Concurrent binding to DNA and RNA facilitates the pluripotency reprogramming activity of Sox2.

Some transcription factors that specifically bind double-stranded DNA appear to also function as RNA-binding proteins. Here, we demonstrate that the transcription factor Sox2 is able to directly bind RNA in vitro as well as in mouse and human cells. Sox2 targets RNA via a 60-amino-acid RNA binding motif (RBM) positioned C-terminally of the DNA binding high mobility group (HMG) box. Sox2 can associate with RNA and DNA simultaneously to form ternary RNA/Sox2/DNA complexes. Deletion of the RBM does not affect selection of target genes but mitigates binding to pluripotency related transcripts, switches exon usage and impairs the reprogramming of somatic cells to a pluripotent state. Our findings designate Sox2 as a multi-functional factor that associates with RNA whilst binding to cognate DNA sequences, suggesting that it may co-transcriptionally regulate RNA metabolism during somatic cell reprogramming.

Silver-Templated γ-Keggin Alkyltin-Oxo Cluster: Electronic Structure and Optical Limiting Effect.

As one of the most representative polyoxometalate (POM) structures, Keggin clusters have attracted considerable attention. Nevertheless, the noble-metal-templated Keggin structure has not been reported to date. In this work, for the first time, a Ag atom was successfully incorporated to template the formation of a γ-Keggin alkytin-oxo cluster. Moreover, the central Ag atom has brought a significant heavy atom effect, showing the important influence on the electronic structure and optical properties. Theoretical calculations demonstrate that the Ag atom affects the frontier molecular orbitals and excited states of the AgSn12 cluster, and also the process of electron transfer. The solid structure of the AgSn12 cluster exhibits a significant third-order nonlinear optical (NLO) response, and an excellent optical limiting effect has been experimentally verified. The success of this work opens the way for the construction and optical properties modulation of noble metal templated Keggin structures.

A novel nickel-modified nano-magnetite for isolation of histidine-tagged proteins expressed in Escherichia coli.

Nano-magnetite with superparamagnetism could be coated by some organic compounds or by nano Au or Pt via surface modifications with multi-step reactions for the applications of isolating histidine-tagged (His-tagged) proteins. Introducing active sites of binding histidine onto the surface of nano-magnetite was the ultimate task. However, multi-step treatments might result in departure of the coatings from the surface of the nano-magnetite, which led to loss of active sites. In this work, we reported a convenient and efficient way of treating nano-magnetites and applied them in isolating His-tagged proteins. Carboxylates were introduced on the surface of home-made nano-magnetite directly via ultrasonic mixing with sodium bitartrate rather than complicated surface modifications, which was proved by thermogravimetric analyses. Ni2+ was, therefore, caught by the carboxylates of the coating via the coordinate interaction, demonstrated by X-ray photoelectron spectra. The coated magnetic nanoparticles with the bonded Ni2+ were successfully employed to selectively bind and separate recombinant His-tagged proteins directly from the mixture of Escherichia coli cell lysate, and showed wonderful affinity for His-tagged proteins with the saturated adsorption amount being 556 mg g-1. Additionally, such functionalized nano-magnetite manifested the excellent recyclability in isolating His-tagged proteins.

Recent Trends in Potential Therapeutic Applications of the Dietary Flavonoid Didymin.

Didymin (isosakuranetin 7-O-rutinoside) is an orally bioactive dietary flavonoid glycoside first found in citrus fruits. Traditionally, this flavonoid has long been used in Asian countries as a dietary antioxidant. Recent studies have provided newer insights into this pleiotropic compound, which could regulate multiple biological activities of many important signaling molecules in health and disease. Emerging data also presented the potential therapeutic application of dietary flavonoid glycoside didymin against cancer, neurological diseases, liver diseases, cardiovascular diseases, and other diseases. In this review, we briefly introduce the source and extraction methods of didymin, and summarize its potential therapeutic application in the treatment of various diseases, with an emphasis on molecular targets and mechanism that contributes to the observed therapeutic effects. The dietary flavonoid didymin can be used to affect health and disease with multiple therapeutic targets, and it is anticipated that this review will stimulate the future development of this potential dietary medicine.

Soulieoside O, a new cyclolanostane triterpenoid glycoside from Souliea vaginata.

