Lethal factor

致死因子
  • 文章类型: Journal Article
    城市化和技术进步导致可能影响生态系统的内生电磁场(EMF)的分散。因此,了解它们对环境的影响很重要。水生生态系统作为各种电力来源的一部分受到EMF的影响,例如,高压输电线路(HVTL)。我们研究了HVTL产生的EMF对梭鱼(Esoxlucius)胚胎的空间排列和存活的影响。与没有人为EMF的对照组相比,受精卵在110kV和220kV的两种HVTL配置下孵育。监测胚胎取向和存活直至胚孔闭合。对照组在沿N-S排列的胚胎中显示出优势,NNW-SSE,和NNE-SSW轴,向北方向有轻微的流行。源自HVTL的EMF对梭鱼胚胎的空间排列没有显着影响,尽管观察到与对照组的安排有一些偏差。仅在110kV部位观察到胚胎死亡率增加,但可能是由于与EMF无关的因素。总之,HVTL产生的EMF不会显着改变派克胚胎的方向或存活机会。然而,长时间暴露或更高的EMF水平可能会引起明显的反应,随着电力网络继续更广泛地传播,需要进行持续的评估。
    Urbanization and technological advancements result in the dispersion of antropogenic electromagnetic fields (EMF) that can affect on ecosystems. Therefore, it is important to understand their impact on the environment. Aquatic ecosystems are subject to EMF as part of various electricity sources, e.g., high-voltage transmission lines (HVTL). We examined the impact of EMF generated by HVTL on the spatial arrangement and survival of pike (Esox lucius) embryos. Fertilized eggs were incubated under two HVTL configurations 110 kV and 220 kV compared with a control group devoid of anthropogenic EMF. Embryo orientation and survival were monitored until blastopore closure. The control group showed dominance in the arrangement of embryos along the N-S, NNW-SSE, and NNE-SSW axes, with a slight prevalence of northern directions. EMF originating from HVTL did not exert a significant influence on the spatial arrangement of pike embryos, although some deviations from the arrangement noticed in the control group were observed. Increased embryo mortality was observed only at 110 kV site, but probably due to factors unrelated to EMF. In conclusion, EMF generated by HVTL did not significantly change pike embryo orientation or chances of survival. However, longer exposure or higher EMF levels could provoke notable reactions, requiring ongoing evaluation as power networks continue to spread more widely.
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  • 文章类型: Journal Article
    炭疽芽孢杆菌的环境污染对人类健康构成不确定的威胁。我们进行了一项研究,以确定Türkiye东部卡尔斯炭疽流行地区的居民是否可以对炭疽毒素产生免疫反应,而不会发现临床感染。我们通过ELISA测量了279名志愿者血清中的抗PA和抗LFIgG抗体浓度,其中105人先前诊断为炭疽感染(100人皮肤,5胃肠)。在没有感染史的174人中,72之前曾接触过炭疽污染的物质。根据人口统计学参数对个体进行分类,日常工作环境,和住宅类型。这项研究中的所有村庄都记录了以前的动物或人类炭疽病例。逐步回归分析显示,先前的临床感染与两种抗体观察到的范围的上端浓度强烈相关。对于反PA,作为屠夫,持续暴露风险的持续时间与高浓度相关,当兽医或牧羊人时,自感染以来的时间,城镇住宅与低浓度相关。对于抗LF,乡村住宅与高浓度相关,而感染仅限于手指或拇指,与低浓度相关。线性判别分析确定了与已知的先前感染相关的抗体浓度谱。在已知先前感染的城市居民和没有感染史的兽医中观察到了先前感染的典型特征。四个没有感染史的人(两个屠夫,两名农村居民)的特征表明未发现先前的感染。因此,健康的人类似乎能够耐受低水平暴露于环境炭疽芽孢杆菌孢子而没有不良影响,但这种暴露是否具有保护性还有待确定。这些发现对负责降低受孢子污染的材料和环境对人类健康构成的风险的当局具有意义。
    Environmental contamination with Bacillus anthracis spores poses uncertain threats to human health. We undertook a study to determine whether inhabitants of the anthrax-endemic region of Kars in eastern Türkiye could develop immune responses to anthrax toxins without recognised clinical infection. We measured anti-PA and anti-LF IgG antibody concentrations by ELISA in serum from 279 volunteers, 105 of whom had previously diagnosed anthrax infection (100 cutaneous, 5 gastrointestinal). Of the 174 without history of infection, 72 had prior contact with anthrax-contaminated material. Individuals were classified according to demographic parameters, daily working environment, and residence type. All villages in this study had recorded previous animal or human anthrax cases. Stepwise regression analyses showed that prior clinical infection correlated strongly with concentrations at the upper end of the ranges observed for both antibodies. For anti-PA, being a butcher and duration of continuous exposure risk correlated with high concentrations, while being a veterinarian or shepherd, time since infection, and town residence correlated with low concentrations. For anti-LF, village residence correlated with high concentrations, while infection limited to fingers or thumbs correlated with low concentrations. Linear discriminant analysis identified antibody concentration profiles associated with known prior infection. Profiles least typical of prior infection were observed in urban dwellers with known previous infection and in veterinarians without history of infection. Four individuals without history of infection (two butchers, two rural dwellers) had profiles suggesting unrecognised prior infection. Healthy humans therefore appear able to tolerate low-level exposure to environmental B. anthracis spores without ill effect, but it remains to be determined whether this exposure is protective. These findings have implications for authorities tasked with reducing the risk posed to human health by spore-contaminated materials and environments.
