Amorphous poly-N-vinylcarbazole polymer as a novel matrix for the determination of low molecular weight compounds by MALDI-TOF MS.

Traditional matrices for matrix-assisted laser desorption/ionization mass spectrometry (MALDI-TOF MS) are usually crystalline small molecules. The heterogeneous co-crystallization of the analyte and the matrix creates a sweet spot effect and reduces point-to-point reproducibility. In this study, an amorphous poly-N-vinylcarbazole polymer (PVK) was studied as a novel matrix for MALDI-TOF MS to detect various low molecular weight compounds (LMWCs) in the negative ion mode. The PVK achieved excellent matrix action and showed high sensitivity, good salt tolerance, and reproducibility. These results significantly broaden the design rules for new and efficient polymeric MALDI matrices.

Fabrication of Magnetic Al-Based Fe3O4@MIL-53 Metal Organic Framework for Capture of Multi-Pollutants Residue in Milk Followed by HPLC-UV.

The efficient capture of multi-pollutant residues in food is vital for food safety monitoring. In this study, in-situ-fabricated magnetic MIL-53(Al) metal organic frameworks (MOFs), with good magnetic responsiveness, were synthesized and applied for the magnetic solid-phase extraction (MSPE) of chloramphenicol, bisphenol A, estradiol, and diethylstilbestrol. Terephthalic acid (H2BDC) organic ligands were pre-coupled on the surface of amino-Fe3O4 composites (H2BDC@Fe3O4). Fe3O4@MIL-53(Al) MOF was fabricated by in-situ hydrothermal polymerization of H2BDC, Al (NO3)3, and H2BDC@Fe3O4. This approach highly increased the stability of the material. The magnetic Fe3O4@MIL-53(Al) MOF-based MSPE was combined with high-performance liquid chromatography-photo diode array detection, to establish a novel sensitive method for analyzing multi-pollutant residues in milk. This method showed good linear correlations, in the range of 0.05-5.00 µg/mL, with good reproducibility. The limit of detection was 0.004-0.108 µg/mL. The presented method was verified using a milk sample, spiked with four pollutants, which enabled high-throughput detection and the accuracies of 88.17-107.58% confirmed its applicability, in real sample analysis.

Development and perspectives of rapid detection technology in food and environment.

Food safety become a hot issue currently with globalization of food trade and food supply chains. Chemical pollution, microbial contamination and adulteration in food have attracted more attention worldwide. Contamination with antibiotics, estrogens and heavy metals in water environment and soil environment have also turn into an enormous threat to food safety. Traditional small-scale, long-term detection technologies have been unable to meet the current needs. In the monitoring process, rapid, convenient, accurate analysis and detection technologies have become the future development trend. We critically synthesizing the current knowledge of various rapid detection technology, and briefly touched upon the problem which still exist in research process. The review showed that the application of novel materials promotes the development of rapid detection technology, high-throughput and portability would be popular study directions in the future. Of course, the ultimate aim of the research is how to industrialization these technologies and apply to the market.

[Potential toxic effects of TDCIPP on the thyroid in female SD rats].

Objective: To investigate the potential toxic effects and mechanisms of Tris(1; 3-dichloro-2-propyl) phosphate (TDCIPP) on thyroid in female SD rats.Methods: Thirty-two 3-weeks-old female SD rats were randomly divided into normal group(treated with corn oil ), and low/moderate/high-dose group treated with TDCIPP (dissolved in corn oil )(n=8). All rats were treated with corn oil or TDCIPP (50, 100, 250 mg/(kg·d)) once a day during a 21-day period. All rats were sacrificed after the last administration. Serum thyroid stimulating hormone (TSH), 3,3',5-triiodothyronine (T3), 3,3',5,5'-tetraiodothyronine (T4), free 3,3',5,5'-tetraiodothyronine (FT4) were detected with ELISA kit. Morphology of thyroid was observed with hematoxylin and eosin (HE) staining. Expressions of genes and proteins correlate with thyroid were measured respectively by real-time fluorescence quantitative PCR and Western blot. Results: Compared with control group, morphology of thyroid showed follicles irregular arrangement, hypocolloid, and follicular hyperplasia in TDCIPP treatment groups. The levels of serum TSH in low-dose TDCIPP group and T3 in high-dose TDCIPP group were significantly higher than those in control group(P＜0.05). Thyroid stimulating hormone receptor (TSHR) mRNA expression was decreased distinctly in low-dose TDCIPP group, while the expression of thyroperoxidase (TPO) mRNA was increased notably in moderate and high-dose TDCIPP groups(P＜0.05,P＜0.01). Compared with control group, the level of TRß protein was decreased significantly in moderate and high-dose TDCIPP groups, while the expressions of udp-glucuronosyl-transferases (UGTs) and cytochrome-p450-3A1 (CYP3A1) proteins were upregulated notably in TDCIPP treatment groups(P＜0.05). Conclusion: Treated with 50 mg/(kg·d) TDCIPP can cause thyroid hyperplasia, change the levels of thyroid hormones, and disturb thyroid function, therefore, it has toxic effects on the thyroid.

The extracellular domain of Staphylococcus aureus LtaS binds insulin and induces insulin resistance during infection.

Insulin resistance is a risk factor for obesity and diabetes and predisposes individuals to Staphylococcus aureus colonization; however, the contribution of S. aureus to insulin resistance remains unclear. Here, we show that S. aureus infection causes impaired glucose tolerance via secretion of an insulin-binding protein extracellular domain of LtaS, eLtaS, which blocks insulin-mediated glucose uptake. Notably, eLtaS transgenic mice (eLtaS trans ) exhibited a metabolic syndrome similar to that observed in patients, including increased food and water consumption, impaired glucose tolerance and decreased hepatic glycogen synthesis. Furthermore, transgenic mice showed significant metabolic differences compared to their wild-type counterparts, particularly for the early insulin resistance marker α-hydroxybutyrate. We subsequently developed a full human monoclonal antibody against eLtaS that blocked the interaction between eLtaS and insulin, which effectively restored glucose tolerance in eLtaS trans and S. aureus-challenged mice. Thus, our results reveal a mechanism for S. aureus-induced insulin resistance.