scholarly journals Biocoatings: Painting bacteria on surfaces

2020 ◽  
Vol 2 (7A) ◽  
Author(s):  
Simone Krings ◽  
Yuxiu Chen ◽  
Suzie Hingley-Wilson ◽  
Joseph L. Keddie
Keyword(s):  
Laser Scanning ◽  
Fluorescent Protein ◽  
Yellow Fluorescent Protein ◽  
Inorganic Nanoparticles ◽  
Laser Scanning Microscopy ◽  
Polymer Materials ◽  
Latex Film ◽  
Confocal Laser ◽  
Bacterial Cells ◽  
E Coli

Background: Biocoatings are nanoporous polymer materials which encapsulate bacterial cells with carbohydrates as osmoprotectants. Here, we optimised biocoatings to offer a favourable environment for the metabolic activity of bacteria. Methods: E. coli were used as a model organism and mixed with the colloidal polymer particles (i.e. synthetic latex), inorganic nanoparticles and different carbohydrates. Films were casted and dried to create a coalesced latex film and finally rehydrated to re-establish bacterial metabolism. The toxicity of the sterile latices to the bacteria was tested by using the colourimetric redox indicator resazurin. Visualisation of the bacteria inside the biocoatings was performed by confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM). Results: We introduced halloysite (clay nanotubes) to create nanoporosity, which created voids in the structure that will permit gas exchange. The biocoatings were tested in liquid and rehydrated states with resazurin to find the most promising composition ensuring bacterial viability. Rehydrated biocoatings were visualised by CLSM by tracking the constitutively expressed yellow-fluorescent protein (YFP) for viable cells and the membrane exclusion dye propidium iodide for dead cells. The structure of the biocoatings appeared to be unaffected by freeze-drying compared to chemical fixation. Following this fixation, SEM allowed the observation of the organisation of the latex polymers, halloysite and bacteria. Conclusions: The biocoatings were highly porous thanks to halloysite. E. coli survived the film formation process. Next, we will use E. coli and cyanobacteria to achieve higher efficiency for a variety of applications e.g. pollutant degradation, solar energy harvesting and carbon recycling.

scholarly journals Aqueous mechano-bactericidal action of acicular aragonite crystals

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Nobuaki Negishi ◽  
Tomohiro Inaba ◽  
Yukari Miyazaki ◽  
Genki Ishii ◽  
Yingnan Yang ◽  
...  
Keyword(s):  
Laser Scanning ◽  
Hard Water ◽  
Petri Dish ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Black Silicon ◽  
Bacterial Cells ◽  
Bactericidal Action ◽  
E Coli ◽  
Biological Affinity

AbstractNanoneedle structures on dragonfly and cicada wing surfaces or black silicon nanoneedles demonstrate antibacterial phenomena, namely mechano-bactericidal action. These air-exposed, mechano-bactericidal surfaces serve to destroy adherent bacteria, but their bactericidal action in the water is no precedent to report. Calcium carbonate easily accumulates on solid surfaces during long-term exposure to hard water. We expect that aragonite nanoneedles, in particular, which grow on TiO2 during the photocatalytic treatment of calcium-rich groundwater, exhibit mechano-bactericidal action against bacteria in water. Here, we showed that acicular aragonite modified on TiO2 ceramics prepared from calcium bicarbonate in mineral water by photocatalysis exhibits mechanical bactericidal activity against E. coli in water. Unmodified, calcite-modified and aragonite-modified TiO2 ceramics were exposed to water containing E. coli (in a petri dish), and their bactericidal action over time was investigated under static and agitated conditions. The surfaces of the materials were observed by scanning electron microscopy, and the live/dead bacterial cells were observed by confocal laser scanning microscopy. As a result, the synergistic bactericidal performance achieved by mechano-bactericidal action and photocatalysis was demonstrated. Aragonite itself has a high biological affinity for the human body different from the other whisker-sharpen nanomaterials, therefore, the mechano-bactericidal action of acicular aragonite in water is expected to inform the development of safe water purification systems for use in developing countries.

scholarly journals Specific Electromagnetic Effects of Microwave Radiation on Escherichia coli

