Effects of carbon to nitrogen ratios on amounts and composition of Bacillus subtilis biofilms

2020 ◽  
Author(s):  
Natalia Cortes Osorio ◽  
Robert Endrika ◽  
Karsten Kalbitz ◽  
Cordula Vogel
Keyword(s):  
Bacillus Subtilis ◽  
Extracellular Polymeric Substances ◽  
High Vacuum ◽  
Chemical Properties ◽  
High Ratio ◽  
Natural Environments ◽  
Radial Expansion ◽  
Biofilm Growth ◽  
Microbial Cells ◽  
Biofilm Development

<p>In natural environments, bacteria can be found as multicellular communities exhibiting a high degree of structure, denominated biofilms. Biofilms are composed of microbial cells, often of multiple species, embedded within a matrix of extracellular polymeric substances (EPS). The exact composition, physical and chemical properties, and amounts of these components varies depending on their growth conditions. However, it remains unclear how nutrient availability drives the allocation into cell growth or EPS production, especially under conditions found in soils. Here we aimed to evaluate the effect of various C/N ratios on <em>Bacillus subtilis</em> biofilm growth (spatial expansion and structure) and their EPS composition. We hypothesized that the largest biofilm development and highest EPS production by <em>Bacillus subtilis</em> would be caused by a nutrient imbalance reflected in C/N ratios, especially high C availability. Biofilms were grown on membranes on MSgg agar plates with C/N ratios of 1:1, 10:1, 25:1 and 100:1. Several methods from macroscopic observations over EPS extraction and determination up to various microscopic visualisation techniques were used. The radial expansion of the biofilm was measured, followed by EPS extraction to quantify EPS-proteins and EPS-polysaccharides. Hydrated biofilm samples were studied regarding their biofilm structures by scanning electron microscopy (SEM) within the environmental mode at approximately 97% humidity. Fixed, dehydrated and embedded samples were used to evaluate the biofilm height and internal structure with SEM in high vacuum mode. Low C/N ratio (1:1) resulted in the smallest biofilms in terms of radial expansion and biofilm height, with densely packed layers of cells and low amounts of EPS. Our first results revealed that the highest biofilm productions were observed at C/N ratio of 10:1 and 25:1. The microscopic approaches indicated that biofilms growing at C/N ratios of 100:1 produced the highest amount of EPS. Furthermore, changes in the microscopical features of the biofilms were detected with different structures along the biofilm regions affected by the nutrient conditions. These results suggest that the C/N ratio has a large impact on the biofilm development and structure, with different allocations into microbial cells and EPS. Overall, the results obtained until now allowed us to accept the initial hypothesis, indicating that higher C/N ratios induce a higher EPS production. This suggests that environments containing a high ratio between carbon and the limiting nutrient, often nitrogen, may favour polysaccharide production, probably because energy from the carbon excess is used for polysaccharide biosynthesis.</p>

scholarly journals Impact of flow velocity on biochemical processes – a laboratory experiment

2014 ◽  
Vol 11 (8) ◽  
pp. 9829-9862 ◽  
Author(s):  
A. Boisson ◽  
D. Roubinet ◽  
L. Aquilina ◽  
O. Bour ◽  
P. Davy
Keyword(s):  
Laboratory Experiment ◽  
Flow Velocity ◽  
Chemical Properties ◽  
Reaction Rates ◽  
Natural Environments ◽  
Biochemical Reactions ◽  
Mobile Electron ◽  
Immobile Phase ◽  
Biofilm Development ◽  
The Impact

Abstract. Understanding and predicting hydraulic and chemical properties of natural environments are current crucial challenges. It requires considering hydraulic, chemical and biological processes and evaluating how hydrodynamic properties impact on biochemical reactions. In this context, an original laboratory experiment to study the impact of flow velocity on biochemical reactions along a one-dimensional flow streamline has been developed. Based on the example of nitrate reduction, nitrate-rich water passes through plastic tubes at several flow velocities (from 6.2 to 35 mm min−1), while nitrate concentration at the tube outlet is monitored for more than 500 h. This experimental setup allows assessing the biologically controlled reaction between a mobile electron acceptor (nitrate) and an electron donor (carbon) coming from an immobile phase (tube) that produces carbon during its degradation by microorganisms. It results in observing a dynamic of the nitrate transformation associated with biofilm development which is flow-velocity dependent. It is proposed that the main behaviors of the reaction rates are related to phases of biofilm development through a simple analytical model including assimilation. Experiment results and their interpretation demonstrate a significant impact of flow velocity on reaction performance and stability and highlight the relevance of dynamic experiments over static experiments for understanding biogeochemical processes.

