Rice stripe mosaic virus hijacks rice heading-related gene to promote the overwintering of its insect vector.

Rice stripe mosaic virus (RSMV) is an emerging pathogen which significantly reduces rice yields in the southern region of China. It is transmitted by the leafhopper Recilia dorsalis, which overwinters in rice fields. Our field investigations revealed that RSMV infection causes delayed rice heading, resulting in a large number of green diseased plants remaining in winter rice fields. This creates a favorable environment for leafhoppers and viruses to overwinter, potentially contributing to the rapid spread and epidemic of the disease. Next, we explored the mechanism by which RSMV manipulates the developmental processes of the rice plant. A rice heading-related E3 ubiquitin ligase, Heading date Associated Factor 1 (HAF1), was found to be hijacked by the RSMV-encoded P6. The impairment of HAF1 function affects the ubiquitination and degradation of downstream proteins, HEADING DATE 1 and EARLY FLOWERING3, leading to a delay in rice heading. Our results provide new insights into the development regulation-based molecular interactions between virus and plant, and highlights the importance of understanding virus-vector-plant tripartite interactions for effective disease management strategies.

Gallnut tannic acid alleviates gut damage induced by Salmonella pullorum in broilers by enhancing barrier function and modulating microbiota.

Pullorum disease (PD) is a bacterial infection caused by Salmonella pullorum (S. pullorum) that affects poultry. It is highly infectious and often fatal. Antibiotics are currently the mainstay of prophylactic and therapeutic treatments for PD, but their use can lead to the development of resistance in pathogenic bacteria and disruption of the host's intestinal flora. We added neomycin sulfate and different doses of tannic acid (TA) to the drinking water of chicks at 3 days of age and infected them with PD by intraperitoneal injection of S. pullorum at 9 days of age. We analyzed intestinal histopathological changes and the expression of immune-related genes and proteins by using the plate smear method, histological staining, real-time fluorescence quantitative PCR, ELISA kits, and 16S rRNA Analysis of intestinal flora. The results demonstrate that S. pullorum induces alterations in the immune status and impairs the functionality of the liver and intestinal barrier. We found that tannic acid significantly ameliorated S. pullorum-induced liver and intestinal damage, protected the intestinal physical and chemical barriers, restored the intestinal immune barrier function, and regulated the intestinal flora. Our results showed that TA has good anti-diarrhoeal, growth-promoting, immune-regulating, intestinal barrier-protecting and intestinal flora-balancing effects, and the best effect was achieved at an additive dose of 0.2%.

Guiding antibiotics towards their target using bacteriophage proteins.

Novel therapeutic strategies against difficult-to-treat bacterial infections are desperately needed, and the faster and cheaper way to get them might be by repurposing existing antibiotics. Nanodelivery systems enhance the efficacy of antibiotics by guiding them to their targets, increasing the local concentration at the site of infection. While recently described nanodelivery systems are promising, they are generally not easy to adapt to different targets, and lack biocompatibility or specificity. Here, nanodelivery systems are created that source their targeting proteins from bacteriophages. Bacteriophage receptor-binding proteins and cell-wall binding domains are conjugated to nanoparticles, for the targeted delivery of rifampicin, imipenem, and ampicillin against bacterial pathogens. They show excellent specificity against their targets, and accumulate at the site of infection to deliver their antibiotic payload. Moreover, the nanodelivery systems suppress pathogen infections more effectively than 16 to 32-fold higher doses of free antibiotics. This study demonstrates that bacteriophage sourced targeting proteins are promising candidates to guide nanodelivery systems. Their specificity, availability, and biocompatibility make them great options to guide the antibiotic nanodelivery systems that are desperately needed to combat difficult-to-treat infections.

A Standardized Rat Model to Study Peri-implantitis of Transmucosal Osseointegrated Implants.

