Modulation of mercaptopurine intestinal toxicity and pharmacokinetics by gut microbiota.

The interaction between the gut microbiota and mercaptopurine (6-MP), a crucial drug used in pediatric acute lymphoblastic leukemia (ALL) treatment, has not been extensively studied. Here we reveal the significant perturbation of gut microbiota after 2-week 6-MP treatment in beagles and mice followed by the functional prediction that showed impairment of SCFAs production and altered amino acid synthesis. And the targeted metabolomics in plasma also showed changes in amino acids. Additionally, targeted metabolomics analysis of feces showed changes in amino acids and SCFAs. Furthermore, ablating the intestinal microbiota by broad-spectrum antibiotics exacerbated the imbalance of amino acids, particularly leading to a significant decrease in the concentration of S-adenosylmethionine (SAM). Importantly, the depletion of gut microbiota worsened the damage of small intestine caused by 6-MP, resulting in increased intestinal permeability. Considering the relationship between toxicity and 6-MP metabolites, we conducted a pharmacokinetic study in pseudo germ-free rats to confirm that gut microbiota depletion altered the methylation metabolites of 6-MP. Specifically, the concentration of MeTINs, a secondary methylation metabolite, showed a negative correlation with SAM, the pivotal methyl donor. Additionally, we observed a strong correlation between Alistipes and SAM levels in both feces and plasma. In conclusion, our study demonstrates that 6-MP disrupts the gut microbiota, and depleting the gut microbiota exacerbates 6-MP-induced intestinal toxicity. Moreover, SAM derived from microbiota plays a crucial role in influencing plasma SAM and the methylation of 6-MP. These findings underscore the importance of comprehending the role of the gut microbiota in 6-MP metabolism and toxicity.

[Research advances in nucleic acid drugs developed based on circular RNAs].

The development and clinical application of nucleic acid drugs has been a trendy field. One of the notable examples is mRNA vaccines, which have been used in the fighting against SARS-CoV-2. With short development cycles and mature preparation processes, mRNA vaccines demonstrate advantages in the global supply and in response to virus mutations. Circular RNAs (circRNAs) are a group of nucleic acid molecules with more stable structure, longer half-life, and weaker immunogenicity than mRNAs. Studies have proven that circRNAs can efficiently express protein products, indicating their potential in drug development. Despite extensive studies on the biogenesis and biological functions of circRNAs, there is limited research on developing nucleic acid drugs based on circRNAs. This article provides an overview of circRNAs, including their basic information, synthesis routes, and mechanisms, and discusses the future development directions of this field, hoping to provide inspiration for the research and development of drugs based on circRNAs.

Sulfonate derivatives bearing an amide unit: design, synthesis and biological activity studies.

Pest disasters which occurs on crops is a serious problem that not only cause crop yield loss or even crop failure but can also spread a number of plant diseases.Sulfonate derivatives have been widely used in insecticide and fungicide research in recent years. On this basis, a series of sulfonate derivatives bearing an amide unit are synthesized and the biological activities are evaluated. The bioassay results showed that compounds A8, A13, A16, B1, B3, B4, B5, B10, B12 - 20, C3, C5, C9, C10, C14, C15, C17 and C19 showed 100% activity at a concentration of 500 µg/mL against the Plutella xylostella (P. xylostella). Among them, B15 which contains a thiadiazole sulfonate structure still shows 100% activity at 50 µg/mL concentration against P. xylostella and had the lowest median lethal concentration (LC50) (7.61 µg/mL) among the target compounds. Further mechanism studies are conducted on compounds with better insecticidal activity. Molecular docking results shows that B15 formed hydrophobic interactions π-π and hydrogen bonds with the indole ring of Trp532 and the carboxyl group of Asp384, respectively, with similar interaction distances or bond lengths as those of diflubenzuron. Moreover, chitinase inhibition assays are performed to further demonstrate its mode of action. In addition, the anti-bacterial activity of the series of compounds is also tested and the results showed that the series of compounds has moderate biological activity against Xanthomonas oryzae pv. oryzae (Xoo) and Xanthomonas oryzae pv. oryzicola (Xoc), with inhibition rates of 91%, 92% and 92%, 88% at the concentration of 100 µg/mL, respectively. Our study indicates that B15 can be used as a novel insecticide for crop protection.

