查找使用阿拉丁产品的科研文献

Enhanced conversion of sterols to steroid synthons by augmenting the peptidoglycan synthesis gene pbpB in Mycobacterium neoaurum

Wan-Ju Sun,Yong-Jun Liu,Hao-Hao Liu,Jie-De Ma,Yu-Hong Ren,Feng-Qing Wang,Dong-Zhi Wei

Some species of mycobacteria have been modified to transform sterols to valuable steroid synthons. The unique cell wall of mycobacteria has been recognized as an important organelle to absorb sterols. Some cell wall inhibitors (e.g., vancomycin and glycine) have been validated to enhance sterol conversion by interfering with transpeptidation in peptidoglycan biosynthesis. Therefore, two transpeptidase genes, pbpA and pbpB , were selected to rationally modify the cell wall to simulate the enhancement effect of vancomycin and glycine on sterol conversion in a 22-hydroxy-23,24-bisnorchol-4-ene-3-one (4-HBC) producing strain (WIII). Unexpectedly, the pbpA or pbpB gene augmentation was conducive to the utilization of sterols. The pbpB augmentation strain WIII- pbpB was further investigated for its better performance. Compared to WIII, the morphology of WIII- pbpB was markedly changed from oval to spindle, indicating alterations of the cell wall. Biochemical analysis indicated that the altered cell wall properties of WIII- pbpB might contribute to the positive effect on sterol utilization. The productivity of 4-HBC was enhanced by 28% in the WIII- pbpB strain compared to that of WIII. These results demonstrated that the modification of peptidoglycan synthesis can improve the conversion of sterols to steroid synthons in mycobacteria.

Mycobacterium tuberculosis RKIP (Rv2140c) dephosphorylates ERK/NF-κB upstream signaling molecules to subvert macrophage innate immune response

M.A. Abo-Kadoum,Mohammed Assad,Moure UAE,Stech A.E. Nzaou,Zhen Gong,Asmaa Moaaz,Samson Teweldebrhan,Adel Eltoukhy,Ai Xuefeng,Yu Chen,Jianping Xie

Mycobacterium tuberculosis (Mtb) survival and virulence largely reside on its ability to manipulate the host immune response . We have previously shown that M. tuberculosis Raf kinase inhibitor protein (RKIP) Rv2140c regulates diverse phosphorylation events in M. smegmatis . However, its role during infection is unknown. In this report, we show that Rv2140c can mimic the mammalian RKIP function. Rv2140c inhibit the activation of extracellular signal-regulated kinase (ERK) and nuclear factor κB (NF-κB) via decreasing the phosphorylation capacity of upstream mediators MEK1, ERK1/2, and IKKα/β, thus leading to a reduction in pro-inflammatory cytokines IL-1β, IL-6, and TNF-α. This effect can be reversed by RKIP inhibitor locostatin. Furthermore Rv2140c mediates apoptosis associated with activation of caspases cascades. This modulation enhances the intracellular survival of M. smegmatis within macrophage. We propose that Rv2140c is a multifunctional virulence factor and a promising novel anti-Tuberculosis drug target.

A multicomponent propane monooxygenase catalyzes the initial degradation of methyl tert-butyl ether in Mycobacterium vaccae JOB5

Yiyang Chen,Hao Ren,Xiangyu Kong,Hao Wu,Zhenmei Lu

Cochilimycin B Is a Potential Anti-Mycobacterium marinum Medicine Through Screening the 14-Membered Resorcylic Acid Lactones Library

Jing Qianqian,Cheng Yajie,Wang Wenhui,Yin Junna,Wei Meiyan,Xu Tongyi,Shao Changlun

Mycobacterium marinum can cause disease in both human beings and fishes. Infected fish exhibits symptoms commonly referred to as fish tuberculosis. In this research, we screened a 14-Membered Resorcylic Acid Lactones (RALs) library constructed in the laboratory for in vitro anti- Mycobacterium marinum activity and found that several compounds, including compounds 3 , 4 , 6 , 10 , and 17 – 26 , showed good activity. Notably, the trace natural product cochilimycin B (compound 3 ) possesses significant long-lasting inhibitory function to Mycobacterium marinum . It also shows synergistic effects with drugs like isoniazid, ethambutol, and bedaquiline ( FICI ≤0.5). In addition, cochilimycin B showed a significant inhibitory effect on the biofilm produced by Mycobacterium marinum , with an inhibition rate of 65.9%. To solve the bottleneck problem of natural product drug sources, we realized an efficient one-step semi-synthetic method to obtain compound 3 with a yield of 32.1%. In vivo , inflammatory changes in BALB/c mice infected with Mycobacterium marinum were characterized. After 12 h of infection, IL-1 β was 20%–30% lower in the spleen and tail of the 3 -treated group compared to the control group. In the thymus and tail of the treated group, TNF- α levels were 30%–60% lower than in the control group. This is the first time that the significant anti- Mycobacterium marinum effect of cochilimycin B from 14-Membered Resorcylic Acid Lactones (14-RALs) was reported, offering a new chemical molecule for anti- Mycobacterium marinum drug research.

