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Role of VapBC4 toxin-antitoxin system of Sulfolobus acidocaldarius in heat stress adaptation. Sulfolobus acidocaldarius 的 VapBC4 毒素-抗毒素系统在热胁迫适应中的作用。
IF 5.1 1区 生物学 Q1 MICROBIOLOGY Pub Date : 2024-11-13 DOI: 10.1128/mbio.02753-24
Arghya Bhowmick, Alejandra Recalde, Chandrima Bhattacharyya, Ankita Banerjee, Jagriti Das, Ulises E Rodriguez-Cruz, Sonja-Verena Albers, Abhrajyoti Ghosh
<p><p>Toxin-antitoxin (TA) systems are important for stress adaptation in prokaryotes, including persistence, antibiotic resistance, pathogenicity, and biofilm formation. Toxins can cause cell death, reversible growth stasis, and direct inhibition of crucial cellular processes through various mechanisms, while antitoxins neutralize the effects of toxins. In bacteria, these systems have been studied in detail, whereas their function in archaea remains elusive. During heat stress, the thermoacidophilic archaeon <i>Sulfolobus acidocaldarius</i> exhibited an increase in the expression of several bicistronic type II <i>vapBC</i> TA systems, with the highest expression observed in the <i>vapBC4</i> system. In the current study, we performed a comprehensive biochemical characterization of the VapBC4 TA system, establishing it as a bonafide type II toxin-antitoxin system. The VapC4 toxin is shown to have high-temperature catalyzed RNase activity specific for mRNA and rRNA, while the VapB4 antitoxin inhibits the toxic activity of VapC4 by interacting with it. VapC4 toxin expression led to heat-induced persister-like cell formation, allowing the cell to cope with the stress. Furthermore, this study explored the impact of <i>vapBC4</i> deletion on biofilm formation, whereby deletion of <i>vapC4</i> led to increased biofilm formation, suggesting its role in regulating biofilm formation. Thus, during heat stress, the liberated VapC4 toxin in cells could potentially signal a preference for persister cell formation over biofilm growth. Thus, our findings shed light on the diverse roles of the VapC4 toxin in inhibiting translation, inducing persister cell formation, and regulating biofilm formation in <i>S. acidocaldarius</i>, enhancing our understanding of TA systems in archaea.</p><p><strong>Importance: </strong>This research enhances our knowledge of toxin-antitoxin (TA) systems in archaea, specifically in the thermoacidophilic archaeon <i>Sulfolobus acidocaldarius</i>. TA systems are widespread in both bacterial and archaeal genomes, indicating their evolutionary importance. However, their exact functions in archaeal cellular physiology are still not well understood. This study sheds light on the complex roles of TA systems and their critical involvement in archaeal stress adaptation, including persistence and biofilm formation. By focusing on <i>S. acidocaldarius</i>, which lives in habitats with fluctuating temperatures that can reach up to 90°C, the study reveals the unique challenges and survival mechanisms of this organism. The detailed biochemical analysis of the VapBC4 TA system, and its crucial role during heat stress, provides insights into how extremophiles can survive in harsh conditions. The findings of this study show the various functions of the VapC4 toxin, including inhibiting translation, inducing persister-like cell formation, and regulating biofilm formation. This knowledge improves our understanding of TA systems in thermoacidophiles and
毒素-抗毒素(TA)系统对原核生物的应激适应非常重要,包括持久性、抗生素耐药性、致病性和生物膜的形成。毒素可导致细胞死亡、可逆的生长停滞,并通过各种机制直接抑制关键的细胞过程,而抗毒素则能中和毒素的作用。在细菌中,人们对这些系统进行了详细研究,而在古细菌中,这些系统的功能仍然难以捉摸。在热应激期间,嗜热古菌 Sulfolobus acidocaldarius 表现出几种双单子型 II vapBC TA 系统的表达增加,其中 vapBC4 系统的表达量最高。在本研究中,我们对 VapBC4 TA 系统进行了全面的生化鉴定,将其确定为真正的 II 型毒素-抗毒素系统。研究表明,VapC4毒素具有高温催化的RNase活性,专一于mRNA和rRNA,而VapB4抗毒素则通过与VapC4相互作用来抑制其毒性活性。VapC4 毒素的表达导致了热诱导的类宿主细胞的形成,使细胞能够应对压力。此外,本研究还探讨了缺失 vapBC4 对生物膜形成的影响,缺失 vapC4 会导致生物膜形成增加,表明其在调节生物膜形成中的作用。因此,在热应激过程中,细胞中释放的 VapC4 毒素可能会发出一种信号,即与生物膜生长相比,更倾向于形成固着细胞。因此,我们的发现揭示了VapC4毒素在酸性链球菌中抑制翻译、诱导宿主细胞形成和调节生物膜形成的不同作用,加深了我们对古细菌TA系统的了解:这项研究增进了我们对古细菌毒素-抗毒素(TA)系统的了解,特别是对嗜热古细菌 Sulfolobus acidocaldarius 的了解。TA系统广泛存在于细菌和古细菌的基因组中,这表明了它们在进化过程中的重要性。然而,它们在古细菌细胞生理学中的确切功能仍不甚明了。本研究揭示了 TA 系统的复杂作用及其在古细菌应激适应(包括持久性和生物膜形成)中的关键作用。通过重点研究生活在温度波动高达 90°C 的生境中的 S. acidocaldarius,该研究揭示了这种生物所面临的独特挑战和生存机制。通过对 VapBC4 TA 系统的详细生化分析及其在热应激过程中的关键作用,我们深入了解了嗜极生物如何在恶劣条件下生存。这项研究的结果表明了VapC4毒素的各种功能,包括抑制翻译、诱导类宿主细胞的形成以及调节生物膜的形成。这些知识增进了我们对嗜热菌TA系统的了解,对了解微生物如何适应极端环境具有更广泛的意义。
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引用次数: 0
Phosphorylation of Ser711 residue in the hypervariable region of zoonotic genotype 3 hepatitis E virus is important for virus replication. 人畜共患基因型 3 戊型肝炎病毒超变异区中的 Ser711 残基磷酸化对病毒复制非常重要。
IF 5.1 1区 生物学 Q1 MICROBIOLOGY Pub Date : 2024-11-13 Epub Date: 2024-10-08 DOI: 10.1128/mbio.02635-24
Bo Wang, Sakthivel Subramaniam, Debin Tian, Hassan M Mahsoub, C Lynn Heffron, Xiang-Jin Meng

