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The establishment of a productive dengue virus (DENV) infection in the midgut epithelial cells of Aedes aegypti is critical for the viral transmission cycle. The hypothesis that DENV virions interact directly with specific mosquito midgut proteins was explored. We found that DENV serotype 2 (DENV2) pretreated with trypsin interacted with a single 31 kDa protein, identified as AAEL011180 by protein mass spectrometry. This putative receptor is a highly conserved protein and has orthologs in culicine and anopheline mosquitoes. We confirmed that impairing the expression of AAEL011180 in the midgut of Ae. aegypti females abolished the interaction with DENV2, and the virus also bound to immobilized recombinant purified receptor. Furthermore, recombinant DENV2 surface E glycoprotein bound to recombinant AAEL011180 with high affinity (38.2 nM) in binding kinetic analysis using surface plasmon resonance. The gene for this DENV2 E protein receptor (EPrRec) was disrupted, but since the gene is essential in Ae. aegypti, only heterozygote knockout (ΔEPrRec+/−) females could be recovered. Further reducing EPrRec mRNA expression in the midgut of ΔEPrRec+/− females by systemic dsRNA injection significantly reduced the prevalence of DENV2 midgut infection. EPrRec also interacts with heat shock protein 70 cognate 3 (Hsc70-3), and silencing Hsc70-3 expression in ΔEPrRec females also reduced the prevalence of DENV2 midgut infection. [ABSTRACT FROM AUTHOR]

Optically clear, ultrathin monoliths that contained the single-tryptophan protein monellin were prepared by the sol-gel technique from tetraethyl orthosilicate (TEOS). Suitable precautions were established to eliminate background fluorescence from impurities in TEOS, scattering from the monoliths, and photobleaching of the entrapped protein. Fluorescence spectra and anisotropy results indicated that useful, essentially scatter-free fluorescence signals could be obtained from the intrinsic tryptophan residue of monellin which was entrapped into either wet-aged or dry-aged monoliths. The combination of spectral, quenching, and anisotropy results suggested that the mobility of solvent inside monoliths was substantially reduced compared to bulk solution, providing a possible explanation for the improvements in protein stability that occur upon entrapment. The monitoring of intrinsic protein fluorescence also provided information about the kinetics of the interaction between the entrapped protein and external reagents. The interaction of monellin with both neutral and charged species was examined under conditions of continuous stirring and indicated response times on the order of minutes. In the case of the neutral species, the kinetics were best described by a sum of first-order rate constants when the reactions occurred in the glass matrix. For charged species, interactions between the analytes and the negatively charged glass matrix caused the reaction kinetics to become complex, with the overall reaction rate depending on both the type of aging and the charge on the analyte. These findings suggest that caution must be exercised when entrapped proteins are used for sensing of charged species.

BACKGROUND: Neonicotinoids are the largest class of insecticides and are used for control of house fly populations at animal production facilities throughout the world. There have been several reports of neonicotinoid resistance in house fly populations, but identification of the factors involved in resistance has proven challenging. The KS8S3 population of house flies is highly resistant to the neonicotinoid insecticide imidacloprid due to two factors: one on chromosome 3 and one on chromosome 4. RESULTS: A comparative transcriptomic approach was used, followed by validation using transgenic Drosophila melanogaster to investigate the genes responsible for resistance in the KS8S3 strain. Overexpression of a microsomal glutathione S‐transferase (Mdgst) was identified as the factor likely responsible for resistance on chromosome 3. Resistance on chromosome 4 appears to be due to an unidentified trans‐regulatory gene which causes overexpression of a galactosyltransferase‐like gene (Mdgt1). No single nucleotide polymorphisms were found that could be associated with imidacloprid resistance. CONCLUSION: Identification of the underlying processes that cause imidacloprid resistance is an important first step towards the development of novel and sensitive resistance monitoring techniques. It will be valuable to investigate if overexpression of Mdgst and Mdgt1 are found in other imidacloprid resistant populations. © 2018 Society of Chemical Industry Venn diagram of the total number of genes over‐ and under‐expressed relative to the insecticide susceptible aabys strain. [ABSTRACT FROM AUTHOR]

Insecticide resistance is a major obstacle to the management of disease-vectoring mosquitoes worldwide. The genetic changes and detoxification genes involved in insecticide resistance have been extensively studied in populations of insecticide-resistant mosquitoes, however few studies have focused on the resistance genes upregulated upon insecticide exposure and the possible regulation pathways involved in insecticide resistance. To characterize the changes in gene expression during insecticide exposure, and to investigate the possible connection of known regulation pathways with insecticide resistance, we conducted RNA-Seq analysis of a highly permethrin-resistant strain of Culex quinquefasciatus following permethrin exposure. Gene expression profiles revealed a total of 224 upregulated and 146 downregulated genes when compared to a blank acetone carrier treated control, respectively, suggesting that there were multiple, but specific genes involved in permethrin resistance. Functional enrichment analysis showed that the upregulated genes contained multiple detoxification genes including a glutathione S-transferase and multiple cytochrome P450 genes, as well as several immune-related genes, while the downregulated genes consisted primarily of proteases and carbohydrate metabolism and transport. Further analysis showed that permethrin exposure resulted in a decrease in the expression of serum storage proteins and likely represented a delay in the development of the fourth instar possibly due to a decrease in feeding. This effect was more pronounced in an insecticide-resistant strain than in an insecticide-susceptible strain and may represent a behavioral mechanism of insecticide resistance in Culex mosquitoes. [ABSTRACT FROM AUTHOR]