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  • 文章类型: Journal Article
    目的:建立基于一维卷积神经网络的定量构效关系(1D-CNN-QSAR)模型,以识别新型炭疽抑制剂并分析化学空间。方法:我们开发了1D-CNN-QSAR模型来鉴定新型炭疽抑制剂。结果:1D-CNN-QSAR模型的统计结果显示,测试集的均方误差为0.045,预测相关系数为0.79。Further,化学空间分析显示80%以上的片段对相似性,与羧酸相关的活动悬崖,2-苯基呋喃,N-苯基二氢吡唑,N-苯基吡咯,呋喃,4-亚甲基-1H-吡唑-5-酮,苯基咪唑,苯基吡咯和苯基吡唑啉。结论:这些片段可以作为开发有效的炭疽新药候选物的基础。最后,我们得出的结论是,我们提出的1D-CNN-QSAR模型和指纹分析可能用于发现潜在的炭疽候选药物。
    Aim: To develop a one-dimensional convolutional neural network-based quantitative structure-activity relationship (1D-CNN-QSAR) model to identify novel anthrax inhibitors and analyze chemical space. Methods: We developed a 1D-CNN-QSAR model to identify novel anthrax inhibitors. Results: The statistical results of the 1D-CNN-QSAR model showed a mean square error of 0.045 and a predicted correlation coefficient of 0.79 for the test set. Further, chemical space analysis showed more than 80% fragment pair similarity, with activity cliffs associated with carboxylic acid, 2-phenylfurans, N-phenyldihydropyrazole, N-phenylpyrrole, furan, 4-methylene-1H-pyrazol-5-one, phenylimidazole, phenylpyrrole and phenylpyrazolidine. Conclusion: These fragments may serve as the basis for developing potent novel drug candidates for anthrax. Finally, we concluded that our proposed 1D-CNN-QSAR model and fingerprint analysis might be used to discover potential anthrax drug candidates.
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  • 文章类型: Journal Article
    炭疽芽孢杆菌致死毒素的中和是基础医学和实际保健的重要课题,关于对抗高度危险的感染。我们已经产生了针对炭疽芽孢杆菌致死毒素的中和单克隆抗体1E10,并描述了保护性抗原(PA)与真核细胞表面之间受体相互作用的阶段,PA低聚物的形成,致命毒素(LT)的组装,它通过内吞作用转移到真核细胞中,随后形成真正的孔并将LT释放到细胞胞质溶胶中。该抗体在炭疽芽孢杆菌与真核细胞相互作用阶段具有选择性作用,并揭示了1E10抗体的毒素中和活性机制。发现1E10单克隆抗体与PA之间的相互作用导致致死因子(LF)的酶活性受到抑制,很可能是由于PA破坏了真正的孔隙形成,阻止LF释放到细胞质中。
    Neutralization of the lethal toxin of Bacillus anthracis is an important topic of both fundamental medicine and practical health care, regarding the fight against highly dangerous infections. We have generated a neutralizing monoclonal antibody 1E10 against the lethal toxin of Bacillus anthracis and described the stages of receptor interaction between the protective antigen (PA) and the surface of eukaryotic cells, the formation of PA oligomers, assembly of the lethal toxin (LT), and its translocation by endocytosis into the eukaryotic cell, followed by the formation of a true pore and the release of LT into the cell cytosol. The antibody was shown to act selectively at the stage of interaction between Bacillus anthracis and the eukaryotic cell, and the mechanism of toxin-neutralizing activity of the 1E10 antibody was revealed. The interaction between the 1E10 monoclonal antibody and PA was found to lead to inhibition of the enzymatic activity of the lethal factor (LF), most likely due to a disruption of true pore formation by PA, which blocks the release of LF into the cytosol.