Synthesis, Structural Characterization, and Biological Activities of 1,3,4- Thiadiazole Derivatives Containing Sulfonylpiperazine Structures.

To develop novel bacterial biofilm inhibiting agents, a series of 1,3,4-thiadiazole derivatives containing sulfonylpiperazine structures were designed, synthesized, and characterized using 1H nuclear magnetic resonance (1H NMR), 13C nuclear magnetic resonance (13C NMR), and high-resolution mass spectrometry. Meanwhile, their biological activities were evaluated, and the ensuing structure-activity relationships were discussed. The bioassay results showed the substantial antimicrobial efficacy exhibited by most of the compounds. Among them, compound A24 demonstrated a strong efficacy with an EC50 value of 7.8 µg/mL in vitro against the Xanthomonas oryzae pv. oryzicola (Xoc) pathogen, surpassing commercial agents thiodiazole copper (31.8 µg/mL) and bismerthiazol (43.3 µg/mL). Mechanistic investigations into its anti-Xoc properties revealed that compound A24 operates by increasing the permeability of bacterial cell membranes, inhibiting biofilm formation and cell motility, and inducing morphological changes in bacterial cells. Importantly, in vivo tests showed its excellent protective and curative effects on rice bacterial leaf streak. Besides, molecular docking showed that the hydrophobic effect and hydrogen-bond interactions are key factors between the binding of A24 and AvrRxo1-ORF1. Therefore, these results suggest the utilization of 1,3,4-thiadiazole derivatives containing sulfonylpiperazine structures as a bacterial biofilm inhibiting agent, warranting further exploration in the realm of agrochemical development.

Gut commensal Christensenella minuta modulates host metabolism via acylated secondary bile acids.

A strong correlation between gut microbes and host health has been observed in numerous gut metagenomic cohort studies. However, the underlying mechanisms governing host-microbe interactions in the gut remain largely unknown. Here we report that the gut commensal Christensenella minuta modulates host metabolism by generating a previously undescribed class of secondary bile acids with 3-O-acylation substitution that inhibit the intestinal farnesoid X receptor. Administration of C. minuta alleviated features of metabolic disease in high fat diet-induced obese mice associated with a significant increase in these acylated bile acids, which we refer to as 3-O-acyl-cholic acids. Specific knockout of intestinal farnesoid X receptor in mice counteracted the beneficial effects observed in their wild-type counterparts. Finally, we showed that 3-O-acyl-CAs were prevalent in healthy humans but significantly depleted in patients with type 2 diabetes. Our findings indicate a role for C. minuta and acylated bile acids in metabolic diseases.

Efficacy and safety evaluations of adalimumab biosimilars in the treatment of psoriasis.

PURPOSE: We aimed to systematically evaluate the efficacy and safety of adalimumab biosimilar agents in the treatment of moderate-to-severe plaque psoriasis, in order to provide evidence-based reference data for clinical medicine. MATERIALS AND METHODS: Five databases were searched by electronic retrieval: PubMed, Embase, Cochrane Library, WanFang and CNKI (China National Knowledge Internet). The retrieval period was from the establishment of each database up to April 2022. Randomized controlled trials (RCTs) on adalimumab biosimilar agents compared with their reference agents in the treatment of moderate-to-serve plague psoriasis were included. A meta-analysis using RevMan software was applied to 8 RCTs involving 2589 patients. RESULTS: After 16 weeks of medication, there was no significant difference in the response rates of adalimumab biosimilar agents and their reference agents defined as a decrease in the Psoriasis Area and Severity Index (PASI) of ≥75% (PASI 75) (p > 0.05), or in the PASI 50, PASI 90 and PASI 100 measures (p > 0.05). After 16 weeks and 24 weeks of medication, there was no significant difference in the incidence rate of serious adverse events (SAEs) between adalimumab biosimilar agents and their reference agents (p > 0.05). After 16 weeks, 24 weeks and 51 weeks of medication, there was no significant difference in withdrawal rate due to SAEs, treatment-emergent adverse events and adverse events of special interest between adalimumab biosimilar agents and their reference agents (p > 0.05). CONCLUSION: These findings suggest that biosimilar agents of adalimumab have an overall efficacy and safety profile for psoriasis comparable to those of their reference agents.

