A wide star-black-hole binary system from radial-velocity measurements.

All stellar-mass black holes have hitherto been identified by X-rays emitted from gas that is accreting onto the black hole from a companion star. These systems are all binaries with a black-hole mass that is less than 30 times that of the Sun1-4. Theory predicts, however, that X-ray-emitting systems form a minority of the total population of star-black-hole binaries5,6. When the black hole is not accreting gas, it can be found through radial-velocity measurements of the motion of the companion star. Here we report radial-velocity measurements taken over two years of the Galactic B-type star, LB-1. We find that the motion of the B star and an accompanying Hα emission line require the presence of a dark companion with a mass of [Formula: see text] solar masses, which can only be a black hole. The long orbital period of 78.9 days shows that this is a wide binary system. Gravitational-wave experiments have detected black holes of similar mass, but the formation of such massive ones in a high-metallicity environment would be extremely challenging within current stellar evolution theories.

Preparation of hyaluronic acid-loaded liquid-core hydrogel beads with acceptable mechanical properties and thermal stability.

BACKGROUND: Hyaluronic acid liquid-core hydrogel beads (HA-LHB) is a good way for oral intake of HA. However, HA may affect the reaction-diffusion of sodium alginate (SA) and Ca2+ leading to poor mechanical properties, since HA is a polyanionic electrolyte having electrostatic effect and a certain spatial site-blocking effect. RESULTS: The mechanical properties of HA-LHB were modified from bathing solution, core solution and secondary calcium bath time. The mechanical properties varied with the SA structure and concentration in bathing solution, where SA with high G (guluronic acid) segment compounded with SA with high M (mannuronic acid) segment at a mass ratio of 7:3 with a 11 g kg-1 concentration showed the best mechanical properties. The secondary calcium bath can greatly improve the mechanical properties due to the tight network formed by bidirectional crosslinking, and 15 min reaction reached the plateau if Ca2+ is sufficient. And the mechanical properties were positively correlated with calcium lactate concentration only at <70 g kg-1 in core solution, but the diffusion of Ca2+ was hindered by the tight gel network at higher concentrations. Moreover, the mechanical properties can be maintained during heat treatment, due to the rearrangement of alginate network structure. CONCLUSION: Our results suggested that the problem of poor mechanical properties of LHB in the presence of high HA concentration can be avoided by process control, which may broaden the development of HA and popping boba market. © 2024 Society of Chemical Industry.

Energetic eruptions leading to a peculiar hydrogen-rich explosion of a massive star.

Every supernova so far observed has been considered to be the terminal explosion of a star. Moreover, all supernovae with absorption lines in their spectra show those lines decreasing in velocity over time, as the ejecta expand and thin, revealing slower-moving material that was previously hidden. In addition, every supernova that exhibits the absorption lines of hydrogen has one main light-curve peak, or a plateau in luminosity, lasting approximately 100 days before declining. Here we report observations of iPTF14hls, an event that has spectra identical to a hydrogen-rich core-collapse supernova, but characteristics that differ extensively from those of known supernovae. The light curve has at least five peaks and remains bright for more than 600 days; the absorption lines show little to no decrease in velocity; and the radius of the line-forming region is more than an order of magnitude bigger than the radius of the photosphere derived from the continuum emission. These characteristics are consistent with a shell of several tens of solar masses ejected by the progenitor star at supernova-level energies a few hundred days before a terminal explosion. Another possible eruption was recorded at the same position in 1954. Multiple energetic pre-supernova eruptions are expected to occur in stars of 95 to 130 solar masses, which experience the pulsational pair instability. That model, however, does not account for the continued presence of hydrogen, or the energetics observed here. Another mechanism for the violent ejection of mass in massive stars may be required.

Difenoconazole causes spleen tissue damage and immune dysfunction of carp through oxidative stress and apoptosis.