The function of steroid terminal monooxygenase in cholesterol or phytosterol degradation by the Mycobacterium neoaurum NRRL B-3805

Li Xuemei,Zhang Rui,Li Jianjiong,Feng Jinhui,Wu Qiaqing,Zhu Dunming,Ma Yanhe

Cholesterol and phytosterols can be served as the substrates for Actinobacteria to produce the precursors used in the synthesis of steroidal medicines. Cytochrome P450s from CYP125 and CYP142 families initiates the metabolism of cholesterol and/or phytosterols. In this study, we demonstrate the functional redundancy and substrate preference of five cytochrome CYP125s and CYP142s by the unmarked cyp genes deletion strains of Mycobacterium neoaurum NRRL B-3805. CYP125-3 was found to be responsible for the catalytic hydroxylation of both cholesterol and the C24-branched side-chains of phytosterols, while CYP142-2 can only oxidize cholesterol and/or cholest-4-en-3-one. The strain harboring the CYP125-3 produced 6.47 g l − 1 and 5.13 g l − 1 of 4-androstene-3,17-dione (AD) when 15 g l − 1 cholesterol or 17.5 g l − 1 phytosterols used, respectively. While, the strain harboring the CYP142-2 produced 7.10 g l − 1 AD when 15 g l − 1 cholesterol used. The other three cytochrome P450s have a smaller contribution for the degradation of cholesterol and phytosterols. CYP125-3 has the hydroxylation activity on more substrates than that of CYP142-2. This study provided possible guidance to improve the efficiency of AD and other metabolites production from different kinds of sterols by the genetic manipulation.

Amplification-free electrochemiluminescence biosensors based on peptide-templated gold nanocluster and CRISPR-Cas12a for Mycobacterium tuberculosis IS6110 detection

Lingjun Cheng,Qingmei Yang,Yuanyuan Yang,Yufeng Wang,Qingfei He,Zhiyan Zou,Canping Su,Jiaming Chen,Yinhuan Liu,Guolin Hong

Background Tuberculosis (TB) nucleic acid diagnosis urgently requires rapid, amplification-free methods to overcome limitations of quantitative real-time polymerase chain reaction (qPCR), including instrument dependency, prolonged time, and contamination risks from nucleic acid amplification. Results Here, an amplification-free electrochemiluminescence (ECL) biosensor based on peptide-templated gold nanoclusters and the clustered regularly interspaced short palindromic repeats-Cas12a system (CRISPR-Cas12a) has been constructed for the detection of Mycobacterium tuberculosis (MTB)-specific IS6110 sequences. Peptide-templated gold nanoclusters with low background and high ECL response can be used as sensitive signal probes. When CRISPR-Cas12a recognizes the target IS6110 DNA, it exhibits non-specific cleavage activity, repeatedly cleaving ferrocene-labelled DNA. This results in the restoration of ECL signals quenched by ferrocene, thereby achieving signal amplification. There is a linear relationship between the signal and the target concentration range from 10 CFU/mL to 10 4  CFU/mL, with a detection limit of 7 CFU/mL (S/N = 3). Clinical validation ( n  = 40) showed strong agreement with qPCR ( κ  = 0.90). Significance Critically, this amplification-free strategy eliminates the need for temperature cycling equipment, reduces detection time to 1 h, and completely avoids the risk of amplicon contamination, providing an ideal solution for rapid screening of highly infectious diseases such as TB.

