Compressively Strained Fe3O4 in Core-Shell Oxygen Reduction Electrocatalyst Boosts Zinc-Air Battery Performance.

Fe3O4 is barely taken into account as an electrocatalyst for oxygen reduction reaction (ORR), an important reaction for metal-air batteries and fuel cells, due to its sluggish catalytic kinetics and poor electron conductivity. Herein, how strain engineering can be employed to regulate the local electronic structure of Fe3O4 for high ORR activity is reported. Compressively strained Fe3O4 shells with 2.0% shortened Fe─O bond are gained on the Fe/Fe4N cores as a result of lattice mismatch at the interface. A downshift of the d-band center occurs for compressed Fe3O4, leading to weakened chemisorption energy of oxygenated intermediates, and lower reaction overpotential. The compressed Fe3O4 exhibits greatly enhanced electrocatalytic ORR activity with a kinetic current density of 27 times higher than that of pristine one at 0.80 V (vs reversible hydrogen electrode), as well as potential application in zinc-air batteries. The findings provide a new strategy for tuning electronic structures and improving the catalytic activity of other metal catalysts.

LiF/Li3N-Rich Electrode-Electrolyte Interfaces Enabled by Multi-Functional Electrolyte Additive to Achieve High-Performance Li/LiNi0.8Co0.1Mn0.1O2 Batteries.

LiPF6-based carbonate electrolytes have been extensively employed in commercial Li-ion batteries, but they face numerous interfacial stability challenges while applicating in high-energy-density lithium-metal batteries (LMBs). Herein, this work proposes N-succinimidyl trifluoroacetate (NST) as a multifunctional electrolyte additive to address these challenges. NST additive could optimize Li+ solvation structure and eliminate HF/H2O in the electrolyte, and preferentially be decomposed on the Ni-rich cathode (LiNi0.8Co0.1Mn0.1O2, NCM811) to generate LiF/Li3N-rich cathode-electrolyte interphase (CEI) with high conductivity. The synergistic effect reduces the electrolyte decomposition and inhibits the transition metal (TM) dissolution. Meanwhile, NST promotes the creation of solid electrolyte interphase (SEI) rich in inorganics on the Li metal anode (LMA), which restrains the growth of Li dendrites, minimizes parasitic reactions, and fosters rapid Li+ transport. As a result, compared with the reference, the Li/LiNi0.8Co0.1Mn0.1O2 cell with 1.0 wt.% NST exhibits higher capacity retention after 200 cycles at 1C (86.4% vs. 64.8%) and better rate performance, even at 9C. In the presence of NST, the Li/Li symmetrical cell shows a super-stable cyclic performance beyond 500 h at 0.5 mA cm-2/0.5 mAh cm-2. These unique features of NST are a promising solution for addressing the interfacial deterioration issue of high-capacity Ni-rich cathodes paired with LMA.

Atomic Engineering Modulates Oxygen Reduction of Hollow Carbon Matrix Confined Single Metal-Nitrogen Sites for Zinc-Air Batteries.

The systematical understanding of metal-dependent activity in electrocatalyzing oxygen reduction reaction (ORR), a vital reaction with sluggish kinetics for zinc-air batteries, remains quite unclear. An atomic and spatial engineering modulating ORR activity over hollow carbon quasi-sphere (HCS) confined in a series of single M-N (M = Cu, Mn, Ni) sites is reported here. Based on the theoretical prediction and experimental validation, Cu-N4 site with the lowest overpotential shows a better ORR kinetics than Mn-N4 and Ni-N4 . The ORR activity of single-atom Cu center can be further improved by decreasing the coordination number of N to two, namely Cu-N2 , due to the enhancement of electrons with lower coordination structure. Benefitting from the unique spatial confinement effect of the HCS structure in modulating electronic feature of active sites, the Cu-N2 site confined in HCS also delivers highly improved ORR kinetics and activity relative to that on planner graphene. Additionally, the best catalyst holds excellent promise in the application of zinc-air batteries. The findings will pave a new way to atomically and electronically tune active sites with high efficiency for other single-atom catalysts.

