Genetic Contributions of desatF and eloF to Courtship Mating Behavior and Cuticular Hydrocarbon Production in Drosophila simulans and D. sechellia

Sexual isolation occurs between Drosophila simulans and D. sechellia due to differences in cuticular hydrocarbon (CHC) productions. A wide variety of hydrocarbons are produced, but D. simulans males and females predominantly produce 7-tricosene (7-T), a 23 carbon monoene, while D. sechellia males produce 7-T and D. sechellia females produce 7,11-heptacosadiene (7,11-HD), a 27 carbon diene (Coyne et al. 1994). An asymmetric mating pattern occurs due to hydrocarbon differences: D. simulans males only court D. simulans females and D. sechellia males court both D. simulans and D. sechellia females (Cobb and Jallon 1990). Previous quantitative trait locus (QTL) studies (Gleason et al. 2005; Gleason et al. 2009) identified desatF and eloF as candidate genes contributing to production of D. sechellia pheromone 7,11-HD. In this thesis, the effect of D. sechellia alleles in a D. simulans background is measured for desatF and eloF by (1) monitoring mating behavior response through copulation success and latency and (2) identifying the differences in CHC biosynthesis through elongation and desaturation changes. Behavioral analyses indicated that there was no significant effect on courtship for the genes independently. Analysis of CHC production differences indicates a more pronounced effect of desatF and eloF on pheromone biosynthesis. In elongation from 23 to 25 carbons, females carrying the eloF gene produced increased amounts of 7-pentacosene, indicating eloF effects hydrocarbon elongation. Absence of further elongation to 27 carbons suggests involvement of other elongases for synthesis to 7,11-HD. Females carrying the desatF gene produced increased amounts of 7,11-pentacosadiene, indicating desatF is responsible for increasing dienes. Only when females carried D. sechellia alleles at both loci did production of 7,11-HD occur. However, the amount of 7,11-HD was significantly lower than amounts produced by D. sechellia females. Evidence from this study indicates desatF and eloF are genes present in the hydrocarbon biosynthesis pathway and are probably necessary for female D. sechellia pheromone production. However, D. sechellia alleles of desatF and eloF are not sufficient for production of 7,11-HD indicating involvement of other biosynthesis genes to fully produce the D. sechellia female pheromone

AN EXAMINATION OF THE IMPACT TRAUMATIC EVENTS HAS ON PSYCHOSOCIAL IMPAIRMENT IN EATING DISORDER PATIENTS

Research suggests that trauma has an impact on eating disorders. While prior research has demonstrated that the trauma from abuse has a significant impact on eating disorders, research has failed to explore other types of trauma. In addition, previous studies have stopped short of examining the impact trauma has on functioning among individuals with an eating disorder. This study aimed to address that gap in the literature. The purpose of this study is to examine whether traumatic life events impact psychosocial functioning among individuals living with an eating disorder. Furthermore, this study aimed to identify which traumas are shown to have the strongest impact on psychosocial functioning. A quantitative design was used for this investigation, using measurement scales that have been shown to be valid and reliable in measuring the constructs of trauma and psychosocial functioning among individuals with an eating disorder. Participants completed a single survey of the combined measurement scales. A non-random purposive sample was collected from online social media cites Tumblr, Facebook, eating disorder message boards, and an outpatient eating disorder treatment center. Using a study sample of N= 2,319 descriptive and inferential statistics were conducted using SPSS. Based on the results of correlation and multiple regression analyses, a statistically significant relationship was found between traumatic life events and psychosocial impairment among those with eating disorders. The findings of this study have the potential to impact the way social work policies address the relationship between trauma and eating disorders, and influence the way social work clinicians implement strategies to treat both trauma and eating psychopathology

Parametric polymorphism and operational improvement

Parametricity, in both operational and denotational forms, has long been a useful tool for reasoning about program correctness. However, there is as yet no comparable technique for reasoning about program improvement, that is, when one program uses fewer resources than another. Existing theories of parametricity cannot be used to address this problem as they are agnostic with regard to resource usage. This article addresses this problem by presenting a new operational theory of parametricity that is sensitive to time costs, which can be used to reason about time improvement properties. We demonstrate the applicability of our theory by showing how it can be used to prove that a number of well-known program fusion techniques are time improvements, including fixed point fusion, map fusion and short cut fusion

Worker/wrapper/makes it/faster

Much research in program optimization has focused on formal approaches to correctness: proving that the meaning of programs is preserved by the optimisation. Paradoxically, there has been comparatively little work on formal approaches to efficiency: proving that the performance of optimized programs is actually improved. This paper addresses this problem for a general-purpose optimization technique, the worker/wrapper transformation. In particular, we use the call-by-need variant of improvement theory to establish conditions under which the worker/wrapper transformation is formally guaranteed to preserve or improve the time performance of programs in lazy languages such as Haskell

Programs for cheap!

