Prolonged dehydration resistance by the northern house mosquito, Culex pipiens, during its overwintering diapause

Throughout the winter, the northern house mosquito, Culex pipiens, is continually exposed to desiccating conditions, and this water deficit is further exacerbated by long periods with no access to free water. In this study, we report that mosquitoes in diapause are more tolerant of xeric conditions than their nondiapausing counterparts. To counter water loss female mosquitoes reared under conditions that induce diapause have a lower percent water content that results from a higher dry mass which in turn decreases their surface area to volume ratio. Both diapausing and nondiapausing females can tolerate a loss of approximately 30%, but diapausing females conserve their water reserves more do not reach this limit as readily. This mosquito relies solely on drinking free water to replenish its water supply and has no ability to absorb water vapor from the atmosphere. Cuticular hydrocarbon content was nearly 3x higher in diapausing female mosquitoes than nondiapausing individuals, this enhancement impedes water loss through the cuticle. No differences were noted in sorbitol, trehalose, glycerol or the total sugar contents during diapause. Additionally, the utilization on internal lipids by diapausing C. pipiens was significantly lower than nondiapausing female. Thus, the increased dehydration resistance of diapausing females C. pipiens results from the combination of their larger size, accumulation of additional cuticular lipids, and a suppression of metabolism

The Spermatophore in Glossina morsitans morsitans: Insights into Male Contributions to Reproduction.

Male Seminal Fluid Proteins (SFPs) transferred during copulation modulate female reproductive physiology and behavior, impacting sperm storage/use, ovulation, oviposition, and remating receptivity. These capabilities make them ideal targets for developing novel methods of insect disease vector control. Little is known about the nature of SFPs in the viviparous tsetse flies (Diptera: Glossinidae), vectors of Human and Animal African trypanosomiasis. In tsetse, male ejaculate is assembled into a capsule-like spermatophore structure visible post-copulation in the female uterus. We applied high-throughput approaches to uncover the composition of the spermatophore in Glossina morsitans morsitans. We found that both male accessory glands and testes contribute to its formation. The male accessory glands produce a small number of abundant novel proteins with yet unknown functions, in addition to enzyme inhibitors and peptidase regulators. The testes contribute sperm in addition to a diverse array of less abundant proteins associated with binding, oxidoreductase/transferase activities, cytoskeletal and lipid/carbohydrate transporter functions. Proteins encoded by female-biased genes are also found in the spermatophore. About half of the proteins display sequence conservation relative to other Diptera, and low similarity to SFPs from other studied species, possibly reflecting both their fast evolutionary pace and the divergent nature of tsetse's viviparous biology

A quick guide for student-driven community genome annotation

High quality gene models are necessary to expand the molecular and genetic tools available for a target organism, but these are available for only a handful of model organisms that have undergone extensive curation and experimental validation over the course of many years. The majority of gene models present in biological databases today have been identified in draft genome assemblies using automated annotation pipelines that are frequently based on orthologs from distantly related model organisms. Manual curation is time consuming and often requires substantial expertise, but is instrumental in improving gene model structure and identification. Manual annotation may seem to be a daunting and cost-prohibitive task for small research communities but involving undergraduates in community genome annotation consortiums can be mutually beneficial for both education and improved genomic resources. We outline a workflow for efficient manual annotation driven by a team of primarily undergraduate annotators. This model can be scaled to large teams and includes quality control processes through incremental evaluation. Moreover, it gives students an opportunity to increase their understanding of genome biology and to participate in scientific research in collaboration with peers and senior researchers at multiple institutions

Activation of HuR downstream of p38 MAPK promotes cardiomyocyte hypertrophy

The RNA binding protein Human antigen R (HuR) interacts with specific AU-rich domains in target mRNAs and is highly expressed in many cell types, including cardiomyocytes. However, the role of HuR in cardiac physiology is largely unknown. Our results show that HuR undergoes cytoplasmic translocation, indicative of its activation, in hypertrophic cardiac myocytes. Specifically, HuR cytoplasmic translocation is significantly increased in NRVMs (neonatal rat ventricular myocytes) following treatment with phenylephrine or angiotensin II, agonists of two independent Gαq-coupled GPCRs known to induce hypertrophy. This Gq-mediated HuR activation is dependent on p38 MAP kinase, but not canonical Gq-PKC signaling. Furthermore, we show that HuR activation is necessary for Gq-mediated hypertrophic growth of NRVMs as siRNA-mediated knockdown of HuR inhibits hypertrophy as measured by cell size and expression of ANF (atrial natriuretic factor). Additionally, HuR overexpression is sufficient to induce hypertrophic cell growth. To decipher the downstream mechanisms by which HuR translocation promotes cardiomyocyte hypertrophy, we assessed the role of HuR in the transcriptional activity of NFAT (nuclear factor of activated T cells), the activation of which is a hallmark of cardiac hypertrophy. Using an NFAT-luciferase reporter assay, we show an acute inhibition of NFAT transcriptional activity following pharmacological inhibition of HuR. In conclusion, our results identify HuR as a novel mediator of cardiac hypertrophy downstream of the Gq-p38 MAPK pathway, and suggest modulation of NFAT activity as a potential mechanism

