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This study evaluated surface properties and adhesion/biofilm formation by Candida albicans on 3D printed denture base resins used in 3D printing. Disc-shaped specimens (15 mm x 3 mm) of two 3D-printed resins (NextDent Denture 3D+, NE, n = 64; and Cosmos Denture, CO, n = 64) and a heat-polymerized resin (Lucitone 550, LU, control, n = 64) were analyzed for surface roughness (Ra μm) and surface free energy (erg cm-2). Microbiologic assays (90-min adhesion and 48-h biofilm formation by C. albicans) were performed five times in triplicate, with the evaluation of the specimens' surface for: (i) colony forming units count (CFU/mL), (ii) cellular metabolism (XTT assay), and (iii) fluorescence and thickness of biofilm layers (confocal laser scanning microscopy). Data were analyzed using parametric and nonparametric tests (α = 0.05). LU presented higher surface roughness Ra (0.329±0.076 μm) than NE (0.295±0.056 μm) (p = 0.024), but both were similar to CO (0.315±0.058 μm) (p = 1.000 and p = 0.129, respectively). LU showed lower surface free energy (47.47±2.01 erg cm-2) than CO (49.61±1.88 erg cm-2) and NE (49.23±2.16 erg cm-2) (p<0.001 for both). The CO and NE resins showed greater cellular metabolism (p<0.001) and CO only, showed greater colonization (p = 0.015) by C. albicans than LU in the 90-min and 48-hour periods. It can be concluded that both 3D-printed denture base resins are more prone to colonization by C. albicans, and that their surface free energy may be more likely associated with that colonization than their surface roughness. [ABSTRACT FROM AUTHOR]

Polymer cables are being applied increasingly in fields such as deep‐sea mooring and cage culture. How to improve their wear resistance and prevent microbial adhesion is an urgent problem to be solved. In this work, the surface of the cable was treated by the polyvinylpyrrolidone cross‐linking method and the anchoring effect of one‐dimensional linear nanomaterials, which improved the adhesion of the water‐based coating. Meanwhile, the protective effect of the coating was improved through the addition of antifouling agents and wear‐resistant agents. The microstructure and intermolecular forces of the coating were characterized by scanning electron microscopy and infrared spectroscopy. The net hanging test results show that the surface‐treated cable exhibits better abrasion resistance and antifouling effects, and the shedding phenomenon is significantly improved. [ABSTRACT FROM AUTHOR]

Diffuse coplanar surface barrier discharge (DCSBD) was used to activate the opposite side of the plasma‐exposed linear low‐density polyethylene/polyamide (LLDPE/PA) tubular film of multilayer casing. We determined that conductive metal rubber roller in the DCSBD system allowed the formation of microfilaments perpendicular to the film surface, resulting in improved wettability and adhesion of inner LLDPE side of the tubular film. These findings were supported by increasing the concentration of polar functional groups. Based on these remarkable outcomes obtained after a very short plasma exposure time of 0.5 s, DCSBD roll‐to‐roll system in proper arrangement affords adhesion improvement of the opposite side of the treated film without any material damage, hence can compete with industrial corona in commercial sphere of plasma treatments. [ABSTRACT FROM AUTHOR]

Quaternary ammonium salts (QAS) are widely used in medicine, industry and agriculture as disinfectants, biocides, and fungicides. QAS have the ability to coat various surfaces, prevent adhesion of microorganisms to them and inhibit the formation of biofilm. A group of surfactants derived from benzoic acid with different chemical structures was tested: monomeric QAS with different alkyl chain lengths (C 12 , C 14 , C 16), gemini QAS containing 12-carbon alkyl chains and linkers of various lengths (3,4,6 methylene groups), as well as multifunctional QAS. Among the tested surfactants, monomeric QAS showed the highest bactericidal and fungicidal activity. All three groups of tested compounds inhibited the filamentation of C. albicans. The best antimicrobial activity was demonstrated by the monomeric surfactant C 12 AA, while the multifunctional equivalent (2xC 12 AA) was characterized by good anti-adhesive activity. All tested compounds are non-mutagenic and cause low hemolysis of sheep erythrocytes. Multifunctional and gemini surfactants are also non-toxic. [Display omitted] • Monomeric surfactants show strong activity against planktonic bacteria and fungi. • Multifunctional surfactant was characterized by good anti-adhesive activity. • Monomeric and gemini quaternary ammonium salts inhibit Candida albicans filamentation. • Gemini and monomeric quaternary ammonium salts are non-mutagenic. • Quaternary ammonium salts induce low hemolysis of sheep erythrocytes. [ABSTRACT FROM AUTHOR]

BACKGROUND Adhesion is considered important for Lactiplantibacillus to persist in the human gut and for it to exert probiotic effects. Lactiplantibacillus plantarum contains a considerable number and variety of genes encoding bile salt hydrolases (bsh), but their effects on microbial adhesion remain poorly understood. To clarify the effects of four bsh on adhesion, we tried to knock out bsh (Δbsh) of L. plantarum AR113 using the CRISPR‐Cas9 method, and compared the growth, auto‐aggregation (RAA), co‐aggregation (RCA), surface hydrophobicity (AHC) of AR113 wild‐type and Δbsh strains and their adhesion abilities to HT29 cells. RESULTS: We first obtained the AR113 Δbsh1,3,2,4 strain with four bsh knocked out. Their growth was significantly slower than the wild‐type strain cultured in De Man, Rogosa, and Sharpe medium (MRS) with 3.0 g L−1 glyco‐ or tauro‐conjugated bile acid. Bsh had no significant effect on the growth of ten strains cultured in MRS, but Δbsh1 inhibited their growth when cultured in MRS containing 3.0 g L−1 sodium glycocholate, whereas Δbsh4 instead promoted their growth in MRS with 3.0 g L−1 sodium glycocholate and sodium taurocholate. RCA and RAA were linearly positive for all strains except AR113 Δbsh2,4, and AHC and RAA were negatively correlated for most strains excluding AR113 Δbsh2, with RAA = 6.38–25.05%, RCA = 5.17–9.22%, and ACH = 3.22–47.71%. The adhesion ability of ten strains cultured in MRS was higher than that of strains cultured in MRS with 3.0 g L−1 bovine bile, and it was related to bsh2. CONCLUSION: Bsh differentially affected the adhesion of AR113 series strains. This adds to the available information about substrate‐gene‐performance, and provides new information to enable engineering to regulate the colonization of Lactiplantibacillus. © 2021 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Microbial adhesion to surfaces is thought to involve physicochemical interactions between the substrate and microbial cells. Understanding the physicochemical aspects involved in the adhesion phenomenon, as a critical step in biofilm formation, is essential to finding ways to prevent their formation and control biocontamination risks. The aim of this study was to investigate the relation between the adhesion behavior of 12 Escherichia coli strains isolated from food and their surface hydrophobicities using qualitative ( θ w ) and quantitative (ΔGiwi) approaches. The surface physicochemical properties of both bacterial cells and glass material were estimated through contact angle measurements. The adhesive behavior of E. coli strains on a glass surface was assessed. The results showed a good logarithmic relation between the percentage of the adhered cells and their surface hydrophobicity with the quantitative approach ΔGiwi; however, qualitative hydrophobicity ( θ w ) appeared to demonstrate no effect regarding adhesion behavior. This work lays the foundation for future studies and opens an important debate on the mechanisms underlying the adhesion behavior of E. coli strains by using the thermodynamic approach (ΔGiwi) as an important model of hydrophobicity that could explain and predict better bacterial adhesion ability. [ABSTRACT FROM AUTHOR]

