Matrix Of Extracellular Polymeric Substances Research Articles

Lysine aggregates‐based nanostructured antimicrobial peptides for cariogenic biofilm microenvironment‐activated caries treatment

AbstractDental caries is one of the most prevalent and costly biofilm‐induced oral diseases that causes the deterioration of the mineralized tooth tissue. Traditional antimicrobial agents like antibiotics and antimicrobial peptides (AMPs) struggle to effectively eradicate bacteria in biofilms without eliciting resistance. Herein, we demonstrate the construction of FeOOH@Fe‐Lysine@Au nanostructured AMPs (nAMPs) distinguished by their AMP‐like antibacterial activity and self‐producing reactive oxygen species (ROS) capacity for caries treatment. On the one hand, FeOOH@Fe‐Lysine@Au nAMPs can catalyze glucose oxidation to generate ROS within the cariogenic biofilm microenvironment, resulting in the disintegration of the extracellular polymeric substance matrix and the exposure of bacteria. On the other hand, FeOOH@Fe‐Lysine@Au nAMPs can attach to bacterial surfaces via electrostatic attractions, proceeding to damage membranes, disrupt metabolic pathways, and inhibit protein synthesis through the aggregated lysine and the generated ROS. Based on this antibacterial mechanism, FeOOH@Fe‐Lysine@Au nAMPs can effectively eradicate Streptococcus mutans and its associated biofilm, significantly impeding the progression of dental caries. Given the straightforward and cost‐efficient preparation of FeOOH@Fe‐Lysine@Au nAMPs compared to AMPs that require specific sequences, and their minimal adverse impacts on gingival/palatal tissues, major organs, and oral/gut microbiomes, our research may promote the development of novel therapeutic agents in dental health maintenance.

Antibiofilm Potential of Aqueous Extracts of Garcinia kola against ‎Salmonella species in Greater Cane Rat (Thryonomys swinderianus, ‎Temmink 1827) from Badagry, Lagos State, Nigeria

Biofilms encompass a cluster of microorganisms encased in a slimy matrix of extracellular polymeric substances, which imbibe antibiotic resistance. Salmonella specie is a major bacterial cause of food-borne diseases in both humans and animals. The prevalence of Salmonella species is increasing which may form biofilm, and bacteria that form biofilm may be more resistant to antimicrobial agents. This study is intended to determine the presence and antimicrobial susceptibility patterns of Salmonella species among greater cane rats and carry out the biofilm formation of isolated Salmonella species and dispersion using Garcinia kola. A total of 20 cane rats were obtained from a farm in Lagos state and roadside hunters. Samples of rectal swabs were collected aseptically for bacterial culture. Bacteria isolation was done with selective media using standard bacteriological techniques following pre-enrichment of the samples with buffered peptone water. Gram staining and biochemical tests were used for confirmation of the organisms. An antimicrobial susceptibility test was performed following standard protocol. Zones of inhibition were measured and categorized as totally sensitive and resistant. Nine (9) isolates of Salmonella species were obtained from rectal swabs of greater cane rats. A modified crystal violet assay was employed to develop biofilm and test the effect of a crude extract of Garcinia kola on biofilm dispersal. Data obtained from this study was subjected to statistical analysis using descriptive statistics and paired t-test at a level of significance of P ≤ 0.05. The overall prevalence of Salmonella species obtained in this study was 45%. Antimicrobial study showed susceptibility of 77.8% for Chloramphenicol and 66.7% for Cefuroxime while all isolates were 100% susceptible to Amikacin and Gentamicin. The effect of Garcinia kola extract on different isolates at 430nm showed a significant difference (p= 0.0348) in biofilm formation in isolates with Garcinia kola extract when compared with isolates without extract. The effect of Garcinia kola extract on different isolates at 650nm elicited significant (p = 0.0216) biofilm inhibitions across the isolates. The antibiofilm activity displayed by Garcinia kola suggests its potential to serve as an alternative antimicrobial agent to combat drug resistant bacteria such as Salmonella species. However, further investigations should be carried out on the individual bioactive compounds to know the exact metabolites responsible for the antibiofilm activity of this bacteria species.

Anti-Biofilm Strategies: A Focused Review on Innovative Approaches.

