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961.
Young Bong Choi Myoungsun Son Mijin Park Jaekyoon Shin Yungdae Yun 《The Journal of biological chemistry》2010,285(10):7271-7280
The T cell-specific tyrosine kinase, p56lck, plays crucial roles in T cell receptor (TCR)-mediated T cell activation. Here, we report that SOCS-6 (suppressor of cytokine signaling-6) is a negative regulator of p56lck. SOCS-6 was identified as a protein binding to the kinase domain of p56lck through yeast two-hybrid screening. SOCS-6 bound specifically to p56lck (F505), which mimics the active form of p56lck, but not to wild type p56lck. In Jurkat T cells, SOCS-6 binding to p56lck was detected 1–2 h after TCR stimulation. Confocal microscopy showed that upon APC-T cell conjugation, SOCS-6 was recruited to the immunological synapse and colocalized with the active form of p56lck. SOCS-6 promoted p56lck ubiquitination and its subsequent targeting to the proteasome. Moreover, SOCS-6 overexpression led to repression of TCR-dependent interleukin-2 promoter activity. These results establish that SOCS-6 acts as a negative regulator of T cell activation by promoting ubiquitin-dependent proteolysis. 相似文献
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964.
Kim YM Lee SE Park BS Son MK Jung YM Yang SO Choi HK Hur SH Yum JH 《International journal of biological sciences》2012,8(1):66-78
Mass production of glucosamine (GlcN) using microbial cells is a worthy approach to increase added values and keep safety problems in GlcN production process. Prior to set up a microbial cellular platform, this study was to assess acetate metabolism in Citrobacter sp. BL-4 (BL-4) which has produced a polyglucosamine PGB-2. The LC-MS analysis was conducted after protein separation on the 1D-PAGE to accomplish the purpose of this study. 280 proteins were totally identified and 188 proteins were separated as acetate-related proteins in BL-4. Acetate was converted to acetyl-CoA by acetyl-CoA synthetase up-regulated in the acetate medium. The glyoxylate bypass in the acetate medium was up-regulated with over-expression of isocitrate lyases and 2D-PAGE confirmed this differential expression. Using (1)H-NMR analysis, the product of isocitrate lyases, succinate, increased about 15 times in the acetate medium. During acetate metabolism proteins involved in the lipid metabolism and hexosamine biosynthesis were over-expressed in the acetate medium, while proteins involved in TCA cycle, pentose phosphate cycle and purine metabolism were down-regulated. Taken together, the results from the proteomic analysis can be applied to improve GlcN production and to develop metabolic engineering in BL-4. 相似文献
965.
Isabelle Lardon Göran E. Nilsson Jonathan A. W. Stecyk Trung Nghia Vu Kris Laukens Roger Dommisse Gudrun De Boeck 《Metabolomics : Official journal of the Metabolomic Society》2013,9(2):311-323
The crucian carp (Carassius carassius) can tolerate anoxia for days to months, depending on the temperature. In this study, we applied 1H-NMR-based metabolomics to polar extracts of crucian carp brain, heart, muscle and liver samples obtained from fish exposed to either control normoxic conditions, acute anoxia (24 h), chronic anoxia (1 week) or reoxygenation (for 1 week following chronic anoxia) at 5 °C. Spectra of the examined tissues revealed changes in several energy-related compounds. In particular, anoxic stress resulted in decreased concentrations of phosphocreatine (muscle, liver) and glycogen (liver) and ATP/ADP (liver, heart and muscle) and increased concentrations of lactate (brain, heart, muscle) and beta-hydroxybutyric acid (all tissues). Likewise, increased concentrations of inhibitory compounds (glycine, gamma-amino butyric acid or GABA) and decreased concentrations of excitatory metabolites (glutamate, glutamine) were confirmed in the anoxic brain extracts. Additionally, a decrease of N-acetylaspartate (NAA), an important neuronal marker, was also observed in anoxic brains. The branched-chain amino acids (BCAA) valine/isoleucine/leucine increased in all anoxic tissues. Possibly, this general tissue increase can be due to an inhibited mitochondrial function or due to protein degradation/protein synthesis inhibition. In this study, the potential and strength of the 1H-NMR is highlighted by the detection of previously unrecognized changes in metabolites. Specifically, myo-inositol substantially decreased in the heart of anoxic crucian carp and anoxic muscle tissue displayed a decreased concentration of taurine, providing novel insights into the anoxia responses of the crucian carp. 相似文献
966.
