129 results on '"Christos Louis"'
Search Results
2. Essential role of Plasmodium perforin-like protein 4 in ookinete midgut passage.
- Author
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Elena Deligianni, Natalie C Silmon de Monerri, Paul J McMillan, Lucia Bertuccini, Fabiana Superti, Maria Manola, Lefteris Spanos, Christos Louis, Michael J Blackman, Leann Tilley, and Inga Siden-Kiamos
- Subjects
Medicine ,Science - Abstract
Pore forming proteins such as those belonging to the membrane attack/perforin (MACPF) family have important functions in many organisms. Of the five MACPF proteins found in Plasmodium parasites, three have functions in cell passage and one in host cell egress. Here we report an analysis of the perforin-like protein 4, PPLP4, in the rodent parasite Plasmodium berghei. We found that the protein is expressed only in the ookinete, the invasive stage of the parasite formed in the mosquito midgut. Transcriptional analysis revealed that expression of the pplp4 gene commences during ookinete development. The protein was detected in retorts and mature ookinetes. Using two antibodies, the protein was found localized in a dotted pattern, and 3-D SIM super-resolution microcopy revealed the protein in the periphery of the cell. Analysis of a C-terminal mCherry fusion of the protein however showed mainly cytoplasmic label. A pplp4 null mutant formed motile ookinetes, but these were unable to invade and traverse the midgut epithelium resulting in severely impaired oocyst formation and no transmission to naïve mice. However, when in vitro cultured ookinetes were injected into the thorax of the mosquito, thus by-passing midgut passage, sporozoites were formed and the mutant parasites were able to infect naïve mice. Taken together, our data show that PPLP4 is required only for ookinete invasion of the mosquito midgut. Thus PPLP4 has a similar role to the previously studied PPLP3 and PPLP5, raising the question why three proteins with MACPF domains are needed for invasion by the ookinete of the mosquito midgut epithelium.
- Published
- 2018
- Full Text
- View/download PDF
3. Daily Newspaper View of Dengue Fever Epidemic, Athens, Greece, 1927–1931
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Christos Louis
- Subjects
Aedes aegypti ,dengue virus ,dengue hemorrhagic fever ,viruses ,epidemic ,vector-borne infections ,Medicine ,Infectious and parasitic diseases ,RC109-216 - Abstract
During the late summers of 1927 and 1928, a biphasic dengue epidemic affected the Athens, Greece, metropolitan area; >90% of the population became sick, and >1,000 persons (1,553 in the entire country) died. This epidemic was the most recent and most serious dengue fever epidemic in Europe. Review of all articles published by one of the most influential Greek daily newspapers (I Kathimerini) during the epidemic and the years that followed it did not shed light on the controversy about whether the high number of deaths resulted from dengue hemorrhagic fever after sequential infections with dengue virus types 1 and 2 or to a particularly virulent type 1 virus. Nevertheless, study of the old reports is crucial considering the relatively recent introduction of Aedes albopictus mosquitoes and the frequent warnings of a possible reemergence of dengue fever in Europe.
- Published
- 2012
- Full Text
- View/download PDF
4. Describing the breakbone fever: IDODEN, an ontology for dengue fever.
- Author
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Elvira Mitraka, Pantelis Topalis, Vicky Dritsou, Emmanuel Dialynas, and Christos Louis
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Arctic medicine. Tropical medicine ,RC955-962 ,Public aspects of medicine ,RA1-1270 - Abstract
BACKGROUND:Ontologies represent powerful tools in information technology because they enhance interoperability and facilitate, among other things, the construction of optimized search engines. To address the need to expand the toolbox available for the control and prevention of vector-borne diseases we embarked on the construction of specific ontologies. We present here IDODEN, an ontology that describes dengue fever, one of the globally most important diseases that are transmitted by mosquitoes. METHODOLOGY/PRINCIPAL FINDINGS:We constructed IDODEN using open source software, and modeled it on IDOMAL, the malaria ontology developed previously. IDODEN covers all aspects of dengue fever, such as disease biology, epidemiology and clinical features. Moreover, it covers all facets of dengue entomology. IDODEN, which is freely available, can now be used for the annotation of dengue-related data and, in addition to its use for modeling, it can be utilized for the construction of other dedicated IT tools such as decision support systems. CONCLUSIONS/SIGNIFICANCE:The availability of the dengue ontology will enable databases hosting dengue-associated data and decision-support systems for that disease to perform most efficiently and to link their own data to those stored in other independent repositories, in an architecture- and software-independent manner.
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- 2015
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5. Anopheles immune genes and amino acid sites evolving under the effect of positive selection.
- Author
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Aristeidis Parmakelis, Marina Moustaka, Nikolaos Poulakakis, Christos Louis, Michel A Slotman, Jonathon C Marshall, Parfait H Awono-Ambene, Christophe Antonio-Nkondjio, Frederic Simard, Adalgisa Caccone, and Jeffrey R Powell
- Subjects
Medicine ,Science - Abstract
It has long been the goal of vector biology to generate genetic knowledge that can be used to "manipulate" natural populations of vectors to eliminate or lessen disease burden. While long in coming, progress towards reaching this goal has been made. Aiming to increase our understanding regarding the interactions between Plasmodium and the Anopheles immune genes, we investigated the patterns of genetic diversity of four anti-Plasmodium genes in the Anopheles gambiae complex of species.Within a comparative phylogenetic and population genetics framework, the evolutionary history of four innate immunity genes within the An. gambiae complex (including the two most important human malaria vectors, An. gambiae and An. arabiensis) is reconstructed. The effect of natural selection in shaping the genes' diversity is examined. Introgression and retention of ancestral polymorphisms are relatively rare at all loci. Despite the potential confounding effects of these processes, we could identify sites that exhibited dN/dS ratios greater than 1.In two of the studied genes, CLIPB14 and FBN8, several sites indicated evolution under positive selection, with CLIPB14 exhibiting the most consistent evidence. Considering only the sites that were consistently identified by all methods, two sites in CLIPB14 are adaptively driven. However, the analysis inferring the lineage -specific evolution of each gene was not in favor of any of the Anopheles lineages evolving under the constraints imposed by positive selection. Nevertheless, the loci and the specific amino acids that were identified as evolving under strong evolutionary pressure merit further investigation for their involvement in the Anopheles defense against microbes in general.
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- 2010
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6. MIRO and IRbase: IT tools for the epidemiological monitoring of insecticide resistance in mosquito disease vectors.
- Author
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Emmanuel Dialynas, Pantelis Topalis, John Vontas, and Christos Louis
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Arctic medicine. Tropical medicine ,RC955-962 ,Public aspects of medicine ,RA1-1270 - Abstract
Monitoring of insect vector populations with respect to their susceptibility to one or more insecticides is a crucial element of the strategies used for the control of arthropod-borne diseases. This management task can nowadays be achieved more efficiently when assisted by IT (Information Technology) tools, ranging from modern integrated databases to GIS (Geographic Information System). Here we describe an application ontology that we developed de novo, and a specially designed database that, based on this ontology, can be used for the purpose of controlling mosquitoes and, thus, the diseases that they transmit.The ontology, named MIRO for Mosquito Insecticide Resistance Ontology, developed using the OBO-Edit software, describes all pertinent aspects of insecticide resistance, including specific methodology and mode of action. MIRO, then, forms the basis for the design and development of a dedicated database, IRbase, constructed using open source software, which can be used to retrieve data on mosquito populations in a temporally and spatially separate way, as well as to map the output using a Google Earth interface. The dependency of the database on the MIRO allows for a rational and efficient hierarchical search possibility.The fact that the MIRO complies with the rules set forward by the OBO (Open Biomedical Ontologies) Foundry introduces cross-referencing with other biomedical ontologies and, thus, both MIRO and IRbase are suitable as parts of future comprehensive surveillance tools and decision support systems that will be used for the control of vector-borne diseases. MIRO is downloadable from and IRbase is accessible at VectorBase, the NIAID-sponsored open access database for arthropod vectors of disease.
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- 2009
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7. miRNAO: An Ontology Unfolding the Domain of microRNAs.
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Vicky Dritsou, Pantelis Topalis, Elvira Mitraka, Emmanuel Dialynas, and Christos Louis
- Published
- 2014
8. VectorBase: improvements to a bioinformatics resource for invertebrate vector genomics.
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Karine Megy, Scott J. Emrich, Daniel Lawson, David Campbell, Emmanuel Dialynas, Daniel S. T. Hughes, Gautier Koscielny, Christos Louis, Robert M. MacCallum, Seth Redmond, Andrew Sheehan, Pantelis Topalis, and Derek Wilson
- Published
- 2012
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9. A set of ontologies to drive tools for the control of vector-borne diseases.
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Pantelis Topalis, Emmanuel Dialynas, Elvira Mitraka, Elena Deligianni, Inga Siden-Kiamos, and Christos Louis
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- 2011
- Full Text
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10. VectorBase: a data resource for invertebrate vector genomics.
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Daniel Lawson, Peter Arensburger, Peter Atkinson, Nora J. Besansky, Robert V. Bruggner, Ryan Butler, Kathryn S. Campbell, George K. Christophides, Scott Christley, Emmanuel Dialynas, Martin Hammond, Catherine A. Hill, Nathan Konopinski, Neil F. Lobo, Robert M. MacCallum, Gregory R. Madey, Karine Megy, Jason Meyer, Seth Redmond, David W. Severson, Eric O. Stinson, Pantelis Topalis, Ewan Birney, William M. Gelbart, Fotis C. Kafatos, Christos Louis, and Frank H. Collins
- Published
- 2009
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11. Fotis C. Kafatos. 16 April 1940—18 November 2017
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Christos Louis and Marian R. Goldsmith
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010504 meteorology & atmospheric sciences ,010102 general mathematics ,General Medicine ,0101 mathematics ,Biology ,01 natural sciences ,0105 earth and related environmental sciences - Published
- 2020
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12. Getting the Best from Two Worlds: Converting Between OBO and OWL Formats.
