Total syntheses of (-)-macrocalyxoformins A and B and (-)-ludongnin C.

The complex and diverse molecular architectures along with broad biological activities of ent-kauranoids natural products make them an excellent testing ground for the invention of synthetic methods and strategies. Recent efforts notwithstanding, synthetic access to the highly oxidized enmein-type ent-kauranoids still presents considerable challenges to synthetic chemists. Here, we report the enantioselective total syntheses of C-19 oxygenated enmein-type ent-kauranoids, including (-)-macrocalyxoformins A and B and (-)-ludongnin C, along with discussion and study of synthetic strategies. The enabling feature in our synthesis is a devised Ni-catalyzed decarboxylative cyclization/radical-polar crossover/C-acylation cascade that forges a THF ring concomitantly with the ß-keto ester group. Mechanistic studies reveal that the C-acylation process in this cascade reaction is achieved through a carboxylation followed by an in situ esterification. Biological evaluation of these synthetic natural products reveals the indispensable role of the ketone on the D ring in their anti-tumor efficacy.

Effect of Bakri balloon tamponade combined with different suture methods on preventing postpartum hemorrhage in women with pregnancy-induced hypertension undergoing cesarean delivery.

OBJECTIVE: To investigate the effect of Bakri balloon tamponade (BBT) combined with different suture methods on preventing postpartum hemorrhage in women with pregnancy-induced hypertension (PIH) undergoing cesarean delivery (CD). METHODS: This randomized, double-blind, controlled trial was conducted at The First Affiliated Hospital of Xingtai Medical College from October 2020 to June 2023. Patients with PIH who had persistent bleeding after CD and were unresponsive to uterine contractions, sutures, or uterine disconnection procedures were eligible participants. Eligible participants were randomly assigned to control and study groups, with 50 patients in each group. The control group used BBT combined with B-lynch uterine compression sutures, while the study group used BBT combined with modified Hayman suture. Intraoperative and postoperative bleeding and changes in vital signs were compared between the 2 groups. Moreover, changes in inflammation levels, coagulation function, and sex hormone levels were compared between the 2 groups before and after surgery. RESULTS: A total of 122 patients with persistent bleeding after CD were recruited, of whom 22 were excluded (16 cases of uterine contractions and/or local uterine myometrial sutures for hemostasis, 4 cases of preoperative uterine artery embolization, and 2 cases of uterine malformations). The intraoperative blood loss, postoperative blood loss at 2 hours, postoperative blood loss at 24 hours, and decrease in red blood cell and hemoglobin in the study group were significantly lower than those in the control group (P < .05). After surgery, the levels of inflammation, coagulation function, and sex hormone in both groups improved compared to before surgery, and the study group was significantly better than the control group (P < .05). In addition, the incidence of postoperative adverse events in the study group was significantly lower than that in the control group (P < .05). CONCLUSIONS: The hemostatic effect of BBT combined with B-lynch uterine compression sutures is comparable to that of BBT combined with modified Hayman suture for postpartum hemorrhage in pregnant women with PIH undergoing CD, but the latter has less blood loss, attenuated inflammatory response, reduced impact on coagulation function and ovarian function, and a lower incidence of adverse events.

BART: A transferable liquid chromatography retention time library for bile acids.

Identification of unknown bile acids, especially the distinguishment between isomers, requires retention times of a large number of reference standards, which are often not commercially available. Meanwhile, published retention information cannot be directly transferred across labs due to the differences between liquid chromatography (LC) systems, such as different extra column volume and dwell volume. To improve this situation, a transferrable retention time library for bile acids named BART was developed. BART was composed of isocratic retention models of 272 bile acids and a software tool to predict their gradient retention times on various LC systems. The isocratic retention times of bile acids were acquired on a Waters BEH C18 column with mobile phases of acidic ammonium acetate buffer and acetonitrile, and fit to the quadratic solvent strength model (QSSM). Segmented linear gradient retention times were calculated with holdup time (t0), dwell time (tD) and actual gradient profile corrected using 21 bile acid calibration standards. In addition to the reference system where the isocratic retention times were acquired, this approach has been validated on four other LC-MS systems in four labs with two gradient methods. Average root mean square errors (RMSE) between predicted and experimental retention times were 0.052 and 0.054 min for the two gradients tested, which were 9-fold more accurate than referring to a static retention time library. The library is freely available at https://bafinder.github.io/.

