Improving in vitro screening compounds anti-Trypanosoma cruzi by GFP-expressing parasites

BACKGROUND Conventional microscopic counting is a widely utilised method for evaluating the trypanocidal effects of drugs on intracellular amastigotes. This is a low-cost approach, but it is time-consuming and reliant on the expertise of the microscopist. So, there is a pressing need for developing technologies to enhance the efficiency of low-cost anti-Trypanosoma cruzi drug screening. OBJECTIVES In our laboratory, we aimed to expedite the screening of anti-T. cruzi drugs by implementing a fluorescent method that correlates emitted fluorescence from green fluorescent protein (GFP)-expressing T. cruzi (Tc-GFP) with cellular viability. METHODS Epimastigotes (Y strain) were transfected with the pROCKGFPNeo plasmid, resulting in robust and sustained GFP expression across epimastigotes, trypomastigotes, and intracellular amastigotes. Tc-GFP epimastigotes and intracellular amastigotes were exposed to a serial dilution of benznidazole (Bz). Cell viability was assessed through a combination of microscopic counting, MTT, and fluorimetry. FINDINGS The fluorescence data indicated an underestimation of the activity of Bz against epimastigotes (IC50 75 µM x 14 µM). Conversely, for intracellular GFP-amastigotes, both fluorimetry and microscopy yielded identical IC50 values. Factors influencing the fluorimetry approach are discussed. MAIN CONCLUSIONS Our proposed fluorometric assessment is effective and can serve as a viable substitute for the time-consuming microscopic counting of intracellular amastigotes.

Establishment of mouse models of lymphoma with dual-labeled EBV-immortalized lymphoblastoid cell lines by intravenous versus subcutaneous injection / 中国肿瘤临床

Objective:To establish a green fluorescent protein(GFP)and firefly luciferase(Luc)double-labeled Epstein-Barr virus(EBV)infec-ted B lymphoblastoid cell lines(B-LCL)and apply them to mouse models,then compare the advantages and disadvantages of models inocu-lated by intravenous(IV)or subcutaneous(SC).Methods:B lymphoblastoid cell lines double-tagged with GFP/Luc(B-LCL-GL)were con-structed through lentivirus transduction,puromycin intervention.Subcutaneous xenograft and hematogenous metastasis models were re-spectively established by subcutaneous or intravenous injection of B-LCL-GL cells at three concentrations in(NOD)/Prkdcscid/IL-2Rγnull(NPG)mice for in vivo bioluminescence imaging.Results:In the B-LCL-GL group,the ratio of the GFP-positive cell population was 92.5%,and the average luminescence intensity was as high as 4.80E+08 Photons/s,which was considerably higher than that of untreated B-LCLs.In the hematogenous metastasis models,tumor bioluminescence was initially located in the peritoneal area and then spread throughout the en-tire body between 7 and 28 days.In the subcutaneous xenograft models,strong central and weak peripheral tumor-related biolumines-cence signal was detected on day 7 in the three groups,which then spread throughout the body on day 28 in the high-dose group.Taken to-gether,there was no significant difference in tumor progression between the two routes of administration when using the same dose of B-LCL-GL cells.However,the survival analysis indicated that the IV injection group,in which all the mice ultimately died,had a shorter time frame for testing than that of the SC injection group,in which the mice survived until day 100 in the low-dose and medium-dose groups,thus allowing for long-term testing.Conclusions:GFP and Luc dual-positive B-LCLs were successfully established to generate hematogenous metastasis and subcutaneous xenograft models,which allow the monitoring of the location and size of lymphomas in vivo.It provide plat-form for the study of tumor characteristics and selecting anti-tumor drugs.

