DOCSLIB.ORG

Molecular Characterization of Adult Diapause in the Northern House Mosquito, Culex Pipiens

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Molecular Characterization of Adult Diapause in the Northern House Mosquito, Culex Pipiens MOLECULAR CHARACTERIZATION OF ADULT DIAPAUSE IN THE NORTHERN HOUSE MOSQUITO, CULEX PIPIENS DISSERTATION Presented in Partial Fulfillment of the Requirements for the Degree Doctor of Philosophy in the Graduate School of The Ohio State University By Rebecca M. Robich, M.S. ***** The Ohio State University 2005 Dissertation Committee: Professor David L. Denlinger, Advisor Approved by Professor Donald H. Dean ________________________ Professor Glen R. Needham Advisor Graduate Program in Entomology Professor Brian H. Smith ABSTRACT In the northern United States, Culex pipiens (L.), a major avian vector of several arthropod-borne viruses, spends a good portion of the year in a state of developmental arrest (diapause). Although the physiological and hormonal aspects of Cx. pipiens diapause have been well-documented, there is little known on the molecular aspects of this important stage. Using suppressive subtractive hybridization (SSH), 40 genes differentially expressed in diapause were identified and their expression profiles were probed by northern blot hybridization. These genes have been classified into 8 distinct groupings: regulatory function, food utilization, stress response, metabolic function, cytoskeletal, ribosomal, transposable elements, and genes with unknown functions. Among 32 genes confirmed by northern blot hybridization, 6 are upregulated specifically in early diapause, 17 are upregulated in late diapause, and 2 are upregulated throughout diapause. In addition, 2 genes are diapause downregulated and 5 remained unchanged during diapause. Two regulatory genes upregulated in late diapause, ribosomal protein (rp) S3A and rpS6, are of particular interest for their potential involvement in developmental arrest. In other mosquito species, these genes are upregulated prior to oogenesis, and their suppression leads to a disruption in ovarian development. Since arrested ovarian development is a key characteristic of Cx. pipiens diapause, the lack of expression in early diapause may be key to this developmental ii arrest. Of equal interest is the upregulation of two stress-response genes in late diapause. The molecular chaperone, heat shock protein 23 (hsp23) is slightly upregulated in late diapause and may be involved in protecting females from environmental stresses. In addition, a gene encoding an enzyme involved in oxidizing certain insecticides in insecticide-resistant strains of Cx. quinquefasciatus, aldehyde oxidase, is strongly upregulated in Cx. pipiens late diapause. SSH and northern blot analysis also demonstrated the strong upregulation of a muscle-specific actin gene in Cx. pipiens early diapause. Although the upregulation of this cytoskeletal gene in early diapause may seem counterintuitive, females actively fly during diapause preparation in search of sugar meals and a protective site for overwintering. In addition, two ribosomal genes (large ribosomal subunit L18 and large ribosomal subunit) are upregulated in early diapause suggesting that their function is restricted to diapause preparation. Curiously, two genes encoding transposable elements, transposon T1-2 and Mimo-Cp2, are upregulated during late diapause in Cx. pipiens, but the function of these genes during diapause is unknown. Nine genes were also isolated by SSH with unknown identities, and all but one are upregulated in late diapause, as identified by northern blot hybridization In addition to the aforementioned genes, two genes encoding the blood digestive enzymes, trypsin and chymotrypsin-like, are downregulated in early diapause, and concurrently a gene associated with the accumulation of lipids, fatty acid synthase, is highly upregulated. As females enter diapause, fatty-acid synthase is only sporadically expressed, while the expression of trypsin and chymotrypsin-like remain undetectable iii until late diapause, when females prepare to take a blood meal upon diapause break. This is the first molecular evidence demonstrating that diapause in Cx. pipiens evokes a molecular switch from blood-feeding in nondiapausing individuals to sugar feeding in diapause-destined females. The increase in sugar feeding in diapause-destined Cx. pipiens and subsequent accumulation of lipid reserves likely