2011 ◽  
Vol 77 (9) ◽  
pp. 3017-3022 ◽  
Author(s):  
Yury Shamis ◽  
Alex Taube ◽  
Natasa Mitik-Dineva ◽  
Rodney Croft ◽  
Russell J. Crawford ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Cell Membrane ◽  
Cell Morphology ◽  
Laser Scanning ◽  
Simulation Software ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Bacterial Cells ◽  
Content Type ◽  
E Coli

ABSTRACTThe present study investigated the effects of microwave (MW) radiation applied under a sublethal temperature onEscherichia coli. The experiments were conducted at a frequency of 18 GHz and at a temperature below 40°C to avoid the thermal degradation of bacterial cells during exposure. The absorbed power was calculated to be 1,500 kW/m3, and the electric field was determined to be 300 V/m. Both values were theoretically confirmed using CST Microwave Studio 3D Electromagnetic Simulation Software. As a negative control,E. colicells were also thermally heated to temperatures up to 40°C using Peltier plate heating. Scanning electron microscopy (SEM) analysis performed immediately after MW exposure revealed that theE. colicells exhibited a cell morphology significantly different from that of the negative controls. This MW effect, however, appeared to be temporary, as following a further 10-min elapsed period, the cell morphology appeared to revert to a state that was identical to that of the untreated controls. Confocal laser scanning microscopy (CLSM) revealed that fluorescein isothiocyanate (FITC)-conjugated dextran (150 kDa) was taken up by the MW-treated cells, suggesting that pores had formed within the cell membrane. Cell viability experiments revealed that the MW treatment was not bactericidal, since 88% of the cells were recovered after radiation. It is proposed that one of the effects of exposingE. colicells to MW radiation under sublethal temperature conditions is that the cell surface undergoes a modification that is electrokinetic in nature, resulting in a reversible MW-induced poration of the cell membrane.

scholarly journals Aqueous Mechano-Bactericidal Action of Acicular Aragonite Crystals

2021 ◽  
Author(s):  
Nobuaki Negishi ◽  
Tomohiro Inaba ◽  
Yukari Miyazaki ◽  
Genki Ishii ◽  
Yang Yingnan ◽  
...  
Keyword(s):  
Laser Scanning ◽  
Hard Water ◽  
Petri Dish ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Black Silicon ◽  
Bacterial Cells ◽  
Bactericidal Action ◽  
E Coli ◽  
K 12

Abstract Nanoneedle structures on dragonfly and cicada wing surfaces or black silicon nanoneedles demonstrate antibacterial phenomena, namely mechano-bactericidal action. These air-exposed, mechano-bactericidal surfaces serve to destroy adherent bacteria, but their bactericidal action in the water is no precedent to report. Calcium carbonate easily accumulates on surfaces during long-term exposure to hard water. We expect that aragonite nanoneedles, in particular, which grow on TiO2 during the photocatalytic treatment of calcium-rich groundwater, exhibit mechano-bactericidal action against bacteria in water. Here, we show that aragonite nanoneedles are grown on TiO2 ceramics from the calcium bicarbonate in mineral water exhibit mechano-bactericidal action against E. coli K-12 in water. Unmodified, calcite-modified as references and aragonite-modified TiO2 ceramics were exposed to water containing E. coli K-12 (in a petri dish), and their bactericidal action over time was investigated under static and agitated conditions. The surfaces of the materials were observed by scanning electron microscopy, and the live/dead bacterial cells were observed by confocal laser scanning microscopy. Further, the synergistic bactericidal performance achieved by mechano-bactericidal action and photocatalysis was demonstrated. Aragonite itself has a high biological affinity for the human body different from the other whisker-sharpen nano-materials, therefore, the mechano-bactericidal action of acicular aragonite in water is expected to inform the development of safe water purification systems for use in developing countries.