Panax quinquefolius saponins combined with dual antiplatelet therapy enhanced platelet inhibition with alleviated gastric injury via regulating eicosanoids metabolism.

BACKGROUND: Panax quinquefolius saponin (PQS) was shown beneficial against platelet adhesion and for gastroprotection. This study aimed to investigate the integrated efficacy of PQS with dual antiplatelet therapy (DAPT) on platelet aggregation, myocardial infarction (MI) expansion and gastric injury in a rat model of acute MI (AMI) and to explore the mechanism regarding arachidonic acid (AA)-derived eicosanoids metabolism. METHODS: Wistar rats were subjected to left coronary artery occlusion to induce AMI model followed by treatment with DAPT, PQS or the combined therapy. Platelet aggregation was measured by light transmission aggregometry. Infarct size, myocardial histopathology was evaluated by TTC and H&E staining, respectively. Gastric mucosal injury was examined by scanning electron microscope (SEM). A comprehensive eicosanoids profile in plasma and gastric mucosa was characterized by liquid chromatography-mass spectrometer-based lipidomic analysis. RESULTS: PQS+DAPT further decreased platelet aggregation, lessened infarction and attenuated cardiac injury compared with DAPT. Plasma lipidomic analysis revealed significantly increased synthesis of epoxyeicosatrienoic acid (EET) and prostaglandin (PG) I2 (potent inhibitors for platelet adhesion and aggregation) while markedly decreased thromboxane (TX) A2 (an agonist for platelet activation and thrombosis) by PQS+DAPT, relative to DAPT. DAPT induced overt gastric mucosal damage, which was attenuated by PQS co-administration. Mucosal gastroprotective PGs (PGE2, PGD2 and PGI2) were consistently increased after supplementation of PQS+DAPT. CONCLUSIONS: Collectively, PQS+DAPT showed synergistic effect in platelet inhibition with ameliorated MI expansion partially through upregulation of AA/EET and AA/PGI2 synthesis while suppression of AA/TXA2 metabolism. PQS attenuated DAPT-induced gastric injury, which was mechanistically linked to increased mucosal PG production.

Rhodium-Catalyzed Regio- and Enantioselective Allylic Sulfonylation from Sulfonyl Hydrazides.

A highly regio- and enantioselective allylic sulfonylation has been developed with rhodium and bisoxazolinephosphine (NPN*) ligands from racemic branched allylic carbonates and readily available sulfonyl hydrazides under neutral conditions. Branch-selective allylic sulfones with a >20:1 branch:linear ratio and >99% ee could be synthesized in ≤96% yield. Both Z and E linear allylic carbonates could also be converted into the same chiral branched allylic sulfones with high regio- and enantioselectivities.

Diversity of endosymbionts in camellia spiny whitefly, Aleurocanthus camelliae (Hemiptera: Aleyrodidae), estimated by 16S rRNA analysis and their biological implications.

Camellia spiny whitefly, Aleurocanthus camelliae (Hemiptera: Aleyrodidae), is a major pest in tea, which poses a serious threat to tea production. Similar to many insects, various bacterial symbioses inside A. camelliae may participate in the reproduction, metabolism, and detoxification of the host. However, few reports included research on the microbial composition and influence on A. camelliae growth. We first applied high-throughput sequencing of the V4 region in the 16S rRNA of symbiotic bacteria to study its component and effect on the biological trait of A. camelliae by comparing it with the antibiotic treatment group. The population parameters, survival rate, and fecundity rate of A. camelliae were also analyzed using the age-stage two-sex life table. Our results demonstrated that phylum Proteobacteria (higher than 96.15%) dominated the whole life cycle of A. camelliae. It unveiled the presence of Candidatus Portiera (primary endosymbiont) (67.15-73.33%), Arsenophonus (5.58-22.89%), Wolbachia (4.53-11.58%), Rickettsia (0.75-2.59%), and Pseudomonas (0.99-1.88%) genus. Antibiotic treatment caused a significant decrease in the endosymbiont, which negatively affected the host's biological properties and life process. For example, 1.5% rifampicin treatment caused a longer preadult stage in the offspring generation (55.92 d) compared to the control (49.75d) and a lower survival rate (0.36) than the control (0.60). The decreased intrinsic rate of increase (r), net reproductive rate (R 0), and prolonged mean generation time (T) were signs of all disadvantageous effects associated with symbiotic reduction. Our findings confirmed the composition and richness of symbiotic bacteria in larva and adult of A. camelliae by an Illumina NovaSeq 6000 analysis and their influence on the development of the host by demographic research. Together, the results suggested that symbiotic bacteria play an important role in manipulating the biological development of their hosts, which might help us for developing new pest control agents and technologies for better management of A. camelliae.

