A rapid technique for quantitative separation of ribose-methylated nucleosides from base-methylated and non-methylated nucleosides by chromatography on DEAE-cellulose paper in the presence of borate is described. The method has been used as an assay for tRNA ribose methylases from yeast, using under methylated Escherichia coli tRNA as substrate. The main product formed with a partly purified ye...

Fortisan, cellulose triacetate, and NOroxidized cellulose were pyrolyzed in a vacuum in the temperature range 1800 to 465 0 C. Cotton cellulose and cellulose t ri acetate were also pyrolyzed in nitrogen at atmospheric pressure. The tar yields were in the decreasing order from: Cotton, Fortisan, cellulose triacetate, and oxidized cellulose. The other volatiles consisted mainly of acetic acid, ca...

particularly eMcient. The cellulose productiyities of 412 isolates were estimated by cultuTing in two different media under both shaken and static conditions. No correlation between the amounts of cellulose accumulated in shaken and static cultures was observed. Higher cellulose accumlllation was obtained in the shaken cultures using a corn steep liquorlfructose-based medium than a conyentional...

Bacterial cellulose, an exopolysaccharide produced by some bacteria, has unique structural and mechanical properties and is highly pure as compared to plant cellulose. This article presents a critical review of the available information on the bacterial cellulose with special emphasis on its fermentative production and applications. Information on the biosynthetic pathway of bacterial cellulose...

Gluconacetobacter hansenii, a Gram-negative bacterium, produces and secrets highly crystalline cellulose into growth medium, and has long been used as a model system for studying cellulose synthesis in higher plants. Cellulose synthesis involves the formation of β-1,4 glucan chains via the polymerization of glucose units by a multi-enzyme cellulose synthase complex (CSC). These glucan chains as...

Plant cellulose has a hierarchical structure with hemicelluloses and lignin in cell walls, forming natural composites at the nanometer/micrometer levels. The smallest elements next to cellulose molecules are cellulose microfibrils ~3 nm and several microns in width and length, respectively (Fig. 1). Each cellulose microfibril consists of 30-40 fully extended cellulose chains, and forms crystall...

Microtubules determine the orientation of newly formed cellulose microfibrils in expanding cells. There are many hypotheses regarding how the information is transduced across the plasma membrane from microtubules to cellulose microfibrils. However, the molecular mechanisms underlying the co-alignment between microtubules and cellulose microfibrils were not revealed until the recent discovery of...

Dimerization of rhamnogalacturonan-II (RG-II) via boron cross-links contributes to the assembly and biophysical properties of the cell wall. Pure RG-II is efficiently dimerized by boric acid (B(OH)3 ) in vitro only if nonbiological agents for example Pb(2+) are added. By contrast, newly synthesized RG-II domains dimerize very rapidly in vivo. We investigated biological agents that might enable ...

The cortical gel layer of nerve fibers has the properties of a cationexchanger. Hence, this layer can, and actually does, undergo a reversible abrupt structural change when monovalent cations (e.g. Na+) are substituted for the divalent counter-ions (e.g. Ca2+). This structural change brings about a sudden rise in the water content of the layer which in turn produces a large enhancement of catio...

We have synthesized a targeted imaging agent for rheumatoid arthritis based on polysulfated gold nanorods. The CTAB layer on gold nanorods was first replaced with PEG-thiol and then with dendritic polyglycerolsulfate at elevated temperature, which resulted in significantly reduced cytotoxicity compared to polyanionic gold nanorods functionalized by non-covalent approaches. In addition to classi...