The nucleus is one of the most prominent cellular organelles, yet surprisingly little is known about how it is formed, what determines its shape and what defines its size. As the nuclear envelope (NE) disassembles in each and every cell cycle in metazoans, the process of rebuilding the nucleus is crucial for proper development and cell proliferation. In this Commentary, we summarize what is kno...

We present high resolution radio observations of the nuclear radio emission in a sample of eight radio galaxies having Megaparsec sizes, using the European VLBI network at 18 cm. At a resolution of 25 mas we detect all the giant radio galaxies from our sample. Among themDA 240 and 1331−099 were imaged for an extended period. These observations reveal a twin-jet structure for DA 240 and one-side...

Nuclear-size corrections of order (Zα)5 and (Zα)6 to the S-state levels of hydrogenic atoms are considered. These nuclear-elastic contributions are somewhat smaller than the polarizability (nuclear-inelastic) corrections for deuterium, but are of comparable or larger size for the hydrogen case. For deuterium the (attractive) nonrelativistic (Zα)5 correction to the 2S-1S transition is −0.49 kHz,...

The first nuclear bomb detonation on Earth involved a plutonium implosion-type device exploded at the Trinity test site (33°40'38.28″N, 106°28'31.44″W), White Sands Proving Grounds, near Alamogordo, New Mexico. Melting and subsequent quenching of the local arkosic sand produced glassy material, designated "Trinitite". In cross section, Trinitite comprises a thin (1-2 mm), primarily glassy surfa...

We present a new catalog of absolute nuclear magnitudes of Jupiter family (JF) comets, which is an updated version of our previous catalog (Tancredi et al. 2000). The full version of the catalog can be accessed on line at http://www.fisica.edu.uy/∼gonzalo/catalog. From the new catalog we find a linear cumulative luminosity function (CLF) of slope 0.54 ± 0.03 for JF comets with q < ∼ 2.5 AU. By ...

Protein-NLS-coated gold particles up to approximately 250 A in diameter are transported through the nuclear pores in normal, proliferating BALB/c 3T3 cells. This size can increase or decrease, depending on cellular activity. It has been suggested that increases in functional pore size are related to a reduction in the amount of available p53. To further test this hypothesis, we investigated the...

We have reported previously that the prototype foamy virus (PFV) integrase (IN) has a strong nuclear localization signal (NLS) in its C-terminal domain, in particular in a region of aa 306-334 including highly karyophilic arginines or lysines at positions 308, 313, 318, 324, and 329. In this study, we used various mutants of the C-terminal domain to further analyze its karyophilic determinants....

The influence of molecular diffusion on the nuclear magnetic resonance (NMR) signal can be exploited to estimate compartment size distributions in heterogeneous specimens. Theoretical relationships between the NMR signal intensity at long diffusion times and the moments of a general distribution of isolated pores with characteristic shapes (planar, cylindrical or spherical) are established. A n...

BACKGROUND DNA flow cytometry describes the use of flow cytometry for estimation of DNA quantity in cell nuclei. The method involves preparation of aqueous suspensions of intact nuclei whose DNA is stained using a DNA fluorochrome. The nuclei are classified according to their relative fluorescence intensity or DNA content. Because the sample preparation and analysis is convenient and rapid, DNA...

Eukaryotic cells have an "awareness" of their volume and organellar volumes, and maintain a nuclear size that is proportional to the total cell size. New studies in budding and fission yeast have examined the relationship between cell and nuclear volumes. It was found that the size of the nucleus remains proportional to cell size in a wide range of genetic backgrounds and growth conditions that...