Role in post-translational modification of M2-type pyruvate kinase in tumorigenesis and development. / M2åž‹ä¸™é ®é ¸æ¿€é ¶ç¿»è¯‘åŽä¿®é¥°åœ¨è‚¿ç˜¤å‘ç”Ÿå’Œå‘å±•ä¸­çš„ä½œç”¨.

PKM2, also known as M2-type pyruvate kinase, has attracted significant attention due to its crucial role in glycolysis and its abnormal expression in various tumors. With the discovery of PKM2's non-metabolic functions, the transition between its pyruvate kinase activity (in the tetrameric form in the cytoplasm) and protein kinase activity (in the dimeric form in the nucleus) has once again made PKM2 a target of interest in cancer research. Studies have shown that PKM2 is a protein susceptible to various post-translational modifications, and different post-translational modifications play important regulatory roles in processes such as PKM2 cellular localization, structure, and enzyme activity conversion. In this review, we focused on the recent progress of multiple post-translational modifications of PKM2 and their important roles in tumor initiation and development. For example, phosphorylation and acetylation promote nuclear translocation by altering PKM2 cell localization; glycosylation and ubiquitination can promote the formation of dimer structure by affecting the structural transformation of PKM2; succinylation and redox modification promoted the enhancement of PKM2 kinase activity by affecting the transformation of kinase activity. Both changes affect the structure and cell localization of PKM2 and they play a role in promoting or inhibiting tumor development via altering its kinase activity.

Precise isolation and structural origin of an ultra-specific nanobody against chemical compound.

Highly specific antibodies are the key reagents for developing immunoassays with a low false positive rate for environmental monitoring. Here, we provide evidence that nanobodies have the potential to achieve higher specificity than conventional antibodies and explain why from their structural features. Using sulfadimethoxine (SDM) as a model analyte, we constructed an immune phage display library and precisely isolated an ultra-specific nanobody (H1-17) by a crucial homologous antigen counter selection strategy. H1-17 showed no observable cross-reactivity (CR) with other structural analogs of 41 SDM tested, which has never been achieved by conventional antibodies. The structurally original specificity of H1-17 was illuminated and compared with that of one conventional antibody by homology modeling and site-directed mutagenesis validation. It was found that the noncanonical disulfide bond (C50-C104) of H1-17 helped CDR3 form a tailor-made binding pocket and divide it into two parts to accommodate the common structure of sulfonamides and the characteristic methoxyl group of SDM, respectively. Besides, the mutual-checking hydrogen bonds also played important roles in the specific recognition. Lastly, immunoassays with zero false positive rate were developed to screen SDM in water and milk samples, indicating that nanobodies could be reliable reagents for the accurate detection of chemical compounds.

Functional characterization of knockdown resistance mutations in the plant bug, Apolygus lucorum Meyer-Dür.

Apolygus lucorum could cause severe economic damage to crops in China. The pest has been controlled by pyrethroids, and the target of pyrethroids is voltage-gated sodium channel (Nav). Double mutation (L1002F/D941G) was detected in a field-strain of A. lucorum . We found there was single mutation L1002F and double mutation L1002F/D941G, but no single mutation D941G in the field. The tail currents of L1002F and L1002F/D941G were reduced by two types pyrethroid. In contrast, D941G showed a similar activity as wild type channel. D941G and L1002F are both located in domain II but do not face the pyrethroid-binding pocket directly, suggesting that they might affect the insecticide-binding allosterically. L1002F/D941G has significantly different responses to pyrethroids compared to the wild type, but D941G alone has little effect compared to wild type. Our finding demonstrates that some mutation do not cause resistance by itself but can enhance the resistance combined with other mutations.

Unique post-translational modifications diversify the sodium channels in peach aphid (Myzus persicae [Sulzer]).

BACKGROUND: Myzus persicae (Sulzer), a worldwide pest, has caused remarkable damage to agriculture. Among the various control methods, chemical control (especially pyrethroids) is most commonly used. The targets of pyrethroids are voltage-gated sodium channels (Nav s). Unlike those of other insects, all Nav s of aphids (including two genes), such as Myzus persicae, are unique. RESULTS: In this study, three interlock patterns, I(918)-F(1014), L(918)-L(1014), and T(918)-F(1014), were found at sites 918 and 1014 in the sensitive Myzus persicae strain. Similar to that of other aphids, the Nav of Myzus persicae (MpNav ) consisted of two parts, that is MpNav -I and MpNav -II, which were embedded with an atypical 'DENS' ion selectivity filter and a conventional 'MFM' inactivation gate, respectively. MpNav had 11 alternative exons, including two mutually exclusive exons (k and l) and three exons (w, x, and t), which were located in domains I and III, respectively. In addition, various RNA editing events, A503T and V588A, appearing between the connection of domains I and II and the S3 of domain IV, respectively, had been described. CONCLUSION: Overall, MpNav was characterized by unique post-translational regulation mode, 918 and 1014 interlocks, and unusually alternative exons. Our research provides a new perspective on the evolution and variation of insect Nav s. © 2021 Society of Chemical Industry.