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Vicky Dritsou, Elvira Mitraka, Pantelis Topalis, and Christos Louis
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- 2012
13. miRNAO: An Ontology for microRNAs.
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Vicky Dritsou, Pantelis Topalis, Emmanuel Dialynas, Elvira Mitraka, and Christos Louis
- Published
- 2012
14. IDODEN: An Ontology for Dengue.
- Author
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Elvira Mitraka, Pantelis Topalis, Emmanuel Dialynas, Vicky Dritsou, and Christos Louis
- Published
- 2012
15. VectorBase: a home for invertebrate vectors of human pathogens.
- Author
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Daniel Lawson, Peter Arensburger, Peter Atkinson, Nora J. Besansky, Robert V. Bruggner, Ryan Butler, Kathryn S. Campbell, George K. Christophides, Scott Christley, Emmanuel Dialynas, David B. Emmert, Martin Hammond, Catherine A. Hill, Ryan C. Kennedy, Neil F. Lobo, Robert M. MacCallum, Gregory R. Madey, Karine Megy, Seth Redmond, Susan Russo, David W. Severson, Eric O. Stinson, Pantelis Topalis, Evgeni M. Zdobnov, Ewan Birney, William M. Gelbart, Fotis C. Kafatos, Christos Louis, and Frank H. Collins
- Published
- 2007
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16. The internet era for pandemics
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Christos Louis
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Internet ,Economic growth ,Coronavirus disease 2019 (COVID-19) ,business.industry ,Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) ,Politics ,Public Health, Environmental and Occupational Health ,History, 19th Century ,General Medicine ,History, 20th Century ,Plague (disease) ,History, 21st Century ,Microbiology ,History, Medieval ,Infectious Diseases ,Geography ,Pandemic ,Commentary ,Humans ,Parasitology ,The Internet ,business ,Pandemics ,History, Ancient - Abstract
The first epidemic for which historical reports exist is the ‘Plague of Athens,’ which burst into the city in 430 BC. The still unidentified pathogen responsible for this killer epidemic may have b...
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- 2021
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17. IDOMAL: the malaria ontology revisited.
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Pantelis Topalis, Elvira Mitraka, Vicky Dritsou, Emmanuel Dialynas, and Christos Louis
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- 2013
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18. The Ontology for Parasite Lifecycle (OPL): towards a consistent vocabulary of lifecycle stages in parasitic organisms.
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Priti Parikh, Jie Zheng 0001, Flora J. Logan-Klumpler, Christian J. Stoeckert Jr., Christos Louis, Pantelis Topalis, Anna V. Protasio, Amit P. Sheth, Mark Carrington, Matthew Berriman, and Satya Sanket Sahoo
- Published
- 2012
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19. Ontologies and Vector-Borne Diseases: New Tools for Old Illnesses.
- Author
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Pantelis Topalis, Emmanuel Dialynas, and Christos Louis
- Published
- 2010
20. Essential role of Plasmodium perforin-like protein 4 in ookinete midgut passage
- Author
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Inga Siden-Kiamos, Natalie C. Silmon de Monerri, Lefteris Spanos, Elena Deligianni, Maria S. Manola, Christos Louis, Michael J. Blackman, Fabiana Superti, Lucia Bertuccini, Leann Tilley, and Paul J. McMillan
- Subjects
0301 basic medicine ,Male ,Plasmodium ,Cytoplasm ,Physiology ,Plasmodium berghei ,Mutant ,Cell Membranes ,Protozoan Proteins ,lcsh:Medicine ,Epithelium ,Mice ,Medicine and Health Sciences ,lcsh:Science ,Regulation of gene expression ,MACPF ,Multidisciplinary ,biology ,Gene Expression Regulation, Developmental ,3. Good health ,Cell biology ,Body Fluids ,Blood ,Sporozoites ,Female ,Cellular Structures and Organelles ,Anatomy ,Research Article ,03 medical and health sciences ,Parasite Groups ,parasitic diseases ,Parasitic Diseases ,Animals ,Perforin ,lcsh:R ,fungi ,Oocysts ,Biology and Life Sciences ,Midgut ,Cell Biology ,Blood Serum ,biology.organism_classification ,Malaria ,030104 developmental biology ,Biological Tissue ,Culicidae ,Mutation ,biology.protein ,lcsh:Q ,Parasitology ,Apicomplexa ,Immune Serum ,Digestive System - Abstract
Pore forming proteins such as those belonging to the membrane attack/perforin (MACPF) family have important functions in many organisms. Of the five MACPF proteins found in Plasmodium parasites, three have functions in cell passage and one in host cell egress. Here we report an analysis of the perforin-like protein 4, PPLP4, in the rodent parasite Plasmodium berghei. We found that the protein is expressed only in the ookinete, the invasive stage of the parasite formed in the mosquito midgut. Transcriptional analysis revealed that expression of the pplp4 gene commences during ookinete development. The protein was detected in retorts and mature ookinetes. Using two antibodies, the protein was found localized in a dotted pattern, and 3-D SIM super-resolution microcopy revealed the protein in the periphery of the cell. Analysis of a C-terminal mCherry fusion of the protein however showed mainly cytoplasmic label. A pplp4 null mutant formed motile ookinetes, but these were unable to invade and traverse the midgut epithelium resulting in severely impaired oocyst formation and no transmission to naïve mice. However, when in vitro cultured ookinetes were injected into the thorax of the mosquito, thus by-passing midgut passage, sporozoites were formed and the mutant parasites were able to infect naïve mice. Taken together, our data show that PPLP4 is required only for ookinete invasion of the mosquito midgut. Thus PPLP4 has a similar role to the previously studied PPLP3 and PPLP5, raising the question why three proteins with MACPF domains are needed for invasion by the ookinete of the mosquito midgut epithelium.
- Published
- 2018
21. Asaiaaccelerates larval development ofAnopheles gambiae
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George K. Christophides, Inga Siden-Kiamos, Christos Louis, Elvira Mitraka, and Stavros Stathopoulos
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Anopheles gambiae ,Zoology ,Paratransgenesis ,Biology ,Southeast asian ,Microbiology ,03 medical and health sciences ,Anopheles ,parasitic diseases ,Animals ,Symbiosis ,Anopheles stephensi ,030304 developmental biology ,0303 health sciences ,Larva ,030306 microbiology ,Ecology ,Transmission (medicine) ,Gene Expression Profiling ,fungi ,Public Health, Environmental and Occupational Health ,Midgut ,General Medicine ,Microarray Analysis ,biology.organism_classification ,3. Good health ,Human morbidity ,Gastrointestinal Tract ,Infectious Diseases ,Acetobacteraceae ,Original Article ,Parasitology - Abstract
Arthropod borne diseases cause significant human morbidity and mortality and, therefore, efficient measures to control transmission of the disease agents would have great impact on human health. One strategy to achieve this goal is based on the manipulation of bacterial symbionts of vectors. Bacteria of the Gram-negative, acetic acid bacterium genus Asaia have been found to be stably associated with larvae and adults of the Southeast Asian malaria vector Anopheles stephensi, dominating the microbiota of the mosquito. We show here that after the infection of Anopheles gambiae larvae with Asaia the bacteria were stably associated with the mosquitoes, becoming part of the microflora of the midgut and remaining there for the duration of the life cycle. Moreover they were passed on to the next generation through vertical transmission. Additionally, we show that there is an increase in the developmental rate when additional bacteria are introduced into the organism which leads us to the conclusion that Asaia plays a yet undetermined crucial role during the larval stages. Our microarray analysis showed that the larval genes that are mostly affected are involved in cuticle formation, and include mainly members of the CPR gene family.
- Published
- 2013
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22. A perforin-like protein mediates disruption of the erythrocyte membrane during egress ofPlasmodium bergheimale gametocytes
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Gabriele Pradel, Natalie C. Silmon de Monerri, Inga Siden-Kiamos, Christine C. Wirth, Elena Deligianni, Lefteris Spanos, Christos Louis, Rhiannon N. Morgan, Michael J. Blackman, and Lucia Bertuccini
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Immunology ,Mutant ,Motility ,Flagellum ,Biology ,biology.organism_classification ,Microbiology ,Plasmodium ,Cell biology ,Perforin ,Virology ,Gametocyte ,biology.protein ,Plasmodium berghei ,Gametogenesis - Abstract
Successful gametogenesis of the malaria parasite depends on egress of the gametocytes from the erythrocytes within which they developed. Egress entails rupture of both the parasitophorous vacuole membrane and the erythrocyte plasma membrane, and precedes the formation of the motile flagellated male gametes in a process called exflagellation. We show here that egress of the male gametocyte depends on the function of a perforin-like protein, PPLP2. A mutant of Plasmodium berghei lacking PPLP2 displayed abnormal exflagellation; instead of each male gametocyte forming eight flagellated gametes, it produced gametocytes with only one, shared thicker flagellum. Using immunofluorescence and transmission electron microscopy analysis, and phenotype rescue with saponin or a pore-forming toxin, we conclude that rupture of the erythrocyte membrane is blocked in the mutant. The parasitophorous vacuole membrane, on the other hand, is ruptured normally. Some mutant parasites are still able to develop in the mosquito, possibly because the vigorous motility of the flagellated gametes eventually leads to escape from the persisting erythrocyte membrane. This is the first example of a perforin-like protein in Plasmodium parasites having a role in egress from the host cell and the first parasite protein shown to be specifically required for erythrocyte membrane disruption during egress.
