Displaying publications 1 - 20 of 41 in total

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  1. Macha NO, Komarasamy TV, Harun S, Adnan NAA, Hassan SS, Balasubramaniam VRMT
    Am J Trop Med Hyg, 2024 May 01;110(5):856-867.
    PMID: 38579704 DOI: 10.4269/ajtmh.23-0546
    Dengue fever (DF) is an endemic infectious tropical disease and is rapidly becoming a global problem. Dengue fever is caused by one of the four dengue virus (DENV) serotypes and is spread by the female Aedes mosquito. Clinical manifestations of DF may range from asymptomatic to life-threatening severe illness with conditions of hemorrhagic fever and shock. Early and precise diagnosis is vital to avoid mortality from DF. A different approach is required to combat DF because of the challenges with the vaccines currently available, which are nonspecific; each is capable of causing cross-reaction and disease-enhancing antibody responses against the residual serotypes. MicroRNAs (miRNAs) are known to be implicated in DENV infection and are postulated to be involved in most of the host responses. Thus, they might be a suitable target for new strategies against the disease. The involvement of miRNAs in cellular activities and pathways during viral infections has been explored under numerous conditions. Interestingly, miRNAs have also been shown to be involved in viral replication. In this review, we summarize the role of known miRNAs, specifically the role of miRNA Let-7c (miR-Let-7c), miR-133a, miR-30e, and miR-146a, in the regulation of DENV replication and their possible effects on the initial immune reaction.
    Matched MeSH terms: Aedes/genetics
  2. Black WC, Hawley WA, Rai KS, Craig GB
    Heredity (Edinb), 1988 Dec;61 ( Pt 3):439-46.
    PMID: 3230033
    The mosquito, Aedes albopictus, has recently become established in a number of cities throughout the United States. An initial survey of allozyme and genotypic frequencies in U.S. populations (Black et al., 1988) revealed an extensive amount of local differentiation of populations and suggested that much genetic drift may have accompanied colonization. A study of gene flow was initiated in native habitats of Ae. albopictus in Malaysia to determine if the result observed in the U.S. was a consequence of colonization or simply followed the natural breeding structure of the species. Allelic and genotypic frequencies were monitored at ten enzymatic loci in 11 populations from peninsular Malaysia and Borneo. Multiple populations were sampled within the districts of Kuala Lumpur and Kuala Trengganu. Peninsular Malaysian and Borneo populations were strongly genetically differentiated. Allele frequencies were significantly different among and within districts in both regions. Variance in allele frequencies among all collections was partitioned into the variance among regions, districts within regions and collections within districts. Almost all of the variance within regions was attributable to local differentiation suggesting that genetic drift is an important component of the natural breeding structure of this species. This indicates that the large amounts of local differentiation found in U.S. populations was not a consequence of recent colonization.
    Matched MeSH terms: Aedes/genetics
  3. Rosilawati R, Nabila R, Siti Futri Farahininajua F, Nazni WA, Lee HL
    Trop Biomed, 2019 Dec 01;36(4):855-865.
    PMID: 33597458
    The mechanism of insecticide resistance is traditionally attributed to detoxification enzymes, target site alteration, decreased penetration of insecticides and behavioural resistance. Other form of mechanisms, such as the role of protein(s) in resistance is unknown. In the present study, the protein profiling of both IMR-PSS strain (permethrin-selected) and IMR-LS strain (laboratory-susceptible) 24 hours post exposure period to permethrin was carried out via 1D-gel electrophoresis and liquid chromatography mass spectrometry (LC-MS/ MS). The bands which appeared in the gel of 1D-electrophoresis revealed an abundance of proteins. The band pattern of both strains looked macroscopically alike and differed only in band intensity. However, LC-MS/MS analysis revealed that the IMR-PSS strain produced extra 388 peptides that were not found in the IMR-LS strain, indicating that IMR-PSS strain reacted differently from IMR-LS strain as a result of persistent exposure to permethrin. Since the complex banding patterns of 1D-gel electrophoresis were difficult to interpret the significance of the protein difference between IMR-PSS and IMR-LS strain, hence LC-MS/MS analysis is ideally suited for better protein resolution and thus will allow more in-depth comparison of the complex pattern. The findings here provide the first preliminary evidence that insecticide resistance in mosquito induces up regulation of proteins that may be protective to mosquitoes against insecticide and proteins could be another mechanism that contributes to development of resistance.