Biofilm (BF) can give rise to systemic infections, prolonged hospitalization times, and, in the worst case, death. This review aims to provide an overview of recent strategies for the prevention and destruction of pathogenic BFs. First, the main phases of the life cycle of BF and maturation will be described to identify potential targets for anti-BF approaches. Then, an approach acting on bacterial adhesion, quorum sensing (QS), and the extracellular polymeric substance (EPS) matrix will be introduced and discussed. Finally, bacteriophage-mediated strategies will be presented as innovative approaches against BF inhibition/destruction.

The dynamics of bacterial proliferation, viability, and extracellular polymeric substances in oral biofilm development

ObjectivesThis study investigated the relationship between bacterial growth, viability, and extracellular polymeric substances (EPS) formation in biofilms, particularly regarding resistance development. It also examined the impact of chemical factors on the EPS matrix and bacterial proliferation in oral biofilms. MethodsThree multi-species oral biofilms were incubated in anaerobic conditions. Three strains of Enterococcus faecalis were incubated in aerobic conditions. The incubation periods ranged from 0 h to 7 days for short-term biofilms, and from 3 to 90 days for long-term biofilms. Fluorescent labeling with carboxyfluorescein diacetate succinimidyl ester (CFSE) and flow cytometry were used to track EPS and bacterial growth. Confocal laser scanning microscopy (CLSM) assessed bacterial viability and EPS structure. Biofilms aged 7, 14, and 21 days were treated with 2 % chlorhexidine (CHX) and 1 % sodium hypochlorite (NaOCl) to evaluate their effects on EPS and bacterial proliferation. ResultsShort-term biofilms showed rapid bacterial proliferation and a gradual increase in EPS, maintaining stable viability. In the first two weeks, a significant rise in CFSE indicated growing maturity. From 14 to 90 days, EPS and CFSE levels stabilized. Following treatment, CHX significantly reduced bacterial proliferation, while NaOCl decreased EPS volume. ConclusionsBiofilm development involves a balance between bacterial proliferation and EPS production. The complexity of this process poses challenges in treating biofilm-associated infections, requiring strategies tailored to the biofilm's developmental stage. Clinical significanceFor effective root canal treatment, it is imperative to focus on reducing bacterial proliferation during the early stages of oral infections. In contrast, strategies aimed at minimizing EPS production could be more beneficial for long-term management of these conditions.

Adaptive mechanism of the marine bacterium Pseudomonas sihuiensis-BFB-6S towards pCO2 variation: Insights into synthesis of extracellular polymeric substances and physiochemical modulation

Marine bacteria can adapt to various extreme environments by the production of extracellular polymeric substances (EPS). Throughout this investigation, impact of variable pCO2 levels on the metabolic activity and physiochemical modulation in EPS matrix of marine bacterium Pseudomonas sihuiensis - BFB-6S was evaluated using a fluorescence microscope, excitation-emission matrix (EEM), 2D-Fourier transform infrared correlation spectroscopy (2D-ATR-FTIR-COS), FT-NMR and TGA-DSC. From the results at higher pCO2 levels, there was a substantial reduction in EPS production by 58–62.8 % (DW). In addition to the biochemical composition of EPS, reduction in carbohydrates (8.7–47.6 %), protein (7.1–91.5 %), and lipids (16.9–68.6 %) content were observed at higher pCO2 levels. Functional discrepancies of fluorophores (tyrosine and tryptophan-like) in EPS, speckled differently in response to variable pCO2. The 2D-ATR-FTIR-COS analysis revealed functional amides (CN, CC, CO bending, -NH bending in amines) of EPS were preferentially altered, which led to the domination of polysaccharides relevant functional groups at higher pCO2. 1H NMR analysis of EPS confirmed the absence of chemical signals from H-C-COOH of proteins, α, β anomeric protons, and acetyl group relevant region at higher pCO2 levels. These findings can contribute new insights into the influence of pCO2 on the adaptation of marine microbes in future ocean acidification scenarios.

Altering the interfacial rheology of Pseudomonas aeruginosa and Staphylococcus aureus with N-acetyl cysteine and cysteamine.

