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Kinetics of selenium absorption in ligated small intestinal loops of chicks
LIU Guo-qing, ZHANG Shu-min, AN Zhi-min, FENG Yan-zhong, DONG Xue-yu, LI Su-fen, LU Lin, ZHANG Li-yang, WANG Run-lian, LUO Xu-gang, LIAO Xiu-dong
2020, 19 (8): 2095-2102.   DOI: 10.1016/S2095-3119(20)63194-X
Abstract135)      PDF in ScienceDirect      
Selenium (Se) is an essential trace element that has a large number of biological functions for broilers.  However, the absorption kinetics of Se from sodium selenite in the small intestine of broilers remains unclear.  Therefore, two experiments were conducted with 28-d-old commercial male broilers to study the kinetics of Se absorption in ligated small intestinal segments.  In experiment 1, the Se absorption in duodenal, jejunal, and ileal segments at different post-perfusion time points (0, 20, 40, 60, 80, 100 and 120 min) were compared.  In experiment 2, a kinetic study of Se absorption was conducted with the duodenal, jejunal, and ileal loops perfused with solutions containing 0, 0.0375, 0.075, 0.15, 0.30, or 0.60 μg mL–1 of Se as sodium selenite, and Se contents in perfusates were determined at 100 min after perfusion.  The results from experiment 1 showed that the Se absorption increased in an asymptotic response (P<0.0001) to post-perfusion time within 120 min in all the small intestinal segments, but increased linearly (P<0.0001) at less than 100 min after perfusion in duodenal and ileal segments, while more than 96.0% of the maximum Se absorption occurred at 100 min after perfusion in each small intestinal segment.  In experiment 2, there was no difference (P>0.05) in the Se absorption rate among different ligated small intestinal segments perfused with solutions containing 0.0375–0.15 μg mL–1 of Se, however, the Se absorption rate was higher (P<0.05) in the jejunum than that in the duodenum perfused with solutions containing 0.30–0.60 μg mL–1 of Se.  The kinetic curves of Se absorption demonstrated that the Se absorption was a saturated carrier-mediated process in the duodenum, and the maximum absorption rate was 1 271 pg min–1 cm–1; whereas the Se absorptions were a non-saturated diffusion process in the jejunum and ileum, and the diffusive constants were 2 107 and 1 777 cm2 min–1, respectively.  The results from the present study indicate that the jejunum is the main Se absorption site, and the Se absorption is a saturated carrier-mediated process in the duodenum, but a non-saturated diffusion process in the jejunum and ileum of broilers.
 
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ALK Family Inhibitor A83-01 Promotes the Proliferation of Mouse Male Germline Stem Cells (mGSCs) Under Serum- and Feeder-Free Conditions
YU Meng, WANG Long, HU Yue, LIAN Zhi-min , HUA Jin-lian
2013, 12 (10): 1839-1846.   DOI: 10.1016/S2095-3119(13)60413-X
Abstract1379)      PDF in ScienceDirect      
A83-01 is a selective inhibitor of the TGF-β type I receptor ALK, which inhibits the TGF-β-induced epithelial-to-mesenchymal transition (EMT) via the inhibition of Smad2 phosphorylation. Previous studies have showed that A83-01 promoted somatic cellular reprogramming significantly. Male germline stem cells (mGSCs), as an alternative resource of pluripotent stem cells derived adult testis, have promising valuable in clinic medicine and regeneration, however, the derivation of mGSCs was complex and difficult. What the role A83-01 plays in promoting the proliferation of mGSCs is still unknown. In this study, combined with A83-01 and knockout serum replacement (KSR) medium, we obtained a relatively feeder- and serum-free system for mGSCs culturing in vitro and the optimal concentration of A83-01 was 0.25 μmol L-1. After continuous culturing, the proliferation efficiency of undifferentiated mGSCs and differentiation capacity of mGSC were examined as well. Results showed that, A83-01 dramatically increased the number of mGSCs and AP positive colonies, and the mitosis index according to the BrdU assay. A83-01 could also increase the expression of pluripotent markers including Oct4, Klf4, Nanog and c-Myc, analyzed by real-time quantative PCR. mGSCs cultured in the optimal feeder-and serum-free system combined with A83-01 could form embryoid bodies (EBs), which consisted of three embryonic layers detected by immunofluorescence and RT-PCR. Remarkably, the results demonstrated 0.25 μmol L-1 A83-01 could promote the proliferation of mouse mGSC colonies and maintain their undifferentiated status under feeder- and serum-free systems.
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