SynopsisA Vilsmeier adduct derived from arylsulfonyl chlorides and DMF in pyridine was successfully used as a new condensating agent for the synthesis of aromatic polyesters by the direct polycondensation of aromatic dicarboxylic acjds and bisphenols and also of hydroxybenzoic acids. Polymers of high molecular weights (Mu = 78,000) with relatively narrow molecular weight distribution ( B J M , = 3.0) were prepared by reacting aromatic dicarboxylic acids with the adduct in pyridine, followed by addition of bisphenols. The polycondensation was significantly affected by the amount of DMF, the nature of the arylsulfonyl chlorides, the conditions of initial reaction of the acids with the adduct, and the rate of reaction with bisphenols. The process was adaptable to the direct polycondensation of hydroxybenzoic acids, affording polymers of high molecular weight (qinh = 1.73).

Pigmentation traits in adult Drosophila melanogaster were used in this study to investigate how phenotypic variations in continuous ecological traits can be maintained in a natural population. First, pigmentation variation in the adult female was measured at seven different body positions in 20 strains from the Drosophila melanogaster Genetic Reference Panel (DGRP) originating from a natural population in North Carolina. Next, to assess the contributions of cis-regulatory polymorphisms of the genes involved in the melanin biosynthesis pathway, allele-specific expression levels of four genes were quantified by amplicon sequencing using a 454 GS Junior. Among those genes, ebony was significantly associated with pigmentation intensity of the thoracic segment. Detailed sequence analysis of the gene regulatory regions of this gene indicated that many different functional cis-regulatory alleles are segregating in the population and that variations outside the core enhancer element could potentially play important roles in the regulation of gene expression. In addition, a slight enrichment of distantly associated SNP pairs was observed in the ~10 kb cis-regulatory region of ebony, which suggested the presence of interacting elements scattered across the region. In contrast, sequence analysis in the core cis-regulatory region of tan indicated that SNPs within the region are significantly associated with allele-specific expression level of this gene. Collectively, the data suggest that the underlying genetic differences in the cis-regulatory regions that control intraspecific pigmentation variation can be more complex than those of interspecific pigmentation trait differences, where causal genetic changes are typically confined to modular enhancer elements.

Pleiotropic genes are genes that affect more than one trait. For example, many genes required for pigmentation in the fruit fly Drosophila melanogaster also affect traits such as circadian rhythms, vision, and mating behavior. Here, we present evidence that two pigmentation genes, ebony and tan , which encode enzymes catalyzing reciprocal reactions in the melanin biosynthesis pathway, also affect cuticular hydrocarbon (CHC) composition in D. melanogaster females. More specifically, we report that ebony loss-of-function mutants have a CHC profile that is biased toward long (>25C) chain CHCs, whereas tan loss-of-function mutants have a CHC profile that is biased toward short (<25C) chain CHCs. Moreover, pharmacological inhibition of dopamine synthesis, a key step in the melanin synthesis pathway, reversed the changes in CHC composition seen in ebony mutants, making the CHC profiles similar to those seen in tan mutants. These observations suggest that genetic variation affecting ebony and/or tan activity might cause correlated changes in pigmentation and CHC composition in natural populations. We tested this possibility using the Drosophila Genetic Reference Panel (DGRP) and found that CHC composition covaried with pigmentation as well as levels of ebony and tan expression in newly eclosed adults in a manner consistent with the ebony and tan mutant phenotypes. These data suggest that the pleiotropic effects of ebony and tan might contribute to covariation of pigmentation and CHC profiles in Drosophila .

The spatiotemporal regulation of gene expression is essential to ensure robust phenotypic outcomes. Pigmentation patterns in Drosophila are determined by pigments biosynthesized in the developing epidermis and the cis-regulatory elements (CREs) of the genes involved in this process are well-characterized. Here we report that the known primary epidermal enhancer (priEE) is dispensable for the transcriptional activation of ebony (involved in light-colored pigment synthesis) in the developing epidermis of D. melanogaster. The evidence was obtained by introducing an approximately 1 kbp deletion at the priEE by genome editing. The effect of the priEE deletion on pigmentation and on the endogenous expression pattern of a mCherry-fused ebony allele was examined in the abdomen. The expression levels of the mCherry-fused ebony in the priEE-deleted strains were slightly higher than that of the control strain, indicating that the sequences outside the priEE have an ability to drive an expression of this gene in the epidermis. Interestingly, the priEE deletion resulted in a derepression of this gene in the dorsal midline of the abdominal tergites, where dark pigmentation is present in the wild-type individuals. This indicated that the priEE fragment contains a silencer. Furthermore, the endogenous expression pattern of ebony in the two additional strains with partially deleted priEE revealed that the silencer resides within a 351-bp fragment in the 5' portion of the priEE. These results demonstrated that deletion assays combined with reporter assays are highly effective in detecting the presence of positively and negatively regulating sequences within and outside the focal CREs.

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The Hoveyda–Grubbs (HG) second-generation catalyst (HG-II), a Ru complex with 2-isopropoxybenzylidene ligand, is extensively used for olefin metathesis, the rearrangement of carbon–carbon double bonds. A well-known strategy to control its...

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