No abstract

Two series of modified oligonucleotides based on the self-complementary dodecamer d(CGCTAATTAGCG) were synthesized. The first contained the -C identical withCCH2R linker at C5 of deoxyuridine at position 4 (T*) of d(CGCT*AATTAGCG) and the second contained the -SR linker. The goal of the study was to evaluate and compare these two types of side chains for suitability as tethers for linking reporter groups to oligonucleotides. Our primary concern was how these tethers would effect duplex stability. The modified nucleosides were synthesized by palladium-mediated coupling reactions between the substituted alkyne and 5'-(4, 4'-dimethoxytrityl)-5-iodo-2'-deoxyuridine and between a disulfide and 5-chloromercurio-2'-deoxyuridine. The C5 deoxyuridine side chains evaluated included C identical with CCH3, C identical with CCH2NHC(O)CH3, C identical with CCH2N(CH3)2, C identical with CCH2N-HC(O)C5H4N, C identical with CCH2NHC(O)C10H15, SCH3, SC6H5 and SCH2CH2NHC(O)CH3. The nucleosides containing these substituents were incorporated into oligo-deoxyribonucleotides by standard phosphoramidite methodology. Melting studies demonstrated that the sequence containing the C identical with CCH3side chain had the highest T m value (59.1 degrees C) in comparison with the control sequence (T m = 55.2 degrees C) and that any additional substituent on C3 of the propynyl group lowered the T m value relative to propynyl. Nevertheless, even the most destabilizing substituent, adamantylcarbamoyl, yielded an oligodeoxyribonucleotide that dissociated with a T m of 54 degrees C, which is only 1.2 degrees C less than the control sequence. In contrast, the thioether substituents led to lower T m values, ranging from as low as 45.1 degrees C for SPh up to 52.2 degrees C for SMe. Replacing the methyl of the SMe substituent with a CH2CH2NHC(O)CH3 tether led to no further reduction in melting temperature. The T m value of the CH2CH2NHC(O)CH3-containing oligonucleotide was less than the natural sequence by 1.6 degrees C/substituent. This is sufficiently small that it is anticipated that the C5 thioether linkage may be as useful as the acetylenic linkage for tethering reporter groups to oligonucleotides. More importantly, the thioether linkage provides a means to position functional groups to interact specifically with opposing complementary (target) sequences.

A series of 7-N-acyllavendamycins with zero, one or two substituents at the C-2', C-3', and C-11' were synthesized through short and efficient methods. Pictet-Spengler condensation of 7-N-acylamino-2-formylquinoline-5,8-diones with tryptamine or tryptophans produced the desired lavendamycins. Screening data on a panel of three ras oncogene-transformed cell lines and the non-transformed parent cell line showed that a significant number of these analogues are potent antitumor agents and appear to be particularly active against K-ras transformed cells. Compared with the corresponding quinolinediones, these novel lavendamycins are much more inhibitory toward the transformed cells indicating that the beta-carboline moiety of the lavendamycin analogues plays an important role in its potency and selective toxicity.

No abstract

Due to complex composition of leachate, the comprehensive leachate treatment methods have been not demonstrated. Moreover, the improper management of leachate can lead to many environmental problems. The aim of this study was application of Fenton process for decreasing the major pollutants of landfill leachate on Kermanshah city. The leachate was collected from Kermanshah landfill site and treated by Fenton process. The effect of various parameters including solution pH, Fe2+ and H2O2 dosage, Fe2+/H2O2 molar ratio, and reaction time was investigated. The result showed that with increasing Fe2+ and H2O2 dosage, Fe2+/H2O2 molar ratio, and reaction time, the COD, TOC, TSS, and color removal increased. The maximum COD, TOC, TSS, and color removal were obtained at low pH (pH: 3). The kinetic data were analyzed in term of zero-order, first-order, and second-order expressions. First-order kinetic model described the removal of COD, TOC, TSS, and color from leachate better than two other kinetic models. In spite of extremely difficulty of leachate treatment, the previous results seem rather encouraging on the application of Fenton's oxidation.

No abstract

Rose is known as the first and the most important cutflowers in all over the world. One of the common methods of mass production of this plant is propagation through tissue culture. The main limiting factor of rose tissue culture is Bacterial contaminations and phenolic exudation in the establishment phase that significantly makes most of explants spoiled. Nano-Silver is able to control and stop the bacterial contamination. In this experiment Nano-Silver was added to medium with concentrations of (, , and ppm) and in the other experiments explants were immersed in solutions of Nano-Silver with concentrations (, , and ppm) in complete random design. The experiments were carried out with four replications. The results showed that the concentration of ppm which is directly added to the medium can reduce Bacterial contamination and phenolic exudation rate. Concentration of ppm for minutes after surface sterilization was the best treatment of immersion to control bacterial contaminations. High concentrations of Nano-Silver make regeneration of explants more and more slower and in some cases lead to destroy explants. In general, Nano-Silver had no effects on fungal contamination.

No abstract