EcoSal Plus最新文献_第9页

Osmoregulated Periplasmic Glucans. 渗透调节的质周葡聚糖。

EcoSal Plus Pub Date : 2017-06-01 DOI: 10.1128/ecosalplus.ESP-0001-2017

Sébastien Bontemps-Gallo, Jean-Pierre Bohin, Jean-Marie Lacroix

引用次数: 41

Regulation of Escherichia coli Pathogenesis by Alternative Sigma Factor N. 备选Sigma因子N对大肠杆菌发病机制的调控。

EcoSal Plus Pub Date : 2017-06-01 DOI: 10.1128/ecosalplus.ESP-0016-2016

James T Riordan, Avishek Mitra

{"title":"Regulation of Escherichia coli Pathogenesis by Alternative Sigma Factor N.","authors":"James T Riordan, Avishek Mitra","doi":"10.1128/ecosalplus.ESP-0016-2016","DOIUrl":"https://doi.org/10.1128/ecosalplus.ESP-0016-2016","url":null,"abstract":"σN (also σ54) is an alternative sigma factor subunit of the RNA polymerase complex that regulates the expression of genes from many different ontological groups. It is broadly conserved in the Eubacteria with major roles in nitrogen metabolism, membrane biogenesis, and motility. σN is encoded as the first gene of a five-gene operon including rpoN (σN), ptsN, hpf, rapZ, and npr that has been genetically retained among species of Escherichia, Shigella, and Salmonella. In an increasing number of bacteria, σN has been implicated in the control of genes essential to pathogenic behavior, including those involved in adherence, secretion, immune subversion, biofilm formation, toxin production, and resistance to both antimicrobials and biological stressors. For most pathogens how this is achieved is unknown. In enterohemorrhagic Escherichia coli (EHEC) O157, Salmonella enterica, and Borrelia burgdorferi, regulation of virulence by σN requires another alternative sigma factor, σS, yet the model by which σN-σS virulence regulation is predicted to occur is varied in each of these pathogens. In this review, the importance of σN to bacterial pathogenesis is introduced, and common features of σN-dependent virulence regulation discussed. Emphasis is placed on the molecular mechanisms underlying σN virulence regulation in E. coli O157. This includes a review of the structure and function of regulatory pathways connecting σN to virulence expression, predicted input signals for pathway stimulation, and the role for cognate σN activators in initiation of gene systems determining pathogenic behavior.","PeriodicalId":11500,"journal":{"name":"EcoSal Plus","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2017-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1128/ecosalplus.ESP-0016-2016","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"35106722","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 15

The Legacy of Genetic Analysis Advances Contemporary Research with Escherichia coli K-12 and Salmonella enterica serovar Typhimurium LT2. 遗传分析的遗产推进了大肠杆菌K-12和肠沙门氏菌血清型鼠伤寒杆菌LT2的当代研究。

