scholarly journals Scale‐up of a Type I secretion system in E. coli using a defined mineral medium

2020 ◽  
Vol 36 (2) ◽  
Author(s):  
Nina Ihling ◽  
Andreas Uhde ◽  
Romy Scholz ◽  
Christian Schwarz ◽  
Lutz Schmitt ◽  
...  

2020 ◽  
Author(s):  
Christopher Icke ◽  
Freya J. Hodges ◽  
Karthik Puella ◽  
Samantha A. McKeand ◽  
Jack A. Bryant ◽  
...  

AbstractProtein acylation is critical for many cellular functions including signal transduction, cell division and development. In bacteria, such lipoproteins have important roles in virulence and are therefore potential targets for the development of novel antimicrobials and vaccines. To date, all known bacterial lipoproteins are secreted from the cytosol via the Sec pathway, acylated on an N-terminal cysteine residue through the action of Lgt, Lsp and Lnt, and then targeted to the appropriate cellular location. In the case of Gram-negative bacteria, the lipoprotein trafficking Lol pathway transports the lipoproteins to the outer membrane where most substrate molecules are retained within the cell. Here we identify a new secretion pathway that displays the substrate lipoprotein on the cell surface. We demonstrate that the previously identified E. coli Aat secretion system is a composite system that shares similarity with type I secretion systems and elements of the Lol pathway. Remarkably, during secretion by the Aat system, the AatD subunit acylates the substrate CexE on a highly conserved N-terminal glycine residue (rather than the canonical cysteine). Mutations in AatD or CexE that disrupt glycine acylation interfere with membrane incorporation and trafficking. Our data suggest that CexE is the first member of a new class of glycine-acylated bacterial lipoprotein, while Aat represents a new secretion system that we propose be defined as a lipoprotein secretion system (LSS).



2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Abinaya Badri ◽  
Asher Williams ◽  
Adeola Awofiranye ◽  
Payel Datta ◽  
Ke Xia ◽  
...  

AbstractSulfated glycosaminoglycans (GAGs) are a class of important biologics that are currently manufactured by extraction from animal tissues. Although such methods are unsustainable and prone to contamination, animal-free production methods have not emerged as competitive alternatives due to complexities in scale-up, requirement for multiple stages and cost of co-factors and purification. Here, we demonstrate the development of single microbial cell factories capable of complete, one-step biosynthesis of chondroitin sulfate (CS), a type of GAG. We engineer E. coli to produce all three required components for CS production–chondroitin, sulfate donor and sulfotransferase. In this way, we achieve intracellular CS production of ~27 μg/g dry-cell-weight with about 96% of the disaccharides sulfated. We further explore four different factors that can affect the sulfation levels of this microbial product. Overall, this is a demonstration of simple, one-step microbial production of a sulfated GAG and marks an important step in the animal-free production of these molecules.



Gene ◽  
1997 ◽  
Vol 191 (2) ◽  
pp. 167-172 ◽  
Author(s):  
Peter Penzes ◽  
Xianshu Wang ◽  
Zuzana Sperkova ◽  
Joseph L Napoli


1991 ◽  
Vol 37 (5) ◽  
pp. 407-410
Author(s):  
Mônica A. M. Vieira ◽  
Beatriz E. C. Guth ◽  
Tânia A. T. Gomes

DNA probes that identify genes coding for heat-labile type I (LT-I) and heat-stable type 1 (ST-I) enterotoxins, enteropathogenic Escherichia coli adherence factor (EAF), and Shigella-like, invasiveness (INV) are used to evaluate the sensitivity and specificity of stool blots in comparison with the sensitivity and specificity of colony blots in detecting enteropathoghens. The sensitivities of the probes in stool blots are 91.7% for the LT-I probe, 76.9% for the ST-I probes, 78.9% for the EAF probe, and 45.5% for the INV probe. The specificity of all probes is higher than 95%. In general, the stool blot method identifies as many if not more LT-I-, ST-I-, and EAF-producing E. coli infections than the colony blots. Key words: DNA probes, stool blots, enteropathogens, diagnosis.



2016 ◽  
Vol 473 (21) ◽  
pp. 3923-3936 ◽  
Author(s):  
Dani Zalem ◽  
João P. Ribeiro ◽  
Annabelle Varrot ◽  
Michael Lebens ◽  
Anne Imberty ◽  
...  

