Discussion on the construction of food sampling team

Compared with the inspection， the sampling work directly faces the food producers and operators， which is more likely to be challenged and even raise objections in terms of standardization， representativeness， impartiality， randomness and timeliness. With the in-depth development of food safety sampling inspection， the requirements for the sampling team increased gradually. This paper discusses the construction of specialized and professional sampling team from the aspects of personnel， management， principle， reward and punishment in order to provide more ideas for relevant work. Through literature collection and comprehensive analysis， this paper combs the current situation and possible problems of China’s food safety sampling team， and proposes the targeted measures. Referring to the construction requirements of food inspection team， clarifying the qualification conditions， establishing the information base of sampling personnel， strengthening assessment and evaluation， and unifying supervision and management can effectively improve the professional skills， responsibility and professional pride of sampling team， and improve the quality and effectiveness of sampling work

Research progress on detection methods of N-dimethylnitrosamine in foods

N-dimethylnitrosamine is one of the most toxic nitrosamine compounds and can be produced in the process of food processing or storage. The detection methods are various with tedious operation and low accuracy. QuEChERS pretreatment combined with GC/LC-MS has been widely used in the determination of N-dimethylnitrosamine in food due to its advantages of simple operation， good extraction and purification， high sensitivity， stable recovery and effective improvement of detection rate and throughput. The pretreatment methods， detection equipment and detection parameters of N-dimethylnitrosamine in food were compared to analyze the advantages and disadvantages of different methods

Activation of the AMP-Activated Protein Kinase by Eicosapentaenoic Acid (EPA, 20:5 n-3) Improves Endothelial Function In Vivo

The aim of the present study was to test the hypothesis that the cardiovascular-protective effects of eicosapentaenoic acid (EPA) may be due, in part, to its ability to stimulate the AMP-activated protein kinase (AMPK)-induced endothelial nitric oxide synthase (eNOS) activation. The role of AMPK in EPA-induced eNOS phosphorylation was investigated in bovine aortic endothelial cells (BAEC), in mice deficient of either AMPKα1 or AMPKα2, in eNOS knockout (KO) mice, or in Apo-E/AMPKα1 dual KO mice. EPA-treatment of BAEC increased both AMPK-Thr172 phosphorylation and AMPK activity, which was accompanied by increased eNOS phosphorylation, NO release, and upregulation of mitochondrial uncoupling protein-2 (UCP-2). Pharmacologic or genetic inhibition of AMPK abolished EPA-enhanced NO release and eNOS phosphorylation in HUVEC. This effect of EPA was absent in the aortas isolated from either eNOS KO mice or AMPKα1 KO mice fed a high-fat, high-cholesterol (HFHC) diet. EPA via upregulation of UCP-2 activates AMPKα1 resulting in increased eNOS phosphorylation and consequent improvement of endothelial function in vivo

Tyrosine Nitration of PA700 Links Proteasome Activation to Endothelial Dysfunction in Mouse Models with Cardiovascular Risk Factors

Oxidative stress is believed to cause endothelial dysfunction, an early event and a hallmark in cardiovascular diseases (CVD) including hypertension, diabetes, and dyslipidemia. However, the targets for oxidative stress-mediated endothelial dysfunction in CVD have not been completely elucidated. Here we report that 26S proteasome activation by peroxynitrite (ONOO−) is a common pathway for endothelial dysfunction in mouse models of diabetes, hypertension, and dyslipidemia. Endothelial function, assayed by acetylcholine-induced vasorelaxation, was impaired in parallel with significantly increased 26S proteasome activity in aortic homogenates from streptozotocin (STZ)-induced type I diabetic mice, angiotensin-infused hypertensive mice, and high fat-diets -fed LDL receptor knockout (LDLr−/−) mice. The elevated 26S proteasome activities were accompanied by ONOO−-mediated PA700/S10B nitration and increased 26S proteasome assembly and caused accelerated degradation of molecules (such as GTPCH I and thioredoxin) essential to endothelial homeostasis. Pharmacological (administration of MG132) or genetic inhibition (siRNA knockdown of PA700/S10B) of the 26S proteasome blocked the degradation of the vascular protective molecules and ablated endothelial dysfunction induced by diabetes, hypertension, and western diet feeding. Taken together, these results suggest that 26S proteasome activation by ONOO−-induced PA700/S10B tyrosine nitration is a common route for endothelial dysfunction seen in mouse models of hypertension, diabetes, and dyslipidemia

Finishing the euchromatic sequence of the human genome

The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead

Regulation of the proteasome by AMPK in endothelial cells: the role of O-GlcNAc transferase (OGT).

