BackgroundAdult house flies, Musca domestica L., are mechanical vectors of more than 100 devastating diseases that have severe consequences for human and animal health. House fly larvae play a vital role as decomposers of animal wastes, and thus live in intimate association with many animal pathogens.ResultsWe have sequenced and analyzed the genome of the house fly using DNA from female flies. The sequenced genome is 691 Mb. Compared with Drosophila melanogaster, the genome contains a rich resource of shared and novel protein coding genes, a significantly higher amount of repetitive elements, and substantial increases in copy number and diversity of both the recognition and effector components of the immune system, consistent with life in a pathogen-rich environment. There are 146 P450 genes, plus 11 pseudogenes, in M. domestica, representing a significant increase relative to D. melanogaster and suggesting the presence of enhanced detoxification in house flies. Relative to D. melanogaster, M. domestica has also evolved an expanded repertoire of chemoreceptors and odorant binding proteins, many associated with gustation.ConclusionsThis represents the first genome sequence of an insect that lives in intimate association with abundant animal pathogens. The house fly genome provides a rich resource for enabling work on innovative methods of insect control, for understanding the mechanisms of insecticide resistance, genetic adaptation to high pathogen loads, and for exploring the basic biology of this important pest. The genome of this species will also serve as a close out-group to Drosophila in comparative genomic studies.Electronic supplementary materialThe online version of this article (doi:10.1186/s13059-014-0466-3) contains supplementary material, which is available to authorized users.

Four cytochrome P450 cDNAs, CYP6AA7, CYP9J40, CYP9J34, and CYP9M10, were isolated from mosquitoes, Culex quinquefasciatus. The P450 gene expression and induction by permethrin were compared for three different mosquito populations bearing different resistance phenotypes, ranging from susceptible (S-Lab), through intermediate (HAmCqG0, the field parental population) to highly resistant (HAmCqG8, the 8th generation of permethrin selected offspring of HAmCqG0). A strong correlation was found for P450 gene expression with the levels of resistance and following permethrin selection at the larval stage of mosquitoes, with the highest expression levels identified in HAmCqG8, suggesting the importance of CYP6AA7, CYP9J40, CYP9J34, and CYP9M10 in the permethrin resistance of larva mosquitoes. Only CYP6AA7 showed a significant overexpression in HAmCqG8 adult mosquitoes. Other P450 genes had similar expression levels among the mosquito populations tested, suggesting different P450 genes may be involved in the response to insecticide pressure in different developmental stages. The expression of CYP6AA7, CYP9J34, and CYP9M10 was further induced by permethrin in resistant mosquitoes. Taken together, these results indicate that multiple P450 genes are up-regulated in insecticide resistant mosquitoes through both constitutive overexpression and induction mechanisms, thus increasing the overall expression levels of P450 genes.

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.

To gain valuable insights into the gene interaction and the complex regulation system involved in the development of insecticide resistance in mosquitoes Culex quinquefasciatus, we conducted a whole transcriptome analysis of Culex mosquitoes following permethrin selection. Gene expression profiles for the lower resistant parental mosquito strain HAmCqG0 and their permethrin-selected high resistant offspring HAmCqG8 were compared and a total of 367 and 3982 genes were found to be up- and down-regulated, respectively, in HAmCqG8, indicating that multiple genes are involved in response to permethrin selection. However, a similar overall cumulative gene expression abundance was identified between up- and down-regulated genes in HAmCqG8 mosquitoes following permethrin selection, suggesting a homeostatic response to insecticides through a balancing of the up- and down-regulation of the genes. While structural and/or cuticular structural functions were the only two enriched GO terms for down-regulated genes, the enriched GO terms obtained for the up-regulated genes occurred primarily among the catalytic and metabolic functions where they represented three functional categories: electron carrier activity, binding, and catalytic activity. Interestingly, the functional GO terms in these three functional categories were overwhelmingly overrepresented in P450s and proteases/serine proteases. The important role played by P450s in the development of insecticide resistance has been extensively studied but the function of proteases/serine proteases in resistance is less well understood. Hence, the characterization of the functions of these proteins, including their digestive, catalytic and proteinase activities; regulation of signaling transduction and protein trafficking, immunity and storage; and their precise function in the development of insecticide resistance in mosquitoes will provide new insights into how genes are interconnected and regulated in resistance.

