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Neutrophil prime unique transcriptional responses in intestinal organoids during infection with nontyphoidal Salmonella enterica serovars. 非伤寒沙门氏菌肠道血清型感染期间,中性粒细胞在肠道器官组织中的独特转录反应。
IF 3.7 2区 生物学 Q2 MICROBIOLOGY Pub Date : 2024-11-20 DOI: 10.1128/msphere.00693-24
Anna-Lisa E Lawrence, Ryan P Berger, David R Hill, Sha Huang, Veda K Yadagiri, Brooke Bons, Courtney Fields, Jason S Knight, Christiane E Wobus, Jason R Spence, Vincent B Young, Basel H Abuaita, Mary X O'Riordan

Nontyphoidal strains of Salmonella enterica are a major cause of foodborne illnesses, and infection with these bacteria results in inflammatory gastroenteritis. Polymorphonuclear leukocytes (PMNs), also known as neutrophils, are a dominant immune cell type found at the site of infection in Salmonella-infected individuals, but how they regulate infection outcome is not well understood. Here, we used a co-culture model of primary human PMNs and human intestinal organoids to probe the role of PMNs during infection with two of the most prevalent Salmonella serovars: Salmonella enterica serovar Enteritidis and Typhimurium. Using a transcriptomics approach, we identified a dominant role for PMNs in mounting differential immune responses including production of pro-inflammatory cytokines, chemokines, and antimicrobial peptides. We also identified specific gene sets that were induced by PMNs in response to Enteritidis or Typhimurium infection. By comparing host responses to these serovars, we uncovered differential regulation of host metabolic pathways particularly induction of cholesterol biosynthetic pathways during Typhimurium infection and suppression of RNA metabolism during Enteritidis infection. Together, these findings provide insight into the role of human PMNs in modulating different host responses to pathogens that cause similar disease in humans.IMPORTANCENontyphoidal serovars of Salmonella enterica are known to induce robust recruitment of polymorphonuclear leukocytes (PMNs) in the gut during early stages of infection, but the specific role of PMNs in regulating infection outcome of different serovars is poorly understood. Due to differences in human infection progression compared to small animal models, characterizing the role of PMNs during infection has been challenging. Here, we used a co-culture model of human intestinal organoids with human primary PMNs to study the role of PMNs during infection of human intestinal epithelium. Using a transcriptomics approach, we define PMN-dependent reprogramming of the host response to Salmonella, establishing a clear role in amplifying pro-inflammatory gene expression. Additionally, the host response driven by PMNs differed between two similar nontyphoidal Salmonella serovars. These findings highlight the importance of building more physiological infection models to replicate human infection conditions to study host responses specific to individual pathogens.