Preparation and characterization of Ad-ERα-36-Fc-GFP / 生物工程学报

ERα-36 is a novel subtype of estrogen receptor α which promotes tumor cell proliferation, invasion and drug resistance, and it serves as a therapeutic target. However, only small-molecule compounds targeting ERα-36 are under development as anticancer drugs at present. Gene therapy approach targeting ERα-36 can be explored using recombinant adenovirus armed with decoy receptor. The recombinant shuttle plasmid pDC316-Ig κ-ERα-36-Fc-GFP was constructed via genetic engineering to express an Ig κ-signaling peptide-leading secretory recombinant fusion protein ERα-36-Fc. The recombinant adenovirus Ad-ERα-36-Fc-GFP was subsequently packaged, characterized and amplified using AdMaxTM adenovirus packaging system. The expression of fusion protein and functional outcome of Ad-ERα-36-Fc-GFP transduction were further analyzed with triple-negative breast cancer MDA-MB-231 cells. Results showed that the recombinant adenovirus Ad-ERα-36-Fc-GFP was successfully generated. The virus effectively infected MDA-MB-231 cells which resulted in expression and secretion of the recombinant fusion protein ERα-36-Fc, leading to significant inhibition of EGFR/ERK signaling pathway. Preparation of the recombinant adenovirus Ad-ERα-36-Fc-GFP provides a basis for further investigation on cancer gene therapy targeting ERα-36.

Quality changes of Gardeniae Fructus Praeparatus processed by different frying methods: a color-component correlation analysis / 中国中药杂志

The chromatic values of the broken-fried and single-fried Gardeniae Fructus Praeparatus(GFP) were measured by the color analyzer to analyze the color variation rule, and the contents of 10 main components were determined by ultra-high performance liquid chromatography(UPLC). The multivariate statistical analysis, Pearson correlation analysis, and discriminant analysis were conducted to investigate the color and components of GFP samples. The experimental results revealed that L~*, a~*, b~*, and E~*ab decreased continuously during processing, and the color of samples gradually deepened. The trend and range of chromatic values during broken-frying and single-frying processes were basically identical. Gardenoside, crocin-Ⅰ(C-Ⅰ), and crocin-Ⅱ(C-Ⅱ) showed an obviously downward trend, while the contents of geniposidic acid and 5-hydroxymethylfurfural(5-HMF) increased significantly. Shanzhiside, deacetyl-asperulosidic acid methyl ester, and geniposide(G2) showed a downward trend. Scandoside methyl ester rose first and fell later. Genipin-1-O-gentiobioside(G1) went through a decrease-increase-decrease trend. The change trends of component contents during broken-frying and single-frying processes were generally consistent, but the change range was different. Among all the components, scandoside methyl ester and G1 showed obvious change. Because of different stir-frying time, the change rate of each component content in the process of broken-frying was higher than that in single-frying process. Additionally, geniposidic acid, gardenoside, scandoside methyl ester, C-Ⅰ, C-Ⅱ, and 5-HMF exhibited a higher correlation with apparent color. On the basis of above findings, the discriminant function of two frying processes was established, which could be applied to the discrimination of broken-fried and single-fried samples. This study analyzed the dynamic quality change rule of GFP during broken-frying and single-frying processes based on color-component correlation analysis, and found the two methods showed consistent change trend, yet with slight difference in the quality of samples. This study can provide data support for the processing of GFP.

Targeting peptide-decorated biomimetic lipoproteins improve deep penetration and cancer cells accessibility in solid tumor

The limited penetration of nanoparticles and their poor accessibility to cancer cell fractions in tumor remain essential challenges for effective anticancer therapy. Herein, we designed a targeting peptide-decorated biomimetic lipoprotein (termed as BL-RD) to enable their deep penetration and efficient accessibility to cancer cell fractions in a tumor, thereby improving the combinational chemo-photodynamic therapy of triple negative breast cancer. BL-RD was composed of phospholipids, apolipoprotein A1 mimetic peptide (PK22), targeting peptide-conjugated cytotoxic mertansine (RM) and photodynamic agents of DiIC18(5) (DiD). The counterpart biomimetic lipoprotein system without RM (termed as BL-D) was fabricated as control. Both BL-D and BL-RD were nanometer-sized particles with a mean diameter of less than 30 nm and could be efficiently internalized by cancer cells. After intravenous injection, they can be specifically accumulated at tumor sites. When comparing to the counterpart BL-D, BL-RD displayed superior capability to permeate across the tumor mass, extravasate from tumor vasculature to distant regions and efficiently access the cancer cell fractions in a solid tumor, thus producing noticeable depression of the tumor growth. Taken together, BL-RD can be a promising delivery nanoplatform with prominent tumor-penetrating and cancer cells-accessing capability for effective tumor therapy.