- Published
- 2013
- Full Text
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23. Médecins Sans Frontières and the refugee crisis in Greece: An interview with Dr. Apostolos Veizis
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Christos Louis
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Refugees ,Greece ,030503 health policy & services ,Refugee ,Refugee crisis ,World War II ,Public Health, Environmental and Occupational Health ,Medical Missions ,Relief Work ,General Medicine ,Microbiology ,03 medical and health sciences ,0302 clinical medicine ,Infectious Diseases ,Environmental protection ,Political science ,Economic history ,Humans ,Parasitology ,030212 general & internal medicine ,Interview ,Voluntary Health Agencies ,0305 other medical science - Abstract
Europe is presently witnessing the biggest movement of human populations since the end of the World War II. The armed conflicts in Afghanistan, Syria, Yemen, to mention just a few of the ongoing wa...
- Published
- 2016
24. Distinct roles for pbs21 and pbs25 in the in vitro ookinete to oocyst transformation of Plasmodium berghei
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Andrew P. Waters, Dina Vlachou, Gabrielle Margos, Annette L. Beetsma, Robert E. Sinden, Inga Siden-Kiamos, and Christos Louis
- Subjects
Plasmodium berghei ,Recombinant Fusion Proteins ,Mutant ,Protozoan Proteins ,Motility ,Cell Line ,Mice ,Aedes ,Two-Hybrid System Techniques ,Anopheles ,parasitic diseases ,Animals ,Microscopy, Phase-Contrast ,biology ,fungi ,Midgut ,Cell Biology ,biology.organism_classification ,Coculture Techniques ,In vitro ,Yeast ,Rats ,Cell biology ,Drosophila melanogaster ,Microscopy, Fluorescence ,Cell culture ,Culture Media, Conditioned ,Mutation ,Locomotion - Abstract
We have developed an in vitro culture system for early sporogonic stages of Plasmodium berghei, which can be used to study developmental events normally taking place in the midgut of an infected mosquito. These include penetration of insect cells by the mature ookinete, transformation into oocysts and the early development of the latter, sustained through several rounds of nuclear division. The system, based upon co-culture of enriched ookinetes with several established insect cell lines, was used to study the development of mutant ookinetes lacking both the Pbs21 and Pbs25 surface proteins. Motility and entry of double knockout and Pbs21 single knockout ookinetes into the insect cells are normal, but the number of ookinetes successfully transforming into oocysts expressing the CSP protein are substantially reduced. Finally, using the yeast two-hybrid system we also show that Pbs25 has the capacity to homodimerise as well as to form heterodimers with Pbs21.
- Published
- 2016
25. Plasmodium berghei calcium-dependent protein kinase 3 is required for ookinete gliding motility and mosquito midgut invasion
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Oliver Billker, Christos Louis, Inga Siden-Kiamos, Andrea Ecker, Saga Nybäck, and Robert E. Sinden
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Gliding motility ,Plasmodium berghei ,Mutant ,Protozoan Proteins ,Motility ,Microbiology ,Epithelium ,Apicomplexa ,03 medical and health sciences ,Mice ,Cell Movement ,parasitic diseases ,Anopheles ,Animals ,Molecular Biology ,030304 developmental biology ,0303 health sciences ,biology ,030306 microbiology ,Midgut ,biology.organism_classification ,Transmembrane protein ,3. Good health ,Cell biology ,Insect Vectors ,Intestines ,Second messenger system ,Protein Kinases ,Gene Deletion - Abstract
Apicomplexan parasites critically depend on a unique form of gliding motility to colonize their hosts and to invade cells. Gliding requires different stage and species-specific transmembrane adhesins, which interact with an intracellular motor complex shared across parasite stages and species. How gliding is regulated by extracellular factors and intracellular signalling mechanisms is largely unknown, but current evidence suggests an important role for cytosolic calcium as a second messenger. Studying a Plasmodium berghei gene deletion mutant, we here provide evidence that a calcium-dependent protein kinase, CDPK3, has an important function in regulating motility of the ookinete in the mosquito midgut. We show that a cdpk3- parasite clone produces morphologically normal ookinetes, which fail to engage the midgut epithelium, due to a marked reduction in their ability to glide productively, resulting in marked reduction in malaria transmission to the mosquito. The mutant was successfully complemented with an episomally maintained cdpk3 gene, restoring mosquito transmission to wild-type level. cdpk3- ookinetes maintain their full genetic differentiation potential when microinjected into the mosquito haemocoel and cdpk3- sporozoites produced in this way are motile and infectious, suggesting an ookinete-limited essential function for CDPK3.
- Published
- 2016
26. Stage-specific depletion of myosin A supports an essential role in motility of malarial ookinetes
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Jacqueline Mendoza, Markus Ganter, Kai Matuschewski, Marion Hliscs, Christos Louis, Inga Siden-Kiamos, Robert E. Sinden, Andreas Kunze, and Marion Steinbüchel
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Genetics ,Gliding motility ,Immunology ,Mutant ,Anopheles ,Biology ,biology.organism_classification ,Microbiology ,Plasmodium ,Cell biology ,Schizogony ,Virology ,parasitic diseases ,Myosin ,Plasmodium berghei ,Apical membrane antigen 1 - Abstract
Summary Functional analysis of Plasmodium genes by clas- sical reverse genetics is currently limited to mutants that are viable during erythrocytic schizogony, the pathogenic phase of the malaria parasite where transfection is performed. Here, we describe a conceptually simple experimental approach to study the function of genes essential to the asexual blood stages in a subsequent life cycle stage by a promoter-swap approach. As a proof of concept we targeted the unconventional class XIV myosin MyoA, which is known to be required for Toxoplasma gondii tachyzoite loco- motion and host cell invasion. By placing the cor- responding Plasmodium berghei gene, PbMyoA, under the control of the apical membrane antigen 1 (AMA1) promoter, expression in blood stages is maintained but switched off during transmission to the insect vector, i.e. ookinetes. In those mutant ookinetes gliding motility is entirely abolished resulting in a complete block of life cycle progres- sion in Anopheles mosquitoes. Similar approaches should permit the analysis of gene function in the mosquito forms that are shared with the erythro- cytic stages of the malaria parasite.
- Published
- 2011
- Full Text
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27. Critical role for a stage-specific actin in male exflagellation of the malaria parasite
- Author
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Kai Matuschewski, Alice Laforge, Herwig Schüler, Rhiannon N. Morgan, Christos Louis, Carolin Nahar, Lucia Bertuccini, Taco W. A. Kooij, Elena Deligianni, Nikos Poulakakis, and Inga Siden-Kiamos
- Subjects
Axoneme ,biology ,Immunology ,Arp2/3 complex ,macromolecular substances ,biology.organism_classification ,Microbiology ,Cell biology ,Profilin ,Cytoplasm ,Virology ,parasitic diseases ,Gametocyte ,biology.protein ,Plasmodium berghei ,Actin ,Gametogenesis - Abstract
Male gametogenesis occurs directly after uptake of malaria parasites by the mosquito vector and leads to the release of eight nucleated flagellar gametes. Here, we report that one of the two parasite actin isoforms, named actin II, is essential for this process. Disruption of actin II in Plasmodium berghei resulted in viable asexual blood stages, but male gametogenesis was specifically inhibited. Upon activation, male gametocyte DNA was replicated normally and axonemes assembled, but egress from the host cell was inhibited, and axoneme motility abolished. The major actin isoform, actin I, displayed dual localization to the cytoplasm and the nucleus in male gametocytes. After activation actin I was found to be restricted to the cytoplasm. In actII(-) mutant parasites, this re-localization was abolished and actin I remained in both cellular compartments. These findings reveal vital and pleiotropic functions for the actin II isoform in male gametogenesis of the malaria parasite.
- Published
- 2011
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28. Egress ofPlasmodium bergheigametes from their host erythrocyte is mediated by the MDV-1/PEG3 protein
- Author
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Lucia Bertuccini, Marta Ponzi, Eliane C. Laurentino, Christos Louis, Grazia Camarda, Chris J. Janse, Tomasino Pace, Hans Kroeze, Inga Siden-Kiamos, Pietro Alano, Chiara Currà, Blandine Franke-Fayard, and Andrew P. Waters
- Subjects
Male ,Erythrocytes ,Cell division ,Plasmodium berghei ,Genes, Protozoan ,Immunology ,Protozoan Proteins ,Asexual reproduction ,Microbiology ,Plasmodium ,Mice ,Sex Factors ,Microscopy, Electron, Transmission ,Sequence Analysis, Protein ,Virology ,Anopheles ,parasitic diseases ,Gametocyte ,Animals ,Zygote ,biology ,Plasmodium falciparum ,biology.organism_classification ,Malaria ,Cell biology ,Germ Cells ,Fertilization ,Host-Pathogen Interactions ,Female - Abstract
Malaria parasites invade erythrocytes of their host both for asexual multiplication and for differentiation to male and female gametocytes - the precursor cells of Plasmodium gametes. For further development the parasite is dependent on efficient release of the asexual daughter cells and of the gametes from the host erythrocyte. How malarial parasites exit their host cells remains largely unknown. We here report the characterization of a Plasmodium berghei protein that is involved in egress of both male and female gametes from the host erythrocyte. Protein MDV-1/PEG3, like its Plasmodium falciparum orthologue, is present in gametocytes of both sexes, but more abundant in the female, where it is associated with dense granular organelles, the osmiophilic bodies. Deltamdv-1/peg3 parasites in which MDV-1/PEG3 production was abolished by gene disruption had a strongly reduced capacity to form zygotes resulting from a reduced capability of both the male and female gametes to disrupt the surrounding parasitophorous vacuole and to egress from the host erythrocyte. These data demonstrate that emergence from the host cell of male and female gametes relies on a common, MDV-1/PEG3-dependent mechanism that is distinct from mechanisms used by asexual parasites.
