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276 results on '"Iatrou, Kostas"'

2. The Anopheles gambiae Odorant Binding Protein 1 (AgamOBP1) Mediates Indole Recognition in the Antennae of Female Mosquitoes

Author

Biessmann, Harald, Andronopoulou, Evi, Biessmann, Max R., Douris, Vassilis, Dimitratos, Spiros D., Eliopoulos, Elias, Guerin, Patrick M., Iatrou, Kostas, Justice, Robin W., Krober, Thomas, Marinotti, Osvaldo, Tsitoura, Panagiota, Woods, Daniel F., and Walter, Marika F.

Subjects
pheromone-sensitive neurons, culex-quinquefasciatus, oviposition attractants, sexual attraction, malaria mosquito, crystal-structure, silkworm moth, identification, receptor, expression
Abstract

Haematophagous insects are frequently carriers of parasitic diseases, including malaria. The mosquito Anopheles gambiae is the major vector of malaria in sub-Saharan Africa and is thus responsible for thousands of deaths daily. Although the role of olfaction in A. gambiae host detection has been demonstrated, little is known about the combinations of ligands and odorant binding proteins (OBPs) that can produce specific odor-related responses in vivo. We identified a ligand, indole, for an A. gambiae odorant binding protein, AgamOBP1, modeled the interaction in silico and confirmed the interaction using biochemical assays. RNAi-mediated gene silencing coupled with electrophysiological analyses confirmed that AgamOBP1 binds indole in A. gambiae and that the antennal receptor cells do not respond to indole in the absence of AgamOBP1. This case represents the first documented instance of a specific A. gambiae OBP–ligand pairing combination, demonstrates the significance of OBPs in odor recognition, and can be expanded to the identification of other ligands for OBPs of Anopheles and other medically important insects.

Published
2010

3. The impact of airline alliances on partners' traffic

Author

Iatrou, Kostas, Alamdari, Fariba, and Morrell, Peter

Subjects
387.71
Abstract

Airline alliances have been dominating the air transport industry since the 1990s and by now the four strategic alliances, in which almost all of the major airlines participate, control the 56% of the world RPK. The thesis examines the airline alliance phenomenon in its entirety and more specifically, it examines the reasons and circumstances that have led to the formulation of these alliances and the impact these alliances have had on the participating airlines. A key parameter airlines use to assess their own performance and that of alliances is traffic. Thus, the present research examines alliances impact on the traffic of the allied partners by different types of routes (hub-hub, hub-non hub and non hub-non hub), different types of cooperation (FFP, code share, strategic alliance without and with antitrust immunity) and by the length of the route. In addition, the thesis analyses which alliance groupings, which type of airline and which geographical area have produced the best results from the alliances. To achieve these objectives, the thesis is divided into a theoretical and an empirical part. The theoretical approach starts with an industry alliance overview and then moves to the presentation of airline alliances, by discussing the reasons that have led to their establishment, the evolution of the regulatory framework around which airline alliances have developed, the definition of airline alliances, the different forms they have taken, their advantages and disadvantages; and finally, the past and current alliance groups. The empirical part focuses on the alliance traffic and analyses it around two different axes. The first consists of a survey in which the airlines participating in alliances were asked to assess their alliance participation and to quantify the impact of alliances on several parameters of their operation and performance and more specifically, on their passenger traffic. The second analyzes this impact on the basis of an econometric model that seeks to determine and measure any positive impact on traffic volume generated by alliances. The findings indicate that airlines are satisfied from their alliance experience as they have helped them achieve the main purpose for which they have resorted to alliances, that is to secure increased network coverage with little capital investment. Both the survey and the econometric model indicate that airline alliances have led to an increase in passenger traffic amounting to 10%. According to the survey, this traffic increase is mainly registered on hubhub routes while the econometric model indicates that this increase is evenly distributed on hub-hub and hub-non hub routes. The benefits result mostly from the marketing cooperation and appear within one or two years from the establishment of the alliance. Alliances may bring about cost reduction, but this depends on the level of integration among the partners. Almost all participants agree that alliances are the final stage of airline cooperation and that there will be no or very few mergers.