requires a high amount of energy. This may be reflected in the upregulation of genes encoding two respiratory enzymes, cytochrome c oxidase subunit I (COI) and cytochrome c oxidase subunit III (COIII), during diapause preparation. Although transcript levels decline in mid-diapause when females enter an inactive state, levels again rise in late diapause, just prior to diapause break. There are no differences in mtDNA levels between nondiapausing and diapausing Cx. pipiens, thus suggesting that mitochondrial numbers are not reduced during diapause. Regulation of COI and COIII is thus likely to be under transcriptional control. In addition to genes obtained through SSH, heat shock protein 70 was isolated from Cx. pipiens by 5- and 3- rapid amplification of cDNA ends. This gene is upregulated upon heat shock and recovery from cold shock in diapausing and nondiapausing females, but is not upregulated as a component of the diapause program. However, diapausing females reared at 18°C survive cold exposure (-5°C) nearly twice as long as its nondiapausing counterparts reared at 18°C and 10 times as long as nondiapausing mosquitoes reared at 25°C. Diapausing females are also more desiccation resistant (1.6 to 2 fold) than nondiapausing females, regardless of rearing temperature. iv These results may be useful when comparing the molecular aspects of diapause across different taxa and developmental stages. In addition, this work may be helpful in understanding the transseasonal maintenance of viruses that utilize overwintering insects. v For Michael vi ACKNOWLEDGMENTS I am grateful to my advisor, David L. Denlinger, Ph.D., for his intellectual guidance and continued support for this project, and for his assistance in editing each chapter. I would like to thank my committee members, Drs. Donald H. Dean, Glen R. Needham, and Brian H. Smith, for their ideas and comments in bettering this thesis. I am also grateful for the assistance of Joseph P. Rinehart, Ph.D., and Linda Kitchen in helping to make this dissertation come together. I would like to thank those involved in the surveillance of West Nile virus in overwintering mosquitoes, including Richard Gary and Robert A. Restifo of the Ohio Department of Health's Vector-Borne Disease Program, and Joseph Lynch of the Cuyahoga County Board of Health. I appreciate the efforts of Woodbridge Foster, Ph.D., in helping to establish the Culex pipiens (Buckeye strain) colony, who collected the original larvae from his backyard in September 2000. vii VITA September 20, 1974 .…....... Born – Painesville, Ohio 1992 ..…………………..… Bachelor of Science, Environmental Biology Ohio University 1997-1998 .………………. Graduate Teaching Associate Ohio University 1998 .……………………... Master of Science, Environmental Studies Ohio University 1999-2000 .………………. Pre-Doctoral Fellow Virology Division U.S. Army Medical Research Institute of Infectious Diseases 2000-2004 .………………. Graduate Teaching and Research Associate The Ohio State University 2001 .……………………... Medical Entomology Summer Intern Ohio Department of Health PUBLICATIONS Moll, R.M., Romoser, W.S., Modrzakowski, M.C, Moncayo, A.C., and Lerdthusnee, K. 2001. Meconial peritrophic membranes and the fate of midgut bacteria during mosquito (Diptera: Culicidae) metamorphosis. Journal of Medical Entomology 38:29-32. Romoser, W.S., Moll, R.M., Moncayo, A.C., and Lerdthusnee, K. 2000. The occurrence and fate of the meconium and meconial peritrophic membranes in pupal and adult mosquitoes (Diptera: Culicidae). Journal of Medical Entomology 37:893-6. FIELDS OF STUDY Major Field: Entomology viii TABLE OF CONTENTS Abstract ………………………………………………………………………………….. ii Dedication ………………………………………………………………………………. vi Acknowledgements …………………………………………………………………...... vii Vita ……………………………………………………………………………………. viii List of Tables …………………………………………………………………………… xi List of Figures ………………………………………………………………………….. xii Chapters: 1. Introduction ……………………………………………………………………… 1 References ……………………………………………………………… 12 2. Diapause-specific gene expression in adults of the northern house mosquito, Culex pipiens L., identified by suppressive subtractive hybridization. Abstract ………………………………………………………………… 16 Introduction …………………………………………………………….. 17 Materials and Methods …………………………………………………. 19 Results ………………………………………………………………….. 