With the high incidence rate, distinctive implant characteristic and unique infection pattern, peri-implantitis (PI) requires a specially designed implant animal model for the researches on the pathogenesis and treatments. Previous small-animal PI models exhibit variability in implant site selection, design, and surgical procedures resulting in unnecessary tissue damage and less effectivity. Herein, a quantitative-analysis-based standardized rat model for transmucosal PI-related research was proposed. After dissecting the anatomic structures of the rat maxilla, we determined that placing the implant anterior to the molars in the rat maxilla streamlined the experimental period and enhanced animal welfare. We standardized the model by controlling the rat strain, gender, and size. The customized implant and a series of matched surgical instruments were appropriately designed. A clear, step-by-step surgical process was established. These designs ensured the success rate, stability, and replicability of the model. Each validation method confirmed the successful construction of the model. This study proposed a quantitative-analysis-based standardized transmucosal PI rat model with improved animal welfare and reliable procedures. This model could provide efficient in vivo insights to study the pathogenesis and treatments of PI and preliminary screening data for further large-animal and clinical trials.

Immobilization of pancreatin based on ultrasound-assisted polydopamine functionalized magnetic porous chitosan for the detoxification of ochratoxin A in wine.

Ochratoxin A (OTA) is a mycotoxin that globally contaminates fruits and their products. Since OTA have a huge negative impact on health hazards and economic losses, it is imperative to establish an effective and safe strategy for detoxification. Here, pancreatin was immobilized on the surface of polydopamine functionalized magnetic porous chitosan (MPCTS@ PDA) for the degradation of OTA. Compared with free pancreatin, MPCTS@ PDA@ pancreatin displayed excellent thermal stability, acid resistance, storage stability and OTA detoxification in wine (>58%). Moreover, the MPCTS@ PDA@ pancreatin retained 43% initial activity after 8 reuse cycles. There was no significant change in the quality of wine after MPCTS@ PDA@ pancreatin treatment. Moreover, it did not exhibit cytotoxicity which facilitated its application in wine. These results demonstrated that MPCTS@ PDA@ pancreatin can be used as a highly effective biocatalysate for OTA detoxification in wine.

[Regulation of electroacupuncture on non-canonical pathway of hepatocellular pyroptosis in rats with nonalcoholic fatty liver disease].

OBJECTIVE: To observe the effect and mechanism of electroacupuncture (EA) on non-canonical pathway of hepatocellular pyroptosis in nonalcoholic fatty liver disease (NAFLD). METHODS: Sixty male SD rats were randomly divided into a normal diet group (n=15) and a high fat modeling group (n=45). The rats in the high fat modeling group were fed with customized high fat diet for 8 weeks to establish NAFLD model. Thirty successfully modeled rats were selected and randomly divided into a model group (n=10), an EA group (n=10) and a non-acupoint with shallow needling group (n=10), and 10 rats were randomly selected from the normal diet group as the control group additionally. In the EA group, EA was applied at bilateral "Fenglong" (ST 40) and "Ganshu" (BL 18), with disperse-dense wave, in frequency of 4 Hz/20 Hz and in intensity of 3 mA. In the non-acupoint with shallow needling group, shallow needling was delivered at points 5 mm from bilateral "Fenglong" (ST 40) and "Ganshu" (BL 18), the EA stimulation parameters were same as the EA group. The intervention was given once a day, 20 min a time, 5 days a week for 4 weeks in the two groups. After intervention, the liver morphology was observed by oil red "O" staining, the serum levels of lipopolysaccharide (LPS), interleukin (IL)-1ß, IL-18 and tumor necrosis factor-α (TNF-α) were detected by ELISA, the protein expression of gasdermin D (GSDMD), GSDMD-N, cysteine aspartic acid specific protease-11 (Caspase-11), IL-1ß, IL-18 and TNF-α in liver tissue were detected by Western blot, the mRNA expression of GSDMD, Caspase-11, IL-1ß, IL-18 and TNF-α in liver tissue was detected by real-time PCR in rats of each group. RESULTS: In the model group, vacuoles in different size were found in the hepatocellular cytoplasm, and the fat droplets were in schistose accumulation. Compared with the model group, the hepatocellular fat droplets and the degree of hepatic steatosis were reduced in the EA group and the non-acupoint with shallow needling group. Compared with the control group, the serum levels of LPS, IL-1ß, IL-18 and TNF-α were increased (P<0.01), the protein and mRNA expression of GSDMD, Caspase-11, IL-1ß, IL-18, TNF-α as well as the protein expression of GSDMD-N in the liver tissue were increased (P<0.01) in the model group. Compared with the model group, the serum levels of LPS, IL-1ß, IL-18 and TNF-α were decreased (P<0.01), the protein and mRNA expression of GSDMD, IL-1ß, IL-18 and TNF-α in the liver tissue were decreased (P<0.01), the protein expression of GSDMD-N and the mRNA expression of Caspase-11 in the liver tissue were decreased (P<0.01) in the EA group and the non-acupoint with shallow needling group. Compared with the model group, the protein expression of Caspase-11 in the liver tissue was decreased (P<0.01) in the EA group. Compared with the non-acupoint with shallow needling group, the serum levels of LPS, IL-1ß, IL-18 and TNF-α were decreased (P<0.01), the protein and mRNA expression of GSDMD, Caspase-11, IL-1ß and IL-18 in the liver tissue were decreased (P<0.01), the protein expression of GSDMD-N and the mRNA expression of TNF-α in the liver tissue were decreased (P<0.01) in the EA group. CONCLUSION: EA can inhibit hepatocellular pyroptosis in NAFLD rats, and its mechanism may be related to reducing the serum level of LPS, and down-regulating the expression of the non-canonical pathway related factors i.e. GSDMD, GSDMD-N, Caspase-11, IL-1ß, IL-18 and TNF-α.