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.

scholarly journals Potential role of nuclear translocation of glyceraldehyde-3-phosphate dehydrogenase in apoptosis and oxidative stress

2001 ◽  
Vol 114 (9) ◽  
pp. 1643-1653 ◽  
Author(s):  
Z. Dastoor ◽  
J.L. Dreyer
Keyword(s):  
Oxidative Stress ◽  
Laser Scanning ◽  
Fluorescent Protein ◽  
Nuclear Translocation ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Apoptotic Cells ◽  
Transfected Cells ◽  
And Oxidative Stress

Recent studies indicating a role of glyceraldehyde-3-phosphate dehydrogenase (GAPDH) in apoptosis or oxidative stress has been reported. Using confocal laser-scanning microscopy, we have investigated the cellular distribution of GAPDH in central nervous system (CNS)-derived cells (neuroblastoma mNB41A3), in non-CNS derived cells (R6 fibroblast) and in an apoptosis-resistant Bcl2 overexpressing cell line (R6-Bcl2). Induction of apoptosis by staurosporine or MG132 and oxidative stress by H(2)O(2) or FeCN enhanced the nuclear translocation of endogenous GAPDH in all cell types, as detected by immunocytochemistry. In apoptotic cells, GAPDH expression is three times higher than in non-apoptotic cells. Consistent with a role for GAPDH in apoptosis, overexpression of a GAPDH-green fluorescent protein (GAPDH-GFP) hybrid increased nuclear import of GAPDH-GFP into transfected cells and the number of apoptotic cells, and made them more sensitive to agents that induce apoptosis. Bcl2 overexpression prevents nuclear translocation of GAPDH and apoptosis in untransfected cells, but not in transfected cells that overexpress GAPDH-GFP. Our observations indicate that nuclear translocation of GAPDH may play a role in apoptosis and oxidative stress, probably related to the activity of GAPDH as a DNA repair enzyme or as a nuclear carrier for pro-apoptotic molecules.

Postharvest Handling Conditions Affect Internalization of Salmonella in Baby Spinach during Washing

2013 ◽  
Vol 76 (7) ◽  
pp. 1145-1151 ◽  
Author(s):  
VICENTE M. GÓMEZ-LÓPEZ ◽  
ALICIA MARÍN ◽  
ANA ALLENDE ◽  
LARRY R. BEUCHAT ◽  
MARÍA I. GIL
Keyword(s):  
Green Fluorescent Protein ◽  
Laser Scanning ◽  
Fluorescent Protein ◽  
Negative Temperature ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Temperature Differential ◽  
Postharvest Handling ◽  
Green Fluorescent ◽  
Spinach Leaves

Internalization of foodborne pathogens in fruits and vegetables is an increasing safety concern. The aim of this research was to assess the potential for internalization of an enteric pathogen (Salmonella enterica serotype Typhimurium) in a leafy vegetable (baby spinach) during washing as influenced by three postharvest handling conditions: (i) illumination, (ii) negative temperature differential, and (iii) relative humidity (RH). To compare these potential postharvest handling conditions, leaves were exposed to different levels of illumination (0, 1,000, and 2,000 lx), temperature differential (5, 11, 14, 20, and 26uC), and RH (99, 85, and 74%) for a short time before or during washing. Washing of baby spinach was carried out in water containing green fluorescent protein–tagged Salmonella Typhimurium (6.5 log CFU/ml) at 5uC for 2 min, followed by surface disinfection with chlorine (10,000 μg/ml) for 1 min, two rinses in water for 10 s, and spin drying for 15 s. Internalization was assessed by enumerating the pathogen on Salmonella-Shigella agar and by confocal laser scanning microscopy. Illumination of spinach leaves before and during washing and a negative temperature differential during washing did not significantly (P > 0.05) increase the number of internalized bacteria. However, exposure of leaves to low-RH conditions before washing, which reduced the tissue water content, decreased internalization of Salmonella compared with internalization in baby spinach exposed to high RH (P ≤ 0.05). Green fluorescent protein–tagged Salmonella Typhimurium was visualized by confocal laser scanning microscopy at a depth of up to 30 μm beneath the surface of spinach leaves after exposure to a high inoculum level (8 log CFU/ml) for an extended time (2 h). Results show that internalization of Salmonella into baby spinach leaves can occur but can be minimized under specific postharvest handling conditions such as low RH.

scholarly journals Calcite Biomineralization by Bacterial Isolates from the Recently Discovered Pristine Karstic Herrenberg Cave

