Surface indentation and fluid intake generated by the polymer matrix of Bacillus subtilis biofilms

Soft Matter ◽  
2015 ◽  
Vol 11 (18) ◽  
pp. 3612-3617 ◽  
Author(s):  
W. Zhang ◽  
W. Dai ◽  
Shi-Ming Tsai ◽  
S. M. Zehnder ◽  
M. Sarntinoranont ◽  
...  
Keyword(s):  
Bacillus Subtilis ◽  
Polymer Matrix ◽  
Fluid Intake ◽  
Elastic Stress ◽  
Force Generation ◽  
Hydraulic Permeability ◽  
Matrix Production

Bacillus subtilisbiofilm force generation is measured. The elastic stress stored in the biofilm's deformed substrate is orders of magnitude larger than the drag stress of pulling fluid into the biofilm, and depends on polymer matrix production. These results reveal that long-term biofouling and colony expansion may depend on the hydraulic permeability and elasticity of colonized surfaces.

scholarly journals Cheaters shape the evolution of phenotypic heterogeneity in Bacillus subtilis biofilms

2018 ◽  
Author(s):  
Marivic Martin ◽  
Anna Dragoš ◽  
Simon B. Otto ◽  
Daniel Schäfer ◽  
Susanne Brix ◽  
...  
Keyword(s):  
Bacillus Subtilis ◽  
Prolonged Exposure ◽  
Adaptive Strategy ◽  
Phenotypic Heterogeneity ◽  
Structural Proteins ◽  
Cell Level ◽  
General Adaptation ◽  
Matrix Production ◽  
Matrix Components

ABSTRACTBiofilms are closely packed cells held and shielded by extracellular matrix composed of structural proteins and exopolysaccharides (EPS). As matrix components are costly to produce and shared within the population, EPS-deficient cells can act as cheaters by gaining benefits from the cooperative nature of EPS producers. Remarkably, genetically programmed EPS producers can also exhibit phenotypic heterogeneity at single cell level. Previous studies have shown that spatial structure of biofilms limits the spread of cheaters, but the long-term influence of cheating on biofilm evolution is not well understood. Here, we examine the influence of EPS non-producers on evolution of matrix production within the populations of EPS producers in a model biofilm-forming bacterium, Bacillus subtilis. We discovered that general adaptation to biofilm lifestyle leads to an increase in phenotypical heterogeneity of eps expression. Apparently, prolonged exposure to EPS-deficient cheaters, may result in different adaptive strategy, where eps expression increases uniformly within the population. We propose a molecular mechanism behind such adaptive strategy and demonstrate how it can benefit the EPS-producers in the presence of cheaters. This study provides additional insights on how biofilms adapt and respond to stress caused by exploitation in long-term scenario.

scholarly journals Degradation of chlorobenzene and 2-chlorotoluene by immobilized bacteria strains Comamonas testosterone kt5 and Bacillus subtilis dkt

2019 ◽  
Vol 41 (4) ◽  
Author(s):  
Ha Danh Duc ◽  
Nguyen Thi Oanh
Keyword(s):  
Bacillus Subtilis ◽  
Bacterial Strain ◽  
Immobilized Cells ◽  
Resting Cells ◽  
Long Term Storage ◽  
Degradation Rates ◽  
Contributory Negligence ◽  
Biofilm Bacteria ◽  
Term Storage

Chlorobenzenes and chlorotoluenes have been used to produce a number of industrial products. They are toxic and widely detected in environments due to human contributory negligence. In this article, the mixed culture of a toluenes-degrading bacterial strain, Comamonas testosterone KT5 (a Gram-positive, catalase-positive bacterium) and a chlorobenzenes-degrading bacterial strain, Bacillus subtilis DKT (a Gram-negative soil bacterium) effectively degraded both chemical compounds co-contaminating in liquid media. In addition, the degradations of mixed compounds by biofilm, bacteria immobilized in polyurethane foam (PUF) and alginate were determined. The results showed that the degradation of both compounds by cells in alginate was significantly higher than that by suspended cells. Moreover, cells immobilized in these materials showed lower adverse effects than those of non-immobilized cells for long-term storage. For examples, the degradation rates for chlorobenzine and 2-chlorotoluene by resting cells reduced by 39.5% and 37.3% after storage for 4 months at 4°C, while the degradation rates by immobilized cells decreased by from 16.3% to 19.8% respectively. 