Effects of electroacupuncture of different intensities and durations on PERK/ATF4/CHOP signaling pathway in liver of non-alcoholic fatty liver disease rats. / ä¸åŒå¼ºåº¦åŠæ—¶ç¨‹ç”µé’ˆå¹²é¢„å¯¹éžé ’ç²¾æ€§è„‚è‚ªè‚ç— å¤§é¼ è‚è„PERK/ATF4/CHOP通路的影响.

OBJECTIVES: To analyze the effects of electroacupuncture (EA) at "Fenglong" (ST40) and "Zusanli" (ST36) of different intensities and durations on rats with non-alcoholic fatty liver disease (NAFLD) based on the protein kinase R-like endoplasmic reticulum kinase (PERK)-activating transcription factor 4 (ATF4)-C/EBP homologous protein (CHOP) signaling pathway, so as to explore its mechanism underlying improvement of NAFLD. METHODS: SD rats were randomly divided into normal diet group, high-fat model group, sham EA group, strong stimulation EA (SEA) group, and weak stimulation EA (WEA) group, with 15 rats in each group. Each group was further divided into 2, 3, and 4-week subgroups. NAFLD rat model was established by feeding a high-fat diet. After successful modeling, rats in the SEA and WEA groups received EA at bilateral ST40 and ST36 with dense and sparse waves (4 Hz/20 Hz) at current intensities of 4 mA (SEA group) and 2 mA (WEA group), lasting for 20 minutes, once a day, 5 days a week with 2 days of rest. The sham EA group only had the EA apparatus connected without electricity. Different duration subgroups were intervened for 2, 3, and 4 weeks. After the intervention, the contents of serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) in rats were detected by an automatic biochemical analyzer；liver morphological changes were observed by Oil Red O staining；real-time fluorescence quantitative PCR and Western blot were used to detect the expression of PERK, ATF4, and CHOP mRNAs and proteins in the rat liver tissue. RESULTS: In the high-fat model group, there was a significant accumulation of red lipid droplets in the liver cells, which was reduced significantly in the SEA group at the 4th week. Compared with the normal diet group with the same treatment duration, the contents of serum ALT, AST, and the expression of PERK, ATF4, and CHOP mRNAs and proteins in the liver tissue were elevated (P<0.01) in the high-fat model group . Compared with the high-fat model group with the same treatment duration, the contents of serum ALT, AST, and the expression of PERK, ATF4, CHOP mRNAs and proteins in the liver tissue were decreased (P<0.01, P<0.05) in the SEA and WEA groups. Compared with the sham EA group with the same treatment duration, the contents of serum ALT, AST, and the expression of PERK, ATF4, and CHOP mRNAs were decreased (P<0.01, P<0.05) in the SEA and WEA groups, the expression of PERK, ATF4, and CHOP proteins in the liver tissue was decreased (P<0.01) in the SEA group at the 2nd, 3rd, and 4th week, the expression of PERK and CHOP proteins at the 2nd, 3rd, 4th week and ATF4 protein at 2nd week in the liver tissue were decreased (P<0.01, P<0.05) in the WEA group. Compared with the SEA group with the same treatment duration, the contents of serum ALT, AST, and the expression of PERK, ATF4, and CHOP mRNAs and proteins in the liver tissue were elevated (P<0.05, P<0.01) in the WEA group. Compared with the 2-week time point within the groups, the contents of serum ALT, AST, and the expression of PERK, ATF4, and CHOP mRNAs and PERK proteins in the liver tissue were decreased (P<0.01, P<0.05) in the SEA and WEA groups at 3rd and 4th week, the expression of ATF4 proteins in the liver tissue was decreased (P<0.01) in the SEA group at 3rd and 4th week, and the expression of CHOP proteins in the liver tissue was decreased (P<0.01) in the SEA group at 4th week and in the WEA group at 3rd and 4th week. Compared with the 3-week time point within the groups, the contents of serum ALT, AST, and the expression of PERK, ATF4, and CHOP mRNAs were significantly decreased (P<0.05, P<0.01) in the SEA and WEA groups at 4th week, the expression of PERK and CHOP proteins in the liver tissue was decreased (P<0.01) in the SEA and WEA groups at 4th week, and the expression of ATF4 protein in the liver tissue was decreased (P<0.05) in the SEA group at 4th week. CONCLUSIONS: EA at ST40 and ST36 can significantly improve liver function in NAFLD rats, and its mechanism of action may involve inhibiting PERK expression thereby targeting the downstream ATF4/CHOP signaling pathway to suppress endoplasmic reticulum stress, exerting a liver protective effect；the optimal effect was observed with EA intensity of 4 mA for 4 weeks.

