[Pollution Characteristics and Health Risk Assessment of Per- and Polyfluoroalkyl Substances and Emerging Alternatives in Road Dust, Shijiazhuang].

Per- and polyfluoroalkyl substances (PFASs, n=22), including emerging alternatives, in dust samples were analyzed using high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) to study their pollution characteristics. These samples were collected from main and minor roads in Shijiazhuang. Some of the roads were located near sewage treatment plants and fire stations. The results showed that PFASs were ubiquitous in the road dust of Shijiazhuang; in particular, hexafluoropropylene oxide dimer acid (HFPO-DA), an alternative, was measured for the first time in China. The total concentrations of PFASs ranged from 2.62 to 137.65 ng·g-1. Perfluorooctanoic acid (PFOA) was the dominant PFAS, followed by perfluorobutanoic acid (PFBA), HFPO-DA, and perfluorooctane sulfonic acid (PFOS). The highest and lowest levels of PFASs were observed in the northwest and southeast regions of Shijiazhuang, respectively. The compositions of PFASs were obviously different in road dust near sewage treatment plants and fire stations, especially for the types of emerging alternatives. Health risk assessment indicated that road dust intake had a low risk of human exposure to PFASs and emerging alternatives. Among the three routes (ingestion intake, inhalation intake, and dermal contact), ingestion intake was the main route for PFASs and emerging alternatives in road dust to enter the human body. Under the same exposure route, the exposure dose of children was higher than that of adults.

Methimazole and sodium perchlorate exert anti-thyroidal effects in the T3-induced Xenopus laevis metamorphosis assay: A rapid assay for screening thyroid disrupting chemicals.

Thyroid disrupting chemicals (TDCs) have received much attention due to their potential adverse effects on animal and human health, which calls for rapid screen assays to identify them. The triiodothyronine (T3)-induced Xenopus metamorphosis assay (TiXMA) we developed previously has been successfully applied to the detection of the TDCs disrupting thyroid hormone (TH) signaling. Here, we attempted to expand the application of the TiXMA to the screening of the TDCs interfering with the hypothalamic-pituitary-thyroid (HPT) axis. Two well-known TH synthesis inhibitors methimazole (MMI) and sodium perchlorate (SP) were employed to test the sensitivity of the TiXMA to the TDCs interfering with the HPT axis. As expected, we observed that the two chemicals concentration-dependently antagonized T3-induced morphological changes and body weight reduction of X. laevis tadpoles following 96 h-exposure, in parallel with blocked thyroid development and down-regulated tshß expression in the brain. All the data show that both MMI and SP exert inhibitory effects on T3-induced metamorphosis, indicating that the TiXMA is capable of screening the TDCs interfering with the HPT axis. In comparison with Amphibian Metamorphosis Assay (AMA), a 21-day assay for screening the TDCs interfering with the HPT axis, the TiXMA has a remarkable advantage of shorter exposure duration (96 h).

Receptor-Bound Perfluoroalkyl Carboxylic Acids Dictate Their Activity on Human and Mouse Peroxisome Proliferator-Activated Receptor γ.

In in vitro cell assays, nominal concentrations of a test chemical are most frequently used in the description of its dose-response curves. Although the biologically effective concentration (BEC) is considered as the most relevant dose metric, in practice, it is very difficult to measure. In this work, we attempted to determine the BEC of long-chain perfluoroalkyl carboxylic acids (PFCAs) in peroxisome proliferator-activated receptor γ (PPARγ) activity assays. In both adipogenesis and transcriptional activity assays with human and mouse cells, PPARγ activity of 7 PFCAs first increased and then decreased with their carbon chain length. The binding affinity of these PFCAs with the ligand-binding domain of PPARγ was measured by fluorescence competitive binding assay and showed very poor correlation with their receptor activity (r2 = 0.002-0.047). Internal concentrations of the PFCAs in the cells were measured by LC-MS/MS. Although their correlation with the receptor activity increased significantly, it is still low (r2 = 0.41-0.82). Using the binding affinity constant, internal concentration, and PPARγ concentration measured by immunoassays, concentrations of receptor-bound PFCAs in cells were calculated, which exhibited excellent correlation with PPARγ activity in both adipogenesis and transcriptional activity assays (r2 = 0.91-0.93). These results demonstrate that the concentration of receptor-bound PFCA is the BEC that dictates its activity on human and mouse PPARγ in cell assays. In the absence of any direct detection method, our approach can be used to calculate the target-site concentration of other ligands.

