Ergothioneine (ERG), a sulfur-containing amino acid derivative known for its antioxidant activity, has a wide range of applications in healthcare and nutrition. Escherichia coli has been extensively studied as a platform for ERG production due to its rapid growth and well-established genetic tools. However, most engineered strains rely on plasmid-based expression system, which are genetically unstable. Additionally, the requirement for antibiotics to maintain plasmid stability further limits the feasibility of plasmid-based systems for industrial-scale production. Here, we established a plasmid-free E. coli platform for ERG biosynthesis using a multi-copy chromosomal integration CRISPR-associated transposase (MUCICAT) system. We first integrated a three-gene ERG biosynthetic pathway into the E. coli genome at varying copy numbers, resulting in a five-copy strain (P5) that exhibited the highest ERG titer of 222.5 ± 5.0 mg/L. Subsequently, we reinforced the two key catalytic modules-histidine methylation and SAM biosynthesis-through iterative genomic integration of the corresponding genes, yielding a plasmid-free strain P18 that produced 370.0 ± 7.0 mg/L ERG. The engineered strain P18 exhibited excellent genetic stability, as confirmed by serial passaging. When scaled up in a 5-L bioreactor under fed-batch condition, an ERG titer of 10.1 g/L was achieved. This study demonstrates a plasmid-free ERG production strategy based on stable, multi-copy chromosomal integration of the ERG biosynthetic pathway in E. coli, highlighting its potential as an efficient platform for scalable ERG production.

Glucose deprivation is a major metabolic stress that requires coordinated adaptive responses to maintain cellular homeostasis and survival, yet the role of tripartite motif-containing 24 (TRIM24) in this process remains unclear. To address this question, we generated CRISPR-Cas9-mediated TRIM24-knockout MCF-7 and HEK293 cell lines, performed targeted metabolomic profiling and aspartate assays, used 5-aminoimidazole-4-carboxamide-1-β-D-ribofuranoside (AICAR), aminooxyacetic acid (AOA), aspartate supplementation, and glutamic-oxaloacetic transaminase 2 (GOT2) knockdown to probe AMPK signaling and aspartate metabolism, and examined starvation responses in constitutive Trim24 knockout mice on a C57BL/6 background. Loss of TRIM24 sensitized cells to glucose deprivation. Re-expression of TRIM24 partially restored cell viability under glucose deprivation in both MCF-7 and HEK293 cells. Under glucose-free conditions, TRIM24 deficiency was associated with impaired AMP-activated protein kinase (AMPK) pathway activation, increased intracellular aspartate accumulation, and altered ATP/AMP levels. Pharmacological reactivation of AMPK by AICAR improved the survival of TRIM24-deficient cells under glucose deprivation. Reducing intracellular aspartate by AOA treatment or GOT2 knockdown restored AMPK pathway activation and improved adaptation to glucose deprivation, whereas exogenous aspartate suppressed AMPK signaling and increased ATP/AMP levels. In vivo, starvation of Trim24-deficient mice was associated with reduced AMPK pathway activation and increased aspartate levels. Together, these findings support a model in which TRIM24 contributes to adaptation to glucose deprivation and in which abnormal aspartate accumulation contributes to impaired AMPK pathway activation in TRIM24-deficient cells.

Ergothioneine (ERG) is a natural sulfur-containing compound derived from histidine that is known for its significant antioxidant properties. Microbial biosynthesis of ERG has attracted considerable interest due to its sustainability and scalability. Despite efforts to construct engineered strains, the ERG yield remains low. In this study, Escherichia coli was engineered for high-level ERG production through a series of metabolic engineering strategies. A promising methyltransferase was identified and an evolved variant with 1.4-fold increase in catalytic activity was obtained through random mutagenesis and screening. Subsequently, combinatorial pathway engineering was conducted by combining various sulfoxide synthases and C-S lyases with the evolved methyltransferase, generating a strain with 297 ± 3 mg/L of ERG. To further improve the pathway efficiency, ribosome binding site and promoter engineering were innovatively employed to fine-tune the expression levels of key enzymes in the ERG synthesis pathway. Furthermore, the supply of S-adenosylmethionine, an essential methyl donor, was enhanced by applying cofactor engineering. Finally, a high ERG-producing strain S5 was obtained, whose ERG yield reached 453 ± 9 mg/L. Upon scale-up in a 5-L fermenter, the strain S5 produced 12161 ± 311 mg/L of ERG at 144 h, representing the highest titer achieved to date in microbial fermentation. This work demonstrated that the effectiveness of synergistic application of multiple metabolic engineering strategies in improving product yield, laying a foundation for the cost-effective biosynthesis of ERG.

