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Preterm birth is an important issue of public reproductive health worldwide. The effects of the toxic metals on the likelihood of spontaneous preterm birth (SPB) are still under discussion. Our study aimed to investigate the association between maternal exposure to the five typical toxic metals or metalloid (i.e. arsenic (As), cadmium (Cd), chromium (Cr), mercury (Hg), and lead (Pb)) and the SPB likelihood. The mothers delivering fetus with SPB (cases) and those with term healthy birth (controls) were chosen from a prospective birth cohort of 3201 women carried out in Shanxi Province, China. A total of 147 SPB cases and 381 controls were included in our nested case-control study. We collected maternal general information by questionnaire and collected their blood sample during recruitment. The serum concentrations of the five toxic metals were measured by inductively coupled-plasma mass spectrometry. We found that the demographic information between the cases and controls were well balanced. The participants in our study had relatively higher serum As concentration. For the other toxic metals (i.e. Cd, Cr, Hg, and Pb), their serum concentrations were overall in the middle range of those from general population. There were no significant associations of the serum concentrations of the five concerned toxic metals with the SPB likelihood. Our study results overall did not support that maternal exposure to As or Cd significantly contribute to the SPB risk in the current exposure level, as well as the other three toxic metals. We further proposed their upper concentration limits in maternal serum from the perspective of SPB likelihood during the early pregnant period, i.e. 18.2 ng/mL of As, 1.05 ng/mL of Cd, 0.96 ng/mL of Cr, 1.07 ng/mL of Hg, and 1.54 ng/mL of Pb. Unlabelled Image • Maternal exposure to the toxic metals may increase the spontaneous preterm birth risk. • We recruited 147 SPB cases and 381 controls in our nested case-control study. • No significant associations of the serum toxic metals with the SPB risk were found. • Their upper limits in maternal serum from the perspective of SPB risk were proposed. [ABSTRACT FROM AUTHOR]

The degree of population exposure to various organic pollutants (OPs), including polycyclic aromatic hydrocarbons, organochlorinated pesticides, polychlorinated biphenyls, and polybrominated diphenyl ethers, can be determined by measuring their concentrations in human serum. However, performing large-scale measurements with such a variety of compounds in serum is challenging in terms of efficiency and cost. We describe herein the development of a high-efficiency extraction and sample cleanup protocol for simultaneous and quantitative analyses of OPs using gas chromatography-mass spectrometry. OPs, together with crude lipid impurities, were extracted from human serum with a mixture of n -hexane and methyl tert -butyl ether. A disperse sorbent composed of primary secondary amine and C18 (PSA/C18) was used to roughly remove co-extracted impurities. A combined column of neutral silica gel and neutral alumina oxide (AlO/SiG) was then used for deep cleanup. For the removal of impurities, the overall performance of our protocol for the analysis of OPs in serum was comparable to that of traditional gel permeation chromatography (GPC) and dramatically better than that of PSA/C18, which is a frequently used QuEChERS (quick, easy, cheap, effective, rugged, safe) based method. While both the proposed protocol and GPC yielded recoveries of 80%–110% for four classes of OPs, our protocol consumed about 10 times less solvent, resulting in lower experimental expenses and a lower risk of contamination from residual OPs in the solvent and other supplies. In contrast to GPC, our protocol also permits efficient batch processing of serum samples, allowing for large sample sizes such as those encountered in epidemiological studies. Image 1 • Simultaneous analysis of PAH, OCP, PCB, and PBDE in serum is of challenging. • We developed an efficient extraction and cleanup protocol for their serum analyses. • Our protocol yielded recoveries of 80%–110% with high lipid removal efficiency. • This protocol consumed almost 10 times less solvent than the traditional GPC method. • Dozens of minutes can be saved for each serum sample if samples are analyzed in batch. Our protocol permits efficient batch processing of serum samples for the simultaneous analysis of multi-class organic pollutants. [ABSTRACT FROM AUTHOR]