26S proteasome is a macromolecular multi-subunit complex responsible for recognizing, unfolding, and ultimately destroying proteins. It remains poorly understood how 26S proteasome activity is regulated. The present study was to investigate if AMP-activated protein kinase (AMPK) functions as a physiological suppressor of the 26S proteasome in endothelial cells. 26S proteasome assembly, activity, and O-GlcNAcylation of P700 were assayed in cultured human umbilical vein endothelial cells (HUVEC) and mouse aortas isolated from C57BL6 wild type and AMPKα2 knockout mice with or without being exposed to selective AMPK activators or inhibitors. Pharmacological and genetic activation of AMPK effectively suppresses 26S proteasomes in endothelial cells. Conversely, inactivation of AMPK either pharmacologically or genetically increases 26S proteasome activity; furthermore, the inactivation decreases the O-GlcNAcylation of PA700/S10B (the regulatory complex in 26S proteasomes) and increases the assembly of 26S proteasomes. In contrast, AMPK activation increases levels of O-GlcNAcylated PA700/S10B, likely through enhanced association of PA700 with O-GlcNAc transferase (OGT), the enzyme that catalyzes protein O-GlcNAcylation. Finally, aortas from AMPK-KO vs wild type mice exhibit elevated 26S proteasome activity in parallel with decreased PA700/S10B O-GlcNAcylation and PA700/S10B-OGT association. Taken together, we conclude that AMPK functions as a physiological suppressor of 26S proteasomes

Increased 26S proteasome activity in AMPK-suppressed HUVEC is correlated with the enhanced association of 19S and 20S sub-complexes.

<p>Compound C (10 µmol/L for 2 hour)-treated HUVEC present (A) AMPK inactivation, (B) an increase in association of PA700/S10B (from 19S complex) with β7 (from 20S complex), which can be blocked by AICAR pre-incubation (2 mmol/L for 6 hours), (C) 26S proteasome assembly (same samples were run on 3–14% native-PAGE under non-reducing condition followed by conventional Western blot on duplicated blots with PA700/S10B and β7 antibodies, respectively), and (D) an increase in 26S proteasome activity (chymotrypsin-like) (n = 3). The increased association of proteasome sub-complex is also observed in (E) HUVEC overexpressing AMPK-DN but not AMPK-CA or GFP. All of the blots shown are representative of 3 independent experiments. NS represents not significant.</p

AMPK depletion is associated with decreased association of OGT with proteasome and increased 26S proteasome assembly and activity in AMPK-KO mice.

<p>Gender (male) and age (12 weeks) matched mice (n = 8/group) with the genotypes of wild type (C57BL/6J) and AMPKα knockout were used. Compared to aortas from wild type (C57BL/6J) mice, (A) aortas from AMPKα knockout mice exhibit (B) a decrease in the association of OGT with proteasome (PA700/S10B), (C) an increase in proteasome assembly (PA700/S10B-β7 association), and (D) an increase in 26S proteasome activity, without alteration in the expression levels of proteasome (β7 or PA700/S10B) or OGT. * represents p<0.05 vs wild type (n = 8).</p

Activation of OGT prevents AMPK-inhibition induced 26S proteasome activation.

<p>AMPK suppression by compound C (10 µmol/L for 2 hour) in HUVEC (A) increases the association of PA700/S10B (from 19S complex) with β7 (from 20S complex) accompanied by a decrease of PA700/S10B O-GlcNAc modification, and (B) increases 26S proteasome activity, which can be prevented by pre-incubation of UDP-GlcNAc (25 µmol/L for 30 min), but not by PUGNAc (14 µmol/L for 30 min), the inhibitor of O-GlcNAcase. The blots shown are representative of 3 independent experiments.</p