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IntroductionResponse regulators from diverse two-component systems often function as diguanylate cyclases or phosphodiesterases, thereby enabling precise regulation of intracellular c-di-GMP levels to control bacterial virulence and motility. However, the regulatory mechanisms of c-di-GMP require further elucidation.MethodsThis study confirmed that ArrS and ArrR form a two-component system via structural analysis, two-hybrid, and phosphodiesterase activity detection. To evaluate the impact of ArrS/ArrR on intracellular c-di-GMP levels, biofilm detection, motility detection, fluorescence reporter plasmids, and LC-MS/MS analysis were employed. One-hybrid, EMSA, and RT-qPCR were used to demonstrate the function of ArgR on arrSR promoter. The roles of ArrS/ArrR in Aeromonas veronii were investigated using RT-qPCR, murine model, and proteomics.ResultsArrS and ArrR constituted a two-component system in Aeromonas veronii and were transcriptionally repressed by ArgR. ArrR exhibited phosphodiesterase activity, which is inhibited through phosphorylation mediated by ArrS. In Aeromonas veronii, ArrS/ArrR significantly altered the intracellular c-di-GMP levels. In a murine model, ΔarrS exhibited increased pathogenicity, leading to elevated TNF-α and IFN-γ levels in serum, and severer toxicity to spleen and kidney. These effects might be elucidated by the upregulated inflammation-associated proteins in ΔarrS. Moreover, the exonuclease RecB was also up-regulated in ΔarrS.DiscussionWe elucidated the regulatory mechanism of ArrS/ArrR on intracellular c-di-GMP levels and its impact on the virulence in Aeromonas veronii, and discussed the intricate relationship between c-di-GMP metabolism and arginine metabolism.

PurposeThis study aimed to explore the effects of neural and muscular factors on lower limb explosive strength in male college sprinters, and build models based on those factors to identify the key neuromuscular factors that predict the rate of force development (RFD) and 30 m sprint time.Method15 male college sprinters were recruited in this study, with 100 m personal best times under 10.93 s. The neuromuscular data were collected by H-reflex and V-wave, isokinetic muscle strength, vertical jumps, and 30 m sprint tests. Pearson correlation and multiple stepwise regression were used for data analysis. The level of statistical significance was set at p ≤ 0.05 for all analyses.Results30 m sprint time had a significant moderate positive correlation with Achilles tendon stiffness (r = 0.50, p = 0.05, 95%CI: 0.01–0.81) and a significant moderate negative correlation with the H-index (r = −0.54, p = 0.04, 95%CI: 0.82 to −0.03), V wave (V/MmaxA, r = −0.59, p = 0.02, 95%CI: 0.85 to −0.11) and the eccentric strength of Hamstring (HECC, r = −0.53, p = 0.04, 95%CI: 0.82 to −0.03). The rate of force development (RFD) had a significant positive correlation with H reflex (Hmax/Mmax, r = 0.57, p = 0.03.95%CI:0.08–0.84), and the eccentric strength of Quadriceps (QECC, r = 0.53, p = 0.04, 95%CI: 0.02–0.82). V/MmaxA and HECC were identified as predictors of 30 m sprint time, and the R2 explained 57.5% of the variance. Vertical stiffness and QECC explained 82.7% of the variation in the RFD.ConclusionThis study found that V/MmaxA and HECC were predictive factors of 30 m sprint time, vertical stiffness and QECC were the predictive factors of RFD. Neural factors such as the α-motoneurons excitability of the spinal and supraspinal centers, have a greater influence on lower limb explosive strength in male college sprinters. Therefore, training related to the neural function of sprinters should be emphasized. In addition, H reflex and V wave can be used widely to assess and monitor the neural function of sprinters in future research. The impact of neural drive on muscles in different levels and sexes of sprinters, and the neuromuscular modulation during muscle contractions can be further explored.