Specific binding of GPR174 by endogenous lysophosphatidylserine leads to high constitutive Gs signaling.

Many orphan G protein-coupled receptors (GPCRs) remain understudied because their endogenous ligands are unknown. Here, we show that a group of class A/rhodopsin-like orphan GPCRs including GPR61, GPR161 and GPR174 increase the cAMP level similarly to fully activated D1 dopamine receptor (D1R). We report cryo-electron microscopy structures of the GPR61‒Gs, GPR161‒Gs and GPR174‒Gs complexes without any exogenous ligands. The GPR174 structure reveals that endogenous lysophosphatidylserine (lysoPS) is copurified. While GPR174 fails to respond to exogenous lysoPS, likely owing to its maximal activation by the endogenous ligand, GPR174 mutants with lower ligand binding affinities can be specifically activated by lysoPS but not other lipids, in a dose-dependent manner. Moreover, GPR174 adopts a non-canonical Gs coupling mode. The structures of GPR161 and GPR61 reveal that the second extracellular loop (ECL2) penetrates into the orthosteric pocket, possibly contributing to constitutive activity. Our work definitively confirms lysoPS as an endogenous GPR174 ligand and suggests that high constitutive activity of some orphan GPCRs could be accounted for by their having naturally abundant ligands.

Integration of semi-empirical MS/MS library with characteristic features for the annotation of novel amino acid-conjugated bile acids.

Recently, amino acids other than glycine and taurine were found to be conjugated with bile acids by the gut microbiome in mouse and human. As potential diagnostic markers for inflammatory bowel disease and farnesoid X receptor agonists, their physiological effects and mechanisms, however, remain to be elucidated. A tool for the rapid and comprehensive annotation of such new metabolites is required. Thus, we developed a semi-empirical MS/MS library for bile acids conjugated with 18 common amino acids, including alanine, arginine, asparagine, aspartate, glutamine, glutamate, histidine, isoleucine, leucine, lysine, methionine, phenylalanine, proline, serine, threonine, tryptophan, tyrosine, and valine. To investigate their fragmentation rules, these amino acids were chemically conjugated with lithocholic acid, deoxycholic acid, and cholic acid, and their accurate-mass MS/MS spectra were acquired. The common fragmentation patterns from the amino acid moieties were combined with 10 general bile acid skeletons to generate a semi-empirical MS/MS library of 180 structures. Software named BAFinder 2.0 was developed to combine the semi-empirical library in negative mode and the characteristic fragments in positive mode for automatic unknown identification. As a proof of concept, this workflow was applied to the LC-MS/MS analysis of the feces of human, beagle dogs, and rats. In total, 171 common amino acid-conjugated bile acids were annotated and 105 of them were confirmed with the retention times of synthesized compounds. To explore other potential bile acid conjugates, user-defined small molecules were in-silico conjugated with bile acids and searched in the fecal dataset. Four novel bile acid conjugates were discovered, including D-Ala-D-Ala, Lys(iso)-Gly, L-2-aminobutyric acid, and ornithine.

Family-based analysis of -675 4G/5G polymorphism in the PAI-1 gene of polycystic ovary syndrome in Chinese population.

