High Adhesion Ability Research Articles

Screening of adhesive lactobacilli with antagonistic activity against Campylobacter jejuni

In the present study, 78 lactic acid bacteria (LAB) strains were screened for the antagonistic activity against Campylobacter jejuni and 15 LAB strains with high bactericidal capacity were selected for further study through the analysis of the inhibition zone of LAB spent culture supernatant on the growth of C. jejuni. Among these strains, four isolates, Lactobacillus plantarum N8, N9, ZL5 and Lactobacillus casei ZL4 exhibited high adhesion ability to HT-29 cells. All the cell free supernatant (CFS) of these four strains contained high concentration of organic acid and their inhibition effects against C. jejuni were pH sensitive. Furthermore, these four strains could strongly antagonize the adhesion and invasion of C. jejuni to HT-29 cells and showed good tolerance to artificial gastric and small intestinal juices. This study suggests that Lactobacillus strains N8, N9, ZL4 and ZL5 could be used as potential probiotics in food applications against C. jejuni infection.

Epoxy Resin and Polyurethane Compositions from Glycolized Poly (ethylene terephthalate) Wastes

The possibility to use poly(ethylene terephthalate) (PET) bottles production waste as raw material for compositions with high adhesion ability has been investigated. PET waste was glycolyzed with polypropylene glycol and three kinds of oligoesters were formed after depolymerization reaction. The polydispersity of product formed was 1.05. The possibilities to use PET glycolysis products – oligoesters for epoxy resin and polyurethanes were studied. Two-step reaction of oligoesters with epichlorohydrin was chosen for epoxy resin synthesis, while glycolyzed PET reaction with aliphatic isocyanate was used for polyurethane synthesis. The structure and properties of the obtained polymers were investigated. DOI: http://dx.doi.org/10.5755/j01.ms.19.3.5237

A Comparative Study of Wear and Oxidation Behaviors of End Mill Coated by PVD Coatings

The objective of this research is to study wear behaviors of TiN, nanolaminated AlCrN and nanocomposite TiAlSiN coated on cemented carbide end mill deposited by cathodic arc physical vapor deposition methods in comparison with uncoated end mill. Wear behaviors were investigated by nanoindentation hardness test, scratch test and cutting test. Oxidation test was also done in air at temperatures of 700°- 900°C in order to evaluate resistance of oxidation. In the nanoindentation hardness and scratch tests, nanocomposite TiAlSiN coating exhibited higher hardness than TiN and nanolaminated AlCrN coatings. The nanolaminated AlCrN coating represented the highest adhesion ability in terms of critical load and the lowest coefficient of friction in comparison with the TiAlSiN and TiN coatings, respectively. The cutting performance, represented in terms of maximum flank wear as a function of cutting length, was found to be highest in the AlCrN coating. Oxides of these coatings, i.e., TiO2 for TiN, TiO2 for TiAlSiN and Cr2O3 for AlCrN, generated at different temperatures of 700°, 800° and 900°C, respectively. From all of results, it is obvious that the AlCrN coating exhibited more excellent wear resistance and oxidation resistance than the uncoated end mill, TiN coating and TiAlSiN coating.

Assessment of efflux-mediated antibiotic-resistant Salmonella enterica serovar Typhimurium under simulated gastrointestinal conditions