Generation and evaluation of a recombinant myxomavirus expressing the VP60 protein of rabbit haemorrhagic disease virus / 生物工程学报

Rabbit haemorrhagic disease virus (RHDV) and myxoma virus (MYXV), are two pathogens that have harmful effect on rabbit breeding and population decline of European rabbits in their native range, causing rabbit haemorrhagic disease (rabbit fever) and myxomatosis, respectively. The capsid protein VP60 of the RHDV represents the major antigenic protein. To develop a recombinant bivalent vaccine candidate that can simultaneously prevent these two diseases, we used the nonessential gene TK (thymidine kinase) of MYXV as the insertion site to construct a recombinant shuttle vector p7.5-VP60-GFP expressing the RHDV major capsid protein (VP60) and the selectable marker GFP. Then the shuttle vector p7.5-VP60-GFP was transfected into rabbit kidney cell line RK13 which was previously infected with MYXV. After homologous recombination, the recombinant virus expressing GFP was screened under a fluorescence microscope and named as rMV-VP60-GFP. Finally, the specific gene-knock in and expression verification of the vp60 and gfp genes of the recombinant virus was confirmed by PCR and Western blotting. The results showed that these two genes were readily knocked into the MYXV genome and also successfully expressed, indicating that the recombinant MYXV expressing the vp60 of RHDV was generated. Protection against MYXV challenge showed that the recombinant virus induced detectable antibodies against MYXV which would shed light on development of the effective vaccine.

Characterisation of alternative expression vectors for recombinant Bacillus Calmette-Guérin as live bacterial delivery systems

BACKGROUND Bacillus Calmette-Guérin (BCG) is considered a promising live bacterial delivery system. However, several proposals for rBCG vaccines have not progressed, mainly due to the limitations of the available expression systems. OBJECTIVES To obtain a set of mycobacterial vectors using a range of promoters with different strengths based on a standard backbone, previously shown to be stable. METHODS Mycobacterial expression vectors based on the pLA71 vector as backbone, were obtained inserting different promoters (PAN, PαAg, PHsp60, PBlaF* and PL5) and the green fluorescence protein (GFP) as reporter gene, to evaluate features such as their relative strengths, and the in vitro (inside macrophages) and in vivo stability. FINDINGS The relative fluorescence observed with the different vectors showed increasing strength of the promoters: PAN was the weakest in both Mycobacterium smegmatis and BCG and PBlaF* was higher than PHsp60 in BCG. The relative fluorescence observed in a macrophage cell line showed that PBlaF* and PHsp60 were comparable. It was not possible to obtain strains transformed with the extrachromosomal expression vector containing the PL5 in either species. MAIN CONCLUSION We have obtained a set of potentially stable mycobacterial vectors with a arrange of expression levels, to be used in the development of rBCG vaccines.

Fluorescence tracing of umbilical cord blood mesenchymal stem cells in transplantation treatment of scalded wound in mice / 国际检验医学杂志

Objective Using the previously established mesenchymal stem cells strain derived from human fetal umbilical cord blood (FUCB-MSCs) to culture then label enhanced green fluorescent protein (EGFP) , and to observe skin repair effects of FUCB-MSCs by GFP tracing after exogenous FUCB-MSCs transplantation on to scald wound models of SCID mice.Methods FUCB-MSCs were labeled GFP by transfection with the recombinant retrovirus containing EGFP gen;The established SCID scald mice model were randomLy divided into 3groups, low dose group, high dose group and control group, 6rats each group, 2wounds each mouse, 12wounds in total, then were tail intravenous injected into 0.2mL 1×106, 0.2mL 2×106 GFP-FUCB-MSCs cells, and same volume of medium respectively.On 9days after transplantation, the sections from scald wound area were observed the expression of GFP under the fluorescence microscope and the others were analyzed by the bright-field microscopy after HE staining, and the area of wound surface and the number of wound cells were compared simultaneously.Results After 48h, expression of EGFP in FUCB-MSCs can be seen under the fluorescence microscope, positive rate of GFP was>80％, and after 6weeks GFP expression is still stable, besides, the positive expression of human GFP can be observed after transplantation and there were no fluorescence decay in transplantation after 3weeks.Compared with the control group, there was a significant difference in wound area and wound cell number in the low and high-dose group (P<0.05) .ConclusionGFP can be used as a tracking marker to label FUCB-MSCs during transplantation treatment.It indicates that exogenous FUCB-MSCs can migrate to the scalded wounds via blood circulation system and continuously participate in the repair through SCID mouse.