As the use of pesticides increases year after year, so does the level of residual pesticides in the aquatic environment, posing a serious threat to non-target organisms. Difenoconazole (DFZ), a class of long-lasting fungicides and residues in the marine environment, has been shown to cause damaging effects on different organs of aquatic organisms. However, there is no research on the damage of DFZ to carp spleen tissue. This study aimed to investigate the acute toxic effects of DFZ on the spleen tissue of carp (Cyprinus carpio) by exposing juvenile carp to environmentally relevant concentrations of DFZ. We randomly selected 30 carp, divided them into the Control, Low, and High groups, and then exposed the three groups to 0, 0.488 mg/L DFZ, and 1.953 mg/L DFZ for 96 h respectively. We then investigated the toxic effects caused by DFZ on carp and spleen tissues by detecting changes in spleen histopathologic damage, apoptosis, oxidative stress, inflammation, and blood biochemical parameters. We found that DFZ causes severe histopathology in spleen tissue, including ballooning, structural relaxation, and giant mitochondria. In addition, we found that DFZ caused excessive apoptosis in spleen tissue by TUNEL staining and expression levels of apoptosis-related genes (caspase3, caspase8, caspase9, fas, bax, bcl-2, and p53). The activities and transcript levels of the antioxidant enzymes SOD, CAT, and GSH-Px were significantly down-regulated. In addition, DFZ led to a significant increase in activation of the NF-κB signaling pathway and mRNA levels of pro-inflammatory cytokines il-6, il-1ß, and tnf-α, and a substantial decrease in mRNA levels of anti-inflammatory cytokines il-10 and tgf-ß1 in spleen tissue. Blood biochemical parameters showed that DFZ exposure significantly reduced erythrocyte, leukocyte, hemoglobin, C3, and IgM levels. Collectively, DFZ exposure induced apoptosis, immunosuppression, oxidative stress, and inflammatory responses in the spleen tissue of carp, resulting in spleen tissue damage.

Avermectin induces carp neurotoxicity by mediating blood-brain barrier dysfunction, oxidative stress, inflammation, and apoptosis through PI3K/Akt and NF-κB pathways.

Avermectin, a "low toxicity insecticide", has been widely used in recent years, but its non-target toxicity, especially to aquatic organisms, has been neglected. In this study, we evaluated the neurotoxic effects of avermectin on carp by establishing a 96 h avermectin acute toxicity test, and its possible mechanism was discussed. The 96 h LC50 of avermectin in carp was found to be 24.04 µg/L. Therefore, 3.005 µg/L and 12.02 µg/L were used as the low-dose and high-dose groups, respectively, to investigate the neurotoxic effects of avermectin on carp. The results of high-performance liquid chromatography (HPLC) analysis showed that avermectin accumulated in the carp brain. Histopathological observation and immunohistochemical analysis (IHC) of TNF-α and Bax showed that avermectin exposure led to inflammatory cell infiltration and neuronal necrosis. The mRNA levels of tight junction genes and the IHC results of ZO-1 and Occludin showed that the structure of the blood-brain barrier (BBB) was destroyed. Biochemical analysis showed that avermectin induced the accumulation of MDA in the brain and decreased the activity of antioxidant enzymes CAT and SOD, leading to oxidative stress. In addition, avermectin induces brain inflammation by activating NF-κB pathway and releasing inflammatory factors IL-1ß, IL-6, TNF-α and iNOS. TEM and TUNEL assays showed that exposure to avermectin induced apoptosis in brain. what is more, the expression of apoptosis-related genes and proteins suggested that avermectin-induced apoptosis may be associated with inhibition of the PI3K/Akt signaling pathway. This study also showed that avermectin-induced NF-κB signaling activation was partially dependent on its upstream PI3K/Akt signaling pathway. Therefore, this study concludes that avermectin can induce neurotoxicity in carp by disrupting the blood-brain barrier structure and generating oxidative stress, inflammation, and apoptosis and that NF-κB and PI3K/Akt signaling pathways are involved in this process.

Difenoconazole disrupts the blood-brain barrier and results in neurotoxicity in carp by inhibiting the Nrf2 pathway mediated ROS accumulation.