scholarly journals Flow-induced symmetry breaking in growing bacterial biofilms

2019 ◽  
Author(s):  
Philip Pearce ◽  
Boya Song ◽  
Dominic J. Skinner ◽  
Rachel Mok ◽  
Raimo Hartmann ◽  
...  
Keyword(s):  
Developmental Stages ◽  
Bacterial Biofilms ◽  
Natural Environments ◽  
Bacterial Cells ◽  
Cell Orientation ◽  
Biofilm Growth ◽  
Time Resolved ◽  
Microbial Life ◽  
Biofilm Development ◽  
Life On Earth

AbstractBacterial biofilms represent a major form of microbial life on Earth and serve as a model active nematic system, in which activity results from growth of the rod-shaped bacterial cells. In their natural environments, ranging from human organs to industrial pipelines, biofilms have evolved to grow robustly under significant fluid shear. Despite intense practical and theoretical interest, it is unclear how strong fluid flow alters the local and global architectures of biofilms. Here, we combine highly time-resolved single-cell live imaging with 3D multi-scale modeling to investigate the mechanisms by which flow affects the dynamics of all individual cells in growing biofilms. Our experiments and cell-based simulations reveal three quantitatively different growth phases in strong external flow, and the transitions between them. In the initial stages of biofilm development, flow induces a downstream gradient in cell orientation, causing asymmetrical droplet-like biofilm shapes. In the later developmental stages, when the majority of cells are sheltered from the flow by the surrounding extracellular matrix, buckling-induced cell verticalization in the biofilm core restores radially symmetric biofilm growth, in agreement with predictions of a 3D continuum model.

scholarly journals Amylases: Biofilm Inducer or Biofilm Inhibitor?

2021 ◽  
Vol 11 ◽  
Author(s):  
Dibyajit Lahiri ◽  
Moupriya Nag ◽  
Ritwik Banerjee ◽  
Dipro Mukherjee ◽  
Sayantani Garai ◽  
...  
Keyword(s):  
Antimicrobial Agent ◽  
Extracellular Polymeric Substances ◽  
Binding Protein ◽  
The Other ◽  
Natural Environments ◽  
Salivary Amylase ◽  
Functional Characteristics ◽  
Microbial Cells ◽  
Abiotic Surfaces ◽  
Biofilm Inhibitor

Biofilm is a syntrophic association of sessile groups of microbial cells that adhere to biotic and abiotic surfaces with the help of pili and extracellular polymeric substances (EPS). EPSs also prevent penetration of antimicrobials/antibiotics into the sessile groups of cells. Hence, methods and agents to avoid or remove biofilms are urgently needed. Enzymes play important roles in the removal of biofilm in natural environments and may be promising agents for this purpose. As the major component of the EPS is polysaccharide, amylase has inhibited EPS by preventing the adherence of the microbial cells, thus making amylase a suitable antimicrobial agent. On the other hand, salivary amylase binds to amylase-binding protein of plaque-forming Streptococci and initiates the formation of biofilm. This review investigates the contradictory actions and microbe-associated genes of amylases, with emphasis on their structural and functional characteristics.

scholarly journals Abstracts of an international conference “Biofilms II: Attachment and detachment in pure and mixed cultures”, held at the Leipziger Kubus UFZ Centre for Environmental Research, Leipzig, Germany, from 23 March to 24 March 2006

Biofilms ◽  
2005 ◽  
Vol 2 (4) ◽  
pp. 245-273
Keyword(s):  
Escherichia Coli ◽  
Biofilm Formation ◽  
Extracellular Polymeric Substances ◽  
Three Dimensional ◽  
Conjugative Plasmid ◽  
Environmental Research ◽  
Biofilm Growth ◽  
Biofilm Detachment ◽  
Biofilm Development

