Screening of 439 Pesticide Residues in Fruits and Vegetables by Gas Chromatography-Quadrupole-Time-of-Flight Mass Spectrometry Based on TOF Accurate Mass Database and Q-TOF Spectrum Library.

Because of its unique characteristics of accurate mass full-spectrum acquisition, high resolution, and fast acquisition rates, GC-quadrupole-time-of-flight MS (GC-Q-TOF/MS) has become a powerful tool for pesticide residue analysis. In this study, a TOF accurate mass database and Q-TOF spectrum library of 439 pesticides were established, and the parameters of the TOF database were optimized. Through solid-phase extraction (SPE), whereby pesticides are extracted from fruit and vegetable substrates by using 40 mL 1% acetic acid in acetonitrile (v/v), purified by the Carbon/NH2 SPE cartridge, and finally detected by GC-Q-TOF/MS, the rapid analysis of 439 pesticides in fruits and vegetables can be achieved. The methodology verification results show that more than 70 and 91% of pesticides, spiked in fruits and vegetables with concentrations of 10 and 100 µg/kg, respectively, saw recoveries that conform to the European Commission's criterion of between 70 and 120% with RSD ≤20%. Eighty-one percent of pesticides have screening detection limits lower than 10 µg/kg, which makes this a reliable analysis technology for the monitoring of pesticide residues in fruits and vegetables. This technology was further validated for its characteristics of high precision, high speed, and high throughput through successful detection of 9817 samples during 2013-2015.

Angiotensin II type 1 receptor autoantibodies induces INS-1 islet β-cell apoptosis by upregulation of autophagy / 中国病理生理杂志

AIM:To explore whether the angiotensin II type 1 receptor autoantibodies(AT1-AA)induces islet β-cell apoptosis and whether autophagy is involved in the process.METHODS:The INS-1 cells treated with AT1-AA at 10-6mol/L for 24 h,and then the apoptosis was analyzed by flow cytometry,Western blot and Hoechst 33258 staining.In addition,the expression of autophagy-related proteins such as LC3 and beclin 1 were determined by Western blot.The effects of AT1-AA on the apoptosis,autophagy and viability of INS-1 cells with or without 3-methyladenine(3-MA;a com-mon autophagy inhibitor)or telmisartan(an angiotensin Ⅱ type 1 receptor blocker)pretreatment, were detected by flow cytometry,Western blot and CCK-8 assay.RESULTS: Treatment with AT1-AA at 10 -6mol/L for 24 h significantly re-duced the cell viability(P<0.05).Compared with the negative IgG control group,the apoptotic cells increased after incu-bation with AT1-AA for 12 h,24 h and 36 h,respectively(P<0.05).Moreover,the protein levels of LC3 and beclin 1 also increased gradually with the prolongation of treatment time,and the elevation of apoptosis and autophagy were blocked by telmisartan.After pretreatment with 3-MA, the apoptotic rate of the cells was obviously decreased compared with the cells treated with AT1-AA alone.CONCLUSION: AT1-AA induces the apoptosis of INS-1 islet βcells by upregulating autophagy via the angiotensin Ⅱtype 1 receptor pathway.

Activation of caspase-12 at early stage contributes to cardiomyocyte apoptosis in trauma-induced secondary cardiac injury / 生理学报

Trauma-induced secondary cardiac injury (TISCI) is associated with increased adverse cardiac events and death. We have previously reported that TISCI results in myocardial apoptosis and secondary cardiac dysfunction. However, the underlying mechanism is unclear. To identify the time course of trauma-induced cardiomyocyte apoptosis and possible apoptotic pathway, traumatic rat models were built with Noble-Collip drum. Meanwhile, normal rat cardiomyocytes were cultured with traumatic plasma (TP) for 48 h. Cardiomyocyte apoptosis, cardiac function and the apoptosis related enzymes, including caspase-3, -8, -9, and -12, were determined. The results showed that there was no direct injury of rat hearts immediately after trauma. However, compared with hearts from the sham rats, hearts isolated from traumatic rats exhibited reduced +dP/dTand -dP/dT24 h after trauma. In traumatic rats, myocardial apoptotic index and caspase-3 activity obviously increased 6 h after trauma, and achieved the maximal value 12 h after trauma. The activity and expression of caspase-12, an endoplasmic reticulum (ER) stress-specific caspase, elevated markedly 3 h after trauma and reached its peak 6 h after trauma. Otherwise, caspase-8 (extrinsic apoptotic pathway) and caspase-9 (intrinsic apoptotic pathway) in the myocardial tissue of traumatic rats were activated 24 h after trauma. Meanwhile, incubation of normal rat cardiomyocytes with TP increased caspase-12 activity at 6 h, caspase-3 activity at 12 h, caspase-8 and -9 activities at 24 h, respectively. TP-induced cardiomyocyte apoptosis was virtually abolished by Z-ATAD-FMK (a caspase-12 specific inhibitor). In addition, there was a significant negative correlation between myocardial caspase-12 activity and trauma-induced secondary cardiac dysfunction. Our present study demonstrated that caspase-12 is firstly activated and plays an important role in TISCI rats. Inhibition of caspase-12 mediated apoptosis may be a novel strategy in ameliorating posttraumatic cardiomyocyte apoptosis and secondary cardiac injury.

[Application of ICP-MS method in the determination of mineral elements in vitex honey for the classification of their geographical origins with chemometric approach].

In the present work, the contents of 38 elements of 65 vitex (Vitex negundo var. heterophylla Rehd. ) honey samples from Shunyi of Beijing, Fuping and Pingshan of Hebei province were determined by inductively coupled plasma mass spectrometry (ICP-MS). Among them, B, Na, Mg, P, K, Ca, Fe and Zn were the most abundant elements with mean contents more than 1 mg kg-1. It can be found that there were relationships between the contents of elements and the geographical origin of vitex honey samples. Taking the contents of 29 out of 38 mineral elements (Na, Mg, Al, K, Ti, V, Mn, Fe, Ni, Cu, Zn, Ga, As, Sr, Y, Mo, Cd, Ba, La, Ce, Pr, Nd, Sm, Gd, Dy, Ho, T1, Pb and U) as variables, the chemometric methods, such as principal component analysis (PCA) and back-propagation artificial neural network (BP-ANN), were applied to classify vitex honey samples according to their geographical origins. PCA reduced all of the variables to four principal components and could explain 81. 6% of the total variances. The results indicated that PCA could mainly classify the vitex honey samples into three groups. BP-ANN was explored to construct classification model of vitex honeys according to their geographical origin. For the whole data set, the overall correct classification rate and cross-validation (leave one out method) rate of proposed BP-ANN model was 100% and 95. 4%, respectively. To further test the stability of the model developed for prediction, 75% of honey samples of each geographical origin were randomly selected for the model training set, and the remaining samples were classified with the use of the constructed model. Both the overall correct classification rate and prediction rate of proposed BP-ANN model were 100%. It is concluded that the profiles of multi-element by ICP-MS with chemometric methods could be a potential and powerful tool for the classification of vitex honey samples from different geographical origins.