scholarly journals Contribution of alginate and levan production to biofilm formation by Pseudomonas syringae

Microbiology ◽  
2006 ◽  
Vol 152 (10) ◽  
pp. 2909-2918 ◽  
Author(s):  
Heike Laue ◽  
Alexander Schenk ◽  
Hongqiao Li ◽  
Lotte Lambertsen ◽  
Thomas R. Neu ◽  
...  
Keyword(s):  
Spatial Distribution ◽  
Pseudomonas Syringae ◽  
Biofilm Formation ◽  
Laser Scanning ◽  
Time Course ◽  
Complex Structure ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Bacterial Cells ◽  
Biofilm Development

Exopolysaccharides (EPSs) play important roles in the attachment of bacterial cells to a surface and/or in building and maintaining the three-dimensional, complex structure of bacterial biofilms. To elucidate the spatial distribution and function of the EPSs levan and alginate during biofilm formation, biofilms of Pseudomonas syringae strains with different EPS patterns were compared. The mucoid strain PG4180.muc, which produces levan and alginate, and its levan- and/or alginate-deficient derivatives all formed biofilms in the wells of microtitre plates and in flow chambers. Confocal laser scanning microscopy with fluorescently labelled lectins was applied to investigate the spatial distribution of levan and an additional as yet unknown EPS in flow-chamber biofilms. Concanavalin A (ConA) bound specifically to levan and accumulated in cell-depleted voids in the centres of microcolonies and in blebs. No binding of ConA was observed in biofilms of the levan-deficient mutants or in wild-type biofilms grown in the absence of sucrose as confirmed by an enzyme-linked lectin-sorbent assay using peroxidase-linked ConA. Time-course studies revealed that expression of the levan-forming enzyme, levansucrase, occurred mainly during early exponential growth of both planktonic and sessile cells. Thus, accumulation of levan in biofilm voids hints to a function as a nutrient storage source for later stages of biofilm development. The presence of a third EPS besides levan and alginate was indicated by binding of the lectin from Naja mossambica to a fibrous structure in biofilms of all P. syringae derivatives. Production of the as yet uncharacterized additional EPS might be more important for biofilm formation than the syntheses of levan and alginate.

scholarly journals Bacterial lipopolysaccharides variably modulate in vitro biofilm formation of Candida species

2010 ◽  
Vol 59 (10) ◽  
pp. 1225-1234 ◽  
Author(s):  
H. M. H. N. Bandara ◽  
O. L. T. Lam ◽  
R. M. Watt ◽  
L. J. Jin ◽  
L. P. Samaranayake
Keyword(s):  
Biofilm Formation ◽  
Laser Scanning ◽  
Significant Inhibition ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Dependent Manner ◽  
Bacterial Lipopolysaccharides ◽  
Species Specific ◽  
Biofilm Development

