PROA

ProA
  • 文章类型: Journal Article
    神经坏死病毒(NNV),属于Betanodavirus的水生RNA病毒,感染各种海洋和淡水鱼,导致养殖幼虫和幼体大量死亡,并造成巨大的经济损失。环磷酸鸟苷-磷酸腺苷合酶(cGAS)被广泛认为是对源自不同病原体的胞质DNA的先天免疫应答中的中心成分。然而,对cGAS对水生RNA病毒的反应知之甚少。这项研究发现,石斑鱼cGAS(EccGAS)过表达抑制NNV复制,而EccGAS沉默促进NNV复制。EccGAS的抗NNV活性参与干扰素(IFN)信号激活,包括肿瘤坏死因子受体相关因子家族成员相关的NF-κB激活剂结合激酶1(TBK1)磷酸化,干扰素调节因子3(IRF3)核易位,以及随后诱导的IFNc和ISGs。有趣的是,NNV利用其衣壳蛋白(CP)或蛋白A(ProA)通过同时靶向EccGAS来负或正调节EccGAS介导的IFN信号传导。CP通过arm-P与EccGAS交互,S-P,和SD结构域,并以EcUBE3C(泛素连接酶)依赖性方式促进其聚泛素化与K48和K63连接,最终导致EccGAS降解。相反,ProA与EccGAS结合并抑制其泛素化和降解。在调节EccGAS蛋白含量时,CP的抑制作用比ProA的保护作用更明显,允许成功的NNV复制。这些新发现表明NNVCP和ProA动态调节EccGAS介导的IFN信号通路以促进NNV的免疫逃逸。我们的发现揭示了病毒与宿主相互作用的新机制,并为NNV的预防和控制提供了理论依据。重要的是众所周知的DNA传感器,cGAS是对抗DNA病毒的先天抗病毒免疫中的关键成分。尽管有越来越多的证据表明cGAS在抵抗RNA病毒中的功能,cGAS参与RNA病毒诱导的鱼类免疫反应的机制以及水生病毒如何逃避cGAS介导的免疫监视仍然难以捉摸。这里,我们研究了EccGAS正向调节抗NNV反应的详细机制。此外,NNVCP和ProA与EccGAS相互作用,通过泛素-蛋白酶体途径调节其蛋白质水平,动态调节EccGAS介导的IFN信号通路并促进病毒逃避。值得注意的是,NNVCP被鉴定为通过泛素连接酶EcUBE3C促进EccGAS的泛素化。这些发现揭示了水生RNA病毒逃避cGAS介导的先天免疫的新策略。增强我们对病毒-宿主相互作用的理解。
    Nervous necrosis virus (NNV), an aquatic RNA virus belonging to Betanodavirus, infects a variety of marine and freshwater fishes, leading to massive mortality of cultured larvae and juveniles and substantial economic losses. The enzyme cyclic guanosine monophosphate-adenosine monophosphate synthase (cGAS) is widely recognized as a central component in the innate immune response to cytosolic DNA derived from different pathogens. However, little is known about the response of cGAS to aquatic RNA viruses. This study found that Epinephelus coioides cGAS (EccGAS) overexpression inhibited NNV replication, whereas EccGAS silencing promoted NNV replication. The anti-NNV activity of EccGAS was involved in interferon (IFN) signaling activation including tumor necrosis factor receptor-associated factor family member-associated NF-kappa-B activator-binding kinase 1 (TBK1) phosphorylation, interferon regulatory factor 3 (IRF3) nuclear translocation, and the subsequent induction of IFNc and ISGs. Interestingly, NNV employed its capsid protein (CP) or Protein A (ProA) to negatively or positively modulate EccGAS-mediated IFN signaling by simultaneously targeting EccGAS. CP interacted with EccGAS via the arm-P, S-P, and SD structural domains and promoted its polyubiquitination with K48 and K63 linkages in an EcUBE3C (the ubiquitin ligase)-dependent manner, ultimately leading to EccGAS degradation. Conversely, ProA bound to EccGAS and inhibited its ubiquitination and degradation. In regulating EccGAS protein content, CP\'s inhibitory action was more pronounced than ProA\'s protective effect, allowing successful NNV replication. These novel findings suggest that NNV CP and ProA dynamically modulate the EccGAS-mediated IFN signaling pathway to facilitate the immune escape of NNV. Our findings shed light on a novel mechanism of virus-host interaction and provide a theoretical basis for the prevention and control of NNV.IMPORTANCEAs a well-known DNA sensor, cGAS is a pivotal component in innate anti-viral immunity to anti-DNA viruses. Although there is growing evidence regarding the function of cGAS in the resistance to RNA viruses, the mechanisms by which cGAS participates in RNA virus-induced immune responses in fish and how aquatic viruses evade cGAS-mediated immune surveillance remain elusive. Here, we investigated the detailed mechanism by which EccGAS positively regulates the anti-NNV response. Furthermore, NNV CP and ProA interacted with EccGAS, regulating its protein levels through ubiquitin-proteasome pathways, to dynamically modulate the EccGAS-mediated IFN signaling pathway and facilitate viral evasion. Notably, NNV CP was identified to promote the ubiquitination of EccGAS via ubiquitin ligase EcUBE3C. These findings unveil a novel strategy for aquatic RNA viruses to evade cGAS-mediated innate immunity, enhancing our understanding of virus-host interactions.
    导出