23 Discussion ……………………………………………………………… 27 References ……………………………………………………………… 38 3. Diapause in the mosquito Culex pipiens evokes a metabolic switch that shuts down genes encoding blood digestive enzymes and upregulates a gene associated with sugar utilization and lipid storage. Abstract ………………………………………………………………… 49 Introduction …………………………………………………………….. 50 Materials and Methods …………………………………………….…… 52 Results ……………………………………………………………….…. 57 Discussion ……………………………………………………………… 63 References ……………………………………………………………… 69 ix 4. Downregulation of mitochondrial mRNA expression, but not mitochondrial number, during adult diapause in the northern house mosquito, Culex pipiens. Abstract ………………………………………………………………… 82 Introduction ………………………………………………………….…. 83 Materials and Methods ……………………………………………….… 85 Results ………………………………………………………………….. 90 Discussion ……………………………………………………………… 94 References ……………………………………………………………… 99 5. Enhanced cold and desiccation tolerance in diapausing adults of Culex pipiens, and a role for hsp70 in response
Load more

Recommended publications
  • Do Not Disturb Hibernating Bats Or Nursery Colonies Debbie C
    Part 2-Conservation, Management, Ethics: Buecher-Do Not Disturb Bats 43 Section A-Identifying and Protecting Cave Resources Do Not Disturb Hibernating Bats or Nursery Colonies Debbie C. Buecher In the United States, caving has increased in popularity during the last three decades. Unfortunately, human visitation in caves, even by the most conscientious cavers, gradually leaves negative impacts. Because we love our caves there is increasing awareness among the caving community toward performing ongoing restoration or building secure gates to maintain the integrity of caves we visit. However, we must consider the negative implications that our restoration efforts may have on the cave organisms adapted to this unique environment. Roosting Sites and Nursery Colonies Bats are extremely intolerant of human intrusion into their roosting sites (Mann and others 2002, Tuttle 1979) and roost disturbance over time can negatively impact population size (Mohr 1972). (See bat sensitivity, page 40.) Some people mistakenly believe that bats can use any cave or portion of a cave as their daily roosting area. Unfortunately this is not the case (Kunz 1982). Bats choose sites because ofa constrained range of tolerant temperature and humidity requirements-conditions that help insure their survival (McNab 1982). There are two extremely critical times in a bat's life when the roosting site is particularly important, during reproduction and during hibernation (Twente 1955). The location where female bats give birth and rear their young is called a maternity roost. For most temperate bat species that use caves, mating occurs in the fall, the bats then hibernatc until late spring, Figure t.
    [Show full text]
  • Host Selection by Culex Pipiens Mosquitoes and West Nile Virus Amplification
    Am. J. Trop. Med. Hyg., 80(2), 2009, pp. 268–278 Copyright © 2009 by The American Society of Tropical Medicine and Hygiene Host Selection by Culex pipiens Mosquitoes and West Nile Virus Amplification Gabriel L. Hamer , * Uriel D. Kitron, Tony L. Goldberg , Jeffrey D. Brawn, Scott R. Loss , Marilyn O. Ruiz, Daniel B. Hayes , and Edward D. Walker Department of Fisheries and Wildlife, and Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan; Department of Environmental Studies, Emory University, Atlanta, Georgia; Department of Pathobiological Sciences, University of Wisconsin, Madison, Wisconsin; Department of Natural Resources and Environmental Sciences, Program in Ecology, Evolution, and Conservation Biology, and Department of Pathobiology, University of Illinois, Champaign, Illinois; Conservation Biology Graduate Program, University of Minnesota, St. Paul, Minnesota Abstract. Recent field studies have suggested that the dynamics of West Nile virus (WNV) transmission are influenced strongly by a few key super spreader bird species that function both as primary blood hosts of the vector mosquitoes (in particular Culex pipiens ) and as reservoir-competent virus hosts. It has been hypothesized that human cases result from a shift in mosquito feeding from these key bird species to humans after abundance of the key birds species decreases. To test this paradigm, we performed a mosquito blood meal analysis integrating host-feeding patterns of Cx. pipiens , the principal vector of WNV in the eastern United States north of the latitude 36°N and other mosquito species with robust measures of host availability, to determine host selection in a WNV-endemic area of suburban Chicago, Illinois, during 2005–2007.