We investigated the influence of teacher wait-time and intertrial durations on the performance of 4 multiply handicapped students during instruction in 10 skills. Four experimental conditions were evaluated: long wait-time and long intertrial interval, long wait-time and short intertrial interval. Instructors attempted to keep short intervals as close as possible to 1 s and long intervals as close as possible to 10 s for both variables. Results showed that student performance was superior under the long wait-time conditions irrespective o f the length of the intertrial interval. DESCRIPTORS: intertrial interval, wait-time, children, alternating treatment, instructional pacing

Bed bugs, Cimex lectularius L., are a major pest in the urban environment. Their presence often results in physical, psychological, and financial distress of homeowners and apartment dwellers. Although many insecticide bioassays have been performed on this pest, little attention has been paid to bed bug feeding status, which is closely linked to metabolism, molting, and mass. Therefore, we evaluated the toxicity of topically applied deltamethrin on insecticide susceptible adult male bed bugs fed 2 d, 9 d, and 21 d prior to testing. When toxicity was evaluated on a "per-bug" basis, there was no difference between 2 d [LD50 = 0.498 (0.316 - 0.692) ng.bug-1] and 9 d [LD50 = 0.572 (0.436 - 0.724) ng.bug-1] starved bugs, while 21 d starved bugs had a significantly lower LD50 [0.221 (0.075 - 0.386) ng.bug-1]. When toxicity was evaluated in terms of body mass, 9 d starved bugs had the highest LD50 values [0.138 (0.102 - 0.176) ng.mg-1], followed by 2 d starved bugs [0.095 (0.060 - 0.134) ng.mg-1], and then 21 d starved bugs [0.058 (0.019-0.102) ng.mg-1]; the LD50 values of 2 d and 9 d starved bugs were significantly different from 21 d starved bugs. These results indicate that feeding status plays an important role in the toxicity of deltamethrin. In addition, the lack of differences between 2 d and 9 d starved bugs indicate that the blood meal itself has little impact on tolerance, but rather it is some physiological change following feeding that confers increased tolerance to bed bugs. [ABSTRACT FROM AUTHOR]

Background Studies suggest that not only is insecticide resistance conferred via multiple gene upregulation, but it is mediated through the interaction of regulatory factors. However, no regulatory factors in insecticide resistance have yet been identified, and there has been no examination of the regulatory interaction of resistance genes. Our current study generated the first reference transcriptome from the adult house fly and conducted a whole transcriptome analysis for the multiple insecticide resistant strain ALHF (wild-type) and two insecticide susceptible strains: aabys (with morphological recessive markers) and CS (wild type) to gain valuable insights into the gene interaction and complex regulation in insecticide resistance of house flies, Musca domestica. Results Over 56 million reads were used to assemble the adult female M. domestica transcriptome reference and 14488 contigs were generated from the de novo transcriptome assembly. A total of 6159 (43%) of the contigs contained coding regions, among which 1316 genes were identified as being co-up-regulated in ALHF in comparison to both aabys and CS. The majority of these up-regulated genes fell within the SCOP categories of metabolism, general, intra-cellular processes, and regulation, and covered three key detailed function categories: redox detailed function category in metabolism, signal transduction and kinases/phosphatases in regulation, and proteases in intra-cellular processes. The redox group contained detoxification gene superfamilies, including cytochrome P450s, glutathione S-transferases, and esterases. The signal transduction and kinases/phosphatases groups contained gene families of rhodopsin-like GPCRs, adenylate and guanylate cyclases, protein kinases and phosphatases. The proteases group contained genes with digestive, catalytic, and proteinase activities. Genetic linkage analysis with house fly lines comparing different autosomal combinations from ALHF revealed that the up-regulation of gene expression in the three key SCOP detailed function categories occurred mainly through the co-regulation of factors among multiple autosomes, especially between autosomes 2 and 5, suggesting that signaling transduction cascades controlled by GPCRs, protein kinase/phosphates and proteases may be involved in the regulation of resistance P450 gene regulation. Conclusion Taken together, our findings suggested that not only is insecticide resistance conferred via multi-resistance mechanisms or up-regulated genes, but it is mediated through the trans and/or cis co-regulations of resistance genes. [ABSTRACT FROM AUTHOR]

The mosquito vector Aedes aegypti transmits arthropod-borne viruses (arboviruses) of medical importance, including Zika, dengue, and yellow fever viruses. Controlling mosquito populations remains the method of choice to prevent disease transmission. Novel mosquito control strategies based on genetically manipulating mosquitoes are being developed as additional tools to combat arbovirus transmission. Genetic control of mosquitoes includes two basic strategies: population suppression and population replacement. The former aims to eliminate mosquito populations while the latter aims to replace wild populations with engineered, pathogen-resistant mosquitoes. In this review, we outline suppression strategies being applied in the field, as well as current antiviral effector genes that have been characterized and expressed in transgenic Ae. aegypti for population replacement. We discuss cutting-edge gene drive technologies that can be used to enhance the inheritance of effector genes, while highlighting the challenges and opportunities associated with gene drives. Finally, we present currently available models that can estimate mosquito release numbers and time to transgene fixation for several gene drive systems. Based on the recent advances in genetic engineering, we anticipate that antiviral transgenic Ae. aegypti exhibiting gene drive will soon emerge; however, close monitoring in simulated field conditions will be required to demonstrate the efficacy and utility of such transgenic mosquitoes. [ABSTRACT FROM AUTHOR]

The article reports on the sponsorship of a network of regional special education instructional materials centers by the U.S. Office of Education through its Bureau of Handicapped Children and Youth. Each of the centers is geographically located to serve special education teachers. The centers were focused on one or more areas of exceptionality. The Rocky Mountain Special Education Instructional Materials Center in Colorado has assumed responsibility for exceptional areas such as the areas of the deaf and hard of hearing. Their services covered five states.