NADPH-cytochrome P450 reductase knockdown decreases the response to precocene I in the migratory locust Locusta migratoria.

Precocene I is a juvenile hormone antagonist that needs to be activated via oxidative biotransformation catalyzed by cytochrome P450 (CYP). NADPH-cytochrome P450 reductase (CPR) supplies CYP with electrons in the oxidation-reduction process; however, its functional role in the activation of precocene I remains unexplored. Here, the representative characteristics of CPRs were analyzed in the CPR gene of Locusta migratoria (LmCPR), the result of model docking indicated that the hydrogen bonds were formed between reduced nicotinamide adenine dinucleotide phosphate (NADPH), flavin adenine dinucleotide (FAD), flavin mononucleotide (FMN) and NADPH-, FAD-, FMN-domains of LmCPR, respectively. Treating the fourth-instar nymphs with precocene I decreased the juvenile hormone titers of nymphs to 0.55-fold of that in acetone-treated controls, and extended the interval time between fourth- and fifth-instar nymphs. 68.75% of the treated fourth-instar nymphs developed into precocious adults in the fifth-instar. LmCPR knockdown decreased the response to precocene I in the nymphs, the occurrence rate of precocious adults induced by precocene I treatment reduced by 23.11%. Therefore, LmCPR may be involved in the activation of precocene I in L. migratoria. In addition, we generated an active recombinant LmCPR protein using a prokaryotic expression system, its activity in reducing cytochrome c was 33.13 ± 11.50 nmol CytCred/min/µg protein. This study lays the foundation for further research on the role of LmCPR in precocene I activation.

Transcription factors, cap 'n' collar isoform C regulates the expression of CYP450 genes involving in insecticides susceptibility in Locusta migratoria.

BACKGROUND: The cap 'n' collar (Cnc) belongs to the Basic Leucine Zipper (bZIP) transcription factor super family. Cap 'n' collar isoform C (CncC) is highly conserved in the animal kingdom. CncC contributes to the regulation of growth, development, and aging and takes part in the maintenance of homeostasis and the defense against endogenous and environmental stress. Insect CncC participates in the regulation of various kinds of stress-responsive genes and is involved in the development of insecticide resistance. RESULTS: In this study, one full-length CncC sequence of Locusta migratoria was identified and characterized. Upon RNAi silencing of LmCncC, insecticide bioassays showed that LmCncC played an essential role in deltamethrin and imidacloprid susceptibility. To fully investigate the downstream genes regulated by LmCncC and further identify the LmCncC-regulated genes involved in deltamethrin and imidacloprid susceptibility, a comparative transcriptome was constructed. Thirty-five up-regulated genes and 73 down-regulated genes were screened from dsLmCncC-knockdown individuals. We selected 22 LmCncC-regulated genes and verified their gene expression levels using RT-qPCR. Finally, six LmCYP450 genes belonging to the CYP6 family were selected as candidate detoxification genes, and LmCYP6FD1 and LmCYP6FE1 were further validated as detoxification genes of insecticides via RNAi, insecticide bioassays, and metabolite identification. CONCLUSIONS: Our data suggest that the locust CncC gene is associated with deltamethrin and imidacloprid susceptibility via the regulation of LmCYP6FD1 and LmCYP6FE1, respectively.

Transcription factor CncC regulates the expression of antennal CYP6MU1 gene responsible for trans-2-hexen-1-al and nonanal recognition in Locusta migratoria.

