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

Zhang, W.; Dai, Weiran; Tsai, S. M.; Zehnder, Steven; Sarntinoranont, Malisa; Angelini, Thomas E.

doi:10.1039/c5sm00148j

Cited by 13 publications

(22 citation statements)

References 25 publications

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“…In commonly used laboratory media that promote colony biofilm development of B. subtilis , cells attach to the agar surface and produce complex robust structures within three to four days. The biofilm matrix components such as EPS, TasA, and BslA play an essential role in colony wrinkleality as well as influence the indentation on the agar surface [ 44 , 45 ]. Interestingly, in the absence of Ca 2+ , peripheral cells in the complex colonies expand radially after four days, likely due to nutrient depletion.…”

Section: Discussionmentioning

confidence: 99%

Presence of Calcium Lowers the Expansion of Bacillus subtilis Colony Biofilms

et al. 2017

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Robust colony formation by Bacillus subtilis is recognized as one of the sessile, multicellular lifestyles of this bacterium. Numerous pathways and genes are responsible for the architecturally complex colony structure development. Cells in the biofilm colony secrete extracellular polysaccharides (EPS) and protein components (TasA and the hydrophobin BslA) that hold them together and provide a protective hydrophobic shield. Cells also secrete surfactin with antimicrobial as well as surface tension reducing properties that aid cells to colonize the solid surface. Depending on the environmental conditions, these secreted components of the colony biofilm can also promote the flagellum-independent surface spreading of B. subtilis, called sliding. In this study, we emphasize the influence of Ca2+ in the medium on colony expansion of B. subtilis. Interestingly, the availability of Ca2+ has no major impact on the induction of complex colony morphology. However, in the absence of this divalent ion, peripheral cells of the colony expand radially at later stages of development, causing colony size to increase. We demonstrate that the secreted extracellular compounds, EPS, BslA, and surfactin facilitate colony expansion after biofilm maturation. We propose that Ca2+ hinders biofilm colony expansion by modifying the amphiphilic properties of surfactin.

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Section: Discussionmentioning

confidence: 99%

Presence of Calcium Lowers the Expansion of Bacillus subtilis Colony Biofilms

et al. 2017

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“…These biofilms are surfaces with a high rate of structural organization associated with bacterial colonies held together by a polymer secreted by their cells, which is called extracellular polymeric substance (EPS) (Watnick andKolter, 2000, Donlan, 2002;Zhang et al, 2015). Among many strategies used for the study of biofilms, the one that is more highlighted is the use of the Atomic Force Microscopy (AFM), which allows measurement of the interaction forces between cells or cell-cell interactions (Dufrêne, 2015).…”

Section: Introductionmentioning

confidence: 99%

Study of kefir biofilm associated with hydroethanolic extract of Euterpe oleracea Mart. (aai)

Oliveira¹,

Maciel²,

Florentino³

et al. 2017

Afr. J. Microbiol. Res.

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Kefir is a microbial complex capable of producing biofilms. This study aims to obtain biofilms associated with hydroethanolic extract of Euterpe oleracea Mart. (BEHEEo) as fixing method of recovery anthocyanins in kefir biofilm. Thus, BEHEEo formation kinetics was made at different concentrations of aqueous extract of E. oleracea, of kefir grains (KG) and of brown sugar (BS). Thereafter, macro and microelements of BEHEEo were determined; the rheological and structural characteristics were analyzed using atomic force microscopy (AFM), and anthocyanins dosage in BEHEEo was obtained. The best concentration of BS to form BEHEEo was 40 g/l with 100 ml of EHEEo (12.62±0.16 g), as well as a release of the BEHEEo anthocyanins occurring after 5 min (4.3±0.6 mg/100 g) with maximum peak at 60 min (20.8±0.3). The concentration of calcium iron and magnesium was 0.089, 0.1740 and 0.1808 mg/kg, respectively, indicating the concentration of Zn2+ which was 0.533 mg/kg. The AFM analysis revealed differences in the peaks of roughness depending on the concentration of kefir grains, with presence of Lactobacillus and yeast. The concentration of anthocyanins in BEHEEo two years after the incorporation was 26 mg/100 g. Therefore, it is suggested that the BEHEEo incorporating EHEEo anthocyanins has potential for therapeutic applications in several pathologies necessary for antioxidative processes.Key words: Biofilms, kefir, açaí, Euterpe oleracea Mart., anthocyanins, atomic force microscopy (AFM). INTRODUCTIONKefir is a beverage produced by fermenting substrates such as milk or sugar water by kefir grains (Rodrigues et al., 2005;Laureys and De Vuyst, 2014). The growth and the function of bacteria inside a population are crucial for their survival (Davey and O'toole, 2000). In kefir, there is a predominance of Lactobacillus which has high catabolic capacity and is complemented by yeast with high biosynthetic capacity.When growing kefir in water for more than twenty days, there is the formation of biofilms with therapeutic properties against pathogenic organisms. These biofilms are surfaces with a high rate of structural organization associated with bacterial colonies held together by a polymer secreted by their cells, which is called extracellular polymeric substance (EPS) (Watnick and Kolter, 2000, Donlan, 2002;Zhang et al., 2015). Among many strategies used for the study of biofilms, the one that is more highlighted is the use of the Atomic Force Microscopy (AFM), which allows measurement of the interaction forces between cells or cell-cell interactions (Dufrêne, 2015).One of the substances that have been intensified in recent years are the anthocyanins, due to their protective and healing properties. Anthocyanins have an important role in physiological functions related to human health (Lee et al., 2013). The antioxidant effect of anthocyanins have been known and proven fact. The action mechanism of the anthocyanin is inhibiting the free radicals that promote oxidation. The antioxidant agents capable of binding to the free radicals ...