Excessive use of hard-to-degrade pesticides threatens the ecological health of aquatic systems. This study aimed to investigate difenoconazole (DFZ) residues in the environment induced neurotoxicity in carp and the underlying mechanisms. A total of thirty-six carps were divided into three groups and exposed to 0, 0.5, and 2.0 mg/L DFZ for 96 h, respectively. The alterations in behavior and blood-brain barrier (BBB) were examined, and potential mechanisms were explored using immunological assays and biochemical methods. The results showed that DFZ exposure caused behavioral freezing, reduced feeding, and neuronal necrosis in carp. Mechanistically, DFZ triggered ROS accumulation and destroyed the balance between oxidation and antioxidation with increased lipid peroxidation product MDA contents and reduced antioxidant enzymes SOD and CAT activities in the carp brain by inhibiting the NF-E2-related factor 2 (Nrf2) pathway. The activation of oxidative stress further reduced tight junction proteins and MMP levels, thereby destroying BBB and leading to DFZ leakage into the brain. Increased BBB permeability additionally led to DFZ activation of nuclear factor kappa-B signaling-mediated inflammatory cytokine storm, exacerbating neuroinflammation. Meanwhile, DFZ exposure activated mitochondria-associated apoptosis in the carp's brain by up-regulating Bcl-2 associated X protein, cleaved-caspase3, and cytochrome C and decreasing B-cell lymphoma-2 levels. Interestingly, the carp's brain initiated a protective autophagic response via the PI3K/AKT/TOR pathway intending to counteract the neurotoxicity of DFZ. Overall, we concluded that accumulation of DFZ at high concentrations in the aquatic systems disrupted the BBB and resulted in neurotoxicity in carp through inhibition of Nrf2 pathway-mediated ROS accumulation. This study provides a reference for monitoring DFZ residues in the environment and a new target for the treatment of DFZ-induced neurotoxicity in carp.

Non-target toxic effects of avermectin on carp spleen involve oxidative stress, inflammation, and apoptosis.

Avermectin is one of the most widely used pesticides, but its toxicity to non-target organisms, especially aquatic organisms, has been ignored. Therefore, an acute spleen injury model of avermectin in carp was established to assess the non-target toxicity of avermectin to carp. In this study, 3.005 µg/L and 12.02 µg/L were set as the low and high dose groups of avermectin, respectively, and a four days acute exposure experiment was conducted. Pathological structure observation showed that avermectin damaged spleen tissue structure and produced inflammatory cell infiltration. Biochemical analysis showed that avermectin significantly reduced the activities of antioxidant enzymes CAT, SOD, and GSH-px, but increased the content of MDA, a marker of oxidative damage. Avermectin exposure also significantly increased the transcription levels of inflammatory cytokines such as IL-1ß, IL-6, TNF-α, and INOS, and also significantly enhanced the activity of the inflammatory mediator iNOS, but suppressed the transcription levels of anti-inflammatory factors TGF-ß1 and IL-10. In addition, TUNEL detected that the apoptosis rate increased significantly with the increase of avermectin dosage, and the transcription levels of apoptosis-related genes BAX, P53, and Caspase 3/9 also increased in a dose-dependent manner. This study is preliminary evidence that avermectin induces spleen injury in carp through oxidative stress, inflammation, and apoptosis, which has important implications for subsequent studies on the effects of avermectin on non-target organisms.

NLRP3 inflammasome signal pathway involves in Vibrio harveyi-induced inflammatory response in murine peritoneal macrophages in vitro.

Vibrio harveyi, an important zoonotic pathogen, can infect wounds and cause inflammatory response. Understanding the inflammatory response pathways could facilitate the exploration of molecular mechanisms for treating V. harveyi infection. NLR family pyrin domain-containing 3 (NLRP3) inflammasome is involved in the interaction between hosts and pathogenic microorganisms and could be sensed by various pathogen-associated molecular patterns (PAMPs) or damage-associated molecular patterns (DAMPs). Nonetheless, the function of NLRP3 inflammasome in V. harveyi infection remains unclear. In the present study, we established a V. harveyi infection model using murine peritoneal macrophages (PMs). Various techniques, including western blot analysis, enzyme-linked immunosorbent assay (ELISA), RT-qPCR, immunofluorescence, and inhibition assays, were used to explore the molecular mechanism of V. harveyi-induced inflammation. The results showed that many inflammatory cytokines participated in V. harveyi infection, with interleukin (IL)-1ß being the most abundant. Pan-caspase inhibitor pretreatment significantly decreased the secretion of IL-1ß in murine PMs. Moreover, the identification of V. harveyi involved a large number of NLR molecules, especially the NLRP3 receptor, and further studies revealed that NLPR3 inflammasome was activated by V. harveyi infection, as evidenced by puncta-like NLRP3 surrounding cell nuclear, ASC specks in the nucleus and cytoplasm, and ASC oligomerization. Inhibition of NLRP3 inflammasome impaired the release of mature IL-1ß in V. harveyi-infected murine PMs. Furthermore, blocking the secretion of mature IL-1ß could markedly decrease the release of other proinflammatory cytokines, including IL-6, IL-12, and tumor necrosis factor-α. Overall, these data indicated that NLRP3 inflammasome was activated in response to V. harveyi infection and enhanced inflammatory response by promoting IL-1ß secretion in murine PMs.