Vibrio parahaemolyticus is a seafood-borne Gram-negative bacteria causing diarrheal diseases in humans world wide. ToxR is a membrane-associated transcriptional factor which plays an important role in acid stress tolerance and regulates the expression of virulence genes including type III secretion system 1 (T3SS1) and type VI secretion system 1 (T6SS1) in V. parahaemolyticus. However, possible mechanisms of ToxR mediating virulence gene expression have not been fully understood. In this study, we demonstrated that ToxR is essential for V. parahaemolyticus to tolerate acid stress by constructing a ToxR deletion mutant (Δ toxR) and its complemented strain (toxR +). Quantitative PCR showed that the expression of toxR was up regulated under acid stress condition. RNA-seq analysis showed that ompU encoding one of outer membrane proteins was dramatically down regulated in Δ toxR. Furthermore, the mutation of ompU also led to a significant reduction in tolerating acid stress indicating that ToxR mediated acid stress through regulating ompU expression. RNA-seq results further confirmed that acid stress condition could alter multiple signaling pathways either depending on ToxR (e.g., quorum sensing, fatty acid metabolism) or independent of ToxR (e.g., biosynthesis of secondary metabolites, microbial metabolism in diverse environment, biosynthesis of antibiotics, biosynthesis of amino acids and carbon metabolism pathways). We also for the first time demonstrated that ToxR positively regulated the expression of T6SS2 gene and the interbacteria killing activity. Our study provides comprehensive understanding of signaling pathways which are regulated by both acid stress and ToxR. [ABSTRACT FROM AUTHOR]

Abstract In this paper, we focus on a food chain chemostat model with general response functions, perturbed by white noise. Under appropriate assumptions, we establish sufficient conditions for the existence of a unique ergodic stationary distribution by using stochastic Lyapunov analysis method. Our main effort is to construct the suitable Lyapunov function. [ABSTRACT FROM AUTHOR]

Bacterioferritin (Bfr) is a subfamily of ferritin protein family. Bfrs are composed of 24 identical subunits and self-assemble into 4‐3-2-fold symmetric cage-like structure with the incorporation of 12 heme groups into twelve 2-fold symmetric binding sites between subunits. Bfr protein cage has an outer diameter of ∼12 nm and interior cavity diameter of ∼8 nm with a total of 62 pores to connect the interior cavity with the bulk solution outside the protein nanocage. In vivo, the interior cavity of Bfr can store up to ∼2700 iron atoms in the ferrihydrite-like mineral. Recent years, more and more Bfr structures have been solved, which elucidated more details about the ferroxidase center, the catalytic mechanism, the possible channels used by iron ions to access the interior cavity, the electron transfer pathway involved in the iron redox cycle, and the molecular function of the heme group. The preliminary applications of both mammalian and bacterial ferritins in drug delivery, imaging diagnosis, and nanoparticle vaccine make Bfr exploration uniquely attractive for researchers from a broad range of research fields because Bfr has advantages over ferritins in controlling the self-assembly and redesigning the subunit. In this article, we outline the structure of Bfr, review the recent progress in the molecular mechanism of Bfr to store and release iron, and focus on the self-assembly and genetic modification of Bfr nanocage. Based on the comparison between Bfr and other ferritin family members, we further discuss the potential applications of Bfr. We expect that both fundamental and applied researches on Bfr will attract broad interest in protein nanocage design, nanomedicine, precise therapy, nanoparticle vaccine, bionanotechnology, bionanoelectronics, and so on. [ABSTRACT FROM AUTHOR]

In this paper, we consider a Lotka–Volterra food chain chemostat model that incorporates both distributed delay and stochastic perturbations. We obtain sufficient conditions for the existence of stationary distribution by constructing suitable Lyapunov functions. Stationary distribution indicates the two species in the chemostat can coexist in the long term. [ABSTRACT FROM AUTHOR]