A perovskite-based electrochemiluminescence aptasensor for tetracycline screening.

Tetracyclines are currently the most commonly used class of antibiotics, and their residue issue significantly impacts public health safety. In this study, a surface modification of perovskite with cetyltrimethylammonium bromide led to the generation of stable electrochemiluminescence (ECL) emitters in aqueous systems and improved the biocompatibility of perovskite. A perovskite quantum dot-based ECL sensing strategy was developed. Utilizing the corresponding aptamer of the antibiotics, strain displacement reactions were triggered, disrupting the ECL quenching system composed of perovskite and Ag nanoclusters (Ag NCs) on the electrode surface, generating a signal to achieve quantitative detection of several common tetracycline antibiotics. The perovskite quantum dot provided a strong and stable initial signal, while the efficient catalytic activity of the silver cluster enhanced the recognition sensitivity. Tetracycline, chlortetracycline, and oxytetracycline were used as examples to demonstrate the differentiation and quantitative detection through this method. In addition, the aptasensor exhibited analytical performance with the linear range (0.1-10 µM OTC) and good recovery rates of 94.7% to 101.6% in real samples. This approach has the potential to become a sensitive and practical approach for assessing antibiotic residues.

Dendrobium officinale Polysaccharide (DOP) inhibits cell hyperproliferation, inflammation and oxidative stress to improve keratinocyte psoriasis-like state.

