Hydrazides in the Processes of Extraction of Non-ferrous Metals from Ammonia Solutions

The extraction of copper and other non-ferrous metals from ammonia solutions with hydrazides оf Versatic acids (C15–C19 fraction) is discussed in this article. Hydrazide group has been known to be a selective extractant for non-ferrous metals. Introducing the alkyl radical of -branched tert-carboxylic acids into the reagent structure may lead to new properties important for an extractant, such as chemical stability and good compatibility with solvents properties. The optimal extraction conditions, the effect of ammonium salts and the regularities of re-extraction are assessed. Keywords: extraction, hydrazides,  -branched tert-carboxylic acids, non-ferrous metal

ИОННАЯ ФЛОТАЦИЯ ЦВЕТНЫХ МЕТАЛЛОВ С СУЛЬФОНИЛЬНЫМИ ПРОИЗВОДНЫМИ АМИНОТИОФЕНОВ

The paper studies sulfonyl aminothiophene derivatives as potential collecting agents in ion flotation of non-ferrous metals. The study determines optimal flotation conditions of Cu(II), Co(II), Ni(II), Zn(II) and Cd(II): range of pH values, process time, and amount of reagent. It demonstrates effectiveness of compounds as collecting agents for non-ferrous metals in standardized test solutions by the method of ion flotation.В качестве потенциальных собирателей для ионной флотации цветных металлов исследованы сульфонильные производные аминотиофенов. Найдены оптимальные условия флотации Cu(II), Co(II), Ni(II), Zn(II) и Cd(II): область значений рН, длительность процесса, количество реагента. Показана эффективность соединений как собирателей цветных металлов из модельных растворов методом ионной флотации

Evidence for Antisense Transcription Associated with MicroRNA Target mRNAs in Arabidopsis

Antisense transcription is a pervasive phenomenon, but its source and functional significance is largely unknown. We took an expression-based approach to explore microRNA (miRNA)-related antisense transcription by computational analyses of published whole-genome tiling microarray transcriptome and deep sequencing small RNA (smRNA) data. Statistical support for greater abundance of antisense transcription signatures and smRNAs was observed for miRNA targets than for paralogous genes with no miRNA cleavage site. Antisense smRNAs were also found associated with MIRNA genes. This suggests that miRNA-associated “transitivity” (production of small interfering RNAs through antisense transcription) is more common than previously reported. High-resolution (3 nt) custom tiling microarray transcriptome analysis was performed with probes 400 bp 5′ upstream and 3′ downstream of the miRNA cleavage sites (direction relative to the mRNA) for 22 select miRNA target genes. We hybridized RNAs labeled from the smRNA pathway mutants, including hen1-1, dcl1-7, hyl1-2, rdr6-15, and sgs3-14. Results showed that antisense transcripts associated with miRNA targets were mainly elevated in hen1-1 and sgs3-14 to a lesser extent, and somewhat reduced in dcl11-7, hyl11-2, or rdr6-15 mutants. This was corroborated by semi-quantitative reverse transcription PCR; however, a direct correlation of antisense transcript abundance in MIR164 gene knockouts was not observed. Our overall analysis reveals a more widespread role for miRNA-associated transitivity with implications for functions of antisense transcription in gene regulation. HEN1 and SGS3 may be links for miRNA target entry into different RNA processing pathways

Nucleo-cytoplasmic transport of proteins and RNA in plants

Merkle T. Nucleo-cytoplasmic transport of proteins and RNA in plants. Plant Cell Reports. 2011;30(2):153-176.Transport of macromolecules between the nucleus and the cytoplasm is an essential necessity in eukaryotic cells, since the nuclear envelope separates transcription from translation. In the past few years, an increasing number of components of the plant nuclear transport machinery have been characterised. This progress, although far from being completed, confirmed that the general characteristics of nuclear transport are conserved between plants and other organisms. However, plant-specific components were also identified. Interestingly, several mutants in genes encoding components of the plant nuclear transport machinery were investigated, revealing differential sensitivity of plant-specific pathways to impaired nuclear transport. These findings attracted attention towards plant-specific cargoes that are transported over the nuclear envelope, unravelling connections between nuclear transport and components of signalling and developmental pathways. The current state of research in plants is summarised in comparison to yeast and vertebrate systems, and special emphasis is given to plant nuclear transport mutants