EcoSal Plus Pub Date : 2017-04-01 DOI: 10.1128/ecosalplus.ESP-0014-2016

Valley Stewart

引用次数: 0

Targeting and Insertion of Membrane Proteins. 膜蛋白的靶向与插入。

EcoSal Plus Pub Date : 2017-03-01 DOI: 10.1128/ecosalplus.ESP-0012-2016

Andreas Kuhn, Hans-Georg Koch, Ross E Dalbey

引用次数: 59

Systems Metabolic Engineering of Escherichia coli. 大肠杆菌系统代谢工程。

EcoSal Plus Pub Date : 2017-03-01 DOI: 10.1128/ecosalplus.ESP-0088-2015

Kyeong Rok Choi, Jae Ho Shin, Jae Sung Cho, Dongsoo Yang, Sang Yup Lee

{"title":"Systems Metabolic Engineering of Escherichia coli.","authors":"Kyeong Rok Choi, Jae Ho Shin, Jae Sung Cho, Dongsoo Yang, Sang Yup Lee","doi":"10.1128/ecosalplus.ESP-0088-2015","DOIUrl":"https://doi.org/10.1128/ecosalplus.ESP-0088-2015","url":null,"abstract":"Systems metabolic engineering, which recently emerged as metabolic engineering integrated with systems biology, synthetic biology, and evolutionary engineering, allows engineering of microorganisms on a systemic level for the production of valuable chemicals far beyond its native capabilities. Here, we review the strategies for systems metabolic engineering and particularly its applications in Escherichia coli. First, we cover the various tools developed for genetic manipulation in E. coli to increase the production titers of desired chemicals. Next, we detail the strategies for systems metabolic engineering in E. coli, covering the engineering of the native metabolism, the expansion of metabolism with synthetic pathways, and the process engineering aspects undertaken to achieve higher production titers of desired chemicals. Finally, we examine a couple of notable products as case studies produced in E. coli strains developed by systems metabolic engineering. The large portfolio of chemical products successfully produced by engineered E. coli listed here demonstrates the sheer capacity of what can be envisioned and achieved with respect to microbial production of chemicals. Systems metabolic engineering is no longer in its infancy; it is now widely employed and is also positioned to further embrace next-generation interdisciplinary principles and innovation for its upgrade. Systems metabolic engineering will play increasingly important roles in developing industrial strains including E. coli that are capable of efficiently producing natural and nonnatural chemicals and materials from renewable nonfood biomass.","PeriodicalId":11500,"journal":{"name":"EcoSal Plus","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2017-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"34801437","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 24

Type I Protein Secretion-Deceptively Simple yet with a Wide Range of Mechanistic Variability across the Family. I型蛋白分泌-看似简单，但在整个家族中具有广泛的机械变异性。

EcoSal Plus Pub Date : 2016-12-13 DOI: 10.1128/ecosalplus.ESP-0019-2015

I. Holland, S. Peherstorfer, Kerstin Kanonenberg, Michael H. H. Lenders, S. Reimann, L. Schmitt

{"title":"Type I Protein Secretion-Deceptively Simple yet with a Wide Range of Mechanistic Variability across the Family.","authors":"I. Holland, S. Peherstorfer, Kerstin Kanonenberg, Michael H. H. Lenders, S. Reimann, L. Schmitt","doi":"10.1128/ecosalplus.ESP-0019-2015","DOIUrl":"https://doi.org/10.1128/ecosalplus.ESP-0019-2015","url":null,"abstract":"A very large type I polypeptide begins to reel out from a ribosome; minutes later, the still unidentifiable polypeptide, largely lacking secondary structure, is now in some cases a thousand or more residues longer. Synthesis of the final hundred C-terminal residues commences. This includes the identity code, the secretion signal within the last 50 amino acids, designed to dock with a waiting ATP binding cassette (ABC) transporter. What happens next is the subject of this review, with the main, but not the only focus on hemolysin HlyA, an RTX protein toxin secreted by the type I system. Transport substrates range from small peptides to giant proteins produced by many pathogens. These molecules, without detectable cellular chaperones, overcome enormous barriers, crossing two membranes before final folding on the cell surface, involving a unique autocatalytic process.Unfolded HlyA is extruded posttranslationally, C-terminal first. The transenvelope \"tunnel\" is formed by HlyB (ABC transporter), HlyD (membrane fusion protein) straddling the inner membrane and periplasm and TolC (outer membrane). We present a new evaluation of the C-terminal secretion code, and the structure function of HlyD and HlyB at the heart of this nanomachine. Surprisingly, key details of the secretion mechanism are remarkably variable in the many type I secretion system subtypes. These include alternative folding processes, an apparently distinctive secretion code for each type I subfamily, and alternative forms of the ABC transporter; most remarkably, the ABC protein probably transports peptides or polypeptides by quite different mechanisms. Finally, we suggest a putative structure for the Hly-translocon, HlyB, the multijointed HlyD, and the TolC exit.","PeriodicalId":11500,"journal":{"name":"EcoSal Plus","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2016-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1128/ecosalplus.ESP-0019-2015","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"64031511","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 39