    Matched MeSH terms: Aedes/genetics*
  4. Zawani MK, Abu HA, Sazaly AB, Zary SY, Darlina MN
    Genet. Mol. Res., 2014;13(4):8184-96.
    PMID: 25299203 DOI: 10.4238/2014.October.7.13
    The mosquito Aedes albopictus is indigenous to Southeast Asian and is a vector for arbovirus diseases. Studies examining the population genetics structure of A. albopictus have been conducted worldwide; however, there are no documented reports on the population genetic structure of A. albopictus in Malaysia, particularly in Penang. We examined the population genetics of A. albopictus based on a 445-base pair segment of the mitochondrial DNA cytochrome oxidase 1 gene among 77 individuals from 9 localities representing 4 regions (Seberang Perai Utara, Seberang Perai Tengah, Northeast, and Southwest) of Penang. A total of 37 haplotypes were detected, including 28 unique haplotypes. The other 9 haplotypes were shared among various populations. These shared haplotypes reflect the weak population genetic structure of A. albopictus. The phylogenetic tree showed a low bootstrap value with no genetic structure, which was supported by minimum spanning network analysis. Analysis of mismatch distribution showed poor fit of equilibrium distribution. The genetic distance showed low genetic variation, while pairwise FST values showed no significant difference between all regions in Penang except for some localities. High haplotype diversity and low nucleotide diversity was observed for cytochrome oxidase 1 mtDNA. We conclude that there is no population genetic structure of A. albopictus mosquitoes in the Penang area.
    Matched MeSH terms: Aedes/genetics*
  5. Hanson SM, Mutebi JP, Craig GB, Novak RJ
    J Am Mosq Control Assoc, 1993 Mar;9(1):78-83.
    PMID: 8468578
    Eggs of temperate Aedes albopictus populations are cold hardy and can diapause, but tropical populations are not cold hardy and cannot diapause. Heterozygotes possess intermediate diapause and cold hardiness. Males of a tropical strain from Malaysia with a distinctive genetic marker were released into an existing temperate population in East St. Louis, Illinois. Subsequent egg samples from the release site had genetic marker frequency of up to 24%. Reduced cold hardiness and decreased diapause incidence were also observed in the release site population. No such changes occurred at a nearby control site. The rank order of overwintering survival of eggs at the release site was: Aedes triseriatus > temperate Ae. albopictus > hybrid temperate/tropical Ae. albopictus > tropical Ae. albopictus. Eggs collected from the release population the next summer showed total absence of the genetic marker; presumably carriers were removed by the winter.
    Matched MeSH terms: Aedes/genetics*
  6. Marcela P, Hassan AA, Hamdan A, Dieng H, Kumara TK
    J Am Mosq Control Assoc, 2015 Dec;31(4):313-20.
    PMID: 26675452 DOI: 10.2987/moco-31-04-313-320.1
    Mating behavior between Aedes aegypti and Ae. albopictus, established colony strains were examined under laboratory conditions (30-cm(3) screened cages) for 5 consecutive days. The effect of selected male densities (30, 20, 10) and female density (20) on the number of swarming, mating pairs, eggs produced, and inseminated females were evaluated. Male densities significantly increased swarming behavior, mating pairs, and egg production of heterospecific females, but female insemination was reduced. Aedes aegypti males mate more readily with heterospecific females than do Ae. albopictus males. The current study suggests that Ae. aegypti males were not species-specific in mating, and if released into the field as practiced in genetically modified mosquito techniques, they may mate with both Ae. aegypti and Ae. albopictus females, hence reducing populations of both species by producing infertile eggs.
    Matched MeSH terms: Aedes/genetics
  7. Adilah-Amrannudin N, Hamsidi M, Ismail NA, Ismail R, Dom NC, Ahmad AH, et al.
    J Am Mosq Control Assoc, 2016 Dec;32(4):265-272.