    [Show full text]
  • UMNP Mountains Manual 2017
    Mountain Adventures Manual utahmasternaturalist.org June 2017 UMN/Manual/2017-03pr Welcome to Utah Master Naturalist! Utah Master Naturalist was developed to help you initiate or continue your own personal journey to increase your understanding of, and appreciation for, Utah’s amazing natural world. We will explore and learn aBout the major ecosystems of Utah, the plant and animal communities that depend upon those systems, and our role in shaping our past, in determining our future, and as stewards of the land. Utah Master Naturalist is a certification program developed By Utah State University Extension with the partnership of more than 25 other organizations in Utah. The mission of Utah Master Naturalist is to develop well-informed volunteers and professionals who provide education, outreach, and service promoting stewardship of natural resources within their communities. Our goal, then, is to assist you in assisting others to develop a greater appreciation and respect for Utah’s Beautiful natural world. “When we see the land as a community to which we belong, we may begin to use it with love and respect.” - Aldo Leopold Participating in a Utah Master Naturalist course provides each of us opportunities to learn not only from the instructors and guest speaKers, But also from each other. We each arrive at a Utah Master Naturalist course with our own rich collection of knowledge and experiences, and we have a unique opportunity to share that Knowledge with each other. This helps us learn and grow not just as individuals, but together as a group with the understanding that there is always more to learn, and more to share.
    [Show full text]
  • Mosquitoes (Diptera: Culicidae) in the Dark—Highlighting the Importance of Genetically Identifying Mosquito Populations in Subterranean Environments of Central Europe
    pathogens Article Mosquitoes (Diptera: Culicidae) in the Dark—Highlighting the Importance of Genetically Identifying Mosquito Populations in Subterranean Environments of Central Europe Carina Zittra 1 , Simon Vitecek 2,3 , Joana Teixeira 4, Dieter Weber 4 , Bernadette Schindelegger 2, Francis Schaffner 5 and Alexander M. Weigand 4,* 1 Unit Limnology, Department of Functional and Evolutionary Ecology, University of Vienna, 1090 Vienna, Austria; [email protected] 2 WasserCluster Lunz—Biologische Station, 3293 Lunz am See, Austria; [email protected] (S.V.); [email protected] (B.S.) 3 Institute of Hydrobiology and Aquatic Ecosystem Management, University of Natural Resources and Life Sciences, Vienna, Gregor-Mendel-Strasse 33, 1180 Vienna, Austria 4 Zoology Department, Musée National d’Histoire Naturelle de Luxembourg (MNHNL), 2160 Luxembourg, Luxembourg; [email protected] (J.T.); [email protected] (D.W.) 5 Francis Schaffner Consultancy, 4125 Riehen, Switzerland; [email protected] * Correspondence: [email protected]; Tel.: +352-462-240-212 Abstract: The common house mosquito, Culex pipiens s. l. is part of the morphologically hardly or non-distinguishable Culex pipiens complex. Upcoming molecular methods allowed us to identify Citation: Zittra, C.; Vitecek, S.; members of mosquito populations that are characterized by differences in behavior, physiology, host Teixeira, J.; Weber, D.; Schindelegger, and habitat preferences and thereof resulting in varying pathogen load and vector potential to deal B.; Schaffner, F.; Weigand, A.M. with. In the last years, urban and surrounding periurban areas were of special interest due to the Mosquitoes (Diptera: Culicidae) in higher transmission risk of pathogens of medical and veterinary importance.