Published
2004

7. Novel Anosmia‐Inducing Compounds for Environmentally Friendly Mosquito Vector Control: Structural Determinants of ORco Ligands Antagonizing Odorant Receptor Function

Author

Iatrou, Kostas, primary, Kythreoti, Georgia, additional, Thireou, Trias, additional, Karoussiotis, Christos, additional, Georgoussi, Zafiroula, additional, Zographos, Spyros E., additional, Liggri, Panagiota, additional, Michaelakis, Antonios, additional, and Schulz, Stefan, additional

Published
2022
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19. Introduction

Author

Gilbert, Lawrence I., primary, Iatrou, Kostas, additional, and Gill, Sarjeet, additional

Published
2005
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23. How Do Airlines Perceive That Strategic Alliances Affect Their Individual Branding?

Author

Kalligiannis, Konstantinos, Iatrou, Kostas, and Mason, Keith

Subjects
Air Transportation And Safety
Abstract

Much research has been carried out to evaluate the impact of strategic alliance membership on the performance of airlines. However it would be of interest to identify how airlines perceive this impact in terms of branding by each of the three global alliance groupings. It is the purpose of this paper to gather the opinion of airlines, belonging to the three strategic alliance groups, on the impact that the strategic alliance brands have had on their individual brands and how do they perceive that this impact will change in the future. To achieve this, a comprehensive survey of the alliance management and marketing departments of airlines participating in the three global strategic alliances was required. The results from this survey give an indication whether the strategic airline alliances, which are often referred to as marketing agreements, enhance, damage or have no impact on the individual airline brands.

Published
2006

24. An Attempt to Measure the Traffic Impact of Airline Alliances

Author

Iatrou, Kostas and Skourias, Nikolaos

Subjects
Air Transportation And Safety
Abstract

This paper analyzes the effects of airline alliances on the allied partners output by comparing the traffic change observed between the pre- and the post-alliance period. First, a simple methodology based on traffic passenger modelling is developed, and then an empirical analysis is conducted using time series from four global strategic alliances (Wings, Star Alliance, oneworld and SkyTeam) and 124 alliance routes. The analysis concludes that, all other things being equal, strategic alliances do lead to a 9.4%, on average, improvement in passenger volume.

Published
2005

25. The Empirical Analysis of Impact of Alliances on Airline Operations

Author

Iatrou, Kostas and Alamdari, Fariba

Subjects
Air Transportation And Safety
Abstract

Airline alliances are dominating the current air transport industry with the largest carriers of the world belonging to one of the four alliance groupings - "Wings", Star Alliance, one world, SkyTeam - which represent 56% of world Revenue Passenger Kilometers. Although much research has been carried out to evaluate the impact of alliance membership on performance of airlines, it would be of interest to ascertain the degree of impact perceived by participating airlines in alliances. It is the purpose of this paper to gather the opinion of all the airlines, belonging to the four global alliance groupings on the impact alliances have had on their traffic and on their performance in general To achieve this, a comprehensive survey of the alliance management departments of airlines participating in the four global strategic alliances was carried out. With this framework the survey has examined which type of cooperation among carriers (FFP, Code Share, Strategic Alliance without antitrust immunity, Strategic Alliance with antitrust immunity) has produced the most positive impact on traffic and which type of route (short haul, long haul, hub-hub, hub-non hub, non hub-non hub) has been mostly affected. In addition, the respondent airlines quantified the effect alliances have had on specific areas of their operation, such as load factors, traffic, costs, revenue and fares. Their responses have been analysed under each global alliances grouping, under airline and under geographic region to establish which group, type of carrier and geographic region has benefited most. The results show that each of the four global alliances groupings has experienced different results according to the type of collaboration agreed amongst their member airlines.

Published
2003

29. Identification of novel bioinspired synthetic mosquito repellents by combined ligand-based screening and OBP-structure-based molecular docking

Author

Thireou, Trias, primary, Kythreoti, Georgia, additional, Tsitsanou, Katerina E., additional, Koussis, Konstantinos, additional, Drakou, Christina E., additional, Kinnersley, Julie, additional, Kröber, Thomas, additional, Guerin, Patrick M., additional, Zhou, Jing-Jiang, additional, Iatrou, Kostas, additional, Eliopoulos, Elias, additional, and Zographos, Spyros E., additional

Published
2018
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30. Odorant-binding protein-based identification of natural spatial repellents for the African malaria mosquito Anopheles gambiae

Author

Kröber, Thomas, primary, Koussis, Konstantinos, additional, Bourquin, Martine, additional, Tsitoura, Panagiota, additional, Konstantopoulou, Maria, additional, Awolola, Taiwo Sam, additional, Dani, Francesca R., additional, Qiao, Huili, additional, Pelosi, Paolo, additional, Iatrou, Kostas, additional, and Guerin, Patrick M., additional