Hepatitis E virus (HEV) is distinct from other hepatotropic viruses because it is zoonotic. HEV-1 and HEV-2 exclusively infect humans, whereas HEV-3 and HEV-4 are zoonotic. However, the viral and/or host factors responsible for cross-species HEV transmission remain elusive. The hypervariable region (HVR) in HEV is extremely heterogenetic and is implicated in HEV adaptation. Here, we investigated the potential role of Serine phosphorylation in the HVR in HEV replication. We first analyzed HVR sequences across different HEV genotypes and identified a unique region at the N-terminus of the HVR, which is variable in the human-exclusive HEV genotypes but relatively conserved in zoonotic HEV genotypes. Using predictive tools, we identified four potential phosphorylation sites that are highly conserved in zoonotic HEV-3 and HEV-4 genomes but absent in human-exclusive HEV-1 strains. To explore the functional significance of these putative phosphorylation sites, we introduced mutations into the HEV-3 infectious clone and indicator replicon, replacing each Serine residue individually with alanine or aspartic acid, and assessed the impact of these substitutions on HEV-3 replication. We found that the phospho-blatant S711A mutant significantly reduced virus replication, whereas the phospho-mimetic S711D mutant modestly reduced virus replication. Conversely, mutations in the other three Serine residues did not significantly affect HEV-3 replication. Furthermore, we demonstrated that Ser711 phosphorylation did not alter host cell tropism of zoonotic HEV-3. In conclusion, our results showed that potential phosphorylation of the Ser711 residue significantly affects HEV-3 replication in vitro, providing new insights into the potential mechanisms of zoonotic HEV transmission.IMPORTANCEHEV is an important zoonotic pathogen, causing both acute and chronic hepatitis E and extrahepatic manifestation of diseases, such as neurological sequelae. The zoonotic HEV-3 is linked to chronic infection and neurological diseases. The specific viral and/or host factors facilitating cross-species HEV infection are unknown. The intrinsically disordered HVR in ORF1 is crucial for viral fitness and adaptation, both in vitro and in vivo. We hypothesized that phosphorylation of Serine residues in the HVR of zoonotic HEV by unknown host cellular kinases is associated with cross-species HEV transmission. In this study, we identified a conserved region within the HVR of zoonotic HEV strains but absent in the human-exclusive HEV-1 and HEV-2. We elucidated the important role of phosphorylation at the Ser711 residue in zoonotic HEV-3 replication, without altering the host cell tropism. These findings contribute to our understanding the mechanisms of cross-species HEV transmission.

戊型肝炎病毒(HEV)不同于其他肝病病毒,因为它是人畜共患病毒。HEV-1 和 HEV-2 只感染人类,而 HEV-3 和 HEV-4 则是人畜共患病毒。然而,导致 HEV 跨物种传播的病毒和/或宿主因素仍然难以捉摸。HEV 中的超变异区(HVR)具有极强的异质性,与 HEV 的适应性有关。在这里,我们研究了 HVR 中丝氨酸磷酸化在 HEV 复制中的潜在作用。我们首先分析了不同 HEV 基因型的 HVR 序列,发现了 HVR N 端的一个独特区域,该区域在人类专属的 HEV 基因型中可变,但在人畜共患的 HEV 基因型中相对保守。利用预测工具,我们确定了四个潜在的磷酸化位点,它们在人畜共患的 HEV-3 和 HEV-4 基因组中高度保守,但在人类专属的 HEV-1 株系中却不存在。为了探索这些潜在磷酸化位点的功能意义,我们在 HEV-3 感染性克隆和指示性复制子中引入了突变,用丙氨酸或天冬氨酸分别取代了每个丝氨酸残基,并评估了这些取代对 HEV-3 复制的影响。我们发现,磷酸化空白的 S711A 突变体能显著减少病毒复制,而磷酸化拟态的 S711D 突变体则能适度减少病毒复制。相反,其他三个丝氨酸残基的突变对 HEV-3 的复制没有明显影响。此外,我们还证明 Ser711 磷酸化不会改变人畜共患病 HEV-3 的宿主细胞滋养性。总之,我们的研究结果表明,Ser711残基的潜在磷酸化会明显影响HEV-3在体外的复制,从而为人畜共患的HEV传播的潜在机制提供了新的见解。人畜共患病 HEV-3 与慢性感染和神经系统疾病有关。促进 HEV 跨物种感染的特定病毒和/或宿主因素尚不清楚。ORF1 中的内在紊乱 HVR 对病毒在体外和体内的适应性和适应性至关重要。我们假设,人畜共患病 HEV HVR 中丝氨酸残基被未知宿主细胞激酶磷酸化与 HEV 的跨物种传播有关。在这项研究中,我们在人畜共患 HEV 株系的 HVR 中发现了一个保守区域,但在人类独有的 HEV-1 和 HEV-2 中却不存在。我们阐明了Ser711残基的磷酸化在人畜共患HEV-3复制中的重要作用,而不会改变宿主细胞的滋养性。这些发现有助于我们了解 HEV 的跨物种传播机制。
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引用次数: 0
Cryptococcus neoformans infections: aspartyl protease potential to improve outcome in susceptible hosts. 新型隐球菌感染:天冬氨酰蛋白酶改善易感宿主预后的潜力。
IF 5.1 1区 生物学 Q1 MICROBIOLOGY Pub Date : 2024-11-13 Epub Date: 2024-10-23 DOI: 10.1128/mbio.02733-24
Frédérique Vernel-Pauillac, Christine Laurent-Winter, Laurence Fiette, Guilhem Janbon, Vishukumar Aimanianda, Françoise Dromer

Though a confined or a broad population is exposed respectively to endemic or pandemic infections, in the same environment, some individuals resist the development of infections. The attributed reason is the inheritance of a set of immune system genes that can efficiently deal with the pathogens. In this study, we show how outbred mice differentially respond to Cryptococcus neoformans, a fungal pathogen, and the mechanism through which the surviving mice mount a protective immune defense. We identified that those mice developing antibodies specifically against Pep1p, an aspartic protease secreted by C. neoformans, had significantly improved survival. Vaccination (either prophylactic or therapeutic) with a recombinant Pep1p significantly increased the survival of the mice by decreasing the fungal load and stimulating a protective immune response. Passive immunization of C. neoformans-infected mice with monoclonal antibodies developed against Pep1p also improves the survival of the mice by increasing phagocytosis of C. neoformans and decreasing the multiplication of this fungus. Together, these data demonstrate the prophylactic and therapeutic potentials of the C. neoformans antigenic protein Pep1p or Pep1p-specific antibodies against this fungal infection. Also, this study suggests that the immunological interaction and thereby the responses developed against a pathogen guide the hosts to behave differentially against microbial pathogenicity.

Importance: Vaccination and immunotherapies against fungal pathogens still remain a challenge. Here, we show using an in vivo model based on outbred mice that development of antibodies against Pep1p, an antigenic protein of the fungal pathogen Cryptococcus neoformans, confers resistance to this fungal infection. In support of this observation, prophylactic or therapeutic immunization of the mice with recombinant Pep1p could improve their survival when infected with a lethal dose of C. neoformans. Moreover, passive therapy with monoclonal anti-Pep1p antibodies also enhanced survival of the mice from C. neoformans infection. The associated antifungal mechanisms were mounting of a protective immune response and the development of fungal specific antibodies that decrease the fungal burden due to an increase in their phagocytosis and/or inhibit the fungal multiplication. Together, our study demonstrates (a) the mode of host-fungal interaction and the immune response developed thereby play a crucial role in developing resistance against C. neoformans; (b) Pep1p, an aspartic protease as well as an antigenic protein secreted by C. neoformans, can be exploited for vaccination (both prophylactic and therapeutic) or immunotherapy to improve the host defense during this fungal infection.