Bioaccessibility is essential for evaluating dietary intake of contaminants. However, there is insufficient information on the dependence of dietary intake and risk assessment of dichlorodiphenyltrichloroethane and its metabolites (DDXs) and hexachlorocyclohexane isomers (HCHs) on bioaccessibility. Here, we investigated the bioaccessibilities of DDXs and HCHs in various foods and their influences on assessing exposure in the residents of Beijing City, China. Forty-three major foods in five types (fruit, vegetables, cereals, aquatic food, and meat) were sampled, and the bioaccessibility of DDXs and HCHs was evaluated using a static in vitro gastrointestinal digestion model. The bioaccessibility of DDXs in different food types ranked in the order of meat > vegetables > fruit > cereals > aquatic food, with mean ± standard deviation values of 62.2 ± 22.1%, 20.5 ± 10.6%, 12.4 ± 3.66%, 11.2 ± 9.69%, and 10.7 ± 4.97%, respectively. The highest average bioaccessibility of HCHs was found in meat (83.4 ± 14.2%), followed by fruit (41.0 ± 12.5%), vegetables (37.6 ± 18.1%), aquatic foods (24.2 ± 9.22%), and cereals (8.73 ± 4.07%). The estimated daily intakes (EDI) of the sum of DDXs and the sum of HCHs based on the bioaccessible concentration were only about 17% and 55% of the total EDI based on the residual concentration, respectively. Meat was found to play a more important role in EDI after bioaccessibility correction. The proportion of the population with potential non-carcinogenic and carcinogenic risks markedly decreased when considering bioaccessibility. It was concluded that bioaccessibility should be integrated into dietary exposure evaluation. [Display omitted] • The mean bioaccessibility (BA) of DDXs and HCHs varied in 43 foods in 1.55–93.4%. • Beijing residents still had a relatively high DDX and HCH intake level via foods. • Dietary exposure of DDXs and HCHs decreased 83% and 45% when BA was considered. • Residents still had potential exposure carcinogenic risks when BA was considered. MAIN FINDING OF THE WORK : We evaluated the bioaccessibility of DDXs and HCHs in various foods systematically and the dependence of dietary exposure evaluation on bioaccessibility. [ABSTRACT FROM AUTHOR]

• A new type of Dextran-polypyyrole nano-assemblies(Dex-PPy NAs) was synthetized. • This Dex-PPy NAs could be used as photothermal and photoacoustic imaging agent. • This Dex-PPy NAs shows great biocompatibility. Polypyrroles have shown great potential in photoacoustic imaging and photothermal therapy owing to its excellent photothermal conversion capabilities. However, the synthesis of polypyrrole-based nano-assemblies which have colloidal stability in biological buffers requires a number of steps, including the polymerization of pyrrole monomers, self-assembly of polypyrrole-based copolymers, and even an additional step to increase the biocompatibility of the nano-assemblies. Herein, a "polymerization/assembly" two-in-one synthesis is proposed for the first time to achieve the one-step synthesis of a new family of polypyrrole-based nano-assemblies, dextran-polypyrrole nano-assemblies (Dex-PPy NAs), under ambient conditions and in aqueous media. In addition, the approach employs tetravalent cerium ions as initiators which can initiate the polymerization of pyrrole monomers through the initiation of free radicals from dextran molecular chains. The resultant Dex-PPy NAs have a photothermal conversion efficiency reaching as high as 41 % and an excellent photostability. More importantly, the NAs with controllable nanoscale dimensions display no signs of cytotoxicity in both in vitro and in vivo studies owing to their biocompatible dextran "shell". An in vivo study further confirmed that the Dex-PPy NAs have excellent real-time photoacoustic imaging and photothermal therapy capabilities for malignant tumors. Therefore, this study represents an important step towards the scalable synthesis of polypyrrole-based nano-assemblies with photothermal/photoacoustic dual capabilities and enhanced biocompatibility. [ABSTRACT FROM AUTHOR]