scholarly journals Quantification of Internal Filtration in Hollow Fiber Hemodialyzers with Medium Cut-Off Membrane

2018 ◽  
Vol 46 (3) ◽  
pp. 196-204 ◽  
Author(s):  
Anna Lorenzin ◽  
Mauro Neri ◽  
Andrea Lupi ◽  
Martina Todesco ◽  
Monica Santimaria ◽  
...  
Keyword(s):  
Nuclear Imaging ◽  
Chronic Hemodialysis ◽  
Transmembrane Pressure ◽  
Hydraulic Permeability ◽  
Dialysate Flow ◽  
New Class ◽  
Inner Diameter ◽  
Marker Molecule

Background: Inadequate removal of molecules between 5 and 50 KDa may cause long-term complication in chronic hemodialysis. Medium cut-off (MCO) is a new class of membranes with enhanced sieving properties and negligible albumin loss. MCO membrane makes it possible to perform expanded hemodialysis (HDx), a technique based on high internal filtration (IF).The present study is designed to quantify IF in 2 MCO dialyzers (Theranova 400 and 500, Baxter, Deerfield, USA) using a nuclear imaging technique previously validated. Methods: Blood and dialysate compartment pressure drop along with transmembrane pressure; they were measured in a closed in vitro circuit with human blood (blood flow [QB] = 300 and 400 mL/min; dialysate flow 500 mL/min; net ultrafiltration rate 0 mL/min). A non-diffusible marker molecule (albumin macro-aggregates labeled with 99Tc metastable) was injected in the blood compartment and nuclear emission was recorded by a gamma camera. Relative variations in the concentration of the marker molecule along the length of the filter were used to calculate local cross filtration. Results: Based on marker concentration profiles, IF was estimated. For Theranova 400, IF were 29.7 and 41.6 mL/min for QB of 300 and 400 mL/min. For Theranova 500, IF were 31.6 and 53.1 mL/min for QB of 300 and 400 mL/min respectively. Conclusions: MCO membrane provides significant amounts of IF due to the particular combination between hydraulic permeability of the membrane and reduced inner diameter of the fibers. High IF combined with enhanced sieving profile of MCO membrane leads to improved removal of a wider spectrum of uremia retention molecules in HDx, without requiring complex equipment.

Bioconvective dynamics: dependence on organism behaviour

2000 ◽  
Vol 203 (21) ◽  
pp. 3345-3354 ◽  
Author(s):  
A. Czirok ◽  
I.M. Janosi ◽  
J.O. Kessler
Keyword(s):  
Bacillus Subtilis ◽  
Cell Density ◽  
Microbial Populations ◽  
Dominant Wavelength ◽  
Nonlinear Convection ◽  
Convection Regime ◽  
Term Evolution ◽  
Convection Patterns ◽  
Micro Organisms

Bioconvection occurs when a macroscopic nonuniformity of the concentration of microbial populations is generated and maintained by the directional swimming of the organisms. This study investigated the properties of the patterns near the onset of the instability and later during its evolution into a fully nonlinear convection regime. In suspensions of the bacteria Bacillus subtilis, which tend to swim upwards in a gradient of oxygen concentration that they create by consumption, we discovered that the dominant wavelength at the onset of the instability is determined primarily by the cell density and is influenced only weakly by the fluid depth. This observation contrasts strongly with previous observations on the gravitactic alga Chlamydomonas nivalis, in which the opposite dependence was found. Considerable differences were also found in the long-term evolution of the convection patterns. These results demonstrate the existence of readily distinguishable types of bioconvection systems, even at early stages of the instability. The observed differences are clearly and causally correlated with disparate reasons for upward swimming by these micro-organisms, leading to different geometric distributions of the density of the suspension.

scholarly journals The Effect of Endophytic Bacteria Bacillus subtilis and Salicylic Acid on Some Resistance and Quality Traits of Stored Solanum tuberosum L. Tubers Infected with Fusarium Dry Rot

