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Fulltext Agrobacterium-mediated transformation of the recalcitrant Vanda Kasem's Delight orchid with higher efficiency

Gnasekaran P, Antony JJ, Uddain J, Subramaniam S

ScientificWorldJournal, 2014;2014:583934.
PMID: 24977213 DOI: 10.1155/2014/583934

The presented study established Agrobacterium-mediated genetic transformation using protocorm-like bodies (PLBs) for the production of transgenic Vanda Kasem's Delight Tom Boykin (VKD) orchid. Several parameters such as PLB size, immersion period, level of wounding, Agrobacterium density, cocultivation period, and concentration of acetosyringone were tested and quantified using gusA gene expression to optimize the efficiency of Agrobacterium-mediated genetic transformation of VKD's PLBs. Based on the results, 3-4 mm PLBs wounded by scalpel and immersed for 30 minutes in Agrobacterium suspension of 0.8 unit at A 600 nm produced the highest GUS expression. Furthermore, cocultivating infected PLBs for 4 days in the dark on Vacin and Went cocultivation medium containing 200 μM acetosyringone enhanced the GUS expression. PCR analysis of the putative transformants selected in the presence of 250 mg/L cefotaxime and 30 mg/L geneticin proved the presence of wheatwin1, wheatwin2, and nptII genes.

Matched MeSH terms: Transfection/methods*
Fulltext Efficient transformation of oil palm protoplasts by PEG-mediated transfection and DNA microinjection

Masani MY, Noll GA, Parveez GK, Sambanthamurthi R, Prüfer D

PLoS One, 2014;9(5):e96831.
PMID: 24821306 DOI: 10.1371/journal.pone.0096831

Genetic engineering remains a major challenge in oil palm (Elaeis guineensis) because particle bombardment and Agrobacterium-mediated transformation are laborious and/or inefficient in this species, often producing chimeric plants and escapes. Protoplasts are beneficial as a starting material for genetic engineering because they are totipotent, and chimeras are avoided by regenerating transgenic plants from single cells. Novel approaches for the transformation of oil palm protoplasts could therefore offer a new and efficient strategy for the development of transgenic oil palm plants.

Matched MeSH terms: Transfection/methods
Escherichia coli bactofection using Lipofectamine

Narayanan K, Lee CW, Radu A, Sim EU

Anal Biochem, 2013 Aug 15;439(2):142-4.
PMID: 23608053 DOI: 10.1016/j.ab.2013.04.010

Successful gene delivery into mammalian cells using bactofection requires entry of the bacterial vector via cell surface integrin receptors followed by release of plasmid DNA into the cellular environment. We show, for the first time, that addition of the DNA transfection reagent Lipofectamine improves entry of invasive Escherichia coli into HeLa cells and enhances up to 2.8-fold green fluorescent protein (GFP) expression from a reporter plasmid. The addition of Lipofectamine may be applicable to other bacterial vectors to increase their DNA delivery efficiency into mammalian cells.

Matched MeSH terms: Transfection/methods*
Fluoride enhances transfection activity of carbonate apatite by increasing cytoplasmic stability of plasmid DNA

Chowdhury EH

Biochem Biophys Res Commun, 2011 Jun 17;409(4):745-7.
PMID: 21624351 DOI: 10.1016/j.bbrc.2011.05.079

Intracellular delivery of a functional gene or a nucleic acid sequence to specifically knockdown a harmful gene is a potential approach to precisely treat a critical human disease. The intensive efforts in the last few decades led to the development of a number of viral and non-viral synthetic vectors. However, an ideal delivery tool in terms of the safety and efficacy has yet to be established. Recently, we have developed pH-sensing inorganic nanocrystals of carbonate apatite for efficient and cell-targeted delivery of gene and gene-silencing RNA. Here we show that addition of very low level of fluoride to the particle-forming medium facilitates a robust increase in transgene expression following post-incubation of the particles with HeLa cells. Confocal microscopic observation and Southern blotting prove the cytoplasmic existence of plasmid DNA delivered by likely formed fluoridated carbonate apatite particles while degradation of plasmid DNA presumably by cytoplasmic nucleases was noticed following delivery with apatite particles alone. The beneficial role of fluoride in enhancing carbonate apatite-mediated gene expression might be due to the buffering potential of generated fluoridated apatite in endosomal acidic environment, thereby increasing the half-life of delivered plasmid DNA.

