Porous superabsorbent composites prepared from aqueous foam template and application evaluation

Rapid water absorption is very important for the application of superabsorbent polymers under dry or semi-dry conditions, but there are currently few relevant studies. In this context, a novel porous superabsorbent of chitosan-grafted acrylic copolymer-2-acrylamido-2-methylpropanesulfonic acid/sapindus mukorossi pericarp/calcined oil shale semi-coke (CS-g-P(AA-co-AMPS)/SMP/COSSC) was prepared by a green and convenient foam template method, which was triggered by redox polymerization. The rich pore structure of the porous superabsorbent was conducive to accelerating the water absorption rate. It only took 15 min to reach a swelling capacity of 650 g g-1 in distilled water. Soil experiments show that even with the addition of 0.5 wt% porous superabsorbent, the soil water retention time can be extended to 7 days. Finally, it was applied to the growth of cabbage seeds and it was found that the growth was significantly improved. Based on these excellent properties, we expect to provide a valuable reference for the preparation of fast-absorbing materials through the green water-based foam template method, contributing to sustainable agriculture.

Selective and Sustainable Production of Sub-terminal Hydroxy Fatty Acids by a Self-Sufficient CYP102 Enzyme from Bacillus Amyloliquefaciens

Enzymatic hydroxylation of fatty acids by Cytochrome P450s (CYPs) offers an eco-friendly route to hydroxy fatty acids (HFAs), high-value oleochemicals with various applications in materials industry and with potential as bioactive compounds. However, instability and poor regioselectivity of CYPs are their main drawbacks. A newly discovered self-sufficient CYP102 enzyme, BAMF0695 from Bacillus amyloliquefaciens DSM 7, exhibits preference for hydroxylation of sub-terminal positions (ω-1, ω-2, and ω-3) of fatty acids. Our studies show that BAMF0695 has a broad temperature optimum (over 70 % of maximal enzymatic activity retained between 20 to 50 °C) and is highly thermostable (T50 >50 °C), affording excellent adaptive compatibility for bioprocesses. We further demonstrate that BAMF0695 can utilize renewable microalgae lipid as a substrate feedstock for HFA production. Moreover, through extensive site-directed and site-saturation mutagenesis, we isolated variants with high regioselectivity, a rare property for CYPs that usually generate complex regioisomer mixtures. BAMF0695 mutants were able to generate a single HFA regiosiomer (ω-1 or ω-2) with selectivities from 75 % up to 91 %, using C12 to C18 fatty acids. Overall, our results demonstrate the potential of a recent CYP and its variants for sustainable and green production of high-value HFAs.

[Research progress in anti-reflux reconstructions and mechanism after proximal gastrectomy]

The electrophysiological activity of the gastrointestinal tract and the mechanical anti-reflux structure of the gastroesophageal junction are the basis of the anti-reflux function of the stomach. Proximal gastrectomy destroys the mechanical structure and normal electrophysiological channels of the anti-reflux. Therefore, the residual gastric function is disordered. Moreover, gastroesophageal reflux is one of the most serious complications. The emergence of various types of anti-reflux surgery through the mechanism of reconstructing mechanical anti-reflux barrier and establishing buffer zone, and the preservation of, the pacing area and vagus nerve of the stomach, the continuity of the jejunal bowel, the original gastroenteric electrophysiological activity of the gastrointestinal tract, and the physiological function of the pyloric sphincter, are all important measures for gastric conservative operations. There are many types of reconstructive approaches after proximal gastrectomy. The design based on the anti-reflux mechanism and the functional reconstruction of mechanical barrier, and the protection of gastrointestinal electrophysiological activities are important considerations for the selected of reconstructive approaches after proximal gastrectomy. In clinical practice, we should consider the principle of individualization and the safety of radical resection of tumor to select a rational reconstructive approaches after proximal gastrectomy.

Implementing Climate Change Adaptation in Territory Spatial Planning Systems: Challenges and Approaches Based on Practices in Guiyang

Integrating climate change adaptation into spatial planning has become a global goal in the field of spatial planning. Despite the various relevant policies proposed by governments, there is still a lack of common practice in the field of climate change research and territory spatial planning preparation and research in China. In this study, climate change adaptation planning in the territory spatial planning system (TSPS), based upon risk assessment, is explored using downscaled climate change prediction data (derived from CMIP5) and prefectural master territory spatial planning (MTSP) data from Guiyang. The study found that such practices, despite their feasibility, still face systemic challenges given the current planning system in China, e.g., the deficiency of climate change impact data and analyses, the absence of essential planning tools, and the unsuitability of the current planning system for the integration of adaptation actions. We propose corresponding approaches based on our empirical planning experience and discuss prospects for relevant research and planning.

Usefulness of four surrogate indexes of insulin resistance in middle-aged population in Hefei, China

OBJECTIVE

Previous study have shown that lipid accumulation product (LAP), visceral adiposity index (VAI), triglyceride/high-density lipoprotein cholesterol ratio (TG/HDL-C) and triglycerides/glucose index (TyG index) could be simple clinical indicators of insulin resistance (IR) based on anthropometric and/or biochemical parameters. However, the rational and preferred surrogate marker of IR in different population has yet to be validated. The aim of this study was evaluating the practicability of the LAP, VAI, TG/HDL-C, and TyG in predicting IR in middle-aged Chinese population.

METHODS

A cross-sectional study was conducted in 569 Chinese participants (mean age was 48.5; man 67.7%), and each participant completed a questionnaire survey, anthropometric measurement, and biochemical testing. One-way ANOVAs, Chi-squared test, Pearson's correlation, and multiple logistic regression were used to evaluate the association between VAI, LAP, TG/HDL-C, and TyG with IR. To correctly discriminate individuals with insulin resistance, a receiver operating characteristic (ROC) analysis was conducted for each evaluated variable and the overall diagnostic accuracy was quantified using the area under the ROC curve (AUC). The AUC of evaluated variables were compared using a nonparametric approach. The optimal cut-off points were determined by the Youden's index, and the corresponding sensitivity and specificity were provided.

RESULTS

Significant positive correlation was identified between HOMA-IR with TG/HDL-C (r = 0.306), VAI (r = 0.217), LAP (r = 0.381), and TyG (r = 0.371), respectively (all p < .001). After adjustment for potential confounders of IR, compared with the lowest tertiles, odds ratio (95% CI) having IR in the highest tertiles of TG/HDL-C, VAI, LAP and TyG were 6.07 (2.89-12.71), 10.89 (4.37-27.13), 4.68 (2.00-10.92), and 12.20 (5.04-29.56). The area under ROC curves to predict HOMA-diagnosed IR was 0.773 for TG/HDL-C, 0.767 for VAI, 0.806 for LAP, and 0.800 for TyG, respectively. Among those, LAP showed the greatest value of AUC [0.806 (0.763-0.850)] and highest specificity (0.804).

