51
|
Rafikov M, Bevilacqua L, Wyse APP. Optimal control strategy of malaria vector using genetically modified mosquitoes. J Theor Biol 2008; 258:418-25. [PMID: 18761018 DOI: 10.1016/j.jtbi.2008.08.006] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2008] [Revised: 07/19/2008] [Accepted: 08/07/2008] [Indexed: 11/25/2022]
Abstract
The development of transgenic mosquitoes that are resistant to diseases may provide a new and effective weapon of diseases control. Such an approach relies on transgenic mosquitoes being able to survive and compete with wild-type populations. These transgenic mosquitoes carry a specific code that inhibits the plasmodium evolution in its organism. It is said that this characteristic is hereditary and consequently the disease fades away after some time. Once transgenic mosquitoes are released, interactions between the two populations and inter-specific mating between the two types of mosquitoes take place. We present a mathematical model that considers the generation overlapping and variable environment factors. Based on this continuous model, the malaria vector control is formulated and solved as an optimal control problem, indicating how genetically modified mosquitoes should be introduced in the environment. Numerical simulations show the effectiveness of the proposed control.
Collapse
Affiliation(s)
- M Rafikov
- UFABC and UNIJUI, Rua Santa Adélia, 166, Bairo Bangu, 09210-170 Santo André, SP, Brazil.
| | | | | |
Collapse
|
52
|
Yakob L, Alphey L, Bonsall MB. Aedes aegypticontrol: the concomitant role of competition, space and transgenic technologies. J Appl Ecol 2008. [DOI: 10.1111/j.1365-2664.2008.01498.x] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
|
53
|
|
54
|
Li J. Differential equations models for interacting wild and transgenic mosquito populations. JOURNAL OF BIOLOGICAL DYNAMICS 2008; 2:241-258. [PMID: 22876868 DOI: 10.1080/17513750701779633] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
We formulate and study continuous-time models, based on systems of ordinary differential equations, for interacting wild and transgenic mosquito populations. We assume that the mosquito mating rate is either constant, proportional to total mosquito population size, or has a Holling-II-type functional form. The focus is on the model with the Holling-II-type functional mating rate that incorporates Allee effects, in order to account for mating difficulty when the size of the total mosquito populations is small. We investigate the existence and stability of both boundary and positive equilibria. We show that the Holling-II-type model is the more realistic and, by means of numerical simulations, that it exhibits richer dynamics.
Collapse
Affiliation(s)
- Jia Li
- Department of Mathematical Sciences, University of Alabama in Huntsville, Huntsville, AL, USA.
| |
Collapse
|
55
|
Applications of mosquito ecology for successful insect transgenesis-based disease prevention programs. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2008. [PMID: 18510022 DOI: 10.1007/978-0-387-78225-6_13] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register]
|
56
|
Yoshida S, Shimada Y, Kondoh D, Kouzuma Y, Ghosh AK, Jacobs-Lorena M, Sinden RE. Hemolytic C-type lectin CEL-III from sea cucumber expressed in transgenic mosquitoes impairs malaria parasite development. PLoS Pathog 2008; 3:e192. [PMID: 18159942 PMCID: PMC2151087 DOI: 10.1371/journal.ppat.0030192] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2007] [Accepted: 10/30/2007] [Indexed: 12/14/2022] Open
Abstract
The midgut environment of anopheline mosquitoes plays an important role in the development of the malaria parasite. Using genetic manipulation of anopheline mosquitoes to change the environment in the mosquito midgut may inhibit development of the malaria parasite, thus blocking malaria transmission. Here we generate transgenic Anopheles stephensi mosquitoes that express the C-type lectin CEL-III from the sea cucumber, Cucumaria echinata, in a midgut-specific manner. CEL-III has strong and rapid hemolytic activity toward human and rat erythrocytes in the presence of serum. Importantly, CEL-III binds to ookinetes, leading to strong inhibition of ookinete formation in vitro with an IC50 of 15 nM. Thus, CEL-III exhibits not only hemolytic activity but also cytotoxicity toward ookinetes. In these transgenic mosquitoes, sporogonic development of Plasmodium berghei is severely impaired. Moderate, but significant inhibition was found against Plasmodium falciparum. To our knowledge, this is the first demonstration of stably engineered anophelines that affect the Plasmodium transmission dynamics of human malaria. Although our laboratory-based research does not have immediate applications to block natural malaria transmission, these findings have significant implications for the generation of refractory mosquitoes to all species of human Plasmodium and elucidation of mosquito–parasite interactions. Malaria is arguably the most important vector-borne disease worldwide, affecting 300 million people and killing 1–2 million people every year. The lack of an effective vaccine and the emergence of the parasites' resistance to many existing anti-malarial drugs have aggravated the situation. Clearly, development of novel strategies for control of the disease is urgently needed. Mosquitoes are obligatory vectors for the disease and inhibition of parasite development in the mosquito has considerable promise as a new approach in the fight against malaria. Based on recent advances in the genetic engineering of mosquitoes, the concept of generating genetically modified (GM) mosquitoes that hinder transmission by either killing or interfering with parasite development is a potential means of controlling the disease. To generate these GM mosquitoes, the authors focused on a unique lectin isolated from the sea cucumber, which has both hemolytic and cytotoxic activities, as an anti-parasite effector molecule. A transgenic mosquito expressing the lectin effectively caused erythrocyte lysis in the midgut after ingestion of an infectious blood meal and severely impaired parasite development. This laboratory-acquired finding may provide significant implications for future malaria control using GM mosquitoes refractory to the parasites.
