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Goldberg, R., Liberman, M., Mathieu, C, Pierron, M. and Catesson, A. M. 1987. Development of epidermal cell wall peroxidases along the mung bean hypocotyl: possible involvement in the cell wall stiffening process.—J. exp. Bot. 38: 1378–1390. Ultrastructural investigation showed that in the epidermis of mung bean hypocotyls, cell wall peroxidatic activities could be detected mainly below the maximal elongation zone. In the epidermis the peroxidatic activities were preferentially located in the radial cell walls. Cell wall peroxidases were then isolated from epidermal strips and further characterized. The possible presence of a H2O2-generating system in the epidermis of mung bean hypocotyls was also investigated. When whole segments were processed for electron microscopy, H2O2 could be detected cytochemically in the cell walls with the CeCl3 technique. A positive reaction was obtained in the same location when specimens were incubated in a 3-3′-diaminobenzidine medium for peroxidases in which H2O2 was replaced by its possible precursors (NADH or NAD + malate). However, isolated epidermal cell walls could not generate H2O2 at the expense of NADH although they were able to oxidize the reduced nicotinamide-adenine-dinucleotide. The possible relationships between peroxidase activities, H2O2, and Ca2+ ions are discussed with respect to their involvement in the cell wall stiffening process.

Evaluates the Sony XV-T33 Video Sketch Titler, a title generator for video enthusiasts. Design; Plastic membrane touchpad and stylus; Use as a video sketchpad; Example of use, from raw footage to finished output; Custom lettering; Graphics available; Sony's address and telephone number.

Evaluates NewTek Inc.'s Video Toaster, a postproduction hardware/software system that plugs into a Commodore Amiga 2000-series computer. Special-effects generation (SEG); Character generation (CG), 3-dimensional animation and other features; Additional programs such as Toaster Character Generator, Lightwave Modeler and Toaster Paint; NewTek Inc.'s address and telephone number.

Evaluates the Sony stereo television tuner, Model ST-72TV. Features; Test results; Comments; Laboratory measurements. INSET: Summary..

Gives a first-person evaluation of Macromind's MediaMaker, a post-production software package for the Apple Macintosh computer. MediaMaker can combine video footage with animation, text, graphics and music. Video Logic DVA 4000 input card; Concept behind MediaMaker; How to use MediaMaker; Macromind's `Director' multimedia software; Editing; Animated titles.

Evaluates the Canon L1 camcorder, a new Hi8 camcorder. Flexibility; Many features; 15X zoom lens with macro capability; Author's comments; Manufacturer's address and telephone number.