[Identification of Two GLOBOSA-like MADS-box Genes in Tea Plant (Camellia sinensis [L.] O. Kuntze)].

Tea plant (Camellia sinensis [L.] O. Kuntze) is a woody crop of high economic importance worldwide; however, information on the molecular mechanisms underlying the regulation of flower development in this species is limited. In the present study, two GLOBOSA (GLO) -like MADS-box genes, CsGLO1 and CsGLO2, were isolated from C. sinensis 'Ziyangzhong' and were characterized to elucidate their roles in flower development. We found that CsGLOl and CsGLO2 are nuclear-localized transcription factors without transactivation ability but with a robust interaction. They have similar patterns of expression, both mainly restricted to petals and stamens. Moreover, ectopic expression of either CsGLO1 or CsGLO2 in Arabidopsis thaliana resulted in a partial conversion of sepals to petals, suggesting full GLOBOSA functional activity. Our results indicate that CsGLO1 and CsGLO2 paralogs might redundantly contribute to petal and stamen, providing the first insight into their role in tea plant flower development.

Mechanisms of L-DOPA-induced cytotoxicity in rat adrenal pheochromocytoma cells: implication of oxidative stress-related kinases and cyclic AMP.

L-DOPA therapy for Parkinson's disease has a double-edge effect on nigrostriatal dopaminergic neurons: L-DOPA increases the intracellular level of dopamine, but it induces neuron cytotoxicity in a concentration-dependent manner. To investigate the molecular signaling mechanisms that underlie the concentration-dependent effects of L-DOPA on cell viability, the activities of mitogen-activated protein kinases (MAPKs) and apoptotic enzymes were measured in rat adrenal pheochromocytoma (PC12) cells in the presence of a low concentration (20 muM) and high concentrations (100-200 muM) of L-DOPA. At the low concentration, L-DOPA was not cytotoxic and its presence increased the activities of extracellular signal-regulated kinase (ERK)1/2, p38 MAPK, BadSer112, Bcl-2, and caspase-12. At the high concentrations, L-DOPA was cytotoxic and stimulated the activities of ERK1/2, p38 MAPK, c-Jun N-terminal kinase (JNK)1/2, BadSer155, caspase-12 and caspase-3. The increased levels of ERK1/2 and BadSer155 in the presence of high concentrations of L-DOPA did not protect against L-DOPA-mediated cytotoxicity. In addition, the levels of L-type Ca(2+) channel-sensitive intracellular cyclic AMP (cAMP) and Ca(2+) were elevated in the presence of L-DOPA, and the increase in the levels of intracellular cAMP may also play a role in cellular viability, since cAMP levels and cytotoxicity increased in parallel with L-DOPA concentrations and the addition of forskolin in the medium increased cytotoxicity in a concentration-dependent manner. These results suggest that, at a low and non-toxic concentration, L-DOPA may promote cell survival by increasing the activities of ERK1/2, BadSer112 and Bcl-2, while, at high concentrations, L-DOPA activates the caspase-3 cell death enzyme through the JNK1/2 and p38 MAPK signaling pathways as well as endoplasmic reticulum stress that activates caspase-12. Intracellular cAMP levels may also play a role here. The results may lead to an effective therapy for Parkinson's disease.