Systematic revision of the ‘diminutive’ Kentish Plover (Charadriidae:<i> Charadrius</i>) with the resurrection of <i>Charadrius seebohmi </i>based on phenotypic and genetic analyses

The Kentish Plover Charadrius alexandrinus Linnaeus 1758 is a common shorebird in Eurasia and North Africa that breeds in a variety of habitats, exhibits different extents of migratory behaviour and is an emerging model species of breeding system evolution. Here we focus on the resident population found across the southern tip of India and Sri Lanka, and re-evaluate its systematic status based on phenotypic and genetic distinctiveness from a sympatric migrant, Charadrius alexandrinus sensu stricto, and the recently elevated closely related Charadrius dealbatus in East Asia. We show that the Sri Lankan and South Indian (South Asian) population differs in body size, moulting pattern and plumage coloration from C. alexandrinus and C. dealbatus. Furthermore, based on two mitochondrial, two sex-linked and 11 autosomal microsatellite markers from 378 individuals, we show that these three taxa have moderate genetic differentiation (Fst 0.078–0.096). The South Asian taxon is sister to the clade of C. alexandrinus sensu stricto and C. dealbatus with an estimated divergence time of 1.19 million years ago. We also examined ornithological records of major museum collections in Asia, Europe and North America for the south Asian taxon to evaluate its biogeographical and taxonomic status. Based on differences in genotype, phenotype, allochronic migratory pattern and breeding range, we resurrect the most suitable synonym, Charadrius alexandrinus seebohmi Hartert and Jackson, 1915, and elevate the nomen to the species level with the proposed English name ‘Hanuman Plover’.</p

An opto-electronic nose based on surface plasmon resonance imaging : the underlying mechanisms

L'imagerie par résonance plasmonique de surface est une technique largement utilisée dans le domaine de la détection biomoléculaire en phase liquide. En 2012, notre laboratoire a démontré son aptitude au développement d'un nez optoélectronique à l'aide d'un réseau de capteurs à base de peptides. Peu de temps après, un dispositif fonctionnel a été valorisé par la start-up Aryballe Technologies pour la détection sensible et sélective des composés organiques volatils (COV) en phase gazeuse. Depuis sa conception, une compréhension fondamentale de la sensibilité plasmonique et des mécanismes de reconnaissance, dans le cadre de la détection et de la discrimination en phase gazeuse, n'a pas été réalisée. Cette thèse tente de comprendre les mécanismes sous-jacents régissant la fonctionnalité de l'appareil. Tout d'abord, le mécanisme de contribution plasmonique en phase gazeuse a été étudié et élucidé à travers l'élaboration d'un modèle numérique complet basé sur le formalisme de la matrice de transfert. Une approche corrective a été proposée pour adapter ce modèle afin de mieux représenter la réalité expérimentale à la lumière d'un décalage associé à la topographie de surface. Deuxièmement, les contributions des récepteurs biomoléculaires ont été étudiées, de l'immobilisation des peptides à leurs mécanismes d'interaction avec les COV en phase gazeuse. De plus, un accent particulier a été mis sur l'étude des effets de la température et de l'humidité. Enfin, l'utilisation d'un peptide de type tensioactif spécialement conçu a été proposée pour la fabrication de nanoarchitectures de surfaces bio-hybrides, grâce à laquelle un réseau de capteurs fonctionnels a été développé avec des éléments de détection variant uniquement par leur morphologie de surface. En substance, l'interaction entre la structure et la fonction a été le thème principal de ce travail, ouvrant potentiellement la voie à des performances plus élevées pour ces appareils de nez optoélectroniques.Surface Plasmon Resonance Imaging is a technique widely used in the field of biomolecular sensing in the liquid phase. In 2012, our laboratory demonstrated its applicability as an optoelectronic nose using a peptide-based sensor array. Soon after, a functional device was valorized by the start-up Aryballe Technologies towards the sensitive and selective detection of Volatile Organic Compounds (VOCs) in the gas phase. Since its conception, a fundamental understanding regarding its plasmonic sensitivity and recognition mechanisms, in the context of gas-phase detection and discrimination, has not been performed. This Ph.D. thesis attempts to unravel these underlying mechanisms governing the functionality of the device. Firstly, the plasmonic contribution mechanism in the gas phase was investigated and elucidated through the elaboration of a comprehensive numerical model based on the Transfer Matrix Formalism. A corrective approach was proposed to adapt this model to better represent experimental realities in light of a surface topography associated mismatch. Secondly, the biomolecular receptor contributions were studied, from peptide immobilization to their interaction mechanisms with small VOCs in the gas phase. Moreover, a particular emphasis was devoted to studying the temperature and humidity effects. Finally, the use of a specially designed surfactant-like peptide was proposed towards the fabrication of bio-hybrid surface nanoarchitecture, through which a functional sensor array was developed with sensing elements solely varying in surface morphology. In essence, the interplay between structure and function has been the overarching theme of this work, potentially paving the way towards achieving higher performances for such optoelectronic nose devices

