Characterization of uropathogenic E. coli O25b‐B2‐ST131, O15:K52:H1, and CGA: Neutrophils apoptosis, serum bactericidal assay, biofilm formation, and virulence typing

2019 ◽  
Vol 234 (10) ◽  
pp. 18272-18282 ◽  
Author(s):  
Seyyed Khalil Shokouhi Mostafavi ◽  
Shahin Najar‐Peerayeh ◽  
Ashraf Mohabbati Mobarez ◽  
Mehdi Kardoust Parizi
Keyword(s):  
Biofilm Formation ◽  
E Coli ◽  
Bactericidal Assay ◽  
Serum Bactericidal Assay ◽  
Neutrophils Apoptosis ◽  
Virulence Typing

scholarly journals Truncation of poly-N-acetylglucosamine (PNAG) polymerization with N-acetylglucosamine analogues

2021 ◽  
Author(s):  
Zachary Morrison ◽  
Alexander Eddenden ◽  
Adithya S Subramanian ◽  
P. Lynne Howell ◽  
mark nitz
Keyword(s):  
Biofilm Formation ◽  
Chain Termination ◽  
Salvage Pathway ◽  
Biofilm Inhibition ◽  
E Coli ◽  
Substrate Analogues

Bacteria require polysaccharides for structure, survival, and virulence. Despite the central role these structures play in microbiology few tools are available to manipulate their production. In E. coli the glycosyltransferase complex PgaCD produces poly-N-acetylglucosamine (PNAG), an extracellular matrix polysaccharide required for biofilm formation. We report that C6-substituted (H, F, N3, SH, NH2) UDP-GlcNAc substrate analogues are inhibitors of PgaCD. In vitro the inhibitors cause PNAG chain termination; consistent with the mechanism of PNAG polymerization from the non-reducing terminus. In vivo, expression of the GlcNAc-1-kinase NahK in E. coli provided a non-native GlcNAc salvage pathway that produced the UDP-GlcNAc analogue inhibitors in situ. The 6-fluoro and 6-deoxy derivatives were potent inhibitors of biofilm formation in the transformed strain, providing a tool to manipulate this key exopolysaccharide. Characterization of the UDP-GlcNAc pool and quantification of PNAG generation support PNAG termination as the primary in vivo mechanism of biofilm inhibition by 6-fluoro UDP-GlcNAc.

scholarly journals Characterization of Shiga Toxin-Producing Escherichia coli Isolates Associated with Two Multistate Food-Borne Outbreaks That Occurred in 2006

2007 ◽  
Vol 74 (4) ◽  
pp. 1268-1272 ◽  
Author(s):  
G. A. Uhlich ◽  
J. R. Sinclair ◽  
N. G. Warren ◽  
W. A. Chmielecki ◽  
P. Fratamico
Keyword(s):  
Escherichia Coli ◽  
Stress Responses ◽  
Shiga Toxin ◽  
Gel Electrophoresis ◽  
Biofilm Formation ◽  
Pulsed Field Gel Electrophoresis ◽  
E Coli ◽  
Food Borne ◽  
Variant Genes

ABSTRACT Shiga toxin-producing Escherichia coli isolates from two 2006 outbreaks were compared to other O157:H7 isolates for virulence genotype, biofilm formation, and stress responses. Spinach- and lettuce-related-outbreak strains had similar pulsed-field gel electrophoresis patterns, and all carried both stx 2 and stx 2c variant genes. Cooperative biofilm formation involving an E. coli O157:H7 strain and a non-O157:H7 strain was also demonstrated.

Rapid, Refined, and Robust Method for Expression, Purification, and Characterization of Recombinant Human Amyloid-beta M1-42

2019 ◽  
Author(s):  
Priya Prakash ◽  
Travis Lantz ◽  
Krupal P. Jethava ◽  
Gaurav Chopra
Keyword(s):  
Amyloid Beta ◽  
Western Blots ◽  
Force Microscopy ◽  
E Coli ◽  
Atomic Force ◽  
Set Up ◽  
Short Time