Chronic lung infection due to bacterial biofilms is one of the leading causes of mortality in cystic fibrosis (CF) patients. Among many species colonizing the lung airways, Pseudomonas aeruginosa and Staphylococcus aureus are two virulent pathogens involved in mechanically robust biofilms that are difficult to eradicate using airway clearance techniques like lung lavage. To remove such biological materials, glycoside hydrolase-based compounds are commonly employed for targeting and breaking down the biofilm matrix, and subsequently increasing cell susceptibility to antibiotics. In this study, we evaluate the effects of N-acetyl cysteine (NAC) and Cysteamine (CYST) in disrupting interfacial bacterial films, targeting different components of the extracellular polymeric substances (EPS). We characterize the mechanics and structural integrity of the interfacial bacterial films using pendant drop elastometry and scanning electron microscopy. Our results show that the film architectures are compromised by treatment with disrupting agents for 6 h, which reduces film elasticity significantly. These effects are profound in the wild type and mucoid P. aeruginosa, compared to S. aureus. We further assess the effects of competition and cooperation between S. aureus and P. aeruginosa on the mechanics of composite interfacial films. Films of S. aureus and wild-type P. aeruginosa cocultures lose mechanical strength while those of S. aureus and mucoid P. aeruginosa exhibit improved storage modulus. Treatment with NAC and CYST reduces the elastic property of both composite films, owing to the drugs' ability to disintegrate their EPS matrix. Overall, our results provide new insights into methods for assessing the efficacy of mucolytic agents against interfacial biofilms relevant to cystic fibrosis infection.

Chemical multiscale robotics for bacterial biofilm treatment.

A biofilm constitutes a bacterial community encased in a sticky matrix of extracellular polymeric substances. These intricate microbial communities adhere to various host surfaces such as hard and soft tissues as well as indwelling medical devices. These microbial aggregates form a robust matrix of extracellular polymeric substances (EPSs), leading to the majority of human infections. Such infections tend to exhibit high resistance to treatment, often progressing into chronic states. The matrix of EPS protects bacteria from a hostile environment and prevents the penetration of antibacterial agents. Modern robots at nano, micro, and millimeter scales are highly attractive candidates for biomedical applications due to their diverse functionalities, such as navigating in confined spaces and targeted multitasking. In this tutorial review, we describe key milestones in the strategies developed for the removal and eradication of biofilms using robots of different sizes and shapes. It can be seen that robots at different scales are useful and effective tools for treating bacterial biofilms, thus preventing persistent infections, the loss of costly implanted medical devices, and additional costs associated with hospitalization and therapies.

Quaternary ammonium-tethered hyperbranched polyurea nanoassembly synergized with antibiotics for enhanced antimicrobial efficacy.

The effective transportation of antibiotics to bacteria embedded within a biofilm consisting of a dense matrix of extracellular polymeric substances is still a challenge in the treatment of bacterial biofilm associated infections. Here, we developed an antibiotic nanocarrier constructed from quaternary ammonium-tethered hyperbranched polyureas (HPUs-QA), which showed high loading capacity for a model antibiotic, rifampicin, and high efficacy in the transportation of rifampicin to biofilms. The rifampicin-loaded HPUs-QA nanoassembly (HPUs-Rif/QA) demonstrated a synergistic antimicrobial effect in killing planktonic bacteria and eradicating the corresponding biofilms. Compared to the treatment of bacteria-infected chronic wounds by either HPUs-QA or rifampicin alone, HPUs-Rif/QA showed superior efficacy in promoting wound healing by more effectively inhibiting bacteria colonization. This study highlights the potential of the HPUs-QA nanoassembly in synergistic action with antibiotics for the treatment of biofilm associated infections.

Analysis of Protein Profile and Functional Groups in Biofilms in the Hypersaline Environment

Halophilic microorganisms include extremophiles that can live and develop in a hypersaline environment. Biofilm, as microecology, consists of a collection of microorganisms attached to a surface, forming an Extracellular Polymeric Substance (EPS) matrix. This study aims to analyze the protein profile and functional groups of biofilms that grow in hypersaline environments. The method used in this study is the SDS PAGE test to diagnose protein profiling and FTIR to analyze biofilm functional groups. The samples used to grow the biofilm came from salt ponds with different NaCl levels, namely 2%, 25%, and 40%. The results showed that each NaCl treatment had different functional groups in the biofilm samples. In the 2% NaCl treatment, there were peaks with solid intensity at the wavenumber 1100 cm-1, indicating the carboxylic acid functional group. In the 25% NaCl treatment, peaks with solid intensity at wavenumber 2250 cm-1 indicate the isocyanate functional group. In the 40% NaCl treatment, there were peaks with solid intensity at wavenumber 860 cm-1, indicating the alkene functional group. The protein analysis for each treatment shows the presence of pyruvate kinase protein in the biofilm with 2% NaCl. The 25% NaCl biofilm sample contained avidin protein, and the 40% NaCl biofilm sample contained tyrosine protein.

