Functional insights from the GC-poor genomes of two aphid parasitoids, Aphidius ervi and Lysiphlebus fabarum.

Parasitoid wasps have fascinating life cycles and play an important role in trophic networks, yet little is known about their genome content and function. Parasitoids that infect aphids are an important group with the potential for biological control. Their success depends on adapting to develop inside aphids and overcoming both host aphid defenses and their protective endosymbionts. We present the de novo genome assemblies, detailed annotation, and comparative analysis of two closely related parasitoid wasps that target pest aphids: Aphidius ervi and Lysiphlebus fabarum (Hymenoptera: Braconidae: Aphidiinae). The genomes are small (139 and 141 Mbp) and the most AT-rich reported thus far for any arthropod (GC content: 25.8 and 23.8%). This nucleotide bias is accompanied by skewed codon usage and is stronger in genes with adult-biased expression. AT-richness may be the consequence of reduced genome size, a near absence of DNA methylation, and energy efficiency. We identify missing desaturase genes, whose absence may underlie mimicry in the cuticular hydrocarbon profile of L. fabarum. We highlight key gene groups including those underlying venom composition, chemosensory perception, and sex determination, as well as potential losses in immune pathway genes. These findings are of fundamental interest for insect evolution and biological control applications. They provide a strong foundation for further functional studies into coevolution between parasitoids and their hosts. Both genomes are available at https://bipaa.genouest.org

Continued Neurogenesis in Adult Drosophila as a Mechanism for Recruiting Environmental Cue-Dependent Variants

Background The skills used by winged insects to explore their environment are strongly dependent upon the integration of neurosensory information comprising visual, acoustic and olfactory signals. The neuronal architecture of the wing contains a vast array of different sensors which might convey information to the brain in order to guide the trajectories during flight. In Drosophila, the wing sensory cells are either chemoreceptors or mechanoreceptors and some of these sensors have as yet unknown functions. The axons of these two functionally distinct types of neurons are entangled, generating a single nerve. This simple and accessible coincidental signaling circuitry in Drosophila constitutes an excellent model system to investigate the developmental variability in relation to natural behavioral polymorphisms. Methodology/Principal Findings A fluorescent marker was generated in neurons at all stages of the Drosophila life cycle using a highly efficient and controlled genetic recombination system that can be induced in dividing precursor cells (MARCM system, flybase web site). It allows fluorescent signals in axons only when the neuroblasts and/or neuronal cell precursors like SOP (sensory organ precursors) undergo division during the precedent steps. We first show that a robust neurogenesis continues in the wing after the adults emerge from the pupae followed by an extensive axonal growth. Arguments are presented to suggest that this wing neurogenesis in the newborn adult flies was influenced by genetic determinants such as the frequency dependent for gene and by environmental cues such as population density. Conclusions We demonstrate that the neuronal architecture in the adult Drosophila wing is unfinished when the flies emerge from their pupae. This unexpected developmental step might be crucial for generating non-heritable variants and phenotypic plasticity. This might therefore constitute an advantage in an unstable ecological system and explain much regarding the ability of Drosophila to robustly adapt to their environment

Serum levels of Clara cell secretory protein, asthma, and lung function in the adult general population.

Clara cell secretory protein (CC-16) has anti-inflammatory properties and protective effects from oxidative stress on the respiratory tract and has been proposed as a biological marker of lung epithelial injury and pulmonary permeability. In this study, we evaluated serum CC-16 level as a biomarker relevant in the study of asthma and lung function phenotypes in adults from the Spanish branch of the population-based multicenter European Community Respiratory Health Survey.We measured CC-16 in serum samples of 859 participants (mean age 41 yrs; 51% women) of 3 Spanish ECRHS centers using an immunoassay. Current asthma, airflow limitation (AL) and lung function parameters (FEV1% and FVC% predicted and FEV1/FVC ratio) were considered. All estimates were adjusted for centre, type of sample, sex, age, smoking, pack-years, body mass index (BMI), and height. Mean serum CC-16 levels were 5.8 \ub1 2.9 \u3bcg/L, ranging from 0.37 to 19.7 \u3bcg/L. Serum CC-16 levels did not vary with current asthma in the total population. However, lower serum CC-16 levels were associated with current asthma among never smokers. Reduced CC-16 levels were associated with AL (OR=0.71, P=0.03) and with moderate severe COPD stages (RRR=0.52, P=0.01 vs no AL). CC-16 level increased with FEV1% predicted (beta=1.92, p<0.001) and FEV1/FVC (beta=0.84, p<0.001) and was borderline significant for FVC% predicted (beta=0.84, P=0.06).In summary, we found reduced serum CC-16 levels to be associated with airflow limitation and lower lung function in the general population after adjusting for the effects of cigarette smoking and other covariates. These data warrant evaluation of serum CC-16 level as a potential biomarker of lung function deficits and obstructive lung disease in the longitudinal setting