Yuanyuan Zhang

The SiO2 shell was coated on Fe3O4 nanoparticle by hydrolyzation of Na2SiO3, and then thiol groups were modified on the Fe3O4@SiO2 through silanization reaction to form Fe3O4@SiO2–SH sorbents. Characterization with transmission electron microscope (TEM), Energy-dispersive spectroscope (EDS), and X-ray photoelectron spectroscopy (XPS) proved that SiO2 and thiol groups were successfully covered on the surface of Fe3O4 nanoparticle. The Fe3O4 core possessed superparamagnetism for magnetic separation, and the SiO2 shell could protect the Fe3O4 core from being oxidized or dissolved under acid solution and provide good modificability. Due to the strong interaction between mercury and thiol groups, the synthesized sorbents exhibited high adsorption capacity and good anti-interference ability during mercury adsorption. The maximum adsorption capacity calculated from Langmuir fitting was 148.8 mg/g at pH 6.5, and the sorbents still maintained good adsorption ability at low solution pH and high concentration of coexisting cations. Mercury loaded on the sorbents could be easily desorbed with 1 mol/L HCl containing 3 wt.% of thiourea, and the sorbents showed good reusability. The adsorption capacities were still kept over 110 mg/g in tested natural water samples, showing practical significance in remediation of mercury contaminated actual water.

The present study was conducted to investigate the effects of maternal zearalenone (ZEN) exposure on the intestine of pregnant Sprague-Dawley (SD) rats and its offspring. Ninety-six pregnant SD rats were randomly divided into four groups and were fed with diets containing ZEN at concentrations of 0.3 mg/kg, 48.5 mg/kg, 97.6 mg/kg or 146.0 mg/kg from gestation days (GD) 1 to 7. All rats were fed with mycotoxin-free diet until their offspring were weaned at three weeks of age. The small intestinal fragments from pregnant rats at GD8, weaned dams and pups were collected and studied for toxic effects of ZEN on antioxidant status, immune response, expression of junction proteins, and morphology. The results showed that ZEN induced oxidative stress, affected the villous structure and reduced the expression of junction proteins claudin-4, occludin and connexin43 (Cx43) in a dose-dependent manner in pregnant rats. Different effects on the expression of cytokines were also observed both in mRNA and protein levels in these pregnant groups. Ingestion of high levels of ZEN caused irreversible damage in weaned dams, such as oxidative stress, decreased villi hight and low expression of junction proteins and cytokines. Decreased expression of jejunal interleukin-8 (IL-8) and increased expression of gastrointestinal glutathione peroxidase (GPx2) mRNA were detected in weaned offspring, indicating long-term damage caused by maternal ZEN. We also found that the Nrf2 expression both in mRNA and protein levels were up-regulated in the ZEN-treated groups of pregnant dams and the high-dose of ZEN group of weaned dams. The data indicate that modulation of Nrf2-mediated pathway is one of mechanism via which ZEN affects gut wall antioxidant and inflammatory responses.

Lipocalin 2 (Lcn2) has been recently characterized as a new adipokine having a role in innate immunity and energy metabolism. Nonetheless, the metabolic regulation of Lcn2 production in adipocytes has not been comprehensively studied. To better understand the Lcn2 biology, we investigated the regulation of Lcn2 expression in adipose tissue in response to metabolic stress in mice as well as the control of Lcn2 expression and secretion by cytokines and nutrients in 3T3-L1 adipocytes. Our results showed that the mRNA expression of Lcn2 was upregulated in white and brown adipose tissues as well as liver during fasting and cold stress in mice. Among pro-inflammatory cytokines TNFα, IL-1β, and IL-6, IL-1β showed most profound effect on Lcn2 expression and secretion in 3T3-L1 adipocytes. Insulin stimulated Lcn2 expression and secretion in a dose-dependent manner; this insulin effect was significantly abolished in the presence of low concentration of glucose. Moreover, insulin-stimulated Lcn2 expression and secretion was also attenuated when glucose was replaced by 3-O-methyl-d-glucose or by blocking NFκB pathway activation. Additionally, we showed that palmitate and oleate induced Lcn2 expression and secretion more significantly than EPA, while phytanic acid reduced Lcn2 production. Our results demonstrated that Lcn2 production in adipocytes is highly responsive to metabolic stress, cytokines, and nutrient signals, suggesting an important role of Lcn2 in adipocyte metabolism and inflammation.