Bacterial contamination of surfaces is a natural and spontaneous process that often results in the formation of biofilms. The extracellular matrix of biofilm is mostly composed of proteins, polysaccharides, and extracellular DNA and is responsible for the strong persistent ability of biofilm in the food industry. Despite cleaning and disinfection processes, persistent bacteria cause a major problem in food processing environments. Synthetic surfactants, mainly anionic surface‐active agent, are commonly used as detergents, foaming agents, wetting agents, emulsifiers, and dispersants. Their tendency to adsorb to surfaces and interfaces and modify their surface tension, is considered among their main properties. They also have the ability to attach to bioactive macromolecules such as proteins, peptides, and DNA causing cell membrane damage. In order to estimate the adhesion kinetic and proliferation of pathogenic bacteria Staphylococcus aureus, the surface of glass was coated with anionic surfactant Sodium Lauryl Sulfate (SLS). Moreover, SLS was added in suspension with the culture medium. The physicochemical properties of the material were calculated using the contact angle measurement method and bacterial hydrophobicity using the microbial adhesion to hydrocarbons (MATH) test. The obtained results showed that the number of adhering cells increased gradually as a function of time. However, changing the surface properties of the glass and S. aureus has affected the rate of adherent cells with time as well as their organization. SLS inhibited the attachment of cells, whether it is added with the microbial suspension or at the surface of the support. Generally, the present article points to a relationship between the microbial adhesion, the surface chemistry of the solid material and the bacteria, and the suspension properties. [ABSTRACT FROM AUTHOR]

Quaternary ammonium salts (QASs) are ubiquitous in nature, being found in organisms ranging from microorganisms to vertebrates (e.g., glycine betaine, carnitine) where they have important cellular functions. QASs are also obtained by chemical synthesis. These compounds, due to their diverse chemical structure (e.g. monomeric QAS or gemini) and their biological properties, are widely used in medicine (as disinfectants, drugs, and DNA carriers), industry, environmental protection and agriculture (as preservatives, biocides, herbicides and fungicides). Discussed chemical compounds reduce the adhesion of microorganisms to various biotic and abiotic surfaces and cause the eradication of biofilms produced by pathogenic microorganisms. The properties of these chemicals depend on their chemical structure (length of the alkyl chain, linker and counterion), which has a direct impact on the physicochemical and biological activity of these compounds. QASs by incorporation into the membranes, inhibit the activity of proteins (H+-ATPase) and disrupt the transport of substances to the cell. Moreover, in the presence of QASs, changes in lipid composition (qualitative and quantitative) of plasma membrane are observed. The widespread use of disinfectants in commercial products can induce resistance in microorganisms to these surfactants and even to antibiotics. In this article we discuss the biological activity of QASs as cationic surfactants against microorganisms and their resistance to these compounds. [ABSTRACT FROM AUTHOR]

Probing the binding between a microbe and surface is critical for understanding biofilm formation processes, developing biosensors, and designing biomaterials, but it remains a challenge. Here, we demonstrate a method to measure the interfacial forces of bacteria attached to the surface. We tracked the intrinsic fluctuations of individual bacterial cells using an interferometric plasmonic imaging technique. Unlike the existing methods, this approach determined the potential energy profile and quantified the adhesion strength of single cells by analyzing the fluctuations. This method provides insights into biofilm formation and can also serve as a promising platform for investigating biological entity/surface interactions, such as pathogenicity, microbial cell capture and detection, and antimicrobial interface screening. [ABSTRACT FROM AUTHOR]

In 2006 Armstrong, Painter, and Sherratt formulated a nonlocal differential equation model for cell-cell adhesion. For the one-dimensional case on a bounded domain we derive various types of biological boundary conditions, describing adhesive, repulsive, and neutral boundaries. We prove local and global existence and uniqueness for the resulting integrodifferential equations. In numerical simulations we consider adhesive, repulsive, and neutral boundary conditions, and we show that the solutions mimic known behavior of uid adhesion to boundaries. In addition, we observe interior pattern formation due to cell-cell adhesion. [ABSTRACT FROM AUTHOR]

Interactions between microorganisms and clay minerals are ubiquitous in nature and are involved in the formation and transformation of clay minerals and the global cycles of many elements. The fungi/actinomyces in microbes are also associated with clay minerals, but bacteria are more widely linked. These interactions are also involved in the adsorption and fixation of heavy metals and the decomposition of organic pollutants in soil. Knowledge of these interactions can be utilised for the refinement and purification of clay minerals in industry. This review provides an overview of recent studies and obtains insights into the interactions between microorganisms and clay minerals. Microorganisms can induce the nucleation and growth of clay minerals. The metabolism of microorganisms can also degrade and transform clay minerals. The interaction between microorganisms and clay minerals promots the transformation of smectite to illite (S-I) and vice versa (I-S). Such interactions significantly contribute to the global cycles of various elements, such as Al, Si, Mg, Fe, P, S, C, and N. Microorganisms and clay minerals can form complexes and composite materials that adsorb heavy metals such as Cu, Cr, Cd, Pb, Zn, Co, Ni, Ag, and Hg. Microorganism adhesion to clay minerals is involved in the synergistic adsorption and decomposition of organic pollutants in soil and water. This literature review indicates that knowledge of the interactions between microorganisms and clay minerals has been significantly deepened over recent years. However, the interaction between microorganisms and clay minerals under natural geological conditions and the inherent mechanisms involved are not yet well understood. Future work on interactions between microorganisms and clay minerals has great implications for handling atmospheric micro/nano particle pollutants, understanding the formation, alteration and diagenesis of clay minerals and other related minerals, tracking primitive life on Earth and exploring extraterrestrial planets. Unlabelled Image • Recent insights into interactions between microorganisms and clay minerals • Roles of microorganisms in formation and transformation of clay minerals • Global cycles of elements, soil formation and organic matter preservation • Adsorption and elimination of pollutants and purification of clay minerals • Future work on interactions between microorganisms and clay minerals [ABSTRACT FROM AUTHOR]

Most of the microorganisms display adhesion molecules on their surface which help them to bind and interact with the host cell during infection. Adhesion molecules help mycobacteria to colonize and invade immune system of the host, and also trigger immune response explicated by the host against the infection. Hence, understanding the signalling pathways illustrated by these molecules to enhance our knowledge on mycobacterial survival and persistence inside the host cell is required. Hence, this review was focussed on the role of adhesion molecules and their receptor molecules. The various mechanisms adopted by adhesion molecules to bind with the specific receptors on the host cell and their role in invasion and persistence of mycobacterium inside the host cell are explained. [ABSTRACT FROM AUTHOR]

Gram-negative bacteria produce repeats-in-toxin adhesion proteins (RTX adhesins) to facilitate microbial adhesion. These large, multidomain proteins share a common architecture comprised of four regions. First to emerge from the bacterium, C terminal end leading, is the RTX export sequence that directs the protein through the type 1 secretion system (T1SS). This is followed by the ligand-binding region responsible for host adhesion and cohesion, which contains diverse ligand-binding domains. These serve a zip code function to direct bacteria to a particular environmental niche. Thereafter is a large extension region consisting of tens to hundreds of tandem bacterial immunoglobulin-like (BIg) domains, whose function is to extend the reach of the ligand-binding domains away from the bacterial surface. Lastly, there is a conserved N terminal cell-membrane-anchor region that retains the adhesin within the secretion system. This is also a site of in situ proteolysis, when nutrients are scarce, that enables the bacterium to leave the biofilm. In this review, the four regions of RTX adhesins are presented in the order in which they emerge from the cell during synthesis and retention. Highlights RTX adhesins are megaproteins displayed on the bacterial surface via passage through the type 1 secretion system. At the distal end of these long adhesins are ligand-binding domains of different types that determine the substrates and partners to which the bacteria bind when forming biofilms. Knowledge about these binding domains and their ligands could be used to weaken, enhance, or alter biofilm formation. At the proximal end of the RTX adhesins are domains that can retain the protein in the outer membrane with a built-in proteolytic release mechanism. [ABSTRACT FROM AUTHOR]