Cytochrome P450 monooxygenases (P450s) are a superfamily of multifunctional heme-containing proteins and could function as odorant-degrading enzymes (ODEs) in insect olfactory systems. In our previous study, we identified a P450 gene from the antennal transcriptome of Locusta migratoria, LmCYP6MU1, which could be induced by a variety of volatiles. However, the regulatory mechanisms of this gene in response to volatiles remain unknown. In current study, we investigated the tissues and development stages expression patterns of LmCYP6MU1 and determined its olfactory function in the recognition of the main host plant volatiles which induced LmCYP6MU1 expression. The results showed that LmCYP6MU1 was antenna-rich and highly expressed throughout the antennal developmental stages of locusts. LmCYP6MU1 played important roles in the recognition of trans-2-hexen-1-al and nonanal. Insect CncC regulates the expression of P450 genes. We tested whether LmCncC regulates LmCYP6MU1 expression. It was found that LmCncC knockdown in the antennae resulted in the downregulation of LmCYP6MU1 and repressed the volatiles-mediated induction of LmCYP6MU1. LmCncC knockdown reduced the electroantennogram (EAG) and behavioral responses of locusts to volatiles. These results suggested that LmCncC could regulate the basal and volatiles-mediated inducible expression of LmCYP6MU1 responsible for the recognition of trans-2-hexen-1-al and nonanal. These findings provide an original basis for understanding the regulation mechanisms of LmCncC on LmCYP6MU1 expression and help us better understand the LmCncC-mediated olfactory plasticity.

CYP6FD5, an antenna-specific P450 gene, is potentially involved in the host plant recognition in Locusta migratoria.

Cytochrome P450 monooxygenases (P450s) are a large superfamily of heme-thiolate proteins and play a vital role in the biosynthesis and inactivation of endogenous substances as well as the detoxification of exogenous substances. They also function as odor-degrading enzymes (ODEs) in insect olfactory sensory systems. In the present study, a P450 gene was obtained from the antennae of Locusta migratoria and named as CYP6FD5. Multiple alignment of P450 proteins revealed that LmCYP6FD5 contained five conserved motifs, including the helix C motif, an oxygen-binding site, helix K motif, a meander region, and the haem-binding motif. The expression of LmCYP6FD5 in various tissues and antennal development stages was determined by using RT-qPCR. Our results showed that LmCYP6FD5 was antenna-specific and highly expressed throughout the antennal developmental stages of female and male locusts. Furthermore, the role of LmCYP6FD5 in the perception of host plant volatiles was assessed using RNAi in combination with electroantennogram (EAG) and behavioral responses. Our findings showed that after silencing LmCYP6FD5, the EAG responses of female and male locusts to the main volatiles of gramineous plants, including trans-2-Hexen-1-al, cis-3-Hexenyl acetate, and decanal, were significantly diminished. Moreover, a significant decrease in EAG response of male antennae to benzaldehyde was also observed. In addition, behavioral assay showed that the locust response to single volatile from host plant or wheat remained unchanged after the silencing of LmCYP6FD5. Antenna-specific expression and EAG responses of locusts to host plant volatiles still suggested that LmCYP6FD5 was potentially involved in host plant recognition, although no behavioral changes were observed.

A nomogram to predict stricture-free survival in patients with ureteral stricture after balloon dilation.

BACKGROUND: Balloon dilation is a commonly used minimally invasive endourological treatment of ureteral stricture, but the postoperative recurrence rate is relatively high. And factors contributing to recurrence after treatment are poorly understood. Herein, we sought to develop a novel clinical nomogram to predict ureteral stricture-free survival in patients suffering from ureter stricture and performed balloon dilation. METHODS: The nomogram was established based on a retrospective analysis of 321 patients who received endoscopic balloon dilation alone for ureter strictures from January 2016 to January 2020 in Sun Yat-sen Memorial Hospital using the Cox regression model. Perioperative clinical data and disease outcomes were analyzed. The primary endpoint was the onset of ureteral re-stricture after ureter balloon dilation. Discrimination of the nomogram was assessed by the concordance index (C-index) and the calibration curve. The results were internally validated using bootstrap resampling. RESULTS: Overall, 321 patients with a median follow-up of 590 days were enrolled in the study, among which 97 patients (30.2%) developed recurrence of ureteral stricture during follow-up. Five variables remained significant predictors of ureteral re-stricture after multivariable analyses: stricture nature (P < 0.001), urinary nitrite (P = 0.041), CKD (P = 0.005), stent retention time (P < 0.001), and balloon size (P = 0.029). The calibration craves for the probability of 1-, 3-, and 5-years stricture-free survival (SFS) presented satisfied with the consistency of nomogram prediction and actual observation. The C-index of the model was 0.74 (95% CI 0.70-0.79). CONCLUSIONS: Our study developed the first nomogram to effectively predict stricture-free survival in patients suffering from ureter stricture after balloon dilation. It is helpful to identify the optimal patients with ureter stricture for balloon dilation and improve treatment outcomes. However, further external validation of the nomogram is warranted.