Previous studies have shown that 4G/5G polymorphism in promoter region of plasminogen activator inhibitor-1 (PAI-1) gene can affect insulin sensitivity by elevating the level and activity of plasma PAI-1. In order to elucidate the relationship between the polymorphism of PAI-1 gene and polycystic ovary syndrome (PCOS), we used transmission disequilibrium test (TDT) to study the family of PCOS. Eight hundred and fifty-five participants consisting of 285 trios (mother, father and offspring with PCOS) were recruited at the Center of Reproductive Medicine, Shandong University from July 2007 to August 2014. 4G/5G polymorphism of PAI-1 gene was genotyped using direct sequencing protocol and TDT was used to analyse the association between PAI-1 gene and PCOS. Though the 5G allele in PAI-1 gene was overtransmitted in families, no statistical significance existed and there was no association between PAI-1 gene and PCOS, indicating that PAI-1 gene was unlikely to play a major role in the aetiology of PCOS in Chinese population.Impact StatementWhat is already known on this subject? Some studies have shown that 4G/5G polymorphism in promoter region of plasminogen activator inhibitor-1 (PAI-1) gene can affect insulin sensitivity by elevating the level and activity of plasma PAI-1, participating in the formation of insulin resistance (IR).What do the results of this study add? Though the 5G allele in PAI-1 gene was overtransmitted in families, no statistical significance existed and there was no association between PAI-1 gene and polycystic ovary syndrome (PCOS).What are the implications of these findings for clinical practice and/or further research? PAI-1 gene was unlikely to play a major role in the aetiology of PCOS.

Temporary Increased LDL-C in Offspring with Extreme Elevation of Maternal Preconception Estradiol: A Retrospective Cohort Study.

Objective: To investigate the effect of maternal estradiol (E2) elevation on long-term metabolic manifestations in the offspring. Study Design and Setting: This was a retrospective cohort study. Overall, 3690 children conceived by in vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI) between July 2014 and December 2017 were recruited and divided into four groups categorized by maternal E2 quartiles (Q1, <2420; Q2, 2420-3839; Q3, 3839-5599; and Q4, ≥5599 pg/mL). The metabolic profiles were measured during childhood. Linear mixed models were used to evaluate the association between maternal E2 elevation and metabolic phenotypes of the offspring. Results: Lipoprotein cholesterol (LDL-C) was significantly higher in the highest quartile group than in the lowest quartile group during infancy (adjusted mean difference [95% confidence interval, CI]): 0.11 [0.02, 0.20], P = 0.005), but the difference disappeared in the later childhood phase. In children born after fresh embryo transfer, LDL-C showed an increasing trend with the increase in maternal E2 level (adjusted mean difference [95% CI]: Q2 vs Q1, -0.01 [-0.11, 0.08], Q3 vs Q1, 0.06 [-0.04, 0.15], Q4 vs Q1, 0.10 [0, 0.20]). Other metabolic variables were comparable across increasing quartiles of maternal E2 levels. Conclusion: This study demonstrates a temporary increase in LDL-C levels in infants with higher levels of maternal preconception E2 levels. However, the long-term safety of hyperestrogens after ovarian stimulation in the next generation is favorable. The mechanism underlying the transiently increased metabolic dysfunction risk in infants conceived by IVF/ICSI requires investigation in future studies.

Calmodulin Binding Activates Chromobacterium CopC Effector to ADP-Riboxanate Host Apoptotic Caspases.

Blocking host cell death is an important virulence strategy employed by many bacterial pathogens. We recently reported that Shigella flexneri inhibits host pyroptosis by delivering a type III secretion system (T3SS) effector OspC3 that catalyzes a novel arginine ADP-riboxanation modification on caspase-4/11. Here, we investigated the OspC3 homologue CopC from Chromobacterium violaceum, an opportunistic but sometimes deadly bacterial pathogen. CopC bears the same arginine ADP-riboxanase activity as OspC3, but with a different substrate specificity. Through proteomic analysis, we first identified host calmodulin (CaM) as a binding partner of CopC. The analyses additionally revealed that CopC preferably modifies apoptotic caspases including caspase-7, -8 and -9. This results in suppression of both extrinsic and intrinsic apoptosis programs in C. violaceum-infected cells. Biochemical reconstitution showed that CopC requires binding to CaM, specifically in the calcium-free state, to achieve efficient ADP-riboxanation of the caspases. We determined crystal structure of the CaM-CopC-CASP7 ternary complex, which illustrates the caspase recognition mechanism and a unique CaM-binding mode in CopC. Structure-directed mutagenesis validated the functional significance of CaM binding for stimulating CopC modification of its caspase substrates. CopC adopts an ADP-ribosyltransferase-like fold with a unique His-Phe-Glu catalytic triad, featuring two acidic residues critical for site-specific arginine ADP-riboxanation. Our study expands and deepens our understanding of the OspC family of ADP-riboxanase effectors. IMPORTANCE Programmed cell death is a suicidal defense mechanism for eukaryotes to combat pathogen infection. In the evolutionary arms race with the host, bacteria are endowed with ingenious tactics to block host cell death to facilitate their replication. Here, we report that the C. violaceum effector CopC ADP-riboxanates caspase-7/8/9, enabled by interacting with the host factor calmodulin, to block host cell apoptosis, illustrating a unique and sophisticated strategy adopted by the pathogen to counteract host defense.