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  • 文章类型: Journal Article
    OBJECTIVE: One of the vital signaling pathways in cancer development and metastasis is mitogen-activated protein kinases (MAPKs). Bacillus anthracis Lethal Toxin (LT) is a potent MAPK signaling inhibitor. This toxin is comprised of two distinct domains, Lethal Factor (LF), MAPK inhibitor, and Protective Antigen (PA). To enter various cell lines, LF must be associated with the protective antigen (PA), which facilitates LF delivery. In the current study, to block MAPK signaling, LF was loaded into anti-CD19 immunoliposomes nanoparticle to deliver the cargo to Raji B cells.
    METHODS: The liposome nanoparticle was prepared using classical lipid film formation, then conjugated to anti-CD19 VHH. The binding efficiency was measured through flow cytometry. The targeted cytotoxicity of LF immunoliposome was confirmed by BrdU lymphoproliferation assay. This was followed by Real-Time PCR to assess the effect of formulation on pro-apoptotic genes. The inhibitory effect of LF on MAPK signaling was confirmed by western blot.
    RESULTS: Liposome nano-formulation was optimized to reach the maximum LF encapsulation and targeted delivery. Next, phosphorylation of MAPK pathway mediators like MEK1/2, P38 and JNK were inhibited following the treatment of Raji cells with LF-immunoliposome. The treatment also upregulated caspase genes, clearly illustrating cell death induced by LF through pyroptosis and caspase-dependent apoptosis.
    CONCLUSIONS: In conclusion, anti-CD19 VHH immunoliposome was loaded with LF, a potent MAPK inhibitor targeting B cells, which curbs proliferation and ushers B cells toward apoptosis. Thus, immunoliposome presents as a versatile nanoparticle for delivery of LF to block aberrant MAPK activation. To use LF as a therapy, it would be necessary to materialize LF without PA. In the current study, PA was substituted with anti-CD19 immunoliposome to make it targeted to CD19+ while keeping the normal cells intact.
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  • 文章类型: Journal Article
    炭疽芽孢杆菌分泌包含保护性抗原(PA)的三方毒素,水肿因子(EF),和致死因子(LF)。人类炭疽疫苗主要由炭疽保护性抗原(PA)组成。由于商业炭疽疫苗(人/兽医)的使用与若干限制相关,因此正在进行相当多的努力来提高疫苗的效力。
    在这项研究中,称为ELP的三重嵌合抗原(基因登录号:MT590758),包含PA的高免疫原性结构域,LF,EF是设计的,constructed,并评估豚鼠模型对炭疽的免疫能力。
    考虑抗原滴定和免疫方案进行免疫。在豚鼠中评估了ELP的免疫保护功效,并使用炭疽芽孢杆菌17JB菌株孢子的攻击测试将其与兽用炭疽疫苗的效力进行了比较。
    结果表明ELP抗原诱导强体液应答。发现ELP的T细胞反应与PA相似,并显示ELP可以保护100%,100%,100%,80%和60%的动物从50、70、90、100和120倍的最小致死剂量(MLD,等于5×105孢子/毫升),分别,在48小时内杀死对照动物。
    可以得出结论,ELP抗原具有针对炭疽的适当免疫的必要要求,可以用于开发针对炭疽的有效重组疫苗候选物。
    UNASSIGNED: Bacillus anthracis secretes a tripartite toxin comprising protective antigen (PA), edema factor (EF), and lethal factor (LF). The human anthrax vaccine is mainly composed of the anthrax protective antigen (PA). Considerable efforts are being directed towards improving the efficacy of vaccines because the use of commercial anthrax vaccines (human/veterinary) is associated with several limitations.
    UNASSIGNED: In this study, a triple chimeric antigen referred to as ELP (gene accession no: MT590758) comprising highly immunogenic domains of PA, LF, and EF was designed, constructed, and assessed for the immunization capacity against anthrax in a guinea pig model.
    UNASSIGNED: Immunization was carried out considering antigen titration and immunization protocol. The immunoprotective efficacy of the ELP was evaluated in guinea pigs and compared with the potency of veterinary anthrax vaccine using a challenge test with B. anthracis 17JB strain spores.
    UNASSIGNED: The results demonstrated that the ELP antigen induced strong humoral responses. The T-cell response of the ELP was found to be similar to PA, and showed that the ELP could protect 100%, 100%, 100%, 80% and 60% of the animals from 50, 70, 90, 100 and 120 times the minimum lethal dose (MLD, equal 5 × 105 spore/ml), respectively, which killed control animals within 48 h.