    [Show full text]
  • Culex Pipiens in Sweden Jenny C
    Hesson et al. Parasites & Vectors (2016) 9:632 DOI 10.1186/s13071-016-1925-3 LETTER TO THE EDITOR Open Access First report on human-biting Culex pipiens in Sweden Jenny C. Hesson1,2*, Martina Schäfer3 and Jan O. Lundström1,3 Abstract Culex mosquitoes are vectors of several bird-hosted arboviruses that cause outbreaks in Europe, such as Sindbis virus and West Nile virus. Recently, the human-biting form of Culex pipiens, Cx. pipiens biotype molestus, was found causing big nuisance in a housing cooperative in Gothenburg in southern Sweden, confirmed by molecular identification. This is the first report of human-biting Culex in Scandinavia, signalling increased risk of arbovirus infection in northern Europe. Keywords: Vector-borne infections, West Nile virus, Zoonoses, Mosquito vector, Arbovirus, Sindbis virus Letter to the Editor birds to humans, as they possess the vector competence of Mosquitoes of the genus Culex are the vectors of bird- Cx. pipiens biotype pipiens [5] but an opportunistic feed- hosted arboviruses that occasionally cause disease in ing behaviour [6]. humans, such as Sindbis virus (SINV) (Alphavirus) West The last countrywide mosquito survey recognised Nile virus (WNV) and Usutu virus (USUV) (Flavivirus), three Culex species as endemic to Sweden: the ornitho- all circulating in Europe. Seven potential vector species philic species Cx. torrentium, Cx. pipiens biotype pipiens are recognised within the genus Culex in Europe, most and Cx. territans that primarily feeds on ectothermic of which show a preference for biting birds (ornithophi- hosts [7]. Recently, an encounter with Cx. modestus that lic). One of the species, the northern house mosquito commonly bite man in central European countries has Cx.
    [Show full text]
  • Some Environmental Factors Influencing Rearing of the Spruce
    S AN ABSTRACT OF THE THESIS OF Gary Boyd Pitman for the M. S. in ENTOMOLOGY (Degree) (Major) Date thesis is presented y Title SOME ENVIRONMENTAL FACTORS INFLUENCING REARING OF THE SPRUCE BUDWORM, Choristoneura fumiferana (Clem.) (LEPIDOPTERA: TORTRICIDAE) UNDER LABORATORY CONDITIONS. Abstract approved , (Major Professor) The purpose of this study was to determine the effects of controlled environmental factors upon the development of the spruce budworm (Choristoneura fumiferana Clem.) and to utilize the information for im- proving mass rearing procedures. A standard and a green form of the bud - worm occurring in the Pacific Northwest were compared morphologically and as to their suitability for mass rearing. " An exploratory study demonstrated that both forms of the budworm could be reared in quantity in the laboratory under conditions outlined by Stehr, but that greater survival and efficiency of production would be needed for mass rearing purposes. Further experimentation revealed that, by manipulating environmental factors during the rearing process, the number of budworm generations could be increased from one that occurs normally to nearly three per year. For the standard form of the budworm, procedures were developed for in- creasing laboratory stock twelvefold per generation. Productivity of the green form was much less, indicating that the standard form may be better suited for laboratory rearing in quantity. Recommended rearing procedures consist of the following steps. Egg masses should be incubated at temperatures between 70 and 75 °F and a relative humidity near 77 percent. Under these conditions, embryo matur- ation and hibernacula site selection require approximately 8 to 9 days. The larvae should be left at incubation conditions for no longer than three weeks.
