Last data update: May 06, 2024. (Total: 46732 publications since 2009)
Records 1-13 (of 13 Records) |
Query Trace: Kothera L[original query] |
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Comparative transcriptomic analysis of insecticide-resistant Aedes aegypti from Puerto Rico reveals insecticide-specific patterns of gene expression
Derilus D , Impoinvil LM , Muturi EJ , McAllister J , Kenney J , Massey SE , Hemme R , Kothera L , Lenhart A . Genes (Basel) 2023 14 (8) Aedes aegypti transmits major arboviruses of public health importance, including dengue, chikungunya, Zika, and yellow fever. The use of insecticides represents the cornerstone of vector control; however, insecticide resistance in Ae. aegypti has become widespread. Understanding the molecular basis of insecticide resistance in this species is crucial to design effective resistance management strategies. Here, we applied Illumina RNA-Seq to study the gene expression patterns associated with resistance to three widely used insecticides (malathion, alphacypermethrin, and lambda-cyhalothrin) in Ae. aegypti populations from two sites (Manatí and Isabela) in Puerto Rico (PR). Cytochrome P450s were the most overexpressed detoxification genes across all resistant phenotypes. Some detoxification genes (CYP6Z7, CYP28A5, CYP9J2, CYP6Z6, CYP6BB2, CYP6M9, and two CYP9F2 orthologs) were commonly overexpressed in mosquitoes that survived exposure to all three insecticides (independent of geographical origin) while others including CYP6BY1 (malathion), GSTD1 (alpha-cypermethrin), CYP4H29 and GSTE6 (lambda-cyhalothrin) were uniquely overexpressed in mosquitoes that survived exposure to specific insecticides. The gene ontology (GO) terms associated with monooxygenase, iron binding, and passive transmembrane transporter activities were significantly enriched in four out of six resistant vs. susceptible comparisons while serine protease activity was elevated in all insecticide-resistant groups relative to the susceptible strain. Interestingly, cuticular-related protein genes (chinase and chitin) were predominantly downregulated, which was also confirmed in the functional enrichment analysis. This RNA-Seq analysis presents a detailed picture of the candidate detoxification genes and other pathways that are potentially associated with pyrethroid and organophosphate resistance in Ae. aegypti populations from PR. These results could inform development of novel molecular tools for detection of resistance-associated gene expression in this important arbovirus vector and guide the design and implementation of resistance management strategies. |
Mosquito control activities during local transmission of Zika virus, Miami-Dade County, Florida, USA, 2016
McAllister JC , Porcelli M , Medina JM , Delorey MJ , Connelly CR , Godsey MS , Panella NA , Dzuris N , Boegler KA , Kenney JL , Kothera L , Vizcaino L , Lenhart AE , Mutebi JP , Vasquez C . Emerg Infect Dis 2020 26 (5) 881-890 In 2016, four clusters of local mosquitoborne Zika virus transmission were identified in Miami-Dade County, Florida, USA, generating "red zones" (areas into which pregnant women were advised against traveling). The Miami-Dade County Mosquito Control Division initiated intensive control activities, including property inspections, community education, and handheld sprayer applications of larvicides and adulticides. For the first time, the Mosquito Control Division used a combination of areawide ultralow-volume adulticide and low-volume larvicide spraying to effectively control Aedes aegypti mosquitoes, the primary Zika virus vector within the county. The number of mosquitoes rapidly decreased, and Zika virus transmission was interrupted within the red zones immediately after the combination of adulticide and larvicide spraying. |
Bloodmeal, Host Selection, and Genetic Admixture Analyses of Culex pipiens Complex (Diptera: Culicidae) Mosquitoes in Chicago, IL.
Kothera L , Mutebi JP , Kenney JL , Saxton-Shaw K , Ward MP , Savage HM . J Med Entomol 2019 57 (1) 78-87 The area in and around Chicago, IL, is a hotspot of West Nile virus activity. The discovery of a Culex pipiens form molestus Forskl population in Chicago in 2009 added to speculation that offspring from hybridization between Cx. pipiens f. pipiens L. and f. molestus could show a preference for feeding on humans. We collected blood-fed female mosquitoes (N = 1,023) from eight residential sites and one public park site in Chicago in July and August 2012. Bloodmeal analysis using the COI (cytochrome c oxidase subunit I) gene was performed to ascertain host choice. Almost all (99%) bloodmeals came from birds, with American Robins (Turdus migratorius L.) and House Sparrows (Passer domesticus L.) making up the largest percentage (74% combined). A forage ratio analysis comparing bird species fed upon and available bird species based on point count surveys indicated Northern Cardinals (Cardinalis cardinalis) and American Robins (Turdus migratorius) appeared to be over-utilized, whereas several species were under-utilized. Two human bloodmeals came from Culex pipiens complex mosquitoes. Admixture and population genetic analyses were conducted with 15 microsatellite loci on head and thorax DNA from the collected blood-fed mosquitoes. A modest amount of hybridization was detected between Cx. pipiens f. pipiens and f. molestus, as well as between f. pipiens and Cx. quinquefasciatus Say. Several pure Cx. quinquefasciatus individuals were noted at the two Trumbull Park sites. Our data suggest that Cx. pipiens complex mosquitoes in the Chicago area are not highly introgressed with f. molestus and appear to utilize avian hosts. |
Using targeted next-generation sequencing to characterize genetic differences associated with insecticide resistance in Culex quinquefasciatus populations from the southern U.S.