Enhanced short-chain fatty acids production from anaerobic fermentation of secondary sludge by lignosulfonate addition: Towards circular economy

This study is the first to unveil the potential of lignosulfonate as an additive in the production of short-chain fatty acids (SCFAs) from anaerobic fermentation of secondary sludge. Batch-scale tests were performed to assess SCFAs production and distribution with lignosulfonate addition of 20–80 mg/g volatile solids (VS), along with potential mechanisms and phytotoxicity. The results showed that lignosulfonate addition improved the SCFAs production and the ratio of acetic acid, while shortening the fermentation time required. The maximum SCFAs production (185.0 ± 1.0 mg COD/g VS) and acetic acid ratio (51.4 ± 0.6%) were achieved with 60 mg lignosulfonate/g VS at 4 d of fermentation time, outperforming the control (93.1 ± 2.7 mg COD/g VS, 44.4 ± 1.8%). Lignosulfonate addition decreased the zeta potential between sludge particles by 19.9%–45.1%, and increased the extractable extracellular polymeric substances matrix by 1.45–2.33 times, compared to the control group. Furthermore, lignosulfonate addition effectively promoted the solubilization, hydrolysis, and acidification processes by up to 116.0%, 58.8%, and 47.6%, respectively. The seed germination index of Chinese cabbage and lettuce using fermented sludge residues increased by up to 486 ± 29% and 158 ± 13%, respectively. These findings suggest that lignosulfonate addition is a sustainable method for SCFAs recovery from sludge, benefiting sludge agricultural reuse, and contributing to the circular economy.

Insights into the interaction between mineral formation and heavy metals immobilization, mediated by Virgibacillus exopolymeric substances

Heavy metal pollution poses significant risks to both the environment and human health due to their toxicity, long residence times, and their ability to bioaccumulate and bio magnify across the food chain. To address this issue, microbial biomineralization has emerged as a promising approach to the bio-removal of heavy metals through immobilization. This process is facilitated by extracellular polymeric substances (EPS), which also play a crucial role in mediating mineral formation. In this study, the interactions between several selected heavy metals (Cd2+, Cu2+, Ni2+, Zn2+), EPS, and mineral formation were investigated using two mineral-forming Virgibacillus strains isolated from the Qatari sabkhas, which are known to be suitable sites for the formation of biominerals. An additional non-mineral-forming Virgibacillus strain isolated from the Dukhan oil waste dumpsite was also investigated. Cd2+ and Zn2+ were to inhibit mineral formation, likely due to competition with Ca2+ and Mg2+ ions during biomineralization. However, exposure to Ni2+ or Cu2+ resulted in changes in the FTIR spectra of the EPS, suggesting the presence of specific functional group bindings within the EPS matrix. The EPS produced by each strain was also directly associated with their efficiency (%) at removing heavy metals. Notably, the EPS from Virgibacillus halodenitrificans Z4D1, the non-mineral-forming strain, exhibited the highest heavy metal removal efficiency of 31.7 % for Zn2+. These findings reveal that EPS do not only affect the biomineralization process but also that the functional groups in EPS have a direct effect on the immobilization of several heavy metals. Conditions that are not suitable for mineral formation may instead be appropriate for the removal of specific heavy metals.

Multi-omics analysis reveals genes and metabolites involved in Bifidobacterium pseudocatenulatum biofilm formation.