CONCLUSION

Compared with other indicators, the LAP and TyG are simple, relatively accurate, clinically available surrogate markers of insulin resistance in middle-aged population in Hefei, China. Among 4 evaluated parameters, the LAP have the highest specificity and the TyG have the highest sensitivity.Key MessagesLAP and TyG could be used as simple and alternative methods to identify the individuals at risk for insulin resistance.LAP and TyG have relatively high predictive ability in diagnosis of IR compared with VAI and TG/HDL-C.No significant difference is observed between LAP and TyG in the ability of predicting insulin resistance.

Sulfhydryl grafted palygorskite amendment with varying loading rates: Characteristic differences and dose-effect relationship for immobilizing soil Cd

Heavy metal contamination in agricultural soil and immobilization remediation have generated widespread concern in all areas of society. Sulfhydryl-functionalized materials as emerging amendments exhibit application potential, but the dose-effect relationship and immobilization mechanism are poorly understood. To understand the relationship between the immobilization effect and total sulfhydryl content, sulfhydryl-grafted palygorskite (SGP) with three sulfhydryl loading rates (0.88 mmol/g, 1.83 mmol/g, and 2.77 mmol/g) was prepared and characterized in the current study. The Cd immobilization efficiency and the dose-effect relationship were investigated via sorption in solutions, soil incubation, and field-scale wheat cultivation. ²⁹Si nuclear magnetic resonance, X-ray diffraction, differential scanning calorimetry, X-ray photoelectron spectroscopy, zeta potential, and potentiometric titration analyses confirmed that the sulfhydryl loading rates had little impact on the mineral structure but had a significant effect on the SGP surface properties. The sorption process of Cd²⁺ on SGP can be described by the 2nd order kinetic model and the Langmuir isotherm. The maximal sorption capacities had a linear relationship with the experimental sulfhydryl content in SGP. Meanwhile, SGP with three loading rates under different doses reduced available Cd concentrations in alkaline soil by 28.40 %-87.78 % in soil incubation and wheat grain Cd by 21.95 %-80.19 % in field-scale demonstration The relationship between immobilization efficiency and the total sulfhydryl group could be adequately described using the Michaelis-Menten equation. The sulfhydryl group was the key site for SGP amendments, which when added to the soil, reduced the bioavailability of soil Cd. Clarification of the dose-effect relationship will provide theoretical support for the accurate regulation of safe utilization of Cd-contaminated farmland.

[Attapulgite can improve yield and total ferulic acid content of Angelica sinensis by adjusting source-sink relationship]

Attapulgite(ATP), as a fertilizer slow-release agent and soil conditioner, has shown remarkable effect in improving the utilization rate of fertilizer and the yield and quality of agricultural products and Chinese medicinal materials. This study aims to explore the effect of ATP on the growth and root quality of Angelica sinensis. To be specific, Mingui 1 was used, and through the pot(soil culture) experiment in the Dao-di producing area, the effects of conventional chemical fertilizer added with ATP on the morphology, photosynthesis, soil respiration, and content of ferulic acid and volatile oil in roots of Mingui 1 were detected. The underlying mechanism was discussed from the perspective of source-sink relationship. The results showed that ATP, via the fertilizer slow-release effect, could meet the needs of A. sinensis for nutrients at the root expansion stage, improve the net photosynthetic rate of leaves and aboveground biomass of plants, and promote the transfer and accumulation of nutrients from the aboveground part(source) to the underground root(sink) in advance during the dry matter accumulation period of roots, so as to improve the root weight per plant. ATP can increase the content of total ferulic acid(the sum of free ferulic acid and coniferyl ferulate), the main effective component of Angelicae Sinensis Radix, by promoting the synthesis of ferulic acid in the roots and the transformation to coniferyl ferulate. However, it had little effect on the content of volatile oil. ATP had certain influence on soil respiration, which needs to be further explored from root activity, rhizosphere microorganisms, and soil microorganisms. This study can lay a basis for soil remediation and improvement and ecological cultivation of A. sinensis.

[History and present situation of seromuscular flap anastomosis in proximal gastrectomy]

With the increasing detection rate of early upper gastric cancer and adenocarcinoma of esophagogastric junction, the safety of proximal gastrectomy with clear indications has been verified, and function-preserving proximal gastrectomy has been widely used. However, proximal gastrectomy destructs the normal anatomical structure of esophagogastric junction, resulting in severe postoperative gastroesophageal reflux symptoms and seriously affecting the quality of life. Among various anti-reflux surgery methods, reconstruction of "cardiac valve" has always been the focus of relevant scholars because its similarity with the mechanism of normal anti-reflux. After years of development, evolution and optimization, the designed seromuscular flap anastomosis includes tunnel muscle flap anastomosis, Hatafuku valvuloplasty, single muscle flap anastomosis and double muscle flap anastomosis. The double muscle flap anastomosis has become a research hotspot because it shows good anti-reflux effect in clinical application. This paper reviews the history, research status and hot issues of seromuscular flap anastomosis of esophageal remnant stomach at home and abroad.

[Current status and progress in the standardized surgical management of specimens after radical gastric cancer surgery]

Standardized surgical management of postoperative specimens of gastric cancer is an important part of the standardized diagnosis and treatment of gastric cancer. It can reflect the accurate number and detailed distribution of lymph nodes in the specimen and lay the foundation for accurate and standardized pathological reports after surgery. Meanwhile, it can evaluate the scope of intraoperative lymph node dissection, the safety of cutting edge, and the standardization of surgery (principle of en-bloc dissection), which is an important means of surgical quality control. It also provides accurate research samples for further research and is an important way for young surgeons to train their clinical skills. The surgical management of postoperative specimens for gastric cancer needs to be standardized, including specimen processing personnel, processing flow, resection margin examination, lymph node sorting, measurement after specimen dissection, storage of biological specimens, documentation of recorded data, etc. The promotion of standardized surgical management of specimens after radical gastrectomy can promote the homogenization of gastric cancer surgical diagnosis and treatment in medical institutions and further promote the high-quality development of gastric cancer surgery in China.

