scholarly journals Temperature-Dependent Influence of FliA Overexpression on PHL628 E. coli Biofilm Growth and Composition

2021 ◽  
Vol 11 ◽  
Author(s):  
Luke D. Buck ◽  
Maddison M. Paladino ◽  
Kyogo Nagashima ◽  
Emma R. Brezel ◽  
Joshua S. Holtzman ◽  
...  
Keyword(s):  
Signaling Pathways ◽  
Laser Scanning ◽  
Protein Composition ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Structural Protein ◽  
Biofilm Growth ◽  
E Coli ◽  
Biofilm Production ◽  
The Impact

Biofilm growth and survival pose a problem in both medical and industrial fields. Bacteria in biofilms are more tolerant to antibiotic treatment due to the inability of antibiotics to permeate to the bottom layers of cells in a biofilm and the creation of altered microenvironments of bacteria deep within the biofilm. Despite the abundance of information we have about E. coli biofilm growth and maturation, we are still learning how manipulating different signaling pathways influences the formation and fitness of biofilm. Understanding the impact of signaling pathways on biofilm formation may narrow the search for novel small molecule inhibitors or activators that affect biofilm production and stability. Here, we study the influence of the minor sigma transcription factor FliA (RpoF, sigma-28), which controls late-stage flagellar assembly and chemotaxis, on biofilm production and composition at various temperatures in the E. coli strain PHL628, which abundantly produces the extracellular structural protein curli. We examined FliA’s influence on external cellular structures like curli and flagella and the biomolecular composition of the biofilm’s extracellular polymeric substance (EPS) using biochemical assays, immunoblotting, and confocal laser scanning microscopy (CLSM). At 37°C, FliA overexpression results in the dramatic growth of biofilm in polystyrene plates and more modest yet significant biofilm growth on silica slides. We observed no significant differences in curli concentration and carbohydrate concentration in the EPS with FliA overexpression. Still, we did see significant changes in the abundance of EPS protein using CLSM at higher growth temperatures. We also noticed increased flagellin concentration, a major structural protein in flagella, occurred with FliA overexpression, specifically in planktonic cultures. These experiments have aided in narrowing our focus to FliA’s role in changing the protein composition of the EPS, which we will examine in future endeavors.

scholarly journals Genotypically Different Clones ofStaphylococcus aureusAre Diverse in the Antimicrobial Susceptibility Patterns and Biofilm Formations

2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
Salman Sahab Atshan ◽  
Mariana Nor Shamsudin ◽  
Leslie Than Thian Lung ◽  
Zamberi Sekawi ◽  
Chong Pei Pei ◽  
...  
Keyword(s):  
Laser Scanning ◽  
Antimicrobial Activities ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Biofilm Production ◽  
High Concentrations ◽  
Human Infections ◽  
The Impact ◽  
Susceptibility Patterns

This study evaluated whether genotypically different clinical isolates ofS. aureushave similar susceptibilities to individual antibiotics. It further aims to check the impact of biofilm on thein vitroactivity of vancomycin, daptomycin, linezolid, and tigecycline againstS. aureusclones. The study used a total of 60 different clinical MSSA and MRSA isolates. Susceptibilities were performed in planktonic cultures by macrobroth dilution and epsilon-test (E test) system. Biofilm production was determined using an adherent plate assay. The efficacy of antimicrobial activities against biofilms formation was checked using confocal laser scanning microscopy (CLSM). The study found that similar and differentspa, MLST, and SCCmectypes displayed high variation in their susceptibilities to antibiotics with tigecycline and daptomycin being the most effective. The biofilms were found resistant to high concentrations of most antibiotics tested with daptomycin being the most effective drug used in adhesive biofilms. A considerable difference exists among similar and various clone types against antibiotics tested. This variation could have contributed to the degree of virulence even within the same clonal genotype and enhanced heterogeneity in the infection potential. Thus, the development of a rapid and precise identification profile for each clone in human infections is important.

