scholarly journals Proteins Exported via the PrsD-PrsE Type I Secretion System and the Acidic Exopolysaccharide Are Involved in Biofilm Formation by Rhizobium leguminosarum

2006 ◽  
Vol 188 (12) ◽  
pp. 4474-4486 ◽  
Author(s):  
Daniela M. Russo ◽  
Alan Williams ◽  
Anne Edwards ◽  
Diana M. Posadas ◽  
Christine Finnie ◽  
...  
Keyword(s):  
Biofilm Formation ◽  
Laser Scanning ◽  
Rhizobium Leguminosarum ◽  
Cellular Adhesion ◽  
Secretion System ◽  
Laser Scanning Microscopy ◽  
Secreted Proteins ◽  
Confocal Laser ◽  
Type I ◽  
Biofilm Structure

ABSTRACT The type I protein secretion system of Rhizobium leguminosarum bv. viciae encoded by the prsD and prsE genes is responsible for secretion of the exopolysaccharide (EPS)-glycanases PlyA and PlyB. The formation of a ring of biofilm on the surface of the glass in shaken cultures by both the prsD and prsE secretion mutants was greatly affected. Confocal laser scanning microscopy analysis of green-fluorescent-protein-labeled bacteria showed that during growth in minimal medium, R. leguminosarum wild type developed microcolonies, which progress to a characteristic three-dimensional biofilm structure. However, the prsD and prsE secretion mutants were able to form only an immature biofilm structure. A mutant disrupted in the EPS-glycanase plyB gene showed altered timing of biofilm formation, and its structure was atypical. A mutation in an essential gene for EPS synthesis (pssA) or deletion of several other pss genes involved in EPS synthesis completely abolished the ability of R. leguminosarum to develop a biofilm. Extracellular complementation studies of mixed bacterial cultures confirmed the role of the EPS and the modulation of the biofilm structure by the PrsD-PrsE secreted proteins. Protein analysis identified several additional proteins secreted by the PrsD-PrsE secretion system, and N-terminal sequencing revealed peptides homologous to the N termini of proteins from the Rap family (Rhizobium adhering proteins), which could have roles in cellular adhesion in R. leguminosarum. We propose a model for R. leguminosarum in which synthesis of the EPS leads the formation of a biofilm and several PrsD-PrsE secreted proteins are involved in different aspects of biofilm maturation, such as modulation of the EPS length or mediating attachment between bacteria.

scholarly journals Exopolysaccharide Carbohydrate Structure and Biofilm Formation by Rhizobium leguminosarum bv. trifolii Strains Inhabiting Nodules of Trifoliumrepens Growing on an Old Zn–Pb–Cd-Polluted Waste Heap Area

2021 ◽  
Vol 22 (6) ◽  
pp. 2808
Author(s):  
Ewa Oleńska ◽  
Wanda Małek ◽  
Urszula Kotowska ◽  
Jerzy Wydrych ◽  
Weronika Polińska ◽  
...  
Keyword(s):  
Trifolium Repens ◽  
Biofilm Formation ◽  
Laser Scanning ◽  
Rhizobium Leguminosarum ◽  
Reference Site ◽  
Laser Scanning Microscopy ◽  
Gas Chromatography Mass Spectrometry ◽  
Metal Exposure ◽  
Confocal Laser ◽  
Lead And Cadmium

Heavy metals polluting the 100-year-old waste heap in Bolesław (Poland) are acting as a natural selection factor and may contribute to adaptations of organisms living in this area, including Trifolium repens and its root nodule microsymbionts—rhizobia. Exopolysaccharides (EPS), exuded extracellularly and associated with bacterial cell walls, possess variable structures depending on environmental conditions; they can bind metals and are involved in biofilm formation. In order to examine the effects of long-term exposure to metal pollution on EPS structure and biofilm formation of rhizobia, Rhizobium leguminosarum bv. trifolii strains originating from the waste heap area and a non-polluted reference site were investigated for the characteristics of the sugar fraction of their EPS using gas chromatography mass-spectrometry and also for biofilm formation and structural characteristics using confocal laser scanning microscopy under control conditions as well as when exposed to toxic concentrations of zinc, lead, and cadmium. Significant differences in EPS structure, biofilm thickness, and ratio of living/dead bacteria in the biofilm were found between strains originating from the waste heap and from the reference site, both without exposure to metals and under metal exposure. Received results indicate that studied rhizobia can be assumed as potentially useful in remediation processes.