Inhibitory Effect of Ursolic Acid on the Migration and Invasion of Doxorubicin-Resistant Breast Cancer

The cause of death in most breast cancer patients is disease metastasis and the occurrence of multidrug resistance (MDR). Ornithine decarboxylase (ODC), which is involved into multiple pathways, is closely related to carcinogenesis and development. Ursolic acid (UA), a natural triterpenoid compound, has been shown to reverse the MDR characteristics of tumor cells. However, the effect of UA on the invasion and metastasis of tumor cells with MDR is not known. Therefore, we investigated the effects of UA on invasion and metastasis, ODC-related polyamine metabolism, and MAPK-Erk-VEGF/MMP-9 signaling pathways in a doxorubicin-resistant breast cancer cell (MCF-7/ADR) model. The obtained results showed that UA significantly inhibited the adhesion and migration of MCF-7/ADR cells, and had higher affinities with key active cavity residues of ODC compared to the known inhibitor di-fluoro-methyl-ornithine (DFMO). UA could downregulate ODC, phosphorylated Erk (P-Erk), VEGF, and matrix metalloproteinase-9 (MMP-9) activity. Meanwhile, UA significantly reduced the content of metabolites of the polyamine metabolism. Furthermore, UA increased the intracellular accumulation of Dox in MCF-7/ADR cells. Taken together, UA can inhibit against tumor progression during the treatment of breast cancer with Dox, and possibly modulate the Erk-VEGF/MMP-9 signaling pathways and polyamine metabolism by targeting ODC to exert these effects.

Effectiveness and safety of Jiuwei Zhenxin granules for treating generalized anxiety disorder: A randomized controlled trial

BACKGROUND

Generalized anxiety disorder (GAD) is a chronic disorder characterized by excessive, pervasive, persistent worrying that is difficult to control. Jiuwei Zhenxin granules may be safer and more effective than non-benzodiazepine anti-anxiety drugs for treating GAD. This study aimed to assess the efficacy and safety of Jiuwei Zhenxin granules alone or in combination with the benzodiazepine alprazolam.

MATERIALS AND METHODS

A total of 710 patients were recruited from outpatient clinics and were randomly divided into two groups to receive Jiuwei Zhenxin granules (single drug group) or Jiuwei Zhenxin granules and alprazolam (combination group). The primary outcome was the response rate, which was defined as a ≥ 50% reduction from the baseline total score on the Hamilton Anxiety Scale (HAMA). Secondary outcome measures included mean changes in HAMA total score, psychological and somatic factors, Hamilton Depression Rating Scale total score, and SF-36 health survey score.

RESULTS

At 4 weeks after treatment, the single and combination treatment groups showed significant improvement in the HAMA total score and they did not differ significantly in response rate (77.58 vs. 79.17%) or rate of adverse drug reactions (16.22 vs. 16.07%).

CONCLUSION

Jiuwei Zhenxin granules are an effective, safe, and well-tolerated treatment against GAD. Combining them with alprazolam may not significantly improve efficacy.

CLINICAL TRIAL REGISTRATION

[www.ClinicalTrials.gov], identifier [CHICTR1800020095].

[Preparation of Mixed Metal Oxide/Carbon Composites and Its Adsorption Performance for Pb(Ⅱ)]

Layered double hydroxides, which can be synthesized from metal ions and their analogs, have abundant interlayer ions, surface functional groups, and adsorption characteristics that have been extensively studied. But the adsorption-desorption process may cause secondary pollution of the environment. In this study, the layered double hydroxides that adsorbed Congo red were converted into mixed metal oxide/carbon composites by a calcining carbonization method, and its adsorption performance for heavy metal ions Pb(Ⅱ) in aqueous solution was studied in detail. The results show that the prepared mixed metal oxide/carbon composites have a faster adsorption rate and higher adsorption capacity for Pb(Ⅱ). The adsorption capacity reached more than 150 mg·g^-1 in 30 min, and increased with the content of Mg²⁺ introduced into the layered double metal hydroxide, reaching a maximum of 368 mg·g^-1. The removal mechanism of Pb(Ⅱ) by mixed metal oxide/carbon composites was caused by the formation of insoluble Pb₃(CO₃) ₂(OH) ₂ on the surface. This research lays the foundation for the application of mixed metal oxide/carbon composites in the remediation of lead-containing soils.

[Application of modified Kamikawa anastomosis in digestive tract reconstruction after proximal gastrectomy]

Objective: Traditional Kamikawa anastomosis in digestive tract reconstruction after proximal gastrectomy can greatly decrease the anastomosis-related complications and reduce the incidence of reflux esophagitis, but its complexity limits the wide application. To decrease the complexity of Kamikawa anastomosis, the surgical team of Changzhi People's Hospital of Shanxi Changzhi Medical College improved this technique by using novel notion and reduced surgical procedures. This study aims to evaluate the efficacy and safety of modified Kamikawa anastomosis in digestive tract reconstruction after proximal gastrectomy. Methods: A descriptive cohort study was carried out. Case enrollment criteria: (1) upper gastric carcinoma or esophagogastric junction carcinoma without distant metastasis was confirmed by preoperative gastroscopic biopsy and imaging examination; (2) tumor diameter was less than 4 cm; (3) preoperative clinical staging was cT1-3N1M0. Exclusion criteria: (1) patients received preoperative neoadjuvant chemotherapy; (2) patients had severe heart or lung disease, or poor nutritional status so that they could not tolerate surgery. Clinical data of 25 patients with upper gastric carcinoma or esophagogastric junction carcinoma who underwent modified Kamikawa anastomosis in digestive tract reconstruction in Heji Hospital (8 cases) and Changzhi People's Hospital (17 cases) from April 2019 to December 2020 were retrospectively collected. Of 25 patients, 21 were male and 4 were female, with mean age of 63.0 (49 to 78) years; 3 underwent open surgery and 22 underwent laparoscopic surgery. The modified Kamikawa anastomosis was as follows: (1) the novel notion of total mesangial resection of the esophagogastric junction was applied to facilitate the thorough removal of lymph nodes and facilitate hand-sewn anastomosis and embedding; (2) the diameter of the anastomotic stoma was selected according to the diameter of the esophageal stump, between 2.5 and 3.5 cm, to reduce the occurrence of anastomotic stenosis; (3) an ultrasonic scalpel was used to incise the esophageal stump, which could not only prevent bleeding of the esophageal stump, but also closely seal the esophageal mucosa, muscle layer and serosa to prevent esophageal mucosa retraction; (4) barbed suture was used to suture the remnant stomach fundus and esophagus to fix the stomach fundus in order to reduce the cumbersome and difficult intermittent sutures in a small space; (5) two barbed sutures were used to continuously suture the front and back walls of the anastomosis and complete the suture and fixation of the muscle flap. Relevant indicators of surgical safety, postoperative complications (using the Clavien-Dindo classification), esophageal reflux symptoms and the occurrence of esophagitis (using Los Angeles classification) were analyzed. The gastroesophageal reflux disease (GERD) score, gastroscopy, multi-position digestive tract radiography during postoperative follow-up were used to evaluate the residual gastric motility and anti-reflux efficacy. Results: Modified Kamikawa anastomosis in digestive tract reconstruction after proximal gastrectomy was successfully performed in 25 patients. The surgical time was (5.8±1.8) hours, the intraoperative blood loss was (89.2±11.8) ml, and the average hospital stay was (13.8±2.9) days. Three cases (12.0%) developed postoperative anastomotic stenosis as Clavien-Dindo grade III and were healed after endoscopic dilation treatment. Postoperative upper gastrointestinal radiography showed 1 case (4.0%) with reflux symptoms as Clavien-Dindo grade I. Gastroscopy showed no signs of reflux esophagitis, and its Los Angeles classification was A grade. No anastomotic bleeding, local infection and death were found in all the patients. At postoperative 6-month of follow-up, GERD score showed no significant difference compared to pre-operation (2.7±0.6 vs. 2.4±1.0, t=-1.495, P=0.148). Conclusion: Modified Kamikawa anastomosis in digestive tract reconstruction after proximal gastrectomy is safe and feasible with good anti-reflux efficacy.