The objective of this study was to evaluate the effect of the bacterial endotoxin LPS on Candida biofilm formation in vitro. The effect of the LPS of Pseudomonas aeruginosa, Klebsiella pneumoniae, Serratia marcescens and Salmonella typhimurium on six different species of Candida, comprising Candida albicans ATCC 90028, Candida glabrata ATCC 90030, Candida krusei ATCC 6258, Candida tropicalis ATCC 13803, Candida parapsilosis ATCC 22019 and Candida dubliniensis MYA 646, was studied using a standard biofilm assay. The metabolic activity of in vitro Candida biofilms treated with LPS at 90 min, 24 h and 48 h was quantified by XTT reduction assay. Viable biofilm-forming cells were qualitatively analysed using confocal laser scanning microscopy (CLSM), while scanning electron microscopy (SEM) was employed to visualize the biofilm structure. Initially, adhesion of C. albicans was significantly stimulated by Pseudomonas and Klebsiella LPS. A significant inhibition of Candida adhesion was noted for the following combinations: C. glabrata with Pseudomonas LPS, C. tropicalis with Serratia LPS, and C. glabrata, C. parapsilosis or C. dubliniensis with Salmonella LPS (P<0.05). After 24 h of incubation, a significant stimulation of initial colonization was noted for the following combinations: C. albicans/C. glabrata with Klebsiella LPS, C. glabrata/C. tropicalis/C. krusei with Salmonella LPS. In contrast, a significant inhibition of biofilm formation was observed in C. glabrata/C. dubliniensis/C. krusei with Pseudomonas LPS, C. krusei with Serratia LPS, C. dubliniensis with Klebsiella LPS and C. parapsilosis/C. dubliniensis /C. krusei with Salmonella LPS (P<0.05). On further incubation for 48 h, a significant enhancement of biofilm maturation was noted for the following combinations: C. glabrata/C. tropicalis with Serratia LPS, C. dubliniensis with Klebsiella LPS and C. glabrata with Salmonella LPS, and a significant retardation was noted for C. parapsilosis/C. dubliniensis/C. krusei with Pseudomonas LPS, C. tropicalis with Serratia LPS, C. glabrata/C. parapsilosis/C. dubliniensis with Klebsiella LPS and C. dubliniensis with Salmonella LPS (P<0.05). These findings were confirmed by SEM and CLSM analyses. In general, the inhibition of the biofilm development of LPS-treated Candida spp. was accompanied by a scanty architecture with a reduced numbers of cells compared with the profuse and densely colonized control biofilms. These data are indicative that bacterial LPSs modulate in vitro Candida biofilm formation in a species-specific and time-dependent manner. The clinical and the biological relevance of these findings have yet to be explored.

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.

scholarly journals Multiple Roles of Biosurfactants in Structural Biofilm Development by Pseudomonas aeruginosa

2007 ◽  
Vol 189 (6) ◽  
pp. 2531-2539 ◽  
Author(s):  
Sünje Johanna Pamp ◽  
Tim Tolker-Nielsen
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Biofilm Formation ◽  
Initial Phase ◽  
Laser Scanning ◽  
Multiple Roles ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Structural Development ◽  
Biofilm Development ◽  
Later Phase

ABSTRACT Recent studies have indicated that biosurfactants produced by Pseudomonas aeruginosa play a role both in maintaining channels between multicellular structures in biofilms and in dispersal of cells from biofilms. Through the use of flow cell technology and enhanced confocal laser scanning microscopy, we have obtained results which suggest that the biosurfactants produced by P. aeruginosa play additional roles in structural biofilm development. We present genetic evidence that during biofilm development by P. aeruginosa, biosurfactants promote microcolony formation in the initial phase and facilitate migration-dependent structural development in the later phase. P. aeruginosa rhlA mutants, deficient in synthesis of biosurfactants, were not capable of forming microcolonies in the initial phase of biofilm formation. Experiments involving two-color-coded mixed-strain biofilms showed that P. aeruginosa rhlA mutants were defective in migration-dependent development of mushroom-shaped multicellular structures in the later phase of biofilm formation. Experiments involving three-color-coded mixed-strain P. aeruginosa biofilms demonstrated that the wild-type and rhlA and pilA mutant strains formed distinct subpopulations on top of each other dependent on their ability to migrate and produce biosurfactants.

scholarly journals Effect of arsenite on swimming motility delays surface colonization in Herminiimonas arsenicoxydans

Microbiology ◽  
2010 ◽  
Vol 156 (8) ◽  
pp. 2336-2342 ◽  
Author(s):  
M. Marchal ◽  
R. Briandet ◽  
S. Koechler ◽  
B. Kammerer ◽  
P. N. Bertin
Keyword(s):  
Laser Scanning ◽  
Time Course ◽  
Wild Type Strain ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Wild Type ◽  
Arsenite Oxidase ◽  
Swimming Motility ◽  
In The Wild ◽  
Biofilm Development

Herminiimonas arsenicoxydans is a Gram-negative bacterium able to detoxify arsenic-contaminated environments by oxidizing arsenite [As(III)] to arsenate [As(V)] and by scavenging arsenic ions in an extracellular matrix. Its motility and colonization behaviour have been previously suggested to be influenced by arsenite. Using time-course confocal laser scanning microscopy, we investigated its biofilm development in the absence and presence of arsenite. Arsenite was shown to delay biofilm initiation in the wild-type strain; this was partly explained by its toxicity, which caused an increased growth lag time. However, this delayed adhesion step in the presence of arsenite was not observed in either a swimming motility defective fliL mutant or an arsenite oxidase defective aoxB mutant; both strains displayed the wild-type surface properties and growth capacities. We propose that during the biofilm formation process arsenite acts on swimming motility as a result of the arsenite oxidase activity, preventing the switch between planktonic and sessile lifestyles. Our study therefore highlights the existence, under arsenite exposure, of a competition between swimming motility, resulting from arsenite oxidation, and biofilm initiation.

