Volume 1 Issue 1
Authors: Nader Noroozi Pesyan; Mohammad Jalilzadeh
Abstract: One-pot reaction of unsymmetrical 1-methybarbituric acid (1-MBA), BrCN, mono- and dialdehydes in the presence of L-(+)-tartaric acid (L-(+)-TA) and/or triethylamine afforded diastereomeric mixtures of a series of stable heterocyclic mono- and bis-spiro barbiturates and their sulfur analogues which are dimeric forms of barbiturate (uracil and thiouracil derivative) at the range of 0°C to room temperature. The reaction of symmetrical (thio)barbituric acids with dialdehydes were afforded bis-spiro barbiturates instead, 1-MBA was afforded diastereomeric mixture of bis-spiro barbiturates under the same condition. Diastereoselectively reaction products in the presence of L-(+)-TA were also investigated. Structure elucidation is carried out by 1H NMR, 13C NMR, FT-IR and Mass analyses. Mechanism of the formation is discussed.
Keywords: Diastereoselective; Unsymmetrical Barbituric Acid; Spiro[furo[2;3-d] Pyrimidine; BrCN; Uracil; Thiouracil; L-(+)-tartaric Acid
Authors: Tamás Kömíves; Erik Molnár; Katalin Pilinszky; György György Heltai; Gábor Gullner; András Bittsánszky; Gábor Gyulai
Abstract: For gene reactivation DNA demethylating agent DHAC (5,6-dihydro-5'-azacytidine hydrochloride) (10-4 M for 7 days) was applied in aseptic leaf cultures of wild type (WT) and 35S-gshI-rbcS GM (genetically modified) transgenic (TR) poplar (Populus x canescens) clone lgl6. Gene expression levels were determined by RT-qPCR (reverse transcriptase quantitative PCR) measuring the mRNA levels of the prokaryotic gshI-rbcS-mRNA (γ-glutamylcysteine synthetase) cloned from E. coli, and two endogenous poplar genes of gsh1-mRNA and gst-mRNA (glutathione S-transferase). For internal control, the constitutively expressed housekeeping poplar genes α-tubulin and actin were used, and the 2−ΔΔCt method was applied for data analysis. After DHAC treatment the expression levels of 35S-gshI-rbcS transgene showed a double (1.8 - times) increment. The endogenous poplar gene gsh1 increased by 19.7-fold in the WT, and by 8.7-fold in the TR clone. The endogenous gst gene showed a 4.9 - times (in WT) and a 2.9-times (in TR) increment. Sequences of DNA methylating enzymes were analyzed in silico and significant distinction was found among the three main plant DNA methylases (METases) of METs (maintenance methyltranferase), CMTs (chromomethylases) and DRMs (de novo domains rearranged DNA methylases). The DHAC-treated WT poplars with increased gene expressions of gsh1 and gst might provide novel plant sources for application for detoxification and soil remediation concerning general public frightened by GM poplars.
Keywords: Populus x canescens； DNA Demethylation； RT-qPCR
Authors: Manuel Carmona; María María Teresa García; Ángela Ángela Alcázar; Juan F. Rodriguez; Ángel Ángel Carnicer
Abstract: Two different ways to purify crude glycerol have been proposed depending on the catalyst used in the biodiesel production. When alkalis as NaOH or KOH are used ion exchange and adsorption could be advantageously employed to remove the salt and water content respectively. In this work, the water removal is accomplished by using three different molecular sieves zeolite 5A in Na+ and Ca2+-form, Zeolita A in Na+ and Ca2+-form and Zeolita A in K+-form commonly applied for water adsorption. The larger water sorption capacity of the zeolite 5A-Na, Ca at 303 K allowed selecting it as the best choice for the dehydration of glycerol. The adsorption experimental data were fitted with the adsorption model of Tóth and further experiments have been carried out at 318 and 333 K with the aim to obtain the thermodynamic properties △Hº and △Sº. The negative values of these both properties indicated that this adsorption process is exothermic and feasible. On the other hand, when sodium or potassium alkoxides are used in the biodiesel production water is not involved in glycerol purification. Thus, ion exchange studies for the systems H+/Na+ and H+/K+ using the resin Amberlite 252 for a solution containing a mixture 50/50 of glycerine in methanol and a methoxide content of 0.25 mol L-1 at 298 K were carried out. Langmuir equation was used to fit the experimental equilibrium data and the shape of the isotherm confirms the irreversibility of the process leading to the methanol production. It was obtained that the Langmuir separation factor is independent on the system but the maximum ion uptake is higher for the K+ than Na+ attending to its low hydrated radii. These results confirm the feasibility to purify glycerol streams by applying the proper technology in a aqueous or non-aqueous media.
Keywords: Glycerol; Ion Exchange; Adsorption; Biodiesel