Elevated soluble ST2 concentration may involve in the progression of atrial fibrillation.

BACKGROUND: The aim of this study is to investigate the value of soluble suppression of tumorigenicity 2 (sST2) in Atrial fibrillation (AF) patients' risk prediction. METHODS: Healthy people (n = 60) and AF patients (n = 194) were consecutively enrolled into this project. RESULTS: In the health group, the mean age was 54 y (55% males). Serum median concentration of sST2 in healthy individuals was 17.04 ng/ml. In the AF patients group, the mean age was 61 years, and 64% were males. Median sST2 value was 21.69 ng/ml. According to subgroup analysis, median sST2 value of paroxysmal and persistent AF patients was 19.82 ng/ml and 24.15 ng/ml, respectively. Emergency AF patients showed much higher median sST2 concentration than AF outpatients (41.59 ng/ml vs. 20.53 ng/ml, p < 0.01). By multiple linear regression analysis adjusted for age and sex, heart failure (HF) and BNP strongly associated with sST2 concentration. After healthy people and AF patients with HF excluded, whether emergency visit or not become a patent predictor of sST2 concentration (n = 172). CONCLUSION: sST2 is probably an objective biomarker that can predict AF patients' risk of emergency admission or HF. Elevated sST2 concentration may involve in the progression of AF.

Population structure analysis of the neglected parasite Thelazia callipaeda revealed high genetic diversity in Eastern Asia isolates.

BACKGROUND: Thelazia callipaeda is the causative agent of thelaziasis in canids, felids and humans. However, the population genetic structure regarding this parasite remains unclear. METHODOLOGY/PRINCIPAL FINDINGS: In this study, we first explored the genetic variation of 32 T. callipaeda clinical isolates using the following multi-molecular markers: cox1, cytb, 12S rDNA, ITS1 and 18S rDNA. The isolates were collected from 13 patients from 11 geographical locations in China. Next, the population structure of T. callipaeda from Europe and other Asian countries was analyzed using the cox1 sequences collected during this study and from the GenBank database. In general, the Chinese clinical isolates of T. callipaeda expressed high genetic diversity. Based on the cox1 gene, a total of 21 haplotypes were identified. One only circulated in European countries (Hap1), while the other 20 haplotypes were dispersed in Korea, Japan and China. There were five nucleotide positions in the cox1 sequences that were confirmed as invariable among individuals from Europe and Asia, but the sequences were distinct between these two regions. Population differences between Europe and Asian countries were greater than those among China, Korea and Japan. The T. callipaeda populations from Europe and Asia should be divided into two separate sub-populations. These two groups started to diverge during the middle Pleistocene. Neutrality tests, mismatch distribution and Bayesian skyline plot (BSP) analysis all rejected possible population expansion of T. callipaeda. CONCLUSIONS: The Asian population of T. callipaeda has a high level of genetic diversity, but further studies should be performed to explore the biology, ecology and epidemiology of T. callipaeda.

Pb2+-Induced Allosteric PS2.M as A Label-Free Colorimetric Sensor for Detection of Cumulative Radon Radiation / 分析化学