The objective of this study was to evaluate the efflux-mediated antibiotic resistance and virulence potential in Salmonella enterica serovar Typhimurium exposed to bile salts. S. enterica serovar Typhimurium KCCM 40253, S. enterica serovar Typhimurium CCARM 8009, and plasmid-cured S. enterica serovar Typhimurium CCARM 8009 were used to evaluate the antimicrobial susceptibility, adherence ability, and gene expression in the presence of 0.3 % bile salts. The sensitivity of S. enterica serovar Typhimurium CCARM 8009 to tetracycline was significantly increased in the presence of phenylalanine-arginine β-naphthylamide (PAβN), showing the decrease in the minimum inhibitory concentration (MIC) values from 256 to 8 mg/ml. The relative ethidium bromide (EtBr) fluorescence intensity was rapidly decreased from 1 to 0.47 in S. enterica serovar Typhimurium CCARM 8009 after 20 min of exposure to bile salts. The highest adhesion ability was observed in S. enterica serovar Typhimurium CCARM 8009 exposed to both absence and presence of bile salts. The tolC and tetA genes were up-regulated in S. enterica serovar Typhimurium CCARM 8009 exposed bile salts. The results suggest that the antimicrobial resistance were positively correlated with efflux pump activity, and virulence potential in antibiotic-resistant S. enterica serovar Typhimurium when exposed to bile salts.

Adhesive ability means inhibition activities for lactobacillus against pathogens and S-layer protein plays an important role in adhesion

Eighty-five strains of lactobacillus were isolated from the pig intestine and identified by sequencing analysis based on 16S rRNA gene, from which five lactobacillus strains with high adhesive ability were selected. The inhibition ability of the five lactobacillus strains with or without S-layer proteins against adherence of Escherichia coli K88 and Salmonella enteritidis 50335 to Caco-2 was evaluated in vitro with Lactobacillus rhamnosus GG strain (LGG) as a positive control. In addition, tolerance of lactobacilli to heat, acid, bile, Zn2+ and Cu2+ were assessed. All five selected strains, Lactobacillus salivarius ZJ614 (JN981856), Lactobacillus reuteri ZJ616 (JN981858), L. reuteri ZJ617 (JN981859), L. reuteri ZJ621 (JN981863) and L. reuteri ZJ623 (JN981865), showed inhibition against the two pathogens, E. coli K88 and S. enteritidis 50335. L. reuteri ZJ621 showed higher inhibition ability than the others to S. enteritidis 50335 (P < 0.05). Sodium dodecyl sulfate-Polyacrylamide gel electrophoresis (SDS-PAGE) analysis indicated that all five strains had abundant bands with molecular weight ranging from 34 to 130 KDa as well as had a common band of approximately 42 KDa. After treatment with 5 M LiCl to remove S-layer protein, the inhibition activities of the lactobacilli against pathogens decreased significantly (P < 0.05). The results showed that higher adhesive ability means higher inhibition activity for lactobacillus against pathogen, in which S-layer proteins plays an important role.

A novel sulfur/polypyrrole/multi-walled carbon nanotube nanocomposite cathode with core–shell tubular structure for lithium rechargeable batteries

A multi-walled carbon nanotube and polypyrrole composite (PPy/MWNT) was synthesized by in situ polymerization of pyrrole monomer on the surface of MWNT. As-prepared PPy/MWNT composite was mixed with an aqueous suspension of nanosized sulfur particle, followed by heat-treatment to obtain an S/PPy/MWNT ternary composite. High resolution transmission electronic microscopy shows the formation of a highly developed core–shell tubular structure consisting of PPy/MWNT composite with uniform sulfur coating on its surface. Polypyrrole, with its high adhesion ability to MWNT, acts as a binder to connect sulfur and MWNTs, as well as absorbs polysulfides into its porous structure to improve the cyclability of the S/PPy/MWNT composite in Li/S batteries. The MWNT core provides a highly conductive and mechanically flexible framework, enhancing the electronic conductivity and consequently the rate capability of the material. This ternary composite cathode sustains 960.7 mAh g− 1 reversible specific discharge capacity after 40 cycles at 0.1 C, and 523.2 mAh g− 1 at 0.5 C.

