scholarly journals Bactericidal compounds controlling growth of the plant pathogen pseudomonas syringae pv. actinidiae, which forms biofilms composed of a novel exopolysaccharide

2020 ◽  
Author(s):  
S Ghods ◽  
Ian Sims ◽  
MF Moradali ◽  
BHA Rehma
Keyword(s):  
Pseudomonas Syringae ◽  
Chlorine Dioxide ◽  
Laser Scanning ◽  
Extracellular Polymeric Substances ◽  
Virulent Strain ◽  
Bactericidal Effect ◽  
Cell System ◽  
Laser Scanning Microscopy ◽  
Base Layer ◽  
Confocal Laser

© 2015, American Society for Microbiology. Pseudomonas syringae pv. actinidiae is the major cause of bacterial canker and is a severe threat to kiwifruit production worldwide. Many aspects of the disease caused by P. syringae pv. actinidiae, such as the pathogenicity-relevant formation of a biofilm composed of extracellular polymeric substances (EPSs), are still unknown. Here, a highly virulent strain of P. syringae pv. actinidiae, NZ V-13, was studied with respect to biofilm formation and architecture using a flow cell system combined with confocal laser scanning microscopy. The biofilm formed by P. syringae pv. actinidiae NZ V-13 was heterogeneous, consisting of a thin cellular base layer 5 μm thick and microcolonies with irregular structures. The major component of the EPSs produced by P. syringae pv. actinidiae NZ V-13 bacteria was isolated and identified to be an exopolysaccharide. Extensive compositional and structural analysis showed that rhamnose, fucose, and glucose were the major constituents, present at a ratio of 5:1.5:2. Experimental evidence that P. syringae pv. actinidiae NZ V-13 produces two polysaccharides, a branched α-D-rhamnan with side chains of terminal α-D-Fucf and an α-D-1,4-linked glucan, was obtained. The susceptibility of the cells in biofilms to kasugamycin and chlorine dioxide was assessed. About 64 and 73% of P. syringae pv. actinidiae NZ V-13 cells in biofilms were killed when kasugamycin and chlorine dioxide were used at 5 and 10 ppm, respectively. Kasugamycin inhibited the attachment of P. syringae pv. actinidiae NZ V-13 to solid surfaces at concentrations of 80 and 100 ppm. Kasugamycin was bacteriostatic against P. syringae pv. actinidiae NZ V-13 growth in the planktonic mode, with the MIC being 40 to 60 ppm and a bactericidal effect being found at 100 ppm. Here we studied the formation, architecture, and composition of P. syringae pv. actinidiae biofilms as well as used the biofilm as a model to assess the efficacies of bactericidal compounds.

scholarly journals Bactericidal compounds controlling growth of the plant pathogen pseudomonas syringae pv. actinidiae, which forms biofilms composed of a novel exopolysaccharide

2020 ◽  
Author(s):  
S Ghods ◽  
Ian Sims ◽  
MF Moradali ◽  
BHA Rehma
Keyword(s):  
Pseudomonas Syringae ◽  
Chlorine Dioxide ◽  
Laser Scanning ◽  
Extracellular Polymeric Substances ◽  
Virulent Strain ◽  
Bactericidal Effect ◽  
Cell System ◽  
Laser Scanning Microscopy ◽  
Base Layer ◽  
Confocal Laser