- Published
- 2009
- Full Text
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29. VectorBase: a data resource for invertebrate vector genomics
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William M. Gelbart, Fotis C. Kafatos, Robert V. Bruggner, Peter W. Atkinson, Ryan Butler, Nora J. Besansky, Karyn Megy, Scott Christley, Frank H. Collins, Peter Arensburger, Jason M. Meyer, Daniel Lawson, George K. Christophides, Robert M. MacCallum, Nathan Konopinski, Pantelis Topalis, Martin Hammond, Catherine A. Hill, Gregory R. Madey, Emmanuel Dialynas, Kathryn S. Campbell, Eric O. Stinson, David W. Severson, Christos Louis, Neil F. Lobo, Seth Redmond, and Ewan Birney
- Subjects
Anopheles gambiae ,030231 tropical medicine ,Genome, Insect ,Genomics ,Computational biology ,Pediculus humanus ,03 medical and health sciences ,0302 clinical medicine ,Aedes ,parasitic diseases ,Anopheles ,Databases, Genetic ,Genetics ,Animals ,030304 developmental biology ,0303 health sciences ,biology ,Ixodes ,Ecology ,Gene Expression Profiling ,Arthropod Vectors ,Pediculus ,Articles ,biology.organism_classification ,3. Good health ,Culex ,Culicidae ,Vocabulary, Controlled ,Ixodes scapularis ,Vector (epidemiology) ,Arthropod Vector - Abstract
VectorBase (http://www.vectorbase.org) is an NIAID-funded Bioinformatic Resource Center focused on invertebrate vectors of human pathogens. VectorBase annotates and curates vector genomes providing a web accessible integrated resource for the research community. Currently, VectorBase contains genome information for three mosquito species: Aedes aegypti, Anopheles gambiae and Culex quinquefasciatus, a body louse Pediculus humanus and a tick species Ixodes scapularis. Since our last report VectorBase has initiated a community annotation system, a microarray and gene expression repository and controlled vocabularies for anatomy and insecticide resistance. We have continued to develop both the software infrastructure and tools for interrogating the stored data.
- Published
- 2008
30. Intracellular calcium levels in thePlasmodium bergheiookinete
- Author
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Christos Louis and Inga Siden-Kiamos
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Plasmodium berghei ,Motility ,chemistry.chemical_element ,Calcium ,Calcium in biology ,Cell Line ,Apicomplexa ,chemistry.chemical_compound ,Calcium imaging ,BAPTA ,Aedes ,Cell Movement ,parasitic diseases ,Animals ,Calcimycin ,Ionophores ,biology ,Oocysts ,biology.organism_classification ,Cell biology ,Infectious Diseases ,chemistry ,Animal Science and Zoology ,Parasitology ,Intracellular - Abstract
SUMMARYOokinetes are the motile and invasive stages ofPlasmodiumparasites in the mosquito host. Here we explore the role of intracellular Ca2+in ookinete survival and motility as well as in the formation of oocystsin vitroin the rodent malaria parasitePlasmodium berghei. Treatment with the Ca2+ionophore A23187 induced death of the parasite, an effect that could be prevented if the ookinetes were co-incubated with insect cells before incubation with the ionophore. Treatment with the intracellular calcium chelator BAPTA/AM resulted in increased formation of oocystsin vitro. Calcium imaging in the ookinete using fluorescent calcium indicators revealed that the purified ookinetes have an intracellular calcium concentration in the range of 100 nm. Intracellular calcium levels decreased substantially when the ookinetes were incubated with insect cells and their motility was concomitantly increased. Our results suggest a pleiotropic role for intracellular calcium in the ookinete.
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- 2008
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31. Evolution of Mesobuthus gibbosus (Brullé, 1832) (Scorpiones: Buthidae) in the northeastern Mediterranean region
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Aristeidis Parmakelis, Iasmi Stathi, Lefteris Spanos, Christos Louis, Moysis Mylonas, Maria Chatzaki, and Stylianos Michail Simaiakis
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Mediterranean climate ,Phylogeography ,Range (biology) ,Genus ,Buthidae ,Ecology ,Genetics ,Vicariance ,Period (geology) ,Mesobuthus ,Biology ,biology.organism_classification ,Ecology, Evolution, Behavior and Systematics - Abstract
Sequence data derived from two mitochondrial markers, 16S rRNA and COI genes, were used to infer the evolutionary history of 47 insular and mainland populations covering most of the distributional range of the northeastern Mediterranean scorpion species Mesobuthus gibbosus. Based on the estimated divergence times of Mesobuthus lineages, the temporal frame of the genus differentiation in the northeastern Mediterranean region is placed in middle Miocene (15 million years ago). The biogeographic affinities of M. gibbosus populations point towards a mainly vicariant pattern of differentiation of the species which is consistent with the geological events that transformed the Aegean region during the period from 12 to 5 million years ago. M. gibbosus is an old northeastern Mediterranean species that has retained valuable bits of genetic information, reflecting some of the oldest vicariant events that have occurred in the area. Most importantly, the history witnessed by M. gibbosus has not been obscured by more recent palaeoevents of the region. Therefore, the case of M. gibbosus is in favour of a taxon-oriented 'perception' of the natural history of a given area.
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- 2006
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32. Phylogeography of Iurus dufoureius (Brulle, 1832) (Scorpiones, Iuridae)
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Christos Louis, Iasmi Stathi, Moysis Mylonas, Aristeidis Parmakelis, and L. Spanos
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Phylogeography ,Ecology ,Phylogenetic tree ,Evolutionary biology ,Genus ,Molecular phylogenetics ,Vicariance ,Biology ,Subspecies ,Clade ,Ecology, Evolution, Behavior and Systematics ,Maximum parsimony - Abstract
Aim This study uses molecular data in conjunction with palaeogeography to infer the most plausible biogeographical scenario accounting for the current distributional pattern of Iurus dufoureius. Location North-eastern Mediterranean region. Methods Sequencing of a 441-bp segment of the mitochondrial 16S rRNA gene in seven populations covering the whole distributional range of the species. Phylogenetic analyses performed included neighbour joining, maximum parsimony and Bayesian inference. Results The molecular phylogeny showed that two Iurus clades are strongly supported. These clades correspond to the two subspecies Iurus dufoureius dufoureius and Iurus dufoureius asiaticus, currently recognized within the genus. The assumption of a clock-like evolution could not be rejected, and this enabled us to estimate an approximation of the local rate of evolution for the I. dufoureius lineages. Based on the estimated evolutionary rate (0.79 ± 0.17 Myr−1), the split between the two Iurus clades occurred c. 8 Ma. Main conclusions Contrary to what was believed in the past, the genus Iurus is an old north-eastern Mediterranean genus that has been differentiating in southern Greece and south-west Turkey at least from the middle Miocene. According to the phylogenetic trees obtained and the dating of the divergence times of lineages, the genus dispersed into the Aegean Archipelago when the Aegean was still a uniform land mass. Although the phylogenetic relationships of I. d. dufoureius populations have been shaped by the most recent vicariant events, the phylogenetic relationships of I. d. asiaticus populations are mostly attributable to older palaeoevents occurring in the area.
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- 2006
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33. Gene expression in insecticide resistant and susceptible Anopheles gambiae strains constitutively or after insecticide exposure
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Janet Hemingway, Jean-Philippe David, Hilary Ranson, Anastasios C. Koutsos, Fotis C. Kafatos, Claudia Blass, Christos Louis, John Vontas, George K. Christophides, Institute of Molecular Biology and Biotechnology (IMBB-FORTH), Foundation for Research and Technology - Hellas (FORTH), Vector Research Group, Liverpool School of Tropical Medicine (LSTM), European Molecular Biology Laboratory [Heidelberg] (EMBL), Laboratoire d'Ecologie Alpine (LECA), Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry]), Department of Biology, and University of Crete [Heraklion] (UOC)
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0106 biological sciences ,Insecticides ,Anopheles gambiae ,01 natural sciences ,molecular characterization ,Carboxylesterase ,chemistry.chemical_compound ,malaria vector ,culex-quinquefasciatus ,Glutathione s-transferases ,Expressed Sequence Tags ,[SDV.EE]Life Sciences [q-bio]/Ecology, environment ,Genetics ,0303 health sciences ,Expressed sequence tag ,Pyrethroid ,insecticide resistance ,drosophila ,3. Good health ,Insect Proteins ,nilaparvata-lugens ,microarray ,medicine.drug ,[SDV.BID]Life Sciences [q-bio]/Biodiversity ,Biology ,03 medical and health sciences ,pyrethroids ,Anopheles ,parasitic diseases ,medicine ,Animals ,detoxification ,Molecular Biology ,Gene ,Permethrin ,030304 developmental biology ,Gene Expression Profiling ,Cytochrome P450 ,biology.organism_classification ,p450 ,[SDE.ES]Environmental Sciences/Environmental and Society ,ddt ,Gene expression profiling ,010602 entomology ,Gene Expression Regulation ,chemistry ,Insect Science ,biology.protein ,identification ,[SDE.BE]Environmental Sciences/Biodiversity and Ecology - Abstract
International audience; A microarray containing approximately 20 000 expressed sequence tags (ESTs; 11 760 unique EST clusters) from the malaria vector, Anopheles gambiae, was used to monitor differences in global gene expression in two insecticide resistant and one susceptible strains. Statistical analysis identified 77 ESTs that were differentially transcribed among the three strains. These include the cytochrome P450 CYP314A1, over-transcribed in the DDT resistant ZAN/U strain, and many genes that belong to families not usually associated with insecticide resistance, such as peptidases, sodium/calcium exchangers and genes implicated in lipid and carbohydrate metabolism. Short-term (6 and 10 h) effects of exposure of the pyrethroid resistant RSP strain to permethrin were also detected. Several genes belonging to enzyme families already implicated in insecticide or xenobiotic detoxification were induced, including the carboxylesterase COEAE2F gene and members of the UDP-glucuronosyl transferase and nitrilase families.