    更多引用

    收藏

    翻译标题摘要

    我要上传

       PDF(Pubmed)

  • 文章类型: Journal Article
    蛋白A(ProA)高效液相色谱(HPLC)由于其高特异性和效率,是用于测量单克隆抗体(mAb)滴度的常用分析方法。此程序的准确和可靠的结果是必要的,因为对于过程中样品存在的总mAb的定量直接影响与过程相关杂质的去除相关的下游纯化步骤。本研究旨在改进以前使用传统方法开发的平台ProAHPLC分析程序,但并不总是可靠的。通过回顾性应用设计质量分析(AQbD)原则和性能统计评估,确定了由于蛋白质吸附到普通样品小瓶材料而导致的校准标准中的偏差。对用作样品稀释剂的流动相中包含Tween®20进行了优化,以确保程序性能并提高分析范围。使用实验设计(DoE)方法评估所得程序的鲁棒性,并根据监管机构推荐的分析目标概况(ATP)标准验证性能。结果线性显示R2值为1.00,截距偏差为1.2%(分析师1)和0.8%(分析师2),所有水平的准确性报告为99.2%的回收率,中间精密度报告为3.0%RSD。此后,这种新平台程序的应用将新mAb产品的开发时间线减少了50%,并且允许准确的滴度测定以支持>5个早期阶段产品特定的工艺决策,而不需要广泛的分析程序开发。这项工作展示了采用AQbD概念的实用性和相对容易性,即使是既定的程序,并通过生命周期方法来支持他们管理过程性能。
    Protein A (ProA) high-performance liquid chromatography (HPLC) is a common analytical procedure for measuring monoclonal antibody (mAb) titers due to its high specificity and efficiency. Accurate and reliable results of this procedure are imperative, as the quantitation of the total mAb present for in-process samples directly impacts downstream purification steps related to the removal of process-related impurities. This study aimed to improve a platform ProA HPLC analytical procedure which was previously developed using traditional approaches and was not always reliable. By retrospectively applying Analytical Quality by Design (AQbD) principles and statistical assessments of performance, a bias in the calibration standard due to protein-adsorption to common sample vial materials was identified. The inclusion of Tween® 20 into the mobile phase used as sample diluent was optimized to ensure procedure performance and improve analytical range. The resulting procedure robustness was evaluated using Design of Experiment (DoE) approaches and performance was verified against Analytical Target Profile (ATP) criteria as recommended by regulatory agencies. The resulting linearity displayed R2 values of 1.00 with intercept biases of 1.2 % (analyst 1) and 0.8 % (analyst 2), accuracy across all levels was reported at 99.2 % recovery, and intermediate precision was reported as 3.0 % RSD. Application of this new platform procedure has since reduced development timelines for new mAb products by 50 % and allowed for accurate titer determination to support >5 early phase product-specific process decisions without requiring extensive analytical procedure development. This work demonstrates the utility and relative ease of adopting AQbD concepts, even for established procedures, and supporting them with a lifecycle approach to managing procedure performance.
    导出