Collapse
Affiliation(s)
- Shigeto Yoshida
- Division of Medical Zoology, Department of Infection and Immunity, Jichi Medical University, Tochigi, Japan.
| | | | | | | | | | | | | |
Collapse
|
57
|
Rodrigues FG, Santos MN, de Carvalho TXT, Rocha BC, Riehle MA, Pimenta PFP, Abraham EG, Jacobs-Lorena M, Alves de Brito CF, Moreira LA. Expression of a mutated phospholipase A2 in transgenic Aedes fluviatilis mosquitoes impacts Plasmodium gallinaceum development. INSECT MOLECULAR BIOLOGY 2008; 17:175-83. [PMID: 18353106 PMCID: PMC4137777 DOI: 10.1111/j.1365-2583.2008.00791.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The genetic manipulation of mosquito vectors is an alternative strategy in the fight against malaria. It was previously shown that bee venom phospholipase A2 (PLA2) inhibits ookinete invasion of the mosquito midgut although mosquito fitness was reduced. To maintain the PLA2 blocking ability without compromising mosquito biology, we mutated the protein-coding sequence to inactivate the enzyme while maintaining the protein's structure. DNA encoding the mutated PLA2 (mPLA2) was placed downstream of a mosquito midgut-specific promoter (Anopheles gambiae peritrophin protein 1 promoter, AgPer1) and this construct used to transform Aedes fluviatilis mosquitoes. Four different transgenic lines were obtained and characterized and all lines significantly inhibited Plasmodium gallinaceum oocyst development (up to 68% fewer oocysts). No fitness cost was observed when this mosquito species expressed the mPLA2.
Collapse
Affiliation(s)
- F G Rodrigues
- Laboratório de Malária, Instituto René Rachou, Fundação Oswaldo Cruz, Belo Horizonte-MG, Brazil
| | | | | | | | | | | | | | | | | | | |
Collapse
|
58
|
Li C, Marrelli MT, Yan G, Jacobs-Lorena M. Fitness of transgenic Anopheles stephensi mosquitoes expressing the SM1 peptide under the control of a vitellogenin promoter. J Hered 2008; 99:275-82. [PMID: 18334506 DOI: 10.1093/jhered/esn004] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
Abstract
Three transgenic Anopheles stephensi lines were established that strongly inhibit transmission of the mouse malaria parasite Plasmodium berghei. Fitness of the transgenic mosquitoes was assessed based on life table analysis and competition experiments between transgenic and wild-type mosquitoes. Life table analysis indicated low fitness load for the 2 single-insertion transgenic mosquito lines VD35 and VD26 and no load for the double-insertion transgenic mosquito line VD9. However, in cage experiments, where each of the 3 homozygous transgenic mosquitoes was mixed with nontransgenic mosquitoes, transgene frequency of all 3 lines decreased with time. Further experiments suggested that reduction of transgene frequency is a consequence of reduced mating success, reduced reproductive capacity, and/or insertional mutagenesis, rather than expression of the transgene itself. Thus, for transgenic mosquitoes released in the field to be effective in reducing malaria transmission, a driving mechanism will be required.
Collapse
Affiliation(s)
- Chaoyang Li
- Johns Hopkins University, Bloomberg School of Public Health, Department of Molecular Microbiology and Immunology and Malaria Research Institute, 615 North Wolfe Street, Baltimore MD 21205, USA
| | | | | | | |
Collapse
|
59
|
Abstract
Vector-borne diseases such as malaria and dengue fever continue to be a major health concern through much of the world. The emergence of chloroquine-resistant strains of malaria and insecticide-resistant mosquitoes emphasize the need for novel methods of disease control. Recently, there has been much interest in the use of transposable elements to drive resistance genes into vector populations as a means of disease control. One concern that must be addressed before a release is performed is the potential loss of linkage between a transposable element and a resistance gene. Transposable elements such as P and hobo have been shown to produce internal deletion derivatives at a significant rate, and there is concern that a similar process could lead to loss of the resistance gene from the drive system following a transgenic release. Additionally, transposable elements such as Himar1 have been shown to transpose significantly more frequently when free of exogenous DNA. Here, we show that any transposon-mediated gene drive strategy must have an exceptionally low rate of dissociation if it is to be effective. Additionally, the resistance gene must confer a large selective advantage to the vector to surmount the effects of a moderate dissociation rate and transpositional handicap.
Collapse
|
60
|
Using evolutionary costs to enhance the efficacy of malaria control via genetically manipulated mosquitoes. Parasitology 2008; 135:1489-96. [PMID: 18215334 DOI: 10.1017/s0031182007000261] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
An earlier mathematical model exploring the use of genetically manipulated mosquitoes for malaria control suggested that the prevalence of malaria is reduced significantly only if almost all mosquitoes become completely resistant to malaria. Central to the model was the 'cost of resistance': the reduction of a resistant mosquito's evolutionary fitness in comparison with a sensitive one's. Here, we consider the possibility of obtaining more optimistic outcomes by taking into account the epidemiological (in addition to the evolutionary) consequences of a cost of resistance that decreases the life-span of adult mosquitoes (the most relevant parameter for the parasite's epidemiology). There are two main results. First, if despite its cost, resistance is fixed in the population, increasing the cost of resistance decreases the intensity of transmission. However, this epidemiological effect is weak if resistance is effective enough to be considered relevant for control. Second, if the cost of resistance prevents its fixation, increasing it intensifies transmission. Thus, the epidemiological effect of the cost of resistance cannot compensate for the lower frequency of resistant mosquitoes in the population. Overall, our conclusion remains pessimistic: so that genetic manipulation can become a promising method of malaria control, we need techniques that enable almost all mosquitoes to be almost completely resistant to infection.
Collapse
|
61
|
Sperança MA, Capurro ML. Perspectives in the control of infectious diseases by transgenic mosquitoes in the post-genomic era--a review. Mem Inst Oswaldo Cruz 2008; 102:425-33. [PMID: 17612761 DOI: 10.1590/s0074-02762007005000054] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2006] [Accepted: 04/10/2007] [Indexed: 12/14/2022] Open
Abstract
Arthropod-borne diseases caused by a variety of microorganisms such as dengue virus and malaria parasites afflict billions of people worldwide imposing major economic and social burdens. Despite many efforts, vaccines against diseases transmitted by mosquitoes, with the exception of yellow fever, are not available. Control of such infectious pathogens is mainly performed by vector management and treatment of affected individuals with drugs. However, the numbers of insecticide-resistant insects and drug-resistant parasites are increasing. Therefore, inspired in recent years by a lot of new data produced by genomics and post-genomics research, several scientific groups have been working on different strategies to control infectious arthropod-borne diseases. This review focuses on recent advances and perspectives towards construction of transgenic mosquitoes refractory to malaria parasites and dengue virus transmission.
