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It is expected that the activity of photocatalysts can remain the same or decrease as little as possible in photocatalysis reaction. Herein, for the first time, a self‐accelerating H2 production activity in a noble‐metal‐free Cu2O/TpPa‐2‐COF photocatalyst is reported. It shows a beginning H2 production rate of 4.41 mmol h−1 g−1 under visible light illuminance, while the activity kept increasing to 27.27 mmol h−1 g−1 after 25 h reaction, which is 6.2 times higher than the beginning activity and reaches a record high. It is confirmed that part of Cu2O in Cu2O/TpPa‐2‐COF in situ transformed to Cu0 in photocatalytic reaction, which acting as cocatalyst promotes the separation of photogenerated charge carriers. Further density functional theory calculations demonstrate that the Schottky barrier height of Cu‐Cu2O (111) interface is much smaller than that of Pt‐Cu2O (111), supporting its more efficient effect than that with Pt as cocatalyst. [ABSTRACT FROM AUTHOR]

Designing photocatalysts with efficient charge separation and electron transport capabilities to achieve efficient visible-driven hydrogen production remains a challenge. Herein, 2D–2D conductive metal–organic framework/g-C3N4 heterojunctions were successfully prepared by an in situ assembly. Compared to pristine g-C3N4, the ratio-optimized Ni-CAT-1/g-C3N4 exhibits approximately 3.6 times higher visible-light H2 production activity, reaching 14 mmol g−1. Through investigations using time-resolved photoluminescence, surface photovoltage, and wavelength-dependent photocurrent action spectroscopies, it is determined that the improved photocatalytic performance is attributed to enhanced charge transfer and separation, specifically the efficient transfer of excited high-energy-level electrons from g-C3N4 to Ni-CAT in the heterojunctions. Furthermore, the high electrical conductivity of Ni-CAT enables rapid electron transport, contributing to the overall enhanced performance. This work provides a feasible strategy to construct efficient dimension-matched g-C3N4-based heterojunction photocatalysts with high-efficiency charge separation for solar-driven H2 production. [ABSTRACT FROM AUTHOR]

The COVID-19 pandemic, caused by SARS-CoV-2, has led to over 750 million infections and 6.8 million deaths worldwide since late 2019. Due to the continuous evolution of SARS-CoV-2, many significant variants have emerged, creating ongoing challenges to the prevention and treatment of the pandemic. Therefore, the study of antibody responses against SARS-CoV-2 is essential for the development of vaccines and therapeutics. Here we perform single particle cryo-electron microscopy (cryo-EM) structure determination of a rabbit monoclonal antibody (RmAb) 9H1 in complex with the SARS-CoV-2 wild-type (WT) spike trimer. Our structural analysis shows that 9H1 interacts with the receptor-binding motif (RBM) region of the receptor-binding domain (RBD) on the spike protein and by directly competing with angiotensin-converting enzyme 2 (ACE2), it blocks the binding of the virus to the receptor and achieves neutralization. Our findings suggest that utilizing rabbit-derived mAbs provides valuable insights into the molecular interactions between neutralizing antibodies and spike proteins and may also facilitate the development of therapeutic antibodies and expand the antibody library. • Cryo-EM structure of the WT spike-9H1 complex explains its potent binding mode. • The antibody-bound spike structures reveal the neutralizing mechanism for 9H1. • Structure comparison reveals the sensitivity of antibodies to mutations. • RmAb 9H1 highlights the potential of screening antibodies from different species. [ABSTRACT FROM AUTHOR]

For on-orbit repair and space debris removal missions, a collision-free trajectory to the target is to be planned in a dynamically changing environment. Although such a trajectory can be learned in a ground simulator through repetitive trials, the established environment is often of limited precision due to space perturbations and measurement errors. Considering possible discrepancies between simulation and the real world, a tunnel, instead of a single trajectory, should be learned on the ground. In this paper, a robust planning method based on Q-learning is proposed for space missions with a priori environment information of limited precision. Based on a specific on-orbit repair scenario, reward functions in accordance with the multiple mission objectives are designed. The trajectories learned under different parameter randomization settings are combined and a robust tunnel is generated in the discrete grid world. By keeping the spacecraft inside the tunnel in the actual mission, collisions with the dynamic obstacles would be avoided and the goal of target rendezvous would be achieved. At last, a numerical simulation is carried out and the proposed method is validated under both nominal and randomized conditions. • Q-learning is utilized to find a safe trajectory to the target in space missions. • Reward functions taking into account multiple mission objectives are designed. • Possible discrepancies between simulation and the real world are considered. • A collision-free trajectory tunnel is learned with guaranteed robustness. • Both nominal and randomized conditions are validated in the simulation. [ABSTRACT FROM AUTHOR]

