Electrochemically controlled rectification in symmetric single-molecule junctions.

Single-molecule electrochemical science has advanced over the past decades and now extends well beyond molecular imaging, to molecular electronics functions such as rectification and amplification. Rectification is conceptually the simplest but has involved mostly challenging chemical synthesis of asymmetric molecular structures or asymmetric materials and geometry of the two enclosing electrodes. Here we propose an experimental and theoretical strategy for building and tuning in situ (in operando) rectification in two symmetric molecular structures in electrochemical environment. The molecules were designed to conduct electronically via either their lowest unoccupied molecular orbital (LUMO; electron transfer) or highest occupied molecular orbital (HOMO; "hole transfer"). We used a bipotentiostat to control separately the electrochemical potential of the tip and substrate electrodes of an electrochemical scanning tunneling microscope (EC-STM), which leads to independent energy alignment of the STM tip, the molecule, and the STM substrate. By creating an asymmetric energy alignment, we observed single-molecule rectification of each molecule within a voltage range of ±0.5 V. By varying both the dominating charge transporting LUMO or HOMO energy and the electrolyte concentration, we achieved tuning of the polarity as well as the amplitude of the rectification. We have extended an earlier proposed theory that predicts electrolyte-controlled rectification to rationalize all the observed in situ rectification features and found excellent agreement between theory and experiments. Our study thus offers a way toward building controllable single-molecule rectifying devices without involving asymmetric molecular structures.

Synaptotagmin 1 oligomerization via the juxtamembrane linker regulates spontaneous and evoked neurotransmitter release.

Synaptotagmin 1 (syt1) is a Ca2+ sensor that regulates synaptic vesicle exocytosis. Cell-based experiments suggest that syt1 functions as a multimer; however, biochemical and electron microscopy studies have yielded contradictory findings regarding putative self-association. Here, we performed dynamic light scattering on syt1 in solution, followed by electron microscopy, and we used atomic force microscopy to study syt1 self-association on supported lipid bilayers under aqueous conditions. Ring-like multimers were clearly observed. Multimerization was enhanced by Ca2+ and required anionic phospholipids. Large ring-like structures (∼180 nm) were reduced to smaller rings (∼30 nm) upon neutralization of a cluster of juxtamembrane lysine residues; further substitution of residues in the second C2-domain completely abolished self-association. When expressed in neurons, syt1 mutants with graded reductions in self-association activity exhibited concomitant reductions in 1) clamping spontaneous release and 2) triggering and synchronizing evoked release. Thus, the juxtamembrane linker of syt1 plays a crucial role in exocytosis by mediating multimerization.

Applying the extended parallel process model to understand households' responses to tornado and earthquake risks in Oklahoma.

Oklahoma is a multihazard environment where both natural (e.g., tornadoes) and technological hazards (e.g., induced seismicity) are significant, making Oklahoma a unique setting to better understand how to manage and prepare for multiple hazards. While studies have attempted to understand drivers of hazard adjustments, few have focused on the overall number of adjustments undertaken instead of individual adjustments or adjustments in a multihazard environment. To address these gaps, we employ a survey sample of 866 households in Oklahoma to understand households' danger control responses (protective hazard adjustments) for tornado and earthquake risks in Oklahoma. We apply the extended parallel processing model (EPPM) to categorize respondents according to their relative level of perceived threat and efficacy of protective actions in predicting the number of hazard adjustments they intend to or have adopted in response to tornadoes and induced earthquakes. In line with the EPPM, we found that households have the highest number of danger control responses when their perceived threat and efficacy are both high. Counter to the EPPM literature, we found low threat coupled with high efficacy moved some individuals toward the adoption of danger control responses in response to both tornadoes and earthquakes. When households have high efficacy, threat appraisals matter in tornado danger control responses but not in earthquake danger control responses. This EPPM categorization opens new research approaches for studies of natural and technological hazards. This study also provides information for local officials and emergency managers making mitigation and preparedness investments and policies.

An Exo III-powered closed-loop DNA circuit architecture for biosensing/imaging.