Kothera L , Phan J , Ghallab E , Delorey M , Clark R , Savage HM . PLoS One 2019 14 (7) e0218397 Resistance to insecticides can hamper the control of mosquitoes such as Culex quinquefasciatus, known to vector arboviruses such as West Nile virus and others. The strong selective pressure exerted on a mosquito population by the use of insecticides can result in heritable genetic changes associated with resistance. We sought to characterize genetic differences between insecticide resistant and susceptible Culex quinquefasciatus mosquitoes using targeted DNA sequencing. To that end, we developed a panel of 122 genes known or hypothesized to be involved in insecticide resistance, and used an Ion Torrent PGM sequencer to sequence 125 unrelated individuals from seven populations in the southern U.S. whose resistance phenotypes to permethrin and malathion were known from previous CDC bottle bioassay testing. Data analysis consisted of discovering SNPs (Single Nucleotide Polymorphism) and genes with evidence of copy number variants (CNVs) statistically associated with resistance. Ten of the seventeen genes found to be present in higher copy numbers were experimentally validated with real-time PCR. Of those, six, including the gene with the knock-down resistance (kdr) mutation, showed evidence of a >/= 1.5 fold increase compared to control DNA. The SNP analysis revealed 228 unique SNPs that had significant p-values for both a Fisher's Exact Test and the Cochran-Armitage Test for Trend. We calculated the population frequency for each of the 64 nonsynonymous SNPs in this group. Several genes not previously well characterized represent potential candidates for diagnostic assays when further validation is conducted. |
Zika virus MB16-23 in mosquitoes, Miami-Dade County, Florida, USA, 2016
Mutebi JP , Hughes HR , Burkhalter KL , Kothera L , Vasquez C , Kenney JL . Emerg Infect Dis 2018 24 (4) 808-10 We isolated a strain of Zika virus, MB16-23, from Aedes aegypti mosquitoes collected in Miami Beach, Florida, USA, on September 2, 2016. Phylogenetic analysis suggests that MB16-23 most likely originated from the Caribbean region. |
Duplex Real-Time PCR Assay Distinguishes Aedes aegypti From Ae. albopictus (Diptera: Culicidae) Using DNA From Sonicated First-Instar Larvae.
Kothera L , Byrd B , Savage HM . J Med Entomol 2017 54 (6) 1567-1572 Aedes aegypti (L.) and Ae. albopictus (Skuse) are important arbovirus vectors in the United States, and the recent emergence of Zika virus disease as a public health concern in the Americas has reinforced a need for tools to rapidly distinguish between these species in collections made by vector control agencies. We developed a duplex real-time PCR assay that detects both species and does not cross-amplify in any of the other seven Aedes species tested. The lower limit of detection for our assay is equivalent to approximately 0.03 of a first-instar larva in a 60-microl sample (0.016 ng of DNA per real-time PCR reaction). The assay was sensitive and specific in mixtures of both species that reflected up to a 2,000-fold difference in DNA concentration. In addition, we developed a simple protocol to extract DNA from sonicated first-instar larvae, and used that DNA to test the assay. Because it uses real-time PCR, the assay saves time by not requiring a separate visualization step. This assay can reduce the time needed for vector control agencies to make species identifications, and thus inform decisions about surveillance and control. |
Population genetic and admixture analyses of Culex pipiens complex (Diptera: Culicidae) populations in California, United States.
