Gas Sensors Based on Semiconductor Metal Oxides Fabricated by Electrospinning: A Review.

Electrospinning has revolutionized the field of semiconductor metal oxide (SMO) gas sensors, which are pivotal for gas detection. SMOs are known for their high sensitivity, rapid responsiveness, and exceptional selectivity towards various types of gases. When synthesized via electrospinning, they gain unmatched advantages. These include high porosity, large specific surface areas, adjustable morphologies and compositions, and diverse structural designs, improving gas-sensing performance. This review explores the application of variously structured and composed SMOs prepared by electrospinning in gas sensors. It highlights strategies to augment gas-sensing performance, such as noble metal modification and doping with transition metals, rare earth elements, and metal cations, all contributing to heightened sensitivity and selectivity. We also look at the fabrication of composite SMOs with polymers or carbon nanofibers, which addresses the challenge of high operating temperatures. Furthermore, this review discusses the advantages of hierarchical and core-shell structures. The use of spinel and perovskite structures is also explored for their unique chemical compositions and crystal structure. These structures are useful for high sensitivity and selectivity towards specific gases. These methodologies emphasize the critical role of innovative material integration and structural design in achieving high-performance gas sensors, pointing toward future research directions in this rapidly evolving field.

Comprehensive Review of RF MEMS Switches in Satellite Communications.

The miniaturization and low power consumption characteristics of RF MEMS (Radio Frequency Microelectromechanical System) switches provide new possibilities for the development of microsatellites and nanosatellites, which will play an increasingly important role in future space missions. This paper provides a comprehensive review of RF MEMS switches in satellite communication, detailing their working mechanisms, performance optimization strategies, and applications in reconfigurable antennas. It explores various driving mechanisms (electrostatic, piezoelectric, electromagnetic, thermoelectric) and contact mechanisms (capacitive, ohmic), highlighting their advantages, challenges, and advancements. The paper emphasizes strategies to enhance switch reliability and RF performance, including minimizing the impact of shocks, reducing driving voltage, improving contacts, and appropriate packaging. Finally, it discusses the enormous potential of RF MEMS switches in future satellite communications, addressing their technical advantages, challenges, and the necessity for further research to optimize design and manufacturing for broader applications and increased efficiency in space missions. The research findings of this review can serve as a reference for further design and improvement of RF MEMS switches, which are expected to play a more important role in future aerospace communication systems.

Curcumin improves the egg quality, antioxidant activity, and intestinal microbiota of quails during the late laying period.

This study aimed to investigate the effects of dietary curcumin supplementation on laying performance, egg quality, egg metabolites, lipid metabolism, antioxidant activity, and intestinal microbial composition of quails in the late laying period. A total of 960 late-laying quails (240-day-old) were randomly divided into 4 groups of 6 replicates each (n = 40/replicate). The experimental diets of the 4 groups consisted of basal diets supplemented with 0, 50, 100, and 200 mg/kg curcumin, respectively. The feeding experiment lasted for 8 wk. The results showed that 200 mg/kg curcumin supplementation decreased mortality and increased eggshell thickness and strength compared with the 0 mg/kg curcumin supplementation during wk 5 to 8. In addition, dietary supplementation of curcumin promoted lipid metabolism, enhanced antioxidant activity, and modified intestinal microbiota structure. In conclusion, dietary supplemented with 200 mg/kg curcumin significantly improved the egg quality of quails in the late laying period, primarily by improving lipid metabolism and selectively regulating the intestinal microbial community.

MR Imaging Radiomics Analysis Based on Lumbar Soft Tissue to Evaluate Lumbar Fascia Changes in Patients with Low Back Pain.