Berberine Chloride Dihydrate Enthused Nanovesicles for the Management of Dermatitis

2020 ◽  
Vol 10 ◽  
Author(s):  
Nimisha Srivastava ◽  
Zeeshan Fatima ◽  
Chanchal Deep Kaur ◽  
Dilshad Ali Rizvi
Keyword(s):  
Laser Scanning ◽  
Skin Irritation ◽  
Research Work ◽  
Slight Modification ◽  
Entrapment Efficiency ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Chloride Dihydrate ◽  
E Coli ◽  
Berberine Chloride

Background: Dermatitis is a common inflammatory skin disease that is affecting up to 25% of children and 1%-3% of adults worldwide. Paucity of exact cure for dermatitis and untoward side effects of topical immunosuppressive steroids has resulted into a great need for making use of complementary medicine to treat dermatitis. Objective: The present research work involved the development of Berberine chloride dihydrate (BCD) enthused nanovesicles i.e. ethosomes for the management of dermatitis. Method: Ethosomes were prepared by slight modification of cold method using varying concentrations of SPC (1-3%) and ethanol (10-40%) Optimized batch BCD 12 was further added to Carbopol 934P for gel formation. GEL BCD 12 was subjected to “anti-bacterial, dermatitis and skin irritation study. Result: The vesicles were in size range 142.42-398.31 nm while polydispersity index (PDI) ranges from 0.114-1.56 and for zeta potential it was from-18.8 to -39.4. Entrapment efficiency was from 46.05-88.79 %. Confocal laser scanning microscopy showed penetration depth of rhodamine enthused ethosome across rat skin upto 110 µm which was significantly higher than rhodamine solution (10 µm). In the anti-bacterial study, BCD loaded ethosomal gel (EG) showed maximum zone of inhibition of 18.5 mm against E. coli, 14.5 mm against P. aeruginosa and 23.0 mm against S. aureus. In dinitrochlorobenzene (DNCB) induced mice dermatitis model histopathology study showed marked decrease in amount of inflammatory cell nucleus in mice treated with BCD loaded ethosomal gel followed by 56% and 50 % increase in ear swelling and ear mass respectively in morphology study. Conventional marketed formulation showed nominal decrease in epidermal thickness, 66.67 % increase in ear thickness and 63.64 % increase in ear mass. Further Primary irritation index was less than 0.4 indicating negligible irritation in all the groups. Conclusion: It can be concluded that ethosomal gel is not only an efficient carrier for BCD but also proves its potential for the management of dermatitis.

Confocal and SEM imaging to demonstrate food pathogen- biofilm biocontrol by pyocyanin from Pseudomonas aeruginosa BTRY1

2016 ◽  
Vol 6 (01) ◽  
pp. 5218
Author(s):  
Laxmi Mohandas ◽  
Anju T. R. ◽  
Sarita G. Bhat*
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Biofilm Formation ◽  
Laser Scanning ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Antibiofilm Activity ◽  
Opportunistic Pathogens ◽  
Redox Active ◽  
Sem Imaging ◽  
The Impact

An assortment of redox-active phenazine compounds like pyocyanin with their characteristic blue-green colour are synthesized by Pseudomonas aeruginosa, Gram-negative opportunistic pathogens, which are also considered one of the most commercially valuable microorganisms. In this study, pyocyanin from Pseudomonas aeruginosa BTRY1 from food sample was assessed for its antibiofilm activity by micro titer plate assay against strong biofilm producers belonging to the genera Bacillus, Staphylococcus, Brevibacterium and Micrococcus. Pyocyanin inhibited biofilm activity in very minute concentrations. This was also confirmed by Scanning Electron Microscopy (SEM) and Confocal Laser Scanning Microscopy (CLSM). Both SEM and CLSM helped to visualize the biocontrol of biofilm formation by eight pathogens. The imaging and quantification by CLSM also established the impact of pyocyanin on biofilm-biocontrol mainly in the food industry.

scholarly journals The effect of the dispersion of microfibrillated cellulose on the mechanical properties of melt-compounded polypropylene–polyethylene copolymer

Cellulose ◽  
2019 ◽  
Vol 26 (18) ◽  
pp. 9645-9659 ◽  
Author(s):  
Caterina Palange ◽  
Marcus A. Johns ◽  
David J. Scurr ◽  
Jonathan S. Phipps ◽  
Stephen J. Eichhorn
Keyword(s):  
Tannic Acid ◽  
Laser Scanning ◽  
Secondary Ion Mass Spectrometry ◽  
High Surface ◽  
Microfibrillated Cellulose ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Cellulose Content ◽  
Reinforced Composites ◽  
The Impact