Published
2018
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35. Antennal expression pattern of two olfactory receptors and an odorant binding protein implicated in host odor detection by the malaria vector Anopheles gambiae

Author

Schymura, Danuta, Forstner, Maike, Schultze, Anna, Kröber, Thomas, Swevers, Luc, Iatrou, Kostas, Krieger, Jürgen, Schymura, Danuta, Forstner, Maike, Schultze, Anna, Kröber, Thomas, Swevers, Luc, Iatrou, Kostas, and Krieger, Jürgen

Abstract

Odor-detection in the malaria mosquito Anopheles gambiae involves large families of diverse proteins, including multiple odorant binding proteins (AgOBPs) and olfactory receptors (AgORs). The receptors AgOR1 and AgOR2, as well as the binding protein AgOBP1, have been implicated in the recognition of human host odors. In this study, we have explored the expression of these olfactory proteins, as well as the ubiquitous odorant receptor heteromerization partner AgOR7, in the thirteen flagellomeres (segments) of female and male antenna. Expressing cells were visualized by adapting a whole mount fluorescence in situ hybridization method. In female mosquitoes, AgOR1-expressing olfactory receptor neurons (ORNs) were almost exclusively segregated in segments 3 to 9, whereas AgOR2-expressing ORNs were distributed over flagellomeres 2 to 13. Different individuals comprised a similar number of cells expressing a distinct AgOR type, although their antennal topography and number per flagellomere varied. AgOBP1-expressing support cells were present in segments 3 to 13 of the female antenna, with increasing numbers towards the distal end. In male mosquitoes, total numbers of AgOR- and AgOBP1-expressing cells were much lower. While AgOR2-expressing cells were found on both terminal flagellomeres, AgOR1 cells were restricted to the most distal segment. High densities of AgOBP1-expressing cells were identified in segment 13, whereas segment 12 comprised very few. Altogether, the results demonstrate that both sexes express the two olfactory receptor types as well as the binding protein AgOBP1 but there is a significant sexual dimorphism concerning the number and distribution of these cells. This may suggest gender-specific differences in the ability to detect distinct odorants, specifically human host-derived volatiles.

Published
2016

40. Chorion Genes: A Landscape of Their Evolution, Structure, and Regulation

Author

Papantonis, Argyris, Swevers, Luc, Iatrou, Kostas, Papantonis, Argyris, Swevers, Luc, and Iatrou, Kostas

Abstract

Differential regulation at the level of transcription provides a means for controlling gene expression in eukaryotes, especially during development. Insect model systems have been extensively used to decipher the molecular basis of such regulatory cascades, and one of the oldest such model systems is the regulation of chorion gene expression during ovarian follicle maturation. Recent experimental and technological advances have shed new light onto the system, allowing us to revisit it. Thus, in this review we try to summarize almost 40 years' worth of studies on chorion gene regulation while-by comparing Bombyx mori and Drosophila melanogaster models-attempting to present a comprehensive, unified model of the various regulatory aspects of choriogenesis that takes into account the evolutionary conservation and divergence of the underlying mechanisms.

Published
2015

41. Crystal and Solution Studies of the 'Plus-C' Odorant-binding Protein 48 from Anopheles gambiae: CONTROL OF BINDING SPECIFICITY THROUGH THREE-DIMENSIONAL DOMAIN SWAPPING*

Author

Tsitsanou, Katerina E., Drakou, Christina E., Thireou, Trias, Vitlin Gruber, Anna, Kythreoti, Georgia, Azem, Abdussalam, Fessas, Dimitrios, Eliopoulos, Elias, Iatrou, Kostas, and Zographos, Spyros E.

Subjects
Arthropod Antennae, endocrine system, urogenital system, Crystallography, X-Ray, Lipocalins, Protein Structure, Tertiary, Structure-Activity Relationship, parasitic diseases, Protein Structure and Folding, Anopheles, Animals, Insect Proteins, Female, Protein Multimerization, Protein Structure, Quaternary, hormones, hormone substitutes, and hormone antagonists
Abstract