RATIONALE AND OBJECTIVES: Clinicians must precisely pinpoint the etiology of low back pain as the number of people suffering from it increases to provide targeted care. The purpose of this paper was to use MR imaging radiomics based on lumbar soft tissue to analyze changes in the lumbar fascia of patients with low back pain. MATERIALS AND METHODS: We retrospectively analyzed the lumbar MRI of 197 patients with low back pain. Patients were randomly assigned to either the training (n = 138) or validation (n = 59) cohorts. Multivariate logistic regression analysis was used to create radiomics model and combined nomogram model and their predictive performance were evaluated using receiver operating characteristic curves. RESULTS: Seven radiomics features based on lumbar soft tissue MRI images were established, which performed well in distinguishing between low back pain patients with fascial changes and normal individuals demonstrated an excellent ability to identify differences, with an Area Under Curve (AUC) of 0.92 (95% CI, 0.88-0.96) in the training cohort and 0.84 (95% CI, 0.73-0.96) in the validation cohort, which performed better than the clinical model significantly only. CONCLUSION: The nomogram based on clinical features and radiomics features of MR images had a good predictive ability to differentiate fascial alterations in patients with low back pain from normal subjects. It had the potential to be used as a decision support tool to assist clinicians in determining the etiology of patients with lower back pain and managing patients promptly, particularly in the early stage of the fasciitis when significant abnormalities on imaging were difficult to detect.

UWB Frequency-Selective Surface Absorber Based on Graphene Featuring Wide-Angle Stability.

In this paper, an ultra-wideband and polarization-insensitive frequency-selective surface absorber is presented with oblique incident stable behavior. Different from conventional absorbers, the absorption behavior is much less deteriorated with the increase in the incidence angle. Two hybrid resonators, which are realized by symmetrical graphene patterns, are employed to obtain the desired broadband and polarization-insensitive absorption performance. The optimal impedance-matching behavior is designed at the oblique incidence of electromagnetic waves, and an equivalent circuit model is used to analyze and facilitate the mechanism of the proposed absorber. The results indicate that the absorber can maintain a stable absorption performance with a fractional bandwidth (FWB) of 136.4% up to 40°. With these performances, the proposed UWB absorber could be more competitive in aerospace applications.

Design and Analysis of a Fluid-Filled RF MEMS Switch.

In the present study, a fluid-filled RF MEMS (Radio Frequency Micro-Electro-Mechanical Systems) switch is proposed and designed. In the analysis of the operating principle of the proposed switch, air, water, glycerol and silicone oil were adopted as filling dielectric to simulate and research the influence of the insulating liquid on the drive voltage, impact velocity, response time, and switching capacity of the RF MEMS switch. The results show that by filling the switch with insulating liquid, the driving voltage can be effectively reduced, while the impact velocity of the upper plate to the lower plate is also reduced. The high dielectric constant of the filling medium leads to a lower switching capacitance ratio, which affects the performance of the switch to some extent. By comparing the threshold voltage, impact velocity, capacitance ratio, and insertion loss of the switch filled with different media with the filling media of air, water, glycerol, and silicone oil, silicone oil was finally selected as the liquid filling medium for the switch. The results show that the threshold voltage is 26.55 V after filling with silicone oil, which is 43% lower under the same air-encapsulated switching conditions. When the trigger voltage is 30.02 V, the response time is 10.12 µs and the impact speed is only 0.35 m/s. The frequency 0-20 GHz switch works well, and the insertion loss is 0.84 dB. To a certain extent, it provides a reference value for the fabrication of RF MEMS switches.

A lightweight attention deep learning method for human-vehicle recognition based on wireless sensing technology.

Wireless sensing-based human-vehicle recognition (WiHVR) methods have become a hot spot for research due to its non-invasiveness and cost-effective advantages. However, existing WiHVR methods shows limited performance and slow execution time on human-vehicle classification task. To address this issue, a lightweight wireless sensing attention-based deep learning model (LW-WADL) is proposed, which consists of a CBAM module and several depthwise separable convolution blocks in series. LW-WADL takes raw channel state information (CSI) as input, and extracts the advanced features of CSI by jointly using depthwise separable convolution and convolutional block attention mechanism (CBAM). Experimental results show that the proposed model achieves 96.26% accuracy on the constructed CSI-based dataset, and the model size is only 5.89% of the state of the art (SOTA) model. The results demonstrate that the proposed model achieves better performance on WiHVR tasks while reducing the model size compared to SOTA model.