Polymethylated flavonoids exhibit significant biological activities. Methylation at multiple sites catalyzed by O-methyltransferases (OMTs) enables one-step synthesis of polymethylated flavonoids, thereby facilitating structural modification and druggability research of flavonoids. To identify OMTs with both substrate and regiochemical promiscuity, we performed large-scale phylogenetic and predicted structural analyses of 3873 caffeic acid OMT (COMT) sequences. Functional characterization yielded 16 active COMTs, including a microbial enzyme from Streptomyces cinnamoneus that exhibits broad substrate promiscuity toward flavonoids, hydroxyindoles, anthraquinones, and polyphenols. This biocatalyst methylates up to seven distinct sites on flavonoids with a unique hydrophobic active site favoring adjacent hydroxyl groups on either the A ring or B ring and the C3-hydroxyl group of flavonoids. It enables the one-step synthesis of 42 mono- and polymethylated bioactive derivatives from 22 substrates. This work provides a powerful tool for scaffold diversification in natural product synthesis and applications in food, agriculture, and drug discovery.

S-Adenosyl-l-methionine (SAM) is an essential biological cofactor. However, its application in vitro is hindered by high cost and instability. This study addresses this limitation by developing a biomimetic SAM analogue, S-adenosyl-l-methylcysteine (SAMC), and an efficient enzymatic regeneration system. We established an ATP-independent synthesis of its precursor, S-adenosyl-l-cysteine (SAC), using S-adenosyl-l-homocysteine (SAH) hydrolase. Structural analysis and subsequent directed evolution of thiopurine methyltransferase from Aspergillus clavatus (AclTMT) and halide methyltransferase from Arabidopsis thaliana (AtHMT) yielded positive mutants, notably AclTMT_R43A-T165M and AtHMT_Q49A-V140M, which exhibited dramatically enhanced activity (33.1- and 27.1-fold increases in specific activity, respectively) and catalytic efficiency (35.5- and 12.8-fold higher k cat/K M, respectively) for SAC methylation using artificial donors MeOTs and CH3I, respectively. Crucially, we constructed a one-pot cofactor regeneration cycle coupling these engineered methyltransferases (MTs) with natural product MTs (MT-6 from Streptomyces cinnamoneus and MT-31 from Nostoc sp.). This system successfully synthesized various methylated flavonoids, quinone, and indole with high conversion rates (exceeding 80% in multiple cases) and identical regioselectivity compared to SAM-dependent reactions. Our work demonstrates that SAMC can functionally replace SAM, providing a cost-effective and efficient platform for in vitro methylation biocatalysis and expanding the toolbox for natural product diversification.

Unsaturated fatty acids (UFAs) are essential for the membrane function in most bacteria. In Helicobacter pylori (H. pylori), a gastric pathogen, UFA biosynthesis depends on the bifunctional dehydrogenase/isomerase FabX, a promising target against H. pylori. Herein, we report the first FabX inhibitor, P61G11 (compound 1, IC50 = 3.7 ± 0.2 μM), identified via high-throughput screening and featuring a 1,3,4-thiadiazole sulfonamide scaffold. The costructure of FabX-1 reveals occupancy of the L-shaped substrate-binding tunnel via hydrophobic interactions and hydrogen bonds. Structure-based optimization led to more potent derivatives, among which compound 47 showed potent inhibition (IC50 = 0.128 ± 0.002 μM), representing a 29-fold improvement. Compound 47 also demonstrated strong in vitro antibacterial activity (MIC = 0.5-1 μg/mL), when combined with membrane permeabilizers, efflux pump inhibitors, and clarithromycin, and exhibited narrow-spectrum efficacy against H. pylori, providing a novel strategy for anti-H. pylori therapy.