尽管一个封闭或广泛的人群分别暴露于地方性或大流行性感染,但在相同的环境中,一些个体会抵御感染的发展。究其原因,是遗传了一套能有效对付病原体的免疫系统基因。在这项研究中,我们展示了近亲繁殖的小鼠如何对真菌病原体新生隐球菌做出不同的反应,以及存活下来的小鼠是通过什么机制建立起保护性免疫防御的。我们发现,对新隐球菌分泌的天冬氨酸蛋白酶 Pep1p 产生特异性抗体的小鼠存活率显著提高。接种重组 Pep1p 疫苗(预防性或治疗性)可降低真菌负荷并激发保护性免疫反应,从而显著提高小鼠的存活率。用针对 Pep1p 开发的单克隆抗体被动免疫感染 C. neoformans 的小鼠,也能通过增加对 C. neoformans 的吞噬作用和减少这种真菌的繁殖来提高小鼠的存活率。这些数据共同证明了新变形杆菌抗原蛋白 Pep1p 或 Pep1p 特异性抗体对这种真菌感染的预防和治疗潜力。此外,这项研究还表明,免疫相互作用以及由此产生的针对病原体的反应会引导宿主对微生物的致病性采取不同的行为:重要意义:针对真菌病原体的疫苗接种和免疫疗法仍然是一项挑战。在这里,我们利用一个基于外育小鼠的体内模型表明,针对真菌病原体新生隐球菌的抗原蛋白 Pep1p 产生抗体,可增强对这种真菌感染的抵抗力。为了证实这一观点,当小鼠感染致命剂量的新生隐球菌时,用重组 Pep1p 对其进行预防性或治疗性免疫可提高其存活率。此外,使用单克隆抗 Pep1p 抗体进行被动治疗也能提高小鼠在感染新酵母菌后的存活率。与此相关的抗真菌机制是保护性免疫反应的启动和真菌特异性抗体的产生,这些抗体可通过增加吞噬作用和/或抑制真菌繁殖来减少真菌负担。总之,我们的研究表明:(a)宿主与真菌的相互作用模式以及由此产生的免疫反应在形成对新霉菌的抵抗力方面起着至关重要的作用;(b)Pep1p 是一种天冬氨酸蛋白酶,也是新霉菌分泌的一种抗原蛋白,可用于疫苗接种(预防性和治疗性)或免疫疗法,以提高宿主在真菌感染期间的防御能力。
{"title":"<i>Cryptococcus neoformans</i> infections: aspartyl protease potential to improve outcome in susceptible hosts.","authors":"Frédérique Vernel-Pauillac, Christine Laurent-Winter, Laurence Fiette, Guilhem Janbon, Vishukumar Aimanianda, Françoise Dromer","doi":"10.1128/mbio.02733-24","DOIUrl":"10.1128/mbio.02733-24","url":null,"abstract":"<p><p>Though a confined or a broad population is exposed respectively to endemic or pandemic infections, in the same environment, some individuals resist the development of infections. The attributed reason is the inheritance of a set of immune system genes that can efficiently deal with the pathogens. In this study, we show how outbred mice differentially respond to <i>Cryptococcus neoformans,</i> a fungal pathogen, and the mechanism through which the surviving mice mount a protective immune defense. We identified that those mice developing antibodies specifically against Pep1p, an aspartic protease secreted by <i>C. neoformans</i>, had significantly improved survival. Vaccination (either prophylactic or therapeutic) with a recombinant Pep1p significantly increased the survival of the mice by decreasing the fungal load and stimulating a protective immune response. Passive immunization of <i>C. neoformans-</i>infected mice with monoclonal antibodies developed against Pep1p also improves the survival of the mice by increasing phagocytosis of <i>C. neoformans</i> and decreasing the multiplication of this fungus. Together, these data demonstrate the prophylactic and therapeutic potentials of the <i>C. neoformans</i> antigenic protein Pep1p or Pep1p-specific antibodies against this fungal infection. Also, this study suggests that the immunological interaction and thereby the responses developed against a pathogen guide the hosts to behave differentially against microbial pathogenicity.</p><p><strong>Importance: </strong>Vaccination and immunotherapies against fungal pathogens still remain a challenge. Here, we show using an <i>in vivo</i> model based on outbred mice that development of antibodies against Pep1p, an antigenic protein of the fungal pathogen <i>Cryptococcus neoformans</i>, confers resistance to this fungal infection. In support of this observation, prophylactic or therapeutic immunization of the mice with recombinant Pep1p could improve their survival when infected with a lethal dose of <i>C. neoformans</i>. Moreover, passive therapy with monoclonal anti-Pep1p antibodies also enhanced survival of the mice from <i>C. neoformans</i> infection. The associated antifungal mechanisms were mounting of a protective immune response and the development of fungal specific antibodies that decrease the fungal burden due to an increase in their phagocytosis and/or inhibit the fungal multiplication. Together, our study demonstrates (a) the mode of host-fungal interaction and the immune response developed thereby play a crucial role in developing resistance against <i>C. neoformans</i>; (b) Pep1p, an aspartic protease as well as an antigenic protein secreted by <i>C. neoformans</i>, can be exploited for vaccination (both prophylactic and therapeutic) or immunotherapy to improve the host defense during this fungal infection.</p>","PeriodicalId":18315,"journal":{"name":"mBio","volume":" ","pages":"e0273324"},"PeriodicalIF":5.1,"publicationDate":"2024-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11559057/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142503520","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Metal availability shapes early life microbial ecology and community succession. 金属供应影响生命早期微生物生态学和群落演替。
IF 5.1 1区 生物学 Q1 MICROBIOLOGY Pub Date : 2024-11-13 Epub Date: 2024-10-23 DOI: 10.1128/mbio.01534-24
Joshua Soto Ocaña, Elliot S Friedman, Orlaith Keenan, Nile U Bayard, Eileen Ford, Ceylan Tanes, Matthew J Munneke, William N Beavers, Eric P Skaar, Kyle Bittinger, Babette S Zemel, Gary D Wu, Joseph P Zackular

