Disparities in Genetic Diversity Drive the Population Displacement of Two Invasive Cryptic Species of the Bemisia tabaci Complex in China.

Within the whitefly Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) complex, two cryptic species, namely Middle East-Asia Minor 1 (MEAM1) and Mediterranean (MED), are important invasive pests affecting global agriculture and horticulture. They were introduced into China sequentially in the mid-1990s and around 2003, respectively. Subsequently, the latter invader MED has outcompeted the earlier invader MEAM1, becoming the dominant population in the field. Although extensive studies have explored the underlying mechanisms driving this shift, the contribution of population genetics remains notably underexplored. In this study, we analyzed the genetic diversity and structure of 22 MED and 8 MEAM1 populations from various regions of China using mitochondrial DNA sequencing and microsatellite genotyping. Our results indicate low and moderate levels of genetic differentiation among geographically separate populations of MED and MEAM1, respectively. Median-joining network analysis of mtCOI gene haplotypes revealed no clear geographic structuring for either, with common haplotypes observed across provinces, although MED had more haplotypes. Comparative analyses revealed that MED presented greater genetic diversity than MEAM1 on the basis of two markers. Furthermore, analysis of molecular variance supported these findings, suggesting that while some genetic variation exists between populations, a significant amount is also present within populations. These findings reveal the population genetics of the two invasive cryptic species of the B. tabaci complex in China and suggest that the disparities in genetic diversity drive the displacement of their populations in the field. This work also provides valuable information on the genetic factors influencing the population dynamics and dominance of these invasive whitefly species.

Surface Reconstruction of Microscale Objects Based on Grid-Patterned Structured-Light Measurements.

A structured-light projection system was designed for microscale objects with surface heights that ranged from tens to hundreds of microns. The system was composed of a universal projector and microscope system that supported editing the attributes of structured-light patterns in real-time and was capable of projecting microscale patterns. On this basis, reconstructing the metal surfaces of microscale objects based on grid patterns of structured light was investigated, the internal and external parameters of microscope vision and projection systems were calibrated, and an image algorithm for grid-node detection was designed. The results indicated that the proposed method successfully reconstructed the three-dimensional (3D) surface of microscale objects, and the reconstruction results were consistent with the original surfaces. With 95% confidence, the reconstruction precision in the X- and Y-directions was approximately ±4.0 µm and in the Z-direction was approximately ±7.5 µm. The designed system and the proposed method were suitable for 3D-shape measurement of microstructures in microscopic fields and can be adapted to meet a broader range of applications, as compared to current methods.

The microstructure and property of Al-Si alloy improved by the Sc-microalloying and Y2O3 nano-particles.

The effect of Sc-microalloying and Y2O3 nano-particles on the microstructure and mechanical properties of as-cast Al-5.5Si alloy is studied by means of optical microscopy, transmission electron microscopy, hardness test and tensile test. The influence of annealing treatment on the microstructure and properties of the Al-Si alloys is also investigated as well. The results show that the addition of Sc and Y2O3 nano-particles could significantly improve the mechanical property of the Al-Si alloy. The ultimate tensile strength and yield strength of Al-Si-Sc/Y2O3 alloy are improved by around 45 and 71%, respectively, when compared to that of the Al-Si alloy. The effect of the nanosized particles (precipitated and added) on strengthening and deformation of Al-Si alloy is analyzed and discussed in detail. The results of annealing treatment indicate that the change in mechanical property of the Al-Si-Sc alloy during annealing treatment is mainly associated with the precipitation of the secondary Si phase.

Cyclic Multiblock Copolymers via Combination of Iterative Cu(0)-Mediated Radical Polymerization and Cu(I)-Catalyzed Azide-Alkyne Cycloaddition Reaction.

Cyclic multiblock polymers with high-order blocks are synthesized via the combination of single-electron transfer living radical polymerization (SET-LRP) and copper-catalyzed azide-alkyne cycloaddition (CuAAC). The linear α,ω-telechelic multiblock copolymer is prepared via SET-LRP by sequential addition of different monomers. The SET-LRP approach allows well control of the block length and sequence as A-B-C-D-E, etc. The CuAAC is then performed to intramolecularly couple the azide and alkyne end groups of the linear copolymer and produce the corresponding cyclic copolymer. The block sequence and the cyclic topology of the resultant cyclic copolymer are confirmed by the characterization of 1 H nuclear magnetic resonance spectroscopy, gel permeation chromatography, Fourier transform infrared spectroscopy, and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry.

Asymmetric hydrogenation of α,α'-disubstituted cycloketones through dynamic kinetic resolution: an efficient construction of chiral diols with three contiguous stereocenters.