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- 2005
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34. AnoBase: a genetic and biological database of anophelines
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C. Kiamos, L K Hope, Janet Hemingway, Anastasios C. Koutsos, Emmanuel Dialynas, Clare Strode, Pantelis Topalis, and Christos Louis
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biology ,business.industry ,Relational database ,Anopheles gambiae ,Biological database ,Genetic data ,Genomics ,Computational biology ,biology.organism_classification ,Genome ,Genomic databases ,Biotechnology ,Insecticide resistance ,Insect Science ,parasitic diseases ,Genetics ,business ,Molecular Biology - Abstract
AnoBase (http://www.anobase.org) is an integrated, relational database of basic biological and genetic data on anopheline species, with a particular emphasis on Anopheles gambiae. It has been designed as an information source and research support tool for the broad vector biology community. Although AnoBase is not a primary genomic database that develops and provides tools to access the genome of the malaria mosquito, it nevertheless contains several sections that offer data of genomic interest such as in situ hybridization images, an integrated gene tool and direct online access to AnoXcel, the proteomic database of An. gambiae. Moreover, AnoBase also contains information on non-gambiae mosquito species and a novel section on studies related to insecticide resistance.
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- 2005
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35. Plasmodium berghei ookinetes bind to Anopheles gambiae and Drosophila melanogaster annexins
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Robert E. Sinden, Christos Louis, Inga Siden-Kiamos, Laurence Ehret-Sabatier, Jaqueline Mendoza, and Michalis Kotsyfakis
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biology ,Anopheles gambiae ,fungi ,Midgut ,biology.organism_classification ,Microbiology ,Biochemistry ,Annexin ,Drosophilidae ,parasitic diseases ,Botany ,Melanogaster ,Plasmodium berghei ,Drosophila melanogaster ,Molecular Biology ,Peptide sequence - Abstract
Using a proteomic approach we identified polypeptides from Anopheles gambiae and Drosophila melanogaster protein extracts that selectively bind purified Plasmodium berghei ookinetes in vitro; these were two and three distinct polypeptides, respectively, with an apparent molecular weight of about 36 kDa. Combining two-dimensional electrophoresis and MALDI-TOF (matrix-associated laser desorption ionization time of flight) mass spectrometry we determined that the polypeptides correspond to isomorphs of the annexin B11 protein of the fruit fly. When protein extracts derived from A. gambiae and D. melanogaster tissue culture cells were further fractionated, the binding activity matching the annexin protein could be localized in the fraction derived from cell membranes in both diptera. Antibody staining showed that annexin also binds to ookinetes during the invasion of the mosquito midgut. Finally, inclusion of antiannexin antisera in a mosquito blood meal impaired parasite development, suggesting a facilitating role for annexins in the infection of the mosquito by Plasmodium.
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- 2005
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36. Gene expression in Plasmodium berghei ookinetes and early oocysts in a co-culture system with mosquito cells
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Giorgos Papagiannakis, Christos Louis, John Vontas, Marianna Karras, Inga Siden-Kiamos, and Andrew P. Waters
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Plasmodium berghei ,Genes, Protozoan ,Gene Expression ,Biology ,Gene expression ,Protein biosynthesis ,Parasite hosting ,Animals ,Cluster Analysis ,Gene ,Molecular Biology ,Cells, Cultured ,Oligonucleotide Array Sequence Analysis ,Developmental profile ,Life Cycle Stages ,Gene Expression Profiling ,Epithelial Cells ,biology.organism_classification ,Coculture Techniques ,Cell biology ,Culicidae ,Protein Biosynthesis ,Gene chip analysis ,Parasitology ,DNA microarray ,Energy Metabolism - Abstract
Using an in vitro development system for Plasmodium berghei sporogonic stages and microarray technology we examined parasite gene expression during ookinete invasion of Aedes cells and the ensuing oocyst development. A number of genes were found to be differentially expressed. The most prominent class of up-regulated elements corresponded to products involved in protein synthesis and metabolism. Furthermore, several previously studied genes with a known in vivo developmental profile matched published data. A large number of genes with a hitherto unknown function during the life cycle stages studied also show a differential pattern of expression, indicating the involvement of their products in control and execution of active developmental processes.
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- 2005
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37. Isolation and Characterization of hnRNA-snRNA-Protein Complexes from Morris Hepatoma Cells
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Angel Alonso, Christos Louis, Angela Prüsse, and Constantin E. Sekeris
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Male ,Chemical Phenomena ,RNase P ,Sodium ,chemistry.chemical_element ,Sodium Chloride ,Biology ,Biochemistry ,Liver Neoplasms, Experimental ,Ribonucleases ,RNA, Small Nuclear ,Animals ,RNA, Neoplasm ,Nuclear protein ,Polyacrylamide gel electrophoresis ,Incubation ,Cells, Cultured ,Cell Nucleus ,RNA ,Rats, Inbred Strains ,Molecular biology ,Neoplasm Proteins ,Rats ,Chemistry ,Nucleoproteins ,Ribonucleoproteins ,chemistry ,RNA, Heterogeneous Nuclear ,Electrophoresis, Polyacrylamide Gel ,Precursor mRNA ,Small nuclear RNA - Abstract
Of the RNA labelled after incubation of hepatoma cells with radioactive precursors for 20 and 150 min. 35% and 70%, respectively, can be isolated from nuclei by two consecutive extractions with 0.14 M NaCl at pH 8. The isolated RNA is complexed with nuclear proteins forming structures with sedimentation coefficients of less than 30 S to greater than 100 S. Similar complexes from rat liver isolated under the same experimental conditions show coefficients of 30-40 S. The RNA-associated proteins are similar, on the basis of sodium dodecyl sulphate/polyacrylamide gel electrophoresis, to the respective proteins of other cell types. The presence on these RNP complexes of six discrete small nuclear RNAs (snRNA) has been established. Experiments with a reversible inhibitor of RNA synthesis, D-galactosamine, demonstrated, differences in the turnover of hnRNA and snRNA. The half-lives of the six snRNA species has been determined, varying from 32 h for snRNA species a, b and d, to 22 h for snRNA species e and f and to 13 h for snRNA species c. Treatment of the nuclear extracts with 0.7 M and 1 M NaCl results in dissociation of hnRNA from the 'core' and other polypeptides, whereas snRNA remains complexed with polypeptides of Mr 54 000-59 000. Incubation of the nuclear extracts at 0 C with low doses of pancreatic R Nase (up to 1.5 micrograms/ml), which renders approximately 80% of the hnRNA acid-soluble and cleaves most of the snRNA, results in conversion of the high-molecular-weight hnRNPs to 30-S structures, without disrupting the 30-S RNP. Treatment of the nuclear extracts with higher doses of RNase (3 micrograms/ml) leads to disruption of the 30-S RNP and release of the hnRNA-associated proteins, underlining the importance of hnRNA-protein interaction for the retainment of the hnRNP structures.
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- 2005
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38. Close association of invadingPlasmodium berghei and β integrin in theAnopheles gambiae midgut
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Gareth Lycett, Vasso Mahairaki, Robert E. Sinden, Inga Siden-Kiamos, and Christos Louis
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Integrin beta Chains ,Plasmodium berghei ,Physiology ,Anopheles gambiae ,Blotting, Western ,Genetic Vectors ,Integrin ,Biochemistry ,Host-Parasite Interactions ,Laminin ,Anopheles ,parasitic diseases ,Escherichia coli ,medicine ,Animals ,Microscopy, Confocal ,biology ,Oocysts ,Epithelial Cells ,Midgut ,General Medicine ,biology.organism_classification ,Immunohistochemistry ,Virology ,Epithelium ,Cell biology ,medicine.anatomical_structure ,Insect Science ,biology.protein ,Basal lamina ,Digestive System - Abstract
We have used confocal microscopy and an antibody against Anopheles gambiae beta integrin to study this protein's distribution in the mosquito midgut and its relationship to invading Plasmodium berghei parasites. An extensive reorganization of integrin is seen to take place in the midgut epithelial cells following the uptake of either non-infected or parasite-infected blood meal, probably reflecting the reshaping of the gut due to the presence of the food bolus and the peritrophic membrane that surrounds it. Furthermore, malaria parasites are coated with beta integrin immediately upon entry into the epithelium, independent of whether they develop intra- or extracellularly. Although this coat is shed a few days after the invasion, beta integrin remains concentrated in the cells surrounding the maturing oocyst for several days. Finally, the antibody detects a structural change in the midgut epithelial cells in the immediate vicinity of the invading ookinete, which is consistent with Plasmodium-induced apoptosis followed by wound healing. This intimate association suggests a specific role of beta integrin in the invasion process.
