The purpose of this study was to determine and characterize the biodegradation of reactive dyes on cotton jersey fabrics buried in soil. Four commonly-used reactive dyes, C. I. Reactive Black 5 (RBlk5), C. I. Reactive Red 198 (RR198), C. I. Reactive Blue 49 (RB49), and C. I. Reactive
Orange 35 (RO35), were used in this study. Degradation products were characterized and proposed based on high-performance liquid chromatography (HPLC) coupled with high-resolution mass spectrometry (HRMS). A chemical method and an enzymatic digestion were developed and used to remove the reactive
dye from the control and degraded cotton fabrics. Hydrolyzed reactive dyes and reactive dyes having cellobiose units were synthesized and used as standards for comparison in this study. The possible degradation mechanism pathways of the reactive dyes bonded to cotton fabrics depends on the
chemical structure of each dye.
Embryonic stem (ES) cells are characterized by the expression of an extensive and interconnected network of pluripotency factors which are downregulated in specialized cells. Epigenetic mechanisms, including DNA methylation and histone modifications, are also important in maintaining this pluripotency program in ES cells and in guiding correct differentiation of the developing embryo. Methylation of the cytosine base of DNA blocks gene expression in all cell types and further modifications of methylated cytosine have recently been discovered. These new modifications, putative intermediates in a pathway to erase DNA methylation marks, are catalyzed by the ten-eleven translocation (Tet) proteins, specifically by Tet1 and Tet2 in ES cells. Surprisingly, Tet1 shows repressive along with active effects on gene expression depending on its distribution throughout the genome and co-localization with Polycomb Repressive Complex 2 (PRC2). PRC2 di- and tri-methylates lysine 27 of histone 3 (H3K27me2/3 activity), marking genes for repression. In ES cells, almost all gene loci containing the repressive H3K27me3 modification also bear the active H3K4me3 modification, creating “bivalent domains” which mark important developmental regulators for timely activation. Incorporation of Tet1 into the bivalent domain paradigm is a new and exciting development in the epigenetics field, and the ramifications of this novel crosstalk between DNA and histone modifications need to be further investigated. This knowledge would aid reprogramming of specialized cells back into pluripotent stem cells and advance understanding of epigenetic perturbations in cancer.
In this study, reactive dye degradation products after landfilling were extracted by a modified QuEChERS extraction method and detected by high-resolution QTOF mass spectrometry.
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