Ethylene wound

ST-ACS2 potato tuber 12hr ethylene, wounding 80... 

The film tube is collapsed within a V-shaped frame of rollers and is nipped at the end of the frame to trap the air within the bubble. The nip roUs also draw the film away from the die. The draw rate is controlled to balance the physical properties with the transverse properties achieved by the blow draw ratio. The tube may be wound as such or may be sHt and wound as a single-film layer onto one or more roUs. The tube may also be direcdy processed into bags. The blown film method is used principally to produce polyethylene film. It has occasionally been used for polypropylene, poly(ethylene terephthalate), vinyls, nylon, and other polymers. 

Paraffin gauze dressing Perforated film absorbent dressing Polyurethane foam Burns, scaids, grafts Postoperative wounds Burns, ulcers, grafts. Any combination of dry heat, gamma-radiation and ethylene oxide... 

Elastic adhesive dressing Protective wound dressing Ethylene oxide or... 

Worm end products, 18 646 Worsted wool-processing system, 26 383-384, 385-386 Worsted yarn, 11 178 Wort, 3 563, 564, 574, 575, 583 separation, 3 578-579 Wound closure, suture size and, 24 216 Wound closure biomaterials, 24 205. See also Sutures Wound dressings cotton smart, 3 31 ethylene oxide polymers in, 10 687 hydrogels in, 13 751-752 Woven fabrics, 11 178 dyeing, 9 170-171 Woven flax fibers, 11 594 Woven plastic bags, 18 12 Wovens... 

Plants respond to the mechanical or insect herbivore damage of their tissues." During herbivorous attacks, some plants emit a specific blend of volatiles, which may result in defense responses retarding development of the herbivores or attraction of herbivore enemies to feed upon them. In lima bean leaves, the spider mite-induced volatiles, as well as infestation and artificial wounding, activate the ethylene and JA signaling pathways. ... 

The most recent discoveries in the methionine to ethylene pathway are the demonstration of S-adenosylmethionine as the intermediate and the existence of the multigene family of ACC synthases that convert S-adenosylmethionine to ACC (for review see Kende, 1993). The expression of the different genes in different tissues is determined by different stimuli such as ripening, tissue wounding or the status of cell growth responses. The isolation of the oxidase enzyme that converts ACC to liberate the free ethylene molecule in vitro (Ververidis and John, 1991) was another breakthrough, particularly because for many years it was thought that the enzymes concerned would operate only on an intact membrane system in vivo. 

Fig. 1. Ethylene biosynthesis. The numbered enzymes are (1) methionine adenosyltransferase, (2) ACC (l-aminocyclopropane-l-carboxylic acid) synthase, (3) ethylene forming enzyme (EFE), (4) 5 -methylthio-adenosine nucleosidase, (5) 5 -methylthioribose kinase. Regulation of the synthesis of ACC synthase and EFE are important steps in the control of ethylene production. ACC synthase requires pyridoxal phosphate and is inhibited by aminoethoxy vinyl glycine EFE requires 02 and is inhibited under anaerobic conditions. Synthesis of both ACC synthase and EFE is stimulated during ripening, senescence, abscission, following mechanical wounding, and treatment with auxins.

Ethylene plays an important role in a number of plant developmental processes, including senescence and abscission of leaves and flowers, responses to wounding, and the ripening of climacteric fruits (Abeles, 1973). In each case ethylene is produced from methionine (Fig. 1). The two enzymes specific to the pathway, ACC synthase and ethylene forming enzyme, increase in activity in response to wounding and during ripening,... 

Fig. 4. Ethylene production by wounded leaves and ripening fruit of normal tomato plants and those transformed with EFE (pTOM 13) antisense genes. A, Ethylene production by wounded leaves of plants with none ( ), 1 (O), or 2 ( ) antisense genes B, ethylene production by ripening fruit from plants with none ( ), 1 (O), or 2 ( ) antisense genes (after Hamilton et al., 1990).

Fig. 5. Activity of ethylene forming enzyme (ACC oxidase) in wounded leaves of transgenic tomato plants containing 0, 1, or 2 pTOM 13 anti-sense genes (after Hamilton et at., 1990).

Plants under water stress are known to produce increased amounts of ethylene, show a rise in ABA and a decline in endogenous cytokinins (52,53). Other plant hormones are also probably involved in the response to water stress and other stress and wounding actions. The surge of ethylene production upon stress may therefore represent a response to a disturbance of the hormonal balance in tissues. The dampened oscillation curve for wound ethylene production may reflect the dynamic return of the disturbed hormonal system to a proper hormonal balance under the new tissue conditions, and thus may also reflect a healing phenomenon. 

Figure 6. Profile of ethylene production by wounded stems of etiolated pea seedlings. The profile shows kinetic changes suggesting dampened oscillation (from Saltveit and Dilley (50))...

These flows were guided into a wound delay tube for reaction with ethylene glycol/ water (60/40 wt%) and hydrogen [324,326]. Efficient mass transfer in a kinetically controlled manner was achieved by the large specific gas-liquid interfaces of the foams of up to 50000m2/m3. 

---