The gut microbiota plays a critical role in human health and disease. Microbial community assembly and succession early in life are influenced by numerous factors. In turn, assembly of this microbial community is known to influence the host, including immune system development, and has been linked to outcomes later in life. To date, the role of host-mediated nutritional immunity and metal availability in shaping microbial community assembly and succession early in life has not been explored in depth. Using a human infant cohort, we show that the metal-chelating protein calprotectin is highly abundant in infants. Taxa previously shown to be successful early colonizers of the infant gut, such as Enterococcus, Enterobacteriaceae, and Bacteroides, are highly resistant to experimental metal starvation in culture. Lactobacillus, meanwhile, is highly susceptible to metal restriction, pointing to a possible mechanism by which host-mediated metal limitation shapes the fitness of early colonizing taxa in the infant gut. We further demonstrate that formula-fed infants harbor markedly higher levels of metals in their gastrointestinal tract compared to breastfed infants. Formula-fed infants with high levels of metals harbor distinct microbial communities compared to breastfed infants, with higher levels of Enterococcus, Enterobacter, and Klebsiella, taxa which show increased resistance to the toxic effects of high metal concentrations. These data highlight a new paradigm in microbial community assembly and suggest an unappreciated role for nutritional immunity and dietary metals in shaping the earliest colonization events of the microbiota.IMPORTANCEEarly life represents a critical window for microbial colonization of the human gastrointestinal tract. Surprisingly, we still know little about the rules that govern the successful colonization of infants and the factors that shape the success of early life microbial colonizers. In this study, we report that metal availability is an important factor in the assembly and succession of the early life microbiota. We show that the host-derived metal-chelating protein, calprotectin, is highly abundant in infants and successful early life colonizers can overcome metal restriction. We further demonstrate that feeding modality (breastmilk vs formula) markedly impacts metal levels in the gut, potentially influencing microbial community succession. Our work suggests that metals, a previously unexplored aspect of early life ecology, may play a critical role in shaping the early events of microbiota assembly in infants.

肠道微生物群对人类的健康和疾病起着至关重要的作用。生命早期微生物群落的组合和演替受到多种因素的影响。反过来,已知这种微生物群落的集结会影响宿主,包括免疫系统的发育,并与以后的生活结果有关。迄今为止,还没有深入研究过宿主介导的营养免疫和金属可用性在形成生命早期微生物群落组合和演替中的作用。通过人类婴儿队列,我们发现金属螯合蛋白钙黏蛋白在婴儿中含量很高。以前被证明是婴儿肠道早期成功定殖者的类群,如肠球菌属、肠杆菌科和乳杆菌属,在培养过程中对实验性金属饥饿具有很强的抵抗力。而乳酸杆菌则极易受金属限制的影响,这表明宿主介导的金属限制可能是影响婴儿肠道早期定殖类群适应性的一种机制。我们进一步证明,与母乳喂养的婴儿相比,配方奶喂养的婴儿胃肠道中的金属含量明显更高。与母乳喂养婴儿相比,金属含量高的配方奶喂养婴儿的微生物群落与母乳喂养婴儿截然不同,其中肠球菌、肠杆菌和克雷伯氏菌含量较高,这些类群对高浓度金属的毒性作用具有更强的抵抗力。这些数据凸显了微生物群落组合的新模式,并表明营养免疫和膳食金属在塑造微生物群最早定殖事件中发挥着未被重视的作用。 重要意义生命早期是微生物定殖人体胃肠道的关键窗口期。令人惊讶的是,我们对婴儿成功定植的规则以及影响生命早期微生物定植者成功的因素仍然知之甚少。在这项研究中,我们发现金属的可用性是生命早期微生物群集结和演替的一个重要因素。我们的研究表明,源自宿主的金属螯合蛋白--钙保护蛋白在婴儿体内含量很高,成功的生命早期定殖者可以克服金属限制。我们进一步证明,喂养方式(母乳与配方奶)会明显影响肠道中的金属含量,从而可能影响微生物群落的演替。我们的研究表明,金属是生命早期生态学中一个以前未被探索的方面,它可能在婴儿微生物群的早期形成过程中发挥关键作用。
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引用次数: 0
Characterization and functional analysis of Toxoplasma Golgi-associated proteins identified by proximity labeling. 通过近距离标记鉴定的弓形虫高尔基相关蛋白的特征和功能分析。
IF 5.1 1区 生物学 Q1 MICROBIOLOGY Pub Date : 2024-11-13 Epub Date: 2024-09-30 DOI: 10.1128/mbio.02380-24
Rebecca R Pasquarelli, Justin J Quan, Emily S Cheng, Vivian Yang, Timmie A Britton, Jihui Sha, James A Wohlschlegel, Peter J Bradley

Toxoplasma gondii possesses a highly polarized secretory pathway that contains both broadly conserved eukaryotic organelles and unique apicomplexan organelles, which play essential roles in the parasite's lytic cycle. As in other eukaryotes, the T. gondii Golgi apparatus sorts and modifies proteins prior to their distribution to downstream organelles. Many of the typical trafficking factors found involved in these processes are missing from apicomplexan genomes, suggesting that these parasites have evolved unique proteins to fill these roles. Here, we identify a Golgi-localizing protein (ULP1), which is structurally similar to the eukaryotic trafficking factor p115/Uso1. We demonstrate that depletion of ULP1 leads to a dramatic reduction in parasite fitness that is the result of defects in microneme secretion, invasion, replication, and egress. Using ULP1 as bait for TurboID proximity labeling and immunoprecipitation, we identify 11 more Golgi-associated proteins and demonstrate that ULP1 interacts with the T. gondii-conserved oligomeric Golgi (COG) complex. These proteins include both conserved trafficking factors and parasite-specific proteins. Using a conditional knockdown approach, we assess the effect of each of these 11 proteins on parasite fitness. Together, this work reveals a diverse set of T. gondii Golgi-associated proteins that play distinct roles in the secretory pathway. As several of these proteins are absent outside of the Apicomplexa, they represent potential targets for the development of novel therapeutics against these parasites.

Importance: Apicomplexan parasites such as Toxoplasma gondii infect a large percentage of the world's population and cause substantial human disease. These widespread pathogens use specialized secretory organelles to infect their host cells, modulate host cell functions, and cause disease. While the functions of the secretory organelles are now better understood, the Golgi apparatus of the parasite remains largely unexplored, particularly regarding parasite-specific innovations that may help direct traffic intracellularly. In this work, we characterize ULP1, a protein that is unique to parasites but shares structural similarity to the eukaryotic trafficking factor p115/Uso1. We show that ULP1 plays an important role in parasite fitness and demonstrate that it interacts with the conserved oligomeric Golgi (COG) complex. We then use ULP1 proximity labeling to identify 11 additional Golgi-associated proteins, which we functionally analyze via conditional knockdown. This work expands our knowledge of the Toxoplasma Golgi apparatus and identifies potential targets for therapeutic intervention.

