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Protoporphyrinogen Oxidase (protoporphyrinogen + oxidase)
Selected AbstractsSyntheses and herbicidal activity of pyrazolyl benzoxazole derivativesJOURNAL OF HETEROCYCLIC CHEMISTRY, Issue 1 2010Na Xue In recent years, protoporphyrinogen oxidase (Protox) inhibitor herbicides are developed rapidly, because of this type of herbicides shows high herbicidal activity and low toxicity. In this paper, we prepared a series of new substituted pyrazolyl benzoxazole derivative, which were synthesized from 4-fluorophenol, via a serial of reactions included chlorination, acylation, condensation, ring closure, methylation, nitration, and so on. All the structures are confirmed by 1H NMR, MS and element analysis. Preliminary bioassay shows that most substituted pyrazolyl benzoxazole derivatives exhibit high herbicidal activity to the tested gramineous weeds and latifoliate weeds. J. Heterocyclic Chem., (2010). [source] Recovery from a variegate porphyria by a liver transplantationLIVER TRANSPLANTATION, Issue 7 2004Nathalie Stojeba The porphyrias are a group of inherited or acquired enzymatic defects of heme biosynthesis. Each type of porphyria has a characteristic pattern of overproduction and accumulation of heme precursors based on the location of dysfunctional enzyme in the heme synthetic pathway. Variegate porphyria, one of the acute hepatic porphyrias, is characterized by a partial reduction in protoporphyrinogen oxidase, the seventh enzyme of the heme biosynthetic pathway. A case of liver transplantation is described with a recovery from a variegate porphyria. Acute porphyria is commonly worsened by a wide variety of medications. We describe a step-by-step perioperative management protocol. (Liver Transpl 2004;10:935,938.) [source] Candida albicans lacking the frataxin homologue: a relevant yeast model for studying the role of frataxinMOLECULAR MICROBIOLOGY, Issue 2 2004Renata Santos Summary We cloned the CaYFH1 gene that encodes the yeast frataxin homologue in Candida albicans. CaYFH1 was expressed in ,yfh1 Saccharomyces cerevisiae cells, where it compensated for all the phenotypes tested except for the lack of cytochromes. Double ,Cayfh1/,Cayfh1 mutant had severe defective growth, accumulated iron in their mitochondria, lacked aconitase and succinate dehydrogenase activity and had defective respiration. The reductive, siderophore and haem uptake systems were constitutively induced and the cells excreted flavins, thus behaving like iron-deprived wild-type cells. Mutant cells accumulated reactive oxygen species and were hypersensitive to oxidative stress, but not to iron. Cytochromes were less abundant in mutants than in wild-type cells, but this did not result from defective haem synthesis. The low cytochrome concentration in mutant cells was comparable to that of iron-deprived wild-type cells. Mitochondrial iron was still available for haem synthesis in ,Cayfh1/,Cayfh1 cells, in contrast to S. cerevisae,yfh1 cells. CaYFH1 transcription was strongly induced by iron, which is consistent with a role of CaYfh1 in iron storage. Iron also regulated transcription of CaHEM14 (encoding protoporphyrinogen oxidase) but not that of CaHEM15 (encoding ferrochelatase). There are thus profound differences between S. cerevisiae and C. albicans in terms of haem synthesis, cytochrome turnover and the role of frataxin in these processes. [source] Dual targeting of Myxococcus xanthus protoporphyrinogen oxidase into chloroplasts and mitochondria and high level oxyfluorfen resistancePLANT CELL & ENVIRONMENT, Issue 11 2004S. JUNG ABSTRACT Much attention has been paid to the signal sequences of eukaryotic protoporphyrinogen oxidases (protoxes); both the organelles targeted by protoxes and the role of protoxes in conferring resistance against protox-inhibiting herbicides, such as oxyfluorfen, have been examined. However, there have been no reports on the translocation of prokaryotic protoxes. This study investigated the targeting ability of Myxococcus xanthus protox in vitro and in vivo. In an in vitro translocation assay using a dual import system, M. xanthus protein was detected in chloroplasts and mitochondria, suggesting that the M. xanthus protox protein was targeted into both organelles. In order to confirm the in vitro dual targeting ability of M. xanthus, we used a stable transgenic strategy to investigate dual targeting in vivo. In transgenic rice plants overexpressing M. xanthus protox, M. xanthus protox antibody cross-reacted with proteins with predicted molecular masses of 50 kDa from both chloroplasts and mitochondria, and this in vivo transgene expression corresponded to a prominent increase in chloroplastic and mitochondrial protox activity. Seeds from the transgenic lines M4 and M7 germinated in solid Murashige and Skoog media of up to 500 µm of oxyfluorfen, whereas wild-type seeds did not germinate in 1 µm. After 4-week-old-rice plants were treated with oxyfluorfen for 3 d, lines M4 and M7 exhibited normal growth, whereas the wild-type line was severely bleached and necrotized. The herbicidal resistance is attributed to the insignificant accumulation of photodynamic protoporphyrin IX in cytosol because the high chloroplastic and mitochondrial protox activity in oxyfluorfen-treated transgenic lines, compared with that in oxyfluorfen-treated and untreated wild-type plants, metabolizes protoporphyrinogen IX to chlorophyll and heme. A practical application of the dual targeting of M. xanthus protox for obtaining outstanding resistance to peroxidizing herbicides is discussed. [source] | ||||||||||