Screening of olfactory genes related to blood-feeding behaviors in Culex pipiens quinquefasciatus and Culex pipiens molestus by transcriptome analysis.

BACKGROUND: Culex pipiens quinquefasciatus Say (Cx. quinquefasciatus) and Culex pipiens form molestus Forskal (Cx. molestus) in the Culex pipiens complex group show considerable differences in host seeking, blood feeding, mating behavior and in vector competence. Blood-feeding mosquito behaviors are closely related to their olfactory gene expression and olfactory gene repertoire composition. Comparing olfactory genes between these two subspecies with significantly different blood-feeding behaviors can support further research on the molecular mechanism of the Culex pipiens complex olfactory sensory system, providing a new approach for determining candidate attractant or repellent compounds. METHODS: Non-blood-feeding (NBF) and post-blood-feeding (PBF) olfactory system transcriptomes of the two subspecies were sequenced, and the biological functions of their differentially expressed genes were described by bioinformatics analysis. A quantitative polymerase chain reaction (qPCR) was applied to validate the RNA-seq data. The roles of particular olfactory receptors in Cx. quinquefasciatus blood-feeding behaviors were evaluated by RNAi. RESULTS: Five, 7, 24, and 3 Cx. quinquefasciatus-specific OBPs, Cx. molestus-specific OBPs, Cx. quinquefasciatus-specific ORs and Cx. molestus-specific ORs were identified, respectively. The majority of selected ORs were consistent with the predicted transcriptome sequencing results after qRT-PCR validation. OR5 was expressed only in Cx. quinquefasciatus, and OR65 was the only gene upregulated after blood feeding in Cx. molestus. The blood-feeding rates of the OR5 and OR78 dsRNA groups were significantly lower (4.3%±3.1% and 13.3%±11.5%) than those of the enhanced green fluorescence protein (EGFP) group (64.5%±8.7%). CONCLUSION: Most OBPs and ORs were expressed in both subspecies but showed divergence in expression level. OR5 and OR65 might be species-specific expressed genes that regulate the olfactory behaviors of Cx. quinquefasciatus and Cx. molestus, respectively. The RNA interference of OR5 and OR78 could inhibit the blood-feeding behavior of Cx. quinquefasciatus, providing new targets for screening effective repellent compounds to control mosquito-borne diseases effectively and efficiently.

Transcriptome analysis of Aedes aegypti Aag2 cells in response to dengue virus-2 infection.

BACKGROUND: Dengue virus (DENV) is a flavivirus transmitted by mosquitoes that is prevalent in tropical and subtropical countries and has four serotypes (DENV1-4). Aedes aegypti, as the main transmission vector of DENV, exhibits strong infectivity and transmission. With the aim of obtaining a better understanding of the Ae. aegypti-DENV interaction, the transcriptome changes in DENV-2-infected Aag2 cells were studied to describe the immune responses of mosquitoes using the Ae. aegypti Aag2 cell line as a model. METHODS: RNAseq technology was used to sequence the transcripts of the Ae. aegypti Aag2 cell line before and after infection with DENV-2. A bioinformatics analysis was then performed to assess the biological functions of the differentially expressed genes, and the sequencing data were verified by quantitative reverse transcription-polymerase chain reaction (qRT-PCR). RESULTS: The transcriptome analysis generated 8866 unigenes that were found in both groups, 225 unigenes that were only found in the infection group, and 683 unigenes that only existed in the control group. A total of 1199 differentially expressed genes, including 1014 upregulated and 185 downregulated genes, were identified. The bioinformatics analysis showed that the differentially expressed genes were mainly involved in the longevity regulating pathway, circadian rhythm, DNA replication, and peroxisome, purine, pyrimidine, and drug metabolism. The qRT-PCR verification results showed the same trend, which confirmed that the expression of the differentially expressed genes had changed, and that the transcriptome sequencing data were reliable. CONCLUSIONS: This study investigated the changes in the transcriptome levels in the DENV-2-infected Ae. aegypti Aag2 cell line, which provides a faster and effective method for discovering genes related to Ae. aegypti pathogen susceptibility. The findings provide basic data and directions for further research on the complex mechanism underlying host-pathogen interactions.

[Pollution Characteristics and Emission Coefficients of Volatile Organic Compounds from the Packaging and Printing Industry in Zhejiang Province].

This paper presents the raw material composition and VOC treatment status of the packaging and printing industry in Zhejiang Province based on the survey data obtained in 2015 of 254 packaging and printing enterprises. To analyze the emission characteristics and calculate the emission coefficients of the packaging and printing industry, 100 typical enterprises were further screened according to different printing processes. The results showed that about two-thirds of packaging and printing enterprises failed to effectively dispose of VOCs; meanwhile, solvent-based materials were still commonly used in the packaging and printing industry. The main emission pollution factors of VOCs in the packaging and printing industry were ethyl acetate, isopropanol, ethanol, propyl acetate, and n-butyl acetate. The VOC emission coefficient of the packaging and printing industry in Zhejiang Province was 0.485 kg·kg-1, of which the gravure printing was the primary source with VOCs emission coefficient of 0.634 kg·kg-1. Compared with the material balance method, the error value from the emission coefficient method was less than 15%.

[Pollution Characteristics and Emission Coefficient of Volatile Organic Compounds from Woodwork-making Industry in Zhejiang Province].

To explore the pollution characteristics and emission coefficient of volatile organic compound (VOCs) released from the woodwork-making industry in Zhejiang province, this paper used the survey data of 310 woodwork enterprises obtained in 2015 to analyze the current VOCs treatment status of woodwork-making industry, and further screened 213 key enterprises to study the emission coefficient of woodwork-making industry. The results showed that more than 94% of woodwork enterprises failed to effectively dispose VOCs since most woodwork enterprises did not have treatment facilities. Moreover, solvent-based materials such as adhesive and paint were still commonly used in woodwork-making industry. Meanwhile, the main pollutants of VOCs in woodwork-making industry were dimethyl benzene, butyl acetate, ethyl acetate, toluene and formaldehyde. Furthermore, the VOCs emission coefficient of woodwork-making industry in Zhejiang was 93.4 g·(million Yuan)-1, while it was affected by the production processes, and the VOCs emission coefficient of enterprises using the coating techniques was higher than that using the adhesive techniques, being 93.6 g·(million Yuan)-1 and 9.5 g·(million Yuan)-1, respectively. Furthermore, the major polluting stage of woodwork-making industry was coating stage, and the VOCs emission coefficient was 31.0 g·(million Yuan)-1 when waterborne and UV coating was used. The highest VOCs emission coefficient was from wooden furniture manufacturers, which could reach 168.5 g·(million Yuan)-1 when solvent-based coatings were used.

[Preparation of bovine lipid-free hemoglobin].

A new method for preparation of Hb solution free of stromal lipid was described. Almost all the lipid in fresh hemolysate of bovine red blood was removed with hydrophobic interaction chromatography (HIC) in the presence of 2% PEG4000, 5% PEG4000, 2%PEG10000 or 5%PEG10000. With the adding of 5%PEG4000, the 80% of recovery of Hb in HIC was obtained and the maximum lipid absorbed by hydrophobic medium, butyl agarose -6B was 86.6 mg/mL. The activity (P50) of hemoglobin preparation was 3386.4 Pa torrs, and the Hill number was 2.54, which were near to that of the native red blood cells. The mechanism of removing lipid by HIC and the function of PEG in the process were discussed.