Kothera L , Nelms BM , Reisen WK , Savage HM . Am J Trop Med Hyg 2013 89 (6) 1154-67 Microsatellite markers were used to genetically characterize 19 Culex pipiens complex populations from California. Two populations showed characteristics of earlier genetic bottlenecks. The overall FST value and a neighbor-joining tree suggested moderate amounts of genetic differentiation. Analyses using Structure indicated K = 4 genetic clusters: Cx. pipiens form pipiens L., Cx. quinquefasciatus Say, Cx. pipiens form molestus Forskal, and a group of genetically similar individuals of hybrid origin. A Discriminant Analysis of Principal Components indicated that the latter group is a mixture of the other three taxa, with form pipiens and form molestus contributing somewhat more ancestry than Cx. quinquefasciatus. Characterization of 56 morphologically autogenous individuals classified most as Cx. pipiens form molestus, and none as Cx. pipiens form pipiens or Cx. quinquefasciatus. Comparison of California microsatellite data with those of Cx. pipiens pallens Coquillett from Japan indicated the latter does not contribute significantly to genotypes in California. |
Phenotypic variation among Culex pipiens complex (Diptera: Culicidae) populations from the Sacramento Valley, California: horizontal and vertical transmission of West Nile virus, diapause potential, autogeny, and host selection
Nelms BM , Kothera L , Thiemann T , Macedo PA , Savage HM , Reisen WK . Am J Trop Med Hyg 2013 89 (6) 1168-78 The vector competence and bionomics of Culex pipiens form pipiens L. and Cx. pipiens f. molestus Forskal were evaluated for populations from the Sacramento Valley. Both f. pipiens and f. molestus females became infected, produced disseminated infections, and were able to transmit West Nile virus. Form molestus females also transmitted West Nile virus vertically to egg rafts and F1 progeny, whereas f. pipiens females only transmitted to egg rafts. Culex pipiens complex from urban Sacramento blood-fed on seven different avian species and two mammalian species. Structure analysis of blood-fed mosquitoes identified K = 4 genetic clusters: f. molestus, f. pipiens, a group of genetically similar hybrids (Cluster X), and admixed individuals. When females were exposed as larvae to midwinter conditions in bioenvironmental chambers, 85% (N = 79) of aboveground Cx. pipiens complex females and 100% (N = 34) of underground f. molestus females did not enter reproductive diapause. |
A comparison of above-ground and below-ground populations of Culex pipiens pipiens in Chicago, Illinois, and New York City, New York, using 2 microsatellite assays
Kothera L , Godsey M , Mutebi JP , Savage HM . J Am Mosq Control Assoc 2012 28 106-12 Aboveground and belowground populations of the mosquito Culex pipiens pipiens are traditionally classified as form (f.) pipiens and f. molestus, respectively, and gene flow between forms is thought to be limited. Relatively few f. molestus populations have been found in the United States, which has hindered their study in North America. In this investigation, we used microsatellites to characterize a recently discovered population of f. molestus in Chicago, IL, and compared levels of genetic diversity and differentiation in above-ground and below-ground populations from Chicago and New York City, NY. Levels of genetic diversity were markedly lower in both f. molestus populations. Pairwise F(ST) values between populations indicated that f. molestus populations were highly divergent from each other, as well as from their associated aboveground populations. The most likely number of genetic clusters depended on the number of loci used; we began with a set of 8, and reanalyzed the specimens with 17. Using a panel of 17 loci, there were 4 clusters, 1 for each below-ground population, and 1 for each pair of above-ground populations. Our findings are supportive of the hypothesis that f. molestus populations in Chicago and New York City arose from local aboveground populations. |
The Culex pipiens complex in the Mississippi River basin: identification, distribution, and bloodmeal hosts
Savage HM , Kothera L . J Am Mosq Control Assoc 2012 28 93-9 Members of the Culex pipiens complex are the primary vectors of St. Louis encephalitis virus and West Nile virus in the Mississippi River basin (MRB). The Cx. pipiens complex in the MRB is composed of 4 taxa: Cx. p. pipiens form pipiens, Cx. p. quinquefasciatus, hybrids between Cx. p. pipiens f. pipiens and Cx. p. quinquefasciatus, and Cx. p. pipiens form molestus. Three studies on bloodmeal hosts with large sample sizes have been conducted on members of the Cx. pipiens complex in the MRB including 1 each on Cx. p. quinquefasciatus from Louisiana, Cx. p. pipiens-quinquefasciatus hybrids from Tennessee, and Cx. p. pipiens from Illinois. The top 8 bloodmeal hosts from each of the 3 sites accounted for 68-92% of bloodmeals. Only 14 species accounted for the top 8 bloodmeal hosts at each of the 3 sites. The most often utilized bloodmeal hosts for members of the Culex pipiens complex within the MRB are the American robin, Northern cardinal, human, raccoon, common grackle, house sparrow, mourning dove, dog, Northern mockingbird, blue jay, opossum, domestic horse, house finch and European starling. Human feeding varied widely among sites from 1% to 15.7% of bloodmeals. The proportion of bloodmeals taken on humans is an important epidemiological variable and future studies are needed to define the primary genetic and environmental factors that influence host utilization by members of the Cx. pipiens complex. |