The escalating antibiotic resistance presents formidable challenges in the treatment of Gram-negative bacterial infections. Clinically, these bacteria have also acquired resistance to polymyxin, the last resort of defense. Novel antibiotics with a single mode of action are susceptible to rapid resistance development, and sometimes asynchronous pharmacokinetics also hinders the effectiveness of combined administration strategies in vivo. Here, we developed a class of novel bifunctional antibacterial peptides by covalently conjugating a series of modified PbgA-derived peptides with colistin analog (PE-2C-C8-DH) via a small-molecule linker (KCM02). These bifunctional peptides show remarkable synergistic antibacterial efficacy, where “1 + 1 > 2”, against various priority multidrug-resistant Gram-negative bacteria, involving polymyxin-resistant strains. By optimizing the structure-activity relationship, two compounds (BP-28 and BP-37) with distinct activity preferences were obtained, which possess rapid bactericidal efficacy and a significantly lower risk of resistance compared to single-mode-of-action antibacterial agents, without hemolytic toxicity and cytotoxicity. Identification of antibacterial targets revealed that they can damage Gram-negative bacterial membrane by targeting LPS and BamA. Our study offers a referable approach for the development of novel antimicrobial agents.

BACKGROUND:Sepsis is associated with high morbidity and high mortality and has strongly motivated intense studies into its mechanisms. Antibiotics, aimed to eradicate bacteria, have some impact on the immune system due to anti-inflammatory properties. Tigecycline, an antibiotic of the glycylcycline class, is commonly used for severe infections. PURPOSE:This study aimed to investigate tigecycline's mechanism on the inflammatory response of sepsis to find new targets for sepsis treatment. The objective included (i) to observe the changes in inflammatory factors in LPS (lipopolysaccharide) induced septic mice after tigecycline administration, (ii) to detect the effect of tigecycline on macrophages NF-κB (nuclear factor kappa B) signalling. METHODS:For LPS-induced sepsis in mice and intervention with tigecycline, mice were first injected with tigecycline (6.5 mg/kg) via tail vein followed by LPS (15 mg/kg). Luminex analysis was performed on 16 mediators. NF-κB signalling pathway antibody chip detected the expression of target sites in macrophages of the LPS group and tigecycline + LPS group. RESULTS:Tigecycline has inhibitory effects on LPS-induced inflammatory response in septic mice, decreasing the concentrations of IL (interleukin)-6, IL-27, TNF-α (tumour necrosis factor-α), TNF RII, IFN-γ (interferon-gamma), CCL5/RANTES (CC Motif Chemokine Ligand) while increasing IL-6Rα, IL-10, and TWEAK (TNF-related weak inducer of apoptosis). Tigecycline downregulated phosphorylation levels of key sites JNK (c-Jun N-terminal kinase)1/2/3, p-p65 (s468) and p-p105/p50 (s907) in NF-κB signalling. CONCLUSIONS:Tigecycline may inhibit the excessive immune response induced by LPS in sepsis, which may cause a potential protective effect on the host through immune regulation.

Inhaled formulations are the first choices for treating asthma and chronic obstructive pulmonary disease (COPD). Both local and systemic exposures need to be considered when assessing the efficacy and safety of inhaled drugs. Physiologically-based pharmacokinetic (PBPK) models were constructed and verified for budesonide and formoterol with different inhalation devices, CXG87 (test (T) formulation) and Symbicort® Turbuhaler® (reference (R) formulation). The models were then used to evaluate local exposures at different peak inspiratory flow rates (PIFRs) and dose conditions. Local exposures of CXG87 were comparable to the R formulation at PIFR 50-80 L/min at the dose of 200 μg/6 μg (budesonide/ formoterol fumarate), which was determined as the recommended dose. At this dose, CXG87 had local exposure advantages compared with the R formulation at PIFR 30-50 L/min and better local exposure stability at PIFR 30-80 L/min in the indication population. The simulation results indicated that 200 μg/6 μg can be selected as the study dose in the subsequent clinical study of CXG87 in indication patients. In addition, the clinical study could also include a lower flow rate (30-50 L/min) patient population to further evaluate the advantages of the modified formulation CXG87. This is the first study to predict CXG87 local exposure by a verified PBPK model.