Effect of Deep-Defects Excitation on Mechanical Energy Dissipation of Single-Crystal Diamond.

The ultrawide band gap of diamond distinguishes it from other semiconductors, in that all known defects have deep energy levels that are less active at room temperature. Here, we present the effect of deep defects on the mechanical energy dissipation of single-crystal diamond experimentally and theoretically up to 973 K. Energy dissipation is found to increase with temperature and exhibits local maxima due to the interaction between phonons and deep defects activated at specific temperatures. A two-level model with deep energies is proposed to explain well the energy dissipation at elevated temperatures. It is evident that the removal of boron impurities can substantially increase the quality factor of room-temperature diamond mechanical resonators. The deep energy nature of the defects bestows single-crystal diamond with outstanding low intrinsic energy dissipation in mechanical resonators at room temperature or above.

A second intracellular copper/zinc superoxide dismutase and a manganese superoxide dismutase in Oxya chinensis: Molecular and biochemical characteristics and roles in chlorpyrifos stress.

A second intracellular copper/zinc superoxide dismutase (icCuZnSOD2) and manganese SOD (MnSOD) were cloned and characterized in Oxya chinensis. The open reading frame (ORF) of OcicCuZnSOD2 and OcMnSOD are 462 and 672 bp encoding 153 and 223 amino acids, respectively. OcicCuZnSOD2 contains two signature sequences, one potential N-glycosylation site, and seven copper/zinc binding sites. OcMnSOD includes a mitochondria targeting sequence of 7 amino acids at N-terminal, one signature sequence, two N-glycosylation sites, and four manganese binding sites. The secondary structure and homology model of OcicCuZnSOD2 include nine ß sheets, two Greek-key motifs, and one electrostatic loop. OcMnSOD contains nine α-helices and three ß-sheets. Phylogenetic analysis shows that OcMnSOD is evolutionarily conserved while OcicCuZnSOD2 may be gene duplication and is paralogous to OcicCuZnSOD1. OcMnSOD expressed widely in all tissues and developmental stages. OcicCuZnSOD2 showed testis-specific expression and expressed highest in the 5th-instar nymph and the adult. The optimum temperatures and pH values of the recombinant OcicCuZnSOD2 and OcMnSOD were 40 °C and 8.0. They were stable at 25-55 °C and at pH 5.0-12.0 and pH 6.0-12.0, respectively. The activity and mRNA expression of each OcSOD were assayed after chlorpyrifos treatments. Total SOD and CuZnSOD activities first increased then declined under chlorpyrifos stress. Chlorpyrifos induced the mRNA expression and activity of OcMnSOD as a dose-dependent manner and inhibited OcicCuZnSOD2 transcription. The role of each OcSOD gene in chlorpyrifos stress was investigated using RNAi and disc diffusion assay with Escherichia coli overexpressing OcSOD proteins. Silencing of OcMnSOD significantly increased ROS content in chlorpyrifos-exposed grasshoppers. Disc diffusion assay showed that the plates with E. coli overexpressing OcMnSOD had the smaller inhibition zones around the chlorpyrifos-soaked filter discs. These results implied that OcMnSOD played a significant role in defense chlorpyrifos-induced oxidative stress.

Antioxidant defenses at enzymatic and transcriptional levels in response to acute lead administration in Oxya chinensis.