Design, Synthesis and Bioactivity of Novel Pyrimidine Sulfonate Esters Containing Thioether Moiety.

Pesticides play an important role in crop disease and pest control. However, their irrational use leads to the emergence of drug resistance. Therefore, it is necessary to search for new pesticide-lead compounds with new structures. We designed and synthesized 33 novel pyrimidine derivatives containing sulfonate groups and evaluated their antibacterial and insecticidal activities. Results: Most of the synthesized compounds showed good antibacterial activity against Xanthomonas oryzae pv. Oryzae (Xoo), Xanthomonas axonopodis pv. Citri (Xac), Pseudomonas syringae pv. actinidiae (Psa) and Ralstonia solanacearum (Rs), and certain insecticidal activity. A5, A31 and A33 showed strong antibacterial activity against Xoo, with EC50 values of 4.24, 6.77 and 9.35 µg/mL, respectively. Compounds A1, A3, A5 and A33 showed remarkable activity against Xac (EC50 was 79.02, 82.28, 70.80 and 44.11 µg/mL, respectively). In addition, A5 could significantly improve the defense enzyme (superoxide dismutase, peroxidase, phenylalanine ammonia-lyase and catalase) activity of plants against pathogens and thus improve the disease resistance of plants. Moreover, a few compounds also showed good insecticidal activity against Plutella xylostella and Myzus persicae. The results of this study provide insight into the development of new broad-spectrum pesticides.

Regio- and Enantioselective Allylic Cyanomethylation by Synergistic Rhodium and Silane Catalysis.

Rh/silane-cocatalyzed regio- and enantioselctive allylic cyanomethylation with inert acetonitrile directly has been developed. Addition of a catalytic amount neutral silane reagent as an acetonitrile anion carrier is essential for the success of this reaction. The synthesis of mono- and bis-allylation products can be switched by adjusting the size of substituents on the silane, ligands, and temperature. Chiral homoallylic nitriles could be synthesized in above 20:1 branch/linear ratio, up to 98% yield and >99% ee.

Characteristics of hypertension in the last 16 years in high prevalence region of China and the attribute ratios for cardiovascular mortality.

BACKGROUND: Tianjin is one of the cities with the highest prevalence of hypertension in China and one of the first regions to develop community management of hypertension. Our aim was to analyze the characteristics of hypertension in the last 16 years, and estimate the population attributable fraction for cardiovascular mortality in Tianjin, China. METHODS: We compared the epidemiological characteristics of hypertension between 2002 and 2018 by analyzing data from the National Nutrition and Chronic Disease Risk Factor Survey. Subsequently, we obtained the cause-specific mortality in the same year from the Tianjin All Cause of Death Registration System (CDRS), and the population attributable fraction was used to estimate the annual cardiovascular disease (CVD) deaths caused by hypertension. RESULTS: In 2002 and 2018, the crude prevalence, awareness, treatment rate in diagnosed, control rate in treated, and overall control rate of hypertension were 36.6% and 39.8%, 36.0% and 51.9%, 76.0% and 90.1%, 17.4% and 38.3%, 4.8% and 17.9%, respectively (P < 0.05). The mean SBP for males between the ages of 25 and 50 was significantly higher in 2018 than in 2002. The number of CVD deaths attributed to hypertension was 13.8 thousand in 2002 (account for 59.1% of total CVD deaths), and increased to 21.7 thousand in 2018 (account for 58.8% of total CVD deaths). The population attributable fraction have increased in the age groups of 25-44 and 75 and above, and decreased in the age group of 45-74 from 2002 to 2018. CONCLUSIONS: Compare to 2002, the proportion of CVD deaths attributed to hypertension remains high, particularly among younger and older people, despite a very significant increase in treatment and control rates for hypertension in 2018.