Melanoma transplants in "green" mice: Fluorescent cells in tumors are not equivalent to host-derived cells

Background: To examine the usefulness of green fluorescent protein (GFP) mice for studying the interactions between normal cells and tumor cells in a host, we used a melanoma model in such "green" mice [C57BL/6-Tg (CAG-EGFP)1Osb mice]. Mice were given a subcutaneous injection of B16-F10 cells, and the resultant primary tumors were removed. Then cells from individual tumors were cultured. Results: The proportion of EFGP+ cells was determined by fluorescence-activated cell sorting (FACS) and was 6.8% ± 3.2% (mean ± s.d.) on day 1 of culture, 0.6% ± 0.3% on day 2, and 0.02% ± 0.01% at day 7. In all cases, isolated cells grew at a constant rate, but fluorescence decreased over time and became undetectable on day 14. Cells were tested using PCR for the presence of an EGFP-specific sequence, and results were negative in all cases, thus indicating that the cells did not harbor the host's reporter gene. Cells were also tested for the presence of EGFP mRNA, which was consistently detected for 22 days after the start of culture. The tumorogenicity of the cultured cells was confirmed in GFP mice injected with cells from a selection of cultures. Conclusions: In a melanoma model in GFP mice, the detection of "green" cells in tumors was not equivalent to the detection of host-derived cells. Such "masking" was caused by a transient, but lasting, transfer of EGFP mRNA from the host's normal cells to tumor cells. Thus, an analysis of tumors postmortem by techniques that yield only a single snapshot can lead to incorrect interpretations and erroneous conclusions.

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.

Study on Inhibitory Effects of Recombinant Adenovirus Ad-GFP-C197 on 3 Kinds of Tumor Cells / 中国药房

OBJECTIVE:To study the inhibitory effects of recombinant adenovirus Ad-GFP-C197, which prepared by adenovirus vector system-loading human telomerase reverse transcriptase(hTERT)C fragment(C197),on the proliferation of 3 kinds of tumor cells in vitro. METHODS:Ad-GFP-C197 was amplified and purified with HEK293 cells. Human gastric cancer cells SGC7901,human breast cancer cells MCF7 and human colorectal cancer cells CaCO2 were infected by Ad-GFP-C197 respectively. Using blank adenovirus carrier (Ad-GFP) as reference,the protein expression of C197 in 3 kinds of tumor cells infected by Ad-GFP-C197 was detected by Western blot assay. The inhibitory effects of Ad-GFP-C197 on 3 kinds of tumor cells were detected by MTT assay. The cell proliferation curve was drawn and the proliferation inhibition rate was calculated. RESULTS:The protein expression of C197 was not detected in 3 kinds of tumor cells infected by Ad-GFP,while significant protein expression of C197 was found in above cells infected by Ad-GFP-C197. The proliferation curves of the 3 kinds of tumor cells infected by Ad-GFP-C197 were significantly inhibited with the time extended,and the proliferation inhibitory rate reached 37.31%-41.42%. CONCLUSIONS:Ad-GFP-C197 shows significant inhibitory effects on the proliferation of SGC7901,MCF7 and CaCO2 cells, which is rapid to make up for the slow effect of other telomerase inhibitors.

