Short photoperiod induces dormancy in Lotus (Nelumbo nucifera). (1/22)

BACKGROUND AND AIMS: Lotus (Nelumbo nucifera) has been cultivated as an ornamental and food plant in Japan for more than 1000 years. As large areas are required for its cultivation (approximately 2 m2 per plant), physiological research, such as into the effect of environmental factors on dormancy, has not been well studied until recently. In this paper, seedlings were used to examine environmental factors affecting dormancy induction. METHODS: In a first experiment, seeds were sown from 6 April to 6 October at 2-month intervals, and cultivated for 2 months in an unheated greenhouse. In a second experiment, seeds were prepared for germination on 16 November and 16 May and the seedlings were grown at 25 or 30 degrees C under natural daylength in phytotron growth rooms. After 1 month, the seedlings were cultivated at 20, 25 or 30 degrees C for a further month. The number of leaves and rhizome branches on the main stem were counted, and growth of rhizomes on the main stem was calculated using a rhizome enlargement index (= maximum internode diameter/internode length) after 2 months of culture in both experiments. KEY RESULTS: Rhizomes elongated without enlargement when the seeds were sown in April and June. Sowing the seeds in August and October resulted in rhizome enlargement from the tenth and fifth internodes, respectively. Rhizomes enlarged in the November-sowing but elongated in the May-sowing irrespective of temperature treatments under natural daylength in the phytotron rooms. The seedlings cultivated from May at 25-30 degrees C for 2 months had more leaves, and more rhizome branches and nodes than those cultivated from November. CONCLUSIONS: Short days led to induced dormancy in lotus.  (+info)

(S)-armepavine inhibits human peripheral blood mononuclear cell activation by regulating Itk and PLCgamma activation in a PI-3K-dependent manner. (2/22)

Chinese herbs are useful edible and medicinal plants for their immune modulatory functions. We have proven that (S)-armepavine (C19H23O3N; MW313) from Nelumbo nucifera inhibits the proliferation of human PBMCs activated with PHA and improves autoimmune diseases in MRL/MpJ-lpr/lpr mice. In the present study, the pharmacological activities of (S)-armepavine were evaluated in PHA-activated PBMCs. The results showed that (S)-armepavine suppressed PHA-induced PBMC proliferation and genes expression of IL-2 and IFN-gamma without direct cytotoxicity. Inhibition of NF-AT and NF-kappaB activation suggested phospholipase Cgamma (PLCgamma)-mediated Ca2+ mobilization and protein kinase C activation were blocked by (S)-armepavine. Phosphorylation of PLCgamma is regulated by lymphocyte-specific kinase (Lck), ZAP-70, and IL-2-inducible T cell kinase (Itk). We found (S)-armepavine inhibited PHA-induced phosphorylation of Itk and PLCgamma efficiently but did not influence Lck or ZAP-70 phosphorylation. In addition, ZAP-70-mediated pathways, such as the association of linker for activation of T cells with PLCgamma and activation of ERK, were also intact in the presence of (S)-armepavine. Finally, reduction of phosphoinositide 3,4,5-trisphosphate formation and Akt phosphorylation suggested that (S)-armepavine inhibited Itk, and PLCgamma phosphorylation might be a result of the influence of PI-3K activation. Addition of exogenous IL-2 or PMA/A23187 rescued PBMC proliferation in the presence of (S)-armepavine. Therefore, we concluded that (S)-armepavine inhibited PHA-induced cell proliferation and cytokine production in a major way by blocking membrane-proximal effectors such as Itk and PLCgamma in a PI-3K-dependent manner.  (+info)

Effects of plant extract neferine on cyclic adenosine monophosphate and cyclic guanosine monophosphate levels in rabbit corpus cavernosum in vitro. (3/22)

AIM: To further investigate the relaxation mechanism of neferine (Nef), a bis-benzylisoquinoline alkaloid extracted (isolated) from the green seed embryo of Nelumbo nucifera Gaertn in China, on rabbit corpus cavernosum tissue in vitro. METHODS: The effects of Nef on the concentrations of cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP) in isolated and incubated rabbit corpus cavernosum tissue were recorded using 125I radioimmunoassay. RESULTS: The basal concentration of cAMP in corpus cavernosum tissue was 5.67 +/- 0.97 pmol/mg. Nef increased the cAMP concentration in a dose-dependent manner (P < 0.05), but this effect was not inhibited by an adenylate cyclase inhibitor (cis-N-[2-phenylcyclopentyl]azacyclotridec-1-en-2-amine, MDL-12, 330A) (P > 0.05). The accumulation of cAMP induced by prostaglandin E1 (PGE1, a stimulator of cAMP production) was also augmented by Nef in a dose-dependent manner (P < 0.05). The basal concentration of cGMP in corpus cavernosum tissue is 0.44 +/- 0.09 pmol/mg. Nef did not affect this concentration of cGMP, either in the presence or in the absence of a guanyl cyclase inhibitor (1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one, ODQ) (P > 0.05). Also, sodium nitroprusside (SNP, a stimulator of cGMP production)-induced cGMP production was not enhanced by Nef (P > 0.05). CONCLUSION: Nef, with its relaxation mechanism, can enhance the concentration of cAMP in rabbit corpus cavernosum tissue, probably by inhibiting phosphodiesterase activity.  (+info)

Synchronicity of thermogenic activity, alternative pathway respiratory flux, AOX protein content, and carbohydrates in receptacle tissues of sacred lotus during floral development. (4/22)

 (+info)

Kaempferol isolated from Nelumbo nucifera stamens negatively regulates FcepsilonRI expression in human basophilic KU812F cells. (5/22)

Mast cells and basophils perform important functions as pivotal effector cells in IgE-mediated allergic reactions. KU812F cells, a human basophilic cell line isolated originally from chronic myelocytic leukemia, express a high affinity receptor of IgE, FcepsilonRI. Kaempferol was extracted and isolated from a methanolic extract of flavonoid-rich Nelumbo nucifera stamens. In the present study, the inhibitory effects of kaempferol on FcepsilonRI expression in human basophilic KU812F cells was examined. Flow cytometric analysis revealed that FcepsilonRI expression on the cell surface was suppressed in a concentration-dependent manner when the cells were cultured with kaempferol. Moreover, RTPCR analysis showed that the mRNA levels for FcepsilonRI alpha- and gamma-chains were reduced as the result of kaempferol treatment in a concentration-dependent manner. Kaempferol showed its suppressive effects on intracellular Ca2+ concentration and histamine release from anti-FcepsilonRI alpha- chain antibody-stimulated cells in a concentration-dependent manner. These observations indicate that kaempferol may exert antiallergic effect via downregulation of FcepsilonRI expression and degranulation.  (+info)

Two cys or not two cys? That is the question; alternative oxidase in the thermogenic plant sacred Lotus. (6/22)

 (+info)

Effective pollinators of Asian sacred lotus (Nelumbo nucifera): contemporary pollinators may not reflect the historical pollination syndrome. (7/22)

 (+info)

Inhibitory effects of armepavine against hepatic fibrosis in rats. (8/22)

 (+info)

• 1
• 2
• 3