scholarly journals Gas Crosstalk between PFPE–PEG–PFPE Triblock Copolymer Surfactant-Based Microdroplets and Monitoring Bacterial Gas Metabolism with Droplet-Based Microfluidics

Biosensors ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 172
Author(s):  
Sunghyun Ki ◽  
Dong-Ku Kang
Keyword(s):  
Single Molecule ◽  
Color Change ◽  
Luria Bertani ◽  
Phenol Red ◽  
Bacterial Cells ◽  
Ammonia Gas ◽  
Luria Bertani Broth ◽  
Droplet Stability ◽  
Gas Metabolism ◽  
K 12

The PFPE–PEG–PFPE (Perfluoropolyether-polyethylene glycol-perfluoropolyether) surfactant has been used in droplet-based microfluidics and is known to provide high droplet stability and biocompatibility. Since this surfactant ensures the stability of droplets, droplet-based microfluidic systems have been widely used to encapsulate and analyze various biological components at the single-molecule scale, including viruses, bacteria, nucleic acids and proteins. In this study, we experimentally confirmed that gas crosstalk occurred between droplets formed by fluorinated oil and the PFPE–PEG–PFPE surfactant. E. coli K-12 bacterial cells were encapsulated with Luria–Bertani broth within droplets for the cultivation, and gas crosstalk was identified with neighboring droplets that contain phenol red. Since bacteria produce ammonia gas during its metabolism, penetration of ammonia gas initiates a color change of phenol red-containing droplets. Ammonia gas exchange was also confirmed by reacting ammonium chloride and sodium hydroxide within droplets that encapsulated. Herein, we demonstrate the gas crosstalk issue between droplets when it is formed using the PFPE–PEG–PFPE surfactant and also confirm that the density of droplet barrier has effects on gas crosstalk. Our results also suggest that droplet-based microfluidics can be used for the monitoring of living bacteria by the determination of bacterial metabolites during cultivation.

Comparative Analysis of Shigella boydii 18 Foodborne Outbreak Isolate and Related Enteric Bacteria: Role of rpoS and adiA in Acid Stress Response

2005 ◽  
Vol 68 (3) ◽  
pp. 521-527 ◽  
Author(s):  
YVONNE C. CHAN ◽  
HANS P. BLASCHEK
Keyword(s):  
Minimal Medium ◽  
Enteric Bacteria ◽  
Arginine Decarboxylase ◽  
Luria Bertani ◽  
Decarboxylase Activity ◽  
E Coli ◽  
Rpos Gene ◽  
Shigella Boydii ◽  
Luria Bertani Broth ◽  
K 12

Shigella boydii CDPH (Chicago Department of Public Health) serotype 18 was implicated in an outbreak of foodborne illness in 1998. The suspected food vehicles were parsley and cilantro imported from Mexico used to prepare bean salad. Previous studies revealed that S. boydii CDPH serotype 18 can survive in bean salad, which contains organic acids and whose pH decreases over time. Acid challenge assays in acidified tryptic soy broth at pH 4.5, acidified Luria-Bertani broth at pH 4.5, and acidified M9 minimal salts medium at pH 2.5 containing amino acids, arginine, or glutamic acid were performed using S. boydii CDPH, S. boydii ATCC 35966, S. flexneri 3136, Escherichia coli O157:H7 dd8872, and E. coli O157:H7 dd642 to compare differences in acid tolerance. Differences in survival of exponential-phase cells were detected in acidified tryptic soy broth and Luria-Bertani broth at pH 4.5. In acidified minimal medium containing arginine, S. boydii strains were able to survive at pH 2.5. The arginine decarboxylase gene (adiA) present in S. boydii is involved in survival at extremely low pH. The discovery of adiA expression in S. boydii serotype 18 by use of an acidified minimal medium challenge and arginine decarboxylase biochemical assay is significant because arginine decarboxylase activity was thought to be unique to E. coli. Sequencing of the rpoS gene from the S. boydii outbreak strain indicates that it is 99% conserved compared with the E. coli K-12 rpoS gene and plays a vital role in survival under acidic conditions.

scholarly journals Flagellin of Enteropathogenic Escherichia coli Stimulates Interleukin-8 Production in T84 Cells

2003 ◽  
Vol 71 (4) ◽  
pp. 2120-2129 ◽  
Author(s):  
Xin Zhou ◽  
Jorge A. Girón ◽  
Alfredo G. Torres ◽  
J. Adam Crawford ◽  
Erasmo Negrete ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Epithelial Cells ◽  
Luria Bertani ◽  
Interleukin 8 ◽  
Epec Strain ◽  
T84 Cells ◽  
E Coli ◽  
Luria Bertani Broth ◽  
Mitogen Activated Protein ◽  
K 12