Effect of RNA interference with glutamate decarboxylase on acid resistance of Trichinella spiralis.

Trichinella spiralis is a zoonotic parasite that infects most mammals, even humans. Glutamate decarboxylase (GAD) is an important enzyme in glutamate-dependent acid resistance system 2 (AR2), but the GAD of T. spiralis in AR2 is unclear. We aimed to investigate the role of T. spiralis glutamate decarboxylase (TsGAD) in AR2. We silenced the TsGAD gene to evaluate the AR of T. spiralis muscle larvae (ML) in vivo and in vitro via siRNA. The results showed that recombinant TsGAD was recognized by anti-rTsGAD polyclonal antibody (57 kDa), and qPCR indicated that TsGAD transcription peaked at pH 2.5 for 1 h compared to that with pH 6.6 phosphate-buffered saline. Indirect immunofluorescence assays revealed that TsGAD was expressed in the epidermis of ML. After TsGAD silencing in vitro, TsGAD transcription and the survival rate of ML decreased by 15.2% and 17%, respectively, compared with those of the PBS group. Both TsGAD enzymatic activity and the acid adjustment of siRNA1-silenced ML were weakened. In vivo, each mouse was orally infected with 300 siRNA1-silenced ML. On days 7 and 42 post-infection, the reduction rates of adult worms and ML were 31.5% and 49.05%, respectively. Additionally, the reproductive capacity index and larvae per gram of ML were 62.51±7.32 and 1250.22±146.48, respectively, lower than those of the PBS group. Haematoxylin-eosin staining revealed many inflammatory cells infiltrating the nurse cells in the diaphragm of mice infected with siRNA1-silenced ML. The survival rate of the F1 generation ML was 27% higher than that of the F0 generation ML, but there was no difference from the PBS group. These results first indicated that GAD plays a crucial role in AR2 of T. spiralis. TsGAD gene silencing reduced the worm burden in mice, providing data for the comprehensive study of the AR system of T. spiralis and a new idea for the prevention of trichinosis.

Multivalent Effect of Defect Engineered Ag2S/g-C3N4 3D Porous Floating Catalyst with Enhanced Contaminant Removal Efficiency.

Chlorophenols, as a major environmental pollutant, enter water systems through industrial wastewater, agricultural runoff and chemical spills, and they are stable, persistent under natural conditions, and highly hazardous to water resources. The objective of this article is to prepare Ag2S-modified C3N4 three-dimensional network photocatalyst by calcination method to use photocatalysis as an efficient, safe, and environmentally friendly method to degrade chlorophenols. Ag2S/C3N4 has an excellent visible light absorption range, low band gap, effective separation of photogenerated charges, and active free radicals production, all of which make for the enhancement of photocatalytic degradation performance of the Ag2S/C3N4 system. Under the light irradiation (λ ≥ 420 nm), the photocatalytic degradation efficiency of 2,4,6-Trichlorophenol reach 95% within 150 min, and the stable photocatalytic degradation activity can still be maintained under different pH water environment and four degradation cycles. When Ag2S is loaded on ACNs, more photogenerated electrons are generated and subsequent reactions produce highly reactive groups such as •O2- and •OH that will originally be able to continuously attack TCP molecules to degrade pollutants. Therefore, this study shows that the photocatalyst provides a novel research approach for realizing the application in the field of pollutant degradation.

Grape seed extract proanthocyanidin antagonizes aristolochic acid I-induced liver injury in rats by activating PI3K-AKT pathway.