Chiral diols with three contiguous stereocenters were synthesized by a highly enantioselective ruthenium-catalyzed asymmetric hydrogenation of racemic α,α'-disubstituted cycloketones involving dynamic kinetic resolution. This new catalytic asymmetric method provides a concise route to the alkaloid (+)-γ-lycorane.

Correction of Rotational Eccentricity Based on Model and Microvision in the Wire-Traction Micromanipulation System.

In the realm of automatic wire-traction micromanipulation systems, the alignment of the central axis of the coil with the rotation axis of the rotary stage can be a challenge, which leads to the occurrence of eccentricity during rotation. The wire-traction is conducted at a micron-level of manipulation precision on micron electrode wires; eccentricity has a significant impact on the control accuracy of the system. To resolve the problem, a method for measuring and correcting the coil eccentricity is proposed in this paper. First, models of radial and tilt eccentricity are established respectively based on the eccentricity sources. Then, measuring eccentricity is proposed by an eccentricity model and microscopic vision; the model is used to predict eccentricity, and visual image processing algorithms are used to calibrate model parameters. In addition, a correction based on the compensation model and hardware is designed to compensate for the eccentricity. The experimental results demonstrate the accuracy of the models in predicting eccentricity and the effectiveness of correction. The results show that the models have an accurate prediction for eccentricity that relies on the evaluation of the root mean square error (RMSE); the maximal residual error after correction was within 6 µm, and the compensation was approximately 99.6%. The proposed method, which combines the eccentricity model and microvision for measuring and correcting eccentricity, offers improved wire-traction micromanipulation accuracy, enhanced efficiency, and an integrated system. It has more suitable and wider applications in the field of micromanipulation and microassembly.

Inhibition of Rac activity alleviates lipopolysaccharide-induced acute pulmonary injury in mice.

BACKGROUND: Rac small GTPases play important roles in cytoskeleton and many cell functions including cell cycle, cell growth, cell adhesion and gene transcription. Here, we investigated the roles of Rac including Rac1 and Rac2 in lipopolysaccharide (LPS)-induced pulmonary injury. METHODS: After LPS was intratracheally instilled to lungs in mice, Rac, CDC42 and RhoA activation assay by pull-down and West blot, inflammatory cell infiltration assay by counting cell numbers and lung histological examination, pro-inflammatory mediator mRNA expression assay by quantitative RT-PCR, measurement of myeloperoxidase (MPO) activity, Evans Blue and albumin accumulation by spectrophotometry were performed to evaluate the roles of Rac in pulmonary injury by using its specific inhibitor, NSC23766. RESULTS: LPS challenge led to increases of both Rac1 and Rac2, but not CDC42 or RhoA activities in lungs, and intraperitoneal administration with NSC23766 inhibited both Rac1 and Rac2, but not CDC42 or RhoA activities. Treatment with NSC23766 at 1 or 3mg/kg not only reduced the inflammatory cells infiltration and MPO activities, but also inhibited pro-inflammatory mediators, tumor necrosis factor-α and interleukin-1ß, mRNA expression. Moreover, in vitro neutrophil migration assay and in vivo microvascular permeability assay indicated that NSC23766 not only inhibited neutrophil transwell migration toward a chemoattractant, fMLP, but also reduced Evans Blue and albumin accumulation in LPS-challenged lungs. LPS activated both Rac1 and Rac2, but not CDC42 or RhoA activities in lungs, and specific inhibition of Rac activities by NSC23766 effectively alleviated LPS-induced injury. GENERAL SIGNIFICANCE: Rac could be a potential target for therapeutic intervention of pulmonary inflammation.

Design, Analysis and Experimental Investigations of a Double-Arm Based Micro-Gripper for Thin and Flexible Metal Wires Manipulation.

A robotic system for the automatic wire pulling of coreless motor winding is designed, including the design of an opening-closing control system and a micro-gripper's tip structure with a double-armed elastic-beam structure for the support part and an enveloping clamping structure for the tip part. The micro-gripper captures the electrode wire from the root, encircles the wire after the envelope region is closed, and the thin and flexible electrode wire is pulled to the top of the electrode pad by the movement of the micro-gripper and released. The mechanical index of the micro-gripper is simulated to obtain the optimal structural parameters. The experimental results show that the electrode wire's maximum bearing force is about 0.3 N. Under this reaction force, the deformation of the tip-envelope region of the micro-gripper is about 27.5 µm, which is sufficient for electrode wire pulling micro-manipulation. By comparison with the steel micro-gripper, the silicon micro-gripper has more advantages in shape integrity, machinability and mechanical properties.

