Fabrication and application of a novel electrochemical biosensor based on a mesoporous carbon sphere@UiO-66-NH2/Lac complex enzyme for tetracycline detection.

The overuse of tetracycline results in a threat to human, poultry and livestock health. An enzymatic electrochemical biosensor is an ideal alternative method for accurate and rapid tetracycline detection, while the unstable and easily deactivated nature of the enzyme limits its development. To overcome these limitations, a highly sensitive enzymatic electrochemical biosensor for the determination of tetracycline is developed in this work based on a complex enzyme which was constructed using a mesoporous carbon sphere@UiO-66-NH2 (MCS@UiO-66-NH2) core-shell composite with embedded laccase (Lac). Compared to pure MCS and UiO-66-NH2, the MCS@UiO-66-NH2 core-shell composite has an advantageous mesoporous structure (pore diameter >8 nm), which is suitable for the immobilization of small laccase. The biosensor based on the complex enzyme exhibits a superior activity and enhanced stability as compared with that made using a pure enzyme because the mesoporous structure of the MCS@UiO-66-NH2 composite can effectively protect the laccase against inactivation and denaturation. Besides, its high specific surface area and good conductivity are beneficial to enzyme immobilization and electron transfer in the modified electrode. The biosensor based on this complex enzyme exhibits a relatively low detection limit of 8.94 × 10-7 mol L-1 and a detection range of 1.0 × 10-6-6.0 × 10-5 mol L-1 for tetracycline detection. Furthermore, the developed biosensor possesses good long-term stability, selectivity and reproducibility, indicating its potential application for tetracycline determination in actual food. This research work provides a prospective solution to resolve the stability and inactivation problems of enzymatic electrochemical biosensors in different application scenarios.

Radical Stabilization of a Tripyridinium-Triazine Molecule Enables Reversible Storage of Multiple Electrons.

A novel organic molecule, 2,4,6-tris[1-(trimethylamonium)propyl-4-pyridiniumyl]-1,3,5-triazine hexachloride, was developed as a reversible six-electron storage electrolyte for use in an aqueous redox flow battery (ARFB). Physicochemical characterization reveals that the molecule evolves from a radical to a biradical and finally to a quinoid structure upon accepting four electrons. Both the diffusion coefficient and the rate constant were sufficiently high to run a flow battery with low concentration and kinetics polarization losses. In a demonstration unit, the assembled flow battery affords a high specific capacity of 33.0 Ah L-1 and a peak power density of 273 mW cm-2 . This work highlights the rational design of electroactive organics that can manipulate multi-electron transfer in a reversible way, which will pave the way to development of energy-dense, manageable and low-cost ARFBs.

Efficient Nitrogen-Doped Carbon for Zinc-Bromine Flow Battery.

The zinc-bromine flow battery (ZBFB) is one of the most promising technologies for large-scale energy storage. Here, nitrogen-doped carbon is synthesized and investigated as the positive electrode material in ZBFBs. The synthesis includes the carbonization of the glucose precursor and nitrogen doping by etching in ammonia gas. Physicochemical characterizations reveal that the resultant carbon exhibits high electronic conductivity, large specific surface area, and abundant heteroatom-containing functional groups, which benefit the formation and exposure of the active sites toward the Br2 /Br- redox couple. As a result, the assembled ZBFB achieves a voltage efficiency of 83.0% and an energy efficiency of 82.5% at a current density of 80 mA cm-2 , which are among the top values in literature. Finally, the ZBFB does not yield any detectable degradation in performance after a 200-cycle charging/discharging test, revealing its high stability. In summary, this work provides a highly efficient electrode material for the zinc-bromine flow battery.

Sialic Acid Linkage Specific Derivatization of Glycosphingolipid Glycans by Ring-Opening Aminolysis of Lactones.

