Mesoporous silica nanospheres-mediated insecticide and antibiotics co-delivery system for synergizing insecticidal toxicity and reducing environmental risk of insecticide.

Mesoporous silica nanoparticles (MSNs) are efficient carriers of drugs, and are promising in developing novel pesticide formulations. The cotton aphids Aphis gossypii Glover is a world devastating insect pest. It has evolved high level resistance to various insecticides thus resulted in the application of higher doses of insecticides, which raised environmental risk. In this study, the MSNs based pesticide/antibiotic delivery system was constructed for co-delivery of ampicillin (Amp) and imidacloprid (IMI). The IMI@Amp@MSNs complexes have improved toxicity against cotton aphids, and reduced acute toxicity to zebrafish. From the 16S rDNA sequencing results, Amp@MSNs, prepared by loading ampicillin to the mesoporous of MSNs, greatly disturbed the gut community of cotton aphids. Then, the relative expression of at least 25 cytochrome P450 genes of A. gossypii was significantly suppressed, including CYP6CY19 and CYP6CY22, which were found to be associated with imidacloprid resistance by RNAi. The bioassay results indicated that the synergy ratio of ampicillin to imidacloprid was 1.6, while Amp@MSNs improved the toxicity of imidacloprid by 2.4-fold. In addition, IMI@Amp@MSNs significantly improved the penetration of imidacloprid, and contributed to the amount of imidacloprid delivered to A. gossypii increased 1.4-fold. Thus, through inhibiting the relative expression of cytochrome P450 genes and improving penetration of imidacloprid, the toxicity of IMI@Amp@MSNs was 6.0-fold higher than that of imidacloprid. The greenhouse experiments further demonstrated the enhanced insecticidal activity of IMI@Amp@MSNs to A. gossypii. Meanwhile, the LC50 of IMI@Amp@MSNs to zebrafish was 3.9-fold higher than that of IMI, and the EC50 for malformation was 2.8-fold higher than IMI, respectively, which indicated that the IMI@Amp@MSNs complexes significantly reduced the environmental risk of imidacloprid. These findings encouraged the development of pesticide/antibiotic co-delivery nanoparticles, which would benefit pesticide reduction and environmental safety.

The gut symbiont Sphingomonas mediates imidacloprid resistance in the important agricultural insect pest Aphis gossypii Glover.

BACKGROUND: Neonicotinoid insecticides are applied worldwide for the control of agricultural insect pests. The evolution of neonicotinoid resistance has led to the failure of pest control in the field. The enhanced detoxifying enzyme activity and target mutations play important roles in the resistance of insects to neonicotinoid resistance. Emerging evidence indicates a central role of the gut symbiont in insect pest resistance to pesticides. Existing reports suggest that symbiotic microorganisms could mediate pesticide resistance by degrading pesticides in insect pests. RESULTS: The 16S rDNA sequencing results showed that the richness and diversity of the gut community between the imidacloprid-resistant (IMI-R) and imidacloprid-susceptible (IMI-S) strains of the cotton aphid Aphis gossypii showed no significant difference, while the abundance of the gut symbiont Sphingomonas was significantly higher in the IMI-R strain. Antibiotic treatment deprived Sphingomonas of the gut, followed by an increase in susceptibility to imidacloprid in the IMI-R strain. The susceptibility of the IMI-S strain to imidacloprid was significantly decreased as expected after supplementation with Sphingomonas. In addition, the imidacloprid susceptibility in nine field populations, which were all infected with Sphingomonas, increased to different degrees after treatment with antibiotics. Then, we demonstrated that Sphingomonas isolated from the gut of the IMI-R strain could subsist only with imidacloprid as a carbon source. The metabolic efficiency of imidacloprid by Sphingomonas reached 56% by HPLC detection. This further proved that Sphingomonas could mediate A. gossypii resistance to imidacloprid by hydroxylation and nitroreduction. CONCLUSIONS: Our findings suggest that the gut symbiont Sphingomonas, with detoxification properties, could offer an opportunity for insect pests to metabolize imidacloprid. These findings enriched our knowledge of mechanisms of insecticide resistance and provided new symbiont-based strategies for control of insecticide-resistant insect pests with high Sphingomonas abundance.

The influence of Bt cotton cultivation on the structure and functions of the soil bacterial community by soil metagenomics.

