Archaeal biofilms: widespread and complex

Biofilms or multicellular structures become accepted as the dominant microbial lifestyle in Nature, but in the past they were only studied extensively in bacteria. Investigations on archaeal monospecies cultures have shown that many archaeal species are able to adhere on biotic and abiotic surfaces and form complex biofilm structures. Biofilm-forming archaea were identified in a broad range of extreme and moderate environments. Natural biofilms observed are mostly mixed communities composed of archaeal and bacterial species of various abundances. The physiological functions of the archaea identified in such mixed communities suggest a significant impact on the biochemical cycles maintaining the flow and recycling of the nutrients on earth. Therefore it is of high interest to investigate the characteristics and mechanisms underlying the archaeal biofilm formation. In the present review, I summarize and discuss the present investigations of biofilm-forming archaeal species, i.e. their diverse biofilm architectures in monospecies or mixed communities, the identified EPSs (extracellular polymeric substances), archaeal structures mediating surface adhesion or cell–cell connections, and the response to physical and chemical stressors implying that archaeal biofilm formation is an adaptive reaction to changing environmental conditions. A first insight into the molecular differentiation of cells within archaeal biofilms is given.

Download Full-text

Mechanistic insight into the conserved allosteric regulation of periplasmic proteolysis by the signaling molecule cyclic-di-GMP

eLife ◽

10.7554/elife.03650 ◽

2014 ◽

Vol 3 ◽

Cited By ~ 28

Author(s):

Debashree Chatterjee ◽

Richard B Cooley ◽

Chelsea D Boyd ◽

Ryan A Mehl ◽

George A O'Toole ◽

...

Keyword(s):

Biofilm Formation ◽

Bacterial Species ◽

Adaptation Strategy ◽

Bacterial Biofilm ◽

Surface Adhesion ◽

Receptor System ◽

Changing Environments ◽

Mechanistic Insight ◽

A Cell ◽

Insight Into

Stable surface adhesion of cells is one of the early pivotal steps in bacterial biofilm formation, a prevalent adaptation strategy in response to changing environments. In Pseudomonas fluorescens, this process is regulated by the Lap system and the second messenger cyclic-di-GMP. High cytoplasmic levels of cyclic-di-GMP activate the transmembrane receptor LapD that in turn recruits the periplasmic protease LapG, preventing it from cleaving a cell surface-bound adhesin, thereby promoting cell adhesion. In this study, we elucidate the molecular basis of LapG regulation by LapD and reveal a remarkably sensitive switching mechanism that is controlled by LapD's HAMP domain. LapD appears to act as a coincidence detector, whereby a weak interaction of LapG with LapD transmits a transient outside-in signal that is reinforced only when cyclic-di-GMP levels increase. Given the conservation of key elements of this receptor system in many bacterial species, the results are broadly relevant for cyclic-di-GMP- and HAMP domain-regulated transmembrane signaling.

Download Full-text

Antibiotics Application Strategies to Control Biofilm Formation in Pathogenic Bacteria

Current Pharmaceutical Biotechnology ◽

10.2174/1389201020666191112155905 ◽

2020 ◽

Vol 21 (4) ◽

pp. 270-286 ◽

Cited By ~ 2

Author(s):

Fazlurrahman Khan ◽

Dung T.N. Pham ◽

Sandra F. Oloketuyi ◽

Young-Mog Kim

Keyword(s):

Biofilm Formation ◽

Pathogenic Bacteria ◽

Extracellular Polymeric Substances ◽

Quorum Quenching ◽

Resistance Mechanisms ◽

Bacterial Biofilm ◽

Bacterial Cells ◽

High Concentration ◽

Biofilm Inhibition ◽

Abiotic Surfaces

Background: The establishment of a biofilm by most pathogenic bacteria has been known as one of the resistance mechanisms against antibiotics. A biofilm is a structural component where the bacterial community adheres to the biotic or abiotic surfaces by the help of Extracellular Polymeric Substances (EPS) produced by bacterial cells. The biofilm matrix possesses the ability to resist several adverse environmental factors, including the effect of antibiotics. Therefore, the resistance of bacterial biofilm-forming cells could be increased up to 1000 times than the planktonic cells, hence requiring a significantly high concentration of antibiotics for treatment. Methods: Up to the present, several methodologies employing antibiotics as an anti-biofilm, antivirulence or quorum quenching agent have been developed for biofilm inhibition and eradication of a pre-formed mature biofilm. Results: Among the anti-biofilm strategies being tested, the sub-minimal inhibitory concentration of several antibiotics either alone or in combination has been shown to inhibit biofilm formation and down-regulate the production of virulence factors. The combinatorial strategies include (1) combination of multiple antibiotics, (2) combination of antibiotics with non-antibiotic agents and (3) loading of antibiotics onto a carrier. Conclusion: The present review paper describes the role of several antibiotics as biofilm inhibitors and also the alternative strategies adopted for applications in eradicating and inhibiting the formation of biofilm by pathogenic bacteria.