弓形虫拥有一条高度极化的分泌途径,其中既包含广泛保守的真核细胞器,也包含独特的 apicomplexan 细胞器,它们在寄生虫的裂解循环中发挥着重要作用。与其他真核生物一样,淋病双球菌高尔基体在将蛋白质分配到下游细胞器之前也会对其进行分类和修饰。这些过程中发现的许多典型的转运因子在 apicomplexan 基因组中并不存在,这表明这些寄生虫已经进化出了独特的蛋白质来扮演这些角色。在这里,我们发现了一种高尔基定位蛋白(ULP1),它在结构上类似于真核生物的转运因子 p115/Uso1。我们证明,耗尽 ULP1 会导致寄生虫的适应性急剧下降,而这是微粒分泌、入侵、复制和排出缺陷的结果。利用 ULP1 作为 TurboID 近距离标记和免疫沉淀的诱饵,我们又鉴定出 11 种高尔基相关蛋白,并证明 ULP1 与淋球菌保守寡聚高尔基复合体(COG)相互作用。这些蛋白包括保守的贩运因子和寄生虫特异性蛋白。利用条件性基因敲除方法,我们评估了这 11 种蛋白质对寄生虫适应性的影响。总之,这项研究揭示了在分泌途径中发挥不同作用的各种淋球菌高尔基相关蛋白。由于这些蛋白中有几种在表皮复合寄生虫之外并不存在,因此它们是开发针对这些寄生虫的新型疗法的潜在靶标:弓形虫等表皮复合寄生虫感染了世界上很大一部分人口,并导致大量人类疾病。这些广泛传播的病原体利用专门的分泌细胞器感染宿主细胞、调节宿主细胞功能并导致疾病。虽然现在人们对分泌细胞器的功能有了更深入的了解,但寄生虫的高尔基体在很大程度上仍未被探索,尤其是关于寄生虫特异性创新的研究,这些创新可能有助于引导细胞内的交通。在这项研究中,我们对 ULP1 进行了表征,这是一种寄生虫特有的蛋白质,但在结构上与真核生物运输因子 p115/Uso1 相似。我们发现 ULP1 在寄生虫的适应性方面发挥着重要作用,并证明它能与保守的寡聚高尔基复合体(COG)相互作用。然后,我们利用 ULP1 的近似标记鉴定了另外 11 个高尔基相关蛋白,并通过条件性敲除对其进行了功能分析。这项工作拓展了我们对弓形虫高尔基体的认识,并确定了潜在的治疗干预目标。
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引用次数: 0
Novel isolates expand the physiological diversity of Prochlorococcus and illuminate its macroevolution. 新的分离物扩大了原绿球藻的生理多样性,并揭示了其宏观进化过程。
IF 5.1 1区 生物学 Q1 MICROBIOLOGY Pub Date : 2024-11-13 Epub Date: 2024-10-18 DOI: 10.1128/mbio.03497-23
Jamie W Becker, Shaul Pollak, Jessie W Berta-Thompson, Kevin W Becker, Rogier Braakman, Keven D Dooley, Thomas Hackl, Allison Coe, Aldo Arellano, Kristen N LeGault, Paul M Berube, Steven J Biller, Andrés Cubillos-Ruiz, Benjamin A S Van Mooy, Sallie W Chisholm
<p><p><i>Prochlorococcus</i> is a diverse picocyanobacterial genus and the most abundant phototroph on Earth. Its photosynthetic diversity divides it into high-light (HL)- or low-light (LL)-adapted groups representing broad phylogenetic grades-each composed of several monophyletic clades. Here, we physiologically characterize four new <i>Prochlorococcus</i> strains isolated from below the deep chlorophyll maximum in the North Pacific Ocean. We combine these physiological properties with genomic analyses to explore the evolution of photosynthetic antennae and discuss potential macroevolutionary implications. The isolates belong to deeply branching low-light-adapted clades that have no other cultivated representatives and display some unusual characteristics. For example, despite its otherwise low-light-adapted physiological characteristics, strain MIT1223 has low chl <i>b<sub>2</sub></i> content similar to high-light-adapted strains. Isolate genomes revealed that each strain contains a unique arsenal of pigment biosynthesis and binding alleles that have been horizontally acquired, contributing to the observed physiological diversity. Comparative genomic analysis of all picocyanobacteria reveals that Pcb, the major pigment carrying protein in <i>Prochlorococcus</i>, greatly increased in copy number and diversity per genome along a branch that coincides with the loss of facultative particle attachment. Collectively, these observations support a recently developed macroevolutionary model, in which niche-constructing radiations allowed ancestral lineages of picocyanobacteria to transition from a particle-attached to planktonic lifestyle and broadly colonize the euphotic zone.<b>IMPORTANCE</b>The marine cyanobacterium, <i>Prochlorococcus</i>, is among the Earth's most abundant organisms, and much of its genetic and physiological diversity remains uncharacterized. Although field studies help reveal the scope of diversity, cultured isolates allow us to link genomic potential to physiological processes, illuminate eco-evolutionary feedbacks, and test theories arising from comparative genomics of wild cells. Here, we report the isolation and characterization of novel low-light (LL)-adapted <i>Prochlorococcus</i> strains that fill in multiple evolutionary gaps. These new strains are the first cultivated representatives of the LLVII and LLVIII paraphyletic grades of <i>Prochlorococcus</i>, which are broadly distributed in the lower regions of the ocean euphotic zone. Each of these grades is a unique, highly diverse section of the <i>Prochlorococcus</i> tree that separates distinct ecological groups: the LLVII grade branches between monophyletic clades that have facultatively particle-associated and constitutively planktonic lifestyles, whereas the LLVIII grade lies along the branch that leads to all high-light (HL)-adapted clades. Characterizing strains and genomes from these grades yields insights into the large-scale evolution of <i>Prochlorococcus</i>. Th
原绿球藻是一种多样化的微囊藻属,也是地球上最丰富的光营养体。其光合作用的多样性将其划分为适应高光(HL)或低光(LL)的群体,代表了广泛的系统发育等级--每个群体都由多个单系支系组成。在此,我们对从北太平洋深层叶绿素最高点以下分离出来的四株新的原绿球藻进行了生理特征描述。我们将这些生理特性与基因组分析相结合,探索光合触角的进化过程,并讨论其潜在的宏观进化意义。这些分离物属于低光适应性深分支支系,没有其他栽培代表,并显示出一些不寻常的特征。例如,尽管菌株 MIT1223 具有适应弱光的生理特征,但其 chl b2 含量较低,与适应强光的菌株相似。分离基因组显示,每个菌株都含有独特的色素生物合成和结合等位基因,这些等位基因是横向获得的,导致了观察到的生理多样性。对所有微囊藻进行的基因组比较分析表明,Pcb 是原绿球藻中主要的色素携带蛋白,其每个基因组的拷贝数和多样性都大大增加,而这一分支恰好与丧失面性颗粒附着相吻合。总体而言,这些观察结果支持了最近提出的宏观进化模型,即生态位构建辐射使微囊藻的祖先品系从颗粒附着型生活方式过渡到浮游型生活方式,并在极光带广泛定殖。尽管野外研究有助于揭示其多样性的范围,但培养分离物使我们能够将基因组潜力与生理过程联系起来,阐明生态进化反馈,并检验野生细胞比较基因组学所产生的理论。在这里,我们报告了新的适应低光照(LL)的原氯球藻菌株的分离和特征描述,这些菌株填补了多个进化空白。这些新菌株是 LLVII 和 LLVIII 副系原绿球藻的首批栽培代表,它们广泛分布于海洋极光带的较低区域。这些等级是原绿球藻树中独特的、高度多样化的部分,将不同的生态群组分开:LLVII 等级在单系支系之间分支,这些单系支系具有与颗粒相关的面生生活方式和浮游生活方式,而 LLVIII 等级则位于通向所有高光(HL)适应支系的分支上。对这些等级的菌株和基因组进行鉴定,可以深入了解原绿球藻的大规模进化过程。新的 LLVII 和 LLVIII 菌株适应在极低的辐照度水平下生长,具有独特的采光基因特征和色素沉着。LLVII 菌株代表了最基本的原绿球菌类群,其光合触角基因有重大扩展。此外,来自 LLVIII 级的一株菌株挑战了所有适应 LL 的原绿球藻都表现出高 chl b:a2 比率的模式。这些发现有助于深入了解原绿球藻的光生理学进化,并重新定义了低光适应与高光适应原绿球藻细胞的含义。
{"title":"Novel isolates expand the physiological diversity of <i>Prochlorococcus</i> and illuminate its macroevolution.","authors":"Jamie W Becker, Shaul Pollak, Jessie W Berta-Thompson, Kevin W Becker, Rogier Braakman, Keven D Dooley, Thomas Hackl, Allison Coe, Aldo Arellano, Kristen N LeGault, Paul M Berube, Steven J Biller, Andrés Cubillos-Ruiz, Benjamin A S Van Mooy, Sallie W Chisholm","doi":"10.1128/mbio.03497-23","DOIUrl":"10.1128/mbio.03497-23","url":null,"abstract":"&lt;p&gt;&lt;p&gt;&lt;i&gt;Prochlorococcus&lt;/i&gt; is a diverse picocyanobacterial genus and the most abundant phototroph on Earth. Its photosynthetic diversity divides it into high-light (HL)- or low-light (LL)-adapted groups representing broad phylogenetic grades-each composed of several monophyletic clades. Here, we physiologically characterize four new &lt;i&gt;Prochlorococcus&lt;/i&gt; strains isolated from below the deep chlorophyll maximum in the North Pacific Ocean. We combine these physiological properties with genomic analyses to explore the evolution of photosynthetic antennae and discuss potential macroevolutionary implications. The isolates belong to deeply branching low-light-adapted clades that have no other cultivated representatives and display some unusual characteristics. For example, despite its otherwise low-light-adapted physiological characteristics, strain MIT1223 has low chl &lt;i&gt;b&lt;sub&gt;2&lt;/sub&gt;&lt;/i&gt; content similar to high-light-adapted strains. Isolate genomes revealed that each strain contains a unique arsenal of pigment biosynthesis and binding alleles that have been horizontally acquired, contributing to the observed physiological diversity. Comparative genomic analysis of all picocyanobacteria reveals that Pcb, the major pigment carrying protein in &lt;i&gt;Prochlorococcus&lt;/i&gt;, greatly increased in copy number and diversity per genome along a branch that coincides with the loss of facultative particle attachment. Collectively, these observations support a recently developed macroevolutionary model, in which niche-constructing radiations allowed ancestral lineages of picocyanobacteria to transition from a particle-attached to planktonic lifestyle and broadly colonize the euphotic zone.&lt;b&gt;IMPORTANCE&lt;/b&gt;The marine cyanobacterium, &lt;i&gt;Prochlorococcus&lt;/i&gt;, is among the Earth's most abundant organisms, and much of its genetic and physiological diversity remains uncharacterized. Although field studies help reveal the scope of diversity, cultured isolates allow us to link genomic potential to physiological processes, illuminate eco-evolutionary feedbacks, and test theories arising from comparative genomics of wild cells. Here, we report the isolation and characterization of novel low-light (LL)-adapted &lt;i&gt;Prochlorococcus&lt;/i&gt; strains that fill in multiple evolutionary gaps. These new strains are the first cultivated representatives of the LLVII and LLVIII paraphyletic grades of &lt;i&gt;Prochlorococcus&lt;/i&gt;, which are broadly distributed in the lower regions of the ocean euphotic zone. Each of these grades is a unique, highly diverse section of the &lt;i&gt;Prochlorococcus&lt;/i&gt; tree that separates distinct ecological groups: the LLVII grade branches between monophyletic clades that have facultatively particle-associated and constitutively planktonic lifestyles, whereas the LLVIII grade lies along the branch that leads to all high-light (HL)-adapted clades. Characterizing strains and genomes from these grades yields insights into the large-scale evolution of &lt;i&gt;Prochlorococcus&lt;/i&gt;. Th","PeriodicalId":18315,"journal":{"name":"mBio","volume":" ","pages":"e0349723"},"PeriodicalIF":5.1,"publicationDate":"2024-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11559063/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142469442","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
The Candida auris Hog1 MAP kinase is essential for the colonization of murine skin and intradermal persistence. 白色念珠菌 Hog1 MAP 激酶对小鼠皮肤的定殖和皮内持久性至关重要。
IF 5.1 1区 生物学 Q1 MICROBIOLOGY Pub Date : 2024-11-13 Epub Date: 2024-10-18 DOI: 10.1128/mbio.02748-24
Raju Shivarathri, Manju Chauhan, Abhishek Datta, Diprasom Das, Adela Karuli, Ariel Aptekmann, Sabrina Jenull, Karl Kuchler, Shankar Thangamani, Anuradha Chowdhary, Jigar V Desai, Neeraj Chauhan