Characterization of Campylobacter spp. transferred from naturally contaminated chicken legs to cooked chicken slices via a cutting board

Campylobacter represents the leading cause of gastroenteritis in Europe. Campylobacteriosis is mainly due to C. jejuni and C. coli. Poultry meat is the main source of contamination, and cross-contaminations in the consumer's kitchen appear to be the important route for exposure. The aim of this study was to examine the transfer of Campylobacter from naturally contaminated raw poultry products to a cooked chicken product via the cutting board and to determine the characteristics of the involved isolates. This study showed that transfer occurred in nearly 30% of the assays and that both the C. jejuni and C. coli species were able to transfer. Transfer seems to be linked to specific isolates: some were able to transfer during separate trials while others were not. No correlation was found between transfer and adhesion to inert surfaces, but more than 90% of the isolates presented moderate or high adhesion ability. All tested isolates had the ability to adhere and invade Caco-2 cells, but presented high variability between isolates.Our results highlighted the occurrence of Campylobacter cross-contamination via the cutting board in the kitchen. Moreover, they provided new interesting data to be considered in risk assessment studies.

Versican V2 isoform enhances angiogenesis by regulating endothelial cell activities and fibronectin expression

Versican is a proteoglycan expressed in the extracellular matrix, where it regulates a variety of cell activities and affects tumor development. With alternative splicing, there are four versican isoforms, denoted V0, V1, V2 and V3. The V2 isoform is highly expressed in the mature brain but its function in the mature brain has not yet been elucidated. Since brain tumors are among the most angiogenic of human tumors, we investigated whether or not the V2 isoform plays a role in angiogenesis and found that the glioblastoma cell line U87 stably transfected with V2 formed tumors containing extensive vasculature. Although the V2-expressing cells grew slowly, they survived well in serum-free medium. They also displayed high adhesive ability to endothelial cells and facilitated tube-like structure formation. Importantly, fibronectin was up-regulated by V2 and mediated V2 function. Thus, versican V2 could be a potential target for intervention of brain tumor angiogenesis.

Metal-ceramics based on nanostructured boron carbide

Boron carbide has unique physicochemical and mechanical properties such as: high modulus of elasticity, high value of a strength-to-density ratio, heightened wear-resistance in unfriendly environment, etc., however dense product of boron carbide is not widely used in the area of engineering due to low impact strength, brittleness and low thermal conductivity of this material. Recent efforts of the scientists working in this area are focused on creating the so-called hetero-modulus metal-ceramic composite materials comprised of high-modulus ceramic and a metallic phase as an elastic binder. Creation of effective boron carbide based hetero-modulus materials is possible when a) boron carbide has a high degree of dispersion; b) metallic binder has a high adhesion ability and low reactivity toward boron carbide. The technology developed for producing boron carbide based metal-ceramic materials provides pyrolysis (900–1100 °C) of the precursors comprised of amorphous boron, carbon-chain polymers and appropriate metal salts. Each particle of the obtained powder contains both – nanostructured components of boron carbide and of a binding metallic phase. The fabricated metal-ceramic product has heightened parameters of impact strength and thermal conductivity in parallel with the retained unique properties of boron carbide.

ポリピロールナノ分散液を用いた樹脂上への無電解銅めっき

In electroless copper plating using a nanodispersion of polypyrrole, adhesion and the deposition mechanism were studied. Using this electroless plating method, copper plating with high adhesive ability was produced on resins while maintaining a smooth surface. Results of XPS and SEM measurements suggest that the palladium ions in catalyst solutions are reduced by electron-donating dedoped polypyrrole to give zero-valent palladium, which acts as a catalyst of electroless copper plating. The reduction effects of polypyrrole on the palladium ions operate in the direction of polypyrrole thickness. Consequently, not only the polypyrrole surface but also the polypyrrole inner layer can supply electrons for palladium ions. Regulation of the polypyrrole thickness is necessary to obtain plating with high adhesive ability. This method is applicable to various resins because high adhesion between the polypyrrole layer and resins can be accomplished by choosing suitable binders for respective resins. In addition, direct pattern plating is obtainable by the pattern printing of polypyrrole using this method because palladium catalysts are only adsorbed onto sites with polypyrrole. In summary, this method is expected to be effective as a technology for use in etching-free plating on resins.