Download Full-text

Agrobacterium tumefaciens ExoR represses succinoglycan biosynthesis and is required for biofilm formation and motility

Microbiology ◽

10.1099/mic.0.039032-0 ◽

2010 ◽

Vol 156 (9) ◽

pp. 2670-2681 ◽

Cited By ~ 42

Author(s):

Amelia D. Tomlinson ◽

Bronwyn Ramey-Hartung ◽

Travis W. Day ◽

Peter M. Merritt ◽

Clay Fuqua

Keyword(s):

Agrobacterium Tumefaciens ◽

Biofilm Formation ◽

Sinorhizobium Meliloti ◽

Plant Tissues ◽

Flagellar Motility ◽

Regulatory Pathway ◽

Flow Conditions ◽

Two Component System ◽

Form Complex ◽

Abiotic Surfaces

The ubiquitous plant pathogen Agrobacterium tumefaciens attaches efficiently to plant tissues and abiotic surfaces and can form complex biofilms. A genetic screen for mutants unable to form biofilms on PVC identified disruptions in a homologue of the exoR gene. ExoR is a predicted periplasmic protein, originally identified in Sinorhizobium meliloti, but widely conserved among alphaproteobacteria. Disruptions in the A. tumefaciens exoR gene result in severely compromised attachment to abiotic surfaces under static and flow conditions, and to plant tissues. These mutants are hypermucoid due to elevated production of the exopolysaccharide succinoglycan, via derepression of the exo genes that direct succinoglycan synthesis. In addition, exoR mutants have lost flagellar motility, do not synthesize detectable flagellin and are diminished in flagellar gene expression. The attachment deficiency is, however, complex and not solely attributable to succinoglycan overproduction or motility disruption. A. tumefaciens ExoR can function independently of the ChvG–ChvI two component system, implicated in ExoR-dependent regulation in S. meliloti. Mutations that suppress the exoR motility defect suggest a branched regulatory pathway controlling succinoglycan synthesis, motility and biofilm formation.

Download Full-text

Lessons in Fundamental Mechanisms and Diverse Adaptations from the 2015 Bacterial Locomotion and Signal Transduction Meeting

Journal of Bacteriology ◽

10.1128/jb.00384-15 ◽

2015 ◽

Vol 197 (19) ◽

pp. 3028-3040 ◽

Cited By ~ 3

Author(s):

Birgit M. Prüβ ◽

Jun Liu ◽

Penelope I. Higgs ◽

Lynmarie K. Thompson

Keyword(s):

Signal Transduction ◽

Biofilm Formation ◽

Cell Biology ◽

Bacterial Species ◽

Interacting Proteins ◽

Mathematical Methods ◽

Detailed Understanding ◽

Rapid Changes ◽

Functional Mechanisms ◽

Insight Into

In response to rapid changes in their environment, bacteria control a number of processes, including motility, cell division, biofilm formation, and virulence. Research presented in January 2015 at the biennial Bacterial Locomotion and Signal Transduction (BLAST) meeting in Tucson, AZ, illustrates the elegant complexity of the nanoarrays, nanomachines, and networks of interacting proteins that mediate such processes. Studies employing an array of biophysical, genetic, cell biology, and mathematical methods are providing an increasingly detailed understanding of the mechanisms of these systems within well-studied bacteria. Furthermore, comparisons of these processes in diverse bacterial species are providing insight into novel regulatory and functional mechanisms. This review summarizes research presented at the BLAST meeting on these fundamental mechanisms and diverse adaptations, including findings of importance for applications involving bacteria of medical or agricultural relevance.

