Tobacco callus

E. coli 0157 H7 Intimin epitope Tobacco callus Mucosally immunogenic in mice when primed parenterally and boosted orally. Mice immunized parenterally and orally boosted showed reduced duration of colonization upon challenge. 92... 

Todd reported that the respiration of pinto bean leaves was stimulated by exposure to ozone (at 4 ppm for 40 min). The first measurements were 4 h after the ozone exposure. The respiration rate later declined to the control value. In all cases, increased respiration correlated well with visible injury. MacdowalP confirmed these results, but made an additional observation during the first hour after ozone exposure (at 0.7 ppm for 1 h), and before visible symptoms appeared, respiration was inhibited. The increase in respiration took place only later, when visible symptoms appeared. Dugger and Palmer" reported an increase in respiration in lemon leaf tissue after 5 days of exposure to ozone at 0.15-0.25 ppm for 8 h/day. They reported no morphologic changes at that time. Anderson and Taylor S found that ozone induced carbon dioxide evolution in tobacco callus tissue. The threshold for evolution was about 0.1 ppm for 2 h in the sensitive Bel W,. The ozone concentration required for maximal carbon dioxide evolution was about twice as much in the more resistant cultivar. Formation of roots decreased sensitivity. 

Anderson, W. C., and O. C. Taylor. Ozone induced carbon dioxide evolutioo in tobacco callus cultures. Physiol. PUnt. 28 419-423, 1973. 

NT386 Kaul, K., and P. S. Sabbarwal. Kine-tin induced changes in delta-aminolevulinic acid dehydratase of tobacco callus. Plant Physiol 174 54 644. NT398... 

NT432 Lance, B., R. C. Durley, D. M. Rreid, T. A. Thorpe, and R. P. Pharis. Metabolism of ( H)gibberellin A-20 in light and dark-grown tobacco callus cultures. Plant Physiol 1976 58 387. 

NT443 Hodges, L. C., G. W. Robinson, and K. Green. Extract of tobacco callus with antiglaucoma activity. Phytother Res 1991 5(1) 15-18. 

Galston. Modified alkaloid pattern in developing tobacco callus. Plant Sci 1985 38(3) 207-212. NT510... 

NT564 Grady, K. L., and J. A. Bassham. 1-Aminocyclopropane-1 -carboxylic acid concentrations in shoot-forming and non-shoot forming tobacco callus NT575 cultures. Plant Physiol 1982 70 ... 

Reversal of inhibition caused by 14 was assayed quantitively using compound 3, 6-benzylaminopurine and diphenylurea, the latter two of which are about 1/10 and 1/1000 as active as 3, respectively, in promoting the growth of tobacco callus (13,81). Not unexpectedly, 6-benzylaminopurine was only about 1/3 as potent as 3 in reversing inhibition by )L4 and diphenylurea was only 1/500 as effective. Thus, the ability of the cytokinins to reverse inhibition paralleled their activity as cytokinins, consistent with the... 

Figure 2. The effect on the fresh weight yield of tobacco callus of 6-benzylamino-purine (2) and 3-methyl-7-(3-methylbutylamino)pijrazolo[4,3-d]pyrimidine (14)...

In addition to the substituted pyrrolo[2,3-d]pyrimidines discussed above, several 4-substituted-7-(8-D-ribofuranosyl)pyrrolo-[2,3-d]pyrimidines were also prepared and tested in the tobacco bioassay (85,86) most of the analogs inhibited the growth of tobacco callus cultured on kinetin. It is not clear from the published data, however, to what extent inhibition could be reversed by higher concentrations of kinetin. In addition, the analog... 

A ribonucleoside with properties very similar to those of cis-ribosylzeatin contained some 40% of the total tracer incorporated into t-RNA from MVA by preparations of tobacco callus 396 the remainder of the tracer was accounted for by non-specific incorporation of products from degradative processes. 

D, Induce PR-protelns In tobacco callus or In Intact tobacco leaves (1821. Kinetin (1811 and gibberelllc acid (1831 are also PR-proteIn Inducers. 

IPA Transformed tobacco callus cultures were cultured on BR-... 

Table I Water content of transformed tobacco callus-cultures grown on brassinosteroid-containing medium for 3 weeks. The brassinosteroid employed (BR-1) is a synthetic 225,235,245-analog of the naturally occurring brassinolide. The concentration of BR-1 was varied from IO 10 M to KT6 M CV <5%...

Table IV Comparison of the effects of ecdyson and BR-1 on growth of transformed tobacco callus-cultures. The concentrations of hormones were varied as indicated. Culture period 3 weeks. Each value represents the mean of 5 replicates. CV <5%...

Two compounds common in plant metabolism are believed to be precursors of isoprenoid cytokinins in plants adenosine-5 -monophosphate (AMP) and A -isopentenylpyrophos-phate (iPP). As a final product of the mevalonate pathway, the latter substance serves also as a precursor for a wide spectrum of metabolites including some other plant hormones, as abscisic acid, gibberellins and brassinosteroids. The hypothetical scheme of reactions resulting in the formation of iPA, Z and DHZ is given in Fig. 2. The enzyme of entry into isoprenoid cytokinin formation is A -isopentenylpyrophosphate 5 -AMP-A -iso-pentenyltransferase (EC 2.5.1.8, trivially named cytokinin synthetase ). This enzyme activity was first detected in a cell-free preparation from the slime mould Dictyostelium discoideum [7,8]. Later the enzyme from higher plants (cytokinin-independent tobacco callus [9,10] and immature Zea mays kernels [11]) was described and the data were recently summarised in [12], The enzyme is very specific as far as the substrate is concerned [13,14] only the nucleotide AMP can be converted and only iPP (with a double bond in A position) may function as a side chain donor. 

Brossard, D. The influence of kinetin on formation and ploidy levels of buds arising from N. tabacum pith tissue grown in vitw, Z. Pflanzenphysiol. 78 (1976) 323-333. Brown, D.C.W. and T.A. Thorpe Adenosine phosphate and nicotinamide adenine dinucleotide pool sizes during shoot initiation in tobacco callus Plant Physiol. 65 (1980) 587-590. 

Capsidol A phytoalexin produced by tobacco callus tissues Plant Physiol. (1978) Suppl. 318. 

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