A Preliminary Toxicology Study on Eco-friendly Control Target of Spodoptera frugiperda.

Pyrethroid and indoxacarb are commonly used pesticides to control the fall armyworm (Spodoptera frugiperda) in the crops. There are a series of consequences caused by the use of pyrethroid and indoxacarb pesticides under emergency control, such as pest resistance development, contamination of soil, water, and farm products. This study analyzed the structure and physiological function of the sodium channel in S. frugiperda, which is an important step to elaborate the resistance mechanism of S. frugiperda to indoxacarb and pyrethroid pesticides. According to genetic analysis, the cloned cDNA sequences of sodium channel in S. frugiperda (SfNav) showed the shortest genetic distance with that of the sodium channel in Helicoverpa armigera. Under the induction of three pesticides, the expression of SfNav decreased in the first 12 h and then increased after 24 h. It was concluded that SfNav had a typical structure of the sodium channel of insects and its down-regulated expression can decrease the combination of S. frugiperda with pyrethroid and indoxacarb pesticides. The up-regulated expression of SfNav was conducive to the enhancement of the pesticide resistance.

Two classic mutations in the linker-helix IIL45 and segment IIS6 of Apolygus lucorum sodium channel confer pyrethroid resistance.

BACKGROUND: Pyrethroids are classified as type I and type II for distinct symptomology. Voltage-gated sodium channel is a primary target of pyrethroids. Mutations of the insect sodium channel have been identified to result in resistance to pyrethroids. Double mutation (L1002 F/M906 I) was detected in field-strain of Apolygus lucorum (Meyer-Dür). Although, it was illuminated the function of the same position mutation in other pests, it is necessary to demonstrate the role in A. lucorum . RESULTS: In this study, we examined the effects of mutations on channel gating and pyrethroid sensitivity in Xenopus oocytes. L1002 F, M906 I and L1002 F/M906 I all shifted the voltage dependence of activation in the depolarizing direction. L1002 F, M906 I and L1002 F/M906 I all reduced the amplitude of tail currents induced by type I (bifenthrin and permethrin) and type II (λ-cyhalothrin and deltamethrin). The double mutation, L1002 F/M906 I, reduced integral channel modification by 10-fold compared with the L1002 F and M906 I mutations alone, respectively. Computational analysis based on the model of dual pyrethroid receptors, the two resistance mutations, L1002 F and M906 I are facing two opposite sides of this newly identified pocket. Both mutations affect the optimal binding of the ligands by changing the shape of the pocket but in different ways. CONCLUSION: Our results illustrate the distinct effect of mutations on pyrethroids. It is predicted with computer modeling that these mutations allosterically affect pyrethroid binding. © 2020 Society of Chemical Industry.

Molecular characterization and functional expression of voltage-gated sodium channel variants in Apolygus lucorum (Meyer-Dür).

BACKGROUND: Apolygus lucorum (Meyer-Dür) is a serious worldwide agricultural pest, especially for Bt cotton in China. Pyrethroids, neonicotinoids and organophosphates are the most effective insecticides to control piercing and sucking insects, including A. lucorum. The voltage-gated sodium channel (Nav ) is major target site of pyrethroids. Extensive alternative splicing and RNA editing, two major post-transcriptional mechanisms, contribute to generate different functional sodium channel variants. In our research, we characterized the sodium channel variants of A. lucorum. RESULTS: In this study, we isolated numerous sodium channel variants that cover the entire coding region of the VGSC gene from A. lucorum. All clones could be grouped into 47 splice types based on the presence of nine alternative exons (exons j, n, o, a, p, b, s, q and t). Exons j, b and t were located independently, while exons n, o, a and p were located adjacently, as were exons s and q. We also found 35 nucleotide changes in different positions in individual variants, of which 18 nucleotide changes were A-to-I RNA editing, 11 nucleotide changes were likely due to U-to-C or C-to-U editing, and the others were likely natural sequence polymorphisms in the population. Furthermore, we expressed all of the variants in Xenopus oocytes. Eighteen of them were expressed in oocytes and sensitive to tetrodotoxin. CONCLUSION: Our results provide a functional basis for understanding how A. lucorum sodium channel variants work in regulating channel expression, pharmacology and gating properties for agricultural insects. Apolygus lucorum is widely distributed in cotton production. Our results suggest how AlNav (the sodium channel of A.lucorum) variants work in regulating channel expression, pharmacology and sodium channel gating for agricultural insects in the future. © 2020 Society of Chemical Industry.