The role of hemagglutination and effect of exopolysaccharide production on bifidobacteria adhesion to Caco-2 cells in vitro

It is believed that an important criterion for a potential probiotic strain is that it is capable of adhering to mucosal surfaces in the human gastrointestinal tract. The purpose of this study was to investigate a possible relationship between exopolysaccharide production and adhesion to Caco-2 cells by Bifidobacterium breve A28 and Bifidobacterium bifidum A10. In a preselection process, the hemagglutination abilities of these bacteria were determined prior to undertaking adhesion studies. B. breve A28, which produces large amounts of EPS (97.00 ± 2.00 mg/l) and has good hemagglutination abilities (+3) was found to adhere strongly to Caco-2 cells. Under gastrointestinal conditions, the high EPS producing- B. breve A28 was found to have better viability and adhesion to Caco-2 cells than the low EPS producing- B. bifidum A10. Also, B. breve A28 was found to be more effective at inhibiting Escherichia coli ATCC 11229 than B. bifidum A10. This investigation showed that high EPS production and adhesion ability may be important in the selection of bifidobacteria as probiotic strains.

Influence of cell surface properties on adhesion ability of bifidobacteria

Adhesion ability of bifidobacteria to the intestinal mucosa is considered to be the prerequisite for colonization of bifidobacteria and can protect against gastrointestinal pathogens infection. The aim of this study was to investigate bifidobacterial surface traits related to adhesion ability in vitro and characterize the cell surface substances that may be involved in the adhesion process of bifidobacteria. Twelve strains of Bifidobacterium spp. were studied for the correlation among their adhesion ability, autoaggregation ability and surface hydrophobicity. The strain that exhibited good adhesion ability also showed high degree of hydrophobicity and strong autoaggregation ability. Pepsin treatment had negative effect on the surface traits and adhesion ability of B. bifidum KLDS2.0603 (P < 0.01), it revealed that hydrophobicity, autoaggregation and adhesion process maybe mediated by proteinaceous components on the surface of cell. Moreover, the adhesion and autoaggregation ability decreased after extraction of B. bifidum KLDS2.0603 with 5 mol l−1 LiCl, and an unreported 50-kDa surface protein which can bind to Caco-2 cell was observed by western blotting. Our results indicated that surface hydrophobicity and autoaggregation ability can be used together for preliminary screening the strains with high adhesion ability, and the present of the surface proteinaceous components would contribute to understand the interactions between bifidobacteria and human intestinal mucosa.

Adhesives and compounds in manufacture of electronic mechanisms

The general properties of adhesives and compounds for electronic articles are described that were elaborated by the company: TK-1 adhesive with elevated thermal conductivity; TEK-type adhesives that demonstrate higher elasticity and adhesion ability; TK-8-type all-purpose adhesives; MS-type, single-packed, thermally stable glues for long storage; electrically conductive adhesives; TPK-1 and TPK-2 magnetic adhesives and TPK-3 nonmagnetic adhesive; and some compounds, e.g., epoxide molding compositions. The functionality of all adhesives and compounds presented were tested for weather factors, including elevated humidity, higher and lower temperatures, thermal cycles, effects of vibrations for both pilot samples, and final articles of electronic mechanisms.

Mussel-inspired fabrication of encoded polymer films for electrochemical identification

Encoded polymer films for electrochemical identification have been achieved by embedding different semiconductor nanocrystals into self-polymerized dopamine films. Such encoded polydopamine films based on mussel-inspired surface chemistry show high adhesive ability and can be created on a wide range of inorganic and organic materials, including noble metals, oxides, ceramics, and synthetic polymers. By incorporating different predetermined levels of various redox nanomarkers, the use of multi-film system composed of multiple, sequenced polydopamine identification films could theoretically generate nearly unlimited (>10 12) distinct voltammetric signatures (electric codes).