scholarly journals The exopolysaccharide–eDNA interaction modulates 3D architecture of Bacillus subtilis biofilm

2020 ◽  
Author(s):  
Na Peng ◽  
Peng Cai ◽  
Monika Mortimer ◽  
Yichao Wu ◽  
Chunhui Gao ◽  
...  
Keyword(s):  
Biofilm Formation ◽  
Laser Scanning ◽  
Laser Scanning Microscopy ◽  
Extracellular Dna ◽  
Titration Calorimetry ◽  
Confocal Laser ◽  
Physical Interaction ◽  
Matrix Components ◽  
Biofilm Development ◽  
Early Phases

Abstract Background Bacterial biofilms are a surface-adherent microbial community in which individual cells are surrounded by a self-produced extracellular matrix of polysaccharide, extracellular DNA (eDNA) and proteins. Interactions among matrix components within the biofilms are responsible for creating an adaptable structure during biofilm development. However, it is unclear how the interaction among matrix components contributes to the construction of the three-dimensional (3D) biofilm architecture. Results DNase I treatment could significantly inhibit B. subtilis biofilm formation in early phases. Confocal laser scanning microscopy (CLSM) and image analysis revealed that eDNA was cooperative with exopolysaccharide (EPS) in early stages of B. subtilis biofilm development, while EPS played a major structural role in the later stages. In addition, deletion of EPS production gene epsG in B. subtilis SBE1 resulted in loss of the interaction between EPS and eDNA, and reduction of biofilm biomass in pellicles at air-liquid interface. The physical interaction between these two essential biofilm matrix components was confirmed by isothermal titration calorimetry (ITC). Conclusions The biofilm 3D structures become interconnected through surrounding eDNA and EPS. eDNA interacts with EPS in the early phases of biofilm development, while EPS mainly participates in the maturation of biofilm. The findings of this study provide better understanding of the role of interaction between eDNA and EPS in shaping the biofilm 3D matrix structure and biofilm formation.

scholarly journals High Adhesion and Increased Cell Death Contribute to Strong Biofilm Formation in Klebsiella pneumoniae

Pathogens ◽  
2019 ◽  
Vol 8 (4) ◽  
pp. 277
Author(s):  
Siddhi Desai ◽  
Kinjal Sanghrajka ◽  
Devarshi Gajjar
Keyword(s):  
Cell Death ◽  
Klebsiella Pneumoniae ◽  
Biofilm Formation ◽  
Laser Scanning ◽  
Laser Scanning Microscopy ◽  
Extracellular Dna ◽  
Confocal Laser ◽  
Bacterial Cells ◽  
High Adhesion ◽  
Biofilm Matrix

Klebsiella pneumoniae (Kp), is a frequent cause of hospital and community-acquired infections and WHO had declared it as a “priority pathogen”. Biofilm is a major virulence factor of Kp and yet the mechanism of strong biofilm formation in Kp is unclear. A key objective of the present study is to investigate the differences between strong and weak biofilms formed by clinical isolates of Kp on various catheters and in different media conditions and to identify constituents contributing to strong biofilm formation. Quantification of matrix components (extracellular DNA (eDNA), protein, exopolysaccharides (EPS), and bacterial cells), confocal laser scanning microscopy (CLSM), field emission gun scanning electron microscopy (FEG-SEM) and flow-cytometry analysis were performed to compare strong and weak biofilm matrix. Our results suggest increased biofilm formation on latex catheters compared to silicone and silicone-coated latex catheters. Higher amounts of eDNA, protein, EPS, and dead cells were observed in the strong biofilm of Kp. High adhesion capacity and cell death seem to play a major role in formation of strong Kp biofilms. The enhanced eDNA, EPS, and protein in the biofilm matrix appear as a consequence of increased cell death.

