受体介导内吞引起的巨噬细胞胞质酸化和胞吐作用

本文利用激光扫描共聚焦显微镜A-CAS570从细胞形态学和功能两方面,研究了刀豆素A(Concanavalin A,Con A)、麦芽凝集素(Wheat Germ Agglutinin,WGA)、酵母多糖(Zymosan A,Z.A)对小鼠腹腔巨噬细胞胞质pH和溶酶体内荧光探针FITC—Dextran排出细胞的影响。结果显示三种配体加入细胞外液10min内,胞质pH很快下降,此后维持在该水平;在15min左右细胞外FITC一Dextran迅速增加,20min后变化趋于停止;在三种配体加入后15min左右,细胞内溶酶体在质膜内侧增多;25—30min溶酶体重新向细胞中央运动。根据上述实验结果,我们认为溶酶体pH升高是触发溶酶体内荧光探针通过胞吐作用排出细胞的必要条件,胞质酸化抑制溶酶体内容物通过胞吐作用排出细胞。配体刺激引起的溶酶体内容物通过胞吐作用排出细胞和胞质酸化是细胞自我调节和保护的一种反映。

Research on Physical and Chemical Properties of Corynebacterium glutamicum in Fermentation Process of the Glucose of Wheat Starch

[Objective] This study aimed to investigate the physical and chemical char- acteristic of Corynebacterium glutamicum in fermentation process of the glucose of wheat starch. [Method] The purity of glutamic acid in fermentation period, optical density and cell viability of bacteria were detected as indicators for regression com- parison and analysis. [Result] The relative error d=-3.316 6% within the experimental range of Warburg trace breathing apparatus and double function analyzer. The linear relationship was s1=（1-d）s2. During the fermentation process of the glucose of wheat starch, the average cell activity was 6.24 μA and the maximum cell activity was 6.61 μA. [Conclusion] Compared with optical density, cell viability can more accurate- ly reflect the physical and chemical properties of Corynebacterium glutamicum in fermentation process of the glucose of wheat starch. There was certain correlation between cell membrane phospholipids and cell viability.

Effect of Low-pressure Carbonation on the Heat Inactivation and Cytoplasmic Acidification of Saccharomyces cerevisiae

Effect of low-pressure carbonation （LPC） on heat inactivation of Saccharomyces cerevisiae was investigated. The cell suspension was carbonated at 1 MPa and 4℃ for 15 min and subsequently heated from 51 to 61 ℃ and 5 s to 5 min （heating with LPC）. As a control experiment, cell suspension was heat-treated under atmospheric pressure without LPC （heating）. The inactivation ratio of heating at 53℃ and 55℃ for l rain with LPC was approximately 1 log order higher than heating alone. Extending heating time to 5 min did not widen the difference in the inactivation ratio between heating with LPC and heating alone at both heating temperatures. At 57℃, the difference in inactivation ratio increased from 1 to 2.5 log order with extending treatment time from 5 to 15 s. The results suggested that the enhanced inactivation effect by LPC was obtained at the higher temperature with short time treatment than the lower temperature with longer time treatment. Under fluorescence microscope observation of LPC-treated cell stained with LysoSensor probe, it seemed that LPC was hardly able to acidify the cytoplasm ofS. cerevisiae. It is considered that the ability orS. cerevisiae ceils to keep their cytoplasmic pH during LPC resulted in the inferior increase in heat inactivation ratio by LPC as compared with bacteria in the previous studies.

Resected case of eosinophilic cholangiopathy presenting with secondary sclerosing cholangitis

Eosinophilic cholangiopathy is a rare condition characterized by eosinophilic infiltration of the biliary tract and causes sclerosing cholangitis. We report a patient with secondary sclerosing cholangitis with eosinophilic cholecystitis. A 46-year-old Japanese man was admitted to our hospital with jaundice. Computed tomography revealed dilatation of both the intrahepatic and extrahepatic bile ducts, diffuse thickening of the wall of the extrahepatic bile duct, and thickening of the gallbladder wall. Under the diagnosis of lower bile duct carcinoma, he underwent pyloruspreserving pancreatoduodenectomy and liver biopsy. On histopathological examination, conspicuous fibrosis was seen in the lower bile duct wall. In the gallbladder wall, marked eosinophilic infiltration was seen. Liver biopsy revealed mild portal fibrosis. He was diagnosed as definite eosinophilic cholecystitis with sclerosing cholangitis with unknown etiology. The possible etiology of sderosing cholangitis was consequent fibrosis from previous eosinophilic infiltration in the bile duct. The clinicopathological findings of our case and a literature review indicated that eosinophilic cholangiopathy could cause a condition mimicking primary sclerosing cholangitis （PSC）. Bile duct wall thickening in patients with eosinophilic cholangitis might be due to fibrosis of the bile duct wall. Eosinophilic cholangiopathy might be confused as PSC with eosinophilia.