Amyloid plaques found in the brains of Alzheimer’s disease (AD) patients primarily consists of amyloid beta 1-42 (Ab42). Commercially, Ab42 is synthetized using peptide synthesizers. We describe a robust methodology for expression of recombinant human Ab(M1-42) in Rosetta(DE3)pLysS and BL21(DE3)pLysS competent E. coli with refined and rapid analytical purification techniques. The peptide is isolated and purified from the transformed cells using an optimized set-up for reverse-phase HPLC protocol, using commonly available C18 columns, yielding high amounts of peptide (~15-20 mg per 1 L culture) in a short time. The recombinant Ab(M1-42) forms characteristic aggregates similar to synthetic Ab42 aggregates as verified by western blots and atomic force microscopy to warrant future biological use. Our rapid, refined, and robust technique to purify human Ab(M1-42) can be used to synthesize chemical probes for several downstream in vitro and in vivo assays to facilitate AD research.

Antimicrobial Resistance and Virulence Characterization of E. Coli Isolated from Subclinical Mastitic Sheep and Goats

2018 ◽  
Vol 34 (3) ◽  
pp. 267-278
Author(s):  
Ashraf A. Abd El-Tawab ◽  
Mohamed G. Aggour ◽  
Fatma I. El- Hofy ◽  
Marwa M. Y. El- Mesalami
Keyword(s):  
Antimicrobial Resistance ◽  
Sheep And Goats ◽  
E Coli

scholarly journals Functional identification of ygiP as a positive regulator of the ttdA-ttdB-ygjE operon

Microbiology ◽  
2006 ◽  
Vol 152 (7) ◽  
pp. 2129-2135 ◽  
Author(s):  
Taku Oshima ◽  
Francis Biville
Keyword(s):  
Functional Characterization ◽  
Anaerobic Growth ◽  
Functional Identification ◽  
New Members ◽  
E Coli ◽  
Inner Membrane Protein ◽  
Tartrate Dehydratase

Functional characterization of unknown genes is currently a major task in biology. The search for gene function involves a combination of various in silico, in vitro and in vivo approaches. Available knowledge from the study of more than 21 LysR-type regulators in Escherichia coli has facilitated the classification of new members of the family. From sequence similarities and its location on the E. coli chromosome, it is suggested that ygiP encodes a lysR regulator controlling the expression of a neighbouring operon; this operon encodes the two subunits of tartrate dehydratase (TtdA, TtdB) and YgiE, an integral inner-membrane protein possibly involved in tartrate uptake. Expression of tartrate dehydratase, which converts tartrate to oxaloacetate, is required for anaerobic growth on glycerol as carbon source in the presence of tartrate. Here, it has been demonstrated that disruption of ygiP, ttdA or ygjE abolishes tartrate-dependent anaerobic growth on glycerol. It has also been shown that tartrate-dependent induction of the ttdA-ttdB-ygjE operon requires a functional YgiP.

scholarly journals Biofilm Formation in Xanthomonas arboricola pv. pruni: Structure and Development

Agronomy ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 546
Author(s):  
Pilar Sabuquillo ◽  
Jaime Cubero
Keyword(s):  
Biofilm Formation ◽  
Extracellular Polymeric Substances ◽  
Environmental Changes ◽  
Nutrient Content ◽  
Infection Process ◽  
Bacterial Attachment ◽  
Key Factors ◽  
Cell Structures ◽  
Microscopy Techniques

Xanthomonasarboricola pv. pruni (Xap) causes bacterial spot of stone fruit and almond, an important plant disease with a high economic impact. Biofilm formation is one of the mechanisms that microbial communities use to adapt to environmental changes and to survive and colonize plants. Herein, biofilm formation by Xap was analyzed on abiotic and biotic surfaces using different microscopy techniques which allowed characterization of the different biofilm stages compared to the planktonic condition. All Xap strains assayed were able to form real biofilms creating organized structures comprised by viable cells. Xap in biofilms differentiated from free-living bacteria forming complex matrix-encased multicellular structures which become surrounded by a network of extracellular polymeric substances (EPS). Moreover, nutrient content of the environment and bacterial growth have been shown as key factors for biofilm formation and its development. Besides, this is the first work where different cell structures involved in bacterial attachment and aggregation have been identified during Xap biofilm progression. Our findings provide insights regarding different aspects of the biofilm formation of Xap which improve our understanding of the bacterial infection process occurred in Prunus spp and that may help in future disease control approaches.

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