© 2015, American Society for Microbiology. Pseudomonas syringae pv. actinidiae is the major cause of bacterial canker and is a severe threat to kiwifruit production worldwide. Many aspects of the disease caused by P. syringae pv. actinidiae, such as the pathogenicity-relevant formation of a biofilm composed of extracellular polymeric substances (EPSs), are still unknown. Here, a highly virulent strain of P. syringae pv. actinidiae, NZ V-13, was studied with respect to biofilm formation and architecture using a flow cell system combined with confocal laser scanning microscopy. The biofilm formed by P. syringae pv. actinidiae NZ V-13 was heterogeneous, consisting of a thin cellular base layer 5 μm thick and microcolonies with irregular structures. The major component of the EPSs produced by P. syringae pv. actinidiae NZ V-13 bacteria was isolated and identified to be an exopolysaccharide. Extensive compositional and structural analysis showed that rhamnose, fucose, and glucose were the major constituents, present at a ratio of 5:1.5:2. Experimental evidence that P. syringae pv. actinidiae NZ V-13 produces two polysaccharides, a branched α-D-rhamnan with side chains of terminal α-D-Fucf and an α-D-1,4-linked glucan, was obtained. The susceptibility of the cells in biofilms to kasugamycin and chlorine dioxide was assessed. About 64 and 73% of P. syringae pv. actinidiae NZ V-13 cells in biofilms were killed when kasugamycin and chlorine dioxide were used at 5 and 10 ppm, respectively. Kasugamycin inhibited the attachment of P. syringae pv. actinidiae NZ V-13 to solid surfaces at concentrations of 80 and 100 ppm. Kasugamycin was bacteriostatic against P. syringae pv. actinidiae NZ V-13 growth in the planktonic mode, with the MIC being 40 to 60 ppm and a bactericidal effect being found at 100 ppm. Here we studied the formation, architecture, and composition of P. syringae pv. actinidiae biofilms as well as used the biofilm as a model to assess the efficacies of bactericidal compounds.

scholarly journals Bactericidal Compounds Controlling Growth of the Plant Pathogen Pseudomonas syringae pv. actinidiae, Which Forms Biofilms Composed of a Novel Exopolysaccharide

2015 ◽  
Vol 81 (12) ◽  
pp. 4026-4036 ◽  
Author(s):  
Shirin Ghods ◽  
Ian M. Sims ◽  
M. Fata Moradali ◽  
Bernd H. A. Rehm
Keyword(s):  
Pseudomonas Syringae ◽  
Chlorine Dioxide ◽  
Laser Scanning ◽  
Extracellular Polymeric Substances ◽  
Virulent Strain ◽  
Cell System ◽  
Laser Scanning Microscopy ◽  
Base Layer ◽  
Confocal Laser ◽  
Content Type

ABSTRACTPseudomonas syringaepv. actinidiae is the major cause of bacterial canker and is a severe threat to kiwifruit production worldwide. Many aspects of the disease caused byP. syringaepv. actinidiae, such as the pathogenicity-relevant formation of a biofilm composed of extracellular polymeric substances (EPSs), are still unknown. Here, a highly virulent strain ofP. syringaepv. actinidiae, NZ V-13, was studied with respect to biofilm formation and architecture using a flow cell system combined with confocal laser scanning microscopy. The biofilm formed byP. syringaepv. actinidiae NZ V-13 was heterogeneous, consisting of a thin cellular base layer 5 μm thick and microcolonies with irregular structures. The major component of the EPSs produced byP. syringaepv. actinidiae NZ V-13 bacteria was isolated and identified to be an exopolysaccharide. Extensive compositional and structural analysis showed that rhamnose, fucose, and glucose were the major constituents, present at a ratio of 5:1.5:2. Experimental evidence thatP. syringaepv. actinidiae NZ V-13 produces two polysaccharides, a branched α-d-rhamnan with side chains of terminal α-d-Fucfand an α-d-1,4-linked glucan, was obtained. The susceptibility of the cells in biofilms to kasugamycin and chlorine dioxide was assessed. About 64 and 73% ofP. syringaepv. actinidiae NZ V-13 cells in biofilms were killed when kasugamycin and chlorine dioxide were used at 5 and 10 ppm, respectively. Kasugamycin inhibited the attachment ofP. syringaepv. actinidiae NZ V-13 to solid surfaces at concentrations of 80 and 100 ppm. Kasugamycin was bacteriostatic againstP. syringaepv. actinidiae NZ V-13 growth in the planktonic mode, with the MIC being 40 to 60 ppm and a bactericidal effect being found at 100 ppm. Here we studied the formation, architecture, and composition ofP. syringaepv. actinidiae biofilms as well as used the biofilm as a model to assess the efficacies of bactericidal compounds.