Rose essential oil (REO) has an inhibitory effect on the growth of Cutibacterium acnes (C. acnes). In this work, scanning electron microscopy, fluorescence spectroscopy, microbial metabolomics based on gas chromatography-time-of-flight mass spectrometry (GC-TOFMS), as well as multivariate statistical analysis and machine learning feature selection algorithms were utilized to investigate the antimicrobial mechanism of REO against C. acnes. The results showed that the minimum inhibitory concentration of REO against C. acnes was 0.025% (V/V), and the minimum bactericidal concentration was 0.050% (V/V). Under REO exposure, the time for C. acnes to enter the logarithmic growth phase was significantly delayed, and the delay time increased with the increase of REO concentration. The subinhibitory concentration of REO caused varying degrees of wrinkling, depression, and damage to membrane permeability and integrity, with a significant dose-effect relationship. A total of 254 kinds of metabolites were identified by comparing with FiehnLib and a self-built database using the high-coverage metabolic footprinting analysis approach. Among them, 12 kinds of feature markers which were strongly associated with the antimicrobial effect of REO were obtained, through orthogonal partial least squares discriminant analysis (OPLS-DA) and Student ' s t-test, as well as the random forest recursive feature elimination (RFRFE) algorithm based on Scikit and bioinformatics analysis. These characteristic markers mainly involve metabolic pathways including phenylalanine, tyrosine and tryptophan biosynthesis, glycine, serine and threonine metabolism, arginine biosynthesis, one carbon pool by folate, and glutathione metabolism (p<0.05, FDR<0.05). Protein targets such as fumarate hydrase (FH), serine dehydrase (SDS), glutamate dehydrogenase (GLUD1), glutamine synthase (GLUL), serine hydroxymethyltransferase (SHMT1), and glutathione synthase (GSS), which were closely related to energy metabolism, nitrogen metabolism, nucleotide synthesis and antioxidant defense, were possibly associated. The integration of microbial metabolomics and machine learning strategies provided reference data for in-depth revealing the metabolic regulatory mechanism of REO against C. acnes.

Cancer cells employ various mechanisms to evade immune surveillance. Their surface features, including a protective “sugar coat” and immune checkpoints like PD-L1 (programmed death ligand 1), can impede immune cell recognition. Sialic acids, which carry negative charges, may hinder cell contact through electrostatic repulsion, while PD-L1 transmits immunosuppressive signals to T cells. Furthermore, cancer cells manipulate macrophages within the tumor microenvironment to facilitate immune escape. Prior research has demonstrated the effectiveness of separately blocking the PD-L1 and sialic acid pathways in eliciting anti-tumor effects. In this study, we investigated the relationship between PD-L1 expression and genes associated with sialic acid in clinical databases. Subsequently, we developed a novel nanobody enzyme fusion protein termed Nb16-Sia to simultaneously target both PD-L1 and sialic acid pathways. In vivo experiments confirmed the anti-tumor activity of Nb16-Sia and highlighted its dependence on macrophages. Further investigations revealed that Nb16-Sia could polarize macrophages towards the M1 phenotype through the C-type lectin pathway in vitro and eliminate tumor-associated macrophages in vivo. In conclusion, our findings demonstrate that the fusion of PD-L1 nanobody with sialidase effectively targets tumor-associated macrophages, resulting in significant anti-tumor effects. This approach holds promise for drug development aimed at enhancing immune responses against cancer. ### Competing Interest Statement The authors have declared no competing interest.