Realization of solar‐driven aerobic organic transformation under atmospheric pressure raises the great challenge for efficiently activating O2 by tailored photocatalysts. Guided by theoretical calculation, phosphate groups are used to induce the construction of ultrathin Co phthalocyanine/g‐C3N4 heterojunctions (CoPc/P‐CN, ≈4 nm) via strengthened H‐bonding interfacial connection, achieving an unprecedented 14‐time photoactivity improvement for UV–vis aerobic 2,4‐dichlorophenol degradation compared to bulk CN by promoted activation of O2. It is validated that more •O2− radicals are produced through the improved photoreduction of O2 by accelerated photoelectron transfer from CN to the ligand of CoPc and then to the abundant single Co–N4 (II) catalytic sites, as endowed by the matched dimension, intimate interface even at the molecular level, and high CoPc dispersion of resulted heterojunctions. Interestingly, CoPc/P‐CN also exhibits outstanding photoactivities in the aerobic oxidation of aromatic alcohols. This work showcases a feasible route to realize efficient photocatalytic O2 activation by exploiting the potential of ultrathin metal phthalocyanine (MPc) assemblies with abundant single‐atom sites. More importantly, a universal facile strategy of H‐bonding‐dominating construction of MPc‐involved heterojunctions is successfully established. [ABSTRACT FROM AUTHOR]

In this paper the observability of bearing-only tracking is analyzed and the trajectory optimization algorithms to enhance the observability during the rendezvous are presented. Firstly, the relative dynamic model and measurement model are established, and the necessary and sufficient condition for observability when maneuvering is determined using the pseudo linear method. Then, the observability indices, such as the filter covariance matrix trace and the Fisher information matrix (FIM) determinant, are combined with the fuel consumption index to optimize the approaching trajectory. In order to keep the line-of-sight (LOS) aligned with the target and to ensure continuous observation, the attitude of the observer is adjusted synchronously during the rendezvous. Finally, the coordinated control of attitude and orbit for the observer is achieved by optimizing the thrust distribution of the onboard propulsion system. Numerical results demonstrate that the combined optimization of the observability and fuel consumption can generate an optimal control trajectory with high tracking accuracy. The simulation also presents how to choose the optimal relative weight of the two optimization terms, optimal rendezvous time and optimal docking point according to the practical requirements to get the best comprehensive performance of observability and fuel consumption. • Necessary and sufficient condition for observability when maneuvering is determined. • Combined optimization of observability and fuel consumption is proposed. • Coordinated control of attitude and orbit ensures the continuity of observation. • Numerical results validate the efficacy of the proposed method. [ABSTRACT FROM AUTHOR]

Equine infectious anemia (EIA) is a contagious disease of horses caused by the equine infectious anemia virus (EIAV). The clinical signs at the acute phase include intermittent high fever, thrombocytopenia, hemorrhage, edema, and anemia. The clinical signs at chronic and relapsing subclinical levels include emaciation and progressive weakness. Surviving horses become lifelong carriers because of the integration of the viral genome into that of the host, and these horses can produce and transmit the virus to other animals. This increases the difficulty of imposing practical control measures to prevent epidemics of this disease. Serological tests measuring the antibodies in equine sera are considered to be a reliable tool for the long-term monitoring of EIA. However, the standard serological tests for EIV either have low sensitivity (e.g., agar gel immunodiffusion test, AGID) or are time consuming to perform (e.g., ELISA and western blotting). The development of a rapid and simple method for detecting the disease is therefore critical to control the spread of EIA. In this study, we designed and developed a colloidal gold immunochromatographic (GICG) test strip to detect antibodies against EIAV based on the double-antigen sandwich. Both the p26 and gp45 proteins were used as the capture antigens, which may help to improve the positive detection rate of the strip. We found that the sensitivity of the test strip was 8 to 16 times higher than those of two commercially available ELISA tests and 128 to 256 times higher than AGID, but 8 to 16 times lower than that of western blotting. The strip has good specificity and stability. When serum samples from experimental horses immunized with the attenuated EIAV vaccine (n = 31) were tested, the results of the test strip showed 100% coincidence with those from NECVB-cELISA and 70.97% with AGID. When testing clinical serum samples (n = 1014), the test strip surprisingly provided greater sensitivity and a higher number of "true positive" results than other techniques. Therefore, we believe that the GICG test strip has demonstrated great potential in the field trials as a simple and effective tool for the detection of antibodies against EIAV. Key points: • A colloidal gold immunochromatographic (GICG) fast test strip was developed with good specificity, sensitivity, stability, and repeatability • The test strip can be used in point-of-care testing for the primary screening of EIAV antibodies • Both the p26 and gp45 proteins were used as the capture antigens, giving a high positive detection rate in the testing of experimentally infected animal and field samples [ABSTRACT FROM AUTHOR]