MESSENGER Observations of Planetary Ion Enhancements at Mercury's Northern Magnetospheric Cusp During Flux Transfer Event Showers.

At Mercury, several processes can release ions and neutrals out of the planet's surface. Here we present enhancements of planetary ions (Na+-group ions) in Mercury's northern magnetospheric cusp during flux transfer event (FTE) "showers." FTE showers are intervals of intense dayside magnetopause reconnection, during which FTEs are observed in quick succession, that is, only separated by a few seconds. This study identifies 1953 FTE shower intervals and 1795 Non-FTE shower intervals. During the shower intervals, this study shows that the FTEs form a solar wind entry layer equatorward of the northern magnetospheric cusp. In this entry layer, solar wind ions are accelerated and move downward (i.e., planetward) toward the cusp, which sputter upward-moving planetary ions with a particle flux of 1 × 1011 m-2 s-1 within 1 min. The precipitation rate is estimated to increase by an order of magnitude during FTE showers, to 2 × 1025 s-1, and the neutral density of the exosphere could vary by >10% in response to this FTE-driven sputtering. Such rapid large-scale variations driven by dayside reconnection may explain the minute-to-minute changes in Mercury's exosphere, especially on the high latitudes, observed by ground-based telescopes on Earth. Our MESSENGER in situ observation of enhanced planetary ions in the entry layer likely corresponds to an escape channel for Mercury's planetary ions. Comprehensive, future multipoint measurements made by BepiColombo will greatly enhance our understanding of the processes contributing to Mercury's dynamic exosphere and magnetosphere.

Facile Benzylic Alkylation of Arenes with Alcohols by Catalysis with Spirocyclic NHC IrIII Pincer Complex.

A facile benzylic alkylation of indenes and other arenes was developed from readily available primary and secondary alcohols using our newly investigated CCC pincer IrIII catalyst (SNIr-H). Excellent regioselectivity and yield (89 %) of the C3-alkylated indenes were obtained. Additionally, the challenging sp2 C-alkylation was readily accomplished. This method could be utilized for the synthesis of the analogs of a histamine H1 receptor antagonist and the functional material template molecule, indeno[2,1-a]indene. A hemilabile IrIII -dihydride intermediate was proposed based on control experiments and previous density functional theory (DFT) calculations for the borrowing hydrogen mechanism and is key to the success of this IrIII catalyst in the reduction of unactivated multi-substituted olefin intermediates.

Lactiplantibacillus plantarum P9 improved gut microbial metabolites and alleviated inflammatory response in pesticide exposure cohorts.

Multiple pesticide residue accumulations increase the probability of chronic metabolic diseases in humans. Thus, we applied multi-omics techniques to reveal how the gut microbiome responded to pesticide exposure. Then, we explored how probiotic Lactiplantibacillus plantarum P9 (P9) consumption impacted the gut microbiota and immune factors after high pesticide exposure. Multi-omics results indicated frequent exposure to pesticides did not alter the composition of the intestinal microbiota, but it did increase the abundance of Lipopolysaccharide in the gut, which might contribute to chronic inflammation. Supplementation with P9 maintained the homeostasis of the gut microbiota and reduced the abundance of pathogens in the high pesticide-exposed subjects. By detecting metabolites, we observed uridine and 5-oxoproline concentrations increased significantly after P9 consumption. Furthermore, P9 alleviated immune factors disorder and promoted pesticide residue excretion. Our findings provide new insights into the application of probiotics for pesticide detoxification, and suggest probiotics as daily supplements for pesticide exposure prevention.

Rh-Catalyzed Regio- and Enantioselective Allylic Phosphinylation.