The structurally related AB5-type heat-labile enterotoxins of Escherichia coli and Vibrio cholerae are classified into two major types. The type I group includes cholera toxin (CT) and E. coli LT-I, whereas the type II subfamily comprises LT-IIa, LT-IIb and LT-IIc. The carbohydrate-binding specificities of LT-IIa, LT-IIb and LT-IIc are distinctive from those of cholera toxin and E. coli LT-I. Whereas CT and LT-I bind primarily to the GM1 ganglioside, LT-IIa binds to gangliosides GD1a, GD1b and GM1, LT-IIb binds to the GD1a and GT1b gangliosides, and LT-IIc binds to GM1, GM2, GM3 and GD1a. These previous studies of the binding properties of type II B-subunits have been focused on ganglio core chain gangliosides. To further define the carbohydrate binding specificity of LT-IIb B-subunits, we have investigated its binding to a collection of gangliosides and non-acid glycosphingolipids with different core chains. A high-affinity binding of LT-IIb B-subunits to gangliosides with a neolacto core chain, such as Neu5Gcα3- and Neu5Acα3-neolactohexaosylceramide, and Neu5Gcα3- and Neu5Acα3-neolactooctaosylceramide was detected. An LT-IIb-binding ganglioside was isolated from human small intestine and characterized as Neu5Acα3-neolactohexaosylceramide. The crystal structure of the B-subunit of LT-IIb with the pentasaccharide moiety of Neu5Acα3-neolactotetraosylceramide (Neu5Ac-nLT: Neu5Acα3Galβ4GlcNAcβ3Galβ4Glc) was determined providing the first information for a sialic-binding site in this subfamily, with clear differences from that of CT and LT-I.



2015 ◽  
Vol 11 (9) ◽  
pp. 2464-2472 ◽  
Author(s):  
Dan Coursolle ◽  
Jiazhang Lian ◽  
John Shanklin ◽  
Huimin Zhao

An orthogonal type I FAS was introduced into E. coli to increase the production of long chain alcohols and alkanes.



2007 ◽  
Vol 130 (3) ◽  
pp. 311-315 ◽  
Author(s):  
Jae Kwang Song ◽  
Joon Young Oh ◽  
Gyeong Tae Eom ◽  
Bong Keun Song


2017 ◽  
Vol 84 (1) ◽  
Author(s):  
Sakshi Khosa ◽  
Romy Scholz ◽  
Christian Schwarz ◽  
Mirko Trilling ◽  
Hartmut Hengel ◽  
...  

ABSTRACTEfficient protein secretion is often a valuable alternative to classic cellular expression to obtain homogenous protein samples. Early on, bacterial type I secretion systems (T1SS) were employed to allow heterologous secretion of fusion proteins. However, this approach was not fully exploited, as many proteins could not be secreted at all or only at low levels. Here, we present an engineered microbial secretion system which allows the effective production of proteins up to a molecular mass of 88 kDa. This system is based on the hemolysin A (HlyA) T1SS of the Gram-negative bacteriumEscherichia coli, which exports polypeptides when fused to a hemolysin secretion signal. We identified an A/U-rich enhancer region upstream ofhlyArequired for effective expression and secretion of selected heterologous proteins irrespective of their prokaryotic, viral, or eukaryotic origin. We further demonstrate that the ribosomal protein S1 binds to thehlyAA/U-rich enhancer region and that this region is involved in the high yields of secretion of functional proteins, like maltose-binding protein or human interferon alpha-2.IMPORTANCEA 5′ untranslated region of the mRNA of substrates of type I secretion systems (T1SS) drastically enhanced the secretion efficiency of the endogenously secreted protein. The identification of ribosomal protein S1 as the interaction partner of this 5′ untranslated region provides a rationale for the enhancement. This strategy furthermore can be transferred to fusion proteins allowing a broader, and eventually a more general, application of this system for secreting heterologous fusion proteins.



2021 ◽  
Vol 41 (6) ◽  
pp. 68-70
Author(s):  
Marcel Thön ◽  
Ilona Koebsch
Keyword(s):  


2020 ◽  
Author(s):  
Jake D. Callaghan ◽  
Nicholas A. Stella ◽  
Kara M. Lehner ◽  
Benjamin R. Treat ◽  
Kimberly M. Brothers ◽  
...  

ABSTRACTTunable control of gene expression is an invaluable tool for biological experiments. In this study, we describe a new xylose-inducible promoter system and evaluate it in both Pseudomonas aeruginosa and P. fluorescens. The Pxut promoter derived from the P. flurorescens xut operon was incorporated into a broad host-range pBBR1-based plasmid and compared to the Escherichia coli-derived PBAD promoter using gfp as a reporter. GFP-fluorescence from the Pxut promoter was inducible in both Pseudomonas species, but not in E. coli, which may facilitate cloning of toxic genes using E. coli to generate plasmids. The Pxut promoter was expressed at a lower inducer concentration than PBAD in P. fluorescens and higher gfp levels were achieved using Pxut. Flow cytometry analysis indicated that Pxut was more leaky than PBAD in the tested Pseudomonas species, but was expressed in a higher proportion of cells when induced. D-xylose did not support growth of P. aeruginosa or P. fluorescens as a sole carbon source and is less expensive than many other commonly used inducers which could facilitate large scale applications. The efficacy of this system aided in demonstrating a role for the P. aeruginosa type II secretion system gene from xcpQ in bacterial inhibition of corneal epithelial cell wound closure. This study introduces a new inducible promoter system for gene expression for use in Pseudomonas species.ImportancePseudomonas species are enormously important in human infections, biotechnology, and as a model system for interrogating basic science questions. In this study we have developed a xylose-inducible promoter system and evaluated it in P. aeruginosa and P. fluorescens and found it to be suitable for the strong induction of gene expression. Furthermore, we have demonstrated its efficacy in controlled gene expression to show that a type 2 secretion system protein from P. aeruginosa, XcpQ, is important for host-pathogen interactions in a corneal wound closure model.



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