Cancer stem cell‐like SP cells have a high adhesion ability to the peritoneum in gastric carcinoma

Cancer stem cells (CSCs) are considered to be responsible for cancer metastasis, but the evidence to conclusively prove this hypothesis remains uncertain. The side population (SP), as evaluated by a flow cytometric analysis using Hoechst 33342, has been known as CSC-rich population. The aim of this study was to clarify the characterization of the SP cells in peritoneal metastasis of gastric carcinoma. Gastric cancer cell lines OCUM-2M, OCUM-2D, and OCUM-2MD3 (a daughter cell line with high potential for peritoneal metastasis) were used. We isolated SP cells from OCUM-2M and OCUM-2D using flow cytometry. Serial sorting was performed three times to enrich SP cells, and they were designated as OCUM-2M/SP and OCUM-2D/SP cells. Flow cytometric analysis showed 0.46%, 0.29%, 5.24%, 6.49%, and 11.3% of the SP cells to be found in OCUM-2M, OCUM-2D, OCUM-2MD3, OCUM-2M/SP, and OCUM-2D/SP cells, respectively. The intraperitoneal inoculation of SP cells and OCUM-2MD3 cells produced peritoneal metastasis, but parent cells did not. The adhesion ability of SP and OCUM-2MD3 cells was significantly high in comparison to that of parent cells. The expression level of adhesion molecules alpha2-, alpha5-, beta3-, and beta5-integrin, and CD44, was high in SP cells compared to parent cells. The expression of stemness markers, Oct3/4 and Sox2, increased in the SP-cell-injected tumors. These findings suggested that CSC-like SP cells expressing alpha2-, alpha5-, beta3-, and beta5-integrin, and CD44, may play an important role for peritoneal metastasis in gastric carcinoma. Oct3/4 and Sox2 may be associated with CSC in gastric cancer.

Probiotic properties of Lactobacillus rhamnosus and Lactobacillus paracasei isolated from human faeces

The possibility of using microbes to maintain health, and to prevent or treat disease is a topic as old as microbiology. The research of novel probiotic strains is important in order to satisfy the increasing request of the market and to obtain functional products in which the probiotic cultures are more active and with better probiotic characteristics than those already present on the market. In this study, the probiotic potential of Lactobacillus strains isolated from Italian elderly human faeces was investigated. The Lactobacillus strains were identified and examined for resistance to gastric acidity and bile toxicity, adhesion to HT-29 cells, antimicrobial activities, antibiotic susceptibility and plasmid profile. Survival of the strains through human intestine was examined in a 3 months human feeding trial. Two strains, Lactobacillus rhamnosus IMC 501 and Lactobacillus paracasei IMC 502, tolerated well low pH and bile acids. In antimicrobial activity assays, both strains showed inhibitory properties towards selected potential harmful microorganisms, particularly against Candida albicans. The two selected strains expressed high in vitro adherence to HT-29 cells increasing this characteristic when they are used in combination and they were resistant to vamcomycin, colistin sulphate, gentamicin, oxolinic acid and kanamycin. Moreover, the two strains could be recovered from stools of volunteers after the feeding trials. Lactobacillus rhamnosus IMC 501 and L. paracasei IMC 502 present favourable strain-specific properties for their utilisation as probiotics in functional foods and the high adhesion ability of the L. rhamnosus IMC 501 and L. paracasei IMC 502 used in combination, confirmed by both in vitro and in vivo study, indicate that the two bacterial strains could be used as health-promoting bacteria.

Study of the epoxyline resin ED-20 hardening by modified oligoaminoamide dimerizated fatty-acid derivates

Resin ED-20 hardening by an oligoaminoamide hardener is analyzed by the differential scanning calorimetry (DSC) method. The optimal resin-to-hardener proportion is determined. Physical, mechanical, and thermal characteristics of the hardened polymers are determined. The high adhesive ability of the oligoaminoamide mixture towards steel is analyzed.

