Improved reference genome of Aedes aegypti informs arbovirus vector control

Female Aedes aegypti mosquitoes infect more than 400 million people each year with dangerous viral pathogens including dengue, yellow fever, Zika and chikungunya. Progress in understanding the biology of mosquitoes and developing the tools to fight them has been slowed by the lack of a high-quality genome assembly. Here we combine diverse technologies to produce the markedly improved, fully re-annotated AaegL5 genome assembly, and demonstrate how it accelerates mosquito science. We anchored physical and cytogenetic maps, doubled the number of known chemosensory ionotropic receptors that guide mosquitoes to human hosts and egg-laying sites, provided further insight into the size and composition of the sex-determining M locus, and revealed copy-number variation among glutathione S-transferase genes that are important for insecticide resistance. Using high-resolution quantitative trait locus and population genomic analyses, we mapped new candidates for dengue vector competence and insecticide resistance. AaegL5 will catalyse new biological insights and intervention strategies to fight this deadly disease vector

Investigating the Evolutionary Origins and Modification of Novel Morphologies and their Developmental Networks

The nature of the origin of morphological characters has long been a central subject of interest in the field of evolutionary developmental biology. Currently, many morphologies are known to be underscored by vast gene regulatory networks (GRNs) such that GRNs are anticipated for any feature of anatomy. Hence, if networks drive anatomical development, how do they evolve? The co-option of networks, a phenomenon in which cohorts of pre-existing transcriptional circuits are redeployed to new developmental settings, has been proposed to facilitate the rapid evolution of GRNs. Although several examples suggest the contribution of network co-option to the evolution of novel structures, examples that demonstrate and explore this process in molecular detail are currently lacking. In this dissertation I investigate the posterior lobe as a model of network co-option. A cuticular outgrowth on the genitalia of male fruit flies, this morphology is unique to the Drosophila melanogaster clade. By studying the ancestry of one gene’s posterior lobe activity, I discovered that it existed before the evolution of the posterior lobe, and had been redeployed from a network active during embryonic life. I next investigate the origin of the posterior lobe by studying the intercellular signaling pathways that contribute to its specification, discovering that a drastically altered pattern of the Notch ligand Delta is necessary for the development and evolution of the posterior lobe. I then explore how an embryonic circuit that was co-opted to the posterior lobe was subsequently modified to alter its shape. Finally, I study the origins of novelty at the level of an individual transcriptional circuit, analyzing all possible intermediate states along its evolutionary path. These studies demonstrate the value of an approach focused on understanding the co-option and origination of regulatory circuitry for the study of the evolution of novel characters

Defining the characteristics and expectations of fluid bolus therapy: A worldwide perspective

Purpose: The purpose of the study is to understand what clinicians believe defines fluid bolus therapy (FBT) and the expected response to such intervention. Methods: We asked intensive care specialists in 30 countries to participate in an electronic questionnaire of their practice, definition, and expectations of FBT. Results: We obtained 3138 responses. Despite much variation, more than 80% of respondents felt that more than 250 mL of either colloid or crystalloid fluid given over less than 30 minutes defined FBT, with crystalloids most acceptable. The most acceptable crystalloid and colloid for use as FBT were 0.9% saline and 4% albumin solution, respectively. Most respondents believed that one or more of the following physiological changes indicates a response to FBT: a mean arterial pressure increase greater than 10 mm Hg, a heart rate decrease greater than 10 beats per minute, an increase in urinary output by more than 10 mL/h, an increase in central venous oxygen saturation greater than 4%, or a lactate decrease greater than 1 mmol/L. Conclusions: Despite wide variability between individuals and countries, clear majority views emerged to describe practice, define FBT, and identify a response to it. Further investigation is now required to describe actual FBT practice and to identify the magnitude and duration of the physiological response to FBT and its relationship to patient-centered outcomes. (C) 2016 Elsevier Inc. All rights reserved

Semaphorin-Plexin Signaling: From Axonal Guidance to a New X-Linked Intellectual Disability Syndrome

Background: Semaphorins and plexins are ligands and cell surface receptors that regulate multiple neurodevelopmental processes such as axonal growth and guidance. PLXNA3 is a plexin gene located on the X chromosome that encodes the most widely expressed plexin receptor in fetal brain, plexin-A3. Plexin-A3 knockout mice demonstrate its role in semaphorin signaling in vivo. The clinical manifestations of semaphorin/plexin neurodevelopmental disorders have been less widely explored. This study describes the neurological and neurodevelopmental phenotypes of boys with maternally inherited hemizygous PLXNA3 variants. Methods: Data-sharing through GeneDx and GeneMatcher allowed identification of individuals with autism or intellectual disabilities (autism/ID) and hemizygous PLXNA3 variants in collaboration with their physicians and genetic counselors, who completed questionnaires about their patients. In silico analyses predicted pathogenicity for each PLXNA3 variant. Results: We assessed 14 boys (mean age, 10.7 [range 2 to 25] years) with maternally inherited hemizygous PLXNA3 variants and autism/ID ranging from mild to severe. Other findings included fine motor dyspraxia (92%), attention-deficit/hyperactivity traits, and aggressive behaviors (63%). Six patients (43%) had seizures. Thirteen boys (93%) with PLXNA3 variants showed novel or very low allele frequencies and probable damaging/disease-causing pathogenicity in one or more predictors. We found a genotype-phenotype correlation between PLXNA3 cytoplasmic domain variants (exons 22 to 32) and more severe neurodevelopmental disorder phenotypes (P < 0.05). Conclusions: We report 14 boys with maternally inherited, hemizygous PLXNA3 variants and a range of neurodevelopmental disorders suggesting a novel X-linked intellectual disability syndrome. Greater understanding of PLXNA3 variant pathogenicity in humans will require additional clinical, computational, and experimental validation

Improved Aedes aegypti mosquito reference genome assembly enables biological discovery and vector control

Female Aedes aegypti mosquitoes infect hundreds of millions of people each year with dangerous viral pathogens including dengue, yellow fever, Zika, and chikungunya. Progress in understanding the biology of this insect, and developing tools to fight it, has been slowed by the lack of a high-quality genome assembly. Here we combine diverse genome technologies to produce AaegL5, a dramatically improved and annotated assembly, and demonstrate how it accelerates mosquito science and control. We anchored the physical and cytogenetic maps, resolved the size and composition of the elusive sex-determining M locus, significantly increased the known members of the glutathione-S-transferase genes important for insecticide resistance, and doubled the number of chemosensory ionotropic receptors that guide mosquitoes to human hosts and egg-laying sites. Using high-resolution QTL and population genomic analyses, we mapped new candidates for dengue vector competence and insecticide resistance. We predict that AaegL5 will catalyse new biological insights and intervention strategies to fight this deadly arboviral vector