Equine infectious anemia (EIA) is a contagious disease of horses caused by the equine infectious anemia virus (EIAV). The clinical signs at the acute phase include intermittent high fever, thrombocytopenia, hemorrhage, edema, and anemia. The clinical signs at chronic and relapsing subclinical levels include emaciation and progressive weakness. Surviving horses become lifelong carriers because of the integration of the viral genome into that of the host, and these horses can produce and transmit the virus to other animals. This increases the difficulty of imposing practical control measures to prevent epidemics of this disease. Serological tests measuring the antibodies in equine sera are considered to be a reliable tool for the long-term monitoring of EIA. However, the standard serological tests for EIV either have low sensitivity (e.g., agar gel immunodiffusion test, AGID) or are time consuming to perform (e.g., ELISA and western blotting). The development of a rapid and simple method for detecting the disease is therefore critical to control the spread of EIA. In this study, we designed and developed a colloidal gold immunochromatographic (GICG) test strip to detect antibodies against EIAV based on the double-antigen sandwich. Both the p26 and gp45 proteins were used as the capture antigens, which may help to improve the positive detection rate of the strip. We found that the sensitivity of the test strip was 8 to 16 times higher than those of two commercially available ELISA tests and 128 to 256 times higher than AGID, but 8 to 16 times lower than that of western blotting. The strip has good specificity and stability. When serum samples from experimental horses immunized with the attenuated EIAV vaccine (n = 31) were tested, the results of the test strip showed 100% coincidence with those from NECVB-cELISA and 70.97% with AGID. When testing clinical serum samples (n = 1014), the test strip surprisingly provided greater sensitivity and a higher number of “true positive” results than other techniques. Therefore, we believe that the GICG test strip has demonstrated great potential in the field trials as a simple and effective tool for the detection of antibodies against EIAV. Key points: • A colloidal gold immunochromatographic (GICG) fast test strip was developed with good specificity, sensitivity, stability, and repeatability • The test strip can be used in point-of-care testing for the primary screening of EIAV antibodies • Both the p26 and gp45 proteins were used as the capture antigens, giving a high positive detection rate in the testing of experimentally infected animal and field samples [ABSTRACT FROM AUTHOR]

This paper presents a trajectory-optimization method for a chaser spacecraft operating in ultra-close proximity to a failed satellite. Based on the combination of active and passive trajectory protection, the constraints in the optimization framework are formulated for collision avoidance and successful docking in the presence of any thruster failure. The constraints are then handled by an adaptive Gauss pseudospectral method, in which the dynamic residuals are used as the metric to determine the distribution of collocation points. A finite-time feedback control is further employed in tracking the optimized trajectory. In particular, the stability and convergence of the controller are proved. Numerical results are given to demonstrate the effectiveness of the proposed methods. [ABSTRACT FROM AUTHOR]

In this paper, a path planning algorithm for a multi-arm space robot is proposed. The robot is capable of maneuvering on the exterior of a large space station. Based on the maneuver strategy, continuous and smooth trajectories of the manipulator end effectors are first determined via the polynomial interpolation method. Then, the kinematics describing the relation between the end effector and the joint angles as well as the platform are formulated. A Moore–Penrose pseudoinverse solution of the joint trajectories is calculated to describe the motion of the manipulators, particularly, considering the singularity avoidance. In addition, a collision detection algorithm is developed to estimate the security during operation. Constraints are formulated by considering collision avoidance, based on which a collision-free trajectory is optimized through the multiplier-penalty method. The numerical results of a triple-arm space robotic system are given to demonstrate the effectiveness of the proposed algorithms. [ABSTRACT FROM AUTHOR]

This paper presents a trajectory planning algorithm to optimise the collision avoidance of a chasing spacecraft operating in an ultra-close proximity to a failed satellite. The complex configuration and the tumbling motion of the failed satellite are considered. The two-spacecraft rendezvous dynamics are formulated based on the target body frame, and the collision avoidance constraints are detailed, particularly concerning the uncertainties. An optimisation solution of the approaching problem is generated using the Gauss pseudospectral method. A closed-loop control is used to track the optimised trajectory. Numerical results are provided to demonstrate the effectiveness of the proposed algorithms. [ABSTRACT FROM AUTHOR]

Pullulanase (EC 3.2.1.41) plays an important role in the specific hydrolysis of branch points in amylopectin. Enhancing its thermostability is required for its industrial application. In this study, rational protein design was used to improve the thermostability of PulB from Bacillus naganoensis (AB231790.1), which has strong enzymatic properties. Three positive single-site mutants (PulB-D328H, PulB-N387D, and PulB-A414P) were selected from six mutants. After incubation at 65°C for 5 min, the residual activities of PulB-D328H, PulB-N387D, and PulB-A414P were 4.5-, 1.7-, and 1.47-fold higher than PulB-WT, and their Tm values (the temperature at which half protein molecule denature) were 1.8°C, 0.4°C, and 0.9°C higher than PulB-WT, respectively. Then the final combined mutant PulB-328/387/414 was constructed. The t1/2 of it was 12.9-fold longer than that of PulB-WT at 65°C and the total increase in Tm of it (5.0°C) was almost 60% greater than the sum of individual increases (3.1°C). In addition, kinetic studies revealed that the kcat and the kcat/Km of PulB-328/387/414 increased by 38.8% and 12.9%. The remarkable improvement in thermostability and the high catalytic efficiency of PulB-328/387/414 make it suitable for industrial applications. [ABSTRACT FROM AUTHOR]

In Hepatitis B virus (HBV) infection, the virus generates numerous viral mRNAs/proteins and viral loads, which plays a major role in driving T cell tolerance, viral persistence, and hepatocellular carcinoma. However, currently available anti-HBV agents have no direct effect on viral mRNA transcription and protein expression. In this study, we designed a recombinant fusion of p53 protein with the cell-penetrating peptide PTD (protein transduction domain of trans-activator of transcription), which mediated p53 internalization into hepatocytes. PTD-p53 effectively suppressed HBV transcription and antigen expression by interaction with viral enhancers. We further provide evidence that PTD-p53 counteracts the viral transcription feedback loop and effectively suppressed HBV production of viral mRNAs, as well as HBsAg, HBeAg, and HBcAg, both in vitro and in vivo. Our results thereby provide a basis for developing a new therapeutic approach against HBV infection. [ABSTRACT FROM AUTHOR]

