1-2. (a) Let u, v ∈ S and suppose that uv = 0; then u = 0 or v = 0 since u, v ∈ R and R is an integral domain. Consider the unit homomorphisms η : Z −→ R and η′ : Z −→ S. Then for n ∈ Z, η′(n) = η(n), so ker η′ = ker η and therefore charS = charR. (b) Q is a field and Z ⊆ Q is a subring which is not a field. 1-3. (a) For any subring R ⊆ C, R is an integral domain with characteristic subring Z a...

Cytochalasin is known to inhibit cytoplasmic streaming rapidly in characean cells without disassembling their actin bundles. Lower cytochalasin concentrations than those needed for streaming inhibition are now shown to disrupt bundle assembly and, over longer periods, assembled bundles. After local wounding, cytochalasin limited bundle regeneration to the production of polygons and straight, di...

Plasma membranes were isolated using the aqueous polymer two-phase partition method from the algae Chara corallina and Chara longifolia, algae which differ in their ability to grow in saline environments. Enrichment of plasma membrane and depletion of tonoplast relative to the microsomal fraction was monitored using phosphohydrolase assays and cross-reactions to antibodies raised against higher...

Internodal cells of Chara were separated with a Plexiglas divider into two segments and the vibrating probe was used to investigate the extracellular current profiles that formed along these two surfaces. Treating one segment of the Chara cell with K(+) concentrations greater than 2 millimolar caused a dramatic reduction in the extracellular current pattern in this compartment. Concentrations o...

Popularly known as stoneworts, brittleworts, muskgrass, muskworts or bass-weeds, Characeae are among the largest and most complex green algae. All common names come from some characteristics these plants may exhibit, such as the brittle, limestone (calcium carbonate) exoskeleton that can form on the external surfaces of the plant (e.g. Chara vulgaris and Chara globularis) and, particularly, fro...

This paper studies the possibility of using WaTEM/SEDEM model to assess sediment yield from catchment area within Lena River catchment. The study was carried out based on a comparison predicted data and measured suspended at gauging stations state monitoring network Russia. performed two areas, with plain mountainous relief. first site is located river Chara an 4150 km2. second rests between Ta...

An apparatus is described by means of which the power versus frequency spectrum of the photomultiplier current can be obtained for laser light scattered by streaming cytoplasm in the algal cell Chara corallina. A Doppler peak is noted in the spectrum which is abolished when cytoplasmic streaming is arrested by electrical stimulation. For 5 cells of Chara, this simple laser-Doppler velocimeter g...