With their regulated Boolean logic operations in vitro and in vivo, DNA logic circuits have shown great promise for target recognition and disease diagnosis. However, significant obstacles must be overcome to improve their operational efficiency and broaden their range of applications. In this study, we propose an Exo III-powered closed-loop DNA circuit (ECDC) architecture that integrates four highly efficient AND logic gates. The ECDC utilizes Exo III as the sole enzyme-activated actuator, simplifying the circuit design and ensuring optimal performance. Moreover, the use of Exo III enables a self-feedback (autocatalytic) mechanism in the dynamic switching between AND logic gates within this circulating logic circuit. After validating the signal flow and examining the impact of each AND logic gate on the regulation of the circuit, we demonstrate the intelligent determination of miR-21 using the carefully designed ECDC architecture in vitro. The proposed ECDC exhibits a linear detection range for miR-21 from 0 to 300 nM, with a limit of detection (LOD) of approximately 0.01 nM, surpassing most reported methods. It also shows excellent selectivity for miR-21 detection and holds potential for identifying and imaging live cancer cells. This study presents a practical and efficient strategy for monitoring various nucleic acid-based biomarkers in vitro and in vivo through specific sequence modifications, offering significant potential for early cancer diagnosis, bioanalysis, and prognostic clinical applications.

Improving aromatic higher alcohol acetates in wines by co-fermentation of Pichia kluyveri and Saccharomyces cerevisiae: growth interaction and amino acid competition.

BACKGROUND: Higher alcohol acetates (HAAs) are potent aroma-active esters that impart desirable fruity and floral aromas. However, the conversion of higher alcohol precursors into HAAs is extremely low in winemaking. To investigate the underlying yeast-yeast interaction on targeted improvement of aromatic HAAs, we evaluated fermentation activity, cell viability, amino acid consumption and HAA production when Pichia kluyveri and Saccharomyces cerevisiae were inoculated concurrently or sequentially. RESULTS: Pichia kluyveri PK-21 possessed the ability to survive and increased HAA level up to 5.2-fold in mixed fermentation. Such an increment may benefit from the efficient conversion of higher alcohol precursors into HAAs (>27-fold higher than S. cerevisiae). During mixed fermentation, the two yeasts exhibited crucial interactions regarding cell growth and amino acid competition. Saccharomyces cerevisiae dominated over the co-inoculated P. kluyveri by efficient uptake of amino acids and biomass production. However, this dominance decreased in sequential fermentation, where P. kluyveri growth increased due to the consumption of preferred amino acids prior to S. cerevisiae. Pearson correlation analysis indicated that phenylalanine and aspartic acid may act as positive amino acids in boosting P. kluyveri growth and HAA production. Laboratory-scale winemaking validated the fermentation performance of P. kluyveri in sequential inoculum, resulting in a balanced aroma profile with enhanced floral and tropical fruity characteristics in the final wines. CONCLUSION: This study proposes a microbial, non-genetically engineered approach for targeted increase of HAA production in winemaking and the findings provide new insights into yeast-yeast interactions. © 2024 Society of Chemical Industry.

CS/CoFe2O4 nanocomposite as a high-effective and steady chainmail catalyst for tetracycline degradation with peroxymonosulfate activation: performance and mechanism.

Tetracycline becomes a crucial measure for managing and treating communicable diseases in both human and animal sectors due to its beneficial antibacterial properties and cost-effectiveness. However, it is important not to trivialize the associated concerns of environmental contamination following the antibiotic's application. In this study, cobalt ferrate (CoFe2O4) nanoparticles were loaded into chitosan (CS), which can avoid the agglomeration problem caused by high surface energy and thus improve the catalytic performance of cobalt ferrate. And it can avoid the problem of secondary contamination caused by the massive leaching of metal ions. The resulting product was used as a catalyst to activate peroxymonosulfate (PMS) for the degradation of tetracycline (TC). To determine the potential effects on TC degradation, various factors such as PMS dosing, catalyst dosing, TC concentration, initial solution pH, temperature, and inorganic anions (Cl-, H2PO4- and HCO3-) were investigated. The CS/CoFe2O4/PMS system exhibited superior performance compared to the CoFe2O4-catalyzed PMS system alone, achieving a 92.75% TC removal within 120 min. The catalyst displayed high stability during the recycling process, with the efficiency observed after five uses remaining at a stable 73.1%, and only minor leaching of dissolved metal ions from the catalyst. This confirms the high stability of the catalyst. The activation mechanism study showed that there are free radical and non-free radical pathways in the reaction system to degrade TC together, and SO4•- and 1O2 are the primary reactive oxygen radicals involved in the reaction, allowing for effective treatment of contaminated water by TC.

Enhanced π-π Stacking between Dipole-Bearing Single Molecules Revealed by Conductance Measurement.