Collapse
|
62
|
Abstract
Research on gene expression in mosquitoes is motivated by both basic and applied interests. Studies of genes involved in hematophagy, reproduction, olfaction, and immune responses reveal an exquisite confluence of biological adaptations that result in these highly-successful life forms. The requirement of female mosquitoes for a bloodmeal for propagation has been exploited by a wide diversity of viral, protozoan and metazoan pathogens as part of their life cycles. Identifying genes involved in host-seeking, blood feeding and digestion, reproduction, insecticide resistance and susceptibility/refractoriness to pathogen development is expected to provide the bases for the development of novel methods to control mosquito-borne diseases. Advances in mosquito transgenesis technologies, the availability of whole genome sequence information, mass sequencing and analyses of transcriptomes and RNAi techniques will assist development of these tools as well as deepen the understanding of the underlying genetic components for biological phenomena characteristic of these insect species.
Collapse
Affiliation(s)
- Xiao-Guang Chen
- Department of Parasitology, School of Public Health and Tropical Medicine, Southern Medical University, Guang Zhou, GD 510515, People's Republic of China
| | | | | |
Collapse
|
63
|
Lambrechts L, Koella JC, Boëte C. Can transgenic mosquitoes afford the fitness cost? Trends Parasitol 2007; 24:4-7. [PMID: 18164248 DOI: 10.1016/j.pt.2007.09.009] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2007] [Revised: 09/20/2007] [Accepted: 09/20/2007] [Indexed: 11/18/2022]
Abstract
In a recent study, SM1-transgenic Anopheles stephensi, which are resistant partially to Plasmodium berghei, had higher fitness than non-transgenic mosquitoes when they were maintained on Plasmodium-infected blood. This result should be interpreted cautiously with respect to malaria control using transgenic mosquitoes because, despite the evolutionary advantage conferred by the transgene, a concomitant cost prevents it from invading the entire population. Indeed, for the spread of a resistance transgene in a natural situation, the transgene's fitness cost and the efficacy of the gene drive will be more crucial than any evolutionary advantage.
Collapse
Affiliation(s)
- Louis Lambrechts
- Department of Entomology, University of California, One Shields Avenue, Davis, CA 95616, USA
| | | | | |
Collapse
|
64
|
Matthews SD, Meehan LJ, Onyabe DY, Vineis J, Nock I, Ndams I, Conn JE. Evidence for late Pleistocene population expansion of the malarial mosquitoes, Anopheles arabiensis and Anopheles gambiae in Nigeria. MEDICAL AND VETERINARY ENTOMOLOGY 2007; 21:358-369. [PMID: 18092974 DOI: 10.1111/j.1365-2915.2007.00703.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Anopheles gambiae Giles s.s. and Anopheles arabiensis Patton (Diptera: Culicidae) are major vectors of malaria in Nigeria. We used 1115 bp of the mitochondrial COI gene to assess their population genetic structures based on samples from across Nigeria (n = 199). The mtDNA neighbour-joining tree, based on F(ST) estimates, separated An. gambiae M and S forms, except that samples of An. gambiae M from Calabar clustered with all the An. gambiae S form. Anopheles arabiensis and An. gambiae could be combined into a single star-shaped, parsimonious haplotype network, and shared three haplotypes. Haplotype diversity values were high in An. arabiensis and An. gambiae S, and intermediate in An. gambiae M; all nucleotide diversities were relatively low. Taken together, patterns of haplotype diversity, the star-like genealogy of haplotypes, five of seven significant neutrality tests, and the violation of the isolation-by-distance model indicate population expansion in An. arabiensis and An. gambiae S, but the signal was weak in An. gambiae M. Selection is supported as an important factor shaping genetic structure in An. gambiae in Nigeria. There were two geographical subdivisions in An. arabiensis: one included all southern localities and all but two central localities; the other included all northern and two central localities. Re-analysing an earlier microsatellite dataset of An. arabiensis using a Bayesian method determined that there were two distinctive clusters, northern and southern, that were fairly congruent with the mtDNA subdivisions. There was a trend towards decreasing genetic diversity in An. arabiensis from the northern savannah to the southern rainforest that corroborated previous data from microsatellites and polytene chromosomes.
Collapse
Affiliation(s)
- S D Matthews
- Department of Biomedical Sciences, School of Public Health, University at Albany, State University of New York, New York, U.S.A
| | | | | | | | | | | | | |
Collapse
|
65
|
Abraham EG, Cha SJ, Jacobs-Lorena M. Towards the genetic control of insect vectors: An overview. ENTOMOLOGICAL RESEARCH 2007; 37:213-220. [PMID: 25530773 PMCID: PMC4268783 DOI: 10.1111/j.1748-5967.2007.00117.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Insects are responsible for the transmission of major infectious diseases. Recent advances in insect genomics and transformation technology provide new strategies for the control of insect borne pathogen transmission and insect pest management. One such strategy is the genetic modification of insects with genes that block pathogen development. Another is to suppress insect populations by releasing either sterile males or males carrying female-specific dominant lethal genes into the environment. Although significant progress has been made in the laboratory, further research is needed to extend these approaches to the field. These insect control strategies offer several advantages over conventional insecticide-based strategies. However, the release of genetically modified insects into the environment should proceed with great caution, after ensuring its safety, and acceptance by the target populations.