scholarly journals Sequential Treatment of Biofilms with Aztreonam and Tobramycin Is a Novel Strategy for Combating Pseudomonas aeruginosa Chronic Respiratory Infections

2016 ◽  
Vol 60 (5) ◽  
pp. 2912-2922 ◽  
Author(s):  
Estrella Rojo-Molinero ◽  
María D. Macià ◽  
Rosa Rubio ◽  
Bartolomé Moyà ◽  
Gabriel Cabot ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Laser Scanning ◽  
Bactericidal Effect ◽  
Cell System ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Antibiofilm Activity ◽  
Content Type ◽  
Inhaled Antibiotics ◽  
Resistant Mutants

ABSTRACTTraditional therapeutic strategies to control chronic colonization in cystic fibrosis (CF) patients are based on the use of a single nebulized antibiotic. In this study, we evaluated the therapeutic efficacy and dynamics of antibiotic resistance inPseudomonas aeruginosabiofilms under sequential therapy with inhaled aztreonam (ATM) and tobramycin (TOB). Laboratory strains PAO1, PAOMS (hypermutable), PAOMA (mucoid), and PAOMSA (mucoid and hypermutable) and two hypermutable CF strains, 146-HSE (Liverpool epidemic strain [LES-1]) and 1089-HSE (ST1089), were used. Biofilms were developed using the flow cell system. Mature biofilms were challenged with peak and 1/10-peak concentrations of ATM (700 mg/liter and 70 mg/liter), TOB (1,000 mg/liter and 100 mg/liter), and their alternations (ATM/TOB/ATM and TOB/ATM/TOB) for 2 (t= 2), 4 (t= 4), and 6 days (t= 6). The numbers of viable cells (CFU) and resistant mutants were determined. Biofilm structural dynamics were monitored by confocal laser scanning microscopy and processed with COMSTAT and IMARIS software programs. TOB monotherapy produced an intense decrease in CFU that was not always correlated with a reduction in biomass and/or a bactericidal effect on biofilms, particularly for the CF strains. The ATM monotherapy bactericidal effect was lower, but effects on biofilm biomass and/or structure, including intense filamentation, were documented. The alternation of TOB and ATM led to an enhancement of the antibiofilm activity against laboratory and CF strains compared to that with the individual regimens, potentiating the bactericidal effect and/or the reduction in biomass, particularly at peak concentrations. Resistant mutants were not documented in any of the regimens at the peak concentrations and only anecdotally at the 1/10-peak concentrations. These results support the clinical evaluation of sequential regimens with inhaled antibiotics in CF, as opposed to the current maintenance treatments with just one antibiotic in monotherapy.

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 Raman Spectroscopic Characterization of Endodontic Biofilm Matrices

2019 ◽  
Vol 2019 ◽  
pp. 1-7 ◽  
Author(s):  
Tatiana Ramirez-Mora ◽  
Claudia Dávila-Pérez ◽  
Fernando Torres-Méndez ◽  
Grettel Valle-Bourrouet
Keyword(s):  
Raman Spectroscopy ◽  
Laser Scanning ◽  
Extracellular Polymeric Substances ◽  
Principal Component ◽  
Spectroscopic Characterization ◽  
Laser Scanning Microscopy ◽  
Confocal Scanning Laser Microscopy ◽  
Confocal Laser ◽  
Total Biomass ◽  
Endodontic Infections

Endodontic persistent infections are often mediated by bacterial biofilms. This mode of bacterial growth is characterized by the presence of a matrix mainly composed of extracellular polymeric substances (EPSs) that protect the encased microorganisms. To establish better control and disinfection protocols, elucidation of the main components of biofilm matrices present in endodontic infections is required. The aim of the present study was to characterize the principal components ofE. faecalis,A. naeslundii, and dual-species biofilm matrices by means of Raman spectroscopy and confocal scanning laser microscopy (CSLM) techniques. The total biomass of biofilms was quantified via crystal violet assays, and the monospecies biofilms showed higher biomass than the dual-species biofilms. Raman spectroscopy and confocal laser scanning microscopy were used to identify the biochemical composition and structure of the biofilm matrices. Spectra originating from the biofilms of two endodontic pathogens show the presence of carbohydrates, proteins, fatty acids, and nucleic acids in all samples; however, variation in the levels of expression of these biomolecules allows spectroscopic differentiation of the biofilms using principal component analysis. This study is the first attempt to identify the composition of monospecies and dual-species biofilms of endodontic origin. Our data provides an important approach to the understanding of molecular dynamics of endodontic infections.