Lead (Pb) is known to be toxic to many organisms. Oxidative stress is a major mechanism of its toxicity. This research aims to investigate the effects of Pb on hydrogen peroxide (H2O2) and malonedialdehyde (MDA) contents, activities and mRNA levels of antioxidant enzymes (superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx)) after Oxya chinensis were acutely treated with lead acetate for 24 h. The results showed that the LD50-24 h value of lead acetate to O. chinensis was 1541.89 (1431.19-1655.77) µg g-1 body H2O2 and MDA contents were elevated after Pb administration, which suggested that Pb induced the overproduction of ROS and caused oxidative stress. SOD activities were significantly inhibited 40.42% of the control by 280 µg µL-1 Pb. CAT activities were increased while GPx activities had no significant changes. Different types of antioxidant-related genes had various responses to Pb stress. The transcriptions of icCuZnSOD2 and ecCuZnSOD2 were significantly inhibited by different concentrations of Pb. MnSOD mRNA levels showed the concentration-dependent rise with the Pb concentrations increase. The expressions of ecCuZnSOD1, CAT1, and GPx were significantly up-regulated while the transcriptions of icCuZnSOD1 and CAT2 had no significant changes. Alteration of activities and mRNA expressions of antioxidant enzymes implied that Pb-induced antioxidant defenses were related to modifications at enzymatic and transcriptional levels. The profiles of antioxidant enzymes and H2O2 and MDA contents and relationships among the parameters indicated that the cooperation of multiple antioxidants rather than a single factor might be responsible for the antioxidant defenses against Pb stress.

Metabolism of selected model substrates and insecticides by recombinant CYP6FD encoded by its gene predominately expressed in the brain of Locusta migratoria.

The migratory locust, Locusta migartoria, is a major agricultural insect pest and its resistance to insecticides is becoming more prevalent. Cytochrome P450 monooxygenases (CYPs) are important enzymes for biotransformations of various endogenous and xenobiotic substances. These enzymes play a major role in developing insecticide resistance in many insect species. In this study, we heterologously co-expressed a CYP enzyme (CYP6FD1) and cytochrome P450 reductase (CPR) from L. migartoria in Sf9 insect cells. The recombinant enzymes were assayed for metabolic activity towards six selected model substrates (luciferin-H, luciferin-Me, luciferin-Be, luciferin-PFBE, luciferin-CEE and 7-ethoxycoumarin), and four selected insecticides (deltamethrin, chlorpyrifos, carbaryl and methoprene). Recombinant CYP6FD1 showed activity towards 7-ethoxycoumarin and luciferin-Me, but no detectable activity towards the other luciferin derivatives. Furthermore, the enzyme efficiently oxidized deltamethrin to hydroxydeltamethrin through an aromatic hydroxylation in a time-dependent manner. However, the enzyme did not show any detectable activity towards the other three insecticides. Our results provide direct evidence that CYP6FD1 is capable of metabolizing deltamethrin. This work is a step towards a more complete characterization of the catalytic capabilities of CYP6FD1 and other xenobiotic metabolizing CYP enzymes in L. migratoria.

Construction of a sp3 /sp2 Carbon Interface in 3D N-Doped Nanocarbons for the Oxygen Reduction Reaction.

The development of highly efficient metal-free carbon electrocatalysts for the oxygen reduction reaction (ORR) is one very promising strategy for the exploitation and commercialization of renewable and clean energy, but this still remains a significant challenge. Herein, we demonstrate a facile approach to prepare three-dimensional (3D) N-doped carbon with a sp3 /sp2 carbon interface derived from ionic liquids via a simple pyrolysis process. The tunable hybrid sp3 and sp2 carbon composition and pore structures stem from the transformation of ionic liquids to polymerized organics and introduction of a Co metal salt. Through tuning both composition and pores, the 3D N-doped nanocarbon with a high sp3 /sp2 carbon ratio on the surface exhibits a superior electrocatalytic performance for the ORR compared to that of the commercial Pt/C in Zn-air batteries. Density functional theory calculations suggest that the improved ORR performance can be ascribed to the existence of N dopants at the sp3 /sp2 carbon interface, which can lower the theoretical overpotential of the ORR.