Collapse
Affiliation(s)
- Eappen G Abraham
- Department of Molecular Microbiology and Immunology, John Hopkins Bloomberg School of Public Health and Johns Hopkins Malaria Research Institute, Baltimore, Maryland, USA
| | - Sung-Jae Cha
- Department of Molecular Microbiology and Immunology, John Hopkins Bloomberg School of Public Health and Johns Hopkins Malaria Research Institute, Baltimore, Maryland, USA
| | - Marcelo Jacobs-Lorena
- Department of Molecular Microbiology and Immunology, John Hopkins Bloomberg School of Public Health and Johns Hopkins Malaria Research Institute, Baltimore, Maryland, USA
| |
Collapse
|
66
|
Huho BJ, Ng'habi KR, Killeen GF, Nkwengulila G, Knols BGJ, Ferguson HM. Nature beats nurture: a case study of the physiological fitness of free-living and laboratory-reared male Anopheles gambiae s.l. ACTA ACUST UNITED AC 2007; 210:2939-47. [PMID: 17690243 DOI: 10.1242/jeb.005033] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Laboratory experimentation forms the basis for most of our knowledge of the biology of many organisms, in particular insects. However, the accuracy with which laboratory-derived estimates of insect life history and behaviour can predict their fitness and population dynamics in the wild is rarely validated. Such comparison is especially important in cases where laboratory-derived information is used to formulate and implement strategies for the genetic control of insects in nature. We have conducted a comparative study of the reproductive potential and life history of male Anopheles gambiae Gilies sensu lato mosquitoes from both standardized laboratory conditions and from natural field settings. We measured three indirect indicators of male mosquito fitness: energetic reserves, body size and survival, in a bid to determine whether the demographics and energetic limitations of wild males can be correctly predicted from their laboratory counterparts. Crucially, the body size and lipid reserves of wild males were substantially greater than those reared under standard laboratory conditions. We caution that the energetic limitations of insects as identified in the laboratory may underestimate their resilience in the wild, and discuss the implications of this phenomenon with respect to vector-borne disease control programmes based on genetic control of mosquitoes.
Collapse
Affiliation(s)
- B J Huho
- Public Health Entomology Unit, Ifakara Health Research and Development Centre, PO Box 53, Off Mlabani Passage Ifakara, Tanzania.
| | | | | | | | | | | |
Collapse
|
67
|
Voordouw MJ, Koella JC. Genetic variation of male reproductive success in a laboratory population of Anopheles gambiae. Malar J 2007; 6:99. [PMID: 17663767 PMCID: PMC1971063 DOI: 10.1186/1475-2875-6-99] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2007] [Accepted: 07/30/2007] [Indexed: 12/16/2022] Open
Abstract
Background For Anopheline mosquitoes, the vectors of human malaria, genetic variation in male reproductive success can have important consequences for any control strategy based on the release of transgenic or sterile males. Methods A quantitative genetics approach was used to test whether there was a genetic component to variation in male reproductive success in a laboratory population of Anopheles gambiae. Swarms of full sibling brothers were mated with a fixed number of females and their reproductive success was measured as (1) proportion of ovipositing females, (2) proportion of ovipositing females that produced larvae, (3) proportion of females that produced larvae, (4) number of eggs laid per female, (5) number of larvae per ovipositing female and (6) number of larvae per female. Results The proportion of ovipositing females (trait 1) and the proportion of ovipositing females that produced larvae (trait 2) differed among full sib families, suggesting a genetic basis of mating success. In contrast, the other measures of male reproductive success showed little variation due to the full sib families, as their variation are probably mostly due to differences among females. While age at emergence and wing length of the males were also heritable, they were not associated with reproductive success. Larger females produced more eggs, but males did not prefer such partners. Conclusion The first study to quantify genetic variation for male reproductive success in A. gambiae found that while the initial stages of male reproduction (i.e. the proportion of ovipositing females and the proportion of ovipositing females that produced larvae) had a genetic basis, the overall reproductive success (i.e. the mean number of larvae per female) did not.
Collapse
Affiliation(s)
- Maarten J Voordouw
- Division of Biology, Imperial College of London, Silwood Park Campus, Buckhurst Road, Ascot, Berkshire, SL5 7PY, UK
- School of Life Sciences, Huxley Building, Keele University, Staffordshire, UK
| | - Jacob C Koella
- Division of Biology, Imperial College of London, Silwood Park Campus, Buckhurst Road, Ascot, Berkshire, SL5 7PY, UK
| |
Collapse
|
68
|
Lobo NF, Clayton JR, Fraser MJ, Kafatos FC, Collins FH. High efficiency germ-line transformation of mosquitoes. Nat Protoc 2007; 1:1312-7. [PMID: 17406416 DOI: 10.1038/nprot.2006.221] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The ability to manipulate the mosquito genome through germ-line transformation provides us with a powerful tool for investigating gene structure and function. It is also a valuable method for the development of novel approaches to combating the spread of mosquito-vectored diseases. To date, germ-line transformation has been demonstrated in several mosquito species. Transgenes are introduced into pre-blastocyst mosquito embryos using microinjection techniques that take a few hours, and progeny are screened for the presence of a marker gene. The microinjection protocol presented here can be applied to most mosquitoes and contains several improvements over other published methods that increase the survival of injected embryos and, therefore, the number of transformants. Transgenic lines can be established in approximately 1 month using this technique.