Ochratoxin A (OTA) is a common fungal toxin frequently detected in food and human plasma samples. Currently, the physiologically based toxicokinetic (PBTK) model plays an active role in dose translation and can improve and enhance the risk assessment of toxins. In this study, the PBTK model of OTA in rats and humans was established based on knowledge of OTA-specific absorption, distribution, metabolism, and excretion (ADME) in order to better explain the disposition of OTA in humans and the discrepancies with other species. The models were calibrated and optimized using the available kinetic and toxicokinetic (TK) data, and independent test datasets were used for model evaluation. Subsequently, sensitivity analyses and population simulations were performed to characterize the extent to which variations in physiological and specific chemical parameters affected the model output. Finally, the constructed models were used for dose extrapolation of OTA, including the rat-to-human dose adjustment factor (DAF) and the human exposure conversion factor (ECF). The results showed that the unbound fraction (Fup) of OTA in plasma of rat and human was 0.02–0.04% and 0.13–4.21%, respectively. In vitro experiments, the maximum enzyme velocity (Vmax) and Michaelis–Menten constant (Km) of OTA in rat and human liver microsomes were 3.86 and 78.17 μg/g min−1, 0.46 and 4.108 μg/mL, respectively. The predicted results of the model were in good agreement with the observed data, and the models in rats and humans were verified. The PBTK model derived a DAF of 0.1081 between rats and humans, whereas the ECF was 2.03. The established PBTK model can be used to estimate short- or long-term OTA exposure levels in rats and humans, with the capacity for dose translation of OTA to provide the underlying data for risk assessment of OTA.

Abstract The tropopause region is crucial for the stratosphere‐troposphere exchange (STE) and acts as an indicator of climate change. Double tropopauses (DTs) act to increase the STE process but their driving mechanisms remain an open question. The present assessment offers for the first time the linkage between tropospheric gravity waves (GWs) and DT events by exploring a global data set of multi‐year radiosonde measurements. In the extratropics, the occurrence frequency of DT events keeps a remarkably consistent spatial‐temporal structure with GW total energy. Under the DT scenario, GW total energy has increased by 37.67% compared to single tropopause events. Based on a statistical assessment, the upward propagating GWs throughout the second tropopause region can probably raise Kelvin‐Helmholtz instability or turbulence, leading permanent irregularities in thermodynamic structure, and consequently, increasing the likelihood of DT.

Abstract Background To investigate the pharmacokinetics of 6-O-demethylmenisporphine, an oxoisoaporphine alkaloid with significant anti-tumor activities and isolated from Menispermi Rhizoma, a novel and sensitive HPLC assay was established for 6-O-demethylmenisporphine quantification in rat plasma. Methods Peak responses were detected by a highly selective and sensitive fluorescence detector with 426-nm excitation and 514-nm emission wavelengths. Curcumin was employed as the internal standard (IS). A Capcell Pak C18 column (150 mm × 4.6 mm i.d., 5 μm) and an isocratic elution procedure with a flow rate of 1.0 mL/min were used to exclude the endogenous interfering substance. Acetonitrile-water (68:32, v/v) containing 1% formic acid was employed as mobile phase. A 7-point calibration curve that covered the concentration range of 10–2500 ng/mL was constructed. Results A good linearity was observed with a correlation coefficient (r) of 0.9993. The lower limit of quantification for 6-O-demethylmenisporphine was 10 ng/mL. The mean recoveries of analyte in rat plasma exceeded 80.5%. The precision at four concentration levels was within 11.3% and the accuracy ranged from − 7.6 to 6.7%. Conclusion Using this new HPLC-FLD method, the investigation of plasma samples from rats following oral dosing of neat compound and Menispermi Rhizoma extract was successfully conducted. The results will provide a reference for the evaluation of preclinical safety of 6-O-demethylmenisporphine.