Molecular mechanism of kidney damage caused by abamectin in carp: Oxidative stress, inflammation, mitochondrial damage, and apoptosis.

Indiscriminate use of pesticides not only leads to environmental pollution problems, but also causes poisoning of non-target organisms. Abamectin (ABM), a widely used insecticide worldwide, is of wide concern due to its persistence in the environment and its high toxicity to fish. The kidney, as a key organ for detoxification, is more susceptible to the effects of ABM. Unfortunately, few studies investigated the mechanisms behind this connection. In this study, carp was used as an indicator organism for toxicological studies to investigate renal damage caused by ABM residues in carp. In this work, carp were exposed to ABM (0, 3.005, and 12.02 µg/L) for 4 d and the nephrotoxicity was assessed. Histopathological findings revealed that ABM exposure induced kidney damage in carp, as well as an increase Creatinine and BUN levels. Meanwhile, ABM as a reactive oxygen species (ROS) stimulator, boosted ROS bursts and lowered antioxidant enzyme activity while activating the body's antioxidant system, the Nrf2-Keap1 signaling pathway. The accumulation of ROS can also lead to the imbalance of the body's oxidation system, leading to oxidative stress. At the same time, NF-κB signaling pathway associated with inflammation was activated, which regulated expression levels of inflammatory cytokines (TNF-α, IL-6, IL-1ß, and iNOS increased, while IL-10 and TGF-ß1 decreased). In addition, ABM exposure caused structural damage to kidney mitochondria of carp, resulting in decreased mitochondrial membrane potential and ATP production capacity, and mediated apoptosis through endogenous pathways Bax/Bcl-2/Caspase-9/Caspase-3. In conclusion, ABM caused kidney damage in carp by inducing oxidative stress, inflammation, and apoptosis through mitochondrial pathway. These findings will be useful for future research into molecular mechanisms of ABM-induced nephrotoxicity in aquatic organisms.

Hepatotoxicity of the Pesticide Avermectin Exposure to Freshwater-Farmed Carp: Evidence from In Vivo and In Vitro Research.

Avermectin (AVM) is presently one of the most extensively employed insecticides across the globe. A number of toxicity research studies of AVM have been carried out in freshwater-farmed carp; however, there are currently no toxicity studies on the liver. This investigation aims to replicate an acute liver injury model induced by AVM in carp, subsequently analyzing the adverse effects imposed on the nontarget species while delving into potential mechanisms underlying its toxicity. In this study, we found that AVM-exposed carp liver tissue showed cellular hydration degeneration and necrosis and reduced the viability of hepatocyte L8824. Second, AVM induced oxidative stress in carp, and AVM stimulation led to reactive oxygen species (ROS) accumulation and Ca2+ overload in hepatocyte L8824, suggesting that AVM exposure induces mitochondrial dysfunction in hepatocytes. AVM induced inflammation in carp liver tissue by inducing mitochondrial kinetic disruption, which triggered hepatic tissue injury. AVM induced autophagy and apoptosis in carp liver tissue and ROS mediated AVM-induced autophagy and apoptosis. The formation of autophagy attenuated the AVM-induced liver injury. In conclusion, the present study elucidated the hepatotoxicity and potential mechanisms of freshwater aquaculture carp exposed to the pesticide AVM, emphasized the importance of monitoring pesticide AVM contamination in freshwater aquaculture aquatic environments, and provided theoretical references for the targeted prevention of AVM-induced toxicity in carp.

Absorption, metabolism, and functions of hyaluronic acid and its therapeutic prospects in combination with microorganisms: A review.