Aristolochic acid is internationally recognized as a carcinogen. It has been shown that the main toxic mechanism of aristolochic acid on the liver and kidney is the induction of ROS-induced oxidative stress damage. To investigate whether proanthocyanidins (GSPE), a natural antioxidant product from grape seed extract, could antagonize AA-I-induced liver injury. Thirty-two SD rats were selected and divided into aristolochic acid exposure group (AA-I), normal control group, GSPE group and GSPE intervention group. The protective effects of GSPE on AA-I liver injury were evaluated by examining the body weight, liver index, liver function and liver pathological sections of rats. The results of body weight, liver index, liver function and liver pathological sections of rats showed that GSPE had antagonistic effects on AA-I-induced liver injury. antioxidant enzyme activity in the GSPE intervention group was significantly higher than that in the aristolochic acid group, apoptotic cells were significantly lower than that in the aristolochic acid group, protein and mRNA expression of PI3K-AKT and BCL-2 were significantly higher than that in the aristolochic acid group, BAX, The protein and mRNA expression of BAX, CASPAES-3, CASPAES-9 were significantly lower than those of the aristolochic acid group. GSPE can antagonize aristolochic acid-induced hepatotoxicity, and its mechanism of action is to antagonize aristolochic acid I-induced liver injury by inhibiting PI3K-AKT pathway-mediated hepatocyte apoptosis.

Design and Analysis of the Capacitive RF MEMS Switches with Support Pillars.

Conventional parallel capacitive RF MEMS switches have a large impact during the suction phase. In general, RF MEMS switches have to be switched on and off in a considerably fast manner. Increasing the driving voltage enables fast switching but also increases the impact force, which causes the beam membrane to be prone to failure. In the present study, the addition of two support pillars was proposed for slowing down the fall of the beam membrane based on the conventional RF MEMS parallel switch, so as to reduce the impact velocity. As such, a novel RF MEMS switch was designed. Further, simulation software was used to scan and analyze the positioning and height of the support pillars with respect to electromechanical and electromagnetic performance. The simulation results show that the optimal balance of impact velocity and pull-in time was achieved at a height of 0.8 um, a distance of 10 um from the signal line, and an applied voltage of 50 V. The impact velocity was reduced from 1.8 m/s to 1.1 m/s, decreasing by nearly 40%. The turn off time increased from 3.9 us to 4.2 us, representing an increase of only 0.05%. The insertion loss was less than 0.5 dB at 32 GHz, and the isolation was greater than 50 dB at 40 GHz.

Isolation, identification and pathogenic characteristics of tick-derived parainfluenza virus 5 in northeast China.

The number of parainfluenza virus 5 (PIV5) infection cases has increased worldwide over the past six decades; however, factors underlying this increase remain unclear. PIV5 has been emerging or re-emerging in humans and animal species. To date, no information is yet available regarding PIV5 infection in arthropod ticks. Here, we successfully isolated tick-derived PIV5 from the Ixodes persulcatus species designated as HLJ/Tick/2019 in Heilongjiang, China. Phylogenetic analysis revealed that the tick-derived PIV5 is closely related to subclade 2.2.6, which has become the dominant subtype prevalent in dogs, pigs and wildlife across China. Further experiments to understand the importance of this virus as an infectious vector revealed that a ferret animal model experimentally infected with Tick/HLJ/2019 via the oronasal and ocular inoculation routes developed moderate respiratory distress with pneumonia and neurologic tissue damage from inflammation for the first time. Further surveillance of PIV5 in vectors of viral transmission is necessary to enhance our knowledge of its ecology in reservoirs and facilitate the control of re-emerging diseases.

Genome-Wide Characterization of QYYZ-Like PRRSV During 2018-2021.

In the last decade, the emergence of QYYZ-like porcine reproductive and respiratory syndrome virus (PRRSV) has attracted increasing attention due to the high incidence of PRRSV mutation and recombination. However, the endemic status and genomic characteristics of the QYYZ-like strains are unclear. From 2018 to October 2021, 24 QYYZ-like PRRSV isolates were obtained from 787 PRRSV-positive clinical samples. Only one QYYZ-like positive sample was from a northern province, and the rest were from central and southern provinces. We selected 9 samples for whole-genome sequencing, revealing genome lengths of 15,008-15,316 nt. We retrieved all the available whole-genome sequences of QYYZ-like PRRSVs isolated in China from 2010 to 2021 (n = 28) from GenBank and analyzed them together with the new whole-genome sequences (n = 9). Phylogenetic tree analysis based on the ORF5 gene showed that all QYYZ-like PRRSV strains belonged to sublineage 3.5 but were clustered into three lineages (sublineage 1.8, sublineage 3.5, and sublineage 8.7) based on whole-genome sequences. Genomic sequence alignment showed that QYYZ-like strains, have characteristic amino acids insertions or deletions in the Nsp2 region (same as NADC30, JXA1 and QYYZ) and that thirteen strains also had additional amino acid deletions, mostly between 468 and 518 aa. Moreover, QYYZ-like strains (sublineage 3.5) have seven identical characteristic amino acid mutations in ORF5. Recombination analysis revealed that almost all QYYZ-like complete genome sequences (36/37) were products of recombination and mainly provided structural protein fragments (GP2-N) for the recombinant strains. Overall, QYYZ-like strains were mainly prevalent in central and southern China from 2018 to 2021, and these strains provided recombinant fragments in the PRRSV epidemic in China.

