ABSTRACT
The formation of phytoene by condensing two geranylgeranyl diphosphate molecules catalyzed by phytoene synthase (PSY) is the first committed and rate-limiting step in carotenoid biosynthesis, which has been extensively investigated in bacteria, land plants and microalgae. However, this step in macroalgae remains unknown. In the present study, a gene encoding putative phytoene synthase was cloned from the economic red alga Pyropia yezoensis-a species that has long been used in food and pharmaceuticals. The conservative motifs/domains and the tertiary structure predicted using bioinformatic tools suggested that the cloned PyPSY should encode a phytoene synthase; this was empirically confirmed by pigment complementation in E. coli. This phytoene synthase was encoded by a single copy gene, whose expression was presumably regulated by many factors. The phylogenetic relationship of PSYs from different organisms suggested that red algae are probably the progeny of primary endosymbiosis and plastid donors of secondary endosymbiosis.
Subject(s)
Geranylgeranyl-Diphosphate Geranylgeranyltransferase , Phylogeny , Rhodophyta , Rhodophyta/genetics , Rhodophyta/enzymology , Geranylgeranyl-Diphosphate Geranylgeranyltransferase/genetics , Geranylgeranyl-Diphosphate Geranylgeranyltransferase/metabolism , Carotenoids/metabolism , Escherichia coli/genetics , Cloning, Molecular , Edible Seaweeds , PorphyraABSTRACT
Baicalein is a widely used Chinese herbal medicine that has been used historically in anti-inflammatory and anti-cancer therapy. However, the molecular mechanism of its anti-cancer activity remains poorly understood and warrants further investigations. The purpose of this study is to verify the activity of baicalein to inhibit the invasion of MDA-MB-231 human breast cancer cells. The results indicated that baicalein suppressed MDA-MB-231 cell adhesion to fibronectin-coated substrate, wound healing migration and invasion through the Matrigel in a concentration-dependent manner. Western blot and gelatin zymography analysis showed that baicalein significantly inhibited the expression and secretion of matrix metalloproteinases 2/9 (MMP-2/9) in MDA-MB-231 cells. Additionally, treatment of MDA-MB-231 cells with baicalein down-regulated the expression of MMP-2/9 involved mitogen-activated protein kinases (MAPK) signaling pathway. Taken together, baicalein had potential to suppress the adhesion, migration and invasion of MDA-MB-231 cancer cells in vitro and it could serve as a promising drug for the treatment of cancer metastasis.