SERG Final report: Ecosystemic impacts of forest tent caterpillar outbreaks

The forest tent caterpillar (Malacosoma disstria) is a significant defoliator of hardwoods throughout Canada. Historically, infestations usually collapsed after one or two years of defoliation, but longer and more severe outbreaks have been observed in recent years, leading to mortality of both sugar maple and trembling aspen, and making the forest tent caterpillar another pest whose impacts are increasing under a changing climate. This project examines how forest tent caterpillar outbreaks influence soil ecosystems, in both temperate deciduous and mixed boreal forests. We will assess inputs to soil ecosystems associated with forest tent caterpillar outbreaks and determine impacts on soil arthropod communities and tree regeneration. We also examine the different sources of mortality of the forest tent caterpillar colonies during and after the outbreak. It will thus provide empirical data to assess effects of forest tent caterpillar outbreaks on forest ecosystems and successional processes as well as population dynamics throughout the outbreaking cycle. Results suggest that defoliation favours the growth of non-host saplings. They also suggest that sources of mortality change during the different parts of the outbreak. Results will also contribute to the development of novel silvicultural approaches taking into account the effects of forest tent caterpillar outbreaks on forest regeneration and the need to keep process promoting regulation of forest tent caterpillar populations. La livrée des forêts (Malacosoma disstria) est un défoliateur important des forêts feuillues du Canada. Dans le passé, les épidémies s’effondraient généralement après une ou deux années de défoliation sans causer de dommages significatifs à la forêt, mais l’observation récente d’épidémies plus longues et plus sévères, suivies de mortalité des tiges de peuplier faux-tremble et d’érable à sucre, suggèrent que les impacts de la livrée des forêts, comme de plusieurs autres insectes ravageurs, augmentent en raison des changements climatiques. Ce projet examine les effets d’une épidémie de livrée des forêts sur l’écosystème du sol dans deux écosystèmes forestiers: la forêt feuillue et la forêt boréale mixte. Nous examinerons les apports en nutriments au sol associés aux épidémies de livrée et évaluerons les effets sur la communauté d’arthropodes du sol et sur la régénération des arbres. Nous avons aussi examiné les sources de mortalité des colonies de livrée des forêts durant et après l’épidémie. Les résultats fourniront des données empiriques pour évaluer les impacts des épidémies de livrée sur les écosystèmes forestiers et les processus de succession écologiques ainsi que les dynamiques de populations à travers les cycles épidémiques. Les résultats suggèrent que la défoliation peut bénéficier la croissance des jeunes arbres non-hôtes. Ils suggèrent aussi que les sources de mortalité diffèrent lors des différentes parties du cycles épidémiques. Les résultats contribueront aussi au développement d’approches sylvicoles qui prennent en considération le rôle de la livrée dans la régénération des forêts

STS-k: A Multilevel Sparse Triangular Solution Scheme for NUMA Multicores

We consider techniques to improve the performance of parallel sparse triangular solution on non-uniform memory architecture multicores by extending earlier coloring and level set schemes for single-core multiprocessors. We develop sts-k, where k represents a small number of transformations for latency reduction from increased spatial and temporal locality of data accesses. We propose a graph model of data reuse to inform the development of sts-k and to prove that computing an optimal cost schedule is NP-complete. We observe significant speed-ups with sts-3 on 32-core Intel Westmere-EX and 24-core AMD `MagnyCours' processors.Incremental gains solely from the 3-level transformations in sts-3 for a fixed ordering, correspond to reductions in execution times by factors of 1.4 (Intel) and 1.5 (AMD) for level sets and 2 (Intel) and 2.2 (AMD) for coloring. On average, execution times are reduced by a factor of 6 (Intel) and 4 (AMD) for sts-3 with coloring compared to a reference implementation using level sets