Design of thin-structured-light projection system for small-height measurement.

A thin-structured light projection system with simple setup is proposed and applied to small-height measurement. In this system, the design of structured light pattern is carried out on the computer. The structure, color, geometric dimension, motion mode, projection brightness, contrast, and other attributes of the pattern can be edited easily. The optical system with zoom function is designed, which can output thin-structured-light fringe with a minimum width of 10 µm. The camera and microscope are used to construct a vision system, which is used to capture the pattern of structured light. The three-dimensional (3D) shape reconstruction is realized by analyzing the pattern of structured light. The results show that this system can project a small width of thin-structured light pattern, which is very suitable for 3D shape reconstruction of microscopic objects with the small-height of tens of microns to hundreds of microns.

SERCA interacts with chitin synthase and participates in cuticular chitin biogenesis in Drosophila.

The biogenesis of chitin, a major structural polysaccharide found in the cuticle and peritrophic matrix, is crucial for insect growth and development. Chitin synthase, a membrane-integral ß-glycosyltransferase, has been identified as the core of the chitin biogenesis machinery. However, a yet unknown number of auxiliary proteins appear to assist in chitin biosynthesis, whose precise function remains elusive. Here, we identified a sarco/endoplasmic reticulum Ca2+-ATPase (SERCA), in the fruit fly Drosophila melanogaster, as a chitin biogenesis-associated protein. The physical interaction between DmSERCA and epidermal chitin synthase (Krotzkopf verkehrt, Kkv) was demonstrated and analyzed using split-ubiquitin membrane yeast two-hybrid, bimolecular fluorescent complementation, pull-down, and immunoprecipitation assays. The interaction involves N-terminal regions (aa 48-81 and aa 247-33) and C-terminal regions (aa 743-783 and aa 824-859) of DmSERCA and two N-terminal regions (aa 121-179 and aa 369-539) of Kkv, all of which are predicted be transmembrane helices. While tissue-specific knock-down of DmSERCA in the epidermis caused larval and pupal lethality, the knock-down of DmSERCA in wings resulted in smaller and crinkled wings, a significant decrease in chitin deposition, and the loss of chitin lamellar structure. Although DmSERCA is well-known for its role in muscular contraction, this study reveals a novel role in chitin synthesis, contributing to our knowledge on the machinery of chitin biogenesis.

Fatty acid binding protein is required for chitin biosynthesis in the wing of Drosophila melanogaster.

Chitin, the major structural polysaccharide in arthropods such as insects and mites, is a linear polymer of N-acetylglucosamine units. The growth and development of insects are intimately coupled with chitin biosynthesis. The membrane-bound ß-glycosyltransferase chitin synthase is known to catalyze the key polymerization step of N-acetylglucosamine. However, the additional proteins that might assist chitin synthase during chitin biosynthesis are not well understood. Recently, fatty acid binding protein (Fabp) has been suggested as a candidate that interacts with the chitin synthase Krotzkopf verkehrt (Kkv) in Drosophila melanogaster. Here, using split-ubiquitin membrane yeast two-hybrid and pull-down assays, we have demonstrated that the Fabp-B splice variant physically interacts with Kkv in vitro. The global knockdown of Fabp in D. melanogaster using RNA interference (RNAi) induced lethality at the larval stage. Moreover, in tissue-specific RNAi experiments, silenced Fabp expression in the epidermis and tracheal system caused a lethal larval phenotype. Fabp knockdown in the wings resulted in an abnormal wing development and uneven cuticular surface. In addition to reducing the chitin content in the first longitudinal vein of wings, Fabp silencing also caused the loss of procuticle laminate structures. This study revealed that Fabp plays an important role in chitin synthesis and contributes to a comprehensive understanding of the complex insect chitin biosynthesis.

Choline transporter-like protein 2 interacts with chitin synthase 1 and is involved in insect cuticle development.

Chitin is an aminopolysaccharide present in insects as a major structural component of the cuticle. However, current knowledge on the chitin biosynthetic machinery, especially its constituents and mechanism, is limited. Using three independent binding assays, including co-immunoprecipitation, split-ubiquitin membrane yeast two-hybrid assay, and pull-down assay, we demonstrate that choline transporter-like protein 2 (Ctl2) interacts with krotzkopf verkehrt (kkv) in Drosophila melanogaster. The global knockdown of Ctl2 by RNA interference (RNAi) induced lethality at the larval stage. Tissue-specific RNAi to silence Ctl2 in the tracheal system and in the epidermis of the flies resulted in lethality at the first larval instar. The knockdown of Ctl2 in wings led to shrunken wings containing accumulated fluid. Calcofluor White staining demonstrated reduced chitin content in the first longitudinal vein of Ctl2 knockdown wings. The pro-cuticle, which was thinner compared to wildtype, exhibited a reduced number of chitin laminar layers. Phylogenetic analyses revealed orthologues of Ctl2 in different insect orders with highly conserved domains. Our findings provide new insights into cuticle formation, wherein Ctl2 plays an important role as a chitin-synthase interacting protein.