Collapse
Affiliation(s)
- Neil F Lobo
- Center for Global Health and Infectious Diseases, Department of Biological Sciences, University of Notre Dame, Notre Dame, IN 46556, USA
| | | | | | | | | |
Collapse
|
69
|
Atkinson MP, Su Z, Alphey N, Alphey LS, Coleman PG, Wein LM. Analyzing the control of mosquito-borne diseases by a dominant lethal genetic system. Proc Natl Acad Sci U S A 2007; 104:9540-5. [PMID: 17519336 PMCID: PMC1876161 DOI: 10.1073/pnas.0610685104] [Citation(s) in RCA: 101] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Motivated by the failure of current methods to control dengue fever, we formulate a mathematical model to assess the impact on the spread of a mosquito-borne viral disease of a strategy that releases adult male insects homozygous for a dominant, repressible, lethal genetic trait. A dynamic model for the female adult mosquito population, which incorporates the competition for female mating between released mosquitoes and wild mosquitoes, density-dependent competition during the larval stage, and realization of the lethal trait either before or after the larval stage, is embedded into a susceptible-exposed-infectious-susceptible human-vector epidemic model for the spread of the disease. For the special case in which the number of released mosquitoes is maintained in a fixed proportion to the number of adult female mosquitoes at each point in time, we derive mathematical formulas for the disease eradication condition and the approximate number of released mosquitoes necessary for eradication. Numerical results using data for dengue fever suggest that the proportional policy outperforms a release policy in which the released mosquito population is held constant, and that eradication in approximately 1 year is feasible for affected human populations on the order of 10(5) to 10(6), although the logistical considerations are daunting. We also construct a policy that achieves an exponential decay in the female mosquito population; this policy releases approximately the same number of mosquitoes as the proportional policy but achieves eradication nearly twice as fast.
Collapse
Affiliation(s)
| | - Zheng Su
- Institute for Computational and Mathematical Engineering and
| | - Nina Alphey
- Department of Zoology, University of Oxford, South Parks Road, Oxford OX1 3PS, United Kingdom
- Oxitec, Limited, 71 Milton Park, Abingdon, Oxford OX14 4RX, United Kingdom; and
| | - Luke S. Alphey
- Department of Zoology, University of Oxford, South Parks Road, Oxford OX1 3PS, United Kingdom
- Oxitec, Limited, 71 Milton Park, Abingdon, Oxford OX14 4RX, United Kingdom; and
| | - Paul G. Coleman
- Oxitec, Limited, 71 Milton Park, Abingdon, Oxford OX14 4RX, United Kingdom; and
- Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, United Kingdom
| | - Lawrence M. Wein
- Graduate School of Business, Stanford University, Stanford, CA 94305
- To whom correspondence should be addressed. E-mail:
| |
Collapse
|
70
|
Late-acting dominant lethal genetic systems and mosquito control. BMC Biol 2007; 5:11. [PMID: 17374148 PMCID: PMC1865532 DOI: 10.1186/1741-7007-5-11] [Citation(s) in RCA: 252] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2007] [Accepted: 03/20/2007] [Indexed: 01/21/2023] Open
Abstract
BACKGROUND Reduction or elimination of vector populations will tend to reduce or eliminate transmission of vector-borne diseases. One potential method for environmentally-friendly, species-specific population control is the Sterile Insect Technique (SIT). SIT has not been widely used against insect disease vectors such as mosquitoes, in part because of various practical difficulties in rearing, sterilization and distribution. Additionally, vector populations with strong density-dependent effects will tend to be resistant to SIT-based control as the population-reducing effect of induced sterility will tend to be offset by reduced density-dependent mortality. RESULTS We investigated by mathematical modeling the effect of manipulating the stage of development at which death occurs (lethal phase) in an SIT program against a density-dependence-limited insect population. We found late-acting lethality to be considerably more effective than early-acting lethality. No such strains of a vector insect have been described, so as a proof-of-principle we constructed a strain of the principal vector of the dengue and yellow fever viruses, Aedes (Stegomyia) aegypti, with the necessary properties of dominant, repressible, highly penetrant, late-acting lethality. CONCLUSION Conventional SIT induces early-acting (embryonic) lethality, but genetic methods potentially allow the lethal phase to be tailored to the program. For insects with strong density-dependence, we show that lethality after the density-dependent phase would be a considerable improvement over conventional methods. For density-dependent parameters estimated from field data for Aedes aegypti, the critical release ratio for population elimination is modeled to be 27% to 540% greater for early-acting rather than late-acting lethality. Our success in developing a mosquito strain with the key features that the modeling indicated were desirable demonstrates the feasibility of this approach for improved SIT for disease control.
Collapse
|
71
|
Marrelli MT, Li C, Rasgon JL, Jacobs-Lorena M. Transgenic malaria-resistant mosquitoes have a fitness advantage when feeding on Plasmodium-infected blood. Proc Natl Acad Sci U S A 2007; 104:5580-3. [PMID: 17372227 PMCID: PMC1838510 DOI: 10.1073/pnas.0609809104] [Citation(s) in RCA: 90] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The introduction of genes that impair Plasmodium development into mosquito populations is a strategy being considered for malaria control. The effect of the transgene on mosquito fitness is a crucial parameter influencing the success of this approach. We have previously shown that anopheline mosquitoes expressing the SM1 peptide in the midgut lumen are impaired for transmission of Plasmodium berghei. Moreover, the transgenic mosquitoes had no noticeable fitness load compared with nontransgenic mosquitoes when fed on noninfected mice. Here we show that when fed on mice infected with P. berghei, these transgenic mosquitoes are more fit (higher fecundity and lower mortality) than sibling nontransgenic mosquitoes. In cage experiments, transgenic mosquitoes gradually replaced nontransgenics when mosquitoes were maintained on mice infected with gametocyte-producing parasites (strain ANKA 2.34) but not when maintained on mice infected with gametocyte-deficient parasites (strain ANKA 2.33). These findings suggest that when feeding on Plasmodium-infected blood, transgenic malaria-resistant mosquitoes have a selective advantage over nontransgenic mosquitoes. This fitness advantage has important implications for devising malaria control strategies by means of genetic modification of mosquitoes.