The physical essence of the formation and influence of bacteria on the surface of technological equipment in the dairy industry is considered as an essential factor leading to contamination of dairy products and is a major hygienic problem. The ability of microorganisms on the surfaces of technological equipment to form biofilm forms and requirements for steel grade, relief, and its roughness were analysed. The effect of surface roughness on promoting or preventing adhesion and reproduction of biofilm forms of bacteria, which reduce the efficiency of sanitary processing of dairy equipment and thereby increase the microbial contamination of dairy products with shortened shelf life, is substantiated. Research about the process of bacterial adhesion to the surface of metals with different roughness depending on the size and shape is presented. It is found that on the surface of stainless steel with roughness 2.687 ±0.014 micron film formation process in Escherichia coli and Staphylococcus aureus are similar from 3 to 24 hours and does not depend on the size of the bacteria, and accordingly allows us to argue that rod-shaped and coccid bacteria attach freely in the hollows of the roughness are the beginning of the process of the first stage of biofilm formation. It is found that on the surface of stainless steel with roughness 0.95 ±0.092 micron film formation process in S. aureus is more intense than in E. coli. Thus, within 3 hours of incubation, the density of biofilms formed S. aureus was 1.2 times bigger than biofilms E. coli, by the next 15 hours of incubation formed biofilms S. aureus were, on average, 1.3 times denser. It is established that S. aureus due to its spherical shape is able to fit in the hollows of the roughness 0.95 ±0.092 μm and faster to adhere to the surface at the same time. E. coli, due to its rod-like shape, with such surface roughness, can adhere to the cavities only over its entire length. It is proved that by surface roughness 0.63 ±0.087 μm film intensity S. aureus was, on average, 1.4 times faster than E. coli, for roughness 0.16 ±0.018 micron film formation process took place equally for S. aureus and E. coli, but biofilms were lower in density than those formed on roughness 0.63 ±0.087 micron. Studies suggest that the use of equipment in the dairy industry with a roughness of less than 0.5 microns will reduce the attachment of microorganisms to the surface and reduce the contamination of dairy products. [ABSTRACT FROM AUTHOR]

Interaction between two periodontal pathogens, Porphyromonas gingivalis and Treponema denticola, contributes to plaque biofilm formation. Porphyromonas gingivalis forms aggregates with T. denticola through its adhesion/hemagglutinin domain (Hgp44). In this study, we investigated the specific domain of P. gingivalis Hgp44 responsible for adhesion to T. denticola using expression vectors harboring P. gingivalis Hgp44 DNA sequences encoding amino acid residues 1–419. Six plasmids harboring fragments in this region were generated by PCR amplification and self-ligation, and recombinant proteins r-Hgp44 (residues 1–419), r-Hgp441 (residues 1–124), r-Hgp442 (1–199), r-Hgp443 (1–316), r-Hgp444 (199–419), r-Hgp445 (124–198) and r-Hgp446 (199–316) were produced, as confirmed by sodium dodecyl sulfate–polyacrylamide gel electrophoresis and immunoblotting. r-Hgp44, r-Hgp443 and r-Hgp446 showed greater adhesion to T. denticola sonicates than the control, as determined by enzyme-linked immunosorbent assay. r-Hgp446 reduced the coaggregation of P. gingivalis and T. denticola. Scanning electron and confocal laser scanning microscopy analyses revealed that r-Hgp446 reduced dual-species biofilm formation. Our results indicate that residues 199–316 of P. gingivalis Hgp44 are mainly responsible for adhesion to T. denticola; inhibiting this domain could potentially disrupt periodontopathic biofilm formation and maturation. Porphyromonas gingivalis Hgp44 residues 199–316 are responsible for adhesion to Treponema denticola; inhibition of this domain may disrupt periodontopathic biofilm formation and maturation. [ABSTRACT FROM AUTHOR]

In this study, we investigated the potential adhesion of marine bacteria isolated from seawater in the port of Chmaâla, Morocco, to sea-immersed 304 and 316 stainless steels using thermodynamic approach and the Environmental Scanning Electron Microscopy (ESEM). Furthermore, the physicochemical properties including hydrophobicity and electron donor / electron acceptor (Lewis acid-base) of bacterial isolates and both substrates were evaluated using the contact angle measurements. The molecular identification indicated that the isolated strains wereBacillus thuringiensisandBacillus amyloliquefascience.Results also showed that both bacterial strains’s cells have a hydrophilic character with ΔGiwivalues of 29.30 and 24.12 mJ m−2respectively forBacillus thuringiensisandBacillus amyloliquefascience, and are strong electron donating (γ−) and weakly electron accepting (γ+). For substrates surfaces, we found that both sea-immersed stainless steels types were hydrophilic and present strong electron-donor character (γ− = 49 ± 0.2 mJ m−2for 304 andγ− = 55.07 ± 0.02 mJ m−2for 316) and weak electron-acceptor character (γ+ = 5.4 ± 0.1 mJ m−2for 304 andγ+ = 8.3 ± 0.06 mJ m−2for 316). The theoretical prediction showed that both tested strains,B. thuringiensisandB. amyloliquefascience,exhibited positive values of ΔGTotalvis-à-vis the two sea-immersed stainless steels types which indicates unfavorable adhesion while the ESEM electro-micrographs show that both strains were able to adhere to both strainless steels surfaces. [ABSTRACT FROM PUBLISHER]

Biofilm-based bioprocesses are increasingly used in wastewater treatment. Microbial adhesion constitutes the key step in stability of these depollution systems. For adhesion studies, physicochemical characterization of microbial cells and supports has proved to be of extreme importance. In this work, estimation of interaction between five yeast strains with a high potential for Cr (VI) removal using extended Derjaguin-Landau-Verwey and Overbeek (XDLVO) theory as a powerful predictive tool of adhesion was investigated. Predictions showed that wood husk could be a good support for the formation of tested yeast biofilm, beech and oak exhibit better properties than other wood species studied with 100% of potential for adhesion. From a thermodynamic point of view, pine and teak woods are not suitable for biofilm formation for all tested yeast strains, presenting positive values of free energy adhesion (ΔGXDLVO). Environmental scanning electronic microscopy (ESEM) and Matlab® image analysis confirmed that all tested yeast strains were able to adhere to pine wood and, except for Wickerhamomyces anomalus they were unable to adhere to oak wood. Adhesion experiments were found to be well related to the theoretical prediction. To our knowledge, this is the first study dealing with biofilm-mediated depollution from an adhesion point of view aiming to optimize the stability of the system. It allows expanding knowledge about adhesion phenomena of yeast strains on wooden surface and contributes to select the best biofilm-support combination that would be used in a performant biological system for chromium removal. [ABSTRACT FROM AUTHOR]

An understanding of adhesion behavior of Candida and Pichia yeast under different environmental conditions is key to the development of effective preventive measures against biofilm-associated infection. Hence in this study we investigated the impact of growth medium and temperature on Candida and Pichia adherence using stainless steel (AISI 304) discs with different degrees of surface roughness (Ra = 25.20–961.9 nm), material typical for the food processing industry as well as medical devices. The adhesion of the yeast strains to stainless steel surfaces grown in Malt Extract broth (MEB) or YPD broth at three temperatures (7 °C, 37 °C, 43 °C for Candida strains and 7 °C, 27 °C, 32 °C for Pichia strains) was assessed by crystal violet staining. The results showed that the nutrient content of medium significantly influenced the quantity of adhered cells by the tested yeasts. Adhesion of C. albicans and C. glabrata on stainless steel surfaces were significantly higher in MEB, whereas for C. parapsilosis and C. krusei it was YPD broth. In the case with P. pijperi and P. membranifaciens , YPD broth was more effective in promoting adhesion than MEB. On the other hand, our data indicated that temperature is a very important factor which considerably affects the adhesion of these yeast. There was also significant difference in cell adhesion on all types of stainless steel surfaces for all tested yeast. [ABSTRACT FROM AUTHOR]