Assessment of the effects of lethal and sublethal exposure to dinotefuran on the wheat aphid Rhopalosiphum padi (Linnaeus).

The wheat aphid Rhopalosiphum padi (Linnaeus) (Hemiptera: Aphididae) is a devastating pest of wheat crops worldwide. Dinotefuran, a novel neonicotinoid insecticide, has been used to prevent piercing-sucking agricultural insects, such as R. padi. This research showed that the dinotefuran not only caused direct mortality but also affected the physiology of R. padi via sublethal effects. In this study, residual film bioassay results indicated that there were no significant differences in the toxicity of dinotefuran between field in 2017 and laboratory strains. However, the longevity, fecundity and female preoviposition of the F0 generation were significantly decreased by exposure to different sublethal doses (L10, L20 and L30) of dinotefuran. In contrast, the fecundity and female preoviposition of the F1 generation were significantly increased by the sublethal treatment L20, although this dose reduced net reproductive rate, intrinsic rate of increase and finite rate of increase. These findings are the first laboratory evidence of hormesis attributable to low dinotefuran doses. Developmental duration of nymphs was significantly increased by the sublethal doses L20 and L30 but not L10. Sublethal exposure to dinotefuran can increase the transgenerational population growth of R. padi and affected demographic parameters of the target insect. This study provides useful data for developing management strategies for R. padi involving the use of dinotefuran.

Genome Analysis of Cytochrome in Dinotefuran-Treated Apolygus lucorum (Meyer-Dür).

In this study, two CYP genes, CYP395G1 and CYP4EY1, were analyzed in Apolygus lucorum (Hemiptera: Miridae). The expression pattern in different developmental stages of both CYP395G1 and CYP4EY1 revealed that first instar nymphs possessed the highest gene-transcript levels. After 12 h of dinotefuran treatments, the expression levels of CYP395G1 increased by 1.92-fold, while the CYP4EY1 expression decreased. It was observed that the sensitivities of dinotefuran to laboratory strains from F0 to F9 and the mRNA expression levels of CYP395G1 in the F9 dinotefuran selected strain were higher when compared to the control strain. The results suggest that CYP395G1 was possibly a candidate P450 that was involved in dinotefuran detoxification. The dinotefuran resistant strain of A. lucorum was difficult to increase, due to its special molecular structure of dinotefuran compared with other neonicotinoids.

Structural Health Monitoring of Above-Ground Storage Tank Floors by Ultrasonic Guided Wave Excitation on the Tank Wall.

There is an increasing interest in using ultrasonic guided waves to assess the structural degradation of above-ground storage tank floors. This is a non-invasive and economically viable means of assessing structural degradation. Above-ground storage tank floors are ageing assets which need to be inspected periodically to avoid structural failure. At present, normal-stress type transducers are bonded to the tank annular chime to generate a force field in the thickness direction of the floor and excite fundamental symmetric and asymmetric Lamb modes. However, the majority of above-ground storage tanks in use have no annular chime due to a simplified design and/or have a degraded chime due to corrosion. This means that transducers cannot be mounted on the chime to assess structural health according to the present technology, and the market share of structural health monitoring of above-ground storage tank floors using ultrasonic guided wave is thus limited. Therefore, the present study investigates the potential of using the tank wall to bond the transducer instead of the tank annular chime. Both normal and shear type transducers were investigated numerically, and results were validated using a 4.1 m diameter above-ground storage tank. The study results show shear mode type transducers bonded to the tank wall can be used to assess the structural health of the above-ground tank floors using an ultrasonic guided wave. It is also shown that for the cases studied there is a 7.4 dB signal-to-noise ratio improvement at 45 kHz for the guided wave excitation on the tank wall using shear mode transducers.

On the scattering of torsional waves from axisymmetric defects in buried pipelines.

This article develops a numerical model suitable for analysing elastic wave scattering in buried pipelines. The model is based on a previous so-called hybrid approach, where a nominally infinite length of pipe is split up into uniform and non-uniform regions. The key challenge for buried structures is in enforcing the appropriate boundary conditions in both the axial and radial directions, which must encompass the entire length of the structure, as well as the surrounding material. Accordingly, the focus of this article is on developing a model suitable for accurately applying these boundary conditions, and so the analysis is restricted here to the study of axisymmetric defects and to an incident sound field that consists of the fundamental torsional mode only. It is shown that this problem may be addressed in a numerically efficient way provided one carefully choses a perfectly matched layer for the surrounding material, and then integrates over this layer using a complex co-ordinate stretching function. This enables the use of mode matching to deliver a convergent system of equations that enforce the appropriate axial and radial boundary conditions.

[Clinical analysis of difficult intraarterial mechanical thrombectomy in patients with acute ischemic stroke].