Collapse
Affiliation(s)
- Mauro T. Marrelli
- Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health and Malaria Research Institute, The Johns Hopkins University, 615 North Wolfe Street, Baltimore, MD 21205
| | - Chaoyang Li
- Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health and Malaria Research Institute, The Johns Hopkins University, 615 North Wolfe Street, Baltimore, MD 21205
| | - Jason L. Rasgon
- Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health and Malaria Research Institute, The Johns Hopkins University, 615 North Wolfe Street, Baltimore, MD 21205
| | - Marcelo Jacobs-Lorena
- Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health and Malaria Research Institute, The Johns Hopkins University, 615 North Wolfe Street, Baltimore, MD 21205
- To whom correspondence should be addressed. E-mail:
| |
Collapse
|
72
|
Linser PJ, Boudko DY, Corena MDP, Harvey WR, Seron TJ. The molecular genetics of larval mosquito biology: a path to new strategies for control. JOURNAL OF THE AMERICAN MOSQUITO CONTROL ASSOCIATION 2007; 23:283-93. [PMID: 17853613 DOI: 10.2987/8756-971x(2007)23[283:tmgolm]2.0.co;2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Affiliation(s)
- Paul J Linser
- The University of Florida Whitney Laboratory for Marine Bioscience, 9505 Ocean Shore Blvd., Saint Augustine, FL 32080-8610, USA
| | | | | | | | | |
Collapse
|
73
|
Abstract
The elegant mechanisms by which naturally occurring selfish genetic elements, such as transposable elements, meiotic drive genes, homing endonuclease genes and Wolbachia, spread at the expense of their hosts provide some of the most fascinating and remarkable subjects in evolutionary genetics. These elements also have enormous untapped potential to be used in the control of some of the world's most devastating diseases. Effective gene drive systems for spreading genes that can block the transmission of insect-borne pathogens are much needed. Here we explore the potential of natural gene drive systems and discuss the artificial constructs that could be envisaged for this purpose.
Collapse
Affiliation(s)
- Steven P Sinkins
- Department of Zoology, University of Oxford, Oxford OX1 3PS, UK.
| | | |
Collapse
|
74
|
Le Rouzic A, Capy P. Reversible introduction of transgenes in natural populations of insects. INSECT MOLECULAR BIOLOGY 2006; 15:227-34. [PMID: 16640733 DOI: 10.1111/j.1365-2583.2006.00631.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
The most serious challenge concerning genetically modified insects remains their invasion ability. Indeed, transgenic insects often show lower fitness than wild individuals, and the transgene does not seem able to spread through a natural population without a driving system. The use of remobilizable vectors, based on the invading properties of transposable elements, has been frequently suggested. Simulations show that this strategy can be efficient. Moreover, if the transgene is designed to use transposition machinery already present in the genome, the transgene invasion appears to be potentially reversible after a few hundred generations, leading to new experimental perspectives.
Collapse
Affiliation(s)
- A Le Rouzic
- Laboratoire Populations, Génétique, Evolution, CNRS, Gif sur Yvette, France
| | | |
Collapse
|
75
|
Marrelli MT, Moreira CK, Kelly D, Alphey L, Jacobs-Lorena M. Mosquito transgenesis: what is the fitness cost? Trends Parasitol 2006; 22:197-202. [PMID: 16564223 DOI: 10.1016/j.pt.2006.03.004] [Citation(s) in RCA: 110] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2005] [Revised: 01/18/2006] [Accepted: 03/08/2006] [Indexed: 12/14/2022]
Abstract
The generation of transgenic mosquitoes with a minimal fitness load is a prerequisite for the success of strategies for controlling mosquito-borne diseases using transgenic insects. It is important to assemble as much information as possible on this subject because realistic estimates of transgene fitness costs are essential for modeling and planning release strategies. Transgenic mosquitoes must have minimal fitness costs, because such costs would reduce the effectiveness of the genetic drive mechanisms that are used to introduce the transgenes into field mosquito populations. Several factors affect fitness of transgenic mosquitoes, including the potential negative effect of transgene products and insertional mutagenesis. Studies to assess fitness of transgenic mosquitoes in the field (as opposed to the laboratory) are still needed.
Collapse
Affiliation(s)
- Mauro T Marrelli
- Johns Hopkins University, Bloomberg School of Public Health Department of Molecular Microbiology and Immunology and Malaria Research Institute, 615 North Wolfe Street, Baltimore, MD 21205, USA
| | | | | | | | | |
Collapse
|
76
|
Zhong D, Temu EA, Guda T, Gouagna L, Menge D, Pai A, Githure J, Beier JC, Yan G. Dynamics of gene introgression in the African malaria vector Anopheles gambiae. Genetics 2006; 172:2359-65. [PMID: 16452145 PMCID: PMC1456378 DOI: 10.1534/genetics.105.050781] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Anopheles gambiae is a major malaria vector in Africa and a popular model species for a variety of ecological, evolutionary, and genetic studies on vector control. Genetic manipulation of mosquito vectorial capacity is a promising new weapon for the control of malaria. However, the release of exotic transgenic mosquitoes will bring in novel alleles in addition to the parasite-inhibiting genes, which may have unknown effects on the local population. Therefore, it is necessary to develop methodologies that can be used to evaluate the spread rate of introduced genes in A. gambiae. In this study, the effects and dynamics of genetic introgression between two geographically distinct A. gambiae populations from western Kenya (Mbita) and eastern Tanzania (Ifakara) were investigated with amplified fragment length polymorphisms (AFLPs) and microsatellite markers. Microsatellites and polymorphic cDNA markers revealed a large genetic differentiation between the two populations (average F(ST) = 0.093, P < 0.001). When the two strains were crossed in random mating between the two populations, significant differences in the rate of genetic introgression were found in the mixed populations. Allele frequencies of 18 AFLP markers (64.3%) for Mbita and of 26 markers (92.9%) for Ifakara varied significantly from F5 to F20. This study provides basic information on how a mosquito release program would alter the genetic makeup of natural populations, which is critical for pilot field testing and ecological risk evaluation of transgenic mosquitoes.