scholarly journals Contact Effect of a Methylobacterium sp. Extract on Biofilm of a Mycobacterium chimaera Strain Isolated from a 3T Heater-Cooler System

Antibiotics ◽  
2020 ◽  
Vol 9 (8) ◽  
pp. 474
Author(s):  
Inés Pradal ◽  
Jaime Esteban ◽  
Arancha Mediero ◽  
Marta García-Coca ◽  
John Jairo Aguilera-Correa
Keyword(s):  
Biofilm Formation ◽  
Laser Scanning ◽  
Laser Scanning Microscopy ◽  
Trigger Factor ◽  
Confocal Laser ◽  
Membrane Oxygenator ◽  
Extracorporeal Membrane Oxygenator ◽  
Colony Forming Units ◽  
Pre Treatment ◽  
Biofilm Development

Mycobacterium chimaera is an opportunistic slowly growing non-tuberculous mycobacteriumof increasing importance due to the outbreak of cases associated with contaminated 3T heater-cooler device (HCD) extracorporeal membrane oxygenator (ECMO). The aim of this study was to evaluate the effect of pre-treating a surface with a Methylobacterium sp. CECT 7180 extract to inhibit the M. chimaera ECMO biofilm as well as of the treatment after different dehydration times. Surface adherence, biofilm formation and treatment effect were evaluated by estimating colony-forming units (CFU) per square centimeter and characterizing the amount of covered surface area, thickness, cell viability, and presence of intrinsic autofluorescence at different times using confocal laser scanning microscopy and image analysis. We found that exposing a surface to the Methylobacterium sp. CECT 7180 extract inhibited M. chimaera ECMO biofilm development. This effect could be result of the effect of Methylobacterium proteins, such as DNaK, trigger factor, and xanthine oxidase. In conclusion, exposing a surface to the Methylobacteriumsp. extract inhibits M. chimaera ECMO biofilm development. Furthermore, this extract could be used as a pre-treatment prior to disinfection protocols for equipment contaminated with mycobacteria after dehydration for at least 96 h.

scholarly journals Subinhibitory Concentrations of Mupirocin Stimulate Staphylococcus aureus Biofilm Formation by Upregulating cidA

2020 ◽  
Vol 64 (3) ◽  
Author(s):  
Ye Jin ◽  
Yinjuan Guo ◽  
Qing Zhan ◽  
Yongpeng Shang ◽  
Di Qu ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Biofilm Formation ◽  
Laser Scanning ◽  
Multidrug Resistant ◽  
Laser Scanning Microscopy ◽  
Extracellular Dna ◽  
Confocal Laser ◽  
Content Type ◽  
Subinhibitory Concentrations ◽  
Biofilm Development

ABSTRACT Previous studies have shown that the administration of antibiotics at subinhibitory concentrations stimulates biofilm formation by the majority of multidrug-resistant Staphylococcus aureus (MRSA) strains. Here, we investigated the effect of subinhibitory concentrations of mupirocin on biofilm formation by the community-associated (CA) mupirocin-sensitive MRSA strain USA300 and the highly mupirocin-resistant clinical S. aureus SA01 to SA05 isolates. We found that mupirocin increased the ability of MRSA cells to attach to surfaces and form biofilms. Confocal laser scanning microscopy (CLSM) demonstrated that mupirocin treatment promoted thicker biofilm formation, which also correlated with the production of extracellular DNA (eDNA). Furthermore, quantitative real-time PCR (RT-qPCR) results revealed that this effect was largely due to the involvement of holin-like and antiholin-like proteins (encoded by the cidA gene), which are responsible for modulating cell death and lysis during biofilm development. We found that cidA expression levels significantly increased by 6.05- to 35.52-fold (P < 0.01) after mupirocin administration. We generated a cidA-deficient mutant of the USA300 S. aureus strain. Exposure of the ΔcidA mutant to mupirocin did not result in thicker biofilm formation than that in the parent strain. We therefore hypothesize that the mupirocin-induced stimulation of S. aureus biofilm formation may involve the upregulation of cidA.