Characterization of Culex pipiens complex (Diptera: Culicidae) populations in Colorado, USA using microsatellites
Kothera L , Godsey MS Jr , Doyle MS , Savage HM . PLoS One 2012 7 (10) e47602 Mosquitoes such as those in the Culex pipiens complex are important vectors of disease. This study was conducted to genetically characterize Cx. pipiens complex populations in the state of Colorado, USA, and to determine the number of genetic clusters represented by the data. Thirteen populations located among four major river basins were sampled (n = 597 individuals) using a panel of 14 microsatellites. The lowest-elevation sites had the highest Expected Heterozygosity (H(E)) values (range 0.54-0.65). AMOVA results indicated the presence of statistically significant amounts of variation within each level when populations were analyzed as one group or when they were grouped either by river basin or by their position on the east or west side of the Rocky Mountains. Most pairwise F(ST) values were significant via permutation test (range 0-0.10), with the highest values from comparisons with Lamar, in southeast CO. A neighbor joining tree based on Cavalli-Sforza and Edwards's chord distances was consistent with the geographic locations of populations, as well as with the AMOVA results. There was a significant isolation by distance effect, and the cluster analysis resolved five groups. Individuals were also assayed with an additional microsatellite marker, Cxpq78, proposed to be monomorphic in Cx. pipiens but polymorphic in the closely related but biologically distinct species Cx. quinquefasciatus. Low frequencies (≤3%) of Cx. quinquefasciatus alleles for this marker were noted, and mostly confined to populations along the Interstate 25 corridor. Pueblo was distinct in that it had 10% Cx. quinquefasciatus alleles, mostly of one allele size. The degree of population genetic structure observed in this study is in contrast with that of Cx. tarsalis, the other major vector of WNV in the western U.S., and likely reflects the two species' different dispersal strategies. |
Permanent genetic resources added to Molecular Ecology Resources Database 1 October 2011-30 November 2011.
Molecular Ecology Resources Primer Development Consortium , Abreu AG , Albaina A , Alpermann TJ , Apkenas VE , Bankhead-Dronnet S , Bergek S , Berumen ML , Cho CH , Clobert J , Coulon A , DEFeraudy D , Estonba A , Hankeln T , Hochkirch A , Hsu TW , Huang TJ , Irigoien X , Iriondo M , Kay KM , Kinitz T , Kothera L , LEHenanff M , Lieutier F , Lourdais O , Macrini CM , Manzano C , Martin C , Morris VR , Nanninga G , Pardo MA , Plieske J , Pointeau S , Prestegaard T , Quack M , Richard M , Savage HM , Schwarcz KD , Shade J , Simms EL , Solferini VN , Stevens VM , Veith M , Wen MJ , Wicker F , Yost JM , Zarraonaindia I . Mol Ecol Resour 2012 12 (2) 374-6 This article documents the addition of 139 microsatellite marker loci and 90 pairs of single-nucleotide polymorphism sequencing primers to the Molecular Ecology Resources Database. Loci were developed for the following species: Aglaoctenus lagotis, Costus pulverulentus, Costus scaber, Culex pipiens, Dascyllus marginatus, Lupinus nanus Benth, Phloeomyzus passerini, Podarcis muralis, Rhododendron rubropilosum Hayata var. taiwanalpinum and Zoarces viviparus. These loci were cross-tested on the following species: Culex quinquefasciatus, Rhododendron pseudochrysanthum Hay. ssp. morii (Hay.) Yamazaki and R. pseudochrysanthum Hayata. This article also documents the addition of 48 sequencing primer pairs and 90 allele-specific primers for Engraulis encrasicolus. |
A comparison of aboveground and belowground populations of Culex pipiens (Diptera: Culicidae) mosquitoes in Chicago, Illinois, and New York City, New York, using microsatellites
Kothera L , Godsey M , Mutebi JP , Savage HM . J Med Entomol 2010 47 (5) 805-813 Aboveground and belowground populations of the mosquito Culex pipiens L. are traditionally classified as form pipiens and form molestus, respectively, and gene flow between forms is thought to be limited. Relatively few f. molestus populations have been found in the United States, which has hindered their study in North America. In this study, we used microsatellites to characterize a newly discovered population of f. molestus in Chicago, IL, and compared levels of genetic diversity and differentiation in aboveground and belowground populations from Chicago and New York City, NY. Levels of genetic diversity, as measured by expected heterozygosity and allelic richness, were markedly lower in both f. molestus populations. Allele frequencies were distinctly different between the two f. molestus populations, and some alleles were present in one belowground population and not the other. Pairwise FST values between populations indicated that f. molestus populations were highly divergent from each other, as well as from their associated aboveground populations. Cluster analysis suggested the most likely number of groups was three, with the four f. pipiens populations in one cluster, and each of the f. molestus populations in its own cluster. Admixture analysis detected a low number of hybrids, 8%, between forms. We also tested the efficacy of two assays purported to distinguish between the forms, the CQ11 assay and a restriction fragment-length polymorphism assay of the COI gene, and found neither assay reliable in this regard. Our findings support the hypothesis that f. molestus populations in Chicago and New York City arose from local aboveground populations. |
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