Establishment of a genetic transformation system for hairy root culture of Erigeron breviscapus / 中国中药杂志

The electroporation method was performed to transfer plasmid DNA of PBI-1300 carrying GFP gene into Agrobacterium rhizogenes C₅₈C₁ strains. Mediated by A. rhizogenes C₅₈C₁, the GFP gene were transformed into Erigeron breviscapus aseptic leaves by leaf disc method, then the hairy roots were induced and the infected hairy roots were screened by hygromycin resistance. The chromosomal DNA of the hairy root was used as the templates for the PCR amplification with the GFP-specific primers and then the expected amplified DNA bands appeared, the green fluorescent of GFP in the cut hairy roots was observed by two-photon microscope. These results indicated that GFP gene was integrated into the genome of E. breviscapus and was expressed stably. This study laid the groundwork for foreign gene high-efficiency expression inthe genetic transformation system for hairy root culture of E. breviscapus.

Single-cell qPCR facilitates the optimization of hematopoietic differentiation in hPSCs/OP9 coculture system

Human pluripotent stem cells (hPSCs)/OP9 coculture system is a widely used hematopoietic differentiation approach. The limited understanding of this process leads to its low efficiency. Thus, we used single-cell qPCR to reveal the gene expression profiles of individual CD34+ cells from different stages of differentiation. According to the dynamic gene expression of hematopoietic transcription factors, we overexpressed specific hematopoietic transcription factors (Gata2, Lmo2, Etv2, ERG, and SCL) at an early stage of hematopoietic differentiation. After overexpression, we generated more CD34+ cells with normal expression level of CD43 and CD31, which are used to define various hematopoietic progenitors. Furthermore, these CD34+ cells possessed normal differentiation potency in colony-forming unit assays and normal gene expression profiles. In this study, we demonstrated that single-cell qPCR can provide guidance for optimization of hematopoietic differentiation and transient overexpression of selected hematopoietic transcription factors can enhance hematopoietic differentiation.

Construction of pMSV-Slfn5-GFP plasmid and analysis of gene structure in mice / 重庆医学

Objective To perform mouse pMSV-Slfn5-GFP gene recombinant expression plasmid construction and gene structure analysis.Methods Total RNA was extracted from mouse liver and turned into cDNA by reverse transcription.Mouse Slfn5 coding sequence (CDS) fragment was amplified by PCR and connected with the pGEM-T Easy vector.The connected product was transferred the E.coli DH5a.The positive clones were selected for extracting plasmid,which was identified by double enzyme of restriction endonuclease Hpa Ⅰ and Xho Ⅰ.Then correct plasmid identified by enzyme digestion was sequenced by Macrogen USA.Then correct plasmid by sequencing was connected with pMSV-GFP by HindⅢ and Xbo Ⅰ,which was named as pMSV-Slfn5-GF.UCSC (http://genome.ucsc.Edu/) was used to analyze mouse Slfn5 and its family genomic structure.Slfn5 protein structural domain was determined by NCBI.Results Slfn5 full-length gene sequence was cloned into the expression vector pMSV-GFP,the fragment size was about 2.65 kb by enzyme digestion identification.The conservatism of AAA_4 protein domain in Slfn5 protein family was determined by phylogeny.fr.Conclusion Mouse full-length gene pMSV-Slfn5-GFP expression vector is successfully constructed.

Neurodegenerative disorder after optic nerve crush in transgenic fluorescence mice / 眼科新进展

Objective To observe optic nerve axons degenerative disorder and microglial responses by establishing unilateral optic nerve crush model.Methods YFP mouse group with axonal markers and GFP mouse group with microglia markers were divided into surgery and control group,the optic nerve were dissected at 4 hours,1 day,3 days,5 days,10 days after optic nerve crush,and the neuronal degenerative disorder and microglial responses were observed by confocal laser scanning microscope.Rrsults Compared with control group,the optic nerve axons in YFP mouse group were fractured in injury region at postoperative 4 hours;The partial axon became beadlike change at postoperative 1 day;Most of the axons turned into the process of beadlike change at postoperative 3 days;The axons became to debris from beadlike at postoperative 5 days;The axons changed into many debris at postoperative 10 days.Compared with control group,the formation of glial scar and resting microglia in GFP mouse group began to emerge at postoperative 4 hours;The microglia gradually activated and began to cover the injury region at postoperative 1 day;The activated miacroglia basically covered the injury region at postoperative 3 days;The number of microglia roughly remained stable,although the axons continued to deteriorate at postoperative 5 days and 10 days.Conclusion The optic nerve occur irreversible degenerative disorder after being injured,meanwhile with the microglial increase and activation.This phenomenon suggests that microglia is closely associated with optic nerve degeneration.

