Transferrinfection. A Highly Efficient Way to Express Gene Constructs in Eukaryotic Cells

No abstract available

Transferrin-polycation-DNA complexes. The effect of polycations on the structure of the complex and DNA delivery to cells.

We have previously described a gene delivery system based upon the receptor-mediated endocytosis of DNA complexed with transferrin-polycation conjugates. This delivery system has been found to be very effective for both the internalization and the expression of genetic material in cells that have many transferrin receptors. Upon scrutinization of the parameters involved in this method, which we have termed transferrinfection, we note two important features of the process: the polycation in polycation-transferrin conjugates, as expected, serves to attach the transferrin moiety to the DNA and, in addition, the polycation functions to condense the DNA into a doughnut structure. Electron microscopic analysis of a range of poorly active to highly active transferrinfection samples reveals a strong correlation between DNA condensation and cellular DNA uptake. Furthermore, we demonstrate that the transfection activity of the DNA complex can be increased by addition of free polycation as long as a sufficient quantity of polycation-transferrin conjugates remains in the complex to ensure its binding to the cellular receptor

The group theoretic Rubik\u27s Cube

Cyclic fads often boomerang our childhood toys, sending them back to us with renewed popularity during our adulthood. Recently, Rubik\u27s Cube has made a startling comeback and is once again a staple in most toy stores. Invented by Erno Rubik in his hometown of Budapest, Hungary, the original \Magic Cube was released in 1974. Upon its world debut in 1980, the toy named after this Hungarian architect became an instant classic. Over 350 billion Rubik\u27s Cubes have been sold worlwide [sic] over the past 30 years, making it easily the top-selling puzzle toy in documented history. This seemingly innocuous puzzle has frazzled countless children, and perhaps even more adults. The mathematical complexity of the Cube attracted group theorists and other mathematicians upon its release over three decades ago, and the many layers of its structure continue to intrigue the mathematics community. Most of us place emphasis on unscralmbing [sic] the Cube, solving the puzzle. Rather than focusing on the construction of algorithms or solutions to the Cube, we chose to take a group theoretic approach to analyzing this infamous toy. Here, treating Rubik\u27s Cube as a group, we will examine subgroups of the Cube, particularly those constructed via semidirect products. These constructions aid us in describing the possible color arrangements of the Cube

Reducing Sedentary Behaviour In University Students Using A Text Message-Based Intervention

Sedentary behaviour (SB) has been linked to many health problems (e.g., type 2 diabetes, heart disease). Interventions aimed at office workers, overweight and obese individuals have proven successful in reducing SB; however, no studies have examined university students. Text message-based interventions have succeeded to aid in smoking cessation and increase both physical activity and healthy eating, but have not been shown to reduce SB. Eighty-two university students were randomized into intervention (SB related text messages) or control (text messages unrelated to SB) groups. Participants received daily text messages and reported various SBs (i.e., breaks from sitting, standing, light and moderate intensity physical activity) at four time points (baseline, 2, 4 and 6 weeks). Small to moderate effects that either approached or did not reach significance were found that consistently favored the intervention group for all SB measures. Findings suggest text messages have the potential to reduce SB in university students

Lipopolysaccharide is a frequent contaminant of plasmid DNA preparations and can be toxic to primary cells in the presence of adenovirus

Endotoxin (lipopolysaccharide, LPS) is commonly found as a contaminant in plasmid DNA preparations. We demonstrate here that the quantities of LPS typically contaminating DNA preparations can generate a toxicity to primary cells (primary human skin fibroblasts, primary human melanoma cells) in the presence of entry-competent adenovirus particles. Toxicity can be observed with as little as 100 ng/ml free LPS or 100 pg/ml LPS when the LPS is assembled into polylysine/adenovirus complexes. Simple and effective methods of removing the contaminating LPS using either a polymyxin B resin or Triton X-114 extraction are described. Treatment of DNA samples to remove LPS eliminates the toxicity to primary cells