In plant genetic engineering, selectable marker is needed to distinguish transformant. As the commercialization of transgenic plants, people are more and more paying close attention to their safety, among which mainly refers to the safety of selectable marker. In order to increase the safety of transgenic plants, biologists began to search for biosafe selectable marker.Current research progress of taking key enzyme in metabolic pathways were overviewed,which include glycometabolism, amino acid metabolism, hormone metabolism ,nucleotide metabolism and protein metabolism et cetera, as selectable marker in transgenic plants.

Female ; Head and Neck Neoplasms ; pathology ; Humans ; Infant ; Teratoma ; pathology

The rodipicolinate synthase gene was cloned from Nicotiana tabacum L.cv,which encodes the key enzyme in the synthesis of lysine,and then a vitro molecular reform reliefing feedback suppression was made. Some resistant seedlings were acquired using the mutated gene as selectable marker and analog of lysine as selectable reagent,and the detection results were positive by means of PCR and Real-Time PCR,however the phenotype is somewhat abnormal.

OBJECTIVE: To suppress NgR gene expression in neural stem cells and observe differentiation of neural stem cells in vitro after interfered which provide nutritional support for the facial nerve repair in vivo. METHOD: PCR amplification, restriction endonuclease digestion, T4DNA ligase connections were used to connected NgR with rector pGCsi, and constructed recombinant vector (NgR shRNA). Lipofectamine 2000 were used to transfect the NSC. The expression of NgR was examined by Western Blot. The proportion of neural stem cells transformed into neurons after transfection was tested by Immunocytochemistry. Neural stem cells were planted in PLGA tubes after transfected, and were scanned by electron microscopy. RESULT: NgR shRNA plasmid was constructed and infected neural stem cells successfully. Western Blot showed that the expression of NgR decreased in neural stem cells after interference. Immunocytochemistry showed that the rate of the neural stem cells transformed into neurons after interfered was significantly higher (P < 0.01). CONCLUSION Neural stem cells were transformed into neurons after NgR shRNA plasmid infected neural stem cells, which promoted axonal regeneration more effectively and provided a efficient and stable gene platform for facial nerve repair.
Animals ; Cell Differentiation ; Cells, Cultured ; Facial Nerve ; surgery ; GPI-Linked Proteins ; genetics ; metabolism ; Myelin Proteins ; genetics ; metabolism ; Neural Stem Cells ; cytology ; metabolism ; Nogo Receptor 1 ; RNA Interference ; Rats ; Rats, Sprague-Dawley ; Receptors, Cell Surface ; genetics ; metabolism

Aged ; Apoptosis ; physiology ; Carcinoma, Squamous Cell ; genetics ; Cell Cycle ; Female ; Gene Expression Profiling ; Humans ; Laryngeal Neoplasms ; genetics ; Male ; Middle Aged ; Oligonucleotide Array Sequence Analysis ; Signal Transduction

Objective To optimize and establish the methodology for culturing and inducing differentiation of mouse preadipocytes 3T3-L1. Methods The mouse cells 3T3-L1 were incubated in DMEM medium contained with 10%FBS, during which the incubation medium was refreshed every 2 to 3 days. Two methods were used to introduce differentiation, including three-drug combination group and four-drug combination group. The protocol of mediumⅠin three-drug combination group including insulin 10 mg/L, IBMX 0.5 mmol/L and DEX 1.0μmol/L. The protocol of mediumⅠin four-drug combination group including indometacin 0.1 mmol/L based on those of three-drug combination group. Both of them were incubated for 2 days and continuous for 2 times. And medium Ⅱ included insulin 10 mg/L for 2-day culturing and continuous for 2 times. Oil red O staining was used to observe the morphological changes of two groups of cells before and after treatment under inverted microscope. Results Mouse preadipocytes 3T3-L1 appeared in good conditions and grew in a paving stone fashion. These cells covered homogeneously the bottom of incubators, the culture medium refreshed every 2 days. The results of four-drug combination group were better than those of three-drug combination group. After three-drug combination induced differentiation, there was no significant change in cell morphology. Comparing with three-drug combination induced differentiation, four-drug combination was successfully achieved in over 90% of the cell inducing, which were round-shaped, with jacinth ester droplets by oil-red O staining. Conclusion We have optimized the method for culturing and inducing differentiation of mouse preadipocytes 3T3-L1 by adding indometacin on the basis of the three-drug combination induced differentiation.

Pseudomonas sp. TS1138 isolated from soil samples was able to form L-cysteine from DL-2-Amino-△2-Thia-zoline-4-Carboxylic Acid (DL-ATC) after cultured 16 hours . The optimum carbon and nitrogen soruces of strain growth and enzyme formation are glucose and urea. This enzyme was induced by DL-ATC. The product was identified to be L-Cysteine based on thin layer chromatography, optical rotation and HPLC studies.

Objective To explore the clinical value of renal dynamic imaging and urinary N-acetyl-?-D-glucosaminidase(NAG),apoptosis DNA fragment(ADF) in evaluating the damage degree of hydronephrotic kidneys(HnK) in children with hydronephrosis.Methods Level of glomerular filtration rate(GFR) was detected in 41 children with congenital hydronephrosis by renal dynamic imaging,and urine NAG,ADF in pelvis in HnK and healthy kidneys (as controls) were detected by enzyme-linked immuno-sorbent assay(ELISA).Patholo-gic changes of HnK in 41 children were graded intoⅠ~Ⅴ according to Elder standard. And GFR,urinary NAG and ADF of HnK were divi-ded into subgroup according to pathologic changes ,at the same time statistical analysis was performed within each groups. And the correlations of pathologic grades with GFR,urinary NAG and ADF of HnK were analyzed.Results 1.Kindneys GFR in healthy kidneys and Hnk were (174.33?20.43)?10-3 L/min,(143.86?17.51)?10-3 L/min respectinely,and there was significant difference between healthy kidneys and Hnk (P0.05).3.There was significant negative correlation between GFR levels of HnK and pathologic grades(r=-0.814 P0.05).Conclusions For hydronephrotic kidneys,urinary NAG can eva-luate impaired nephric tubule whereas renal dynamic imaging may evaluate the damage level of glomeruli;urine ADF may not indicate the damage level of diseased kidneys in children with congenital hydronephrosis.

BACKGROUND: Cell therapy, recombinant proteins and biomacromolecule preparations have been widely used in clinical practice; however, transplant rejections caused by xenogeneic proteins limit the safe and reusable use of such macromolecules. OBJECTIVE: To review the immunocamouflage mechanism of polyethylene glycol and the current application in the modification of macromolecules or biological vectors. METHODS: The authors retrieved articles about the immune camouflage of polyethylene glycol in WanFang, VIP and PubMed databases by the keywords as follows: "polyethylene glycol; immunocamouflage or immune camouflage; transplantation, and rejection" in Chinese and English, respectively. RESULTS AND CONCLUSION: Polyethylene glycol produces an immune camouflage by forming a stereoscopic charge barrier. The pegylation on the cell surface inhibits the adhesion, recognition and immune pathway involved in the heterogeneous recognition, which can interfere with many aspects of the immune response. The pegylated erythrocytes, islet cells, and lymphocytes show a decrease in the immunogenicity and a prolonged survival after allogeneic or xenotransplantation. Some factors including concentration, molecular weight, modification time, pH value can affect the immune camouflage of polyethylene glycol. The anti-PEG antibody and its effects need to be further elucidated.