PURPOSE: Psoriasis is a skin disease characterized by excessive proliferation, inflammation and oxidative stress in keratinocytes. The present study aimed to investigate the therapeutic effects of Dendrobium officinale polysaccharide (DOP) on keratinocyte psoriasis-like models. METHODS: The HaCaT keratinocyte inflammation models were induced by interleukin (IL)-22 or lipopolysaccharide (LPS), respectively, and oxidative stress damage within cells was elicited by H2O2 and treated using DOP. CCK-8 and EdU were carried out to detect cell proliferation. ELISA, qRT-PCR, and Western blot were conducted to measure the expression of pro-inflammatory cytokines IL17A, IL-23, IL1ß, tumor necrosis factor alpha (TNF-α), and IL-6. Reactive oxygen species (ROS) level in keratinocytes was detected by flow cytometry. Cell proliferation-associated proteins (PCNA, Ki67, Cyclin D1) and pathway proteins (p-AKT and AKT), and oxidative stress marker proteins (Nrf-2, CAT, SOD1) were detected by Western blot. RESULT: DOP did not affect the proliferation of normal keratinocytes, but DOP was able to inhibit the proliferative activity of IL-22-induced overproliferating keratinocytes and suppress the expression of proliferation-related factors PCNA, Ki67, and Cyclin D1 as well as the proliferation pathway p-AKT. In addition, DOP treatment was able to inhibit IL-22 and LPS-induced inflammation and H2O2-induced oxidative stress, including the expression of IL17A, IL-23, IL1ß, TNF-α, IL-6, and IL1ß, as well as the expression levels of intracellular ROS levels and cellular oxidative stress-related indicators SOD, MDA, CAT, Nrf-2 and SOD1. CONCLUSION: DOP inhibits keratinocyte hyperproliferation, inflammation and oxidative stress to improve the keratinocyte psoriasis-like state.

Surgical performance of dental students using computer-assisted dynamic navigation and freehand approaches.

INTRODUCTION: Nowadays, the training of implant placement has shifted from once entirely instructor-student teaching to the increasing use of computer-assisted simulation. Based on computerized virtual planning, dynamic navigation has been used for implant placement with higher accuracy than the traditional freehand protocol. However, whether dynamic navigation benefits to the training of dental students in implant placement remains controversial. This study aimed to compare the surgical performance of dental students in implant placement using computer-assisted dynamic navigation and freehand approaches. MATERIALS AND METHODS: A total of 20 dental students (6 males, 14 females, age: 25.6 ± 0.5 years) were enrolled in this study. With the traditional freehand approach (training 1) as the control protocol, computer-assisted dynamic navigation (training 2) was used in the training of dental students in implant placement. For each training, both the operating time (OT) of students and placement accuracy represented by the linear (at the implant platform, Dpl, and apex, Dap) and angular (Dan) deviations between the virtually planned and placed implants were recorded. Statistical comparisons were made between the two training protocols as well as male and female surgeons. RESULTS: OT2 was around twice of OT1 (p < .0001), whereas Dan1 was almost three times of Dan2 (p < .0001). Dap1 and Dpl1 were significantly higher than Dap2 (p = .014) and Dpl2 (p = .033) respectively. Besides, male students showed statistically higher Dpl1 (p = .033) and Dan1 (p = .002) than females. No significant difference was found between male and female students in OT1, OT2, Dpl2, Dap1, Dap2 and Dan2. CONCLUSIONS: Within the limitations of this study, the use of computer-assisted dynamic navigation in the preclinical training could improve the surgical performance of the dental students in implant placement. The combination of dynamic navigation with the traditional preclinical surgical training may benefit to dental students and could be applied in dental education.

Balance between the CMC/ACP Nanocomplex and Blood Assimilation Orchestrates Immunomodulation of the Biomineralized Collagen Matrix.

Calcium phosphate-based biomineralized biomaterials have broad application prospects. However, the immune response and foreign body reactions elicited by biomineralized materials have drawn substantial attention recently, contrary to the immune microenvironment optimization concept. Therefore, it is important to clarify the immunomodulation properties of biomineralized materials. Herein, we prepared the biomineralized collagen matrix (BCM) and screened the key immunomodulation factor carboxymethyl chitosan/amorphous calcium phosphate (CMC/ACP) nanocomplex. The immunomodulation effect of the BCM was investigated in vitro and in vivo. The BCM triggered evident inflammatory responses and cascade foreign body reactions by releasing the CMC/ACP nanocomplex, which activated the potential TLR4-MAPK/NF-κB pathway, compromising the collagen matrix biocompatibility. By contrast, blocking the CMC/ACP nanocomplex release via the blood assimilation process of the BCM mitigated the inflammation and foreign body reactions, enhancing biocompatibility. Hence, the immunomodulation of the BCM was orchestrated by the balance between the CMC/ACP nanocomplex and the blood assimilation process. Controlling the release of the CMC/ACP nanocomplex to accord the biological effects of ACP with the temporal regenerative demands is key to developing advanced biomineralized materials.