    更多引用

    收藏

    翻译标题摘要

    我要上传

    求助全文

  • 文章类型: Systematic Review
    目的:分析临床药师在疑似β-内酰胺类抗生素过敏时的作用及其对抗菌药物管理的影响。
    方法:我们进行了两次不同的独立书目检索。共找到35篇文章,纳入研究的最终人数为12。我们对文章进行了分析,并收集了疗效变量,安全,以及应用于怀疑对β-内酰胺类过敏的患者的评估工具的适用性。此外,分析了替代抗生素的用量和处方分布的变化.
    结果:选定的研究分析了问卷,过敏脱标签,皮内试验,和药剂师进行的口腔挑战测试。在4项有利于药物干预的研究中发现了疗效终点的显着差异。在Kwiatkowski等人的研究中。,药师干预后,手术患者使用头孢唑林的比例增加(65%vs28%;P<.01)。在一个准实验研究中,氨曲南的平均每日剂量和每1000名患者的平均治疗天数减少(21.23vs9.05,P<.01)和(8.79-4.24,P=.016),干预前和干预后,分别,增加抗生素降级(P=<0.01)。在另一项准实验研究中,限制使用抗生素的处方减少(42.5%vs17.9%,P<.01)和使用术前预防性抗生素替代头孢唑林(81.9%vs55.9%,P<0.01)在另一项研究中。其他研究表明,每位患者每次访谈的平均时间为5.2分钟。在任何研究中均未报告不良事件。
    结论:药剂师干预对疑似β-内酰胺过敏患者的评估是有效的,安全,在日常临床实践中实施是可行的。澄清过敏史的协议标准化和评估工具的开发代表了简单的筛查,以进行去标签或参考免疫变态反应服务,改善penicilins的使用并减少对二线抗生素的需求。需要更多的研究来标准化药剂师的脱敏测试。然而,尽管有这些结果,药剂师在这一领域的参与和领导是有限的,对该行业构成了未来的挑战。
    To analyze the role played by the clinical pharmacist and its impact in antibiotic stewardship facing suspected allergy to beta-lactam antibiotics.
    We performed 2 different independent bibliographic searches. A total of 35 articles were found, and the final number included in the study was 12. We analyzed the articles and collected variables of efficacy, safety, and applicability of evaluation tools applied to patients with suspected allergy to beta-lactams. Also, the variation in the consumption and prescription profile of alternative antibiotics was analyzed.
    The selected studies analyzed questionnaires, allergy delabeling, intradermal tests, and oral challenge tests performed by pharmacists. Significant differences in the efficacy endpoint were found in 4 studies in favor of pharmaceutical intervention. In the study of Kwiatkowski et al., cefazolin use increased in surgical patients after pharmacist intervention (65% vs 28%; P < .01). In a quasi-experimental study, the mean defined daily dose of aztreonam and the mean days of therapy per 1000 patients/day decreased (21.23 vs 9.05, P <.01) and (8.79-4.24, P = .016), pre- and post-intervention, respectively, increasing antibiotic de-escalations (P = < .01). In another quasi-experimental study, the prescription of restricted use antibiotics decreased (42.5% vs 17.9%, P < .01)and the use of pre-surgical prophylactic antibiotics alternative to cefazolin (81.9% vs 55.9%, P < .01)in another study. Other study showed that the mean time per interview was 5.2 min per patient. No adverse events were reported in any study.
    The pharmacist intervention in the evaluation of the patient with suspected allergy to beta-lactams is effective, safe, and feasible to implement on daily clinical practice. The standardization of protocols to clarify the history of allergies and development of evaluation tools represent simple screenings to perform delabeling or refer to the Immunoallergology service, improving penicilins use and reducing the need for second-line antibiotics. More studies are needed to standardize the desensitization tests made by pharmacists. However, despite these results, the involvement and leadership of the pharmacist in this area is limited and constitutes a future challenge for the profession.
    导出

