PoCXCL8, a teleost chemokine, exerts direct bactericidal, chemotactic/phagocytic, and NETs releasing properties, promoting host anti-bacterial immunity.

As an important CXC chemokine, CXCL8 plays pleiotropic roles in immunological response. In teleost, CXCL8 is involved in cell migration and bacterial invasion. However, the immune antibacterial function of CXCL8 in Japanese flounder (Paralichthys olivaceus) (PoCXCL8) is largely scarce. In this research, we investigated the antibacterial property and leukocyte activation of PoCXCL8. PoCXCL8 consists of 100 amino acid residues, with a conserved chemokine CXC domain. PoCXCL8 was expressed in various tissues, with the highest level in liver and the lowest level in muscle, and sharply induced by V. harveyi or E. tarda in liver, spleen, and head kidney. In vitro, the recombinant PoCXCL8 (rPoCXCL8) could bind to Bacillus subtilis, Edwardsiella tarda, Escherichia coli, Pseudomonas fluorescens, Vibrio anguillarum, Vibrio harveyi, Staphylococcus aureus, and Micrococcus luteus, affect the growth of E. coli, E. tarda, M. luteus, and P. fluorescens, and have a direct bactericidal effect on E. coli and E. tarda. Moreover, rPoCXCL8 was able to bind the outer membranal protein rPilA of E. tarda. In addition, rPoCXCL8 could bind to PBLs, activating the PBLs activity including chemotaxis, proliferation, phagocytosis, reactive oxygen species, acid phosphatase activity. At same time, rPoCXCL8 could induce neutrophil to generate neutrophil extracellular traps (NETs) and promote the expression of inflammatory genes including IL-1ß, IL6, MMP13, TNF-α, and NF-κB. In flounder, the presence of rPoCXCL8 could enhance the in vivo resistance to E. tarda in liver, spleen, and head kidney. Moreover, the PoCXCL8-deficient could attenuate the fish defense against E. tarda infection in in spleen and head kidney. In conclusion, these results provided new insights into the antibacterial properties of CXCL8 in P. olivaceus.

PoIL8-L, a teleost interleukin-8 like, enhances leukocyte cellular vitality and host defense against bacterial infections in Japanese flounder (Paralichthys olivaceus).

Interleukin-8 (IL-8), a CXC chemokine, exerts pivotal effect on cell migration, inflammatory response, and immune regulation. In this study, we examined the immunological characteristics of an IL-8 like homologue (PoIL8-L) in Japanese flounder (Paralichthys olivaceus). PoIL8-L contains a conserved chemokine CXC domain and 105 amino acid residues. PoIL8-L expression in tissues was constitutive, and significantly regulated by V. havieri or E. tarda infection. In vitro, rPoIL8-L could bind to eight tested bacteria, exhibited bacteriostatic and bactericidal effects against certain bacteria, and could bind to the targeted bacterial Ⅳ pilin protein rPilA of E. tarda. Furthermore, rPoIL8-L could attach to peripheral blood leukocytes, and enhance their immune genes expression, respiratory burst, chemotaxis, proliferation, acid phosphatase activity, and phagocytic activity. Additionally, rPoIL8-L induce neutrophils to extrude neutrophil extracellular traps. In vivo, rPoIL8-L could promote host resistance to E. tarda infection. In summary, these findings provide fresh perspectives on the immunological antibacterial properties of IL-8 in teleost.

Rational design of an AIEgen for imaging lipid droplets polarity change during ferroptosis.