Cadmium exposure on tissue-specific cadmium accumulation and alteration of hemoglobin expression in the 4th-instar larvae of Propsilocerus akamusi (Tokunaga) under laboratory conditions.

The expression of hemoglobin (Hb) genes has considerable potential as a biomarker for environmental monitoring in Chironomus. However, no sequence information is available regarding Hb genes in Propsilocerus akamusi (Tokunaga), thus the change in Hb mRNA gene expression caused by environmental pollutants remains unknown. In this study, we cloned two Hb gene fragments (PaHbV and PaHbVII) from P. akamusi, analyzed the expression patterns of the PaHbV and PaHbVII transcripts in different tissues using Real-Time quantitative PCR (RT-qPCR), and also measured the Cd levels in different tissues exposed to a sublethal concentration. The results showed significantly increased Cd concentrations and tissue-specific Cd distribution patterns in all of the tissues tested, including the hemolymph, during all time courses. A model describing the roles of specific tissues in Cd uptake and accumulation dynamics was also determined. The Malpighian tubules, gut, and epidermis were the primary sites of Cd accumulation, whereas the hemolymph was the temporary target organ of Cd accumulation, with the Cd being transferred to other internal tissues via the hemolymph. The relative mRNA expression profiles of PaHbV and PaHbVII indicated that their expression levels differed across the different tissues, indicating a tissue-specific response. Our results suggested a reverse effect between Hb expression and Cd accumulation during long-term Cd exposure in comparison with previous studies. The expressions of Hb genes in P. akamusi could be developed as biomarkers for assessing the general health conditions of freshwater ecosystems.

Antioxidant enzymes and their role in phoxim and carbaryl stress in Caenorhabditis elegans.

Pesticide exposure can induce oxidative stress and cause changes to antioxidant enzymes in living organisms. In the present study, the effects of phoxim (an organophosphorus insecticide) and carbaryl (a carbamate insecticide) on antioxidant enzyme activity and gene expression were investigated in the model organism Caenorhabditis elegans. The results show that phoxim exposure can induce superoxide dismutase (SOD) and catalase (CAT) activities and decrease glutathione peroxidase (GPx) activity at lower concentrations. The expression levels of sod-3, sod-5, ctl-1, gpx-6, and gpx-8 were up-regulated after treatment with phoxim. The mRNA expression levels of sod-5, ctl-1 and gpx-6 were increased approximately 70-, 170- and 130-fold, respectively, in the 0.25mM treatment group compared to the control group. Carbaryl exposure decreased SOD activity and induced CAT and GPx activities. The addition of carbaryl up-regulated the expression of sod-5, ctl-1, ctl-3 and gpx-8. Specifically, ctl-1 expression increased approximately 10-fold, and gpx-8 expression increased <30-fold in the 0.5mM treatment group relative to the control group. The transcript level of sod-5 increased >20-fold, and ctl-3 increased approximately 10-fold in the 1mM treatment group. The functions of the antioxidant enzymes during oxidative stress caused by the two insecticides were investigated using deletion mutants. The LC50 values phoxim for the of sod-3 (tm760), sod-5 (tm1146), ctl-1 (ok1242), ctl-3 (ok2042) and gpx-8 (tm2108) mutant strains were lower than those observed for the N2 strain. The LC50 values of carbaryl for the ctl-1 (ok1242), ctl-3 (ok2042) and gpx-6 (tm2535) deletion mutant strains decreased in comparison to the N2 strain. The results suggest that these two insecticides caused oxidative stress and changed altered the antioxidant enzyme activities and their gene expressions in C. elegans. The sod-3, sod-5, ctl-1, ctl-3, gpx-6, and gpx-8 encoding enzymes may play roles in defending cells from oxidative stress caused by these two insecticides.