Transition-metal-catalyzed branched and enantioselective allylic substitution of monosubstituted precursors with carbon, nitrogen, oxygen, sulfur, and fluoride nucleophiles has been well-established. However, such a selective carbon-phosphorus bond formation has not been realized probably due to the catalyst deactivation by the strong coordinating nature of phosphinylating reagents. Herein, we report a Rh-catalyzed highly regio- and enantioselective synthesis of allylic phosphine oxides in the presence of a chiral bisoxazoline-phosphine ligand. The application of α-hydroxylalkylphosphine oxides to keep the low concentration of the secondary phosphine oxides is essential for the high yields. The addition of diphenyl phosphoric acid was found to not only activate allylic alcohols but also accelerate the carbon-phosphorus bond formation.

Combined berberine and probiotic treatment as an effective regimen for improving postprandial hyperlipidemia in type 2 diabetes patients: a double blinded placebo controlled randomized study.

Non-fasting lipidemia (nFL), mainly contributed by postprandial lipidemia (PL), has recently been recognized as an important cardiovascular disease (CVD) risk as fasting lipidemia (FL). PL serves as a common feature of dyslipidemia in Type 2 Diabetes (T2D), albeit effective therapies targeting on PL were limited. In this study, we aimed to evaluate whether the therapy combining probiotics (Prob) and berberine (BBR), a proven antidiabetic and hypolipidemic regimen via altering gut microbiome, could effectively reduce PL in T2D and to explore the underlying mechanism. Blood PL (120 min after taking 100 g standard carbohydrate meal) was examined in 365 participants with T2D from the Probiotics and BBR on the Efficacy and Change of Gut Microbiota in Patients with Newly Diagnosed Type 2 Diabetes (PREMOTE study), a random, placebo-controlled, and multicenter clinical trial. Prob+BBR was superior to BBR or Prob alone in improving postprandial total cholesterol (pTC) and low-density lipoprotein cholesterol (pLDLc) levels with decrement of multiple species of postprandial lipidomic metabolites after 3 months follow-up. This effect was linked to the changes of fecal Bifidobacterium breve level responding to BBR alone or Prob+BBR treatment. Four fadD genes encoding long-chain acyl-CoA synthetase were identified in the genome of this B. breve strain, and transcriptionally activated by BBR. In vitro BBR treatment further decreased the concentration of FFA in the culture medium of B. breve compared to vehicle. Thus, the activation of fadD by BBR could enhance FFA import and mobilization in B. breve and diliminish the intraluminal lipids for absorption to mediate the effect of Prob+BBR on PL. Our study confirmed that BBR and Prob (B. breve) could exert a synergistic hypolipidemic effect on PL, acting as a gut lipid sink to achieve better lipidemia and CVD risk control in T2D.

LIMD2 is a Prognostic and Predictive Marker in Patients With Esophageal Cancer Based on a ceRNA Network Analysis.

Globally, esophageal cancer (ECA) is the seventh most common cancer and sixth most common cause of cancer-associated mortality. However, there are no reliable prognostic and predictive molecular markers for ECA; in addition, the pathogenesis of ECA is not fully elucidated. The expressions of circular RNAs (circRNAs), microRNAs (miRNAs), and messenger RNAs (mRNAs) of ECA and control groups were obtained from the RNA-sequencing (RNA-seq) data of our hospital, the Gene Expression Omnibus (GEO), and The Cancer Genome Atlas (TCGA) datasets. Analyses of differentially expressed genes, the circRNA-miRNA-mRNA-competing endogenous RNA (ceRNA) network, and functional/pathway enrichment were conducted. The key targets in the ceRNA network that showed significant results in survival Cox regression analyses were selected. Furthermore, analyses of immune infiltration and autophagy genes related to the key targets were performed. Seven circRNAs, 22 miRNAs, and 34 mRNAs were identified as vital genes in ECA; the nuclear factor-κ-gene binding (NF-κB) and phosphatidylinositol-3 kinase/protein kinase B (PI3K-Akt) signaling were identified as the most enriched pathways. In addition, the LIM domain containing 2 (LIMD2) was an independent predictor of prognosis in ECA patients and closely associated with immunity and autophagy. Moreover, quantitative reverse-transcription polymerase chain reaction (qRT-PCR) revealed significant upregulation of LIMD2 expression in ECA tissues. ECA may be closely correlated with NF-κB and PI3K/Akt signaling. In addition, LIMD2 could be a potential prognostic and predictive marker of ECA.