BAFinder: A Software for Unknown Bile Acid Identification Using Accurate Mass LC-MS/MS in Positive and Negative Modes.

Most LC-MS based bile acid analyses target common bile acids. The identification of unknown bile acids remains challenging in untargeted experiments. Here, a software named BAFinder was developed to improve the identification of unknown bile acids from accurate mass LC-MS/MS data in both the positive and negative ESI modes. A wide variety of bile acid structures were covered in BAFinder, including oxidized bile acids and sugar conjugates that were often ignored. The annotation of unknown bile acids was based on a thorough investigation of MS/MS fragmentation patterns of 84 bile acid reference standards in both modes. Specifically, BAFinder took the peak alignment result and MS/MS spectra, grouped candidate features in positive and negative modes, searched their representative MS/MS spectra against a MS/MS library, and used characteristic product ions and neutral losses to annotate bile acids not covered in the library. Finally, the number of hydroxyl groups and double bonds, conjugation, and isomer information of bile acids were reported with four different levels of annotation confidence. The use of BAFinder was demonstrated through successful application to the analysis of human plasma and urine samples, in which a total of 112 and 244 bile acids were annotated and 75 and 111 of them were confirmed with standards or synthesized compounds, respectively. The software is freely available at https://bafinder.github.io/.

Cholesterol inhibits TCR signaling by directly restricting TCR-CD3 core tunnel motility.

Cholesterol molecules specifically bind to the resting αßTCR to inhibit cytoplasmic CD3ζ ITAM phosphorylation through sequestering the TCR-CD3 complex in an inactive conformation. The mechanisms of cholesterol-mediated inhibition of TCR-CD3 and its activation remain unclear. Here, we present cryoelectron microscopy structures of cholesterol- and cholesterol sulfate (CS)-inhibited TCR-CD3 complexes and an auto-active TCR-CD3 variant. The structures reveal that cholesterol molecules act like a latch to lock CD3ζ into an inactive conformation in the membrane. Mutations impairing binding of cholesterol molecules to the tunnel result in the movement of the proximal C terminus of the CD3ζ transmembrane helix, thereby activating the TCR-CD3 complex in human cells. Together, our data reveal the structural basis of TCR inhibition by cholesterol, illustrate how the cholesterol-binding tunnel is allosterically coupled to TCR triggering, and lay a foundation for the development of immunotherapies through directly targeting the TCR-CD3 complex.

Iodide promotes bisphenol A (BPA) halogenation during chlorination: Evidence from 30 X-BPAs (X = Cl, Br, and I).

As a well known endocrine-disrupting and model chemical, bisphenol A (BPA) may pose a serious threat to human health, since it and its disinfection by-products (DBPs) have been detected in drinking water, urine, human colostrum, adipose tissue, and placenta samples. Although chlorinated BPAs (Cl-BPAs) and iodinated BPAs (I-BPAs) have been well studied, brominated BPAs (Br-BPAs), and mixed halogenated DBPs like bromo-iodo-BPAs (Br-I-BPAs), and bromo-chloro-iodo-BPAs (Cl-Br-I-BPAs) are less well understood. Notably, the role of iodide (I-) during chlorination is not well understood, since the studies of the I-DBPs mainly focus on their genotoxicity and cytotoxicity. To understand the formation mechanisms of halogenated bisphenol A (HBPs) during chlorination with bromide (Br-) and/or I-, and the role of I- during chlorination, three set of reactions were performed in the laboratory ("BPA + chlorine + Br-", "BPA + chlorine + I-" and "BPA + chlorine + Br- +I-" assigned as group A, B and C respectively). Thirty HBPs were identified and 18 of them were never reported before. I- increases the transformation rate of BPA into HBPs as I-BPAs act as intermediate HBPs during chlorination that easily react with HClO/ClO- and HBrO/BrO- to form Cl-BPAs and Br-BPAs. HIO/IO- showed higher reactivity towards BPA and HBPs than that of HBrO/BrO- and HClO/ClO-. The recycling of I- was observed in the reactions of "BPA + chlorine + I-" and "BPA + chlorine + Br- +I-", which may explain why I- can induce BPA to transform into HBPs and suggests that I- may act as a catalyst during the BPA chlorination reactions. The reaction pathways are proposed which present the reactions of BPA and HBPs with HClO/ClO-, HBrO/BrO-, and HIO/IO-, as well as the recycling of I-. This study describes the potential DBP formation and transformation mechanisms of BPA and its 16 alternatives, as well as the role of I- on the transformation of phenol compounds during chlorination.