The effect of growth and detachment on formation of large-scale biofilm structureBiofilm cohesive energy density determination using a novel atomic force microscopy methodologyFluorescence correlation spectroscopy under two-photon excitation for the study of diffusion and reactivity of bacteriophage inside bacterial biofilmsBiothermodynamic characterization and dynamic analysis of biofilms using calorimetryBiomimetic antifouling coatings for sensor surfaces for water monitoring: performance control in defined biofilm cultures and under real environmental conditionsThe contribution of rpos to formation of Escherichia coli biofilmsSynergistic effects in mixed Escherichia coli biofilms: conjugative plasmid transfer drives biofilm expansionThe universal stress protein PA3309 in Pseudomonas aeruginosa is induced in biofilmsExtracellular polymeric substances from biofilms on membranes in waste-water treatment plantsBiofilm-to-planktonic cell yield: a strategy for proliferationPhysiological and phylogenetic characterization of the dispersed and loosely attached fraction of activated sludge flocsTowards a deterministic model of biofilm detachment: an experimental studyEffect of backwash on the characteristics of biofilm in a biological activated filter reactor using elemental sulfur particlesProcess performance and biomass properties in membrane-aerated bioreactorsBioaugmentation via conjugation in biofilms treating 3-chloroaniline: effects of selective pressureEffect of phosphorus on biofilm growth in a completely mixed biofilm reactorImpacts of biofilm development on reactive transport in porous media under variable flow regimensInfluence of biofilms on colloid mobility in the subsurfaceBiofilms in amendable in situ microcosms indicate relevant electron acceptor processes at a BTEX-contaminated aquiferFunctional biodiversity of complex biofilms grown on polychlorinated biphenyl oilIdentification and characterization of biofilm formation phenotypes of several clinically relevant Streptococcus pyogenes serotype strainsSelected probiotic bacteria disrupt biofilm development of vancomycin-resistant Enterococcus faeciumComparison of the extracellular polymeric substances of Candida albicans and Candida dubliniensis biofilmsInfluence of quorum-sensing regulated production of an antimicrobial component by Serratia plymuthica on establishment of dual species biofilms with Escherichia coliBiofilm formation by the thermophilic and cellulolytic actinomycete Thermobifida fuscaBiomonitoring of bacterial contamination on different surfaces of food-processing machinesRole of the flagella during the adhesion of Listeria monocytogenes EGD-e to inert surfaces after cultivation at different pHs and temperaturesAdhesion of Saccharomyces cerevisiae to stainless steel: influence of surface propertiesInvestigating the mechanical strength of biofilms with fluid dynamic gaugingThree-dimensional biofilm model with individual cells and continuum extracellular polymeric substances matrixA three-dimensional computer model analysis of four hypothetical biofilm detachment mechanismsModelling biofilm growth, detachment and fluid flow in a cross-section of tube reactorsBiofilm games

scholarly journals Regulation of Biofilm Aging and Dispersal inBacillus subtilisby the Alternative Sigma Factor SigB

2018 ◽  
Vol 201 (2) ◽  
Author(s):  
M. Bartolini ◽  
S. Cogliati ◽  
D. Vileta ◽  
C. Bauman ◽  
L. Rateni ◽  
...  
Keyword(s):  
Bacillus Subtilis ◽  
Bacterial Survival ◽  
Medical Systems ◽  
Biofilm Growth ◽  
Waste Products ◽  
Content Type ◽  
Regulatory Cascade ◽  
Regulatory Circuit ◽  
Metabolic Conditions ◽  
Biofilm Development

ABSTRACTBacterial biofilms are important in natural settings, biotechnology, and medicine. However, regulation of biofilm development and its persistence in different niches is complex and only partially understood. One key step during the biofilm life cycle is dispersal, when motile cells abandon the mature biofilm to spread out and colonize new niches. Here, we show that in the model bacteriumBacillus subtilisthe general stress transcription factor SigB is essential for halting detrimental overgrowth of mature biofilm and for triggering dispersal when nutrients become limited. Specifically, SigB-deficient biofilms were larger than wild-type biofilms but exhibited accelerated cell death, significantly greater sensitivity to different stresses, and reduced dispersal. Interestingly, the signal detected by SigB to limit biofilm growth was transduced through the RsbP-dependent metabolic arm of the SigB regulatory cascade, which in turn positively controlled expression of SinR, the master regulator of biofilm formation and cell motility. This novel SigB-SinR regulatory circuit might be important in controlling the fitness of biofilms (either beneficial or harmful) in diverse environments.IMPORTANCEBiofilms are crucial for bacterial survival, adaptation, and dissemination in natural, industrial, and medical systems. Sessile cells embedded in the self-produced extracellular matrix of the biofilm benefit from a division of labor and are protected from environmental insults. However, as the biofilm ages, cells become stressed because of overcrowding, starvation, and accumulation of waste products. How does the sessile biofilm community sense and respond to stressful conditions? Here, we show that inBacillus subtilis, the transcription factors SigB and SinR control whether cells remain in or leave a biofilm when metabolic conditions become unfavorable. This novel SigB-SinR regulatory circuit might be important for controlling the fitness of biofilms (either beneficial or harmful) in diverse environments.