    [Show full text]
  • Our Legacy of Caring, Scholarship, and Scientific Discovery
    Our Legacy of Caring, Scholarship, and Scientific Discovery Duke Lemur Center EST. 1966, DUKE UNIVERSITY The Duke Lemur Center An extraordinary place exists in the heart of Duke Forest: an 80-acre campus of buildings and forested animal enclosures bustling with students, scientists, and visitors from around the world. They are drawn to this place to see, learn about, and explore the animals that call this place home: a colony of more than 200 of the most endangered mammals on Earth—lemurs. A world leader in the study, care, and protection of lemurs, the Duke Lemur Center (DLC) was established in 1966 on the campus of Duke University in Durham, NC. For over 50 years, the DLC has brought together scientists, conservation biologists, and educators to understand and protect these extraordinary primates and make new and exciting discoveries through interdisciplinary non-invasive research. The DLC works tirelessly not just in Durham but also in in Madagascar, the only place on Earth where lemurs exist in the wild. We’re proud to work with the organizations and people of Madagascar to create opportunities for positive change, and to play a leading role in preventing the island’s legendary population of endemic and endangered national treasures from being lost forever. “To look at the Duke Lemur Center today, you would never know it was once an unknown part of the Duke University campus. Today it’s a thriving hub of learning where Duke students and alumni, scientists, and animal lovers of all ages from around the world explore the importance of lemurs, scientific discovery, and conservation.
    [Show full text]
  • Reproductionreview
    REPRODUCTIONREVIEW Focus on Implantation Embryonic diapause and its regulation Flavia L Lopes, Joe¨lle A Desmarais and Bruce D Murphy Centre de Recherche en Reproduction Animale, Faculte´ de Me´decine Ve´te´rinaire, Universite´ de Montre´al, 3200 rue Sicotte, St-Hyacinthe, Quebec, Canada J2S7C6 Correspondence should be addressed to B D Murphy; Email: [email protected] Abstract Embryonic diapause, a condition of temporary suspension of development of the mammalian embryo, occurs due to suppres- sion of cell proliferation at the blastocyst stage. It is an evolutionary strategy to ensure the survival of neonates. Obligate dia- pause occurs in every gestation of some species, while facultative diapause ensues in others, associated with metabolic stress, usually lactation. The onset, maintenance and escape from diapause are regulated by cascades of environmental, hypophyseal, ovarian and uterine mechanisms that vary among species and between the obligate and facultative condition. In the best- known models, the rodents, the uterine environment maintains the embryo in diapause, while estrogens, in combination with growth factors, reinitiate development. Mitotic arrest in the mammalian embryo occurs at the G0 or G1 phase of the cell cycle, and may be due to expression of a specific cell cycle inhibitor. Regulation of proliferation in non- mammalian models of diapause provide clues to orthologous genes whose expression may regulate the reprise of proliferation in the mammalian context. Reproduction (2004) 128 669–678 Introduction recently been discussed in depth (Dey et al. 2004). In this presentation we address the characteristics of the embryo Embryonic diapause, also known as discontinuous devel- in diapause and focus on the mechanisms of regulation of opment or, in mammals, delayed implantation, is among this phenomenon, including the environmental and meta- the evolutionary strategies that ensure successful repro- bolic stimuli that induce and terminate this condition, the duction.