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- 2005
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39. Does environmental stress affect insect-vectored parasite transmission?
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John Vontas, Hilary Hurd, Janet Hemingway, L. McCarroll, Christos Louis, and S. H. P. P. Karunaratne
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education.field_of_study ,Natural selection ,biology ,Physiology ,media_common.quotation_subject ,fungi ,Population ,Anopheles ,Longevity ,Zoology ,Insect ,biology.organism_classification ,medicine.disease ,Virology ,Article ,Cutaneous leishmaniasis ,Insect Science ,medicine ,Parasite hosting ,Leishmania major ,education ,Ecology, Evolution, Behavior and Systematics ,media_common - Abstract
In some insects, the cost of parasitic infection can be sufficient to elicit natural selection against competent hosts (Yan et al., 1997). This tendency may be compensated for by increased parasite susceptibility being linked to environmental stress. Obvious examples of variable environmental stress include insecticide selection from disease control operations and seasonal stress through heat and dehydration in some insect species. Vectorial capacity (i.e. the ability of mosquitoes to ingest parasites and to promote their maturation until the infective stage) and the rate of insect survival until parasite maturation (Failloux et al., 1995), can differ geographically according to insect strain (Crans, 1973; McGreevy et al., 1982). The sandfly, Phlebotomus papatasi, transmits cutaneous leishmaniasis in desert and savannah regions of the Old World, where seasonal stress and dehydration reduces the quantity of sugar in plant leaves that is available for insect feeding. Selection for hunger tolerance has produced a population of P. papatasi that has sufficient longevity from feeding on the sugar depleted leaves to deposit their eggs and transmit Leishmania (Schlein & Jacobson, 2000). This inherited trait may alter the insects' physiology and disrupt the interaction between insect and parasite, altering the insects' susceptibility to infection. A similar effect of selection for hunger tolerance on susceptibility to Leishmania major infection occurs in Jordanian P. papatasi (Schlein & Jacobson, 2001).
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- 2004
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40. The Anopheles gambiae genome: an update
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Ewan Birney, Emmanuel Mongin, Frank H. Collins, Robert A. Holt, and Christos Louis
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Genetics ,Whole genome sequencing ,Chromosomes, Artificial, Bacterial ,Genome ,Anopheles gambiae ,Chromosome Mapping ,Computational Biology ,Genetic Variation ,Sequence assembly ,Gene Annotation ,Computational biology ,Biology ,biology.organism_classification ,Annotation ,Infectious Diseases ,Anopheles ,Animals ,Parasitology ,In Situ Hybridization - Abstract
As a result of an international collaborative effort, the first draft of the Anopheles gambiae genome sequence and its preliminary annotation were published in October 2002. Since then, the assembly, annotation and means of accession of the An. gambiae genome have been under continuous development. This article reviews progress and considers limitations in the current sequence assembly and gene annotation, as well as approaches to address these problems and outstanding issues that users of the data must bear in mind.
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- 2004
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41. SOAP, a novel malaria ookinete protein involved in mosquito midgut invasion and oocyst development
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Johannes T. Dessens, Dina Vlachou, Xiao Jin Xu, Robert E. Sinden, Jacqui Mendoza, Inga Siden-Kiamos, George Dimopoulos, Vassiliki Mahairaki, Fotis C. Kafatos, Emad I.M. Khater, and Christos Louis
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biology ,fungi ,Anopheles ,Midgut ,medicine.disease ,biology.organism_classification ,Microbiology ,Cell biology ,medicine.anatomical_structure ,Laminin ,parasitic diseases ,Immunology ,medicine ,biology.protein ,Parasite hosting ,Basal lamina ,Plasmodium berghei ,Molecular Biology ,Peptide sequence ,Malaria - Abstract
An essential, but poorly understood part of malaria transmission by mosquitoes is the development of the ookinetes into the sporozoite-producing oocysts on the mosquito midgut wall. For successful oocyst formation newly formed ookinetes in the midgut lumen must enter, traverse, and exit the midgut epithelium to reach the midgut basal lamina, processes collectively known as midgut invasion. After invasion ookinete-to-oocyst transition must occur, a process believed to require ookinete interactions with basal lamina components. Here, we report on a novel extracellular malaria protein expressed in ookinetes and young oocysts, named secreted ookinete adhesive protein (SOAP). The SOAP gene is highly conserved amongst Plasmodium species and appears to be unique to this genus. It encodes a predicted secreted and soluble protein with a modular structure composed of two unique cysteine-rich domains. Using the rodent malaria parasite Plasmodium berghei we show that SOAP is targeted to the micronemes and forms high molecular mass complexes via disulphide bonds. Moreover, SOAP interacts strongly with mosquito laminin in yeast-two-hybrid assays. Targeted disruption of the SOAP gene gives rise to ookinetes that are markedly impaired in their ability to invade the mosquito midgut and form oocysts. These results identify SOAP as a key molecule for ookinete-to-oocyst differentiation in mosquitoes.
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- 2003
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42. Mitochondrial DNA phylogeny and morphological diversity in the genus Mastus (Beck, 1837): a study in a recent (Holocene) island group (Koufonisi, south-east Crete)
- Author
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G. Papagiannakis, Aristeidis Parmakelis, E. Spanos, Moysis Mylonas, and Christos Louis
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Genetic diversity ,Mitochondrial DNA ,Natural selection ,biology ,Phylogenetics ,Gastropoda ,Land snail ,Zoology ,biology.organism_classification ,Mollusca ,Ecology, Evolution, Behavior and Systematics ,Holocene - Abstract
Three endemic Cretan land snail species of the genus Mastus (Beck, 1837) from the island group of Koufonisi (south-east Crete) and the eastern part of Crete, were studied by multivariate analysis of shell morphology and analysis of mtDNA sequences. The phylogeny of the populations studied and the processes effecting the genetic and morphological diversity of the species were investigated. Extremely high mtDNA sequence divergence was observed both within and between populations. The Cretan populations could not be distinguished morphologically, while the populations of the islets were more distinct. We argue that the active geological past of the area (including sea level changes) and the long-term presence of humans has produced a mixing up of Mastus populations leading to the accumulation of high divergence of mtDNA sequences on a small spatial scale. The limited morphological diversity and the distinct shell ‘identity’ of the islets’ populations can be attributed to the selective pressures of the island group. © 2003 The Linnean Society of London, Biological Journal of the Linnean Society, 2003, 78, 383–399.
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- 2003
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43. Describing the breakbone fever: IDODEN, an ontology for dengue fever
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Vicky Dritsou, Pantelis Topalis, Emmanuel Dialynas, Christos Louis, and Elvira Mitraka
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lcsh:Arctic medicine. Tropical medicine ,Databases, Factual ,Computer science ,lcsh:RC955-962 ,Interoperability ,Dengue virus ,Ontology (information science) ,Bioinformatics ,medicine.disease_cause ,Dengue fever ,World Wide Web ,Dengue ,Controlled vocabulary ,medicine ,Animals ,Humans ,business.industry ,lcsh:Public aspects of medicine ,Public Health, Environmental and Occupational Health ,Information technology ,Biological Ontologies ,lcsh:RA1-1270 ,medicine.disease ,Toolbox ,3. Good health ,Infectious Diseases ,business ,Software ,Research Article - Abstract
Background Ontologies represent powerful tools in information technology because they enhance interoperability and facilitate, among other things, the construction of optimized search engines. To address the need to expand the toolbox available for the control and prevention of vector-borne diseases we embarked on the construction of specific ontologies. We present here IDODEN, an ontology that describes dengue fever, one of the globally most important diseases that are transmitted by mosquitoes. Methodology/Principal Findings We constructed IDODEN using open source software, and modeled it on IDOMAL, the malaria ontology developed previously. IDODEN covers all aspects of dengue fever, such as disease biology, epidemiology and clinical features. Moreover, it covers all facets of dengue entomology. IDODEN, which is freely available, can now be used for the annotation of dengue-related data and, in addition to its use for modeling, it can be utilized for the construction of other dedicated IT tools such as decision support systems. Conclusions/Significance The availability of the dengue ontology will enable databases hosting dengue-associated data and decision-support systems for that disease to perform most efficiently and to link their own data to those stored in other independent repositories, in an architecture- and software-independent manner., Author Summary The need for the construction of a dengue ontology arose through the fact that the incidence of dengue fever is on the rise across the world; the number of cases may be three to four times higher than the 100 million estimated by the WHO and a vaccine is still not available in spite of the significant efforts undertaken. Thus, control of dengue fever still relies mostly on controlling its mosquito vectors. Large amounts of entomological, epidemiological and clinical data are generated; these need to be efficiently organized in order to further our comprehension of the disease and its control. IDODEN aims to cover the different aspects and intricacies of dengue fever and syndromes caused by dengue virus(es). It contains more than 5000 terms describing epidemiological data, vaccine development, clinical features, the disease course, and more. We show here that it can be a helpful tool for researchers and that, in addition to allowing sophisticated search strategies, it is also useful for tasks such as modeling.