Bacterial biofilm is an emerging form of life that involves cell populations living embedded in a self-produced matrix of extracellular polymeric substances (EPS). Currently, little is known about the molecular mechanisms of Bifidobacterium biofilm formation. We used the Bifidobacterium biofilm fermentation system to preparation of biofilms on wheat fibers, and multi-omics analysis of both B. pseudocatenulatum biofilms and planktonic cells were performed to identify genes and metabolites involved in biofilm formation. The average diameter of wheat fibers was around 50 μm, while the diameter of particle in wheat fibers culture of B. pseudocatenulatum was over 260 μm at 22 h with 78.96% biofilm formation rate (BR), and the field emission scanning electron microscopy (FESEM) results showed that biofilm cells on the surface of wheat fibers secreted EPS. Transcriptomic analysis indicated that genes associated with stress response (groS, mntH, nth, pdtaR, pstA, pstC, radA, rbpA, whiB, ybjG), quorum sensing (dppC, livM, luxS, sapF), polysaccharide metabolic process (rfbX, galE, zwf, opcA, glgC, glgP, gtfA) may be involved in biofilm formation. In addition, 17 weighted gene co-expression network analysis (WGCNA) modules were identified and two of them positively correlated to BR. Metabolomic analysis indicated that amino acids and amides; organic acids, alcohols and esters; and sugar (trehalose-6-phosphate, uridine diphosphategalactose, uridine diphosphate-N-acetylglucosamine) were main metabolites during biofilm formation. These results indicate that stress response, quorum sensing (QS), and EPS production are essential during B. pseudocatenulatum biofilm formation.

Cultivation of Cyanobacteria on Sustainable Dried Luffa cylindrica

Cyanobacteria are promising organisms for the sustainable production of various biotechnological interesting products. Due to their energy production via photosynthesis, the cultivation of cyanobacteria expands the CO2 cycle. Most cyanobacteria form biofilms on surfaces in their natural environment by surrounding the cells with a self-produced matrix of extracellular polymeric substances (EPS) that hold the cells together. These special growth properties need special reactors for cultivation. By immobilizing cyanobacteria on carriers, systems currently established in industry could also be used for biofilm formers. Various artificial carriers for immobilized growth of cyanobacteria and microalgae have already been described in the literature. However, the use of waste materials or natural biodegradable carriers would be more sustainable and is, therefore, the focus of this study. Dried Luffa cylindrica, zeolite, and corn stalks were investigated for their use as carriers for cyanobacteria. L. cylindrica was shown to be an excellent natural carrier for (i) Anabaena cylindrica, (ii) Nostoc muscorum 1453-12a, and (iii) Nostoc muscorum 1453-12b. Higher or at least similar growth rates were achieved when cyanobacteria were cultivated with L. cylindrica compared to submerged cultivation. Additionally, the production of EPS and C-phycocyanin was increased at least 1.4 fold in all strains by culturing on L. cylindrica. The improved growth could be explained on the one hand by the high surface area of L. cylindrica and its properties, and, on the other hand, by the release of growth-promoting nutrients from L. cylindrica to the medium.

Theranostic gold-in-gold cage nanoparticles enable photothermal ablation and photoacoustic imaging in biofilm-associated infection models.

Biofilms are structured communities of microbial cells embedded in a self-produced matrix of extracellular polymeric substances. Biofilms are associated with many health issues in humans, including chronic wound infections and tooth decay. Current antimicrobials are often incapable of disrupting the polymeric biofilm matrix and reaching the bacteria within. Alternative approaches are needed. Here, we described a complex structure of a dextran-coated gold-in-gold cage nanoparticle that enabled photoacoustic and photothermal properties for biofilm detection and treatment. Activation of these nanoparticles with a near infrared laser could selectively detect and kill biofilm bacteria with precise spatial control and in a short timeframe. We observed a strong biocidal effect against both Streptococcus mutans and Staphylococcus aureus biofilms in mouse models of oral plaque and wound infections, respectively. These effects were over 100 times greater than those seen with chlorhexidine, a conventional antimicrobial agent. Moreover, this approach did not adversely affect surrounding tissues. We concluded that photothermal ablation using theranostic nanoparticles is a rapid, precise, and nontoxic method to detect and treat biofilm-associated infections.

Biofilms as Battlefield Armor for Bacteria against Antibiotics: Challenges and Combating Strategies.