A new sensitive method for detection of cumulative radon radiation based on the lead was established. PS2.M which stabilized by K+with hemin as a co-factor exhibits superior peroxidase-like activity, and can effectively catalyze the H2O2-mediated oxidation of TMB. In the presence of Pb2+, K+-stabilized PS2.M DNAzymes are induced to undergo a conformational change,because Pb2+has a higher efficiency with regard to stabilizing G-quadruplexes than K+, accompanied by a decrease of catalytic activity and a sharp decrease of readout signal. In the work, a novel"turn-off"model of colorimetry-Pb2+biosensor based on superior peroxidase-like activity of G-quadruplex for Pb2+analysis was developed. The fading degree of reaction system (△A value) was linearly related to Pb2+concentration in the range of 5. 0×10-9-1. 8× 10-7mol/L. The linear regression equation was △A=0.36+0.13C (10-8mol/L), with R=0.9987. The detection limits of lead and radon were 3.76 nmol/L(S/N=3) and 1.96×103Bq·h/m3(S/N=3), respectively. The method exhibited good selectivity, high sensitivity and convenient operation, and could avoid the radioactive hazard in determination of the radon in environment.

Comparative mitochondrial genomics among Spirometra (Cestoda: Diphyllobothriidae) and the molecular phylogeny of related tapeworms.

The larva of Spirometra erinaceieuropaei can parasitize humans, causing a serious parasitic zoonosis known as sparganosis. Although it is medically important, our knowledge about the phylogenetic position of S. erinaceieuropaei and its evolutionary history is fragmentary. In this study, complete mitochondrial (mt) genomes of 4 geographically distinct isolates of S. erinaceieuropaei spargana collected from 4 frog hosts (Hylarana guentheri, Rana nigromaculata, R. rugulosa, R. temporaria) were characterized using an Illumina sequencing platform. In addition, all available mt genomes of Cestoda in GenBank were included to reconstruct the phylogeny and to explore the evolutionary history of these tapeworms. The genome features of S. erinaceieuropaei contained 12 protein-coding genes (PCGs), 22 transfer RNA genes, 2 ribosomal RNA genes and 2 non-coding regions. Nucleotide sequences of mtDNA from different frog hosts were similar. Three genes, cox1, cytb and nad4, had high levels of nucleotide diversity. Phylogenetic analyses supported the sibling relationship between Bothriocephalidae and Diphyllobothriidae. Molecular dating analysis indicated that the divergence between Diphyllobothrium and Diplogonoporus started in the late Miocene. The mt genomes of S. erinaceieuropaei will serve as a useful dataset for studying the genetics and systematics of the species of Spirometra genus in particular and diphyllobothriid tapeworms in general.

New insights on serodiagnosis of trichinellosis during window period: early diagnostic antigens from Trichinella spiralis intestinal worms.

The clinical diagnosis of trichinellosis is difficult because its clinical manifestations are nonspecific. Detection of anti-Trichinella IgG by ELISA using T. spiralis muscle larval excretory-secretory (ES) antigens is the most commonly used serological method for diagnosis of trichinellosis, but the main disadvantage is false negativity during the early stage of infection. There is an obvious window period between Trichinella infection and antibody positivity.During the intestinal stage of Trichinella infection, the ES antigens of intestinal worms (intestinal infective larvae and adults) are exposed to host's immune system at the earliest time and elicit the production of specific anti-Trichinella antibodies. Anti-Trichinella IgG antibodies in infected mice were detectable by ELISA with ES antigens of intestinal worms as soon as 8-10 days post infection (dpi), but ELISA with muscle larval ES antigens did not permit detection of infected mice before 12 dpi. Therefore, the new early antigens from T. spiralis intestinal worms should be screened, identified and characterized for early serodiagnosis of trichinellosis.

Early detection of Trichinella spiralis DNA in the feces of experimentally infected mice by using PCR.

The aim of this study was to detect Trichinella spiralis DNA in mouse feces during the early stages of infection using PCR. The target gene fragment, a 1.6kb repetitive sequence of T. spiralis genome, was amplified by PCR from feces of mice infected with 100 or 300 larvae at 3-24h post infection (hpi) and 2-28dpi. The sensitivity of PCR was 0.016 larvae in feces. The primers used were highly specific for T. spiralis. No cross-reactivity was observed with the DNA of other intestinal helminths. T. spiralis DNA was detected in 100% (12/12) of feces of mice infected with 100 or 300 larvae as early as 3hpi, with the peak detection lasting to 12-24hpi, and then fluctuating before declining gradually. By 28dpi, the detection rate of T. spiralis DNA in feces of the two groups of infected mice decreased to 8.33% and 25%, respectively. PCR detection of T. spiralis DNA in feces is simple and specific; it might be useful for the early diagnosis of Trichinella infection.

