Stress osmotic

In making the reasonable assumption that browser diets should have remained consistent through time, it was also assumed that C7 C ratios of their C3 foliage diets would not have changed. This is not the case environmental parameters such as aridity, osmotic stress, temperature, pCOi and irra-diance have predictable effects on ratios of C3 plants (summarized in... 

Tsvetkova, N., Golyasnaya, N. Induction of SOS-response in Escherichia coli under conditions of osmotic stress and in the presence of N-methyl-N -nitro-N-... 

Jones, H.G. (1973). Photosynthesis by thin leaf slices in solution. II. Osmotic stress and its effects on photosynthesis. Australian Journal of Biological Sciences, 26, 25-33. 

Kaiser, W.M. (1982). Correlation between changes in photosynthetic activity and changes in total protoplast volume in leaf tissue from hygro-, meso-, and xer-ophytes under osmotic stress. Planta, 154, 538-45. 

Ward, D.A. Drake, B.G. (1988). Osmotic stress temporarily reverses the inhibitions of photosynthesis and stomatal conductance by abscisic acid - evidence that abscisic acid induces a localized closure of stomata in intact, detached leaves. Journal of Experimental Botany, 39, 147-55. 

Cells selected for tolerance to water stress have been demonstrated in a number of plant species (Handa et al., 1983 Heyser Nabors, 1981 Stavarek Rains, 1984b). High molecular weight PEG is commonly used to induce water deficits (Hasegawa et al., 1984). This provides an opportunity to evaluate intracellular osmotic adjustment of plants exposed to water stress. If information is desired on the effect of specific osmotic substances on cellular adjustment to osmotic stress PEG can be used as an independent osmotic regulator and/or in combination with an absorbable osmoticum. In these situations the interaction of osmoticum produced by the cell with the osmoticum absorbed by the cell can be evaluated. 

Growth characteristics of cells exposed to water stress mimic some of the structural responses of organised plant tissues. A frequently observed response of plants exposed to water stress is a reduction in cell size (Cutler, Rains Loomis, 1977). This cellular phenomenon was observed in tomato cells stressed with PEG (Handa et al., 1983). Concomitantly with a decrease in cell size with increasing osmotic stress was a reduction in fresh weight. In contrast the dry weight was not affected. 

Koch, G., Wells, R. Grisebach, H. (1987). Differential induction of enzyme in soybean cell cultures by elictor or osmotic stress. Planta, 171, 519-24. 

From a shear sensitivity perspective, it is particularly interesting to note that the OB has also been observed to occur in response to other, non-pathogenic stimuli, including wounding [176], agitation [177-180], pressure [181,182] and osmotic stress [180,183]. Relevant studies are summarized in Table 4. 

Tobacco (Nicotiana tabacum) osmotic stress, baffled agitation scopoletin fluorescence [180]... 

Soybean (Glycine max) direct apphcation of pressure to slide-moimted cells osmotic stress pyranine fluorescence 2, 7 -dichlorofluorescein diacetate [183]... 

Interactions with neutral and anionic polymers (osmotic stress)... 

E. Structures Based on DNA Condensation Under Osmotic Stress... 

Similar to the sitnation with DNA structures formed under osmotic stress, DNA strands in cation-condensed bundles were found to be hexagonally packed and to possess liqnid crystalline order. For example, spermine and spermidine-condensed samples were fonnd to contain a cholesteric phase [70]. Surprisingly, DNA condensed with (Co(NH3)6) failed to exhibit a liquid crystalline ordering [47]. 

A second family of MAPKs is referred to as stress-activated protein kinases (SAPKs) [3,14,15]. This includes JNKs, or Jun kinases, named originally for their phosphorylation of the transcription factor c-Jun. SAPKs were first identified in peripheral tissues on the basis of their activation in response to cellular forms of stress, which include X-ray irradiation and osmotic stress. More recently, they have been demonstrated to be activated in brain by several cytokines as well as by synaptic activity [16]. As shown in Figure 23-3, SAPKs are activated by SAPK kinases (SEKs), which are in turn activated by SEK kinases. The Ras-like small G proteins implicated in SEK kinase activation are Rac and Cdc-42. In this case, it appears that Rac/Cdc-42 triggers activation of SEK kinase by stimulating its phosphorylation by still another protein kinase termed p21-activated kinase (PAK). Thus, PAK can be considered a MAPK kinase kinase kinase, which is analogous to the cascade of protein kinases found in yeast (Fig. 23-4). 

McKenney, C.L., Jr. and D.B. Hamaker. 1984. Effects of fenvalerate on larval development of Palaemonetes pugio (Holthuis) and on larval metabolism during osmotic stress. Aquat. Toxicol. 5 343-355. 

Graney, R.L. and J.P. Giesy, Jr. 1987. The effect of short-term exposure to pentachlorophenol and osmotic stress on the free amino acid pool of the freshwater amphipod Gammarus pseudolimnaeus Bousfield. Arch. Environ. Contam. Toxicol. 16 167-176. 

Rastogi, N.K., Angersbach, A., and Knorr, D. 2000b. Synergistic effect of high hydrostatic pressure pre-treatment and osmotic stress on mass transfer during osmotic dehydration. J. Food Engineer. 45, 25-31. 

Spiess, W.E.L., Behsnilian, D., Ferrando, M., Gaiser, M., Gartner, U., Hasch, M., Mayer-Miebach, E., Rathjen, A., and Walz, E. 2002. Mass transfer and related phenomena in plant tissue during heat treatment and osmotic stress. In Engineering and Food for the 21st Century (J. Welti-Chanes, G.V. Barbosa-Canovas, and J.M. Aguilera, eds), pp. 177-191. CRC Press, Boca Raton, FL. 

Dummermuth A, Karsten U, Fisch K, Konig G, Wiencke C (2003) Responses of marine macroalgae to hydrogen-peroxide stress. J Exp Mar Biol Ecol 289 103-121 Edwards DM, Reed RH, Chudek JA, Foster R, Stewart WDP (1987) Organic solute accumulation in osmotically-stressed Enteromorpha intestinalis. Mar Biol 95 583-592 Edwards DM, Reed RH, Stewart WDP (1988) Osmoacclimation in Enteromorpha intestinalis. ... 

Expression of ERF3 and ERF4 from sugarcane and cotton, respectively, rapidly increases response to exogenous ethylene and ABA, salt, cold, and drought, whereas their overexpression in transgenic plants enhances tolerance to drought and osmotic stress. ... 

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