The Regulatory Role of MeAIB in Protein Metabolism and the mTOR Signaling Pathway in Porcine Enterocytes.

Amino acid transporters play an important role in cell growth and metabolism. MeAIB, a transporter-selective substrate, often represses the adaptive regulation of sodium-coupled neutral amino acid transporter 2 (SNAT2), which may act as a receptor and regulate cellular amino acid contents, therefore modulating cellular downstream signaling. The aim of this study was to investigate the effects of MeAIB to SNAT2 on cell proliferation, protein turnover, and the mammalian target of rapamycin (mTOR) signaling pathway in porcine enterocytes. Intestinal porcine epithelial cells (IPEC)-J2 cells were cultured in a high-glucose Dulbecco's modified Eagle's (DMEM-H) medium with 0 or 5 mmoL/L System A amino acid analogue (MeAIB) for 48 h. Cells were collected for analysis of proliferation, cell cycle, protein synthesis and degradation, intracellular free amino acids, and the expression of key genes involved in the mTOR signaling pathway. The results showed that SNAT2 inhibition by MeAIB depleted intracellular concentrations of not only SNAT2 amino acid substrates but also of indispensable amino acids (methionine and leucine), and suppressed cell proliferation and impaired protein synthesis. MeAIB inhibited mTOR phosphorylation, which might be involved in three translation regulators, EIF4EBP1, IGFBP3, and DDIT4 from PCR array analysis of the 84 genes related to the mTOR signaling pathway. These results suggest that SNAT2 inhibition treated with MeAIB plays an important role in regulating protein synthesis and mTOR signaling, and provide some information to further clarify its roles in the absorption of amino acids and signal transduction in the porcine small intestine

Developing High-Energy Dissipative Soliton 2 μm Tm3+-Doped Fiber Lasers

In recent years, mid-infrared (mid-IR) lasers have attracted a great interest over the world. During the development of mid-IR laser sources, the 2 μm Tm3+-doped fiber laser (TDFL) has played an important role for its specific emission wavelength between near-IR and mid-IR. Its great potential applications include sensing, medical surgery, ranging, telecommunications, and pump sources for developing 3–5 μm laser systems. Though the continuous-wave (CW) output power of 2 μm TDFLs has been scaled to over 1000 W, high-pulse-energy ultrafast 2 μm TDFLs are still limited by nonlinear optical effects. In traditional soliton mode-locking, the pulse energy has an upper limit defined by the soliton area theorem (or energy quantization principle). For improving the pulse energy of 2 μm fiber lasers, dissipative soliton (DS) mode-locking may be one of the efficient solutions. In this chapter, the current state of the art in high-energy ultrafast DS 2 μm TDFLs developed in our laboratory is reviewed, and the potential and prospect of this theme are analyzed. By introducing a new model, condensed-gain fiber mode-locking, we show that the soliton pulse energy of 2 μm TDFLs can be steadily scaled to over 10 nJ and various soliton dynamics (harmonic mode-locking, soliton molecules, etc.) can be observed. Furthermore, DS mode-locking of TDFLs with one of the two-dimension-like materials (MoS2) is investigated

Aflatoxin B1, zearalenone and deoxynivalenol in feed ingredients and complete feed from different Province in China

Abstract Background The current study was carried out to provide a reference for monitory of aflatoxin B1 (AFB1), zearalenone (ZEN) and deoxynivalenol (DON) contamination in feed ingredients and complete feeds were collected from different Province in China from 2013 to 2015. Methods A total of 443 feed ingredients, including 220 corn, 24 wheat, 24 domestic distillers dried grains with soluble (DDGS), 55 bran, 20 wheat shorts and red dog, 37 imported DDGS, 34 corn germ meal and 29 soybean meal as well as 127 complete feeds including 25 pig complete feed (powder), 90 pig complete feed (pellet), six duck complete feed and six cattle complete feed were randomly collected from different Province in China, respectively, by high-performance chromatography in combined with UV or fluorescence analysis. Results The incidence rates of AFB1, ZEN and DON contamination of feed ingredients and complete feeds were 80.8, 92.3 and 93.9 %, respectively. The percentage of positive samples for DON ranged from 66.7 to 100 %. Domestic DDGS and imported DDGS presented the most serious contamination AFB1, ZEN and DON contamination levels of feeds ranged from 61.5 to 100 %, indicated that serious contamination over the studied 3-year period. Conclusion The current data provide clear evidence that AFB1, ZEN and DON contamination of feed ingredients and complete feeds in different Province in China is serious and differs over past 3-year. The use of corn, domestic DDGS, imported DDGS and corn germ meal, which may be contaminated with these three mycotoxins, as animal feed may triggered a health risk for animal. Feeds are most contaminated with DON followed by ZEN and AFB1. Mycotoxins contamination in feed ingredients and complete feeds should be monitored routinely in China