Susceptibility and potential biochemical mechanism of Oedaleus asiaticus to beta-cypermethrin and deltamethrin in the Inner Mongolia, China.

Oedaleus asiaticus is a highly destructive grass pest in Inner Mongolia, China, and likely developed resistance to pyrethroid insecticides due to their frequent application for control of this locust. In this study, the susceptibility of five field populations of O. asiaticus to two pyrethroid insecticides was investigated. The Wulate Middle Banner (WB) population was the least susceptible, whereas the Ewenki Banner (EB) population appeared to be the most sensitive. The WB population was 3.16 and 5.15-fold less sensitive to beta-cypermethrin and deltamethrin than EB population, respectively. Further, the enzyme activities and mRNA expression levels of carboxylesterase (CarE) and glutathione-S-transferase (GST) were determined and we found that their activities in the WB population were 5.15 and 2.8-fold higher than those in the EB population, respectively. Quantitative real-time PCR (qRT-PCR) analysis demonstrated that the mRNA expression levels of CarE and GST genes were positively correlated with the LD50 in the WB, Siziwang Banner (SB) and EB populations. Our findings suggest that differences in susceptibility to pyrethroids in O. asiaticus might be attributed to the elevated activities and mRNA expression levels of CarE and GST genes.

Identification and characterization of two CYP9A genes associated with pyrethroid detoxification in Locusta migratoria.

Cytochrome P450s (CYPs) constitute one of the largest gene super families and distribute widely in all living organisms. In this study, the full-length cDNA sequences of two LmCYP9A genes (LmCYP9AQ1 and LmCYP9A3) were cloned from Locusta migratoria. We analyzed the expression patterns of two LmCYP9A genes in various tissues and different developmental stages using real-time quantitative PCR. Then we evaluated the detoxification functions of the two LmCYP9A genes by testing mortalities with four kinds of pyrethroid treatment after RNA interference (RNAi), respectively. Combining with docking structure of two LmCYP9A genes, their detoxification properties were extensively analyzed. The full-length cDNAs of LmCYP9AQ1 and LmCYP9A3 putatively encoded 525 and 524 amino acid residues, respectively. Both LmCYP9A genes were expressed throughout the developmental stages. The expression of LmCYP9AQ1 in the brain was higher than that in other examined tissues, whereas the LmCYP9A3 was mainly expressed in the fat body. The mortalities of nymphs exposed to deltamethrin and permethrin increased from 27.7% to 77.7% and 27.7% to 58.3%, respectively, after dsLmCYP9A3 injection. While the mortalities of nymphs exposed to fluvalinate increased from 29.8% to 53.0% after LmCYP9AQ1 was silenced using RNA interference. Our results suggested that the two LmCYP9A genes may be involved in different pyrethroid insecticide detoxification in L. migratoria.

Identification and functional analysis of a cytochrome P450 gene CYP9AQ2 involved in deltamethrin detoxification from Locusta migratoria.

A 1578-bp cDNA of a cytochrome P450 gene (CYP9AQ2) was sequenced from the migratory locust, Locusta migratoria. It contains an open reading frame (ORF) of 1557 bp that encodes 519 amino acid residues. As compared with other known insect cytochrome P450 enzymes, the overall structure of its deduced protein is highly conserved. The expression of CYP9AQ2 was relatively higher in nymphal stages than in egg and adult stages, and the highest expression was found in fourth-instar nymphs, which was 8.7-fold higher than that of eggs. High expression of CYP9AQ2 was observed in foregut, followed by hindgut, Malpighian tubules, brain and fat bodies, which were 75~142-fold higher than that in hemolymph. Low expression was found in midgut, gastric cecum and hemolymph. The expression of CYP9AQ2 was up-regulated by deltamethrin at the concentrations of 0.04, 0.08, and 0.12 µg/mL and the maximal up-regulation was 2.6-fold at LD10 (0.04 µg/mL). RNA interference-mediated silencing of CYP9AQ2 led to an increased mortality of 25.3% when the nymphs were exposed to deltamethrin, suggesting that CYP9AQ2 plays an important role in deltamethrin detoxification in L. migratoria. Computational docking studies suggested that hydroxylation of the phenoxybenzyl moiety might be one of the deltamethrin metabolic pathways by CYP9AQ2.