Candida auris, a multidrug-resistant human fungal pathogen, was first identified in 2009 in Japan. Since then, systemic C. auris infections have now been reported in more than 50 countries, with mortality rates of 30%-60%. A major contributing factor to its high inter- and intrahospital clonal transmission is that C. auris, unlike most Candida species, displays unique skin tropism and can stay on human skin for a prolonged period. However, the molecular mechanisms responsible for C. auris skin colonization, intradermal persistence, and systemic virulence are poorly understood. Here, we report that C. auris Hog1 mitogen-activated protein kinase is essential for efficient skin colonization, intradermal persistence as well as systemic virulence. RNA-seq analysis of wild-type parental and hog1Δ mutant strains revealed marked downregulation of genes involved in processes such as cell adhesion, cell wall rearrangement, and pathogenesis in hog1Δ mutant compared to the wild-type parent. Consistent with these data, we found a prominent role for Hog1 in maintaining cell wall architecture, as the hog1Δ mutant demonstrated a significant increase in cell-surface β-glucan exposure and a concomitant reduction in chitin content. Additionally, we observed that Hog1 was required for biofilm formation in vitro and fungal survival when challenged with primary murine macrophages and neutrophils ex vivo. Collectively, these findings have important implications for understanding the C. auris skin adherence mechanisms and penetration of skin epithelial layers preceding bloodstream infections.