A new cyclolanostane triterpenoid glycoside, soulieoside O (1), together with 25-O-acetylcimigenol-3-O-ß-d-xylopyranoside (2) and cimigenol-3-O-ß-d-xylopyranoside (3), was isolated from the rhizomes of Souliea vaginata. Their structures were characterized by spectroscopic analysis and chemical methods. The new compound showed moderate inhibitory activity against three human cancer cell lines with IC50 values of 9.3-22.5 µM.

Oleanane triterpene saponins with cardioprotective activity from Clinopodium polycephalum.

Two new triterpene saponins, clinopodiside VI (1) and saikosaponin c (2), along with six known saikosaponins (3-8), were isolated from the plant of Clinopodium polycephalum. Compounds 1-3 showed moderate inhibition against H9c2 cell damage induced by H2O2.

Arenobufagin Induces Apoptotic Cell Death in Human Non-Small-Cell Lung Cancer Cells via the Noxa-Related Pathway.

Arenobufagin, an active component isolated from the traditional Chinese medicine Chan Su, exhibits anticancer influences in several human malignancies. However, the effects and action mechanisms of arenobufagin on non-small-cell lung cancer (NSCLC) are still unknown. In this study, we reported that arenobufagin acted through activation of Noxa-related pathways and promoted apoptotic cell death in human NSCLC cells. Our results revealed that arenobufagin-induced apoptosis was caspase-dependent, as evidenced by the fact that caspase-9, caspase-3 and poly (ADP-ribose) polymerase (PARP) were cleaved, and pretreatment with a pan-caspase inhibitor Z-VAD-FMK inhibited the pro-apoptosis effect of arenobufagin. Mechanistically, we further found that arenobufagin rapidly upregulated the expression of the pro-apoptosis protein Noxa, and abrogated the anti-apoptosis protein Mcl-1, a major binding partner of Noxa in the cell. More importantly, the knockdown of Noxa greatly blocked arenobufagin-induced cell death, highlighting the contribution of this protein in the anti-NSCLC effects of arenobufagin. Interestingly, arenobufagin also increased the expression of p53, a direct transcriptional activator for the upregulation of the Noxa protein. Taken together, our results suggest that arenobufagin is a potential anti-NSCLC agent that triggers apoptotic cell death in NSCLC cells through interfering with the Noxa-related pathway.

[Studies on chemical constituents of Clinopodium chinense].

Twenty-eight compounds were isolated and purified from Clinopodium chinense by Sephedax LH-20, ODS, MCI and preparative HPLC. Their structures were identified as apigenin (1), apigenin-7-O-ß-D-glucopyranoside (2), apigenin-7-O-ß-D-glucuronopyranoside (3), thellungianol (4), apigenin-7-O-ß-D-rutinoside (5), luteolin (6), luteolin-4'-O-ß-D-glucopyranoside (7), apigenin-7-O-ß-D-pyranglycuronate butyl ester (8), luteolin-7-O-ß-D-rutinoside (9), luteolin-7-O-ß-D-noehesperidoside (10), acacetin (11), acacetin-7-O-ß-D-glucuronopyranoside (12), buddleoside (13), naringenin (14), pruning (15), nairutin (16), isosakuranetin (17), isosakuranin (18), didymin (19), hesperidin (20), kaempferol (21), quercetin (22), kaempferol-3-O-α-L-rahmnoside (23), p-hydroxycinnamic acid (24), caffeic acid (25), cis-3-[2-[1-(3,4-dihydroxy-phenyl)-1 -hydroxymethyl]-1,3-ben-zodioxol-5-yl]-(E)-2-propenoic acid (26), mesaconic acid (27), gentisic acid 5-O-ß-D-(6'-salicylyl)-glucopyranoside (28). Among them, compounds 7, 9-10, 12, 23, 26-28 were isolated from the Clinopodium for the first time. The protective effects of compounds 1-6, 8-17 and 19 against H2O2-induced H9c2 cardiomyocyte injury were tested, compounds 15 exhibited significantly protective effects. Compared with the cell viability of (62.12±6.18)% in the model, pruning exhibited viabilities of (84.25±7.36)% at 25.0 mg•L⁻¹, respectively, using quercetin as a positive control [cell viability of (84.55±8.26)%, 20 mg•L⁻¹].