    更多引用

    收藏

    翻译标题摘要

    我要上传

    求助全文

  • 文章类型: Systematic Review
    目的:分析临床药师在疑似β-内酰胺类抗生素过敏时的作用及其对抗菌药物管理的影响。
    方法:我们进行了两个不同的独立书目检索。共找到35篇文章,纳入研究的最终人数为12。我们对文章进行了分析,并收集了疗效变量,应用于疑似β-内酰胺类过敏患者的评估工具的安全性和适用性.此外,分析了替代抗生素的用量和处方分布的变化.
    结果:选定的研究分析了问卷,过敏脱标签,药剂师进行的皮内试验和口腔激发试验。在4项有利于药物干预的研究中发现了疗效终点的显着差异。在Kwiatkowski等人的研究中,药师干预后手术患者头孢唑林的使用增加(65vs.28%;p<0.01)。在一个准实验研究中,氨曲南的平均每日剂量和每1000名患者的平均治疗天数减少(21.23vs9.05,p<0.01)和(8.79-4.24,p=0.016),干预前和干预后,分别,增加抗生素降级(p≤0.01)。在另一项准实验研究中,限制使用抗生素的处方减少(42.5%vs.17.9%,p<0.01)和使用头孢唑啉的术前预防性抗生素(81.9%vs55.9%,p<0.01)在另一项研究中。其他研究表明,每位患者每次访谈的平均时间为5.2分钟。在任何研究中均未报告不良事件。
    结论:药剂师干预对疑似β-内酰胺过敏患者的评估是有效的,在日常临床实践中安全可行。澄清过敏史的协议标准化和评估工具的开发代表了简单的筛查,以执行去标签或参考免疫变态反应服务,改善青霉素的使用并减少对二线抗生素的需求。需要更多的研究来标准化药剂师的脱敏测试。然而,尽管有这些结果,药剂师在这一领域的参与和领导是有限的,对该行业构成了未来的挑战。
    To analyze the role played by the clinical pharmacist and its impact in antibiotic stewardship facing suspected allergy to beta-lactam antibiotics.
    We performed two different independent bibliographic searches. A total of 35 articles were found, and the final number included in the study was 12. We analysed the articles and collected variables of efficacy, safety and applicability of evaluation tools applied to patients with suspected allergy to beta-lactams. Also, the variation in the consumption and prescription profile of alternative antibiotics was analyzed.
    The selected studies analysed questionnaires, allergy delabeling, intradermal tests and oral challenge tests performed by pharmacists. Significant differences in the efficacy endpoint were found in 4 studies in favour of pharmaceutical intervention. In the study of Kwiatkowski et al, cefazolin use increased in surgical patients after pharmacist intervention (65 vs. 28%; p < 0.01). In a quasi-experimental study, the mean defined daily dose of aztreonam and the mean days of therapy per 1000 patients/day decreased (21.23 vs 9.05, p <0.01) and (8.79-4.24, p = 0.016), pre and post-intervention, respectively, increasing antibiotic de-escalations (p ≤ 0.01). In another quasi-experimental study, the prescription of restricted-use antibiotics decreased (42.5% vs. 17.9%, p < 0.01) and the use of pre-surgical prophylactic antibiotics alternative to cefazolin (81.9% vs 55.9%, p<0.01) in another study. Other study showed that the mean time per interview was 5.2 minutes per patient. No adverse events were reported in any study.
    The pharmacist intervention in the evaluation of the patient with suspected allergy to beta-lactams is effective, safe and feasible to implement on daily clinical practice. The standardization of protocols to clarify the history of allergies and development of evaluation tools represent simple screenings to perform delabelling or refer to the Immunoallergology service, improving penicilins use and reducing the need for second line antibiotics. More studies are needed to standardize the desensitization tests made by pharmacists. However, despite these results, the involvement and leadership of the pharmacist in this area is limited and constitutes a future challenge for the profession.
    导出