Importance: Candida auris is a World Health Organization fungal priority pathogen and an urgent public health threat recognized by the Centers for Disease Control and Prevention. C. auris has a unique ability to colonize human skin. It also persists on abiotic surfaces in healthcare environments for an extended period of time. These attributes facilitate the inter- and intrahospital clonal transmission of C. auris. Therefore, understanding C. auris skin colonization mechanisms is critical for infection control, especially in hospitals and nursing homes. However, despite its profound clinical relevance, the molecular and genetic basis of C. auris skin colonization mechanisms are poorly understood. Herein, we present data on the identification of the Hog1 MAP kinase as a key regulator of C. auris skin colonization. These findings lay the foundation for further characterization of unique mechanisms that promote fungal persistence on human skin.

念珠菌是一种具有多重耐药性的人类真菌病原体,2009 年首次在日本被发现。从那时起,50 多个国家报告了系统性念珠菌感染,死亡率高达 30%-60%。造成其在医院间和医院内高度克隆传播的一个主要因素是,与大多数念珠菌不同,阿脲酵母菌具有独特的皮肤滋养性,可在人体皮肤上长期存在。然而,人们对 C. auris 皮肤定殖、皮内持久性和全身毒性的分子机制知之甚少。在此,我们报告了 C. auris Hog1 丝裂原活化蛋白激酶对皮肤的高效定殖、皮内持久性和全身毒力至关重要。对野生型亲本和 hog1Δ 突变株的 RNA-seq 分析显示,与野生型亲本相比,hog1Δ 突变株中参与细胞粘附、细胞壁重排和致病过程的基因明显下调。与这些数据一致的是,我们发现 Hog1 在维持细胞壁结构方面起着重要作用,因为 hog1Δ 突变体的细胞表面 β-葡聚糖暴露显著增加,同时几丁质含量减少。此外,我们还观察到,Hog1 是体外生物膜形成和真菌在小鼠原代巨噬细胞和中性粒细胞体内存活的必要条件。总之,这些发现对了解阿氏念珠菌的皮肤粘附机制和血液感染前皮肤上皮细胞层的渗透具有重要意义:重要意义:白色念珠菌是世界卫生组织重点关注的真菌病原体,也是美国疾病控制和预防中心认定的一种紧迫的公共卫生威胁。念珠菌具有在人体皮肤上定植的独特能力。它还能在医疗环境的非生物表面长期存在。这些特性促进了 C. auris 在医院间和医院内的克隆传播。因此,了解 C. auris 的皮肤定植机制对于感染控制至关重要,尤其是在医院和疗养院。然而,尽管它与临床密切相关,但人们对 C. auris 皮肤定植机制的分子和遗传基础却知之甚少。在本文中,我们展示了关于 Hog1 MAP 激酶作为 C. auris 皮肤定植关键调控因子的鉴定数据。这些发现为进一步确定促进真菌在人体皮肤上持续存在的独特机制奠定了基础。
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引用次数: 0
The ribosome-associated quality control pathway supports survival in the absence of non-stop ribosome rescue factors. 核糖体相关质量控制途径可在缺乏不间断核糖体拯救因子的情况下支持存活。
IF 5.1 1区 生物学 Q1 MICROBIOLOGY Pub Date : 2024-11-13 DOI: 10.1128/mbio.02322-24
Katrina Callan, Cassidy R Prince, Heather A Feaga

In bacteria, if a ribosome translates an mRNA lacking a stop codon it becomes stalled at the 3' end of the message. These ribosomes must be rescued by trans-translation or the alternative rescue factors (ArfA or ArfB). However, mounting evidence suggests that the ribosome quality control (RQC) pathway may also rescue non-stop ribosomes. Here, we surveyed the conservation of ribosome rescue pathways in >15,000 bacterial genomes. We found that trans-translation is conserved in >97% of bacterial genomes, while the other rescue pathways are restricted to particular phyla. We did not detect the gene encoding RqcH, the major mediator of RQC, in Proteobacteria (Pseudomonadota). In all Proteobacteria investigated to date, trans-translation is essential in the absence of the Arf proteins. Therefore, we tested whether expression of RQC components from Bacillus subtilis could rescue viability in the absence of trans-translation and ArfA in Escherichia coli. We found that the RQC pathway indeed functions in E. coli and rescues the well-documented synthetic lethal phenotype of ∆ssrAarfA. Moreover, we show that the RQC pathway in B. subtilis is essential in the absence of trans-translation and ArfA, further supporting a role for the RQC pathway in the rescue of non-stop ribosomes. Finally, we report a strong co-occurrence between RqcH and the ribosome splitting factor MutS2, but present experimental evidence that there are likely additional ribosome splitting factors beyond MutS2 in B. subtilis. Altogether, our work supports a role for RQC in non-stop ribosome rescue and provides a broad survey of ribosome rescue pathways in diverse bacteria.

Importance: In bacteria, it is estimated that 2%-4% of all translation reactions terminate with the ribosome stalled on a damaged mRNA lacking a stop codon. Mechanisms that rescue these ribosomes are essential for viability. We determined the functional overlap between the ribosome quality control pathway and the classical non-stop rescue systems [alternative rescue factor (ArfA) and trans-translation] in a representative Firmicute and Proteobacterium, phyla that are evolutionarily distinct. Furthermore, we used a bioinformatics approach to examine the conservation and overlap of various ribosome rescue systems in >15,000 species throughout the bacterial domain. These results provide key insights into ribosome rescue in diverse phyla.

在细菌中,如果核糖体翻译缺少终止密码子的 mRNA,就会停滞在信息的 3' 端。这些核糖体必须通过转译或替代拯救因子(ArfA 或 ArfB)来拯救。然而,越来越多的证据表明,核糖体质量控制(RQC)途径也可能挽救不停止的核糖体。在这里,我们调查了超过 15,000 个细菌基因组中核糖体拯救途径的保存情况。我们发现,转译在超过 97% 的细菌基因组中是保守的,而其他拯救途径则仅限于特定的门类。我们在变形菌(假单胞菌)中没有检测到编码 RQC 主要介质 RqcH 的基因。在迄今为止调查过的所有变形菌中,在没有 Arf 蛋白的情况下,转译是必不可少的。因此,我们测试了枯草芽孢杆菌 RQC 成分的表达能否在大肠杆菌缺乏转译和 ArfA 的情况下挽救其生命力。我们发现,RQC 通路在大肠杆菌中确实起作用,并能挽救已被充分证明的 ∆ssrA∆arfA 合成致死表型。此外,我们还发现在缺乏转译和 ArfA 的情况下,枯草芽孢杆菌中的 RQC 通路也是必不可少的,这进一步支持了 RQC 通路在挽救非停止核糖体中的作用。最后,我们报告了 RqcH 与核糖体分裂因子 MutS2 之间的密切共存关系,但实验证据表明,除了 MutS2 之外,枯草杆菌中可能还有其他核糖体分裂因子。总之,我们的工作支持了 RQC 在不停顿核糖体拯救中的作用,并提供了对不同细菌中核糖体拯救途径的广泛调查:在细菌中,据估计有 2%-4% 的翻译反应因核糖体停滞在缺乏终止密码子的受损 mRNA 上而终止。挽救这些核糖体的机制对于生存至关重要。我们确定了核糖体质量控制途径与经典不停顿拯救系统 [替代拯救因子(ArfA)和转译] 在具有代表性的固氮菌和变形菌(进化过程中截然不同的门类)中的功能重叠。此外,我们还利用生物信息学方法,研究了整个细菌领域超过 15,000 个物种中各种核糖体救援系统的保护和重叠情况。这些结果为我们深入了解不同门类的核糖体拯救系统提供了重要依据。
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引用次数: 0
The changing roles of scientific journals. 科学期刊不断变化的作用。
IF 5.1 1区 生物学 Q1 MICROBIOLOGY Pub Date : 2024-11-13 Epub Date: 2024-10-04 DOI: 10.1128/mbio.02515-24
Arturo Casadevall, Lorraine F Clark, Ferric C Fang

