In previous equilibrium binding studies, Dictyostelium discoideum plasma membranes have been shown to bind actin and to recruit actin into filaments at the membrane surface. However, little is known about the kinetic pathway(s) through which actin assembles at these, or other, membranes. We have used actin fluorescently labeled with N-(1-pyrenyl)iodoacetamide to examine the kinetics of actin as...

in this paper, the nucleation and growth of diamond/diamond-like coatings on austenitic (aisi 316) and ferritic (aisi 430) stainless steel substrates have been investigated using torch technique. the effects of substrate surface preparation has also been studied. the quality of coatings produced has been examined using optical and scanning electron microscopy, x-ray diffraction, raman spectrosc...

Steinernema feltiae is a moderately freezing tolerant nematode, that can withstand intracellular ice formation. We investigated recrystallization inhibition, thermal hysteresis and ice nucleation activities in the infective juveniles of S. feltiae. Both the splat cooling assay and optical recrystallometry indicate the presence of ice active substances that inhibit recrystallization in the nemat...

Actin polymerization essential for endocytic internalization in budding yeast is controlled by four nucleation promoting factors (NPFs) that each exhibits a unique dynamic behavior at endocytic sites. How each NPF functions and is regulated to restrict actin assembly to late stages of endocytic internalization is not known. Quantitative analysis of NPF biochemical activities, and genetic analys...

Cell motility depends on the rapid growth of cortical actin filaments whose barbed ends are capped in the resting cell. High speed supernates (HSS) of dilute neutrophil lysates contain actin monomers and/or oligomers that can be induced to polymerize by certain stimuli. We questioned whether some of the actin remaining in the supernate after high speed centrifugation exists as occult nucleation...

It is well known that exposure to environmental cadmium causes itai-itai (ouch-ouch) disease. However, the exact mechanism underlying this bone disease remains unresolved. By focusing on the calcification mechanism, we examined developing tooth enamel in rats exposed to cadmium to test the hypothesis that cadmium exposure may cause defects in crystal formation. Electron microscopy revealed the ...

Wintering flower buds of cold hardy Rhododendron japonicum cooled slowly to subfreezing temperatures are known to undergo extraorgan freezing, whose mechanisms remain obscure. We revisited this material to demonstrate why bud scales freeze first in spite of their lower water content, why florets remain deeply supercooled and how seasonal adaptive responses occur in regard to extraorgan freezing...