The resistance to apoptosis displayed by liver cancer plays a key role in hepatocarcinogenesis, tumor progression, and resistance to chemo- or radio-therapy. In this study, we uncovered the potential role and mechanism of heat shock protein gp96 in regulating liver tumor cell growth and apoptosis. P53 protein was identified as a gp96 client protein by profiling apoptosis-related proteins in gp96-knockdown liver cancer cells. Overexpression and knockdown studies both demonstrated that gp96 decreases p53 protein levels, and gp96 regulated cell apoptosis in a p53-dependent manner. We further provide evidence that gp96 interacts with both p53 and Mdm2 to enhance Mdm2-mediated p53 ubiquitination and degradation. Moreover, targeting gp96 with siRNA induced cell apoptosis and led to the suppression of liver tumor growth in vivo . In conclusion, we elucidated an underlying mechanism by which gp96 promotes p53 degradation via increasing Mdm2 E3 ligase activity and provided a new therapeutic strategy to target the gp96-mediated anti-apoptotic characteristic of hepatocellular carcinoma. [ABSTRACT FROM AUTHOR]

Three-dimensional bi-functional modular graphene network (3D bmG) is developed by using metal powder assisted soluble salt templates method. The 3D bmG contains two kinds of modules with different functions: the 3D graphene catalyzed by Ni powder (3D bmG-n) and the 3D graphene grown on NaCl crystals (3D bmG-s). The 3D bmG-n with high crystallization degree ensures the high electrical conductivity and structural stability and protects the 3D bmG-s from etching in electrolyte. The 3D bmG-s with more defects and pores provides high capacity and rate properties. Thus, the synergistic effects of the two modules endow the 3D bmG excellent electrochemical performance as both cathode and anode of lithium-ion capacitors (LICs). The as-prepared "all-carbon" bmG//bmG full LIC with a high voltage window of 4.5 V presents high energy densities of 278 Wh kg−1 and 52.2 Wh kg−1 at power densities of 405 W kg−1 and 16200 W kg−1, respectively, and excellent cycling stability with a capacity retention ratio of 88.57% after 3000 cycles, which is superior compared with LICs reported previously. These properties indicate promising application of 3D bmG in high performance energy storage devices, and the modular design in this work will inspire more designs and types of 3D materials. [Display omitted] • 3D bi-functional modular graphene network was successfully developed. • Two modules with specific structures ensure synergistic improvement of properties. • 4.5 V symmetrical LIC achieved high energy and power density and long cycle life. [ABSTRACT FROM AUTHOR]

• Nanosized Ag-modified 2D/2D hydroxylated g-C 3 N 4 /TS-1 Z-scheme nanocomposites were synthesized for photocatalytic CO 2 RR. • The Z-scheme charge transfer and separation mechanism between g-C 3 N 4 and TS-1 has been clearly verified. • Ag NPs function as electron capturers benefiting the charge separation meanwhile as catalytic sites for activating CO 2. • This work showcases an effective and feasible design strategy to fabricate highly effective TS–1 based photocatalysts. It is significant to enhance the charge separation and extend the visible-light range for the TS-1 molecular sieve-based photocatalysts to improve the photocatalytic performance for CO 2 reduction reaction (CO 2 RR). Here, dimension-matched 2D/2D hydroxylated g-C 3 N 4 /TS-1 (hCN/TS-1) nanocomposites have been successfully fabricated and further modified by nanosized Ag by the photoreduction method. The optimum Ag-modified hCN/TS-1 exhibits ∼ 7-time CO 2 conversion than that of 2D TS-1. Based on the surface photovoltage responses, monochromatic photocurrent action spectra and electrochemical reduction curves, it is confirmed that the exceptional photoactivity is attributed to the greatly-enhanced charge separation via the Z-scheme mode between hCN and TS-1 at intimately-connected interfaces, extended visible-light absorption endowed by hCN, and Ag nanoparticles as the effective electron capturers with favorable catalytic function for activating CO 2 molecules. This work showcases an effective and feasible design strategy to fabricate highly effective TS-1 molecular sieve-based photocatalysts for practical application. [ABSTRACT FROM AUTHOR]