ABSTRACT The type III secretion system (TTSS) of enteropathogenic Escherichia coli (EPEC) has been associated with the ability of these bacteria to induce secretion of proinflammatory cytokines, including interleukin-8 (IL-8), in cultured epithelial cells. However, the identity of the effector molecule directly involved in this event is unknown. In this study, we determined that the native flagellar filament and its flagellin monomer are activators of IL-8 release in T84 epithelial cells. Supernatants of wild-type EPEC strain E2348/69 and its isogenic mutants deficient in TTSS (escN) and in production of intimin (eae), grown in Luria-Bertani broth, elicited similar amounts of IL-8 secretion by T84 cells. In contrast, supernatants of EPEC fliC mutants and of B171, a nonflagellated EPEC strain, were defective in inducing IL-8 release, a phenotype that was largely restored by complementation of the fliC gene in the mutant lacking flagella. Purified flagella from E. coli K-12, EPEC serotypes H6 and H34, and enterohemorrhagic E. coli serotype H7 all induced IL-8 release in T84 cells. Induction of IL-8 by purified flagella or His-tagged FliC from EPEC strain E2348/69 was dose dependent and was blocked by a polyclonal anti-H6 antibody. Finally, the mitogen-activated protein kinases (Erk1 and -2 and Jnk) were phosphorylated in flagellin-treated T84 cells, and inhibition of the p38 and Erk pathways significantly decreased the IL-8 response induced by EPEC flagellin. Our data clearly indicate that FliC of EPEC is sufficient to induce IL-8 release in T84 cells and that activation of the Erk and p38 pathways is required for IL-8 induction.

scholarly journals Treadmilling FtsZ polymers drive the directional movement of sPG-synthesis enzymes via a Brownian ratchet mechanism

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Joshua W. McCausland ◽  
Xinxing Yang ◽  
Georgia R. Squyres ◽  
Zhixin Lyu ◽  
Kevin E. Bruce ◽  
...  
Keyword(s):  
Cell Wall ◽  
Single Molecule ◽  
Theoretical Modelling ◽  
Binding Potential ◽  
Central Component ◽  
Macromolecular Complex ◽  
Bacterial Cells ◽  
Brownian Ratchet ◽  
Ratchet Mechanism ◽  
Directional Movement

AbstractThe FtsZ protein is a central component of the bacterial cell division machinery. It polymerizes at mid-cell and recruits more than 30 proteins to assemble into a macromolecular complex to direct cell wall constriction. FtsZ polymers exhibit treadmilling dynamics, driving the processive movement of enzymes that synthesize septal peptidoglycan (sPG). Here, we combine theoretical modelling with single-molecule imaging of live bacterial cells to show that FtsZ’s treadmilling drives the directional movement of sPG enzymes via a Brownian ratchet mechanism. The processivity of the directional movement depends on the binding potential between FtsZ and the sPG enzyme, and on a balance between the enzyme’s diffusion and FtsZ’s treadmilling speed. We propose that this interplay may provide a mechanism to control the spatiotemporal distribution of active sPG enzymes, explaining the distinct roles of FtsZ treadmilling in modulating cell wall constriction rate observed in different bacteria.

scholarly journals Insight into the Metabolic Profiles of Pb(II) Removing Microorganisms

Molecules ◽  
2021 ◽  
Vol 26 (13) ◽  
pp. 4008
Author(s):  
Carla Cilliers ◽  
Evans M. N. Chirwa ◽  
Hendrik G. Brink
Keyword(s):  
Liquid Chromatography ◽  
High Performance ◽  
Microbial Consortium ◽  
Luria Bertani ◽  
Nutrient Concentrations ◽  
Batch Experiments ◽  
Metabolic Study ◽  
Luria Bertani Broth ◽  
Tandem Mass Spectroscopy ◽  
Insight Into