Identification of protein tyrosine phosphatase SHP-2 as a new target of perfluoroalkyl acids in HepG2 cells.

Perfluoroalkyl acids (PFAAs) are widespread environmental contaminants which have been detected in humans and linked to adverse health effects. Previous toxicological studies mostly focused on nuclear receptor-mediated pathways and did not support the observed toxic effects. In this study, we aimed to investigate the molecular mechanisms of PFAA toxicities by identifying their biological targets in cells. Using a novel electrochemical biosensor, 16 PFAAs were evaluated for inhibition of protein tyrosine phosphatase SHP-2 activity. Their potency increased with PFAA chain length, with perfluorooctadecanoic acid (PFODA) showing the strongest inhibition. Three selected PFAAs, 25 µM perfluorooctanoic acid (PFOA), perfluorooctane sulfonic acid, and PFODA, also inhibited SHP-2 activity in HepG2 cells and increased paxillin phosphorylation level. PFOA was detected in the immunoprecipitated SHP-2 from the cells exposed to 250 µM PFOA, providing unequivocal evidence for the direct binding of PFOA with SHP-2 in the cell. Molecular docking rationalized the formation of PFAA/SHP-2 complex and chain length-dependent inhibition potency. Our results have established SHP-2 as a new cellular target of PFAAs.

The role of Somatic embryogenesis receptor-like kinase 1 in controlling pollen production of the Gossypium anther.

In flowering plants, male gametophytes are generated in anthers from microsporocytes. However, more evidence is needed to reveal the genetic mechanisms which regulate the differentiation and interaction of these highly specialized cells in anthers. Here we report the characterization of a series of male-sterile cotton (Gossypium hirsutum) mutants, including mutants with normal fertility, semi-sterility and complete sterility. These mutants are forms of transgenic cotton containing RNAi vectors with partial cDNA fragments of GhSERK1. The GhSERK1 gene encodes a putative leucine-rich repeat receptor protein kinase (LRR-RLK), and generally has 11 domains. In previous research, we found plants containing GhSERK1 produce an abundance of male reproductive tissue. In this paper, three RNAi constructs were designed separately to analyze its function in anther. After the three RNAi vectors were transformed into the cotton, transgenic plants with the specialized fragment exhibited normal fertility or the pollen energy decreased slightly, as ones with the homologous fragments exhibited various degrees of male sterility with different expression levels of GhSERK1 mRNA. In conclusion, for the transgenic plants with conserved fragments, lower expression levels of GhSERK1 mRNA were in transgenic plants, and a higher degree of male sterility was observed. Taking together, these findings demonstrate the GhSERK1 gene has a role in the development of anthers, especially in the formation of pollen grains. Also, we infer there must be another homolog of GhSERK1 in cotton, and both of GhSERK1 and its homolog function redundantly as important control points in controlling anther pollen production.

Effects of perfluorooctanesulfonate and perfluorobutanesulfonate on the growth and sexual development of Xenopus laevis.

Perfluorobutanesulfonate (PFBS), as a substitute for perfluorooctanesulfonate (PFOS), is widespread in the environment and biotic samples as well as PFOS. To investigate effects of PFOS and PFBS on the growth and sexual development of amphibians, we exposed Xenopus laevis tadpoles at a series of concentrations of PFOS and PFBS (0.1; 1; 100; 1,000 µg/l) as well as 17-beta-estradiol (E2, 100 ng/l) and 5 alpha-androstan-17-beta-ol-3-one (DHT, 100 ng/l) from stage 46/47 to 2 months postmetamorphosis. We found that neither PFOS nor PFBS had a significant effect on the survival and growth. However, they caused hepatohistological impairment at higher concentrations (100; 1,000 µg/l). Unlike E2, PFOS at all concentrations did not alter the sex ratio and induce intersex, but caused degeneration of spermatogonia in testes except for the lowest concentration. PFBS had no effect on the sex ratio and gonadal histology. PFOS and PFBS promoted expression of estrogen receptor (ER) and androgen receptor (AR), but not affected aromatase expression in the brain. The increase in expression of ER and AR suggests an increase in the responsiveness to the corresponding sex hormone and potential effects on sexual development. Our results show that PFBS as well as PFOS have adverse effects on hepato-histology and sexual development on X. laevis. Also, PFOS- and PFBS-induced increase in ER and AR expression highlights the need to further study effects of PFOS and PFBS on subsequently gonadal development, sexual dimorphism, and secondary sex characteristics in X. laevis. It is debatable that PFBS is widely used as a substitute of PFOS.