Nuevo método de evaluación del efecto antiparasitario en modelos in vitro e in vivo, a través de la visualización de Trypanosoma cruzi-GFP / New method of evaluation of the antiparasitic effect models in in vitro and in vivo, through the viewing of Trypanosoma cruzi-GFP

Los tratamientos de primera línea para la enfermedad de Chagas generan importantes efectos adversos que acentúan el deterioro de la salud en los pacientes. La necesidad de generar fármacos alternativos ha permitido desarrollar estudios donde se emplean parásitos capaces de expresar una proteína fluorescente, a fin de correlacionar fluorescencia con población de protozoarios. En este sentido, ideamos una metodología para el seguimiento de la proliferación de Trypanosoma cruzi-GFP (Green Fluorescent Protein) en modelos in vitro e in vivo, empleando el equipo iBox- UVP. Los ensayos in vitro se iniciaron con una curva de calibración usando concentraciones entre 5x105 y 5x107 parásitos/mL. Seguidamente, con una curva de proliferación evidenciamos a través de la fluorescencia la susceptibilidad de los parásitos frente a la droga comercial Benznidazol (IC50= 5,3±1,3 μM). En el ensayo in vivo se corroboró cualitativamente el efecto quimioterapéutico del Benznidazol (100 mg/kg/día) en ratones C57BL/6, partiendo de un inóculo de 2,5x105 parásitos, haciendo captura de imágenes de fluorescencia cada dos días a partir del día 1, e inicio del tratamiento por vía oral el sexto día. El coeficiente de correlación cercano a 1 obtenido en la curva de calibración habla de un método de cuantificación parasitario sencillo y robusto; también los ensayos en modelos in vitro e in vivo permitieron monitorear el efecto dosis-dependiente de Benznidazol sobre T. cruzi-GFP. En síntesis, elaboramos una metodología novedosa, rápida, no invasiva y que sigue en tiempo real la respuesta quimioterapéutica de drogas anti-T. cruzi.

The first-line treatments for Chagas disease generate significant adverse effects that accentuate the health deterioration in patients. The need to generate alternative drugs has led to the development of studies in which parasites will express a fluorescent protein, and correlate this expression with protozoan population. We devised a methodology for monitoring the proliferation of Trypanosoma cruzi- GFP (Green Fluorescent Protein) in models in vitro and in vivo, using the equipment iBox-UVP. In vitro assays were initiated with a calibration curve using concentrations between 5x105 and 5x107 parasites/mL. Subsequently, with a proliferation curve, through fluorescence we determined the susceptibility of the parasites against the commercial drug Benznidazol (IC50= 5,3±1,3 μM). In vivo assays corroborated qualitatively the chemotherapeutic effect of Benznidazol (100 mg/kg/day) in C57BL/6 mice, starting from an inoculum of 2.5x105 parasites, making capture of fluorescence imaging every two days from day 1, and starting oral treatment on the sixth day. The correlation coefficient close to 1 obtained in the calibration curve showed that this quantification method of parasites is simple and robust; assays in vitro and in vivo allowed monitoring dose-dependent effects of Benznidazol agains T. cruzi-GFP. We have produced an innovative, rapid, non-invasive method that monitors in real time the chemotherapeutic response of anti-T. cruzi drugs.

In situ real-time evaluation of radiation-responsive promoters in the extremely radioresistant microbe Deinococcus radiodurans.

A third generation promoter probe shuttle vector pKG was constructed, using the green fluorescent protein as a reporter, for in situ evaluation of Deinococcal promoter activity in Escherichia coli or Deinococcus radiodurans. The construct yielded zero background fluorescence in both the organisms, in the absence of promoter sequences. Fifteen Deinococcal promoters, either harbouring Radiation and Desiccation Response Motif (RDRM) or not, were cloned in vector pKG. Only the RDRM-promoter constructs displayed (i) gamma radiation inducible GFP expression in D. radiodurans, following gamma irradiation, (ii) DdrO-mediated repression of GFP expression in heterologous E. coli, or (iii) abolition in GFP induction following gamma irradiation, in pprI mutant of D. radiodurans. Utility of pKG vector for real-time in situ assessment of Deinococcal promoter function was, thus, successfully demonstrated.