After centuries of relative stability, the scientific publishing world has undergone tremendous disruption and change during the first decades of the 21st century. The causes for disruption can be traced to the information revolution, which brought such benefits as rapid publication, greater connectivity, and ready access to large databases, along with less desirable practices including image manipulation, plagiarism, and other ethical transgressions. The information revolution has driven the proliferation of journals, expansion of for-profit academic publishing, and empowerment of the open-access movement, each of which has exerted new financial pressures on traditional publishing models. As journals became the focal point for ethical concerns in science, they have adapted by increasing the scope of their duties, which now include archiving of data, enforcement of good practices, establishment of standards for rigor, and training the next generation of reviewers and editors. Here, we consider the seismic changes occurring in scientific publishing and place them into the context of a rapidly changing landscape of scientific and publishing norms.

在经历了几个世纪的相对稳定之后,科学出版界在 21 世纪的头几十年经历了巨大的混乱和变化。造成混乱的原因可以追溯到信息革命,它带来了快速出版、更大的连通性和随时访问大型数据库等好处,同时也带来了一些不可取的做法,包括图片篡改、剽窃和其他违反道德的行为。信息革命推动了期刊的激增、营利性学术出版业的扩张以及开放获取运动的发展,而这一切都对传统出版模式造成了新的经济压力。随着期刊成为科学伦理问题的焦点,它们也做出了调整,扩大了自己的职责范围,现在包括数据归档、良好实践的实施、严谨性标准的建立以及下一代审稿人和编辑的培训。在此,我们将探讨科学出版领域正在发生的巨大变化,并将这些变化置于快速变化的科学和出版规范的背景之下。
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引用次数: 0
Plasmodium falciparum protein phosphatase PP7 is required for early ring-stage development. 恶性疟原虫蛋白磷酸酶 PP7 是早期环状发育所必需的。
IF 5.1 1区 生物学 Q1 MICROBIOLOGY Pub Date : 2024-11-13 Epub Date: 2024-10-10 DOI: 10.1128/mbio.02539-24
Avnish Patel, Aline Fréville, Joshua A Rey, Helen R Flynn, Konstantinos Koussis, Mark J Skehel, Michael J Blackman, David A Baker

We previously reported that the Plasmodium falciparum putative serine/threonine protein phosphatase 7 (PP7) is a high-confidence substrate of the cAMP-dependent protein kinase (PKA). Here we explore the function of PP7 in asexual P. falciparum blood stage parasites. We show that conditional disruption of PP7 leads to a severe growth arrest. We show that PP7 is a calcium-dependent phosphatase that interacts with calmodulin and calcium-dependent protein kinase 1 (CDPK1), consistent with a role in calcium signaling. Notably, PP7 was found to be dispensable for erythrocyte invasion, but was crucial for ring-stage development, with PP7-null parasites arresting shortly following invasion and showing no transition to ameboid forms. Phosphoproteomic analysis revealed that PP7 may regulate certain PKAc substrates. Its interaction with calmodulin and CDPK1 further emphasizes a role in calcium signaling, while its impact on early ring development and PKAc substrate phosphorylation underscores its importance in parasite development.

Importance: Plasmodium falciparum causes malaria and is responsible for more than 600,000 deaths each year. Although effective drugs are available to treat disease, the spread of drug-resistant parasites endangers their future efficacy. It is hoped that a better understanding of the biology of malaria parasites will help us to discover new drugs to tackle the resistance problem. Our work is focused on the cell signaling mechanisms that control the development of the parasite throughout its complex life cycle. All signal transduction pathways are ultimately regulated by reversible protein phosphorylation by protein kinase and protein phosphatase enzymes. In this study, we investigate the function of calcium-dependent protein phosphatase PP7 and show that it is essential for the development of ring-stage parasites following the invasion of human erythrocytes. Our results contribute to the understanding of the erythrocytic stages of the parasite life cycle that cause malaria pathology.

我们以前曾报道过恶性疟原虫假定丝氨酸/苏氨酸蛋白磷酸酶 7(PP7)是 cAMP 依赖性蛋白激酶(PKA)的高置信度底物。在这里,我们探讨了 PP7 在无性恶性疟原虫血期寄生虫中的功能。我们发现,条件性破坏 PP7 会导致严重的生长停滞。我们发现 PP7 是一种钙依赖性磷酸酶,能与钙调素和钙依赖性蛋白激酶 1(CDPK1)相互作用,这与 PP7 在钙信号转导中的作用一致。值得注意的是,研究发现PP7对红细胞侵袭是不可或缺的,但对环状阶段的发育却至关重要,PP7缺失的寄生虫在侵袭后不久就会停止发育,并且不会过渡到小型寄生虫形态。磷酸蛋白组分析表明,PP7 可调节某些 PKAc 底物。它与钙调蛋白和CDPK1的相互作用进一步强调了它在钙信号转导中的作用,而它对早期环发育和PKAc底物磷酸化的影响则强调了它在寄生虫发育中的重要性:恶性疟原虫会导致疟疾,每年造成 60 多万人死亡。虽然目前已有治疗疟疾的有效药物,但抗药性寄生虫的传播危及这些药物的未来疗效。我们希望,更好地了解疟原虫的生物学特性将有助于我们发现新的药物来解决抗药性问题。我们的工作重点是研究控制寄生虫整个复杂生命周期发展的细胞信号机制。所有信号转导途径最终都受到蛋白激酶和蛋白磷酸酶可逆蛋白磷酸化的调控。在这项研究中,我们研究了钙依赖性蛋白磷酸酶 PP7 的功能,结果表明它对入侵人体红细胞后的环期寄生虫的发育至关重要。我们的研究结果有助于人们了解导致疟疾病理的寄生虫生命周期的红细胞阶段。
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引用次数: 0
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