Effects of Oxidative Stress and Culture Conditions on the Levels of Defensive Enzymes Against Oxidative Stress in Chlamydomonas reinhardtii

Eukaryotic cells under stress repress translation and localize these messenger RNAs (mRNAs) to cytoplasmic RNA granules. We show that specific stress stimuli induce the assembly of RNA granules in an organelle with bacterial ancestry, the chloroplast of Chlamydomonas reinhardtii. These chloroplast stress granules (cpSGs) form during oxidative stress and disassemble during recovery from stress. Like mammalian stress granules, cpSGs contain poly(A)-binding protein and the small, but not the large, ribosomal subunit. In addition, mRNAs are in continuous flux between polysomes and cpSGs during stress. Localization of cpSGs within the pyrenoid reveals that this chloroplast compartment functions in this stress response. The large subunit of ribulosebisphosphate carboxylase/oxygenase also assembles into cpSGs and is known to bind mRNAs during oxidative stress, raising the possibility that it plays a role in cpSG assembly. This discovery within such an organelle suggests that mRNA localization to granules during stress is a more general phenomenon than currently realized.

Download Full-text

Characterization of the alternative oxidase of Chlamydomonas reinhardtii in response to oxidative stress and a shift in nitrogen source

Physiologia Plantarum ◽

10.1111/j.1399-3054.2006.00643.x ◽

2006 ◽

Vol 127 (1) ◽

pp. 74-86 ◽

Cited By ~ 20

Author(s):

Teresa A. Molen ◽

Dominic Rosso ◽

Sarah Piercy ◽

Denis P. Maxwell

Keyword(s):

Oxidative Stress ◽

Chlamydomonas Reinhardtii ◽

Nitrogen Source ◽

Alternative Oxidase

Download Full-text

Effect of Chromium on Antioxidant Potential ofCatharanthus roseusVarieties and Production of Their Anticancer Alkaloids: Vincristine and Vinblastine

BioMed Research International ◽

10.1155/2014/934182 ◽

2014 ◽

Vol 2014 ◽

pp. 1-10 ◽

Cited By ~ 27

Author(s):

Vartika Rai ◽

Pramod Kumar Tandon ◽

Sayyada Khatoon

Keyword(s):

Oxidative Stress ◽

Indole Alkaloids ◽

Culture Conditions ◽

Antioxidant Potential ◽

Terpenoid Indole Alkaloids ◽

Protective Mechanisms ◽

Important Place ◽

Antioxidant Responses ◽

Active Constituents ◽

Pot Culture

Catharanthus roseus(L.) G. Don, a medicinal plant, has a very important place in the traditional as well as modern pharmaceutical industry. Two common varieties of this plantroseaandalbaare named so because of pink and white coloured flowers, respectively. This plant comprises of about 130 terpenoid indole alkaloids and two of them, vincristine and vinblastine, are common anticancer drugs. The effect of chromium (Cr) on enzymatic and non-enzymatic antioxidant components and on secondary metabolites vincristine and vinblastine was studied under pot culture conditions of both varieties ofC. roseus. Antioxidant responses of these varieties were analyzed under 0, 10, 50, and 100 μM chromium (Cr) level in order to investigate the plant’s protective mechanisms against Cr induced oxidative stress. The results indicated that Cr affects all the studied parameters and decreases growth performance. However, vincristine and vinblastine contents were increased under Cr stress. Results are quite encouraging, as this plant shows good antioxidant potential and increased the level of active constituents under Cr stress.

Download Full-text