scholarly journals Nicotine Enhances Interspecies Relationship betweenStreptococcus mutansandCandida albicans

2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
Author(s):  
Shiyu Liu ◽  
Wei Qiu ◽  
Keke Zhang ◽  
Xuedong Zhou ◽  
Biao Ren ◽  
...  
Keyword(s):  
Biofilm Formation ◽  
Laser Scanning ◽  
Laser Scanning Microscopy ◽  
Extracellular Polysaccharides ◽  
Confocal Laser ◽  
Fungal Cell ◽  
Biofilm Model ◽  
Structure Synthesis ◽  
Biofilm Structure ◽  
Synergistic Relationship

Streptococcus mutansandCandida albicansare common microorganisms in the human oral cavity. The synergistic relationship between these two species has been deeply explored in many studies. In the present study, the effect of alkaloid nicotine on the interspecies betweenS. mutansandC. albicansis explored. We developed a dual-species biofilm model and studied biofilm biomass, biofilm structure, synthesis of extracellular polysaccharides (EPS), and expression of glucosyltransferases (Gtfs). Biofilm formation and bacterial and fungal cell numbers in dual-species biofilms increased in the presence of nicotine. MoreC. albicanscells were present in the dual-species biofilms in the nicotine-treated groups as determined by scanning electron microscopy. The synthesis of EPS was increased by 1 mg/ml of nicotine as detected by confocal laser scanning microscopy. The result of qRT-PCR showedgtfsexpression was upregulated when 1 mg/ml of nicotine was used. We speculate that nicotine promoted the growth ofS. mutans, and moreS. mutanscells attracted moreC. albicanscells due to the interaction between two species. SinceS. mutansandC. albicansare putative pathogens for dental caries, the enhancement of the synergistic relationship by nicotine may contribute to caries development in smokers.

scholarly journals Experimental Assessment of the Performance of Two Marine Coatings to Curb Biofilm Formation of Microfoulers

Coatings ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 893 ◽  
Author(s):  
Sara I. Faria ◽  
Rita Teixeira-Santos ◽  
Luciana C. Gomes ◽  
Elisabete R. Silva ◽  
João Morais ◽  
...  
Keyword(s):  
Biofilm Formation ◽  
Laser Scanning ◽  
Critical Role ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Marine Biofouling ◽  
Marine Coatings ◽  
Antifouling Coatings ◽  
Wet Weight ◽  
Biofilm Structure

Biofilms formed on submerged marine surfaces play a critical role in the fouling process, causing increased fuel consumption, corrosion, and high maintenance costs. Thus, marine biofouling is a major issue and motivates the development of antifouling coatings. In this study, the performance of two commercial marine coatings, a foul-release silicone-based paint (SilRef) and an epoxy resin (EpoRef), was evaluated regarding their abilities to prevent biofilm formation by Cyanobium sp. and Pseudoalteromonas tunicata (common microfoulers). Biofilms were developed under defined hydrodynamic conditions to simulate marine settings, and the number of biofilm cells, wet weight, and thickness were monitored for 7 weeks. The biofilm structure was analyzed by confocal laser scanning microscopy (CLSM) at the end-point. Results demonstrated that EpoRef surfaces were effective in inhibiting biofilm formation at initial stages (until day 28), while SilRef surfaces showed high efficacy in decreasing biofilm formation during maturation (from day 35 onwards). Wet weight and thickness analysis, as well as CLSM data, indicate that SilRef surfaces were less prone to biofilm formation than EpoRef surfaces. Furthermore, the efficacy of SilRef surfaces may be dependent on the fouling microorganism, while the performance of EpoRef was strongly influenced by a combined effect of surface and microorganism.

scholarly journals Cold Shock Fail to Restrain Pre-formed Bacterial Biofilm

2018 ◽  
Author(s):  
Wenying Yu ◽  
Qiao Han ◽  
Xueying Song ◽  
Jiaojiao Fu ◽  
Haiquan Liu ◽  
...  
Keyword(s):  
Correlation Analysis ◽  
Biofilm Formation ◽  
Laser Scanning ◽  
Cold Shock ◽  
Bacterial Biofilm ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Structure Parameters ◽  
Cold Environment ◽  
Biofilm Structure

