Project description:Comparative transcriptome analysis of Methylibium petroleiphilum PM1 exposed to the fuel-oxygenates methyl-tert-butyl ether and ethanol High-density whole genome cDNA microarrays were used to investigate substrate-dependent gene expression of Methylibium petroleiphilum PM1, one of the best-characterized aerobic methyl tert-butyl ether (MTBE)-degrading bacteria. Differential gene expression profiling was conducted with PM1 grown on MTBE and ethanol as sole carbon sources. Based on microarray high scores and protein similarity analysis, an MTBE regulon located on the megaplasmid was identified for further investigation. Putative functions for enzymes encoded in this regulon are described with relevance to the predicted MTBE degradation pathway. A new unique dioxygenase enzyme system that carries out the hydroxylation of TBA to 2-methyl-2-hydroxy-1-propanol in M. petroleiphilum PM1 was discovered. Based on the expression data, hypotheses regarding the acquisition and evolution of MTBE genes as well as the involvement of IS elements in these complex processes were formulated. The pathways for toluene, phenol, and alkane oxidation via toluene monooxygenase, phenol hydroxylase, alkane monooxygenase as well as propane monooxygenase, respectively, were upregulated in MTBE-grown cells compared to ethanol-grown cells. Four out of nine putative cyclohexanone monooxygenases were also upregulated in MTBE-grown cells. The global transcriptome response revealed the link between metabolism of MTBE and aromatic compounds (e.g. benzene, toluene) present in gasoline mixtures. The expression data aids our understanding of the regulation of metabolic processes that may occur in response to pollutant mixtures and perturbations in the environment. Keywords: bacterial metabolism
Project description:Methyl tert-butyl ether (MTBE) has been shown to target developing vasculature in piscine and mammalian model systems. In the zebrafish, MTBE induces vascular lesions throughout development. These lesions result from exposure to MTBE at an early stage in development (6-somites to Prim-5 stages). During this time period, transcript levels of vegfa, vegfc, and vegfr1 were significantly decreased in embryos exposed to 5 mM MTBE. We performed global gene analysis as an unbiased approach to discover possible modes of action of MTBE vascular toxicity.
Project description:Vitiligo, an acquired disorder characterized by depigmented skin patches, results from loss of epidermal melanocytes. Etiology of vitiligo is not clearly understood but environmental, biochemical, genetic, and immune factors play a role in its pathogenesis. There is evidence that melanocyte death is perpetuated by an autoimmune response that causes lesions to spread. 4-tertiary butyl phenol (4TBP) and monobenzyl ether of hydroquinone (MBEH) are phenolic compounds that are known as environmental causes of vitiligo. We used microarray to detail the global gene expression that occurs following exposure of melanocytes to 4-TBP or MBEH to identified distinct classes of up-regulated genes that may contribute to melanocyte loss in vitiligo. We show that human melanocytes exposed to 4-TBP and MBEH show increased production of some inflammatory cytokines. Interleukin-6 (IL6) and IL8, in particular, are expressed at the periphery of vitiligo lesions and may contribute to recruitment of immune components to the areas, perpetuating melanocyte loss. Cultured human epidermal melanocytes were treated with 4TBP or MBEH for 3, 6, or 24 hours and gene expression were compared with untreated cells.
Project description:In our continuing study of the desmosdumotin C (1) series, twelve new analogues, 21–32, mainly with A-ring modifications, were prepared and evaluated for in vitro anticancer activity against several human tumor cell lines. Among them, the 4′-iodo-3,3,5-tripropyl-4-methoxy analogue (31) showed significant cytotoxicity against multiple human tumor cell lines with ED50 values of 1.1–2.8 microM. Elongation of the C-3 and C-5 carbon chains reduced activity relative to propyl substituted analogues; however, activity was still better than that of natural 1. Among analogues with various ether groups on C-4, compounds with methyl (2) and propyl (26) ethers inhibited cell growth of multiple tumor cells lines, while 28 with an iso-butyl ether showed selective cytotoxicity against lung cancer A549 cells (ED50 1.7 microM). The gene expression profiles showed that 3 may modulate the spindle assembly checkpoint (SAC) and chromosome separation, and thus, arrest cells at the G2/M-phase. We used microarrays to elucidate the underlying antitumor mechanism induced by Desmosdumotin C Analog
Project description:Vitiligo, an acquired disorder characterized by depigmented skin patches, results from loss of epidermal melanocytes. Etiology of vitiligo is not clearly understood but environmental, biochemical, genetic, and immune factors play a role in its pathogenesis. There is evidence that melanocyte death is perpetuated by an autoimmune response that causes lesions to spread. 4-tertiary butyl phenol (4TBP) and monobenzyl ether of hydroquinone (MBEH) are phenolic compounds that are known as environmental causes of vitiligo. We used microarray to detail the global gene expression that occurs following exposure of melanocytes to 4-TBP or MBEH to identified distinct classes of up-regulated genes that may contribute to melanocyte loss in vitiligo. We show that human melanocytes exposed to 4-TBP and MBEH show increased production of some inflammatory cytokines. Interleukin-6 (IL6) and IL8, in particular, are expressed at the periphery of vitiligo lesions and may contribute to recruitment of immune components to the areas, perpetuating melanocyte loss.