肠道沙门氏菌的非伤寒菌株是食源性疾病的主要病因,感染这些细菌会导致炎症性肠胃炎。多形核白细胞(PMNs)又称中性粒细胞,是沙门氏菌感染者感染部位的主要免疫细胞类型,但它们如何调节感染结果尚不十分清楚。在这里,我们使用原代人类 PMNs 和人类肠道器官组织的共培养模型来探究 PMNs 在感染两种最流行的沙门氏菌血清型时的作用:肠炎沙门氏菌和鼠伤寒沙门氏菌。利用转录组学方法,我们确定了 PMN 在启动不同免疫反应中的主导作用,包括产生促炎细胞因子、趋化因子和抗菌肽。我们还确定了 PMN 诱导肠炎嗜血杆菌或秋伤寒杆菌感染的特定基因集。通过比较宿主对这些血清的反应,我们发现了宿主代谢途径的不同调控,尤其是在感染 Typhimurium 时诱导胆固醇生物合成途径,而在感染 Enteritidis 时抑制 RNA 代谢。重要提示:众所周知,肠道沙门氏菌的非类风性血清型在感染早期会诱导肠道内多形核白细胞(PMN)的大量招募,但人们对 PMN 在调节不同血清型感染结果中的具体作用却知之甚少。由于人类感染过程与小动物模型不同,确定 PMNs 在感染过程中的作用具有挑战性。在这里,我们利用人体肠道器官组织与人类原发性 PMNs 的共培养模型来研究 PMNs 在人类肠道上皮细胞感染过程中的作用。通过转录组学方法,我们确定了沙门氏菌对宿主反应的重编程依赖于 PMN,从而明确了 PMN 在放大促炎基因表达中的作用。此外,由 PMN 驱动的宿主反应在两种类似的非伤寒沙门氏菌血清之间存在差异。这些发现强调了建立更多生理感染模型的重要性,以复制人类感染条件,研究宿主对个别病原体的特异性反应。
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引用次数: 0
Antibiotic tolerance due to restriction of cAMP-Crp regulation by mannitol, a non-glucose-family PTS carbon source. 抗生素耐受性源于甘露醇(一种非葡萄糖族 PTS 碳源)对 cAMP-Crp 调节的限制。
IF 3.7 2区 生物学 Q2 MICROBIOLOGY Pub Date : 2024-11-20 DOI: 10.1128/msphere.00772-24
Weiwei Zhu, Miaomiao Chen, Xue Zhang, Jie Su, Xinyang Zhang, Yuejuan Nong, Bowen Wang, Weihong Guo, Yunxin Xue, Dai Wang, Yiqun Liao, Jianjun Niu, Yuzhi Hong, Karl Drlica, Xilin Zhao
<p><p>Enzyme-IIA (EIIA<sup>Glc</sup>, Crr) of the phosphotransferase system (PTS) connects the uptake of glucose-family sugars to the cAMP-Crp regulatory cascade; phosphorylated EIIA<sup>Glc</sup> enhances cAMP-Crp activity, which then contributes to the antibiotic-mediated accumulation of reactive oxygen species (ROS) and cell death. Defects in PTS cause antibiotic and disinfectant tolerance. We report that mannitol, a carbon source whose uptake does not use EIIA<sup>Glc</sup>, reduces antibiotic-mediated killing of <i>Escherichia coli</i> without affecting antibiotic minimal inhibitory concentration. Thus, mannitol promotes antibiotic tolerance. The tolerance pathway was defined by the loss of ciprofloxacin lethality from the deletion of <i>ptsI</i> (first gene in PTS), <i>mtlA</i> (mannitol-specific Enzyme-II), <i>cyaA</i> (cAMP synthase), and <i>crp</i> (cAMP receptor protein) but not <i>crr</i> (EIIA<sup>Glc</sup>). A <i>crp*</i> mutant, which encodes a constitutively active Crp that bypasses the need for cAMP activation, also decreased mannitol-mediated antibiotic tolerance, as did exogenous cAMP. Thus, inhibition of antibiotic lethality by mannitol involves both PTS-mediated mannitol uptake and suppression of cAMP-Crp action, independent of EIIA<sup>Glc</sup>. Mannitol suppressed the downstream antibiotic-mediated transcription of genes involved in NADH production and cellular respiration, expression of a superoxide reporter gene (<i>soxS</i>), and accumulation of antibiotic-mediated ROS. Similar phenomena were observed with mannose and sorbitol, demonstrating that non-glucose PTS carbon sources can cause antibiotic tolerance by a novel path that reduces the ROS-promoting activity of cAMP-Crp. The work emphasizes that antibiotic tolerance, which contributes to disease relapse and the need for prolonged antibiotic treatment, can result from commonly consumed carbohydrates. This finding, plus mutations that interfere specifically with antibiotic lethality, makes tolerance a high probability event.IMPORTANCEBacterial tolerance constitutes a significant threat to anti-infective therapy and potentially to the use of disinfectants. Deficiency mutations that reduce glucose uptake, central carbon metabolism, and cellular respiration confer antibiotic/disinfectant tolerance by reducing the accumulation of reactive metabolites, such as reactive oxygen species. We identified novel environmental generators of tolerance by showing that non-glucose carbohydrates, such as mannitol, mannose, and sorbitol, generate tolerance to multiple antibiotic classes. Finding that these sugars inhibit a universal, stress-mediated death pathway emphasizes the potential danger of compounds that block the lethal response to severe stress. Immediate practical importance derives from mannitol being a popular food sweetener, a treatment for glaucoma, and a dehydrating agent for treating cerebral edema, including cases caused by bacterial infection: antibiotic tolerance coul
磷酸转移酶系统(PTS)的酶 IIA(EIIAGlc,Crrr)将葡萄糖族糖类的吸收与 cAMP-Crp 调控级联连接起来;磷酸化的 EIIAGlc 可增强 cAMP-Crp 活性,进而促进抗生素介导的活性氧(ROS)积累和细胞死亡。PTS 缺陷会导致抗生素和消毒剂耐受性。我们报告说,甘露醇是一种不使用 EIIAGlc 的碳源,它能减少抗生素介导的对大肠杆菌的杀灭,而不影响抗生素的最小抑菌浓度。因此,甘露醇能促进抗生素耐受性。耐受途径是通过缺失 ptsI(PTS 的第一个基因)、mtlA(甘露醇特异性酶-II)、cyaA(cAMP 合成酶)和 crp(cAMP 受体蛋白)而非 crr(EIIAGlc)导致环丙沙星致死率的丧失来确定的。crp*突变体(编码一种绕过 cAMP 激活需要的组成型活性 Crp)也会降低甘露醇介导的抗生素耐受性,外源 cAMP 也是如此。因此,甘露醇对抗生素致死性的抑制涉及 PTS 介导的甘露醇吸收和 cAMP-Crp 作用的抑制,与 EIIAGlc 无关。甘露醇抑制了下游抗生素介导的参与 NADH 生成和细胞呼吸的基因转录、超氧化物报告基因(soxS)的表达以及抗生素介导的 ROS 的积累。在甘露糖和山梨醇中也观察到了类似的现象,这表明非葡萄糖 PTS 碳源可以通过一种新的途径降低 cAMP-Crp 的 ROS 促进活性,从而导致抗生素耐受性。这项研究强调,抗生素耐受性可由常见的碳水化合物引起,而抗生素耐受性会导致疾病复发并需要长期的抗生素治疗。重要意义细菌耐受性对抗感染治疗构成了重大威胁,并有可能影响消毒剂的使用。通过减少活性代谢产物(如活性氧)的积累,减少葡萄糖摄取、中心碳代谢和细胞呼吸的缺陷突变可产生抗生素/消毒剂耐受性。通过证明甘露醇、甘露糖和山梨醇等非葡萄糖碳水化合物能产生对多种抗生素的耐受性,我们发现了耐受性的新型环境生成物。发现这些糖能抑制一种普遍的、应激介导的死亡途径,强调了阻断严重应激致死反应的化合物的潜在危险。甘露醇是一种常用的食品甜味剂,也是一种治疗青光眼的药物,还是一种治疗脑水肿(包括细菌感染引起的脑水肿)的脱水剂:抗生素耐受性可能会使抗生素治疗期间禁用甘露醇和相关碳水化合物。总之,这项研究表明,在使用抗菌剂或消毒剂时必须考虑糖类的存在。
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引用次数: 0
Whole genome sequencing revealed high proportions of ST152 MRSA among clinical Staphylococcus aureus isolates from ten hospitals in Ghana. 全基因组测序显示,在加纳 10 家医院的临床金黄色葡萄球菌分离物中,ST152 MRSA 的比例很高。
IF 3.7 2区 生物学 Q2 MICROBIOLOGY Pub Date : 2024-11-20 DOI: 10.1128/msphere.00446-24
Beverly Egyir, Christian Owusu-Nyantakyi, Alfred Bortey, Grebstad Rabbi Amuasi, Felicia Amoa Owusu, William Boateng, Hawawu Ahmed, Justice Kwesi Danso, Agnes Akosua Gyamaah Oclu, Quaneeta Mohktar, Georgina Tetteh-Ocloo, Harold Amegbletor, Kwabena Fosu, Francis Kwame Morgan Tetteh, Solomon Asante-Sefa, Oliver Nangkuu Deberu, Kennedy Mensah Osei, Joana Twasam, Sarkodie Kodom, Esther Gyinae, James Sampah, Nicholas Dzifa Dayie, Noah Obeng-Nkrumah, William Addo Mills-Pappoe, Gifty Boateng, Pernille Nilsson, Harriet Affran Bonful, Bright Adu, Rene S Hendriksen

