AANAT1 regulates insect midgut detoxification through the ROS/CncC pathway.

Insecticide resistance has been a problem in both the agricultural pests and vectors. Revealing the detoxification mechanisms may help to better manage insect pests. Here, we showed that arylalkylamine N-acetyltransferase 1 (AANAT1) regulates intestinal detoxification process through modulation of reactive oxygen species (ROS)-activated transcription factors cap"n"collar isoform-C (CncC): muscle aponeurosis fibromatosis (Maf) pathway in both the oriental fruit fly, Bactrocera dorsalis, and the arbovirus vector, Aedes aegypti. Knockout/knockdown of AANAT1 led to accumulation of biogenic amines, which induced a decreased in the gut ROS level. The reduced midgut ROS levels resulted in decreased expression of CncC and Maf, leading to lower expression level of detoxification genes. AANAT1 knockout/knockdown insects were more susceptible to insecticide treatments. Our study reveals that normal functionality of AANAT1 is important for the regulation of gut detoxification pathways, providing insights into the mechanism underlying the gut defense against xenobiotics in metazoans.

Gut Microbiome Composition of the Fire Ant Solenopsis invicta: an Integrated Analysis of Host Genotype and Geographical Distribution.

Gut symbiotic bacteria are known to be closely related to insect development, nutrient metabolism, and disease resistance traits, but the most important factors leading to changes in these communities have not been well clarified. To address this, we examined the associations between the gut symbiotic bacteria and the host genotype and geographical distribution of Solenopsis invicta in China, where it is invasive and has spread primarily by human-mediated dispersal. Thirty-two phyla were detected in the gut symbiotic bacteria of S. invicta. Proteobacteria were the most dominant group among the gut symbiotic bacteria. Furthermore, the Bray-Curtis dissimilarity matrices of the gut symbiotic bacteria were significantly positively correlated with the geographical distance between the host ant colonies, but this relationship was affected by the social form. The distance between monogyne colonies had a significant effect on the Bray-Curtis dissimilarity matrices of gut symbiotic bacteria, but the distance between polygyne colonies did not. Moreover, the Bray-Curtis dissimilarity matrices were positively correlated with Nei's genetic distance of the host but were not correlated with the COI-based genetic distance. This study provides a scientific basis for further understanding the ecological adaptability of red imported fire ants during invasion and dispersal. IMPORTANCE We demonstrated that gut microbiota composition and diversity varied among populations. These among-population differences were associated with host genotype and geographical distribution. Our results suggested that population-level differences in S. invicta gut microbiota may depend more on environmental factors than on host genotype.

[In vivo study of Chuankezhi metabolism in rat].

To study the metabolic products of main compounds of Chuankezhi injection in rat, 12 Sprague Dawley rats were classed into 2 groups, a blank control group and an intermuscular administration group, respectively. Rat feces and urine samples were collected from 0−24 h and 24−48 h after administration. All the samples were ultrasonically treated with methanol and then analyzed using LC-LTQ Orbitrap MSn. By comparison with the total ion chromatogram of samples from the blank control group, the metabolites in the samples of drug-treated group were screened. These metabolites were further analyzed by multistage product ion scanning and comparison of retention time with reference substances. As a result, a total of 12 flavonoid metabolites were tentatively identified from the rat feces and no metabolite was discovered in the rat urine. Epimedin C and icariin were detected in the rat blood samples after 30 min of administration, but their metabolites and other original flavones were not detected. Furthermore, no original flavones and their metabolites were detected in rat blood samples after 2 and 4 h of administration. The potential metabolism paths were further characterized and the principal in vivo transformation of flavones from Chuankezhi injection were deglycosylation, dehydration, methylation, oxidation and isomerization in rats.

[Simultaneous determination of 4 prenylflavonoids of Chuankezhi injection in rat plasma by LC-MS/MS].

A quantitative method for epimedin A, B, C and icariin in rat plasma was established using LC-MS/MS after intermuscular administration of Chuankezhi injection to rat. Chromatographic separation was performed on an Agilent Eclipse XDB-C(18) column (150 mm × 2.1 mm, 5.0 µm) at 40 ℃. Mobile phase consisted of acetonitrile-0.1% formic acid in water（35∶65）, and the flow rate was 0.22 m L·min(-1). The LC effluent was detected and analyzed using an ESI-triple quadrupole tandem mass spectrometer under the multiple reaction monitoring (MRM) in the negative ion mode. The plasma samples were treated with solid phase extraction prior to LC-MS/MS analysis. As a result, all of the four analytes displayed a good linearity over the concentration of 1-1 000 ng·mL(-1). The RSDs of intra-day and inter-day assays were less than 5.99% and 10.16%, respectively. The relative recovery of each analyte was between 88.1%-101.1% with RSD < 7.9% and the absolute recovery was between 72.0%-86.6%（RSD < 6.3%）. In conclusion, the established method shows good specificity, sensitivity and efficiency for quantifying the four flavonoid glycosides contained in rat plasma.

[Pharmacokinetics of epimedin A, B, C and icariin of Chuankezhi injection in rat].

To study pharmacokinetic characteristics of epimedin A, B, C and icariin after intermuscular administration of Chuankezhi injection to rat. The established RRLC-MS/MS method was applied for simultaneous determination of four analytes in rat plasma and calculating their pharmacokinetic parameters. As a result, each analyte showed a good linear relationship in the concentration range of 1-1 000 µg•L⁻¹.The intra-day precise was 96.9%-107.5% with RSD<5.99%, inter-day precise was 92.3%-105.0% with RSD<10.16%. The relative recovery of four analytes was 88.1%-101.1% with RSD<7.9% and their absolute recovery was 72.0%-86.6% with RSD<6.3%. After intermuscular administration of Chuankezhi injection, the plasma concentration of four flavonoid glycosides rapidly arose to peaks at about 10 min, and then quickly declined in rat. Tmax of epimedin A, B, C and icariin was 0.21, 0.19, 0.16 and 0.49 h, respectively, and their mean elimination half-life(t1/2z) was 0.60, 0.62, 0.47 and 0.49 h. The established method was validated to be sensitive, rapid and specific for determination of the four analytes. Serum concentration of 4 species of epimedium flavonoids in Chuankezhi injection was low, and their absorption and elimination seem quickly, displaying similar pharmacokinetic characteristics in this study.

[Relationships between mound size and captured ergate amount of Solenopsis invicta].

By the method of bait trapping, this paper studied the relationships between mound size (mound volume and mound surface base area) and captured ergate amount of Solenopsis invicta in wasteland and greenbelt. In wasteland, with the increase of mound size, the amount of captured S. invicta ergates increased rapidly at first, slowed down then, and kept stable at last. When the mound volume and surface base area were 11634 cm3 and 1308 cm2 respectively, the captured ergate amount reached the maximum, being 291 individuals per trap. Similar patterns were observed in greenbelt. The increase of captured S. invicta ergate amount slowed down rapidly when the mound volume was larger than 18089 cm3, and reached the maximum (232 individual per trap) when the mound volume was 25974 cm3. The Weibull equation could better describe the relationships between the mound volume and mound surface base area and the captured ergate amount of S. invicta.