[Pollution levels of perfluorochemicals in chicken eggs and duck eggs from the markets in Beijing].

Pollution levels of perfluorochemicals in eggs purchased from the markets in Beijing had been investigated. The egg samples of chicken and duck were collected from the 59 stalls of 14 main eggs wholesale markets in Beijing, respectively. Systematic analyses were made for seventeen kinds of perfluorochemicals (11 perfluorinated carboxylates (PFCAs), 3 perfluorinated sulfonates (PFSAs), perfluorooctane sulfonamide (FOSA), 2-perfluorooctylethanoic acid (FOEA) and 2H-perfluoro-2-decenoic acid (FOUEA) by a high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). The results showed that there was a certain perfluorochemical contamination in all egg samples. Nine kinds of perfluorochemicals were detected in chicken eggs, perfluorononanoic acid (PFNA), perfluoroheptanoic acid (PFHpA) and perfluorooctanoate acid (PFOA) are dominant, and their average concentrations were 0.105, 0.073 and 0.069 ng x g(-1), respectively. Ten kinds of perfluorochemicals were detected in the duck eggs, perfluorooctane sulfonate (PFOS) and PFOA are dominant, and their average concentrations were 0.378 and 0.296 ng x g(-1), respectively. Perfluoropentanoic acid ( PFPeA), perfluorotetradecanoic acid (PFTA), perfluorobutane sulfonate (PFBS) and 2-perfluorooctylethanoic acid (FOEA) were not detected in all samples. The total concentration of PFCs in the duck eggs was 3.4 times of that in the chicken eggs. A strong positive correlation (r = 0.954) was not only observed between of PFNA and PFHpA in chicken eggs, but also found between perfluoroundecanoic acid (PFUnDA) and perfluorotridecanoic acid (PFTrDA) in duck eggs (r = 0.915). The results of health-based risk assessment showed that there was little immediate risk of exposure to PFOS and PFOA via the consumption of chicken eggs and duck eggs purchased from the markets in Beijing.

[Biological function of the Somatic embryogenesis receptor-like kinases in plant].

Somatic Embryogenesis Receptor-Like Kinases (SERKs) belong to the LRR-RLK II subfamily, which contain three conserved domains: an extracellular domain, a transmembrane domain, and an intracellular catalytic kinase domain. Previous studies had found that SERKs play many roles during plant development. This review made a brief introduction about the character of the SERKs and described the biological function of these proteins in somatic embryogenesis, sporogenesis, hormone response and host defense response. The research value and the application prospects of the SERKs were discussed.

A core-shell magnetic mesoporous silica sorbent for organic targets with high extraction performance and anti-interference ability.

C(18)-functionalized mesoporous silica shell was successfully fabricated on the surface of an Fe(3)O(4)/SiO(2) core to obtain an Fe(3)O(4)/SiO(2)/SiO(2)-C(18) magnetic microsphere. The microsphere exhibited high extraction efficiency to organic targets and strong anti-interference ability to natural organic matter. It could be easily isolated from water solution after extraction.

A new solid-phase extraction disk based on a sheet of single-walled carbon nanotubes.