    更多引用

    收藏

    翻译标题摘要

    我要上传

    求助全文

  • 文章类型: Journal Article
    自由生活的线虫藏有并传播各种土壤传播的细菌病原体。无论它们是作为水生嗜肺乳杆菌的载体还是环境水库,军团病的病原体,是未知的。对德国自然(游泳湖泊)和技术(冷却塔)水栖息地的生物膜进行的调查筛选显示,线虫可以充当潜在的水库,冷却塔中嗜肺乳杆菌的载体或食草。因此,从同一冷却塔生物膜中分离出线虫物种Plectussimilis和嗜肺乳杆菌,并将其带入单氧培养物中。使用咽泵检测,检查了P.similis与不同的嗜肺乳杆菌菌株和突变体之间的潜在摄食关系,并将其与Plectussp。,从嗜肺乳杆菌阳性热源生物膜中分离出的物种。分析结果表明,嗜肺乳杆菌冷却塔分离物KV02的细菌悬浮液和上清液降低了线虫的泵送速率和摄食活性。然而,研究军团菌主要分泌蛋白ProA对抽水速率的假设负面影响的试验揭示了对线虫的相反影响,这指向物种对ProA的特定反应。为了将食物链延伸到进一步的营养级,向线虫提供了感染肺炎链球菌KV02的castellanii。饲喂嗜肺乳杆菌感染的卡氏A.castellanii时,P.similis的泵送率增加,而Plectussp.饲喂感染或未感染的A.castellanii时,抽水率相似。这项研究表明,冷却塔是肺炎杆菌和自由生活线虫共存的主要水体,是阐明该栖息地共存分类群之间营养联系的第一步。调查军团菌-线虫-变形虫的相互作用强调了变形虫作为线虫捕食者病原体的水库和传播媒介的重要性。
    Free-living nematodes harbor and disseminate various soil-borne bacterial pathogens. Whether they function as vectors or environmental reservoirs for the aquatic L. pneumophila, the causative agent of Legionnaires\' disease, is unknown. A survey screening of biofilms of natural (swimming lakes) and technical (cooling towers) water habitats in Germany revealed that nematodes can act as potential reservoirs, vectors or grazers of L. pneumophila in cooling towers. Consequently, the nematode species Plectus similis and L. pneumophila were isolated from the same cooling tower biofilm and taken into a monoxenic culture. Using pharyngeal pumping assays, potential feeding relationships between P. similis and different L. pneumophila strains and mutants were examined and compared with Plectus sp., a species isolated from a L. pneumophila-positive thermal source biofilm. The assays showed that bacterial suspensions and supernatants of the L. pneumophila cooling tower isolate KV02 decreased pumping rate and feeding activity in nematodes. However, assays investigating the hypothesized negative impact of Legionella\'s major secretory protein ProA on pumping rate revealed opposite effects on nematodes, which points to a species-specific response to ProA. To extend the food chain by a further trophic level, Acanthamoebae castellanii infected with L. pneumphila KV02 were offered to nematodes. The pumping rates of P. similis increased when fed with L. pneumophila-infected A. castellanii, while Plectus sp. pumping rates were similar when fed either infected or non-infected A. castellanii. This study revealed that cooling towers are the main water bodies where L. pneumophila and free-living nematodes coexist and is the first step in elucidating the trophic links between coexisting taxa from that habitat. Investigating the Legionella-nematode-amoebae interactions underlined the importance of amoebae as reservoirs and transmission vehicles of the pathogen for nematode predators.
    导出

    更多引用

    收藏

    翻译标题摘要

    我要上传

    求助全文

  • 文章类型: Review
    2012年,西班牙传染病和临床微生物学学会(SEIMC),医院药房(SEFH),和预防医学,公共卫生和医疗保健管理(SEMPSGS)领导了一份共识文件,其中包括在西班牙急性护理医院实施抗菌药物管理(AMS)计划(AMSP;PROA)的建议。虽然这些建议对于许多中心发展这些计划至关重要,需要指导针对特定患者人群的AMS活动的发展,以前的文件中未包括或此后显着发展的综合症或其他特定方面。本专家建议指导文件的目的是审查有关这些患者人群或环境中这些活动的可用信息,并提供有关它们的指导建议。为了这个目标,SEIMC,SEFH,SEMPSPGS,西班牙重症监护医学学会(SEMICYUC)和西班牙儿科传染病学会(SEIP)选择了一个专家小组,他们选择了不同的方面纳入文件.由于在开展活动方面缺乏高层次的证据,小组选择对不同主题的文献进行叙述性审查,这些主题的建议已达成共识。文件公开征询这些社团成员的意见和建议,小组对其进行了审查和审议。
    In 2012, The Spanish Societies of Infectious Diseases and Clinical Microbiology (SEIMC), Hospital Pharmacy (SEFH), and Preventive Medicine, Public Health and Healthcare Management (SEMPSGS) lead a consensus document including recommendations for the implementation of antimicrobial stewardship (AMS) programs (AMSP; PROA in Spanish) in acute care hospitals in Spain. While these recommendations were critical for the development of these programs in many centres, there is a need for guidance in the development of AMS activities for specific patient populations, syndromes or other specific aspects which were not included in the previous document or have developed significantly since then. The objective of this expert recommendation guidance document is to review the available information about these activities in these patient populations or circumstances, and to provide guidance recommendations about them. With this objective the SEIMC, SEFH, SEMPSPGS, the Spanish Society of Intensive Care Medicine (SEMICYUC) and the Spanish Pediatric Infectious Disease Society (SEIP) selected a panel of experts who chose the different aspects to include in the document. Because of the lack of high-level evidence in the implementation of the activities, the panel opted to perform a narrative review of the literature for the different topics for which recommendations were agreed by consensus. The document was open to public consultation for the members of these societies for their comments and suggestions, which were reviewed and considered by the panel.
    导出