    PMID: 28206858 DOI: 10.2987/16-6579.1
    This study was performed to establish the genetic variability of Aedes albopictus within Subang Jaya, Selangor, Malaysia, by using the nicotinamide adenine dinucleotide dehydrogenase 5 subunit (ND5) mitochondrial DNA (mtDNA) marker. A total of 90 samples were collected from 9 localities within an area of the Subang Jaya Municipality. Genetic variability was determined through the amplification and sequencing of a fragment of the ND5 gene. Eight distinct mtDNA haplotypes were identified. The evolutionary relationship of the local haplotypes alongside 28 reference strains was used to construct a phylogram, the analysis of which revealed low genetic differentiation in terms of both nucleotide and haplotype diversity. Bayesian method was used to infer the phylogenetic tree, revealing a unique relationship between local isolates. The study corroborates the reliability of ND5 to identify distinct lineages for polymorphism-based studies and supplements the existing body of knowledge regarding its genetic diversity. This in turn could potentially aid existing vector control strategies to help mitigate the risk and spread of the dengue virus.
    Matched MeSH terms: Aedes/genetics*
  8. Yong HS, Cheong WH, Mak JW, Chiang GL, Chan KL, Dhaliwal SS
    Biochem Genet, 1980 Oct;18(9-10):939-45.
    PMID: 7225086
    The genetics of glucosephosphate isomerase (E.C. 5.3.1.9) in two strains (Malaysian and Taiwan) of Aedes togoi is reported. Three electrophoretic phenotypes were presented in both sexes. The zymogram patterns were identical in both strains of A. togoi. The phenotypes were governed by a pair of codominant alleles. The allele frequency of the slow-moving band was 0.63 in the Malaysian strain adn was 0,86 and 0.82 in F161 and F169 generations, respectively, of the Taiwan strain. The sample studied was in good accord with Hardy-Weinberg expectation.
    Matched MeSH terms: Aedes/genetics*
  9. Amelia-Yap ZH, Sofian-Azirun M, Chen CD, Lau KW, Suana IW, Syahputra E, et al.
    J Med Entomol, 2019 06 27;56(4):953-958.
    PMID: 30942885 DOI: 10.1093/jme/tjz035
    Resistance to pyrethroid insecticides is widespread in Indonesian Aedes aegypti (Linnaeus), the primary vector of dengue viruses. This study aims to investigate the mutations in the voltage-gated sodium channel (Vgsc) conferring pyrethroid resistance against Ae. aegypti populations from Indonesia. Molecular genotyping of mutations using polymerase chain reaction assay and direct DNA sequencing were performed at positions 989 and 1,016 in IIS6 region, and 1,534 in IIIS6 region of the voltage-gated sodium channel (Vgsc) in nine populations of Indonesian Ae. aegypti. The V1016G and S989P genotyping identified the RR genotype to be predominant in six out of nine populations of Ae. aegypti, whereas the SS genotype occurred only in minority. Interestingly, co-occurrence of the V1016G and S989P mutations was detected in the aforementioned six populations with high frequency. Genotyping of F1534C showed all nine populations exhibited the SS genotype, with merely two individuals from a population were heterozygous (RS). Significant correlations were demonstrated between the allele frequencies of the V1016G mutation and the survivability rates as well as resistance ratios in pyrethroid adult bioassays. This signifies the V1016G can contribute more to the insensitivity of Vgsc than the F1534C. Homozygous 1016G mosquitoes were likelier to survive pyrethroid exposure. Identification of underlying mechanisms resulting in insecticide resistance is advantageous in developing effective mosquito control programs in Indonesia.
    Matched MeSH terms: Aedes/genetics*
  10. Chan HH, Zairi J
    J Med Entomol, 2013 Mar;50(2):362-70.
    PMID: 23540125
    Insecticide resistance has become a serious issue in vector management programs. Information on insecticidal resistance and its associated mechanisms is important for successful insecticide resistance management. The selection of a colony of permethrin-resistant Aedes albopictus (Skuse) (Diptera: Culicidae), originating from Penang Island, Malaysia, yielded high larval-specific resistance to permethrin and cross-resistance to deltamethrin. Synergism assays showed that the major mechanism underlying this resistance involves cytochrome P450 monooxygenase. The resistance is autosomal, polygenically inherited and incompletely dominant (D = 0.26). Resistant larvae were reared under different conditions to assess the fitness costs. Under high larval density, larval development time of the resistant SGI strain was significantly longer than the susceptible VCRU strain. In both high- and low-density conditions SGI showed a lower rate of emergence and survival compared with the VCRU strain. Resistant larvae were more susceptible to predation by Toxorhynchites splendens (Wiedemann) (Diptera: Culicidae) larvae. The body size of SGI females reared under high-density conditions was larger compared with females of the susceptible strain. SGI females survived longer when starved than did VCRU females. The energy reserve upon eclosion was positively correlated with the size of the adults.