Spherical three-dimensional cell aggregates called embryoid bodies (EBs), have been widely used in in vitro differentiation protocols for human pluripotent stem cells including human embryonic stem cells (hESCs) and human induced pluripotent stem cells (hiPSCs). Recent studies highlight the new devices and techniques for hEB formation and expansion, but are not involved in the passaging or subculture process. Here, we provide evidence that a simple periodic passaging markedly improved hEB culture condition and thus allowed the size-controlled, mass production of human embryoid bodies (hEBs) derived from both hESCs and hiPSCs. hEBs maintained in prolonged suspension culture without passaging (>2 weeks) showed a progressive decrease in the cell growth and proliferation and increase in the apoptosis compared to 7-day-old hEBs. However, when serially passaged in suspension, hEB cell populations were significantly increased in number while maintaining the normal rates of cell proliferation and apoptosis and the differentiation potential. Uniform-sized hEBs produced by manual passaging using a 1∶4 split ratio have been successfully maintained for over 20 continuous passages. The passaging culture method of hEBs, which is simple, readily expandable, and reproducible, could be a powerful tool for improving a robust and scalable in vitro differentiation system of human pluripotent stem cells. 相似文献
967.
Choi Sung Mee Ho Son Sung Rho Yun Seung Woung Kwon Oh Hoon Seon Jeong Yoeup Paek Kee 《Plant Cell, Tissue and Organ Culture》2000,62(3):187-193
A pilot-scale culture of multiple adventitious roots of ginseng was established using a balloon-type bubble bioreactor. Adventitious
roots (2 cm) induced from callus were cultured in plastic Petri dishes having 20 ml of solid Schenk and Hildebrandt (1972)
medium containing 3% sucrose, 0.15% gelrite, and 24.6 μM indole-3-butric acid. An average of 29 secondary multiple adventitious
roots were produced after 4 weeks of culture. These secondary roots were elongated on the same medium, reaching a length of
5 cm after 6 weeks of culture. A time course study revealed that maximum yields in 5-l and 20-l bioreactors were approximately
500 g and 2.2 kg at day 42 with 60 g and 240 g inoculations, respectively. Cutting twice during the culture increased the
total amount of biomass produced. The root biomass in a 20-l balloon-type bubble bioreactor was 2.8 kg at harvest with 240
g of inoculum after 8 weeks of culture. The total saponin content obtained from small-scale and pilot-scale balloon type bubble
bioreactors was around 1% based on dry weight. Inoculation of 500 g fresh weight of multiple adventitious roots into a 500
l balloon-type bubble bioreactor with cutting at 4 and 6 weeks after inoculation produced approximately 74.8 kg of multiple
roots. The ginsengnoside profiles of these multiple adventitious roots were similar to profiles of field-grown ginseng roots
when analyzed by HPLC.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
968.
Previously, we identified a novel herbivore elicitor-regulated protein in Nicotiana attenuata (NaHER1) that is required to suppress abscisic acid (ABA) catabolism during herbivore attack and activate a full defense response against herbivores. ABA, in addition to its newly defined role in defense activation, mainly controls seed germination and stomatal function of land plants. Here we show that N. attenuata seeds silenced in the expression of NaHER1 by RNA interference (irHER1) accumulated less ABA during germination, and germinated faster on ABA-containing media compared to WT. Curiously, epidermal cells of irHER1 plants were wrinkled, possibly due to the previously demonstrated increase in transpiration of irHER1 plants that may affect turgor and cause wrinkling of the cells. We conclude that NaHER1 is a highly pleiotropic regulator of ABA responses in N. attenuata plants. 相似文献
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970.