Collapse
Affiliation(s)
- Daibin Zhong
- Program in Public Health, College of Health Sciences, University of California, Irvine 92697, USA.
| | | | | | | | | | | | | | | | | |
Collapse
|
77
|
Magori K, Gould F. Genetically engineered underdominance for manipulation of pest populations: a deterministic model. Genetics 2006; 172:2613-20. [PMID: 16415364 PMCID: PMC1456375 DOI: 10.1534/genetics.105.051789] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
We theoretically investigate the potential for introgressing a desired engineered gene into a pest population by linking the desired gene to DNA constructs that exhibit underdominance properties. Our deterministic model includes two independently segregating engineered constructs that both carry a lethal gene, but suppress each other. Only genotypes containing both or neither construct are viable. Both constructs also carry the desired gene with an independent regulatory mechanism. We examine the minimal number of individuals of an engineered strain that must be released into a natural population to successfully introgress the desired gene. We compare results for strains carrying single and multiple insertions of the constructs. When there are no fitness costs associated with the inserted constructs (when the lethal sequences are not expressed), the number of individuals that must be released decreases as the number of insertions in the genome of the released strain increases. As fitness costs increase, the number of individuals that must be released increases at a greater rate for release strains with more insertions. Under specific conditions this results in the strain with only a single insertion of each construct being the most efficient for introgressing the desired gene. We discuss practical implications of our findings.
Collapse
Affiliation(s)
- Krisztian Magori
- Department of Entomology, North Carolina State University, Raleigh, North Carolina 27607, USA.
| | | |
Collapse
|
78
|
Ng'habi KR, John B, Nkwengulila G, Knols BGJ, Killeen GF, Ferguson HM. Effect of larval crowding on mating competitiveness of Anopheles gambiae mosquitoes. Malar J 2005; 4:49. [PMID: 16197541 PMCID: PMC1260028 DOI: 10.1186/1475-2875-4-49] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2005] [Accepted: 09/30/2005] [Indexed: 11/10/2022] Open
Abstract
Background The success of sterile or transgenic Anopheles for malaria control depends on their mating competitiveness within wild populations. Current evidence suggests that transgenic mosquitoes have reduced fitness. One means of compensating for this fitness deficit would be to identify environmental conditions that increase their mating competitiveness, and incorporate them into laboratory rearing regimes. Methods Anopheles gambiae larvae were allocated to three crowding treatments with the same food input per larva. Emerged males were competed against one another for access to females, and their corresponding longevity and energetic reserves measured. Results Males from the low-crowding treatment were much more likely to acquire the first mating. They won the first female approximately 11 times more often than those from the high-crowding treatment (Odds ratio = 11.17) and four times more often than those from the medium-crowding treatment (Odds ratio = 3.51). However, there was no overall difference in the total number of matings acquired by males from different treatments (p = 0.08). The survival of males from the low crowding treatment was lower than those from other treatments. The body size and teneral reserves of adult males did not differ between crowding treatments, but larger males were more likely to acquire mates than small individuals. Conclusion Larval crowding and body size have strong, independent effects on the mating competitiveness of adult male An. gambiae. Thus manipulation of larval crowding during mass rearing could provide a simple technique for boosting the competitiveness of sterile or transgenic male mosquitoes prior to release.
Collapse
Affiliation(s)
- Kija R Ng'habi
- Ifakara Health Research and Development Centre (IHRDC), P. O. Box 53, Ifakara, Tanzania
- University of Dar es Salaam, P. O. Box 35064 Dar es Salaam, Tanzania
| | - Bernadette John
- Ifakara Health Research and Development Centre (IHRDC), P. O. Box 53, Ifakara, Tanzania
- University of Dar es Salaam, P. O. Box 35064 Dar es Salaam, Tanzania
| | - Gamba Nkwengulila
- University of Dar es Salaam, P. O. Box 35064 Dar es Salaam, Tanzania
| | - Bart GJ Knols
- International Atomic Energy Agency (IAEA), Agency's Laboratories Seibersdorf, Seibersdorf A-2444, Austria
- Laboratory of Entomology. P.O. Box 8031, 6700 EH, Wageningen University, Wageningen, The Netherlands
| | - Gerry F Killeen
- Ifakara Health Research and Development Centre (IHRDC), P. O. Box 53, Ifakara, Tanzania
- Department of Public Health and Epidemiology, Swiss Tropical Institute, Basel, Switzerland
| | - Heather M Ferguson
- Ifakara Health Research and Development Centre (IHRDC), P. O. Box 53, Ifakara, Tanzania
- Laboratory of Entomology. P.O. Box 8031, 6700 EH, Wageningen University, Wageningen, The Netherlands
| |
Collapse
|
79
|
Menge DM, Guda T, Zhong D, Pai A, Zhou G, Beier JC, Gouagna L, Yan G. Fitness consequences of Anopheles gambiae population hybridization. Malar J 2005; 4:44. [PMID: 16174295 PMCID: PMC1242248 DOI: 10.1186/1475-2875-4-44] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2005] [Accepted: 09/20/2005] [Indexed: 12/02/2022] Open
Abstract
BACKGROUND The use of transgenic mosquitoes with parasite inhibiting genes has been proposed as an integral strategy to control malaria transmission. However, release of exotic transgenic mosquitoes will bring in novel alleles along with parasite-inhibiting genes that may have unknown effects on native populations. Thus it is necessary to study the effects and dynamics of fitness traits in native mosquito populations in response to the introduction of novel genes. This study was designed to evaluate the dynamics of fitness traits in a simulation of introduction of novel alleles under laboratory conditions using two strains of Anopheles gambiae: Mbita strain from western Kenya and Ifakara strain from Tanzania. METHODS The dynamics of fitness traits were evaluated under laboratory conditions using the two An. gambiae strains. These two geographically different strains were cross-bred and monitored for 20 generations to score fecundity, body size, blood-meal size, larval survival, and adult longevity, all of which are important determinants of the vector's potential in malaria transmission. Traits were analysed using pair-wise analysis of variance (ANOVA) for fecundity, body size, and blood-meal size while survival analysis was performed for larval survival and adult longevity. RESULTS Fecundity and body size were significantly higher in the progeny up to the 20th generation compared to founder strains. Adult longevity had a significantly higher mean up to the 10th generation and average blood-meal size was significantly larger up to the 5th generation, indicating that hybrids fitness is enhanced over that of the founder strains. CONCLUSION Hybridization of the two mosquito populations used in this study led to increased performance in the fitness traits studied. Given that the studied traits are important determinants of the vector's potential to transmit malaria, these results suggest the need to release genetically modified mosquitoes that have the same or very similar backgrounds to the native populations.