Abstract Background Renal artery aneurysms (RAAs) are rare and usually asymptomatic, and some RAAs can be associated with calcifications, which may lead to misdiagnoses as renal calculi, which are then mistakenly treated. Case presentation A 69-year-old female patient was admitted to the hospital with no discomfort and was diagnosed with a large right renal calculus. The ultrasound and computed tomography urography (CTU) scan suggested a large calculus in the right pelvis with hydrops of the kidney. Therefore, we chose percutaneous nephrolithotomy (PCNL) to treat the right renal calculus, but no calculi were found in the renal pelvis. When we removed the mucosa of the renal pelvis with a holmium laser, we observed a fluctuating unruptured aneurysm with calcification. Therefore, the previous diagnosis of a renal calculus was disregarded. The operation was stopped immediately, and then computed tomography (CT) angiography was performed, confirming the right renal aneurysm with calcification. Then, Renal artery aneurysm (RAA) coil embolization was performed. After a long-term follow-up, the patient recovered well. Conclusions The RAA of this patient had calcific changes, which led us to errors in the diagnosis. Hence, it is very important for surgeons to effectively distinguish between renal calculi and aneurysms with ring-like calcifications. Our case report looks back at the thrilling situation during the operation and advises surgeons on how to deal with this situation properly.

Background: Myocardial ischemia (MI) is a leading cause of death worldwide. Menispermi Rhizoma is a traditional Chinese medicine that exerts a variety of beneficial pharmacological activities in many diseases, including MI.Purpose: Serum pharmacochemistry and network pharmacology were used to explore the material basis and mechanism of action of Menispermi Rhizoma against MI.Methods: The absorbed components of Menispermi Rhizoma in rat plasma were analyzed by ultra-performance liquid chromatography quadrupole time-of-flight tandem mass spectrometry (UPLC-Q-TOF/MS). The key components, targets, pathways, and interrelated information were obtained by network pharmacology. The potential effective components of Menispermi Rhizoma against MI were screened by methyl-thiazolyl-tetrazolium (MTT) assay, and the cardioprotective effect and mechanism of active components were verified by Western blotting and molecular docking.Results: In total, 25 absorbed components of Menispermi Rhizoma in plasma were identified. Network pharmacology revealed 81 major targets of Menispermi Rhizoma against MI, mainly involving the regulation of the PI3K/AKT and MAPK pathways. In vitro validation of H9c2 cells revealed that acutumine, daurisoline, dauricoside, and 6-O-demethylmenisporphine are the main bioactive components of Menispermi Rhizoma. The levels of lactate dehydrogenase, creatine kinase, and malondialdehyde (MDA) were significantly decreased by four alkaloids, whereas the activities of superoxide dismutase (SOD) and glutathione (GSH) were significantly increased. Four alkaloids effectively protected H9c2 cells against OGD-induced apoptosis by Hoechst/PI staining and flow cytometry assay. Western blotting results showed that the four alkaloids upregulated the expression ratio of Bcl-2/Bax and downregulated the expression levels of Cyt-C and cleaved caspase 3, which further supported the anti-cardiomyocyte apoptosis and antioxidative stress effect of Menispermi Rhizoma. Molecular docking confirmed that the four compounds were capable of binding to AKT1, MAPK1, EGFR, CASP3, and MAPK8 proteins, suggesting the protective effect of Menispermi Rhizoma on MI via PI3K/AKT, MAPK, and apoptosis pathways.Conclusion: Menispermi Rhizoma exerted cardioprotective effects through the effect characteristics: multiple-ingredient, multi-target, and multi-pathway. This research provided a reference for further mechanistic research on wider applications of Menispermi Rhizoma for MI treatment.