A new phenylethanoid glycoside from Incarvillea compacta.

A new phenylethanoid glycoside, 3'''-O-methylcampneoside I (1), was isolated from the 90% ethanolic extract of the roots of Incarvillea compacta, together with three known compounds, campneoside I (2), ilicifolioside A (3), and campneoside II (4). Their structures were determined spectroscopically and compared with previously reported spectral data. Compound 1 existed as epimers and displayed better 1,1-diphenyl-2-picrylhydrazyl (DPPH)-free radical scavenging activity using di-tert-butyl-4-methylphenol (BHT) as the positive control. In addition, pretreatment of human HepG2 cells with compound 1 significantly increased the viability on CCl4-induced cell death.

Compositions, Formation Mechanism, and Neuroprotective Effect of Compound Precipitation from the Traditional Chinese Prescription Huang-Lian-Jie-Du-Tang.

Compounds in the form of precipitation (CFP) are universally formed during the decocting of Chinese prescriptions, such as Huang-Lian-Jie-Du-Tang (HLJDT). The formation rate of HLJDT CFP even reached 2.63% ± 0.20%. The identification by liquid chromatography mass spectrometry (LC-MS(n)) proved that the main chemical substances of HLJDT CFP are baicalin and berberine, which is coincident with the theory that the CFP might derive from interaction between acidic and basic compounds. To investigate the formation mechanism of HLJDT CFP, baicalin and berberine were selected to synthesize a simulated precipitation and then the baicalin-berberine complex was obtained. Results indicated that the melting point of the complex interposed between baicalin and berberine, and the UV absorption, was different from the mother material. In addition, ¹H-NMR integral and high-resolution mass spectroscopy (HR-MS) can validate that the binding ratio was 1:1. Compared with baicalin, the chemical shifts of H and C on glucuronide had undergone significant changes by ¹H-, (13)C-NMR, which proved that electron transfer occurred between the carboxylic proton and the lone pair of electrons on the N atom. Both HLJDT CFP and the baicalin-berberine complex showed protective effects against cobalt chloride-induced neurotoxicity in differentiated PC12 cells. It is a novel idea, studying the material foundation of CFP in Chinese prescriptions.

Antimalarial and Antiproliferative Cassane Diterpenes of Caesalpinia sappan.

Bioassay-guided fractionation of a methanol extract of the seeds of Caesalpinia sappan led to the isolation of 12 new cassane-type diterpenes, caesalsappanins A-L (1-12). Their structures were elucidated on the basis of NMR and HRESIMS analysis, and the absolute configuration of compound 1 was determined by single-crystal X-ray crystallography. All isolated compounds were tested against a chloroquine-resistant Plasmodium falciparum strain for antiplasmodial activities and against a small panel of human cancer cell lines for antiproliferative activities. Compounds 7 and 8 displayed antimalarial activity against the chloroquine-resistant K1 strain of P. falciparum with IC50 values of 0.78 and 0.52 µM and selectivity indices of 17.6 and 16.4, respectively. Compound 10 showed antiproliferative activity against the KB cancer cell line with an IC50 value of 7.4 µM.

[A new bisabolane-type sesquiterpenoid from Coreopsis tinctoria].

To study the chemical constituents of the inflorescences of Coreopsis tinctoria from Xinjiang, isolation and purification of constituents were carried out by column chromatography on macroporous resin (D101) , MCI gel, MDS gel, silica gel, Sephadex LH-20 and semi-preparative HPLC. The structures of the compounds were identified by physicchemical properties and spectral data analysis. Fourteen compounds were isolated and identified as coretinterpenoid A (1), coretinphenol (2), quercetin (3), quercetin-3-O-ß-glucopyranoside (4), luteolin (5), taxifolin (6), 7, 3', 5'-trihydroxyflavanone (7), isookanin (8), isookanin-7-O-ß-D-glucopyranoside (9), 5, 7, 3', 5'-tetrahydroxyflavanone-7-O-ß-D-glucopyranoside (10), butein (11), okanin (12), sulfuretin (13), and linocinnamarin (14). Compound 1 was a new isabolane-type sesquiterpenoid and compounds 4, 10 and 13 were isolated from this plant for the first time.