Bt cotton successfully controlled major devastating pests in cotton，such as Helicoverpa armigera and Spodoptera exigua, and led to a drastic decrease in insecticide use in cotton fields, and it has been grown commercially worldwide. However, Bt cotton cultivation left Bt toxin residues in the soil, resulting in a response by its microbiome that caused potential environmental risks. In this research, the metagenomics analysis was performed to investigate the structure and functions of the soil bacterial community in the Bt cotton field from the Binzhou, Shandong province of China, where the Bt cotton has been cultivated for over fifteen years. Analysis of the function genes proved that the receptors of Bt toxins were absent in the soil bacteria and Bt toxins failed to target the soil bacteria. The microbiome structure and function were highly influenced by Bt cotton cultivation, however, no significant change in the total abundance of the bacteria was observed. Proteobacteria was the largest taxonomic group in the soil bacterial (42-52%) and its abundance was significantly increased after Bt cotton cultivation. The increase of Proteobacteria abundance resulted in an increase in ABC transporters gene abundance, indicating the improved ability of detoxification metabolism over Bt cotton cultivation. Xanthomonadales could be a biomarker of the Bt cotton group, whose abundance was significantly increased to contribute to the increase of the genes abundance in ABC transporters. The abundance of apoptosis genes was significantly decreased, and it might be related to the increase of Proteobacteria abundance by Bt cotton cultivation. In addition, Myxococcales was responsible for carotenoid biosynthesis, whoes genes abundance was significantly decreased due to the decrease of Myxococcales abundance by Bt cotton cultivation. These changes in soil bacterial community structure and functions indicate the influence by Bt cotton cultivation, leading to an understanding of the bacteria colonization patterns due to successive years of Bt cotton cultivation. These research results should be significant for the rational risk assessment of Bt cotton cultivation.

The Expression of Transcription Factors is Different in Papillary Thyroid Cancer Cells during TNF - α induced EMT.

Proinflammatory factor tumor necrosis factor-α (TNF-α) is an important inflammatory mediators in tumor microenvironment and autoimmune diseases, it is highly expressed in many solid tumors and tumor microenvironment, showing a tumor promoting role. However, the molecular mechanisms underlying TNF-α-increased invasion of thyroid cancer are still not fully understood. In order to explore whether TNF-α plays a key role in the process of epithelial mesenchymal transition (EMT) in papillary thyroid carcinoma (PTC), we used TNF-α to induce EMT in different PTC cell lines, and observed the expression of different transcription factors and signal pathways. After TNF-α treatment, in TPC-1, Snail and ZEB2 mRNA levels did not change significantly, while Slug, Twist1, ZEB1 mRNA expression increased. In BCPAP, Snail mRNA level increased significantly (P < 0.01), while Twist1 showed a certain degree of increase only at the concentration of TNF - α 20 ng / ml (P < 0.01), but mRNA of Slug, ZEB1, ZEB2 showed no significant change. The expression of proteins was consistent with genes. The activation of different pathways did not show gene differences, and pathway inhibitors could reduce the invasion and metastasis of cells, but only NF-κB inhibitors could reverse the expression of transcription factors. Expressions of Snail and Slug in different PTC cell lines were dependent on pro-oncogene mutation, but the pathway had no differences. The establishment of this study model can enrich the research on the pathogenesis and metastasis of thyroid cancer, effectively link the inflammatory microenvironment with the occurrence and development of thyroid cancer.

Sublethal and lethal effects of the imidacloprid on the metabolic characteristics based on high-throughput non-targeted metabolomics in Aphis gossypii Glover.

Sublethal effect considered as an emerging factor to assess the environmental risk of insecticides, which can impact the insects on both physiology and behavior. Lethal exposure can be causing near immediate mortality. Pests are inevitably exposed to sublethal and lethal dose in the agroecosystem following application of pesticides. Insecticides, widely used for the control of insect pests, are irreplaceable in insect pest management. The effects of imidacloprid by the method of high-throughput non-targeted metabolomics was investigated in Aphis gossypii Glover exposed to LC10 and LC90 doses of the imidacloprid, and the control group was treated with the same condition without imidacloprid. Pairwise comparisons showed that 111 metabolites changed significantly, 60 in the LC10 group, and 66 in the LC90 group compared to the control group, while only 16 changes in the LC10 were same with that in LC90 group. Among the changed metabolites, a total of 16 metabolites were identified as potential biomarkers, which represented the most influential pathways including glycolysis and gluconeogenesis, alanine, aspartate, and glutamate metabolism, ascorbate and aldarate metabolism, glutathione metabolism, phenylalanine metabolism, tyrosine metabolism, caffeine metabolism and parkinson's disease (PD), which could account for the sublethal and lethal effects on A. gossypii. These modified metabolic pathways demonstrated that high energy consumption, excitotoxicity and oxidative stress (OS) were appeared in both LC10 and LC90 groups, while PD was detected only in the LC90 group. The results of non-targeted metabolomics revealed the effects of neonicotinoid pesticide exposure on A. gossypii successfully, and provided a deep insight into the influenced physiology by the stress of neonicotinoid pesticide in the insect.