Download Full-text

Bacteriophages as an Alternative Strategy for Fighting Biofilm Development

Polish Journal of Microbiology ◽

10.33073/pjm-2014-019 ◽

2014 ◽

Vol 63 (2) ◽

pp. 137-145 ◽

Cited By ~ 56

Author(s):

SYLWIA PARASION ◽

MAGDALENA KWIATEK ◽

ROMUALD GRYKO ◽

LIDIA MIZAK ◽

ANNA MALM

Keyword(s):

Biofilm Formation ◽

Extracellular Polymeric Substances ◽

Bacterial Resistance ◽

Bacterial Species ◽

Experimental Studies ◽

Alternative Methods ◽

Resistant Bacteria ◽

Bacterial Cells ◽

Coagulase Negative Staphylococci ◽

Biofilm Development

The ability of microbes to form biofilms is an important element of their pathogenicity, and biofilm formation is a serious challenge for today's medicine. Fighting the clinical complications associated with biofilm formation is very difficult and linked to a high risk of failure, especially in a time of increasing bacterial resistance to antibiotics. Bacterial species most commonly isolated from biofilms include coagulase-negative staphylococci, Staphylococcus aureus, Enterococcus faecalis, Enterococcus faecium, Escherichia coli, Proteus mirabilis, Klebsiella pneumoniae, Pseudomonas aeruginosa and Acinetobacter spp. The frequent failure of antibiotic therapy led researchers to look for alternative methods and experiment with the use of antibacterial factors with a mechanism of action different from that of antibiotics. Experimental studies with bacteriophages and mixtures thereof, expressing lytic properties against numerous biofilm-forming bacterial species showed that bacteriophages may both prevent biofilm formation and contribute to eradication of biofilm bacteria. A specific role is played here by phage depolymerases, which facilitate the degradation of extracellular polymeric substances (EPS) and thus the permeation of bacteriophages into deeper biofilm layers and lysis of the susceptible bacterial cells. Much hope is placed in genetic modifications of bacteriophages that would allow the equipping bacteriophages with the function of depolymerase synthesis. The use of phage cocktails prevents the development of phage-resistant bacteria.

Download Full-text

A brief exploration of EPS composition in biofilms of Staphylococcus spp ATCC reference strains

10.5194/biofilms9-129 ◽

2020 ◽

Author(s):

Cristina D. Cruz ◽

Rebekah C. Hewitt ◽

Päivi Tammela

Keyword(s):

Biofilm Formation ◽

Extracellular Polymeric Substances ◽

Bacterial Biofilm ◽

Biofilm Growth ◽

Time Points ◽

Microtiter Plates ◽

The Matrix ◽

Sulfuric Acid Method ◽

Staphylococcus Spp ◽

Physical And Chemical

Antibiotic resistance is expected to cause 10 million deaths per year worldwide by 2050. One of the mechanisms for the resilient nature of bacteria toward antibiotics is through the formation of biofilm. Bacterial biofilms are sessile communities of microorganisms, which exist in a matrix of proteins, carbohydrates, eDNA and other various components &#8211; collectively known as extracellular polymeric substances. Biofilms slow the penetration of drugs, and also contribute to the development of a resistant phenotype known as persisters. Thus, understanding biofilm composition might contribute to the development of anti-biofilm strategies. The aim of this study was to explore biofilm formed by five Staphylococcus spp ATCC strains, commonly used in research as references: S. aureus 25923, S. aureus 29213, S. aureus 43300 (methicillin-resistant), S. aureus 6538 and S. epidermidis 12228. Biofilm mass and its components were analysed after 24h and 72h of biofilm growth. Bacterial biofilm was prepared in 96-well microtiter plates, in Trypticase Soy Broth supplemented with 1% glucose. After incubation at 37&#176;C, absorbance measurements and crystal violet staining were performed and the specific biofilm formation determined for each strain. Extracellular polymeric substances were extracted using a combination of physical and chemical methods; including centrifugation, vortexing and the use of 1.5M NaCl. In these assays, biofilms were grown in polystyrene tubes containing 10 ml of same media mentioned above. The concentration of protein, carbohydrate and eDNA was determined using the Bicinchoninic acid assay, phenol-sulfuric acid method and DNeasy&#174; Blood and Tissue Kit, respectively, followed by spectroscopy. Our data demonstrated heterogeneity between the biofilm-forming capabilities and EPS components within staphylococcal strains and species. Strains 25923 and 6538 had the highest value for biofilm formation at both time points. Interestingly, strain 43300 was the only one to show a significant increase in biofilm after 72h. Contradictory to previous findings, S. epidermidis 12228 was found to be a good biofilm producer. At both time points studied, strains demonstrated considerably higher concentrations of protein (varying from 172 &#181;g/mL &#8211; 345 &#181;g/mL) and carbohydrate (56 &#181;g/mL - 372&#181;g/mL) in EPS compared to eDNA (2.74 &#181;g/mL &#8211; 8.12 &#181;g/mL). On average, strains 43300 and 12228 had the highest concentration of protein, and the latter also had the highest carbohydrate and eDNa amounts at 72h. Strains 25923 and 6538 had a significant decrease in eDNA concentration over time. Based on this brief study, the relative quantities of EPS components investigated is similar to that of other studies with protein being the most plentiful component followed by carbohydrate and then considerably lower amounts of eDNA. Differences in specific biofilm formation did not directly reflect variations observed in abundance of a particular constituent in the matrix of EPS. This study also showed that S. epidermidis 12228, usually classified as a weak or non-biofilm former, was able to grow a relatively substantial biofilm under the conditions tested here.

