Aspartate β-hydroxylase disrupts mitochondrial DNA stability and function in hepatocellular carcinoma

The mechanism of aberrant mitochondrial genome and function in hepatocellular carcinoma (HCC) remains largely unknown. Our previous study demonstrated an increased expression of aspartate β-hydroxylase (ASPH) in HCC tissues, which was associated with tumor invasiveness and a worse prognosis. Currently, we unexpectedly observed the presence of ASPH in purified mitochondrial protein fraction. In addition, immunostaining of both exogenously and endogenously expressed ASPH showed a colocalization with mitochondrial biomarkers. This study aimed to investigate whether the mitochondrial ASPH is involved in mitochondrial malfunction in HCC. Our results showed that ASPH overexpression in HCC tissues was correlated with decreased copy numbers of displacement loop (D-loop) and NADH dehydrogenase subunit 1 (ND-1) and enhanced D-loop mutation, suggesting the disrupted mitochondrial DNA (mtDNA) stability. The reduced mtDNA copy numbers were associated with aggressive clinicopathological features of HCC. The loss of mtDNA integrity induced by enforced expression of ASPH was accompanied with mitochondrial dysfunction, which was characterized by the aberrant mitochondrial membrane potential, decreased ATP generation and enhanced reactive oxygen species. In contrast, knocking down ASPH by siRNA in HCC cell lines showed the opposite impact on mtDNA integrity and function. Mass spectrometry and co-immunoprecipitation further identified that ASPH interacted with histone H2A member X (H2AX). ASPH overexpression diminished the interaction between H2AX and mitochondrial transcription factor A (mtTFA), an important DNA-binding protein for mtDNA replication, which then reduced the binding of mtTFA to D-loop region. Collectively, our results demonstrate that ASPH overexpression disrupts the mtDNA integrity through H2AX-mtTFA signal, thereby affecting mitochondrial functions in HCC.

Identification and measurement of staphylococcal enterotoxin M from Staphylococcus aureus isolate associated with staphylococcal food poisoning

Staphylococcus aureus produces a wide variety of staphylococcal enterotoxins (SEs, SEA to SEX), which are responsible for staphylococcal food poisoning. This study is aimed to establish a system to detect staphylococcal enterotoxin M (SEM) protein in food matrixes. In the present study, sem gene was characterized in a S. aureus isolate H4 associated with food poisoning. The amino acid sequence of the deduced SEM protein was same as that of previously identified SEM from S. aureus 04-02981. Subsequently, mature SEM protein was expressed in Escherichia coli BL21 (DE3) cells and purified with a Ni-NTA spin column. The polyclonal and monoclonal antibody against it were prepared. Using these antibodies, a highly sensitive, specific sandwich enzyme-linked immunosorbent assay (ELISA) system was developed capable of detecting SEM in milk, meat and rice. Cross-reactivity with SEB, SEI and SEK in this method was insignificant. Quantification of SEM secretion in vitro using this novel capture ELISA revealed that SEM was mainly secreted during the transition from the exponential to the stationary phase. Furthermore, sem gene and SEM protein production were screened by PCR and the developed ELISA system. The results indicated that there were two SEM+ strains of 19 S. aureus isolates originating in cold dishes and humans suffering from food poisoning. The investigations make it possible to assess SEM in food hygiene supervision in near future.

SIGNIFICANCE AND IMPACT OF THE STUDY

Staphylococcal enterotoxins (SE) are the main causative agents of staphylococcal food poisoning. Unlike classical SEs (SEA to SEE), the relationship between newly identified SEs (SEG to SEX) and staphylococcal food poisoning has not been clearly elucidated. Recently, mild emetic potential of staphylococcal enterotoxin M (SEM) has been demonstrated, which indicated that SEM might be associated with food poisoning. However, there is currently no commercial enzyme-linked immunosorbent assay (ELISA) kit available for immunological detection of it. Therefore, we developed a highly sensitive, specific sandwich ELISA system and assayed SEM in food matrixes. This assay facilitates the study of SEM expression in vitro and in vivo. In addition, the investigations would be helpful in addressing the relative incidence of SEM+ strains in near future.