scholarly journals Optical Sensing of Microbial Life on Surfaces

2015 ◽  
Vol 82 (5) ◽  
pp. 1362-1371 ◽  
Author(s):  
M. Fischer ◽  
G. J. Triggs ◽  
T. F. Krauss
Keyword(s):  
Basic Research ◽  
High Sensitivity ◽  
Natural Environments ◽  
Label Free ◽  
Biofilm Growth ◽  
Microbial Cells ◽  
Industrial Facilities ◽  
Label Free Detection ◽  
Sensitivity And Selectivity ◽  
The Many

ABSTRACTThe label-free detection of microbial cells attached to a surface is an active field of research. The field is driven by the need to understand and control the growth of biofilms in a number of applications, including basic research in natural environments, industrial facilities, and clinical devices, to name a few. Despite significant progress in the ability to monitor the growth of biofilms and related living cells, the sensitivity and selectivity of such sensors are still a challenge. We believe that among the many different technologies available for monitoring biofilm growth, optical techniques are the most promising, as they afford direct imaging and offer high sensitivity and specificity. Furthermore, as each technique offers different insights into the biofilm growth mechanism, our analysis allows us to provide an overview of the biological processes at play. In addition, we use a set of key parameters to compare state-of-the-art techniques in the field, including a critical assessment of each method, to identify the most promising types of sensors. We highlight the challenges that need to be overcome to improve the characteristics of current biofilm sensor technologies and indicate where further developments are required. In addition, we provide guidelines for selecting a suitable sensor for detecting microbial cells on a surface.

Beneficial biofilms: A mini-review of strategies to enhance biofilm formation for biotechnological applications

2021 ◽  
Author(s):  
Mayur Mukhi ◽  
A. S. Vishwanathan
Keyword(s):  
Biofilm Formation ◽  
Environmental Remediation ◽  
Extracellular Polymeric Substances ◽  
External Environment ◽  
Bacterial Cells ◽  
Biotechnological Applications ◽  
Biofilm Growth ◽  
Research Attention ◽  
Signaling Systems ◽  
Biofilm Development

The capacity of bacteria to form biofilms is an important trait for their survival and persistence. Biofilms occur naturally in soil and aquatic environments, are associated with animals ranging from insects to humans and are also found in built environments. They are typically encountered as a challenge in healthcare, food industry, and water supply ecosystems. In contrast, they are known to play a key role in the industrial production of commercially valuable products, environmental remediation processes, and in microbe-catalysed electrochemical systems for energy and resource recovery from wastewater. While there are many recent articles on biofilm control and removal, review articles on promoting biofilm growth for biotechnological applications are unavailable. Biofilm formation is a tightly regulated response to perturbations in the external environment. The multi-stage process, mediated by an assortment of proteins and signaling systems, involves the attachment of bacterial cells to a surface followed by their aggregation in a matrix of extracellular polymeric substances. Biofilms can be promoted by altering the external environment in a controlled manner, supplying molecules that trigger the aggregation of cells and engineering genes associated with biofilm development. This mini-review synthesizes findings from studies that have described such strategies and highlights areas needing research attention.

Bifunctional Composites for Biofilms Modulation on Cervical Restorations

2021 ◽  
pp. 002203452110181
Author(s):  
A.A. Balhaddad ◽  
I.M. Garcia ◽  
L. Mokeem ◽  
M.S. Ibrahim ◽  
F.M. Collares ◽  
...  
Keyword(s):  
Free Energy ◽  
Surface Free Energy ◽  
Contact Angles ◽  
Bacterial Biofilm ◽  
Dental Composite ◽  
Log P ◽  
Rrna Gene ◽  
Cervical Lesions ◽  
Biofilm Growth ◽  
Biofilm Development