ABSTRACTEnvironmental temperature fluctuation has great impact on the formation of bacterial biofilm, while little information is available for assessing the influence of sharp temperature shifts on the fate of pre-formed biofilm. In this study, experimental evidence is firstly explored on the response ofVibrio parahaemolyticuspre-formed biofilm under cold shock (4 °C and 10 °C). Surprisingly, biofilm biomass ofV. parahaemolyticussignificantly increased during the period of cold shock as revealed by crystal violet staining. Polysaccharides and proteins contents in extracellular polymeric substances were gradually enhanced after cold shocks and exhibited high consistency. RT-qPCR demonstrated the expression of flagella and virulence-related genes were up-regulated. Most of QS and T3SS genes were slightly up-regulated, and three T3SS genes (vcrD1,vcrD2βandvopD1) were down-regulated. Furthermore, the biofilm structure ofV parahaemolyticushave been analyzed by Confocal laser scanning microscopy (CLSM), which sharply changed under cold shocks. The correlation analysis further displayed the significant correlation (P < 0.01) among biofilm structure parameters, and weak correlation (P < 0.05) between biofilm related genes and biofilm structure parameters. In conclusion, our results novel discovered thatV. parahaemolyticusbiofilm related genes were actively expressed and biofilm biomass was continuously increased, biofilm structure was tremendously changed after cold shock. This study underscored the risk that biofilm cells had the ability to adapt to low temperature shift.IMPORTANCEBiofilms are widespread in natural environments, especially on the surface of food and medical biomaterials, which threaten human safety from persistent infections. Previous studies simply focused on biofilm formation of microorganisms under steady state, however, the actual environment frequently fluctuated.V. parahaemolyticusis a widely distributed foodborne pathogen, temperature play a great role in its survival. Researchers generally assume that cold environment can restrain biofilm formation and bacterial activity. This study explored the effects ofV. parahaemolyticusbiofilm upon a shift from 37 °C to 4 °C or 10 °C from two aspects. On the one hand, the changes of biofilm biomass and EPS contents, the expression of biofilm related genes directly described that pre-formed bacterial biofilm could not be controlled efficiently in cold environment. On the other hand, the CLSM images revealed biofilm morphological structure change, the correlation analysis showed inner relationship among biofilm structure parameters and biofilm related genes. These results suggested that cold shock fail to restrain pre-formed bacterial biofilm, therefore be a potential risk in nature environment.

scholarly journals Bacterial Growth on Chitosan-Coated Polypropylene Textile

2012 ◽  
Vol 2012 ◽  
pp. 1-5 ◽  
Author(s):  
D. Erben ◽  
V. Hola ◽  
J. Jaros ◽  
J. Rahel
Keyword(s):  
Biofilm Formation ◽  
Laser Scanning ◽  
Antibacterial Properties ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Aqueous Environment ◽  
Bacterial Enumeration ◽  
Pressure Development ◽  
Barrier Discharge Plasma ◽  
Biofilm Structure

Biofouling is a problem common in all systems where microorganisms and aqueous environment meet. Prevention of biofouling is therefore important in many industrial processes. The aim of this study was to develop a method to evaluate the ability of material coating to inhibit biofilm formation. Chitosan-coated polypropylene nonwoven textile was prepared using dielectric barrier discharge plasma activation. Resistance of the textile to biofouling was then tested. First, the textile was submerged into a growth medium inoculated with green fluorescein protein labelled Pseudomonas aeruginosa. After overnight incubation at 33°C, the textile was observed using confocal laser scanning microscopy for bacterial enumeration and biofilm structure characterisation. In the second stage, the textile was used as a filter medium for prefiltered river water, and the pressure development on the in-flow side was measured to quantify the overall level of biofouling. In both cases, nontreated textile samples were used as a control. The results indicate that the chitosan coating exhibits antibacterial properties. The developed method is applicable for the evaluation of the ability to inhibit biofilm formation.

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 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.

scholarly journals Using micro-patterned surfaces to inhibit settlement and biofilm formation by Bacillus subtilis

2017 ◽  
Vol 63 (7) ◽  
pp. 608-620 ◽  
Author(s):  
Siyuan Chang ◽  
Xiaodong Chen ◽  
Shuo Jiang ◽  
Jinchun Chen ◽  
Lin Shi
Keyword(s):  
Bacillus Subtilis ◽  
Biofilm Formation ◽  
Laser Scanning ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Patterned Surfaces ◽  
Heat Transfer Efficiency ◽  
Treated Sewage ◽  
Different Characteristics ◽  
Precision Balance