Identification and measurement of staphylococcal enterotoxin-like protein I (SEll) secretion from Staphylococcus aureus clinical isolate

AIMS

Staphylococcus aureus (Staph. aureus) produces a wide variety of staphylococcal enterotoxins (SEs) and staphylococcal enterotoxin-like (SEl) proteins, which are the most causative agents of staphylococcal food poisoning. In contrast to classical SEs (SEA to SEE), the relationship between the novel SEs/SEls (SEG to SElX) and staphylococcal food poisoning is not elucidated. This study is aimed to establish a system to detect staphylococcal enterotoxin-like protein I (SElI) for analysis of staphylococcal food poisoning.

METHODS AND RESULTS

SElI was characterized in a Staph. aureus clinical isolate associated with food poisoning; there was an amino acid substitution Thr145Ala compared to previously identified SEI from Staph. aureus 04-02981. Subsequently, SElI was expressed, purified, and the poly- and monoclonal antibodies against it were prepared. Using these antibodies, a highly sensitive sandwich enzyme-linked immunosorbent assay (ELISA) that specifically detected and measured SElI secretion from the Staph. aureus clinical isolate in LB medium, milk and bloodstream was developed.

CONCLUSIONS

The ELISA system has been successfully applied for analysing SElI secretion in vivo and in vitro.

SIGNIFICANCE AND IMPACT OF THE STUDY

The highly sensitive ELISA should make it attractive for quantifying SElI in food hygiene supervision and clinical diagnosis in near future.

Potential role of biochars in decreasing soil acidification - A critical review

A large number of soils, worldwide, are acid (normally pH<5.5) and suffering from on-going soil acidification. Acid soils or soils undergoing acidification generally have low fertility and low crop productivity. Biochars have been reported to be of potential value in agriculture for improving soil properties and in reducing the hazards caused by soil acidification and in naturally acidic soils. However, the ameliorant effects of biochars on acid soils and the mechanisms involved have not previously been critically reviewed. Here we summarize the phenomena, and mechanisms involved in the improvement of soil acidity by biochars, the alleviation of aluminum toxicity, the enhancement of nutrient availability, and changes in nitrification by collating data in the literature. In addition, the agronomic effectiveness and environmental concerns in the incorporation of biochar and other soil additives (i.e. lime, industrial by-products, organic wastes and plant residues) to acid soils are systemically compared. We conclude that biochar is a potentially effective amendment to reverse or to prevent acidification in acid soils. Finally, perspectives for further research in terms of soil acidification are presented to address some issues that are still poorly understood and/or highly controversial.

Giant frequency down-conversion of the dancing acoustic bubble

We have demonstrated experimentally the existence of a giant frequency down-conversion of the translational oscillatory motion of individual submillimeter acoustic bubbles in water in the presence of a high frequency (500 kHz) ultrasonic standing wave. The frequency of the translational oscillations (~170 Hz) is more than three orders of magnitude smaller than that of the driving acoustic wave. We elucidate the mechanism of this very slow oscillation with an analytical model leading to an equation of translational motion of a bubble taking the form of Mathieu's equation. This equation illuminates the origin of the giant down conversion in frequency as arising from an unstable equilibrium. We also show that bubbles that form chains along the direction of the acoustic standing wave due to radiation interaction forces exhibit also translation oscillations that form a spectral band. This band extends approximately from 130 Hz up to nearly 370 Hz, a frequency range that is still at least three orders of magnitude lower than the frequency of the driving acoustic wave.

944 mJ Nd:YAG planar waveguide laser amplifier with the optical to optical efficiency of 52

We demonstrated a quasi-continuous wave (QCW) Nd:YAG planar waveguide laser amplifier with the single pulse output energy of 944 mJ. At the pulse repetition frequency (PRF) of 100 Hz, 1064 nm seed laser was coupled into the planar waveguide laser amplifier with the single pulse energy of 128 mJ and the pulse duration of 192 μs. With the total pump energy of 1582 mJ, the extracted energy of 816 mJ was obtained, leading to an optical to optical efficiency of 52% and an electrical to optical efficiency of 28%. To the best our knowledge, it is up to now the highest efficiency and output energy in Nd:YAG planar waveguide laser amplifier reported. At the maximum output, the beam quality factors M2 were measured to be 3.44 and 4.81 in the guided direction and unguided direction respectively, and the polarization degree was 98.6%. Higher average power could be obtained with the better performance of seeder oscillator.

