Development of a direct transformation method by GFP screening and in vitro whole plant regeneration of Capsicum frutescens L

Background: Capsicum is a genus of an important spice crop that belongs to the chili lineage. However, many Capsicum species (family Solanaceae) are known to be recalcitrant to genetic transformation and in vitro regeneration, thus hampering the effort in using Capsicum species for detailed biological investigation. In this study, we have developed an optimized protocol for the direct transformation of Capsicum frutescens L. cv. Hot Lava using a biolistic particle delivery system. In addition, a procedure for in vitro whole plant regeneration from the hypocotyl explants of C. frutescens was established. Results: In this study on the biolistic system, explant target distance, bombardment helium (He) pressure, and the size of the microcarrier were the key parameters to be investigated. The optimized parameters based on the screening of GFP expression were determined to have a target distance of 6 cm, helium pressure of 1350 psi, and gold particle (microcarrier) size of 1.6 µm. The greatest number of shoots was obtained from hypocotyls as explants using Murashige and Skoog medium supplemented with 5.0-mg/L 6-benzylaminopurine and 0.1-mg/L 1-naphthaleneacetic acid. On an average, five shoots per explant were formed, and of them, one shoot managed to form the root and developed into a whole plant. Conclusions: We obtained an optimized protocol for the biolistic transformation of chili and in vitro regeneration of chili plantlets. The establishment of the protocols will provide a platform for molecular breeding and biological studies of chili plants.

Particle gun-mediated bone morphogenetic protein-2 gene transfection for treatment of chronic bone defects / 中国组织工程研究

BACKGROUND:Both in vitro and in vivo studies have confirmed that, bone morphogenetic protein (BMP) regulates the differentiation of osteoblasts and chondroblasts, induces heterotopic bone formation, promotes fracture healing, and controls the morphology of skeleton in mammals. OBJECTIVE:To treat chronic bone defects using particle gun containing BMP2 gene eukaryotic expression plasmid via local injection. METHODS:A total of 72 healthy New Zealand white rabbits were applied to establish chronic bone defect model in the rabbit radius. According to the length of bone defect, the rabbits were divided into three groups:1.5 cm group, 2.0 cm group, 2.5 cm group. Each group was further randomly assigned into two subgroups:treatment group (BMP-2 gene transfection) and control group (natural y healing). X-ray examinations were performed at 1, 3, 8 and 9 weeks after transfection, and soft tissue between the bone defects was harvested to detect BMP-2 using western blot analysis;and radius specimens were taken for gross observation at the same time points, to evaluate the healing. RESULTS AND CONCLUSION:(1) Gross specimen observation:bone cal us formation in treatment group was general y more than that in control group. (2) Lane-Sandhu X-ray score in treatment group was significantly higher than that in control group at 1, 3, 8, 9 weeks after transfection (P<0.05). (3) BMP-2 concentration in treatment group was significantly higher than that in control group at each time point (P<0.05). The local transfer of particle gun-mediated BMP-2 gene is an effective therapy of chronic bone defect.

Transgene elimination in genetically modified dry bean and soybean lines

Transgene elimination is a poorly studied phenomenon in plants. We made genetic and molecular studies of a transgenic dry bean line immune to bean golden mosaic geminivirus and a soybean line. In both lines, the transgenes were stable during the vegetative phase but were eliminated during meiosis. Due to its potential biotechnological value, this transgenic line was micropropagated by grafting and the vegetative copies were studied for more than two years. More than 300 plants of progeny were obtained during this period, demonstrating that the phenomenon of elimination was consistently repeated and offering an opportunity for detailed study of transgene elimination, including the characterization of the integration sites. Cloning and sequencing of the transgenic loci, reciprocal crosses to untransformed plants, genomic DNA blots, and GUS assays were performed in the transgenic lines. Based on the molecular and genetic characterization, possible mechanisms involved in transgene elimination include intrachromosomal recombination, genetic instability resulting from the tissue culture manipulations, and co-elimination of transgenes, triggered by a process of genome defense.

Un método de transformación genética de maíz para conferirle resistencia ulterior a enfermedades virales / A method for genetic transformation of maize for resistance to viral diseases

A system for the genetic transformation of maize was developed for two Costa Rican varieties: CR-7 and Diamantes 8843, that can allow the subsequent transfer of viral-derived genes in order to confer resistance to the disease caused by maize rayado fino virus (MRFV). The method is based on particle bombardment of organogenic calli derived from shoot tips. On the other hand, the molecular construction pRFcp-bar, containing the coat protein gene of MRFV and the marker gene bar, was elaborated. For the visual selection of the transformed material was used also the plasmid pDM803 that contains the reporter gene uidA (GUS). The results indicate that devices evaluated: the PIG ("Particle Inflow Gun") and the Bio-Rad are both enough efficient to transfer foreign genes to the genome of the maize.

Expression of particle gun-transfected IgHV1-GM-CSF gene in dendritic cells / 解放军医学杂志

Objective To explore the application of particle-gun technique in transfecting dendritic cells(DCs),and investigate the expression of DNA vaccine particle IgHV1-GM-CSF in DCs induced by particle-gun.Methods Monocytes were isolated from donor peripheral blood collected by Ficoll density gradient method and adherent culture,and then differentiated into immature DCs(imDCs) by rhGM-CSF and rhlL-4 induction.The plasmids for transfection were IgHV1-GM-CSF/pcDNA3.0 and pEGFP,which were prepared with endofree plasmid purification kit.The DCs were transfected with plasmid pEGFP by particle-gun at different transfection conditions,the green fluorescence positive cell and the total cell numbers were counted respectively under fluorescence microscope,and the transfection efficiency was calculated;the viable cell count was performed after trypan blue staining;the transfection efficiencies of particle-gun,liposome-mediated transfection and electroporation method were compared.The plasmids IgHV1-GM-CSF/pcDNA3.0 and pEGFP were cotransfected into imDCs by particle-gun under the optimum conditions,and then DNA was extracted,the expression of IgHV1-GM-CSF was determined by RT-PCR,and of GM-CSF by ELISA.Results The optimum conditions of particle-gun transfection in imDCs were: gas pressure at 120psi,PVP concentration in 0.02mg/ml,microcarrier loading in 0.5mg gold/shot,and DNA loading ratio in 1.5?g plasmid/mg gold.The transfection efficiencies of particle-gun and electroporation were 10.5%?2.4%(n=3) and 45.2%?5.6%(n=3) respectively,while that of liposome-mediated transfection was very low,and significant difference existed among the three methods(P