Fitness costs of sulfoxaflor resistance in the cotton aphid, Aphis gossypii Glover.

Aphis gossypii Glover is an economically important pest of numerous crops throughout the world. Some field populations of A.gossypii in China have developed moderate level of resistance to sulfoxaflor, a newly released sulfoximine insecticide for management of sap-feeding pests. To evaluate the effect of sulfoxaflor resistance on the fitness cost of A. gossypii, the life history traits of sulfoxaflor-resistant strain (SulR) and an isogenic susceptible strain (SS) were compared using the age-stage, two-sex life table approach. The results showed that the resistant strain had a reduction in fitness (relative fitness = 0.917), along with significantly decreases in longevity, fecundity, net reproductive (R0), mean generation time (T) and gross reproductive rate (GRR). Compared to the susceptible strain, SulR strain showing a shorter developmental duration of each nymph instar stage. Moreover, the adult pre-oviposition period (APOP) and total preoviposition period (TPOP) of SulR strain were also significantly shorter than that of the susceptible strain. Investigation of six development and reproduction related genes indicated that EcR, USP and JHBP were overexpressed in the SulR strain, while the mRNA transcript level of Vg was decreased significantly compared to the susceptible strain. These results suggest that there is a fitness cost associated with sulfoxaflor resistance in A. gossypii and the different expression of EcR, USP, JHBP, and Vg may play very important role in this trade-off.

Reproductive adaptation in alate adult morphs of the English grain aphid Sitobion avenae under starvation stress.

Adapting their reproductive physiology is a tactic that insects use in responding to conditions of food unavailability. The present study examined the potential effects of starvation periods on the ovarian development and reproduction of alate adult morphs of Sitobion avenae (Fabricius). Morphs both continuously fed and starved aphids contained two telotrophic ovaries, each comprising five ovarioles. As time increase after emergence, the number of offspring produced by the fed aphids increased gradually, whereas the number of embryos in their ovaries decreased gradually. Both the number of mature embryos and the volume of embryos rapidly increased at 24 h after emergence, and then remained at an approximately constant level between 24 and 144 h. Compared to the fed aphids, starved aphids only produced a small number of nymphs, and there was no significant change in the total number of embryos between 24 and 144 h, whereas both the number of mature embryos and volume of embryos increased significantly. Irrespective of starvation period, highly significant relationships between life span and fecundity were found. Adult aphids starved for longer periods presented lower longevity and fecundity, but dead females contained more mature embryos than those starved for shorter periods. These results suggested that, under starvation stress, S. avenae tends to invest in the development of larger embryos at the expense of reducing lifespan and future fecundity. This adaptive reproductive strategy under starvation stress could be one of the factors contributing to the successful establishment of new colonies of alate migratory aphids.

Knockdown of SETDB1 inhibits breast cancer progression by miR-381-3p-related regulation.

BACKGROUND: SET domain bifurcated 1 (SETDB1) has been widely considered as an oncogene playing a critical role in many human cancers, including breast cancer. Nevertheless, the molecular mechanism by which SETDB1 regulates breast cancer tumorigenesis is still unknown. METHODS: qRT-PCR assay or western blot analysis was performed to assess the expression level of SETDB1 mRNA or protein, respectively. siSETDB1, pCMV6-XL5-SETDB1, miR-381-3p mimic, or miR-381-3p inhibitor was transfected into cells to regulate the expression of SETDB1 or miR-381-3p. MiRNA directly interacted with SETDB1 was verified by luciferase reporter assay and RNA immunoprecipitation. CCK-8 assay, colony formation assay, flow cytometric analysis, and transwell assay were used to detect the abilities of cell proliferation, cell cycle progression and migration, respectively. Animal model of xenograft tumor was used to observe the regulatory effect of SETDB1 on tumor growth in vivo. RESULTS: We verified that SETDB1 mRNA level was upregulated in breast cancer tissues and cell lines, and SETDB1 depletion led to a suppression of cell proliferation, cell cycle progression and migration in vitro, as well as tumor growth in vivo. SETDB1 was verified to be a target of miR-381-3p. Moreover, miR-381-3p overexpression suppressed cell proliferation, cell cycle progression and migration, whereas SETDB1 abated miR-381-3p-mediated regulatory function on breast cancer cells. CONCLUSIONS: This study revealed that SETDB1 knockdown might suppress breast cancer progression at least partly by miR-381-3p-related regulation, providing a novel prospect in breast cancer therapy.