Capture of bacteria by flexible carbon nanotubes

Capture of bacteria with flexible carbon nanotubes (CNTs) was done in vitro. Bundles of single-walled carbon nanotubes (SWCNTs) or multi-walled carbon nanotubes (MWCNTs) was mixed with Streptococcus mutans. Precipitation assays and colony-forming unit formation assays showed free S. mutans in the solution was significantly decreased by the addition of the CNTs. Observation of the precipitate by scanning electron microscopy showed bacterial adhesion to CNTs. It has been shown that CNTs of different diameters have significantly different effects on the precipitation efficiency, and the manners in which they capture the cells are different. We found that MWCNTs (diameter of approximately 30nm) had the highest precipitation efficiency, which was attributable to both their adequate dispersibility and aggregation activity. From observations by scanning electron microscopy, bundles of SWCNTs and thin MWCNTs (diameter of approximately 30nm), which were moderately flexible, were easily wound around the curved surface of S. mutans. Bare CNTs having high adhesive ability could be useful as biomaterials, e.g., as tools for the elimination of oral pathogens at the nano-level.

Adhesive and Chemokine Stimulatory Properties of Potentially Probiotic Lactobacillus Strains

Five Lactobacillus plantarum strains and two Lactobacillus johnsonii strains, stemming either from African traditionally fermented milk products or children's feces, were investigated for probiotic properties in vitro. The relationship between the hydrophobic-hydrophilic cell surface and adhesion ability to HT29 intestinal epithelial cells was investigated, and results indicated that especially the L. johnsonii strains, which exhibited both hydrophobic and hydrophilic surface characteristics, adhered well to HT29 cells. Four L. plantarum and two L. johnsonii strains showed high adherence to HT29 cells, generally higher than that of the probiotic control strain Lactobacillus rhamnosus GG. Most strains with high adhesion ability also showed high autoaggregation ability. The two L. johnsonii strains coaggregated well with the intestinal pathogens Listeria monocytogenes Scott A, Staphylococcus aureus ATCC 25923, Escherichia coli ATCC 25922, and Salmonella enterica serovar Typhimurium ATCC 14028. The L. plantarum BFE 1685 and L. johnsonii 6128 strains furthermore inhibited the adhesion of at least two of these intestinal pathogens in coculture with HT29 cells in a strain-dependent way. These two potential probiotic strains also significantly increased interleukin-8 (IL-8) chemokine production by HT29 cells, although modulation of other cytokines, such as IL-1, IL-6, IL-10, monocyte chemoattractant protein-1 (MCP-1), tumor necrosis factor alpha (TNF-α), and transforming growth factor β (TGF-β), did not occur. Altogether, our results suggested that L. plantarum BFE 1685 and L. johnsonii BFE 6128 showed good adherence, coaggregated with pathogens, and stimulated chemokine production of intestinal epithelial cells, traits that may be considered promising for their development as probiotic strains.

Derivatization, characterization, and tribological behavior of an amine-terminated polymer surface

The derivatization, characterization, and micro-tribological behavior of an amine-terminated polymer surface were investigated. Thus, the heptafluorobutyric anhydride (HFBA) derivatized film was characterized by means of contact-angle measurement and X-ray photoelectron spectroscopy (XPS). It was found that the HFBA-derivatized film was generated on the PEI surface in the presence of a chemical amide bond. The tribological properties were characterized as well. The polymer PEI film had relative high adhesion, friction, and poor anti-wear ability, while the HFBA-derivatized polymer film possessed a very low adhesive force of only about 5.5nN (a pyramidal Si3N4 tip with radius of curvature about 50nm was used to measure the adhesion), which was more than an order of magnitude lower than that of the silicon substrate surface. Besides, the HFBA-derivatized film registered good friction-reducing ability and thermal stability. Thus, a good alternative method was presented to improve the tribological properties of polymer film by chemisorbing molecules with low surface energy. This makes it feasible for the derivatized polymer film to find promising application in resolving the tribological problems of micro-electromechanical systems (MEMS).