    更多引用

    收藏

    翻译标题摘要

    我要上传

    求助全文

  • 文章类型: Journal Article
    背景:在急诊科(ED)中,PROA最重要的策略之一是准确诊断感染,以避免不适当的处方。我们的目标是评估尽管没有感染的客观数据但仍接受抗生素治疗的患者。
    方法:我们对接受Alcorcón大学医院ED的患者进行了一项横断面研究,其中建议通过PROA暂停使用抗生素。分析临床和流行病学特征以及30天随访以评估再入院和死亡率。
    结果:对145例患者进行分析。建议在25中暂停抗生素。其中44%诊断为尿路感染。88%的人接受了暂停建议。无患者死亡,1例再次入院。
    结论:尽管没有感染标准,但仍有很大一部分患者服用了抗生素,抗生素暂停后的临床进展是有利的。
    BACKGROUND: One of the most important strategies of PROA in the Emergency Department (ED) is the accurate diagnosis of infection to avoid inappropriate prescription. Our objective is to evaluate patients who receive antibiotics despite not having objective data of infection.
    METHODS: We carried out a cross-sectional study of patients admitted to the ED of the Hospital Universitario Fundación Alcorcón in which it was recommended to suspend the antibiotic through the PROA. Clinical and epidemiological characteristics and 30-day follow-up were analyzed to assess readmissions and mortality.
    RESULTS: 145 patients were analyzed. It was recommended to suspend the antibiotic in 25. 44% of them had a diagnosis of urinary infection. The suspension recommendation was accepted by 88%. No patient died and one was readmitted.
    CONCLUSIONS: An important percentage of patients are prescribed antibiotics despite not having infection criteria, the clinical evolution after suspension of antibiotics was favorable.
    导出

    更多引用

    收藏

    翻译标题摘要

    我要上传

    求助全文

  • 文章类型: Journal Article
    已预测为γ-谷氨酰磷酸还原酶ProA,可催化谷氨酸形成脯氨酸的第二个反应。这里,我们通过实验证明,proA突变体是脯氨酸营养缺陷型,无法在基本培养基中生长,和补充脯氨酸,但不是谷氨酸,完全恢复了减少的增长,确认ProA负责从茄尾R.的谷氨酸生物合成脯氨酸。ProA先前被确定为调节三型分泌系统(T3SS)基因表达的候选物之一,青枯菌的基本致病性决定因素之一。补充脯氨酸在体外和植物中均显着增强了T3SS的表达,表明脯氨酸是T3SS表达的新型诱导物。即使在补充脯氨酸的条件下,proA的缺失也会严重损害体外和植物中的T3SS表达,表明ProA在促进T3SS基因的表达方面除了脯氨酸的生物合成外还起着其他作用。进一步揭示ProA参与T3SS表达是通过PrhG-HrpB途径介导的。proA突变体和野生型菌株都在烟草叶片的细胞间隙中生长,虽然它们侵入和定植烟草木质部血管的能力受到了严重损害,proA突变体成功入侵木质部血管的时间约为1天,并且比野生型菌株在木质部血管中增殖到最大密度的数量低约一个数量级。因此,它导致proA突变体对宿主烟草植物的毒力大大降低。proA突变体入侵和定植木质部血管的能力受损并不是由于根际土壤或植物内部的脯氨酸不足所致。全部放在一起,这些结果扩展了对ProA生物学功能的理解以及T3SS的复杂调节和茄尾R.
    Ralstonia solanacearum RSc2741 has been predicted as a gamma-glutamyl phosphate reductase ProA catalyzing the second reaction of proline formation from glutamate. Here, we experimentally demonstrated that proA mutants were proline auxotrophs that failed to grow in a minimal medium, and supplementary proline, but not glutamate, fully restored the diminished growth, confirming that ProA is responsible for the biosynthesis of proline from glutamate in R. solanacearum. ProA was previously identified as one of the candidates regulating the expression of genes for type three secretion system (T3SS), one of the essential pathogenicity determinants of R. solanacearum. Supplementary proline significantly enhanced the T3SS expression both in vitro and in planta, indicating that proline is a novel inducer of the T3SS expression. Deletion of proA substantially impaired the T3SS expression both in vitro and in planta even under proline-supplemented conditions, indicating that ProA plays additional roles apart from proline biosynthesis in promoting the expression of the T3SS genes. It was further revealed that the involvement of ProA in the T3SS expression was mediated through the pathway of PrhG-HrpB. Both the proA mutants and the wild-type strain grew in the intercellular spaces of tobacco leaves, while their ability to invade and colonize tobacco xylem vessels was substantially impaired, which was about a 1-day delay for proA mutants to successfully invade xylem vessels and was about one order of magnitude less than the wild-type strain to proliferate to the maximum densities in xylem vessels. It thus resulted in substantially impaired virulence of proA mutants toward host tobacco plants. The impaired abilities of proA mutants to invade and colonize xylem vessels were not due to possible proline insufficiency in the rhizosphere soil or inside the plants. All taken together, these results extend novel insights into the understanding of the biological function of ProA and sophisticated regulation of the T3SS and pathogenicity in R. solanacearum.
    导出