The objective of the study was to gather insight into the metabolism of lead-removing microorganisms, coupled with Pb(II) removal, biomass viability and nitrate concentrations for Pb(II) bioremoval using an industrially obtained microbial consortium. The consortium used for study has proven to be highly effective at removing aqueous Pb(II) from solution. Anaerobic batch experiments were conducted with Luria-Bertani broth as rich growth medium over a period of 33 h, comparing a lower concentration of Pb(II) with a higher concentration at two different nutrient concentrations. Metabolite profiling and quantification were conducted with the aid of both liquid chromatography coupled with tandem mass spectroscopy (UPLC-HDMS) in a “non-targeted” fashion and high-performance liquid chromatography (HPLC) in a “targeted” fashion. Four main compounds were identified, and a metabolic study was conducted on each to establish their possible significance for Pb(II) bioremoval. The study investigates the first metabolic profile to date for Pb(II) bioremoval, which in turn can result in a clarified understanding for development on an industrial and microbial level.

scholarly journals Evaluación in vitro de la microfiltración de Enterococcus faecalis usando cinco técnicas de obturación / In Vitro Evaluation of Enterococcus faecalis Microleakage Using Five Obturation Techniques

2016 ◽  
Vol 35 (74) ◽  
Author(s):  
Silvia Elena Aragón Matamoros ◽  
Tomás Alberto Guindos Moya ◽  
Yanina Meza González ◽  
Diana Morales Herrera ◽  
María Alejandra Perera Díaz ◽  
...  
Keyword(s):  
Enterococcus Faecalis ◽  
Color Change ◽  
Three Dimensional ◽  
Brain Heart Infusion ◽  
Phenol Red ◽  
Root Canal Filling ◽  
Gutta Percha ◽  
Single Cone ◽  
Primary Lateral

<p><strong>ABSTRACT. </strong><em><strong>Background:</strong></em> The root canal filling technique named Hybrid-Mixed Condensation, combines the advantages of cold lateral and warm vertical condensation. The ability of avoiding microbial microleakage has not been proven. <em><strong>Purpose:</strong></em> To evaluate the differences of microbial microleakage using <em>Enterococcus faecalis</em>, in canals obturated with five different techniques: lateral, warm vertical, WaveOne® single cone, Guttacore®, and Hybrid-mixed condensation. <em><strong>Methods:</strong></em> 50 single-rooted human premolars extracted for orthodontic reasons were biomechanical prepared with primary file of WaveOne® system. Teeth were divided into 5 groups using different obturation techniques: single cone with WaveOne® Primary, lateral condensation using 2 % gutta-percha cones, Guttacore® 30, warm vertical condensation using down packing in a WaveOne® Primary cone and backfill with alpha gutapercha of Beefill®, and the hybrid mixed condensation modifying the lateral condensation with heat and a backfill using Beefill®. <em>Enterococcus faecalis</em> was inoculated in the coronal third and apices were immersed in brain heart infusion broth with phenol red incubated at 37 °C for 12 weeks. Microfiltration was determined with color change and turbidity of the medium. Specimens were observed by scanning electron microscopy. <em><strong>Results:</strong></em> Only 11 teeth (22 %) were positive for leakage. 46 % with single cone, 30 % with Guttacore®, 20 % with lateral condensation, 10 % with warm vertical condensation and no microleakage was found for Hybrid-Mixed Technique over the period of 12 weeks of study. <em><strong>Conclusion:</strong></em> Hybrid Mixed Technique showed to be the most efficient technique to get three-dimensional seal and prevent microbial contamination of canals in the endodontic therapy.</p>

scholarly journals EVALUASI HEMATOTOKSIK SECARA IN VITRO NANOPARTIKEL ZnS HASIL REDUKSI BIOMATRIKS Eschericia coli

2020 ◽  
Vol 23 (3) ◽  
pp. 82-84
Author(s):  
Lisa Kurniati ◽  
Andi Arjuna ◽  
Sukamto S Mamada
Keyword(s):  
Escherichia Coli ◽  
Luria Bertani ◽  
Luria Bertani Broth

Nanopartikel ZnS merupakan material semi konduktor yang memiliki sifat unik dan manfaat yang besar dibidang kesehatan, terutama sebagai antibakteri dan biomarker kanker. Walaupun demikian, informasi mengenai toksisitas dari nanopartikel ZnS masih sangat terbatas. Oleh karena itu, pada penelitian ini telah dilakukan evaluasi hematotoksisitas secara in vitro nanopartikel ZnS hasil reduksi biomatriks Escherichia coli. Penyiapan nanopartikel ZnS diawali dengan pencampuran dispersi ZnSO4 konsentrasi 200 bpj ke dalam medium Luria Bertani Broth (LBB) yang ditumbuhi E.Coli  sebagai bioreduktor. Produk yang dihasilkan dikarakterisasi dengan uji photolimunisence (PL) dan spektrofotometri pada rentang panjang gelombang 250-700 nm. Hasilnya, nanopartikel ZnS berpendar biru dan diidentifikasi pada λmax 288 nm dengan absorbansi 0,905. Partikel yang dihasilkan kemudian didispersikan dengan variasi volume 30 µl, 40 µl, 50 µl pada larutan tyrod. Data persentase hemolisis secara berturut-turut adalah 32%, 39%, 22%, 0% (kontrol negatif) dan 100% (kontrol positif). Sehingga dapat disimpulkan bahwa nanopartikel ZnS hasil reduksi E.coli memberikan efek toksik terhadap sel darah merah