scholarly journals Effects of Operational Parameters on Biofilm Formation of Mixed Bacteria for Hydrogen Fermentation

2020 ◽  
Vol 12 (21) ◽  
pp. 8863
Author(s):  
Jie Mei ◽  
Huize Chen ◽  
Qiang Liao ◽  
Abdul-Sattar Nizami ◽  
Ao Xia ◽  
...  
Keyword(s):  
Formation Process ◽  
Biofilm Formation ◽  
Laser Scanning ◽  
Extracellular Polymeric Substances ◽  
Packed Bed ◽  
Dark Fermentation ◽  
Laser Scanning Microscopy ◽  
Packed Bed Reactor ◽  
Confocal Laser ◽  
Operational Parameters

Dark fermentation of organic wastes, such as food waste and algae, via mixed hydrogen-producing bacteria (HPB) is considered a sustainable approach for hydrogen production. The biofilm system protects microorganisms from the harmful environment and avoids the excessive loss of bacteria caused by washout, which ensures that the dark fermentation process remains stable. In this study, a downflow anaerobic packed-bed reactor was commissioned to investigate the biofilm formation process of mixed HPB under various operational parameters. Scanning electron microscopy indicated changes in surface morphology during the biofilm formation period. Proteins and polysaccharides in extracellular polymeric substances were identified by confocal laser scanning microscopy to reveal their distribution characteristics. A hydraulic retention time of 0.5 d, a substrate concentration of 15 g/L and an HPB inoculum ratio of 35% were identified as the optimal operational parameters for biofilm formation. The diversity of bacteria between suspension and biofilm showed significantly different distributions; Clostridiales and Lactobacillales were identified as the dominant orders in the biofilm formation process. The abundances of Clostridiales and Lactobacillales were 15.1% and 56.2% in the biofilm, respectively.

scholarly journals Enhanced Bactericidal Efficacy of NaOCl at pH 12 Followed by Acidified NaOCl at pH 6.5 on Enterococcus faecalis Biofilm

2020 ◽  
Vol 10 (17) ◽  
pp. 6096
Author(s):  
Ronald Wigler ◽  
Shlomo Matalon ◽  
Tomer Goldberger ◽  
Anat Or Lerner ◽  
Anda Kfir
Keyword(s):  
Contact Time ◽  
Laser Scanning ◽  
Saline Solution ◽  
Volume Ratio ◽  
Bactericidal Effect ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Red Fluorescence ◽  
Bactericidal Efficacy ◽  
Significant Difference

This study aimed to determine the bactericidal efficacy of sequential use of NaOCl pH 12 followed by acidified NaOCl pH 6.5, and compare it to that of either of these NaOCl solutions alone. E. faecalis biofilm was grown on standardized dentine specimens for four weeks. The specimens were randomly divided into four groups: (A) 4 min exposure to 0.9% saline solution (control); (B) 4 min exposure to 4% NaOCl pH 12; (C) 4 min exposure to 4% NaOCl pH 6.5; and (D) 2 min exposure to 4% NaOCl pH 12 followed by 2 min exposure to 4% NaOCl pH 6.5. The bactericidal activity was evaluated after the 4 min of contact time using confocal laser scanning microscopy. The volume ratio of red fluorescence to green and red fluorescence indicated the proportion of dead cells in the biofilm. The percent of dead cells in the saline solution group was significantly lower than those in the other groups. There was no significant difference between NaOCl pH 12 compared to NaOCl pH 6.5. The sequential use of NaOCl pH 12 followed by pH 6.5 significantly increased the percent of dead cells compared to both the samples exposed to either NaOCl pH 12 or pH 6.5. These results show that sequential irrigation protocol had a stronger bactericidal effect than the commonly used NaOCl pH 12.