The ability of Lactococcus lactis to adhere to the intestinal mucosa can potentially prolong the contact with the host, and therefore favour its persistence in the gut. In the present study, the contribution of plasmid-encoded factors to the adhesive and transit properties of the L. lactis subsp. cremoris IBB477 strain was investigated. Plasmid-cured derivatives as well as deletion mutants were obtained and analysed. Adhesion tests were performed using non-coated polystyrene plates, plates coated with mucin or fibronectin and mucus-secreting HT29-MTX intestinal epithelial cells. The results indicate that two plasmids, pIBB477a and b, are involved in adhesion of the IBB477 strain. One of the genes localised on plasmid pIBB477b (AJ89_14230), which encodes cell wall-associated peptidase S8 (PrtP), mediates adhesion of the IBB477 strain to bare, mucin- and fibronectin-coated polystyrene, as well as to HT29-MTX cells. Interactions between bacteria and mucus secreted by HT29-MTX cells were further investigated by fluorescent staining and confocal microscopy. Confocal images showed that IBB477 forms dense clusters embedded in secreted mucus. Finally, the ability of IBB477 strain and its ΔprtP deletion mutant to colonise the gastrointestinal tract of conventional C57Bl/6 mice was determined. Both strains were present in the gut for up to 72 h. In summary, adhesion and persistence of IBB477 were analysed by in vitro and in vivo approaches, respectively. Our studies revealed that plasmidic genes encoding cell surface proteins are more involved in the adhesion of IBB477 strain than in the ability to confer a selective advantage in the gut. [ABSTRACT FROM AUTHOR]

The initial adhesion of microorganisms on a substrate is a significant step for biofilm formation. In this work, the contact angle measurement method was used to investigate the effect of three Myrtus communis extractives on the physicochemical properties of cedar wood surface. Indeed, hydrophobicity, electron donor ( γ − ) electron acceptor ( γ + ) parameters and surface tension components (ΔGiwi) of untreated and treated wood were assessed. The results indicated that all extractives tested decreased the hydrophobic parameter and made the cedar wood surface more donor electron. Moreover, the theoretical prediction and the experimental assay of Thielavia hyalocarpa adhesion on untreated and treated substrates were also investigated. According to the values of total free energy of interaction ( Δ G Tot ) , the adhesion of the fungal strain studied on wood was found favorable. However, the treatments made the adhesion conditions unfavorable. Likewise, environmental scanning electron microscopy (ESEM) showed a decrease in cell adhesion with treatment, indicating the highest anti-adherence activity of methanol fraction. Furthermore, a linear relationship between theoretical prediction and experimentally determined adhesion has been obtained. [ABSTRACT FROM AUTHOR]

Contact angle measurement of microorganisms is often described in literature, either to investigate their hydrophobic characteristic or the adhesion behavior of cells. However, in some key aspects the preparation methods differ. Thus, it is difficult to compare results and to choose a procedure for repetition of measurements. The aim of this paper is to point out some critical points during microorganism film preparation that can alter the resulting contact angles. Depending on the moisturizing medium and equilibration time, contact angles differ significantly. [ABSTRACT FROM AUTHOR]

Microbial adhesion to natural and synthetic materials surfaces is a key issue e.g. in food industry, sewage treatment and most importantly in the biomedical field. The current development and progress in nanoscale structuring of materials surfaces to control microbial adhesion requires an advanced understanding of the microbe-material-interaction. This study aimed to investigate the nanostructure of the microbe-material-interface and link it to microbial adhesion kinetics as function of titanium surface nanoroughness to gain new insight into controlling microbial adhesion via materials’ surface nanoroughness. Adhesion of Escherichia coli and Staphylococcus aureus was statistically significantly reduced (p ≤ 0.05) by 55.6 % and 40.5 %, respectively, on physical vapor deposited titanium thin films with a nanoroughness of 6 nm and the lowest surface peak density compared to 2 nm with the highest surface peak density. Cross-sectioning of the microbial cells with a focused ion beam (FIB) and SEM imaging provided for the first time direct insight into the titanium-microbe-interface. High resolution SEM micrographs gave evidence that the surface peaks are the loci of initial contact between the microbial cells and the material’s surface. In a qualitative model we propose that the initial microbial adhesion on nanorough surfaces is controlled by the titanium surface peak density via nano adhesion points. This new understanding will help towards the design of materials surfaces for controlling microbial adhesion. [ABSTRACT FROM AUTHOR]

The aim of this study was to develop photoreactive surface coatings, possessing antibacterial properties and can be activated under visible light illumination ( λ max = 405 nm) using LED-light source. The photocatalytically active titanium dioxide (TiO 2 ) was functionalized with silver nanoparticles (Ag NPs) and immobilized in polyacrylate based nanohybrid thin film in order to facilitate visible light activity ( λ Ag/TiO2,max = 500 nm). First, the photocatalytic activity was modelled by following ethanol vapor degradation. The plasmonic functionalization resulted in 15% enhancement of the activity compared to pure TiO 2 . The photoreactive antimicrobial (5 log reduction of cfu in 2 h) surface coatings are able to inactivate clinically relevant pathogen strains (methicillin resistant Staphylococcus aureus , Escherichia coli , Pseudomonas aeruginosa ) within short time (60–120 min) due to the formed and quantified reactive oxygen species (ROS). The existence of electrostatic interactions between the negatively charged bacteria (from −0.89 to −3.19 μeq/10 9 cfu) and positively charged photocatalyst particles (in the range of +0.38 and +12.3 meq/100 g) was also proven by charge titration measurements. The surface inactivation of the bacteria and the photocatalytic degradation of the cell wall component were also confirmed by fluorescence and transmission electron microscopic observations, respectively. According to the results an effective sterilizing system and prevention strategy can be developed and carried out against dangerous microorganisms in health care. [ABSTRACT FROM AUTHOR]

Background: Recently, extracts from natural sources have been tested for their antifungal properties. In this aspect, Flammulina velutipes extracts possess a significant amount of branch-chained carbohydrates with mannose moieties that, hypothetically, can reduce the adhesion. Objective: In this study, we assessed the capacity of extracts from F. velutipes (wild-type AQF-1 and ATCC 34574 as the reference strain) to inhibit the adhesion of S. schenkii and C. albicans to epithelial cells. Materials and Methods: The aqueous extracts from F. velutipes strains were obtained by sonication, total carbohydrate and protein was analyzed by Dubois and Lowry methods respectively. Effect of the extracts (50, 100 and 150 µg/mL) on the fungi adhesion to host cells was evaluated after 1 h interaction, and the percentage of inhibition of adhesion was measured. After of interaction the cytoskeleton from cell was analyzed with phalloidin-FITC. Results: The extract from strain AQF-1 (50, 100 and 150 µg/mL) inhibited the adhesion of: S. schenkii in a dose-dependent manner (4.9, 7.5 and 12.7%, respectively) and C. albicans in a dose-independent manner (5.2%). The percentage of inhibition by extracts from the strain ATCC34574 at the same concentrations, shown that are dose independent for both fungi: 3.9% for S. schenkii and 2.6% for C. albicans. Conclusion: The extracts from F. velutipes inhibit the adhesion of pathogenic fungi to host cells. The mechanism molecular is unknown; however, is probably an interaction between the polysaccharides from extracts with the fungi receptors. This aspect is currently analyzed. [ABSTRACT FROM AUTHOR]