Cervical composites treating root carious and noncarious cervical lesions usually extend subgingivally. The subgingival margins of composites present poor plaque control, enhanced biofilm accumulation, and cause gingival irritation. A potential material to restore such lesions should combine agents that interfere with bacterial biofilm development and respond to acidic conditions. Here, we explore the use of new bioresponsive bifunctional dental composites against mature microcosm biofilms derived from subgingival plaque samples. The designed formulations contain 2 bioactive agents: dimethylaminohexadecyl methacrylate (DMAHDM) at 3 to 5 wt.% and 20 wt.% nanosized amorphous calcium phosphate (NACP) in a base resin. Composites with no DMAHDM and NACP were used as controls. The newly formulated 5% DMAHDM–20% NACP composite was analyzed by micro-Raman spectroscopy and transmission electron microscopy. The wettability and surface-free energy were also assessed. The inhibitory effect on the in vitro biofilm growth and the 16S rRNA gene sequencing of survival bacterial colonies derived from the composites were analyzed. Whole-biofilm metabolic activity, polysaccharide production, and live/dead images of the biofilm grown over the composites complement the microbiological assays. Overall, the designed formulations had higher contact angles with water and lower surface-free energy compared to the commercial control. The DMAHDM-NACP composites significantly inhibited the growth of total microorganisms, Porphyromonas gingivalis, Prevotella intermedia/nigrescens, Aggregatibacter actinomycetemcomitans, and Fusobacterium nucleatum by 3 to 5-log ( P < 0.001). For the colony isolates from control composites, the composition was typically dominated by the genera Veillonella, Fusobacterium, Streptococcus, Eikenella, and Leptotrichia, while Fusobacterium and Veillonella dominated the 5% DMAHDM–20% NACP composites. The DMAHDM-NACP composites contributed to over 80% of reduction in metabolic and polysaccharide activity. The suppression effect on plaque biofilms suggested that DMAHDM-NACP composites might be used as a bioactive material for cervical restorations. These results may propose an exciting path to prevent biofilm growth and improve dental composite restorations’ life span.

scholarly journals Influence of biopolymers on the rheological properties of seafloor sediments and the runout behavior of submarine debris flows

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jun Kameda ◽  
Hamada Yohei
Keyword(s):  
Rheological Properties ◽  
Debris Flows ◽  
Extracellular Polymeric Substances ◽  
Flow Behavior ◽  
Mass Movement ◽  
Rheological Parameters ◽  
Natural Environments ◽  
Natural Systems ◽  
Chemical Conditions ◽  
Seafloor Sediments

AbstractSubmarine debris flows are mass movement processes on the seafloor, and are geohazards for seafloor infrastructure such as pipelines, communication cables, and submarine structures. Understanding the generation and run-out behavior of submarine debris flows is thus critical for assessing the risk of such geohazards. The rheological properties of seafloor sediments are governed by factors including sediment composition, grain size, water content, and physico-chemical conditions. In addition, extracellular polymeric substances (EPS) generated by microorganisms can affect rheological properties in natural systems. Here we show that a small quantity of EPS (~ 0.1 wt%) can potentially increase slope stability and decrease the mobility of submarine debris flows by increasing the internal cohesion of seafloor sediment. Our experiments demonstrated that the flow behavior of sediment suspensions mixed with an analogue material of EPS (xanthan gum) can be described by a Herschel–Bulkley model, with the rheological parameters being modified progressively, but not monotonously, with increasing EPS content. Numerical modeling of debris flows demonstrated that the run-out distance markedly decreases if even 0.1 wt% of EPS is added. The addition of EPS can also enhance the resistivity of sediment to fluidization triggered by cyclic loading, by means of formation of an EPS network that binds sediment particles. These findings suggest that the presence of EPS in natural environments reduces the likelihood of submarine geohazards.

scholarly journals Bacterial Cellulose from Food to Biomedical Products

2020 ◽  
Vol 14 (1) ◽  
pp. 124-133
Author(s):  
Supajit Sraphet ◽  
Bagher Javadi
Keyword(s):  
Bacterial Cellulose ◽  
Extracellular Polymeric Substances ◽  
Control Strategies ◽  
Low Cost ◽  
Cell Communication ◽  
Future Application ◽  
Membrane Structures ◽  
Food Ingredient ◽  
Expression Of Genes ◽  
Biofilm Development

Cellulose production of aerobic bacteria with its very unique physiochemical properties attracted many researchers. The biosynthetic of Bacterial Cellulose (BC) was produced by low-cost media recently. BC has been used as biomaterials and food ingredient these days. Moreover, the capacity of BC composite gives the numerous application opportunities in other fields. Bacterial Cellulose (BC) development is differentiated from suspension planktonic culture by their Extracellular Polymeric Substances (EPS), down-regulation of growth rate and up-down the expression of genes. The attachment of microorganisms is highly dependent on their cell membrane structures and growth medium. This is a very complicated phenomenon that optimal conditions defined the specific architecture. This architecture is made of microbial cells and EPS. Cell growth and cell communication mechanisms effect biofilm development and detachment. Understandings of development and architecture mechanisms and control strategies have a great impact on the management of BC formation with beneficial microorganisms. This mini-review paper presents the overview of outstanding findings from isolating and characterizing the diversity of bacteria to BC's future application, from food to biosensor products. The review would help future researchers in the sustainable production of BC, applications advantages and opportunities in food industry, biomaterial and biomedicine.

Sign in / Sign up

Export Citation Format

Share Document