Download Full-text

Role of a Putative Polysaccharide Locus in Bordetella Biofilm Development

Journal of Bacteriology ◽

10.1128/jb.00953-06 ◽

2006 ◽

Vol 189 (3) ◽

pp. 750-760 ◽

Cited By ~ 82

Author(s):

Gina Parise ◽

Meenu Mishra ◽

Yoshikane Itoh ◽

Tony Romeo ◽

Rajendar Deora

Keyword(s):

Biofilm Formation ◽

Extracellular Polymeric Substances ◽

Glycosyl Hydrolase ◽

Bacterial Biofilm ◽

Abiotic Surfaces ◽

The Stability ◽

Biofilm Development ◽

Complex Architecture ◽

Microscopic Techniques

ABSTRACT Bordetellae are gram-negative bacteria that colonize the respiratory tracts of animals and humans. We and others have recently shown that these bacteria are capable of living as sessile communities known as biofilms on a number of abiotic surfaces. During the biofilm mode of existence, bacteria produce one or more extracellular polymeric substances that function, in part, to hold the cells together and to a surface. There is little information on either the constituents of the biofilm matrix or the genetic basis of biofilm development by Bordetella spp. By utilizing immunoblot assays and by enzymatic hydrolysis using dispersin B (DspB), a glycosyl hydrolase that specifically cleaves the polysaccharide poly-β-1,6-N-acetyl-d-glucosamine (poly-β-1,6-GlcNAc), we provide evidence for the production of poly-β-1,6-GlcNAc by various Bordetella species (Bordetella bronchiseptica, B. pertussis, and B. parapertussis) and its role in their biofilm development. We have investigated the role of a Bordetella locus, here designated bpsABCD, in biofilm formation. The bps (Bordetella polysaccharide) locus is homologous to several bacterial loci that are required for the production of poly-β-1,6-GlcNAc and have been implicated in bacterial biofilm formation. By utilizing multiple microscopic techniques to analyze biofilm formation under both static and hydrodynamic conditions, we demonstrate that the bps locus, although not essential at the initial stages of biofilm formation, contributes to the stability and the maintenance of the complex architecture of Bordetella biofilms.

Download Full-text

Biofilm formation displays intrinsic offensive and defensive features of Bacillus cereus

10.1101/676403 ◽

2019 ◽

Cited By ~ 1

Author(s):

Caro-Astorga Joaquin ◽

Frenzel Elrike ◽

Perkins James Richard ◽

Antonio de Vicente ◽

Juan A.G. Ranea ◽

...

Keyword(s):

Mass Spectrometry ◽

Amino Acids ◽

Cell Wall ◽

Bacillus Cereus ◽

Biofilm Formation ◽

Bacterial Species ◽

Physiological Changes ◽

Effective Strategy ◽

Abiotic Surfaces ◽

The Individual

AbstractBackgroundBiofilm formation is a strategy of many bacterial species to adapt to a variety of stresses and has become a part of infections, contaminations or beneficial interactions. We previously observed that B. cereus ATCC 14579 (CECT148), formed a thick biomass of cells firmly adhered to abiotic surfaces.ResultsIn this study, we combined two techniques, RNAseq and iTRAQ mass spectrometry, to demonstrate the profound physiological changes that permit Bacillus cereus to switch from a floating to a sessile lifestyle, to undergo further maturation of the biofilm, and to differentiate into offensive or defensive populations. The rearrangement of nucleotides, sugars, amino acids and energy metabolism lead to changes promoting reinforcement of the cell wall, activation of ROS detoxification strategies or secondary metabolite production, all oriented to defend biofilm cells from external aggressions. However, floating cells maintain a fermentative metabolic status along with a higher aggressiveness against hosts, evidenced by the production of toxins and other virulent factors.ConclusionsWe show that biofilm-associated cells seem to direct the energy to the individual and global defense against external aggressions and competitors. By contrary, floating cells are more aggressive against hosts. The maintenance of the two distinct subpopulations is an effective strategy to face changeable environmental conditions found in the life cycle of B. cereus.