Biofilm is a biological complex caused by bacteria attachment to the substrates and their subsequent reproduction and secretion. This phenomenon reduces heat transfer efficiency and causes significant losses in treated sewage heat-recovering systems. This paper describes a physical approach to inhibit bacteria settlement and biofilm formation by Bacillus subtilis, which is the dominant species in treated sewage. Here, micro-patterned surfaces with different characteristics (stripe and cube) and dimensions (1–100 μm) were fabricated as surfaces of interest. Model sewage was prepared and a rotating coupon device was used to form the biofilms. Precision balance, scanning electron microscopy, and confocal laser scanning microscopy (CLSM) were employed to investigate the inhibitory effects and the mechanisms of the biofilm–surface interactions. The results have shown that surfaces with small pattern sizes (1 and 2 μm) all reduced biofilm formation significantly. Interestingly, the CLSM images showed that the surfaces do not play a role in “killing” the bacteria. These findings are useful for future development of new process surfaces on which bacteria settlement and biofilm formation can be inhibited or minimized.

scholarly journals Inhibition of Quorum Sensing and Biofilm Formation of Esculetin on Aeromonas Hydrophila

2021 ◽  
Vol 12 ◽  
Author(s):  
Bing Sun ◽  
Huaizhi Luo ◽  
Huan Jiang ◽  
Zhennan Wang ◽  
Aiqun Jia
Keyword(s):  
Quorum Sensing ◽  
Aeromonas Hydrophila ◽  
Biofilm Formation ◽  
Laser Scanning ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Pcr Analysis ◽  
Swarming Motility ◽  
Gene Expression Levels ◽  
Good Agreement

Quorum sensing (QS) and biofilm formation inhibition activity of esculetin on Aeromonas hydrophila SHAe 115 were evaluated. Exposure to esculetin at 25, 50, and 100μg/ml significantly inhibited the production of protease and hemolysin, the formation of biofilms and attenuated the swarming motility of A. hydrophila SHAe 115. Biofilm forming inhibition was also observed through confocal laser scanning microscopy and scanning electron microscope. Quantitative real-time PCR analysis indicated that genes positively related to QS and biofilm formation were downregulated to varying degrees, while gene (litR) negatively related to biofilm formation was significantly upregulated. The phenotypic results were in good agreement with gene expression levels. These results indicated that esculetin would be a potential QS inhibitor for A. hydrophila.

scholarly journals The Interaction of N-Acetylcysteine and Serum Transferrin Promotes Bacterial Biofilm Formation

2018 ◽  
Vol 45 (4) ◽  
pp. 1399-1409 ◽  
Author(s):  
Supeng Yin ◽  
Bei Jiang ◽  
Guangtao Huang ◽  
Yulong Zhang ◽  
Bo You ◽  
...  
Keyword(s):  
Human Serum ◽  
Biofilm Formation ◽  
Laser Scanning ◽  
Serum Proteins ◽  
Venous Catheter ◽  
Bacterial Biofilm ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Bacterial Strains

Background/Aims: N-acetylcysteine (NAC) is a novel and promising agent with activity against bacterial biofilms. Human serum also inhibits biofilm formation by some bacteria. We tested whether the combination of NAC and human serum offers greater anti-biofilm activity than either agent alone. Methods: Microtiter plate assays and confocal laser scanning microscopy were used to evaluate bacterial biofilm formation in the presence of NAC and human serum. qPCR was used to examine expression of selected biofilm-associated genes. Extracellular matrix (ECM) was observed by transmission electron microscopy. The antioxidants GSH or ascorbic acid were used to replace NAC, and human transferrin, lactoferrin, or bovine serum albumin were used to replace serum proteins in biofilm formation assays. A rat central venous catheter model was developed to evaluate the effect of NAC on biofilm formation in vivo. Results: NAC and serum together increased biofilm formation by seven different bacterial strains. In Staphylococcus aureus, expression of genes for some global regulators and for genes in the ica-dependent pathway increased markedly. In Pseudomonas aeruginosa, transcription of las, the PQS quorum sensing (QS) systems, and the two-component system GacS/GacA increased significantly. ECM production by S. aureus and P. aeruginosa was also enhanced. The potentiation of biofilm formation is due mainly to interaction between NAC and transferrin. Intravenous administration of NAC increased colonization by S. aureus and P. aeruginosa on implanted catheters. Conclusions: NAC used intravenously or in the presence of blood increases bacterial biofilm formation rather than inhibits it.

Sign in / Sign up

Export Citation Format

Share Document