Caenorhabditis elegans: a model to monitor bacterial air quality

<p>Abstract</p> <p>Background</p> <p>Low environmental air quality is a significant cause of mortality and morbidity and this question is now emerging as a main concern of governmental authorities. Airborne pollution results from the combination of chemicals, fine particles, and micro-organisms quantitatively or qualitatively dangerous for health or for the environment. Increasing regulations and limitations for outdoor air quality have been decreed in regards to chemicals and particles contrary to micro-organisms. Indeed, pertinent and reliable tests to evaluate this biohazard are scarce. In this work, our purpose was to evaluate the <it>Caenorhaditis elegans </it>killing test, a model considered as an equivalent to the mouse acute toxicity test in pharmaceutical industry, in order to monitor air bacterial quality.</p> <p>Findings</p> <p>The present study investigates the bacterial population in dust clouds generated during crop ship loading in harbor installations (Rouen harbor, Normandy, France). With a biocollector, airborne bacteria were impacted onto the surface of agar medium. After incubation, a replicate of the colonies on a fresh agar medium was done using a velvet. All the replicated colonies were pooled creating the "Total Air Sample". Meanwhile, all the colonies on the original plate were isolated. Among which, five representative bacterial strains were chosen. The virulence of these representatives was compared to that of the "Total Air Sample" using the <it>Caenorhaditis elegans </it>killing test. The survival kinetic of nematodes fed with the "Total Air Sample" is consistent with the kinetics obtained using the five different representatives strains.</p> <p>Conclusions</p> <p>Bacterial air quality can now be monitored in a one shot test using the <it>Caenorhaditis elegans </it>killing test.</p

Retention of Memory through Metamorphosis: Can a Moth Remember What It Learned As a Caterpillar?

Insects that undergo complete metamorphosis experience enormous changes in both morphology and lifestyle. The current study examines whether larval experience can persist through pupation into adulthood in Lepidoptera, and assesses two possible mechanisms that could underlie such behavior: exposure of emerging adults to chemicals from the larval environment, or associative learning transferred to adulthood via maintenance of intact synaptic connections. Fifth instar Manduca sexta caterpillars received an electrical shock associatively paired with a specific odor in order to create a conditioned odor aversion, and were assayed for learning in a Y choice apparatus as larvae and again as adult moths. We show that larvae learned to avoid the training odor, and that this aversion was still present in the adults. The adult aversion did not result from carryover of chemicals from the larval environment, as neither applying odorants to naïve pupae nor washing the pupae of trained caterpillars resulted in a change in behavior. In addition, we report that larvae trained at third instar still showed odor aversion after two molts, as fifth instars, but did not avoid the odor as adults, consistent with the idea that post-metamorphic recall involves regions of the brain that are not produced until later in larval development. The present study, the first to demonstrate conclusively that associative memory survives metamorphosis in Lepidoptera, provokes intriguing new questions about the organization and persistence of the central nervous system during metamorphosis. Our results have both ecological and evolutionary implications, as retention of memory through metamorphosis could influence host choice by polyphagous insects, shape habitat selection, and lead to eventual sympatric speciation

Characterizing the scent and chemical composition of Panthera leo marking fluid using solid-phase microextraction and multidimensional gas chromatography–mass spectrometry-olfactometry

Lions (Panthera leo) use chemical signaling to indicate health, reproductive status, and territorial ownership. To date, no study has reported on both scent and composition of marking fluid (MF) from P. leo. The objectives of this study were to: 1) develop a novel method for simultaneous chemical and scent identification of lion MF in its totality (urine + MF), 2) identify characteristic odorants responsible for the overall scent of MF as perceived by human panelists, and 3) compare the existing library of known odorous compounds characterized as eliciting behaviors in animals in order to understand potential functionality in lion behavior. Solid-phase microextraction and simultaneous chemical-sensory analyses with multidimensional gas-chromatography-mass spectrometry-olfactometry improved separating, isolating, and identifying mixed (MF, urine) compounds versus solvent-based extraction and chemical analyses. 2,5-Dimethylpyrazine, 4-methylphenol, and 3-methylcyclopentanone were isolated and identified as the compounds responsible for the characteristic odor of lion MF. Twenty-eight volatile organic compounds (VOCs) emitted from MF were identified, adding a new list of compounds previously unidentified in lion urine. New chemicals were identified in nine compound groups: ketones, aldehydes, amines, alcohols, aromatics, sulfur-containing compounds, phenyls, phenols, and volatile fatty acids. Twenty-three VOCs are known semiochemicals that are implicated in attraction, reproduction, and alarm-signaling behaviors in other species