Bacterial biofilms are formed by communities, which are encased in a matrix of extracellular polymeric substances (EPS). Notably, bacteria in biofilms display a set of 'emergent properties' that vary considerably from free-living bacterial cells. Biofilms help bacteria to survive under multiple stressful conditions such as providing immunity against antibiotics. Apart from the provision of multi-layered defense for enabling poor antibiotic absorption and adaptive persistor cells, biofilms utilize their extracellular components, e.g., extracellular DNA (eDNA), chemical-like catalase, various genes and their regulators to combat antibiotics. The response of biofilms depends on the type of antibiotic that comes into contact with biofilms. For example, excessive production of eDNA exerts resistance against cell wall and DNA targeting antibiotics and the release of antagonist chemicals neutralizes cell membrane inhibitors, whereas the induction of protein and folic acid antibiotics inside cells is lowered by mutating genes and their regulators. Here, we review the current state of knowledge of biofilm-based resistance to various antibiotic classes in bacteria and genes responsible for biofilm development, and the key role of quorum sensing in developing biofilms and antibiotic resistance is also discussed. In this review, we also highlight new and modified techniques such as CRISPR/Cas, nanotechnology and bacteriophage therapy. These technologies might be useful to eliminate pathogens residing in biofilms by combating biofilm-induced antibiotic resistance and making this world free of antibiotic resistance.

Investigation and prediction of the biotoxicity of Cu2+ to Chlorella vulgaris: modification of the biotic ligand model.

The increased copper ion (Cu2+) concentrations in aquatic ecosystem significantly influence the environmental quality and ecosystem safety, while information on the Cu2+ biotoxicity to aquatic microorganisms and the models for biotoxicity prediction are still unclear. In this study, the toxicities of Cu2+ to Chlorella vulgaris under different environmental conditions (e.g., Na+, K+, Ca2+, Mg2+, pH, and dissolved organic matter) were explored, with the experimental results in comparison with those predicted by the biotic ligand model (BLM). Results showed that increased Cu2+ concentration caused obvious toxicities to C. vulgaris, whereas the commonly occurring cations and dissolved organic matters can protect the metabolism system of C. vulgaris. The presence of extracellular polymeric substances (EPS) matrix can alleviate the biotoxicity via increasing the surface biosorption but decreasing cell internalization of Cu2+ in C. vulgaris. Due to the presence of EPS matrix, the experimental biotoxicity results under each condition were significantly lower than those predicted by the BLM model, which was thus modified via taking the EPS matrix as the supplement of allochthonous organic matters. After that, the modified BLM was characterized with a higher degree of precision and can be used in natural waters for biotoxicity prediction. Results obtained can enhance our insights into the ecological effects and biotoxicity prediction of heavy metals in natural aquatic ecosystems.

Factors Affecting Biofilms Formation in Drinking Water Distribution Systems

This article discusses the importance of microbiological safety in drinking water and the challenges drinking water treatment plants face in delivering a safe product. Biofilms, thin layers of microorganisms that adhere to surfaces and produce a slimy matrix of extracellular polymeric substances, can potentially cause health risks in drinking water if they contain harmful microorganisms. The article highlights the need for proper maintenance of the drinking water distribution system and regular testing for the presence of harmful microorganisms and other contaminants to minimize the risk of illness from biofilms. The study focuses on insufficient research on biofilms in drinking water distribution systems in Sulaimani City. It provides new and relevant information on the public health problems associated with their presence and describes current and emergent strategies for their control. The microbiological and Physio Chemical experiments were conducted on water samples from various water drinking sources in Sulaimani City to evaluate contamination of portable drinking water. Then, Most Probable Number (MPN) and Membrane Filtration methods were applied to collected water samples for the determination and presence of coliform bacteria in water. Moreover, Swab biofilm was employed within a different agar and distributed by an L shape. After that, 13 different physio-chemical tests were conducted on the previous experiments. Enterobacteriaceae had a moderately negative correlation (-0.764) with temperature and was statistically significant (Sig. = 0.000). Moreover, it was moderately positively correlated (0.416) with Chemical Oxygen Demand (COD) and statistically significant (Sig. = 0.038).

Quantitative Imaging of the Action of vCPP2319, an Antimicrobial Peptide from a Viral Scaffold, against Staphylococcus aureus Biofilms of a Clinical Isolate.

