The formation of kinks in a loop of bundled polyelectrolyte filaments is analyzed in terms of the thermal fluctuations of charge density due to polyvalent counterions adsorbed on the polyelectrolyte filaments. It is found that the counterion-mediated attraction energy of filaments depends on their bending. By consideration of curvature elasticity energy and counterion-mediated attraction betwee...

The nonthermal filaments in the Galactic Center constitute one of the great mysteries of this region of the Galaxy. We summarise the observational data on these filaments and critically review the various theories which currently outnumber the observed filaments. We summarise out theory for the longest of these filaments, the Snake, and discuss the relevance of this model for the other filament...

Connectin (also called titin) is a huge, striated muscle protein that binds to thick filaments and links them to the Z-disc. Using an mAb that binds to connectin in the I-band region of the molecule, we studied the behavior of connectin in both relaxed and activated skinned rabbit psoas fibers by immunoelectron microscopy. In relaxed fibers, antibody binding is visualized as two extra striation...

Nuclear lamina and matrices were prepared from sperm pronuclei assembled in Xenopus egg extracts using a fractionation and extraction procedure. Indirect immunofluorescence revealed that while chromatin was efficiently removed from nuclei during the extraction procedure, the distribution of lamins was unaffected. Consistent with this data, the amount of lamin B3, determined by immunoblotting, w...

Surface properties of monofilaments can be tailored with radial structural gradients, which is specific interest for technical textile applications. Radial gradients in fine (≤ 40 μm thick) poly(ethylene terephthalate) have been studied high-resolution Raman mapping and one-dimensional microbeam small-angle x-ray scattering tomography. Filaments melt-spun by using online offline drawing techniq...

Astroglial filaments approximately 10 nm in diameter were isolated from degenerated mouse optic nerves by Triton X-100 and DNase I treatments followed by sucrose density gradient centrifugation. 2-4 wk after bilateral enucleation, optic nerves contained virtually a single population of 10-nm filaments (astroglial filaments), free from neurofilaments. In negative-staining and thin-section electr...

Actin filaments that serve as "rails" for the myosin-based transport of membrane organelles [1-4] continuously turn over by concurrent growth and shortening at the opposite ends [5]. Although it is known that dynamics of actin filaments is essential for many of the actin cytoskeleton functions, the role of such dynamics in myosin-mediated organelle transport was never studied before. Here, we a...

Lavender is a mutation of chick neural-crest-derived melanocytes showing dilute feather pigmentation. This defect, previously attributed to a lack or attenuation of dendrites, was found to be due to a defect in melanosome translocation. The mutant phenotype, of melanincongested perikarya and pigmentless dendrites is expressed both in vivo and in vitro. Studies with colcemid and cytochalasin B s...

The traditional Fourier-Bessel approach to three-dimensional reconstruction from electron microscopic (EM) images of helical polymers involves averaging over filaments, assuming a homogeneous structure and symmetry. We have used a real-space reconstruction approach to study the EspA filaments formed by enteropathogenic E. coli. In negative stain, the symmetry of these filaments is ambiguous, an...

Several and various types of cells contain fine cytoplasmic filaments closely resembling the myofilaments of muscle cells (2, 18, 23, 24). In many of these cells and especially when cultured, it has been demonstrated that some of these filaments react with heavy meromyosin (HMM) in the same way as do the actin filaments of muscle cells (3, 6 7). This suggests that these filaments may be actinoi...