scholarly journals Antimicrobial and Antibiofilm Properties of Graphene Oxide on Enterococcus faecalis

Antibiotics ◽  
2020 ◽  
Vol 9 (10) ◽  
pp. 692
Author(s):  
Cecilia Martini ◽  
Francesca Longo ◽  
Raffaella Castagnola ◽  
Luca Marigo ◽  
Nicola Maria Grande ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Enterococcus Faecalis ◽  
Antibacterial Properties ◽  
Luria Bertani ◽  
Bacterial Suspension ◽  
Adhesion Properties ◽  
High Antibacterial Activity ◽  
Luria Bertani Broth ◽  
Bacterial Film

The aim of this study was to evaluate the antibacterial properties of graphene oxide (GO) against Enterococcus faecalis in vitro conditions and when used to coat dentin surface to prevent E. faecalis adhesion. The ATCC strain of E. faecalis 29212 has been used to perform a viability test. The pellet was suspended in ultrapure water, NaCl, PBS buffer, CaCl2 and MgCl2, Luria−Bertani broth solutions. The viability was evaluated by the colony forming unit counting method. Atomic force microscopy images and the measure of surface zeta potential variation were analyzed. Dentin discs were covered with a film of GO (n = 15) or were not treated (n = 15). Bacterial suspension was added to each sample of dentine discs and microbial counts were calculated. Statistically significant differences between two groups were assessed by a two-tailed unpaired t-test. Bacteria cell morphology was investigated with scanning electron microscopy. The highest growth inhibition was obtained in ddH2O and CaCl2 solution while, in PBS and NaCl, GO had poor antibacterial efficacy with a growth enhancing effect in the latter. GO on dentin discs demonstrated high antibacterial activity. GO film has demonstrated acceptable adhesion properties to root dentin and a role in the inhibition of bacterial film proliferation and biofilm formation.

scholarly journals The Real-Time-Based Assessment of the Microbial Killing by the Antimicrobial Compounds of Neutrophils

2011 ◽  
Vol 11 ◽  
pp. 2382-2390 ◽  
Author(s):  
J. T. Atosuo ◽  
E.-M. Lilius
Keyword(s):  
Real Time ◽  
Antimicrobial Agents ◽  
Hypochlorous Acid ◽  
Bacterial Cells ◽  
Photorhabdus Luminescens ◽  
Bacterial Luciferase ◽  
E Coli ◽  
High Concentrations ◽  
Time Basis ◽  
K 12

A recombinantEscherichia coliK-12 strain, transformed with a modified bacterial luciferase gene (luxABCDE) fromPhotorhabdus luminescens, was constructed in order to monitor the activity of various antimicrobial agents on a real-time basis. ThisE. coli-lux emitted, without any addition of substrate, constitutive bioluminescence (BL), which correlated to the number of viable bacterial cells. The decrease in BL signal correlated to the number of killed bacterial cells. Antimicrobial activity of hydrogen peroxide (H2O2) and myeloperoxidase (MPO) was assessed. In high concentrations, H2O2alone had a bacteriocidic function and MPO enhanced this killing by forming hypochlorous acid (HOCl). Taurine, the known HOCl scavenger, blocked the killing by MPO. WhenE. coli-lux was incubated with neutrophils, similar killing kinetics was recorded as in H2O2/MPO experiments. The opsonization of bacteria enhanced the killing, and the maximum rate of the MPO release from lysosomes coincided with the onset of the killing.

scholarly journals 3D Single-Molecule Tracking of Confined Diffusers: Resolving Intracellular Diffusive States in Living Bacterial Cells

2018 ◽  
Vol 114 (3) ◽  
pp. 537a
Author(s):  
Ting Yan ◽  
Julian Rocha ◽  
Alecia Marie Achimovich ◽  
Andreas Gahlmann
Keyword(s):  
Single Molecule ◽  
Bacterial Cells ◽  
Single Molecule Tracking
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