Ferroptosis can regulate cell death by accumulating lipid peroxides, affecting the structure and polarity of lipid droplets (LDs), but clear evidence is still lacking. Fluorescence imaging is the most powerful technique for studying LDs' function. However, developing AIE fluorescent probes with high selectivity and sensitivity for targeting LDs remains challenging. In this study, we rationally designed an AIEgen, as a novel fluorescent probe TPE-BD, by constructing a push-pull electron structure. The probe has benzo[b]thiophene-3(2H)-one 1,1-dioxide as the electron acceptor, tetraphenylethylene (AIE skeleton) as the electron donor, and thiophene as the bridging group. The optical performance of probe TPE-BD indicated that the UV-visible absorption spectrum of the probe was minimally affected by solvent polarity (except for glycerol and PBS solvents), but the fluorescence of probe is very sensitive to changes in polarity, achieving the goal of polarity detection in LDs. CCK-8 assay and cell imaging experiments demonstrated that probe TPE-BD exhibited good cell compatibility and effectively targeted LDs, enabling the monitoring of LDs' polarity and quantity during ferroptosis.

The Relationship between Viral Replication and the Severity of Hepatic Necroinflammatory Damage Changed before HBeAg Loss in Patients with Chronic Hepatitis B Virus Infection.

Background and Aims: Disease progression of chronic hepatitis B virus (HBV) infection is driven by the interactions between viral replication and the host immune response against the infection. This study aimed to clarify the relationship between HBV replication and hepatic inflammation during disease progression. Methods: Two cross-sectional, one validation cohort, and meta-analyses were used to explore the relationship between HBV replication and liver inflammation. Spearman analysis, multiple linear regression, and logistic regression were used to explore the relationship between variables. Results: In the cross-sectional cohorts A and B including 1,350 chronic hepatitis B patients, Spearman analysis revealed a negative relationship between HBV replication (such as HBV DNA) and liver inflammation (such as ALT) in HBeAg-positive patients with higher HBV DNA >2×106 IU/mL (rho=-0.160 and -0.042) which turned to be positive in HBeAg-positive patients with HBV DNA ≤2×106 IU/mL (rho=0.278 and 0.260) and HBeAg-negative patients (rho=0.450 and 0.363). After adjustment for sex, age, and anti-HBe, results from logistic regression and multiple linear regression showed the opposite relationship still existed in HBeAg-positive patients with different DNA levels; the opposite relationship in HBeAg-positive patients with different DNA levels was validated in a third cohort; the opposite relationship in patients with different HBeAg status was partially confirmed by meta-analysis (overall R: -0.004 vs 0.481). Conclusions: These results suggested a negative relationship between viral replication and liver inflammation in HBeAg-positive patients with high HBV DNA, which changed to a positive relationship for those HBeAg-positive patients with DNA less than 2×106 IU/mL and HBeAg-negative patients.

CsIL-20, a tongue sole interleukin-20, negatively mediates leucocyte activity and antibacterial defense.

Interleukin-20 (IL-20), as an essential member of IL-10 family, plays vital roles in mammalian immunological response such as antimicrobial, inflammation, hematopoiesis, and immune diseases. In teleost, the study about immune antimicrobial function of IL-20 is largely scarce. In this article, we revealed the expression profiles and the immunological functions of the IL-20 (CsIL-20) in tongue sole Cynoglossus semilaevis. CsIL-20 is composed of 183 amino acid residues, with seven cysteine residues and a typical IL-10 domain which comprises six α-helices and two ß-sheets, and shares 34.4-71.2 % identities with other teleost IL-20. CsIL-20 was constitutively expressed in a variety of tissues and regulated by bacterial invasion, and the recombinant CsIL-20 (rCsIL-20) could bind to different bacteria. In vitro rCsIL-20 could interact with the membrane of peripheral blood leukocytes (PBLs), leading to the attenuation of reactive oxygen species (ROS) production and acid phosphatase activity in PBLs. In line with In vitro results, In vivo rCsIL-20 could obviously suppressed the host immune against bacterial infection. Furthermore, knockdown of CsIL-20 in vivo could markedly enhance the host antibacterial immunity. Collectively, these observations offer new insights into the negative effect of CsIL-20 on antibacterial immunity.

Two novel teleost calreticulins PoCrt-1/2, with bacterial binding and agglutination activity, are involved in antibacterial immunity.