New Delhi metallo-beta-lactamase-1 (NDM-1) has rapidly disseminated worldwide, leading to multidrug resistance and worse clinical prognosis. Designing and developing effective NDM-1 inhibitors is a critical and urgent challenge. In this study, we constructed a library of long-lasting nitroxoline derivatives and identified ASN-1733 as a promising dual-functional antibiotic. ASN-1733 can effectively compete for Ca2+ on the bacterial surface, causing the detachment of lipopolysaccharides (LPS), thereby compromising the outer membrane integrity and permeability and exhibiting broad-spectrum bactericidal activity. Moreover, ASN-1733 demonstrated wider therapeutic applications than nitroxoline in mouse sepsis, thigh and mild abdominal infections. Furthermore, ASN-1733 can effectively inhibit the hydrolytic capability of NDM-1 and exhibits synergistic killing effects in combination with meropenem against NDM-1 positive bacteria. Mechanistic studies using enzymatic experiments and computer simulations revealed that ASN-1733 can bind to key residues on Loop10 of NDM-1, hindering substrate entry into the enzyme's active site and achieving potent inhibitory activity (K-i = 0.22 mu M), even in the presence of excessive Zn2+. These findings elucidate the antibacterial mechanism of nitroxoline and its derivatives, expand their potential application in the field of antibacterial agents and provide new insights into the development of novel NDM-1 inhibitors. [GRAPHICS] .

Disorder of complement response is a significant pathogenic factor causing some autoimmune and inflammation diseases. The Ornithodoros moubata Complement Inhibitor (OmCI), a small 17 kDa natural protein, was initially extracted from soft tick salivary glands. The protein was found binding to complement C5 specifically, inhibiting the activation of the complement pathway, which is a successful therapeutic basis of complement-mediated diseases. However, a short half-life due to rapid renal clearance is a common limitation of small proteins for clinical application. In this study, we extended the half-life of OmCI by modifying it with fatty acid, which was a method used to improve the pharmacokinetics of native peptides and proteins. Five OmCI mutants were initially designed, and single-site cysteine mutation was introduced to each of them. After purification, four OmCI mutants were obtained that showed similar in vitro biological activities. Three mutants of them were subsequently coupled with different fatty acids by nucleophilic substitution. In total, 15 modified derivatives were screened and tested for anticomplement activity in vitro. The results showed that coupling with fatty acid would not significantly affect their complement-inhibitory activity (CH50 and AH50). OmCIT90C-CM02 and OmCIT90C-CM05 were validated as the applicable OmCI bioconjugates for further pharmacokinetic assessments, and both showed improved plasma half-life in mice compared with unmodified OmCI (15.86, 17.96 vs 2.57 h). In summary, our data demonstrated that OmCI conjugated with fatty acid could be developed as the potential long-acting C5 complement inhibitor in the clinic.

Acinetobacter baumannii has developed multiple drug resistances, posing a significant threat to antibiotic efficacy. LysECD7, an endolysin derived from phages, could be a promising therapeutic agent against multi-drug resistance A. baumannii. In this study, in order to further enhance the antibacterial efficiency of the engineered LysECD7, a few lipopolysaccharide-interacting peptides (Li5, MSI594 and Li5-MSI) were genetically fused with LysECD7. Based on in vitro antibacterial activity, the fusion protein Lys-Li5-MSI was selected for further modifications aimed at extending its half-life. A cysteine residue was introduced into Lys-Li5-MSI through mutation (Lys-Li5-MSIV12C), followed by conjugation with a C16 fatty acid chain via a protonation substitution reaction(V12C-C16). The pharmacokinetic profile of V12C-C16 exhibited a more favorable characteristic in comparison to Lys-Li5-MSI, thereby resulting in enhanced therapeutic efficacy against lethal A. baumannii infection in mice. The study provides valuable insights for the development of novel endolysin therapeutics and proposes an alternative therapeutic strategy for combating A. baumannii infections.