Insect genome editing was first reported 1991 in Drosophila melanogaster but the technology used was not portable to other species. Not until the recent development of facile, engineered DNA endonuclease systems has gene editing become widely available to insect scientists. Most applications in insects to date have been technical in nature but this is rapidly changing. Functional genomics and genetics-based insect control efforts will be major beneficiaries of the application of contemporary gene editing technologies. Engineered endonucleases like Cas9 make it possible to create powerful and effective gene drive systems that could be used to reduce or even eradicate specific insect populations. 'Best practices' for using Cas9-based editing are beginning to emerge making it easier and more effective to design and use but gene editing technologies still require traditional means of delivery in order to introduce them into somatic and germ cells of insects-microinjection of developing embryos. This constrains the use of these technologies by insect scientists. Insects created using editing technologies challenge existing governmental regulatory structures designed to manage genetically modified organisms.

A preclinical method for the evaluation of antibacterial agents for use against dental plaques associated with caries and periodontal disease is proposed. The method is applicable to screening agents and to defining, in vitro, the minimal conditions required for maximal antiplaque effect. As a model of antiplaque agents, chlorhexidine was assessed in vitro against preformed plaques of microorganisms conducive to dental caries and periodontal disease. The agent was bactericidal to plaques of nine strains of Streptococcus mutans and one strain of Actinomyces viscosus when used in a single treatment for 20 min at 2 x 10(-1)%, in two 2-min treatments on the same day, or in daily 2-min treatments at this same concentration. Using the last of these experimental conditions, we then tested chlorhexidine in vivo by topical application to the maxillary teeth of infected hamsters and found it to be effective in controlling plaques of S. mutans and A. viscosus.

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Prior to acquisition of the first host blood meal, the anautogenous mosquito Culex quinquefasciatus requires a period of time in order to prepare for the blood feeding and, later, vitellogenesis. In the current study, we conducted whole transcriptome analyses of adult female Culex mosquitoes to identify genes that may be necessary for both taking of the blood meal, and processing of the blood meal in adult female mosquitoes Cx. quinquefasciatus. We examined temporal expression of genes for the periods of post eclosion and prior to the female freely taking a blood meal. We further evaluated the temporal expression of certain genes for the periods after the taking of a blood meal to identify genes that may be necessary for both the taking of the blood meal, and the processing of the blood meal. We found that adult females required a minimum of 48 h post-eclosion before they freely took their first blood meal. We hypothesized that gene expression signatures were altered in the mosquitoes before blood feeding in preparation for the acquisition of the blood meal through changes in multiple gene expression. To identify the genes involved in the acquisition of blood feeding, we quantified the gene expression levels of adult female Cx. quinquefasciatus using RNA Seq throughout a pre-blooding period from 2 to 72 h post eclosion at 12 h intervals. A total of 325 genes were determined to be differentially-expressed throughout the pre-blooding period, with the majority of differentially-expressed genes occurring between the 2 h and 12 h post-eclosion time points. Among the up-regulated genes were salivary proteins, cytochrome P450s, odorant-binding proteins, and proteases, while the majority of the down-regulated genes were hypothetical or cuticular genes. In addition, Trypsin was found to be up-regulated immediately following blood feeding, while trypsin and chymotrypsin were up-regulated at 48h and 60h post blood-feeding, respectively, suggesting that these proteases are likely involved in the digestion of the blood meal. Overall, this study reviewed multiple genes that might be involved in the adult female competency for blood meal acquisition in mosquitoes.