Dipoles are widely involved in π-π interactions and are central to many chemical and biological functions, but their influence on the strength of π-π interactions remains unclear. Here, we report a study of π-π interaction between azulene-based, polar single molecules and between naphthalene-based, nonpolar single molecules. By performing scanning tunneling microscopy break junction measurements of single-molecule conductance, we show that the π-stacked dimers formed by the azulene-based, polar aromatic structures feature higher electrical conductivity and mechanical stability than those formed by the naphthalene-based, nonpolar molecules. Mechanical control of π-π interactions in both rotational and translational motion reveals a sensitive dependence of the stacking strength on relative alignment between the dipoles. The antiparallel alignment of the dipoles was found to be the optimal stacking configuration that underpins the observed enhancement of π-π stacking between azulene-based single molecules. Density functional theory calculations further explained the observed enhancement of stacking strength and the corresponding charge transport efficiency. Our experimental and theoretical results show that the antiparallel alignment of the dipole moments significantly enhances the electronic coupling and mechanical stability of π-π stacking. In addition, in the formation of single-molecule junctions, the azulene group was experimentally and theoretically proved to form a Au-π contact with electrodes with high charge transport efficiency. This paper provides evidence and interpretation of the role of dipoles in π-π interactions at the single-molecule level and offers new insights into potential applications in supramolecular devices.

Leveraging Ligand and Composition Effects: Morphology-Tailorable Pt-Bi Bimetallic Aerogels for Enhanced (Photo-)Electrocatalysis.

Metal aerogels (MAs) are emerging porous materials displaying unprecedented potential in catalysis, sensing, plasmonic technologies, etc. However, the lack of efficient regulation of their nano-building blocks (NBBs) remains a big hurdle that hampers the in-depth investigation and performance enhancement. Here, by harmonizing composition and ligand effects, Pt- and Bi-based single- and bimetallic aerogels bearing NBBs of controlled dimensions and shapes are obtained by facilely tuning the metal precursors and the applied ligands. Particularly, by further modulating the electronic and optic properties of the aerogels via adjusting the content of the catalytically active Pt component and the semiconducting Bi component, both the electrocatalytic and photoelectrocatalytic performance of the Pt-Bi aerogels can be manipulated. In this light, an impressive catalytic performance for electro-oxidation of methanol is acquired, marking a mass activity of 6.4-fold higher under UV irradiation than that for commercial Pt/C. This study not only sheds light on in situ manipulating NBBs of MAs, but also puts forward guidelines for crafting high-performance MAs-based electrocatalysts and photoelectrocatalysts toward energy-related electrochemical processes.

TcpC inhibits toll-like receptor signaling pathway by serving as an E3 ubiquitin ligase that promotes degradation of myeloid differentiation factor 88.

TcpC is a virulence factor of uropathogenic E. coli (UPEC). It was found that TIR domain of TcpC impedes TLR signaling by direct association with MyD88. It has been a long-standing question whether bacterial pathogens have evolved a mechanism to manipulate MyD88 degradation by ubiquitin-proteasome pathway. Here, we show that TcpC is a MyD88-targeted E3 ubiquitin ligase. Kidney macrophages from mice with pyelonephritis induced by TcpC-secreting UPEC showed significantly decreased MyD88 protein levels. Recombinant TcpC (rTcpC) dose-dependently inhibited protein but not mRNA levels of MyD88 in macrophages. Moreover, rTcpC significantly promoted MyD88 ubiquitination and accumulation in proteasomes in macrophages. Cys12 and Trp106 in TcpC are crucial amino acids in maintaining its E3 activity. Therefore, TcpC blocks TLR signaling pathway by degradation of MyD88 through ubiquitin-proteasome system. Our findings provide not only a novel biochemical mechanism underlying TcpC-medicated immune evasion, but also the first example that bacterial pathogens inhibit MyD88-mediated signaling pathway by virulence factors that function as E3 ubiquitin ligase.

Profiling transcriptional heterogeneity of epithelium, fibroblasts, and immune cells in esophageal squamous cell carcinoma by single-cell RNA sequencing.

Esophageal squamous cell carcinoma (ESCC) is one of the most aggressive malignancies with complex tumor microenvironment (TME) which has been proven to be associated with therapeutic failure or resistance. A deeper understanding of the complex TME and cellular heterogeneity is urgently needed in ESCC. Here, we generated single-cell RNA sequencing (scRNA-seq) of 25 796 immune and 8197 non-immune cells from three primary tumor and paired normal samples in ESCC patients. The results revealed intratumoral and intertumoral epithelium heterogeneity and tremendously differences in tumor and normal epithelium. The infiltration of myofibroblasts, one subtype of fibroblasts, might play important roles in the progression of ESCC. We also found that some differentially expressed genes and markers in epithelium and fibroblast subtypes showed prognostic values for ESCC. Diverse cell subtypes of T cells and myeloid cells were identified, including tumor-enriched HAVCR2+ CD4+ T cells with significantly exhausted signature. The epithelium and myeloid cells had more frequent cell-cell communication compared with epithelium and T cells. Taken together, this study provided in-depth insights into the cellular heterogeneity of TME in ESCC and highlighted potential therapeutic targets including for immunotherapy.