Calreticulin (Crt), a conserved lectin-like pleiotropic protein, plays crucial roles in mammalian immune response. In fish, the immunological function of Crt is limited investigated. Herein, we studied the antibacterial immunity of two type of Crt homologues (i.e. PoCrt-1 and PoCrt-2) in Japanese flounder (Paralichthys olivaceus). PoCrt-1 and PoCrt-2 are composed of 419 and 427 amino acid residues respectively, with 69.09% overall sequence identities with each other. Both PoCrt-1 and PoCrt-2 contain a signal peptide and three functional domains i.e. N-, P- and C-domains. Both PoCrt-1 and PoCrt-2 were constitutively expressed at various tissues with highest expression level in liver, and obviously regulated by Edwardsiella tarda and Vibrio harveyi. Furthermore, recombinant PoCrt-1 and PoCrt-2 (rPoCrt-1 and rPoCrt-2) could bind to different Gram-negative bacteria with highest binding index with E. tarda. At same time, in vitro rPoCrt-1 and rPoCrt-2 could agglutinate E. tarda, V. harveyi, and Vibrio anguillarum, and inhibit the bacterial growth. Similarly, in vivo rPoCrt-1 and rPoCrt-2 could significantly suppress the dissemination of E. tarda. Overall, these observations add new insights into the antibacterial immunity of Crt in P. olivaceus.

Nano-pesticide carrier O-Carboxymethyl chitosan is indigestible in Apis cerana cerana and affects intestinal flora.

O-Carboxymethyl chitosan nanoparticles (O-CMC-NPs), which are organic pesticide carriers, have excellent application potential. Exploring the effects of O-CMC-NPs on non-target organisms, such as Apis cerana cerana, is critical for their effective application; however, such studies are limited. This study investigated the stress response of A. cerana Fabricius after O-CMC-NPs ingestion. The administration of high O-CMC-NP concentrations enhanced the activities of antioxidant and detoxifying enzymes in A. cerana, with the activity of glutathione-S-transferase increasing by 54.43 %-64.33 % after one day. The transit of O-CMC-NPs into the A. cerana midgut resulted in their deposition and adherence to the intestinal wall, as they cluster and precipitate in acidic conditions. The population of Gillianella bacteria in the middle intestine was remarkably reduced after 6 d of administration of high O-CMC-NP concentrations. Contrastingly, the abundance of Bifidobacteria and Lactobacillus in the rectum significantly increased. These results indicate that the intake of high concentrations of O-CMC-NPs causes a stress response in A. cerana and affects the relative abundance of crucial intestinal flora, which may pose a potential risk to the colony. This implies that even nanomaterials with favorable biocompatibility should be applied reasonably within a specific range to avoid adverse effects on the environment and non-target organisms in the context of large-scale research and promotion of nanomaterials.

Nanoscale Thermal Strain Engineering-Driven Ferroelastic Domain Evolution in CH3NH3PbI3 Perovskites.

A local thermal strain engineering approach via an ac-heated thermal probe was incorporated into methylammonium lead triiodide (MAPbI3) crystals and acts as a driving force for ferroic twin domain dynamics, local ion migration, and property tailoring. Periodically, striped ferroic twin domains and their dynamic evolutions were successfully induced by local thermal strain and high-resolution thermal imaging, giving decisive evidence of the ferroelastic nature in MAPbI3 perovskites at room temperature. Local thermal ionic imaging and chemical mappings demonstrate that domain contrasts are from local methylammonium (MA+) redistribution into the stripes of chemical segregation in response to the local thermal strain fields. The present results reveal an inherent coupling among local thermal strains, ferroelastic twin domains, local chemical-ion segregations, and physical properties and offer a potential path to improve the functionality of metal halide perovskite-based solar cells.

Effect of Cu on the Formation of Reversed Austenite in Super Martensitic Stainless Steel.