Carbapenem-resistant Acinetobacter baumannii (CRAB) is a Priority 1 (Critical) pathogen urgently requiring new antibiotics. Polymyxins are a last-line option against CRAB-associated infections. This transcriptomic study utilized a CRAB strain to investigate mechanisms of bacterial killing with polymyxin B, colistin, colistin B, and colistin/sulbactam combination therapy. After 4h of 2mg/L polymyxin monotherapy, all polymyxins exhibited common transcriptomic responses which primarily involved disruption to amino acid and fatty acid metabolism. Of the three monotherapies, polymyxin B induced the greatest number of differentially expressed genes (DEGs), including for genes involved with fatty acid metabolism. Gene disturbances with colistin and colistin B were highly similar (89% common genes for colistin B), though effects on gene expression were generally lower (0-1.5-fold in most cases) with colistin B. Colistin alone (2mg/L) or combined with sulbactam (64mg/L) resulted in rapid membrane disruption as early as 1h. Transcriptomic analysis of this combination revealed that the effects were driven by colistin, which included disturbances in fatty acid synthesis and catabolism, and inhibition of nutrient uptake. Combination therapy produced substantially higher fold changes in 72% of DEGs shared with monotherapy, leading to substantially greater reductions in fatty acid biosynthesis and increases in biofilm, cell wall, and phospholipid synthesis. This indicates synergistic bacterial killing with the colistin/sulbactam combination results from a systematic increase in perturbation of many genes associated with bacterial metabolism. These mechanistic insights enhance our understanding of bacterial responses to polymyxin mono- and combination therapy and will assist to optimize polymyxin use in patients.

LYSC98 is a vancomycin derivative used for gram-positive bacterial infections therapy. We reported the pharmacokinetic/pharmacodynamic (PK/PD) targets of LYSC98 against Staphylococcus aureus using a murine thigh infection model. Three Staphylococcus aureus strains were utilized. Single-dose plasma pharmacokinetics of LYSC98 were determined in infected mice after the tail vein injection of 2, 4, and 8mg/kg. The results showed maximum plasma concentration (C max ) 11466.67 - 48866.67 ng/mL, area under the concentration-time curve from 0 to 24 h(AUC 0-24 ) 14788.42 -91885.93 ng/mL·h, and elimination half-life(T 1/2 ) 1.70-2.64 h, respectively. The C max (R 2 0.9994) and AUC 0-24 (R 2 0.981) were positively correlated with the dose of LYSC98 in the range of 2-8 mg/kg. Dose fractionation studies using total doses of 2 to 8 mg/kg administered with q6h, q8h, q12h, and q24h were performed to evaluate the correlation of different PK/PD indices with efficacy. Sigmoid model analysis showed C max /MIC (R 2 0.8941) was the best PK/PD index to predict the efficacy of LYSC98. In the dose ranging studies, two Methicillin-resistant Staphylococcus aureus (MRSA) clinical strains were used to infect the mice and 2-fold-increasing doses (1 to 16 mg/kg) of LYSC98 were administered. The magnitude of LYSC98 C max /MIC associated with net stasis, 1, 2, 3 and 4 - log10 kill were 5.78, 8.17, 11.14, 15.85 and 30.58, respectively. The results of this study showed LYSC98 a promising antibiotic with in vivo potency against MRSA, and will help in the dose design of phase one study for LYSC98.

Backgroud: Breast cancer is a prevalent malignancy among women, with triple-negative breast cancer (TNBC) comprising approximately 15-20% of all cases, possessing high invasiveness, drug resistance and poor prognosis. Chemotherapy, the main treatment for TNBC, is limited by toxicity and drug resistance. Apolipoprotein A1 modified doxorubicin liposome (ApoA1-lip/Dox) was constructed in our previous study, with promising anti-tumour effect and improved safety been proved. However, during long-term administration, the problem of cumulative toxicity and insufficient tumour inhibition is still inevitable. Interleukin-21 is a small molecule protein secreted by T cells with various immune regulatory functions. IL-21 has significantly curative effects in numerous solid tumours, but it has the disadvantages of low response rate and short half-life. The combination of chemotherapy and immunotherapy has received increasing attention.Purpose: In this study, ApoA1 drug loading system and long-acting IL-21 are innovatively combined for tumour treatment.Methods: We combined ApoA1-lip/Dox and IL-21 for treatment and evaluated their impact on tumor-infiltrating lymphocytes and CD8+ T and NK cell cytotoxicity.Results: Combined administration significantly improved the tumour-infiltrating lymphocytes and enhanced the cytotoxicity of CD8+ T and NK cells. The combination of ApoA1-lip/Dox and IL-21 exhibits significantly enhanced anti-tumour efficacy with lower toxicity of ApoA1-lip/Dox, providing a new strategy for TNBC treatment with enhanced anti-tumour response and reduced toxicity.

