Developing a Novel Gene-Delivery Vector System Using the Recombinant Fusion Protein of Pseudomonas Exotoxin A and Hyperthermophilic Archaeal Histone HPhA

Non-viral gene delivery system with many advantages has a great potential for the future of gene therapy. One inherent obstacle of such approach is the uptake by endocytosis into vesicular compartments. Receptor-mediated gene delivery method holds promise to overcome this obstacle. In this study, we developed a receptor-mediated gene delivery system based on a combination of the Pseudomonas exotoxin A (PE), which has a receptor binding and membrane translocation domain, and the hyperthermophilic archaeal histone (HPhA), which has the DNA binding ability. First, we constructed and expressed the rPE-HPhA fusion protein. We then examined the cytotoxicity and the DNA binding ability of rPE-HPhA. We further assessed the efficiency of transfection of the pEGF-C1 plasmid DNA to CHO cells by the rPE-HPhA system, in comparison to the cationic liposome method. The results showed that the transfection efficiency of rPE-HPhA was higher than that of cationic liposomes. In addition, the rPE-HPhA gene delivery system is non-specific to DNA sequence, topology or targeted cell type. Thus, the rPE-HPhA system can be used for delivering genes of interest into mammalian cells and has great potential to be applied for gene therapy.     

Sequence of an operon containing a novel δ-endotoxin gene from Bacillus thuringiensis

An insect larval toxin designated CryII is produced by several subspecies of Bacillus thuringiensis and differs from the other major delta-endotoxins in these bacteria in its size, toxicity profile and presence as part of an operon with three open reading frames (ORF). Such an operon from a novel B. thuringiensis isolate has been cloned and differs from one previously characterized in the following ways: (a) the size and number of amino acid repeats in one of the ORFs; (b) the smaller size of the CryII protoxin and the presence of a unique 110-kDa CryII-related antigen; and (c) high larvicidal activity for a particular Lepidopteran but low activity for a Dipteran. Various subclones of this operon were introduced into a plasmid-free B. thuringiensis strain and only the cryII gene was found to be necessary for protoxin accumulation.     

Insights into protective effects of medium additives on animal cells under fluid stresses: the hydrophobic interactions

Animal cells in suspension culture can suffer severe mechanical damage from bursting gas bubbles or other hydrodynamic force sources. Certain chemical additives in the culture media, particularly some surface-active chemicals, can effectively protect animal cells against such damage. Previously we proposed that the protective effect is associated with the adsorption of the additives in the cell membrane through hydrophobic binding of the surface-active molecules to the membrane. Adsorption of the additives to the cell membrane may lead to decreased hydrophobicity of the cell surface, thus eliminating cell adhesion to bubbles and reducing cell damage from bursting bubbles. In this study, we measured the hydrophobicity of two insect cell lines based on cell adhesion to hydrocarbon phase and its influence by surface-active chemicals, Pluronic F68, a methylcellulose and a polyethylene glycol. The experimental results showed strong support for the aforecited cell protection mechanism.     

Effects of Rahnella aquatilis JZ-GX1 on Treat Chlorosis Induced by Iron Deficiency in Cinnamomum camphora

Journal of Plant Growth Regulation - With the increasing popularity of urban landscaping, there is a greater need to address iron deficiency and chlorosis in Cinnamomum camphora. Beneficial...     

Self-assembly of Large-scale Two-dimensional Plasmonic Superlattices Based on Single-Crystal Au Nanospheres and the FDTD Simulation of Its Optical Properties

Plasmonics - Large-scale ordered two-dimensional (2D) superlattices at oil/water interface were fabricated using single-crystal Au nanospheres (NSs) with different diameters as building blocks. A...