2011 ◽  
Vol 78 (4) ◽  
pp. 1157-1167 ◽  
Author(s):  
Anna Rusznyák ◽  
Denise M. Akob ◽  
Sándor Nietzsche ◽  
Karin Eusterhues ◽  
Kai Uwe Totsche ◽  
...  
Keyword(s):  
Laser Scanning ◽  
Extracellular Polymeric Substances ◽  
Large Fraction ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Rrna Gene ◽  
Seepage Water ◽  
Bacterial Cells ◽  
Content Type ◽  
Rich Media

ABSTRACTKarstic caves represent one of the most important subterranean carbon storages on Earth and provide windows into the subsurface. The recent discovery of the Herrenberg Cave, Germany, gave us the opportunity to investigate the diversity and potential role of bacteria in carbonate mineral formation. Calcite was the only mineral observed by Raman spectroscopy to precipitate as stalactites from seepage water. Bacterial cells were found on the surface and interior of stalactites by confocal laser scanning microscopy. Proteobacteria dominated the microbial communities inhabiting stalactites, representing more than 70% of total 16S rRNA gene clones. Proteobacteria formed 22 to 34% of the detected communities in fluvial sediments, and a large fraction of these bacteria were also metabolically active. A total of 9 isolates, belonging to the generaArthrobacter,Flavobacterium,Pseudomonas,Rhodococcus,Serratia, andStenotrophomonas, grew on alkaline carbonate-precipitating medium. Two cultures with the most intense precipitate formation,Arthrobacter sulfonivoransandRhodococcus globerulus, grew as aggregates, produced extracellular polymeric substances (EPS), and formed mixtures of calcite, vaterite, and monohydrocalcite.R. globerulusformed idiomorphous crystals with rhombohedral morphology, whereasA. sulfonivoransformed xenomorphous globular crystals, evidence for taxon-specific crystal morphologies. The results of this study highlighted the importance of combining various techniques in order to understand the geomicrobiology of karstic caves, but further studies are needed to determine whether the mineralogical biosignatures found in nutrient-rich media can also be found in oligotrophic caves.

scholarly journals Visualization of the Peroxisomal Compartment in Living Mammalian Cells: Dynamic Behavior and Association with Microtubules

1997 ◽  
Vol 136 (1) ◽  
pp. 71-80 ◽  
Author(s):  
Erik A.C. Wiemer ◽  
Thibaut Wenzel ◽  
Thomas J. Deerinck ◽  
Mark H. Ellisman ◽  
Suresh Subramani
Keyword(s):  
Mammalian Cells ◽  
Laser Scanning ◽  
Fluorescent Protein ◽  
Time Lapse ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Small Subset ◽  
Subcellular Compartment ◽  
Directional Movement ◽  
Green Fluorescent

Peroxisomes in living CV1 cells were visualized by targeting the green fluorescent protein (GFP) to this subcellular compartment through the addition of a COOH-terminal peroxisomal targeting signal 1 (GFP–PTS1). The organelle dynamics were examined and analyzed using time-lapse confocal laser scanning microscopy. Two types of movement could be distinguished: a relatively slow, random, vibration-like movement displayed by the majority (∼95%) of the peroxisomes, and a saltatory, fast directional movement displayed by a small subset (∼5%) of the peroxisomes. In the latter instance, peak velocities up to 0.75 μm/s and sustained directional velocities up to 0.45 μm/s over 11.5 μm were recorded. Only the directional type of motion appeared to be energy dependent, whereas the vibrational movement continued even after the cells were depleted of energy. Treatment of cells, transiently expressing GFP–PTS1, with microtubule-destabilizing agents such as nocodazole, vinblastine, and demecolcine clearly altered peroxisome morphology and subcellular distribution and blocked the directional movement. In contrast, the microtubule-stabilizing compound paclitaxel, or the microfilament-destabilizing drugs cytochalasin B or D, did not exert these effects. High resolution confocal analysis of cells expressing GFP–PTS1 and stained with anti-tubulin antibodies revealed that many peroxisomes were associated with microtubules. The GFP–PTS1–labeled peroxisomes were found to distribute themselves in a stochastic, rather than ordered, manner to daughter cells at the time of mitosis.