Sialic acids occur widely as glycoconjugates at the nonreducing ends of glycans. Glycosphingolipids (GSLs) include a large number of sialyl-linked glycan isomers with α2,3-, α2,6-, and α2,8-linked polysialic acids. Thus, it is difficult to distinguish structural isomers with the same mass by mass spectrometry. The sialic acid linkage specific alkylamidation (SALSA) method has been developed for discriminating between α2,3- and α2,6-linked isomers, but sequential amidation of linkage-specific sialic acids is generally complicated and time-consuming. Moreover, analysis of GSL-glycans containing α2,8-linked polysialic acids using solid-phase SALSA has not been reported. Herein, we report a novel SALSA method focused on ring-opening aminolysis (aminolysis-SALSA), which shortens the reaction time and simplifies the experimental procedures. We demonstrate that aminolysis-SALSA can successfully distinguish serum GSL-glycan isomers by mass spectrometry. In addition, ring-opening aminolysis can easily be applied to amine and hydrazine derivatives.

Genetic heterogeneity of uncharacterized childhood autoimmune diseases with lymphoproliferation.

Autoimmune diseases in children are rare and can be difficult to diagnose.  Single causative genes have been identified for some pediatric autoimmune diseases. Such orphan diseases may not be diagnosed properly due to the variability of patients' phenotypes. Guidelines for the diagnostic process need to be developed. Fifteen patients with uncharacterized childhood autoimmune diseases with lymphoproliferation that had negative testing for autoimmune lymphoproliferative syndrome were subjected to whole-exome sequencing to identify genes associated with these conditions. Five causative genes, CTLA4, STAT3, TNFAIP3, IKZF1, and PSTPIP1, were identified. These genes should be considered as candidates for uncharacterized childhood autoimmune diseases with lymphoproliferation.

Haploinsufficiency of TNFAIP3 (A20) by germline mutation is involved in autoimmune lymphoproliferative syndrome.

BACKGROUND: Autoimmune diseases in children are rare and can be difficult to diagnose. Autoimmune lymphoproliferative syndrome (ALPS) is a well-characterized pediatric autoimmune disease caused by mutations in genes associated with the FAS-dependent apoptosis pathway. In addition, various genetic alterations are associated with the ALPS-like phenotype. OBJECTIVE: The aim of the present study was to elucidate the genetic cause of the ALPS-like phenotype. METHODS: Candidate genes associated with the ALPS-like phenotype were screened by using whole-exome sequencing. The functional effect of the identified mutations was examined by analyzing the activity of related signaling pathways. RESULTS: A de novo heterozygous frameshift mutation of TNF-α-induced protein 3 (TNFAIP3, A20), a negative regulator of the nuclear factor κB pathway, was identified in one of the patients exhibiting the ALPS-like phenotype. Increased activity of the nuclear factor κB pathway was associated with haploinsufficiency of TNFAIP3 (A20). CONCLUSION: Haploinsufficiency of TNFAIP3 (A20) by a germline heterozygous mutation leads to the ALPS phenotype.

Impact of the Niemann-Pick c1 Gene Mutation on the Total Cellular Glycomics of CHO Cells.

Niemann-Pick disease type C (NPC) is an autosomal recessive lipid storage disorder, and the majority of cases are caused by mutations in the NPC1 gene. In this study, we clarified how a single gene mutation in the NPC1 gene impacts the cellular glycome by analyzing the total glycomic expression profile of Chinese hamster ovary cell mutants defective in the Npc1 gene (Npc1 KO CHO cells). A number of glycomic alterations were identified, including increased expression of lactosylceramide, GM1, GM2, GD1, various neolacto-series glycosphingolipids, and sialyl-T (O-glycan), which was found to be the major sialylated protein-bound glycan, as well as various N-glycans, which were commonly both fucosylated and sialylated. We also observed significant increases in the total amounts of free oligosaccharides (fOSs), especially in the unique complex- and hybrid-type fOSs. Treatment of Npc1 KO CHO cells with 2-hydroxypropyl-ß-cyclodextrin (HPBCD), which can reduce cholesterol and glycosphingolipid (GSL) storage, did not affect the glycomic alterations observed in the GSL-, N-, and O-glycans of Npc1 KO CHO cells. However, HPBCD treatment corrected the glycomic alterations observed in fOSs to levels observed in wild-type cells.