Equine abortus salmonellosis is a bacterial disease that causes high abortion rates in susceptible equids and therefore significant economic losses. Although the tube agglutination test (TAT) is a commonly used serological test for S. Abortusequi, it is not highly specific or sensitive, and the development of more sensitive, specific and rapid assays is therefore urgently required. In this study, an indirect enzyme-linked immunosorbent assay (iELISA) was developed for the specific detection of flagellum protein (FljB) antibodies against S. Abortusequi. Negative sera from horses in China (n = 1030) were used to establish the baseline for a negative population, and reference antisera positive against other viruses or bacteria were used to test the cross reactivity of the technique. The performance of the FljB iELISA was evaluated against that of the standard TAT, and was tested using field serum samples. The FljB iELISA assay was 8–16 times more sensitive than TAT. ROC analysis showed that the FljB iELISA was accurate, with an area under the curve (AUC) = 0.9943 (95% CI, 0.9815–1.000). The diagnostic sensitivity (DSe) of the FljB iELISA was 98.9% (95% Cl, 93.84%–100.00%), which was higher than that of TAT (DSe 38.6; 95% CI, 29.14%–49.08%). The diagnostic specificity (DSp) of the iELISA was 100.0% (95% CI, 95.82%–100.0%). When the 508 clinical samples were tested, the FljB iELISA had a positive detection rate of 51.38% (261/508, 95% CI, 51.24%–51.51%), which was higher than that of TAT (44/508). We also performed a serological survey for S. Abortusequi infection, using a series of samples collected from across eighteen provinces of China in 2021. The results showed that all provinces except Jiangsu had a certain number of cases, and the positive rates ranged from 0% to 96.9%, indicating the wide spread of S. Abortusequi in China. The abovementioned results suggest that the FljB iELISA developed in this study is rapid, sensitive, specific, and repeatable and is likely to be a suitable test for large-scale serological surveys for the detection and control of S. Abortusequi infection. [ABSTRACT FROM AUTHOR]

Equine infectious anemia (EIA) is an important viral disease characterized by persistent infection in equids worldwide. Most EIA cases are life-long virus carriers with low antibody reactions and without the appearance of clinical symptoms. A serological test with high sensitivity and specificity is required to detect inapparent infection. In this study, a B-cell common epitope-based blocking ELISA (bELISA) was developed using a monoclonal antibody together with the EIAV p26 protein labelled with HRP. The test has been evaluated against the standard and with field serum samples globally. This bELISA test can be completed within 75 min, and the sensitivity is higher than those of either the AGID or one commercial cELISA kit. This bELISA assay was 8–16 times more analytically sensitive than AGID, and 2 to 4 times more analytically sensitive than one cELISA kit by testing three sera from the USA, Argentina, and China, respectively. The 353 serum samples from Argentina were tested, in comparison with AGID, the diagnostic sensitivity and specificity of our bELISA assay were 100% (154/154) and 97.0% (193/199), respectively, and the accuracy of the bELISA test was 98.3%. The bELISA test developed in this study is a rapid, sensitive, specific method for the detection of EIAV infection, and could be a promising candidate for use in the monitoring of the EIA epidemic worldwide. Key points: • A universal epitope-based blocking enzyme-linked immunosorbent assay (bELISA) was developed for detection of antibodies to EIAV. • The bELISA assay can be used to test EIAV serum samples from different regions of the world including North America, South America, Europe, and Asia. • The bELISA assay was evaluated in three different international labs and showed a better performance than other commercial kits. [ABSTRACT FROM AUTHOR]

Due to the continuous evolution of SARS-CoV-2, the Omicron variant has emerged and exhibits severe immune evasion. The high number of mutations at key antigenic sites on the spike protein has made a large number of existing antibodies and vaccines ineffective against this variant. Therefore, it is urgent to develop efficient broad-spectrum neutralizing therapeutic drugs. Here we characterize a rabbit monoclonal antibody (RmAb) 1H1 with broad-spectrum neutralizing potency against Omicron sublineages including BA.1, BA.1.1, BA.2, BA.2.12.1, BA.2.75, BA.3 and BA.4/5. Cryo-electron microscopy (cryo-EM) structure determination of the BA.1 spike-1H1 Fab complexes shows that 1H1 targets a highly conserved region of RBD and avoids most of the circulating Omicron mutations, explaining its broad-spectrum neutralization potency. Our findings indicate 1H1 as a promising RmAb model for designing broad-spectrum neutralizing antibodies and shed light on the development of therapeutic agents as well as effective vaccines against newly emerging variants in the future. The molecular mechanism of broad-spectrum neutralization of a rabbit monoclonal antibody 1H1 against Omicron sublineages is revealed by cryo-EM. [ABSTRACT FROM AUTHOR]

The equine infectious anemia virus (EIAV) capsid protein (p26) is one of the major immunogenic proteins during EIAV infection and is widely used for the detection of EIAV antibodies in horses. However, few reports have described the use of EIAV-specific monoclonal antibodies (MAbs) in etiological and immunological detection. Previously, we developed an antigen capture enzyme-linked immunosorbent assay (AC-ELISA) for the quantification of the EIAV p26 protein level. However, the epitopes recognized by the MAbs were not identified, and the utilization of the MAbs needs to be evaluated. In this study, we characterized two monoclonal antibodies (9H8 and 1G11 MAbs) against EIAV p26. Two B-cell epitopes are located in amino acid residues, NLDKIAEE (HE) and KNAMRHLRPEDTLEEKMYAC (GE) for the 9H8 and 1G11 MAbs, respectively. The 1G11 epitope (GE) varied among viruses isolated worldwide but can be recognized by anti-EIAV sera from different regions, including China, the USA, and Argentina. Meanwhile, 1G11 MAb could react with the mutants of almost all the EIAV strains. Furthermore, we found that the histidine at position 204 (H204), leucine at position 205 (L205), and aspartic acid at position 209 (D209) of EIAV p26 individually played pivotal roles in binding with the 1G11 MAb. Our results revealed that the GE peptide might be a common B-cell binding epitope of EIAV antibodies. This is also the first report to identify a broad-spectrum monoclonal antibody (1G11) against p26 of EIAV. These findings may provide a useful basis for the development of new diagnostic assays for EIAV. [ABSTRACT FROM AUTHOR]

