Watson and Crick (1953), and Kornberg (1967). The author assumes no prior knowledge. For example when discussing the observations of Meselson and Stahl not only does he include the usual symbolic illustrations of semiconservative DNA replication, but also a figure of equilibrium density gradient centrifugation. Each chapter ends with a summary of the observations presented which answer the orig...

The origin of the density heterogeneity of platelets was studied by measuring the survival of density subpopulations of rabbit platelets separated by discontinuous Stractan density gradient centrifugation. When a total population of 5tCr-labeled platelets was injected into recipient rabbits. the relative specific radioactivity of the most dense platelets decreased rapidly. In contrast. that of ...

Myocardial cells were isolated after treatment with collagenase (0.05%) and hyaluronidase (0.1%) by discontinuous-gradient centrifugation on 3% Ficoll. Nuclei derived from these myocardial cells were then fractionated on a discontinuous sucrose density gradient with the following steps: (I) 2.0M/2.3M, (II) 2.3M/2.4M, (III) 2.4M/2.5M, (IV) 2.5M/2.6M, and (V) 2.6M/2.85M. The myocardial nuclei wer...

The decline of species richness from equator to pole, or latitudinal diversity gradient (LDG), is nearly universal among clades of living organisms, yet whether it was such a pervasive pattern in the geologic past remains uncertain. Here, we calculate the strength of the LDG for terrestrial mammals in North America over the past 65 My, using 27,903 fossil occurrences of Cenozoic terrestrial mam...

A rapid, simple method for nuclei isolation and purification from soybean (Glycine max L. Merr.) protoplasts is described. The isolated nuclei exhibited active amino acid incorporation and RNA synthesis, but DNA synthesis was not detectable. Analysis by CsCl density gradient centrifugation showed that DNA isolated from nuclei had a single band, while DNA isolated from protoplasts consisted of t...

Time-lapse resistivity measurements and groundwater geochemistry were used to study salinity effect on groundwater aquifer at the ex-promontory-land of Carey Island in Malaysia. Resistivity was measured by ABEM Terrameter SAS4000 and ES10-64 electrode selector. Relationship between earth resistivity and total dissolved solids (TDS) was derived, and with resistivity images, used to identify wate...

A method has been developed to isolate plasma membranes with high ATPase activity from wild type Neurospora. Cells are treated with snail enzyme to weaken their cell walls, disrupted by gentle homogenization in a medium designed to keep mitochondria and other organelles intact, and fractionated by differential centrifugation. After removal of mitochondria, several higher speed particulate fract...

Adenovirus vectors (rAd) are widely used in gene therapy to deliver genes of interest. It is therefore essential to develop a purification process that clears the adenovirus of undesired contaminants while purifying high titre stock adenovirus. The current standard method of purification uses a CsCl density gradient, which is formed during centrifugation. The limitations of this procedure inclu...

Breakage and fractionation of respiratory competent yeast in the presence of ethidium bromide, and subsequent centrifugation of a detergent lysate of the mitochondrial fraction by the dye-buoyant-density technique, results in the isolation of closed-circular DNA. After removal of bound dye, this DNA has two components when analyzed by equilibrium buoyant density in the analytical ultracentrifug...