Hyaluronic acid (HA) is key to the stability of the internal environment of tissues. HA content in tissues gradually decreases with age, causing age-related health problems. Exogenous HA supplements are used to prevent or treat these problems including skin dryness and wrinkles, intestinal imbalance, xerophthalmia, and arthritis after absorption. Moreover, some probiotics are able to promote endogenous HA synthesis and alleviate symptoms caused by HA loss, thus introducing potential preventative or therapeutic applications of HA and probiotics. Here, we review the oral absorption, metabolism, and biological function of HA as well as the potential role of probiotics and HA in increasing the efficacy of HA supplements.

Precise Design of Alginate Hydrogels Crosslinked with Microgels for Diabetic Wound Healing.

Alginate hydrogel has received great attention in diabetic wound healing. However, the limited tunability of the ionic crosslinking method prevents the delicate management of physical properties in response to diverse wound conditions. We addressed this issue by using a microgel particle (fabricated by zinc ions and coordinated through the complex of carboxymethyl chitosan and aldehyde hyaluronic acid) as a novel crosslinker. Then the cation was introduced as a second crosslinker to create a double crosslinked network. The method leads to the precise regulation of the hydrogel characters, including the biodegradation rate and the controlled release rate of the drug. As a result, the optimized hydrogels facilitated the live-cell infiltration in vitro and boosted the tissue regeneration of diabetic wounds in vivo. The results indicated that the addition of the microgel as a new crosslinker created flexibility during the construction of the alginate hydrogel, adapting for diverse applications during diabetic-induced wound therapy.

Absolute film separation of dyes/salts and emulsions with a superhigh water permeance through graded nanofluidic channels.

The development of multifunctional films with a high permeability has been of great concern for effective separation of complex aqueous contaminants, especially in the face of zero or near-zero release regulations. Inspired by the natural structure of sandy soils, polydopamine-wrapped/connected polypyrrole sub-micron spheres (PPSM) were closely packed onto a polypyrrole-coated bacterial cellulose (PBC) support, by which a new two-layered PBC/PPSM composite film formed with graded nanofluidic channels. Interestingly, after being soaked in complex water environments of ethanol, acids, bases, heat, cold and high salinity, or else bended/folded for more than 10 times, the structure and performance of this film still stayed the same, validating its high structural stability and flexibility. Even in a high salinity environment over seawater, this PBC/PPSM film exhibits a dye-separation capacity of almost 100% with a surprisingly superhigh water permeance over one thousand L h-1 m-2 bar-1, one or two magnitudes higher than that of the related films reported in the literature. Meanwhile, the ability for effective oil-water-separation was also validated. Besides the superhydrophilicity and underwater superoleophobicity, the synapse-like-structure-induced graded nanofluidic channels are also proposed to play a key role for rendering such an outstandingly comprehensive performance of the film by greatly overcoming fluid resistance and reducing permeation viscosity.

High Titer of (S)-Equol Synthesis from Daidzein in Escherichia coli.

(S)-Equol is the terminal metabolite of daidzein and plays important roles in human health. However, due to anaerobic inefficiency, limited productivity in (S)-equol-producing strains often hinders (S)-equol mass production. Here, a multi-enzyme cascade system was designed to generate a higher (S)-equol titer. First, full reversibility of the (S)-equol synthesis pathway was found and a blocking reverse conversion strategy was established. As biosynthetic genes are present in the microbial genome, an effective daidzein reductase was chosen using evolutionary principles. And our analyses showed that NADPH was crucial for the pathway. In response to this, a novel NADPH pool was redesigned after analyzing a cofactor metabolism model. By adjusting synthesis pathway genes at the right expression level, the entire synthesis pathway can take place smoothly. Thus, the cascade system was optimized by regulating the gene expression intensity. Finally, after optimizing fermentation conditions, a 5 L bioreactor was used to generate a high (S)-equol production titer (3418.5 mg/L), with a conversion rate of approximately 85.9%. This study shows a feasible green process route for the production of (S)-equol.

Enzymatic Production of Chondroitin Oligosaccharides and Its Sulfate Derivatives.

