Search

Pressures to ban bisphenol A (BPA) has led to the use of alternate chemicals such as BPA analogues bisphenol S (BPS) and bisphenol AF (BPAF) in production of consumer products; however, information on their environmental fate is scarce. In this study, aerobic degradation of BPA, BPAF, and BPS at 100 μg/kg soil and 22 ± 2 °C was monitored for up to 180 days in a forest soil and an organic farm soil. At each sampling point, soils were extracted three times and analyzed by liquid chromatography high resolution mass or time-of-flight mass spectrometry. Based on compound mass recovered from soils compared to the mass applied, BPS had short half-lives of <1 day in both soils similar to BPA. BPAF was much more persistent with observed half-lives of 32.6 and 24.5 days in forest and farm soils, respectively. To our knowledge, this is the first report on BPAF degradation. For all three compounds, half-lives were longer in the higher organic carbon (OC) forest soil which correlates well to sorption studies showing higher sorption with higher OC. Metabolites identified for all three bisphenols support degradation pathways that include meta-cleavage as well as ortho-cleavage, which has not been previously shown. [ABSTRACT FROM AUTHOR]

Members of the mammalian tristetraprolin family of CCCH tandem zinc finger proteins can bind to certain AU-rich elements (AREs) in mRNAs, leading to their deadenylation and destabilization. Mammals express three or four members of this family, but Drosophila melanogaster and other insects appear to contain a single gene, Tis11. We found that recombinant Drosophila Tis11 protein could bind to ARE-containing RNA oligonucleotides with low nanomolar affinity. Remarkably, co-expression in mammalian cells with "target" RNAs demonstrated that Tis11 could promote destabilization of ARE-containing mRNAs and that this was partially dependent on a conserved C-terminal sequence resembling the mammalian NOT1 binding domain. Drosophila Tis11 promoted both deadenylation and decay of a target transcript in this heterologous cell system. We used chromosome deletion/duplication and P element insertion to produce two types of Tis11 deficiency in adult flies, both of which were viable and fertile. To address the hypothesis that Tis11 deficiency would lead to the abnormal accumulation of potential target transcripts, we analyzed gene expression in adult flies by deep mRNA sequencing. We identified 69 transcripts from 56 genes that were significantly up-regulated more than 1.5-fold in both types of Tis11-deficient flies. Ten of the up-regulated transcripts encoded probable proteases, but many other functional classes of proteins were represented. Many of the up-regulated transcripts contained potential binding sites for tristetraprolin family member proteins that were conserved in other Drosophila species. Tis11 is thus an ARE-binding, mRNA-destabilizing protein that may play a role in post-transcriptional gene expression in Drosophila and other insects. [ABSTRACT FROM AUTHOR]

Motivation: The power of a microarray experiment derives from the identification of genes differentially regulated across biological conditions. To date, differential regulation is most often taken to mean differential expression, and a number of useful methods for identifying differentially expressed (DE) genes or gene sets are available. However, such methods are not able to identify many relevant classes of differentially regulated genes. One important example concerns differentially co-expressed (DC) genes. [ABSTRACT FROM PUBLISHER]

The molecular basis of programmed cell death (PCD) of neurons during early metamorphic development of the central nervous system (CNS) in Drosophila melanogaster are largely unknown, in part owing to the lack of appropriate model systems. Here, we provide evidence showing that a group of neurons (vCrz) that express neuropeptide Corazonin (Crz) gene in the ventral nerve cord of the larval CNS undergo programmed death within 6 hours of the onset of metamorphosis. The death was prevented by targeted expression of caspase inhibitor p35, suggesting that these larval neurons are eliminated via a caspase-dependent pathway. Genetic and transgenic disruptions of ecdysone signal transduction involving ecdysone receptor-B (EcR-B) isoforms suppressed vCrz death, whereas transgenic re-introduction of either EcR-B1 or EcR-B2 isoform into the EcR-B-null mutant resumed normal death. Expression of reaper in vCrz neurons and suppression of vCrz-cell death in a reaper-null mutant suggest that reaper functions are required for the death, while no apparent role was found for hid or grim as a death promoter. Our data further suggest that diap1 does not play a role as a central regulator of the PCD of vCrz neurons. Significant delay of vCrz-cell death was observed in mutants that lack dronc or dark functions, indicating that formation of an apoptosome is necessary, but not sufficient, for timely execution of the death. These results suggest that activated ecdysone signaling determines precise developmental timing of the neuronal degeneration during early metamorphosis, and that subsequent reaper-mediated caspase activation occurs through a novel DIAP1-independent pathway. [ABSTRACT FROM AUTHOR]

Hemolytic uremic syndrome (HUS) is a rare thrombotic complication characterized by a triad of microangiopathic hemolytic anemia, thrombocytopenia, and acute renal failure. HUS may be caused by several different conditions, including infection, malignancy, and chemotherapeutic agents, such as mitomycin, cisplatin, and most recently, gemcitabine. The outcome of gemcitabine-induced HUS is poor, and the disease has a high mortality rate. This study reports a case of gemcitabine-induced HUS in a patient with pancreatic cancer in Korea. [ABSTRACT FROM AUTHOR]

Although the corazonin gene ( Crz) has been molecularly characterized, little is known concerning the function of this neuropeptide in Drosophila melanogaster. To gain insight into Crz function in Drosophila, we have investigated the developmental regulation of Crz expression and the morphology of corazonergic neurons. From late embryo to larva, Crz expression is consistently detected in three neuronal groups: dorso-lateral Crz neurons (DL), dorso-medial Crz neurons (DM), and Crz neurons in the ventral nerve cord (vCrz). Both the vCrz and DM groups die via programmed cell death during metamorphosis, whereas the DL neurons persist to adulthood. In adults, Crz is expressed in a cluster of six to eight neurons per lobe in the pars lateralis (DLP), in numerous neuronal cells in the optic lobes, and in a novel group of four abdominal ganglionic neurons present only in males (ms-aCrz). The DLP group consists of two subsets of cells having different developmental origins: embryo and pupa. In the optic lobes, we have detected both Crz transcripts and Crz promoter activity, but no Crz-immunoreactive products, suggesting a post-transcriptional regulation of Crz mRNA. Projections of the ms-aCrz neurons terminate within the ventral nerve cord, implying a role as interneurons. Terminals of the DLP neurons are found in the retrocerebral complex that produces juvenile hormone and adipokinetic hormone. Significant reduction of trehalose levels in adults lacking DLP neurons suggests that DLP neurons are involved in the regulation of trehalose metabolism. Thus, the tissue-, stage-, and sex-specific expression of Crz and the association of Crz with the function of the retrocerebral complex suggest diverse roles for this neuropeptide in Drosophila. [ABSTRACT FROM AUTHOR]