Sarcopenia caused by aging is an important factor leading to a decline in the quality of life of older people. Apoptosis in muscle atrophy accelerates the process of muscle loss in older populations. The present study aimed to investigate the effects of 32 weeks of high-intensity interval training (HIIT) and resistance training (RT) on the skeletal muscle-related indices and provide a theoretical basis for regulating the mitochondrial-mediated pathway to delay sarcopenia. We randomly selected 10 from eight-month-old male SD rats (N = 130) as the baseline group; after 1 week of adaptive feeding, the rats were sacrificed. The remaining rats were randomly assigned to one of three groups: control group (C, N = 40, natural aging for 32 weeks), HIIT group (H, N = 40, performed six loops of 3 min at 90% and 3 min at 50% VO2 max speed treadmill running, with 5 min at 70% VO2 max speed at the beginning and the end of the training, 3 times a week for 32 weeks), and resistance group (R, n = 40, 46 min per day, 3 days per week, with a 30% maximum load on a treadmill with a slope of 35°, 15 m/min). The soleus muscles were collected for analysis at baseline and every 8 weeks. Aging resulted in decreased soleus muscle mass and Bcl-2 levels in the mitochondria, while the levels of reactive oxygen species (ROS) and Bax did not change. HIIT reversed the age-associated activation of pro-apoptotic processes, but RT did not. In addition, when rats were aged from 8 to 16 months, the level of Cyt-C did not change, the Caspase-9 levels and Caspase-3 levels decreased gradually in the soleus muscles, the rats of both the HIIT and RT groups had these indices decreased at 32 weeks. The results suggest that the age-associated loss of muscle mass was reversed by training, and the effect of RT was better than that of HIIT. Both the HIIT and RT rats showed a decrease in the apoptosis of skeletal muscle cells after 32 weeks of intervention. HIIT performed better for long-term intervention regarding the pro-apoptotic factors. This study warranted further research to delineate the underlying mechanism of effects of different exercise methods on the changes of aging skeletal muscle at in vivo level.

Mycoplasma hyorhinis is a common pathogen of swine and is also associated with various human tumors. It causes systemic inflammation, typically polyserositis and polyarthritis, in some infected pigs. However, the pathogenic mechanism of M. hyorhinis remains unclear. DnaK is a highly conserved protein belonging to the heat-shock protein 70 family of molecular chaperones, which plays important roles as a moonlighting protein in various bacteria. In the present study, we identified the surface exposure of M. hyorhinis DnaK. Two virulent strains expressed more DnaK on their surface than the avirulent strain. Thereafter, the potential moonlighting functions of DnaK were investigated. Recombinant M. hyorhinis DnaK (rMhr-DnaK) was found to be able to adhere to swine PK-15 cells and human NCI-H292 cells. It also bound to four extracellular matrix components—fibronectin, laminin, type IV collagen, and vitronectin—in a dose-dependent manner. ELISA demonstrated an interaction between rMhr-DnaK and plasminogen, which was significantly inhibited by a lysine analog, ε-aminocaproic acid. rMhr-DnaK-bound plasminogen was activated by tissue-type plasminogen activator (tPA), and the addition of rMhr-DnaK significantly enhanced the activation. Finally, a DnaK-specific antibody was detected in the serum of pigs immunized with inactivated vaccines, which indicated good immunogenicity of it. In summary, our findings imply that DnaK is an important multifunctional moonlighting protein in M. hyorhinis and likely participates extensively in the infection and pathogenesis processes of M. hyorhinis.

Abstract Background To compare the imaging parameters pre- and post- reductive procedure for atlantoaxial dislocation via posterior fixation using pedicle screw and rod. Methods Thirty-seven patients suffering from atlantoaxial dislocation underwent posterior reduction and internal fixation by pedicle screw and rod. We measured pre-operative and post-operative atlantodental interval (ADI), clivus-canal angle (CCA), cervicomedullary angle (CMA), sum of lateral mass interspace (SLMI) of the operation and the control group. ADI, CCA, CMA, and SLMI between the pre-operative and post-operative conditions of the operation group and the control group were compared. Results The ADI, CCA, CMA, and SLMI in the pre-operative condition of the operation group were 8.3 ± 4.3 mm, 130.2 ± 14.2°, 133.8 ± 16.7°, and 3.7 ± 1.3 mm, respectively, those in the post-operative condition of the operation group were 1.0 ± 0.9 mm, 148.5 ± 9.4°, 156.0 ± 8.2°, and 8.0 ± 2.7 mm, respectively, while those in the control group were 1.2 ± 0.3 mm, 152.7 ± 5.3°, 160.2 ± 6.3°, and 4.5 ± 1.0 mm respectively. Post-operative ADI, CCA, CMA, and SLMI were statistically different (p