    [Show full text]
  • (Diptera: Culicidae) in Fianl›Urfa Province, Turkey
    TurkJZool 30(2006)383-392 ©TÜB‹TAK SeasonalFrequencyandRelativeDensityofLarvalPopulationsof MosquitoSpecies(Diptera:Culicidae)infianl›urfaProvince,Turkey* FatihMehmetfi‹MfiEK AdnanMenderesUniversity,FacultyofArtsandScience,DepartmentofBiology,EcologySection,09010Ayd›n-TURKEY Received:27.09.2005 Abstract: ThisresearchwasconductedbetweenJune2000andAugust2002in2regionsoffianl›urfa:one(IR)wheretherewas substantialirrigatedagricultureduetotheSoutheasternAnatoliaProjectandanother(MR)whereahighnumberofmalariacase s weredeterminedeveryyear.Tenspecies,namely Anopheles(Anopheles)claviger Meigen,1804,An.(Anopheles)sacharovi Favre, 1903,An.(Cellia)superpictus Grassi,1899, Culex(Neoculex) martinii Medschid,1930, Cx.(Culex)pipiens Linnaeus,1758, Cx. (Neoculex)territans Walker,1856, Cx.(Culex)theileri Theobald,1903, Culiseta(Allotheobaldia)longiareolata Macquart,1938, Ochlerotatus(Ochlerotatus)caspius Pallas,1771andUranotaenia(Pseudoficalbia)unguiculata Edwards,1903,wererecordedinthis study,andseasonalfrequenciesandrelativedensitiesoflarvalpopulationsweredeterminedseparatelyforeachregion.Based on thefrequencies,relativedensitiesandvectorialsignificanceofspeciesfoundinthisstudy,Culexpipiens,Cx.theileri andOchlerotatus caspius inIRandAnophelesclaviger,An.sacharovi,andAn.superpictus inMRwereofhighersignificance. KeyWords: Mosquitoes,larvalpopulation,frequency,relativedensity,malaria,fianl›urfa fianl›urfa‹li'ndeSivrisinekTürlerinin(Diptera:Culicidae) LarvaPopulasyonlar›n›nMevsimselS›kl›¤›veNisbiYo¤unlu¤u Özet: Buaraflt›rma,fianl›urfa‹li'nin,Güneydo¤uAnadoluProjesikapsam›ndasulutar›muygulamalar›n›nyap›ld›¤›bölgesi(IR)ileher
    [Show full text]
  • A Two-Year Survey on Mosquitoes of Lebanon Knio K.M.*, Markarian N.*, Kassis A.* & Nuwayri-Salti N.**
    Article available at http://www.parasite-journal.org or http://dx.doi.org/10.1051/parasite/2005123229 A TWO-YEAR SURVEY ON MOSQUITOES OF LEBANON KNIO K.M.*, MARKARIAN N.*, KASSIS A.* & NUWAYRI-SALTI N.** Summary: Résumé : LES MOUSTIQUES DU LIBAN : RÉSULTATS DE DEUX ANS DE RÉCOLTES A total of 6,500 mosquitoes were identified during a two-year survey (1999-2001) in Lebanon, and these belonged to twelve Au cours d’une période d’observation de deux ans (1999-2001), species: Culex pipiens, Cx. laticinctus, Cx. mimeticus, 6500 moustiques ont été identifiés au Liban et répartis en Cx. hortensis, Cx. judaicus, Aedes aegypti, Ae. cretinus, 12 espèces : Culex pipiens, Cx. laticinctus, Cx. mimeticus, Ochlerotatus caspius, Oc. geniculatus, Oc. pulchritarsis, Culiseta Cx. hortensis, Cx. judaicus, Aedes aegypti, Ae. cretinus, longiareolata and Anopheles claviger. Culex pipiens was the most Ochlerotatus caspius, Oc. geniculatus, Oc. pulchritarsis, Culiseta predominant species in Lebanon, collected indoors and outdoors. longiareolata and Anopheles claviger. Culex pipiens, l’espèce It was continuously abundant and active throughout the year. prédominante, a été collectée à l’extérieur et à l’intérieur. Elle a Culex judaicus was a small and rare mosquito and it is reported été trouvée abondante et active tout au long de l’année. Culex to occur for the first time in Lebanon. On the coastal areas, judaicus, espèce petite et rare, a été observée et identifiée pour Ochlerotatus caspius was very common, and proved to be a la première fois au Liban. Dans les zones côtières, il s’est avéré complex of species as two forms were detected.