Colonization characteristics of bacterial communities on plastic debris: The localization of immigrant bacterial communities.

The unique characteristics of bacterial communities on plastic debris and microplastics in the environment have been widely studied in recent years. However, due to the randomness of sampling, it is hard to identify whether the unique characteristics of bacterial communities on plastic debris is due to the plastics as substrate itself, or the accumulation and transportation by plastics. Therefore, the ecological effects of bacterial communities on plastic debris, including the species invasion, are still not clear. To investigate such issue, we took the Haihe Estuary (Tianjin, China) as an example, and designed a strategy to sample and redeploy randomly collected environmental plastic debris for 6 weeks, thus the variation of bacterial communities on plastic debris could be assessed. At the same time, commercial experimental plastic debris was used as the control group to monitor the growth of local bacterial communities on plastics in the cultivation environment. Our study discussed the bacterial communities on the environmental plastic debris from three aspects, including colonization characteristics, taxonomic analysis and molecular metabolism estimation. We found that the bacterial communities on environmental plastic debris tended to show local characteristics, which were less affected by their original characteristics. Therefore, the results reminded us that the ecological risks of bacterial communities on plastics, which were brought by the transportation of plastic debris in the environment, may not be as serious as it was expected previously.

Visual outcomes and corneal biomechanics after V4c implantable collamer lens implantation in subclinical keratoconus.

PURPOSE: To quantitatively evaluate the safety, efficacy, stability, predictability, and corneal biomechanical parameters after V4c implantable collamer lens (ICL) implantation in subclinical keratoconus. SETTING: Xi'an AIER Eye Hospital, Xi'an, China. DESIGN: Retrospective case series. METHODS: Patients undergoing V4c ICL/toric ICL implantation were examined. Scheimpflug tomography (Pentacam) was used to measure the Belin-Ambrosio enhanced ectasia total deviation index. Dynamic Scheimpflug biomechanical analysis (CorVis ST) was used to measure the corneal biomechanical parameters and Corvis Biomechanical Index. The Tomographic and Biomechanical Index was measured by combined Pentacam with CorVis ST. Uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), refraction, and adverse effects were also investigated. RESULTS: A total of 60 eyes of 60 patients (mean age ± SD, 27.21 ± 7.24 years) were included. The mean preoperative UDVA and CDVA were 1.08 ± 0.25 and 0.12 ± 0.04 logarithm of the minimum angle of resolution (logMAR) (20/230 and 20/28 Snellen VA), respectively. After 2 years, the mean postoperative UDVA and CDVA were 0.01 ± 0.06 and -0.05 ± 0.03 logMAR (20/20 and 20/18 Snellen VA), respectively. The mean difference between the intended and achieved spherical equivalent (SE) was -0.08 ± 0.47 diopter (D), and the SE was within ±1.00 D of the intended correction in 57 eyes (95%), and 58 eyes (97%) had astigmatism less than 0.50 D. The refractive results were stable 2 years postoperatively, and the corneal biomechanical parameters returned to their preoperative levels at 3 months. CONCLUSIONS: The V4c ICL/toric ICL in subclinical keratoconus offered predictable correction of SE refractive error. Refractive results and corneal biomechanics were stable at the 2-year follow-up.