A Snapback-Free and Low Turn-Off Loss 15 kV 4H-SiC IGBT with Multifunctional P-Floating Layer.

In this paper, a 4H-SiC IGBT with a multifunctional P-floating layer (MP-IGBT) is proposed and investigated by Silvaco TCAD simulations. Compared with the conventional 4H-SiC field stop IGBT (FS-IGBT), the MP-IGBT structure features a P-floating layer structure under the N-buffer layer. The P-floating layer increases the distributed path resistance below the buffer layer to eliminate the snapback phenomenon. In addition, the P-floating layer acts as an amplifying stage for the hole currents' injection. The snapback-free structure features a half-cell pitch of 10 µm. For the same forward voltage drop, the turn-off loss of the MP-IGBT structure is reduced by 42%.

The Role of Type II Fatty Acid Synthesis Enzymes FabZ, ODSCI, and ODSCII in the Pathogenesis of Toxoplasma gondii Infection.

Toxoplasma gondii is an obligate intracellular protozoan parasite, which has a worldwide distribution and can infect a large number of warm-blooded animals and humans. T. gondii must colonize and proliferate inside the host cells in order to maintain its own survival by securing essential nutrients for the development of the newly generated tachyzoites. The type II fatty acid biosynthesis pathway (FASII) in the apicoplast is essential for the growth and survival of T. gondii. We investigated whether deletion of genes in the FASII pathway influences the in vitro growth and in vivo virulence of T. gondii. We focused on beta-hydroxyacyl-acyl carrier protein dehydratase (FabZ) and oxidoreductase, short chain dehydrogenase/reductase family proteins ODSCI and ODSCII. We constructed T. gondii strains deficient in FabZ, ODSCI, and ODSCII using CRISPR-Cas9 gene editing technology. The results of immunofluorescence assay, plaque assay, proliferation assay and egress assay showed that in RHΔFabZ strain the apicoplast was partly lost and the growth ability of the parasite in vitro was significantly inhibited, while for RHΔODSCI and RHΔODSCII mutant strains no similar changes were detected. RHΔFabZ exhibited reduced virulence for mice compared with RHΔODSCI and RHΔODSCII, as shown by the improved survival rate. Deletion of FabZ in the PRU strain significantly decreased the brain cyst burden in mice compared with PRUΔODSCI and PRUΔODSCII. Collectively, these findings suggest that FabZ contributes to the growth and virulence of T. gondii, while ODSCI and ODSCII do not contribute to these traits.

Micropathogen community identification in ticks (Acari: Ixodidae) using third-generation sequencing.

