Isolation and fractionation of total nucleic acids from tissues and cells

A simple and efficient method was devised to permit the isolation of total nucleic acids (poly(A+) and poly(A-) RNAs and DNA) from cells and tissues (e.g. testis) enriched in DNA. Chaotropic reagents (guanidine thiocyanate and LiBr) were utilized to inactivate nucleases rapidly, minimize the viscosity of the homogenization solution and to precipitate RNA selectively (LiBr). Both total and poly(A+)-enriched mRNAs were recovered in a biologically active form as demonstrated by their ability to programme an in vitro translation reaction. High molecular weight DNA (greater than 22 kilobases) was recovered from the LiBr-soluble supernatants by selective ethanol precipitation, subsequently purified and was in a form suitable for further biochemical analysis.     

Uptake of proline in cultured cells from patients with Lowes syndrome

When cultured cells from patients with Lowe's syndrome were incubated for short periods of time in phosphate-buffered saline, they reveal a marked increase in accumulation of [¹⁴C]proline. No differences were observed in the uptake of glycine, glutamate and lysine. Although the mechanism for the increased proline uptake by affected cells under these special conditions is not known, this phenomenon may be useful in delineating the Lowe's phenotype.     

An alkaline approach to treating cooling towers for control of Legionella pneumophila.

Earlier field and laboratory studies have shown that Legionella species survive and multiply in the pH range 5.5 to 9.2. Additionally, the technical feasibility of operating cooling towers at elevated alkalinities and pH has previously been documented by published guidelines. The guidelines indicate that these conditions facilitate corrosion control and favor chlorine persistence which enhances the effectiveness of continuous chlorination in biofouling control. This information suggests that control of Legionella species in cooling towers can be accomplished by operating the towers under alkaline conditions. To test this possibility, we collected water samples over a period of months from a hospital cooling tower. The samples were analyzed for a variety of chemical parameters. Subsamples were pasteurized and inoculated with non-agar-passaged Legionella pneumophila which had been maintained in tap water. Correlation of subsequent Legionella growth with corresponding pH and alkalinity values revealed statistically significant inverse associations. These data support the hypothesis that operating cooling towers outside of the optimal conditions for Legionella growth (e.g., at elevated alkalinities and a pH greater than 9) may be a useful approach to controlling growth in this habitat.