Previous studies in Ghana indicated low prevalence of methicillin-resistant Staphylococcus aureus (MRSA) and predominance of ST152 methicillin-susceptible S. aureus (MSSA) among clinical isolates. ST152 MRSA clones are associated with severe infections and epidemics. Using whole genome sequencing (WGS), 159 S. aureus isolated from clinical sources (wound, blood, urine, ear, abscess, umbilical cord, eye, vaginal samples, and others) from 10 hospitals across Ghana were investigated. mecA (gene for methicillin resistance) was detected in 38% of the isolates. Panton-Valentine leucocidin toxin (PVL) gene occurred in 65% isolates, with 84% of the MRSA's harboring the PVL gene. ST152 was the major clone, with 74% harboring the mecA gene. Other MRSA clones detected were ST5, ST5204, ST852, and ST1. MSSA clones included ST3249, ST152, ST5, ST1, and ST8. Twenty-three genes encoding resistance to 12 antimicrobial classes were observed with blaZ (97%) being the most prevalent. Other predominant resistance genes included tetK (46%), cat (42%), and dfrG (36%) encoding resistance for tetracyclines, phenicols, and diaminopyrimidine, respectively. Virulence genes for enterotoxins, biofilms, toxic-shock-syndrome toxins, hemolysins, and leukotoxins were also detected. Phylogenetic analysis revealed a shift in the dominant clone from MSSA ST152 to MRSA ST152 over the past decade. The study provides valuable insights into the genomic content of S. aureus from clinical sources in Ghana. The finding of ST152 MRSA in high numbers suggests a shifting epidemiological landscape of these pathogens and continuous surveillance using robust tools like WGS is needed to monitor the rise and spread of these epidemic clones in the country.IMPORTANCESince its emergence in 1959, MRSA has been a significant public health concern, causing infections in both clinical and community settings. Patients with MRSA-related infections experience higher mortality rates due to its ability to evade antimicrobials and immune defenses. In Ghana, understanding the molecular epidemiology of MRSA has been hindered by the lack of appropriate laboratory infrastructure and the limited capacity for molecular data analysis. This study, the largest genomic study of S. aureus in Ghana, addresses this gap by utilizing whole genome sequencing to examine the diversity of circulating S. aureus strains from 10 hospitals. Our findings highlight the predominance of pandemic clones, particularly ST152, and the notable transition of ST152 MSSA to ST152 MRSA over the past decade. The findings from this study supports AMR surveillance efforts in Ghana and emphasize the importance of implementing genomic surveillance using WGS to comprehensively monitor the rise and spread of multi-drug-resitant organisms such as MRSA in the country.

以前在加纳进行的研究表明,耐甲氧西林金黄色葡萄球菌(MRSA)的发病率较低,而在临床分离物中,ST152 甲氧西林易感金黄色葡萄球菌(MSSA)占主导地位。ST152 MRSA 克隆与严重感染和流行病有关。利用全基因组测序(WGS)技术,对从加纳 10 家医院的临床样本(伤口、血液、尿液、耳部、脓肿、脐带、眼部、阴道样本等)中分离出的 159 株金黄色葡萄球菌进行了调查,在 38% 的分离株中检测到了 mecA(耐甲氧西林基因)。65%的分离株含有潘顿-瓦伦丁白细胞毒素(PVL)基因,84%的 MRSA 含有 PVL 基因。ST152是主要的克隆,74%携带mecA基因。检测到的其他 MRSA 克隆有 ST5、ST5204、ST852 和 ST1。MSSA 克隆包括 ST3249、ST152、ST5、ST1 和 ST8。观察到的 23 个基因编码对 12 种抗菌药的耐药性,其中以 blaZ(97%)最为普遍。其他主要抗性基因包括 tetK(46%)、cat(42%)和 dfrG(36%),分别编码对四环素类、酚类和二氨基嘧啶的抗性。此外,还检测到了肠毒素、生物膜、毒性休克综合征毒素、溶血素和白细胞毒素的致病基因。系统发育分析表明,在过去十年中,优势克隆从 MSSA ST152 转变为 MRSA ST152。这项研究为了解加纳临床来源金黄色葡萄球菌的基因组含量提供了宝贵的信息。大量 ST152 MRSA 的发现表明,这些病原体的流行病学格局正在发生变化,因此需要使用 WGS 等强大的工具进行持续监测,以监控这些流行克隆在该国的增加和传播情况。重要意义自 1959 年出现以来,MRSA 一直是一个重大的公共卫生问题,在临床和社区环境中都会引起感染。由于 MRSA 能够逃避抗菌药物和免疫防御,因此与 MRSA 相关的感染患者死亡率较高。在加纳,由于缺乏适当的实验室基础设施和分子数据分析能力有限,对 MRSA 分子流行病学的了解一直受到阻碍。本研究是加纳规模最大的金黄色葡萄球菌基因组研究,它利用全基因组测序技术检测了来自 10 家医院的循环金黄色葡萄球菌菌株的多样性,从而弥补了这一不足。我们的研究结果突显了大流行克隆(尤其是 ST152)的优势,以及在过去十年中 ST152 MSSA 向 ST152 MRSA 的显著转变。这项研究的结果支持了加纳的 AMR 监控工作,并强调了利用 WGS 实施基因组监控以全面监控 MRSA 等多重耐药菌在该国的增加和传播的重要性。
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引用次数: 0
CRISPR-Cas9-based approaches for genetic analysis and epistatic interaction studies in Coxiella burnetii. 基于 CRISPR-Cas9 的烧伤柯西氏菌遗传分析和表观相互作用研究方法。
IF 3.7 2区 生物学 Q2 MICROBIOLOGY Pub Date : 2024-11-19 DOI: 10.1128/msphere.00523-24
Samuel Steiner, Craig R Roy

Coxiella burnetii is an obligate intracellular bacterial pathogen that replicates to high numbers in an acidified lysosome-derived vacuole. Intracellular replication requires the Dot/Icm type IVB secretion system, which translocates over 100 different effector proteins into the host cell. Screens employing random transposon mutagenesis have identified several C. burnetii effectors that play an important role in intracellular replication; however, the difficulty in conducting directed mutagenesis has been a barrier to the systematic analysis of effector mutants and to the construction of double mutants to assess epistatic interactions between effectors. Here, two CRISPR-Cas9 technology-based approaches were developed to study C. burnetii phenotypes resulting from targeted gene disruptions. CRISPRi was used to silence gene expression and demonstrated that silencing of effectors or Dot/Icm system components resulted in phenotypes similar to those of transposon insertion mutants. A CRISPR-Cas9-mediated cytosine base editing protocol was developed to generate targeted loss-of-function mutants through the introduction of premature stop codons into C. burnetii genes. Cytosine base editing successfully generated double mutants in a single step. A double mutant deficient in both cig57 and cig2 had a robust and additive intracellular replication defect when compared to either single mutant, which is consistent with Cig57 and Cig2 functioning in independent pathways that both contribute to a vacuole that supports C. burnetii replication. Thus, CRISPR-Cas9-based technologies expand the genetic toolbox for C. burnetii and will facilitate genetic studies aimed at investigating the mechanisms this pathogen uses to replicate inside host cells.