Total cellular glycomics allows characterizing cells and streamlining the discovery process for cellular biomarkers.

Although many of the frequently used pluripotency biomarkers are glycoconjugates, a glycoconjugate-based exploration of novel cellular biomarkers has proven difficult due to technical difficulties. This study reports a unique approach for the systematic overview of all major classes of oligosaccharides in the cellular glycome. The proposed method enabled mass spectrometry-based structurally intensive analyses, both qualitatively and quantitatively, of cellular N- and O-linked glycans derived from glycoproteins, glycosaminoglycans, and glycosphingolipids, as well as free oligosaccharides of human embryonic stem cells (hESCs), induced pluripotent stem cells (hiPSCs), and various human cells derived from normal and carcinoma cells. Cellular total glycomes were found to be highly cell specific, demonstrating their utility as unique cellular descriptors. Structures of glycans of all classes specifically observed in hESCs and hiPSCs tended to be immature in general, suggesting the presence of stem cell-specific glycosylation spectra. The current analysis revealed the high similarity of the total cellular glycome between hESCs and hiPSCs, although it was suggested that hESCs are more homogeneous than hiPSCs from a glycomic standpoint. Notably, this study enabled a priori identification of known pluripotency biomarkers such as SSEA-3, -4, and -5 and Tra-1-60/81, as well as a panel of glycans specifically expressed by hESCs and hiPSCs.

Quantitative O-Glycomics by Microwave-Assisted ß-Elimination in the Presence of Pyrazolone Analogues.

O-Linked glycosylation of serine/threonine residues is a posttranslational modification of proteins and is essential for protein recognition and lipid functions on cell surfaces and within cells. The characterization of differently structured O-linked glycans (O-glycans) is particularly challenging because there is no known endoglycosidase for such groups. Therefore, chemical digestion approaches have been widely used; however, it is sometimes difficult to suppress unwanted side reactions. Recently, we reported a novel O-glycomics procedure using ß-elimination in the presence of pyrazolone analogues (BEP). In the present study, we describe a microwave (MW)-assisted BEP procedure for rapid and quantitative O-glycomic analysis. Following optimization of the reaction conditions, the MW-assisted BEP reaction substantially improved the recovery of total O-glycans from model glycoproteins (PSM) and the reaction time was reduced from 16 to 2 h. Combined with sequential solid-phase extractions, this MW-assisted BEP procedure enabled O-glycomic analyses of various biological samples.

Angiotensin-converting enzyme gene insertion-deletion polymorphism is a risk marker for Alzheimer's disease in a Chinese population: a meta-analysis of case-control studies.

It has long been known that the polymorphisms of angiotensin-converting enzyme gene (ACE) are associated to increase risk of Alzheimer's disease (AD) in Chinese population. However, consistent results were not obtained among studies. This study is aimed to clarify the association between ACE insertion (I)/deletion (D) polymorphism (rs1799752) and AD. Literatures were searched from PubMed, Embase, Cochrane Library, CNKI, Wanfang and VIP databases without language restrictions. Eleven separate studies were suitable for the inclusion criterion. The selected studies contained 2,763 Chinese participants, including 1,383 in AD group and 1,380 controls. Pooled odds ratios (ORs) were calculated to assess the association between ACE I/D polymorphism and AD. Our case-control data indicated that ACE insertion is a risk allele in all genetic models: additive model (I vs. D: OR = 1.32, 95 % CI 1.07-1.62, P = 0.008), dominant model (II + ID vs. DD: OR = 1.61, 95 % CI 1.08-2.41, P = 0.02) and recessive model (II vs. ID + DD: OR = 1.39, 95 % CI 1.07-1.81, P = 0.01). Heterogeneity between studies was significant (P < 0.10) but not in stratification defined by the selection of controls (P > 0.10). After stratification according to the selection of controls, the carrier of ACE I allele remained a high risk for AD in population-based samples subgroup (I vs. D: P = 0.008, OR = 1.32, 95 % CI 1.07-1.61, P(heterogeneity) = 0.47, I (2) = 0 %). Our study provided solid evidence suggesting that ACE gene I/D polymorphism is a genetic risk factor for AD in Chinese population.