Ticks are important vectors that facilitate the transmission of a broad range of micropathogens to vertebrates, including humans. Because of their role in disease transmission, it has become increasingly important to identify and characterize the micropathogen profiles of tick populations. The objective of the present study was to survey the micropathogens of ticks by third-generation metagenomic sequencing using the PacBio Sequel platform. Approximately 46.481 Gbp of raw micropathogen sequence data were obtained from samples from four different regions of Heilongjiang Province, China. The clean consensus sequences were compared with host sequences and filtered at 90% similarity. Most of the identified genomes represent previously unsequenced strains. The draft genomes contain an average of 397,746 proteins predicted to be associated with micropathogens, over 30% of which do not have an adequate match in public databases. In these data, Anaplasma phagocytophilum and Coxiella burnetii were detected in all samples, while Borrelia burgdorferi was detected only in Ixodes persulcatus ticks from G1 samples. Viruses are a key component of micropathogen populations. In the present study, Simian foamy virus, Pustyn virus and Crimean-Congo haemorrhagic fever orthonairovirus were detected in different samples, and more than 10-30% of the viral community in all samples comprised unknown viruses. Deep metagenomic shotgun sequencing has emerged as a powerful tool to investigate the composition and function of complex microbial communities. Thus, our dataset substantially improves the coverage of tick micropathogen genomes in public databases and represents a valuable resource for micropathogen discovery and for studies of tick-borne diseases.

RNAi-mediated silencing of Trichinella spiralis glutaminase results in reduced muscle larval infectivity.

Trichinella spiralis is an important foodborne parasitic nematode distributed worldwide that infects humans and animals. Glutaminase (GLS) is an important gene in the glutamine-dependent acid resistance (AR) system; however, its role in T. spiralis muscle larvae (ML) remains unclear. The present study aimed to characterize T. spiralis GLS (TsGLS) and assess its function in T. spiralis ML AR both in vitro and in vivo using RNA interference. The results indicated that native TsGLS (72 kDa) was recognized by anti-rTsGLS serum at the muscle larvae stage; moreover, an immunofluorescence assay confirmed that TsGLS was located in the epidermis of ML. After silencing the TsGLS gene, the relative expression of TsGLS mRNA and the survival rate of T. spiralis ML were reduced by 60.11% and 16.55%, respectively, compared to those in the PBS and control groups. In vivo AR assays revealed that the worm numbers at 7 and 35 days post-infection (dpi) decreased by 61.64% and 66.71%, respectively, compared to those in the PBS group. The relative expression of TsGLS mRNA in F1 generation T. spiralis ML was reduced by 42.52%, compared to that in the PBS group. To the best of our knowledge, this is the first study to report the presence of the glutamine-dependent AR system in T. spiralis. Our results indicate that TsGLS plays a crucial role in the T. spiralis AR system; thus, it could be used as a potential candidate target molecule for producing vaccines against T. spiralis infection.

First detection of Borrelia miyamotoi infections in ticks and humans from the northeast of Inner Mongolia, China.

Borrelia miyamotoi is a relapsing fever spirochete that can cause chills, fatigue, headache, myalgia, arthralgia, and even meningitis, damaging human health. B. miyamotoi has a wide distribution since its discovery in Ixodes persulcatus in 1994. The human B. miyamotoi disease was first described in Russia in 2011. However, the epidemiological information in China is limited. Here, we report the molecular detection of B. miyamotoi in the northeast of Inner Mongolia, China. A total of 774 adult ticks and 771 blood samples of patients were collected, from April 2017 to August 2019 in the northeast of Inner Mongolia, and tested for B. miyamotoi using real time-PCR. Gene sequences of 16S rRNA, fla, and glpQ were obtained to reconstruct the phylogenetic relationship of B. miyamotoi from humans and ticks. The results showed the total prevalence of B. miyamotoi in ticks was 1.3% of 774 ticks, with rates of 2.6% in I. persulcatus, 0.78% in Dermacentor nuttalli, 1.3% in D. silvarum, and 0.4% in Haemaphysalis longicornis. Thirteen (1.7%) patients were confirmed as positive for B. miyamotoi. Patients were mainly 50-60-years old and had a history of tick contact. They presented flu-like symptoms, including fever, headache, poor spirit, dizziness, nausea, vomiting, hypodynamic, chest distress, and myalgia. Phylogenetic analysis showed that the B. miyamotoi in the present study belonged to the Siberian type, distinct from European and American types and the I. ovatus isolate from Japan. This is the first report of B. miyamotoi detection in both ticks and humans in the northeast of Inner Mongolia, China, indicating B. miyamotoi is present in the area. These findings suggest that people have a risk of infection with B. miyamotoi in this region, where it should be included the differential diagnosis of tick-borne diseases.