A new kind of solid-phase extraction disk based on a sheet of single-walled carbon nanotubes (SWCNTs) is developed in this study. The properties of such disks are tested, and different disks showed satisfactory reproducibility. One liter of aqueous solution can pass through the disk within 10-100 min while still allowing good recoveries. Two disks (DD-disk) can be stacked to enrich phthalate esters, bisphenol A (BPA), 4-n-nonylphenol (4-NP), 4-tert-octylphenol (4-OP) and chlorophenols from various volumes of solution. The results show that SWCNT disks have high extraction ability for all analytes. The SWCNT disk can extract polar chlorophenols more efficiently than a C(18) disk from water solution. Unlike the activated carbon disk, analytes adsorbed by the new disks can be eluted completely with 8-15 mL of methanol or acetonitrile. Finally, the DD-disk system is used to pretreat 1000-mL real-world water samples spiked with BPA, 4-OP and 4-NP. Detection limits of 7, 25, and 38 ng L(-1) for BPA, 4-OP, and 4-NP, respectively, were achieved under optimized conditions. The advantages of this new disk include its strong adsorption ability, its high flow rate and its easy preparation.

[RelE toxin protein of Mycobacterium tuberculosis induces growth inhibition of lung cancer A-549 cell].

OBJECTIVE: To investigate whether the RelE toxin protein of mycobacterium tuberculosis has a growth inhibition effect on lung cancer A-549 cell. METHODS: The complete open-reading frame sequences of RelE, RelB and RelBE genes were amplified by PCR with using M. tuberculosis H37Rv genomic DNA as the template. The RelE, RelB and RelBE genes were subcloned into PcDNA3. 1 (+). After being verified with restriction endonuclease digestion and DNA sequence determination, the recombinant vectors were applied to transfect lung cancer A-549 cells by liposome transfection method. By determining the growth curve and protein level of living cells, MTT cell proliferation assay, the apoptosis of cells with HE staining and the apoptosis rate of transient transfection cells detected by Flow Microfluorimetry, it was observed and analyzed whether the RelE toxin protein of mycobacterium tuberculosis had a growth inhibition and apoptosis effects on lung cancer A-549 cell. RESULTS: The cell proliferation rate of lung cancer A-549 cells effected by the RelE toxin protein of mycobacterium tuberculosis was lower than that of the other groups, and this group cells with RelE protein effect showed more sensitive to nutrition starving. HE staining revealed that this group cells which included the transient transfection with RelE expression plasmid appeared to have more apoptosis cells and higher apoptotic rate than other groups did (P < 0.05). CONCLUSION: The RelE toxin protein of mycobacterium tuberculosis has growth inhibition and apoptotic effect on lung cancer A-549 cell.

Determination of sulfonamide compounds in sewage and river by mixed hemimicelles solid-phase extraction prior to liquid chromatography-spectrophotometry.

Mixed hemimicelles-based solid-phase extraction was investigated for the preconcentration of five sulfonamides from environmental water samples prior to HPLC-spectrophotometry determination in this paper. A comparative study on the use of sodium dodecyl sulfate (SDS) coating gamma-alumina or octadecyltrimethylammonium bromide (OTMABr) and OTMABr coating silica as sorbent materials were presented. The five analytes (sulfadiazine (SDA), sulfathiazole (STA), sulfapyridine (SPD), sulfamethazine (SMZ) and sulfamethoxazole (SMX)) were quantitatively adsorbed on OTMABr-gamma-alumina and OTMABr-silica mixed hemimicelles, but OTMABr-gamma-alumina was not adopted because it worked at a high pH (around 10), instead, OTMABr-silica was selected to overcoming the pH restriction. The analytes retained on the cartridge were quantitatively desorbed with suitable amounts of methanol. Factors influencing the extraction efficiency, such as the amount of surfactant, pH of sample and breakthrough volume were discussed. The proposed method had been applied to determining the five sulfonamides in several environmental water samples and concentration factors of 300 and 600 for SDA and other four analytes were achieved, respectively. Detection limits obtained ranged between 0.15 and 0.35microg/L for this five sulfonamides under the optimized conditions. The accuracy of the method was evaluated by recovery measurements on spiked samples, and good recovery results (89-113%) with precision of 3-6% were achieved.