Fast and Highly Efficient Adsorption Removal of Toxic Pb(II) by a Reusable Porous Semi-IPN Hydrogel Based on Alginate and Poly(Vinyl Alcohol)

A porous semi-interpenetrating network (semi-IPN) hydrogel adsorbent with excellent adsorption properties and removal efficiency towards Pb(II) was prepared by a facile grafting polymerization reaction in aqueous medium using natural biopolymer sodium alginate (SA) as the main chains, sodium acrylate (NaA) as the monomers, and poly(vinyl alcohol) (PVA) as the semi-IPN component. FTIR, TGA and SEM analyses confirm that NaA monomers were grafted onto the macromolecular chains of SA, and PVA chains were interpenetrated and entangled with the crosslinked network. The incorporation of PVA facilitates to form pores on the surface of hydrogel adsorbent. The semi-IPN hydrogel containing 2 wt% of PVA exhibits high adsorption capacity and fast adsorption rate for Pb(II). The best adsorption capacity reaches 784.97 mg/g, and the optimal removal rate reaches 98.39% (adsorbent dosage, 2 g/L). In addition, the incorporation of PVA improved the gel strength of hydrogel, and the storage modulus of hydrogel increased by 19.4% after incorporating 2 wt% of PVA. The increase of gel strength facilitates to improve the reusability of hydrogel. After 5 times of regeneration, the adsorption capacity of SA-g-PNaA decreased by 23.2%, while the adsorption capacity of semi-IPN hydrogel only decreased by 10.8%. The adsorption kinetics of the hydrogel in the initial stage (the moment when the adsorbent contacts solution) and the second stage are fitted by segmentation. It is intriguing that the adsorption kinetics fits well with both pseudo-second-order kinetic model and pseudo-first-order model before 60 s, while only fits well with pseudo-second-order adsorption model in the whole adsorption process. The chemical complexing adsorption mainly contribute to the efficient capturing of Pb(II).

LncRNA LncOGD-1006 alleviates OGD-induced ischemic brain injury regulating apoptosis through miR-184-5p/CAAP1 axis

OBJECTIVE

This study aimed to explore the effect of long non-coding RNA (LncRNA) LncOGD-1006 to ischemic stroke and the possible mechanism.

MATERIALS AND METHODS

The primary brain microvascular endothelial cells (bEnd.3) of oxygen-glucose deprivation (OGD) was used as a mimic of ischemic stroke in vitro.

RESULTS

The results showed that LncOGD-1006 was upregulated in bEnd.3 after OGD-induced.

CONCLUSIONS

LncOGD-1006 might act as a ceRNA to inhibit apoptosis in bEnd.3 cells by targeting miR-184-5p/CAAP1 pathway.

[Current status of research on standardized management of specimens after radical gastrectomy for gastric cancer]

The quality control and standardization of procedures in radical gastrectomy for gastric cancer, especially the standardized processing of specimens after radical gastrectomy for gastric cancer, is very important. It is not only the basis of accurate pathological staging, but also the evidence of surgical quality and the original data of clinical research, which plays a pivotal role. The examination and classification of lymph nodes, specimens processing records, and data uploading and archiving after radical gastrectomy for gastric cancer are indispensable. It is necessary for surgeons to participate in the processing of surgical specimens. This article will combine the current research status and progress at home and abroad to review the standardized processing of specimens after radical gastrectomy for gastric cancer.

Synthesis and application of eco-friendly superabsorbent composites based on xanthan gum and semi-coke

An eco-friendly superabsorbent composites of xanthan gum-g-polyacrylic acid/semi-coke (XG-g-PAA/SC) were fabricated via grafting of polyacrylic acid onto the XG in the presence of SC. The obtained products were characterized in combination with Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA) and scanning electron microscopy (SEM). The result indicated that the SC interacted with the polymeric network by hydrogen bond or electrostatic interaction. The swelling ratio of the best sample XG-g-PAA/SC (15 wt%) in distilled water and 0.9 wt% NaCl solution was 410.8 and 61.5 g/g by optimizing the polymerization conditions. In addition, compared with the blank sample (only containing soil), it can be found that adding a certain amount of XG-g-PAA/SC can significantly improve the soil water retention efficiency, which can be further proved by the results of plant pot experiment. Based on the above excellent swelling capacity, water holding capacity and plant growth promoting performance, it can be inferred that the XG-g-PAA/SC is expected to become a water retaining agent or soil regulator for plant growth.

[Current status of anti-reflux surgery of proximal gastrectomy for esophagogastric junction tumor]

In recent years, the overall incidence of gastric cancer has been decreasing worldwide, while the incidence of the esophagogastric junction tumor is increasing year by year. With the progress of the diagnostic technology of upper gastrointestinal tumors and the gradual popularization of early cancer screening, the detection rate of early esophagogastric junction tumor keeps increasing. Therefore, in recent years, the clinical application of gastric function preserving surgery is gradually increasing. As an important part of the surgical treatment strategy of esophagogastric junction tumors, proximal gastrectomy has attracted more and more attention with the confirmation of oncological safety. Compared with total gastrectomy, patients after proximal gastrectomy have better nutritional status and quality of life. However, the high incidence of reflux esophagitis after traditional proximal gastrectomy has seriously affected the quality of life of patients, and also hindered the application of proximal gastrectomy in esophagogastric junction tumors. How to reduce the occurrence of reflux esophagitis after proximal gastrectomy by optimizing the method of digestive tract reconstruction has been a big challenge in clinical practice. This article reviews the current methods of anti-reflux surgery for proximal gastrectomy for esophagogastric junction tumors, aiming to provide a reference for choosing a reasonable anti-reflux surgery.