Genetic polymorphisms of melatonin receptors 1A and 1B may result in disordered lipid metabolism in obese patients with polycystic ovary syndrome.

Polycystic ovary syndrome (PCOS) is a condition in which a woman's levels of the sex hormones (estrogen and progesterone) are out of balance, leading to the growth of ovarian cysts. PCOS can affect the menstrual cycle, fertility, cardiac function and even appearance of women. Therefore, we aimed to explore the genetic polymorphism of the melatonin receptors 1A and 1B in obese patients with PCOS to identify a new theoretical basis for its treatment. Patients presenting with PCOS (n=359) were enrolled and classified into an obese OB­PCOS group [body mass index (BMI) of PCOS patients ≥25 kg/m2] or a nonobese NOB­PCOS group, and 215 oviduct infertile patients who experienced normal ovulation were used as the control group. All baseline characteristics, endocrine hormone levels, lipid and glucose metabolism, and insulin indices were measured. The genotypes of rs2119882 within the MTNR1A gene and of rs10830963 within the MTNR1B gene were determined by PCR­RFLP; the genotype frequency and the difference in the distribution of allele frequency were compared. For rs2119882, C allele carriers who were not diagnosed with PCOS had an increased risk of developing PCOS, and C allele carriers with PCOS had an increased risk of developing OB­PCOS. For rs10830963, G allele carriers who were not diagnosed with PCOS had an increased risk of developing PCOS. The TT genotype in rs2119882 and the CC genotype in rs10830963 were protective factors for OB­PCOS, and increased levels of LH, testosterone, and estradiol and abnormal menstruation were key risk factors for PCOS. Furthermore, the TT genotype at the rs2119882 site was the key protective factor for OB­PCOS patients. Our study found that MTNR1A rs2119882 and MTNR1B rs10830963 could increase the risk for PCOS and cause glycolipid metabolism disorder in PCOS patients.

A cross-sectional study among survivors of the 2008 Sichuan earthquake: prevalence and risk factors of posttraumatic stress disorder.

OBJECTIVE: The objective of this study is to estimate the prevalence of probable posttraumatic stress disorder (PTSD), explore the related risk factors among Sichuan earthquake survivors in different counties and compare the findings in our study to others. METHOD: A cross-sectional sample survey was conducted to collect data in heavily (n=367) and moderately damaged counties (n=337). We used the PTSD Check List-Civilian Version (PCL-C), which consists of 17 items corresponding to each symptom of Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition. RESULTS: The prevalence of probable PTSD in heavily damaged counties (48.2%) was higher than that in moderately damaged counties (14.5%). Many associated risk factors were identified in the cross-sectional study. CONCLUSION: Female, Han nationality, low monthly income, fear during earthquake and low social support in the past year were significant risk factors in heavily damaged counties, while the probable PTSD in moderately damaged counties was related to female, youth, fear during earthquake and low social support.

Posttraumatic stress disorder among survivors of the Wenchuan earthquake 1 year after: prevalence and risk factors.

Exposure to earthquakes has been associated with psychological distress in particular, the development of posttraumatic stress disorder (PTSD). The aims of this study are to estimate the prevalence of PTSD, explore the associated risk factors among survivors 1 year after the Wenchuan earthquake in China, and compare the findings in our study to other disasters. Cross-sectional sample survey was conducted to collect data in severely affected counties. We use the PTSD Check List-Civilian Version, which consists of 17 items corresponding to each symptom in Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition PTSD criteria B, C, and D. The prevalence estimates of probable PTSD in our sample ranged from 21.5% (based on Check List-Civilian Version score of 50 or higher) to 40.1% (based on Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition criteria). The prevalence of PTSD was high, compared with rates of PTSD in previous studies. Low social support, feeling fear during the earthquake, female, young people, Han nationality, low monthly income, and low educational level were risk factors significantly related to the development of PTSD. Postdisaster mental health recovery interventions including early identification, ongoing monitoring, and sustained psychosocial support are required for the high-risk population with PTSD. Existing rural and urban health care services should be convenient for people, and special measures need to be designed, such as home visits and mobile clinics.