OBJECTIVE: To investigate the causes and strategy of difficult intraarterial mechanical thrombectomy (≥3 times) in patients with acute ischemic stroke (AIS). METHODS: The clinical data of 8 cases of AIS with thrombectomy ≥3 times admitted in Department of Neurology, the 306(th) Hospital of People's Liberation Army from June to October in 2015 was analyzed retrospectively. There were 7 male and 1 female patients, aged from 38 to 86 years with an average age of (70±15) years, in which 5 cases were cardiogenic cerebral embolism and 3 cases were large artery atherosclerotic infarction. The National Institute of Health stroke scale (NIHSS) score (M (QR)) was 16 (12) before procedure and modified thrombolysis in cerebral infarction (mTICI)score were 0 in all the patients. Solitaire AB was used in thrombectomy in the occlusion of the arteries. RESULTS: The causes of difficult intraarterial thrombectomy included multiple thrombus, tortuosity in vascular paths, guiding catheter being placed below the internal carotid artery siphon leading to weak strength of suction and support of stent, embolus dropping in the thrombectomy and inadequate anesthesia. After successful thrombectomy 3 cases had mTICI score of 2a, 4 cases of 2b, 1 case of 3. The NIHSS score was 5 (24) at 7(th) day after treatment. At the 90-day follow-up 5 patients had good prognosis (modified Rankin score 0 to 2) and 3 had disability (modified Rankin score 3 to 4). CONCLUSION: Cases of AIS with difficult intraarterial thrombectomy can be treated by improving thrombectomy materials and technique, reasonable anesthesia and perioperative medication in decision-making strategy.

On the scattering of elastic waves from a non-axisymmetric defect in a coated pipe.

Viscoelastic coatings are often used to protect pipelines in the oil and gas industry. However, over time defects and areas of corrosion often form in these pipelines and so it is desirable to monitor the structural integrity of these coated pipes using techniques similar to those used on uncoated pipelines. A common approach is to use ultrasonic guided waves that work on the pulse-echo principle; however, the energy in the guided waves can be heavily attenuated by the coating and so significantly reduce the effective range of these techniques. Accordingly, it is desirable to develop a better understanding of how these waves propagate in coated pipes with a view to optimising test methodologies, and so this article uses a hybrid SAFE-finite element approach to model scattering from non-axisymmetric defects in coated pipes. Predictions are generated in the time and frequency domain and it is shown that the longitudinal family of modes is likely to have a longer range in coated pipes when compared to torsional modes. Moreover, it is observed that the energy velocity of modes in a coated pipe is very similar to the group velocity of equivalent modes in uncoated pipes. It is also observed that the coating does not induce any additional mode conversion over and above that seen for an uncoated pipe when an incident wave is scattered by a defect. Accordingly, it is shown that when studying coated pipes one need account only for the attenuation imparted by the coating so that one may normally neglect the effect of coating on modal dispersion and scattering.

Measurement of complex acoustic intensity in an acoustic waveguide.

Acoustic intensity is normally treated as a real quantity, but in recent years, many articles have appeared in which intensity is treated as a complex quantity where the real (active) part is related to local mean energy flow and the imaginary (reactive) part to local oscillatory transport of energy. This offers the potential to recover additional information about a sound field and then to relate this to the properties of the sound source and the environment that surrounds it. However, this approach is applicable only to multi-modal sound fields, which places significant demands on the accuracy of the intensity measurements. Accordingly, this article investigates the accuracy of complex intensity measurements obtained using a tri-axial Microflown intensity probe by comparing measurement and prediction for sound propagation in an open flanged pipe. Under plane wave conditions, comparison between prediction and experiment reveals good agreement, but when a higher order mode is present, the reactive intensity field becomes complicated and agreement is less successful. It is concluded that the potential application of complex intensity as a diagnostic tool is limited by difficulties in measuring reactive intensity in complex sound fields when using current state of the art acoustic instrumentation.

A hybrid finite element approach to modeling sound radiation from circular and rectangular ducts.

A numerical model based on a hybrid finite element method is developed that seeks to join sound pressure fields in interior and exterior regions. The hybrid method is applied to the analysis of sound radiation from open pipes, or ducts, and uses mode matching to couple a finite element discretization of the region surrounding the open end of the duct to wave based modal expansions for adjoining interior and exterior regions. The hybrid method facilitates the analysis of ducts of arbitrary but uniform cross section as well the study of conical flanges and here a modal expansion based on spherical harmonics is applied. Predictions are benchmarked against analytic solutions for the limiting cases of flanged and unflanged circular ducts and excellent agreement between the two methods is observed. Predictions are also presented for flanged and unflanged rectangular ducts, and because the hybrid method retains the sparse banded and symmetric matrices of the traditional finite element method, it is shown that predictions can be obtained within an acceptable time frame even for a three dimensional problem.