Characteristics of herbaceous plant community composition, niche and stability under different main-tenance measures at Sanxingdui City Wall, Sichuan, China.

To understand the distribution characteristics and restoration status of vegetation at Sanxingdui City Wall, we sampled five typical communities of the city wall at the Sanxingdui site and explored the stability and niche characteristics of herbaceous plant communities under different maintenance measures (natural regeneration, planting, abandoned field, shrub removal, and pruning) following the niche theory and the improved contribution law method. A total of 87 herbaceous species belonging to 73 genera and 31 families were recorded. Compositae and Gramineae were dominant, and perennial herbs were the majority. There were differences in the niche breadth of major herbaceous species under different maintenance measures. The niche breadth of annual plants was higher under natural regeneration and shrub removal, and that of perennial plants was higher under planting, abandoned field, and pruning measures. The niche overlap and similarity of herbaceous plants were higher under natural regene-ration, shrub removal and pruning measures, and were the lowest under planting measure. The importance values were positively correlated with the niche breadth, but the ranking was not completely consistent. Species with higher niche breadth usually had higher probability of niche overlap and higher niche similarity. Combined with the M-Godron's stability analysis, community stability was comparable among shrub removal, pruning, and natural regeneration measures whereas the abandoned field and planting showed lower community stability. We recommended the implementation of in situ conservation measures based on natural regeneration, supplemented by scientific artificial maintenance (shrub removal, pruning, etc.) when necessary, so as to achieve a stable species composition and promote the sustainable development and vegetation landscape restoration at Sanxingdui City Wall.

Optimized osteogenesis of porcine bone-derived xenograft through surface coating of magnesium-doped nanohydroxyapatite.

As one of the key factors influencing the outcome of guided bone regeneration, the currently used xenografts possess insufficient capability in osteogenesis. With the aim of improving the osteogenic performance of xenografts, porcine bone-derived hydroxyapatite (PHA) was prepared and subsequently coated by magnesium-doped nano hydroxyapatite (nMgHA, 10%, 20%, and 30% of Mg/Ca + Mg) through a straightforward and cost-efficient approach. The physiochemical and biological properties of nMgHA/PHAs were examinedin vitroandin vivo. The inherent three-dimensional (3D) porous framework with the average pore size of 300 µm was well preserved in nMgHA/PHAs. Meanwhile, excess magnesium released from the so-called 'surface pool' of PHA was verified. In contrast, slower release of magnesium at lower concentrations was detected for nMgHA/PHAs. Significantly more newly-formed bone and microvessels were observed in 20%nMgHA/PHA than the other specimens. With the limitations of the present study, it could be concluded that PHA coated by 20%nMgHA may have the optimized osteogenic performance due to the elimination of the excess magnesium from the 'surface pool', the preservation of the inherent 3D porous framework with the favorable pore size, and the release of magnesium at an appropriate concentration that possessed osteoimmunomodulatory effects on macrophages.

An extracellular electron transfer enhanced electrochemiluminescence aptasensor for Escherichia coli analysis.

As a crucial indicator in food and water safety testing, the detection of Escherichia coli plays a significant role in maintaining environmental sanitation and promoting public health. Herein, based on the electrochemical activity characteristics of E. coli, we established an enhanced electrochemiluminescence aptasensor for E. coli analysis. This study presents a new method for accurate identification by utilizing a double aptamer recognition system. Specifically, a nano-cadmium sulfide (CdS) modified aptamer was used for primary labeling, while a second aptamer was immobilized on a graphene/chitosan composite electrode for re-capture. The use of two aptamers improves the accuracy of the identification process. Furthermore, the application of an electrode potential facilitates continuous electron transfer between the electrode and electrochemically active microorganisms, resulting in an enhanced electroluminescence signal in relation to the metabolic status. This strategy possesses better sensitivity, accuracy, and stability, demonstrating its potential for E. coli analysis.