Importance: Understanding the genetic mechanisms that enable C. burnetii to replicate in mammalian host cells has been hampered by the difficulty in making directed mutations. Here, a reliable and efficient system for generating targeted loss-of-function mutations in C. burnetii using a CRISPR-Cas9-assisted base editing approach is described. This technology was applied to make double mutants in C. burnetii that enabled the genetic analysis of two genes that play independent roles in promoting the formation of vacuoles that support intracellular replication. This advance will accelerate the discovery of mechanisms important for C. burnetii host infection and disease.

烧伤柯西氏菌是一种强制性细胞内细菌病原体,可在酸化溶酶体衍生的空泡中大量复制。细胞内复制需要 Dot/Icm IVB 型分泌系统,它能将 100 多种不同的效应蛋白转运到宿主细胞中。采用随机转座子诱变的筛选方法发现了几种在细胞内复制中发挥重要作用的伯恩氏菌效应子;然而,定向诱变的困难阻碍了对效应子突变体的系统分析,也阻碍了构建双突变体以评估效应子之间的表观相互作用。在这里,我们开发了两种基于 CRISPR-Cas9 技术的方法来研究烧伤蜱因定向基因破坏而产生的表型。CRISPRi被用于沉默基因表达,结果表明,沉默效应子或Dot/Icm系统成分会导致与转座子插入突变体相似的表型。研究人员开发了一种 CRISPR-Cas9 介导的胞嘧啶碱基编辑方案,通过在 C. burnetii 基因中引入过早终止密码子来产生有针对性的功能缺失突变体。胞嘧啶碱基编辑只需一步就能成功生成双突变体。与任一单突变体相比,同时缺失 cig57 和 cig2 的双突变体具有强健的、可叠加的胞内复制缺陷,这与 Cig57 和 Cig2 在独立途径中发挥作用是一致的,它们都有助于形成支持烧伤蜱复制的空泡。因此,基于CRISPR-Cas9的技术扩大了烧伤桿菌的遗传工具箱,并将促进旨在研究这种病原体在宿主细胞内复制机制的遗传研究:由于难以进行定向突变,人们对烧伤蜱在哺乳动物宿主细胞内复制的遗传机制的了解一直受到阻碍。本文介绍了一种利用 CRISPR-Cas9 辅助碱基编辑方法在烧伤蜱中产生定向功能缺失突变的可靠而高效的系统。这项技术被用于制造烧伤蜱的双突变体,从而能够对两个基因进行遗传分析,这两个基因在促进形成支持细胞内复制的空泡方面发挥着独立的作用。这一进展将加速发现烧伤蜱宿主感染和疾病的重要机制。
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引用次数: 0
Erratum for Longley et al., "Signatures of Mollicutes-related endobacteria in publicly available Mucoromycota genomes". 对 Longley 等人 "在公开的粘菌基因组中发现与毛霉菌有关的内生细菌的特征 "的勘误。
IF 3.7 2区 生物学 Q2 MICROBIOLOGY Pub Date : 2024-11-18 DOI: 10.1128/msphere.00881-24
Reid Longley, Aaron J Robinson, Olivia A Asher, Earl Middlebrook, Gregory Bonito, Patrick S G Chain
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引用次数: 0
Similarities and distinctions in the activation of the Candida glabrata Pdr1 regulatory pathway by azole and non-azole drugs. 唑类药物和非唑类药物激活光滑念珠菌 Pdr1 调节途径的异同。
IF 3.7 2区 生物学 Q2 MICROBIOLOGY Pub Date : 2024-11-18 DOI: 10.1128/msphere.00792-24
Thomas P Conway, Bao Gia Vu, Sarah R Beattie, Damian J Krysan, W Scott Moye-Rowley

Incidences of fluconazole (FLC) resistance among Candida glabrata clinical isolates are a growing issue in clinics. The pleiotropic drug response network in C. glabrata confers azole resistance and is defined primarily by the Zn2Cys6 zinc cluster-containing transcription factor Pdr1 and target genes such as CDR1, which encodes an ATP-binding cassette transporter protein thought to act as an FLC efflux pump. Mutations in the PDR1 gene that render the transcription factor hyperactive are the most common cause of fluconazole resistance among clinical isolates. The phenothiazine class drug fluphenazine and a molecular derivative, CWHM-974, which both exhibit antifungal properties, have been shown to induce the expression of Cdr1 in Candida spp. We have used a firefly luciferase reporter gene driven by the CDR1 promoter to demonstrate two distinct patterns of CDR1 promoter activation kinetics: gradual promoter activation kinetics that occur in response to ergosterol limitations imposed by exposure to azole and polyene class antifungals and a robust and rapid CDR1 induction occurring in response to the stress imposed by fluphenazines. We can attribute these different patterns of CDR1 induction as proceeding through the promoter region of this gene since this is the only segment of the gene included in the luciferase reporter construct. Genetic analysis indicates that the signaling pathways responsible for phenothiazine and azole induction of CDR1 overlap but are not identical. The short time course of phenothiazine induction suggests that these compounds may act more directly on the Pdr1 protein to stimulate its activity.

Importance: Candida glabrata has emerged as the second-leading cause of candidiasis due, in part, to its ability to acquire high-level resistance to azole drugs, a major class of antifungal that acts to block the biosynthesis of the fungal sterol ergosterol. The presence of azole drugs causes the induction of a variety of genes involved in controlling susceptibility to this drug class, including drug transporters and ergosterol biosynthetic genes such as ERG11. We found that the presence of azole drugs leads to an induction of genes encoding drug transporters and ERG11, while exposure of C. glabrata cells to antifungals of the phenothiazine class of drugs caused a much faster and larger induction of drug transporters but not ERG11. Coupled with further genetic analyses of the effects of azole and phenothiazine drugs, our data indicate that these compounds are sensed and responded to differentially in the yeast cell.

