Transgenic tobacco plants activity

Schinkel, H., Schiermeyer, A., Soeur, R Fischer, R and Schillberg, S. (2005). Production of an active recombinant thrombomodulin derivative in transgenic tobacco plants and suspension cells. Transgenic Res. 14(3) 251-259. 

Fig. 1. CAT activities in seeds of transgenic tobacco plants containing hs promoter-CAT constructs. A, Schematic structure of chimaeric genes introduced into tobacco. Details of the construction are described by Schoffl et al. (1989,1991). HSE sequences with the consensus C-GAA-TTC-G are symbolised by boxes the synthetic HSE2 is represented by two overlapping soybean HSEs. The CaMV promoter is a truncated silent version of the 35S promoter, providing only the TATA box and the transcription start site. B, CAT assays were performed as described by Schoffl et al. (1989), using 50 pg protein from seed extracts and 10 jig from leaf extracts. Dry seeds (ds) without imbibition and 20 h imbibed seeds (is), derived from the same plant, were used. Heat treatment (hs) was carried out for 2h at 40 °C prior to protein extraction. Control extracts (c) were prepared from leaves incubated at 25 °C. cm, WC-chloramphenicol acm, acetylated form of cm.

Baumann, G., Raschke, E., Bevan, M. Schoffl, F. (1987). Functional analysis of sequences required for transcriptional activation of a soybean heat shock gene in transgenic tobacco plants. The EMBO Journal 8, 2195-202. 

Fig. 4. Activity retention of Elcd extracted from heat-treated transgenic tobacco plants.

All the treated and untreated transgenic tobacco plant samples were ground and sieved to 40 mesh prior to the Elcd activity assay. Elcd was extracted from the treated and untreated samples as described by Ziegel-hoffer et al. (15). The total protein of each of the extracts was measured by the Bradford (16) method using bovine serum albumin as a standard. Subsequently the appropriate amount of extract containing the same amount of total protein was subjected to the activity assay. 

Transgenic tobacco plants were treated at different temperatures (60-90°C) and at different levels of ammonia (0.5 1, 0.7 1, and 1 1 kg of ammonia kg of dry tobacco sample) to assess the individual effect of each AFEX variable on the Elcd enzymatic activity. All results are the mean of two replicates, and they have been compared with the untreated transgenic tobacco sample. In all the runs the moisture contents are based on the sample dry weight. 

Ziegelhoffer et al. (15) tested the stability of the apoplast-targeted Elcd in transgenic tobacco plants. In their study, the apoplast-targeted Elcd enzyme extracted from tobacco plants, along with the purified microbial Elcd, was subjected to different temperatures (60-90°C) for 10 min. Both enzymes showed similar high thermal stability throughout the experiment. Their results showed that at 60°C up to 95%, at 70°C up to 90%, at 80°C up to 80%, and at 90°C up to 40% of the enzymes activity was retained. However, as seen in Fig. 4, our heat stability test showed sur-... 

The transgenic tobacco samples were AFEX treated under different conditions. These experimental conditions were selected based on the results of our heat and ammonia treatment of transgenic tobacco plants we chose the conditions that showed the highest enzymatic activity retention for Elcd. The results of these experiments are presented in Fig. 6. 

Elcd enzyme showed better survival rates with individual heat or ammonia treatment (up to 67 and 49%, respectively), but the combination of heat and ammonia in AFEX treatment caused a drastic loss in the activity of Elcd. The maximum observed activity retention in AFEX-treated transgenic tobacco plants was only 35% at 60°C, 0.5 1 ammonia loading ratio, and 40% moisture content. Future studies may be able to clarify the mechanistic bases for these observations. 

MCKNIGHT, T.D., BERGEY, D.R., BURNETT, R.J., NESSLER, C.L., Expression of enzymatically active and correctly targeted strictosidine synthase in transgenic tobacco plants. Planta, 1991,185,148-152. 

Some misinterpretations of the NBO performances still occur in the literature. For instance, 5-hydroxyguaiacyl (5-OH-G) units have been tentatively searched for among the NBO products recovered from transgenic tobacco plants deficient in caffeic acid 0-methyltransferase (COMT) activity [31], Studies on COMT-deficient bm3 maize line [32] have shown that the labile 5-OH-G units cannot survive NBO. This situation was anticipated in the pioneering studies of Kuc and Nelson [33], in which they suspected the occurrence of additional as yet undetected lignin units . By contrast and as explained in the next section, thioacidolysis provides an easy determination of 5-OH-G units in native or industrial lignins. 

Perl, M., R. Gafni, and R.N. Beachy Phosphodiesterase activities in transgenic tobacco plants associated with the movement protein of tobacco mosaic virus Theor. Appl. Genet. 84 (1992) 730-734. 

TISSUE SPECIFIC ACTIVITY OF ARABIDOPSIS THALIANA PLASTOCYANIN AND FERREDOXIN PROMOTER ELEMENTS IN TRANSGENIC TOBACCO PLANTS. 

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