Matched MeSH terms: Transfection/methods*
Gene Silencing by RNAi in Mammalian Cells

Ponthan F, Yusoff NM, Soria NM, Heidenreich O, Coffey K

Curr Protoc Mol Biol, 2015 Jul 01;111:26.2.1-26.2.17.
PMID: 26131850 DOI: 10.1002/0471142727.mb2602s111

This unit provides information how to use short interfering RNA (siRNA) for sequence-specific gene silencing in mammalian cells. Several methods for siRNA generation and optimization, as well as recommendations for cell transfection and transduction, are presented.

Matched MeSH terms: Transfection/methods
Comparative characterization and cytotoxicity study of TAT-peptide as potential vectors for siRNA and Dicer-substrate siRNA

Katas H, Abdul Ghafoor Raja M, Ee LC

Drug Dev Ind Pharm, 2014 Nov;40(11):1443-50.
PMID: 23962166 DOI: 10.3109/03639045.2013.828222

Recently, a newly discovered Dicer-substrate siRNA (DsiRNA) demonstrates higher potency in gene silencing than siRNA but both suffer from rapid degradation, poor cellular uptake and chemical instability. Therefore, Tat-peptide was exploited to protect and facilitate their delivery into cells. In this study, Tat-peptide was complexed with siRNA or DsiRNA through simple complexation. The physicochemical properties (particle size, surface charge and morphology) of the complexes formed were then characterized. The ability of Tat-peptide to carry and protect siRNA or DsiRNA was determined by UV-Vis spectrophotometry and serum protection assay, respectively. Cytotoxicity effect of these complexes was assessed in V79 cell line. siRNA-Tat complexes had particle size ranged from 186 ± 17.8 to 375 ± 8.3 nm with surface charge ranged from -9.3 ± 1.0 to +13.5 ± 1.0 mV, depending on the Tat-to-siRNA concentration ratio. As for DsiRNA-Tat complexes, the particle size was smaller than the ones complexed with siRNA, ranging from 176 ± 8.6 to 458 ± 14.7 nm. Their surface charge was in the range of +27.1 ± 3.6 to +38.1 ± 0.9 mV. Both oligonucleotide (ON) species bound strongly to Tat-peptide, forming stable complexes with loading efficiency of more than 86%. These complexes were relatively non cytotoxic as the cell viability of ∼90% was achieved. In conclusion, Tat-peptide has a great potential as siRNA and DsiRNA vector due to the formation of stable complexes with desirable physical characteristics, low toxicity and able to carry high amount of siRNA or DsiRNA.

Matched MeSH terms: Transfection/methods*
Fulltext A guide in lentiviral vector production for hard-to-transfect cells, using cardiac-derived c-kit expressing cells as a model system

Kalidasan V, Ng WH, Ishola OA, Ravichantar N, Tan JJ, Das KT

Sci Rep, 2021 Sep 28;11(1):19265.
PMID: 34584147 DOI: 10.1038/s41598-021-98657-7

Gene therapy revolves around modifying genetic makeup by inserting foreign nucleic acids into targeted cells via gene delivery methods to treat a particular disease. While the genes targeted play a key role in gene therapy, the gene delivery system used is also of utmost importance as it determines the success of gene therapy. As primary cells and stem cells are often the target cells for gene therapy in clinical trials, the delivery system would need to be robust, and viral-based entries such as lentiviral vectors work best at transporting the transgene into the cells. However, even within lentiviral vectors, several parameters can affect the functionality of the delivery system. Using cardiac-derived c-kit expressing cells (CCs) as a model system, this study aims to optimize lentiviral production by investigating various experimental factors such as the generation of the lentiviral system, concentration method, and type of selection marker. Our findings showed that the 2nd generation system with pCMV-dR8.2 dvpr as the packaging plasmid produced a 7.3-fold higher yield of lentiviral production compared to psPAX2. Concentrating the virus with ultracentrifuge produced a higher viral titer at greater than 5 × 105 infectious unit values/ml (IFU/ml). And lastly, the minimum inhibitory concentration (MIC) of puromycin selection marker was 10 μg/mL and 7 μg/mL for HEK293T and CCs, demonstrating the suitability of antibiotic selection for all cell types. This encouraging data can be extrapolated and applied to other difficult-to-transfect cells, such as different types of stem cells or primary cells.

