Objective To investigate the localization and distribution of the five endocrine cells in the digestive tract mucosa of ricefield eel(Monopterus albus). Methods Using immunocytochemical technique of strept avidin-biotin-peroxidase complex(SABC) were used. Results At least 5 kinds of immunoreactive endocrine cells distributed in the digestive tract mucosa of M.albus. They were gastrin(Gas),somatostatin(Som),5-hydroxytryptamine(5-HT),insulin(Ins),and neurofilament (NF) immunoreactive endocrine(IRE) cells.Gas and Som-IRE cells distributed between stratified squamous epithelium and goblet cell in esophagus. A large number of Gas-IRE cells were found between gastric fundus epithelium and gastric glands, and only a few in the carcia. Ins, 5-HT and NF-IRE cells distributed in the epithelium pylorus and pyloric glandular tube respectively. No any immunoreactive positive reaction was found in the gut of M.albus.In addition, immunoreactive positive reaction of glucagons was not found in whole digestive tract.All immunoreactive endocrine cells were dark brown in color.Their morphology was irregular, cytoplasmic process was shorter and thicker, their nucleus showed an empty bubble.They distributed between esophageal epithelium and gastric epithelium or glandular epithelium, and cytoplasmic process extended to the gastric lumen and glandular cavity.Conclusion There is a complex endocrine function of the digestive system in ricefield eel (M.albus) at the lowest vertebrate.

Objective To explore the correlation between axon guidance factor Semaphorin 5A and clinicopathological features and its role in the invasion and metastasis of gastric cancer.Methods The expression of Semaphorin 5A in gastric cancer tissues of 171 patients with different gender,age,histological type and TNM stage was detected with immunohistochemistry assay.The expression of Semaphorin 5A was determined by Western blotting assay in gastric cancer cell lines SGC7901 and MKN-45 with metastatic ability and gastric cancer cell lines SNU-1 and AGS without metastatic ability.With RNA interfere technique(RNAi),Semaphorin 5A siRNA expression vector was constructed and transfected into gastric cancer cell line SGC7901.The stable gastric cancer cell line down-expressing Semaphorin 5A was established.The effect of Semaphorin 5A gene silencing on the adhesion,migration and invasion of gastric cancer cell was examined by cell adhesion test,wound healing test and transwell chamber assays.Results The expression level of Semaphorin 5A was correlated with the differentiation degree of gastric cancer(x2 =6.32,P =0.01),lymphnode metastasis(x2 =7.68,P=0.01)and distant metastasis of gastric cancer(x2 =13.67,P =0.00),not correlated with age(x2 =0.21,P=0.79),gender(x2=1.79,P=0.15)and the depth of gastric cancer invasion(x2=1.34,P=0.55).The expression of Semaphorin 5A in cell lines SGC7901 and MKN-45 was significantly higher than that of cell lines SNU-1 and AGS(P＜0.01).Semaphorin 5A gene silencing significantly suppressed the adhesion,migration and invasion abilities of gastric cancer cells.Conclusion Semaphorin 5A may play a catalytic role in the invasion and metastasis of gastric cancer through increasing the adhesion,migration and invasion abilities of gastric cancer cell.

Objective: To investigate the apoptotic effects and its mechanisms on K562 cells caused by Interferon-alpha (INF-?) and Cytarabine (Ara-C). Methods: The variation of both morphology and inhibitory rate of K562 cells was observed in culture medium with IFN-? and various concentrations of Ara-C at different time in vitro. The variation of telomerase activity and P53 protein expression were detected before and after apoptosis occurred. Results: INF-? and Ara-C used concurrently could cause apoptosis and inhibit the growth of K562 cells as well as decrease the telomerase activity and increase P53 protein expression significantly. All these processes showed both in time- and dose-dependent manner. Conclusions: INF-? and Ara-C used concurrently can inhibit the growth of K562 cells and induce apoptosis, inhibiting the telomerase activity and increasing the expression of P53 protein may be one of the most important mechanisms.

Superoxide dismutase (SOD) family is necessary to protect cells from the toxicity of reactive oxygen species produced during normal metabolism. Among SODs, manganese-containing superoxide dismutase (Mn-SOD, SOD2) is the most important one. The DNA fragment containing the full nucleotide of full-length human SOD2 was synthesized and inserted into the prokaryotic expression vector pGEX-4T-1 with tag GST. DNA construct was then transformed into Escherichia coli BL21 (DE3) and expression was induced with IPTG at 25 ℃. The recombinant fusion protein GST-SOD2 (46 kDa) was purified from the bacterial lysate by GST resin column affinity chromatography. GST tag was cleaved with thrombin, and a crude SOD2 recombinant protein (25 kDa) was obtained and further purified by heparin affinity chromatography. Activities of the two SOD2 proteins were 1 788 and 2 000 U/mg, respectively. Both SOD2 proteins were stable under physiological condition and cell-penetrating (P<0.05). Our findings open the possibility to study the structure and effects of two full-length recombinant SOD2 proteins.

Two proteins of similar molecular weight (named as ASPR-C-1 and ASPR-C-2) from the crude drug of Angelica sinensis were purified and characterized by 80% ammonium sulfate precipitation, Sephadex G-50 gel filtration chromatography, and DEAE-Sepharose anion exchange chromatography. The molecular weight of ASPR-C-1 and ASPR-C-2 on SDS-PAGE was 17.33 kDa and 17.18 kDa, respectively. They were mainly monomeric in solution, but partially formed dimers and they were glycoproteins with glycosyl content of 2.6% and 8.2%, respectively. Both ASPR-C-1 and ASPR-C-2 were identified to be members of pathogenesis-related 10 family of proteins by matrix-assisted laser desorption ionization time-of-flight mass spectrometry and have ribonuclease activities with the specific activity of 73.60 U/mg and 146.76 U/mg, respectively. The optimum pH of the two isoforms was similar, at about 5.6, while their optimum temperatures were different. The optimum temperature of ASPR-C-1 was 50 ℃, and that of ASPR-C-2 was 60 ℃. Both isoforms presented highest thermal stability at 60 ℃. However, ASPR-C-2 was more thermotolerant than ASPR-C-1. The latter was rapidly inactivated and retained only about 20% residual activity while the former still maintained about 80% of its original activity at a higher treatment temperature (80 to 100 ℃). In addition, Fe²⁺ had an activating effect on the ribonuclease activities of two isoforms while Ca²⁺, Mg²⁺, Zn²⁺, Mn²⁺, Ag⁺, Cu²⁺, EDTA (Elhylene diamine tetraacetic acid), dithiothreitol and sodium dodecylsulphate showed different degrees of inhibition of the enzyme activities. Our findings provide a foundation for further research on the biological function of PR-10 protein from Angelica sinensis.
Angelica sinensis ; Chromatography, Gel ; Chromatography, Ion Exchange ; Electrophoresis, Polyacrylamide Gel ; Enzyme Stability ; Hydrogen-Ion Concentration ; Kinetics ; Molecular Weight ; Protein Isoforms ; Temperature