Repairing effect of embryonic stem cells on injured maternal myocardium in pregnant mice / 中国实验动物学报

Objective To determine if fetal stem cells can enter the maternal circulation during pregnancy and re-pair the injuries of maternal heart.Methods C57 female mice at the age of 6-8 weeks were randomly assigned to three groups:sham control, surgery without pregnancy, and surgery with pregnancy ( n=8,eath group) .The control sham group was developed by opening and closing of the chest.The other two groups underwent heart surgery.The myocardial infarc-tion ( MI) model was induced by ligation of the left anterior descending coronary artery.Half of the surgical mice mated with e-GFP transgenic male mice, and another half group was not.Electrocardiogram ( ECG) and echocardiographic images were recorded at pre-operation, post-operation and postpartum.The collected data were used to evaluate the heart function. The GFP expression was detected by immunohistochemistry and q-PCR.Results When compared with the sham group, both the ischemia surgery groups with and without pregnancy, the ECG ST segment was significantly increased.This meas-urement indicated that the myocardial ischemia surgery was successful, and no significant difference in the ST segments be-tween two ischemia surgery groups was found.However, when ECG was measured in the surgical mice after postpartum, their myocardial ischemia was dramatically improved when compared with that of the ischemia surgery only mice.Echocar-diographic images also indicated that both the surgery groups had myocardial ischemia, however, no significant difference was observed in the pregnant mice before and after postpartum.The order of the cardiac function indexes from high to low was the sham group, surgery with pregnancy group, and surgery with no pregnancy group;in particular, the cardiac func-tion of pregnancy group was significantly enhanced compared with that of the surgery with no pregnancy group (P<0.05). More importantly, both immunofluorescence and q-PCR results showed that the embryonic stem cell translocation through circulation system with GFP expression in the heart of pregnancy group, while negative in other two groups.Conclusions Embryonic stem cells can be transferred into the maternal circulation of pregnant mice, and play a role in the repairing of their cardiac injuries.

Effect of down-regulation of dihydrofolate reductase on biological function of ovarian cancer cellsin vitro / 中国癌症杂志