Much physiological and behavioral evidence has been provided suggesting that insect odorant-binding proteins (OBPs) are indispensable for odorant recognition and thus are appealing targets for structure-based discovery and design of novel host-seeking disruptors. Despite the fact that more than 60 putative OBP-encoding genes have been identified in the malaria vector Anopheles gambiae, the crystal structures of only six of them are known. It is therefore clear that OBP structure determination constitutes the bottleneck for structure-based approaches to mosquito repellent/attractant discovery. Here, we describe the three-dimensional structure of an A. gambiae "Plus-C" group OBP (AgamOBP48), which exhibits the second highest expression levels in female antennae. This structure represents the first example of a three-dimensional domain-swapped dimer in dipteran species. A combined binding site is formed at the dimer interface by equal contribution of each monomer. Structural comparisons with the monomeric AgamOBP47 revealed that the major structural difference between the two Plus-C proteins localizes in their N- and C-terminal regions, and their concerted conformational change may account for monomer-swapped dimer conversion and furthermore the formation of novel binding pockets. Using a combination of gel filtration chromatography, differential scanning calorimetry, and analytical ultracentrifugation, we demonstrate the AgamOBP48 dimerization in solution. Eventually, molecular modeling calculations were used to predict the binding mode of the most potent synthetic ligand of AgamOBP48 known so far, discovered by ligand- and structure-based virtual screening. The structure-aided identification of multiple OBP binders represents a powerful tool to be employed in the effort to control transmission of the vector-borne diseases.

Published
2013

42. Construction, complete sequence, and annotation of a BAC contig covering the silkworm chorion locus

Author

Chen, Zhiwei, primary, Nohata, Junko, additional, Guo, Huizhen, additional, Li, Shenglong, additional, Liu, Jianqiu, additional, Guo, Youbing, additional, Yamamoto, Kimiko, additional, Kadono-Okuda, Keiko, additional, Liu, Chun, additional, Arunkumar, Kallare P., additional, Nagaraju, Javaregowda, additional, Zhang, Yan, additional, Liu, Shiping, additional, Labropoulou, Vassiliki, additional, Swevers, Luc, additional, Tsitoura, Panagiota, additional, Iatrou, Kostas, additional, Gopinathan, Karumathil P., additional, Goldsmith, Marian R., additional, Xia, Qingyou, additional, and Mita, Kazuei, additional

Published
2015
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43. A comprehensive analysis of the chorion locus in silkmoth

Author

Chen, Zhiwei, primary, Nohata, Junko, additional, Guo, Huizhen, additional, Li, Shenglong, additional, Liu, Jianqiu, additional, Guo, Youbing, additional, Yamamoto, Kimiko, additional, Kadono-Okuda, Keiko, additional, Liu, Chun, additional, Arunkumar, Kallare P., additional, Nagaraju, Javaregowda, additional, Zhang, Yan, additional, Liu, Shiping, additional, Labropoulou, Vassiliki, additional, Swevers, Luc, additional, Tsitoura, Panagiota, additional, Iatrou, Kostas, additional, Gopinathan, Karumathil P., additional, Goldsmith, Marian R., additional, Xia, Qingyou, additional, and Mita, Kazuei, additional

Published
2015
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45. Applications of RNA Interference in Ecdysone Research

Author

Hannan, Garry N., primary, Hill, Ronald J., additional, Dedos, Skarlatos G., additional, Swevers, Luc, additional, Iatrou, Kostas, additional, Tan, Anjiang, additional, Parthasarathy, Ramaseshadri, additional, Bai, Hua, additional, Zhang, Zhaolin, additional, and Palli, Subba R., additional

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48. Expression of a Highly Antigenic and Native-Like Folded Extracellular Domain of the Human α1 Subunit of Muscle Nicotinic Acetylcholine Receptor, Suitable for Use in Antigen Specific Therapies for Myasthenia Gravis

Author

Niarchos, Athanasios, primary, Zouridakis, Marios, additional, Douris, Vassilis, additional, Georgostathi, Assimina, additional, Kalamida, Dimitra, additional, Sotiriadis, Alexandros, additional, Poulas, Konstantinos, additional, Iatrou, Kostas, additional, and Tzartos, Socrates J., additional

Published
2013
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49. RNA interference in Lepidoptera : An overview of successful and unsuccessful studies and implications for experimental design

