ABSTRACT
Lipoxygenases (linoleate: oxygen oxidoreductase, EC 1.13.11.12; LOXs) are encoded by a multi-gene family in plants. The LOXs are monomeric non-heme, non-sulfur iron dioxygenases, which catalyze the incorporation of molecular oxygen into polyunsaturated fatty acids containing a cis, cis-1,4-pentadiene moiety. The LOX isoforms are distinguished by differences in optimum pH of the reaction, pI, substrate and product specificity, spatial and temporal expression, and subcellular localization. The function of various LOXs in plants has been suggested. Some of the physiological processes in which lipoxygenases have been implicated include wounding, pathogen attack, seed germination, fruit ripening, plant senescence, and synthesis of Abscisic acid (ABA) and Jasmonic acid (JA). During normal vegetative and reproductive growth, lipoxygenases have also been suggested to act as vegetative storage proteins, participate in transference of lipoid, and response to nutrient stress and source/sink relationships. Significant progress in understanding LOX families will be beneficial to the application of the LOX in crop breeding, research on new-type phytoalexin and food industry.
Subject(s)
Gene Expression Regulation, Plant , Lipoxygenase , Genetics , Metabolism , Multigene Family , Plants , Protein Isoforms , Genetics , MetabolismABSTRACT
A novel gene, which was a homologue of Arabidopsis COI1 was isolated from rice (Oryza sativa L.) by RT-PCR and designated as OsCOI1. It encoded a protein of 595 amino acids. The similar F-box motif and 16 leucine-rich repeats were found in the deduced protein OsCOI1. OsCOI1 and COI1 showed high homology (74%) at amino acid level. Semi-quantitative RT-PCR and Northern blot analysis demonstrated that the expression of OsCOI1 in rice varied obviously after treatment with MeJA and ABA but was not affected by SA and ET, suggesting that the specific function of OsCOI1 in JA signal pathway and related ABA pathway.
ABSTRACT
OBJECTIVE:To study the production process of ceftizoxime sodium.METHODS:Ceftizoxime acid was prepared with 7-Amino-3-norcephem-4-carboxylic acid(7-ANCA)and AE-ester ceftizoxime acid as raw material;then ceftizoxime sodium was obtained through the reaction between ceftizoxime acid and sodium carbonate.The effects of parameters including reaction time,and amount and dripping velocity of ethanol,the amount of sodium carbonate,and pH of solution on quality of product were studied.RESULTS:The reaction process could be realized successfully.The optimal parameters for the synthesis of ceftizoxime sodium were as follows:reaction time=1.5h,the velocity of dripping ethanol=400mL? h-1,reaction temperature