光滑念珠菌(Candida glabrata)临床分离株对氟康唑(FLC)产生耐药性的问题在临床上日益严重。草绿色念珠菌的多效药物反应网络具有唑类耐药性,主要由 Zn2Cys6 含锌簇转录因子 Pdr1 和 CDR1 等靶基因定义,CDR1 编码一种 ATP 结合盒转运蛋白,被认为是一种 FLC 外排泵。PDR1 基因突变导致转录因子过度活跃,是临床分离株对氟康唑产生抗药性的最常见原因。吩噻嗪类药物氟奋乃静和一种分子衍生物 CWHM-974 都具有抗真菌特性,已被证明能诱导念珠菌属中 Cdr1 的表达。我们使用了由 CDR1 启动子驱动的萤火虫荧光素酶报告基因,证明了 CDR1 启动子激活动力学的两种不同模式:一种是在接触唑类和多烯类抗真菌药物后,因麦角固醇的限制而出现的渐进式启动子激活动力学;另一种是在氟吩嗪类抗真菌药物的压力下出现的强大而快速的 CDR1 诱导。我们可以将这些不同的 CDR1 诱导模式归结为通过该基因的启动子区域进行的,因为这是荧光素酶报告基因构建体中包含的唯一基因片段。遗传分析表明,吩噻嗪和唑类诱导 CDR1 的信号途径有重叠,但并不相同。吩噻嗪诱导的短时间过程表明,这些化合物可能更直接地作用于 Pdr1 蛋白,以刺激其活性:胶状念珠菌已成为念珠菌病的第二大致病菌,部分原因是它能够获得对唑类药物的高度耐药性,而唑类药物是一类主要的抗真菌药物,其作用是阻止真菌固醇麦角固醇的生物合成。唑类药物的存在会诱导多种参与控制对该类药物敏感性的基因,包括药物转运体和麦角甾醇生物合成基因(如 ERG11)。我们发现,唑类药物的存在会诱导编码药物转运体和ERG11的基因,而将草履虫细胞暴露于吩噻嗪类抗真菌药物会更快更大程度地诱导药物转运体,但不会诱导ERG11。结合对唑类和吩噻嗪类药物作用的进一步遗传分析,我们的数据表明,这些化合物在酵母细胞中的感应和反应是不同的。
{"title":"Similarities and distinctions in the activation of the <i>Candida glabrata</i> Pdr1 regulatory pathway by azole and non-azole drugs.","authors":"Thomas P Conway, Bao Gia Vu, Sarah R Beattie, Damian J Krysan, W Scott Moye-Rowley","doi":"10.1128/msphere.00792-24","DOIUrl":"https://doi.org/10.1128/msphere.00792-24","url":null,"abstract":"<p><p>Incidences of fluconazole (FLC) resistance among <i>Candida glabrata</i> clinical isolates are a growing issue in clinics. The pleiotropic drug response network in <i>C. glabrata</i> confers azole resistance and is defined primarily by the Zn<sub>2</sub>Cys<sub>6</sub> zinc cluster-containing transcription factor Pdr1 and target genes such as <i>CDR1</i>, which encodes an ATP-binding cassette transporter protein thought to act as an FLC efflux pump. Mutations in the <i>PDR1</i> gene that render the transcription factor hyperactive are the most common cause of fluconazole resistance among clinical isolates. The phenothiazine class drug fluphenazine and a molecular derivative, CWHM-974, which both exhibit antifungal properties, have been shown to induce the expression of Cdr1 in <i>Candida</i> spp. We have used a firefly luciferase reporter gene driven by the <i>CDR1</i> promoter to demonstrate two distinct patterns of <i>CDR1</i> promoter activation kinetics: gradual promoter activation kinetics that occur in response to ergosterol limitations imposed by exposure to azole and polyene class antifungals and a robust and rapid <i>CDR1</i> induction occurring in response to the stress imposed by fluphenazines. We can attribute these different patterns of <i>CDR1</i> induction as proceeding through the promoter region of this gene since this is the only segment of the gene included in the luciferase reporter construct. Genetic analysis indicates that the signaling pathways responsible for phenothiazine and azole induction of <i>CDR1</i> overlap but are not identical. The short time course of phenothiazine induction suggests that these compounds may act more directly on the Pdr1 protein to stimulate its activity.</p><p><strong>Importance: </strong><i>Candida glabrata</i> has emerged as the second-leading cause of candidiasis due, in part, to its ability to acquire high-level resistance to azole drugs, a major class of antifungal that acts to block the biosynthesis of the fungal sterol ergosterol. The presence of azole drugs causes the induction of a variety of genes involved in controlling susceptibility to this drug class, including drug transporters and ergosterol biosynthetic genes such as ERG11. We found that the presence of azole drugs leads to an induction of genes encoding drug transporters and ERG11, while exposure of <i>C. glabrata</i> cells to antifungals of the phenothiazine class of drugs caused a much faster and larger induction of drug transporters but not ERG11. Coupled with further genetic analyses of the effects of azole and phenothiazine drugs, our data indicate that these compounds are sensed and responded to differentially in the yeast cell.</p>","PeriodicalId":19052,"journal":{"name":"mSphere","volume":" ","pages":"e0079224"},"PeriodicalIF":3.7,"publicationDate":"2024-11-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142648474","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Astragalus polysaccharide enhances maternal mucosal immunity against PEDV. 黄芪多糖可增强母体黏膜对 PEDV 的免疫力。
IF 3.7 2区 生物学 Q2 MICROBIOLOGY Pub Date : 2024-11-14 DOI: 10.1128/msphere.00777-24
Jianli Tang, Shuaiyong Wang, Jianmei Tang, Jinming Li

Porcine epidemic diarrhea virus (PEDV), the major causative pathogen of porcine epidemic diarrhea, poses a severe threat to the swine industry, particularly affecting neonatal piglets. Maternal milk-derived IgA antibody is crucial for protecting piglets from PEDV infection. Despite the effectiveness of current intramuscularly administered PEDV vaccines in inducing strong systemic immune responses, their ability to generate high levels of maternal milk IgA is limited. This study explores the potential of Astragalus polysaccharide (APS) to enhance PEDV vaccine efficacy, specifically focusing on maternal milk IgA levels. We first evaluated anti-PEDV antibody levels in the blood and colostrum of sows vaccinated with PEDV or subjected to feedback feeding. Our results indicated that while vaccination induced robust serum PEDV-specific IgG and IgA, milk IgA levels were lower compared to the feedback group. To address this limitation, APS was administered orally to sows before PEDV vaccination. APS supplementation significantly increased both serum and milk PEDV-specific IgA levels and enhanced cellular immune responses, as evidenced by elevated cytokine levels. Further analysis demonstrated that APS improved intestinal immune function and homeostasis in piglets. Overall, APS supplementation proved to be an effective immune booster, enhancing PEDV vaccine-induced mucosal immunity and providing a promising strategy for improving maternal immunity and piglet protection against PEDV.

Importance: This study highlights the limitations of current porcine epidemic diarrhea virus (PEDV) vaccines in inducing sufficient maternal milk IgA, which is crucial for protecting neonatal piglets. By supplementing Astragalus polysaccharide (APS) into the vaccination regimen, we demonstrated a significant enhancement in milk PEDV-specific IgA levels, as well as improved cellular immune responses. APS also bolstered intestinal immune function and homeostasis in piglets. These findings suggest that APS supplementation could serve as an immune booster to enhance maternal immunity, offering a promising approach to better protect piglets against PEDV.