The Prevalence, Clinical, and Molecular Characteristics of Congenital Hypothyroidism Caused by DUOX2 Mutations: A Population-Based Cohort Study in Guangzhou

Thyroid dyshormonogenesis (DH) has recently been reported to be more frequently associated with mutations in the dual oxidase 2 (DUOX2) gene. The present study was aimed to investigate the prevalence, clinical, and molecular characteristics of congenital hypothyroidism (CH) caused by DUOX2 mutations in Guangzhou. A population-based cohort of 156 patients with CH was recruited based on neonatal screening among 433 578 newborns born in Guangzhou from 2011 to 2012. Genetic analysis of DUOX2 was performed in 96 patients with suspected thyroid dyshormonogenesis (SDH) by PCR-amplified direct sequencing. Apart from 2 cases without ultrasonographic data, 118 (76.6%) of the 156 patients were classified as SDH and 36 (23.4%) as thyroid dysgenesis (TD) according to thyroid ultrasound at diagnosis. Genetic analysis revealed 23 different variants in 60 unrelated individuals (60/96, 62.5%), including 13 novel variants that were absent from HGMD, dbSNP databases, and the 50 normal controls. The novel missense variants were predicted to be pathogenic by SIFT and PolyPhen-2. The p.K530X was the most common mutation. Ninety-three percent of mutant alleles occurred in exons 5, 6, 9, 14, 17, 20, 25, 27, and 28. There were no significant differences in phenotypes between biallelic and monoallelic variants cases or between with-DUOX2 and non-DUOX2 variants cases. Most patients with DUOX2 defects (78.2%) were transient CH. In conclusion, the prevalence of DUOX2 pathogenic variants was high (62.5%) in this cohort. Thirteen novel probably pathologic variants were reported. The p.K530X was the most common mutation in the Chinese population. There was no correlation between DUOX2 genotypes and clinical phenotypes.

Lubricity of gold nanocrystals on graphene measured using quartz crystal microbalance

In order to test recently predicted ballistic nanofriction (ultra-low drag and enhanced lubricity) of gold nanocrystals on graphite at high surface speeds, we use the quartz microbalance technique to measure the impact of deposition of gold nanocrystals on graphene. We analyze our measurements of changes in frequency and dissipation induced by nanocrystals using a framework developed for friction of adatoms on various surfaces. We find the lubricity of gold nanocrystals on graphene to be even higher than that predicted for the ballistic nanofriction, confirming the enhanced lubricity predicted at high surface speeds. Our complementary molecular dynamics simulations indicate that such high lubricity is due to the interaction strength between gold nanocrystals and graphene being lower than previously assumed for gold nanocrystals and graphite.

Tristetraprolin: a novel mediator of the anticancer properties of resveratrol

Resveratrol is a natural compound that exhibits anticancer properties. Previous studies have proved that it can inhibit the proliferation of breast cancer cell lines and upregulate some cytokines such as cyclooxygenase-2 (COX-2) and vascular endothelial growth factor (VEGF). The initiation and progression of cancer are associated with the abnormal expression of multiple cytokines. Tristetraprolin (TTP), an mRNA-binding protein, is one of the key proteins that participate in regulating cytokine expression. Two different proliferation assays on MCF-7 cells showed that the cell proliferation rate significantly reduced following treatment with resveratrol. Most importantly, we found that resveratrol promoted TTP expression at both the mRNA and protein level in a dose- and time-dependent manner. In addition, the expression of COX-2 and VEGF were significantly suppressed by resveratrol while that of inducible nitric oxide synthase (iNOS) was upregulated. Lastly, the effects of resveratrol on both MCF-7 proliferation and expression of COX-2, VEGF, and iNOS were significantly inhibited by TTP knockdown, indicating that TTP mediates the anticancer properties of resveratrol. In summary, we conclude that resveratrol inhibits the proliferation of MCF-7 cells by TTP upregulation, which is associated with downregulation of COX-2 and VEGF and upregulation of iNOS.

Value of the Gastroesophageal Reflux Disease Questionnaire (GerdQ) in predicting the proton pump inhibitor response in coronary artery disease patients with gastroesophageal reflux-related chest pain