Migration of Salmonella Enteritidis Phage Type 30 through Almond Hulls and Shells

2008 ◽  
Vol 71 (2) ◽  
pp. 397-401 ◽  
Author(s):  
MICHELLE D. DANYLUK ◽  
MARIA T. BRANDL ◽  
LINDA J. HARRIS
Keyword(s):  
Green Fluorescent Protein ◽  
Laser Scanning ◽  
Salmonella Enteritidis ◽  
Fluorescent Protein ◽  
Phage Type ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Aqueous Environment ◽  
Serovar Typhimurium ◽  
Green Fluorescent

The ability of Salmonella to migrate from an external aqueous environment through the almond hull and shell, and to colonize the kernel, was evaluated in two ways. First, the outer surface of shell halves from five varieties of almonds that differed in shell hardness were placed in contact with a suspension of Salmonella enterica serovar Enteritidis phage type 30 for 24hat24°C. Salmonella Enteritidis was isolated from the inside of these almond shells in 46 and 100% of the samples, by direct swabbing of the inner surface of the shell and by enrichment from the swab, respectively. These findings suggested that hardness of the shell is not a significant factor in the migration of the pathogen through that tissue. In addition, both motile and nonmotile strains of S. enterica serovar Typhimurium migrated through the almond shells to the same extent under the conditions of this assay, indicating that bacterial migration through the wet shell may be a passive process. Second, whole almonds (intact hull, shell, and kernel) were soaked for 24 to 72 h at 24°C in a suspension of Salmonella Enteritidis phage type 30 labeled with the green fluorescent protein. Green fluorescent protein–labeled Salmonella cells were observed on the outer and inner surfaces of both the almond hull and shell, and on the kernel, by confocal laser scanning microscopy. Our data provide direct evidence that wet conditions allow for Salmonella migration through the hull and shell and onto the almond kernel, thus providing a means by which almond kernels may become contaminated in the field.

scholarly journals Intragenic Antimicrobial Peptide Hs02 Hampers the Proliferation of Single- and Dual-Species Biofilms of P. aeruginosa and S. aureus: A Promising Agent for Mitigation of Biofilm-Associated Infections

2019 ◽  
Vol 20 (14) ◽  
pp. 3604 ◽  
Author(s):  
Lucinda J. Bessa ◽  
Julia R. Manickchand ◽  
Peter Eaton ◽  
José Roberto S. A. Leite ◽  
Guilherme D. Brand ◽  
...  
Keyword(s):  
Antimicrobial Peptide ◽  
Laser Scanning ◽  
Multidrug Resistant ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Antibiofilm Activity ◽  
Bacterial Cells ◽  
Generalized Polarization ◽  
Force Microscopy ◽  
Atomic Force

Pseudomonas aeruginosa and Staphylococcus aureus are two major pathogens involved in a large variety of infections. Their co-occurrence in the same site of infection has been frequently reported and is linked to enhanced virulence and difficulty of treatment. Herein, the antimicrobial and antibiofilm activities of an intragenic antimicrobial peptide (IAP), named Hs02, which was uncovered from the human unconventional myosin 1H protein, were investigated against several P. aeruginosa and S. aureus strains, including multidrug-resistant (MDR) isolates. The antibiofilm activity was evaluated on single- and dual-species biofilms of P. aeruginosa and S. aureus. Moreover, the effect of peptide Hs02 on the membrane fluidity of the strains was assessed through Laurdan generalized polarization (GP). Minimum inhibitory concentration (MIC) values of peptide Hs02 ranged from 2 to 16 μg/mL against all strains and MDR isolates. Though Hs02 was not able to hamper biofilm formation by some strains at sub-MIC values, it clearly affected 24 h preformed biofilms, especially by reducing the viability of the bacterial cells within the single- and dual-species biofilms, as shown by confocal laser scanning microscopy (CLSM) and atomic force microscopy (AFM) images. Laurdan GP values showed that Hs02 induces membrane rigidification in both P. aeruginosa and S. aureus. Peptide Hs02 can potentially be a lead for further improvement as an antibiofilm agent.

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