猪流行性腹泻病毒(PEDV)是猪流行性腹泻的主要病原体,对养猪业构成严重威胁,尤其影响新生仔猪。母乳中的 IgA 抗体对保护仔猪免受 PEDV 感染至关重要。尽管目前肌肉注射的 PEDV 疫苗能有效诱导强烈的全身免疫反应,但它们产生高水平母乳 IgA 的能力有限。本研究探讨了黄芪多糖(APS)提高 PEDV 疫苗疗效的潜力,尤其关注母体乳汁 IgA 水平。我们首先评估了接种 PEDV 疫苗或进行反馈饲喂的母猪血液和初乳中的抗 PEDV 抗体水平。我们的结果表明,虽然接种疫苗可诱导强效的血清 PEDV 特异性 IgG 和 IgA,但与反馈组相比,母乳中的 IgA 水平较低。为了解决这个问题,我们在注射 PEDV 疫苗前给母猪口服了 APS。补充 APS 后,血清和乳汁中的 PEDV 特异性 IgA 水平均明显提高,细胞因子水平升高也证明了这一点。进一步的分析表明,APS 改善了仔猪的肠道免疫功能和平衡。总之,补充 APS 被证明是一种有效的免疫增强剂,可增强 PEDV 疫苗诱导的粘膜免疫,为提高母体免疫力和仔猪对 PEDV 的保护提供了一种有前途的策略:本研究强调了当前猪流行性腹泻病毒(PEDV)疫苗在诱导足够的母乳 IgA 方面的局限性,而母乳 IgA 对保护新生仔猪至关重要。通过在疫苗接种方案中添加黄芪多糖(APS),我们证明了乳汁中 PEDV 特异性 IgA 水平的显著提高以及细胞免疫反应的改善。APS 还能增强仔猪的肠道免疫功能和平衡。这些研究结果表明,补充 APS 可作为增强母体免疫力的免疫增强剂,为更好地保护仔猪免受 PEDV 感染提供了一种可行的方法。
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引用次数: 0
Exploring the genomic basis of Mpox virus-host transmission and pathogenesis. 探索 Mpox 病毒-宿主传播和致病的基因组基础。
IF 3.7 2区 生物学 Q2 MICROBIOLOGY Pub Date : 2024-11-14 DOI: 10.1128/msphere.00576-24
Brayden Young, Stephanie N Seifert, Crystal Lawson, Heather Koehler

Mpox disease, caused by the monkeypox virus (MPXV), was recently classified as a public health emergency of international concern due to its high lethality and pandemic potential. MPXV is a zoonotic disease that emerged and is primarily spread by small rodents. Historically, it was considered mainly zoonotic and not likely to sustain human-to-human transmission. However, the worldwide outbreak of Clade IIb MPXV from 2020 to 2022 and ongoing Clade I MPXV epidemics in the Democratic Republic of the Congo and surrounding areas are a warning that human-adapted MPXVs will continually arise. Understanding the viral genetic determinants of host range, pathogenesis, and immune evasion is imperative for developing control strategies and predicting the future of Mpox. Here, we delve into the MPXV genome to detail genes involved in host immune evasion strategies for this zoonotic rodent-borne and human-circulating virus. We compare MPXV gene content to related Orthopoxviruses, which have narrow host ranges, to identify potential genes involved in species-specific pathogenesis and host tropism. In addition, we cover the key virulence factor differences that distinguish the MPXV clade lineages. Finally, we dissect how genomic reduction of Orthopoxviruses, through various molecular mechanisms, is contributing to the generation of novel MPXV lineages with increased human adaptation. This review aims to highlight gene content that defines the MPXV species, MPXV clades, and novel MPXV lineages that have culminated in this virus being elevated to a public health emergency of national concern.

由猴痘病毒(MPXV)引起的猴痘病最近被列为国际关注的突发公共卫生事件,因为它具有高致死率和大流行的可能性。MPXV 是一种人畜共患病,主要通过小型啮齿动物出现和传播。一直以来,人们认为它主要是人畜共患疾病,不太可能持续在人与人之间传播。然而,2020 年至 2022 年在全球范围内爆发的克隆 IIb 型 MPXV 和正在刚果民主共和国及周边地区流行的克隆 I 型 MPXV 都在警示人们,适应人类的 MPXV 将不断出现。了解宿主范围、致病机理和免疫逃避的病毒基因决定因素对于制定控制策略和预测 Mpox 的未来至关重要。在此,我们深入研究了 MPXV 的基因组,以详细了解这种人畜共患的啮齿动物传播和人类传播病毒的宿主免疫逃避策略所涉及的基因。我们将 MPXV 的基因含量与宿主范围较窄的相关正索痘病毒进行了比较,以确定参与物种特异性致病和宿主趋性的潜在基因。此外,我们还介绍了区分 MPXV 支系的关键毒力因子差异。最后,我们还剖析了正索痘病毒基因组的减少是如何通过各种分子机制促使产生对人类适应性更强的新型 MPXV 支系的。本综述旨在强调界定 MPXV 种类、MPXV 支系和新型 MPXV 系的基因内容,这些基因内容最终导致该病毒被提升为国家关注的公共卫生紧急事件。
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引用次数: 0
Recombinant chimeric horsepox virus (TNX-801) is attenuated relative to vaccinia virus strains in both in vitro and in vivo models. 重组嵌合型马痘病毒(TNX-801)在体外和体内模型中都比疫苗病毒株减毒。
IF 3.7 2区 生物学 Q2 MICROBIOLOGY Pub Date : 2024-11-13 DOI: 10.1128/msphere.00265-24
Stephanie V Trefry, Mayanka Awasthi, Christy N Raney, Amy L Cregger, Chase A Gonzales, Brittney L Layton, Robert N Enamorado, Nelson A Martinez, Deborah S Gohegan, Masoudeh Masoud-Bahnamiri, Jennifer Y Cho, Dawn M Myscofski, Tinoush Moulaei, Natasza E Ziółkowska, Scott J Goebel, Seth Lederman, Sina Bavari, Farooq Nasar

Recombinant chimeric horsepox virus (TNX-801) is a preclinical vaccine in development against mpox and smallpox. In this report, we investigated the potential phenotypic differences in in vitro and in vivo models between TNX-801 and older vaccinia virus (VACV)-based vaccine strains (VACV-Lis and VACV-NYCBH) used in the eradication of smallpox as well as VACV-WR, VACV-IHD, and MVA. TNX-801 displayed a small plaque phenotype (~1-2 mm) in BSC-40 and Vero-E6 cells. Multi-step replication kinetics in immortalized nonhuman primate cell lines, and human primary cells from dermal and respiratory tracts yielded >10- to 100-fold lower infectious titers than the VACV strains. In addition, the infectious particle-to-genome copy ratio data suggests that TNX-801 genome packaging is ~10- to 100-fold less efficient than the VACV strains and the potential mechanism of TNX-801 attenuation is at the packaging/egress stage. Lastly, the susceptibility to VACV and TNX-801 infection of three new immunocompromised murine models (C56BL/6 Ifnar-/-, C56BL/6 Ifngr-/-, and C56BL/6 Ifnar-/-/Ifngr-/-) was investigated. VACV strains were able to produce severe disease including decrease in body weight and temperature, as well as lethality in murine models via the intraperitoneal or intranasal routes. In contrast to VACV strains, TNX-801 was unable to produce any disease in murine models. These data demonstrate that TNX-801 is >10- to 1,000-fold more attenuated compared to older VACV-based smallpox vaccine strains in human primary cell lines and immunocompromised mice.