Two new acylated flavonol glycosides from the seeds of Lepidium sativum.

Two new acylated flavonol glycosides named kaempferol-3-O-(2-O-sinapoyl)-ß-D-galactopyranosyl-(1 → 2)-ß-D-glucopyranoside-7-O-α-L-rhamnopyranoside (1) and quercetin-3-O-(6-O-benzoyl)-ß-D-glucopyranosyl-(1 → 3)-ß-D-galactopyranoside-7-O-α-L-rhamnopyranoside (2), were isolated together with six known compounds from the seeds of L. sativum. Their structures were elucidated on the basis of spectroscopic analysis and chemical methods. In vitro 1 and 2 inhibited nitric oxide production in lipopolysaccharide (LPS)-stimulated RAW 264.7 cells, with IC50 values of 25.36 and 25.08 µM, respectively.

[Triterpene constituents from Rosa cymosa Tratt].

The constituents in 95% ethanol extract of the root of Rosa cymosa Tratt were purified by column chromatography techniques, leading to isolation of eleven triterpenes. Their structures were elucidated by spectroscopic data as pomolic acid (1), fupenzic acid (2), ursolic acid (3), euscaphic acid (4), arjunic acid (5), tomentic acid (6), 3ß-E-feruloyl corosolic acid (7), 1ß-hydroxyeuscaphic acid (8), myrianthic acid (9), cecropiacic acid (10), and ilexoside B (11). Among them, compounds 3, 6-8, 10 and 11 were obtained from this plant for the first time, and compounds 7 and 10 were obtained from this genus for the first time.

Preparative isolation and purification of five flavonoid glycosides and one benzophenone galloyl glycoside from Psidium guajava by high-speed counter-current chromatography (HSCCC).

Psidium guajava leaves have a diverse phytochemical composition including flavonoids, phenolics, meroterpenoids and triterpenes, responsible for the biological activities of the medicinal parts. In particular, flavonol glycosides show beneficial effects on type II diabetes mellitus. A simple and efficient HSCCC method has been developed for the preparative separation of five flavonoid glycosides and one diphenylmethane glycoside from P. guajava. A solvent system composed of n-hexane-ethyl acetate-methanol-water (0.7:4:0.8:4, v/v/v/v) was optimized for the separation. The upper phase was used as the stationary phase, and the lower phase was used as the mobile phase. Under the optimized conditions, hyperoside (15.3 mg), isoquercitrin (21.1 mg), reynoutrin (65.2 mg), quercetin-3-O-ß-D-arabinopyranoside (71.7 mg), quercetin-3-O-α-L-arabinofuranoside (105.6 mg) and 2,4,6-trihydroxy-3,5-dimethylbenzophenone 4-O-(6''-O-galloyl)-ß-D-glucopyranoside (98.4 mg) were separated from crude sample (19.8 g). The structures of all the isolates were identified by ESI-MS, 1H- and 13C-NMR analyses and their purities (>95%) were determined using HPLC.

Two new cycloartane triterpenoid glycosides from the rhizomes of Actaea vaginata.

Two new cycloartane triterpenoid glycosides, soulieoside V (1) and 15-deacetylbeesioside O (2), together with one known compound, beesioside J (3), were isolated from the ethanolic extract of the rhizomes of Actaea vaginata. Their structures were elucidated by spectroscopic methods and by comparison with data reported in the literature. All the compounds were tested for their cytotoxic activities against human cancer cell lines.

Retrospective validation of ultrasound characteristics at 19-24 weeks as predictive tools for selective intrauterine growth restriction in monochorionic diamniotic twin pregnancies: a diagnostic study.