    更多引用

    收藏

    翻译标题摘要

    我要上传

       PDF(Pubmed)

  • 文章类型: Journal Article
    环境细菌嗜肺军团菌是各种原生动物宿主的细胞内病原体,能够引起军团病,人类的严重肺炎。通过编码多种毒力因子,感染因子具有几种策略来操纵其宿主细胞和逃避免疫检测。在本研究中,我们证明了嗜肺乳杆菌锌金属蛋白酶ProA作为鞭毛蛋白介导的TLR5刺激和随后的促炎NF-κB途径激活的调节剂。我们发现ProA能够直接降解免疫原性FlaA单体,但不能降解细菌鞭毛的聚合物形式。这些结果表明蛋白酶在拮抗免疫刺激中的作用,这在HEK-BlueTMhTLR5检测测定中进一步证实。添加纯化的蛋白质,嗜肺乳杆菌突变菌株的细菌悬浮液以及人肺组织外植体感染该报告细胞系的上清液表明,ProA通过FlaA降解特异性降低TLR5反应。最后,锌金属蛋白酶ProA可作为外源鞭毛蛋白的强大调节剂,并可能通过促进免疫逃避为哺乳动物宿主中的嗜肺乳杆菌增殖创造了重要优势。
    The environmental bacterium Legionella pneumophila is an intracellular pathogen of various protozoan hosts and able to cause Legionnaires\' disease, a severe pneumonia in humans. By encoding a wide selection of virulence factors, the infectious agent possesses several strategies to manipulate its host cells and evade immune detection. In the present study, we demonstrate that the L. pneumophila zinc metalloprotease ProA functions as a modulator of flagellin-mediated TLR5 stimulation and subsequent activation of the pro-inflammatory NF-κB pathway. We found ProA to be capable of directly degrading immunogenic FlaA monomers but not the polymeric form of bacterial flagella. These results indicate a role of the protease in antagonizing immune stimulation, which was further substantiated in HEK-BlueTM hTLR5 Detection assays. Addition of purified proteins, bacterial suspensions of L. pneumophila mutant strains as well as supernatants of human lung tissue explant infection to this reporter cell line demonstrated that ProA specifically decreases the TLR5 response via FlaA degradation. Conclusively, the zinc metalloprotease ProA serves as a powerful regulator of exogenous flagellin and presumably creates an important advantage for L. pneumophila proliferation in mammalian hosts by promoting immune evasion.
    导出

    更多引用

    收藏

    翻译标题摘要

    我要上传

    求助全文

  • 文章类型: Journal Article
    The evolution of novel enzymes has fueled the diversification of life on earth for billions of years. Insights into events that set the stage for the evolution of a new enzyme can be obtained from ancestral reconstruction and laboratory evolution. Ancestral reconstruction can reveal the emergence of a promiscuous activity in a pre-existing protein and the impact of subsequent mutations that enhance a new activity. Laboratory evolution provides a more holistic view by revealing mutations elsewhere in the genome that indirectly enhance the level of a newly important enzymatic activity. This review will highlight recent studies that probe the early stages of the evolution of a new enzyme from these complementary points of view.
    导出

    更多引用

    收藏

    翻译标题摘要

    我要上传

       PDF(Sci-hub)

       PDF(Pubmed)

公众号