Importance: Variola and monkeypox viruses are medically important pathogens that can cause fatal human disease. The two FDA-approved vaccines, ACAM-2000 and JYNNEOS, have important advantages and disadvantages. ACAM-2000 offers durable immunity; however, it has high adverse event rates. In contrast, JYNNEOS has a safer profile but requires two doses 4-weeks apart to achieve comparable immunity. Consequently, there is a need for vaccines offering durable immunity via single immunization with minimal adverse events. TNX-801 is a preclinical stage vaccine that can stimulate potent immunity via a single dose and provides protection against lethal mpox disease in the nonhuman primate model. Here, we show that TNX-801 is >10- to 1,000-fold attenuated in in vitro and in vivo models including human primary cells and immunocompromised murine models than vaccine strains utilized in smallpox eradication. The natural attenuation of TNX-801 and its ability to induce protective immunity via a single vaccination are promising and warrants further development.

重组嵌合马痘病毒(TNX-801)是一种正在开发的临床前疫苗,用于预防水痘和天花。在本报告中,我们研究了 TNX-801 与以前用于根除天花的疫苗株(VACV-Lis 和 VACV-NYCBH)以及 VACV-WR、VACV-IHD 和 MVA 在体外和体内模型中的潜在表型差异。TNX-801 在 BSC-40 和 Vero-E6 细胞中显示出小斑块表型(约 1-2 毫米)。在永生化的非人灵长类细胞系以及来自皮肤和呼吸道的人类原代细胞中,多步复制动力学产生的感染滴度比 VACV 株系低 10 到 100 倍。此外,感染性颗粒与基因组拷贝比数据表明,TNX-801基因组包装的效率比VACV毒株低10至100倍,TNX-801衰减的潜在机制是在包装/表达阶段。最后,研究了三种新的免疫受损小鼠模型(C56BL/6 Ifnar-/-、C56BL/6 Ifngr-/-和C56BL/6 Ifnar-/-/Ifngr-/-)对 VACV 和 TNX-801 感染的易感性。VACV 株系能够通过腹腔或鼻内途径在小鼠模型中产生严重疾病,包括体重和体温下降以及致死。与 VACV 株系相反,TNX-801 无法在小鼠模型中产生任何疾病。这些数据表明,在人类原代细胞系和免疫功能低下的小鼠中,TNX-801 的减毒效果比基于 VACV 的旧天花疫苗株高出 10 至 1000 倍:重要意义: 天花和猴痘病毒是医学上重要的病原体,可导致致命的人类疾病。美国食品及药物管理局批准的两种疫苗--ACAM-2000 和 JYNNEOS--各有重要的优缺点。ACAM-2000 可提供持久免疫力,但不良反应率较高。相比之下,JYNNEOS 的安全性更高,但需要间隔 4 周注射两剂才能获得类似的免疫力。因此,需要通过单次免疫获得持久免疫力且不良反应最小的疫苗。TNX-801 是一种处于临床前阶段的疫苗,可通过单次剂量激发强大的免疫力,并在非人灵长类动物模型中提供对致命性 mpox 疾病的保护。在这里,我们展示了 TNX-801 在体外和体内模型(包括人类原代细胞和免疫力低下的小鼠模型)中的减毒效果,与根除天花时使用的疫苗株相比,TNX-801 的减毒效果>10-1000 倍。TNX-801 的自然减毒能力及其通过单次接种诱导保护性免疫的能力前景广阔,值得进一步开发。
{"title":"Recombinant chimeric horsepox virus (TNX-801) is attenuated relative to vaccinia virus strains in both <i>in vitro</i> and <i>in vivo</i> models.","authors":"Stephanie V Trefry, Mayanka Awasthi, Christy N Raney, Amy L Cregger, Chase A Gonzales, Brittney L Layton, Robert N Enamorado, Nelson A Martinez, Deborah S Gohegan, Masoudeh Masoud-Bahnamiri, Jennifer Y Cho, Dawn M Myscofski, Tinoush Moulaei, Natasza E Ziółkowska, Scott J Goebel, Seth Lederman, Sina Bavari, Farooq Nasar","doi":"10.1128/msphere.00265-24","DOIUrl":"https://doi.org/10.1128/msphere.00265-24","url":null,"abstract":"<p><p>Recombinant chimeric horsepox virus (TNX-801) is a preclinical vaccine in development against mpox and smallpox. In this report, we investigated the potential phenotypic differences in <i>in vitro</i> and <i>in vivo</i> models between TNX-801 and older vaccinia virus (VACV)-based vaccine strains (VACV-Lis and VACV-NYCBH) used in the eradication of smallpox as well as VACV-WR, VACV-IHD, and MVA. TNX-801 displayed a small plaque phenotype (~1-2 mm) in BSC-40 and Vero-E6 cells. Multi-step replication kinetics in immortalized nonhuman primate cell lines, and human primary cells from dermal and respiratory tracts yielded >10- to 100-fold lower infectious titers than the VACV strains. In addition, the infectious particle-to-genome copy ratio data suggests that TNX-801 genome packaging is ~10- to 100-fold less efficient than the VACV strains and the potential mechanism of TNX-801 attenuation is at the packaging/egress stage. Lastly, the susceptibility to VACV and TNX-801 infection of three new immunocompromised murine models (C56BL/6 <i>Ifnar</i><sup>-/-</sup>, C56BL/6 <i>Ifngr</i><sup>-/-</sup>, and C56BL/6 <i>Ifnar</i><sup>-/-</sup>/<i>Ifngr</i><sup>-/-</sup>) was investigated. VACV strains were able to produce severe disease including decrease in body weight and temperature, as well as lethality in murine models via the intraperitoneal or intranasal routes. In contrast to VACV strains, TNX-801 was unable to produce any disease in murine models. These data demonstrate that TNX-801 is >10- to 1,000-fold more attenuated compared to older VACV-based smallpox vaccine strains in human primary cell lines and immunocompromised mice.</p><p><strong>Importance: </strong>Variola and monkeypox viruses are medically important pathogens that can cause fatal human disease. The two FDA-approved vaccines, ACAM-2000 and JYNNEOS, have important advantages and disadvantages. ACAM-2000 offers durable immunity; however, it has high adverse event rates. In contrast, JYNNEOS has a safer profile but requires two doses 4-weeks apart to achieve comparable immunity. Consequently, there is a need for vaccines offering durable immunity via single immunization with minimal adverse events. TNX-801 is a preclinical stage vaccine that can stimulate potent immunity via a single dose and provides protection against lethal mpox disease in the nonhuman primate model. Here, we show that TNX-801 is >10- to 1,000-fold attenuated in <i>in vitro</i> and <i>in vivo</i> models including human primary cells and immunocompromised murine models than vaccine strains utilized in smallpox eradication. The natural attenuation of TNX-801 and its ability to induce protective immunity via a single vaccination are promising and warrants further development.</p>","PeriodicalId":19052,"journal":{"name":"mSphere","volume":" ","pages":"e0026524"},"PeriodicalIF":3.7,"publicationDate":"2024-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142624746","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Comparative genomics of obligate predatory bacteria belonging to phylum Bdellovibrionota highlights distribution and predicted functions of lineage-specific protein families. 属于 Bdellovibrionota 门的强制性捕食细菌的比较基因组学突显了特定品系蛋白质家族的分布和预测功能。
IF 3.7 2区 生物学 Q2 MICROBIOLOGY Pub Date : 2024-11-13 DOI: 10.1128/msphere.00680-24
Sidney C Davis, Joseph Cerra, Laura E Williams