Background: Seeking an optimal time point for ultrasound examination is important for the diagnosis of late selective intrauterine growth restriction (sIUGR) at birth in monochorionic diamniotic (MCDA) twin pregnancies. We aimed to assess the role of ultrasound characteristics at 19-24 weeks as predictive tools for late sIUGR at birth in MCDA twin pregnancies. Methods: We retrospectively recruited 32 sIUGR and 56 normal patients with MCDA twin pregnancies. Ultrasound indexes of these included subjects at 19-24 weeks, including the middle cerebral artery peak systolic velocity (MCA-PSV), umbilical artery pulsatility index (UA-PI), middle cerebral artery pulsatility index (MCA-PI), and cerebroplacental ratio (CPR) were assessed. Receiver operating characteristic (ROC) curves were used to ascertain the predictive value of ultrasound characteristics discrepancy for such complications, and the relationship between the ultrasound characteristics and sIUGR was assessed by a logistic regression analysis. Results: Differences were found in the MCA-PI, UA-PI, and CPR discordances between the normal MCDA and sIUGR subjects. CPR discordance was the most effective characteristic for predicting sIUGR [area under the ROC curve (AUC) =0.883; 95% CI: 0.795-0.948], followed by UA-PI discordance (AUC =0.772; 95% CI: 0.685-0.829), and MCA-PI discordance (AUC =0.746; 95% CI: 0.681-0.823), respectively. Additionally, the optimal cutoff value of CPR discordance was 21.65, and the corresponding sensitivity and specificity were 0.750 and 0.929, respectively. The correlation analysis revealed that gestational age (GA) at ultrasound scan but not at delivery was significantly correlated with the MCA-PSV (r=0.55, P<0.01), UA-PI (r=0.55, P<0.01), MCA-PI (r=0.49, P<0.01), and CPR (r=0.55, P<0.01) in sIUGR, while GA at both ultrasound scan and birth was significantly correlated with MCA-PSV (r=0.65, P<0.01), UA-PI (r=0.49, P<0.01), MCA-PI (r=0.48, P<0.01), and CPR (r=0.63, P<0.01) in normal MCDA. Conclusions: Increased MCA-PI, UA-PI, and CPR discordances were found in fetuses with sIUGR. CPR discordance could serve as a predictive index for sIUGR. An early ultrasound examination may be more accurate than biochemical modality for sIUGR prediction.

Soulieoside U, a new cycloartane triterpene glycoside from Actaea vaginata.

One new cycloartane triterpene bisdesmoside, soulieoside U, was isolated from the rhizomes of Actaea vaginata. Its structure was elucidated by extensive analysis of the NMR and MS data. Soulieoside U was evaluated for cytotoxic activities against three human cancer cell lines.

Highly Prevalent SARS-CoV-2 Antigenemia in COVID-19 Patients.

Background: Many issues, such as severity assessment and antibody responses, remain to be answered eagerly for evaluation and understanding of COVID-19. Immune lesion is one of key pathogenesis of the disease. It would be helpful to understand the disease if an investigation on antigenemia and association was conducted in the patients with SARS-CoV-2 infection. Methods: A total of 156 patients admitted to the First People's Hospital of Hefei or Anhui Provincial Hospital on January to February 2020 were involved in this study. SARS-CoV-2 nucleocapsid (NP) antigen, specific IgM/IgG antibodies, and RNA were detected in sequential sera from three COVID-19 patients, and additional 153 COVID-19 patients by means of NP-antigen capture enzyme-linked immunosorbent assay, colloidal gold quick diagnosis, and real-time RT-PCR, respectively. The clinical types of COVID-19 patients were classified into asymptomatic, mild, moderate, severe, and critical, following on the Chinese guideline of COVID-19 diagnosis and treatment. The demographic and clinical data of patients were obtained for comparable analysis. Results: NP antigen was detected in 5 of 20 sequential sera collected from three COVID-19 patients with typically clinical symptoms, and 60.13% (92/153) expanded samples collected within 17 days after illness onset. No SARS-CoV-2 RNA segment was detected in these sera. The NP positive proportion reached a peak (84.85%, 28/33) on 6 to 8 days after illness onset. Both NP concentration and positive proportion were increased with the increase of clinical severity of COVID-19. Compared to NP negative patients, NP positive patients had older age [years, medians (interquartile ranges (IQR)), 49 (6) vs. 31 (11)], lower positive proportion of NP specific IgM [27.17% (25/92) vs. 59.02% (36/61)], and IgG [21.74% (20/92) vs. 59.02% (36/61)] antibodies, and longer duration [days, medians (IQR), 24 (10) vs. 21 (13)] from illness to recovery. Conclusions: SARS-CoV-2 NP antigenemia occurred in COVID-19, and presented highly prevalent at early stage of the disease. The antigenemia was related to clinical severity of the disease, and may be responsible for the delay of detectable SARS-Cov-2 IgM.