scholarly journals Microbial Composition and Structure of Aerobic Granular Sewage Biofilms

2007 ◽  
Vol 73 (19) ◽  
pp. 6233-6240 ◽  
Author(s):  
S. D. Weber ◽  
W. Ludwig ◽  
K.-H. Schleifer ◽  
J. Fried
Keyword(s):  
Activated Sludge ◽  
Laser Scanning ◽  
Extracellular Polymeric Substances ◽  
Phase 1 ◽  
Simultaneous Detection ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Microbial Composition ◽  
Granule Formation ◽  
Biofilm Development

ABSTRACT Aerobic activated sludge granules are dense, spherical biofilms which can strongly improve purification efficiency and sludge settling in wastewater treatment processes. In this study, the structure and development of different granule types were analyzed. Biofilm samples originated from lab-scale sequencing batch reactors which were operated with malthouse, brewery, and artificial wastewater. Scanning electron microscopy, light microscopy, and confocal laser scanning microscopy together with fluorescence in situ hybridization (FISH) allowed insights into the structure of these biofilms. Microscopic observation revealed that granules consist of bacteria, extracellular polymeric substances (EPS), protozoa and, in some cases, fungi. The biofilm development, starting from an activated sludge floc up to a mature granule, follows three phases. During phase 1, stalked ciliated protozoa of the subclass Peritrichia, e.g., Epistylis spp., settle on activated sludge flocs and build tree-like colonies. The stalks are subsequently colonized by bacteria. During phase 2, the ciliates become completely overgrown by bacteria and die. Thereby, the cellular remnants of ciliates act like a backbone for granule formation. During phase 3, smooth, compact granules are formed which serve as a new substratum for unstalked ciliate swarmers settling on granule surfaces. These mature granules comprise a dense core zone containing bacterial cells and EPS and a loosely structured fringe zone consisting of either ciliates and bacteria or fungi and bacteria. Since granules can grow to a size of up to several millimeters in diameter, we developed and applied a modified FISH protocol for the study of cryosectioned biofilms. This protocol allows the simultaneous detection of bacteria, ciliates, and fungi in and on granules.

Alginate production affects Pseudomonas aeruginosa biofilm development and architecture, but is not essential for biofilm formation

2004 ◽  
Vol 53 (7) ◽  
pp. 679-690 ◽  
Author(s):  
Andres Plata Stapper ◽  
Giri Narasimhan ◽  
Dennis E. Ohman ◽  
Johnny Barakat ◽  
Morten Hentzer ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Biofilm Formation ◽  
Laser Scanning ◽  
Fluorescent Protein ◽  
Cell System ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Alginate Production ◽  
Green Fluorescent ◽  
Biofilm Development

Extracellular polymers can facilitate the non-specific attachment of bacteria to surfaces and hold together developing biofilms. This study was undertaken to qualitatively and quantitatively compare the architecture of biofilms produced by Pseudomonas aeruginosa strain PAO1 and its alginate-overproducing (mucA22) and alginate-defective (algD) variants in order to discern the role of alginate in biofilm formation. These strains, PAO1, Alg+ PAOmucA22 and Alg− PAOalgD, tagged with green fluorescent protein, were grown in a continuous flow cell system to characterize the developmental cycles of their biofilm formation using confocal laser scanning microscopy. Biofilm Image Processing (bip) and Community Statistics (comstat) software programs were used to provide quantitative measurements of the two-dimensional biofilm images. All three strains formed distinguishable biofilm architectures, indicating that the production of alginate is not critical for biofilm formation. Observation over a period of 5 days indicated a three-stage development pattern consisting of initiation, establishment and maturation. Furthermore, this study showed that phenotypically distinguishable biofilms can be quantitatively differentiated.

Sign in / Sign up

Export Citation Format

Share Document