P4 is a functional small peptide screened after enzymatic hydrolysis of cotton meal. Bacillus subtilis CM66 (OB) underwent recombination to yield Bacillus subtilis CM66-P4' (RB), capable of secreting P4. This study aimed to assess the effects of RB on the growth, antioxidant capacity and intestine in blunt snout bream (Megalobrama amblycephala) through in vitro and in vivo experiments. Seven groups were formed: a control group (CG) with no additional bacteria, three groups with different concentrations of Bacillus subtilis CM66 (2 × 107, 2 × 108, 2 × 109 CFU/kg - referred to as LOG, MOG, HOG), and three groups with corresponding concentrations of Bacillus subtilis CM66-P4' (2× 107, 2 × 108, 2 × 109 CFU/kg - referred to as LRG, MRG, HRG). After 8 weeks of feeding, the results showed that OB and RB had no significant impact on growth performance. Compared with CG and MOG, the MRG group exhibited a significant increase in protease and total anti-oxidative capacity (T-AOC) in the intestine (P < 0.05). The mRNA expression of mucin-2 in MOG and MRG were significantly increased (P < 0.05). Compared with CG, muscle layer thickness (MLT) of MOG and MRG were significantly increased (P < 0.05), villus height (VH) and goblet cells numbers of MRG were increased (P < 0.05). Species richness and diversity of intestinal microbes were significantly increased in MOG and MRG (P < 0.05). P4 demonstrated a significant alleviation of the increase in sod expression in intestinal epithelial cells (IECs) treated with H 2 O 2 and mitigated the decrease in cells activity (P < 0.05). In conclusion, P4 effectively mitigated the impact of H 2 O 2 on IECs in blunt snout bream. Dietary supplementation of 2 × 108 CFU/kg RB (secreting P4) improved the intestinal microbes and intestinal barrier, resulting in enhanced antioxidant capacity. • Recombinant Bacillus subtilis can effectively carry the cotton meal P4' peptide; • Both recombinant and unmodified B. subtilis improved the antioxidant capacity and intestine in Megalobrama amblycephala ; • Recombinant B. subtilis exerted better effects than the unmodified one; [ABSTRACT FROM AUTHOR]

Soil thermal conductivity is critical for determining the hydrological and energy transfer processes in permafrost regions and simulating hydrological and thermal dynamic processes with land surface models. In this study, improved thermal conductivity parameterizations of the Simultaneous Heat and Water model (SHAW) were assessed using observation data from permafrost regions on the Qinghai-Tibet Plateau (QTP). The results indicated that the SHAW could precisely describe soil hydrological and thermal processes at the Tanggula (TGL) site. In general, the performances of Johansen's, Luo's, and the ORCHIDEE-MICT model's soil organic matter (SOM) parameterizations were superior to the original De Vries's parameterization. The SOM parameterization performed the best. The root mean square error (RMSE) of the active layer's soil temperature was 0.42 °C lower than that of the original parameterization at the Xidatan (XDT) site and 0.2 °C lower at the TGL site. In particular, the RMSE of the soil temperature at 3 m depth at TGL was 0.8 °C lower than that of the original parameterization. The average Nash-Sutcliffe Efficiency (NSE) for simulating the active layer soil temperature using the SOM parameterization was 0.915 at TGL site and 0.806 at XDT site. While De Vries parameterization yielded average NSE values of 0.771 and 0.627 for soil temperature simulations at the two sites, respectively. The results indicate that the soil organic carbon cannot be ignored in the simulation of hydrological and thermal processes in permafrost areas with a high soil organic carbon content. Notably, the simulated soil temperatures during the freezing period and the soil liquid water content during the thawing period improved significantly after modifying the thermal conductivity parameterization of SHAW. Therefore, the revised SHAW more accurately reflects the water and heat transfer processes of permafrost and can be used to analyze land-atmosphere interactions. • Adopting the SHAW model to assess the applicability of four soil thermal conductivity parameterizations in permafrost regions of the QTP. • Soil thermal parameterization considering soil organic matter (SOM parameterization) is more applicable to the permafrost regions and the SHAW model. • Utilizing the improved SHAW model enables accurate simulation of the hydrological and thermal changes in permafrost regions. [ABSTRACT FROM AUTHOR]

In the natural host, most of the synonymous codons of a gene have been evolutionarily selected and related to protein expression and function. However, for the design of a new gene, most of the existing codon optimization tools select the high-frequency-usage codons and neglect the contribution of the low-frequency-usage codons (rare codons) to the expression of the target gene in the host. In this study, we developed the method Presyncodon, available in a web version, to predict the gene code from a protein sequence, using built-in evolutionary information on a specific expression host. The synonymous codon-usage pattern of a peptide was studied from three genomic datasets (Escherichia coli, Bacillus subtilis, and Saccharomyces cerevisiae). Machine-learning models were constructed to predict a selection of synonymous codons (low- or high-frequency-usage codon) in a gene. This method could be easily and efficiently used to design new genes from protein sequences for optimal expression in three expression hosts (E. coli, B. subtilis, and S. cerevisiae). Presyncodon is free to academic and noncommercial users; accessible at http://www.mobioinfor.cn/presyncodon_www/index.html. [ABSTRACT FROM AUTHOR]