Farnesol inhibits planktonic cells and antifungal-tolerant biofilms of Trichosporon asahii and Trichosporon inkin

2019 ◽  
Vol 57 (8) ◽  
pp. 1038-1045 ◽  
Author(s):  
Rossana de Aguiar Cordeiro ◽  
Lívia Maria Galdino Pereira ◽  
José Kleybson de Sousa ◽  
Rosana Serpa ◽  
Ana Raquel Colares Andrade ◽  
...  
Keyword(s):  
Biofilm Formation ◽  
Laser Scanning ◽  
Inhibitory Effect ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Planktonic Cells ◽  
Trichosporon Asahii ◽  
Trichosporon Species ◽  
Biofilm Development ◽  
Systemic Infections

Abstract Trichosporon species have been considered important agents of opportunistic systemic infections, mainly among immunocompromised patients. Infections by Trichosporon spp. are generally associated with biofilm formation in invasive medical devices. These communities are resistant to therapeutic antifungals, and therefore the search for anti-biofilm molecules is necessary. This study evaluated the inhibitory effect of farnesol against planktonic and sessile cells of clinical Trichosporon asahii (n = 3) andTrichosporon inkin (n = 7) strains. Biofilms were evaluated during adhesion, development stages and after maturation for metabolic activity, biomass and protease activity, as well as regarding morphology and ultrastructure by optical microscopy, confocal laser scanning microscopy, and scanning electron microscopy. Farnesol inhibited Trichosporon planktonic growth by 80% at concentrations ranging from 600 to 1200 μM for T. asahii and from 75 to 600 μM for T. inkin. Farnesol was able to reduce cell adhesion by 80% at 300 μM for T. asahii and T. inkin at 600 μM, while biofilm development of both species was inhibited by 80% at concentration of 150 μM, altering their structure. After biofilm maturation, farnesol decreased T. asahii biofilm formation by 50% at 600 μM concentration and T. inkin formation at 300 μM. Farnesol inhibited gradual filamentation in a concentration range between 600 and 1200 μM. Farnesol caused reduction of filament structures of Trichosporon spp. at every stage of biofilm development analyzed. These data show the potential of farnesol as an anti-biofilm molecule.

scholarly journals Biofilm Formation by the Fish Pathogen Flavobacterium columnare: Development and Parameters Affecting Surface Attachment

2013 ◽  
Vol 79 (18) ◽  
pp. 5633-5642 ◽  
Author(s):  
Wenlong Cai ◽  
Leonardo De La Fuente ◽  
Covadonga R. Arias
Keyword(s):  
Biofilm Formation ◽  
Laser Scanning ◽  
Time Course ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Freshwater Species ◽  
Flavobacterium Columnare ◽  
Fish Pathogen ◽  
Flow Conditions ◽  
Content Type

ABSTRACTFlavobacterium columnareis a bacterial fish pathogen that affects many freshwater species worldwide. The natural reservoir of this pathogen is unknown, but its resilience in closed aquaculture systems posits biofilm as the source of contagion for farmed fish. The objectives of this study were (i) to characterize the dynamics of biofilm formation and morphology under static and flow conditions and (ii) to evaluate the effects of temperature, pH, salinity, hardness, and carbohydrates on biofilm formation. NineteenF. columnarestrains, including representatives of all of the defined genetic groups (genomovars), were compared in this study. The structure of biofilm was characterized by light microscopy, confocal laser scanning microscopy, and scanning electron microscopy.F. columnarewas able to attach to and colonize inert surfaces by producing biofilm. Surface colonization started within 6 h postinoculation, and microcolonies were observed within 24 h. Extracellular polysaccharide substances and water channels were observed in mature biofilms (24 to 48 h). A similar time course was observed whenF. columnareformed biofilm in microfluidic chambers under flow conditions. The virulence potential of biofilm was confirmed by cutaneous inoculation of channel catfish fingerlings with mature biofilm. Several physicochemical parameters modulate attachment to surfaces, with the largest influence being exerted by hardness, salinity, and the presence of mannose. Maintenance of hardness and salinity values within certain ranges could prevent biofilm formation byF. columnarein aquaculture systems.

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