Knockdown of SETDB1 inhibits breast cancer progression by miR-381-3p-related regulation

BACKGROUND: SET domain bifurcated 1 (SETDB1) has been widely considered as an oncogene playing a critical role in many human cancers, including breast cancer. Nevertheless, the molecular mechanism by which SETDB1 regulates breast cancer tumorigenesis is still unknown. METHODS: qRT-PCR assay or western blot analysis was performed to assess the expression level of SETDB1 mRNA or protein, respectively. siSETDB1, pCMV6-XL5-SETDB1, miR-381-3p mimic, or miR-381-3p inhibitor was transfected into cells to regulate the expression of SETDB1 or miR-381-3p. MiRNA directly interacted with SETDB1 was verified by luciferase reporter assay and RNA immunoprecipitation. CCK-8 assay, colony formation assay, flow cytometric analysis, and transwell assay were used to detect the abilities of cell proliferation, cell cycle progression and migration, respectively. Animal model of xenograft tumor was used to observe the regulatory effect of SETDB1 on tumor growth in vivo. RESULTS: We verified that SETDB1 mRNA level was upregulated in breast cancer tissues and cell lines, and SETDB1 depletion led to a suppression of cell proliferation, cell cycle progression and migration in vitro, as well as tumor growth in vivo. SETDB1 was verified to be a target of miR-381-3p. Moreover, miR-381-3p overexpression suppressed cell proliferation, cell cycle progression and migration, whereas SETDB1 abated miR-381-3p-mediated regulatory function on breast cancer cells. CONCLUSIONS: This study revealed that SETDB1 knockdown might suppress breast cancer progression at least partly by miR-381-3p-related regulation, providing a novel prospect in breast cancer therapy.

Twist1 regulates the epithelial-mesenchymal transition via the NF-κB pathway in papillary thyroid carcinoma.

Expression of the oncogene Twist1 is correlated with tumor development and metastasis. Recent studies have suggested that the epithelial-to-mesenchymal transition (EMT) is necessary for tumor progression and metastases. Little is known concerning the role of Twist1 and EMT in thyroid cancer. In the present work, the expression levels of Twist1 and one marker of EMT, vimentin, were measured in papillary thyroid carcinoma (PTC). The results showed Twist1 expression to be correlated only with cancer lymph node metastases (P = 0.004) and not with other clinicopathological indicators. Moreover, Twist1 expression was positively correlated with the expression of vimentin (r = 0.408, P = 0.003). In vitro studies further indicated that reducing Twist1 expression using short hairpin RNA against Twist1 can decrease the invasive and metastatic properties of PTC cells and that the down-regulation of Twist1 can reverse EMT by increasing the expression of E-cadherin and down-regulating the expression of vimentin in the PTC cell line IHH-4. To investigate the effects on Twist1, the PTC cell lines TPC-1 and BCPAP were treated with TNF-α, resulting in Twist1 up-regulation that was dependent on NF-κB activation. After the inhibition of NF-κB activity with Bay11-7082, the Twist1 mRNA and protein levels could not be increased. The decline in the Twist1 mRNA and protein levels rendered the cancer cells less invasive. Thus, we conclude that Twist1 plays an important role in the EMT of PTC via the NF-κB pathway.

Inflammatory mediators, tumor necrosis factor-α and interferon-γ, induce EMT in human PTC cell lines.

Inflammatory mediators, tumor necrosis factor (TNF)-α and interferon (IFN)-γ, promote adverse outcomes in numerous types of cancer; however, their role in papillary thyroid cancer (PTC) remains unclear. The aim of the present study was to investigate the influence of TNF-α and IFN-γ on the migration, invasion and epithelial-mesenchymal transition (EMT) of the three PTC cell lines, TPC-1, BCPAP and K1. The effect of TNF-α and IFN-γ on cell migration and invasion was assessed by wound-healing and Transwell assays. In addition, the mRNA and protein expression levels of the EMT makers, E-cadherin, N-cadherin and vimentin, were analyzed using reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and immunoblot analysis. The wound-healing and Transwell experiments revealed that TNF-α and IFN-γ increased the migratory and invasive behavior of PTC cells (P<0.05). RT-qPCR revealed that TNF-α and IFN-γ downregulated E-cadherin mRNA, while they upregulated N-cadherin and vimentin mRNA expression levels. These results were further confirmed by the immunoblot analysis. The results of the present study suggest that TNF-α and IFN-γ induce EMT and malignant progression in human PTC cells.