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- 2015
44. A draft genome sequence of an invasive mosquito: an Italian Aedes albopictus
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Roberta Spaccapelo, Francesca Scolari, Philippos Aris Papathanos, Ludvik M. Gomulski, Grazia Savini, Valerio Napolioni, Fabrizio Lombardo, Pantelis Topalis, Daniel Lawson, Giuliano Gasperi, Maurizio Calvitti, José M. C. Ribeiro, Anna R. Malacrida, Christos Louis, Giuseppe Saccone, Vicky Dritsou, Elena Deligianni, Bruno Arcà, Daniel S.T. Hughes, Malcolm Hinsley, Nikolai Windbichler, Riccardo Moretti, G. Aprea, Francesca Crucianelli, Matteo Picciolini, Ann Hall, Alekos Simoni, Mosè Manni, Guido Favia, Andrea Crisanti, Marco Salvemini, Dritsou, Vicky, Topalis, Panteli, Windbichler, Nikolai, Simoni, Aleko, Hall, Ann, Lawson, Daniel, Hinsley, Malcolm, Hughes, Daniel, Napolioni, Valerio, Crucianelli, Francesca, Deligianni, Elena, Gasperi, Giuliano, Gomulski, Ludvik M, Savini, Grazia, Manni, Mosè, Scolari, Francesca, Malacrida, Anna R, Arcà, Bruno, Ribeiro, José M, Lombardo, Fabrizio, Saccone, Giuseppe, Salvemini, Marco, Moretti, Riccardo, Aprea, Giuseppe, Calvitti, Maurizio, Picciolini, Matteo, Papathanos, Philippos Ari, Spaccapelo, Roberta, Favia, Guido, Crisanti, Andrea, Louis, Christos, Aprea, G., Moretti, R., and Calvitti, M.
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Male ,Odorant binding ,Genome, Insect ,Sequence assembly ,Repetitive DNA ,Biology ,Microbiology ,Genome ,Transposable element ,DNA sequencing ,busco ,chikungunya ,dengue fever ,disease vector ,invasive species ,ngs ,repetitive dna ,transposable elements ,wgs ,parasitology ,infectious diseases ,public health, environmental and occupational health ,microbiology ,Open Reading Frames ,Aedes ,BUSCO ,Invasive species ,Disease vector ,Dengue fever ,Chikungunya ,Transposable elements ,WGS ,NGS ,Animals ,Gene ,Whole genome sequencing ,Genetics ,BUSCO, Chikungunya, Dengue fever, Disease vector, Invasive species, NGS, Repetitive DNA, Transposable elements, WGS ,environmental and occupational health ,public health ,fungi ,Invasive specie ,Public Health, Environmental and Occupational Health ,High-Throughput Nucleotide Sequencing ,Molecular Sequence Annotation ,General Medicine ,Original Articles ,Sequence Analysis, DNA ,biology.organism_classification ,Infectious Diseases ,Italy ,Sialome ,Parasitology ,Female - Abstract
The draft genome sequence of Italian specimens of the Asian tiger mosquito Aedes (Stegomyia) albopictus (Diptera: Culicidae) was determined using a standard NGS (next generation sequencing) approach. The size of the assembled genome is comparable to that of Aedes aegypti; the two mosquitoes are also similar as far as the high content of repetitive DNA is concerned, most of which is made up of transposable elements. Although, based on BUSCO (Benchmarking Universal Single-Copy Orthologues) analysis, the genome assembly reported here contains more than 99% of protein-coding genes, several of those are expected to be represented in the assembly in a fragmented state. We also present here the annotation of several families of genes (tRNA genes, miRNA genes, the sialome, genes involved in chromatin condensation, sex determination genes, odorant binding proteins and odorant receptors). These analyses confirm that the assembly can be used for the study of the biology of this invasive vector of disease. © W. S. Maney & Son Ltd 2015.
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- 2015
45. The Genome Sequence of the Malaria Mosquito Anopheles gambiae
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Mei Wang, Frank H. Collins, Yong Liang, José M. C. Ribeiro, Zhijian Tu, Jason R. Miller, Mark Yandell, Pantelis Topalis, Hongguang Shao, Qi Zhao, Hamilton O. Smith, Ali N Dana, Zhaoxi Ke, J. Craig Venter, Deborah R. Nusskern, Christos Louis, Ivica Letunic, Brian P. Walenz, Granger G. Sutton, Patrick Wincker, Anastasios C. Koutsos, Paul T. Brey, Ewan Birney, Jean Weissenbach, Fotis C. Kafatos, Cheryl A. Evans, Kerry J. Woodford, Dana Thomasova, Eugene W. Myers, Stephen L. Hoffman, Kokoza Eb, Josep F. Abril, Randall Bolanos, Megan A. Regier, Holly Baden, George K. Christophides, Véronique de Berardinis, Jingtao Sun, James R. Hogan, Kabir Chatuverdi, Ron Wides, Emmanuel Mongin, Igor F. Zhimulev, Steven L. Salzberg, Danita Baldwin, Richard J. Mural, Shiaoping C. Zhu, Anibal Cravchik, Jhy-Jhu Lin, G. Mani Subramanian, Young S. Hong, Shuang Cai, Francis Kalush, Rosane Charlab, Martin Wu, Claudia Blass, Mark Raymond Adams, Robert A. Holt, Clark M. Mobarry, Douglas B. Rusch, Michael Flanigan, Jim Biedler, Susanne L. Hladun, Ping Guan, Cynthia Sitter, Joel A. Malek, Mario Coluzzi, Cynthia Pfannkoch, Arthur L. Delcher, Alessandra della Torre, Maria F. Unger, Evgeny M. Zdobnov, Stephan Meister, Karin A. Remington, Peter W. Atkinson, Malcolm J. Gardner, Vladimir Benes, Ian M. Dew, Maria V. Sharakhova, X. Wang, Hongyu Zhang, Jian Wang, Jeffrey Hoover, Cheryl L. Kraft, Charles Roth, Andrew G. Clark, Shaying Zhao, Jyoti Shetty, Tina C. McIntosh, Aihui Wang, Zhiping Gu, Aaron L. Halpern, Anne Grundschober-Freimoser, David A. O'Brochta, Peter Arensburger, Brendan J. Loftus, Lucas Q. Ton, Véronique Anthouard, Mary Barnstead, John Lopez, Peer Bork, Didier Boscus, Michele Clamp, Jennifer R. Wortman, Claire M. Fraser, Lisa Friedli, William H. Majoros, Thomas J. Smith, Olivier Jaillon, Val Curwen, Samuel Broder, Sean D. Murphy, Roderic Guigó, Neil F. Lobo, Mathew A. Chrystal, Alison Yao, Alex Levitsky, Renee Strong, Maureen E. Hillenmeyer, Zhongwu Lai, Chinnappa D. Kodira, Rong Qi, and Zdobnov, Evgeny
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Chromosomes, Artificial, Bacterial ,Drosophila melanogaster/genetics ,Mosquito Control ,Proteome ,Enzymes/chemistry/genetics/metabolism ,Anopheles gambiae ,Genes, Insect ,Genome ,Plasmodium falciparum/growth & development ,Malaria, Falciparum ,Expressed Sequence Tags ,Genetics ,Expressed sequence tag ,Multidisciplinary ,Physical Chromosome Mapping ,Biological Evolution ,Enzymes ,Blood ,Drosophila melanogaster ,Insect Proteins ,Digestion ,Sequence analysis ,Molecular Sequence Data ,Plasmodium falciparum ,Biology ,Polymorphism, Single Nucleotide ,Species Specificity ,Anopheles ,Genetic variation ,Transcription Factors/chemistry/genetics/physiology ,Animals ,Humans ,Insect Proteins/chemistry/genetics/physiology ,Malaria, Falciparum/transmission ,Gene ,Anopheles/classification/genetics/parasitology/physiology ,Whole genome sequencing ,Haplotype ,Computational Biology ,Genetic Variation ,Feeding Behavior ,Sequence Analysis, DNA ,biology.organism_classification ,Insect Vectors ,Gene Expression Regulation ,Haplotypes ,Chromosome Inversion ,DNA Transposable Elements ,Insect Vectors/genetics/parasitology/physiology ,Transcription Factors - Abstract
Anopheles gambiae is the principal vector of malaria, a disease that afflicts more than 500 million people and causes more than 1 million deaths each year. Tenfold shotgun sequence coverage was obtained from the PEST strain of A. gambiae and assembled into scaffolds that span 278 million base pairs. A total of 91% of the genome was organized in 303 scaffolds; the largest scaffold was 23.1 million base pairs. There was substantial genetic variation within this strain, and the apparent existence of two haplotypes of approximately equal frequency (“dual haplotypes”) in a substantial fraction of the genome likely reflects the outbred nature of the PEST strain. The sequence produced a conservative inference of more than 400,000 single-nucleotide polymorphisms that showed a markedly bimodal density distribution. Analysis of the genome sequence revealed strong evidence for about 14,000 protein-encoding transcripts. Prominent expansions in specific families of proteins likely involved in cell adhesion and immunity were noted. An expressed sequence tag analysis of genes regulated by blood feeding provided insights into the physiological adaptations of a hematophagous insect.