Background and purpose:Dihydrofolate reductase (DHFR) is expressed highly in platinum-resis-tant ovarian cancer. This study aimed to explore the relationship between the silence ofDHFR gene and platinum drug resistance in ovarian cancer, and lay the foundation for the treatment of platinum-resistant ovarian cancer.Methods:To design targeting hairpin siRNA ofDHFR gene, the optimal siRNA silent sequence was selected, and lentiviral vector carryingDHFR gene was constructed successfully, named DHFR-pGCSIL-SKOV3 cell. Flow cytometry was used to detect the cell apoptosis of DHFR-pGCSIL-SKOV3 cells, pGCSIL-SKOV3 cells and SKOV3 cells incubated in various concentrations of cisplatin (2.5, 5.0, 10.0 and 20.0 μg/mL) at different time points (24, 48 and 72 h), and cell cycle changes of these cells at IC50 cisplatin concentration (4.4 μg/mL). High performance liquid chromatography was used to test intracellular concentration of cisplatin at different induction concentration of cisplatin (2.5, 5.0 and 7.5 μg/mL) and various time points (24 and 48 h). Ultrastructural changes of these cells at concentration of cisplatin IC50 (4.4 μg/mL) were observed by transmission electron microscope.Results:After annealing double-strand nucleotide was connected to pGCSIL/GFP vector, sequencing result was correct. SKOV3 cell were transfected with virus particles followed by Western blot detection of interference effect. Flow cytometry was used to detect apoptosis in three groups of cells, and increased apoptosis rate was found at the raised cisplatin concentration (2.5, 5.0, 10.0 and 20.0 μg/mL) at 24, 48 and 72 h in DHFR-pGCSIL-SKOV3, pGCSIL-SKOV3 and SKOV3 cells. The apoptosis rate in DHFR-pGCSIL-SKOV3 was signiifcantly higher than that in pGCSIL-SKOV3 and SKOV3 cells at 24 and 48 h (P<0.05). Flow cytometry was adopted to test cells cycle of 3 groups at different time period under IC50 cisplatin concentration (4.4 μg/mL), the results indicated that G0/G1 phase cell rate of DHFR-pGCSIL-SKOV3 was much more than the others, of which G2/M and S phase cell rates were on the contrary. While at 72 h, 3 groups were mainly G2/M and S phase cell rates, DHFR-pGC-SIL-SKOV3 was lower than the others. High performance liquid chromatography method was used to detect intracellu-lar cisplatin concentration at 24 and 48 h after the cells were incubated at various concentrations of cisplatin (2.5 and 5.0μg/mL). The results showed the intracellular cisplatin content of DHFR-pGCSIL-SKOV3 cell was signiifcantly higher than that of pGCSIL-SKOV3 and SKOV3 cells. However, after incubation at cisplatin concentration of 7.5 μg/mL, the intracellular cisplatin content of DHFR-pGCSIL-SKOV3 cell was signiifcantly lower than that of pGCSIL-SKOV3 and SKOV3 cells at 24 h, while higher than pGCSIL-SKOV3 and SKOV3 cells at 48 h (P=0.034,P=0.014). We observed ultrastructural changes of three different cell lines induced by IC50 cisplatin concentration(4.4 μg/mL) at different time points by the electron microscope. We found that the microiflaments were increased and gathered together and mitochondrial structure was also changed obviously without the drug. However, there was rare microiflament in three groups of cells at 24 and 48 h, while at 72 h, obviously increased inordinate microiflaments were observed.Conclusion:We successfully constructed pGCSIL lentivirus interference carrier carryingDHFR gene. The research indicates that down-regulation ofDHFR gene is related to cisplatin drug resistance in ovarian cancer. The results laid the foundation for us to investigate the molecular mechanisms of multidrug-resistance in tumor.

Effects of Recombinant Adenovirus Carrying Apoptin Gene on the Apoptosis of Human Lung Squamous Carcinoma SK-MES-1 Cell Lines and Human Lung Adenocarcinoma NCI-H1299 Cell Lines / 中国药房

OBJECTIVE:To explore the effects of recombinant adenovirus vector Adxsi-GFP-VP3 carrying apoptin gene VP3 on the apoptosis of human lung squamous carcinoma SK-MES-1 cell lines and human lung adenocarcinoma NCI-H1299 cell lines. METHODS:The exponential phase SK-MES-1 and NCI-H1299 cell lines were respectively divided into a recombinant adenovirus (Adxsi-GFP-VP3) group,a empty virus (Adxsi-GFP) group and a cell control (phosphate buffer) group,which were marked as group A,B and C respectively. Reverse transcription polymerase chain reaction and Western blot method were used to detect the ex-pressions of VP3 mRNA and Apoptin in the cells of groups A and B 48 and 72 h after transfection. The change in the ultrastructure of the cells in group A was observed under transmission electron microscope 72 h thereafter. MTT method was adopted to detect the cell proliferation activities of three groups 24,48,72 and 96 h thereafter and flow cytometry to determine the apoptosis rates and cell cycle changes 24,48 and 72 h thereafter. RESULTS:Compared to group B,group A demonstrated the expression of VP3 mRNA in SK-MES-1 and NCI-H1299 cell lines 48 h after transfection,and Apoptin expression and ultrastructure change for apopto-sis of SK-MES-1 and NCI-H1299 cell lines 72 h thereafter. Compared to groups B and C,group A showed lower proliferation activ-ities and higher apoptosis rates of SK-MES-1 and NCI-H1299 cell lines,which had a positive correlation with transfection time;and in the group A,there was a decrease in the proportion of the SK-MES-1 and NCI-H1299 cell lines in S phase and an increase in the proportion of those in G2/M phase,72 h after transfection. There was statistically difference (P<0.05). CONCLUSIONS:Adxsi-GFP-VP3 can effectively induce the apoptosis of SK-MES-1 and NCI-H1299 cell lines.