Chest pain experienced by patients with coronary artery disease can be partly due to gastroesophageal reflux-induced chest pain (GERP). Empirical proton pump inhibitor (PPI) therapy has been recommended as an initial clinical approach for treating GERP. However, PPI use may lead to some health problems. The Gastroesophageal Reflux Disease Questionnaire (GerdQ) may represent a noninvasive and cost-effective approach for avoiding PPI misuse and for identifying the appropriate patients for the PPI trial test. The aim of this pilot study was to prospectively evaluate the association between GerdQ scores and PPI response in patients with coronary artery disease (CAD) and GERP to determine whether the GerdQ predicts the PPI response in patients with CAD and GERP and to further validate the clinical application value of the GerdQ. A total of 154 consecutive patients with potential GERP were recruited to complete a GerdQ with subsequent PPI therapy. Based on the PPI trial result, patients were divided into a PPI-positive response group and a PPI-negative response group. The difference in the GerdQ scores between the two groups was assessed. The receiver operating characteristic (ROC) curve of GerdQ score was drawn according to the PPI response as the gold standard. The ability of GerdQ to predict the PPI response was assessed. A total of 96 patients completed the entire study; 62 patients (64.6%) were assigned to the PPI-positive response group, and 34 patients (35.4%) to the PPI-negative response group. The GerdQ score of the PPI-positive response group (8.11 ± 3.315) was significantly higher than that of the PPI-negative response group (4.41 ± 2.743), and the difference was statistically significant (t = 5.863, P = 0.000). The ROC curve was drawn according to a PPI response assessment result with a score above 2 as the gold standard. The area under curve was 0.806. When the critical value of GerdQ score was 7.5, Youden index was up to 0.514, the diagnostic sensitivity was 0.661, and the diagnostic specificity was 0.853. A GerdQ score greater than 7.5 better predicts the response to the PPI trial therapy. There is a strong association between the GerdQ score and the response to PPI therapy. Higher GerdQ scores were predictive of a positive PPI response in CAD patients with GERP. The GerdQ may be a reasonable screening tool for GERP in patients with CAD who are prepared to accept PPI therapy.

Interaction of an Ultrarelativistic Electron Bunch Train with a W-Band Accelerating Structure: High Power and High Gradient

Electron beam interaction with high frequency structures (beyond microwave regime) has a great impact on future high energy frontier machines. We report on the generation of multimegawatt pulsed rf power at 91 GHz in a planar metallic accelerating structure driven by an ultrarelativistic electron bunch train. This slow-wave wakefield device can also be used for high gradient acceleration of electrons with a stable rf phase and amplitude which are controlled by manipulation of the bunch train. To achieve precise control of the rf pulse properties, a two-beam wakefield interferometry method was developed in which the rf pulse, due to the interference of the wakefields from the two bunches, was measured as a function of bunch separation. Measurements of the energy change of a trailing electron bunch as a function of the bunch separation confirmed the interferometry method.

Association between genetic variants of EGF-containing fibulin-like extracellular matrix protein1 gene and sporadic breast cancer in a Chinese Han population

PURPOSE OF INVESTIGATION

Genetic susceptibility of breast cancer has been shown to be modulated by inheritance of polymorphic genes. EGF-containing fibulin-like extracellular matrix protein 1 (EFEMP1) gene played an important role in many tumors, including lung cancer, hepatic carcinoma, and prostate cancer. In addition, it was importantly downexpressed in breast cancer. The present research aimed to assess the association between genetic variations of EFEMP1 and breast cancer risk.

MATERIALS AND METHODS

The authors genotyped 11 common tagging SNPs with an array platform including 960 cases and 972 cancer-free controls of Chinese women, according to the HapMap database based on the pairwise linkage disequilibrium (LD) r² threshold of 0.8, minor allele frequency of 0.05.

RESULTS

Three SNPs were significant associated with breast cancer (rs3791679, p = 0.016, OR = 1.21, 95% CI = 1.04-1.41; rs1346786, p = 0.005, OR = 1.31, 95% CI = 1.08 -1.59; rs727878, p = 0.002, OR = 1.29, 95%CI = 1.10-1.51). Multivariate logistic regression analysis revealed that, compared with wild-type carriers in a dominant model, a significantly increased breast cancer risk was associated with the three identified risk SNPs. Among the selected tagging SNPs, three haplotype blocks were identified, and the results of haplotype analysis were consistent with the single-locus analysis. The haplotype 'GG' in block 1 and haplotype 'AG' in block 2 were significantly associated with breast cancer, and had a 54% and 28% increased breast cancer risk respectively, compared with their corresponding noncarriers.

CONCLUSIONS

The present results suggested that the polymorphisms of EFEMP1 gene were associated with breast cancer and might contribute to the susceptibility of the progression of breast cancer in Chinese Han women. Individuals with the risk alleles might increase the risk of breast cancer.