Matched MeSH terms: Transfection/methods*
Fulltext Evaluation of two transformation protocols and screening of positive plasmid introduction into Bacillus cereus EB2, a gram-positive bacterium using qualitative analyses

Sirajuddin SA, Sundram S

Braz J Microbiol, 2020 Sep;51(3):919-929.
PMID: 32078730 DOI: 10.1007/s42770-020-00241-0

Both Gram-positive and Gram-negative bacteria can take up exogenous DNA when they are in a competent state either naturally or artificially. However, the thick peptidoglycan layer in Gram-positive bacteria's cell wall is considered as a possible barrier to DNA uptake. In the present work, two transformation techniques have been evaluated in assessing the protocol's ability to introduce foreign DNA, pBBRGFP-45 plasmid which harbors kanamycin resistance and green fluorescent protein (GFP) genes into a Gram-positive bacterium, Bacillus cereus EB2. B. cereus EB2 is an endophytic bacterium, isolated from oil palm roots. A Gram-negative bacterium, Pseudomonas aeruginosa EB35 was used as a control sample for both transformation protocols. The cells were made competent using respective chemical treatment to Gram-positive and Gram-negative bacteria, and kanamycin concentration in the selective medium was also optimized. Preliminary findings using qualitative analysis of colony polymerase chain reaction (PCR)-GFP indicated that the putative positive transformants for B. cereus EB2 were acquired using the second transformation protocol. The positive transformants were then verified using molecular techniques such as observation of putative colonies on specific media under UV light, plasmid extraction, and validation analyses, followed by fluorescence microscopy. Conversely, both transformation protocols were relatively effective for introduction of plasmid DNA into P. aeruginosa EB35. Therefore, this finding demonstrated the potential of chemically prepared competent cells and the crucial step of heat-shock in foreign DNA transformation process of Gram-positive bacterium namely B. cereus was required for successful transformation.

Matched MeSH terms: Transfection/methods*
Fulltext Advancements in reprogramming strategies for the generation of induced pluripotent stem cells

Lai MI, Wendy-Yeo WY, Ramasamy R, Nordin N, Rosli R, Veerakumarasivam A, et al.

J Assist Reprod Genet, 2011 Apr;28(4):291-301.
PMID: 21384252 DOI: 10.1007/s10815-011-9552-6

Direct reprogramming of somatic cells into induced pluripotent stem (iPS) cells has emerged as an invaluable method for generating patient-specific stem cells of any lineage without the use of embryonic materials. Following the first reported generation of iPS cells from murine fibroblasts using retroviral transduction of a defined set of transcription factors, various new strategies have been developed to improve and refine the reprogramming technology. Recent developments provide optimism that the generation of safe iPS cells without any genomic modification could be derived in the near future for the use in clinical settings. This review summarizes current and evolving strategies in the generation of iPS cells, including types of somatic cells for reprogramming, variations of reprogramming genes, reprogramming methods, and how the advancement iPS cells technology can lead to the future success of reproductive medicine.

Matched MeSH terms: Transfection/methods*
Inhibition of lysosomal vacuolar proton pump down-regulates cellular acidification and enhances E. coli bactofection efficiency

Akinsola RO, Lee CW, Sim EUH, Narayanan K

Anal Biochem, 2021 03 01;616:114088.
PMID: 33358938 DOI: 10.1016/j.ab.2020.114088

Endosomal escape is considered a crucial barrier that needs to be overcome by integrin-mediated E. coli for gene delivery into mammalian cells. Bafilomycin, a potent inhibitor of the H+ proton pump commonly employed to lower endosomal pH, was evaluated as part of the E. coli protocol during delivery. We found an increase in green fluorescent protein expression up 6.9, 3.2, 5.0, 2.8, and 4.5 fold in HeLa, HEK-293, A549, HT1080, and MCF-7 respectively, compared to untreated cells. Our result showed for the first time that Inhibition of lysosomal V-ATPase enhances E. coli efficiency.

Matched MeSH terms: Transfection/methods
Roles of MicroRNA21 and MicroRNA29a in Regulating Cell Adhesion Related Genes in Bone Metastasis Secondary to Prostate Cancer

Mohamad M, Wahab NA, Yunus R, Murad NA, Zainuddin ZM, Sundaram M, et al.