Genome-wide Analyses Identify a Novel Risk Locus for Nonsyndromic Cleft Palate

The 3 major subphenotypes observed in patients with nonsyndromic orofacial clefts (NSOFCs) are nonsyndromic cleft lip only (NSCLO), nonsyndromic cleft lip with palate (NSCLP), and nonsyndromic cleft palate only (NSCPO). However, the genetic architecture underlying NSCPO is largely unknown. Here we performed a 2-stage genome-wide association study (GWAS) on NSCPO and replication analyses of selected variants in other NSOFCs from the Chinese Han population. We identified a novel locus (15q24.3) and a known locus (1q32.2) where variants in or near the gene reached genome-wide significance (2.80 × 10^-13 < P < 1.72 × 10^-08) in a test for association with NSCPO in a case-control design. Although a variant from 15q24.3 was found to be significantly associated with both NSCPO and NSCLP, the direction of estimated effects on risk were opposite. Our functional annotation of the risk alleles within 15q24.3 coupled with previously established roles of the candidate genes within identified risk loci in periderm development, embryonic patterning, and/or regulation of cellular processes supports their involvement in palate development and the pathogenesis of cleft palate. Our study advances the understanding of the genetic basis of NSOFCs and provides novel insights into the pathogenesis of NSCPO.

Mesoporous silicate/carbon composites derived from dye-loaded palygorskite clay waste for efficient removal of organic contaminants

Palygorskite (Pal) is a natural abundant environment-friendly adsorbent that has shown high efficiency to decontaminate dye in water. However, the dye removal results in transformation of Pal to a very stable Maya Blue-like structure or waste Pal clay (WPal), which could not be easily regenerated by a commonly used desorption process. This paper presents a use of WPal as the precursor material to synthesize a highly-efficient mesoporous silicate/carbon composite adsorbent. The composite adsorbent has a large specific surface area (427.9 m²·g^-1), a high negative potential (-40.6 mV) and a mesoporous size (3.48 nm). This adsorbent shows almost complete removal of tetracycline (TC), crystal violet (CV) and methylene blue (MB) (initial concentration, 200 mg·L^-1) with the optimal adsorption capacities of 319.8 mg·g^-1, 244.4 mg·g^-1 and 281.7 mg·g^-1, respectively. The active -Si-O^- adsorption sites produced by the breaking of inert Si-O-Si (or M) bonds and the electrostatic interactions of negatively charged adsorbents to adsorbates play a major role in the adsorption process. Adsorption capacities of the developed composite are significantly higher than that of Pal, WPal and hydrothermally treated WPal (HWPal). Results demonstrate that the composite adsorbents have high potential in decontamination of organics in water efficiently.

Folate Receptor-Targeting and Reactive Oxygen Species-Responsive Liposomal Formulation of Methotrexate for Treatment of Rheumatoid Arthritis

Multifunctional nanomedicines with active targeting and stimuli-responsive drug release function utilizing pathophysiological features of the disease are regarded as an effective strategy for treatment of rheumatoid arthritis (RA). Under the inflammatory environment of RA, activated macrophages revealed increased expression of folate receptor and elevated intracellular reactive oxygen species (ROS) level. In this study, we successfully conjugated folate to polyethylene glycol 100 monostearate as film-forming material and further prepared methotrexate (MTX) and catalase (CAT) co-encapsulated liposomes, herein, shortened to FOL-MTX&CAT-L, that could actively target to activated macrophages. Thereafter, elevated intracellular hydrogen peroxide, the main source of ROS, diffused into liposomes and encapsulated CAT catalyzed the decomposition of hydrogen peroxide into oxygen and water. Continuous oxygen-generation inside liposomes would eventually disorganize its structure and release the encapsulated MTX. We characterized the in vitro drug release, cellular uptake and cytotoxicity studies as well as in vivo pharmacokinetics, biodistribution, therapeutic efficacy and safety studies of FOL-MTX&CAT-L. In vitro results revealed that FOL-MTX&CAT-L possessed sufficient ROS-sensitive drug release, displayed an improved cellular uptake through folate-mediated endocytosis and exhibited a higher cytotoxic effect on activated RAW264.7 cells. Moreover, in vivo results showed prolonged blood circulation time of PEGylated liposomes, enhanced accumulation of MTX in inflamed joints of collagen-induced arthritis (CIA) mice, reinforced therapeutic efficacy and minimal toxicity toward major organs. These results imply that FOL-MTX&CAT-L may be used as an effective nanomedicine system for RA treatment.

Heterologous expression and characterization of a novel subtilisin-like protease from a thermophilic Thermus thermophilus HB8

Subtilisins are a family of serine proteases used widely throughout the detergent, leather and food industries, with the identification and development of new enzymes holding much potential value. Thermus thermophilus HB8 was examined for serine proteases and found TTHA0724 gene. Sequence analysis of this putative serine protease placed it within the subtilisin family. To obtain active T. thermophilus HB8 subtilisins, three genes encoding prepro-subtilisin, pro-subtilisin and mature-subtilisin were cloned and expressed in Escherichia coli Transetta (DE3). Although direct expression of the mature-subtilisin gene was found to produce inactive inclusion bodies, expression of the pro-subtilisin gene resulted in active mature-subtilisin, indicating that the pro-sequence of translated pro-subtilisin underwent autoproteolysis. The resulting mature-subtilisin exhibited maximal activity between 65 and 85 °C at pH 7.5. The mature-subtilisin showed good stability, maintaining 50% activity after 48 h at 75 °C and >78% activity across the pH range 5.0-9.5. Furthermore, the mature-subtilisin demonstrated broad substrate specificity, with no requirement for the presence of metal ions which are essential for other subtilisin enzymes. Despite this Cu²⁺ was able to increase enzyme activity, while Ca²⁺ partially inhibited the activity. These properties suggest that T. thermophilus HB8 mature-subtilisin has potential value in its application in many industries.