Live Attenuated Human Salmonella Vaccine Candidates: Tracking the Pathogen in Natural Infection and Stimulation of Host Immunity. 人类沙门氏菌减毒活疫苗候选者：追踪自然感染中的病原体并刺激宿主免疫。

EcoSal Plus Pub Date : 2016-11-01 DOI: 10.1128/ecosalplus.ESP-0010-2016

James E Galen, Amanda D Buskirk, Sharon M Tennant, Marcela F Pasetti

{"title":"Live Attenuated Human Salmonella Vaccine Candidates: Tracking the Pathogen in Natural Infection and Stimulation of Host Immunity.","authors":"James E Galen, Amanda D Buskirk, Sharon M Tennant, Marcela F Pasetti","doi":"10.1128/ecosalplus.ESP-0010-2016","DOIUrl":"10.1128/ecosalplus.ESP-0010-2016","url":null,"abstract":"Salmonellosis, caused by members of the genus Salmonella, is responsible for considerable global morbidity and mortality in both animals and humans. In this review, we will discuss the pathogenesis of Salmonella enterica serovar Typhi and Salmonella enterica serovar Typhimurium, focusing on human Salmonella infections. We will trace the path of Salmonella through the body, including host entry sites, tissues and organs affected, and mechanisms involved in both pathogenesis and stimulation of host immunity. Careful consideration of the natural progression of disease provides an important context in which attenuated live oral vaccines can be rationally designed and developed. With this in mind, we will describe a series of attenuated live oral vaccines that have been successfully tested in clinical trials and demonstrated to be both safe and highly immunogenic. The attenuation strategies summarized in this review offer important insights into further development of attenuated vaccines against other Salmonella for which live oral candidates are currently unavailable.","PeriodicalId":11500,"journal":{"name":"EcoSal Plus","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2016-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5119766/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"64031447","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Anaerobic Formate and Hydrogen Metabolism. 厌氧甲酸与氢代谢。

EcoSal Plus Pub Date : 2016-10-04 DOI: 10.1128/ecosalplus.ESP-0011-2016

R. Sawers, M. Blokesch, August Böck

{"title":"Anaerobic Formate and Hydrogen Metabolism.","authors":"R. Sawers, M. Blokesch, August Böck","doi":"10.1128/ecosalplus.ESP-0011-2016","DOIUrl":"https://doi.org/10.1128/ecosalplus.ESP-0011-2016","url":null,"abstract":"Numerous recent developments in the biochemistry, molecular biology, and physiology of formate and H2 metabolism and of the [NiFe]-hydrogenase (Hyd) cofactor biosynthetic machinery are highlighted. Formate export and import by the aquaporin-like pentameric formate channel FocA is governed by interaction with pyruvate formate-lyase, the enzyme that generates formate. Formate is disproportionated by the reversible formate hydrogenlyase (FHL) complex, which has been isolated, allowing biochemical dissection of evolutionary parallels with complex I of the respiratory chain. A recently identified sulfido-ligand attached to Mo in the active site of formate dehydrogenases led to the proposal of a modified catalytic mechanism. Structural analysis of the homologous, H2-oxidizing Hyd-1 and Hyd-5 identified a novel proximal [4Fe-3S] cluster in the small subunit involved in conferring oxygen tolerance to the enzymes. Synthesis of Salmonella Typhimurium Hyd-5 occurs aerobically, which is novel for an enterobacterial Hyd. The O2-sensitive Hyd-2 enzyme has been shown to be reversible: it presumably acts as a conformational proton pump in the H2-oxidizing mode and is capable of coupling reverse electron transport to drive H2 release. The structural characterization of all the Hyp maturation proteins has given new impulse to studies on the biosynthesis of the Fe(CN)2CO moiety of the [NiFe] cofactor. It is synthesized on a Hyp-scaffold complex, mainly comprising HypC and HypD, before insertion into the apo-large subunit. Finally, clear evidence now exists indicating that Escherichia coli can mature Hyd enzymes differentially, depending on metal ion availability and the prevailing metabolic state. Notably, Hyd-3 of the FHL complex takes precedence over the H2-oxidizing enzymes.","PeriodicalId":11500,"journal":{"name":"EcoSal Plus","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2016-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1128/ecosalplus.ESP-0011-2016","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"64031529","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 67