Spectrum and mortality of opportunistic infections among HIV/AIDS patients in southwestern China.

We describe the opportunistic infections (OIs) of HIV/AIDS to understand the spectrum, mortality, and frequency of multiple coinfected OIs among HIV/AIDS patients in southern China, where OIs are severe. We carried out a retrospective cohort study of hospitalized HIV-infected individuals at the Fourth People's Hospital of Nanning, Guangxi, China, from Jan. 2011 to May. 2019. The chi-square test was used to analyze cross-infection; the Kaplan‒Meier analysis was used to compare mortality. A total of 12,612 HIV-infected patients were admitted to this cohort study. Among them, 8982 (71.2%) developed one or more OIs. The overall in-hospital mortality rate was 9.0%. Among the patients, 35.6% coinfected one OI, and 64.4% coinfected more than two OIs simultaneously. Almost half of the patients (60.6%) had CD4 + T-cell counts < 200 cells/µL. Pneumonia (39.8%), tuberculosis (35.3%), and candidiasis (28.8%) were the most common OIs. Coinfected cryptococcal meningitis and dermatitis are the most common combined OIs. The rate of anaemia (17.0%) was highest among those common HIV-associated complications. Multiple OIs are commonly found in hospitalized HIV/AIDS patients in southwestern China, which highlights the need for improved diagnosis and treatment.

Cluster analysis of patients with chronic rhinosinusitis and asthma after endoscopic sinus surgery.

BACKGROUND: Patients with chronic rhinosinusitis with nasal polyps and asthma (CRSwAS) are highly heterogenous in severity and prognosis. The clinical phenotypes and inflammatory endotypes of CRSwAS and their association with outcomes of endoscopic sinus surgery (ESS) have not been fully studied yet. OBJECTIVE: We aimed to find out the clinical phenotypes of CRSwAS and explore their relationship with ESS outcomes using cluster analysis. METHODS: We recruited 103 consecutive adult patients with CRSwAS who had undergone ESS and been followed up for more than 1 year. For cluster analysis, we collected the data from 63 variables pertaining to demographic characteristics, preoperative disease status, surgical techniques, postoperative medical treatment, and outcomes. Eosinophilic CRS was defined as greater than or equal to 10 eosinophils/high-power field, and sinus computed tomography was evaluated by Lund-Mackay sinus computed tomography score (LM score). RESULTS: We screened 92 eligible patients and 13 preoperative variables for balanced iterative reducing and clustering using hierarchies cluster analysis. Patients with CRSwAS were divided into 4 clusters with distinct ESS outcomes: (1) cluster 1, characterized by aspirin-exacerbated respiratory disease, eosinophilic CRS, high preoperative LM score, moderate-to-severe asthma, and uncontrolled CRS after ESS; (2) cluster 2, characterized as having female dominance (66.67%), non-aspirin-exacerbated respiratory disease, eosinophilic CRS, high preoperative LM score, moderate-to-severe asthma, and uncontrolled CRS after ESS; (3) cluster 3, characterized as having female dominance (95.83%), noneosinophilic CRS, low preoperative LM score, moderate asthma, and controlled CRS after ESS; and (4) cluster 4, characterized as men-only, smoker, noneosinophilic CRS, low preoperative LM score, mild asthma, and controlled CRS after ESS. CONCLUSION: CRSwAS has distinct clusters, each corresponding to unique clinical and inflammatory characteristics and ESS outcomes.

CASA: a comprehensive database resource for the COVID-19 Alternative Splicing Atlas.