Design and Experimental Investigations of Shape and Attitude Carding System for the Wires of Micro Coreless Motor Winding.

The shape and attitude (S&A) of the electrode wire are important characteristics of micro coreless motor winding. The purpose of this paper is to present the design of a robotic micro-manipulation system for micro wire carding with arbitrary S&A, which can be used as the pretreatment system for wire micro-gripper systems. The system is based on the principle of flexible carding, and uses nylon, bristle, nanometer-silk and wool as materials for the brushing micro-manipulator. The trajectory of the brushing micro-manipulator is designed, and the S&A of the electrode wires are straightened through the combined motion mode of horizontal and vertical brushing micro-manipulators. The experimental results show that the material of the brushing micro-manipulator has a great impact on the carding quality. Nanometer-silk material is more suitable for horizontal brushing micro-manipulators, and wool material is more suitable for vertical brushing micro-manipulators. The geometric dimension of the brushing micro-manipulator also affects the carding quality. When the diameter is in the range of 1 mm, the carding effect of the horizontal brushing micro-manipulator with a length of 4.9-8 mm is better. The system can realize the automatic carding of flexible electrode wires with arbitrary S&A, and it will not damage the structure of wires in the process.

Orthogonality Measurement of Three-Axis Motion Trajectories for Micromanipulation Robot Systems.

In robotic micromanipulation systems, the orthogonality of the three-axis motion trajectories of the motion control systems influences the accuracy of micromanipulation. A method of measuring and evaluating the orthogonality of three-axis motion trajectories is proposed in this paper. Firstly, a system for three-axis motion trajectory measurement is developed and an orthogonal reference coordinate system is designed. The influence of the assembly error of laser displacement sensors on the reference coordinate system is analyzed using simulation. An approach to estimating the orthogonality of three-axis motion trajectories and to compensating for its error is presented using spatial line fitting and vector operation. The simulation results show that when the assembly angle of the laser displacement sensors is limited within a range of 10°, the relative angle deviation of the coordinate axes of the reference coordinate frame is approximately 0.09%. The experiment results show that precision of spatial line fitting is approximately 0.02 mm and relative error of the orthogonality measurement is approximately 0.3%.

Enhancing the Corrosion Resistance of Al-Cu-Li Alloys through Regulating Precipitation.

The influences of aging treatments on microstructures and the corrosion properties of an Al-Cu-Li alloy were investigated through an immersion test in intergranular corrosion (IGC) solutions, a potentiodynamic polarization test, and electrochemical impedance spectra (EIS), combined with scanning and transmission electron microscopy. The results demonstrated that the Al-Cu-Li alloy displayed outstanding comprehensive mechanical properties and IGC resistance after treating with pre-strain deformation and a double aging process (PDA). Both the PDA and pre-strain followed by creep aging (PCA) treatments significantly increased the number densities of T1 and θ' precipitates in the grain interior. The increase in precipitates in the grain interior greatly reduced the Cu-rich precipitates on the grain boundaries and inhibited the formation of a precipitate-free zone (PFZ). The electrochemical characteristics of the Al-Cu-Li alloy were influenced by the precipitates in the grain interior and grain boundaries. The studied alloy gained high IGC resistance due to the refinement of its microstructure, and the main corrosion mode was intra-granular pitting corrosion; thus, the corrosion diffusion rate was slowed down.

Enantioselective Total Syntheses of Pentacyclic Homoproaporphine Alkaloids.

Herein we report the first enantioselective total syntheses of pentacyclic homoproaporphine alkaloids by means of a route, which includes a tandem retro-oxa-Michael addition and nucleophilic substitution to generate the oxa-benzobicyclco[3.3.1]nonane core structure, a Pictet-Spengler cyclization to construct the fused B and C rings, and sequential Baeyer-Villiger oxidation and pinacol-type cyclization to install the hydroxyl-lactol moiety of D ring. With this unified route, six pentacyclic homoproaporphine alkaloids have been synthesized enantioselectively.

Identification and Validation of Reference Genes for Quantitative Gene Expression Analysis in Ophraella communa.