Abstract Microfibrillated cellulose (MFC) is a highly expanded, high surface area networked form of cellulose-based reinforcement. Due to the poor compatibility of cellulose with most common apolar thermoplastic matrices, the production of cellulose-reinforced composites in industry is currently limited to polar materials. In this study, a facile water-based chemistry, based on the reaction of MFC with tannic acid and subsequent functionalisation with an alkyl amine, is used to render the surface of the MFC fibrils hydrophobic and enhance the dispersion of the cellulose-based filler into an apolar thermoplastic matrix. The level of dispersion of the compatibilized MFC reinforced composites was evaluated using Time of Flight Secondary Ion Mass Spectrometry and multi-channel Spectral Confocal Laser Scanning Microscopy. The agglomeration of cellulosic filler within the composites was reduced by functionalising the surface of the MFC fibrils with tannic acid and octadecylamine. The resulting composites exhibited an increase in modulus at a high cellulose content. Despite the dispersion of a large portion of the functionalised filler, the presence of some remaining aggregates affected the impact properties of the composites produced.

scholarly journals Organo-Selenium-Containing Polyester Bandage Inhibits Bacterial Biofilm Growth on the Bandage and in the Wound

Biomedicines ◽  
2020 ◽  
Vol 8 (3) ◽  
pp. 62
Author(s):  
Phat Tran ◽  
Tyler Enos ◽  
Keaton Luth ◽  
Abdul Hamood ◽  
Coby Ray ◽  
...  
Keyword(s):  
Wound Infection ◽  
Wound Dressing ◽  
Laser Scanning ◽  
Bacterial Biofilm ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Bacterial Strains ◽  
Biofilm Growth ◽  
Biofilm Model

The dressing material of a wound plays a key role since bacteria can live in the bandage and keep re-infecting the wound, thus a bandage is needed that blocks biofilm in the bandage. Using an in vivo wound biofilm model, we examined the effectiveness of an organo-selenium (OS)-coated polyester dressing to inhibit the growth of bacteria in a wound. Staphylococcus aureus (as well as MRSA, Methicillin resistant Staph aureus), Stenotrophomonas maltophilia, Enterococcus faecalis, Staphylococcus epidermidis, and Pseudomonas aeruginosa were chosen for the wound infection study. All the bacteria were enumerated in the wound dressing and in the wound tissue under the dressing. Using colony-forming unit (CFU) assays, over 7 logs of inhibition (100%) was found for all the bacterial strains on the material of the OS-coated wound dressing and in the tissue under that dressing. Confocal laser scanning microscopy along with IVIS spectrum in vivo imaging confirmed the CFU results. Thus, the dressing acts as a reservoir for a biofilm, which causes wound infection. The same results were obtained after soaking the dressing in PBS at 37 °C for three months before use. These results suggest that an OS coating on polyester dressing is both effective and durable in blocking wound infection.

scholarly journals Mosaic-CLSM Assessment of Bacterial Spatial Distribution in Cosmetic Matrices According to Matrix Viscosity and Bacterial Hydrophobicity

Cosmetics ◽  
2020 ◽  
Vol 7 (2) ◽  
pp. 32
Author(s):  
Samia Almoughrabie ◽  
Chrisse Ngari ◽  
Romain Briandet ◽  
Valérie Poulet ◽  
Florence Dubois-Brissonnet
Keyword(s):  
Spatial Distribution ◽  
Laser Scanning ◽  
Rapid Assessment ◽  
Challenge Test ◽  
Surface Hydrophobicity ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Bacterial Surface ◽  
Bacterial Hydrophobicity ◽  
The Impact

The reliability of the challenge test depends, among other parameters, on the spatial distribution of microorganisms in the matrix. The present study aims to quickly identify factors that are susceptible to impair a uniform distribution of inoculated bacteria in cosmetic matrices in this context. We used mosaic confocal laser scanning microscopy (M-CLSM) to obtain rapid assessment of the impact of the composition and viscosity of cosmetic matrices on S. aureus spatial distribution. Several models of cosmetic matrices were formulated with different concentrations of two thickeners and were inoculated with three S. aureus strains having different levels of hydrophobicity. The spatial distribution of S. aureus in each matrix was evaluated according to the frequency distribution of the fluorescence values of at least 1350 CLSM images. We showed that, whatever the thickener used, an increasingly concentration of thickener results in increasingly bacterial clustered distribution. Moreover, higher bacterial hydrophobicity also resulted in a more clustered spatial distribution. In conclusion, CLSM-based method allows a rapid characterization of bacterial spatial distribution in complex emulsified systems. Both matrix viscosity and bacterial surface hydrophobicity affect the bacterial spatial distribution which can have an impact on the reliability of bacterial enumeration during challenge test.