Climate Change, Coral Reef Ecosystems, and Management Options for Marine Protected Areas

Marine protected areas (MPAs) provide place-based management of marine ecosystems through various degrees and types of protective actions. Habitats such as coral reefs are especially susceptible to degradation resulting from climate change, as evidenced by mass bleaching events over the past two decades. Marine ecosystems are being altered by direct effects of climate change including ocean warming, ocean acidification, rising sea level, changing circulation patterns, increasing severity of storms, and changing freshwater influxes. As impacts of climate change strengthen they may exacerbate effects of existing stressors and require new or modified management approaches; MPA networks are generally accepted as an improvement over individual MPAs to address multiple threats to the marine environment. While MPA networks are considered a potentially effective management approach for conserving marine biodiversity, they should be established in conjunction with other management strategies, such as fisheries regulations and reductions of nutrients and other forms of land-based pollution. Information about interactions between climate change and more “traditional” stressors is limited. MPA managers are faced with high levels of uncertainty about likely outcomes of management actions because climate change impacts have strong interactions with existing stressors, such as land-based sources of pollution, overfishing and destructive fishing practices, invasive species, and diseases. Management options include ameliorating existing stressors, protecting potentially resilient areas, developing networks of MPAs, and integrating climate change into MPA planning, management, and evaluation

The effect of syllable variation on the perception of lexical tones in Cantonese-speaking amusics

9th International Conference on Speech Prosody 2018, 13-16 June 2018, Poznań, Poland202104 bcwhVersion of RecordRGCOthersRGC: 25603916Others: NSFC 11504400, 61135003, 91420301, P0000424Publishe

The effects of acoustic variation on the perception of lexical tone in Cantonese-speaking congenital amusics

202105 bchyAccepted ManuscriptRGCOthersRGC: 25603916NSFC: 11504400, P0000424Publishe

DESEQUESTRATION DE POLLUANTS DE TYPE HYDROCARBURES AROMATIQUES POLYCYCLIQUES A L'INTERFACE EAU/SEDIMENTS A L'AIDE DE TENSIOACTIFS D'ORIGINE SYNTHETIQUE OU BIOLOGIQUE

International audienceDans le cadre du projet RESSOLV (REstauration des Sédiments et SOLs Vulnérables), projet émergeant du réseau de recherche Haut-Normand SCALE, les travaux présentés montrent les premiers résultats concernant le comportement de micropolluants organiques présents à l'interface eau/sédiments et leur déséquestration par des agents tensioactifs. Le but du projet est en fait d'atténuer la pollution des sédiments de dragage des ports, entre autre en Hydrocarbures Aromatiques Polycycliques (HAP), afin de diminuer leur teneur en dessous du niveau N 2 , voire N 1 de la réglementation GEODE 2000, et de pouvoir ainsi autoriser une immersion en mer ou une valorisation des sédiments dragués. Un procédé d'électromigration étant envisagé pour atténuer les teneurs en polluants cibles, il s'avère indispensable de solubiliser des espèces neutres et hydrophobes, telles les HAP, dans des systèmes chargés ayant la capacité de les transporter, grâce à un champ électrique, à travers le fluide interstitiel aqueux. Par conséquent, dans un premier temps, nous avons d'abord tenté de comprendre le comportement d'adsorption d'un mélange de 16 HAP à l'interface avec des surfaces modèles, telles le sable et le kaolin. Ces 16 HAP, présents à l'état de traces, ont été analysés après un enrichissement par SPE (Solid Phase Extraction), suivi d'une séparation et d'un dosage par chromatographie liquide alliée à une détection fluorimétrique. L'obtention d'isothermes d'adsorption, pour chaque HAP, a permis de comparer l'adsorption des HAP lourds par rapport aux HAP légers, ainsi que leur comportement sur les deux surfaces modèles. Dans un deuxième temps, un tensioactif anionique synthétique, le dodécyl sulfate de sodium (SDS) a été incorporé dans le milieu afin de désorber les HAP et de les re-solubiliser en phase aqueuse, afin de pouvoir mettre en oeuvre le procédé d'électromigration. Le SDS, utilisé à 10 fois sa concentration micellaire critique, a effectivement permis de re-solubiliser en partie les HAP, son effet étant moindre sur les HAP très lourds. Par la suite, des essais ont été effectués à partir d'un biosurfactant anionique original, de type cyclolipopeptide, produit par une souche bactérienne apparentée à Pseudomonas fluorescens, l'avantage du biosurfactant par rapport au SDS étant sa biodégradabilité et sa capacité à être produit in situ, en continu dans le réacteur

Acneic and non-acneic strains of Cutibacterium acnes: different behaviors depending on their microenvironment

International audienc