    Matched MeSH terms: Aedes/genetics*
  11. Subramaniam TS, Lee HL, Ahmad NW, Murad S
    Biotechnol J, 2012 Nov;7(11):1323-7.
    PMID: 23125042 DOI: 10.1002/biot.201200282
    On December 21, 2010, 6000 genetically modified (GM) mosquitoes were released in an uninhabited forest in Malaysia. The purpose of the deliberate release was a limited “marked release and recapture” (MRR) experiment, a standard ecological method in entomology, to evaluate under field conditions, the flight distance and longevity of the sterile male Aedes aegypti strain OX513A(My1), a GM strain. As with any other GM technologies, the release was received with mixed responses. As the scientific community debate over the public engagement strategies for similar GM releases, dengue incidence continues to rise with a heavy toll on morbidity, mortality and healthcare budgets. Meanwhile the wild female Aedes aegypti continues to breed offspring, surviving and evading conventional interventions for vector control.
    Matched MeSH terms: Aedes/genetics*
  12. Lacroix R, McKemey AR, Raduan N, Kwee Wee L, Hong Ming W, Guat Ney T, et al.
    PLoS One, 2012;7(8):e42771.
    PMID: 22970102 DOI: 10.1371/journal.pone.0042771
    Dengue is the most important mosquito-borne viral disease. In the absence of specific drugs or vaccines, control focuses on suppressing the principal mosquito vector, Aedes aegypti, yet current methods have not proven adequate to control the disease. New methods are therefore urgently needed, for example genetics-based sterile-male-release methods. However, this requires that lab-reared, modified mosquitoes be able to survive and disperse adequately in the field.
    Matched MeSH terms: Aedes/genetics*
  13. Cyranoski D
    Nature, 2008 May 22;453(7194):435.
    PMID: 18497781 DOI: 10.1038/453435a
    Matched MeSH terms: Aedes/genetics
  14. Winskill P, Carvalho DO, Capurro ML, Alphey L, Donnelly CA, McKemey AR
    PLoS Negl Trop Dis, 2015 Nov;9(11):e0004156.
    PMID: 26554922 DOI: 10.1371/journal.pntd.0004156
    BACKGROUND: Aedes aegypti, the principal vector of dengue fever, have been genetically engineered for use in a sterile insect control programme. To improve our understanding of the dispersal ecology of mosquitoes and to inform appropriate release strategies of 'genetically sterile' male Aedes aegypti detailed knowledge of the dispersal ability of the released insects is needed.

    METHODOLOGY/PRINCIPAL FINDINGS: The dispersal ability of released 'genetically sterile' male Aedes aegypti at a field site in Brazil has been estimated. Dispersal kernels embedded within a generalized linear model framework were used to analyse data collected from three large scale mark release recapture studies. The methodology has been applied to previously published dispersal data to compare the dispersal ability of 'genetically sterile' male Aedes aegypti in contrasting environments. We parameterised dispersal kernels and estimated the mean distance travelled for insects in Brazil: 52.8 m (95% CI: 49.9 m, 56.8 m) and Malaysia: 58.0 m (95% CI: 51.1 m, 71.0 m).

    CONCLUSIONS/SIGNIFICANCE: Our results provide specific, detailed estimates of the dispersal characteristics of released 'genetically sterile' male Aedes aegypti in the field. The comparative analysis indicates that despite differing environments and recapture rates, key features of the insects' dispersal kernels are conserved across the two studies. The results can be used to inform both risk assessments and release programmes using 'genetically sterile' male Aedes aegypti.

