his late sixties presented with wheezing, cough, sputum expectoration, and fever. Blood and sputum cultures were negative for pathogens, but the pleural effusion culture was positive for S. constellatus, and was also found to contain P. micra, confirmed by mNGS. The patient's symptoms improved after treatment with cefoperazone/sulbactam and moxifloxacin. Pneumonia caused by P. micra and S. constellatus is rare; however, coinfection with these pathogens may cause severe pneumonia, with or without empyema.

Simeprevir restores the anti-Staphylococcus activity of polymyxins.

Methicillin-resistant Staphylococcus aureus (MRSA) infection poses a severe threat to global public health due to its high mortality. Currently, polymyxins are mainly used for the treatment of Gram-negative bacterial-related infection, while exhibiting limited antibacterial activities against Staphylococcus aureus (S. aureus). However, the combination of antibiotics with antibiotic adjuvants is a feasible strategy for the hard-treated infection and toxicity reducing. We will investigate the antibacterial activity of simeprevir (SIM), which treated for genotype 1 and 4 chronic hepatitis C, combined with polymyxins against MRSA through high-throughput screening technology. In our study, the synergistic antibacterial effect of SIM and polymyxins against S. aureus in vitro was found by checkerboard assay and time-growth curve. The cytotoxicity of SIM combined with polymyxin B sulfate [PB(S)] or polymyxin E (PE) in vitro was evaluated using CCK-8, human RBC hemolysis and scratch assays. In addition, we investigated the eradication of biofilm formation of S. aureus by biofilm inhibition assay and the killing of persister cells. Moreover, we evaluated the therapeutic effect and in vivo toxicity of the combination against MRSA in murine subcutaneous abscess model. Furthermore, it was preliminarily found that SIM significantly enhanced the destruction of MRSA membrane by SYTOX Green and DISC3(5) probes. In summary, these results reveal that the therapy of SIM combined with polymyxins (especially PE) is promising for the treatment of MRSA infection.

Study on the performance of Anerinibacillus sp. in degrading cyanide wastewater and its metabolic mechanism.

Cyanide extraction dominates the gold smelting industry, which leads to the generation of large amounts of cyanide-containing wastewater. In this study, Aneurinibacillus tyrosinisolvens strain named JK-1 was used for cyanide wastewater biodegradation. First, we tested the performance of JK-1 in degrading cyanide under different conditions. Then, we screened metabolic compounds and pathways associated with cyanide degradation by JK-1. Finally, we explored the potential JK-1-mediated cyanide degradation pathway. Our results showed that the optimal pH and temperature for cyanide biodegradation were 7.0 and 30 °C, respectively; under these conditions, a degradation rate of >98% was achieved within 48 h. Untargeted metabolomics results showed that increased cyanide concentration decreased the abundance of metabolic compounds by 71.1% but upregulated 32 metabolic pathways. The Kyoto Encyclopedia of Genes and Genomes enrichment results revealed significant changes in amino acid metabolism pathways during cyanide degradation by JK-1, including cyanoamino acid metabolism, ß-alanine metabolism, and glutamate metabolism. Differential metabolic compounds included acetyl-CoA, l-asparagine, l-glutamic acid, l-phenylalanine, and l-glutamine. These results confirmed that cyanide degradation by JK-1 occurs through amino acid assimilation. This study provides new insights into the mechanism of cyanide biodegradation, which can be applied in the treatment of cyanide wastewater or tailings.

CREB1 alleviates the apoptosis and potentiates the osteogenic differentiation of zoledronic acid-treated human periodontal ligament stem cells via up-regulating VEGF.

Periodontitis represents a severe inflammatory illness in tooth supporting tissue. It has been supported that cAMP response element binding protein 1 (CREB1), a common transcription factor, extensively participates in osteogenic differentiation. Here, the current study was to look into the impacts of CREB1 on the process of periodontitis and its possible action mechanism. After human periodontal ligament stem cells (PDLSCs) were challenged with zoledronic acid (ZA), CREB1 expression was examined with RT-qPCR and western blotting. CCK-8 assay appraised cell activity. Following CREB1 elevation or/and vascular endothelial growth factor (VEGF) silencing in ZA-treated PDLSCs, CCK-8 and TUNEL assays separately estimated cell viability and apoptosis. Western blotting tested the expression of apoptosis- and osteogenic differentiation-associated proteins. ALP staining measured PDLSCs osteogenic ability and ARS staining estimated mineralized nodule formation. JASPAR predicted the potential binding of CREB1 with VEGF promoter, which was then testified by ChIP and luciferase reporter assays. RT-qPCR and western blotting tested VEGF expression. CREB1 expression was declined in ZA-exposed PDLSCs and CREB1 elevation exacerbated the viability and osteogenic differentiation while obstructed the apoptosis of PDLSCs. Additionally, CREB1 bond to VEGF promoter and transcriptionally activated VEGF expression. Further, VEGF absence partially stimulated the apoptosis while suppressed the osteogenic differentiation of CREB1-overexpressing PDLSCs treated by ZA. To be concluded, CREB1 might activate VEGF transcription to obstruct the apoptosis while contribute to the osteogenic differentiation of ZA-treated PDLSCs.

Biosynthesis and biotechnological production of the anti-obesity agent celastrol.

Obesity is a major health risk still lacking effective pharmacological treatment. A potent anti-obesity agent, celastrol, has been identified in the roots of Tripterygium wilfordii. However, an efficient synthetic method is required to better explore its biological utility. Here we elucidate the 11 missing steps for the celastrol biosynthetic route to enable its de novo biosynthesis in yeast. First, we reveal the cytochrome P450 enzymes that catalyse the four oxidation steps that produce the key intermediate celastrogenic acid. Subsequently, we show that non-enzymatic decarboxylation-triggered activation of celastrogenic acid leads to a cascade of tandem catechol oxidation-driven double-bond extension events that generate the characteristic quinone methide moiety of celastrol. Using this acquired knowledge, we have developed a method for producing celastrol starting from table sugar. This work highlights the effectiveness of combining plant biochemistry with metabolic engineering and chemistry for the scalable synthesis of complex specialized metabolites.