Ophraella communa is an effective bio-control agent of the invasive common weed. By now, the reference genes in O. communa have not yet been screened and validated. The aim of this study was to screen for the most stable reference genes in different backgrounds, such as different developmental stages, sexes, tissues, and male reproductive system with different body sizes. We selected 12 common housekeeping genes involved in different biological processes, including GAPDH, ACT1, ACT2, ARF1, ARF4, SDH, ßTUBC, RPL4, RPL19, RPS18, EF1α, and COX as the candidate reference genes. To analyze the stability of the candidate reference genes, we first used three dedicated algorithms, GeNorm, NormFinder, and BestKeeper, and further comprehensive ranking was provided by ReFinder. The results showed that RPL19 and RPL4 exhibited the least variation in different developmental stages/sexes and in male reproductive systems with different body sizes. COX proved to be most suitable for normalizing the gene expression levels in different tissues, and coincidentally, RPL19 was also found to be second in terms of stability in this study. To the best of our knowledge, this is the first study to identify suitable reference genes for analyzing gene expression in O. communa; thus, this study would lay the foundation for future research on the molecular physiology and biochemistry of O. communa and other insects.

Anti­inflammatory effect of ciclamilast in an allergic model involving the expression of PDE4B.

The present study aimed to investigate the potent inhibitory effects and possible biochemical basis of the novel phosphodiesterase 4 (PDE4) inhibitor ciclamilast, which is a derivative of piclamilast (RP 73401), on PDE4 and allergic inflammation. Ciclamilast was orally administered to allergic rats, their lungs and bronchoalveolar lavage fluid (BALF) were harvested, and their levels of inflammation and goblet cell hyperplasia, particularly cAMP­PDE activity, and expression and distribution of PDE4 subtypes were determined. The results suggested that oral administration of ciclamilast significantly reduced the total leukocyte number and eosinophil number in BALF and suppressed lung histology changes, including the infiltration of inflammatory cells into the perivascular and peribronchial spaces, structural changes and goblet cell hyperplasia. For eosinophil infiltration, ciclamilast exhibited improved selectivity compared with piclamilast. Furthermore, ciclamilast significantly inhibited the upregulated activity of cAMP­PDE and showed improved selective inhibition of the protein expression of PDE4B than piclamilast in a dose­dependent manner. The mRNA expression of PDE4D was significantly increased in allergic rats, but PDE4B was not. PDE4B was mainly distributed in the cytoplasm, whereas PDE4D was mainly distributed in the cell membrane. The improved anti­inflammatory activity of ciclamilast compared with piclamilast may be due to its higher level of inhibition of the activity, mRNA and protein expression of PDE4, particularly its effect on PDE4B.

[Immunoregulatory effects of pertussis protein on allergic asthma in mouse].

OBJECTIVE: To investigate the immunoregulatory effects of pertussis protein on airway inflammatory, IFN-gamma/IL-4 ratio in bronchoalveolar lavage fluids(BALF) and airway hyperresponsiveness (AHR) in the sensitized mice. METHODS: The sensitized mice were reexposed to ovalbumin and the airway response to methacholine injection was monitored. Inflammatory cells and cytokines IFN-gamma/IL-4 ratio in BALF were measured. Lung tissue specimens were collected for histological examination. RESULT: Intramuscular injection or intranasal instillation of pertussis protein inhibited changes in lung resistance and lung dynamic compliance, upregulated IFN-gamma/IL-4 ratio and decreased eosinophil accumulation in a dose-dependent manner. Pathological examination showed that goblet cell hyperplasia and inflammatory cells infiltration in lung tissue were suppressed by pertussis protein. CONCLUSION: Pertussis protein inhibits the inflammation and regulates the function of lungs in asthma mice, suggesting its potential application in treatment of asthma.

[Establishment and characteristics of acute lung injury model induced by cigarette smoke in ICR mice].

OBJECTIVE: To develop a mouse model of acute lung injury induced by cigarette smoke (CS) and to investigate inflammatory changes with the model. METHODS: ICR mice exposed to CS for 20-min, 3/d. Bronchoalveolar lavage fluid (BALF) and lung tissue were harvested at d 0, d 1, d 3 and d 7 after CS exposure. Neutrophil count in BAFL, TNF-alpha and MMP-12 levels, the activity of MPO in lung tissue were determined. RESULT: Neutrophil count in BALF, MMP-12 and MPO levels in lung tissue were increased after CS exposure in a time-dependent manner with a peak at d3. TNF-alpha level sharply increased at d1, and remained high level until d7. CONCLUSION: ICR mice are tolerant and sensitive to CS exposure, which may be used as an appropriate animal model for acute lung injury induced by cigarette smoke.