Antimicrobial peptides (AMPs) are members of humoral immunity and particpate in resisting microbial invasion. In this study, an AMP gene hepcidin was obtained from the oriental loach Misgurnus anguillicaudatus and named Ma-Hep. This Ma-Hep encodes a peptide of 90 amino acids, with a predicted active peptide segment (Ma-sHep) of 25 amino acids at C terminus. Stimulation by a bacterial pathogen Aeromonas hydrophila resulted in significant up-regulation of Ma-Hep transcripts in loach midgut, head kidney, and gill. Ma-Hep and Ma-sHep proteins were expressed in Pichia pastoris and their antibacterial activity was examined. Results showed that Ma-sHep possessed stronger antibacterial activity against various Gram-positive and Gram-negative bacteria, compared to Ma-Hep. Scanning electron microscopy showed that Ma-sHep might kill bacteria by destroying bacterial cell membranes. Moreover, we found that Ma-sHep had an inhibitory effect on blood cell apoptosis induced by A. hydrophila and facilitated the bacterial phagocytosis and clearance in loach. Histopathological analysis indicated Ma-sHep could protect liver and gut of loach from bacterial infection. Ma-sHep has high thermal stability and PH stability, which is conducive to further feed addition. Feed supplemented with Ma-sHep expressing yeast improved the intestinal flora of loach by increasing the dominant bacteria and decreasing the harmful bacteria. Feed supplemented with Ma-sHep expressing yeast also regulated the expression of inflammatory related factors in various tissues of loach and reduced the mortality of loach upon bacterial infection. These findings show that the antibacterial peptide Ma-sHep is involved in the antibacterial defense of loach and can be used as a candidate for new antimicrobial agents in aquaculture. • The Hepcidin from Misgurnus anguillicaudatus was cloned and identified. • Ma-sHep possessed strong antibacterial activity against various bacteria. • Ma-sHep had an inhibitory effect on blood cell apoptosis induced by A. hydrophila. • Ma-sHep could protect loach tissues from bacterial infection. • Feed supplemented with Ma-sHep expressing yeast enhance immune capacity of loach. [ABSTRACT FROM AUTHOR]

The effects of ambient fine particulate matter (PM 2.5) exposure on blood pressure have been widely reported. However, there remains uncertainty regarding the underlying roles of particulate matter components. We aimed to investigate the association between ambient PM 2.5 exposure and blood pressure, as well as the potential effects of trace metal(loid)s, in a repeated-measurement study that enrolled women of childbearing age. Our study included 35 participants from Hebei Province, China, each of whom was visited for five times. During each visit, we conducted questionnaire surveys, measured blood pressure, and collected blood. The daily PM 2.5 exposure of participants was estimated according to their residential addresses using a spatiotemporal model that combined monitoring data with satellite measurements and chemical-transport model simulations. This model was used to calculate average PM 2.5 concentrations in 1, 3, 7, 15, 30, and 60 days prior to each visit. Serum concentrations of various trace metal(loid)s were measured. A linear mixed-effects model was used to investigate associations among study variables. Overall, the mean (standard deviation) 60 days PM 2.5 concentration over all five visits was 108.1(43.3) μg/m3. PM 2.5 concentration was positively associated with both systolic and diastolic blood pressures. Likewise, ambient PM 2.5 concentration was positively associated with serum concentrations of manganese and arsenic, and negatively associated with serum concentrations of nickel, tin, and chromium. Only the serum concentration of molybdenum was negatively associated with systolic blood pressure. We concluded that ambient PM 2.5 exposure may contribute to elevated blood pressure, potentially by interfering with internal intake of various metal(loid)s in the human body. Image 1 • We investigated the association between PM 2.5 exposure and blood pressure (BP). • A repeated measurement design was adopted for the 35 childbearing-age woman. • Their serum concentrations of various metal(loid)s were analyzed using ICP-MS. • Systolic and diastolic BPs were positively associated with PM 2.5 exposure. • PM 2.5 exposure may affect the serum metal(loid) levels of Mn, Ni, Sb, Cr and As. [ABSTRACT FROM AUTHOR]