We investigated the effect of Cu on the formation of reversed austenite in super martensitic stainless steel by using X-ray diffraction (XRD), a transmission electron microscope (TEM) and an energy-dispersive spectrometer (EDS). Our results showed that the microstructure of the steels comprised tempered martensite and diffused reversed austenite after the steels were quenched at 1050 °C and tempered at 550-750 °C. The volume fraction of reversed austenite in the steel with 3 wt.% of Cu (3Cu) was more than that with 1.5 wt.% of Cu (1.5Cu). The transmission electron microscope results revealed that the reversed austenite in 1.5Cu steel mainly had the shape of a thin strip, while that in 3Cu steel had a block shape. The nucleation points and degree of Ni enrichment of reversed austenite in 3Cu steel were higher than those in 1.5Cu steel. The reversed austenite was more likely to grow in ε-Cu enriched regions. Therefore, Cu can promote reversed austenite nucleation and growth. The mechanical properties of 3 Cu steel are obviously better than those of 1.5Cu steel when tempered at 550-650 °C.

Rational design of graphite carbon nitride-decorated zinc oxide nanoarrays on three-dimensional nickel foam for the efficient production of reactive oxygen species through stirring-promoted piezo-photocatalysis.

Stirring-promoted piezo-photocatalysis based on a three-dimensional foam architecture has great potential applications in wastewater treatment and water splitting. However, the detailed mechanism of stirring-promoted piezo-photocatalysis has not been quantitatively studied, and the utilization of visible light needs to be further improved. In this work, the high solar-driven piezo-photocatalytic ability of graphite carbon nitride (g-C3N4)-decorated zinc oxide (ZnO) nanoarrays on nickel (Ni) foam is experimentally achieved and first simulated by the finite element method (FEM). The water flow velocity, depending on the stirring rate, is significantly increased by turbulence-induced fluid eddies while flowing through 3D macropores and nanoarrays, resulting in higher piezoelectricity. Reactive oxygen species (ROS) are experimentally examined by the electron spin resonance (ESR) technique and theoretically calculated by density functional theory (DFT) to confirm the configurations of the heterojunction under photocatalysis and piezo-photocatalysis. In particular, the large enhancement of 1O2 generation suggests the potential of piezo-photocatalysis in biological applications. The mechanism of piezo-photocatalysis is proposed in which the S-scheme heterojunction is realized by piezoelectricity to improve photocatalysis by retaining high redox ability and inhibiting recombination. This work provides a possible approach to harvesting energy sources for piezoelectricity and expands the scope of solar-driven piezo-photocatalysis.

Effects of sublethal azadirachtin on the immune response and midgut microbiome of Apis cerana cerana (Hymenoptera: Apidae).

As a wildly used plant-derived insecticide, azadirachtin (AZA) is commonly reported as harmless to a range of beneficial insects. However, with the research on the effect of AZA against pollinators in recent years, various negative physiological effects on other Apidae species have been demonstrated. Thus to explore the safety of azadirachtin to Apis cerana cerana, the different physiological effects of sublethal concentration of azadirachtin on worker bees A.c.cerana has been studied. With the exposure of 5 mg·L-1 and 10 mg·L-1 azadirachtin for 5 d, the relative expression of Apidaecin, Abaecin and Lysosome genes in workers has decreased significantly at 1, 2,3 and 5 d, and the mRNA levels of Defensin 2 and Hymenoptaecin were also significantly inhibited by 10 mg·L-1 azadirachtin at each check point. Besides, the activity of midgut antioxidant enzymes Superoxide Dismutase (SOD) and Catalase (CAT) which are the first line of defence in antioxidant systems was not affected by AZA, the activity of Peroxidase (POD) showed a fluctuating pattern at 24 h and 48 h, while the activity of polyphenol oxidase (PPO) has significantly inhibited by AZA. However, through 16sRNA analysis it was observed that 5 mg·L-1 AZA did not affect the midgut microbiome colony composition and relative abundance, as well as its main function. Therefore, to a certain extent, azadirachtin is safe for workers, but we should pay more attention to the sublethal effect of AZA that also detrimental to the healthy development of the honeybee colony.