This study evaluated the capacity of real-time PCR and conventional culture methods to detect Salmonella enterica serovar Typhimurium and Listeria monocytogenes adhered to stainless steel surfaces used as food contact surfaces. The adhesion of the microorganisms to the surfaces was performed under dry conditions to represent the stress to which these pathogens can be subjected in the food processing environment. The samples were analyzed with various pre-enrichment times: S. Typhymurium (0, 6, and 18 h) and L. monocytogenes (0, 6, and 25 h) and with procedures concentrating or not concentrating the samples after the pre-enrichments. The results showed that real-time PCR obtained increased capacity than the conventional method to detect a low number of both pathogens, and real-time PCR even detected samples without pre-enrichment. However, pre-enrichment is recommended to avoid the detection of false positives from dead cells during adhesion and to ensure the absence of false negatives due to low initial concentrations. The concentration of the adhering bacteria increased the frequency in the detection of positive results for S. Typhimurium, but this effect was not observed in the case of L. monocytogenes. • Detection of Salmonella Typhimurium and Listeria monocytogenes adhered to surfaces under dry conditions. • High capacity of real-time PCR detection compared to conventional culture method. • Pre-enrichment is recommended to avoid false positives. • Concentration of samples increases S. Typhymurium detection. [ABSTRACT FROM AUTHOR]

Objective In vitro evaluation of the effect of guaraná (GUAR) on cell surface hydrophobicity (CSH), on biofilm formation, and on adhesion of C. albicans to polystyrene, to composite resins, and to buccal epithelial cells (BEC). Materials and methods Lyophilised aqueous extract of GUAR was tested on C. albicans ATCC (90028). The effect of GUAR was evaluated by examining the CSH of C. albicans , as determined by microbial adhesion to hydrocarbons test, by assessing biofilm production and through adhesion assays (microplates of polystyrene, BEC and composites). One nanoparticle (Z350 ® ) and two microhybrid (LLis ® , Opallis ® ) composites were tested. Scanning electron microscopy (SEM) was used to analyse adhesion of C. albicans composites. Assays were performed in triplicate and the results analysed by Chi-square test, Kruskal–Wallis test and Dunn's Multiple Comparison post hoc test at 5% significance level. Results GUAR did not inhibit growth of C. albicans at any concentration, but it reduced adhesion to polystyrene surface ( p < 0.001). Exposure to GUAR did not change CSH and biofilm formation, but it increased adhesion of C. albicans to the nanoparticle composite ( p = 0.042) and reduced its adhesion to BEC ( p < 0.001). SEM confirmed an aggregatory pattern of adhesion of C. albicans to composites. Conclusion GUAR increased the adhesion of C . albicans to the surface of the nanoparticle composite. However, it reduced the adhesion of C. albicans to BEC and to polystyrene, which reveals its potential use in prevention of oral diseases. [ABSTRACT FROM AUTHOR]

Entamoeba histolytica is an enteric tissue-invading protozoan parasite that causes amoebic colitis and occasionally liver abscess in humans. During tissue invasion, amoebic adhesion to host components is an important event for host cell death leading to successful invasion and infection. Among amoebic virulence factors, Gal/GalNAc lectin is known to be major adhesion factor to host cells. In this study, we investigated the role of amoebic secreted CP (Cysteine Proteases) in amoebic adhesion to extracellular matrix (ECM) protein using CP inhibitor and E. histolytica strains in which the endogenous inhibitor of cysteine protease (ICP) 1 gene was overexpressed (ICP1 + ) or repressed by antisense small RNA-mediated gene silencing (ICP1 − ). We found that pretreatment of wild-type amoebae with CP inhibitor E64, or thiol-group modifiers such as diamide and N -Ethylmaleimide resulted in a significant decrease in adhesion to laminin and collagen ECM proteins. Furthermore, ICP1 + strain, with a reduction of secreted CP activity, exhibited reduced ability by 40% to adhere to laminin. In contrast, ICP1 − strain, with a 1.9-fold increase of secreted CP activity, showed a two-fold increase in amoebic adherence to laminin compared to the control strain. In addition, total amount of secreted CP5 was decreased in ICP1 + amoeba. Conversely, total amount of secreted CP1 and mature-form CP5 were increased in ICP1 − amoeba. We also found that ICP1 was secreted into extracellular milieu. These results suggest that secreted CP activity by E. histolytica may be an important factor affecting adhesion to host proteins, and regulation of CP secretion by ICP plays a major role in pathogenesis. This study provides insight into the CP-mediated tissue pathogenesis in amoeba-invaded lesions during human amoebiasis. [ABSTRACT FROM AUTHOR]

Aims: To evaluate the phenotypic expression of auto-aggregation, adhesion to mucin and biofilm formation of lactobacilli isolated from human vagina and the presence of related genes. Methods and Results: Seven different strains of three Lactobacillus species (Lactobacillus gasseri, Lactobacillus rhamnosus and Lactobacillus reuteri) were evaluated. The auto-aggregation property was determined by spectrophotometric assay and flow cytometry. Adhesion and biofilm formation were assayed by crystal violet staining. The presence of the genes encoding sortases, pilin subunits and surface proteins was evaluated by polymerase chain reactions. The two Lact. reuteri strains assayed showed high auto-aggregation, adhesion to mucin and biofilm formation ability. In these strains, the genes encoding three adhesion proteins were identified. In Lact. rhamnosus CRL (Centro de Referencia para Lactobacilos Culture Collection) 1332, pilusencoding genes were detected. In all Lact. rhamnosus strains assayed, two genes encoding for other surface proteins related to adhesion and biofilm formation were detected. Conclusions: The vaginal lactobacilli assayed exhibited phenotypic and genetic characteristics that were specific for each strain. Significance and Impact of the Study: This is the first study on autoaggregation, adhesion and biofilm formation of vaginal Lactobacillus strains by phenotypic and genetic assays. [ABSTRACT FROM AUTHOR]

Even though Arcobacter butzleri has been implicated in some human disease as diarrhoea and bacteraemia, much of its pathogenesis and virulence factors remain unclear. In this work we have compared pathogenic and genotypic properties of six A. butzleri isolates from human and non-human sources. The tested isolates showed to be susceptible to tetracyclines and aminoglycosides, however non-human isolates were all resistant to quinolones. The ability to form biofilms was variable among the tested strains, and all of them showed a weak haemolytic activity. The presence of nine putative virulence genes was determined, with cadF , ciaB , cj1349 , mviN , pldA , tlyA being detected in all strains, while irgA (3/6), hecA (5/6), hecB (4/6) were detected only in some strains. High levels of adhesion were observed for A. butzleri on Caco-2 cells, with pre-existing inflammation showing no significant effect on the adherence ability; yet variable levels of invasion were observed. A. butzleri isolates were able to survive intracellularly in Caco-2 cells and to induce a significant up-regulation of interleukin-8 secretion and structural cell rearrangements. These data brings new insights on A. butzleri virulence and highlights its pathogenic potential. [ABSTRACT FROM AUTHOR]

Background: Smokers are more prone to oral infections than are non-smokers. Cigarette smoke reaches the host cells but also microorganisms present in the oral cavity. The contact between cigarette smoke and oral bacteria promotes such oral diseases as periodontitis. Cigarette smoke can also modulate C. albicans activities that promote oral candidiasis. The goal of this study was to investigate the effect of cigarette smoke condensate on C. albicans adhesion, growth, and biofilm formation as well as the activation of EAP1, HWP1 and secreted aspartic protease 2. Results: Cigarette smoke condensate (CSC) increased C. albicans adhesion and growth, as well as biofilm formation. These features may be supported by the activation of certain important genes. Using quantitative RT-PCR, we demonstrated that CSC-exposed C. albicans expressed high levels of EAP1, HWP1 and SAP2 mRNA and that this gene expression increased with increasing concentrations of CSC. Conclusion: CSC induction of C. albicans adhesion, growth, and biofilm formation may explain the increased persistence of this pathogen in smokers. These findings may also be relevant to other biofilm-induced oral diseases. [ABSTRACT FROM AUTHOR]