Developing discriminate model and comparative analysis of differentially expressed genes and pathways for bloodstream samples of diabetes mellitus type 2.

BACKGROUND: Diabetes mellitus of type 2 (T2D), also known as noninsulin-dependent diabetes mellitus (NIDDM) or adult-onset diabetes, is a common disease. It is estimated that more than 300 million people worldwide suffer from T2D. In this study, we investigated the T2D, pre-diabetic and healthy human (no diabetes) bloodstream samples using genomic, genealogical, and phonemic information. We identified differentially expressed genes and pathways. The study has provided deeper insights into the development of T2D, and provided useful information for further effective prevention and treatment of the disease. RESULTS: A total of 142 bloodstream samples were collected, including 47 healthy humans, 22 pre-diabetic and 73 T2D patients. Whole genome scale gene expression profiles were obtained using the Agilent Oligo chips that contain over 20,000 human genes. We identified 79 significantly differentially expressed genes that have fold change ≥ 2. We mapped those genes and pinpointed locations of those genes on human chromosomes. Amongst them, 3 genes were not mapped well on the human genome, but the rest of 76 differentially expressed genes were well mapped on the human genome. We found that most abundant differentially expressed genes are on chromosome one, which contains 9 of those genes, followed by chromosome two that contains 7 of the 76 differentially expressed genes. We performed gene ontology (GO) functional analysis of those 79 differentially expressed genes and found that genes involve in the regulation of cell proliferation were among most common pathways related to T2D. The expression of the 79 genes was combined with clinical information that includes age, sex, and race to construct an optimal discriminant model. The overall performance of the model reached 95.1% accuracy, with 91.5% accuracy on identifying healthy humans, 100% accuracy on pre-diabetic patients and 95.9% accuract on T2D patients. The higher performance on identifying pre-diabetic patients was resulted from more significant changes of gene expressions among this particular group of humans, which implicated that patients were having profound genetic changes towards disease development. CONCLUSION: Differentially expressed genes were distributed across chromosomes, and are more abundant on chromosomes 1 and 2 than the rest of the human genome. We found that regulation of cell proliferation actually plays an important role in the T2D disease development. The predictive model developed in this study has utilized the 79 significant genes in combination with age, sex, and racial information to distinguish pre-diabetic, T2D, and healthy humans. The study not only has provided deeper understanding of the disease molecular mechanisms but also useful information for pathway analysis and effective drug target identification.

Acute toxicity and sublethal effects of fipronil on detoxification enzymes in juvenile zebrafish (Danio rerio).

The acute toxicity of fipronil and its sublethal effects on detoxification enzymes (carboxylesterases (CarEs), glutathione S-transferases (GSTs), and 7-ethoxycoumarin O-deethylase (ECOD)) in zebrafish (Danio rerio) were investigated. The results indicated that the 24-h LC50 of fipronil for zebrafish was 220.4 µg/L (95% CI: 173.7-272.4 µg/L). Sublethal concentrations of fipronil did not cause significant changes in CarEs activities. In the liver and muscle tissues, GST activities at the tested concentrations did not significantly differ from those in the control. In the brain and gill tissues, GST activities at a concentration of 4 µg/L were significantly lower than those at a concentration of 2 µg/L. The results suggest that CarEs and GSTs were not suitable biomarkers for fipronil effects in D. rerio. A significant induction in the ECOD activities in the brain, gill, liver, and muscle tissues was observed compared with the control. Moreover, the dose-dependent responses of the ECOD activity were observed after treatment with sublethal concentrations of fipronil in the range of 2-20 µg/L. The results suggested that ECOD could be a suitable biomarker of fipronil effects in D. rerio.