In the previous study, the results on two interesting egfp genes indicated that the expressed eGFP production of egfp-codon containing multiple rare codons was 2.3-fold than that of egfp-genscript with mainly high-frequency-usage codons. Therefore, the rare codons also play important roles for the functional expression of genes and it is interesting to know which rare codons in the egfp affect the functional expression of eGFP. In this study, the structure-guided SCHEMA recombination method and site-specific mutagenesis were proposed to detect the contribution of the rare codons on the functional expression of eGFP. The 12 chimeric egfps were generated from egfp-codon and egfp-genscript by the software SCHEMA. The results indicated that it was the rare codons in the C-terminal coding region (residues from 147 to 239) of eGFP resulting in the higher expression levels in Escherichia coli . The single and multiple point mutations also indicated that the presence of rare codons in 3′ coding regions of egfp could enhance the functional expression of eGFP in E. coli . Therefore, the gene sequence on the C-terminal could also affect its functional expression and the strategy of substituting rare codons into coding sequences might be an effective method for increasing heterologous proteins in the host. [ABSTRACT FROM AUTHOR]

Pichia pastoris is commonly used to express and secrete target proteins, although not all recombinant proteins can be successfully produced. In this study, we used methyl parathion hydrolase (MPH) from Ochrobactrum sp. M231 as a model to study the importance of the N-terminus of the protein for its secretion. While MPH can be efficiently expressed intracellularly in P. pastoris, it is not secreted into the extracellular environment. Three MPH mutants (N66-MPH, D10-MPH, and N9-MPH) were constructed through modification of its N-terminus, and the secretion of each by P. pastoris was improved when compared to wild-type MPH. The level of secreted D10-MPH was increased to 0.21 U/mL, while that of N9-MPH was enhanced to 0.16 U/mL. Although N66-MPH was not enzymatically active, it was secreted efficiently, and was identified by SDS-PAGE. These results demonstrate that the secretion of heterologous proteins in P. pastoris may be improved by modifying their N-terminal structures. [ABSTRACT FROM AUTHOR]

Good protein thermostability is very important for the protein application. In this report, we propose a strategy which contained a prediction method to select residues related to protein thermal stability, but not related to protein function, and an experiment method to screen the mutants with enhanced thermostability. The prediction strategy was based on the calculated site evolutionary entropy and unfolding free energy difference between the mutant and wild-type (WT) methyl parathion hydrolase enzyme from Ochrobactrum sp. M231 [ Ochr-methyl parathion hydrolase (MPH)]. As a result, seven amino acid sites within Ochr-MPH were selected and used to construct seven saturation mutagenesis libraries. The results of screening these libraries indicated that six sites could result in mutated enzymes exhibiting better thermal stability than the WT enzyme. A stepwise evolutionary approach was designed to combine these selected mutants and a mutant with four point mutations (S274Q/T183E/K197L/S192M) was selected. The T and T of the mutant enzyme were 11.7 and 10.2 °C higher, respectively, than that of the WT enzyme. The success of this design methodology for Ochr-MPH suggests that it was an efficient strategy for enhancing protein thermostability and suitable for protein engineering. [ABSTRACT FROM AUTHOR]

Protein thermostability can be increased by some glycine to proline mutations in a target protein. However, not all glycine to proline mutations can improve protein thermostability, and this method is suitable only at carefully selected mutation sites that can accommodate structural stabilization. In this study, homology modeling and molecular dynamics simulations were used to select appropriate glycine to proline mutations to improve protein thermostability, and the effect of the selected mutations was proved by the experiments. The structure of methyl parathion hydrolase (MPH) from Ochrobactrum sp. M231 ( Ochr-MPH) was constructed by homology modeling, and molecular dynamics simulations were performed on the modeled structure. A profile of the root mean square fluctuations of Ochr-MPH was calculated at the nanosecond timescale, and an eight-amino acid loop region (residues 186-193) was identified as having high conformational fluctuation. The two glycines nearest to this region were selected as mutation targets that might affect protein flexibility in the vicinity. The structures and conformational fluctuations of two single mutants (G194P and G198P) and one double mutant (G194P/G198P) were modeled and analyzed using molecular dynamics simulations. The results predicted that the mutant G194P had the decreased conformational fluctuation in the loop region and might increase the thermostability of Ochr-MPH. The thermostability and kinetic behavior of the wild-type and three mutant enzymes were measured. The results were consistent with the computational predictions, and the mutant G194P was found to have higher thermostability than the wild-type enzyme. [ABSTRACT FROM AUTHOR]

Abstract: Organophosphorus (OP) compounds are widely used as pesticides in agriculture but cause broad-area environmental pollution. In this work, we have expressed a bacterial organophosphorus hydrolase (OPH) gene in tobacco plants. An assay of enzyme activity showed that transgenic plants could secrete OPH into the growth medium. The transgenic plants were resistant to methyl parathion (Mep), an OP pesticide, as evidenced by a toxicity test showing that the transgenic plants produced greater shoot and root biomass than did the wild-type plants. Furthermore, at 0.02% (v/v) Mep, the transgenic plants degraded more than 99% of Mep after 14 days of growth. Our work indicates that transgenic plants expressing an OPH gene may provide a new strategy for decontaminating OP pollutants. [Copyright &y& Elsevier]

