Selenium-induced oxidative stress in coffee cell suspension cultures

2007 ◽  
Vol 34 (5) ◽  
pp. 449 ◽  
Author(s):  
Rui A. Gomes-Junior ◽  
Priscila L. Gratão ◽  
Salete A. Gaziola ◽  
Paulo Mazzafera ◽  
Peter J. Lea ◽  
...  

Selenium (Se) is an essential element for humans and animals that is required for key antioxidant reactions, but can be toxic at high concentrations. We have investigated the effect of Se in the form of selenite on coffee cell suspension cultures over a 12-day period. The antioxidant defence systems were induced in coffee cells grown in the presence of 0.05 and 0.5 mm sodium selenite (Na2SeO3). Lipid peroxidation and alterations in antioxidant enzymes were the main responses observed, including a severe reduction in ascorbate peroxidase activity, even at 0.05 mm sodium selenite. Ten superoxide dismutase (SOD) isoenzymes were detected and the two major Mn-SOD isoenzymes (bands V and VI) responded more to 0.05 mm selenite. SOD band V exhibited a general decrease in activity after 12 h of treatment with 0.05 mm selenite, whereas band VI exhibited the opposite behavior and increased in activity. An extra isoenzyme of glutathione reductase (GR) was induced in the presence of selenite, which confirmed our previous results obtained with Cd and Ni indicating that this GR isoenzyme may have the potential to be a marker for oxidative stress in coffee.

1980 ◽  
Vol 35 (7-8) ◽  
pp. 551-556 ◽  
Author(s):  
K.-H. Knobloch ◽  
J. Berlin

Cell suspension cultures of Catharanthus roseus have been subjected to various media condi­tions in order to stimulate the formation of indole alkaloids. High ajmalicine contents (up to 0.5 mg/g cell fresh weight) were achieved by transferring 2-week-old cell suspensions to a 10-fold volume of a 8% sucrose solution. The alkaloid accumulation started two days after the transfer and reached a plateau after ten days. Furthermore an enhanced level of phenolic compounds was found, whereas growth of the culture was low. The accumulation of both, alkaloids and poly­phenols was stimulated by high concentrations of sucrose and low concentrations of nitrogen con­taining salts and phosphate. When these minerals were added to the sucrose solution in con­centrations commonly used for cell culture media, the accumulation of alkaloids and phenolic compounds was largely suppressed.


1979 ◽  
Vol 34 (11) ◽  
pp. 914-922 ◽  
Author(s):  
E. Keller ◽  
J. Eberspächer ◽  
F. Lingens

Abstract Metabolism of chloridazon, the active ingredient of the herbicide Pyramin, was studied in cell suspension cultures of Beta vulgaris (sugar beet), Papaver bracteatum (poppy), Phaseolus aureus (mung bean), Glycine max (soya bean), Nicotiana tabacum (tobacco), and Petroselinum hortense (parsley). Metabolism of the analgetical and antipyretical drug antipyrin (phenazon) was also investigated. In Beta vulgaris and in Papaver bracteatum small amounts of both compounds are hydroxylated, the main quantity remaining unmetabolized. In Beta vulgaris chloridazon is converted to p-hydroxy- chloridazon, whereas antipyrin yields three different compounds, namely p-hydroxyantipyrin, hydroxymethylantipyrin and a further hydroxyantipyrin, which was identified as o- or m-hydroxy- antipyrin. Cell suspension cultures of Papaver bracteatum hydroxylate chloridazon to p- and m- hydroxychloridazon, respectively, and antipyrin to p-hydroxyantipyrin and hydroxymethylantipyrin respectively. The metabolites, with exception of o- or m-hydroxyantipyrin, were identified by spectroscopic methods. The structure of the latter metabolite was established by comparing Up­values of the metabolite and the compound synthetically available. Metabolism in sugar beet and poppy cultures is similar to metabolism in mammals rather than in bacteria. Cell suspensions of chloridazon-insensitive sugar beet and of chloridazon-sensitive poppy are severely inhibited in growth by chloridazon, whereas antipyrin, even when applied in high concentrations, does not induce growth inhibition. In soya bean, mung bean, tobacco, and parsley neither chloridazon nor antipyrin were found to be metabolized.


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