Construction of a Cell Factory for the Targeted and Efficient Production of Phytosterol to Boldenone in Mycobacterium neoaurum

Bo Zhang,Sifang Zhu,Yi Zhu,Xin Sui,Junping Zhou,Zhiqiang Liu,Yuguo Zheng

Boldenone (BD), a protein anabolic hormone, is commonly used to treat muscle damage, osteoporosis, and off-season muscle building in athletes. Traditional BD synthesis methods rely on chemical processes, which are costly and environmentally impactful. Therefore, developing a more sustainable and economical biosynthetic pathway is crucial for BD production. This study aimed to achieve efficient production of BD. Firstly, the catalytic performance of 17β-hydroxysteroid dehydrogenase and 3-ketosteroid-Δ 1 -dehydrogenase was improved through enzyme engineering, and their expression in the new strain of Mycobacterium neoaurum was enhanced using metabolic engineering. These improvements significantly increased BD production to 4.05 g/L, with a significant decrease in by-product generation. To further increase the yield, a multi-enzyme fusion expression system was constructed, and a key cell wall gene kasB was knocked out, resulting in a spatial-time yield of BD reaching 1.02 g/(L·d). Subsequent optimization of the transformation system further increased the BD production to 5.56 g/L, with a spatiotemporal yield of 1.39 g/(L·d). The green biosynthetic route of phytosterol one-step conversion to BD developed in this study lays the foundation for industrial production.

Mycobacterium tuberculosis Rv3717 enhances the survival of Mycolicibacterium smegmatis by inhibiting host innate immune and caspase-dependent apoptosis

Zhen Gong,Wenmin Yang,Hongyang Zhang,Xiaohong Xiang,Jie Zeng,Shuang Han,Jiao Yang,Jianping Xie

Tuberculosis caused by Mycobacterium tuberculosis ( M. tuberculosis ) infection remains a serious public threat despite decades of creative endeavors. There are few reports on the roles of M. tuberculosis enzymes involved in cell envelope biosynthesis in pathogen survival and persistence. M. tuberculosis Rv3717 encodes N -acetylmuramoyl-l-alanine amidase , a cell-wall hydrolase that hydrolyzes the bond between N -acetylmuramic acid and l-alanine in cell-wall peptidoglycan . In this paper, we demonstrated the Rv3717 promoted the survival of Mycolicibacterium smegmatis ( M. smegmatis ) within macrophages. More importantly, we demonstrated that this effect is because MS_Rv3717 reduces the release of host pro-inflammatory cytokines such as IL-1β, IL-6, IL-12 p40, TNF-α, and increased transcription of anti-inflammatory cytokine IL-10. At the same time, MS_Rv3717 inhibits apoptosis by inhibiting the activation of Caspase-3/9, reducing the host's elimination of M. smegmatis . Finally, from a bacterial perspective, we found Rv3717 decreased the survival of M. smegmatis under stresses such as SDS and low pH. This is the first report of the involvement of Mycobacterium cell envelope biosynthetic enzyme in host-pathogen interaction.

Picogram level electrochemical impedimetric immunosensor for monitoring Mycobacterium tuberculosis based on specific and sensitive ESAT-6 monoclonal antibody

Yanping Xia,Haibing Zhu,Ruixin Liu,Xin Li,Xiaoli Xie,Jie Zhao,Juan Li,Xin'an Jiao,Zhanjun Yang,Xiang Chen

Tuberculosis (TB) as a global epidemic disease is caused by Mycobacterium tuberculosis (M. tb). A small early secreted antigenic target 6-kDa protein (ESAT-6) secreted by M. tb has become a major virulence factor for detection of M. tb infection. Here, the recombinant protein His-CFP10-ESAT-6 (designated as rHis-CE) was expressed and purified as the immunogen to develop stable and specific ESAT-6 monoclonal antibodies (MAbs), which can recognize both recombinant and natural ESAT-6 protein. Three resultant ESAT-6 MAbs (named 4E1, 4D7 and 4G8) were characterized and screened in detail. An ultrasensitive electrochemical impedance ESAT-6 immunosensor for label-free detection of M. tb infection was proposed by the immobilization of the screening 4D7 ESAT-6 MAbs on the N-doped graphene oxide (N-GO) functionalized electrode. The structure and surface state of N-GO and ESAT-6 immunosensor were characterized by various characterization instruments such as transmission electron microscopy , X-ray photoelectron spectroscopy, contact angle measurement, and cyclic voltammetry . The quantitative detection of ESAT-6 was mainly achieved by recording the relative change of impedance before and after specificity reaction. Under the optimized conditions, ESAT-6 could be assayed in a range of 0.01–100 ng/mL with a very low detection limit of 7.0 pg/mL. Compared with the traditional assay methods, this immunosensor showed much higher sensitivity, wider linear range and simpler operation. Moreover, the ESAT-6 immunosensor showed good specificity, high reproducibility and excellent stability.