BACKGROUND: As a key process in transcriptional regulatory mechanisms, alternative splicing (AS) plays a crucial role in maintaining the diversity of RNA and protein expression, and mediates the immune response in infectious diseases, especially for the COVID-19. Therefore, urgent data gathering and more research of AS profiles in microbe-infected human cells are needed to improve understanding of COVID-19 and related infectious diseases. Herein, we have created CASA, the COVID-19 Alternative Splicing Atlas to provide a convenient computing platform for studies of AS in COVID-19 and COVID-19-related infectious diseases. METHODS: In CASA, we reanalyzed thousands of RNA-seq datasets generated from 65 different tissues, organoids and cell lines to systematically obtain quantitative data on AS events under different conditions. A total of 262,994 AS events from various infectious diseases with differing severity were detected and visualized in this database. In order to explore the potential function of dynamics AS events, we performed analysis of functional annotations and drug-target interactions affected by AS in each dataset. RNA-binding proteins (RBPs), which may regulate these dynamic AS events are also provided for users in this database. RESULTS: CASA displays microbe-induced alterations of the host cell splicing landscape across different virus families and helps users identify condition-specific splicing patterns, as well as their potential regulators. CASA may greatly facilitate the exploration of AS profiles and novel mechanisms of host cell splicing by viral manipulation. CASA is freely available at http://www.splicedb.net/casa/ .

Mitofusin 2 confers the suppression of microglial activation by cannabidiol: Insights from in vitro and in vivo models.

Currently, there is increasing attention on the regulatory effects of cannabidiol (CBD) on the inflammatory response and the immune system. However, the mechanisms have not yet been completely revealed. Mitofusin 2 (Mfn2) is a mitochondrial fusion protein involved in the inflammatory response. Here, we investigated whether Mfn2 confers the anti-inflammatory effects of CBD. We found that treatment with CBD decreased the levels of tumor necrosis factor α, interleukin 6, inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), and ionized calcium-binding adaptor molecule-1 (Iba1) in lipopolysaccharide (LPS)-challenged microglia. CBD also significantly suppressed the increase in reactive oxygen species (ROS) and the decline of mitochondrial membrane potential in BV-2 cells subjected to LPS. Interestingly, CBD treatment increased the expression of Mfn2, while knockdown of Mfn2 blocked the effect of CBD. By contrast, overexpression of Mfn2 reversed the increase in the levels of iNOS, COX-2, and Iba1 induced by Mfn2 small interfering RNA. In mice challenged with LPS, we found that CBD ameliorated the anxiety responses and cognitive deficits, increased the level of Mfn2, and decreased the expression of Iba1. Since neuro-inflammation and microglial activation are the common events that are observed in the experimental autoimmune encephalomyelitis (EAE) model of multiple sclerosis, we treated EAE mice with CBD. Mice that received CBD showed amelioration of clinical signs, reduced inflammatory response, and increased myelin basic protein level. Most importantly, the adeno-associated virus delivery of short hairpin RNA against Mfn2 reversed the protective effects of CBD. Altogether, these results indicate that Mfn2 is an essential immunomodulator conferring the anti-inflammatory effects of CBD. Our results also shed new light on the mechanisms underlying the protective effects of CBD against inflammatory diseases including multiple sclerosis.

Transition from stochastic events to deterministic ensemble average in electron transfer reactions revealed by single-molecule conductance measurement.

Electron transfer reactions can now be followed at the single-molecule level, but the connection between the microscopic and macroscopic data remains to be understood. By monitoring the conductance of a single molecule, we show that the individual electron transfer reaction events are stochastic and manifested as large conductance fluctuations. The fluctuation probability follows first-order kinetics with potential dependent rate constants described by the Butler-Volmer relation. Ensemble averaging of many individual reaction events leads to a deterministic dependence of the conductance on the external electrochemical potential that follows the Nernst equation. This study discloses a systematic transition from stochastic kinetics of individual reaction events to deterministic thermodynamics of ensemble averages and provides insights into electron transfer processes of small systems, consisting of a single molecule or a small number of molecules.

Cadmium chloride-induced apoptosis of HK-2 cells via interfering with mitochondrial respiratory chain.

Cadmium could induce cell apoptosis, probably related to the dysfunction of the mitochondrial respiratory chain. The human renal proximal tubule (HK-2) was used to explore the mechanism of mitochondrial respiratory chain dysfunction during apoptosis induced by cadmium chloride (CdCl2). Cell viability was evaluated by cell proliferation assay and different concentrations of 60, 80 and 100 µM were selected to evaluate the mitochondrial toxicity of CdCl2 respectively. Under the CdCl2 treatment for 24 h, the mitochondrial reactive oxygen species (ROS) of HK-2 cells increased and the superoxide dismutase (SOD) activity was inhibited at the above three concentrations separately. Both ATP content and mitochondrial membrane potential decreased significantly at 100 µM concentration. The levels of procaspase-3 and Bcl-2 had fallen in a concentration-dependent manner and Bax was significantly increased at 60, 80 and 100 µM concentration compared with no CdCl2 treatment respectively, which activated the mitochondrial apoptosis pathway. N-acetyl-cysteine (NAC) could partially resist CdCl2-induced cell apoptosis, while myxothiazol (Myx) promoted the process. Mitochondria relative alterations manifested as inhibition of complex III and V. In addition, both the quantity of mitochondrial coenzyme Q-binding protein CoQ10 homolog B (CoQ10B) and cytochrome c (Cyt c) had decreased significantly. Taken together, CdCl2 induced HK-2 apoptosis due to the mitochondrial respiratory chain dysfunction by reducing the CoQ10B level, offering a novel evaluating indicator for the environmental toxicity of CdCl2.