Comparative genomics of predatory bacteria is important to understand their ecology and evolution and explore their potential to treat drug-resistant infections. We compared chromosomes of 18 obligate predators from phylum Bdellovibrionota (16 intraperiplasmic, two epibiotic) and 15 non-predatory bacteria. Phylogenetics of conserved single-copy genes and analysis of genome-wide average amino acid identity provide evidence for at least five Bdellovibrio species and support recent reclassifications of predatory taxa. To define shared and differential genome content, we grouped predicted protein sequences into gene clusters based on sequence similarity. Few gene clusters are shared by all 33 bacteria or all 18 predatory bacteria; however, we identified gene clusters conserved within lineages, such as intraperiplasmic Bdellovibrio, and not found in other bacteria. Many of these are predicted to function in cell envelope biogenesis, signal transduction, and other roles important for predatory lifestyles. Among intraperiplasmic Bdellovibrio, we detected high abundance of gene clusters predicted to encode transglycosylases, endopeptidases, and lysozymes, and we identified six gene clusters (amidase, L,D-transpeptidase, four transglycosylases) with evidence of recent gene duplication and gene family expansion. Focusing on peptidoglycan metabolism, we defined a suite of gene clusters that include peptidoglycan-degrading and -modifying enzymes and occur only in predatory bacteria, suggesting these proteins may have evolved activities specific to predation. Our analyses highlight key genome content differences between obligate predatory bacteria and non-predatory relatives and identify gene clusters that may encode enzymes adapted to predatory lifestyles. These lineage-specific proteins are strong candidates for functional characterization to clarify their role in predation.IMPORTANCEEvolution of predation as a bacterial lifestyle involves selective pressure on and adaptation of enzymes that contribute to killing and digestion of prey bacteria, in some cases from within the prey itself. Such enzymes are a hallmark of obligate predatory bacteria belonging to phylum Bdellovibrionota, which includes the well-studied predator Bdellovibrio. By comparing protein sequences of obligate predatory bacteria and their non-predatory relatives, we define key genome content differences that distinguish bacterial predators and identify lineage-specific enzymes that may have evolved unique activities due to selective pressures related to a predatory lifestyle. In addition to providing insights into the ecology and evolution of predatory bacteria, comparative genomics studies, like this, can inform efforts to develop predatory bacteria and/or their enzymes as potential biocontrol agents to combat drug-resistant bacterial infections.

食肉细菌的比较基因组学对于了解其生态学和进化以及探索其治疗耐药性感染的潜力非常重要。我们比较了 Bdellovibrionota 门 18 种必须捕食细菌(16 种质粒内捕食细菌,2 种外捕食细菌)和 15 种非捕食细菌的染色体。保守单拷贝基因的系统发生学和全基因组平均氨基酸同一性分析提供了至少 5 种 Bdellovibrio 的证据,并支持了最近对掠食性类群的重新分类。为了确定共享和差异基因组内容,我们根据序列相似性将预测的蛋白质序列归入基因簇。所有 33 种细菌或所有 18 种捕食性细菌共享的基因簇很少;但是,我们发现了一些在各系(如质内双胞杆菌)中保守的基因簇,而这些基因簇在其他细菌中并不存在。其中许多基因被认为具有细胞膜生物发生、信号转导和其他对掠食性生活方式很重要的功能。在质膜内布氏嗜血杆菌中,我们发现了高丰度的基因簇,这些基因簇被预测为编码转糖苷酶、内肽酶和溶菌酶,我们还发现了六个基因簇(酰胺酶、L,D-转肽酶、四个转糖苷酶),这些基因簇都有近期基因复制和基因家族扩展的证据。以肽聚糖代谢为重点,我们定义了一套基因簇,其中包括肽聚糖降解酶和修饰酶,而且只出现在捕食性细菌中,这表明这些蛋白质可能进化出了捕食性细菌特有的活动。我们的分析突显了强制性捕食细菌与非捕食性近缘细菌之间的关键基因组内容差异,并确定了可能编码适应捕食性生活方式的酶的基因簇。重要意义捕食作为一种细菌生活方式的进化涉及对有助于杀死和消化猎物细菌的酶的选择性压力和适应,在某些情况下,这些酶来自猎物本身。这种酶是属于细菌门(Bdellovibrionota)的强制性捕食细菌的标志,其中包括研究得很清楚的捕食者 Bdellovibrio。通过比较强制性捕食细菌及其非捕食性近亲的蛋白质序列,我们确定了区别细菌捕食者的关键基因组内容差异,并鉴定了可能由于与捕食性生活方式相关的选择性压力而进化出独特活性的特异性酶。除了为捕食性细菌的生态学和进化提供见解之外,类似的比较基因组学研究还能为开发捕食性细菌和/或其酶作为潜在生物控制剂以对抗耐药性细菌感染提供信息。
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