Chondroitin sulfate (CS) has a wide range of physiological functions and clinical applications. However, the biosynthesis of chondroitin oligosaccharides (o-CHs) and sulfate derivatives with specific length is always challenging. Herein, we report enzymatic strategies for producing homogeneous o-CHs and its sulfate derivatives from microbial sourced chondroitin. Chondroitin disaccharides, tetrasaccharides, hexasaccharides, octasaccharides, and decasaccharides with defined structure were produced by controllably depolymerizing microbial sourced chondroitin with an engineered chondroitinase ABC I. The highest conversion rates of the above corresponding o-CHs were 65.5%, 32.1%, 12.7%, 7.2%, and 16.3%, respectively. A new efficient enzymatic sulfation system that directly initiates from adenosine 5'-triphosphate (ATP) and sulfate was developed and improved the sulfation of chondroitin from 8.3% to 85.8% by optimizing the temperature, sulfate and ATP concentration. o-CHs decasaccharide, octasaccharide, hexasaccharide, tetrasaccharide and disaccharide were modified and the corresponding sulfate derivatives with one sulfate group were prepared. The enzymatic approaches constructed here for preparing o-CHs and its sulfate derivatives pave the way for the study of structure-activity relationship and applications.

Systematic Engineering of Escherichia coli for Efficient Production of Nicotinamide Mononucleotide From Nicotinamide.

Research studies on NAD+ have proven its crucial role in aging and disease. Nicotinamide mononucleotide (NMN), as the key intermediate of NAD+, plays a significant role in supplying and maintaining NAD+ levels. In the present study, a biocatalytic method for the efficient synthesis of NMN was established. First, Escherichia coli was systematically modified to make it more conducive to the biosynthesis and accumulation of NMN. Next, the performance of nicotinamide phosphoribosyltransferase from Vibrio bacteriophage KVP40 (VpNadV) was determined, which has the best catalytic activity to produce NMN from nicotinamide. The accumulation of extracellular NMN was further increased after the introduction of an NMN transporter. Fine-tuning of gene expression and copy number led to the synthesis of NMN at the yield of 2.6 g/L at the shake flask level. The introduction of a nicotinamide transporter, BcniaP, could not obviously increase the production of NMN at the shake flask level, but it decreased the production of NMN at the bioreactor level. Finally, the titer of NMN reached 16.2 g/L with a conversion ratio of 97.0% from nicotinamide, both of which are highest according to currently available reports. The fed-batch fermentation with direct supplementation of nicotinamide could facilitate the industrial-scale production of NMN compared to that achieved by the whole-cell catalysis process. These results also represent the highest reported yield of NMN synthesized from nicotinamide in E. coli.

Ameliorative effect of scutellarin on acute alcohol brain injury in mice.

Drinking culture has high significance in both China and the world, whether in the entertainment sector or in social occasions; according to the World Health Organization's 2018 Global Alcohol and Health Report, about 3 million people died from excessive drinking in 2016, accounting for 5.3% of the total global deaths that year. Oxidative stress and inflammation are the most common pathological phenomena caused by alcohol abuse (Snyder et al., 2017). Scutellarin, a kind of flavonoid, is one of the main active ingredients extracted from breviscapine. It exerts anti-inflammatory, antioxidant, and vasodilation effects, and has been used to treat cardiovascular diseases and alcoholic liver injury. Although scutellarin can effectively alleviate multi-target organ injury induced by different forms of stimulation, its protective effect on alcoholic brain injury has not been well-defined. Therefore, the present study established an acute alcohol mice brain injury model to explore the effect of scutellarin on acute alcoholic brain injury. The study was carried out based on the targets of oxidative stress and inflammation, which is of great significance for the targeted therapy of clinical alcohol diseases.

Free-standing hybrid film for separation of dye pollutant with self-cleaning ability under visible light.