Enhanced Control of the Fungus Gnat Bradysia odoriphaga (Diptera: Sciaridae) by Co-Application of Clothianidin and Hexaflumuron.

The fungus gnat is a major pest of chive in China. Its control has been relied heavily on the application of clothianidin. Due to the intensive application, its control efficacy become reduced. The present study was intended to evaluate co-drenching of clothianidin with hexaflumuron on absorption and dissipation of clothianidin in chive plants and soils and determine the effect of such application on control efficacies. Chive production fields in Guangdong and Hubei Provinces were drenched with clothianidin alone and a mixture of clothianidin and hexaflumuron at low application rates. Concentrations of clothianidin in chive plants and soils were analyzed by HPLC. Results showed that co-application had higher control efficacies against the fungus gnat than clothianidin alone. The co-application enhanced clothianidin absorption and dissipation and extended the half-lives of clothianidin in chive. It was likely that hexaflumuron protected chive roots from larva damage, and healthy roots absorbed more clothianidin, resulting in the extension of the half-lives. Additionally, the terminal residues of clothianidin in chive after 14 days of application were lower than the maximum residue limit in chive set by the Codex Alimentarius Commission. This study for the first time documented that co-application of clothianidin and hexaflumuron improved chive plants in absorption and dissipation of clothianidin and enhanced fungus gnat control efficacies.

Examination of acephate absorption, transport, and accumulation in maize after root irrigation for Spodoptera frugiperda control.

Since the invasion of the fall armyworm moth (Spodoptera frugiperda) in China in January 2019, damage to maize crops has gradually intensified, and chemical control has become the main control measure. This study aimed to examine methods of effective pest control while monitoring the environmental impact of pesticide use. The effectiveness of S. frugiperda pest control by foliar spraying and root irrigation of maize plants with acephate was determined, and the absorption, distribution, and dissipation of acephate and methamidophos by maize were studied. Field trials showed that acephate treatment at 6000 g a.i. ha-1 was the most effective for controlling S. frugiperda. Acephate and methamidophos were absorbed from the roots, transported upward, and concentrated in the leaves, particularly new leaves. The terminal residues of acephate and methamidophos in maize grains were below detectable levels at 60 days after treatment. The results demonstrate that acephate treatment via root irrigation can more effectively control the infestation of S. frugiperda in maize than acephate treatment via foliar spraying. The translocation and distribution of acephate and methamidophos by root irrigation were more uniform, and the holding efficiency was higher than those in foliar spraying, suggesting an extended period of control efficacy. This pest control method could be utilized to reduce pesticide residues while safely and efficiently controlling S. frugiperda infestation.

Preparation of alginate-chitosan floating granules loaded with 2-methyl-4-chlorophenoxy acetic acid (MCPA) and their bioactivity on water hyacinth.

BACKGROUND: Water hyacinth (Eichhornia crassipes) is considered the most damaging aquatic weed in many countries. Chemical methods are still the primary approach to control, although this directly exposes the natural enemy of water hyacinth (water hyacinth weevil) to herbicides. In addition, spray drift can easily damage non-target plants. In this study, herbicides, natural polymer materials (chitosan and carboxymethyl chitosan), sodium alginate and natural oils (citronella oil) were used to prepare novel floating polysaccharide granules as a solution for controlling water hyacinth. RESULTS: 2-Methyl-4-chlorophenoxy acetic acid (MCPA) floating granules with a spherical structure were prepared using a MCPA-chitosan-sodium alginate-oil cross-linking and embedding method. The granules produced showed the required properties of floatation and slow controlled herbicide release. In addition, the polysaccharide granules collected around water hyacinth plants and enabled targeted release of the active herbicide ingredients onto the stems and roots of the weed, thereby stopping the herbicide from reaching non-target plants and preventing regrowth of water hyacinth. CONCLUSION: We successfully prepared highly effective MCPA-loaded floating granules, which compared with an MCPA solution, exerted greater control on water hyacinth. Concomitantly, these granules provide a solution to spray drift and ensure the safety of natural enemies of water hyacinth, which is of great significance in research on herbicide formulations.