Highlights: [•] TRA1 transcription is strongly induced on germination. [•] Tra1p is required for normal adhesion germination appressorium formation and virulence. [•] Tra1p-dependent genes were identified using microarray technology. [•] TDG2 is predicted to encode a transcription factor which appears to be functionally related to Tra1p. [•] Tra1p dependent gene product Tdg4p is also required for normal infection-related development. [ABSTRACT FROM AUTHOR]

The first step of infection is the adhesion of pathogens to target cells. This feature not only allows them to penetrate and deploy offensive strategies to initiate colonization, but to contribute to their protection and preservation against both the immunological and mechanical defense mechanisms of the host. This process is conducted largely by the interaction of lectins, which are proteins of non-immune origin with the ability to recognize and bind carbohydrates. This mechanism has been reported for many microorganisms such as bacteria and viruses. In the particular case of Pasteurella multocida, which is a Gram-negative, opportunistic pathogen bacterium that starts the infection in the respiratory epithelium of many animals, lectin substances have been described on its surface, such as type IV fimbria, and carbohydrates such as lipopolysaccharide or the capsule that recognizes carbohydrates and lectins, respectively, on the surface of epithelial cells of the trachea, a circumstance that allows it to adhere and escape the mucociliary effect. Seeing as, to most of these microorganisms--including P. multocida--the decreased susceptibility to antibacterial agents and the effectiveness of vaccines is evident, new therapeutic and prophylactic tactics have been sought in order to interrupt pathogenic infection by blocking the carbohydrate-lectin bond by competition, where the union of the microorganism to the tissue and, therefore, the infection, is diminished. [ABSTRACT FROM AUTHOR]

Abstract: Objective: This study investigated the effect of experimental photopolymerized coatings, containing zwitterionic or hydrophilic monomers, on the hydrophobicity of a denture base acrylic resin and on Candida albicans adhesion. Methods: Acrylic specimens were prepared with rough and smooth surfaces and were either left untreated (control) or coated with one of the following experimental coatings: 2-hydroxyethyl methacrylate (HE); 3-hydroxypropyl methacrylate (HP); and 2-trimethylammonium ethyl methacrylate chloride (T); and sulfobetaine methacrylate (S). The concentrations of these constituent monomers were 25%, 30% or 35%. Half of the specimens in each group (control and experimentals) were coated with saliva and the other half remained uncoated. The surface free energy of all specimens was measured, regardless of the experimental condition. C. albicans adhesion was evaluated for all specimens, both saliva conditioned and unconditioned. The adhesion test was performed by incubating specimens in C. albicans suspensions (1×107 cell/mL) at 37°C for 90min. The number of adhered yeasts were evaluated by XTT (2,3-bis[2-methoxy-4-nitro-5-sulfophenyl]-5-[{phenylamino}carbonyl]-2H-tetrazolium-hydroxide) method. Results: For rough surfaces, coatings S (30 or 35%) and HP (30%) resulted in lower absorbance values compared to control. These coatings exhibited more hydrophilic surfaces than the control group. Roughness increased the adhesion only in the control group, and saliva did not influence the adhesion. The photoelectron spectroscopy analysis (XPS) confirmed the chemical changes of the experimental specimens, particularly for HP and S coatings. Conclusions: S and HP coatings reduced significantly the adhesion of C. albicans to the acrylic resin and could be considered as a potential preventive treatment for denture stomatitis. [Copyright &y& Elsevier]

Abstract: Microbial adhesion to an interface plays an important role in many industrial bioengineering processes. Surface physicochemical properties can be treated as an indicator of the adhesive properties of microbial cells. In this paper, the application of the aggregation/dispersion technique used in fine particle technology to biotechnology is reviewed. By way of illustration, measurements of the surface characteristics of microbes living in an anaerobic digester, analysis of microbial adhesion and aggregation/coaggregation, and their application are introduced. [Copyright &y& Elsevier]

Paracoccidioidomycosis is a systemic mycosis caused by the dimorphic fungus Paracoccidioides brasiliensis. Understanding the interactions between P. brasiliensis and the host tissue depends on the study of the different steps of the process of colonization, especially adhesion, in which the pathogen recognizes ligands on the surface of host cells. This study aimed to verify the role of enolase in the host cell-fungus interaction and the ability of enolase to bind to extracellular matrix components, to determine its subcellular localization, and to study the P. brasiliensis enolase amino acid sequence. The data revealed that fibronectin is the major ligand of enolase. Evaluation of the location of enolase at an ultrastructural level revealed that it is distributed in various cellular compartments, but at a high level in the cell wall. The analysis of the amino acid sequence revealed an internal plasminogen-binding motif (254 FYKADEKKY262), which is conserved in most organisms and described as an important interaction site of the enolase with the host cell surface. This suggests that enolase performs additional functions related to the glycolytic pathway and also plays a role of adhesion in P. brasiliensis. Therefore, this study increases the knowledge about the characteristics of enolase and its influence on the binding process of P. brasiliensis. [ABSTRACT FROM AUTHOR]

Abstract: Microchannels made of polymeric materials usually have wall velocity slip. Sometimes, these microchannels are not smooth. Wall roughness is introduced by manufacturing processes or caused by adhesion of biological particles from the liquids. For a proper design and operation of these microchannels, it is important to secure an accurate value of zeta potential, which determines the volumetric flow rate of electroosmotic flows. Zeta potential of microchannels is usually determined by measuring the streaming potential. In the present investigation, we have derived a simple formula that predicts accurately the streaming potential of microchannels having wall roughness and Navier velocity slip, and investigated how the streaming potential is affected by wall roughness, slip coefficient, zeta potential and bulk ionic concentration. The simple formula, which requires numerical solution of three sets of Stokes equation sequentially using a small grid number, yields very accurate results as compared with the numerical solution of nonlinear partial differential equations employing a very large number of grids. It is found that the streaming potential per pressure drop increases with respect to slip coefficient and decreases with respect to wall roughness hight. On the other hand, the streaming potential per volumetric flow rate increases as the wall roughness increases. [Copyright &y& Elsevier]

Initial microbial adhesion to surfaces is a complicated process that is affected by a number of factors. An important property of a solution that may influence adhesion is pH. The surface properties of the cedar wood were characterized by the sessile drop technique. Moreover, the interfacial free energy of surface adhesion to the cedar wood was determined under pH values (2, 3, 5, 7, 9 and 11). The results showed that cedar wood examined at different pH levels could be considered hydrophobic ranged from Giwi = −13.1 mJ/m to Giwi = −75 mJ/m. We noted that the electron-donor character of cedar wood was important at both basic and limit acidic conditions (pH 11 and pH 3) and it decreased at intermediate pH (pH 5). The cedar wood substratum presents a weak electron acceptor under various pH's. In addition, the adhesion of conidia from Penicilllium expansum to the cedar wood surfaces at different pH values (2, 3, 5, 7, 9 and 11) was investigated using Environmental Scanning Electron Microscopy and image analysis was assessed with the Mathlab program. The data analysis showed that the conidia from P. expansum were strongly influenced by the pH. The maximum adhesion occurs in the pH 11 and pH 3 and decreased to 24% at pH 5. [ABSTRACT FROM AUTHOR]