Author Correction: Gate controlling of quantum interference and direct observation of anti-resonances in single molecule charge transport.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Scalable production of intrinsic WX2(X = S, Se, Te) quantum sheets for efficient hydrogen evolution electrocatalysis.

Mass production of transition-metal dichalcogenides has attracted much attention to replace platinum-based catalysts for the hydrogen evolution reaction (HER). Herein, we demonstrate a general strategy for the scalable production of the intrinsic tungsten dichalcogenide (WX2(X = S, Se, Te)) quantum sheets (QSs) by an all-physical top-down method. The method combines silica-assisted ball-milling and sonication-assisted solvent exfoliation and thus enables production of WS2QSs, WSe2QSs, and WTe2QSs in exceedingly high yields of 28.2, 21.3, 19.9 wt%, respectively. The WX2QSs are confirmed as intrinsic and defect-free, which could be determinative to their improved HER performance. The overpotentials of 285, 331, 435 mV at the current density of 10 mA cm-2and Tafel slopes of 116, 78, 162 mV dec-1in acidic media, as well as charge transfer resistance values of 171, 242, 1973 Ω, are derived for WS2QSs, WSe2QSs, and WTe2QSs, respectively, which are much better than those of bulk materials. The WX2QSs exhibit high stability during the electrocatalysis as well. This work offers a powerful approach for fabrication of intrinsic QSs as efficient and robust electrocatalysts.

Simultaneous determination of capsid proteins in nine-valent human papilloma virus vaccines by liquid chromatography tandem mass spectrometry.

A liquid chromatography-tandem mass spectrometry method was developed to determine nine types of capsid proteins simultaneously in nine-valent human papillomavirus vaccines. Signature peptides were optimized in terms of specificity, repeatability, determination accuracy and sensitivity. As a result, three signature peptides per capsid protein were obtained. The linear calibration curves were achieved in the range of 11.6-373.6 nmol/L (R2  > 0.998). Compared to our previous liquid chromatography-tandem mass spectrometry method, the current method was more sensitive (3.18-fold) and it can be used for quality evaluation of nine-valent human papillomavirus vaccines, unlike the previous method, which could only be used for bivalent human papillomavirus vaccines. Then, they were utilized to determine nine types of capsid proteins in nine-valent human papillomavirus vaccines from four different manufactures. Intraday and interday precision values for the determination of capsid proteins in nine-valent human papillomavirus vaccines were less than 6.8 and 9.1%, respectively. Recovery rates of all capsid proteins investigated were in the range of 80-120%. In addition, the current assay was used for determination of free capsid protein in nine-valent human papilloma virus vaccines, and the results were used to evaluate the adsorption rate of the adjuvant.

Specific epigenetic microenvironment and the regulation of tumor-related gene expression by trichloroethylene in human hepatocytes.

Trichloroethylene (TCE), an important volatile organic solvent, causes a series of toxic damage to human. Conventional genetic mechanisms cannot fully explain its toxicity and carcinogenicity, indicative of the possible involvement of epigenetic mechanisms. Our study was intended to investigate the epigenetic toxicity and underlying mechanisms of TCE. Data showed that 0.3 mM TCE treatment for 24 h increased the growth of L-02 cells transiently. In contrast, subacute exposure to TCE inhibited cell growth and induced the genomic DNA hypomethylation and histone hyperacetylation. Further studies have revealed the TCE-induced DNA hypomethylation in the promoter regions of tumor-related genes, N-Ras, c-Jun, c-Myc, c-Fos and IGF-II, promoting their protein levels in a time-dependent manner. These results reveal there is a negative relationship existing between DNA hypomethylation and protein expression in tumor-related gene after TCE exposure under specific epigenetic microenvironment, serving as early biomarkers for TCE-associated diseases.