Collapse
Affiliation(s)
- David M Menge
- Department of Biological Sciences, State University of New York at Buffalo, Buffalo, NY 14260, USA
| | - Tom Guda
- Mbita Point Field and Training Station, International Center of Insect Physiology and Ecology, P.O. Box 30772, Nairobi, Kenya
| | - Daibin Zhong
- Department of Biological Sciences, State University of New York at Buffalo, Buffalo, NY 14260, USA
| | - Aditi Pai
- Department of Biological Sciences, State University of New York at Buffalo, Buffalo, NY 14260, USA
| | - Goufa Zhou
- Department of Biological Sciences, State University of New York at Buffalo, Buffalo, NY 14260, USA
| | - John C Beier
- Department of Epidemiology and Public Health, University of Miami, Miami, FL 33177, USA
| | - Louis Gouagna
- Mbita Point Field and Training Station, International Center of Insect Physiology and Ecology, P.O. Box 30772, Nairobi, Kenya
- Institut de Recherche pour le Développement (IRD) UR 016/ LIN, 911 avenue Agropolis, BP 64501 34394 Montpellier Cedex 5, France
| | - Guiyun Yan
- Department of Biological Sciences, State University of New York at Buffalo, Buffalo, NY 14260, USA
| |
Collapse
|
80
|
Abstract
As the malaria burden persists in most parts of the developing world, the concept of implementation of new strategies such as the use of genetically modified mosquitoes to control the disease continues to gain support. In Africa, which suffers most from malaria, mosquito vector populations are spread almost throughout the entire continent, and the parasite reservoir is big and continuously increasing. Moreover, malaria is transmitted by many species of anophelines with specific seasonal and geographical patterns. Therefore, a well designed, evolutionarily robust and publicly accepted plan aiming at population reduction or replacement is required. The task is twofold: to engineer mosquitoes with a genetic trait that confers resistance to malaria or causes population suppression; and, to drive the new trait through field populations. This review examines these two issues, and describes the groundwork that has been done towards understanding of the complex relation between the parasite and its vector.
Collapse
|
81
|
Abraham EG, Donnelly-Doman M, Fujioka H, Ghosh A, Moreira L, Jacobs-Lorena M. Driving midgut-specific expression and secretion of a foreign protein in transgenic mosquitoes with AgAper1 regulatory elements. INSECT MOLECULAR BIOLOGY 2005; 14:271-9. [PMID: 15926896 DOI: 10.1111/j.1365-2583.2004.00557.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
The Anopheles gambiae adult peritrophic matrix protein 1 (AgAper1) regulatory elements were used to drive the expression of phospholipase A2 (PLA2), a protein known to disrupt malaria parasite development in mosquitoes. These AgAper1 regulatory elements were sufficient to promote the accumulation of PLA2 in midgut epithelial cells before a blood meal and its release into the lumen upon blood ingestion. Plasmodium berghei oocyst formation was reduced by approximately 80% (74-91% range) in transgenic mosquitoes. Blood-seeking behaviour and survival of AgAper1-PLA2 transgenic mosquitoes were comparable to sibling wild-type mosquitoes, while fertility was substantially lower. Ultrastructural studies suggest that decreased fitness is a consequence of internal damage to midgut epithelial cells.
Collapse
Affiliation(s)
- E G Abraham
- Department of Molecular Microbiology and Immunology, John Hopkins Bloomberg School of Public Health, Malaria Research Institute, Baltimore, MD 21205, USA
| | | | | | | | | | | |
Collapse
|
82
|
Abstract
Population replacement strategies for controlling transmission of mosquito-borne diseases call for the introgression of antipathogen effector genes into vector populations. It is anticipated that these genes, if present at high enough frequencies, will impede transmission of the target pathogens and result in reduced human morbidity and mortality. Recent laboratory successes in the development of virus- and protozoan-resistant mosquito strains make urgent research of gene drive systems capable of moving effector genes into wild populations. A systematic approach to developing safe and effective gene drive systems that includes defining the requirements of the system, identifying naturally occurring or synthetic genetic mechanisms for gene spread upon which drive systems can be based and the successful adaptation of a mechanism to a drive system, should mitigate concerns about using genetically engineered mosquitoes for disease control.
Collapse
|
83
|
Li J. Simple mathematical models for interacting wild and transgenic mosquito populations. Math Biosci 2004; 189:39-59. [PMID: 15051413 DOI: 10.1016/j.mbs.2004.01.001] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2003] [Revised: 01/13/2004] [Accepted: 01/14/2004] [Indexed: 11/20/2022]
Abstract
Two discrete-time models for interacting populations of wild and genetically altered mosquito are presented, where the genetically altered mosquitoes are grouped into a single population without distinguishing their zygosity. The birth and death rates for both populations are density-dependent, and the mating rates between the mosquitoes are assumed to be either constant or proportional to the total populations for the two models, respectively. The existence and stability of the boundary and positive equilibria are investigated. In particular, it is shown that bifurcations from both boundary and positive equilibria can appear for the model with proportional mating rates. Stable equilibria, periodic-doubling bifurcations, aperiodic oscillations, and chaotic behavior are all illustrated by numerical simulations.
Collapse
Affiliation(s)
- Jia Li
- Department of Mathematical Sciences, University of Alabama in Huntsville, Huntsville, AL 35899, USA.
| |
Collapse
|