Reversal of multidrug resistance in breast cancer cells by a combination of ursolic acid with doxorubicin

Multidrug resistance (MDR) has seriously affected or hindered the effect of chemotherapy. Ursolic acid (UA) as a natural compound exhibits a number of potential biological effects including antitumor. Searching for the reversal agents from the natural products has been an effective strategy recently applied in overcoming the MDR. So in this study, the reversal effect of UA on the MDR and involved mechanisms were investigated via a multidrug-resistant MCF-7/ADR cells model and ultrahigh performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) analytical methods. The synergistic effects were yielded by the combination of UA and Dox based on the investigation of the intracellular accumulation, the P-glycoprotein (P-gp) mediated transport, the energy metabolism including glycolysis, tricarboxylic acid (TCA) cycle, and glutamine metabolism as well as related amino acid metabolism. Obtained results showed that the UA could increase amount of doxorubicin (Dox) entering the cell to accumulate in nuclei, decrease the efflux ratio of digoxin comparable to the effects of the known inhibitor verapamil by acting as a P-gp substrate, decrease the content of intracellular alanine, lactate, pyruvate, glucose, α-ketoglutarate, glutamate, glutamine, aspartate, serine, and glycine. Taken together, inhibition of P-gp function and disruption of the metabolism of energy and related amino acids could be the key mechanisms by which UA could reverse the MDR. The findings also indicated that UA could be a potential alternative adjuvant antitumour herbal medicine to resensitize cells with MDR to chemotherapeutic agents.

From waste hot-pot oil as carbon precursor to development of recyclable attapulgite/carbon composites for wastewater treatment

The utilization of waste products as valuable materials was a technical imperative for waste management. In this study, the cost-effective attapulgite/carbon (APT/C) composite was developed for wastewater treatment using waste hot-pot oil as a carbon precursor through a facile one-step calcination process. The APT/C composite prepared at 300°C exhibited the excellent adsorption capacity and rapid equilibrium rate over a broad pH range for the removal of various pollutants. More importantly, the removal ratios of the composites toward Methyl Violet and tetracycline still remained 77.6% and 60.2% of the initial adsorption capacity after ten adsorption-regeneration cycles via a facile thermal regeneration strategy, respectively. Beyond all doubt, this research provided a feasible and economical way for the sustainable utilization of waste hot-pot oil in wastewater treatment, achieving the concept of disposal waste with waste and recycling.

Liquid extraction surface analysis nanospray electrospray ionization based lipidomics for in situ analysis of tumor cells with multidrug resistance

RATIONALE

Multidrug resistance (MDR) occurs frequently and is a major challenge in tumor treatment. The lipid composition in the cell membrane and the redox balance are closely associated with the development of MDR. Liquid extraction surface analysis in combination with mass spectrometry (LESA-MS) has the characteristics of minimal sample preparation, rapid analysis, high sensitivity and high throughput, and has obtained wide applications.

METHODS

LESA-MS was employed to in situ determine the lipids and other specific metabolites of intact MCF-7/ADR cells (adriamycin-resistant breast cancer cells) and its parental MCF-7/S cells grown on a glass slide. In situ atomic force microscopy was used to observe the morphology of tumor cells before and after extraction. Multivariate statistical analysis was used to investigate the potential lipid biomarkers correlated with the MDR. Moreover, the cell membrane fluidity and potential were determined.

RESULTS

The changes in the level of the lipids were closely correlated with the multidrug resistance of MCF-7/S cells. Moreover, lower cell membrane fluidity and higher cell membrane potential were observed and thus demonstrated the changes in the cell membrane induced by multidrug resistance. Also, the ratios of GSH/GSSG, ATP/ADP and ATP/AMP were significantly higher in MCF-7/ADR cells relative to MCF-7/S cells.

CONCLUSIONS

Lower cell membrane fluidity and higher cell membrane potential caused by the changes in lipid compositions, enhanced anti-oxidative ability and energy generation were involved in the development of the MDR. The specific alterations identified in this study may provide more information for overcoming MDR.

Targeted delivery of antigen to intestinal dendritic cells induces oral tolerance and prevents autoimmune diabetes in NOD mice

AIMS/HYPOTHESIS

The intestinal immune system is an ideal target to induce immune tolerance physiologically. However, the efficiency of oral protein antigen delivery is limited by degradation of the antigen in the gastrointestinal tract and poor uptake by antigen-presenting cells. Gut dendritic cells (DCs) are professional antigen-presenting cells that are prone to inducing antigen-specific immune tolerance. In this study, we delivered the antigen heat shock protein 65-6×P277 (H6P) directly to the gut DCs of NOD mice through oral vaccination with H6P-loaded targeting nanoparticles (NPs), and investigated the ability of this antigen to induce immune tolerance to prevent autoimmune diabetes in NOD mice.

METHODS

A targeting NP delivery system was developed to encapsulate H6P, and the ability of this system to protect and facilitate H6P delivery to gut DCs was assessed. NOD mice were immunised with H6P-loaded targeting NPs orally once a week for 7 weeks and the onset of diabetes was assessed by monitoring blood glucose levels.

RESULTS

H6P-loaded targeting NPs protected the encapsulated H6P from degradation in the gastrointestinal tract environment and significantly increased the uptake of H6P by DCs in the gut Peyer's patches (4.1 times higher uptake compared with the control H6P solution group). Oral vaccination with H6P-loaded targeting NPs induced antigen-specific T cell tolerance and prevented diabetes in 100% of NOD mice. Immune deviation (T helper [Th]1 to Th2) and CD4⁺CD25⁺FOXP3⁺ regulatory T cells were found to participate in the induction of immune tolerance.

CONCLUSIONS/INTERPRETATION

In this study, we successfully induced antigen-specific T cell tolerance and prevented the onset of diabetes in NOD mice. To our knowledge, this is the first attempt at delivering antigen to gut DCs using targeting NPs to induce T cell tolerance.

A multifunctional nanoparticle constructed with a detachable albumin outer shell and a redox-sensitive inner core for efficient siRNA delivery to hepatocellular carcinoma cells

Successful delivery of small interfering RNA (siRNA) into the cytoplasm of target cells relies on biocompatible and efficient vectors. In this study, a novel multifunctional core/shell nanoparticle [CS-SS-9R/BSA-c(RGDyK)] was developed to effectively deliver siVEGF to hepatocellular carcinoma cells (Bel-7402 cells). To improve the gene payload and transfection efficiency, a positively charged inner core (CS-SS-9R) was constructed by grafting nona-arginine (9R) onto chitosan (CS) using disulphide bonds. The negatively charged outer shell [BSA-c(RGDyK)] assembled on the surface of the inner core by electrostatic forces that shielded high cationic charges and provided improved targeting. The protein outer shell gradually detached from the inner core in the acidic lysosomal environment, leaving the cationic inner core exposed in order to escape from lysosomes. The nanoparticles were capable of delivering siVEGF into Bel-7402 cells via integrin receptor-mediated endocytosis. Successful lysosomal escape of the inner core and the rapid release of siVEGF into the cytoplasm resulted in a 78.9% decrease in VEGF expression and 81.2% inhibition of tumour cell proliferation. In conclusion, this nanoparticle is responsive to the intracellular environment and accurately delivered siRNA into the cytoplasm, providing a safe and highly efficient gene delivery strategy for cancer therapy.