    Matched MeSH terms: Aedes/genetics*
  15. Avicor SW, Wajidi MF, Jaal Z, Yahaya ZS
    Acta Biochim. Pol., 2016;63(2):243-6.
    PMID: 27059016 DOI: 10.18388/abp.2014_909
    Septins belong to GTPases that are involved in vital cellular activities, including cytokinesis. Although present in many organisms, they are yet to be isolated from Aedes albopictus. This study reports for the first time on a serendipitous isolation of a partial septin sequence from Ae. albopictus and its developmental expression profile. The Ae. albopictus partial septin sequence contains 591 nucleotides encoding 197 amino acids. It shares homology with several insect septin genes and has a close phylogenetic relationship with Aedes aegypti and Culex quinquefasciatus septins. The Ae. albopictus septin fragment was differentially expressed in the mosquito's developmental stages, with an increased expression in the adults.
    Matched MeSH terms: Aedes/genetics*
  16. Sota T, Belton P, Tseng M, Yong HS, Mogi M
    PLoS One, 2015;10(6):e0131230.
    PMID: 26107619 DOI: 10.1371/journal.pone.0131230
    The coastal mosquito Aedes togoi occurs more or less continuously from subarctic to subtropic zones along the coasts of the Japanese islands and the East Asian mainland. It occurs also in tropical Southeast Asia and the North American Pacific coast, and the populations there are thought to have been introduced from Japan by ship. To test this hypothesis, the genetic divergence among geographic populations of A. togoi was studied using one mitochondrial and three nuclear gene sequences. We detected 71 mitochondrial haplotypes forming four lineages, with high nucleotide diversity around temperate Japan and declining towards peripheral ranges. The major lineage (L1) comprised 57 haplotypes from temperate and subarctic zones in Japan and Southeast Asia including southern China and Taiwan. Two other lineages were found from subtropical islands (L3) and a subarctic area (L4) of Japan. The Canadian population showed one unique haplotype (L2) diverged from the other lineages. In the combined nuclear gene tree, individuals with mitochondrial L4 haplotypes diverged from those with the other mitochondrial haplotypes L1-L3; although individuals with L1-L3 haplotypes showed shallow divergences in the nuclear gene sequences, individuals from Southeast Asia and Canada each formed a monophyletic group. Overall, the genetic composition of the Southeast Asian populations was closely related to that of temperate Japanese populations, suggesting recent gene flow between these regions. The Canadian population might have originated from anthropogenic introduction from somewhere in Asia, but the possibility that it could have spread across the Beringian land bridge cannot be ruled out.
    Matched MeSH terms: Aedes/genetics*
  17. Avicor SW, Wajidi MF, El-Garj FM, Jaal Z, Yahaya ZS
    Protein J, 2014 Oct;33(5):457-64.
    PMID: 25199940 DOI: 10.1007/s10930-014-9580-z
    Mosquito coils are insecticides commonly used for protection against mosquitoes due to their toxic effects on mosquito populations. These effects on mosquitoes could induce the expression of metabolic enzymes in exposed populations as a counteractive measure. Cytochrome P450 family 4 (CYP4) are metabolic enzymes associated with a wide range of biological activities including insecticide resistance. In this study, the efficacies of three commercial mosquito coils with different pyrethroid active ingredients were assessed and their potential to induce the expression of CYP4 genes in Aedes albopictus analyzed by real-time quantitative PCR. Coils containing 0.3 % D-allethrin and 0.005 % metofluthrin exacted profound toxic effects on Ae. albopictus, inducing high mortalities (≥90 %) compared to the 0.2 % D-allethrin reference coil. CYP4H42 and CYP4H43 expressions were significantly higher in 0.3 % D-allethrin treated mosquitoes compared to the other treated populations. Short-term (KT50) exposure to mosquito coils induced significantly higher expression of both genes in 0.005 % metofluthrin exposed mosquitoes. These results suggest the evaluated products provided better protection than the reference coil; however, they also induced the expression of metabolic genes which could impact negatively on personal protection against mosquito.
    Matched MeSH terms: Aedes/genetics
  18. Azlan A, Obeidat SM, Yunus MA, Azzam G
    Sci Rep, 2019 08 21;9(1):12147.