Abstract Background Asian citrus psyllid (ACP) is the primary vector responsible for the transmission of the phloem-limited bacteria Candidatus Liberibacter spp., associated with huanglongbing (HLB), which causes great loss to the citrus industry. Although the roles of leaf color and volatile compounds in the orientation of ACP have been proven, the quantification of color and allelochemicals in the host plant are kept unclear, especially in wild citrus germplasms. Results Chongyi wild mandarin significantly attracted more ACP than wild Hong Kong kumquat, ‘Gannan zao’ navel orange and orange jasmine did in the four-choice and olfactometer assays. The color parameters of the tender leaves from Chongyi wild mandarin and ‘Gannan zao’ were similar. The yellow color in both of them was less saturated than that of the other two plants species, but Chongyi wild mandarin had significant lower carotenoid content (P < 0.05). Notably metabolic profiling differences were observed among the healthy tender shoots from the four tested plants via UPLC-QQQ-MS and GC-MS analyses. Comparing with the other three plant species, 66 and 50 metabolites with significantly different contents in Chongyi wild mandarin were selected as UPLC-identified and GC-identified metabolites of interest (P < 0.05), respectively. Flavonoids accounted for a large group of secondary metabolites of interest, which may function as stimulants or repellents of ACP. Higher content of salicylic acid o-hexoside and lower content of (+)-jasmonic acid in Chongyi wild mandarin may lead to higher amount of methyl salicylate (an ACP attractant) and lower amount of trans-ocimene (an attractant to herbivores’ natural enemies) as well as the suppression of JA-mediated wounding response. This kind of synergistic or antagonistic effect among the metabolites differentially accumulated in Chongyi wild mandarin made it a more attractive host plant to ACP. Conclusions Less saturated yellow color, high amount of attractants, low amount of repellents and insensitivity of JA-mediated wounding response are the four possible reasons why Chongyi wild mandarin attracted more ACP. This work may shed light on the olfactory and visual response of ACP to wild citrus germplasm hosts, and suggest the feasibility of developing ACP attractants or repellents patterned on potential metabolites.

A novel post-treatment process was employed to seal a plasma-sprayed Al₂O₃-13wt. %TiO₂ (AT13) coating to improve its corrosion resistance. A series of AT13 coatings were sealed with silicone resin using conventional sealing and ultrasonic sealing at different temperatures. The effect of the sealing treatment on the corrosion behaviours of the coatings were investigated with salt spray tests and electrochemical methods. Most of the ultrasonic sealed coatings had less weight loss than conventional sealed coatings after the salt spray test. In 5.0 wt. % NaCl solutions, the ultrasonic sealed coating had the higher corrosion potential and the lower corrosion current density. The coating sealed at 40℃ has the lowest corrosion weight loss, lowest corrosion current densities and highest corrosion potential, compared with conventional sealed coating. It means that ultrasonic sealing can improve the corrosion resistance of plasma-sprayed AT13 coating effectively and the temperature was a key factor in the sealing treatment.

The regional ecological risk model is built to predict the regional ecological risk level more accurately by using principal component analysis and optimizing standard BP neural network. Taking Xiangxi Tujia and Miao Autonomous Prefecture as an example, twelve primary factors affecting regional risk are selected. The sample data are processed by principal component analysis. The obtained main components are then used as input factors of the improved BP neural network, and the level of ecological risk is used as output factor. The results indicate that the error between the expected output and the actual output is 4.36% in 2016, 1.08% in 2017, and 5.18% in 2018, respectively, with all controlled within 6%. Compared with the prediction accuracy made by standard BP neural network without principal component analysis, the prediction accuracy made by improved BP neural network with principal component analysis is greatly improved. This comprehensive prediction model provides a better evaluation method for prediction of ecological risk level.