Author

Terenius, Olle, Papanicolaou, Alexie, Garbutt, Jennie S., Eleftherianos, Ioannis, Huvenne, Hanneke, Kanginakudru, Sriramana, Albrechtsen, Merete, An, Chunju, Aymeric, Jean-Luc, Barthel, Andrea, Bebas, Piotr, Bitra, Kavita, Bravo, Alejandra, Chevalier, François, Collinge, Derek P., Crava, Cristina M., de Maagd, Ruud A., Duvic, Bernard, Erlandson, Martin, Faye, Ingrid, Felföldi, Gabriella, Fujiwara, Haruhiko, Futahashi, Ryo, Gandhe, Archana S., Gatehouse, Heather S., Gatehouse, Laurence N., Giebultowicz, Jadwiga M., Gómez, Isabel, Grimmelikhuijzen, Cornelis J. P., Groot, Astrid T., Hauser, Frank, Heckel, David G., Hegedus, Dwayne D., Hrycaj, Steven, Huang, Lihua, Hull, J. Joe, Iatrou, Kostas, Iga, Masatoshi, Kanost, Michael R., Kotwica, Joanna, Li, Changyou, Li, Jianghong, Liu, Jisheng, Lundmark, Magnus, Matsumoto, Shogo, Meyering-Vos, Martina, Millichap, Peter J., Monteiro, Antónia, Mrinal, Nirotpal, Niimi, Teruyuki, Nowara, Daniela, Ohnishi, Atsushi, Oostra, Vicencio, Ozaki, Katsuhisa, Papakonstantinou, Maria, Popadic, Aleksandar, Rajam, Manchikatla V., Saenko, Suzanne, Simpson, Robert M., Soberón, Mario, Strand, Michael R., Tomita, Shuichiro, Toprak, Umut, Wang, Ping, Wee, Choon Wei, Whyard, Steven, Zhang, Wenqing, Nagaraju, Javaregowda, Ffrench-Constant, Richard H., Herrero, Salvador, Gordon, Karl, Swevers, Luc, Smagghe, Guy, Terenius, Olle, Papanicolaou, Alexie, Garbutt, Jennie S., Eleftherianos, Ioannis, Huvenne, Hanneke, Kanginakudru, Sriramana, Albrechtsen, Merete, An, Chunju, Aymeric, Jean-Luc, Barthel, Andrea, Bebas, Piotr, Bitra, Kavita, Bravo, Alejandra, Chevalier, François, Collinge, Derek P., Crava, Cristina M., de Maagd, Ruud A., Duvic, Bernard, Erlandson, Martin, Faye, Ingrid, Felföldi, Gabriella, Fujiwara, Haruhiko, Futahashi, Ryo, Gandhe, Archana S., Gatehouse, Heather S., Gatehouse, Laurence N., Giebultowicz, Jadwiga M., Gómez, Isabel, Grimmelikhuijzen, Cornelis J. P., Groot, Astrid T., Hauser, Frank, Heckel, David G., Hegedus, Dwayne D., Hrycaj, Steven, Huang, Lihua, Hull, J. Joe, Iatrou, Kostas, Iga, Masatoshi, Kanost, Michael R., Kotwica, Joanna, Li, Changyou, Li, Jianghong, Liu, Jisheng, Lundmark, Magnus, Matsumoto, Shogo, Meyering-Vos, Martina, Millichap, Peter J., Monteiro, Antónia, Mrinal, Nirotpal, Niimi, Teruyuki, Nowara, Daniela, Ohnishi, Atsushi, Oostra, Vicencio, Ozaki, Katsuhisa, Papakonstantinou, Maria, Popadic, Aleksandar, Rajam, Manchikatla V., Saenko, Suzanne, Simpson, Robert M., Soberón, Mario, Strand, Michael R., Tomita, Shuichiro, Toprak, Umut, Wang, Ping, Wee, Choon Wei, Whyard, Steven, Zhang, Wenqing, Nagaraju, Javaregowda, Ffrench-Constant, Richard H., Herrero, Salvador, Gordon, Karl, Swevers, Luc, and Smagghe, Guy

Abstract

Gene silencing through RNA interference (RNAi) has revolutionized the study of gene function, particularly in non-model insects. However, in Lepidoptera (moths and butterflies) RNAi has many times proven to be difficult to achieve. Most of the negative results have been anecdotal and the positive experiments have not been collected in such a way that they are possible to analyze. In this review, we have collected detailed data from more than 150 experiments including all to date published and many unpublished experiments. Despite a large variation in the data, trends that are found are that RNAi is particularly successful in the family Saturniidae and in genes involved in immunity. On the contrary, gene expression in epidermal tissues seems to be most difficult to silence. In addition, gene silencing by feeding dsRNA requires high concentrations for success. Possible causes for the variability of success in RNAi experiments in Lepidoptera are discussed. The review also points to a need to further investigate the mechanism of RNAi in lepidopteran insects and its possible connection to the innate immune response. Our general understanding of RNAi in Lepidoptera will be further aided in the future as our public database at http://insectacentral.org/RNAi will continue to gather information on RNAi experiments.

Published
2011
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