Identification and biochemical characterisation of a novel methionine aminopeptidase from the taiga tick Ixodes persulcatus.

Methionine aminopeptidases (MetAPs), which remove the initiator methionine from nascent peptides, are essential in all organisms and considered to be a valuable targets for the treatment of various diseases, including cancer, malaria, and bacterial infections. However, MetAPs have not been reported in hard ticks (family Ixodidae), and their bioinformatics characterisation in tick's genome sequences is limited. In this study, we cloned, identified, and characterised a novel MetAP from Ixodes persulcatus, a vector for pathogens causing Lyme borreliosis and tick-borne encephalitis. The sequence analysis showed that I. persulcatus MetAP was a type 1 enzyme carrying C-terminal motifs conserved in the M24A family of metallopeptidases. Protein-protein docking simulations using human MetAP revealed conservation of substrate and metal-binding residues in the catalytic site cleft of the novel enzyme, which was designated IpMetAP. Recombinant IpMetAP expressed in Escherichia coli revealed its significant enzymatic activity with the synthetic substrate H-Met-4-methyl-coumaryl-7-amide at pH 7.5 with Km of 0.014 mM, kcat of 0.25 s-1, and overall catalytic efficiency (kcat/Km) of 18.36 mM-1 s-1. The activity of IpMetAP was enhanced by the addition of divalent cations Mn2+ and Co2+ and significantly inhibited by EDTA and bestatin. Site-directed mutagenesis of conserved amino acids indicated that the substitution of metal-binding residues D226 and H288 completely abolished the IpMetAP enzymatic activity, whereas that of the other sites had only moderate effects on substrate hydrolysis. The catalytic properties of IpMetAP suggest that the enzyme behaves similar to other MetAPs and such characterization expands our knowledge of aminopeptidases and protein metabolism of tick.

Trichinella spiralis Thioredoxin Peroxidase 2 Regulates Protective Th2 Immune Response in Mice by Directly Inducing Alternatively Activated Macrophages.

Trichinella infection can induce macrophages into the alternatively activated phenotype, which is primarily associated with the development of a polarized Th2 immune response. In the present study, we examined the immunomodulatory effect of T. spiralis thioredoxin peroxidase-2 (TsTPX2), a protein derived from T. spiralis ES products, in the regulation of Th2 response through direct activation of macrophages. The location of TsTPX2 was detected by immunohistochemistry and immunofluorescence analyses. The immune response in vivo induced by rTsTPX2 was characterized by analyzing the Th2 cytokines and Th1 cytokines in the peripheral blood. The rTsTPX2-activated macrophages (MrTsTPX2) were tested for polarization, their ability to evoke naïve CD4+ T cells, and resistance to the larval infection after adoptive transfer in BALB/c mice. The immunolocalization analysis showed TsTPX2 in cuticles and stichosome of T. spiralis ML. The immunostaining was detected in cuticles and stichosome of T. spiralis Ad3 and ML, as well as in tissue-dwellings around ML after the intestines and muscle tissues of infected mice were incubated with anti-rTsTPX2 antibody. Immunization of BALB/c mice with rTsTPX2 could induce a Th1-suppressing mixed immune response given the increased levels of Th2 cytokines (IL-4 and IL-10) production along with the decreased levels of Th1 cytokines (IFN-γ, IL-12, and TNF-α). In vitro studies showed that rTsTPX2 could directly drive RAW264.7 and peritoneal macrophages to the M2 phenotype. Moreover, MrTsTPX2 could promote CD4+ T cells polarized into Th2 type in vitro. Adoptive transfer of MrTsTPX2 into mice suppressed Th1 responses by enhancing Th2 responses and exhibited a 44.7% reduction in adult worm burden following challenge with T. spiralis infective larval, suggesting that the TsTPX2 is a potential vaccine candidate against trichinosis. Our study showed that TsTPX2 would be at least one of the molecules to switch macrophages into the M2 phenotype during T. spiralis infection, which provides a new therapeutic approach to various inflammatory disorders like allergies or autoimmune diseases.