Animal Enterotoxigenic Escherichia coli. 动物肠毒性大肠杆菌。

EcoSal Plus Pub Date : 2016-10-01 DOI: 10.1128/ecosalplus.ESP-0006-2016

J Daniel Dubreuil, Richard E Isaacson, Dieter M Schifferli

{"title":"Animal Enterotoxigenic Escherichia coli.","authors":"J Daniel Dubreuil, Richard E Isaacson, Dieter M Schifferli","doi":"10.1128/ecosalplus.ESP-0006-2016","DOIUrl":"10.1128/ecosalplus.ESP-0006-2016","url":null,"abstract":"Enterotoxigenic Escherichia coli (ETEC) is the most common cause of E. coli diarrhea in farm animals. ETEC are characterized by the ability to produce two types of virulence factors: adhesins that promote binding to specific enterocyte receptors for intestinal colonization and enterotoxins responsible for fluid secretion. The best-characterized adhesins are expressed in the context of fimbriae, such as the F4 (also designated K88), F5 (K99), F6 (987P), F17, and F18 fimbriae. Once established in the animal small intestine, ETEC produce enterotoxin(s) that lead to diarrhea. The enterotoxins belong to two major classes: heat-labile toxins that consist of one active and five binding subunits (LT), and heat-stable toxins that are small polypeptides (STa, STb, and EAST1). This review describes the disease and pathogenesis of animal ETEC, the corresponding virulence genes and protein products of these bacteria, their regulation and targets in animal hosts, as well as mechanisms of action. Furthermore, vaccines, inhibitors, probiotics, and the identification of potential new targets by genomics are presented in the context of animal ETEC.","PeriodicalId":11500,"journal":{"name":"EcoSal Plus","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2016-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5123703/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"64031821","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","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 Mosaic Type IV Secretion Systems. 马赛克IV型分泌系统。

EcoSal Plus Pub Date : 2016-08-04 DOI: 10.1128/ecosalplus.ESP-0020-2015

P. Christie

{"title":"The Mosaic Type IV Secretion Systems.","authors":"P. Christie","doi":"10.1128/ecosalplus.ESP-0020-2015","DOIUrl":"https://doi.org/10.1128/ecosalplus.ESP-0020-2015","url":null,"abstract":"Escherichia coli and other Gram-negative and -positive bacteria employ type IV secretion systems (T4SSs) to translocate DNA and protein substrates, generally by contact-dependent mechanisms, to other cells. The T4SSs functionally encompass two major subfamilies, the conjugation systems and the effector translocators. The conjugation systems are responsible for interbacterial transfer of antibiotic resistance genes, virulence determinants, and genes encoding other traits of potential benefit to the bacterial host. The effector translocators are used by many Gram-negative pathogens for delivery of potentially hundreds of virulence proteins termed effectors to eukaryotic cells during infection. In E. coli and other species of Enterobacteriaceae, T4SSs identified to date function exclusively in conjugative DNA transfer. In these species, the plasmid-encoded systems can be classified as the P, F, and I types. The P-type systems are the simplest in terms of subunit composition and architecture, and members of this subfamily share features in common with the paradigmatic Agrobacterium tumefaciens VirB/VirD4 T4SS. This review will summarize our current knowledge of the E. coli systems and the A. tumefaciens P-type system, with emphasis on the structural diversity of the T4SSs. Ancestral P-, F-, and I-type systems were adapted throughout evolution to yield the extant effector translocators, and information about well-characterized effector translocators also is included to further illustrate the adaptive and mosaic nature of these highly versatile machines.","PeriodicalId":11500,"journal":{"name":"EcoSal Plus","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2016-08-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1128/ecosalplus.ESP-0020-2015","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"64031609","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 109