Objective To investigate whether tigecycline can regulate the inflammatory response induced by lipopolysaccharide（LPS） in vivo and in vitro. Methods The effect of tigecycline on the proliferation activity of mouse mononuclear macrophages RAW264.7 was studied in vitro. The regulatory effect of tigecycline on the LPS-induced inflammatory response of RAW264.7 was investigated in vitro. Tigecycline was added to the cell suspension, followed by addition of LPS. The supernatants were collected at different time points in each test group. The level of cytokines was detected by ELISA. Low-dose LPS-induced inflammatory response was also studied in vivo. Mice were injected with tigecycline（6.5 mg/kg） via tail vein, followed by injection of LPS（15mg/kg） 2 hours later. Serum cytokines levels were detected by ELISA at each time point. The spleen was tested by flow cytometry after animal death. The mortality was recorded up to 24 hours. Results Tigecycline promoted the proliferation of macrophage RAW264.7. In vitro, tigecycline inhibited the inflammatory response of RAW264.7 cells induced by LPS and so reduced the release of IL-6, IFN-γ and CCL5 while increased the release of IL-10. Tigecycline also had a similar inhibitory effect on LPS-induced mice inflammatory response in vivo. Flow cytometry showed that tigecycline could promote M2 polarization of macrophages in endotoxemia. It has a protective effect on the death of mice. Conclusions Tigecycline has an immunomodulatory effect on LPSinduced inflammation, can inhibit the excessive immune reaction, and so has a protective effect on the host.

目的 探究硝羟喹啉在体外和小鼠体内提高碳青霉烯类耐药菌对美罗培南敏感性的方法.方法 通过肉汤微量稀释法,测定硝羟喹啉对不同类型碳青霉烯类耐药菌(大肠埃希菌3株、肺炎克雷伯菌1株、鲍曼不动杆菌1株)和大肠埃希菌标准菌株ATCC 25922的最低抑菌浓度(MIC);利用扫描电镜,观察硝羟喹啉作用后细菌形态学改变.通过肉汤微量稀释棋盘法,计算硝羟喹啉和美罗培南的部分抑菌浓度指数(FICI);建立小鼠尿路感染模型,探索硝羟喹啉和美罗培南联合治疗对碳青霉烯类耐药菌感染的体内药效.结果 硝羟喹啉单药在体外对标准菌株和临床耐药菌株均有一定抗菌活性,MIC范围1～4 mg/L;硝羟喹啉作用后,细菌表面出现不同程度的损伤,且与药物浓度呈正相关;回补Ca2+或Zn2+均使硝羟喹啉MIC值增加;硝羟喹啉与美罗培南联用,对产NDM-1耐药大肠埃希菌的FICI为0.1875,对产KPC-2型肺炎克雷伯菌和产OXA-23型鲍曼不动杆菌的FICI为2.在小鼠尿路感染治疗中,联合用药组小鼠尿液中细菌含量降低3.076 log10 CFU/mL,抗菌药效显著优于对照组和单药治疗组(P＜0.000 1).结论 硝羟喹啉可通过螯合二价金属离子,抑制细菌生长,也可以在体外和小鼠体内提高产NDM-1碳青霉烯类耐药大肠埃希菌对美罗培南的敏感程度.

猴头菇多糖是从食药真菌猴头菇(Hericium erinaceus)的子实体、菌丝体或发酵培养液中提取的一类活性大分子.近年来,关于猴头菇多糖通过改变肠道菌群来调节免疫、缓解炎症性肠病、影响神经系统及代谢性疾病的研究日益增多.猴头菇多糖可通过促进肠道益生菌增殖、抑制致病菌生长、增加短链脂肪酸生成、增强肠道免疫及激活特定信号通路发挥健康促进作用.这些生物活性与猴头菇多糖的结构有关.该文总结了不同来源猴头菇多糖的结构特征及对肠道菌群多样性的影响,综述了猴头菇多糖通过调节肠道菌群促进健康的积极作用及可能机制,并列举了其在多领域的应用和开发前景,为猴头菇多糖调控肠道微生物稳态的深入探索提供了理论依据,也为猴头菇多糖类益生元制剂的开发利用提供了参考.