The development of low cost and environmental-friendly materials has long been an ambition for effective removal of dye pollutants in complex water environments. In this study, a free-standing separation film of bacterial cellulose reinforced/functionalized by graphitic phase carbon nitride is developed by a facile suction filtration strategy, of which the former is precoated by polypyrrole, and the latter is pre-doped by oxygen to endow the as-obtained film an enhanced photocatalytic performance and self-cleaning ability. The as-obtained film exhibits a high tensile stress of 51.8 ± 1.1 MPa, and a high resistance to cold, heat, acid and alkali. For typical dyes of methylene blue and rhodamine B, a high dye rejection rate of 99.9% at 138 L/m2•h•bar feed flux is obtained by the as-obtained film. Even at a salt concentration higher than 5%, it still maintained high dye removal rates and achieves effective separation of dye and salt. Simultaneously, a high dye photocatalytic degradation of the composite films rates up to 98% in only 90 min, and a high self-cleaning ability demonstrated by recovery of flux after light treatment in cyclic tests. The density functional theory calculation validates the beneficial effects of improved light response range and separated photogenerated electron/holes for the effective degradation of dyes by oxygen-doped carbon nitride coupled with one-dimensional polypyrrole chains. Overall, this study proposes a new direction for the separation of dye pollutants with a high visible-light self-cleaning capacity by structural tailoring of bacterial cellulose with carbon nitride.

Rapid On-Site Detection Method for White Spot Syndrome Virus Using Recombinase Polymerase Amplification Combined With Lateral Flow Test Strip Technology.

The white spot syndrome virus is the most destructive virus threatening the shrimp industry worldwide, causing hundreds of millions of dollars in economic losses each year. There is currently no specific medicine to treat it. Therefore, rapid and accurate detection of WSSV is of great significance for controlling its spread and reducing economic losses. Traditional detection methods, such as polymerase chain reaction (PCR) and quantitative fluorescent PCR, rely on laboratory equipment and are not suitable for field testing. In this study, recombinase polymerase amplification (RPA) combined with a lateral flow strip (LFS) was developed. This method targets the entire genome and designs primers and probes accordingly. The detection can be completed in 30 min at 37°C, and the detection limit of each reaction is 20 copies, which is much more sensitive than other detection methods. The RPA-LFS method is highly specific to the white spot syndrome virus and has no cross-reactivity with other common shrimp viruses or pathogens. In total, 100 field samples were tested and compared to the real-time PCR method. Both methods detected 8 positive results, and the positive detection rate was 100%. The method was fast, simple, specific, and sensitive. It does not rely on laboratory equipment and has broad application prospects for in-field detection, especially in remote areas with underdeveloped medical equipment.

Immune Protective Evaluation Elicited by DNA Vaccination With Neospora caninum Dense Granules Proteins in Mice.

Neospora caninum, an obligate intracellular protozoan, is the major cause for neosporosis and brings serious economic losses to cattle breeding industries worldwide. After invasion, dense granules proteins are abundantly secreted and being important components of parasitophorous vacuole and intravacuolar network where N. caninum survives and replicates. The aim of the present study was to evaluate the protective immunity induced by DNA vaccines with genes encoding dense granules proteins 1 (GRA1), GRA4, GRA9, GRA14, GRA17, and GRA23 against N. caninum tachyzoites in BALB/C mice. Eukaryotic expressing plasmids of pcNcGRAs were constructed and the mice were intramuscularly immunized with pcNcGRAs followed by challenging infection with lethal doses of N. caninum. Immune responses were evaluated through monitoring the levels of serum antibodies, measurement of lymphocyte proliferation, and secretion of cytokines. Immune protection assays were carried out through monitoring survival time, body weight, and parasite burden in the brains. Results showed that all the pcNcGRA DNA vaccines could trigger remarkably specific humoral and cellular responses, with higher levels of IgG and IgG2a antibodies as well as obviously increased secretion of Th1-type IFN-γ cytokines. The immune protective efficacy revealed that pcNcGRA4, pcNcGRA14, and pcNcGRA17 DNA vaccines could individually increase the survival rate to 50, 37.5, and 25% in comparison with 0% in the control group; prolong the survival time more than 20.88 ± 11.12, 18.88 ± 10.83, and 16.63 ± 10.66 days compared with the control group of 4 ± 1.31 days; and decrease parasite burden in the brains to 297.63 ± 83.77, 471.5 ± 110.74, and 592.13 ± 102.2 parasites/100 ng comparing with 1221.36 ± 269.59 parasites/100 ng in the control group. These findings indicated that NcGRA4, NcGRA14, and NcGRA17 are potential vaccine candidates; NcGRA4 displayed better performance in immune protective efficacy and could be further combined with other advantageous antigens applied to the development of safe and effective DNA vaccines against N. caninum.