Cell metabolomics reveals the neurotoxicity mechanism of cadmium in PC12 cells

The heavy metals such as cadmium (Cd) can induce neurotoxicity. Extensive studies about the effects of Cd on human health have been reported, however, a systematic investigation on the molecular mechanisms of the effects of Cd on central nervous system is still needed. In this paper, the neuronal PC-12 cells were treated with a series of concentrations of CdCl₂ for 48h. Then the cytotoxicity was evaluated by MTT (3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide) assay. The IC₁₅ value (15% inhibiting concentration) was selected for further mechanism studies. After PC-12 cells incubated with CdCl₂ at a dose of IC₁₅ for 48h, the intracellular and extracellular metabolites were profiled using ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS)-based cell metabolomics approach. As found, the effects of the heavy metal Cd produced on the PC-12 cell viability were dose-dependent. The metabolic changes were involved in the glycolysis and gluconeogenesis, biopterin metabolism, tryptophan metabolism, tyrosine metabolism, glycerophospholipid metabolism, and fatty acids beta-oxidation. These could cause the perturbation of cell membrane, redox balance, energy supply, cellular detoxification, further affecting the cellular proliferation and apoptosis and other cellular activities.

Metabolomics analysis of multidrug-resistant breast cancer cellsin vitrousing methyl-tert-butyl ether method

MTBE-based cellular lipidomics to investigate the mechanisms of multidrug resistance of breast cancer.

Dendritic Cells Targeting and pH-Responsive Multi-layered Nanocomplexes for Smart Delivery of DNA Vaccines

Specific and effective delivery of DNA vaccines into dendritic cells (DCs) to express antigens is a precondition for induction of immune responses. Construction of a new DNA vaccine delivery system with the ability of programmed gene transfection may achieve this objective. In this study, we successfully integrated dendritic lipopeptide, charge-reversible polymer, and APC-targeted material into DNA vaccine delivery system through layer-by-layer (LBL) assembly. By the means of adjusting the weight ratios and concentration ratios of components, stable complexes were formulated with a particle size of 256.8 ± 10.7 nm and zeta potential of 25.1 ± 2.3 mV. Moreover, this DNA vaccine delivery system could achieve specific delivery into DCs, high transfection efficiency and low cytotoxicity, holding great promise for immunotherapy.

SuhB Regulates the Motile-Sessile Switch in Pseudomonas aeruginosa through the Gac/Rsm Pathway and c-di-GMP Signaling

Many Pseudomonas aeruginosa virulence traits that contribute to human infections are accepted as being associated with its environmental lifestyle. Therefore, identifying the molecular mechanisms that govern the lifestyle choice is of high significance. We previously reported that a mutation in suhB results in a decrease in swimming motility and increased biofilm formation compared to the wild-type strain. Yet, little is known about how this occurs. In this study, we demonstrated that SuhB inversely regulates motility and biofilm formation through the GacA-RsmY/Z-RsmA cascade. Mutations in gacA or the two small RNAs rsmY/rsmZ, or overproduction of the RsmA protein essentially rescued the motility defect of the suhB mutant. Additionally, we identified a c-di-GMP mediated mechanism for SuhB regulation of motility and biofilm formation. We showed that the ΔsuhB mutant displayed elevated levels of c-di-GMP, and the ΔsuhB motility and biofilm phenotypes could be switched by artificially decreasing c-di-GMP levels. Further experiments led to the identification of the diguanylate cyclase GcbA responsible for regulating the c-di-GMP concentration in ΔsuhB and hence the switch between planktonic and surface-associated growth. Together, our results demonstrate a novel mechanism for SuhB regulation of the lifestyle transition via the Gac/Rsm and c-di-GMP signaling networks in P. aeruginosa.

Fabrication of CMC-g-PAM Superporous Polymer Monoliths via Eco-Friendly Pickering-MIPEs for Superior Adsorption of Methyl Violet and Methylene Blue

A series of superporous carboxymethylcellulose-graft-poly(acrylamide)/palygorskite (CMC-g-PAM/Pal) polymer monoliths presenting interconnected pore structure and excellent adsorption properties were prepared by one-step free-radical grafting polymerization reaction of CMC and acrylamide (AM) in the oil-in-water (O/W) Pickering-medium internal phase emulsions (Pickering-MIPEs) composed of non-toxic edible oil as a dispersion phase and natural Pal nanorods as stabilizers. The effects of Pal dosage, AM dosage, and co-surfactant Tween-20 (T-20) on the pore structures of the monoliths were studied. It was revealed that the well-defined pores were formed when the dosages of Pal and T-20 are 9–14 and 3%, respectively. The porous monolith can rapidly adsorb 1,585 mg/g of methyl violet (MV) and 1,625 mg/g of methylene blue (MB). After the monolith was regenerated by adsorption-desorption process for five times, the adsorption capacities still reached 92.1% (for MV) and 93.5% (for MB) of the initial maximum adsorption capacities. The adsorption process was fitted with Langmuir adsorption isotherm model and pseudo-second-order adsorption kinetic model very well, which indicate that mono-layer chemical adsorption mainly contribute to the high-capacity adsorption for dyes. The superporous polymer monolith prepared from eco-friendly Pickering-MIPEs shows good adsorption capacity and fast adsorption rate, which is potential adsorbent for the decontamination of dye-containing wastewater.

A rationally designed peptide IA-2-P2 against type 1 diabetes in streptozotocin-induced diabetic mice

Recent studies have investigated the potential of type 1 diabetes mellitus-related autoantigens, such as heat shock protein 60, to induce immunological tolerance or to suppress the immune response. A functional 24-residue peptide derived from heat shock protein 60 (P277) has shown anti-type 1 diabetes mellitus potential in experimental animals and in clinical studies, but it also carries a potential atherogenic effect. In this study, we have modified P277 to retain an anti-type 1 diabetes mellitus effect and minimize the atherogenic potential by replacing the P277 B epitope with another diabetes-associated autoantigen, insulinoma antigen-2 (IA-2), to create the fusion peptide IA-2-P2. In streptozotocin-induced diabetic C57BL/6J mice, the IA-2-P2 peptide displayed similar anti-diabetic effects to the control P277 peptide. Also, the IA-2-P2 peptide did not show atherogenic activity in a rabbit model. Our findings indicate the potential of IA-2-P2 as a promising vaccine against type 1 diabetes mellitus.