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“…These studies comprise work on biofilm elasticity (16,17,28,29), biofilm erosion stability (30), and adhesion properties (31-33), as well as theoretical investigations of mechanical biofilm characteristics (34,35). Biofilm formation by the bacterium Bacillus subtilis has been studied intensively (36)(37)(38)(39)(40)(41)(42)(43), but information about the mechanical properties of these biofilm-forming bacteria is just emerging (24,30,44). Hence, a detailed understanding of the mechanical characteristics of bacterial biofilms is urgently needed to fight the growth of bacterial biofilms on medical devices and other industrially used surfaces.…”

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confidence: 99%

Direct Comparison of Physical Properties of Bacillus subtilis NCIB 3610 and B-1 Biofilms

Kesel

Grumbein

Gümperlein

et al. 2016

Appl Environ Microbiol

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cMany bacteria form surface-attached communities known as biofilms. Due to the extreme resistance of these bacterial biofilms to antibiotics and mechanical stresses, biofilms are of growing interest not only in microbiology but also in medicine and industry. Previous studies have determined the extracellular polymeric substances present in the matrix of biofilms formed by Bacillus subtilis NCIB 3610. However, studies on the physical properties of biofilms formed by this strain are just emerging. In particular, quantitative data on the contributions of biofilm matrix biopolymers to these physical properties are lacking. Here, we quantitatively investigated three physical properties of B. subtilis NCIB 3610 biofilms: the surface roughness and stiffness and the bulk viscoelasticity of these biofilms. We show how specific biomolecules constituting the biofilm matrix formed by this strain contribute to those biofilm properties. In particular, we demonstrate that the surface roughness and surface elasticity of 1-day-old NCIB 3610 biofilms are strongly affected by the surface layer protein BslA. For a second strain, B. subtilis B-1, which forms biofilms containing mainly ␥-polyglutamate, we found significantly different physical biofilm properties that are also differently affected by the commonly used antibacterial agent ethanol. We show that B-1 biofilms are protected from ethanol-induced changes in the biofilm's stiffness and that this protective effect can be transferred to NCIB 3610 biofilms by the sole addition of ␥-polyglutamate to growing NCIB 3610 biofilms. Together, our results demonstrate the importance of specific biofilm matrix components for the distinct physical properties of B. subtilis biofilms. Bacteria embed themselves with secreted biopolymers (1-3), building a community that is referred to as a biofilm. Such biofilms can be formed by a variety of Gram-positive as well as Gram-negative bacteria (4). The composition of the biofilm matrix is dependent on the biofilm-forming bacterium and environmental conditions such as shear forces experienced, temperature, and nutrient availability (5); the matrix can consist of different extracellular polymeric substances (EPSs), such as polysaccharides, proteins, lipids, and nucleic acids (6). Biofilms can grow on various surfaces (7-9). While Bacillus subtilis biofilms are formed on solid nutrient surfaces or at liquid-air interfaces (10, 11), other bacteria can produce biofilms on surfaces under water-saturated conditions (in liquid) (12). Due to their high mechanical stability (13,14) and their resistance to antibiotic or chemical treatment (15-18), such biofilms present significant problems in both industry and health care (19)(20)(21)(22). Although the compositions of many biofilm matrices are known, the biomolecular reason for the outstanding resistance of bacterial biofilms is not well understood. Only a few studies have investigated the influence of specific matrix components on the mechanical properties of biofilms (23, 24). The majority of recent studies...

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

Cited by 13 publications

References 25 publications

Presence of Calcium Lowers the Expansion of Bacillus subtilis Colony Biofilms

Presence of Calcium Lowers the Expansion of Bacillus subtilis Colony Biofilms

Study of kefir biofilm associated with hydroethanolic extract of Euterpe oleracea Mart. (aai)

Direct Comparison of Physical Properties of Bacillus subtilis NCIB 3610 and B-1 Biofilms

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