Download Full-text

Low-concentration Iron Promotes Klebsiella Pneumoniae Biofilm Formation by Suppressing Succinic Acid

10.21203/rs.3.rs-1097604/v1 ◽

2021 ◽

Author(s):

Kexin Liu ◽

Shuang Tan ◽

Weiyuan Ye ◽

Limin Hou ◽

Binghu Fang

Keyword(s):

Electron Microscopy ◽

Klebsiella Pneumoniae ◽

Succinic Acid ◽

Biofilm Formation ◽

Iron Supplementation ◽

Antibacterial Agents ◽

Extracellular Polymeric Substances ◽

Metabolomic Analysis ◽

Planktonic Bacteria ◽

Insight Into

Abstract Background: Klebsiella pneumoniae is widely distributed in water and plays a major role in both human and animal infections. Many K. pneumoniae strains form biofilms on various surfaces, enhancing their pathogenicity and resistance to antibiotics. New ways of inhibiting biofilm formation are needed. Iron is vital to the growth of microorganisms and the formation of biofilms due to its participation in various metabolic processes and its roles as an enzyme and protein cofactor. It is also present in groundwater. The aim of this study was to examine the effects of iron on K. pneumoniae biofilm formation and any associated metabolic changes.Results: Biofilm formation was enhanced to the greatest extent by the presence of 0.16 mM FeCl2, producing a denser structure under electron microscopy. The number of biofilm-forming and planktonic bacteria did not change, but protein and polysaccharide concentrations in the bacterial extracellular polymeric substances (EPS) were significantly increased by iron supplementation. To clarify this mechanism, intracellular metabolomic analysis was carried out, showing that the differential, down-regulated metabolites included succinic acid. Addition of succinic acid counteracted the biofilm-forming effect of iron, with no bactericidal side effects.Conclusion: This study demonstrates the importance of succinic acid and iron in Klebsiella pneumoniae biofilms, and provides insight into the formation of K. pneumoniae biofilms and direction for the development of new antibacterial agents.

Download Full-text

Process Description of an Unconventional Biofilm Formation by Bacterial Cells Autoagglutinating Through Sticky, Long, and Peritrichate Nanofibers

10.26434/chemrxiv.10001924.v1 ◽

2019 ◽

Author(s):

Yoshihide Furuichi ◽

Shogo Yoshimoto ◽

Tomohiro Inaba ◽

Nobuhiko Nomura ◽

Katsutoshi Hori

Keyword(s):

Formation Process ◽

Biofilm Formation ◽

Extracellular Polymeric Substances ◽

Waste Treatment ◽

Large Cell ◽

Dlvo Theory ◽

Bacterial Cells ◽

Chemical Production ◽

Discontinuous Surface ◽

Cell Cell

Biofilms are used in environmental biotechnologies including waste treatment and environmentally friendly chemical production. Understanding the mechanisms of biofilm formation is essential to control microbial behavior and improve environmental biotechnologies. Acinetobacter sp. Tol 5 autoagglutinate through the interaction of the long, peritrichate nanofiber protein AtaA, a trimeric autotransporter adhesin. Using AtaA, without cell growth or the production of extracellular polymeric substances, Tol 5 cells quickly form an unconventional biofilm. In this study, we investigated the formation process of this unconventional biofilm, which started with cell–cell interactions, proceeded to cell clumping, and led to the formation of large cell aggregates. The cell–cell interaction was described by DLVO theory based on a new concept, which considers two independent interactions between two cell bodies and between two AtaA fiber tips forming a virtual discontinuous surface. If cell bodies cannot collide owing to an energy barrier at low ionic strengths but approach within the interactive distance of AtaA fibers, cells can agglutinate through their contact. Cell clumping proceeds following the cluster–cluster aggregation model, and an unconventional biofilm containing void spaces and a fractal nature develops. Understanding its formation process would extend the utilization of various types of biofilms, enhancing environmental biotechnologies.

Download Full-text