Abstract: Some strains of the food borne pathogen Listeria monocytogenes persist in food processing environments. The exact reason behind this phenomenon is not known, but strain differences in the ability to adhere to solid surfaces could offer an explanation. In the present work, initial adhesion of nine strains of L. monocytogenes was investigated under liquid flow at two levels of shear stress on six different surfaces using a flow chamber set-up with microscopy measurements. The surfaces tested were glass and PVC, and glass coated with beef extract, casein, and homogenised and unhomogenised milk. In addition, the effect of prior environmental stress (5% NaCl, low nutrient availability) on initial adhesion was investigated. The hydrophobicity of the investigated surfaces was determined by contact angle measurements and the surface properties of the investigated L. monocytogenes strains were determined using Microbial Adhesion To Solvents (MATS). All surfaces with the exception of PVC were found to be hydrophilic. Strain differences were found to significantly influence the initial adhesion rate (IAR) of all nine strains to all the surfaces (p<0.05) at both low and high shear stress. Furthermore, there was a significant effect of the surfaces tested (p<0.05) in the adhesion ability of almost all strains. The IAR was affected by flow rate (shear stress) as seen by a decrease in adhesion at high shear stress for most strains. A significant effect of interactions between strain-surface and strain-shear stress (p<0.001) was observed but not of interactions between surface-shear stress. No correlation between surface hydrophobicity and IAR was observed. Addition of 5% NaCl during propagation resulted in a decrease in IAR whilst propagation in low nutrient media caused an increase indicating a general change in surface characteristics under these conditions. Known persisting strains did not display general better adherence. [Copyright &y& Elsevier]

Background & objectives: Adherence of bacteria to epithelial cells and mucosal surfaces is a key criterion for selection of probiotic. We assessed the adhesion property of selected indigenous probiotic Lactobacillus strains based on their hydrophobicity and ability to adhere to human epithelial cells. Methods: Five human faecal Lactobacillus isolates, one from buffalo milk and one from cheese were assessed for hydrophobicity following the microbial adhesion to hydrocarbons (MATH) method and colonization potentials based on their adherence to Caco2 and HT-29 colonic adenocarcinomal human intestinal epithelial cell lines. Lactobacillus strains that adhered to Caco2 and HT-29 cell lines were quantified by plating after trypsinization and simultaneously the adhered bacteria were also examined microscopically after staining with Geimsa stain and counted in different fields. Results: Among the tested faecal isolates, L. plantarum Lp91 showed maximum percentage hydrophobicity (35.73±0.40 for n-hexadecane and 34.26±0.63 for toluene) closely followed by L. plantarum Lp9 (35.53±0.29 for n-hexadecane and 33.00±0.57 for toluene). Based on direct adhesion to epithelial cells, L. plantarum Lp91 was the most adhesive strain to HT-29 and Caco2 cell lines with per cent adhesion values of 12.8 ± 1.56 and 10.2 ± 1.09, respectively. L. delbrukeii CH4, was the least adhesive with corresponding figures of 2.5 ± 0.37 and 2.6 ± 0.20 per cent on HT-29 and Caco2 cell lines. Adhesion of the six isolated Lactobacillus strain to HT-29 cell and Caco2 lines as recorded under microscope varied between 131.0 ± 13.9 (Lp75) to 342.7 ± 50.52 (Lp91) and 44.7 ± 9.29 (CH4) to 315.7± 35.4 (Lp91), respectively. Interpretation & conclusions: Two Indigenous probiotic Lactobacillus strains (Lp9, Lp91) demonstrated their ability to adhere to epithelial cell and exhibited strong hydrophobicity under in vitro conditions, and thus could have better prospects to colonize the gut with extended transit. [ABSTRACT FROM AUTHOR]

Microbial biofouling is important in a variety of applications including reverse osmosis membranes and in-situ bioremediation. The initial microbial adhesion plays the key role in microbial biofouling on abiotic surfaces, which can be explained in terms of microbial surface properties. This research investigated the interactions of three indigenous bacteria with the porous medium of silica sand and their corresponding initial attachment. Traditional and extended DLVO forces were calculated based on independently measured bacterial and medium surface thermodynamic properties and were related to bacterial attachment observations. Lifshitz-van der Waals, electrostatic and Lewis acid/base forces were found to be strongly dependent on the separation distance between bacteria and the medium surface. It was concluded that the electrostatic force served as the barrier preventing the bacterial strains from getting close to the medium. Once the bacterial strains overcame the barrier with the aid of hydrodynamic forces, Lifshitz-van der Waals force and electrostatic force dropped while Lewis acid/base force increased with the decrease of separation distance. Consequently, Lewis acid/base force became the dominating force controlling bacterial adhesion. [ABSTRACT FROM AUTHOR]

Magnaporthe oryzae germlings tightly attach to the host surface by producing extracellular matrix (ECM) from germ tubes and appressoria, which are important for the early infection process. To understand the adhesion mechanisms of ECM during differentiation of infection structure, we evaluated the effects of various enzymes on M. oryzae germlings and the disease symptoms of the host plant, wheat. Treatment with β-mannosidase, collagenase N-2, collagenase S-1, or gelatinase B at 1-h postinoculation (hpi) resulted in germling detachment, although producing normal appressoria. Treatment with matrix metalloproteinases (MMPs) at 6 hpi also caused germling detachment. Furthermore, we confirmed by the inoculation tests and scanning electron microscopy that the germlings on the wheat plant were removed and did not manifest pathogenicity on treatment with MMPs. The most effective MMPs were crude collagenase, collagenase S-1, and gelatinase B, suggesting that the application of MMPs is promising for crop protection from fungal diseases by its detachment action. [ABSTRACT FROM AUTHOR]

Abstract: Soya bean tempe is known for its bioactivity in reducing the severity of diarrhoea in piglets. This bioactivity is caused by an inhibition of the adhesion of enterotoxigenic Escherichia coli (ETEC) to intestinal cells. In this paper, we assessed the bioactive effect of soya tempe on a range of ETEC target strains, as well as the effect of a range of cereal and leguminous substrates and starter pure cultures. Soya bean tempe extracts strongly inhibited the adhesion of ETEC strains tested. All tempe made from other leguminous seeds were as bioactive as soya bean tempe, whereas tempe made from cereals showed no bioactivity. Using soya beans as substrate, fermentation with several fungi (Mucor, Rhizopus spp. and yeasts) as well as Bacillus spp. resulted in bioactive tempe, whereas fermentation with lactobacilli showed no bioactivity. The active component is released or formed during the fermentation and is not present in microbial biomass and only partly in unfermented substrates. The bioactivity being not specific for a single ETEC strain, makes the bioactive tempe relevant for applications in animal husbandry. [Copyright &y& Elsevier]

Abstract: Two primary selection criteria were used to collect a pool of nearly 500 candidate probiotic bacteria from Atlantic cod (Gadus morhua L.) larvae, i.e. the dominant intestinal bacterial flora and isolates with antagonistic activity against Vibrio anguillarum. Bacteria were isolated from cod larvae from five rearing groups with variable rearing technologies. The bacteria were brought to pure culture and characterized phenotypically. Based on properties such as uniqueness, dominance and fermentative ability, a selection of ∼10% of the isolates were chosen from the initial pool of bacteria to reduce the number of candidates. These 55 isolates were characterized further in vitro regarding antagonism, adhesion to mucus, growth in mucus, production of extracellular enzymes, fish bile resistance and haemolytic properties. Based on the results of the in vitro tests, the number of probiotic candidates was further reduced to seven isolates. To evaluate the probiotic potential and to assure that the seven isolates were not harmful to the host, yolk sac larvae of cod were exposed to the isolates in a small-scale in vivo experiment. The in vivo experiment excluded two of the candidate bacteria due to increased mortality of cod larvae, whereas three isolates from the dominant (Vibrio and two different strains of Microbacterium) and two from the antagonistic (Ruegeria and Pseudoalteromonas) group improved the survival of larvae compared to the positive control. Thus, a combination of the two screening methods was suited for making multistrain probiotics with complementary modes of action. [Copyright &y& Elsevier]

