Oxidative burst and expression of germin/oxo genes during wounding of ryegrass leaf blades: comparison with senescence of leaf sheaths.

Two bursts of H(2)O(2) production have been detected by in situ 3,3'-diaminobenzidine (DAB) staining after cutting of Lolium perenne L. leaf blades. The first burst, which occurred immediately after wounding was inhibited by Na-diethydithiocarbamate (DIECA), a Cu/Zn-superoxide dismutase (SOD) inhibitor.

Fructans, but not the sucrosyl-galactosides, raffinose and loliose, are affected by drought stress in perennial ryegrass.

The aim of this study was to evaluate the putative role of the sucrosyl-galactosides, loliose [alpha-D-Gal (1,3) alpha-D-Glc (1,2) beta-D-Fru] and raffinose [alpha-D-Gal (1,6) alpha-D-Glc (1,2) beta-D-Fru], in drought tolerance of perennial ryegrass and to compare it with that of fructans. To that end, the loliose biosynthetic pathway was first established and shown to operate by a UDP-Gal: sucrose (Suc) 3-galactosyltransferase, tentatively termed loliose synthase. Drought stress increased neither the concentrations of loliose and raffinose nor the activities of loliose synthase and raffinose synthase (EC 2.

Fate of fructose supplied to leaf sheaths after defoliation of Lolium perenne L.: assessment by 13C-fructose labelling.

The role of fructans from leaf sheaths for the refoliation of Lolium perenne after severe defoliation was assessed by following the fate of (13)C-fructose supplied to leaf sheaths at the time of defoliation. At the end of the 4 h labelling period on defoliated plants, 77% of the (13)C incorporated was still located in leaf sheaths. Only 4% and 0.

Shemin pathway and peroxidase deficiency in a fully habituated and fully heterotrophic non-organogenic sugarbeet callus: an adaptative strategy or the consequence of modified hormonal balances and sensitivities in these cancerous cells? A review and reassessment.

There are many arguments for considering a specific fully habituated (auxin and cytokinin-independent) and fully heterotrophic non-organogenic (HNO) sugarbeet callus cell line as terminating a neoplastic progression, and thus to be made of cancerous cells. The similarities with animal tumour and cancer cells are recalled. All types of habituated tissues examined in the literature share at least three common biochemical characteristics: low apparent peroxidase activity, high content of polyamines (PAs) and low production of ethylene.

Molecular cloning of the 5-aminolevulinic acid dehydratase gene from Rhodobacter sphaeroides.

A hemB mutant of Escherichia coli was used to clone the gene encoding 5-aminolevulinic acid dehydratase from Rhodobacter sphaeroides after physiological complementation of the mutation. A 2.9-kb DNA fragment was obtained and cloned in both orientations into the unique PstI restriction site of pUC19.

Inhibitory effect of gabaculine on 5-aminolevulinate dehydratase activity in radish seedlings.

We have compared the activity of 5-aminolevulinate dehydratase (5-ALAD) with the amount of protein detected by specific antibodies in rocket immunoelectrophoresis. Parallel kinetic evolutions of enzymic activity and amount of antigen were observed in radish (Raphanus sativus L.) cotyledons, both in complete darkness or under standard far red light involving phytochrome.

Production of monospecific antisera by immunization with precipitin line leads to misinterpretation of immunoblot.

Immunoblotting displays an artifact in the preparation of monospecific antibodies from immunocomplexes cut out of line immunoelectrophoresis. Agarose induces the formation of antibodies towards a 68 KDa protein which is contained in commercial agarose.

Lag-phases in phytochrome-mediated enzyme synthesis (PAL).

In experiments with the mustard seedling (Sinapis alba L.) it was confirmed that in the case of "secondary irradiation" induction of PAL by phytochrome is a very rapid process. The lag-phase after the onset of light is too brief to be detected.