Cracking the code: Deciphering the role of the tumor microenvironment in osteosarcoma metastasis.

Osteosarcoma (OS) is the most common malignant bone tumor in children and adolescents. It is characterized by a rapid progression, poor prognosis, and early pulmonary metastasis. Over the past 30 years, approximately 85% of patients with osteosarcoma have experienced metastasis. The five-year survival of patients with lung metastasis during the early stages of treatment is less than 20%. The tumor microenvironment (TME) not only provides conditions for tumor cell growth but also releases a variety of substances that can promote the metastasis of tumor cells to other tissues and organs. Currently, there is limited research on the role of the TME in osteosarcoma metastasis. Therefore, to explore methods for regulating osteosarcoma metastasis, further investigations must be conducted from the perspective of the TME. This will help to identify new potential biomarkers for predicting osteosarcoma metastasis and assist in the discovery of new drugs that target regulatory mechanisms for clinical diagnosis and treatment. This paper reviews the research progress on the mechanism of osteosarcoma metastasis based on TME theory, which will provide guidance for the clinical treatment of osteosarcoma.

Elucidating the Mechanism of Action of the Gram-Negative-Pathogen-Selective Cyclic Antimicrobial Lipopeptide Brevicidine.

Due to the accelerated appearance of antimicrobial-resistant (AMR) pathogens in clinical infections, new first-in-class antibiotics, operating via novel modes of action, are desperately needed. Brevicidine, a bacterial nonribosomally produced cyclic lipopeptide, has shown potent and selective antimicrobial activity against Gram-negative pathogens. However, before our investigations, little was known about how brevicidine exerts its potent bactericidal effect against Gram-negative pathogens. In this study, we find that brevicidine has potent antimicrobial activity against AMR Enterobacteriaceae pathogens, with MIC values ranging between 0.5 µM (0.8 mg/L) and 2 µM (3.0 mg/L). In addition, brevicidine showed potent antibiofilm activity against the Enterobacteriaceae pathogens, with the same 100% inhibition and 100% eradication concentration of 4 µM (6.1 mg/L). Further mechanistic studies showed that brevicidine exerts its potent bactericidal activity by interacting with lipopolysaccharide in the outer membrane, targeting phosphatidylglycerol and cardiolipin in the inner membrane, and dissipating the proton motive force of bacteria. This results in metabolic perturbation, including the inhibition of ATP synthesis; the inhibition of the dehydrogenation of NADH; the accumulation of reactive oxygen species in bacteria; and the inhibition of protein synthesis. Finally, brevicidine showed a good therapeutic effect in a mouse peritonitis-sepsis model. Our findings pave the way for further research on the clinical applications of brevicidine to combat prevalent infections caused by AMR Gram-negative pathogens worldwide.

Optimizing the biodegradability and osteogenesis of biogenic collagen membrane via fluoride-modified polymer-induced liquid precursor process.

Biogenic collagen membranes (BCM) have been widely used in guided bone regeneration (GBR) owing to their biodegradability during tissue integration. However, their relatively high degradation rate and lack of pro-osteogenic properties limit their clinical outcomes. It is of great importance to endow BCM with tailored degradation as well as pro-osteogenic properties. In this study, a fluoride-modified polymer-induced liquid precursor (PILP) based biomineralization strategy was used to convert the collagen membrane from an organic phase to an apatite-based inorganic phase, thus achieving enhanced anti-degradation performance as well as osteogenesis. As a result, three phases of collagen membranes were prepared. The original BCM in the organic phase induced the mildest inflammatory response and was mostly degraded after 4 weeks. The organic-inorganic mixture phase of the collagen membrane evoked a prominent inflammatory response owing to the fluoride-containing amorphous calcium phosphate (F-ACP) nanoparticles, resulting in active angiogenesis and fibrous encapsulation, whereas the inorganic phase induced a mild inflammatory response and degraded the least owing to the transition of F-ACP particles into calcium phosphate with high crystallinity. Effective control of ACP is key to building novel apatite-based barrier membranes. The current results may pave the way for the development of advanced apatite-based membranes with enhanced barrier performances.