Association between Common Genetic Variants of α2A-, α2B-, and α2C-Adrenergic Receptors and Orthostatic Hypotension.

BACKGROUND: The genetic background associated with the dysregulation of orthostatic blood pressure remains poorly understood. The sympathetic nervous system plays a pivotal role in the regulation of blood pressure, as well as in response to positional changes. The essential role of adrenergic receptors in the sympathetic nervous system prompted us to hypothesize that common genetic variants of the α2-adrenergic receptor might contribute to the dysregulation of orthostatic blood pressure in general populations. This study is to explore the association between the polymorphisms of the α2-adrenergic receptor genes and the occurrence of orthostatic hypotension in Chinese populations. METHODS: The polymorphisms ADRA2A C-1291G (rs1800544), ADRA2B 301-303 I/D (rs28365031), and ADRA2C 322-325 I/D (rs61767072) were genotyped in 317 patients with orthostatic hypotension and 664 age- and gender-matched controls. Logistic regression analyses, adjusted for multiple comparisons, were used to determine the association between the allele/genotype of each ADRA2 gene and the risk of orthostatic hypotension. RESULTS: No significant association was found between the ADRA2A C-1291G, ADRA2B 301-303 I/D, and ADRA2C 322-325 I/D polymorphisms and orthostatic hypotension. CONCLUSIONS: We concluded that the common polymorphisms in the alpha2-adrenergic receptor gene is not associated with orthostatic hypotension risk in Chinese.

Process for immune defect and chromosomal translocation during early thymocyte development lacking ATM.

Immune defect in ataxia telangiectasia patients has been attributed to either the failure of V(D)J recombination or class-switch recombination, and the chromosomal translocation in their lymphoma often involves the TCR gene. The ATM-deficient mouse exhibits fewer CD4 and CD8 single-positive T cells because of a failure to develop from the CD4(+)CD8(+) double-positive phase to the single-positive phase. Although the occurrence of chromosome 14 translocations involving TCR-δ gene in ATM-deficient lymphomas suggests that these are early events in T-cell development, a thorough analysis focusing on early T-cell development has never been performed. Here we demonstrate that ATM-deficient mouse thymocytes are perturbed in passing through the ß- or γδ-selection checkpoint, leading in part to the developmental failure of T cells. Detailed karyotype analysis using the in vitro thymocyte development system revealed that RAG-mediated TCR-α/δ locus breaks occur and are left unrepaired during the troublesome ß- or γδ-selection checkpoints. By getting through these selection checkpoints, some of the clones with random or nonrandom chromosomal translocations involving TCR-α/δ locus are selected and accumulate. Thus, our study visualized the first step of multistep evolutions toward lymphomagenesis in ATM-deficient thymocytes associated with T-lymphopenia and immunodeficiency.

Artemis-dependent DNA double-strand break formation at stalled replication forks.

Stalled replication forks undergo DNA double-strand breaks (DSBs) under certain conditions. However, the precise mechanism underlying DSB induction and the cellular response to persistent replication fork stalling are not fully understood. Here we show that, in response to hydroxyurea exposure, DSBs are generated in an Artemis nuclease-dependent manner following prolonged stalling with subsequent activation of the ataxia-telangiectasia mutated (ATM) signaling pathway. The kinase activity of the catalytic subunit of the DNA-dependent protein kinase, a prerequisite for stimulation of the endonuclease activity of Artemis, is also required for DSB generation and subsequent ATM activation. Our findings indicate a novel function of Artemis as a molecular switch that converts stalled replication forks harboring single-stranded gap DNA lesions into DSBs, thereby activating the ATM signaling pathway following prolonged replication fork stalling.

Functional studies of a novel germline p53 splicing mutation identified in a patient with Li-Fraumeni-like syndrome.