This work investigates life cycle costing analysis as a tool to estimate the cost of hydrogen to be used as fuel for Hydrogen Fuel Cell vehicles (HFCVs). The method of life cycle costing and economic data are considered to estimate the cost of hydrogen for centralised and decentralised production processes. In the current study, two major hydrogen production methods are considered, methane reforming and water electrolysis. The costing frameworks are defined for hydrogen production, transportation and final application. The results show that hydrogen production via centralised methane reforming is financially viable for future transport applications. The ownership cost of HFCVs shows the highest cost among other costs of life cycle analysis.

Prion protein PrP is a central player in several devastating neurodegenerative disorders, including mad cow disease and Creutzfeltd-Jacob disease. Conformational alteration of PrP into an aggregation-prone infectious form PrPSc can trigger pathogenic events. How levels of PrP are regulated is poorly understood. Human PrP is known to be degraded by the proteasome, but the specific proteolytic pathway responsible for PrP destruction remains elusive. Here, we demonstrate that the ubiquitin ligase gp78, known for its role in protein quality control, is critical for unglycosylated PrP ubiquitylation and degradation. Furthermore, C-terminal sequences of PrP protein are crucial for its ubiquitylation and degradation. Our study reveals the first ubiquitin ligase specifically involved in prion protein PrP degradation and PrP sequences crucial for its turnover. Our data may lead to a new avenue to control PrP level and pathogenesis.

In the three-dimensional tetrachlorophthalate-bridged title complex [Er(C8Cl4O4)(H2O)7](C8HCl4O4)·C8H2Cl4O4·H2O, the ErIII ion is coordinated in form of a distorted square antiprism by an O atom of a tetrachlorophthalate ligand and by seven water O atoms. Extensive hydrogen bonds establish a layered network structure extending parallel to (001).

The soil slurry transfer methods (e.g. transferring soil slurry when it was continuously agitating or reached standing state) for extracellular enzyme activity (EEA) measurement are still different. Whether the result of EEAs is consistent between the two transfer methods remains unclear and needs to be tested. This research aimed to estimate the impact of transfer methods on EEA under different environmental conditions. Surface soil was collected in different growth stages of winter wheat. The winter wheat field was located in a free air carbon dioxide enrichment (FACE) platform in Changping district of Beijing. The FACE platform included two CO2 concentrations, which were ambient CO2 concentration (420±15μmol·mol-1) and elevated CO2 concentration (550±15μmol·mol-1), respectively. Seven EEAs were chosen to study the influence of different transfer methods under different CO2 concentrations. The results showed that the EEAs were significantly higher under agitating state than standing state. It might be attributed to the fact that soil slurry under agitating state contained more soil particles, which were easily to absorb extracellular enzymes. The extent of influence of transfer methods on EEA varied among different enzymes. To be specific, the carbon (C) and phosphorus (P) acquiring enzyme activities were strongly influenced by transfer methods, showing a significant increase of 191.45% to 774.09% under agitating state compared to standing state, while the nitrogen (N) acquiring enzyme activity only showed an increase of 6.66% to 30.59% under agitating state compared to standing state. The transfer methods also led to different responses of enzyme activities to elevated CO2. Most enzyme activities showed no response to elevated CO2 under the agitating state. By contrast, more enzyme activities decreased significantly in response to elevated CO2 under the standing state. Furthermore, the calculated extracellular enzymatic stoichiometry and vector characteristic both indicated that microbial resource limitation was unchanged by elevated CO2 under agitating state. However, under the standing state elevated CO2 reduced microbial C limitation and enhanced microbial N limitation. This study provided valid evidence that transfer methods had a distinguished impact on enzyme activities, extracellular enzyme stoichiometry, vector characteristic, and their response to elevated CO2. Consequently, the result of microbial resource limitation under elevated CO2 differed between the two transfer methods. Based on this, authors strongly suggest to unify the transfer method to reduce study uncertainty. [ABSTRACT FROM AUTHOR]