AFM-IR probing the influence of polarization on the expression of proteins within single macrophages.

Macrophages are essential in innate immunity and are involved in a variety of biological functions. Due to high plasticity, macrophages are polarized in different phenotypes depending on different microenvironments to perform specific functions. Although many studies have focused on macrophage polarization, few have explored the polarization characteristics of macrophages at the subcellular level, even at nanoscale resolution. Here, we utilize AFM-based infrared spectroscopy (AFM-IR) to investigate the influence of an inducer on the expressed proteins of M1/M2 macrophages (induced by LPS and IL-13, respectively). The results from AFM-IR combined with principal component analysis revealed that the characteristic proteins within M1 contain about 35% antiparallel ß-sheets (due to the high expression of TNF-α), while the proteins within M2 are made up of approximately 38.8% α-helices. The corresponding nanoscale chemical mapping demonstrates a remarkably heterogeneous distribution of expressed proteins inside single macrophages. Beside the biochemical properties, the biomechanical properties of macrophages were found to be softened in response to the polarization process.

Potential High-Temperature Piezoelectric Ceramics with Remarkable Performances Enhanced by the Second-Order Jahn-Teller Effect.

Herein, the second-order Jahn-Teller effect was applied to the design of the bismuth ferrite-based ceramics. A large distortion of an electron structure arranged along the z axis and an asymmetric distribution of charge density were calculated in 0.80(0.725BiFeO3-0.275BaTiO3)-0.20PT (0.20 PT) based on the density functional theory, indicating good ferro/piezoelectric properties. The top experimental polarization of 36.89 µC/cm2, optimal d33 value of 258 pC/N measured at room temperature, and ultrahigh d33 value of 303 pC/N measured at 370 °C were obtained at 0.20 PT, thereby further confirming the calculations. Furthermore, a high Curie point of 488 °C, as well as outstanding temperature stability ranging from room temperature to 430 °C of the 0.20 PT ceramic was observed. The domain of the 0.20 PT exhibited greater order and smaller size, resulting in easy switching when applying voltage. The distorted electron structure, plumb grains, ordered and easily switchable domains, and coexistences of tetragonal (T) and rhombohedral (R) phases contributed to the large piezoelectric constant of the 0.2 PT ceramic. BFBT-xPT ceramics are potentially promising for high-temperature piezoelectric field applications.

Influence of Oxygen Pressure on the Domain Dynamics and Local Electrical Properties of BiFe0.95Mn0.05O3 Thin Films Studied by Piezoresponse Force Microscopy and Conductive Atomic Force Microscopy.

In this work, we have studied the microstructures, nanodomains, polarization preservation behaviors, and electrical properties of BiFe0.95Mn0.05O3 (BFMO) multiferroic thin films, which have been epitaxially created on the substrates of SrRuO3, SrTiO3, and TiN-buffered (001)-oriented Si at different oxygen pressures via piezoresponse force microscopy and conductive atomic force microscopy. We found that the pure phase state, inhomogeneous piezoresponse force microscopy (PFM) response, low leakage current with unidirectional diode-like properties, and orientation-dependent polarization reversal properties were found in BFMO thin films deposited at low oxygen pressure. Meanwhile, these films under high oxygen pressures resulted in impurities in the secondary phase in BFMO films, which caused a greater leakage that hindered the polarization preservation capability. Thus, this shows the important impact of the oxygen pressure on modulating the physical effects of BFMO films.