Electronic noses: Novel sensing materials for better performances

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Biomimetic olfactory biosensors and bioelectronic noses

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Optical Index Prism Sensitivity of Surface Plasmon Resonance Imaging in Gas Phase: Experiment versus Theory

International audienceRecent advances in SPR-imaging detection in gas phase have led to the development of opto-electronic noses (opto-eNs) requiring the need for optical sensitivity characterization of such devices. Understanding of the optical contributions will have an implicit relevance on sensitivity enhancement of SPR-imaging in gas phase valuable to improve the performance of opto-eN and potentially open new applications as gas sensors. In this paper, we analyzed the optical contributions to the sensitivity of the SPR imaging prisms and potential insights into their contributing factors. We established a characterization method for the SPR prism sensitivity that is independent of the carrier gas considered. Then, by using this sensitivity parameter, the influence of two different kinds of adhesive layers, Cr and Ti, of the gold coated prisms were studied. Furthermore, we considered a theoretical model to rationalize our experimental results, which demonstrated the relevance of surface topography on the optical index 1 sensitivity. Those surface topographies were characterized experimentally and were implemented in the model free from any additional fitting parameters using a modified Maxwell-Garnet theory. Finally, the model was shown to predictively assess the experimentally measured effects of temperature on the prism sensitivity

Biomimetic optoelectronic nose for analysis of volatile organic compounds

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An Overview of Artificial Olfaction Systems with a Focus on Surface Plasmon Resonance for the Analysis of Volatile Organic Compounds

International audienceThe last three decades have witnessed an increasing demand for novel analytical tools for the analysis of gases including odorants and volatile organic compounds (VOCs) in various domains. Traditional techniques such as gas chromatography coupled with mass spectrometry, although very efficient, present several drawbacks. Such a context has incited the research and industrial communities to work on the development of alternative technologies such as artificial olfaction systems, including gas sensors, olfactory biosensors and electronic noses (eNs). A wide variety of these systems have been designed using chemiresistive, electrochemical, acoustic or optical transducers. Among optical transduction systems, surface plasmon resonance (SPR) has been extensively studied thanks to its attractive features (high sensitivity, label free, real-time measurements). In this paper, we present an overview of the advances in the development of artificial olfaction systems with a focus on their development based on propagating SPR with different coupling configurations, including prism coupler, wave guide, and grating

Development of an optoelectronic nose based on surface plasmon resonance imaging with peptide and hairpin DNA for sensing volatile organic compounds

International audienceNowadays, the analysis of volatile organic compounds (VOCs) is very important in various domains. For this, in the last decades, electronic noses have emerged as promising alternatives to traditional analytical methods. Nevertheless, their wide use is still limited by their performances such as low selectivity. Herein, we developed an optoelectronic nose using virtually screened peptides and hairpin DNA (hpDNA) with improved selectivity as sensing materials and surface plasmon resonance imaging (SPRi) as the detection system. Thanks to the complementarity of their binding properties towards target VOCs, the obtained optoelectronic nose has very good selectivity, being able to discriminate not only between VOCs of different chemical families, but also VOCs of the same family with only 1-carbon difference. We thus confirmed that computational virtual screening, which allows 'in silico' testing of VOC-peptide binding in a fast and low-cost way, is very promising for the selection of sensing elements with higher sensitivity and selectivity as well as great diversity. The combination of these sensing materials with SPRi is relevant for the development of optoelectronic nose with large sensor arrays and improved performances

Surface plasmon resonance imaging based on peptide and HpDNA for sensing volatile organic compounds

International audienc

Opto-electronic nose - temperature and VOC concentration effects on the equilibrium response

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