The amino acid sequences of N-terminal and internal peptide of OPHC2, purified from Pseudomonas pseudoalcaligenes strain C2-1 in our lab, are determined. The full-length organphosphorus hydrolase gene ophc2 is cloned by PCR using the degenerate primers designed according to the sequences and future inverse PCR. The ophc2 gene is 975 bp long with G+C content of 63 %, comprising one open reading frame encoding a polypeptide of 324 amino acids with a molecular weight of 36 kD. The nucleotide sequence of ophc2 shows low homologies with those organphosphorus hydrolase genes deposited in GenBank, one of which exhibits the highest homology of 46.4% with ophc2. The organphosphorus hydrolase protein expressed in E1 coil bears normal bioactivitv. [ABSTRACT FROM AUTHOR]

• An EG PCR for AMDV was developed for the first time. • The EG PCR was able to detect both American and Chinese strains of AMDV. • The detection rate of the EG PCR was higher than that of CIEP. The objective of this study was to develop a rapid, sensitive and specific EvaGreen (EG)-based real-time PCR assay capable of detecting Aleutian mink disease virus (AMDV) and to evaluate the reliability of the assay for analysis of blood or tissue samples. For this assay, a pair of primers was designed based on a nonstructural protein (NS)-encoding gene of AMDV, and the identity of PCR products was identified based on a melting temperature of 82.8°C. The EG-based real-time PCR assay did not detect canine distemper virus or mink enteritis virus, and the assay could be used to detect Chinese and American AMDV strains, in contrast to a commercial TaqMan kit that could only detect American AMDV strains. The amplification efficiencies of the EG assay were 104.8% for the Chinese strain and 94.4% for the American strain, and the detection limit was 1 copy/μL of AMDV plasmid or 3 pg/μL of viral DNA (Chinese strain). The intra- and inter-assay variation coefficients of melting temperature were all lower than 0.15%, confirming the high reproducibility of the assay. Forty-five clinical blood samples were simultaneously analyzed using the EG real-time PCR, TaqMan kit and conventional PCR, and the detection rates were 91.1%, 0.0% and 86.7%, respectively. Serum samples were also collected from the corresponding blood samples and tested using the counterimmunoelectrophoresis (CIEP) assay, where positive samples accounted for 24.4% of the 45 samples. In conclusion, EG-based real-time PCR is a rapid, sensitive, universal assay that can be effectively utilized as a reliable and specific tool for detection and quantitation of AMDV. [ABSTRACT FROM AUTHOR]

Interferon-mediated host factors myxovirus (Mx) proteins are key features in regulating influenza A virus (IAV) infections. Viral polymerases are essential for viral replication. The Mx1 protein has been known to interact with viral nucleoprotein (NP) and PB2, resulting in the influence of polymerase activity and providing interspecies restriction. The equine influenza virus has evolved as an independent lineage to influenza viruses from other species. We estimated the differences in antiviral activities between human MxA (huMxA) and equine Mx1 (eqMx1) against a broad range of IAV strains. We found that huMxA has antiviral potential against IAV strains from non-human species, whereas eqMx1 could only inhibit the polymerase activity of non-equine species. Here, we demonstrated that NP is the main target of eqMx1. Subsequently, we found adaptive mutations in the NP of strains A/equine/Jilin/1/1989 (H3N8JL89) and A/chicken/Zhejiang/DTID-ZJU01/2013 (H7N9ZJ13) that confer eqMx1 resistance and sensitivity respectively. A substantial reduction in Mx1 resistance was observed for the two mutations G34S and H52N in H3N8JL89 NP. Thus, eqMx1 is an important dynamic force in IAV nucleoprotein evolution. We, therefore, suggest that the amino acids responsible for Mx1 resistance should be regarded as a robust indicator for the pandemic potential of lately evolving IAVs. [ABSTRACT FROM AUTHOR]

Hepatitis B virus (HBV) chronically infects approximately 350 million people worldwide. The replication of HBV which genome is only 3.2 kb long relies heavily on host factors. Previous studies demonstrated that a highly expressed liver-specific microRNA (miRNA) miR-122 suppresses HBV expression and replication in multiple ways. In this study, we found that the miR-122 response elements in viral genome facilitate HBV expression and replication in miR-122 highly-expressed hepatocytes. Moreover, mutations in miR-122 response elements are correlated with viral loads and disease progression in HBV-infected patients. We next found that HBV mRNA with miR-122 response elements alone could lead to altered expression of multiple host genes by whole genome expression analysis. HBV mRNA-mediated miR-122 down-regulation plays a major role in HBV mRNA-induced differential gene expression. HBV mRNA could enhance viral replication via miR-122 degradation and the up-regulation of its target cyclin G1. Our study thereby reveals that under the unique condition of high abundance of miR-122 and viral mRNAs and much lower level of miR-122 target in HBV infection, HBV may have evolved to employ the miRNA-mediated virus and host mRNAs network for optimal fitness within hepatocytes. [ABSTRACT FROM AUTHOR]