Most p53 mutations identified in Li-Fraumeni syndrome (LFS) are missense mutations; splicing mutations have rarely been reported. A novel splicing p53 mutation was identified in a patient with Li-Fraumeni-like syndrome (LFL). Usually, p53 missense mutants identified in LFS and cancer cells function as dominant negative mutations interfering with wild-type p53 function. However, the mechanism by which p53 haploinsufficiency causes carcinogenesis is not well characterized. In this study, we describe a novel splicing mutation that results in the loss-of-function of p53. These findings suggest a linkage between the loss-of-function type p53 mutation and a LFL phenotype.

Autoimmune lymphoproliferative syndrome-like disease with somatic KRAS mutation.

Autoimmune lymphoproliferative syndrome (ALPS) is classically defined as a disease with defective FAS-mediated apoptosis (type I-III). Germline NRAS mutation was recently identified in type IV ALPS. We report 2 cases with ALPS-like disease with somatic KRAS mutation. Both cases were characterized by prominent autoimmune cytopenia and lymphoadenopathy/splenomegaly. These patients did not satisfy the diagnostic criteria for ALPS or juvenile myelomonocytic leukemia and are probably defined as a new disease entity of RAS-associated ALPS-like disease (RALD).

[Effect of Dingguier umbilical paste on rats with functional dyspepsia and mice with splenic asthenia].

OBJECTIVE: To observe the effect of Dingguier umbilical paste on rats with functional dyspepsia and mice with splenic asthenia, and investigate the related mechanism. METHOD: Functional dyspepsia models of rats were made by irregular food intake plus diluted hydrochloric acid. Successional treatments were offered for 14 days. The rats weights, contents of serum NO, AChE and MC were measured. The rats with splenic asthenia were made by rhubarb feed, and observed the affection of gastric emptying. RESULT: Compared with those in the model control group, the weight of rats in all dosages Dingguier umbilical paste groups increased obviously (P < 0.05), pepsin activity of rats in the dosage (1.34 g x kg(-1)) Dingguier umbilical paste groups was significantly higher and the contents of NO and quantities of MC in the dosage (2.67 g x kg(-1)) Dingguier umbilical paste groups decreased clearly (P < 0.05), and the contents of serum AChE in all dosages Dingguier umbilical paste groups rose apparently. The weight of mice with splenic asthenia increased obviously, accelerated gastric emptying, and improved the symptom. CONCLUSION: Dingguier umbilical paste has significant improvement of indigestion. The related mechanism may be to reduce the content of serum NO and the quantity of MC and enhance the content of serum AChE.

Targeting Poly(ADP)ribose polymerase in BCR/ABL1-positive cells.

BCR/ABL1 causes dysregulated cell proliferation and is responsible for chronic myelogenous leukemia (CML) and Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph1-ALL). In addition to the deregulatory effects of its kinase activity on cell proliferation, BCR/ABL1 induces genomic instability by downregulating BRCA1. PARP inhibitors (PARPi) effectively induce cell death in BRCA-defective cells. Therefore, PARPi are expected to inhibit growth of CML and Ph1-ALL cells showing downregulated expression of BRCA1. Here, we show that PARPi effectively induced cell death in BCR/ABL1 positive cells and suppressed colony forming activity. Prevention of BCR/ABL1-mediated leukemogenesis by PARP inhibition was tested in two in vivo models: wild-type mice that had undergone hematopoietic cell transplantation with BCR/ABL1-transduced cells, and a genetic model constructed by crossing Parp1 knockout mice with BCR/ABL1 transgenic mice. The results showed that a PARPi, olaparib, attenuates BCR/ABL1-mediated leukemogenesis. One possible mechanism underlying PARPi-dependent inhibition of leukemogenesis is increased interferon signaling via activation of the cGAS/STING pathway. This is compatible with the use of interferon as a first-line therapy for CML. Because tyrosine kinase inhibitor (TKI) monotherapy does not completely eradicate leukemic cells in all patients, combined use of PARPi and a TKI is an attractive option that may eradicate CML stem cells.

Myeloid/natural killer (NK) cell precursor acute leukemia as a distinct leukemia type.