Dechlorination of dichloromethane by a biofilter enriched with electroactive bacteria: Performance, kinetics, and microbial community

Kaixiong Yang,Wenwen Wang,Lin Li

Dichloromethane (DCM) is a recalcitrant volatile organic compound that exhibits biological toxicity and bioaccumulation. In this study, gaseous DCM was removed using an electroactive bacterial biofilter (EBB) with graphite rod as the anode and carbon felt as the cathode. The highest removal efficiency (97.09%) was achieved at a cathodic potential of −600 mV (vs. Ag/AgCl). The EBB had a maximum elimination capacity of 79.29 g m −3  h −1 when the inlet load was 96.48 g m −3  h −1 . There was no substrate inhibition phenomenon observed in the EBB, and the Michaelis–Menten model was used to describe the kinetics of the EBB. High-throughput sequencing indicated that electroactive genera such as Rhodanobacter sp., Sphingomonas sp., Pseudomonas sp., Chryseobacterium sp . , Pseudochrobactrum sp., and Mycobacterium sp. dominated the EBB. The microbial communities were stable and were slightly affected by the DCM inlet concentration. The results can be applied for the effective treatment of recalcitrant volatile organic compounds (VOCs).

Triple-synergy bactericidal action: a mannose-decorated bioinspired coating on silver-mesoporous silica for eradicating multidrug-resistant Mycobacterium tuberculosis

Yiyan Song,Dawei Yu,Zhijie Sheng,Huafeng Song,Junchi Xu,Jianping Zhang,Hui Chen,Ping Xu

Tuberculosis, the world's leading cause of death from a single infectious agent in 2023, is exacerbated by the rising prevalence of multidrug-resistant (MDR) Mycobacterium tuberculosis, underscoring an urgent need for novel therapeutic agents. In this study, we developed a green in situ synthesis strategy for silver nanoparticles (Ag NPs) utilizing polydopamine (PDA) as a biomimetic reducing and coating agent on mesoporous silica (SBA-15). The material was further co-coated with the antimicrobial polymer epsilon-poly-L-lysine (EPL) and functionalized with mannose via a Schiff-base reaction. The resulting composite, denoted as Ag@SBA-15/Man-PDA-EPL, was comprehensively characterized by physicochemical techniques and exhibited low cytotoxicity. Mycobacterium tuberculosis (H37Rv and MDR) was used for the evaluation of the prepared nanocomposites in which the components (Ag@SBA-15/PDA and EPL) exhibited synergistic effect towards MDR. The mannose-grafted composite (Ag@SBA-15/Man-PDA-EPL) exhibited significantly enhanced anti-tubercular efficacy compared to its non-functionalized counterpart (Ag@SBA-15/PDA-EPL), an improvement attributed to the antibacterial capability conferred by the Schiff-base formation. Transmission electron microscopy (TEM) imaging confirmed extensive cellular damage in mycobacteria treated with Ag@SBA-15/Man-PDA-EPL. This study validates a rational combination strategy integrating silver nanoparticles, EPL, and ligand-specific targeting via a Schiff-base moiety into a unified nanoplatform, offering a promising approach to combat drug-resistant tuberculosis and mitigate nosocomial infections.

Mycobacterium tuberculosis PE_PGRS45 (Rv2615c) Promotes Recombinant Mycobacteria Intracellular Survival via Regulation of Innate Immunity, and Inhibition of Cell Apoptosis

Xu Tao,Wang Chutong,Li Minying,Wei Jing,He Zixuan,Qian Zhongqing,Wang Xiaojing,Wang Hongtao

Tuberculosis (TB), a bacterial infectious disease caused by Mycobacterium tuberculosis (M. tuberculosis ), is a significant global public health problem. Mycobacterium tuberculosis expresses a unique family of PE_PGRS proteins that have been implicated in pathogenesis. Despite numerous studies, the functions of most PE_PGRS proteins in the pathogenesis of mycobacterium infections remain unclear. PE_PGRS45 (Rv2615c) is only found in pathogenic mycobacteria. In this study, we successfully constructed a recombinant Mycobacterium smegmatis ( M. smegmatis ) strain which heterologously expresses the PE_PGRS45 protein. We found that overexpression of this cell wall-associated protein enhanced bacterial viability under stress in vitro and cell survival in macrophages. MS_PE_PGRS45 decreased the secretion of pro-inflammatory cytokines such as IL-1β, IL-6, IL-12p40, and TNF-α. We also found that MS_PE_PGRS45 increased the expression of the anti-inflammatory cytokine IL-10 and altered macrophage-mediated immune responses. Furthermore, PE_PGRS45 enhanced the survival rate of M. smegmatis in macrophages by inhibiting cell apoptosis. Collectively, our findings show that PE_PGRS45 is a virulent factor actively involved in the interaction with the host macrophage.