Super-resolution image reconstruction from sparsity regularization and deep residual-learned priors.

BACKGROUND: Computed tomography (CT) plays an important role in the field of non-destructive testing. However, conventional CT images often have blurred edge and unclear texture, which is not conducive to the follow-up medical diagnosis and industrial testing work. OBJECTIVE: This study aims to generate high-resolution CT images using a new CT super-resolution reconstruction method combining with the sparsity regularization and deep learning prior. METHODS: The new method reconstructs CT images through a reconstruction model incorporating image gradient L0-norm minimization and deep image priors using a plug-and-play super-resolution framework. The deep learning priors are learned from a deep residual network and then plugged into the proposed new framework, and alternating direction method of multipliers is utilized to optimize the iterative solution of the model. RESULTS: The simulation data analysis results show that the new method improves the signal-to-noise ratio (PSNR) by 7% and the modulation transfer function (MTF) curves show that the value of MTF50 increases by 0.02 factors compared with the result of deep plug-and-play super-resolution. Additionally, the real CT image data analysis results show that the new method improves the PSNR by 5.1% and MTF50 by 0.11 factors. CONCLUSION: Both simulation and real data experiments prove that the proposed new CT super-resolution method using deep learning priors can reconstruct CT images with lower noise and better detail recovery. This method is flexible, effective and extensive for low-resolution CT image super-resolution.

A CRISPR/Cas12a-assisted array for Helicobacter pylori DNA analysis in saliva.

Helicobacter pylori infection has become a threat to the world populations. This leads to an urgent need of an efficient and convenient approach to accurately diagnose H. pylori infection. Saliva-based diagnoses are particularly welcomed for their efficiency and convenience. Aiming at saliva sample analysis, we proposed a CRISPR/Cas12a-assisted array, which had integrated H. pylori concentration detection and genotype screening functions. Single-nucleotide variations (SNVs) could be distinguished using the screening array with different probes, and an isothermal cycling strategy was combined with the trans-cleavage activity of Cas12a for signal amplification to improve accuracy of the diagnosis. As a demonstration, the SNV screening array was fabricated by utilizing the hybridization efficiency difference caused by mismatched bases. The array was able to successfully distinguish between ten H. pylori genotypes, and combined with the successful SDA biosensing, it had a LOD of as low as 60 fM. It was also able to diagnose H. pylori infection in saliva samples from infected patients. Together, the developed array has a potential in large-scale clinical screening and is a promising tool for the diagnosis and prevention of H. pylori infection-related diseases.

Effects of ultrasonic treatment on the surface bacteria of Lyophyllum decastes during storage.

This study explores the relationship between the storage quality and bacterial microflora in the mushroom Lyophyllum decastes. The surface bacteria of L. decastes were separated by combining the traditional culture plate separation and 16S rRNA sequencing method, to study the effects of ultrasonic (US) treatment on the surface bacteria of L. decastes during storage. The results demonstrated that Pantoea agglomerans and Pseudomonas fluorescens were among the 15 culturable bacteria isolated with traditional plate method during storage, belonging to 2 phyla and 7 genera. US treatment could inhibit the growth and significantly increase cell membrane permeability, and contents extravasation in P. agglomerans, though its inhibitory effect on P. fluorescens was less. The 16S rRNA sequencing revealed, bacteria from 9 phyla and 35 genera were isolated, and P. fluorescens was the dominant species throughout the storage time. These results indicated that the composition of mushroom surface microflora of Control (CK) and US groups are similar, and the bacterial microflora networks analysis also showed a positive correlation. The KEGG annotation for the functional classification of the bacteria showed that a total of 328 pathways were acquired at the KEGG l3 level, and the relative abundance of membrane transport, amino acid metabolism, carbohydrate metabolism, and energy metabolism pathway was high. Moreover, the relative abundance of the surface bacteria of L. decastes also decreased. Hence, the US treatment had a better bacteriostatic effect, maintained the whiteness index and firmness, and improved the sensory quality of L. decastes during storage.