ABSTRACT
Purpose@#Newcastle disease (ND) represents a major viral disease across the world which imposes high costs to poultry producers for vaccination. Hemagglutinin-neuraminidase (HN) and fusion (F) proteins are the major immunogenic epitopes of Newcastle disease virus and hence, have been the main targets for development of anti-ND vaccines. This paper reports transient expression of a synthetic gene composing of four tandem repeats of HN and three tandem repeats of F epitopes in maize leaves as initial step toward production of recombinant vaccine against ND. @*Materials and Methods@#The synthetic gene was cloned in pBI121 plasmid to yield an expression vector. The vector was sophisticated by the addition of AUG codon, polyhistidine-tag, tobacco mosaic virus omega sequence, stop codon, and restriction sites. Leaf transformation was conducted by the agroinfiltration method. Molecular detection assays including polymerase chain reaction, reverse transcription-polymerase chain reaction and enzyme-linked immunosorbent assay (ELISA) were carried out to evaluate transgene expression in infiltrated leaves of the corn plant. @*Results@#The result obtained in this research revealed that the transgene was transcribed and translated in maize leaves only 48 hours after infiltration. In the second phase of the experiment, the expressed protein was injected into rabbits. The result of the ELISA assay indicated induction of immune response in the rabbits after injection with the heterologous protein. @*Conclusion@#These results confirm the feasibility of agroinfiltration for transient gene expression of viral epitopes in monocot plants which naturally resist stable transformation by Agrobacterium tumefaciens. Practical implications of this finding are discussed in detail and some recommendations for future studies are proposed.
ABSTRACT
Background: It is well documented that Silver Nanoparticles [SNPs] are potent antimicrobial agents. However, little is known about antimicrobial effects of biologically synthesized SNPs at molecular level. In the present study, efficacy of the green microalgae Chlorella vulgaris in biosynthesis of silver nanoparticles and inhibitory effect of the biosynthesized SNPs on growth and virulence of Staphylococcus aureus [S. aureus] were investigated
Methods: Algal suspension was incubated in the presence of silver nitrate to induce formation of nanoparticles. The experiment was conducted under a pH range to evaluate pH effect on the shape and properties of nanoparticles. Characterization was performed by Transmission Electron Microscopy [TEM], Scanning Electron Microscopy [SEM], Energy Dispersive Spectrometry [EDS] and X-ray diffraction analysis [XRD]. Moreover, concentration of biosynthesized SNPs was measured by high resolution ICP-OES spectrometer. Antibacterial effect of SNPs on growth of S. aureus was evaluated by broth micro-dilution method. Inhibitory effect of SNPs on alpha hemolysin, a well-known virulence factor of S. aureus was investigated through real time PCR assay
Results: Spherical SNPs were produced with characteristic monodispersity at low and neutral pHs; however, in alkaline condition, nanorod structures were formed. SNPs inhibited growth of S. aureus at concentration of 50 microg/ml. Alpha hemolysin expression was also effectively inhibited by SNPs treatment
Conclusion: In general, results revealed formation of spherical silver nanoparticles with inhibitory effects on bacterial growth and antagonist activity on the expression of alpha hemolysin. Moreover, increase in pH to basic condition resulted in aggregation of nanoparticles and formation of rod-like nanostructures
ABSTRACT
Transient and stable transformation of host plants are the common techniques to produce transgenic plants. However, the main drawback of stable transformation is the fact that it takes quite a long time to produce a transgenic line. While, transient gene expression is a quick method to produce recombinant proteins in plants. The main goal of the present study was to evaluate efficient agroinfiltration as an efficient and rapid method for production of recombinant antigen of FMDV. Tobacco leaves were transformed via agroinfiltration using a needle-free syringe. Presence of the gene cassette was verified by polymerase chain reaction [PCR]. Expression of the foreign gene was evaluated using Real Time PCR, protein dot blot and enzyme-linked immunosorbent assay [ELISA]. PCR analysis confirmed successful transformation of plant leaves. Expression of foreign protein was confirmed at both transcription and translation levels. Results of Real Time PCR assay indicated that the foreign gene was transcribed in transformed leaves. ELISA results showed that the foreign gene was expressed in the transformed leaves in high level. Here, the efficacy of agroinfiltration for transient expression of FMDV coat protein in tobacco was illustrated. Accordingly, transient agroinfilteration expedites the process of recombinant antigens expression in plant tissues