Asian Pac J Cancer Prev, 2016;17(7):3437-45.
PMID: 27509989

BACKGROUND: There is an increasing concern in the role of microRNA (miRNA) in the pathogenesis of bone metastasis (BM) secondary to prostate cancer (CaP). In this exploratory study, we hypothesized that the expression of vinculin (VCL) and chemokine X3C ligand 1 (CX3CL1) might be downregulated in clinical samples, most likely due to the posttranscriptional modification by microRNAs. Targeted genes would be upregulated upon transfection of the bone metastatic prostate cancer cell line, PC3, with specific microRNA inhibitors.
MATERIALS AND METHODS: MicroRNA software predicted that miR21 targets VCL while miR29a targets CX3CL1. Twenty benign prostatic hyperplasia (BPH) and 16 high grade CaP formalinfixed paraffin embedded (FFPE) specimens were analysed. From the bone scan results, high grade CaP samples were further classified into CaP with no BM and CaP with BM. Transient transfection with respective microRNA inhibitors was done in both RWPE1 (normal) and PC3 cell lines. QPCR was performed in all FFPE samples and transfected cell lines to measure VCL and CX3CL1 levels.
RESULTS: QPCR confirmed that VCL messenger RNA (mRNA) was significantly down regulated while CX3CL1 was upregulated in all FFPE specimens. Transient transfection with microRNA inhibitors in PC3 cells followed by qPCR of the targeted genes showed that VCL mRNA was significantly up regulated while CX3CL1 mRNA was significantly downregulated compared to the RWPE1 case.
CONCLUSIONS: The downregulation of VCL in FFPE specimens is most likely regulated by miR21 based on the in vitro evidence but the exact mechanism of how miR21 can regulate VCL is unclear. Upregulated in CaP, CX3CL1 was found not regulated by miR29a. More microRNA screening is required to understand the regulation of this chemokine in CaP with bone metastasis. Understanding miRNAmRNA interactions may provide additional knowledge for individualized study of cancers.

Matched MeSH terms: Transfection/methods
Fulltext Gene expression profiles in primary duodenal chick cells following transfection with avian influenza virus H5 DNA plasmid encapsulated in silver nanoparticles

Jazayeri SD, Ideris A, Shameli K, Moeini H, Omar AR

Int J Nanomedicine, 2013;8:781-90.
PMID: 23459681 DOI: 10.2147/IJN.S39074

In order to develop a systemically administered safe and effective nonviral gene delivery system against avian influenza virus (AIV) that induced cytokine expression, the hemagglutinin (H5) gene of AIV, A/Ck/Malaysia/5858/04 (H5N1) and green fluorescent protein were cloned into a coexpression vector pIRES (pIREGFP-H5) and formulated using green synthesis of silver nanoparticles (AgNPs) with poly(ethylene glycol) and transfected into primary duodenal cells taken from 18-day-old specific-pathogen-free chick embryos. The AgNPs were prepared using moderated temperature and characterized for particle size, surface charge, ultraviolet-visible spectra, DNA loading, and stability. AgNPs and AgNP-pIREGFP-H5 were prepared in the size range of 13.9 nm and 25 nm with a positive charge of +78 ± 0.6 mV and +40 ± 6.2 mV, respectively. AgNPs with a positive surface charge could encapsulate pIREGFP-H5 efficiently. The ultraviolet-visible spectra for AgNP-pIREGFP-H5 treated with DNase I showed that the AgNPs were able to encapsulate pIREGFP-H5 efficiently. Polymerase chain reaction showed that AgNP-pIREGFP-H5 entered into primary duodenal cells rapidly, as early as one hour after transfection. Green fluorescent protein expression was observed after 36 hours, peaked at 48 hours, and remained stable for up to 60 hours. In addition, green fluorescent protein expression generally increased with increasing DNA concentration and time. Cells were transfected using Lipocurax in vitro transfection reagent as a positive control. A multiplex quantitative mRNA gene expression assay in the transfected primary duodenal cells via the transfection reagent and AgNPs with pIREGFP-H5 revealed expression of interleukin (IL)-18, IL-15, and IL-12β.

Matched MeSH terms: Transfection/methods*

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