[Quantitative analysis of nine types of virus-like particles in human papilloma virus bulk by size-exclusion chromatography].

Cervical cancer is the fourth most common cancer among women. Human papilloma virus (HPV) is the most common cause of cervical cancer which accounts for 5% of all human cancers and results in about 528000 cases and 266000 deaths every year. HPV vaccines are considered the most effective strategy for the prevention of HPV infection and cervical carcinoma. Since 2006, three prophylactic vaccines against HPV have been available on the market, including bivalent vaccines, quadrivalent vaccines, and nine-valent vaccines. Among them, nine-valent vaccines have been reported to be the most effective. They can prevent 97% of the high-grade pre-cancer lesions. Virus-like particles (VLPs), which are arranged as 360 copies of capsid proteins L1, are the only antigens of the HPV vaccine. Nine-valent HPV vaccines are prepared by mixing nine types of VLPs with adjuvants. Thus, the quality of the VLPs, including their stability and content in the HPV bulk, is very important for developing HPV vaccines. In this study, a method was developed for the determination of the nine types of VLPs (HPV6/11/16/18/31/33/45/52/58) in HPV bulk by size exclusion chromatography (SEC). The parameters of this method were optimized in terms of column brand, pore size of stationary phase particles, buffer concentration, and pH value. SHIMSEN Ankylo SEC-300 column (300 mm×7.8 mm, 3 µm) combined with a buffer aqueous solution containing 300 mmol/L NaCl and 50 mmol/L phosphate (pH 7.0) was utilized to separate the VLPs from the matrix since a narrow peak shape and good repeatability for VLPs could be obtained with this column and mobile phase. The optimized method had a wide linear range, good repeatability (RSDs of peak area were not more than 5.0%), and a satisfactory sensitivity (LOQs in the range of 4.58-15.24 µg/mL). The optimized method was used to determine the VLPs in the HPV bulk. The LOQs of the current method were much lower than the content of the nine types of VLPs in the HPV bulk, indicating that this method was sensitive enough for the determination of the nine types of VLPs in the HPV bulk. The method was also used to determine the VLPs in an HPV bulk that had been stored at 4 ℃ for one week. A decrease in the nine types of VLPs in the range of 10.0%-62.6% was observed after they were stored at 4 ℃ for one week. An HPV vaccine was prepared by mixing the VLPs with an adjuvant. Thereafter, the VLPs were adsorbed on the surface of the adjuvant. The developed method was applied to determine the free VLPs in twelve batches of HPV vaccines from three different manufacturers. No obvious free protein was detected in the twelve batches of the HPV vaccines from the three manufacturers, indicating that VLPs from these manufactures react well with their aluminum adjuvant. Folin-phenol (Lowry assay) is commonly used for the determination of proteins in vaccines. It is based on the reduction of phosphomolybdotungstic mixed acid chromogen in the phosphomolybdotungstic reagent, which results in an absorbance maximum at 650 nm. The Lowry method was sensitive to interfering substances. Most interfering substances caused a lower color yield, while some detergents caused a slight increase in color. To reduce the effect of the interfering substances, a procedure for precipitating the proteins was usually required before the sample was tested. Thus, the Lowry assay is complex, time-consuming, and of low selectivity. Compared to the Lowry method, the method we developed is simpler and more automatic. It is a high-throughput method of determining VLPs. It can be used to determine VLPs in HPV bulk and free VLPs in HPV vaccines.

Enantioselective Synthesis of Pyridines with All-Carbon Quaternary Carbon Centers via Cobalt-Catalyzed Desymmetric [2+2+2] Cycloaddition.

A Co-catalyzed enantioselective desymmetric [2+2+2] cycloaddition for synthesis of pyridines with all-carbon quaternary carbon centers has been developed. The regio- and enantioselectivities are controlled by the inherent nature of terminal alkynes and the substituents on the bisoxazolinephosphine ligands. Pyridines with 5-substitutents could be obtained with >20:1 regioselectivity and up to 94 % ee when terminal alkyl, alkenyl or silyl alkynes and DTBM/Ph-based NPN* ligand L6 were used. Terminal aryl alkynes and Ph/Bn-based ligand L4 leads to formation of pyridines with 6-substitutents in up to 99 % ee.