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- 2002
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46. Mapping and identification of essential gene functions on the X chromosome of Drosophila
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Concepcion Ferraz, Phillipe Valenti, Hugo J. Bellen, Nicole Beinert, Valerie Lelaure, Beatriz de Pablos, Dana Borkova, Cathy Salles, Nadine S. Henderson, Christine Brun, Francis Galibert, David Harris, Edouard Cadieu, Wilfried Janning, Péter Deák, Paul J. McMillan, Panayiotis V. Benos, Robert D. C. Saunders, Foteini Mourkioti, Slava Bolshakov, Encarnación Madueño, Annette Peter, Alain Bucheton, George Papagiannakis, Sophie Vidal, Stéphanie Gloux, Lee Murphy, Belén Miñana, Gordon Dowe, Alain Billaud, Ulrich Schäfer, Debbie Callister, Lefteris Spanos, Yuchun He, David M. Glover, Evelyn Tait, Melanie K. Gatt, Lior Pachter, Herbert Jäckle, Lorna Campbell, Lore Dentzer, Meike Werner, Jacques Demaille, Inga Siden-Kiamos, Juan Modolell, Michael Ashburner, Robert Klapper, Fotis C. Kafatos, Christos Louis, Stéphanie Mottier, Peter Burkert, Petra Schöttler, Stéphane Dréano, and Bart Barrell
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Male ,Transposable element ,Chromosomes, Artificial, Bacterial ,Genome evolution ,X Chromosome ,Genes, Insect ,Genomics ,Biology ,Biochemistry ,Genome ,Contig Mapping ,P element ,Genetics ,Animals ,Molecular Biology ,Gene ,Genes, Essential ,Scientific Reports ,Chromosome Mapping ,Genome project ,Drosophila melanogaster ,Mutagenesis ,DNA Transposable Elements ,Female ,DNA Probes - Abstract
The Drosophila melanogaster genome consists of four chromosomes that contain 165 Mb of DNA, 120 Mb of which are euchromatic. The two Drosophila Genome Projects, in collaboration with Celera Genomics Systems, have sequenced the genome, complementing the previously established physical and genetic maps. In addition, the Berkeley Drosophila Genome Project has undertaken large-scale functional analysis based on mutagenesis by transposable P element insertions into autosomes. Here, we present a large-scale P element insertion screen for vital gene functions and a BAC tiling map for the X chromosome. A collection of 501 X-chromosomal P element insertion lines was used to map essential genes cytogenetically and to establish short sequence tags (STSs) linking the insertion sites to the genome. The distribution of the P element integration sites, the identified genes and transcription units as well as the expression patterns of the P-element-tagged enhancers is described and discussed.
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- 2002
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47. Genome-wide RIP-Chip analysis of translational repressor-bound mRNAs in the Plasmodium gametocyte
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Blandine Franke-Fayard, Christos Louis, Arnab Pain, Patricia A. G. C. Silva, Ana Guerreiro, Chris J. Janse, Celine Carret, Inga Siden-Kiamos, Jorge M. Santos, Elena Deligianni, and Gunnar R. Mair
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Plasmodium berghei ,Zygote ,Plasmodium falciparum ,Repressor ,RNA polymerase II ,RNA-binding protein ,03 medical and health sciences ,Transcription (biology) ,parasitic diseases ,Animals ,Humans ,RNA, Messenger ,Malaria, Falciparum ,Gene ,030304 developmental biology ,Genetics ,0303 health sciences ,biology ,Research ,030302 biochemistry & molecular biology ,RNA ,Gene Expression Regulation, Developmental ,RNA-Binding Proteins ,biology.organism_classification ,Microarray Analysis ,3. Good health ,Germ Cells ,biology.protein ,RIP-Chip ,Transcriptome - Abstract
Background Following fertilization, the early proteomes of metazoans are defined by the translation of stored but repressed transcripts; further embryonic development relies on de novo transcription of the zygotic genome. During sexual development of Plasmodium berghei, a rodent model for human malaria species including P. falciparum, the stability of repressed mRNAs requires the translational repressors DOZI and CITH. When these repressors are absent, Plasmodium zygote development and transmission to the mosquito vector is halted, as hundreds of transcripts become destabilized. However, which mRNAs are direct targets of these RNA binding proteins, and thus subject to translational repression, is unknown. Results We identify the maternal mRNA contribution to post-fertilization development of P. berghei using RNA immunoprecipitation and microarray analysis. We find that 731 mRNAs, approximately 50% of the transcriptome, are associated with DOZI and CITH, allowing zygote development to proceed in the absence of RNA polymerase II transcription. Using GFP-tagging, we validate the repression phenotype of selected genes and identify mRNAs relying on the 5′ untranslated region for translational control. Gene deletion reveals a novel protein located in the ookinete crystalloid with an essential function for sporozoite development. Conclusions Our study details for the first time the P. berghei maternal repressome. This mRNA population provides the developing ookinete with coding potential for key molecules required for life-cycle progression, and that are likely to be critical for the transmission of the malaria parasite from the rodent and the human host to the mosquito vector. Electronic supplementary material The online version of this article (doi:10.1186/s13059-014-0493-0) contains supplementary material, which is available to authorized users.
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- 2014
48. Non-coding RNA gene families in the genomes of anopheline mosquitoes
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Elena Deligianni, James E. Allen, Pantelis Topalis, Daniel Lawson, Nikos Poulakakis, Emmanuel Dialynas, Christos Louis, and Vicky Dritsou
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RNA, Untranslated ,Genome, Insect ,Molecular Sequence Data ,Computational biology ,Biology ,Genome ,RNA, Transfer ,Anopheles ,Genetics ,Animals ,RNA, Small Nucleolar ,Small nucleolar RNA ,Gene ,tRNA ,Phylogeny ,microRNA ,Small nuclear RNA ,Whole Genome Sequencing ,Base Sequence ,RNA ,Ribosomal RNA ,biology.organism_classification ,Non-coding RNA ,ncRNA ,3. Good health ,Genome evolution ,MicroRNAs ,Ribosomal genes ,RNA, Ribosomal ,Multigene Family ,Sequence Alignment ,Biotechnology ,Research Article - Abstract
Background Only a small fraction of the mosquito species of the genus Anopheles are able to transmit malaria, one of the biggest killer diseases of poverty, which is mostly prevalent in the tropics. This diversity has genetic, yet unknown, causes. In a further attempt to contribute to the elucidation of these variances, the international “Anopheles Genomes Cluster Consortium” project (a.k.a. “16 Anopheles genomes project”) was established, aiming at a comprehensive genomic analysis of several anopheline species, most of which are malaria vectors. In the frame of the international consortium carrying out this project our team studied the genes encoding families of non-coding RNAs (ncRNAs), concentrating on four classes: microRNA (miRNA), ribosomal RNA (rRNA), small nuclear RNA (snRNA), and in particular small nucleolar RNA (snoRNA) and, finally, transfer RNA (tRNA). Results Our analysis was carried out using, exclusively, computational approaches, and evaluating both the primary NGS reads as well as the respective genome assemblies produced by the consortium and stored in VectorBase; moreover, the results of RNAseq surveys in cases in which these were available and meaningful were also accessed in order to obtain supplementary data, as were “pre-genomic era” sequence data stored in nucleic acid databases. The investigation included the identification and analysis, in most species studied, of ncRNA genes belonging to several families, as well as the analysis of the evolutionary relations of some of those genes in cross-comparisons to other members of the genus Anopheles. Conclusions Our study led to the identification of members of these gene families in the majority of twenty different anopheline taxa. A set of tools for the study of the evolution and molecular biology of important disease vectors has, thus, been obtained. Electronic supplementary material The online version of this article (doi:10.1186/1471-2164-15-1038) contains supplementary material, which is available to authorized users.
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- 2014
49. Developmental variation in epidermal growth factor receptor size and localization in the malaria mosquito, Anopheles gambiae
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Claudia Blass, Gareth Lycett, and Christos Louis
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Genetics ,Messenger RNA ,biology ,Anopheles gambiae ,fungi ,biology.organism_classification ,medicine.disease ,Protein structure ,Insect Science ,parasitic diseases ,medicine ,biology.protein ,Epidermal growth factor receptor ,Molecular Biology ,Gene ,Tyrosine kinase ,Malaria ,Genomic organization - Abstract
The AGER gene encoding the epidermal growth factor receptor (EGFR) of the malaria mosquito Anopheles gambiae was cloned and sequenced. It represents a canonical member of this family of tyrosine kinase proteins exhibiting many similarities to orthologues from other species, both on the level of genomic organization and protein structure. The mRNA can be detected throughout development. Western analysis with an antibody raised against the extracellular domain of the mosquito protein suggests developmental variation in protein size and location that may be involved in the function of EGFR in the mosquito.
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- 2001
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50. Beta-integrin ofAnopheles gambiae: mRNA cloning and analysis of structure and expression
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Vasso Mahairaki, Gareth Lycett, Christos Louis, and Claudia Blass
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Cloning ,Messenger RNA ,biology ,Protein subunit ,Anopheles gambiae ,Integrin ,Midgut ,biology.organism_classification ,Molecular biology ,Insect Science ,parasitic diseases ,Genetics ,biology.protein ,Beta (finance) ,Molecular Biology ,Gene - Abstract
We have isolated an mRNA encoding a beta integrin subunit of the malaria mosquito Anopheles gambiae. Our analysis predicts a protein that is very similar to betaPS, the fruitfly orthologue. The gene is expressed during all developmental stages and it is found in all body parts, including the midgut. Finally, the expression of the gene does not seem to be modulated during blood meals, except for a substantial increase 48 h posthaematophagy, when digestion is nearly complete.
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- 2001
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