scholarly journals The Chromosomal Toxin Gene yafQ Is a Determinant of Multidrug Tolerance for Escherichia coli Growing in a Biofilm

2009 ◽  
Vol 53 (6) ◽  
pp. 2253-2258 ◽  
Author(s):  
Joe J. Harrison ◽  
William D. Wade ◽  
Sarah Akierman ◽  
Caterina Vacchi-Suzzi ◽  
Carol A. Stremick ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Stationary Phase ◽  
Cell Survival ◽  
Laser Scanning ◽  
Laser Scanning Microscopy ◽  
Cell Counting ◽  
Confocal Laser ◽  
Toxin Gene ◽  
Persister Cells ◽  
E Coli

ABSTRACT Escherichia coli is refractory to elevated doses of antibiotics when it is growing in a biofilm, and this is potentially due to high numbers of multidrug-tolerant persister cells in the surface-adherent population. Previously, the chromosomal toxin-antitoxin loci hipBA and relBE have been linked to the frequency at which persister cells occur in E. coli populations. In the present study, we focused on the dinJ-yafQ-encoded toxin-antitoxin system and hypothesized that deletion of the toxin gene yafQ might influence cell survival in antibiotic-exposed biofilms. By using confocal laser scanning microscopy and viable cell counting, it was determined that a ΔyafQ mutant produced biofilms with a structure and a cell density equivalent to those of the parental strain. In-depth susceptibility testing identified that relative to wild-type E. coli, the ΔyafQ strain had up to a ∼2,400-fold decrease in cell survival after the biofilms were exposed to bactericidal concentrations of cefazolin or tobramycin. Corresponding to these data, controlled overexpression of yafQ from a high-copy-number plasmid resulted in up to a ∼10,000-fold increase in the number of biofilm cells surviving exposure to these bactericidal drugs. In contrast, neither the inactivation nor the overexpression of yafQ affected the tolerance of biofilms to doxycycline or rifampin (rifampicin). Furthermore, deletion of yafQ did not affect the tolerance of stationary-phase planktonic cells to any of the antibacterials tested. These results suggest that yafQ mediates the tolerance of E. coli biofilms to multiple but specific antibiotics; moreover, our data imply that this cellular pathway for persistence is likely different from that of multidrug-tolerant cells in stationary-phase planktonic cell cultures.

scholarly journals Effects of Current Velocity on the Nascent Architecture of Stream Microbial Biofilms

2003 ◽  
Vol 69 (9) ◽  
pp. 5443-5452 ◽  
Author(s):  
Tom J. Battin ◽  
Louis A. Kaplan ◽  
J. Denis Newbold ◽  
Xianhao Cheng ◽  
Claude Hansen
Keyword(s):  
Current Velocity ◽  
Laser Scanning ◽  
Extracellular Polymeric Substances ◽  
Amperometric Detection ◽  
Monosaccharide Composition ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Biofilm Growth ◽  
Temporal Shift ◽  
Glucose Levels

ABSTRACT Current velocity affected the architecture and dynamics of natural, multiphyla, and cross-trophic level biofilms from a forested piedmont stream. We monitored the development and activity of biofilms in streamside flumes operated under two flow regimes (slow [0.065 m s−1] and fast [0.23 m s−1]) by combined confocal laser scanning microscopy with cryosectioning to observe biofilm structure and composition. Biofilm growth started as bacterial microcolonies embedded in extracellular polymeric substances and transformed into ripple-like structures and ultimately conspicuous quasihexagonal networks. These structures were particularly pronounced in biofilms grown under slow current velocities and were characterized by the prominence of pennate diatoms oriented along their long axes to form the hexagons. Microstructural heterogeneity was dynamic, and biofilms that developed under slower velocities were thicker and had larger surface sinuosity and higher areal densities than their counterparts exposed to higher velocities. Surface sinuosity and biofilm fragmentation increased with thickness, and these changes likely reduced resistance to the mass transfer of solutes from the water column into the biofilms. Nevertheless, estimates of dissolved organic carbon uptake and microbial growth suggested that internal cycling of carbon was more important in thick biofilms grown in slow flow conditions. High-pressure liquid chromatography-pulsed amperometric detection analyses of exopolysaccharides documented a temporal shift in monosaccharide composition as the glucose levels decreased and the levels of rhamnose, galactose, mannose, xylose, and arabinose increased. We attribute this change in chemical composition to the accumulation of diatoms and increased incorporation of detrital particles in mature biofilms.