Sequence analysis and functional characterization of full-length hepatitis B virus genomes from Korean cirrhotic patients with or without liver cancer

This study aimed to identify and characterize mutations in the hepatitis B virus (HBV) genome associated with advanced liver diseases. The 3.2-kb HBV genome of the C2 subgenotype was amplified from sera of 18 cirrhotic Korean patients with (10) or without (8) hepatocellular carcinoma (HCC), and two clones per patient were characterized by transient transfection experiments in human hepatoma cells. While A1762T/G1764A core promoter mutations were highly prevalent in both groups, the G1896A precore mutation to abolish hepatitis B e antigen (HBeAg) expression was more common in HCC clones (55% vs. 20%). High replication capacity was mostly found in HCC clones and associated with core promoter mutations, whereas more non-HCC clones harbored a nonfunctional core gene (34% vs. 8%). Large in-frame deletions in the preS region were found in 60% of HCC clones and 38% of non-HCC clones. They removed the first 11 residues of large envelope protein or impaired small envelope protein expression, or deleted a neutralizing epitope in the preS2 domain. Additional point mutations prevented middle envelope protein expression, or caused nonsense mutations in the preS or S region to truncate large and/or small envelope protein. Consequently, many clones were unable to express or secrete hepatitis B surface antigen (HBsAg). In conclusion, mutations associated with the advanced stage of chronic HBV infection are complex and diverse. Host immune pressure most likely selected for mutations in the HBV genome to abolish or reduce HBeAg or HBsAg production, to enhance genome replication, or to escape neutralizing antibodies. Some of these mutations may contribute to liver cirrhosis or HCC development.

The Envelope Gene of Hepatitis B Virus Is Implicated in Both Differential Virion Secretion and Genome Replication Capacities between Genotype B and Genotype C Isolates

Chronic infection by hepatitis B virus (HBV) genotype C is associated with a prolonged replicative phase and an increased risk of liver cancer, compared with genotype B infection. We previously found lower replication capacity but more efficient virion secretion by genotype C than genotype B isolates. Virion secretion requires interaction between core particles and ENVELOPE proteins. In the present study, chimeric constructs between genotype B and genotype C clones were generated to identify the structural basis for differential virion secretion. In addition to dimeric constructs, we also employed 1.1mer constructs, where the cytomegalovirus (CMV) promoter drove pregenomic RNA transcription. Through transient transfection experiments in Huh7 cells, we found that exchanging the entire envelope gene or just its S region could enhance virion secretion by genotype B clones while diminishing virion secretion by genotype C. Site-directed mutagenesis established the contribution of genotype-specific divergence at codons 108 and 115 in the preS1 region, as well as codon 126 in the S region, to differential virion secretion. Surprisingly, exchanging the envelope gene or just its S region, but not the core gene or 3′ S region, could markedly increase intracellular replicative DNA for genotype C clones but diminish that for genotype B, although the underlying mechanism remains to be clarified.

Targeted delivery of doxorubicin by nano-loaded mesenchymal stem cells for lung melanoma metastases therapy

Poor antigenic presentation of tumor tissues and a lack of specific targets currently limit the success of nanoparticle delivery system. Cellular carrier technique has been recently explored extensively as a substitutive or supplement for traditional targeting delivery system. Here, we demonstrate the usage of mesenchymal stem cells (MSCs) loaded with doxorubicin containing polymer nanoparticles in pulmonary melanoma metastases therapy, as a modified technique of targeted delivery system. The characterizations of prepared nanoparticles and MSCs sensitivity to DOX and PLGA-DOX were measured. In vitro tumor tropism, and in vivo distributions of nanoparticles loaded MSCs were also investigated. The findings have demonstrated that, the modified system not only integrates the controlled-release property of nanoparticles but also exhibits tumor tropism and penetrative characteristics of MSCs. Furthermore, the in vitro and in vivo anti-tumor study has demonstrated that drug loaded MSCs had potent efficacy in lung melanoma metastases treatment.

Differential regulation of hepatitis B virus core protein expression and genome replication by a small upstream open reading frame and naturally occurring mutations in the precore region

Hepatitis B virus (HBV) transcribes two subsets of 3.5-kb RNAs: precore RNA for hepatitis B e antigen (HBeAg) expression, and pregenomic RNA for core and P protein translation as well as genome replication. HBeAg expression could be prevented by mutations in the precore region, while an upstream open reading frame (uORF) has been proposed as a negative regulator of core protein translation. We employed replication competent HBV DNA constructs and transient transfection experiments in Huh7 cells to verify the uORF effect and to explore the alternative function of precore RNA. Optimized Kozak sequence for the uORF or extra ATG codons as present in some HBV genotypes reduced core protein expression. G1896A nonsense mutation promoted more efficient core protein expression than mutated precore ATG, while a +1 frameshift mutation was ineffective. In conclusion, various HBeAg-negative precore mutations and mutations affecting uORF differentially regulate core protein expression and genome replication.

From illite/smectite clay to mesoporous silicate adsorbent for efficient removal of chlortetracycline from water

A series of mesoporous silicate adsorbents with superior adsorption performance for hazardous chlortetracycline (CTC) were sucessfully prepared via a facile one-pot hydrothermal reaction using low-cost illite/smectite (IS) clay, sodium silicate and magnesium sulfate as the starting materials. In this process, IS clay was "teared up" and then "rebuilt" as new porous silicate adsorbent with high specific surface area of 363.52m²/g (about 8.7 folds higher than that of IS clay) and very negative Zeta potential (-34.5mV). The inert SiOSi (Mg, Al) bonds in crystal framework of IS were broken to form Si(Al) O^- groups with good adsorption activity, which greatly increased the adsorption sites served for holding much CTC molecules. Systematic evaluation on adsorption properties reveals the optimal silicate adsorbent can adsorb 408.81mg/g of CTC (only 159.7mg/g for raw IS clay) and remove 99.3% (only 46.5% for raw IS clay) of CTC from 100mg/L initial solution (pH3.51; adsorption temperature 30°C; adsorbent dosage, 3g/L). The adsorption behaviors of CTC onto the adsorbent follows the Langmuir isotherm model, Temkin equation and pseudo second-order kinetic model. The mesopore adsorption, electrostatic attraction and chemical association mainly contribute to the enhanced adsorption properties. As a whole, the high-efficient silicate adsorbent could be candidates to remove CTC from the wastewater with high amounts of CTC.