Plants ◽  
2020 ◽  
Vol 9 (6) ◽  
pp. 738 ◽  
Author(s):  
Oksana Lastochkina ◽  
Liudmila Pusenkova ◽  
Darya Garshina ◽  
Ruslan Yuldashev ◽  
Irina Shpirnaya ◽  
...  
Keyword(s):  
Bacillus Subtilis ◽  
Salicylic Acid ◽  
Solanum Tuberosum ◽  
Solanum Tuberosum L ◽  
Quality Traits ◽  
Dry Rot ◽  
Long Term Storage ◽  
Fusarium Dry Rot ◽  
Term Storage

The effect of endophytic Bacillus subtilis (strains 10-4, 26D) and their compositions with salicylic acid (SA) on some resistance and quality traits of stored potatoes infected with Fusarium dry rot were studied. The experiments were carried out on hydroponically grown Solanum tuberosum L. tubers that were infected before storage with Fusarium oxysporum and coated with B. subtilis 10-4, 26D with and without exogenous SA, and then stored for six months. It has been shown that 10-4, 26D, 10-4 + SA, and 26D + SA reduced in different levels (up to 30–50%) the incidence of F. oxysporum-caused dry rot (with the highest effect for 10-4 + SA). SA notably enhanced the positive effect of 10-4, while for 26D, such an effect was not observed. All of the tested treatments increased amylase (AMY) and AMY inhibitors activity in infected tubers, while decreased Fusarium-induced protease activity (except in the case of 10-4 + SA, which promoted a slight increase) was revealed. 10-4, 26D, and their compositions with SA decreased (in different degrees) the pathogen-caused lipid peroxidation, proline, and reducing sugars accumulation in potatoes after long-term storage. It was also discovered 10-4 and 26D, regardless of SA presence, decrease pathogen-induced glycoalkaloids α-Solanine and α-Chaconine accumulation and preserved increased levels of starch and total dry matter in infected stored potatoes. The findings indicate endophytic B. subtilis and its compositions with SA is a promising eco-friendly and bio-safe approach to cope with postharvest decays of potato during long-term storage; however, when developing preparations-compositions it should take into account the strain-dependent manner of B. subtilis action together with SA.

scholarly journals Photostability and long-term preservation of a colloidal semiconductor-based single photon emitter in polymeric photonic structures

2019 ◽  
Vol 1 (8) ◽  
pp. 3225-3231 ◽  
Author(s):  
Thi Huong Au ◽  
Stéphanie Buil ◽  
Xavier Quélin ◽  
Jean-Pierre Hermier ◽  
Ngoc Diep Lai
Keyword(s):  
Polymer Matrix ◽  
Single Photon ◽  
Photon Emission ◽  
Single Quantum ◽  
Single Photon Emission ◽  
Quantum Devices ◽  
Protective Polymer ◽  
Single Quantum Dot ◽  
Long Term Preservation

By using a protective polymer matrix, the single photon emission of a single quantum dot becomes perfectly stable. This also opens an excellent accessibility to realisation of photonic quantum devices.

scholarly journals Supporting patients with long-term catheterisation to reduce risk of catheter-associated urinary tract infection

2019 ◽  
Vol 28 (9) ◽  
pp. S4-S17 ◽  
Author(s):  
Anna Waskiewicz ◽  
Obrey Alexis ◽  
Deborah Cross
Keyword(s):  
Urinary Tract Infection ◽  
Urinary Tract ◽  
Tract Infection ◽  
Fluid Intake ◽  
Adult Population ◽  
Personal Hygiene ◽  
Reduce Risk ◽  
The Uk

More than 90 000 of the UK adult population are estimated to have a urinary catheter, with 24% likely to develop symptoms of catheter-associated urinary tract infection (CAUTI). The consequences of having a CAUTI are reduced quality of life, risk of hospitalisation and increased mortality. The authors undertook a literature review of primary research studies to identify how nurses could support patients to maintain effective catheter care to reduce the risk of CAUTI. Four themes emerged: education, knowledge, empowerment and communication. The authors therefore conclude that consistent knowledge, clear communication and treating patients as partners in the decision-making process can help build trust and allow empower patients. This will enable patients to make safe and healthy decisions about their catheter, particularly with regard to personal hygiene and optimal fluid intake, to reducing the risk of CAUTI.

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