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Abstract. Loss-of-function and gain-of-function approaches were utilised to detect the physiological importance of glycerol biosynthesis during salt stress and the role of glycerol in conferring salt tolerance in Arabidopsis. The salt stress experiment involved wild type (WT) and transgenic Arabidopsis overexpressing the yeast GPD1 gene (analogue of Arabidopsis GLY1 gene). The experiment also involved the Arabidopsis T-DNA insertion mutants gly1 (for suppression of glycerol 3-phosphate dehydrogenase or G3PDH), gli1 (for suppression of glycerol kinase or GK), and act1 (for suppression of G3P acyltransferase or GPAT). We evaluated salt tolerance levels, in conjunction with glycerol and glycerol 3-phosphate (G3P) levels and activities of six enzymes (G3PDH, ADH (alcohol dehydrogenase), ALDH (aldehyde dehydrogenase), GK, G3PP (G3P phosphatase) and GLYDH (glycerol dehydrogenase)) involved in the glycerol pathway. The GPD1 gene was used to overexpress G3PDH, a cytosolic NAD + -dependent key enzyme of cellular glycerol biosynthesis essential for growth of cells under abiotic stresses. T 2 GPD1-transgenic plants and those of the two mutants gli1 and act1 showed enhanced salt tolerance during different growth stages as compared with the WT and gly1 mutant plants. These results indicate that the participation of glycerol, rather than G3P, in salt tolerance in Arabidopsis. The results also indicate that the gradual increase in glycerol levels in T 2 GPD1-transgenic, and gli1 and act1 mutant plants as NaCl level increases whereas they dropped at 200 mM NaCl. However, the activities of the G3PDH, GK, G3PP and GLYDH at 150 and 200 mM NaCl were not significantly different. We hypothesise that mechanism(s) of glycerol retention/efflux in the cell are affected at 200 mM NaCl in Arabidopsis.

Thymoquinone (TQ) is a major constituent of Nigella sativa oil with reported anti-oxidative activity and anti-inflammatory activity in animal cells. It also inhibits proliferation and induces programmed cell death (apoptosis) in human skin cancer cells. The present study sought to detect the influence of TQ on dividing cells of three plant systems and on expression of Bcl2-associated athanogene-like (BAG-like) genes that might be involved during the process of cell death. BAG genes are known for the regulation of diverse physiological processes in animals, including apoptosis, tumorigenesis, stress responses, and cell division. Synthetic TQ at 0.1 mg/mL greatly reduced wheat seed germination rate, whereas 0.2 mg/mL completely inhibited germination. An Evans blue assay revealed moderate cell death in the meristematic zone of Glycine max roots after 1 h of TQ treatment (0.2 mg/mL), with severe cell death occurring in this zone after 2 h of treatment. Light microscopy of TQ-treated (0.2 mg/mL) onion hairy root tips for 1 h revealed anti-mitotic activity and also cell death-associated changes, including nuclear membrane disruption and nuclear fragmentation. Transmission electron microscopy of TQ-treated cells (0.2 mg/ mL) for 1 h revealed shrinkage of the plasma membrane, leakage of cell lysate, degradation of cell walls, enlargement of vacuoles and condensation of nuclei. Expression of one BAGlike gene, previously associated with cell death, was induced 20 min after TQ treatment in Glycine max root tip cells. Thus, TQ has multiple effects, including cell death, on dividing plant cells and plants may serve as a useful system to further investigate the mechanisms underlying the response of eukaryotic cells to TQ.ß 2013 Published by Elsevier Masson SAS on behalf of Acade ´mie des sciences.

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On top of the scenic escarpment road of Al Hada, people regularly feed baboons and members of a large troop of Papio hamadryas developed commensal habits, waiting for handouts beside the ro ad. Alarmed by the increasing baboon number, local authorities wish to control the troop 's enlargement. A direct solution to prevent the troop's growth would be to forbid people to feed baboons. However, both the sufficiency of natural vegetation and the ability of the troop to return to feeding on natural resources is uncertain. The response of baboons to a reduced provisioning was studied when the road was closed for maintenance during winter. We compared the relative share of natural vegetation an d handouts in the troop's diet along the year and monitored range use in relation to food availability. The main effects of handout reduction were the enlargement of daily range combined with relocation and diversification of sleeping sites, the troop splitting into small sleeping groups. Baboons switched easily to a natural diet. Numerous plant species were consumed, but the Juniper species typical of these elevations were the most commonly selected. The results show the feasability and efficiency of the reduction of food provision in managing such commensal groups living partially from human handouts.