25 research outputs found
The technique of comedy in the novels of Jane Austen
This study of the comic technique of Jane Austen emphasises the social and moral basis of her comedy and begins with a chapter on an analysis of her values. It then proceeds to look at various aspects of her comic technique, namely, her comic characters, her comic situations and her comic voice. The second chapter distinguishes two main categories of comic characters: the 'comic fools,' usually the minor characters, unaware, undiscerning and often consistently comic, and the major comic characters, intelligent, perceptive and only comic at some points when they make mistakes of judgment and perception. The chapter concentrates on both the content and form of these characters, drawing illustrations from as many of the novels as possible. The third chapter traces the author's progress from the farcical and often unsubtle comic situations of the early works to the complex comic situations of the mature novels in which character and incident are much better co-ordinated. The chapter on the author's comic voice discusses the various devices by which Jane Austen makes her comic presence felt in her novels, and the final chapter examines the unfinished work Sanditon, pointing out new comic tendencies and tentatively suggesting that it might have been a different kind of comic novel.<p
Pyrimidine biosynthesis is not an essential function for trypanosoma brucei bloodstream forms
<p>Background: African trypanosomes are capable of both pyrimidine biosynthesis and salvage of preformed pyrimidines from the host, but it is unknown whether either process is essential to the parasite.</p>
<p>Methodology/Principal Findings: Pyrimidine requirements for growth were investigated using strictly pyrimidine-free media, with or without single added pyrimidine sources. Growth rates of wild-type bloodstream form Trypanosoma brucei brucei were unchanged in pyrimidine-free medium. The essentiality of the de novo pyrimidine biosynthesis pathway was studied by knocking out the PYR6-5 locus that produces a fusion product of orotate phosphoribosyltransferase (OPRT) and Orotidine Monophosphate Decarboxylase (OMPDCase). The pyrimidine auxotroph was dependent on a suitable extracellular pyrimidine source. Pyrimidine starvation was rapidly lethal and non-reversible, causing incomplete DNA content in new cells. The phenotype could be rescued by addition of uracil; supplementation with uridine, 2′deoxyuridine, and cytidine allowed a diminished growth rate and density. PYR6-5−/− trypanosomes were more sensitive to pyrimidine antimetabolites and displayed increased uracil transport rates and uridine phosphorylase activity. Pyrimidine auxotrophs were able to infect mice although the infection developed much more slowly than infection with the parental, prototrophic trypanosome line.</p>
<p>Conclusions/Significance: Pyrimidine salvage was not an essential function for bloodstream T. b. brucei. However, trypanosomes lacking de novo pyrimidine biosynthesis are completely dependent on an extracellular pyrimidine source, strongly preferring uracil, and display reduced infectivity. As T. brucei are able to salvage sufficient pyrimidines from the host environment, the pyrimidine biosynthesis pathway is not a viable drug target, although any interruption of pyrimidine supply was lethal.</p>
The genomic landscape of balanced cytogenetic abnormalities associated with human congenital anomalies
Despite the clinical significance of balanced chromosomal abnormalities (BCAs), their characterization has largely been restricted to cytogenetic resolution. We explored the landscape of BCAs at nucleotide resolution in 273 subjects with a spectrum of congenital anomalies. Whole-genome sequencing revised 93% of karyotypes and demonstrated complexity that was cryptic to karyotyping in 21% of BCAs, highlighting the limitations of conventional cytogenetic approaches. At least 33.9% of BCAs resulted in gene disruption that likely contributed to the developmental phenotype, 5.2% were associated with pathogenic genomic imbalances, and 7.3% disrupted topologically associated domains (TADs) encompassing known syndromic loci. Remarkably, BCA breakpoints in eight subjects altered a single TAD encompassing MEF2C, a known driver of 5q14.3 microdeletion syndrome, resulting in decreased MEF2C expression. We propose that sequence-level resolution dramatically improves prediction of clinical outcomes for balanced rearrangements and provides insight into new pathogenic mechanisms, such as altered regulation due to changes in chromosome topology