Elongation rate and heat produced by Avena coleoptile segments suspended in sucrose buffer solutions were measured at pH values from 3.5 to 8.5. The caloric efficiency of elongation (CEE) was defined as the ratio of the rate of elongation to the rate of heat production. Elongation and CEE were greatest at intermediate pH values, but heat production (about 1 cal/g.hr) was insensitive to pH withi...

Mammary branching morphogenesis is regulated by receptor tyrosine kinases (RTKs). We sought to determine how these RTK signals alter proliferation and migration to accomplish tube elongation in mouse. Both behaviors occur but it has been difficult to determine their relative contribution to elongation in vivo, as mammary adipocytes scatter light and limit the depth of optical imaging. According...

Caulobacter crescentus cells treated with amdinocillin, an antibiotic which specifically inhibits the cell elongation transpeptidase penicillin binding protein 2 in Escherichia coli, exhibit defects in stalk elongation and morphology, indicating that stalk synthesis may be a specialized form of cell elongation. In order to investigate this possibility further, we examined the roles of two other...

It has long been thought that traction exerted by filopodia of secondary mesenchyme cells (SMCs) is a sufficient mechanism to account for elongation of the archenteron during sea urchin gastrulation. The filopodial traction hypothesis has been directly tested here by laser ablation of SMCs in gastrulae of the sea urchin, Lytechinus pictus. When SMCs are ablated at the onset of secondary invagin...

In plants, basic helix-loop-helix (bHLH) transcription factors play important roles in the control of cell elongation. Two bHLH proteins, PACLOBTRAZOL RESISTANCE1 (PRE1) and Arabidopsis ILI1 binding bHLH1 (IBH1), antagonistically regulate cell elongation in response to brassinosteroid and gibberellin signaling, but the detailed molecular mechanisms by which these factors regulate cell elongatio...

the effect of dry material, glycerol and ratio of water to seed in alyssum homalocarpum films on their thickness, transparency, moisture content, tensile strength, elongation and water vapor permeability was investigated using mixture response surface methods. dry material and glycerol were important factors influencing tensile strength, elongation and water vapor permeability. ratio of water t...

Background and Aims Shoot elongation of arrowhead tubers (Sagittaria pygmaea Miq.) is stimulated by anoxia, ethylene and CO2. The aim of this study was to characterize anoxic elongation by comparison with elongation stimulated by ethylene and CO2. Methods The effects of the inhibitors aminoethoxyvinylglycine (AVG) as an ethylene biosynthesis inhibitor, 1-methylcyclopropene (1-MCP) as a potent i...

Leaf elongation rate (LER) in grasses is dependent on epidermal cell supply (number) and on rate and duration of epidermal cell elongation. Nitrogen (N) fertilization increases LER. Longitudinal sections from two genotypes of tall fescue (Festuca arundinacea Schreb.), which differ by 50% in LER, were used to quantify the effects of N on the components of epidermal cell elongation and on mesophy...

We provide here a molecular movie that captures key aspects of RNA polymerase II initiation and elongation. To create the movie, we combined structural snapshots of the initiation-elongation transition and of elongation, including nucleotide addition, translocation, pausing, proofreading, backtracking, arrest, reactivation, and inhibition. The movie reveals open questions about the mechanism of...