scholarly journals Electrochemical and surface analytical techniques applied to microbiologically influenced corrosion investigation

2018 ◽  
Vol 36 (4) ◽  
pp. 349-363 ◽  
Author(s):  
László Trif ◽  
Abdul Shaban ◽  
Judit Telegdi
Keyword(s):  
Photoelectron Spectroscopy ◽  
Laser Scanning ◽  
Electrochemical Impedance ◽  
Electrochemical Techniques ◽  
Analytical Techniques ◽  
Laser Scanning Microscopy ◽  
Microbiologically Influenced Corrosion ◽  
Microbial Consortia ◽  
Confocal Laser ◽  
The Impact

AbstractSuitable application of techniques for detection and monitoring of microbiologically influenced corrosion (MIC) is crucial for understanding the mechanisms of the interactions and for selecting inhibition and control approaches. This paper presents a review of the application of electrochemical and surface analytical techniques in studying the MIC process of metals and their alloys. Conventional electrochemical techniques, such as corrosion potential (Ecorr), redox potential, dual-cell technique, polarization curves, electrochemical impedance spectroscopy (EIS), electrochemical noise (EN) analysis, and microelectrode techniques, are discussed, with examples of their use in various MIC studies. Electrochemical quartz crystal microbalance, which is newly used in MIC study, is also discussed. Microscopic techniques [scanning electron microscopy (SEM), environmental SEM (ESEM), atomic force microscopy (AFM), confocal laser microscopy (CLM), confocal laser scanning microscopy (CLSM), confocal Raman microscopy] and spectroscopic analytical methods [Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS)] are also highlighted. This review highlights the heterogeneous characteristics of microbial consortia and use of special techniques to study their probable effects on the metal substrata. The aim of this review is to motivate using a combination of new procedures for research and practical measurement and calculation of the impact of MIC and biofilms on metals and their alloys.

scholarly journals Inhibition of Escherichia coli Biofilm Formation by Self-Assembled Monolayers of Functional Alkanethiols on Gold

2007 ◽  
Vol 73 (13) ◽  
pp. 4300-4307 ◽  
Author(s):  
Shuyu Hou ◽  
Erik A. Burton ◽  
Karen A. Simon ◽  
Dustin Blodgett ◽  
Yan-Yeung Luk ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Biofilm Formation ◽  
Laser Scanning ◽  
Laser Scanning Microscopy ◽  
Amide Bond ◽  
Self Assembled Monolayers ◽  
Confocal Laser ◽  
E Coli ◽  
Assembled Monolayers ◽  
Self Assembled

ABSTRACT Bacterial biofilms cause serious problems, such as antibiotic resistance and medical device-related infections. To further understand bacterium-surface interactions and to develop efficient control strategies, self-assembled monolayers (SAMs) of alkanethiols presenting different functional groups on gold films were analyzed to determine their resistance to biofilm formation. Escherichia coli was labeled with green florescence protein, and its biofilm formation on SAM-modified surfaces was monitored by confocal laser scanning microscopy. The three-dimensional structures of biofilms were analyzed with the COMSTAT software to obtain information about biofilm thickness and surface coverage. SAMs presenting methyl, l-gulonamide (a sugar alcohol tethered with an amide bond), and tri(ethylene glycol) (TEG) groups were tested. Among these, the TEG-terminated SAM was the most resistant to E. coli biofilm formation; e.g., it repressed biofilm formation by E. coli DH5α by 99.5% ± 0.1% for 1 day compared to the biofilm formation on a bare gold surface. When surfaces were patterned with regions consisting of methyl-terminated SAMs surrounded by TEG-terminated SAMs, E. coli formed biofilms only on methyl-terminated patterns. Addition of TEG as a free molecule to growth medium at concentrations of 0.1 and 1.0% also inhibited biofilm formation, while TEG at concentrations up to 1.5% did not have any noticeable effects on cell growth. The results of this study suggest that the reduction in biofilm formation on surfaces modified with TEG-terminated SAMs is a result of multiple factors, including the solvent structure at the interface, the chemorepellent nature of TEG, and the inhibitory effect of TEG on cell motility.

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