The impact of cellulose nanocrystals on the aggregation and initial adhesion of Pseudomonas fluorescens bacteria

Soft Matter ◽  
2014 ◽  
Vol 10 (44) ◽  
pp. 8923-8931 ◽  
Author(s):  
Xiaohui Sun ◽  
Qingye Lu ◽  
Yaman Boluk ◽  
Yang Liu

Deposition on silica surfaces of twoPseudomonas fluorescensstrains (CHA0 and CHA19-WS) having different extracellular polymeric substance (EPS) producing capacities was studied in the absence and presence of cellulose nanocrystals (CNCs).

Biofilms ◽  
2005 ◽  
Vol 2 (2) ◽  
pp. 129-144 ◽  
Author(s):  
D. S. Domozych ◽  
S. Kort ◽  
S. Benton ◽  
T. Yu

The desmid Penium margaritaceum is a common resident of biofilms of shallow Adirondack wetlands in New York State, USA. It was isolated and grown in the laboratory where it readily formed biofilms and produced large amounts of extracellular polymeric substance (EPS). The EPS was separated into two fractions: an EPS gel and soluble EPS. Both fractions were rich in xylose, fucose and glucuronic acid. The EPS gels contained large amounts of 3-linked, 4-linked and 3,4-linked fucose, 3,4-linked glucuronic acid and terminal xylose linkages. The EPS gel consisted of a fibrillar matrix that linked cells and cell substrate together. Immunofluorescence analysis using an anti-EPS antibody revealed that EPS secretion occurs in several different modes, which contributes to initial adhesion, capsule formation and gliding.


2020 ◽  
Vol 100 (1) ◽  
pp. 82-89
Author(s):  
C.M.A.P. Schuh ◽  
B. Benso ◽  
P.A. Naulin ◽  
N.P. Barrera ◽  
L. Bozec ◽  
...  

Biofilm-mediated oral diseases such as dental caries and periodontal disease remain highly prevalent in populations worldwide. Biofilm formation initiates with the attachment of primary colonizers onto surfaces, and in the context of caries, the adhesion of oral streptococci to dentinal collagen is crucial for biofilm progression. It is known that dentinal collagen suffers from glucose-associated crosslinking as a function of aging or disease; however, the effect of collagen crosslinking on the early adhesion and subsequent biofilm formation of relevant oral streptococci remains unknown. Therefore, the aim of this work was to determine the impact of collagen glycation on the initial adhesion of primary colonizers such as Streptococcus mutans UA159 and Streptococcus sanguinis SK 36, as well as its effect on the early stages of streptococcal biofilm formation in vitro. Type I collagen matrices were crosslinked with either glucose or methylglyoxal. Atomic force microscopy nanocharacterization revealed morphologic and mechanical changes within the collagen matrix as a function of crosslinking, such as a significantly increased elastic modulus in crosslinked fibrils. Increased nanoadhesion forces were observed for S. mutans on crosslinked collagen surfaces as compared with the control, and retraction curves obtained for both streptococcal strains demonstrated nanoscale unbinding behavior consistent with bacterial adhesin-substrate coupling. Overall, glucose-crosslinked substrates specifically promoted the initial adhesion, biofilm formation, and insoluble extracellular polysaccharide production of S. mutans, while methylglyoxal treatment reduced biofilm formation for both strains. Changes in the adhesion behavior and biofilm formation of oral streptococci as a function of collagen glycation could help explain the biofilm dysbiosis seen in older people and patients with diabetes. Further studies are necessary to determine the influence of collagen crosslinking on the balance between acidogenic and nonacidogenic streptococci to aid in the development of novel preventive and therapeutic treatment against dental caries in these patients.


2021 ◽  
Author(s):  
Ruba F. Farkh

A study was conducted to examine the removal of chlortetracycline and its distribution and accumulation in three compartments; bulk water, extracellular polymeric substance (EPS) and the microbial cells in activated sludge. Also the effect of different environmental conditions on the distribution and accumulation in the three compartments was investigated. Effluent samples collected from a municipal activated sludge treatment system were set up in bath experiments to test the distribution and accumulation of chlortetracycline under aerobic and anoxic conditions for 14 days. In addition, the impact of the activity of the microbial community on the amassing of the antibiotic in the biomass was examined. The effect of divalent cations on import and accumulation of chlortetracycline was tested. Sorption in believed to be the main removal pathway in wastewater treatment systems for tetracyclines in general and chlortetracycline in particular. In this study that notion was confirmed, and it was found that the removal via sorption under anoxic condition (43.2%) is almost double of that under aerobic conditions (27.0%). The amount of what accumulated in the cells compared to that sorbed in the EPS is twice as much in the former and triple as much in the latter. These findings suggest that changes in the structure and charge of the EPS could be the reason of higher accumulation in the polymeric substance. The impact of microbial activity on the sorption and distribution of the chlortetracycline in the three compartments showed almost a similar behaviour to that under aerobic and anoxic conditions. It was clear that the more viable the microbial community, the less the antibiotic accumulated in the [sic] both biomass compartments; the EPS and microbial cells. Biomass with inhibited respiration accrued 90% of the initial concentration; where as the active microbial community was more resistant and only 24.2% of the initial concentration accumulated within the cells. The findings suggest that the antibiotic makes its way to the cells thus bypassing the EPS, and is trapped in the EPS as it is pumped out of the cells in an energy dependent mechanism. The presence of ethylenediaminetetraacetic acid (EDTA) which is a strong chelator had no import effect. Nevertheless it did indicate that the accumulation in the EPS could be attributed to the presence of cations since there was a high negative correlation (-0.98) between the disappearance of the antibiotic from the EPS compartment and the EDTA concentration used in incubation.


2021 ◽  
Vol 22 (8) ◽  
Author(s):  
NURHAYATI DAMIRI ◽  
RIZAL ROFIQI ◽  
MULAWARMAN MULAWARMAN ◽  
SUPLI E. RAHIM ◽  
TRI RAPANI FEBYANTI

Abstract. Damiri N, Rofiqi R, Mulawarnam, Rahim SE, Febyanti TP. 2021. Effect of three composts with active ingredients of Pseudomonas fluorescens on the development of white root disease and production of rubber plants. Biodiversitas 22: 3237-3242. White root disease (WRD) caused by Rigidoporus lignosus is a very dangerous disease and a scourge for rubber farmers because it can result in decreased production and kill rubber plants. This research was conducted to observe the impact of compost enriched with the biological agent Pseudomonas fluorescens on the development of white root disease and production in rubber plants. The results showed that the application of compost with active ingredient of P. fluorescens isolates A and B reduced the severity of white root disease in plants with mild, moderate and severe infections, 34.12%, 29.31% and 57.21% respectively. Application of compost with P. fluorescens isolates A and B, either singly or in combination, can increase latex production. The treatment of giving compost enriched with P. fluorescens isolates AR and ABR on rubber plants infected with mild WRD resulted in the highest latex production of 406 gm and 402.74 gm per plant, respectively. These two treatments did not differ from each other but were significantly different from the other treatments and controls.


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