    [Show full text]
  • Introduction to Pregnancy in Waiting: Embryonic Diapause in Mammals Proceedings of the Third International Symposium on Embryonic Diapause
    Proceedings of III International Symposium on Embryonic Diapause DOI: 10.1530/biosciprocs.10.001 Introduction to Pregnancy in Waiting: Embryonic Diapause in Mammals Proceedings of the Third International Symposium on Embryonic Diapause BD Murphy1, K Jewgenow2, MB Renfree3, SE Ulbrich4 1Centre de recherche en reproduction et fertilité, Université de Montréal, Canada 2Leibniz-Institute for Zoo and Wildlife Research, Berlin, Germany 3School of BioSciences, University of Melbourne, Australia 4Institute of Agricultural Sciences, ETH Zurich, Switzerland The capacity of the mammalian embryo to arrest development during early gestation is a topic that has fascinated biologists for over 150 years. The first known observation of this phenomenon was in a ruminant, the roe deer (Capreolus capreolus) in 1854, later confirmed in a number of studies in the last century [1]. The phenomenon, now known as embryonic diapause, was then found to be present in a wide range of species and across multiple taxa. Since that time, its biological mystery has attracted studies by scientists from around the globe. The First International Symposium on the topic of embryonic diapause in mammals was held in 1963 at Rice University, Houston, Texas. It resulted in a proceedings volume entitled “Delayed Implantation”, edited by A.C. Enders [2]. The symposium was distinguished by the novel recognition of that era that a wide range of species had been identified with embryonic diapause, including rodents, marsupials and carnivores. The emerging technology of the time, particularly structural approaches, permitted new understanding of the events of diapause and embryo reactivation. The newest methods provided key data on the temporal window of implantation in rodents, introduced new physiological approaches, and illustrated some of the first transmission electron microscope investigations of the blastocyst.
    [Show full text]
  • Embryonic Diapause in Mammals and Dormancy in Embryonic Stem Cells with the European Roe Deer As Experimental Model
    CSIRO PUBLISHING Reproduction, Fertility and Development, 2021, 33, 76–81 https://doi.org/10.1071/RD20256 Embryonic diapause in mammals and dormancy in embryonic stem cells with the European roe deer as experimental model Vera A. van der WeijdenA,*, Anna B. Ru¨eggA,*, Sandra M. Bernal-UlloaA and Susanne E. UlbrichA,B AETH Zurich, Animal Physiology, Institute of Agricultural Sciences, Universitaetstrasse 2, 8092 Zurich, Switzerland. BCorresponding author. Email: [email protected] Abstract. In species displaying embryonic diapause, the developmental pace of the embryo is either temporarily and reversibly halted or largely reduced. Only limited knowledge on its regulation and the inhibition of cell proliferation extending pluripotency is available. In contrast with embryos from other diapausing species that reversibly halt during diapause, embryos of the roe deer Capreolus capreolus slowly proliferate over a period of 4–5 months to reach a diameter of approximately 4 mm before elongation. The diapausing roe deer embryos present an interesting model species for research on preimplantation developmental progression. Based on our and other research, we summarise the available knowledge and indicate that the use of embryonic stem cells (ESCs) would help to increase our understanding of embryonic diapause. We report on known molecular mechanisms regulating embryonic diapause, as well as cellular dormancy of pluripotent cells. Further, we address the promising application of ESCs to study embryonic diapause, and highlight the current knowledge on the cellular microenvironment regulating embryonic diapause and cellular dormancy. Keywords: dormancy, embryonic diapause, embryonic stem cells, European roe deer Capreolus capreolus. Published online 8 January 2021 Embryonic diapause conditions. The roe deer is the only known ungulate exhibiting The time between fertilisation and embryo implantation varies embryonic diapause.
    [Show full text]