    UNASSIGNED: It is concluded that the ELP antigen has the necessary requirement for proper immunization against anthrax and it can be used to develop an effective recombinant vaccine candidate against anthrax.
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  • 文章类型: Journal Article
    Bacillus anthracis, the causative agent of anthrax is a Gram-positive, non-motile, spore forming bacterium. Its spores can persist in soil and water for years and can also be aerosolized. A rapid, sensitive and specific method to detect B. anthracis is important for clinical management and preventing spread of anthrax. Loop-mediated isothermal amplification (LAMP) assay is a rapid technique that amplifies target DNA in isothermal conditions with high sensitivity and specificity. In this study, a LAMP assay set targeting a chromosomal and two plasmid markers was developed. The individual assays of the LAMP set targeting pXO1 plasmid (lef), pXO2 plasmid (capB), and chromosome (BA5345) sequences could detect 10, 250, and 100 fg of genomic DNA and 10, 100, and 50 copies of the DNA targets harboured in recombinant plasmids, respectively. The lef and capB LAMP assays could detect ≥ 1 × 103 CFU per mL of bacteria in spiked human blood samples, while BA5345 LAMP assay could detect ≥ 1 × 104 CFU of bacteria per mL of spiked blood. The amplification was monitored in real-time by turbidimeter, and visual detection was also accomplished under normal and UV light after adding SYBR Green 1 dye on completion of the reaction. The assay set was found to be highly sensitive and did not cross-react with the closely related Bacillus spp. and other bacterial strains used in the study.
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  • 文章类型: Journal Article
    Anthrax lethal factor (LF) is a critical component of the anthrax toxin, and functions intracellularly as a zinc-dependent endopeptidase targeting proteins involved in maintaining critical host signaling pathways. To reach the cytoplasm, LF requires to be unfolded and guided through the narrow protective antigen pore in a pH-dependent process. The current study sought to address the question as to whether LF is capable of retaining its metal ion when exposed to a low-pH environment (similar to that found in late endosomes) and an unfolding stress (induced by urea). Using a combination of tryptophan fluorescence spectroscopy and chelation studies, we show that a decrease in the pH value (from 7.0 to 5.0) leads to a pronounced shift in the onset of structural alterations in LF to lower urea concentrations. More importantly, the enzyme was found to retain its Zn2+ ion beyond the unfolding transitions monitored by Trp fluorescence, a finding indicative of tight metal binding to LF in a non-native state. In addition, an analysis of red-edge excitation shift (REES) spectra suggests the protein to maintain residual structure (a feature necessary for metal binding) even at very high denaturant concentrations. Furthermore, studies using the chromophoric chelator 4-(2-pyridylazo)resorcinol (PAR) revealed LF\'s Zn2+ ion to become accessible to complexation at urea concentrations in between those required to cause structural changes and metal dissociation. This phenomenon likely originates from the conversion of a PAR-inaccessible (closed) to a PAR-accessible (open) state of LF at intermediate denaturant concentrations.
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  • 文章类型: Journal Article
    Anthrax toxins are produced by Bacillus anthracis throughout infection and shape the physiopathogenesis of the disease. They are produced in low quantities but are highly efficient. They have thus been long ignored, but recent biochemical methods have improved our knowledge in animal models. This article reviews the various methods that have been used and how they could be applied to clinical diagnosis.
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  • 文章类型: Journal Article
    Inhalational anthrax is rare and clinical experience limited. Expert guidelines recommend treatment with combination antibiotics including protein synthesis-inhibitors to decrease toxin production and increase survival, although evidence is lacking.
    Rhesus macaques exposed to an aerosol of Bacillus anthracis spores were treated with ciprofloxacin, clindamycin, or ciprofloxacin + clindamycin after becoming bacteremic. Circulating anthrax lethal factor and protective antigen were quantitated pretreatment and 1.5 and 12 hours after beginning antibiotics.
    In the clindamycin group, 8 of 11 (73%) survived demonstrating its efficacy for the first time in inhalational anthrax, compared to 9 of 9 (100%) with ciprofloxacin, and 8 of 11 (73%) with ciprofloxacin + clindamycin. These differences were not statistically significant. There were no significant differences between groups in lethal factor or protective antigen levels from pretreatment to 12 hours after starting antibiotics. Animals that died after clindamycin had a greater incidence of meningitis compared to those given ciprofloxacin or ciprofloxacin + clindamycin, but numbers of animals were very low and no definitive conclusion could be reached.
    Treatment of inhalational anthrax with clindamycin was as effective as ciprofloxacin in the nonhuman primate. Addition of clindamycin to ciprofloxacin did not enhance reduction of circulating toxin levels.
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