Write down the definition of a recursion operator on a piece of paper. Tell me its type, but be careful not to let me see the operator’s definition. I will tell you an optimization theorem that the operator satisfies. As an added bonus, I will also give you a proof of correctness for the optimisation, along with a formal guarantee about its effect on performance. The purpose of this paper is to explain these tricks

The under-performing unfold: a new approach to optimising corecursive programs

This paper presents a new approach to optimising corecursive programs by factorisation. In particular, we focus on programs written using the corecursion operator unfold. We use and expand upon the proof techniques of guarded coinduction and unfold fusion, capturing a pattern of generalising coinductive hypotheses by means of abstraction and representation functions. The pattern we observe is simple, has not been observed before, and is widely applicable. We develop a general program factorisation theorem from this pattern, demonstrating its utility with a range of practical examples

The under-performing unfold: a new approach to optimising corecursive programs

This paper presents a new approach to optimising corecursive programs by factorisation. In particular, we focus on programs written using the corecursion operator unfold. We use and expand upon the proof techniques of guarded coinduction and unfold fusion, capturing a pattern of generalising coinductive hypotheses by means of abstraction and representation functions. The pattern we observe is simple, has not been observed before, and is widely applicable. We develop a general program factorisation theorem from this pattern, demonstrating its utility with a range of practical examples

Transcriptome analysis reveals nuclear-encoded proteins for the maintenance of temporary plastids in the dinoflagellate Dinophysis acuminata

<p>Abstract</p> <p>Background</p> <p><it>Dinophysis </it>is exceptional among dinoflagellates, possessing plastids derived from cryptophyte algae. Although <it>Dinophysis </it>can be maintained in pure culture for several months, the genus is mixotrophic and needs to feed either to acquire plastids (a process known as kleptoplastidy) or obtain growth factors necessary for plastid maintenance. <it>Dinophysis </it>does not feed directly on cryptophyte algae, but rather on a ciliate (<it>Myrionecta rubra</it>) that has consumed the cryptophytes and retained their plastids. Despite the apparent absence of cryptophyte nuclear genes required for plastid function, <it>Dinophysis </it>can retain cryptophyte plastids for months without feeding.</p> <p>Results</p> <p>To determine if this dinoflagellate has nuclear-encoded genes for plastid function, we sequenced cDNA from <it>Dinophysis acuminata</it>, its ciliate prey <it>M. rubra</it>, and the cryptophyte source of the plastid <it>Geminigera cryophila</it>. We identified five proteins complete with plastid-targeting peptides encoded in the nuclear genome of <it>D. acuminata </it>that function in photosystem stabilization and metabolite transport. Phylogenetic analyses show that the genes are derived from multiple algal sources indicating some were acquired through horizontal gene transfer.</p> <p>Conclusions</p> <p>These findings suggest that <it>D. acuminata </it>has some functional control of its plastid, and may be able to extend the useful life of the plastid by replacing damaged transporters and protecting components of the photosystem from stress. However, the dearth of plastid-related genes compared to other fully phototrophic algae suggests that <it>D. acuminata </it>does not have the nuclear repertoire necessary to maintain the plastid permanently.</p

The worker-wrapper transformation: getting it right and making it better

A program optimisation must have two key properties: it must preserve the meaning of programs (correctness) while also making them more efficient (improvement). An optimisation's correctness can often be rigorously proven using formal mathematical methods, but improvement is generally considered harder to prove formally and is thus typically demonstrated with empirical techniques such as benchmarking. The result is a conspicuous ``reasoning gap'' between correctness and efficiency. In this thesis, we focus on a general-purpose optimisation: the worker\slash wrapper transformation. We develop a range of theories for establishing correctness and improvement properties of this transformation that all share a common structure. Our development culminates in a single theory that can be used to reason about both correctness and efficiency in a unified manner, thereby bridging the reasoning gap

Horizontal gene transfer is a significant driver of gene innovation in dinoflagellates

© The Author(s), 2013. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Genome Biology and Evolution 5 (2013): 2368-2381, doi:10.1093/gbe/evt179.The dinoflagellates are an evolutionarily and ecologically important group of microbial eukaryotes. Previous work suggests that horizontal gene transfer (HGT) is an important source of gene innovation in these organisms. However, dinoflagellate genomes are notoriously large and complex, making genomic investigation of this phenomenon impractical with currently available sequencing technology. Fortunately, de novo transcriptome sequencing and assembly provides an alternative approach for investigating HGT. We sequenced the transcriptome of the dinoflagellate Alexandrium tamarense Group IV to investigate how HGT has contributed to gene innovation in this group. Our comprehensive A. tamarense Group IV gene set was compared with those of 16 other eukaryotic genomes. Ancestral gene content reconstruction of ortholog groups shows that A. tamarense Group IV has the largest number of gene families gained (314–1,563 depending on inference method) relative to all other organisms in the analysis (0–782). Phylogenomic analysis indicates that genes horizontally acquired from bacteria are a significant proportion of this gene influx, as are genes transferred from other eukaryotes either through HGT or endosymbiosis. The dinoflagellates also display curious cases of gene loss associated with mitochondrial metabolism including the entire Complex I of oxidative phosphorylation. Some of these missing genes have been functionally replaced by bacterial and eukaryotic xenologs. The transcriptome of A. tamarense Group IV lends strong support to a growing body of evidence that dinoflagellate genomes are extraordinarily impacted by HGT.J.H.W. was supported by the NSF IGERT Program in Comparative Genomics at the University of Arizona (grant number DGE-0654435). This work was supported by grants from the National Science Foundation (grant numbers OCE-0723498, EF-0732440) and funding provided by the BIO5 Institute at the University of Arizona to J.D.H