The formation of biofilms is a common virulence factor that makes bacterial infections difficult to treat and a major human health problem. Biofilms are bacterial communities embedded in a self-produced matrix of extracellular polymeric substances (EPS). In this work, we show that vCPP2319, a polycationic peptide derived from the capsid protein of Torque teno douroucouli virus, is active against preformed Staphylococcus aureus biofilms produced by both a reference strain and a clinical strain isolated from a diabetic foot infection, mainly by the killing of biofilm-embedded bacteria. The direct effect of vCPP2319 on bacterial cells was imaged using atomic force and confocal laser scanning microscopy, showing that the peptide induces morphological changes in bacterial cells and membrane disruption. Importantly, vCPP2319 exhibits low toxicity toward human cells and high stability in human serum. Since vCPP2319 has a limited effect on the biofilm EPS matrix itself, we explored a combined effect with α-amylase (EC 3.2.1.1), an EPS matrix-degrading enzyme. In fact, α-amylase decreases the density of S.aureus biofilms by 2.5-fold. Nonetheless, quantitative analysis of bioimaging data shows that vCPP2319 partially restores biofilm compactness after digestion of the polysaccharides, probably due to electrostatic cross-bridging of the matrix nucleic acids, which explains why α-amylase fails to improve the antibacterial action of the peptide.

Occurrence and Role of Bacterial Biofilms in Different Systems

Bacterial biofilms are complex communities of bacteria that adhere to surfaces, including living tissues, and form a protective matrix of extracellular polymeric substances (EPS). Biofilms are widespread and play crucial roles in various processes, such as nutrient cycling, bioremediation, and biofouling. They have significant implications for public health. Biofilms provide an ideal environment for bacteria to exchange genetic material, including resistance genes, via horizontal gene transfer mechanisms such as conjugation, transformation, and transduction. Moreover, biofilms can protect bacteria from antibiotics and host immune responses, enabling them to persist and cause chronic infections. The EPS matrix, which can act as a physical barrier, limits the penetration of antibiotics into the biofilm, and the slow-growing or dormant cells within the biofilm are less susceptible to antibiotics than their planktonic counterparts. The significance of bacterial biofilms in the development of antibiotic resistance has prompted research efforts to understand their formation and mechanisms of resistance. Novel strategies to prevent or disrupt biofilm formation are also being explored, including the development of antibiofilm agents and biofilm-disrupting enzymes. Understanding the role of biofilms in the spread of antibiotic resistance is crucial for the development of effective treatment and prevention strategies to combat the chronic infections associated with biofilm-producing bacteria.

Microbial Biofilms: Harnessing the Power of Complex Microbial Communities for Industrial Applications

Microbial biofilms are complex microbial colonies that attach to surfaces and grow inside an extracellular polymeric substance (EPS) matrix. These biofilms have great promise for industrial applications and play crucial roles in several natural and artificial systems. The use of microbial biofilms in industrial settings is examined in this abstract, which also places an emphasis on techniques to improve biofilm development and performance through surface modification and quorum sensing manipulation. Due to their versatility, durability, and cooperative behaviour, biofilms have attracted interest and are useful in a variety of industrial industries. They work in the food business, bioenergy generation, agriculture industry and biosensor, among other fields.Biofilms are more effective in industrial processes because of their intricate interactions, which also lead to higher metabolic capacities, increased stress tolerance, and improved retention of immobilised cells. The production and performance of microbial biofilms need to be improved in order to fully realise their potential. Techniques for surface modification provide a promising way to customise the characteristics of biofilms. It is possible to modify the topography, hydrophobicity, and charge of the substrate to affect how quickly biofilms form after initial microbial attachment. Additionally, functionalization and coatings based on nanomaterials provide novel approaches to improve biofilm adhesion, cohesiveness, and stability. The method of cell-to-cell communication known as quorum sensing (QS) directs the development and behaviour of biofilms. Controlling QS pathways enables fine-grained regulation of biofilm growth. QS may be controlled via genetic engineering and small molecule therapy, which affects the phenotypic and architecture of biofilms. With the use of these techniques, biofilms may be designed with the required properties, including greater thickness, higher resistance to shear pressures, and increased production of desirable chemicals. In conclusion, because of their cooperative nature and adaptable functioning, microbial biofilms show enormous promise for industrial applications. The importance of surface modification and quorum sensing modulation as tactics to improve biofilm performance is highlighted in this abstract. As science advances, a fuller comprehension of the ecology of biofilms, interspecies interactions, and synthetic biology technologies will make it easier to create biofilms that are specifically suited to a given industrial purpose. Understanding the complex principles underlying biofilm production and behaviour will allow for the full realisation of the promise for sustainable and effective industrial processes, ushering in a new age of biofilm-based technology.