Abstract: Objective: To investigate whether parylene coatings over denture bases and silicone elastomers can effectively reduce Candida albicans adhesion and thus to decrease the incidence of denture stomatitis. Design: Specimens of silicone elastomers A-2186 or lucitone 199 resin were prepared, and the measurements of contact angle, assay of XTT reduction and cell count of C. albicans adhesion were taken before and after parylene treatment. Furthermore, morphology of C. albicans adhesion for 48h was observed by scanning electron microscope (SEM), and C. albicans adhesion for 4h was illustrated by confocal scanning laser microscopy (CLSM) in combination with fluorescent dyes FUN-1 and Concanavalin A. Result: There was a statistical difference between mean contact angles of silicone elastomer A-2186 before and after parylene coating (P <0.05). The amount of C. albicans adhesion to the surface of silicone elastomer A-2186 and lucitone 199 resin after parylene treatment was significantly less than before parylene treatment by cells count and XTT reduction assay (P <0.05). In SEM and CLSM analysis, C. albicans biofilm was more apt to generate on the surface of silicone elastomer A-2186 than other three groups, and more C. albicans aggregation formed on the surface of silicone elastomer A-2186 and lucitone 199 resin before parylene treatment than after parylene treatment. Conclusion: Parylene coating reduced C. albicans adhesion and aggregation on the surface of silicone elastomer A-2186 and lucitone 199 resin, and improved the wettability of silicone elastomer A-2186. [Copyright &y& Elsevier]

Shear-enhanced adhesion, although not observed for fimbria-mediated adhesion of oral Actinomyces spp., was noted for Hsa-mediated adhesion of Streptococcus gordonii to sialic acid-containing receptors, an interaction implicated in the pathogenesis of infective endocarditis. [ABSTRACT FROM AUTHOR]

Abstract: Aims: Aqueous extracts from the roots of Glycyrrhiza glabra L. (Fabaceae) are widely used for treatment of stomach ulcer. The clinical proven effects are related to the presence of anti-inflammatory 12-keto-triterpensaponins in the extracts. Apart from that the influence of Glycyrrhiza glabra extract on the bacterial adhesion of Helicobacter pylori to stomach tissue was to be investigated. Additionally the influence of Glycyrrhiza glabra secondary compounds on the bacterial adhesion of Porphyromonas gingivalis, a major pathogen for induction of periodontal inflammations was to be investigated. Methodology: In vitro cytotoxicity against Helicobacter pylori was investigated by agar diffusion assay; antiadhesive properties of aqueous extract, raw polysaccharides and purified polysaccharide fractions was investigated by means of an in situ adhesion assay with FITC-labelled bacteria on tissue slides of human stomach resectates. Results: Aqueous extract (1mg/mL) of Glycyrrhiza glabra significantly inhibited the adhesion of Helicobacter pylori to human stomach tissue. This effect was related to the polysaccharides isolated from the extract, with one purified acidic fraction (0.25 SPB) as main active polymer. Purified polysaccharides did not exhibit direct cytotoxic effects against Helicobacter pylori and did not influence hemagglutination. Additionally raw polysaccharides from Glycyrrhiza glabra were shown to have strong antiadhesive effects against Porphyromonas gingivalis. Conclusion: Aqueous extracts and polysaccharides from the roots of Glycyrrhiza glabra are strong antiadhesive systems, which may be used as potent tools for a further development of cytoprotective preparations with anti-infectious potential. [Copyright &y& Elsevier]

Abstract: Two methods are generally used to measure the adhesive strength of invertebrate larvae: direct measurement with a force transducer connected to the organisms and indirect measurement with a water flow used to dislodge the organisms. Each of these methods, however, has its drawbacks. The present study aimed to design a simple and straightforward method to measure the adhesion strength of marine invertebrate larvae based on centrifugation. This centrifuge technique works in immersed conditions and applies forces acting at 45° to the substratum, therefore mimicking natural conditions. It was tested with three different substrata on two developmental stages of the sea star Asterina gibbosa: the brachiolaria larvae, which use temporary adhesion, and the metamorphic individuals which use permanent adhesion. Measurements were completed by SEM and TEM observations of the larval adhesive organs. The critical detachment force (force required to detach 50% of the larvae) of brachiolaria larvae attached to glass (36±9 µN) and rough PMMA (43±16 µN) were equivalent and both significantly higher than the critical detachment force measured on smooth PMMA (11±8 µN). Most metamorphic individuals, on the other hand, resisted to the highest centrifugation speed used, corresponding to a force of 2.13 mN. For the hydrodynamics of larval settlement and metamorphosis, force is the ecologically relevant factor, and adhesion forces obtained by centrifugation are strikingly similar to forces measured for other marine invertebrate larvae with other methods. This indicates the usefulness of the centrifugation technique to compare adhesion of larvae between different species or development stages, or between different treatments. [Copyright &y& Elsevier]

Aims: In the present study, we focused on one of the Aeromonas veronii isolates that exhibited marked adhesion onto carp intestine and studied its membrane-associated proteins for their possible involvement in mucosal adhesion. Methods and Results: We isolated a strain of Aer. veronii (CWP11) that exhibited a high degree of temperature-dependent adhesion activity onto carp intestinal tract and studied its adhesion factor. A proteomic analysis of the membrane-associated fraction showed the presence of multiple proteins that were specifically expressed in CWP11 cells cultured at 25°C. Of these, a 30 kDa protein was identified to be OmpA by a mass fingerprint analysis. Cloning and nucleotide sequencing of the ompA region of CWP11 revealed the presence of two tandem ompA homologues ( ompAI- ompAII). Escherichia coli that expressed either OmpAI or OmpAII exhibited marked adhesion onto carp intestinal surface. Disruption of ompAI by a homologous recombination technique resulted in marked reduction of the adhesion activity in CWP11. Conclusion: The OmpA homologue plays an important role in the adhesion of the Aer. veronii strain onto the surface of intestinal tract. Significance and Impact of the Study: We successfully identified an OmpA homologue to be an adhesion factor of Aer. veronii, an optimistic pathogen that habituates in carp intestinal tract. [ABSTRACT FROM AUTHOR]

Adhesion interaction of the most widely distributed species of microscopic fungi: Aspergillus niger, Trichoderma viride, Penicillium funiculosum, Aspergillus terreus to surfaces of materials (polymers, metals) is studied. The force of adhesion interaction was measured by the method of centrifugal detachment. Based on the analysis of kinetic curves the macroscopic characteristics of adhesion micro-organism-metal surface were obtained. We show on the example of Aspergillus niger that stochastic nature of adhesion of microorganisms cells is caused by heterogeneity of support surface, heterogeneity of conidium sizes, and their distribution by forces of adhesion obeys the Gauss law. We established that structure of cellular wall of microscopic fungi was changed in dependence on age, and change of force of adhesion interaction correlated with changes in cellular wall structure of microscopic fungi, and dominating role in strengthening of adhesion interaction was played by increase of albuminous components concentration in surface layer of cell. [ABSTRACT FROM AUTHOR]

Candida albicans and Candida dubliniensis are two pathogenic yeasts particularly hazardous to immunocompromised patients. Adhesion of yeast cells to epithelium is considered one of the virulence factors and its study is of major importance. The main aim of this study was the comparison of the influence of physico-chemical properties on the adhesion of C. albicans and C. dubliniensis to epithelium. Two strains of each Candida species were used in the adhesion assays to HeLa cells. Adhered cells were enumerated by direct microscopic images observation. Yeast cell surface tension parameters and degree of hydrophobicity were determined by contact angle measurement. Pseudohyphae and hyphae formation was analysed by scanning electron microscopy. Yeast cells presented no statistical differences concerning their physico-chemical surface properties. However, the extent of adhesion to epithelium was different among the four strains. As general conclusion, yeast adhesion to epithelium seems to be strain-dependent and not directly correlated with pseudohyphae formation. [ABSTRACT FROM AUTHOR]