All-trans Retinoic Acid Induced the Differentiation of Human Glioma Cells

OBJECTIVE To observe the effect of all-trans retinoic acid （ATRA） on inducing human glioma MO59K cells differentiation and further explore the underlying molecular mechanisms.METHODS The expression of glial fibrillary acidic protein （GFAP） was detected by immunocytochemistry staining. The mRNA levels of GFAP, retinoid X receptor α（RXRα）, p21 were examined by semi-quantitative RT-PCR analysis. Luciferase activity assay was performed in the COS-7, MO59K cells to measure p21 promoter transcription activity.RESULTS ATRA could significantly enhance the expression and mRNA level of GFAP by immunostaining and RT-PCR （P〈0.05）. Simultaneously, the mRNA levels of RXRα and p21 were remarkably increased in dose-dependent manner by RT-PCR （P〈0.05）. Furthermore, luciferase assay confirmed that ATRA and RXRα could transactivate p21 promoter in COS-7 and glioma cells （P〈0.05）.CONCLUSION ATRA can induce differentiation of human glioma cells. The RXRα and p21 were activated during ATRAinduced differentiation process. This effect may be caused by directly RXRα-induced p21 gene transactivation. Our findings provide novel evidence for the future studies to explore the molecular mechanism of transcriptional regulation for glioma cell differentiation and cellular therapeutic approaches for glioblastoma.

Effect of basic fibroblast growth factor on the expression of glial fibrillary acidic protein after tractive spinal cord injury in rats

OBJECTIVE: To investigate the effects of basic fibroblast growth factor (bFGF) on the expression of glial fibrillary acidic protein (GFAP) after tractive spinal cord injury in rats and to explore the recovery of spinal cord function. METHODS: The rats were subjected to tractive spinal cord injury at T13-L2. Cortical somatosensory-evoked potential (CSEP) was closely monitored and when P1-N1 wave amplitude decreased to 70% of that before operation, a small-bore catheter was inserted below the injured plane through subarachnoid cavity. In the treatment groups, 20 microl of bFGF solution (containing 20 microg of bFGF) was injected through the catheter right after the operation and 1, 2, 3, 4, 8, 12 and 24 h postoperatively. In the control group, same volume of normal saline was injected and every four rats were killed at 1, 4, 7, 14 and 21 d after the operation. Combined behavior score (CBS) and electro-physiological examination were adopted to evaluate function recovery. Expression of GFAP was observed by immuno-histochemical staining and was analyzed quantitatively by computer image analysis. RESULTS: There was statistically significant difference in GFAP-positive cells between bFGF treatment group and the control group (P

TFIIA transcriptional activity is controlled by a ＇cleave-and-run＇ Exportin-1/Taspase 1-switc

Transcription factor TFIIA is controlled by complex regulatory networks including proteolysis by the protease Taspase 1, though the full impact of cleavage remains elusive. Here, we demonstrate that in contrast to the general assumption, de novo produced TFIIA is rapidly confined to the cytoplasm via an evolutionary conserved nuclear export signal （NES, amino acids ^21VINDVRDIFL^30）, interacting with the nuclear export receptor Exportin-1/chromosomal region maintenance 1 （Crml）. Chemical export inhibition or genetic inactivation of the NES not only promotes TFIIA＇s nuclear localization but also affects its transcrip- tional activity. Notably, Taspase 1 processing promotes TFIIA＇s nuclear accumulation by NES masking, and modulates its tran- scriptional activity. Moreover, TFIIA complex formation with the TATA box binding protein （TBP） is cooperatively enhanced by inhibition of proteolysis and nuclear export, leading to an increase of the ceil cycle inhibitor p16INK, which is counteracted by pre- vention of TBP binding. We here identified a novel mechanism how proteolysis and nuclear transport cooperatively fine-tune tran- scriptional programs.

Chemical synthesis of glycoproteins

Recently, there has been an overwhelming demand for studies on protein post-translational modification （PTM） to understand the increasing complexity from the level of the genome to the proteome. The covalent modifications of proteins with phosphates, lipids, sugars or other residues confer on these proteins additional structural and functional diversity. For instance, protein phosphorylation is involved in a wide range of cellular processes including signal transduction. Protein glycosylation is one of the most abundant PTMs and more than 50% of all human proteins are glycosylated. Glycoproteins are involved in many biological events, such as cell-cell adhesion, communication, immune response and development.

Inhibition of adipogenic differentiation by myostatin is alleviated by arginine supplementation in porcine-muscle-derived mesenchymal stem cells

Porcine mesenchymal stem cells in postnatal muscle have been demonstrated to differentiate into adipocytes. This increases adipocyte number and lipid accumulation, and is thought to be the origin of intramuscular fat. In this study, the effects of myostatin and arginine on adipogenic differentiation in mesenchymal stem cells derived from porcine muscle （pMDSCs） were investigated in vitro. Intracellular triglyceride levels were reduced by exogenous myostatin and increased by arginine supplementation or myostatin antibody （P〈0.01）. The inhibition of lipid accumulation by rnyostatin in pMDSCs was alleviated by arginine supplementation （P〈0.01）. Expression patterns of adipogenic transcription factors showed that exogenous myostatin suppressed PPAR72 and aP2 expression （P〈0.01）, while supplemental arginine or myostatin antibody promoted ADD1 expression （P〈0.01）. Furthermore, compared with the addition of either myostatin protein or antibody alone, ADD1 and PPARδ expression were promoted by the combination of arginine and myostatin （P〈0.01）, and arginine combined with myostatin antibody promoted the expression of ADD1, PPARδ, C/EBPα, PPARγ2 and LPL in pMDSCs （P〈0.05）. These results suggest that myostatin inhibits adipogenesis in pMDSCs, and that this can be alleviated by arginine supplementation, at least in part, through promoting ADD1 and PPARδ expression.