Myeloid/natural killer (NK) cell precursor acute leukemia (MNKPL) has been described on the basis of its unique immunophenotype and clinical phenotype. However, there is no consensus on the characteristics for identifying this disease type because of its rarity and lack of defined distinctive molecular characteristics. In this study, multiomics analysis revealed that MNKPL is distinct from acute myeloid leukemia, T cell acute lymphoblastic leukemia, and mixed-phenotype acute leukemia (MPAL), and NOTCH1 and RUNX3 activation and BCL11B down-regulation are hallmarks of MNKPL. Although NK cells have been classically considered to be lymphoid lineage-derived, the results of our single-cell analysis using MNKPL cells suggest that NK cells and myeloid cells share common progenitor cells. Treatment outcomes for MNKPL are unsatisfactory, even when hematopoietic cell transplantation is performed. Multiomics analysis and in vitro drug sensitivity assays revealed increased sensitivity to l-asparaginase and reduced levels of asparagine synthetase (ASNS), supporting the clinically observed effectiveness of l-asparaginase.

Chemical compositions extracted from Wikstroemia indica and their multiple activities.

CONTEXT: The rhizome of Wikstroemia indica (L.) C. A. Mey (Thymelaeaceae) is widespread in China which has been widely used in China as folk medicine for the treatment of syphilis, arthritis, whooping cough, and cancer. Due to its multiactivities, its extract has an attractive potential as a promising natural agent in the pharmaceutical industries. OBJECTIVE: Aims of this study were to optimize the extraction process of the flavonoids from W. indica, and evaluate its multiple activities. MATERIALS AND METHODS: An orthogonal test design was employed to optimize the extraction procedure of flavonoids from W. indica. And multichromatography and spectroscopy were used to study the chemical compounds of W. indica, while several bioactivity assays were used to evaluate the antibacterial, anti-inflammatory, and antitumor activities of W. indica. RESULTS: Optimal extraction conditions were determined: ethanol concentration was 60%; extraction time was 60 min; liquid-solid ratio was 16:1 and the power of ultrasonic instrument was 160 W. Four compounds: daphnoretin, chrysophanol, myricitrime and rutin were purified from W. indica, and chrysophanol was identified from this plant for the first time. The extract of W. indica displayed significant antimicrobial and anti-inflammatory activities. Daphnoretin showed a significant inhibition effect on CNE cells and HeLa cells lines at the concentrations ranging from 15.6 to 125 µg/mL, the tendency of antitumor effect was displayed in a concentration-dependent manner. DISCUSSION AND CONCLUSIONS: Extracts of W. indica could potentially be used as a promising natural agent in the pharmaceutical industries.

Modulating p-Orbital of Bismuth Nanosheet by Nickel Doping for Electrocatalytic Carbon Dioxide Reduction Reaction.

Electrochemical reduction of CO2 (CO2 RR) to value-added chemicals is an effective way to harvest renewable energy and utilize carbon dioxide. However, the electrocatalysts for CO2 RR suffer from insufficient activity and selectivity due to the limitation of CO2 activation. In this work, a Ni-doped Bi nanosheet (Ni@Bi-NS) electrocatalyst is synthesized for the electrochemical reduction of CO2 to HCOOH. Physicochemical characterization methods are extensively used to investigate the composition and structure of the materials. Electrochemical results reveal that for the production of HCOOH, the obtained Ni@Bi-NS exhibits an equivalent current density of 51.12 mA cm-2 at -1.10 V, which is much higher than the pure Bi-NS (18.00 mA cm-2 at -1.10 V). A high Faradaic efficiency over 92.0 % for HCOOH is achieved in a wide potential range from -0.80 to -1.10 V, and particularly, the highest efficiency of 98.4 % is achieved at -0.90 V. Both experimental and theoretical results reveal that the superior activity and selectivity are attributed to the doping effect of Ni on the Bi nanosheet. The density functional theory calculation reveals that upon doping, the charge is transferred from Ni to the adjacent Bi atoms, which shifts the p-orbital electronic density states towards the Fermi level. The resultant strong orbital hybridization between Bi and the π* orbitals of CO2 facilitates the formation of *OCHO intermediates and favors its activation. This work provides an effective strategy to develop active and selective electrocatalysts for CO2 RR by modulating the electronic density state.