    PMID: 31434910 DOI: 10.1038/s41598-019-47506-9
    Long noncoding RNAs (lncRNAs) play diverse roles in biological processes. Aedes aegypti (Ae. aegypti), a blood-sucking mosquito, is the principal vector responsible for replication and transmission of arboviruses including dengue, Zika, and Chikungunya virus. Systematic identification and developmental characterisation of Ae. aegypti lncRNAs are still limited. We performed genome-wide identification of lncRNAs, followed by developmental profiling of lncRNA in Ae. aegypti. We identified a total of 4,689 novel lncRNA transcripts, of which 2,064, 2,076, and 549 were intergenic, intronic, and antisense respectively. Ae. aegypti lncRNAs share many characteristics with other species including low expression, low GC content, short in length, and low conservation. Besides, the expression of Ae. aegypti lncRNAs tend to be correlated with neighbouring and antisense protein-coding genes. A subset of lncRNAs shows evidence of maternal inheritance; hence, suggesting potential role of lncRNAs in early-stage embryos. Additionally, lncRNAs show higher tendency to be expressed in developmental and temporal specific manner. The results from this study provide foundation for future investigation on the function of Ae. aegypti lncRNAs.
    Matched MeSH terms: Aedes/genetics*
  19. Jasper M, Schmidt TL, Ahmad NW, Sinkins SP, Hoffmann AA
    Mol Ecol Resour, 2019 Sep;19(5):1254-1264.
    PMID: 31125998 DOI: 10.1111/1755-0998.13043
    Understanding past dispersal and breeding events can provide insight into ecology and evolution and can help inform strategies for conservation and the control of pest species. However, parent-offspring dispersal can be difficult to investigate in rare species and in small pest species such as mosquitoes. Here, we develop a methodology for estimating parent-offspring dispersal from the spatial distribution of close kin, using pairwise kinship estimates derived from genome-wide single nucleotide polymorphisms (SNPs). SNPs were scored in 162 Aedes aegypti (yellow fever mosquito) collected from eight close-set, high-rise apartment buildings in an area of Malaysia with high dengue incidence. We used the SNPs to reconstruct kinship groups across three orders of kinship. We transformed the geographical distances between all kin pairs within each kinship category into axial standard deviations of these distances, then decomposed these into components representing past dispersal events. From these components, we isolated the axial standard deviation of parent-offspring dispersal and estimated neighbourhood area (129 m), median parent-offspring dispersal distance (75 m) and oviposition dispersal radius within a gonotrophic cycle (36 m). We also analysed genetic structure using distance-based redundancy analysis and linear regression, finding isolation by distance both within and between buildings and estimating neighbourhood size at 268 individuals. These findings indicate the scale required to suppress local outbreaks of arboviral disease and to target releases of modified mosquitoes for mosquito and disease control. Our methodology is readily implementable for studies of other species, including pests and species of conservation significance.
    Matched MeSH terms: Aedes/genetics*
  20. Sherpa S, Blum MGB, Després L
    Evolution, 2019 09;73(9):1793-1808.
    PMID: 31313825 DOI: 10.1111/evo.13801
    Adaptation to environmental conditions within the native range of exotic species can condition the invasion success of these species outside their range. The striking success of the Asian tiger mosquito, Aedes albopictus, to invade temperate regions has been attributed to the winter survival of diapause eggs in cold environments. In this study, we evaluate genetic polymorphisms (SNPs) and wing morphometric variation among three biogeographical regions of the native range of A. albopictus. Reconstructed demographic histories of populations show an initial expansion in Southeast Asia and suggest that marine regression during late Pleistocene and climate warming after the last glacial period favored expansion of populations in southern and northern regions, respectively. Searching for genomic signatures of selection, we identified significantly differentiated SNPs among which several are located in or within 20 kb distance from candidate genes for cold adaptation. These genes involve cellular and metabolic processes and several of them have been shown to be differentially expressed under diapausing conditions. The three biogeographical regions also differ for wing size and shape, and wing size increases with latitude supporting Bergmann's rule. Adaptive genetic and morphometric variation observed along the climatic gradient of A. albopictus native range suggests that colonization of northern latitudes promoted adaptation to cold environments prior to its worldwide invasion.
    Matched MeSH terms: Aedes/genetics*
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